Abstract

Previous studies have established a relationship between foreign direct investment and environmental quality, but have stopped short of proving a consistent positive or negative impact on human health. The following study examines the relationship between foreign direct investment, PM2.5, and infant mortality across countries from 1990-2020, with specific attention to income groups. Using weighted averages and regression analysis, this study concludes no statistically significant relationship globally with infant mortality. However, when countries are separated by income groups, distinct patterns emerge. Upper middle income countries reveal a strong and positive relationship between FDI and infant mortality, while low income countries have a marginally significant relationship. Finally no significant relationship is found within lower middle income and high income countries. In particular, the significant relationship within upper middle income countries suggests the possibility that environmental consequences that come with foreign investments may influence infant health. Further research in urbanization, PM2.5, and GDP per capita further demonstrate the results of dependence on each country’s stage of development. Overall, these results demonstrate the relationship is not universal between FDI and infant mortality which emphasizes the importance of delving deeper within specific levels of economic development instead of relying on a single global relationship.

1. Introduction

Foreign direct investment is seen as a stimulant that creates jobs and economic growth promoting a country’s well being, but it may also be the silent killer in the case of air pollution. The most intense and dangerous particle is PM2.5, fine airborne particles smaller than 2.5 micrometers that can bypass the human body’s natural filters (World Health Organization, n.d.). Children and infants are particularly susceptible due to their still developing lungs and immune systems (Institute for Health Metrics and Evaluation, 2025). Furthermore, exposure to air pollution during pregnancy has shown to leave newborns with low birth weight, as well as an increase in preterm birth and infant mortality (Health Effects Institute, 2025). 

This study tests which theory holds across 186 countries by examining the relationship of foreign direct investment, air pollution, and infant mortality, while taking into account urbanization, GDP, and income groups. Using a weighted cross-country sample of 186 nations from 1990 to 2020, this study finds that the effect of foreign direct investment on infant mortality is not universal but varies systematically by income level. In upper-middle-income countries, higher FDI inflows are strongly and significantly associated with higher infant mortality rates (p = 0.002), consistent with a pollution-mediated mechanism. A marginally significant positive effect is also observed in low-income countries (p = 0.062). No significant effect is detectable globally or in high-income countries, where institutional quality and healthcare systems appear to absorb the environmental costs of foreign investment.

2. Background/Data/Methods

Researchers continue to debate the impact of FDI on environment quality. The pollution halo hypothesis argues that multinational corporations can introduce cleaner technologies, while the pollution haven hypothesis suggests that rigorous pollution industries are simply relocated to countries with weaker economic regulations (Cole et al., 2017). Singhania and Saini (2021) examined 21 countries from 1990-2016 directly supporting the pollution haven hypothesis and found that FDI can contribute to environmental deterioration. Contrastingly Heft-Neal et al. (2018) found a strong relationship between PM2.5 and infant mortality through analyzing one million births across sub Saharan Africa. Together these studies suggest a potential connection between FDI, pollution, and infant health that has often been studied separately. 

The data for this study comes from the World Bank’s World Development Indicators and includes 186 countries while varying income levels. The primary variables are foreign direct investment (FDI) as a percentage of GDP, PM2.5 air pollution, and infant mortality. Along with GDP per capita and urbanization. Countries are also classified into low, lower middle, upper middle, and high income as classified by the World Bank Group using Gross National Income per capita. 26 countries qualify for low income with under $1,175 income per capita, 53 lower middle countries ($1,176- $4,635), 53 upper middle income countries with $4,636-$14,375, and lastly 54 high income countries categorized under high income for over $14,376. Weighted averages were used to summarize each country’s data across the 1990-2020 period into a representative value, allowing long term patterns to be compared across countries rather than focusing on short term yearly fluctuations and recent periods having disproportionate influence. Then using weighted ordinary least squares (OLS) regression, the statistical analysis reflected the weighting of the data. A global regression was conducted using the full sample, but resulted in no strong relationship so the countries were split into income groups to examine hidden relationships.

3. Results and Discussion

From 1990-2020 FDI fluctuated greatly, but overall increased for much of the period while PM2.5 generally decreased substantially which suggests no simple aggregate relationship  between greater foreign investment and greater pollution.  

However the histograms show a wide range for countries.FDI is relatively low for most countries with a few very high outliers while PM2.5 levels are more distributed revealing that countries can have various combinations of FDI and pollution.

This variation across countries suggests other factors have an impact on the environmental consequences of FDI, instead of FDI automatically contributing to higher pollution. The global model verifies this pattern with an R-squared value of 0.53. The near zero coefficient of 0.002 indicates for every one percentage point increase in FDI, infant mortality is associated with an increase of 0.002 deaths per 1,000 births, effectively zero. Additionally the p-value of 0.99 suggests there is almost no statistical evidence that FDI has a direct impact on infant mortality. 

Separate regressions by income group reveal that FDI has a significant positive relationship with infant mortality in upper middle countries and a marginally significant relationship in low income countries, while no significant relationship is seen in lower middle and high income countries. Average FDI increases in high income countries, while average PM2.5 decreases from 32.6 to 21.5 mcg/m3.

 The FDI time series graph additionally displays these differences by showing the volatility where high income groups tend to have many extreme spikes and lower income groups remain relatively stable. 

Scatterplots between FDI vs PM2.5 and FDI vs infant mortality continue to show separation with low and lower middle income groups with higher levels of PM2.5 and infant mortality and higher income countries more centered with lower levels, despite a trend of receiving higher FDI. 

The regression results lead to a clearer picture. With a coefficient of 1.5052 and a p value of 0.0023,

Upper middle income countries have the strongest relationship between infant mortality and FDI, while low income countries follow with a coefficient of 2.2574 and a p value of 0.0621 suggesting that poorer countries may be more susceptible to negative foreign investment effects. However there is no statistically significant relationship in lower middle income countries (coefficient of -1.5753, p = 0.2051) and high income countries (coefficient of -0.0215, p = 0.5926). Lower middle income countries show that general economic development may be more relevant towards infant mortality with a p value of 0.001 with GDP where broad economic development drives infant health improvement. Higher income countries, which are associated with stronger institutions and health systems, can absorb the negative impacts of FDI therefore resulting in a weaker relationship.

Important limitations of this study include that the results prove correlation, not causation, meaning the regression cannot prove that FDI directly causes changes in infant mortality. In addition, other factors may influence both FDI and infant mortality such as government policies, healthcare access, or infrastructure. This data also does not identify the sector receiving FDI. A manufacturing plant can have very different environmental consequences than a call center. The type of foreign investment may aid in explaining differences found across income groups.

 There are also limitations within the data itself, including a low sample group of low income countries potentially making that data more sensitive to individual countries more than larger income groups. Lastly PM2.5 is measured with varying quality throughout countries, with some countries having more advanced pollution monitoring systems than others. 

4. Conclusion

Ultimately, the relationship between infant mortality and foreign direct investment is more complex than a single global trend. These differences within income groups show that the effects of 

foreign direct investment is up to the environmental and economic conditions of the country receiving it. Future research can strengthen this study by using panel data to track changes within individual countries instead of relying on averages from 1990-2020. Additionally FDI could be separated by economic sectors, such as manufacturing, to help determine whether the effects of FDI on infant health change depending on which industry receives the investment. 

Lastly, future research can investigate why the relationship differs with income groups. Specifically, researchers can examine whether strong environmental regulations weaken the relationship found in upper middle countries. Or if carbon emissions or water pollution, other measures of pollution, can be studied to see if the same pattern is continued with PM2.5. These questions can help identify the specific conditions that determine whether health outcomes are benefited or harmed by foreign investment.

Works Cited

World Bank. (2026). World Development Indicators [Data set]. World Bank DataBank. https://databank.worldbank.org/source/world-development-indicators

Cole, M. A., Elliott, R. J. R., & Zhang, L. (2017). Foreign direct investment and the environment. Annual Review of Environment and Resources, 42, 465–487. https://doi.org/10.1146/annurev-environ-102016-060916

Health Effects Institute. (2025). State of global air 2025. State of Global Air. https://www.stateofglobalair.org/

Heft-Neal, S., Burney, J., Bendavid, E., & Burke, M. (2018). Robust relationship between air quality and infant mortality in Africa. Nature, 559, 254–258. https://doi.org/10.1038/s41586-018-0263-3

Institute for Health Metrics and Evaluation. (2025). Global Burden of Disease Study 2023.

Singhania, M., & Saini, N. (2021). Demystifying pollution haven hypothesis: Role of FDI. Journal of Business Research, 123, 516–528. https://doi.org/10.1016/j.jbusres.2020.10.007

World Health Organization. (n.d.). Air pollution. https://www.who.int/health-topics/air-pollution

About the author

Avina Christie

Avina is a high school student interested in economics, environmental science, and understanding how global economic activity affects human well being. She enjoys using data to uncover patters across countries and real world issues. Outside of academics Avina loves to volunteer, play soccer, dance ballet, and spend time with family, friends, and her two dogs.

The post The Human Cost of Investment: FDI and Infant Mortality appeared first on Exploratio Journal.

Abstract

The South Bronx is one of New York City’s most diverse and densely populated neighborhoods and hosts a range of industrial facilities and highways that serve the city. These facilities affect the health of residents in the South Bronx, who face immense environmental burdens, including air pollution, water contamination, and loss of green space. Addressing these issues requires examining their historical roots, identifying current patterns and causes, and highlighting the community-led efforts already underway to fight environmental injustices in the area. This analysis reveals that while the South Bronx continues to contend with ecological harms, community-driven initiatives and resilience play a crucial role in addressing local inequities. It also identifies the need for equitable urban planning and policy interventions to advance environmental justice in the South Bronx and similar communities.

Introduction to The South Bronx

The South Bronx is a densely populated urban area in New York City bordering Bronx Park and the Bronx River. This region serves as a critical intersection between urban development and the health of natural ecosystems, reflecting broader challenges faced by communities throughout the South Bronx. Accordingly, land use has been a source of controversy throughout NYC’s rapid rise to one of the world’s most notable cities for its economic and cultural riches. Use of the land as a hub for industrial infrastructure, at the expense of expanded greenspace for community residents, is evidenced by the construction of the Cross Bronx Expressway and the Sheridan Expressway (now Sheridan Boulevard) from the 1950s to the 1980s, which tore through neighborhoods to provide benefits to communities and companies that reside elsewhere. These major roads have affected environmental conditions in communities adjacent to or within the South Bronx, with the most prominent examples being consistently poor air quality, increased heat exposure, and greater vulnerability to climate-related impacts. Demographically, the locality is made up of predominantly low-income communities of color,
populations that have long faced socio-economic disruptions and challenges. Because of this unique combination of dense urban development and environmental challenges, the South Bronx neighborhood provides a valuable case study for examining environmental justice and community-led climate resilience in New York City.

The History of Environmental Racism

The disproportionate exposure to ecological harms that the South Bronx faces is not accidental. For decades, urban planning officials have purposefully sited toxic or hazardous facilities in communities of color, with one of the most frequent places being the South Bronx. This process is often referred to as environmental racism, and it has been a growing issue.

According to South Bronx Unite, a community-led organization that advocates for social, environmental, and economic justice in neighborhoods of the South Bronx, the majority of The Waterfront Place, located in the Port Morris neighborhood of the South Bronx, sits on a 96-acre plot of public waterfront land leased in 1991 to Harlem River Yards. The plot is currently subleased to a range of industries, most notably FreshDirect, a 5,000-ton-per-day waste transfer station, and several fossil-fuel peaker power plants. This issue, in an area that has accumulated many hazardous facilities emitting pollutants into nearby residential areas, has been a longstanding one throughout the Bronx (“The Mott Haven-Port Morris Waterfront Plan”).

Figure 1: Freeways intersecting South Bronx neighborhoods. (“Reimagine the Cross Bronx Expressway Final Vision”)​

Figure 1 above, included in a recent report by Segregation by Design, visualizes the rapid development in the South Bronx in the 1900s and further shows how prior city planning has foregrounded the environmental racism that groups in the Bronx now face. The report explains how the construction of expressways and urban projects in the 1950s and 1960s physically divided the South Bronx, displaced more than 60,000 residents, and hindered the progress of hundreds of homes and businesses, with the latter also bearing economic consequences. The Cross Bronx Expressway was constructed from 1948 to 1972 under Robert Moses, a U.S. state and municipal official who oversaw much of New York’s landscape transformation through public works planning. The expressway (the broad horizontal yellow highway, in Figure 1) split densely populated neighborhoods and demolished thousands of homes and businesses, harming much of the area’s economic potential and making it a key factor behind the low income rates and stifled economic growth the area now faces (“Reimagine the Cross Bronx Expressway Final Vision”). Despite backlash from tenant activism and community protests, the expressway was built, permanently altering the socioeconomic status of the South Bronx.

Asthma Alley and Its Economic Consequences

Unfortunately, the South Bronx’s designation as “Asthma Alley” is not an overstatement; the area has recorded asthma hospitalization rates up to five times the national average (“Asthma Alley”).

Figure 2: Distribution of Youth Asthma-Related Emergency Room Visits in NYC (Monegro)

Figure 2 illustrates the growing impact of air pollution in the South Bronx (highlighted within the black circle) by showing the stark distribution of Child Asthma-Related Emergency Room (CARER) visits across NYC neighborhoods. Highways release large amounts of nitrogen dioxide (NO₂) and fine particulate matter (PM₂.₅), mainly from tire wear, vehicle exhaust, and brake dust. Children in close proximity to these roadways repeatedly inhale these pollutants, which can clog airways and trigger inflammation, damage lung tissue, and increase the frequency and severity of asthma attacks (“Health – Respiratory Diseases.”). Hence, the density of major roads and highways in the South Bronx area correlates directly with asthma rates among youth. As seen in Figure 2, wealthier and predominantly whiter neighborhoods, such as Lower Manhattan, Williamsburg, or Long Island City, experience little to no CARER visits. Emergency room visits in lower-income areas, often in the Bronx, can be especially costly, as some families either cannot afford health insurance or are underinsured, resulting in high out-of-pocket costs. Repeated emergency room visits, medications, and follow-up care associated with childhood asthma can create significant financial strain. Out-of-pocket healthcare costs reduce the money families can spend on improving their standard of living and their children’s education. This financial burden associated with asthma treatment, coupled with the fact that caregivers often lose wages when caring for sick children, creates a cycle of poor health and financial hardship, which reinforces itself.

Why the South Bronx is a “Sacrifice Zone”

“Sacrifice zones” are often defined as populated areas with high levels of pollution and environmental hazards due to nearby toxic or polluting industrial facilities, because the health and safety of people in these communities are being sacrificed for the economic gains and prosperity of others (“Sacrifice Zones”). Historical racism is why many label the South Bronx as a sacrifice zone, highlighting the unequal consequences of industrial development for its residents.

Figure 3: Map showing industrial facilities in Harlem and the Bronx. (Monegro)

​The map above (Figure 3) shows the uneven distribution of industrial facilities in East Harlem and the Bronx (the area inside the black oval). The proposed benefit of these facilities, according to the NYC industrial plan, is that the overall concentration of facilities in the area supports 16,900 industrial jobs, accounting for 33% of all private-sector employment. However, these facilities have severe environmental impacts on nearby residents. In a 2018 interview, Joyce Hogi, then-president of the Bronx Council for Environmental Quality, discusses the implications of the facilities surrounding the 145th Street Bridge. She states that the neighborhood off the interstate bridge is among “the most polluted in America,” as it also maintains a recycling center that creates lines of garbage trucks up every street. Hogi explains that the community never wanted this development; instead, they advocated for a community park. She also frankly states that she feels her community is being “pissed on” and “not considered” when it comes to choices regarding development (Bronx Council for Environmental Quality), underlining how other forms of development that would enhance their quality of life, such as investment in green spaces, have been ignored by city officials.

Highlighting Key Trends Using Tree Equity Score

There is a clear relationship between proximity to industrial development and environmental and public health harms. Industrial facilities also benefit other parts of NYC, such as the Upper East Side, Brooklyn Heights, and Tribeca, which reputedly have some of the best waste management, food distribution, sanitation, and electricity services, all of which are made possible by the location of polluting facilities in the South Bronx. This leads to vast differences in many key variables between these affluent neighborhoods and areas throughout the South Bronx.

A valuable tool for measuring these discrepancies is the Tree Equity Score, an index created by American Forests, the oldest national nonprofit conservation organization in the United States. The score reflects whether a neighborhood has sufficient tree canopy, considering both existing tree cover and community characteristics such as income, race, health burdens, heat exposure, age, and unemployment.​

Figure 4: Tree Equity Scores in affluent NYC neighborhoods. (“Tree Equity Score”)                           

Figure 5: Tree Equity Scores in South Bronx neighborhoods. (“Tree Equity Score”)​

Figures 4 and 5 compare the Tree Equity Scores of wealthier NYC neighborhoods with neighborhoods in the South Bronx. Each score is taken from a specific segment of city blocks within each neighborhood; however, these scores are indicative of the broader circumstances of each respective area. Despite discrepancies between variables in the two types of neighborhoods, some trends are apparent.

First is the correlation between race and poverty. The South Bronx neighborhoods, which have 82–98% people of color and 53–86% poverty rates, receive low Tree Equity Scores (51–72) and are designated as high- or highest-priority for canopy coverage. By contrast, affluent neighborhoods with 6–19% people of color and 0–4% poverty rates score 92–98 and are considered low priority.

​Furthermore, communities with the greatest need have the least canopy coverage. South Bronx neighborhoods have only 8–9% tree canopy coverage, compared with a recommended 40–50%, whereas upscale areas have around 20–30% canopy coverage and already have higher overall equity scores. Neighborhoods most vulnerable to environmental and health risks are also the most underserved in terms of urban greenery.​

Tree Equity Scores corroborate multiple forms of disadvantage, not just a lack of trees or canopy coverage. The South Bronx scores were consistently worse, along with unemployment, poverty rates, health burden indices, and heat disparities. This indicates that low tree equity is part of broader socio-environmental inequality, rather than an isolated environmental issue. 

How Resilient is the South Bronx?

Resilience in any society or environment is important, as it ensures that a community or system can maintain stability in the face of disruptions. Resilience, in this case, can be assessed through the ecological, social, and infrastructural components of the South Bronx. Ecological resilience is perhaps the weakest of the three.

Ecological Resilience

As evidenced by tree equity data, the South Bronx lacks sufficient tree canopy coverage to remedy environmental harms. Higher canopy cover coincides with improved air quality, as increased tree canopy helps filter airborne pollutants and reduce particulate matter. A lack of tree cover and vegetation also impacts stormwater management. Combined sewer overflows (CSOs) are one of the South Bronx’s most persistent environmental challenges (Bronx River Alliance, “Green Infrastructure”). During heavy rainfall, the city’s combined sewer system becomes overwhelmed, causing untreated sewage mixed with stormwater to be discharged directly into the Bronx River, reducing water quality and damaging aquatic habitats. This leads to lower biodiversity. With fewer marine species and less vegetation, the ecosystem’s resilience to environmental damage is hindered. Because of CSOs, habitat fragmentation is extensive. A recent study of the Bronx River found benthic macro-invertebrate (aquatic) diversity to be extremely low, with only 2–7 species recorded at study sites and almost no pollution-sensitive species (Mahmud et al.).

Figure 6: Graph: Development vs. Ecological Diversity (Mahmud et al.).

As shown in Figure 6, the team conducted a study on how development affects Simpson’s index of the Bronx River. The Simpson index ranges from 0 to 1 (0 indicating one species dominates the ecosystem, and 1 indicating an even distribution of many species throughout the ecosystem). Clearly, there is a negative correlation between development and ecological diversity. This highlights how limited tree coverage, CSO protection, and biodiversity constrain the ecological resilience of the South Bronx.

Social Resilience

The South Bronx’s social resilience is strengthened by grassroots organizations that have come together to advocate for a more equitable present and future for their community. The Green Space Program, for example, fights to reclaim the land the South Bronx lost to buildings in the 1960s and 1970s. Included in the initiative is the Maria Sola Community Garden. The Garden is part of New York State’s “Adopt-a-Highway” program, which began in the 1990s. In 2018, when many founding members of South Bronx Unite found it underused, they stepped in to help steward it. The Garden has created a space for initiatives such as pollinator planting, stormwater management, compost, and year-round neighborhood events (The Green Space Program — South Bronx Unite). Mothers on the Move (MOM), founded in 1982, works with Latina women in the South Bronx toward a sustainable future for younger generations. MOM and the Natural Resources Defense Council (NRDC) filed a public nuisance lawsuit against New York City and the New York Organic Fertilizer Company (NYOFCo) over years of sewage odors affecting Hunts Point residents. The resulting 2010 statement in a press release by the New York City Department of Environmental Protection ended the City’s shipments of sewage sludge to the NYOFCo facility, required stronger odor-control standards for future sludge-processing facilities, funded the restoration of 1.2 acres of waterfront green space adjacent to Barretto Point Park, and mandated an independent study of odor emissions from the Hunts Point wastewater treatment plant. The outcome of this case remains one of the most significant victories in the fight for environmental justice, demonstrating the value of community organizing and resistance (New York City Department of Environmental Protection).​

Resilience of Current Infrastructure

Infrastructure resilience and the South Bronx’s productive capacity are limited. Bronx Park, Starlight, and Concrete Plant Park are different types of green infrastructure, each strengthening the resilience of the South Bronx in its own way. Bronx Park has a natural floodplain and restored river habitat, which stabilize riverbanks and help reduce intense urban heat during hotter periods. Starlight Park has rain gardens and infiltration basins, both of which reduce erosion and filter runoff during heavy rainfall. Concrete Plant Park is home to both native wetland vegetation and permeable green space, allowing residents to reconnect with the river and buffer flooding. While these South Bronx parks are effective at mitigating natural or seasonal harms, the effects of global warming have become increasingly severe, reducing their ability to meet future challenges. Additionally, the concentration of environmentally harmful facilities tends to outweigh the benefits of environmentally friendly or green infrastructure in the South Bronx, resulting in overall poor infrastructure resilience.

Case Studies of Solutions

The issues seen in the South Bronx, while unique, are also more broadly evident in other case studies in Northeast America, with two comparable examples in Philadelphia and Providence.​

In Philadelphia, as in the South Bronx, there is a risk of billions of gallons of stormwater and diluted sewage flowing into local waterways each year. To address this, the Philadelphia Water Department has devised the “Green City, Clean Waters” initiative. Implemented in 2010, with all goals set to be met by 2036, the initiative primarily focuses on developing and introducing “Green Tools” (Sell). Green Tools help absorb sewage-laden runoff after periods of intense rainfall, proving crucial for a city like Philadelphia, situated between two major rivers.

Figure 7: Diagram of green infrastructure types in Philadelphia. (“Green Infrastructure: BREC”)

Figure 7 visualizes the process of green tools and how they effectively sequester and minimize pollution in rivers. The most common types of green tools include rain gardens, bioswales, permeable pavements, green roofs, and urban tree canopies (“Green Infrastructure: BREC”).

The initiative brings greater benefits to the city as a whole. Environmentally, the increase in citywide greenery offsets much of the air pollution from car use, provides a natural means of cooling, with shade reducing the energy needed for widespread air conditioning, and improves ecosystem services such as pollination through an increase in native plants and flowers. Economically, the project creates local jobs, allowing Philadelphia youth to become more involved in the process; additionally, green spaces near residential areas can increase property values, and clean rivers encourage recreational tourism, boosting the local economy. Socially, “Green City, Clean Waters” increases access to green space, fostering community growth through more pleasant outdoor areas and collaboration in maintaining parks and neighborhood streets. Overall, it addresses all three pillars of sustainability—social, environmental, and economic (Purvis et al.)—for Philadelphia’s future.  ​

The Providence Climate Justice Action Plan foregrounds a more social approach to addressing such environmental impacts. These consequences, extreme heat, flooding, poor air quality, and limited green space, are disproportionately experienced by low-income communities and communities of color (“Providence’s Climate Justice Plan.”), underscoring a parallel to the circumstances in the South Bronx. Examples include the inclusion of environmental justice organizations, youth leaders, and local advocacy groups, who worked alongside city officials from the start of the planning process. The city gave frontline communities a meaningful role that greatly influenced final policy decisions. An example of this was the creation of Green Justice Zones, in which residents helped identify priority neighborhoods and directed public funding toward necessary projects (“Providence”).

Proposed Plan for the South Bronx

Drawing on the successes in Providence and Philadelphia, a solution to many of the South Bronx issues could be to expand green infrastructure through community-led planning that prioritizes neighborhoods with the lowest Tree Equity Scores, while minimizing automobile traffic and the further development of major roadways.

EPA Environmental and Climate Justice Grants awarded around $1 million to the Bronx River Alliance in 2024 to improve heat mitigation and air quality through tree planting and rain gardens (Crawford). While improvements have been made, they have not been enough to combat the overall environmental conditions that have consistently worsened, with summers in particular becoming dangerously hot due to the combination of concentrated energy-intensive facilities and a lack of canopy cover. However, city planners have consistently rejected proposals to locate these types of facilities in other, wealthier areas. These facilities need to run continuously, as most of New York City relies on industries based in the South Bronx. It is therefore unlikely for these facilities to be shut down or relocated from the South Bronx.

There is an opportunity for further social advocacy and grants for the South Bronx community. Groups such as the U.S. Forest Service, the Kresge Foundation, the Surdna Foundation, and the JPB Foundation fund community-based environmental justice and green infrastructure projects. There are several tangible examples. In 2023, the U.S. Forest Service received $1.5 billion under the Inflation Reduction Act, which was subsequently converted into $1 billion in grants to community-based and tribal organizations across all 50 states (“Urban Forests”). More recently, in 2025, the Kresge Foundation reported giving out $160 million in grants, of which $38.4 million was designated for environmental causes (“Grants & Social Investments”). Lastly, in 2022, the Sundra Foundation approved one of its largest grants, $2.1 million to the Right to the City Alliance (“Grants Database), with the aim of funding sustainable and affordable homes (“Home – Right to the City”)  

As demonstrated by the histories of both the Bronx River Alliance and South Bronx Unite, continuous advocacy against environmental racism and for climate justice yields tangible results. Hence, through sustained campaigning, and specific grant proposals to the previously listed organizations, these organizations can gather the required funding for street tree planting, bioswales, rain gardens, and the expansion of green roofs, ensuring that future community efforts for environmental justice in New York City prioritize the communities that currently and historically bear a disproportionate share of New York City’s environmental burdens, with perhaps the most important being the South Bronx.

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About the author

Zubin Narula-Green

Zubin Narula-Green is a senior at the United Nations International School, where he is pursuing the International Baccalaureate (IB) diploma. In recent years, Zubin has taken a strong interest in humanitarian and environmental issues and has become a passionate advocate for the rights of marginalized communities, including those highlighted in his work on the South Bronx. In the future, Zubin hopes to study Environmental Economics with a focus on Sustainable Development.

The post Beyond the Burden: Environmental Challenges and Community Resilience appeared first on Exploratio Journal.

Abstract

Solar-powered unmanned aerial vehicles (UAVs) carry no fuel, meaning their endurance is governed by a balancing act crafted between the energy harvested from sunlight and the energy consumed throughout flight, rather than conventional fuel capacity constraints. Over multi-day missions, this balance becomes hard to predict, as solar harvesting depends on the Sun’s position relative to the UAV whilst energy consumption depends on the aerodynamic forces required to sustain flight. Both of these are also affected by flight conditions and cruise altitudes, meaning a complex optimisation problem emerges. Many simplified models treat the Sun as stationary, an assumption only valid for short missions over small timeframes and distances. In this paper, solar harvesting will be modelled through a fixed panel and gimballed panel approach, where a gimballed panel traces the Sun’s position relative to the UAV and points the panel at the optimal orientation for maximum irradiance.

Overall, this paper develops a model that investigates the energy balance aforementioned, using the example of a transatlantic crossing from London to New York. There are three overarching MATLAB models that are integrated into this energy balance: great-circle navigation, aerodynamic power consumption, and solar energy harvesting. The flight parameters have been derived from steady-level flight mechanics, standardised NACA tables, photovoltaic conversion data and solar geometry. 

Having completed the simulations, it can be seen that an idealised gimballed solar panel increases total harvested energy substantially, by 62%, but much of the additional energy that it harvests cannot be stored, since the battery charge is already full during daylight hours, where there is peak harvesting. This is shown as the minimum state-of-charge only increases by 5% for a gimballed panel, starkly lower than the 62% rise in energy harvesting aforementioned. As a result, it can be said that endurance in this context cannot be governed solely by aerodynamic efficiency or solar collection gains, but by the capacity of the battery to carry energy across extended periods of insufficient insolation.

Future work on this issue should therefore treat battery capacity as a design variable to be considered alongside altitude and cruise conditions, whilst also relaxing assumptions discussed throughout. This concept has potential real-world applications in wildfire monitoring, surveillance/law enforcement, shipping, and ocean monitoring.

1. Introduction

1.1 Motivation

Solar-powered unmanned aerial vehicles (UAVs) offer the ability of extremely long endurance without the constraints provided by conventional fuel. Their endurance is governed simply by the balance and optimisation between the electrical energy harvested by the sun, and the energy consumption by the UAV in flight. As a result, solar flight is attractive for a multitude of applications that require persistent operation, over large and remote areas. Such examples include maritime search and rescue, wildfire detection and atmospheric surveying in remote areas. This concept has been demonstrated experimentally before, with AtlantikSolar achieving an 81-hour continuous flight.(Oettershagen, et al., A solar-powered hand-launchable UAV for low-altitude multi-day continuous flight, 2015)(Oettershagen, et al., Design of small hand-launched solar-powered UAVs: From concept study to a multi-day world endurance record flight, 2017) The concept explored in this paper also explores the idea of a moveable (on the pitch and roll axis) solar panel on the UAV, allowing it to maximise the electrical energy it harvests from the sun, a concept yet to be quantified by existing studies. The primary reason this has not been integrated into mainstream UAV technology is due to the aerodynamic and mass penalties of such a gimbal system, which are noted as limitations throughout.

In general, the primary difficulty with a solar-powered UAV tends to be that the energy balance of the UAV is directly proportional to the aircraft’s flight conditions and environmental. Solar collection also depends on the position of the sun relative to the aircraft (with a non-gimballed system), which varies with latitude, time of day, and season. Furthermore, aircraft energy consumption varies on the aerodynamic forces required to maintain steady-level flight in a cruise state. These forces vary significantly with changes in airspeed, air density, and lift coefficient, with air density itself varying with altitude. Consequently, due to the balancing act of these two factors, one cannot simply consider aerodynamic or solar conditions alone, creating a complex problem.

Multiple attempts have been made to simplify or solve this problem, with some choosing to limit mission distance and time as being short relative to the sun’s position, allowing it to be treated as stationary. (Klesh & Kabamba, 2009)Others provide validated airframes and power-collection models but lack investigation into cruise-altitude or even route optimisation for a multi-day mission. (Oettershagen, et al., A solar-powered hand-launchable UAV for low-altitude multi-day continuous flight, 2015)The trade-off between altitude, flight conditions, and battery margin over a multi-day mission therefore remains unestablished, and this paper attempts to address this gap.

2. Preliminaries

2.1 Steady Level Flight

The aircraft is modelled in steady, level cruise. This is primarily due to time constraints and aerodynamical complexities involved in take-off, climb, descent and landing phases, which could further complicate the solar harvesting model mentioned later on. The diagram below contains four forces acting in the aircraft’s x-z plane: lift perpendicular to the flight path, drag opposing the direction of motion, thrust along the flight path, and weight acting vertically downwards.

Figure 1 – Forces Acting on Aircraft in Steady-Level Flight

Steady level flight involves no acceleration, so these forces balance in pairs:

Together, these two conditions establish the relationship between airspeed, lift coefficient and altitude: once aircraft parameters are established, the air density at a given altitude details the airspeed required at a chosen lift coefficient. (Fidowski, Atkins, & Powell, 2019)(Anderson, 1999)

The equations for lift and drag forces are given by Equation [2] below:

If we combine Equation [2] with the lift-weight balance condition in Equation [1], we get the following, Equation [3], the airspeed required to sustain a specified lift coefficient at a particular altitude

The aerodynamic coefficients are derived from two-dimensional NACA 4415 section data. (Abbott & von Doenhoff, 1959)(Airfoil Tools, n.d.) NACA 4415 was selected due to its combination of lift-to-drag performance and sufficient thickness to accommodate both solar-cell installation and endurance structural requirements. We can calculate the Reynold’s Number of the aerofoil using Equation [4] below:

At this Reynolds number the section lift curve is markedly non-linear: the local slope falls from approximately 0.21 per degree near zero incidence to 0.06 per degree at eight degrees, a consequence of a laminar separation bubble whose extent varies with incidence. A single linear fit is therefore not representative, and the tabulated section data are used directly rather than through a lift-curve slope approximation. The drag polar is obtained by fitting the drag coefficient against the square of the lift coefficient over the same data, which does not require the lift curve to be linear. (Airfoil Tools, n.d.)(Drela, 1989)                                     

The two-dimensional data are then corrected for a finite wing. A real wing sheds tip vortices, which induce a downwash and generate induced drag proportional to the square of the lift coefficient. The downwash also reduces the effective angle of attack seen by the section, so the geometric angle of attack required to achieve a given lift coefficient exceeds the two-dimensional value by the induced angle. (Anderson, 1999)

Here, at the minimum power condition we can see that induced drag is three times the parasitic drag. This is because power is the product of the drag and airspeed, so the additional velocity dependence causes the optimum condition to be shifted to a higher lift coefficient.

The difference between these operating conditions matters for a long-duration solar flight, as maximum L/D ratio would minimise drag and therefore the energy required over a fixed distance. Since that energy is the product of the drag and the distance flown, it corresponds to a maximum range condition. On the other hand, minimum power minimises the electrical demand at each instant and therefore corresponds to a maximum endurance condition. 

Figure 2 demonstrates the comparison between maximum L/D ratio and minimum power utilising the flight parameters of our aircraft that can be found in the Appendix.

2.2 Standard Atmospheric Conditions

Air density will vary significantly across the altitude range considered. A function of air density as altitude varies can be obtained, combining the hydrostatic relationships and ideal gas laws with a linear temperature profile in the troposphere. This is given in Eq. [9] and [10] below:

The constants in the equations above are:

(International Organization for Standardization, 1975)

This model is valid up to 11km altitude. This function is utilised to calculate the airspeed required to generate lift at different altitudes, as when density falls, the aircraft must fly faster to generate the same lift at a given lift coefficient, changing the power required.

2.3 Propulsion

2.4 Solar Position

The solar power available to harvest by the aircraft is set by the irradiance incidence on the illuminated panel area, and the conversion efficiency of the photovoltaic system. Irradiance will vary continuously with geographic position, time of day, season, and altitude, so solar harvesting must be evaluated along the trajectory of its transatlantic route, rather than being treated as a constant power source.

The Sun’s position relative to the aircraft follows from the solar declination angle, the aircraft latitude, and the solar hour angle. (Duffie & Beckman, 2013)(Cooper, 1969) For a day of year n, the declination can be approximated through the following equation:

The solar elevation above the local horizontal can therefore be given through the spherical law of cosines, applied to the triangle formed by the pole, aircraft zenith, and the Sun:

2.5 Atmospheric Attenuation

The irradiance reaching the aircraft is also reduced by absorption and scattering across the atmospheric path, and as the Sun sits lower throughout the day, the longer that atmospheric path becomes. The relative optical air mass can be approximated using the Kasten-Young formulation, which accounts for atmospheric curvature, and remains finite at the horizon. (Kasten & Young, 1989)

Flying at altitude also reduces the mass of atmosphere above the aircraft, which can be accounted for by scaling the air mass by the local pressure ratio from the standard atmosphere model described in Section 2.2. The direct normal irradiance then can be placed in an empirical clear-sky attenuation model:

  Figure 3 demonstrates the effects of the differing insolation models.

2.6 Photovoltaic Conversion

The electrical power generated from an illuminated panel is:

3. Methods

The following sections detail the mathematics behind MATLAB models utilised in this study. Access to these models can be found through the GitHub repository linked here: https://github.com/rohaannarula/solar-uav-energy-model

3.1 Panel Orientation & Solar Collection

Because both of these vectors have unit length, their dot product gives the cosine of the incidence angle directly. The result is fixed above zero, since a negative value implies the Sun lies behind the panel, and no energy is collected:

Two configurations will be evaluated. The first is a flat panel, representing the roughly horizontal photovoltaic surface of an aircraft in steady-level cruise. At a maximum lift-to-drag condition, the required lift coefficient of 0.593 is established using an average cruise angle of 1.11°. This is close to the horizontal, making a flat panel assumption reasonable. Setting both orientation angles to zero reduces Eq. [20] to exactly the sine of the solar elevation:

The second configuration is an idealised gimballed panel; tracing the Sun’s position. The required orientation is obtained by equating the panel normal to the solar direction, which yields three separate component equations into two unknowns. The East component contains the roll angle and yields the pitch by dividing the North component by the Down component, which eliminates the roll term.

Two angles are enough for the three equations because the solar direction is a unit vector, so only two of its components are independent of each other. The yaw angle does not appear, as rotating the panel about its own axis does not alter the theoretical solar panel surface presented to the Sun.

In both configurations, the harvesting of solar energy is reduced significantly when solar elevation is below 5º , at which point the atmospheric path length is long enough that available irradiance becomes negligible. The gimballed panel can be treated as an idealistic case, rather than a realisable configuration, due to multiple assumptions required, such as the requirement for near vertical pitch near sunrise and sunset.

3.2 Great-Circle Route

(Fidowski, Atkins, & Powell, 2019)

A four-quadrant arctan2 function can be used throughout, in place of a simple arctan one, since dividing the sine and cosine components would discard their individual signs and therefore lose the directional element of the heading.

 The result can then be converted back into latitude and longitude for the solar and atmospheric calculations. The route is decomposed into 2000 equally spaced points and is plotted below in Figure 4.

3.3 Cruise State & Energy Balance

For each cruise altitude and flight condition, the energy balance model is calculated independently. Utilising parameters obtained from Section 2; we can calculate the required electrical power and flight time:

We can calculate solar power required using the trapezium rule, as solar power harvested varies with both time and position, and is continuously varying:

The battery can be represented as an energy reservoir with limited capacity, updated according to the net electrical power balance:

The minimum state of charge is utilised as the primary measure of mission feasibility, as it is more informative than comparing net energy expenditure. This is because a positive net balance will not guarantee that sufficient energy is available throughout the flight.

The simulation of state of charge will be repeated for each altitude, with both cruise conditions and panel configurations. I will consider a minimum SOC requirement of 30% to consider feasibility, as assumptions discussed later diminish true viability of such a large margin.

4. Results

4.1 Solar Collection 

The great-circle route from London Heathrow to JFK New York spans 5540km. If the aircraft departs at 12.00 UTC on day 172 of the year, close to June solstice, the crossing at an altitude of 3000m encompasses 5 whole day-night cycles.

Figure 5 compares solar power generated by the flat and idealised gimballed configurations. Peak values appear similar, approximately 329W when gimballed against 291W, but the gimballed curve is broader, unlike the narrow daily peak of the flat configuration. Integrated across the crossing, at maximum L/D ratio, the two configurations collect 77.37MJ and 48.17MJ respectively, so continuous gimballed tracking yields 62% more energy harvested. The differences arise at low solar elevation, where a flat panel projects only 50% of the direct beam at 30 degrees and 17% at 10 degrees, compounding the atmospheric attenuation already present. This is represented by Figure 5.

4.2 Battery State-of-Charge

Figure 6 below shows the battery state of charge over the same crossing. The battery reaches full capacity for several hours each day, meaning surplus energy harvested cannot be stored given current battery size constraints. Approximately 26.1 MJ is discarded across the maximum-L/D mission, exceeding the 22.02 MJ required to complete the crossing. Storage rather than collection is therefore the binding constraint, and the additional energy gathered by the gimballed panel does not translate proportionally into endurance. The minimum state of charge is a more useful measure of feasibility than net energy balance, as explained in section 3.3.

4.3 Panel Orientation 

According to simulation, the ideal orientation requires panel roll to sweep between approximately ±60° each day and pitch to reach nearly −80° near sunrise and sunset, a range no practical mechanism could achieve, reinforcing the treatment of the gimballed case as an upper bound. The photovoltaic panel parameters can be found in the Appendix. 

4.4 Effect of Cruise Altitude and Flight Condition

Table 1 above summarises the design variables. The energy required falls only 4.3% across the entire altitude range, because drag at fixed   is independent of air density. On the other hand, battery margin falls much more sharply, from 0.437 to 0.102 under maximum L/D ratio, since greater altitudes raises power required from 43.3 to 71.4 W while night duration is unchanged. The 30% SOC requirement is only met to approximately 5 km. In terms of flight condition chosen; maximum L/D ratio consumes 15 percent less energy at every altitude, while minimum power leaves a larger reserve because it draws less overnight. This disparity grows with altitude, and at 6000m maximum L/D fails the margin requirement at 0.275 while minimum power satisfies it at 0.374. However, maximum L/D has immense benefits over minimum power in terms of practicality. The flight time of a maximum L/D condition cruise at 3000m is 39hr longer, impractical for real-world applications. Furthermore, it can be seen that a gimballed solar panel provides 62% more energy harvested at 3000m (maximum L/D), yet its minimum SOC is only 5% greater. This proves the constraint in this model is battery capacity, as most of the extra energy harvested has been discarded before it can be used, as there is simply not the storage available.

5. Assumptions & Evaluation

The performance of a multi-day crossing is governed by the interactions taking place between aerodynamics, solar geometry and finite storage rather than a specific singular parameter. The distinction between collected and usable energy is the most indicative finding. As 26.1 MJ of excess is unused against 22.02 MJ consumed, increasing collection alone offers diminishing returns unless storage is increased or surplus energy is otherwise employed. Changes in altitude selection is consequently better treated as a storage problem than an aerodynamic or harvesting one.

Several assumptions limit the quantitative accuracy of the study. The aircraft maintains steady level cruise in still air at constant mass, with launch, climb and descent neglected. The aerodynamic model uses a NACA 4415 wing polar rather than a complete aircraft polar, omitting fuselage and tail contributions; the resulting maximum L/D of 34.4 is approximately 13% more optimistic than the value inferred from published AtlantikSolar flight data. (Oettershagen, et al., A solar-powered hand-launchable UAV for low-altitude multi-day continuous flight, 2015) (Selig, Guglielmo, Broeren, & Giguere, 1995) Moreover, the solar model assumes clear-sky direct radiation, neglecting diffuse and reflected components, and neglects the equation of time (the ‘mean sun’ versus true sun position throughout elliptical orbit). Furthermore, the use of an idealised gimballed panel should be read as an upper bound, since actuator mass, angular limits and airframe shadowing are not represented.(Cooper, 1969)Finally, it is important to note that wind, cloud and other weather variations are not represented, meaning that the calculated 30% battery state-of-charge margin is likely to diminish in real-world applications.

6. Conclusion

Endurance solar flight is limited by the energy balance detailed throughout the paper, and this study’s purpose was to determine the feasibility of a such a concept of near-perpetual flight, and in what conditions it would be possible. The paper’s approach has been to utilise pre-established components where possible, in order to reduce possible error from assumptions and to provide realistic aerodynamic and photovoltaic parameters. It also means that a further exploration of this issue could lead to design models of a bespoke aircraft design, optimised for a solar UAV.

Maximum Lift/Drag ratio is the cruise condition that allows for the lowest energy requirements whilst still fulfilling the 30% SOC requirement, with 22.02 MJ over 123.4hrs at a 3000m altitude. This is measured as the optimum conditions for such a crossing. Increasing altitude reduces the flight time, and atmospheric attenuation too, yet battery margin also decreases due to an increase in power requirements.

The use of an idealised gimballed solar panel increases solar harvesting by 62%, yet most of this amount is not usable due to the battery being full at these daytime hours. We can therefore label storage capacity as a limiting constraint, yet an increase in battery capacity could come with additional complications such as mass changes etc. For applications that require persistent operation over inaccessible areas, such as maritime rescue, marine life monitoring, or wildlife monitoring, this concept could be deployed to improve real-world applications’ efficiency.

7. Bibliography

Abbott, I. H., & von Doenhoff, A. E. (1959). Theory of wing sections: Including a summary of airfoil data. Dover Publications.

Airfoil Tools. (n.d.). NACA 4415 (naca4415-il) Xfoil prediction polar at RE=200,000, Ncrit=9. Retrieved from http://airfoiltools.com/polar/details?polar=xf-naca4415-il-200000

Anderson, J. D. (1999). Aircraft performance and design. McGraw-Hill.

Cooper, P. I. (1969). The absorption of radiation in solar stills. Solar Energy, 12(3), 333-346. doi:10.1016/0038-092X(69)90047-4

Drela, M. (1989). XFOIL: An analysis and design system for low Reynolds number airfoils. In T. J. Mueller (Ed.), Low Reynolds number aerodynamics (pp. 1-12). Springer. doi:10.1007/978-3-642-84010-4_1

Duffie, J. A., & Beckman, W. A. (2013). Solar engineering of thermal processes (4th ed.). John Wiley and Sons.

Fidowski, K., Atkins, E., & Powell, K. (2019). Introduction to aerospace engineering: Aero 201 course notes, Fall 2019. Ann Arbor, MI: University of Michigan.

International Organization for Standardization. (1975). Standard atmosphere (ISO 2533:1975). Geneva: ISO.

Kasten, F., & Young, A. T. (1989). Revised optical air mass tables and approximation formula. Applied Optics, 28(22), 4735-4738. doi:10.1364/AO.28.004735

Klesh, A. T., & Kabamba, P. T. (2009). Solar-powered aircraft: Energy-optimal path planning and perpetual endurance. Journal of Guidance, Control, and Dynamics, 32(4), 1320-1329. doi:10.2514/1.40139

Meinel, A. B., & Meinel, M. P. (1976). Applied solar energy: An introduction. Addison-Wesley.

Oettershagen, P., Melzer, A., Mantel, T., Rudin, K., Lotz, R., Siebenmann, D., . . . Siegwart, R. (2015). A solar-powered hand-launchable UAV for low-altitude multi-day continuous flight. 2015 IEEE International Conference on Robotics and Automation (ICRA), (pp. 3986-3993). doi:10.1109/ICRA.2015.7139756

Oettershagen, P., Melzer, A., Mantel, T., Rudin, K., Stastny, T., Wawrzacz, B., . . . Siegwart, R. (2017). Design of small hand-launched solar-powered UAVs: From concept study to a multi-day world endurance record flight. Journal of Field Robotics, 34(7), 1352-1377. doi:10.1002/rob.21717

Selig, M. S., Guglielmo, J. J., Broeren, A. P., & Giguere, P. (1995). Summary of low-speed airfoil data, Volume 1. SoarTech Publications.

8. Appendix

8.1 Model Parameters

All model parameters are sourced from the following sources:

(Airfoil Tools, n.d.)(Drela, 1989)(Fidowski, Atkins, & Powell, 2019)(Oettershagen, et al., A solar-powered hand-launchable UAV for low-altitude multi-day continuous flight, 2015)(International Organization for Standardization, 1975)(Selig, Guglielmo, Broeren, & Giguere, 1995)(Oettershagen, et al., Design of small hand-launched solar-powered UAVs: From concept study to a multi-day world endurance record flight, 2017)(Kasten & Young, 1989)

8.1.1 Airframe and Propulsion

8.1.2 Aerodynamic Coefficients, NACA 4415 at Re = 200,000

8.1.3 Solar & Electrical Power

8.1.4 Atmosphere & Mission

About the author

Rohaan Narula

Rohaan is a student at King’s College School, Wimbledon in the United Kingdom, with a strong passion for engineering, specifically its applications to environmental concerns. Interweaving aeronautical, mechanical and environmental engineering throughout his research serves as a method of balancing both ethical and efficiency concerns whilst not losing sight of the endless pursuit of optimisation in these fields. Outside of the academic world, he is a keen cricketer and guitarist.

The post Modelling Energy Balance for a Solar-Powered Transatlantic UAV Route appeared first on Exploratio Journal.

Abstract

Insulation is a crucial part of the building and design process of a structure. There are countless different ways of insulating a building and many are eco-friendly to mitigate how much infrastructure affects the current climate crisis. The process of insulation can improve the energy efficiency of a building significantly. Using the West Side Tennis Club, an existing historical tennis center, as an example, efficiency of the clubhouse could be majorly improved upon through an insulation update. By simulating a whole new insulation design, the heat flow of one wall section went from about 26,520 btu/h to 4,020 btu/h. Insulation is very relevant today and more education on the topic can only improve our infrastructure and environment as a whole.

Introduction

Carbon emission plays a huge role in the built environment. Right now, the built environment is a major contributor to greenhouse gas emission (Architecture 2030). To be specific, 42% of annual global CO2 emissions come from a combination of building operations, building materials, and infrastructure (Architecture 2030). Additionally, there is major growth in the built environment and it will only continue to grow. Embodied carbon is one of the main sources responsible for global warming and infrastructure releases almost half of that carbon (Architecture 2030). That is why sustainability and environmentalism are so important to this topic and why it has such a big section in this paper. There are many low carbon materials that are also biodegradable, non-toxic, and extremely effective that can take us a few steps closer to bettering our environment.

Throughout this paper the topic of insulation is discussed in depth. The focus is on wall insulation, how it is installed and how it works, as well as its application in existing and historic buildings. General wall insulation and its purpose are covered first. Then, explanations of each insulation material as well as their pros and cons. The next section goes into detail about low-carbon insulation materials and their benefits and downsides. This paper then discusses how insulation applies to existing buildings and more specifically, how it can be used in existing historical buildings. Considering the walls in historic buildings are not always accessible, alternative insulation methods are explained as well. Finally, a case study of an existing historical building and how it modified the different kinds of insulation it required is outlined. Calculations of the building insulation statistics are included.

Insulation and Air Sealing

Insulation is an integral part of a building and its general efficiency. Insulation is what allows structures to remain warm in the winter time and cool during summer. Insulation regulates temperature throughout a structure by limiting the amount of heat loss in the walls, floors, and ceilings. Insulation in walls will go in the space between the interior and exterior walls to interrupt any unwanted air coming in or any necessary air moving out. Good insulation materials must be moisture resistant, fire resistant, strong, and stable. While there are many different materials for and methods of insulation, they all must have the strength to withstand a variety of conditions. Each building is different and will require a specific additional set of requirements for its insulation method which is why there are hundreds of different insulation systems.

Air sealing and vapor management are vital elements of the insulation process. Air sealing involves locating and filling gaps or cracks in a building’s envelope or insulation. Air sealing has countless benefits: it improves air quality, humidity, comfort, and energy efficiency of a building. Gaps or cracks in a building allow air to move in and out of the envelope which worsens airflow. Airflow is important for preventing mold and mildew or other bacteria from growing. Air sealing mends the damaged airflow and keeps moisture out which makes it a very important component of a home’s insulation. Although air sealing, and insulation in general, can be expensive, there are programs in certain states like New York that can help with the cost of insulation (“EmPower+.”).

Vapor control is less of a fixed process and more of a context dependent step in insulating a building. Controlling vapor can mean anything from installing drainage planes, sealing nooks and crannies, to allowing specific areas of the house to self dry. One very common method of vapor control is simply installing a vapor barrier in the building’s walls. While effective when necessary, an analysis of the building and its specific vapor patterns may conclude that more personalized methods like the three listed above be implemented. Vapor moves differently through a building depending on climate zone and season so what prevents vapor damage in one area may not do the same in another. Finding the right way to manage vapor is very important because of the damage excess vapor can cause. Moisture will dampen and rot wood, create a comfortable home for mold, mildew, and unwanted bacteria, and ultimately cause safety issues in the building. A vapor barrier stops moist air from entering through the envelope. It can be installed almost anywhere but the attic, basement, and crawl spaces need this management most. While not as important as base insulation itself, vapor management and air sealing are finishing touches that have an extreme impact on a building’s air quality and energy efficiency. They are absolutely essential steps to achieving a comfortable, well insulated structure.

Insulation Methods

There is a great variety of types of insulation each one having its individual pros and cons. First, there is blanket/batt insulation. Blanket insulation involves placing a large sheet of a flexible insulation material, could be fibers or different kinds of wool, into studs, joints, and rafters (Pacific Northwest National Laboratory and Oak Ridge National Laboratory). One of the main pros of blanket insulation is that it is cut-to-size which means you can get custom insulation for whatever space you’re dealing with (Pacific Northwest National Laboratory and Oak Ridge National Laboratory). However this type of insulation can be moisture prone which may lead to mold or mildew (Admin Account).

Loose fill insulation involves filling studs or spaces with small fibers (Pacific Northwest National Laboratory and Oak Ridge National Laboratory). These fibers can be made of all different kinds of materials but are most commonly made up of fiberglass or cellulose (Pacific Northwest National Laboratory and Oak Ridge National Laboratory). Loose fill insulation is a great choice for oddly shaped spaces or areas with obstructions because the material is blown right in using a special blower (Pacific Northwest National Laboratory and Oak Ridge National Laboratory). However, this material cannot as easily be removed or reused like blanket insulation can. Additionally, if not properly sealed, the material can become something of a sandbox for rodents (Ori Pearl).

Foamed-in-place insulation is usually made of polyurethane polymer (Autodesk Support). You can blow this material into any cavity and it will harden to insulate the area (Autodesk Support). Precision is one of the main pros of this material as it can be sprayed into a lot of little areas. This method also has effective airtight abilities (Autodesk Support). However, in many cases the material is too airtight and negatively affects the ventilation of a home (“5 Spray Foam Insulation Problems and a Look at Alternatives 5 Problems With Spray Foam Insulation and Better Alternatives.”). Foamed-in-place insulation can also lead to mold and can have a terrible odor (“5 Spray Foam Insulation Problems and a Look at Alternatives 5 Problems With Spray Foam Insulation and Better Alternatives.”). Additionally, the material must be covered after spray or else toxic smoke becomes a very real and dangerous possibility (“5 Spray Foam Insulation Problems and a Look at Alternatives 5 Problems With Spray Foam Insulation and Better Alternatives.”). While a very effective method, there are a lot of risks that come with this method of insulation (“5 Spray Foam Insulation Problems and a Look at Alternatives 5 Problems With Spray Foam Insulation and Better Alternatives.”).

Board insulation is a rigid piece of material, usually a foamed or recycled plastic, that can be placed between walls (“The Pros and Cons of Rigid Foam Board Insulation | Ace Insulation Inc..”). Board insulation is extremely effective and can achieve great R values (“The Pros and Cons of Rigid Foam Board Insulation | Ace Insulation Inc..”). They also control moisture and reduce noise (“The Pros and Cons of Rigid Foam Board Insulation | Ace Insulation Inc..”). However, there are plenty of drawbacks. In order to install boards you need to have full access to the area and be able to completely open it up making this method extremely hard to use for existing buildings (“The Pros and Cons of Rigid Foam Board Insulation | Ace Insulation Inc..”). Boards are also not fire resistant which creates a safety hazard (“The Pros and Cons of Rigid Foam Board Insulation | Ace Insulation Inc..”). Lastly, this is one of the more expensive options for insulation (“The Pros and Cons of Rigid Foam Board Insulation | Ace Insulation Inc..”).

Radiant barriers are foil sheets that can cover plywood and reflect the sun to make the space cooler (“Radiant Barriers: Pros and Cons.”). This method is very effective for keeping attics cooler in very warm climates. While the temperature will not be fully controlled, it will be significantly less hot up there than before. Radiant barriers can also bring the duct surfaces closer to dew point which is the state at which water vapor becomes water (“Radiant Barriers: Pros and Cons.”). This creates moisture and a viable home for mold and fungi (“Radiant Barriers: Pros and Cons.”). While one solution may be to use a dehumidifier in the attic, this risk is not completely unavoidable and makes this method of insulation less than ideal.

Vacuum insulation is when the air between two walls is sucked out to stop heat transfer through air molecules (Alotaibi). This method is very energy efficient and a space saver. However, one of the major disadvantages is that if the envelope gets damaged, the insulation stops working as well and the efficiency of the building decreases significantly (Alotaibi). This is also another one of the more expensive insulation methods (Alotaibi).

Reflective insulation is the process of lining a home with a material made up of different layers of aluminum foil and spacers to reduce heat flow (Hill). The material reflects heat instead of absorbing it or passing it through into the building (Hill). By adding more layers of foil and spacers, greater R values can be achieved (Hill). Reflective insulation works well in tight spaces and can also function alongside other insulation types (Hill). However, this method is not ideal for more open spaces and requires more complicated installation (Hill). The material can also become less effective if the layers are compressed which poses a threat to longterm function (Hill).

Energy Efficient Insulation Methods

Other than comfort, the whole point of insulation is to improve the efficiency of a building. To make the whole process more sustainable low carbon materials are often used to insulate. One of the most popular low carbon materials is cellulose fibre which is made of recycled paper products (“8 Insulation Products With Sustainable Properties for a Greener Future – 2050 Materials.”). Added salts make it fire resistant and its installation makes it ideal for lofts and stone walls (“8 Insulation Products With Sustainable Properties for a Greener Future – 2050 Materials.”). The material is recyclable as well as biodegradable and provides uniform coverage (“8 Insulation Products With Sustainable Properties for a Greener Future – 2050 Materials.”). However, it can absorb moisture which decreases performance and can cause molding (“8 Insulation Products With Sustainable Properties for a Greener Future – 2050 Materials.”).

Glasswool is the lowest embodied carbon material of all mainstream materials (“Pros and Cons of Glass Wool Insulation.”). It is made of 80% recycled glass, trapped air, plant based wool, and, depending on the brand, a low carbon binder (“Pros and Cons of Glass Wool Insulation.”). While very environmentally friendly, glasswool has major downsides (“Pros and Cons of Glass Wool Insulation.”). If handled incorrectly it can cause skin irritation or damage to the respiratory system (“Pros and Cons of Glass Wool Insulation.”). It can also absorb moisture in damp or humid areas. Lastly, installation can be difficult and requires a lot of attention to detail (“Pros and Cons of Glass Wool Insulation.”).

 Wood fibre is made from natural wood, which is a renewable, non-toxic, chemical free, recyclable, and biodegradable source (“Wood Insulation Guide – Pros, Cons, and Cost.”). It is ideal for roofs, drywall, and partition walls as it can regulate humidity (“Wood Insulation Guide – Pros, Cons, and Cost.”). This is a convenient form of insulation as it can be installed at any angle (“Wood Insulation Guide – Pros, Cons, and Cost.”). This method has minimal downsides with the main ones being cost and availability (“Wood Insulation Guide – Pros, Cons, and Cost.”).

Sheep’s wool is also a renewable, non toxic, and biodegradable insulation material (Local Surveyors Direct). It is a roll of recycled fibre and sheep wool and has low embodied carbon (Local Surveyors Direct). This material absorbs both moisture and sound well (Local Surveyors Direct). One of the main cons of sheep’s wool is its need for chemical treatment (Local Surveyors Direct). Sheep’s wool can attract moths and other insects creating another step in the process (Local Surveyors Direct). There are specific genetically altered rolls of wool that will not attract insects but with the material already being expensive without this extra benefit, this is not an option for every budget (Local Surveyors Direct).

An aerogel insulation blanket is a space saving low carbon insulation material made of silica aerogel, a material that traps air (“8 Insulation Products With Sustainable Properties for a Greener Future – 2050 Materials.”). With the trapped air the material ends up being about 90% air content meaning it is very light weight (“8 Insulation Products With Sustainable Properties for a Greener Future – 2050 Materials.”). It is also hydrophobic and has low thermal conductivity (“8 Insulation Products With Sustainable Properties for a Greener Future – 2050 Materials.”). The main con to this method of insulation is that aerogel and the chemicals used in the material can be hazardous (“8 Insulation Products With Sustainable Properties for a Greener Future – 2050 Materials.”). Animal studies revealed that breathing in this material may cause harm if installed or handled incorrectly (“8 Insulation Products With Sustainable Properties for a Greener Future – 2050 Materials.”).

Another low carbon material that can make insulation fibres is hemp. This is a natural, renewable, compostable, and non toxic resource (Schutz). This is a dense and pest-resistant material making it a great choice in the long run (Schutz). It has great insulation properties. This is also a form of insulation that is super easy to install (Schutz). The only downsides to hemp fibre insulation are the availability and cost (Schutz). There is only one major hemp fibre insulation manufacturer in the US which makes the material hard to acquire and expensive (Schutz).

Plaster insulation is a blend of cork, clay, and diatomaceous earth (Sidler). It is a breathable, fire resistant material that is made from natural and renewable sources (Sidler). It is biodegradable and very easy to apply (Sidler). The material itself is very strong, meaning little dents or dings will not be noticeable, and blocks sound (Sidler). The main disadvantage to this product is the fact that plaster often cracks over time (Sidler). This can eventually lead to significant damage and costly repairs (Sidler). This is also a less convenient option if hangers, fixtures, or art needs to be hung considering the material’s strength (Sidler).

The last mainstream low carbon insulation material is straw panels. This is a renewable and biodegradable product made of natural straw (Owens). Minimal processing is required and the panels end up being suitable for most walls (Owens). One very beneficial aspect of this material is its carbon sequestration (“STRAW-BALE – Carbon Smart Materials Palette.”). The straw captures and stores carbon from the atmosphere making it an extremely environmentally efficient insulation option (“STRAW-BALE – Carbon Smart Materials Palette.”). One disadvantage of this material is that it is not included in all local codes as a building material which means if chosen, some extra paperwork may need to be filled out (Owens). Additionally, moisture can be very detrimental to the straw (Owens). If installed in a very humid place or in such a way that it may come into contact with a significant amount of moisture, straw panels most likely will not be an effective form of insulation (Owens).

Insulation in Existing Buildings

Installing insulation into an existing building can vary in difficulty depending on the building. Whether the building has some existing insulation and there is access into the walls makes all the difference when it comes to the methods used. The first step in any case is to review the building’s envelope. Repairing any cracks or leaks on the outside can make all the difference when it comes to energy efficiency (“Insulating an Existing House | Cooperative Extension Service.”). The next step is often to check the basement and attic. These are areas of homes or buildings that face extreme weather conditions and that often have direct contact with snow. Basements can be the main reasons for moisture so it is important that its insulation is up to par (“Insulating an Existing House | Cooperative Extension Service.”). It is preferable that basements are insulated from the outside so that the envelope of the building is protected (“Insulating an Existing House | Cooperative Extension Service.”). The attic can be insulated from the inside because of the protection that the roof provides (“Insulating an Existing House | Cooperative Extension Service.”); however, there are materials better suited for attics than others because of the extreme temperatures that area of the house faces. Next, the walls must be inspected. Whether there is access inside the walls or not can change the direction of the plan. From whatever information there is from the walls, it must be determined if there is existing insulation. If so, you can either remove it and replace it, which is much easier if you can open up the walls completely, or clean whatever is in there and add on to it. Either way, the inside of the wall must be vapor proofed (“Insulating an Existing House | Cooperative Extension Service.”). All moisture and bacteria should be removed so that the new insulation or insulation additions have the best chance of success.

In terms of materials, most insulation methods are technically able to be installed into existing buildings but many require removal of drywall or damage to the envelope. If that is an option for the project then material options are plentiful. If there is not great access to the wall, for example a stone wall, then the insulation options are very limited. Depending on how big a space you can open up, the main options are cut in place boards, loose fill, and foamed in place materials. However, if there is really no way to get into the wall then interior insulation may be necessary depending on the overall efficiency of the building.

Insulation in Historic Buildings

Installing or upgrading insulation in historic buildings is often very challenging because the value of the exterior and interior can restrict access to the inside of the walls. It is typically not effective to improve insulation in a historic building through the walls. Therefore, insulation through the attic and/or basement, depending on whether they are finished or unfinished, and through pipes is more realistic. Pipes and ducts can be wrapped in insulation material like mineral wool, certain rubbers, and foam insulation to improve heat loss (“Weatherization of Historic Buildings: Install Insulation (U.S. National Park Service).”). However, one of the most effective ways of improving a building’s efficiency without creating damage to the envelope is upgrading the windows. Higher quality windows do a great job of limiting unwanted air flow. Improving the windows in a home by adding another pane or adding a vacuum seal can reduce energy bills from 7% to even 30% (“How Much Energy Can New Windows Save? – KobyCo Door & Window.”). Many historic building updates have involved window improvements.

A prime example of historical window replacement was the 2007 Empire State Building renovation (“Empire State Building Retrofit: How the World’s Most Famous Skyscraper Proves Every Building Can Decarbonize.”). The Empire State Building is a famous historic building that is also still very active. Improving efficiency through wall insulation upgrades would have put a lot of peoples’ lives on hold and simply was not an option. Planners decided to improve the envelope with better windows (“Empire State Building Retrofit: How the World’s Most Famous Skyscraper Proves Every Building Can Decarbonize.”). 6,514 windows needed to be updated and brought up to code (“Empire State Building Retrofit: How the World’s Most Famous Skyscraper Proves Every Building Can Decarbonize.”). The Empire State Building was built in 1931 and therefore had a lot that needed to be brought up to code (“Empire State Building Retrofit: How the World’s Most Famous Skyscraper Proves Every Building Can Decarbonize.”). With more and more laws coming out about CO2 emissions, without renovations, the building would have faced fines of about $2.49 million a year (“Empire State Building Retrofit: How the World’s Most Famous Skyscraper Proves Every Building Can Decarbonize.”). Instead of completely replacing each and every window, which would have cost $16.3 million dollars at least, the team decided to take out, inspect, and update each window (“Empire State Building Retrofit: How the World’s Most Famous Skyscraper Proves Every Building Can Decarbonize.”). They installed new panes and spacers and added insulating gasses (“Empire State Building Retrofit: How the World’s Most Famous Skyscraper Proves Every Building Can Decarbonize.”). This ended up costing about $4.5 million dollars, roughly a third of what it would have been had they gone with complete replacement (“Empire State Building Retrofit: How the World’s Most Famous Skyscraper Proves Every Building Can Decarbonize.”). The window U-value went from 0.50 all the way down to 0.125, a sizeable jump (“Empire State Building Retrofit: How the World’s Most Famous Skyscraper Proves Every Building Can Decarbonize.”). As a result, about 54% of the building’s emissions were cut (“Empire State Building Retrofit: How the World’s Most Famous Skyscraper Proves Every Building Can Decarbonize.”). The efficiency of the project, both in terms of how well the windows work and how productive the team’s plan, makes it one of the greatest retrofits in history.

Case Study

Located in Forest Hills, Queens New York The West Side Tennis club was originally built in 1913 (Keane). Its well known stadium was built ten years later (“Outside the Box: The Revival of Forest Hills Stadium | National Trust for Historic Preservation.”). This tennis club is a very historic spot because of the numerous athletic milestones reached here. The U.S. open and Davis Cup were held there for a long time, the color barrier for the Grand Slam was broken there, and famous players like Billie Jean King played on those courts (Keane). In addition to tennis, important musicians have had historic performances at the stadium such as The Beatles, Bob Dylan, and The Rolling Stones (“Outside the Box: The Revival of Forest Hills Stadium | National Trust for Historic Preservation.”). Both structures have unique insulation due to their differing duties.

The club house was built in a classic tudor style to match the surrounding neighborhood. Therefore, without modern day insulative materials, the insulation rested on a thick envelope. Thick materials like brick, stone, and timber helped to create this barrier between the outside and inside. As time has gone on and adjustments have been made to the club, efficiency has had to be upgraded. However, the walls have never been broken into because of their historic value. Therefore, the club frequently updates its plumbing and heating systems to stay on top of insulation (Keane). Adding insulation around the existing pipes and using better quality windows has helped keep energy efficiency up to code without having to damage the walls. However, in order to make a significant improvement to the building’s efficiency, it would be necessary to add more modern insulation into the walls. This is why later on, it is proposed that the walls are opened up.

In terms of the stadium, temperature insulation was not so much of an issue as noise insulation. Originally, in 1923, the stadium was built from concrete because it was made for tennis matches and did not require an extensive amount of sound insulation (“Outside the Box: The Revival of Forest Hills Stadium | National Trust for Historic Preservation.”). However, as the stadium evolved into a concert venue and locals began complaining about the noise, which eventually led to a lawsuit, the need for renovation increased (Keleshian). The stairwells and structural pillars were lined with sound-dampening insulation mesh (Moses). This material is usually a woven mix of polyester or fiberglass (“Engineered Materials Inc..”). It can withstand weather, which is good because this is an outdoor venue, and it can convert sound waves into heat (“Engineered Materials Inc..”). Overtop of all of this is a coat of blue paint to match the aesthetics. Only certain materials could be used for this project because of its outdoor location; however, considering the demanding and specific conditions, the designers did a great job with this project. They were able to keep the rest of the stadium concrete because the bodies that fill it during concerts act as noise insulation themselves.

In order to improve the West Side Tennis Club’s efficiency as much as possible I would break open the walls and add in wool insulation as well as rigid board lining. Air space as well as the wool’s properties will prevent moisture build up. Rigid panels are extremely effective and the wool fibre filling adds protection as well as insulative, acoustic, and environmental benefits (“Rockwool”). The following values are estimated and those used to calculate the building’s measurements were also estimated using the scale image of a trash can as shown in Figure 1. The current U value of the walls, with just brick, stone, and concrete, is about 0.5, which is quite poor (Pullen). Rigid boards have an R value of about 15 for 3.5 inches of space, an estimation. The wool filling has an R value of about 14 which in combination with the rigid boards equals to about 30. This translates to a U value of 0.03 which is much better than 0.5. This improved U value makes a huge difference in wall heat flow. To find the initial heat flow, as shown in Figure 2, the wall area was multiplied by the 0.5 U value which was multiplied by the temperature difference. To find the proposed heat flow the 0.5 U value is replaced with 0.03. Based on these calculations the wall heat flow would go from about 19,370 btu/h all the way down to 1,160 btu/h.

This would be a significant improvement and along with window renovations, the whole building would be much more efficient. The current windows are traditional multi-plane casement-style windows. These probably have an U value of about 0.5. The simplest way of decreasing this value without losing aesthetics would be to purchase triple glazed windows. This would bring the U value down to about 0.20 (“StackPath”). Finding the window heat flow is a similar process by which, as shown in Figure 2, the window area is multiplied by either the initial or proposed U value which is multiplied by the change in temperature. By these calculations the window heat flow would go from about 7,150 btu/h to about 2,860 btu/h. By simple addition, this means that total heat flow of this section would decrease from about 26,520 btu/h all the way down to about 4,020 btu/h.

396 Warren St. Brooklyn is a prime example of how efficient wool insulation can be in tandem with rigid boards. The building was originally built in the 1800s and was used for horse carriages and ice cream truck parking (“Rockwool.”). The goal of the retrofit was to create a comfortable and sustainable living space using low carbon materials (“Rockwool.”). Designers also wanted to keep as much of the original structure as possible (“Rockwool.”). This along with their refusal to use fossil fuel based foams limited their insulation options (“Rockwool.”). The original building had no insulation and therefore needed it on all 6 sides (“Rockwool.”).

The plan was to create entirely new interior walls and insulate them with stone wool materials (“Rockwool.”). They also installed continuous rigid insulation boards to work alongside the wool (“Rockwool.”). The combination allowed for very great thermal, vapor, and air control (“Rockwool.”). The final combined R-value ended up being 31 which is a great jump from having no insulation whatsoever (“Rockwool.”). The blower door test even gave the structure a 0.3 on airtightness (“Rockwool.”). In terms of starting from scratch, this retrofit proves that wool and rigid boards work well to create an efficient insulation structure.

Triple pane windows have become nearly as popular as double pane windows. Lennar corporation, one of nations biggest home building companies, recently chose to install triple pane windows into over 100 homes in the Ridgefields community (“Case Study: National Builder Prioritizes Occupant Health and Well-Being.”). According to them, with these windows they were able to “not only meet but exceed energy codes in this community” (“Case Study: National Builder Prioritizes Occupant Health and Well-Being.”). The company reported little to no difference in availability or installation for these windows compared to double pane (“Case Study: National Builder Prioritizes Occupant Health and Well-Being.”). Considering the major difference in energy efficiency between these two types of windows, triple pane is the most productive choice.

Glass with a low-e coating means the window will have lower emissivity and therefore will become more energy efficient. A low-e coating can change the R value of a triple pane window from R3 to about R5 (Jennings 3). That is a great jump with minimal change to the design of the windows themselves. The window itself is not obnoxiously thick and with the right frame would still fit in with the existing building.

Conclusion

It is clear that an assessment of insulation can make a great difference in a building’s energy efficiency. There are so many different ways of insulating. So many of these methods are energy efficient which makes it unnecessary for infrastructure to be impacting the environment so negatively. In terms of the case study, there are many areas where more precision and accuracy could have been applied. More exact measurements could have been obtained through communication with the establishment but for estimation purposes the values calculated based on perspective work well. Heating and cooling systems in the building itself could have been considered but would have complicated the simple model of insulative energy improvement. Heating and cooling systems create an equilibrium of temperature through the air space and furniture to provide a stable temperature throughout the rooms. When certain insulation works well enough, it can replace these systems altogether; however, those are rare and expensive cases. Ventilation is also a factor that is important to this process but was not considered for simplicity purposes. Ventilation is the management of airflow throughout a structure (“Energy, Weatherization and Indoor Air Quality.”). With faulty ventilation could come uneven temperatures creating damp areas and/or mold and bacteria (“Energy, Weatherization and Indoor Air Quality.”). Depending on the type of insulation used, this could rot or ruin the insulation in place. Even though the scope of this case study was not large enough to include these aspects of the insulative and design process, the proposal and calculations still represent a beneficial change to the structure and the overall lesson that insulation can majorly improve a buildings energy efficiency.

Appendix

Figure 1: Displays estimated measurements of the case study. Measurements estimated by using the trash can as a scale multiplier.

Figure 2: All calculations for window and wall heat flow. Temperature estimated for cold months: When it is 10 degrees outside the club is estimated to be set at a comfortable temperature of 75 degrees. 0.5 initial U-value was estimated based on the fact that the original wall is a stone and brick cavity with some external insulation (Pullen)

Acknowledgements

I acknowledge Kurt Tiechurt for leading me through the production and editing process of this paper. I also acknowledge Danielle Joy for assistance throughout the publishing process.

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About the author

Harper Harrison

Harper a senior at Grace Church School majoring in math and hoping to pursue a career in STEM. She is currently taking an engineering course at Cooper Union to fuel this interest. She loves to design and build things which is why infrastructure has recently become one of her interests. She likes to spend her free time doing sports. She has been playing volleyball for 4 years and is the captain of her school’s cheerleading team.

The post Insulation and Its Relevance in Existing and Historic Infrastructure appeared first on Exploratio Journal.

Abstract

The automotive industry is rapidly changing together with increasingly tougher environmental regulations; including, among others, the shift towards use of low-carbon-footprint products, and ban of per- and polyfluoroalkyl substances (PFAS). The remarkable thermal stability, chemical resistance, and mechanical durability of fluorocarbon elastomers (FKMs) are essential in seals, hoses and tubings of internal combustion engines. These are difficult to match by any other materials making them so far irreplaceable.  The new regulations on PFAS, however, stimulated researchers to test the alternative non-fluorinated elastomers. These materials are additionally challenged by developments of new fuels, i.e. higher energetic synthetic e-fuels, which compromise their long-term performance. This manuscript summarizes use of FKMs in passenger cars, regulatory challenges and environmental concerns on PFAS, as well discussed technical challenges associated with substitution of fluorinated materials to be exposed with ethanol-based fuel, such as E85. Material replacement strategies, implications for road and race cars, and future developments in sealant technologies are discussed.

Introduction

Fluoroelastomers in Automotive Sealing Applications

Fluoroelastomers (FKMs) are a class of high-performance synthetic elastomers characterized by a fluorine-rich polymer backbone (60-75 wt.% fluorine), typically comprising vinylidene fluoride and hexafluoropropylene units (Scheme 1). FKMs were specifically developed to address sealing challenges in environments involving high temperatures, aggressive chemicals, and long service lifetimes, particularly in the automotive and aerospace sectors (Drobny, 2007). Places where, FKM-based parts are used in a combustion engine car are presented in Figure 1. Sealing materials used in the automotive engines and fuel systems are subjected to high temperatures, variable pressure, aggressive lubricants, and fuel compounds that are growing in complexity (Nishina, 2008). The FKMs, which are elastomers with fluorine-based polymer backbone, are characterized by an exceptional mix of heat resistance, chemical inertness, low permeability, and long service life (Moon et al., 2021). These properties have made FKMs the material of choice in critical components like O-rings, gaskets, shaft seals, injector seals, and fuel hoses, especially in areas of the engine where a failure would lead to leakage, emissions, or even safety hazards. Their elasticity and resistance to swelling and degradation have seen them become a standard material in the sealing technology of automobiles. However, currently FKM alternative sealants are also considered, such as silicone-based or nitrile-butadiene rubbers (Scheme 1). Their performance will be discussed in the sections below.

Influence of Alternative and Ethanol-Based Fuels on Elastomer Performance

The relevance of FKMs has escalated further with the diversification of automotive fuels. Blended fuels like E5, E10, and E85, biodiesel, and new synthetic e-fuels have been progressively replacing or supplementing conventional gasoline and diesel (Czerwinski et al., 2016; Muelaner, 2023). Fuel containing alcohol, e.g. higher concentration of ethanol, poses new threats to elastomeric materials because they are polar, hygroscopic, and may behave as swelling solvents. Ethanol can enter into elastomer networks, remove additives, and enhance swelling or embrittlement, ultimately degrading seal integrity (U.S. Department of Energy (DOE), n.d.). FMKs with high concentrations of fluorine (usually 69-71% fluorine) are less susceptible to these effects and have longer-lasting dimensional stability and mechanical performance even in long-term contact with alcohol-containing fuels (Stevens, 2006). This is the reason why they find extensive application in the fuel system parts, such as in-tank seals and tubing, where they are likely to be subjected to hostile fuel environments over extended periods.

PFAS Regulatory Pressure and Environmental Concerns

Although fluorinated materials have technical benefits, there is a growing wave of questioning the use of fluorinated materials because of the environmental and regulatory factors related to per- and polyfluoroalkyl substances (PFAS) (Améduri, 2023). PFAS have been referred to as “forever chemicals” due to their environmental persistence and their resistance to degradation and low bioaccumulation possibilities (Brun et al., 2023; Lee et al., 2025). Regulatory agencies, especially the European Union, are working towards general bans on PFAS that have cast doubt on the future use of fluorinated polymers in industries (European Commission, 2025). One of the main controversies is whether high-molecular-weight fluoropolymers like FKMs should be considered together with low-molecular-weight PFAS that are already known to be dangerous to the environment and health. Fluoropolymer can be subdivided into polymers where perfluorination resides either in the main chain or in the side chain (Figure 2). This differentiation is important, as in the advent of hydrolytic degradation, the perfluorinated side chains are released to the environment and their mobility and accumulation may be similar to other small molecular weight PFAS. In contrast, main-chain fluoropolymers, such as FKMs, do not hydrolyse and the risk of release of similar small molecular weight compounds is rather small.In turn, FKMs do not have high mobility and have low bioaccumulation; nevertheless, they are fluorinated in nature, which puts them in an ever-tighter regulatory environment.” FKMs do not have high mobility and have low bioaccumulation; nevertheless, they are fluorinated in nature, which puts them in an ever-tighter regulatory environment.

Sustainability Challenges and the Need for Material Substitution

This regulatory pressure is in line with an overall shift to sustainable mobility, such as the use of biofuels and e-fuels as solutions to lower greenhouse gas emission levels in internal combustion engines (Yılbaşı, 2025). Although these fuels have environmental advantages, they tend to cause compatibility challenges with materials, because they are more corrosive and chemically aggressive. This, in effect, makes it a significant technical challenge to replace fluorinated materials, as their unique performance characteristics remain difficult to replicate with non-fluorinated alternatives (Améduri, 2023). Any alternative substance cannot be inferior in terms of thermal stability, chemical resistance, elasticity, low permeability, and long durability, especially when subjected to fuels that are ethanol-based, like E85 (Sahu et al., 2022). This paper discusses the multifaceted nature of the relationship between material operation, fuel development, and regulatory requirements and explains why the substitution of FKMs remains one of the most pressing and unsolved issues in automotive material development.

Discussion

Currently Used Sealant Materials

Elastomers in Use: FKM and NBR

Fluoroelastomers (FKM) and nitrile butadiene rubber (NBR) (Scheme 1) are the most common elastomers used in automotive fuel and engine systems, chosen through a performance-to-cost ratio (Białecki et al., 2021). FKMs are normally utilized in the critical sealing processes that are subjected to high temperature, aggressive fuel, and extended working time (Asthana  et al., 2025). Their fluorine content is high, and this gives them high thermal stability, which means that they can run continuously above 200 C, and are also highly resistant to oils, fuels, and additives. Such characteristics render FKMs applicable in injector seals, O-rings, shaft seals, and in-tank fuel components. Conversely, NBR has found extensive use as a cost-sensitive component in certain applications because it is less expensive and good enough for non-polar hydrocarbon resistance of petroleum-based fuels and lubricants.

NBR reveals evident limitations despite the benefits in its economy, which is relevant in the contemporary operating conditions (Akhlaghi et al., 2015). It is rather thermally unstable with a maximum service temperature of approximately 120 °C, above which it becomes hardened and loses elasticity and acquires a high compression set. “Compare static thermal stability of NBR with FKM in TGA, Figure 3.” NBR is also highly susceptible to polar solvents and, therefore, is prone to swelling and degrading when subjected to fuels containing ethanol, like E10 or E85, which reduces the life of seals. On the other hand, FKMs are highly mechanically stable, have low fuel permeability, recover elastically at high temperature and alcohol-based fuels, and have a high service life covering mileage of over 100,000 km (Lee et al., 2022). Compare mechanical properties of NBR and FKM in Table 1. In turn, NBR is suitable for low-stress, low-cost applications, whereas FKMs are needed in high-performance, high-reliability automotive sealing system applications.

Fuel Types and Their Impact

The modern internal combustion engines use a wider variety of fuels, such as gasoline-ethanol mixtures (E5 and E10), high-ethanol fuels (E85), biodiesel, and synthetic fuels (Laskowski & Zimakowska-Laskowska, 2025). Chemical and physical characteristics of each fuel also have different values that affect engine performance and material behavior (Table 2). The ethanol fuels have a lower caloric value compared to gasoline, and thus, they consume more fuel to produce the same amount of energy (Yakın et al., 2022). On the other hand, higher octane rating of ethanol enables some engines to operate at higher compression ratios and even better efficiencies. Although E5 and E10 produce moderate variation of fuel system conditions, E85 produces a significant exposure of polar solvents and water absorption that can aggravate the chemical stress on elastomeric fuel-system components.

Synthetic fuels and biodiesel present a new range of problems. Biodiesel is more lubricious than standard diesel, which may be advantageous in fuel pumping and injecting, but it oxidizes more easily and is susceptible to microbial growth where there is water. These may result in the production of acidic by-products, which hasten the breakdown of elastomers, especially those of low chemical resistance. Biofuels are classified according to their physical state, technology maturity, the generation of feedstock, and the generation of products (Awogbemi et al., 2023). Synthetic fuels, such as e-fuels made of renewable electricity and captured carbon dioxide, are developed to attain similar properties to the conventional hydrocarbons without causing lifecycle greenhouse emissions (US Department of Energy, 2019). Despite being relatively cleaner and relatively chemically inert, they react to certain extent with elastomer alternatives according to certain formulations and additive packages

FKMs, PFAS, and Regulatory Debate

Fluoroelastomers are extremely resistant to alcohol-based fuels, have low permeability, and have a long service life, so they are an essential component in the automotive fuel system (Ameduri and Sawada, 2016). However, their fluorinated structure makes them the object of the extended regulations of PFAS. Even though the FKMs do not have the same mobility, bioavailability, and environmental behavior as low-molecular-weight PFAS, the regulatory definitions are generic. This has brought about confusion among manufacturers and suppliers, where alternative materials and fluorine-reduction strategies are being researched, even though there are no similar non-fluorinated substitutes with the same level of performance.

Strategies to Replace FKMs

Several alternatives are under development that will eliminate or limit the use of FKMs in automobiles. These consist of hydrogenated nitrile butadiene rubber (HNBR, Scheme 1), high-performance thermoplastic elastomers, and silicone elastomers that have improved fuel resistance (Joshi, 2025; Gao et al., 2025). Other mitigation strategies include hybrid seal or multilayer seal construction or surface coating, whereby the traditional elastomers are coupled with thin barrier seals to restrict fuel permeation (Figure 4). The compatibility of elastomers with various fuels indicates that most alternative rubbers (including HNBR and other engineered types) change their mechanical properties significantly under exposure to renewable and blended fuels, which makes it challenging to find alternatives with more or less the same performance as FKM ( Müller et al., 2024). Although they may partially reduce the effects of chemical attack and swelling, none of these solutions can be considered as having the same thermal stability, chemical resistance, and durability as FKMs, especially when exposed to ethanol-rich fuels like E85. Other alternative engineered elastomers such as HNBR, as well as most alternative rubbers, vary their mechanical properties greatly when in contact with renewable and blended fuels, especially when in extended contact with fuels high in ethanol (Conen, Haefele and Dahlmann, 2025).

Road Cars versus Race Cars

The operational and regulatory aspects vary significantly, and this difference in priorities leads to a significant difference between the selection of materials used in road vehicles and race cars. In racing use, performance, high temperature performance, and high temperature performance are crucial factors, and the need to match rapidly evolving fuel compounds is often the reason why FKMs or perfluoro elastomers are continued to be employed despite the cost or regulatory pressure (Katon, 2025). In contrast, road vehicles have to weigh between performance and cost-effectiveness, compliance with regulations, and durability during the long run due to the long service life (Adebowale, 2025). Although race cars still almost entirely use FKMs, the continued development of fluorine-free polymers and multilayer seal technologies implies that road vehicles can use other types of elastomer systems in the future (Mandlekar, Joshi & Butola, 2022; Valentini & Lopez-Manchado, 2020).

Summary

Fluor elastomers have been very important in providing reliability and safety of automotive engines, especially those with high temperatures in the fuel system and hostile fuels (Drobny, 2023). The shift to the use of ethanol-based and synthetic fuels, coupled with stricter regulations on PFAS, has put a lot of pressure on the need to substitute or redesign fluorinated substances. Although the FKMs are still unrivaled in terms of total performance, more so when it comes to accommodating E85 compatibility, regulatory and environmental issues are driving the development of alternative elastomers and hybrid solutions. Even in the near future, it is not probable that FKMs can be fully replaced without performance loss (Puga et al., 2025). Rather, the future of automotive sealants will be characterized by incremental changes in materials and an application-specific approach in both road and race applications. 

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About the author

DongHan Li

DongHan is currently Grade 11 student, studying in Beijing, China. During the course of high school, he has studied the A-level Curriculum in subjects such as physics and chemistry. DongHan has a strong interest in Engineering, especially in Chemical Engineering. Additionally, he has also found himself very intrigued by theories related to Nanotechnology along with fluid dynamics that have facilitated the process of completing this dissertation.

At the same time, DongHan’s interest in motorsports (Grand Touring 3 race cars ) has helped develop the general aim of this dissertation. As motorsports develop continuously over time, it is very promising and exciting to dig into and challenge the theories that already exist, hoping to offer alternative solutions to existing engineering challenges.

The post Fluoroelastomer Sealants and their Alternatives in Automotive Engines Supplied with E-fuels appeared first on Exploratio Journal.

Abstract

Accurate crop yield forecasting plays a critical role in ensuring national food security, guiding agricultural policy, and informing market strategies. India, with its vast agro-ecological diversity and a population exceeding 1.4 billion, faces unique challenges in aligning production with demand. This research presents a comprehensive multi-model machine learning (ML) framework for predicting crop yields across 30 Indian states, explicitly integrating population density and urban–rural composition as demand-related features. Eleven algorithms are evaluated, including Random Forest, XGBoost, LightGBM, CatBoost, Gradient Boosting, Bagging, AdaBoost, Decision Tree, Extra Trees, K-Nearest Neighbors, and Multi-layer Perceptron. The dataset spans 1997–2020 with 19,689 records, incorporating demographic, climatic, and agronomic variables. Results show ensemble methods outperform individual models, with Random Forest achieving the highest performance (R2 = 0.9803, RMSE = 125.79), followed by Bagging (R2 = 0.9793) and XGBoost (R2 = 0.9766). Population features contributed a modest yet consistent improvement of 0.6% in predictive accuracy, with market accessibility and urban–rural ratio being the most influential. LightGBM exhibited the greatest stability (CV = 0.9679 ± 0.0131), while Random Forest offered the best trade-off between interpretability and accuracy. This study highlights the importance of integrating both supply-and demand-side variables for robust agricultural planning and improved food security.

1 Introduction

Global food systems face increasing pressure from climate change, population growth, and resource constraints. For India, agriculture supports the livelihoods of over half the population and contributes significantly to GDP [7]. Accurate yield forecasting is essential to ensure supply meets demand, optimise resource allocation, and stabilise markets. Traditional statistical models, such as regression and time-series approaches, often fail to capture the non-linear, high-dimensional interactions in agricultural data [5]. ML techniques can model these complex relationships, offering improved accuracy [10]. Most prior Indian studies focus on supply-side factors like rainfall, fertiliser use, and cropping patterns, neglecting demand-side influences such as population density and market accessibility. This study bridges that gap by evaluating 11 ML algorithms while integrating demographic features, aiming for balanced supply-demand yield forecasts.

The research addresses several critical gaps in current agricultural forecasting literature. First, while machine learning has been applied to crop yield prediction globally, comprehensive comparative studies in the Indian context remain limited. Second, the integration of demographic and socio-economic factors with traditional agronomic variables represents a novel approach that captures the complex interplay between agricultural production and human settlement patterns. Third, the evaluation of state-of-the-art gradient boosting algorithms (XGBoost, LightGBM, CatBoost) alongside traditional ensemble methods provides insights into the most effective approaches for Indian agricultural data.

The significance of this research extends beyond academic contribution to practical agricultural planning. With India’s population projected to reach 1.5 billion by 2030, understanding how demographic differences — such as variations in population density, market accessibility, and urban–rural composition — influence agricultural demand and production patterns becomes crucial for food security planning. The integration of population density and urbanization patterns into yield forecasting models enables policymakers to anticipate how these differences affect agricultural demand and adjust production strategies accordingly.

2 Literature Review

2.1 Machine Learning in Agricultural Forecasting

Machine learning methods, particularly tree-based ensembles and neural networks, have shown strong predictive capability in agricultural forecasting [11]. LSTM networks excel in modelling temporal dependencies in sequential agricultural data [9], while hybrid models combining process-based and ML approaches improve generalisability.

The evolution of machine learning in agricultural forecasting has followed several distinct phases. Early applications focused on simple regression models and decision trees, which provided interpretable results but limited predictive accuracy. The introduction of ensemble methods, particularly Random Forest, marked a significant advancement by combining multiple decision trees to reduce variance and improve generalization. More recently, gradient boosting algorithms have demonstrated superior performance in various agricultural applications, with XGBoost, LightGBM, and CatBoost emerging as state-of-the-art solutions.

Recent studies have demonstrated the effectiveness of deep learning approaches in agricultural forecasting. Convolutional Neural Networks (CNNs) have been successfully applied to satellite imagery analysis for crop monitoring, while Recurrent Neural Networks (RNNs) and Long Short-Term Memory (LSTM) networks have shown promise in capturing temporal dependencies in yield data. However, these approaches often require large datasets and extensive computational resources, making them less suitable for regions with limited data availability. Additionally, deep learning models are generally less interpretable and explainable compared to traditional machine learning methods, which poses challenges for stakeholder trust and regulatory compliance in agricultural policy applications

2.2 Ensemble and Gradient Boosting Methods

Ensemble methods aggregate predictions from multiple models to improve accuracy and stability. RF, XGB, Light GBM, and CB have proven effective in agricultural applications, handling non-linearities, noise, and high-dimensional datasets [1, 2, 6, 8].

The theoretical foundation of ensemble methods lies in the principle of combining multiple weak learners to create a strong learner. This approach addresses several limitations of individual models, including overfitting, sensitivity to noise, and limited generalization capability. Random Forest, for instance, constructs multiple decision trees on bootstrapped samples of the training data, reducing variance through averaging while maintaining low bias.

Gradient boosting represents a more sophisticated ensemble approach that builds models sequentially, with each subsequent model focusing on the errors of its predecessors. XGBoost extends this concept with advanced regularization techniques, including L1 and L2 regularization, which help prevent overfitting and improve generalization. LightGBM optimizes the training process through leaf-wise tree growth and histogram based algorithms, making it particularly suitable for large datasets.

CatBoost introduces several innovations, including ordered boosting and native handling of categorical features, which addresses common challenges in agricultural data preprocessing. The algorithm’s robust default settings and reduced sensitivity to hyperparameters make it particularly valuable for practitioners with limited tuning expertise.

2.3 Population Density and Agricultural Productivity

Population density influences agricultural productivity through intensification, infrastructure development, and market access [5]. In India, urban proximity affects crop choice and resource allocation [3].

The relationship between population density and agricultural productivity operates through multiple interconnected mechanisms. First, higher population density typically leads to increased demand for agricultural products, driving intensification of production through improved technology adoption, better irrigation systems, and more efficient resource utilization. Second, population density influences infrastructure development, with more densely populated areas typically having better access to agricultural inputs, markets, and extension services.

Urbanization patterns further complicate this relationship. As rural areas become more urbanized, agricultural land use patterns shift, often leading to more intensive production on remaining agricultural land. Additionally, urban proximity affects crop choice, with farmers near urban centers often shifting toward high-value crops that can be sold in urban markets. This phenomenon, known as the “urbanization effect,” has been documented in various developing countries and represents an important consideration for agricultural planning.

Market accessibility, closely related to population density and urbanization, plays a crucial role in determining agricultural productivity. Areas with better market access typically have higher agricultural productivity due to improved input availability, better price information, and reduced transaction costs. The integration of market accessibility metrics into yield forecasting models represents a significant advancement in capturing the full spectrum of factors influencing agricultural productivity.

2.4 Indian Agricultural Context and Challenges

India’s agricultural sector faces unique challenges that make accurate yield forecasting particularly important. The country’s diverse agro-climatic zones, ranging from tropical to temperate regions, create significant variations in crop suitability and productivity. Additionally, India’s agricultural system is characterized by small landholdings, with approximately 86% of farmers operating on less than 2 hectares of land. This fragmentation presents challenges for data collection and analysis, as well as for the implementation of forecasting-based policies.

Climate change poses additional challenges for Indian agriculture, with increasing variability in rainfall patterns, rising temperatures, and more frequent extreme weather events. These changes affect both crop yields and the reliability of historical data for forecasting purposes. The integration of climate variables into yield forecasting models becomes increasingly important as these patterns continue to evolve.

2.5 Related Work Summary Table

These studies were selected based on their direct relevance to our research objectives and methodological approach. Van [10] and Ghar et al. [4] influenced our decision to conduct a comprehensive multi-algorithm comparison, while de et al. [3] specifically guided our 4 integration of demographic features into crop yield forecasting models for the Indian context. The foundational algorithm papers [1, 2, 6, 8] shaped our understanding of ensemble methods and guided our hyperparameter tuning strategies. Sharma et al.’s work [9] on Indian agricultural data provided important benchmarks for expected performance levels and demonstrated the effectiveness of advanced ML techniques in the Indian agricultural context.

3 Methodology

3.1 Data Provenance and Collection

Data were sourced from the Directorate of Economics and Statistics, Ministry of Agriculture and Farmers’ Welfare, Government of India, supplemented with Census demographic data, covering 1997–2020. The primary dataset contains comprehensive information on crop production, including yield, area under cultivation, fertilizer and pesticide usage, and rainfall patterns across 30 Indian states and union territories.

The demographic data was obtained from the Indian Census conducted in 2001, 2011, and projections for other years. Population density calculations were based on total population divided by geographical area, with urban-rural ratios derived from census definitions of urban areas. The integration of these datasets required careful temporal alignment and spatial matching to ensure consistency across different data sources.

Additional data sources included the Indian Meteorological Department for rainfall data, the Department of Fertilizers for input usage statistics, and various state agricultural departments for crop-specific information. The comprehensive nature of the dataset, spanning 24 years and covering multiple dimensions of agricultural production, provides a robust foundation for machine learning analysis.

3.2 Data Preprocessing and Quality Assurance

Cleaning included duplicate removal, unit standardisation, and median imputation for missing numeric values. Missing data constituted approximately 8.3% of the total dataset (1,635 out of 19,689 records), distributed across multiple variables with rainfall data showing the highest missing rate (4.2%) followed by fertilizer usage (2.8%). Missing data patterns were analyzed and determined to be missing at random (MAR) based on Little’s MCAR test (p < 0.001), indicating that missingness was related to observable variables rather than the missing values themselves. Outliers were addressed using IQR-based thresholds, with approximately 3.7% of observations flagged as potential outliers. The preprocessing pipeline was designed to maintain data integrity while ensuring compatibility with machine learning algorithms.

Duplicate removal was performed using multiple criteria, including crop type, state, year, season, and area under cultivation. Unit standardization involved converting all measurements to consistent units (tons for production, hectares for area, millimeters for rainfall). Missing value imputation was performed using median values within crop-state-season combinations to preserve the natural variation in agricultural data.

Outlier detection and treatment followed a systematic approach. Values beyond 1.5 times the interquartile range were flagged as potential outliers. Outliers representing legitimate extreme values (such as exceptional yields due to favorable weather conditions) were retained based on agricultural domain knowledge and data distribution analysis. Otherwise, they were capped at the 95th percentile to prevent undue influence on model training.

3.3 Feature Engineering and Selection

Label encoding was applied to categorical features. Derived metrics included fertiliser-per-area and pesticide-per-area. Market accessibility was derived from urban–rural ratios. The feature engineering process was guided by domain knowledge and statistical analysis to ensure relevance and predictive power.

Categorical variables, including crop type, season, state, and population category, were encoded using label encoding. While one-hot encoding could provide more detailed representation, label encoding was chosen for computational efficiency and to maintain the ordinal relationships present in some categorical variables (such as population density categories).

Derived features were created to capture important ratios and interactions. Fertilizer-per-area and pesticide-per-area ratios provide measures of input intensity that may be more predictive than absolute usage values. Market accessibility was calculated as a function of urban-rural ratio, reflecting the hypothesis that more urbanized areas have better market access and infrastructure.

Feature selection was performed using both statistical methods and domain expertise. Correlation analysis identified highly correlated features that could lead to multicollinearity, while feature importance analysis from preliminary Random Forest models guided the selection of the most predictive variables. The final feature set comprised 13 variables, balancing predictive power with computational efficiency.

3.4 Model Implementation and Architecture

Implemented algorithms: RF, Bagging, AdaBoost, Extra Trees, XGB, LightGBM, CB, GBM, Decision Tree, KNN, MLP, using scikit-learn, XGBoost, LightGBM, and CatBoost libraries. Each algorithm was implemented with careful attention to parameter settings and computational requirements.

Random Forest was implemented with 200 estimators, maximum depth of 15, and minimum samples split of 5. These parameters were chosen based on preliminary experimentation and literature recommendations for agricultural datasets. The algorithm’s ability to handle mixed data types and provide feature importance rankings made it particularly suitable for this application.

Gradient boosting variants (XGBoost, LightGBM, CatBoost) were implemented with 200 estimators, maximum depth of 6, and learning rate of 0.1. These conservative parameter settings were chosen to prevent overfitting while maintaining computational efficiency. The algorithms’ advanced regularization techniques and optimization algorithms provide superior performance for complex datasets.

Traditional machine learning algorithms (Decision Tree, K-Nearest Neighbors, Multilayer Perceptron) were implemented as baseline models for comparison. These algorithms provide important benchmarks for evaluating the effectiveness of ensemble methods and help identify the specific advantages of more sophisticated approaches.

3.5 Hyperparameter Tuning Strategy and Optimization

Random search with five-fold CV optimised hyperparameters (tree depth, estimators, learning rate). The tuning process was designed to balance exploration of the parameter space with computational efficiency, ensuring robust model performance without excessive computational cost.

The hyperparameter search space was defined based on literature recommendations and preliminary experimentation. For tree-based models, key parameters included the number of estimators, maximum depth, minimum samples split, and minimum samples leaf. For gradient boosting models, learning rate, subsample ratio, and column sampling ratios were also considered.

Cross-validation was performed using stratified sampling to ensure representative distribution of crop types and states across folds. This approach provides more reliable estimates of model performance and helps identify models that generalize well to unseen data.

The optimization objective was to maximize R-squared score while maintaining reasonable computational requirements. Models that showed signs of overfitting (high training performance but low validation performance) were penalized in the selection process.

3.6 Evaluation Protocol and Performance Metrics

Train-test split (80-20) with stratified sampling. Metrics: R2, RMSE, MAE, and bias (mean prediction error). CV assessed stability. The evaluation protocol was designed to provide comprehensive assessment of model performance across multiple dimensions, including accuracy, precision, and systematic error patterns.

The train-test split was performed using stratified sampling to ensure representative distribution of crop types and states across both sets. This approach is particularly important for agricultural data, where different crops and regions may have significantly different yield patterns and variability.

Performance metrics were chosen to capture different aspects of model performance. R-squared measures the proportion of variance explained by the model, providing an overall assessment of fit quality. RMSE penalizes larger errors more heavily, making it sensitive to outliers and extreme values. MAE provides a straightforward interpretation of average prediction error, useful for practical applications.

Cross-validation was performed using 5-fold stratified sampling to assess model stability and generalization capability. The standard deviation of cross-validation scores provides important information about model reliability and suitability for production deployment.

4 Results

4.1 Descriptive Statistics and Data Characteristics

Yield values ranged from below 1 t/ha to above 10 t/ha. Input usage varied widely by crop and state. The dataset exhibits significant variation across multiple dimensions, reflecting the diverse nature of Indian agriculture.

The yield distribution shows considerable skewness, with most observations concentrated in the lower range and fewer observations at higher yield levels. This pattern is typical of agricultural data and presents challenges for modeling, as models must accurately predict both typical and extreme yield values.

Input usage patterns reveal significant variation across crops and regions. Fertilizer usage ranges from minimal application in subsistence farming systems to intensive application in commercial agriculture. Pesticide usage shows similar variation, with some crops and regions showing minimal usage while others demonstrate intensive pest management practices.

Population density shows extreme variation across states, from sparsely populated mountainous regions to densely populated urban centers. This variation provides valuable information for understanding the relationship between demographic factors and agricultural productivity.

4.2 Comparative Model Performance Analysis

The comprehensive evaluation of 11 machine learning models reveals significant performance variations across different algorithms. Table 2 presents the complete performance ranking:

Ensemble methods consistently outperform individual models, demonstrating the value of combining multiple decision strategies for agricultural forecasting. Random Forest achieved the highest performance with R² of 0.9803 and RMSE of 125.79, representing the best balance of accuracy and interpretability. The algorithm’s ability to handle high-dimensional data and capture complex feature interactions makes it particularly suitable for agricultural forecasting where multiple factors influence yield simultaneously.

Bagging follows closely with R² of 0.9793 and RMSE of 128.68, demonstrating the effectiveness of bootstrap aggregation in reducing variance. The algorithm’s parallel training capability and stability make it suitable for production environments where consistent performance is crucial.

XGBoost achieves excellent performance with R² of 0.9766 and RMSE of 136.79, showcasing the power of advanced gradient boosting techniques. The algorithm’s built-in regularization and optimization algorithms provide superior performance for complex datasets, though at the cost of increased computational complexity.

4.3 Analysis of High-Performing Models and Algorithm Comparison

RF achieved the highest accuracy; Bagging was close, XGB balanced performance and computational efficiency. The analysis reveals important trade-offs between different algorithms and provides insights into their suitability for various applications.

Random Forest’s superior performance can be attributed to several factors. The algorithm’s ability to handle mixed data types, capture non-linear relationships, and provide robust predictions makes it particularly suitable for agricultural data. Additionally, Random Forest’s feature importance analysis provides valuable insights into the factors driving agricultural productivity.

Bagging’s strong performance demonstrates the effectiveness of bootstrap aggregation in reducing variance and improving generalization. The algorithm’s parallel training capability and stability make it suitable for production environments where consistent performance is crucial.

XGBoost’s performance highlights the advantages of advanced gradient boosting techniques. The algorithm’s built-in regularization, early stopping, and optimization algorithms provide superior performance for complex datasets. However, the increased computational complexity and sensitivity to hyperparameters may limit its suitability for some applications.

4.4 Model Stability and Cross-Validation Analysis

Light GBM had the lowest CV variance, indicating consistent performance. Cross-validation analysis reveals important insights into model stability and generalization capability, providing guidance for model selection in production environments.

LightGBM demonstrates the highest stability with CV mean of 0.9679 and standard deviation of 0.0131, indicating consistent performance across different data subsets. This high stability makes LightGBM particularly suitable for production environments where consistent performance is crucial.

Random Forest shows good stability with CV mean of 0.9563 and standard deviation of 0.0447, providing a good balance between performance and reliability. The algorithm’s robustness to outliers and noise in agricultural data contributes to its consistent performance.

Decision Tree and K-Nearest Neighbors show the lowest stability with high standard deviations, indicating sensitivity to data variations and potential overfitting issues. These algorithms may not be suitable for agricultural forecasting without extensive regularization and feature selection.

4.5 Forecasting Bias Patterns and Error Analysis

Detailed bias analysis reveals systematic patterns in model predictions that provide important insights into model behavior and potential areas for improvement. Figure 1 provides comprehensive diagnostic plots for the top-performing models, while Table 3 presents the bias analysis for the top 5 models:

Figure 1: Model diagnostic plots showing residual analysis, prediction vs actual comparisons, and error distributions for the top-performing models. These plots reveal systematic bias patterns, prediction accuracy across different yield ranges, and model reliability characteristics.

All top models show slight underforecasting tendencies, indicating conservative prediction behavior. Random Forest shows minimal systematic bias with mean error of 0.171 units, indicating well-calibrated predictions. The algorithm’s robust nature and ability to handle outliers contribute to its balanced performance across different yield ranges.

Bagging and XGBoost also show minimal systematic bias, with mean errors of 0.335 and 0.125 units respectively. These algorithms’ ensemble nature and advanced regularization techniques help maintain balanced predictions. CatBoost and LightGBM show some systematic patterns in residuals, particularly underestimating high yields and overestimating low yields. These patterns suggest that these algorithms may benefit from additional tuning or feature engineering to address the bias. The different patterns observed in the diagnostic plots reflect the algorithms’ distinct approaches to handling data complexity: the top three models (Random Forest, Bagging, XGBoost) show more uniform scatter patterns with points closely aligned to the diagonal line, indicating better calibrated predictions. In contrast, CatBoost and LightGBM exhibit more curved or S-shaped patterns in their residual plots, suggesting systematic prediction biases that vary across different yield ranges, likely due to their sequential boosting mechanisms being more sensitive to extreme values in the agricultural dataset.

4.6 Population Feature Impact and Demographic Analysis

Demographic features improved accuracy by 0.6%, supporting their inclusion. The integration of population features provides valuable insights into demand-side factors affecting agricultural productivity and demonstrates the value of comprehensive feature engineering. Table 4 presents the detailed impact of population-related features:

Crop type emerges as the dominant predictor with 84.6% importance, followed by state location (9.8%) and cultivation area (1.4%). Population-related features collectively contribute 0.6% to overall model performance, with market accessibility and urban-rural ratio being the most influential demand factors. This modest but consistent improvement demonstrates the value of incorporating demographic information into agricultural forecasting models.

Market accessibility and urban-rural ratio each contribute 0.30% to prediction accuracy, suggesting that urbanization patterns and market infrastructure significantly influence agricultural productivity. These features likely capture the effects of improved input availability, technology adoption, and market access in urbanized areas.

Population category shows minimal contribution (0.02%), suggesting that absolute population density is less important than urbanization patterns and market accessibility. This finding indicates that the quality of infrastructure and market access is more important than the sheer number of people in determining agricultural productivity.

5 Discussion

5.1 Operational Deployment Feasibility and Implementation

RF and LightGBM can be deployed in agricultural dashboard for near real-time forecasting. The research findings provide important guidance for the operational deployment of machine learning models in agricultural forecasting systems.

Random Forest’s combination of high performance and interpretability makes it particularly suitable for operational deployment. The algorithm’s feature importance analysis provides valuable insights for stakeholders, while its robust performance ensures reliable predictions across different conditions.

LightGBM’s high stability and computational efficiency make it suitable for real-time forecasting applications. The algorithm’s fast training and prediction times enable near-real-time updates, while its consistent performance ensures reliable predictions.

The deployment of these models in agricultural dashboards would provide policymakers, farmers, and market participants with timely and accurate yield forecasts, supporting better decision-making and resource allocation.

5.2 Model Interpretability Considerations and Stakeholder Trust

Tree-based ensembles support feature importance and partial dependence plots for policy transparency. The interpretability of machine learning models is crucial for gaining stakeholdertrustandensuringwidespreadadoptionofforecasting-baseddecision-making.

Random Forest’s feature importance analysis provides clear insights into the factors driving agricultural productivity, supporting evidence-based policy development. The algorithm’s decision tree structure enables the creation of partial dependence plots that show how individual features influence predictions.

The transparency provided by these interpretability tools is particularly important in agricultural contexts, where stakeholders may have limited technical expertise but require confidence in forecasting results. Clear explanations of model predictions and the factors influencing them support better decision-making and policy development.

5.3 Limitations and Assumptions of Current Approach

The current analysis is subject to several limitations that should be considered when interpreting the results and planning future research. These limitations provide important context for understanding the scope and applicability of the current findings.

The models assume that the relationships between features and yields remain constant over time, which may not hold true in the face of significant changes in agricultural practices, climate conditions, or policy environments. This assumption limits the long-term applicability of the models and suggests the need for regular retraining and validation.

The population density data is estimated based on historical trends and may not capture sudden demographic differences or migration patterns. This limitation affects the accuracy of population-related features and suggests the need for more frequent updates of demographic data.

The analysis focuses on Indian agricultural data, limiting the generalizability of the results to other agricultural contexts. While the methodologies and algorithms may be applicable elsewhere, the specific findings and parameter settings may not transfer directly to other regions or agricultural systems.

The dataset lacks crop quality indicators such as protein content, moisture levels, and post-harvest characteristics, which are important factors in determining the economic value of agricultural output. The models focus solely on yield quantity without considering quality attributes that significantly influence market prices and food security outcomes. This limitation affects the comprehensive assessment of agricultural productivity and suggests the need for future research incorporating quality metrics alongside yield predictions.

5.4 Computational Considerations and Scalability

The computational requirements of different algorithms present important considerations for operational deployment and scalability. These considerations affect the choice of algorithms for different applications and the infrastructure requirements for deployment.

Random Forest and Bagging algorithms can be parallelized effectively, making them suitable for deployment on multi-core systems. These algorithms’ parallel nature enables efficient training and prediction on large datasets, supporting real-time forecasting applications.

Gradient boosting algorithms (XGBoost, LightGBM, CatBoost) require more computational resources but provide superior performance. The choice between these algorithms and simpler ensemble methods depends on the specific requirements for accuracy, speed, and computational resources.

The deployment of these models in production environments requires careful consideration of computational infrastructure, including processing power, memory requirements, and storage capacity. These requirements affect the cost and feasibility of operational deployment.

6 Conclusion

This study benchmarks eleven ML algorithms for crop yield forecasting in India, demonstrating ensemble superiority and the benefits of including demographic features. RF was the top performer; LightGBM was the most stable. The comprehensive evaluation provides important insights into the effectiveness of different machine learning approaches for agricultural forecasting.

The superior performance of ensemble methods, particularly Random Forest, demonstrates the value of combining multiple decision strategies in agricultural forecasting. The significant performance gap between ensemble methods and individual models highlights the importance of sophisticated modeling approaches for complex agricultural data.

The integration of population features provides consistent improvements in forecasting accuracy, supporting the inclusion of demographic factors in agricultural forecasting models. While the improvement is modest, it represents a meaningful enhancement that contributes to better agricultural planning and policy development.

The research contributes to improved agricultural forecasting by demonstrating the value of comprehensive model evaluation and ensemble methods in agricultural prediction. The findings support the development of multi-model forecasting systems that can provide more robust and reliable predictions for agricultural planning and policy development.

7 Future Work and Research Directions

Future research should explore crop-specific models, integration of real-time climate and remote sensing data, soil index integration, explainable AI for stakeholder trust, and scenario modelling for climate impact assessment. These directions build on the current findings and address important gaps in agricultural forecasting research.

The development of crop-specific models could significantly improve forecasting accuracy by capturing the unique characteristics and requirements of different crops. The high importance of crop type in the current models suggests that specialized approaches for different crop categories could provide substantial improvements in prediction accuracy.

The integration of real-time climate data and remote sensing information could enhance the models’ ability to capture environmental factors affecting agricultural productivity. These data sources provide more timely and detailed information about growing conditions, potentially improving short-term forecasting accuracy.

The development of explainable AI techniques, including SHAP values and partial dependence plots, could improve stakeholder trust and support better decision-making. These techniques provide clear explanations of model predictions and the factors influencing them, supporting transparency and accountability in agricultural forecasting.

Scenario modeling for climate impact assessment could help policymakers understand the potential effects of climate change on agricultural productivity and develop appropriate adaptation strategies. These models could incorporate various climate change scenarios and assess their impact on crop yields and food security.

References

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About the author

Advika Lakshman

Advika is currently pursuing Artificial Intelligence and Data Science at Shiv Nadar University, Chennai. Her academic interests span across machine learning, deep learning, natural language processing, big data analytics, and speech technology. She has worked on diverse projects such as early sepsis prediction using clinical time-series data, sketch-to-face translation with DCGANs, geophysical data inpainting with Masked Autoencoders, and salary prediction using ensemble models. Advika has also interned at the National University of Singapore (Big Data, Deep Learning, Generative AI) and the Spring Lab at IIT Madras, where she developed ASR pipelines using HuBERT and ESPnet for multilingual speech data.

Outside academics, Advika is a professional Bharatanatyam dancer, with over 12 years of training and multiple state and national-level awards, including recognitions from Doordarshan. She also actively contributes to university events and communications through marketing and public relations initiatives.

The post Comprehensive Crop Yield Forecasting in India: A Multi-Model Machine Learning Approach with Population Density Integration for Agricultural Planning appeared first on Exploratio Journal.

Abstract

The long-running socio-economic crisis in Venezuela has severely damaged public healthcare systems, which now face persistent shortages and restricted service availability. This research investigates Venezuelan patients’ healthcare challenges and their strategies for managing these obstacles, with particular attention to gender-specific barriers in service accessibility. The researcher conducted semi-structured interviews with 13 Venezuelan adults from different regions between July 14 and July 16, 2025. Interviews were conducted in Spanish through WhatsApp text and voice notes, then transcribed, translated into English, and pseudonymized. Inductive thematic analysis identified recurring patterns, while frequency counts determined the relative prevalence of each theme. Seven main themes emerged: medication shortages, poor public hospital facilities, insufficient specialist care, reliance on private healthcare services or HCM insurance, non-traditional medical approaches and foreign medication acquisition, preventive self-care measures, and community-based fundraising and support systems. Women described additional challenges accessing reproductive healthcare, managing chronic illnesses, and obtaining medical treatment outside their local areas. Current patient adaptation strategies—including preventive actions, unofficial support networks, and cross-border medication procurement—remain unstable and create unequal outcomes that affect women most severely. Policy priorities should focus on reliable medication supply chains, protected crossborder medical a

Keywords: Venezuela; healthcare access; qualitative interviews; women’s health; resilience; health systems.

1. Introduction

The public health system of Venezuela which used to rank as one of the best in Latin America has experienced a significant decline because of ongoing political instability, economic decline and hyperinflation (World Health Organization [WHO] 2023; Ortega et al. 2020). The healthcare facilities in Venezuela face ongoing problems with medicine, supply shortages, equipment breakdowns and massive healthcare worker departures to find better employment opportunities abroad (Doocy et al. 2019; Pan American Health Organization [PAHO] 2023). The healthcare system operates at reduced capacity because of these disruptions which force wealthier patients to seek private care or foreign medical services while low-income patients receive inadequate treatment (Rodríguez 2020; Hetland 2021).

The research examines how typical Venezuelans handle the structural failures that affect their healthcare system. The research investigates two main questions which are (1) What obstacles do patients face when they try to receive medical care in their daily lives? and (2) What strategies do patients use to overcome these barriers and how do women patients specifically handle these challenges? The research uses patient testimonies from 2025 to show the actual experiences that exist beyond official reports about system failures and it also provides a patient-centered perspective through its focus on their coping mechanisms and emotional responses which enhance existing quantitative and infrastructure-based studies of Venezuela’s healthcare emergency (Doocy et al. 2017; PAHO 2023).

This research has shown that hospitals face medicine shortages, stockouts and administrative breakdowns but it has not fully explored how patients make decisions when resources are scarce. The research connects these findings by showing how Venezuelans handle broken healthcare systems and how gender influences their treatment routes, women experience unique barriers to healthcare access because of their reproductive needs and caregiving duties. Limited mobility actually worsens their unequal healthcare opportunities. The analysis of gendered healthcare system performance under extreme economic conditions provides valuable knowledge about system breakdowns.

Research Questions:

1. What barriers do patients in Venezuela encounter in everyday efforts to obtain healthcare?
2. How do patients, particularly women, adapt to or circumvent these barriers?

2. Literature Review

Multiple research studies from national and international experts have documented the complete breakdown of Venezuela’s healthcare system. Multiple research studies confirm the severe state of infrastructure deterioration through reports about continuous medicine shortages, equipment breakdowns and even healthcare worker departures (Doocy et al., 2019; Ortega et al., 2020; PAHO, 2023; WHO, 2023). The public healthcare system which used to serve as a regional benchmark now operates with permanent shortages that force hospitals to stop vital services while patients must bring their own medical supplies. The healthcare system shows that major urban hospitals continue to operate at reduced capacity but peripheral medical facilities have lost almost all of their operational ability which results in major disparities between urban and rural areas as well as between different social classes (Rodríguez, 2020; Hetland, 2021).

Research on healthcare system collapse has led experts to study how patients experience medical care delivery in deteriorating facilities. The combination of unstable supply chains and currency fluctuations results in unpredictable access to vital medications according to Doocy et al. (2017) and Hetland (2021). The research community agrees that patients directly experience the consequences from both international sanctions and domestic governance problems although they disagree about which factor has the most impact. Households actually manage medicine shortages through three main strategies which include buying from informal markets and using remittances and implementing medicine rationing (Freitez, 2022; International Organization for Migration [IOM], 2022). The survival systems that Venezuelans create operate independently from official healthcare systems through parallel networks or function completely outside of them.

The current research on healthcare system failures provides essential information about large-scale breakdowns yet fails to examine how people and their families make independent decisions when facing scarcity at the individual level. Research using qualitative and feminist methods demonstrates that healthcare emergencies reveal existing gender-based social inequalities (Melo et al., 2023; Rueda-Salazar & García, 2024). The healthcare challenges Venezuelan women encounter stem from multiple factors which include reproductive care restrictions, family care duties as well as limited freedom of movement. The combination of financial constraints and shut-down specialized maternal facilities forces women to handle their pregnancies and also chronic diseases and family health crises without institutional backing. Research conducted in neighboring countries indicates that Venezuelan migrant women encounter equivalent healthcare obstacles because of their immigration status and social discrimination which demonstrates that gender-based healthcare disparities exist across international borders (Melo et al., 2023; Rueda-Salazar & García, 2024).

Academic researchers now employ resilience frameworks to study how people and their communities handle extended crisis situations. According to Norris et al. (2008) community resilience emerges from social networks and economic resources and information access which enable stress absorption. The survival of Venezuelans depends on individual resourcefulness as well as the support systems which include family networks and community structures and international connections. The research on Venezuelan families shows that they use remittances together with informal support networks and preventive self-care techniques to create their survival strategies (Freitez, 2022). The distribution of these survival strategies remains unequal due to people who possess foreign currency and have access to border travel and stable communication networks succeed in adapting better than those who do not.

Research on Venezuelan healthcare infrastructure deterioration has received extensive study but patient decision-making within Venezuela actually remains highly understudied. Most of the research found focuses on institutional breakdowns instead of showing how patients experience these breakdowns in their daily lives. The research combines patient testimonies with structural evaluations to show how women and other individuals handle healthcare access in a system that has stopped operating effectively.

3. Methods

This study used qualitative methods to explore Venezuelan patients’ experiences of healthcare access and adaptation under system collapse. Semi-structured, one-on-one interviews were chosen to capture the nuance of personal narratives and to be able to allow participants to describe their healthcare decisions in their own personal words.

3.1 Participants and Recruitment

The research included thirteen women aged 17 to 65 who participated in individual interview sessions. The researcher picked participants who lived in Venezuelan cities and mainly surrounding areas including Caracas, Guarenas, Maracay, Ciudad Bolívar and Valles del Tuy. The researcher was able to use trusted local contacts to find participants in June 2025 before they expanded the participant pool through WhatsApp using snowball sampling techniques; this method was selected because it helped achieve both geographic and socioeconomic diversity while safeguarding participants from political dangers in the unstable setting.

The study participants were all Venezuelan residents who received healthcare from the national system during the previous years. While the study excluded participants who lacked capacity to give consent or lived outside Venezuela. The study selected women as participants because their input was necessary for conducting gender-based research.

The three-day interview schedule from July 14 to July 16 2025 worked with participants’ work commitments and protected them from dangerous extended online sessions because of unreliable power supply. The researcher understands that snowball sampling could have brought social-network bias because people with restricted smartphone access became less probable to join the study. The Study Limitations section provides further information about these methodological restrictions.

3.2 Data Collection

The research team conducted Spanish-language interviews through WhatsApp text and voice calls from July 14 to July 16 2025 with each session lasting between 30 to 55 minutes. The platform enabled participants to interact at their own pace while ensuring their safety through asynchronous communication. The interview guide asked participants to answer open-ended questions about their care-seeking actions, their experiences with medication access, healthcare facilities, specialist availability and their financial approaches and their coping strategies.

The researcher conducted a pilot test of the interview guide with two Venezuelan contacts to verify both cultural understanding and language precision. The participants gave their consent through WhatsApp messages of all interviews while bilingual reviewers checked the accuracy of the English translation to preserve the original meaning which confirmed their willingness to participate and their ability to leave the study anytime. The transcription researcher substituted all personal information with pseudonyms to protect participant confidentiality.

3.3 Ethical Considerations

The research followed all necessary ethical guidelines for qualitative studies with low risk while the participants received information about digital communication privacy risks in Venezuela while being told to keep hospital names and official identities undisclosed. The researcher stored all data through encrypted files which required password protection and immediately removed identifying information from translated transcripts. The researcher also did not offer any payment to participants because they wanted to protect them from external influences in a region with limited resources.

3.4 Data Analysis

The researcher conducted inductive thematic analysis (Braun & Clarke, 2006) to find recurring patterns and categories. The researcher performed multiple readings of transcripts for familiarization before using line-by-line coding to produce initial codes which later became broader thematic categories. The researcher examined candidate themes throughout the complete dataset to develop them into final themes while creating analytical memos for support.

The researcher documented all coding choices in a very detailed audit trail while performing negative-case searches and by also maintaining reflexive notes about positionality and translation decisions.The study’s exploratory nature required a single coder to analyze data while reflexive documentation replaced traditional intercoder reliability assessment.

4. Results

The research study found seven core themes which demonstrate how Venezuelan patients handle their healthcare needs in a system that lacks stability and has broken down into seven separate parts. The themes show how patients experience multiple forms of scarcity, adaptation and inequality which demonstrate both the complete breakdown of official healthcare services as well as the development of survival methods outside formal care. The following section presents an overview of theme distribution and relationships through Figures 1 and 2 before moving to the detailed analysis.

Figure 1 presents a frequency chart showing how often each of the seven themes appeared across the thirteen interviews. All participants discussed medication unavailability but specialist shortages and substandard public hospital conditions were mentioned by most many participants. The frequency chart in Figure 1. The themes of preventive health behaviors and private insurance use emerged less often but generated intense emotional as well as social responses. The visual data shows that scarcity-related problems took center stage in participant experiences while serving as the foundation for their coping mechanisms.

The binary-coded matrix in Figure 2 shows which seven key themes each of the thirteen participants discussed during their interviews. The left column contains participant identification numbers which match the thematic categories found in the right columns. The maroon filled cells in the matrix indicate participants discussed specific themes while yellow cells show their absence. The visualization shows that participants experienced both common barriers like medication shortages and less common challenges related to community fundraising and also preventive self-care. The chart demonstrates how different participants experienced various structural barriers at different levels which reveals how coping strategies spread unevenly throughout the healthcare system collapse.

4.1 Theme 1→Medication Unavailability

The thirteen participants in the study all described their ongoing struggles to get necessary medications through Venezuela’s public healthcare system. The participants identified medication shortages as their main obstacles which made it difficult to treat hypertension, diabetes, Parkinson’s disease and even asthma.

The woman from Nueva Casarapa explained that her friend received no medical supplies during her pneumonia hospitalization because her family needed to purchase all necessary items including gloves, she stated “the experience made me lose faith in the public healthcare system.” The patient population learned to accept that hospitals would only offer physical care facilities.

A healthcare provider at Guarenas Hospital stated that medications remain the hospital’s top priority but the supplies never reach on schedule. The resident of Ciudad Bolívar described how his grandmother suffered from severe leg pain because the hospital lacked any pain medication. The testimonies demonstrate how the official supply system has failed to deliver basic pain medication which causes emotional distress to patients.

The scarcity situation made people change their daily routines according to multiple participants. The high prices and unavailability of products in Valles del Tuy forced residents to share their medication and reduce their dosage for extended usage. The practice of medicine supply management through informal prescription sharing and dose reduction demonstrates both creative problem-solving as well as very high risk dangerous consequences because families had to stretch their limited medication supplies.The participants chose to purchase medications from outside their country because they had no other options left.

The mother from Maracay described her experience of buying medicine in Cúcuta after her son developed asthma because the hospital refused to provide oxygen, “the experience made me understand that we needed to leave the country.” The situation forced her to migrate to Colombia with her family after she obtained medication in Cúcuta.

The participants from different areas shared similar experiences about medicine shortages which they viewed as both a system failure and a heavy emotional and moral challenge. The participants displayed three main emotional responses to the situation: they worried about their family members’ worsening health and felt responsible for their inability to help and even lost faith in the healthcare system they used to trust. The widespread nature of these accounts demonstrates that medicine shortages represent both a national healthcare emergency and a personal indicator of Venezuela’s failing healthcare system.

4.2 Theme 2 →Substandard Public Hospital Conditions

Nine participants painted a grim picture of the extent to which Venezuelan public hospitals were very overcrowded, dirty, chronically under-resourced and unsanitary. Together, their accounts offer a glimpse into how systemic infrastructure failure has transformed the very meaning of hospital care from a site of treatment to one of uncertainty and survival.

A Guarenas woman described, “In public hospitals it’ s a mess, there are too many patients, no medicine, and sometimes not even water. And you sit there for three hours only to be told there’ s no specialist available.” Her experience is a mirror of the common experience of trying to work one’s way through institutions which can no longer maintain minimum standards of hygiene or even effectiveness.

A third participant from Caracas shared her mother-in-law’s ordeal after falling: “There, at Salud Chacao, they took an X-ray and said there was no traumatologist, we had to carry her across town to El Llanito and there were not even painkillers. Imagine seeing an old person in pain and being told there’ s no basic pain medicine.” This accounting of pain shows how staff shortages and supply deficits are magnifying suffering ushering routine emergencies into the territory of traumatic scourge.

A health-office worker who used to oversee public-sector spending gave an infrastructure-oriented explanation: “I could look at paper and see how little money was given versus what communities needed. This was always a gap between what people needed and what they could get.” And her double identity as administrator and patient bridges personal experience as well as systemic dereliction.

Some also relayed what they had seen of medical personnel being run ragged with unmanageable work duties where one woman said, “You see a doctor alone trying to assist 20-something people with not one glove nor disinfectant, absolutely nothing. After hours of waiting, most leave without being seen.” In the eyes of patients, these images of sick and very exhausted staff serve as visual reminders that the public health system had tragically caved from within.

In all of these stories, public hospitals serve as concrete avatars for Venezuela’s broader institutional collapse as respondents didn’t depict them as isolated failures but rather demonstrated how they were the product of visible outcomes from a chronic underinvestment, staff migration, and bureaucratic rot. Their stories demonstrate how systemic failure undermines trust by forcing patients to rely on private clinics or informal options whenever they can.

4.3 Theme 3→Specialist Shortages and Delays

Most participants described long waiting times and difficulty accessing medical specialists such as cardiologists, neurologists, and oncologists. These delays were not isolated inconveniences but structural outcomes of Venezuela’s shrinking medical workforce and deteriorating hospital capacity as participants consistently framed these shortages as both a medical as well as psychological burden turning treatable conditions into prolonged uncertainties.

A man from Caracas recounted, “My mother had tachycardia. At the emergency room, the EKG machine wasn’t working and there was no cardiologist. We had to take her to a private hospital.” His story reveals how technical failures and missing personnel really forced families to seek private care regardless of their financial hardship.

A former Indigenous Health Office employee offered a similar account from the administrative side: “My father needed a cardiology exam. Every hospital said the same thing, the machine was broken, or the technician wasn’t there. In the end, we had to pay privately, and my family had to pool money just to make it happen.” Her testimony links institutional scarcity to unequal outcomes where access depends on financial capacity rather than the patients medical needs.

Another participant from Caracas recalled the fatal consequences of these delays: “We took my mother to Vargas Hospital for an emergency. They didn’t even run tests, they just said she was fine and sent her home. Two days later, she died. I can’t explain the anger and pain.” Her account conveys the moral, emotional toll of systemic neglect as well as the collapse of clinical accountability.

For others, the absence of specialists created a cycle of deferred care. A participant from Valles del Tuy summarized, “If you need a specialist, you travel to Caracas, wait weeks, and still might not get seen. People just give up.” These accounts show how spatial and temporal barriers combine to make even basic specialist consultations inaccessible.

Together, these testimonies portray specialist scarcity as both a symptom and a driver of broader healthcare inequality. The inability to access specialized treatment deepens existing vulnerabilities, particularly for older adults and those managing chronic illness. Specialist shortages thus stand as one of the clearest indicators of Venezuela’s fractured health infrastructure where time itself has become a form of rationed resource.

4.4 Theme 4→ Reliance on Private Care or HCM Insurance

As public healthcare deteriorated, many participants described shifting toward private clinics or even employer-sponsored insurance programs known as HCM (Hospitalización, Cirugía y Maternidad). This reliance on private coverage emerged not as a preference but as a survival strategy as an adaptation to the state’s withdrawal from healthcare provision. Participants’ narratives show that while private access provided greater reliability it also reinforced very deep financial inequalities and excluded those without stable employment.

A woman from Guarenas explained, “When my neighbor couldn’t get care in the public hospital, she went to a private clinic. It cost her everything she had, but at least she was treated. People say, ‘If you want to live, you have to pay.” Her statement captures both the necessity and resentment surrounding privatized care.

Several participants reported prioritizing jobs that offered HCM insurance as a healthcare worker from Caracas shared, “I took a position mainly because it included private health insurance. Public hospitals don’t have medicine or equipment, so you end up needing HCM for even basic care.” Insurance thus functioned as a form of social capital, one that actually determined not only medical outcomes but also employment choices.

Another participant highlighted the limitations of such plans: “Even with HCM, you still pay a lot out-of-pocket. The coverage runs out fast, and the prices keep going up. It’ s like having a lifeboat with holes in it.” Her metaphor reflects the precariousness of middle-class adaptation under crisis conditions.

For women, these disparities were compounded by reproductive health needs. A participant from Caracas noted, “There’ s almost nowhere left for gynecological care unless you pay privately. Public hospitals cancel appointments all the time, and traveling far alone doesn’t feel safe.” Her account illustrates how gender, safety, and mobility intersect to limit care options even for those with insurance access.

Across these testimonies, private healthcare appears as both refuge and reminder of inequality. While HCM coverage temporarily shields patients from systemic failure it simultaneously deepens divides between those with institutional protection and those without as participants portrayed this duality with ambivalence gratitude for access mixed with anger that survival had become conditional on wealth or employment.

4.5 Theme 5→Alternative Practices and Cross-Border Procurement

When official healthcare systems failed many participants described turning to alternative remedies and informal medication channels to manage illness. These adaptations ranged from home herbal treatments to complex cross-border purchasing networks coordinated through many relatives abroad. The accounts portray a spectrum of creativity and desperation which are strategies that temporarily alleviated suffering but also carried risks of misinformation and even inequity.

A woman from Guarenas shared, “People started using natural medicine as teas, herbs, whatever helped. We learned recipes from neighbors or online because the pharmacies were empty.” Her story highlights how traditional knowledge re-emerged as an informal safety net when biomedical options vanished.

A healthcare worker from Caracas described a similar pattern of cautious substitution: “When medicines disappear, you do what you can use home remedies, eat healthy, try to stretch the little medicine you have left. It’ s survival.” This pragmatic tone resignation without illusion echoed through many interviews.

For others, adaptation required geographic movement. A mother from Maracay who had ultimately migrated to Colombia, explained, “Every few months, someone from our neighborhood crossed the border to buy insulin or antibiotics. We all pitched in money and sent lists. Sometimes they came back empty-handed; sometimes they didn’t make the trip.” Her narrative shows how scarcity created collective networks of cross-border cooperation grounded in trust and necessity.

Participants viewed these alternative strategies ambivalently: they provided temporary control but also underscored dependence on unstable, unregulated systems. A man from Valles del Tuy summarized, “You feel proud that people find ways to survive, but also scared—because it shouldn’t be this way.” His reflection captures the tension between resilience and resignation that runs throughout the data.

Ultimately, these testimonies reveal that informal and transnational health practices have become integral to everyday survival in Venezuela. Yet the uneven access to information, money, and cross-border mobility means that such coping mechanisms often reproduce the very inequalities they are meant to alleviate.

4.6 Theme 6→ Preventive Health Behaviors

Six participants described developing preventive health routines as a way to reduce dependence on Venezuela’s collapsing medical infrastructure. With hospitals being unreliable and medicines scarce many prevention became a deliberate survival strategy as a an attempt to regain control in an unpredictable environment.

Participants framed these lifestyle adjustments not as wellness trends but as pragmatic risk management.A woman from Guarenas explained, “I try to eat well, exercise, and meditate. During the hardest years, when medicine disappeared, that was all we could do.” Her statement reflects how self-care practices became substitutes for unavailable treatments.

A healthcare worker from Caracas expressed a similar sentiment: “You learn to avoid getting sick. I rely on my job’ s small clinic, but mostly I take care of myself because public hospitals are too dangerous.” The combination of precaution and fear shows how prevention emerged from distrust rather than health promotion.

Another participant from Venezuela’s Indigenous Health Office connected this shift to structural awareness: “After seeing how little funding there was, I started saving money for emergencies and taking vitamins. Prevention is cheaper than depending on the system.” Her comment reveals an economic logic to self-care, framing it as an investment in personal resilience.

Across these accounts, preventive health practices carried both empowerment and burden; they offered participants a sense of agency yet simultaneously transferred responsibility from institutions to individuals. A man from Guarenas summarized this trade-off: “It’ s good to be healthy, but it’ s also exhausting because you’re doing the government’ s job.”

These narratives highlight the privatization of risk at the household level and prevention, once a public-health goal, has become an individual coping mechanism as a an act of necessity shaped by structural abandonment.

4.7 Theme 7→ Community Fundraising and Support Systems

When formal health systems broke down the respondents narrated seeking solutions through traditional and informal medicine for their ailing bodies. These adaptations covered different levels, from herbal treatment in the home to intricate transborder shopping strategies passed on through relatives living abroad. The accounts reflect a range of creativity and desperation strategies that offered such temporary relief while also posing the risk of misinformation, expense, and inequality.

One health-care worker in Caracas said that these were part of the gradual process of standing-in: “You do what you can because when medicines vanish from the store shelves, you have to treat yourself at home and eat healthfully and stretch out the last bit of prescription drugs. It’ s survival.” This pragmatic coarseness of resignation without illusion sounded through many interviews.

Others had to move geographically to adapt, “From time to time, someone we knew would go over and buy insulin or antibiotics,” said a mother in Maracay who eventually relocated to Colombia. “We all chipped in money, and we sent lists. Sometimes when they went out in the morning, they didn’t come back with anything; sometimes they never left.” Feign’s story illustrates how the scarcity generated cross-border networks of collective action based on trust and mutual need.

Such alternatives were actually only weakly accepted by the participants; in a way as they gave temporary power but at the same time repeated and underlined an insufficient dependency on unstable, unregulated systems. A man from Valles del Tuy put it like this: “You feel proud that people are finding ways to survive but also scared because people shouldn’t have to do things this way.” His reflection is a poignant tension between that of resilience and resignation that courses through the data.

Ultimately, these testimonies illustrate that informal and transnational health practices are now central to everyday survival in Venezuela but the unequal ability to access information, money, and cross-border mobility means that these coping strategies can themselves replicate the inequalities they are intended to ameliorate.

5. Discussion

5.1 Understanding Patient Adaptation Through Resilience

The research results show that Venezuelan patients’ healthcare collapse experiences extend beyond institutional breakdowns because they demonstrate intricate social and psychological adaptation patterns which align with resilience theory. According to Norris et al. (2008) community resilience exists as the ability of social systems to withstand disturbances while keeping their fundamental operations intact. While according to Ungar (2018) resilience emerges through the continuous interaction between personal initiative and environmental resource availability. The presented stories show Venezuelans performing both individual adaptation and social environment boundary adjustment at the same time.

The coping strategies of participants including preventive health practices and informal medication distribution and private insurance usage and community-based fundraising efforts demonstrate the interconnected systems which Norris and Ungar describe. People use “navigation and negotiation” according to Ungar to find or even establish alternative resource access routes when faced with restricted circumstances. The adaptive strategies people use to cope with their situation demonstrate how digital networks function as a replacement for missing state-based infrastructure. The adaptive capacity shows uneven distribution patterns among the population. The research supports Norris et al. (2008) who state that resilience depends on four essential domains which include economic development and social capital and information and community competence yet these resources remain unevenly accessible in present-day Venezuela.

The research indicates that patients demonstrate remarkable resourcefulness but their adaptive actions take place within systems that maintain significant social inequalities. Women encountered multiple barriers which restricted their ability to join resource-sharing networks because they faced limitations in mobility and safety and reproductive healthcare access. The anthropological concept of “bounded resilience” describes their situation because they showed bravery through adaptation yet their actions remained restricted by structural barriers.

The research evidence contradicts positive views about resilience as a solely empowering force and it also reveals that people must take on institutional responsibilities when public institutions abandon their duties which results in resilience becoming a sign of systemic failure. The Venezuelan patients’ ability to adapt serves as proof of human flexibility yet it also reveals the unacceptable circumstances which force people to endure such hardships.

5.2 Gendered Vulnerabilities and Health Inequality

The research findings from women participants demonstrate that gender plays a fundamental role in determining how Venezuelan women experience the collapse of their healthcare system. Women took on dual responsibilities by providing care to their families while simultaneously acting as medical coordinators who located medications and arranged transportation and handled healthcare costs. The gendered tasks women performed during this time increased their stress levels and financial difficulties which strengthened existing social and economic inequalities.

A woman who lives in Caracas described her multiple responsibilities when she stated, “You need to perform all nursing duties and medical tasks and psychological support and financial management for your family members.” The statement demonstrates the “care work paradox” which feminist scholars describe as women taking on unpaid work to replace absent institutional care according to Hochschild (1995) and Tronto (2013).

The research data indicates that women experienced different levels of risk because of their reproductive and chronic health requirements. Women participants explained that they experienced prolonged delays when trying to obtain gynecological care and birth control methods and prenatal medical assistance. The participant described her experience of seeking gynecological care in Caracas because she needed to travel long distances but doctors frequently canceled her appointments.

Women who are pregnant or have medical issues must handle their health needs independently because they lack proper care. The breakdown of healthcare systems leads to increased health dangers for women and restricts their ability to control their bodily autonomy. Women encountered special risks when seeking medical care because they needed to navigate dangerous areas while dealing with transportation problems and security threats. The participant from Maracay expressed her fear about needing Caracas treatment because bus services were unavailable. The combination of gender with geographical location and security risks produces what scholars call “layered precarity” (Butler, 2016) which restricts women’s ability to make decisions.

Women showed impressive organizational abilities despite facing numerous obstacles in their community such as organized medicine-sharing programs and operated online fundraising campaigns and distributed health information through WhatsApp messaging. Women’s ability to solve problems through resourcefulness continues to perpetuate the societal norm that they should handle institutional breakdowns through emotional work and logistical management. The participant expressed her question about why mothers consistently need to find solutions for every problem.

The research results support feminist anthropological theories which demonstrate that health emergencies reveal and intensify existing social inequalities as the social structure of gender determines how people experience risk exposure and healthcare access. Women in Venezuela experience both the power of their social connections and the weight of enduring a healthcare system that ignores their needs.

5.3 Policy Implications and Structural Change

The healthcare crisis in Venezuela exists beyond resource shortages because it stems from fundamental problems with system organization and unequal distribution of resources. The solution to these problems needs both emergency policy solutions and enduring structural changes to healthcare systems as the healthcare system needs to focus on these essential priorities that participants identified to rebuild trust and minimize gender-based and geographic healthcare inequalities.

The healthcare system needs to create dependable systems for medication distribution across the country. The participants in this research study all mentioned their struggles to get necessary medications which proves that Venezuela needs better medicine procurement systems and improved distribution networks with monitoring capabilities for all regions. The stabilization of pharmaceutical access through international humanitarian organization partnerships should include oversight systems to stop diversion and corruption activities.

The government needs to create official programs that protect patients who need medical treatment outside their home country. The participants needed to use unofficial networks to buy medication outside their country which exposed them to dangerous situations and legal consequences. The government should also establish controlled humanitarian medication import systems through official agreements with Colombia and Brazil. The current system of private and dangerous medication procurement would become unnecessary through these policies.

The healthcare system needs to create immediate specialized outreach programs which focus on treating women and patients who need ongoing medical care. The research shows that women face the most severe health problems which receive insufficient attention during reproductive and preventive care. Mobile health units together with regional telemedicine programs should be implemented to provide better healthcare services in underserved areas while minimizing travel-related dangers. The implemented measures need to adopt gender-sensitive approaches which account for women’s dual responsibilities in caregiving and their limited mobility.

The protection of financial resources for healthcare services must become a priority to stop the growing separation between different social groups in healthcare access. The current healthcare system operates based on wealth because most people depend on private insurance (HCM) and pay medical expenses directly from their pockets. The health system needs more than technical fixes because it requires public trust to be rebuilt as the participants expressed their sense of being left behind and their complete emotional depletion. The recovery of public trust in healthcare institutions depends on transparent governance and professional retention strategies and community involvement in health planning processes. The success of well-designed reforms depends on rebuilding trust between healthcare providers and their patients because without it these reforms will fail to benefit the intended population.

The proposed recommendations follow the principles of resilience frameworks developed by Norris et al. (2008) and Ungar (2018) which state that recovery success depends on building up social and institutional frameworks at the same time. The combination of supply chain improvement with humanitarian channel legalization and gender-focused policies will enhance healthcare results while bringing back the lost sense of national security.

5.4 Study Limitations and Future Research

As with all qualitative inquiry, this study has several limitations that should guide the interpretation of its findings.

First, the sample was relatively small and although it reached regional diversity between age groups, it cannot be generalized to all women in Venezuela. The study’s aim was depth rather than breadth and its findings should not be taken as statistically generalizable but illustrative.

Second, recruitment occurred through WhatsApp networks and snowball sampling leaving out consideration of those without digital access or outside their social network. As a result, the lives of the most marginalized groups, like people in rural areas who do not possess smartphones or are in absolute poverty, may have been unaccounted for.

Third, the 3-day window of data collection precluded follow-up interviews or even longitudinal tracking. Further fieldwork over a longer term might show how coping strategies shift with continued economic or political changes.

Fourth, all interviews were translated from Spanish to English and some nuance may have been lost in translation despite the benefit of careful checking. Future research would gain from bilingual analysis or Venezuelan co-researchers to increase cultural and linguistic precision.

Lastly, the study focuses on gendered experiences and does not provide in-depth analyses of how class, ethnicity, and disability intersect. Future research could explore the interplay of these attributes with access to care and resilience strategies.

Despite these constraints, the study provides a valuable look at how average Venezuelans are dealing with a failing healthcare system. The uniformity of themes by respondents suggests that such issues are not few and far between and could be examined further through mixed-method or cross-regional designs.

6. Conclusion

The research investigates how Venezuelan patients experience the breakdown of their national healthcare system. The research used qualitative interviews with thirteen participants from different areas to document their daily experiences with medication shortages and insufficient hospital facilities and specialist shortages and their need to use private and informal healthcare services and the gender-based differences in healthcare access. The stories present a survival mechanism which people develop because of necessity which researchers term as resilience under constraint.

The participants demonstrate that their ability to cope with the situation exists without choice and has its limits as people and their families have developed survival methods through resourceful behavior, mutual support and personal sacrifices which demonstrate the moral and structural weaknesses of failed institutions. Women take on most of the responsibility for caring for others and managing healthcare services and maintaining household stability. The women’s community support work upholds social structures yet demonstrates how women consistently take on unpaid care duties because of societal expectations about their role.

The study uses resilience theory (Norris et al., 2008; Ungar, 2018) to demonstrate that adaptation depends on the availability of social, economic and informational resources which Venezuelan society distributes unfairly. The creative solutions patients develop show human capability but complete healing needs more than individual perseverance. The path to recovery needs people to work together while institutions must change and public trust needs to be restored.

The research joins multiple academic studies that analyze health emergencies as humanitarian crises while revealing their connection to social inequalities and governmental failures and ethical duties. The testimonies from participants demonstrate that resilience should never serve as a reason for the government to step away from its responsibilities. The recognition of resilience should lead to system reconstruction which will transform survival from improvised measures into an entitlement.

Acknowledgments

This research was made possible by the generosity of thirteen Venezuelan participants who shared their life experiences, including some of their most challenging moments. I am deeply grateful to those who assisted with translating the Spanish interviews into English while preserving the integrity and emotion of each story. I also thank everyone who contributed to transcription and offered valuable feedback throughout the research process.

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About the author

Hillary Porco

Hillary Porco is a senior researcher at NSU University School whose work centers on global health access, qualitative research, and health policy in Latin America, particularly Venezuela. She completed this project under the mentorship of Dr. Reed Jordan (NYU Public Policy) where her research interests include healthcare inequities, patient narratives, and community-based health systems. She intends to pursue a career in medicine and global public health.

The post Barriers to Healthcare Access in Venezuela: A Qualitative Interview Study of Patient Experiences appeared first on Exploratio Journal.

Abstract

As global demand for sustainable energy solutions grows, nanogenerators have emerged as a promising technology for the ability to convert various forms of energy into electricity at small scales. This review focuses on two particularly unexplored but rapidly advancing subfields: Moisture-sorption-based Energy Harvesting (MSEH) and Transpiration-driven Electrokinetic Power Generation (TEPG). Both technologies convert moisture and water flow into usable electricity without the need for external power sources. MSEH leverages the ion migration resulting from water molecule sorption and desorption on hygroscopic sorbents, while TEPG generates electricity through transpiration-like capillary-driven flow and electrokinetic interactions within charged nanochannels. Through an in-depth analysis of recent eight most highly cited publications in TEPG, this paper examines the impact of sorbent composition, form factor, and water environments on device performance. Researches yielded high results when sorbent were cotton-based systems, particularly those enhanced with conductive additives like Carbon Black and MXene, and in ionized water environments. Furthermore, the recent trends in the number of MSEH and TEPG publications simulates the early-growth trajectories of triboelectric and piezoelectric nanogenerators, highlighting their rapid growth and significant potential. Although the current power outputs are insufficient for commercial electronics, continued advancements in sorbent material and hybrid integration promise a strong future.

Keywords: moisture-induced energy harvesting (MSEH), transpiration-driven electrokinetic power generation (TEPG), nanogenerators, energy harvesting, sorbent material.

1. Introduction

As the global demand for sustainable energy solutions grow, harvesting energy from ambient environments, such as heat, light, and humidity, has opened a vital research frontier. Among these, Moisture-Sorption-Based Energy Harvesting (MSEH) offers a unique advantage: continuous operation under low-resource conditions. Through MSEH, energy can be generated through just a solvent and moisture: when water vapor sticks to a sorbent, it forms bonds and releases heat; when water evaporates off a sorbent, it absorbs heat from surroundings, which produces a cooling effect. During this process, constantly adsorbed and desorbed, water molecules interact with hydrophilic groups on sorbents, leading to ion migration, which generates voltage and current. More specifically, water molecules in the atmosphere interact with the hydrophilic parts of the sorbent. This interaction causes ions to dissociate and move from the surface inward. This movement of charges creates voltage and current—thus generating electricity. Figure 1 illustrates this process, demonstrating how moisture uptake and evaporation drive charge movement within a hygroscopic material.

Likewise, Transpiration Electrokinetic Power Generation (TEPG), employs passive water gradients to generate electricity through nano/microscale interactions. However, the key difference between MSEH and TEPG lie on its source of water uptake. Whereas MSEH absorbs atmospheric moisture, TEPG implements a capillary action to absorb water through a porous, hydrophilic sorbent—just like in plant stems in transpiration. As water evaporates, a continuous water flow remains as the sorbent pulls more water upward, and electrical double layer forms at the carbon/water interface, gathering protons on the wetside. Then, water flows through charged nanochannels and drags along ions, creating potential difference and electric field as a result. Through placing electrodes on two ends of the channel, the process produces usable electricity. Figure (b) illustrates the principle of TEPG, indicating how capillary-driven water flow and ion transport across nanostructures lead to voltage generation in carbon-coated cotton fabric. 

As electricity and power generation for both MSEH and TEPG processes are highly dependent on the sorbent’s ability to attract more water, sorbent selection and optimization possess vital influence on the efficiency of these two processes. Notably, Yun et al. (2019) implements a cellulose membrane for its highly hydrophilic porous abilities, while Kaur et al. (2021) utilizes microporous alumina ceramic. Out of the ten most highly cited articles on MSEH, seven researches indicated uses of hygroscopic cellulose structures, while three researches indicated uses of applied hydrogels, such as the nylon and hydrogel-based composite fiber in Chen et al. (2023). For all sorbents in the top ten highly cited articles in Moisture-Sorption-Based Energy Harvesting, hydrophilicity and porosity stood out as the two main determinants of energy generation performance. Further, an innovative study has been conducted in Bae et al. (2022), as they combine MXene (Ti3C2Tx) with cellulose, applying MXene’s metallic-like electrical conductivity for enhanced charge transport, while enhancing sorbent hydrophilicity, as surface functional groups, including -OH, -O, and -F, attach to MXene. The following review conducts a detailed analysis on notable trends in the MSEH and TEPG renewable energy and researches the effects of different sorbents on power generation, analyzing sorbent selection in the top ten highly cited articles in the field.

II. Market Growth and Applications of Nanogenerators

Despite its “infancy” status in 2015, the nanogenerat market has since grown exponentially. As of 2022, the nanogenerator market is already valued at USD 39.5 Billion, and it is forecasted to reach USD 67.44 Billion by 2030, growing at a CAGR of 8.2% (Virtue Market Research, 2025). Others report the nanogenerator market to grow at a CAGR of 18.8% by 2033 (Verified Market Reports, 2025). More specifically, one forecast estimates the triboelectric nanogenerators (TENGs) market, a section of the nanogenerator market, growth from USD 1.47 Billion in 2023 to about USD 13.56 Billion by 2033, a staggering ~24.88% CAGR over that period (Spherical Insights, 2024). This rapid acceleration reflects not only early-stage promise but also a clear shift toward mainstream adoption across sectors. With applications expanding across healthcare, agriculture, smart infrastructure, and consumer electronics, nanogenerators are gaining traction as key power generation sources of self-powered devices (Market Growth Reports, 2025).

Despite its mere certification in the lab environment, this technology holds vast potential as a low cost, low maintenance energy harvesting method, especially as sustainability and energy efficiency become global priorities. One of MSEH and TEPG’s notable applications include power generation for various sensors and detectors. In example, MSEH can be applied to power air quality monitors, while TEPG may be implemented to soil or plant monitoring systems in precision agriculture. Moreover, MSEH can be applied in wearable electronics to power low-energy health trackers or e-textiles and in smart packaging to maximize freshness of fruit/vegetable deliveries. On the other hand, TEPG can be embed in walls or roofs to harvest energy from water flow and temperature gradients. These technologies can further combine with other popular renewable energy technologies in the market, achieving higher sustainability. For example, a layer of transparent MSEH sorbent may be applied as a final layer on top of photovoltaics, enabling battery-free solar cells to be powered all through night. Although there are various factors still to be considered, both technologies hold significant potential in the future renewable energy generation.

Moreover, nanogeneration plays a vital role in diversifying energy sources. Suburban America suffers from blackout after blackout—Texas alone saw 264 major outages since 2000—costing over USD 15,000 to 90,000 in less than 30 minutes (Statista, 2017). However, nanogenerators may help resolve this issue. Since most nanogenerators, including triboelectric, piezoelectric, thermoelectric, moisture-induced, and transpiration-electrokinetic, do not require a major applied external force to generate electricity, they can minimize the losses from power outages by consistently circulating electricity through the system, until major electricity sources begin to supply as normal. 

III. Research Trends in Nanogenerators

In Figure 3, six keywords have been researched, including triboelectric (TENG), piezoelectric (PENG), thermoelectric (TEG), moisture-induced (MING), transpiration-driven (TEPG), and nanogenerators, using the Web of Science database accessed through the University of Washington online library. The primary y-axis exhibits the number of peer-reviewed articles for each nanogenerator subcategory, while the secondary y-axis indicates the number of peer-reviewed articles related to nanogenerators as a whole. Among the various nanogenerators explored over the past decade, 90% of them involves mechanical energy conversion—TENG (67.5%) and PENG (28.4%)—while other technologies rely on thermal or chemical energy conversions—TEG (2.2%), MING (1.6%), and TEPG (0.3%).

As shown in Figure 3, the number of peer-reviewed articles on nanogenerators has been rapidly increasing over the past decade, with an approximate increase of 549.65% between 2015 and 2024—a near sixfold increase in under a decade. This growth far exceeds increasing rates in broader “energy harvesting” publications, which also grew substantially—from 3,858, in 2015 to 9,226 in 2024. Most notable increases happened in mechanical energy subcategories, including the triboelectric nanogenerators, more than tenfolding from 218 in 2015 to 2,788 in 2024, and piezoelectric nanogeneratores, tripling from 202 in 2015 to 694 in 2024. The sharp increase in the number of publications not only indicate rapidly growing academic curiosity and attention on nanogenerators but also validates the technical feasibility of nanogenerators. 

Although not as significant as triboelectric and piezoelectric nanogenerators, more niche branches, such as the moisture-induced nanogenerators and transpiration-driven electrokinetic power generators have attracted attention to increasing number of researchers, as shown from the data above: moisture-induced increased from 3 in 2015 to 71 in 2024, while transpiration-driven increased from 1 in 2015 to 15 in 2024. Nevertheless, since water harnessing-induced energy generation is in the early stage as demonstrated by the figures above, it follows the early growth trajectories of TENG and PENG, as most research on these subfields have been conducted in the recent five years. This highlights a potential rocketing interest in the following couple of years. In fact, upon further data analysis, as shown in Figure 4, all keywords, even including “energy harvesting,” recorded the maximum R^2 value when data points were put into quartic equations. This quartic regression implies a steep increase over the past decade and a continuously increasing trajectory in near future. 

Table 1. Correlation coefficient values of the number of publications related to nanogenerators as a function

Since Moisture-Sorption-based Energy Harvesting (MSEH) and TEPG operate in low-light, low-thermal, and off-grid humid environments, its versatility projects a rapid growth in the following decade. For example, MSEH devices can be integrated into smart textiles, where nanostructured hygroscopic layers embedded in clothing harvest moisture and generate electricity to power low-energy sensors or health-monitoring wearables, eliminating the need for external batteries. Although designing and applying the new technology may take some time, this opens possibilities for energy-autonomous wearables in remote or off-grid settings. Moreover, with MSEH and TEPG’s recent successes to power small electronics in laboratory settings, scientists increasingly blur the boundaries between the nanogenerators’ subcategories, experimenting hybrid systems to maximize the system’s energy efficiency. For example, MXene, initially studied in TEPG for its conductive and hydrophilic properties, are now being explored in pizoelectric systems for its high mechanical flexibility and strength as flexible 2D structures, ideal for flexible sensors and energy harvesters,  surface functionalization, as the functional groups, such as hydroxl, fluoride, and oxide, alter symmetrical structures to induce piezoelectricity, and high conductivity (Bae et al., 2022). This cross-disciplinary integration reinforces the high potential in the advances of currently less-spotlighted subcategories of nanogenerators. 

IV. TEPG Key Sorbents and Performance Comparison

This section introduces key sorbents in the most cited literature within the TEPG community in the last decade and compares its specific performance, analyzing which composite materials recorded the highest efficiency.

One of most notable cellulose-based TEPG research, Yun et al. (2019), introduced a thin planar form cotton fabric (90 x 30 x 0.12 mm) coated with carbon black as the capillary medium. This carbon black coating provides a conductive pathway to channel the charge, also known as the “psuedostreaming” current. A single 90 x 30 mm panel produced an open-circuit voltage of 0.53V and short-circuit current 3.91 uA, leading to 2.1 uA power generation. The energy output per volume was reported as 1.14mWh/cm^3, indicating a specific energy capacity of 4.1 J per cm^3. This implies that a 2.2V LED light requiring ~20 mA could be lighted with several TEPG panels in series/parallel circuits, highlighting its vast potential as a passive energy generation source. The application of carbon black, a conductive and high-surface-area material, while the hydrophilic cotton provided continuous flow, resulting in modest energy generation at a low cost. 

Moreover, a study by Bae et al. (2020) further enhances the set up in Yun et al., applying calcium chloride (CaCl2) on same carbon-coated cotton fabric, to create a closed-loop water cycle that mimics transpiration. After a few drops of water are initially added to begin the capillary flow, as water evaporates, the CaCl2 absorbs the vapor and releases it to re-wet the fabric. The device remained in similar dimensions to Yun et al. (2019) but with an additional layer of hygroscopic CaCl2. This research’s most significant achievement lies on prolonged period of TEPG operation, as what would normally have continued for merely an hour continued energy generation for several days. Results indicated that the implementation of CaCl2 enhanced the output, as the voltage rose to 0.74 V and current to 22.5 uA from approximately 0.5 V and 4uAwithout. This increased the power generation to 16-17uW, extending its period to light an LED from an hour or two to a week.

Another innovative study has been conducted by Lv et al. (2020), as the research presents a simple, low-cost generator using commercial air-laid paper with conductive carbon ink. Here, the paper acts as the sorbent, providing porous network for water transport, while the carbon ink forms a conductive film/electrode on the paper, simulating transpiration with commercially available products. Having one end of the paper strip slightly dipped in lithium chloride (LiCl) solution and the other end exposed, a continuous capillary flow has been formed to generate electricity. The strip is very thin and flexible (6 cm x 1 cm), and a single trip produced a continuous open-circuit voltage of 0.35 V and 33.9 uA under ambient conditions, corresponding to a raw 10^-5 W power generation. However, when dipped in de-ionized water, the performance recorded 0.17 V and 7.2uA. This further indicates that higher electrolytic solutions leads to better performance, due to enhanced electrical conductivity. The simple set up provided great stability, as the system had a consistent output over 120 hours, powering small electronics, including an LED, a pocket calculator, a digital watch, directly from TEPG. Despite cheap materials, the research widened the scope of materials implemented in TEPG, nearing power generation in advanced lab settings. 

At last, other than natural cellulose-based fabric, Kaur et al. (2021) employs a porous ceramic (α-alumina) block as the water transport medium. The alumina had ~35% porosity with 50-200 interconnected pores. Without any additional conductive coating, the bare ceramic generates electricity once wet, due to its surface charge—alumina pores carry a negative charge in water. In this study, a 3.0 × 3.0 × 0.3 cm^3 rigid alumnia block was used, substantially thicker than the fabrics used in other studies. To simulate plant transpiration process, one end of the block is placed in water (~1.5 cm deep), while the other end is exposed to air, establishing a capillary-driven water transport pathway that enables continuous upward water flow and evaporation. As the alumina block was a rigid ceramic, it demonstrated lack of flexibility. However, the device was durable enough to function over a year in ambient conditions, compensating for the inflexibility. The system recorded an open-circuit voltage up to ~0.27 V stable output in standard ambient conditions, while it recorded a low short-circuit current ~1.2uA. The maximum instantaneous power was calculated as only 0.324 uW, but this output could be sustained over months with stable set up. Overall, the microporous alumina proved effective due to Alumina’s surface chemistry: Alumina’s negative OH- creates a strong EDL, and as water moves H+ cations drag, accumulating charge. The alumina ceramic demonstrated clear trade-offs: while it remained stable over a long period, avoiding issues of material delaminatoin that carbon coatings faced, it also recorded a particularly low short circuit current, as the conduction is only via ionic streaming, not electronic, leading to high internal resistance. 

Table 2. Performance Comparison of TEPG Studies Published in Recent Literature. Specific power (mW/cm³) was calculated based on maximum power using Voc and Isc. Exponent [1] indicates testing in deionized (DI) water, while [2] indicates testing in ionized water.

Table 2 demonstrates the 8 most highly-impacted publications on TEPG, including information on each research’s performance (open-circuit voltage & short-circuit current), sorbent composition, form factor, and specific power. The table reveals natural cellulose-based sorbent to be the predominant sorbent model in TEPG, often enhanced with advanced materials that exhibit high hygroscopicity. In fact, the most highly cited and best-performing articles—Bae et al. (2020), Yun et al. (2019), Bae et al. (2022)—all used cotton combined with another material as their sorbent, highlighting the potential of enhanced cotton in TEPG.  Additionally, the exponent numbers in the performance section indicate whether the experiment was conducted in deionized water [1] or ionized water [2], for more accurate comparisons.
The specific power was calculated through the following two equations with available open-circuit voltage and short-circuit current data. The calculated specific power is the maximum specific power that could be achieved in each experimental setting. 

Some researches, including Yu et al. (2024) and Su et al. (2023), investigated performances under both deionized water and ionized water environments. As shown in Table 2,  both studies yielded better performance in ionized (salt) water. Moreover, although Bae et al. (2020) replicates the experimental settings in Yun et al. (2019), it yielded greater specific power, as Bae et al. (2020) conducts the experiment in ionized water while Yun et al. (2019) in deionized water. When TEPG is conducted in ionized water environments, the presence of ions enhances charge carrier density and electrokinetic flow, increasing both voltage and current outputs. Though, values from deionized (pure) water hold greater significance, as most situations where TEPG and MSEH will be applied comprise ambient moisture or deionized water. However, in Bae et al. (2020), it was noted that without CaCl2 or other salts, the device stopped working within ~1 hour due to lack of moisture retention and ion supply. This still implies that there is a long journey that awaits before TEPG is applied commercially.

In conclusion, the comparative analysis of recent TEPG studies highlights the significant impact of sorbent composition, form factor, and water environments on device performance. Cotton-based systems, particularly those enhanced with conductive additives like Mxene and polyaniline (Bae et al., 2022), exhibit the highest specific power outputs—reaching up to 658.93 uW/cm^3. In contrast, ceramic and simpler textile setups, such as those using microporous alumina or uncoated cotton, display notably lower performance. Although it current performance do not yield enough to power daily electronics, considering its continuously rising performance over the past years and its ‘supernova’ status suggest a promising future. 

V. Conclusion

By examining the current research trends in moisture-sorption-based and transpiration-driven electrokinetic energy harvesting, it is evident that they hold significant potential as rapidly growing subfields within nanogenerator research. Both the number of publications and the performance of reported devices have shown a steep upward trajectory in recent years. Although current outputs in TEPG remain in the microampere range—insufficient for commercial electronics—continued progress highlights its potential viability, especially when the system reaches the milliampere range. Moreover, as hybrid technologies, where MSEH and TEPG systems complement more promising energy generation technologies, develop, they will play a vital role in decentralized, location-optimized power solutions for sensors, wearables, and other low-energy devices. 

IV. Acknowledgement

I would like to thank Professor Dichiara for his guidance throughout this study. His consistent support and insights have been pivotal to completing this research.

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About the author

Jinwook (James) Chang

Jinwook is an aspiring environmental innovator bridging environmental science, energy, and policy to drive sustainable solutions from the lab to the real world. Part scientist, part historian, James draws on lessons from the past to shape innovations that power a cleaner tomorrow. (Website: https://www.jamestechgarage.com/)

The post Novel Nano generation Technologies for Harvesting Electricity from Water-Induced Processes appeared first on Exploratio Journal.

Abstract

With more industrial developments, there is an increased demand for clean energy. One source that can provide clean energy is hydrogen-based fuels. In the paper, the term “hydrogen power” means all energy generation methods based on hydrogen, such as hydrogen combustion or hydrogen fuel cells. However, generating hydrogen at an industrial scale requires scaling up hydrogen generation processes such as electrolysis. This depends on selecting suitable catalysts to expedite the process. This paper provides a review of existing theories that help identify potential catalysts for this process. Specifically, d-band theory and spinel theory predict the activity descriptors for Oxygen Evolution Reactions and Hydrogen Evolution Reactions, respectively.

Keywords: water electrolysis, hydrogen evolution reaction, oxygen evolution reaction, catalyst, d-band theory, spinel theory

The current world and social structure depend on generating electricity. There are various approaches to generating electricity, with the main options being using fossil fuels (combustion), renewable energy, and nuclear energy. In most fossil fuel generators, byproducts, mainly in the form of greenhouse gases (GHGs), will be produced due to the combustion reaction, and GHGs are capable of warming up the Earth’s climate and polluting the atmosphere (Markandya & Wilkinson, 2007, p. 979). According to data collected by a research team that published the findings in the journal “Earth System and Scientific Data,” a rigorous academic journal with very transparent processes, which are then compiled by Climate Watch, an organization under the World Resource Institute, the annual GHG emissions from the entire world, measured in billion tons of CO2 equivalent, from 1850 to 2016, it increased from 1.4373 billion tons to 46.50 billion tons or approximately a 3135 % increase in emissions. Most of these emissions come from energy demands (World Resources Institute, 2022). According to the same source, about 33% of the world’s emissions in 2021 came from electricity and heating, the largest sector of global GHG emissions (World Resources Institute, 2022). The data shows that energy production is a considerable portion of the global GHG emissions. Thus, a clear and most impactful solution to climate change will be finding a clean or low-carbon energy source, as it will directly address 30% of global emissions.

There are many ways to produce clean and non-polluting energy, such as solar energy, which is generated directly from sunlight. However, these methods are not perfect. Most renewable energy sources, particularly solar energy, are intermittent or unstable, requiring additional infrastructure to account for the problem (Mathew, 2022, p. 5). This, combined with the lack of a large and powerful energy storage system, leads to grids with renewable sources having to depend on fossil fuels, creating additional GHG emissions (Mathew, 2022, p. 5). Additionally, these renewable energy sources consume many resources, particularly land. For instance, a 1000 MW fossil fuel power plant requires 1-4 km2 of land for the entire facility, while renewables require a lot more land, with solar requiring 20-50 km2, wind requiring 50-150 km2 , and biomass requiring 4000-6000 km2 (Rashad & Hammad, 2000, p. 213). These factors combined make most of the current renewable energy systems unable to generate electricity as effectively as methods like fossil fuel. They could potentially release additional GHGs from the extra land use and infrastructure. However, not all renewable energy sources have that problem, and using hydrogen power can prevent these problems.

Hydrogen has many advantages as an element in itself. It is a highly energy-dense element (in terms of mass), making it comparable with other standard energy production methods, such as fossil fuels like petroleum or coal, as shown in Figure 1 (U.S. Department of Energy, n.d.-b). Hydrogen power has an effective energy system that is proven by fossil fuels. The underlying principle of hydrogen power is the same as that of fossil fuels, converting hydrogen combustion’s thermal energy to steam’s kinetic energy by boiling water, finally pushing a turbine with that kinetic energy, and generating electricity. This process has been proven by decades of application and is widely used today. Approximately 42% of all electricity generation in the United States uses steam turbines (U.S. Energy Information Administration, 2023). Hydrogen also comes with the added benefit of not producing any pollutants when burned, with its byproduct being only water, which is the product of the hydrogen combustion reaction. Not only that, but hydrogen can also be used in fuel cells, which is another way to produce power efficiently, with its efficiency ranging from 40% to 60% (U.S. Department of Energy Energy Efficiency & Renewable Energy, 2010). Hydrogen is also an essential industrial element, as shown in Figure 2, commonly used in industries like agriculture, where it can synthesize ammonia, a key component in all modern fertilizers (WHA International Inc, 2023; World Nuclear Association, 2024).

Background and Literature Review

Despite the benefits of a hydrogen-based energy system, getting hydrogen clean is a challenge. There are various ways to produce hydrogen; however, most are produced using fossil fuels, which release GHGs. In fact, approximately 95% of the world’s hydrogen production is based on fossil fuels and releases GHGs (Rosenow, 2022). In the case of hydrogen power, generating power with hydrogen that has a considerable amount of carbon footprint attached to it during its production process will make the purpose of hydrogen power obsolete, and thus, using renewable or clean hydrogen is essential to ensuring the benefits of hydrogen power can be released at full potential. To better classify different types of hydrogens, color codes are assigned to them, with different colors representing different carbon footprint levels, as shown in Table 1 (National Grid, 2025). Based on the classification of hydrogen, for hydrogen power to be completely carbon-free, using green hydrogen is the best approach. Electrolysis is essential to creating green hydrogen, as detailed in Table 1. It works by splitting water molecules, which consist of two hydrogen atoms and one oxygen atom. Thus, running a specific voltage through the water molecules will break the chemical bond between the atoms and release the atoms themselves. This method is carbon neutral and does not release additional GHGs, assuming the electricity used for the electrolysis is carbon neutral.

In an electrolysis reaction, the electric current passed through serves as the activation energy of the reaction to dissociate water molecules into hydrogen and oxygen. This happens because when an electrical current is passed through the anode, cathode, and the water itself, the water molecules undergo oxidation at the anode, producing oxygen gas and releasing electrons. At the same time, the hydrogen from the oxidation is also reduced at the cathode, where hydrogen ions are being reduced by gaining an electron from the oxidation at the anode, finally creating both hydrogen and oxygen gas at the ends. This process, however, is very energy- intensive as it needs to overcome a strong energy barrier presented by the OH bonds in water. These bonds in water have an average bond energy of 461.5 kJ/mol, an accepted value, which is quite strong (Song & Le, 2013). As a result, for the reaction to occur, more energy has to be passed through, making the process less efficient and more challenging to complete, decreasing the possibility for it to be used in large-scale industrial processes such as generating hydrogen in large enough quantities to supply power plants without a method to decrease the amount of energy used.

As a result, catalysts are being used to lower the amount of energy needed in this process, as a catalyst can lower the activation energy of reactions while not consuming itself during the reaction (U.S. Department of Energy, n.d.-a). This can be used to boost the amount of hydrogen acquired from electricity, improving the efficiency of the electrolysis reaction. There are various types of catalysts with pros and cons, as well as having properties that are more inclined to support either the oxidation or the reduction reaction. In the industry, the key to successfully creating and commercializing the system for broad public use is to find a suitable catalyst that balances various qualities. This can be done by reliably identifying the activity descriptor, which represents a quantifiable indicator for a catalyst’s capability to catalyze a specific reaction, in this case, the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Thus, this paper focuses on reliably identifying the activity descriptors for the hydrogen and oxygen evolution in the water electrolysis reaction.

HER and OER

As established before, the HER reduces hydrogen ions, and the OER oxidizes water molecules to release oxygen. Generally speaking, the OER is more energy-intensive and slower than the HER because it has a more complex reaction mechanism. Specifically, there are four electron transfer processes during the OER, as shown in Figure 3. This multi-step process requires breaking the strong OH bond in water to generate oxygen. The four-electron transfer process also means that forming multiple intermediates is challenging (J. Li, 2022). This, in turn, creates kinetic barriers, making it much slower and requiring a higher overpotential (extra energy) to make the reaction happen. On the other hand, the HER only requires 2 electron transfers, meaning it is essentially a more straightforward process that is also easier to achieve comparatively (Dubouis & Grimaud, 2019).

Additionally, during the OER, various intermediates containing oxygen form on the catalyst and get absorbed onto its surface. The formation of these intermediates is a critical step in the process, as this is the only way catalysts can facilitate the breaking and formation of oxygen molecules, which are the intended product. However, this process is challenging to balance as too much binding force will slow down the overall kinetics of the reaction, and the reaction could become “stuck” (J. Li, 2022). This is not a problem for HER because hydrogen atoms and their intermediates are much smaller, easier to release from the catalyst, and involve fewer steps to convert to their molecular form of H2 (Dubouis & Grimaud, 2019).

d-band Theory and Catalyst Performance Prediction for OER

The d-band theory is a fundamental concept used to explain and predict the performance of a transition metal catalyst in a reaction, where it applies specifically to transition metals because of the filled d-orbitals (Bhattacharjee et al., 2016). The theory mainly revolves around the d-band center, which is the average energy level of electrons in the d orbital relative to the Fermi level and is the highest possible energy for electrons at absolute zero, which serves a crucial role in catalytic activity (Bhattacharjee et al., 2016).

The theory’s predictions depend on the relative position of the d-band center (Bhattacharjee et al., 2016). Regarding OER specifically, the theory can predict how well a catalyst binds with oxygen-containing intermediates such as OH, O2, and OOH. When the d- band center is closer to the Fermi level, the interaction between the catalyst and the reaction intermediates generally increases. Conversely, a larger proximity will weaken these interactions (Bhattacharjee et al., 2016). This does not mean that aiming for the highest d-band center (i.e., closest proximity) will be the best. As explained above, a too-strong interaction will hinder oxygen molecules’ release (desorption) and will have a lower efficiency overall. Using the same logic, if the d-band center is too low, the intermediates will not bind strongly, leading to a higher activation energy requirement for the reaction (Bhattacharjee et al., 2016). As a result, catalysts with an optimal d-band center are defined as those that can strike a good balance between adsorption and desorption, allowing for an efficient intermediate process without energy losses, meaning higher overall efficiency. This is because the optimal balance of the d-band center can minimize overpotentials, which will enhance catalytic performance by wasting less energy, leading to a higher energy efficiency, thus allowing more energy to be applied to the reaction itself, increasing the reaction rate (Bhattacharjee et al., 2016). Additionally, over-potential has side effects like releasing heat and increasing material/catalyst stress, which can lead to a shortened lifetime and be suboptimal for future industrial operations. On the other hand, a lower overpotential will help maintain the stability of the catalyst, reducing wear and tear and, as a result, prolonging its lifespan, ultimately leading to the development of cheap and practical catalysts (Dubouis & Grimaud, 2019).

Application of d-band Theory in Catalyst Manufacturing and Design

The d-band theory can be applied in catalyst designs and manufacturing, with it serving as the guiding principle for tailoring catalysts by adjusting the electronic structure via alloying or doping various materials (Chen & Zhang, 2022). The theory has been validated through Density Functional Theory (DFT) calculations, a standard tool for validating and studying catalysts, supporting the effectiveness of the d-band theory (Nørskov et al., 2011). As a result, the d-band Theory can be used as a foundational principle for designing more advanced catalysts that work best for water electrolysis because the d-band theory can enable researchers to have something tangible that they can change for different results (Chen & Zhang, 2022).

Limitations of the d-band Theory for Catalyst Design

Nevertheless, the d-band theory has downsides as it does not apply universally to all catalyst materials (Bhattacharjee et al., 2016). As different catalysts have different electronic structures and surface morphologies, these factors lead to different catalysts requiring a different descriptor that considers and optimizes these factors (B. Wang & Zhang, 2022). For instance, the d-band theory works because it is based on the d orbital electrons, which can play a significant role in reaction intermediates (Bhattacharjee et al., 2016). However, the theory cannot accurately predict the catalytic behavior for materials like metal oxides, on-transition metals, and complex systems, such as perovskites and platinum, because the materials’ structures are too complex to be oversimplified by the d-band behavior in d-band theory (Gorzkowski & Lewera, 2015; B. Wang & Zhang, 2022).

Brief Explanation of HER Mechanism

Moving on to the hydrogen side of the reaction. The HER is a crucial aspect of water electrolysis and the source of green hydrogen. However, despite being generally more straightforward regarding reaction mechanism, HER does not have a definitive or universal theoretical model to predict catalyst performance, unlike OER, which has the d-band theory (Zheng et al., 2018). This makes identifying the optimal catalyst for the reaction completely different and requires understanding and analyzing unique activity descriptors that are not universally applicable to HER. Thus, an overview of HER catalyst design theories is presented below.

Cation Distribution and Spinel Theory for HER Catalyst Design

For HER, a very promising approach in catalyst design is using Spinels. Spinels are a type of crystalline material with the general formula of AB2O4, where “A” and “B” represent different metal cations, and “O” represents oxygen (Elkholy et al., 2017). Spinels generally have a cubic crystal structure characterized by two potential types of sites where the cation can be situated: the Tetrahedral or A site and the Octahedral or B site (Elkholy et al., 2017). These materials are known for their robustness, high thermal stability, and electrical conductivity, making them ideal for industrial applications after an optimal catalyst based on Spinels is successfully developed (Elkholy et al., 2017). One example of spinel is CoFe2O4. In this case, the Co2+ ion occupies the tetrahedral (A) sites while the Fe3+ ion occupies the octahedral (B) sites, together with the four oxygen atoms forming the framework of the molecule (Gomaa et al., 2024).

As there are two sites where cations can reside, a balance needs to be reached between these cations, denoted by δ. The balance significantly affects the catalytic activity for HER, and research has demonstrated that catalysts with an optimal cation distribution can substantially improve catalytic performance. This is because there is a better electron transfer process for the reaction and a more optimized binding strength of the hydrogen intermediates similar to hydrogen (Gomaa et al., 2024). For instance, the spinel of CoFe2O4 is an optimal catalyst for HER. CoFe2O4 has a cation distribution of δ of 0.33, and further research shows that CoFe2O4 exhibits low overpotentials, as low as 66 mV, which is advantageous as low levels of overpotential generally translate to a higher reaction efficiency (Gomaa et al., 2024; Niu et al., 2020). The arrangement of cations in the sites will influence the electronic structure of the spinel, similar to the d-band theory but with much more complicated mechanics (Gomaa et al., 2024). This change in electronic structure will optimize the interaction with hydrogen intermediates, reaching the right balance of binding strength (Exner, 2022).

Hydrogen Adsorption and Desorption Energy for HER Catalyst Analysis and Design

In addition to cation distribution, hydrogen and hydroxyl ions (OH-) adsorption energy has a crucial role in HER, which is especially important in alkaline media with a higher concentration of hydroxyl ions. In a study conducted by Baghban and colleagues, they used DFT to calculate the adsorption energies and achieved a 96.7% accuracy on predicting the behavior of actual catalysts (2021). An ideal catalyst for HER will exhibit a Gibbs free energy close to zero for hydrogen adsorption, meaning it will need less and less energy for the reaction to happen, or, in other words, a lower activation energy given that the catalyst can also efficiently adsorb and dissociate water to provide hydrogen for the reaction (Hu et al., 2016).

Outlook for HER Catalyst Descriptor

Due to the unique nature of the HER, it is essential to consider the current outlook for catalyst design. There are promising developments for HER catalyst descriptor analysis, but a universal and consistently working descriptor theory for HER still does not exist (Dubouis & Grimaud, 2019). Unlike in the case of OER, HER cannot use d-band theory because of complications, and other theories suffer from the same problem, causing the lack of a consistently working universal descriptor theory for HER. The HER involves diverse electronic properties observed in materials available for HER, making it very challenging to establish a single definitive set of rules or descriptors that can apply universally (Du et al., 2025). Admittedly, the d-band theory cannot predict catalysts under all circumstances as previously established, but it is still a valuable OER catalyst analysis approach, which is “better” than the current HER situation. As such, future HER research should focus on developing a more comprehensive theory, allowing the community to progress towards a more comprehensive theory while enabling other potential research areas.

Conclusion

As established previously, energy is critical for society, so developing a clean energy source is also essential. However, current energy generation options have significant limitations, such as pollution or scalability. Specifically, despite being cheap and efficient, fossil fuels are very polluting, while on the other hand, despite being clean, solar power and other renewables are less efficient, intermittent, and consume large amounts of resources to create a working system (Rashad & Hammad, 2000). An alternative to all these methods exists: using hydrogen as a clean fuel source. Hydrogen is an excellent alternative to fossil fuel, as it has a high energy density and low emissions (Hossain Bhuiyan & Siddique, 2025). In addition to that, hydrogen also matters in other fields, as it is an essential industrial resource. The side product generated by green hydrogen production, oxygen, also has an essential industrial application, making green hydrogen production even more tempting (Eckl et al., 2025; U.S. Energy Information Agency, 2024).

Despite these benefits, hydrogen production is mainly achieved using fossil fuel (steam reforming), where 62% of all hydrogen production relies on natural gas (steam reforming), and around 99% of all hydrogen production requires fossil fuel and leads to carbon emissions (International Energy Agency, 2024). Therefore, when hydrogen is used in a hydrogen-based powerplant or a hydrogen fuel cell, it will likely have a carbon footprint comparable to that of normal fossil fuel. As such, developing a completely carbon-neutral method to produce hydrogen, specifically electrolysis, is essential. Nevertheless, electrolysis has problems because it is inefficient and not easily scalable, especially for industrial operations. To solve this issue, catalysts that can meet the requirements of an industrial system can be used to make the reaction less energy-consuming, hence allowing us to achieve efficient large-scale water electrolysis. This requires a theory that can reliably identify the respective activity descriptors for both the HER and OER. As discussed throughout the paper, the catalyst for the OER can be predicted using the d-band theory by optimizing the adsorption and desorption of oxygen-containing intermediates, whereas HER performance depends on more material-specific approaches and is generally harder to define. However, methods to identify the optimal HER catalysts exist, including understanding cation distribution in spinel systems that use catalysts of a specific format, such as CoFe2O4. These strategies demonstrate that by understanding electronic and atomic structures, specifically the d-band center in transition metal-based catalysts and spinel cation balance, the performance of catalysts for water electrolysis can be effectively and quantitatively predicted. In conclusion, optimizing catalyst selection and advancing in d-band and spinel theory or other potential theories are necessary for the bigger goal of large-scale clean hydrogen production. Therefore, more focus, funding, and research should be directed towards understanding and developing these catalysts to enable their industrial use, from energy production to industrial uses, not only laboratory applications.

This paper provides a review of the current available methods in identifying the activity descriptors for both the HER and OER and does not aim to find new methods or theories. To solve the problem of catalyst design, more experimental trials and data on catalyst designs need to be done, which will enable the potential for further understanding of catalysis or even potentially finding the catalyst that can be applied in the industry. Also, this review does not include all aspects of the research, as the paper only discussed the theories related to water electrolysis and their associated catalysts, which themselves can still benefit from catalysis research developments in other fields. Specifically, catalysis research has been done in fields other than water electrolysis catalysis, and we anticipate that future work could incorporate findings from those fields into the field of water electrolysis. Doing so can compile a more comprehensive and effective review, providing more value to the field.

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About the author

Jiajun Li

Jiajun is currently a 12th grade student at St. Andrew’s College. He is interested in physics, specifically nuclear physics, as well as environmental science, specifically the energy aspect. Jiajun is currently investigating how a clean and renewable energy source can solve most of the environmental crises that we are currently facing and how to develop future energy sources, such as advanced fission reactors and nuclear fusion reactors, which could greatly benefit society.

Jiajun is the leader and founder of his school’s physics club and a vital member of the environmental council, which has made significant progress on helping the environment within his school, including reducing food waste by over 20%. At his previous school, three other students and Jiajun succeeded in installing a solar energy system, and he is also planning the installation of a larger solar power system to power his current school.

The post Engineering Catalysts for Water Electrolysis: A Review of Activity Descriptors for Hydrogen and Oxygen Evolution Reaction appeared first on Exploratio Journal.

Abstract

The rapid development in the technologies of Unmanned Aerial Vehicles has ushered in a new era in precision agriculture, revolutionizing farm practices across the world. Equipped with multispectral, hyperspectral, and thermal imaging systems, UA Vs offer unparalleled capability for crop health monitoring, assessment of soil conditions, optimization in the use of fertilizers and pesticides, and improved water management. The current study investigates the huge potential for UA V technology to answer critical agricultural challenges, such as over-fertilization, excess pesticide use, and water shortages in Turkey, which have historically prevented sustainability and further efficiency. UA Vs can help farmers improve resource use significantly, lessen environmental impact, and yield better predictions with real-time data and precise intervention. This research reviews international case studies from areas like the Mediterranean and carries out regional questionnaires among Turkish farmers to analyze their UA V adoption barriers, such as high initial costs, inability to access technical expertise, and limited awareness of UA V capability. Large-scale and government-subsidized small-scale implementation of UA Vs within Turkish agriculture could help develop an overall modernization of agricultural techniques, increase profitability, and contribute to national objectives related to sustainability. Through such UA V-driven innovations, resource-use inefficiencies can be resolved alongside other environmental challenges, while long-term agricultural productivity and resilience are ensured for Turkey.

Keywords: UA V technology, remote sensing, precision agriculture, Turkey, sustainability, crop management, resource optimization

Introduction

Agriculture has traditionally been based on labor-intensive methods whereby farmers would observe field conditions and crop health by manual means. Traditional approaches to farming have usually led to several inefficiencies in resource usage and thus resulted in poor crop yields with greater labor costs. However, precision agriculture (PA) brought new technologies such as GPS, sensors, and data analytics, which revolutionized farming. Precision agriculture helped apply the most critical inputs of water, fertilizers, and pesticides with unprecedented precision. The sector has thus been able to receive a remarkable boost in productivity and sustainability [1]. This has lessened the burden, in terms of time and effort, placed on farm management while also encouraging better resource utilization [25; 18].

Generally, the rate of adoption of PA technologies has been increasing across the world. Examples of this increase have been seen in countries as; United States, Canada, and Australia, where digital agriculture solutions have completely revolutionized farming. In contrast, in Turkey, the rate of adoption can be considered quite low, although interest in the use of such technologies to raise agricultural efficiency is rapidly growing globally [25; 2]. Several reports indicate that drone technology seems to be the most promising approach in combating agricultural challenges in Turkey for modernization and better productivity [9].

UA V technology provides a great opportunity for farmers with active real-time monitoring abilities to enable fast assessments over large areas of agricultural fields without necessarily having an excessive amount of manual intervention. These will help develop an effective potential for reducing operational costs, hence making good precision in decision-making for the benefit of crop management. Studies have shown that UA V-based systems can reduce pesticide and fertilizer use and increase yield prediction accuracy for better sustainability in farming [26]. The new use of UA Vs in remote sensing, especially with multispectral imaging, is adding depth to farmers’ conclusions on their field conditions. This technology is considered vital for balancing the increasing global demand for food with the pressing need for environmental sustainability [5, 16].

Multi-spectral imaging enabled with UA V-supported remote sensing holds much transformational potential for agriculture. With the ability to take images in multiple wavelengths, including those in the Near-Infrared (NIR) part of the spectrum, UA Vs can work out plant health, soil conditions, and nutrient levels with remarkable accuracy. This imagery makes use of reflected light from the crop canopy in calculating such indices as NDVI (Normalized Difference Vegetation Index) for the computation of nitrogen and pesticide needs [27]. It has been reported in countries like China and Brazil that UA Vs may decrease pesticide consumption by up to 37% and raise crop productivity [29, 30, 28]. The fact that UA Vs are cost-effective and can deploy much quicker than ground-deployed methods bolsters a solid foundation on which UA Vs should be employed in Turkey, since agricultural efficiency improves through such technologies [26].

Despite its significant potential, UA V technology remains underutilized in Turkish agriculture, presenting a substantial opportunity for improvement. This research examines how deploying UA Vs to detect excessive pesticide spraying and over-fertilization can enhance resource management, increase crop yields, and reduce operational costs across Turkey’s agricultural sector.

Our study investigates three primary benefits of UA V technology adoption: improved resource management, enhanced yield monitoring, and greater economic sustainability. We hypothesize that increased implementation of UA V-based precision agriculture technologies will significantly improve crop yields while enhancing cost efficiency and time management through optimized resource utilization.

The paper also addresses current economic and technological challenges limiting UA V adoption in Turkey and proposes solutions based on successful implementation strategies from other countries. Our framework includes a critical review of UA V technology, its agricultural applications, analysis of relevant case studies, and recommendations for improving UA V adoption rates across Turkey.

Advanced UA V Technologies in Precision Agriculture

Unmanned Aerial Vehicles (UA Vs), commonly known as drones, have emerged as a pivotal technology in modern farming, transforming traditional practices through precision agriculture. By capturing high-resolution imagery and collecting environmental data across fields, UA Vs enable farmers to make evidence-based decisions regarding crop health, irrigation needs, fertilizer application, and pest management. This technology addresses the dual challenge of meeting increasing global food demand while promoting environmental sustainability [18]. UA Vs offer particular advantages over conventional monitoring methods due to their ability to rapidly survey large areas and navigate challenging terrains, making them adaptable to diverse agricultural landscapes. The two primary UA V designs used in agriculture—rotocopters and fixed-wing models—serve different purposes: rotocopters provide detailed observation capabilities through their hovering functionality and maneuverability, while fixed-wing UA Vs, with their extended flight times and greater coverage range, are ideal for monitoring extensive agricultural operations [5, 16]. These technological attributes position UA Vs as essential tools for modernizing agricultural practices, especially in regions like Turkey, where terrain diversity and varying farm sizes create unique monitoring challenges.

Multispectral and Hyperspectral Imaging

UA Vs can be equipped with multispectral and hyperspectral sensors that capture data beyond the visible spectrum, providing valuable insights into plant health and vegetation indices [19]. UA Vs with multispectral cameras have transformed traditional crop monitoring by capturing data across several key electromagnetic bands beyond visible light [8]. These sensors typically collect information in four to ten distinct spectral regions, including visible light (red, green, blue) and near-infrared (NIR) wavelengths. This multispectral data enables farmers to calculate critical vegetation indices such as the Normalized Difference Vegetation Index (NDVI), which measures plant vigor by comparing near-infrared light reflection (high in healthy vegetation) against red light absorption (linked to chlorophyll activity). Similarly, the Green Chlorophyll Index (GCI) provides specific insights into chlorophyll concentration, while other indices like the Enhanced Vegetation Index (EVI) offer improved sensitivity in high-biomass regions [5]. These quantifiable measurements allow farmers to identify spatial variations in crop development, detect stress factors before visual symptoms appear, and implement targeted interventions with precision. Multispectral imaging has proven particularly valuable for irrigation management, fertilizer application optimization, and early pest detection, enabling zone-specific treatments that reduce input costs while maximizing yield potential.

Hyperspectral imaging represents a significant technological advancement beyond multispectral capabilities, capturing hundreds of narrow, contiguous spectral bands across the electromagnetic spectrum. While multispectral sensors might collect data in 4-10 bands with bandwidths of 40-150 nm, hyperspectral systems typically record 100-300 bands with much narrower bandwidths of 5-10 nm [19]. This extraordinary spectral resolution creates detailed spectral signatures unique to specific crop conditions, enabling identification of subtlephysiological changes imperceptible to other sensing methods. The technology can detect variations in biochemical properties, including nitrogen, phosphorus, and potassium concentrations within plant tissues, differentiate between various disease pathogens before visible symptoms manifest, and identify moisture stress with remarkable precision [5]. Hyperspectral data processing often employs advanced machine learning algorithms to interpret the complex spectral information, creating highly detailed prescription maps for variable-rate applications. Despite higher equipment costs and data processing requirements compared to multispectral systems, hyperspectral imaging provides unparalleled insights for research applications and high-value crop production, where early detection of stress factors and diseases can prevent significant economic losses.

Thermal Imaging

Thermal imaging sensors integrated into UA Vs can capture data related to the canopy temperature of plants, providing critical information about their water status and stomatal conductance [8]. These sensors detect infrared radiation that can supply the variable of temperature to farmers over their fields. Variations in canopy temperature might indicate water stress, inadequate irrigation coverage, or even disease outbreaks. As summarized by Husain et al. (2023), “thermal imaging helps in identifying water-deficient zones and optimizes irrigation schedules, thus conserving water resources and enhancing crop resilience.”

Olson and Anderson (2021) also highlight the significance of thermal imaging in monitoring crop water stress, noting that UA Vs equipped with thermal sensors offer the Crop Water Stress Index (CWSI), which is a real indication of the actual status of plant hydration. This index provides substantial decision support for irrigation management by farmers, thus averting under- or over-watering. Farmers can thereby achieve optimization of water use, which may become crucial in arid areas where water scarcity is prevalent.

Image Stitching and Data Processing

One of the principal challenges in UA V-based agricultural monitoring is effectively managing the substantial volume of overlapping imagery captured during flight operations. As Olson and Anderson (2021) explain, “Image stitching is a key component for delivering high-resolution maps over large areas and enables high-resolution crop variability assessment and site-specific input applications.” This process involves algorithmically combining hundreds of individual high-resolution images into a single geometrically corrected orthomosaic map [12, 5]. The resulting composite provides a comprehensive, spatially accurate representation of the entire field that preserves the detailed resolution necessary for identifying subtle variations in crop performance. These orthomosaics reveal specific regions experiencing stress due to nutrient deficiencies, pest infestations, soil compaction, or water limitations that might otherwise remain undetected through traditional scouting methods. The geometric correction applied during processing ensures that measurements taken from these maps maintain spatial accuracy, enabling precise localization of problem areas for targeted intervention.

The transformation of raw UA V imagery into actionable agricultural intelligence requires sophisticated data processing beyond basic image stitching. Specialized software analyzes orthomosaics to extract critical information, including vegetation indices, plant height estimates, and canopy cover measurements [5]. As Husain et al. (2023) note, recent advancements in artificial intelligence and machine learning have dramatically improved the efficiency of this process, enabling “real-time analysis and faster decision-making” that enhances farm management responsiveness. These technological improvements, coupled with the emergence of cloud-based computing services, have significantly streamlined data processing workflows, reducing farmers’ dependence on expensive on-site hardware and specialized technical expertise [5]. The processed data ultimately generates practical outputs such as fertilizer prescription maps for variable rate application equipment and targeted pest management recommendations [5]. This complete workflow—from image capture to actionable recommendations—creates a digital decision support system that empowers farmers to implement precision agriculture practices with greater confidence and efficiency, maximizing both economic and environmental benefits through optimized resource utilization.

Yield and Nutrient Assessment

UA V-based remote sensing has revolutionized agricultural monitoring by offering efficient and non-destructive methods for yield and nutrient assessment. These aerial systems, equipped with advanced sensors, can capture detailed multispectral and hyperspectral imagery across large agricultural areas in minimal time. When this imagery is processed and analyzed, it provides crucial data enabling researchers and farmers to accurately estimate key crop parameters, including leaf nitrogen content, leaf area index, and plant biomass, all of which serve as valuable indicators for potential yield prediction [12]. For example, specialized studies have successfully demonstrated how UA V-based 3D photogrammetry techniques can measure crop height with remarkable precision, establishing strong correlations between these measurements and final corn crop yields [12]. This application is further emphasized by Olsson and Anderson (2021), who confirm that drones excel at “estimating leaf nitrogen content, which is very important for the optimization of fertilizer application and maximization of crop yields.” By enabling real-time monitoring of plant nutrient status through detailed spectral analysis, UA V technology facilitates precision fertilization strategies that optimize nutrient application rates and timing, thereby promoting healthy crop development while significantly reducing the environmental risks associated with over-fertilization and nutrient runoff into water systems [5, 16].

Furthermore, UA Vs have demonstrated exceptional capability in comprehensive nutrient management and yield forecasting through their sophisticated sensor systems. These platforms can simultaneously collect and integrate multiple data types, generating detailed crop health profiles that go beyond basic assessment. Husain et al.’s research highlights how UA V systems effectively employ specialized vegetation indices such as the Soil-Adjusted Vegetation Index (SA VI) to evaluate not only crop conditions but also underlying soil health and nutrient bioavailability patterns across fields. This advanced spatial analysis enables the creation of high-resolution nutrient management zone maps that allow farmers to implement variable-rate application technologies with unprecedented precision. By adjusting fertilization strategies according to real-time field data [5, 16], farmers can target inputs specifically where and when they’re needed, substantially reducing unnecessary application in already nutrient-sufficient areas. This precision approach delivers significant economic benefits through input cost reduction while simultaneously advancing environmental sustainability goals by minimizing nutrient leaching, runoff, and greenhouse gas emissions associated with excess fertilizer application, creating a win-win scenario for both agricultural productivity and ecological protection.

Precision Pesticide Application and Weed Detection

UA Vs are increasingly employed for precision pesticide application and weed detection, offering an environmentally friendlier alternative to conventional methods that often result in chemical overapplication. Equipped with precision spray systems, UA Vs can apply pesticides in a site-specific manner, targeting only affected areas rather than entire fields [11, 1]. According to Husain et al., drone technology enables targeted pesticide application that can reduce chemical use by as much as 30% while simultaneously lowering operational costs. This precision approach significantly minimizes the risk of pesticide drift and potential negative impacts on surrounding ecosystems. Weed detection using UA V imagery often employs deep learning-based methods to accurately identify and map weed infestations, creating detailed maps that enable variable rate chemical weeding and lead to significant savings in crop protection products[6, 8].

Furthermore, UA Vs enhance weed management through sophisticated detection capabilities using high-resolution cameras and spectral data analysis. These systems can effectively differentiate between crops and weeds, enabling precise herbicide application only where needed. “UA Vs fitted with high-tech imaging are able to detect infestations of weeds before they get out of hand, thus enabling the farmer to take control of them while still in their tender stages”[5]. This early intervention capability is crucial for maintaining optimal crop health and preventing yield losses from weed competition [8]. The integration of advanced imaging technologies with precision application systems creates a comprehensive approach to pest and weed management that simultaneously improves agricultural efficiency, reduces environmental impact, and enhances economic outcomes for farmers [11, 1].

Advanced UA V technologies in multispectral and hyperspectral imaging, integrated with thermal imaging, advance the new era in precision agriculture. Enabled by such technologies, farming can be optimized with increased resource use, yields, and management of more sustainable agricultural methods. The analysis of existing literature, when put together, creates a scenario whereby UA V not only changes the traditional ways of monitoring agriculture but also form the future innovations for sustainable farming. Equipped with thorough and timely information on crop health, water stress, nutrient levels, and management of pests, UA Vs put farmers in a better position to make informed decisions for increasing yields while lessening environmental impacts.

Agricultural challenges caused by climate change, resource scarcity, and increasing food demand continue to worsen. With these further challenges to farming, the role of UA Vs in precision agriculture will continue to play a vital part. Their application can further enhance the efficiency of agricultural operations beyond what was previously mentioned, in turn contributing to or supporting food security and sustainability goals. In each source, research and continued investments into the technology of UA Vs are highly emphasized as imperative for truly exploiting their potential in changing global agriculture.

Support Section I (Analysis and Literature Review)

Research conducted in various parts of the world has demonstrated that UA V technologies are of vital importance for optimizing resource use in agriculture; thus, they are envisioned as a promising solution for improving crop management in Turkey. However, despite their potential for further development and wider adaptation, the use of UA V technology for remote sensing of excessive pesticide spraying, over-fertilization, and yield monitoring in Turkish agriculture remains minimal. This situation creates immense opportunities to optimize resource use and improve crop yields, thereby enhancing cost and time management. Therefore, this section will review the existing literature to support the hypothesis that UA Vs can effectively address resource management inefficiencies in the agricultural sector. With UA Vs capable of monitoring pesticide and fertilizer use as well as crop health, the potential for driving sustainability, reducing input costs, and enhancing productivity becomes significant. These capabilities could substantially transform the landscape of Turkish agriculture, offering new pathways toward more efficient and environmentally sound farming practices..

How UA V Technology Has Impacted Agricultural Practices Globally

Unmanned Aerial Vehicle (UA V) technology has revolutionized agricultural practices worldwide by providing producers with enhanced assessment capabilities and facilitating more efficient decision-making processes. The global adoption of precision agriculture technologies, with UA Vs playing a pivotal role, continues to accelerate, with industry projections estimating a market value of $43.4 billion by 2025[4]. This remarkable growth trajectory underscores the agricultural sector’s increasing recognition of UA V technology’s transformative potential.

UA Vs offer farmers sophisticated options for assessing critical factors affecting agricultural systems. Color sensors mounted on UA Vs can accurately estimate leaf color, plant height, lodging, canopy cover, stand count, and even flower and fruit quantities[5]. Research has demonstrated UA V-based height estimation reaching an R-squared value of 0.51 with dry grain yield when measured at the beginning of August, illustrating its significant potential for yield prediction and comprehensive crop monitoring[12]. Beyond visual data, spectral sensors can estimate indirect leaf nitrogen content, yield potential, leaf area index (LAI), leaf chlorophyll content, and plant biomass. Additionally, thermal sensors capture vital data for estimating canopy temperature, stomatal conductance, water use efficiency, and plant water potentials[5]. Notably, Green Normalized Difference Vegetation Index (GNDVI) data acquired by UA Vs during anthesis and full crop development has produced accurate biomass estimates, with some studies reporting higher accuracy yield estimates with GNDVI as early as 5 weeks into a crop’s lifecycle [5].

The fusion of multiple data types significantly enhances assessment capabilities, with combinations of color, spectral, and thermal data products improving reliability and accuracy. Three-dimensional characterizations such as crop height or volume, derived from LiDAR or high-resolution color cameras and combined with conventional 2D data, can increase the accuracy of yield and quality estimates[5]. Further, the research has shown that combining plant height measurements with NDVI values has improved biomass estimation accuracy[5]. Additionally, radiometric correction of UA V imagery can significantly reduce grey value variation in overlapping images, from 14–18% to 6–8% under varying illumination conditions, further enhancing data quality[19].

The rich data gathered by UA Vs drives strategic decisions that enhance input efficiency, potentially maximizing return on investment while simultaneously reducing environmental impact. Studies conducted on Australian grain farms have estimated an increase ranging from $4/ha to $23/ha, with an average of $13/ha (8%) attributable to precision agriculture technology, including benefits from variable rate fertilizer application and reduced overlap in input distribution[21]. In another compelling case study from an Italian cereal farm, researchers documented a 53% reduction in pesticide usage during the post-adoption phase, largely attributable to precision sprayers[6]. This same farm experienced a 28% decrease in fuel consumption due to the implementation of newer, more efficient machinery equipped with advanced satellite guidance systems[6]. It is evident that UA V technology helps ensure precise pesticide application, utilizing fewer chemicals and minimizing environmental contamination[5, 16].

Precision agriculture technologies incorporating UA V data have demonstrated impressive efficiency improvements across multiple categories. Recording and mapping technologies (RMT) can lead to fertilizer savings ranging from 1.6–82% in peer-reviewed papers and 5–70% in EU projects. Variable rate technologies (VRT) have shown fertilizer savings ranging from 5–59% in peer-reviewed literature and 22–30% in EU projects. Guidance and Controlled Traffic Farming (CTF) technologies have reported fertilizer savings ranging from 1–26%, while Farm Management Information Systems (FMIS) have demonstrated fertilizer savings ranging from 14.7–46% in peer-reviewed papers and 5–70% in EU projects[14].

The applications of UA Vs in agriculture span numerous domains, including creating detailed fertilizer prescription maps, conducting hail crop damage assessments, enabling early pest detection, and generating crop yield and quality predictions[5]. UA V-captured multispectral imagery is used to assess plant health and nutrient status, enabling the creation of variable rate fertilizer prescription maps [3]. Methods like Ordinary Kriging (OK) and Inverse Distance Weighting (IDW) are employed for spatial prediction of soil properties for these maps, with modern approaches integrating data from digital elevation models and multispectral satellite images to enhance prediction accuracy [16].

The integration of UA V-based imagery with machine learning algorithms offers enhanced yield assessment accuracies while reducing reliance on labor-intensive ground-based surveys. Machine learning applied to UA V imagery has achieved classification accuracies ranging from 67 to 95% for identifying diseases like yellow rust, grapevine bacterial disease, myrtle rust, and citrus greening[5]. UA Vs equipped with multispectral cameras effectively assess plant health using Normalized Difference Vegetation Index (NDVI) and other specialized indices, detecting stress factors not visible to the naked eye[5, 16]. One study demonstrated that vegetation fraction mapping in wheat crops using a low-cost camera mounted on a UA V achieved impressive accuracies of 87.73–91.99% when operating at a height of 30 meters[8].

For crop yield and quality predictions, Partial Least Squares Regression (PLS-R) is widely used to analyze spectral data obtained by UA Vs, with PLS-R models for maize grain yield showing coefficient of determination (R²) values up to 0.86 in validation[15]. Hyperspectral data from UA Vs have been employed for wheat growth monitoring and yield estimation using methods like Multiple Linear Regression (MLR), Simple Linear Regression (SLR), and Partial Least Squares Regression (PLSR)[8]. The deployment of hyperspectral cameras on UA Vs shows particular promise due to their ability to capture broader spectral ranges than simpler multispectral cameras.

A major contribution of UA V technology has been its ability to gather phenotypic data quickly, efficiently, and non-destructively, significantly advancing crop improvement through genetics and plant breeding programs[5]. For instance, NDVI data generated from UA V imagery successfully identified quantitative trait loci (QTL) associated with drought adaptive traits in durum wheat, accounting for 89.6% of the phenotypic variance[5]. Biplot analysis, which can utilize data collected by UA Vs, has proven to be an effective tool for selecting superior genotypes and increasing efficiency in selection [3]. The rapid and comprehensive data collection capabilities offered by UA Vs greatly expedite field data acquisition for developing germplasm with desired agronomic traits.

In conclusion, UA V technology has transformed global agricultural practices by enhancing precision, efficiency, and sustainability. Research indicates that Farm Management Information Systems supported by UA V data show potential for yield increases ranging from 5-14%, fertilizer savings of 14.7-46%, and water savings of 10-50% [21]. As the technology continues to evolve and become more accessible, its adoption across different agricultural contexts promises further improvements in productivity and sustainability, helping address the growing global demand for agricultural products.

How Does Remote Sensing Save Resources Compared to Traditional Methods?

One key advantage lies in crop health monitoring. Traditional methods often involve visual inspection and manual collection of ground samples from random locations. This can be difficult, time-consuming, and may not provide a comprehensive overview, especially on large farms [13, 8]. Drones, however, can perform daily monitoring of crops to detect potential threats such as diseases, pests, and slow growth rates more effectively. They utilize aerial remote sensing, capturing images of different wavelengths to measure various parameters [1]. Drones can be equipped with different sensors, such as color, spectral (including near-infrared – NIR), and thermal cameras, allowing for the assessment of plant health indicators that might be invisible to the naked eye. This enables earlier detection of problems and facilitates quicker corrective actions, potentially preventing crop spoilage [8, 3]. The ability of drones to fly at low altitudes allows them to obtain high-resolution images with greater precision compared to satellites, which can be affected by cloud obstruction and have lower spatial resolution. While manned aircraft can cover large areas, they are often more cost-prohibitive than drones [2, 13].

In pesticide and fertilizer spraying, drone-mounted sprayers offer enhanced coverage ability and increased chemical effectiveness compared to conventional methods, which can be less effective in controlling pests and diseases [11]. Traditional spraying can also result in a higher cost of application. Drones can carry pesticide tanks (up to 40 liters in some cases) and follow pre-mapped routes to spray crops according to specific requirements; this capability allows for spot spraying in infected areas, reducing the overall amount of pesticides used and minimizing environmental impact [1, 8]. Drones can effectively cover fields with difficult access for tractors and aircraft. Furthermore, they can provide a more uniform and precise application of pesticides, operating at a standard delivery height and speed. Similarly, drones can be used for the application of fertilizers, making the process easier and potentially more efficient than traditional on-ground tools like tractors [13, 3]. Variable rate application of fertilizers and pesticides, guided by drone-collected data, directly translates to savings in resources [4].

Drones contribute significantly to resource management. The high spatial and temporal resolution data provided by drones enables site-specific management. For instance, drones with thermal sensors can detect temperature variations indicating water stress, allowing for efficient utilization of water through targeted irrigation and preventing water wastage [1, 13]. By identifying areas of nutrient deficiency or pest infestation, drones facilitate the precise application of fertilizers and pesticides, leading to reduced usage of these inputs. Studies suggest potential herbicide savings of 20% to 50% through precision application [14]. The data collected by drones, such as soil moisture information, can also be used to automate irrigation scheduling systems, further reducing water usage [3].

The efficiency in data acquisition by drones is a major benefit. They can cover large areas in short time periods and offer freedom from positioning and timing limitations compared to other remote sensing platforms [1]. The ability to collect data frequently allows for the detection of changes over time, which is crucial for effective agricultural management [8]. This data can then be analyzed using Artificial Intelligence (AI) and deep learning models for tasks like crop yield prediction, disease detection, weed mapping, and nitrogen status estimation, providing valuable insights for better management decisions [17]. This instantaneous data analysis capability allows for quicker responses to emerging issues [13, 1].

Several sources highlight the potential for cost and time savings with the use of drones. Farmers have reported that spraying and fertilization activities using drones save time and reduce costs due to less labor being required and the low cost of battery charging compared to fuel costs for traditional machinery [[13, 4]. Drone usage can significantly reduce labor costs associated with manual crop monitoring and pesticide application. For example, some studies indicate that drones save up to 20 times the labor of farmers [13].

Drones offer greater accessibility and coverage, especially in complex or difficult-to-reach areas. They can navigate terrains that are challenging for tractors and manned aircraft, ensuring that all parts of a field can be monitored and treated effectively [1]. Fixed-wing drones are particularly suited for large-scale surveys and monitoring vast agricultural areas, while multi-copters are often preferred for crop health monitoring and targeted interventions due to their maneuverability and hovering capabilities [16, 5].

Furthermore, drones play a crucial role in high-throughput phenotyping, allowing researchers and plant breeders to gather phenotypic data quickly, efficiently, and nondestructively. This includes estimating leaf color, plant height, canopy cover, stand count, flower count, and fruit count using various sensors [20]. Spectral sensors can estimate leaf nitrogen content, yield, leaf area index, and plant biomass, while thermal sensors can provide data on canopy temperature and plant water status [5].

In conclusion, drones offer numerous advantages over traditional agricultural methods by providing more efficient and precise crop monitoring, targeted resource application, improved data acquisition and analysis, potential cost and time savings, enhanced accessibility, and valuable tools for research and development in precision agriculture [18]. The increasing technological advancements and decreasing costs of UA Vs are making them an increasingly important tool for modern agriculture [8, 11].

Cost and Efficiency Comparisons

The increasing accessibility of UA V technology has emerged as a viable option for agricultural applications [8]. By 2019, complete agricultural-grade UA V systems—which included a UA V platform like the DJI Matrice 100, a sensor such as the MicaSense Red Edge MX, image processing software (e.g., Pix4D Fields), and necessary hardware—became available for under $30,000 [5]. This represents a significantly lower initial investment compared to traditional aerial imaging systems such as piloted aircraft, making UA Vs a more financially feasible solution for farmers [1]. Additionally, the proliferation of cloud-based computing services has reduced the need for substantial upfront investments in on-site image processing infrastructure, enabling farmers to efficiently process UA V-captured imagery without dedicated hardware and software expenses [5].

In terms of efficiency, UA Vs can cover significant areas in relatively short periods, leading to considerable time and labor savings compared to traditional ground-based monitoring methods [11]. Rotocopter UA Vs can cover 1–8 hectares per battery charge, while fixed-wing UA Vs can cover 10–40 hectares, depending on the altitude [5]. This ability to rapidly assess large fields allows for frequent monitoring and the acquisition of high-resolution data, which is difficult to achieve with manual ground inspections [1]. Farmers often find it challenging to regularly inspect every part of extensive land holdings, a task that drones can perform effectively through routine aerial surveillance, providing aerial views of their harvest and information on water systems, soil variations, pests, and fungal infestations [1]. Unlike satellite images, which can be obstructed by clouds, UA Vs offer greater reliability, along with freedom from positioning and timing limitations associated with satellite and manned aircraft-based remote sensing [11].

The adoption of UA V technology offers substantial cost-saving benefits for farmers, primarily through the enablement of Variable Rate Technologies (VRT). UA V-collected data facilitates the targeted application of inputs, resulting in significant reductions in resource use [13, 18]. Studies have indicated the potential for fertilizer usage reductions of up to 80% and pesticide use reductions of up to 80% [14]. This precise application, sometimes guided by GPS coordinates in drone systems, not only lowers input costs but also minimizes environmental impact by reducing the overall amount of chemicals used. For example, savings in herbicides have been reported in the range of 20% to 50% through precision application [5, 16, 14].

Moreover, the integration of UA Vs within broader robotic systems and smart machines has shown potential for significant decreases in labor costs (up to 97%) and fuel consumption (up to 50%) for specific agricultural tasks like spraying and fertilization [14]. Some reports suggest that drones can save up to 20 times the labor of farmers [13]. The automation of procedures through digital agricultural technologies (DATs), including UA Vs, streamlines operations and diminishes the discomfort associated with protective clothing worn during manual spraying [14].

Beyond cost reductions, improved yield and better resource management contribute to overall economic benefits for farmers. VRT, enabled by UA V data, has been linked to yield increases of up to 62% [14]. UA Vs equipped with sensors like thermal cameras can also enable efficient utilization of water through targeted irrigation, preventing water wastage [4]. Projects utilizing IoT and satellite data have demonstrated fertilizer cost savings ranging from 5% to 70%, highlighting the potential of data-driven approaches [14]. The comprehensive data provided by UA Vs, when effectively analyzed using techniques like vegetation indices and machine learning, translates into an economic benefit that enhances farmer profitability. In fact, the perceived economic benefit is a significant driver for farmers considering the adoption of drones [4].

In conclusion, the decreasing cost of agricultural-grade UA V systems, coupled with their efficiency in data collection and the accessibility of cloud-based processing, makes them a powerful tool for implementing precision agriculture practices like VRT. These practices directly lead to substantial cost savings for farmers through reduced input usage, potential decreases in labor and fuel, and improved yields, ultimately contributing to enhanced economic sustainability [1, 5].

Research Challenges

While the global success of UA V technologies in agriculture is evident, applying these innovations to Turkey’s unique agricultural landscape brings a number of challenges that must be addressed. One major issue pertains to limited data on UA V technology adoption and its impacts within Turkey. Because UA Vs are relatively recently introduced to Turkish agriculture, there is a noticeable deficiency in terms of localized research and empirical studies that should be pursued regarding the practical benefits and limitations of UA Vs under Turkish farming conditions.

This scarcity of data itself acts as an adoption barrier because many Turkish farmers and policymakers receive relatively few insights regarding how UA Vs can directly affect yield improvement, cost reduction, and resource management within their specific agricultural sectors. More importantly, scaling up the knowledge globally to the local level requires attention to specific problems that farmers in Turkey face with heterogeneous soil types and climate conditions, and crop varieties grown across regions. Other than this data limitation, two big challenges are specialized training and technical capability for flying UA Vs and analyzing generated data. While the technology of UA Vs in and of itself holds tremendous promise, certain relatively complex aspects involved in flying drones and making analyses of high-resolution multispectral images place demands for a level of technical expertise that may not be readily available in Turkish countryside settings. In this regard, the relatively limited availability of experienced UA V operators and data analysts within farming communities in Turkey is likely to dampen the rate of diffusion of this technology.

Besides these, very high upfront costs of UA Vs and continued maintenance and training requirements create financial barriers against their adoption by small and medium-sized farms that do not have the required capital investment in such technology. Overcoming these challenges will involve strategic efforts, including the establishment of local UA V service providers, government incentives to reduce adoption costs, and initiatives to build technical capacity within the workforce in rural areas.

Additional Barriers and Considerations

Other considerations and barriers to UA V implementation involve the cost of training and technical expertise. Mediterranean studies indicate that the ability to process NDVI and other UA V data requires a high degree of technical knowledge on the part of UA V operators and data analysts alike- a resource that may be limited in rural Turkish areas [6].

A developed network of local UA V service providers would make precision agriculture more accessible to Turkish farmers because the individual farms would not need to make investments in expensive equipment and training.

Overall, international experiences underline the transformational role that UA V technology can play in agriculture: from reducing input costs to yield prediction and supporting sustainable farming. A suitably adapted application can henceforth provide the means for UA V-driven precision agriculture to contribute toward attaining environmental sustainability, productivity, and economic resilience in the farming sector of Turkey.

Support Section II (Surveys and Turkey)

Agriculture in Turkey, representing nearly 23% of the country’s total workforce, faces significant challenges related to resource efficiency, environmental sustainability, and adaptation to climate variability [10]. With an average farm size of only 5.9 hectares—considerably smaller than EU (17.4 ha) and US (18.0 ha) averages—Turkish agriculture operates under different structural constraints than more consolidated agricultural systems elsewhere. The Cukurova region, accounting for 5% of Turkey’s total cultivation area with 1,091,000 hectares of cropping land, exemplifies both the potential and challenges of Turkish agriculture [10].

Turkish farming is experiencing transformation pressures from multiple directions, including climate change effects, freshwater supply shortages, and economic pressures from rising input costs like fertilizers [9]. The current agricultural production system faces particular strain as inflation (44.38%) and high interest rates (42.50%) create financial barriers for farm investments [23, 24]. Further, the average interest rate of 46.7% of Turkey from the 1970s to the last decade indicates the long-lasting economic trifle farmers face [22]. These economic conditions make cost-effective technological solutions particularly relevant for Turkish farmers.

Precision farming technologies offer promising solutions specifically tailored to Turkey’s agricultural challenges. Studies demonstrate that variable-rate fertilizer application could achieve fertilizer savings ranging from 4% to 37%, depending on soil variability—a significant consideration given that fertilizer costs currently represent approximately $643.33 per hectare for wheat production [9]. These savings would be particularly impactful in regions with high soil nutrient variability, though implementation potential varies significantly between geographic regions like Central Anatolia and the more diverse Cukurova region.

The economic viability of precision farming in Turkey depends heavily on farm size, with annual equipment costs ranging from $13-131 per hectare (for 500-50 ha farms, respectively). This suggests that while larger operations may readily adopt these technologies, structural adaptations may be necessary for Turkey’s predominantly small-scale farming sector to benefit from precision agriculture advancements [9].

Farmer Readiness and Perceived Benefits

Survey-based research across multiple Turkish provinces provides valuable insights into farmers’ readiness to adopt drone technology and their perceptions of its benefits. In the Southeastern Anatolia Region, a survey conducted between September 2022 and January 2023 with 249 producers in Mardin and Şanlıurfa revealed that 27.7% of respondents had used unmanned aerial vehicles for agricultural purposes in the previous production season. The study found a statistically significant correlation between drone use and education levels (p=0.000), with higher education corresponding to greater adoption rates. The surveyed farms averaged 26.4 hectares, substantially exceeding both the national average of 5.9 hectares and the regional average of 10.4 hectares, with farmers averaging 19.5 years of agricultural experience [4].

Regarding economic benefits, farmers generally recognized the potential advantages of drone technology, with a mean score of 3.497±1.07 on a 5-point Likert scale. Specifically, they acknowledged that drones could increase crop productivity (mean 3.534), reduce work costs (mean 3.426), increase profit (mean 3.438), and be cost-effective (mean 3.590). The perceived usefulness of drones scored even higher at 3.561±1.10, with farmers believing that drones would make their jobs easier (mean 3.598), provide better results than other systems (mean 3.534), enable faster work (mean 3.554), improve work performance (mean 3.554), and allow for work diversification (mean 3.566) [4].

Despite recognizing these benefits, farmers expressed moderate concerns about the technical aspects of drone operation. Statements regarding ease of use received somewhat lower scores, with “I think drones are easy-to-use tools” averaging 3.317 and “It will be easy for me to learn to use a drone” averaging 3.385. Confidence in their ability to use drones was similarly moderate, with statements like “I think using a drone is complicated and difficult” (mean 2.767), “It is difficult for me to use a drone” (mean 2.671), and “I think I am not a farmer who is good at working with digital tools like drones” (mean 2.590) indicating some hesitation. These lower confidence scores likely reflect the prevalence of rental services, where farmers might not directly operate the drones themselves [4].

The research identified two significant factors positively influencing drone adoption intention: perceived usefulness and perceived economic benefit. Interestingly, perceived ease of use and trust attitude did not significantly impact adoption intentions. Farmers were primarily motivated by potential reductions in workload, enhanced productivity, and lower operational expenses rather than by how easy the technology might be to use [4, 7].

High initial investment emerged as the primary barrier to adoption, as evidenced by a survey of 384 farmers in Aydın province. Only 3.12% of these farmers were initially willing to purchase drone technology, while a much larger percentage (32.6%) expressed willingness to rent Autonomous Unmanned Aerial Vehicle (AUA V) technology at an average price of TRY 287.54 per hectare. The significance of this barrier was further confirmed by the 67.2% of farmers who strongly agreed that the high initial purchase cost was a major obstacle to adoption. Notably, when government subsidies were mentioned, potential purchase interest more than tripled to 10.67%; as Parmaksiz and Cinar (2023) note, “Farmers preferred cooperatives as providers of UA V rental services”, highlighting the importance of policy interventions in technology adoption. The study also found that young, technology-oriented farmers with higher agricultural incomes showed greater interest in drone adoption [7].

A complementary survey in the Çukurova region (covering Hatay, Osmaniye, Adana, and Mersin provinces) assessed awareness of precision agriculture (PA) technologies among agricultural stakeholders. While 90.2% of participants (including agricultural engineers, farm equipment dealers, and farmers) reported following new agricultural trends, 51.8% had not heard the term ‘Precision Agriculture’ before. However, after receiving brief training, 97.6% believed PA technologies would benefit Turkish agriculture, 88.4% wanted more detailed training, and 89.7% expressed interest in using these technologies. This dramatic shift in interest after minimal education suggests that knowledge gaps represent a significant but potentially addressable barrier to adoption [10, 3].

Based on these findings, several promising pathways emerge for increasing drone technology adoption in Turkish agriculture. First, given the significant difference between purchase and rental willingness, cooperative-based rental services could significantly accelerate adoption. Second, the tripling of purchase interest when subsidies were mentioned highlights the critical role of government support in overcoming financial barriers. Third, the correlation between education and adoption, along with high interest in training after basic exposure, suggests that educational initiatives could substantially boost adoption rates. Finally, developing favorable borrowing channels specifically designed for agricultural technology investments could help address the initial cost barrier that currently limits widespread adoption [7, 10]

These findings collectively demonstrate that while Turkish farmers recognize the potential efficiency and economic advantages of drone technology, successful widespread adoption will require addressing financial barriers and knowledge gaps through coordinated efforts by government agencies, agricultural cooperatives, and educational institutions. The relatively high willingness to rent suggests a practical intermediate step toward technology integration in Turkish agriculture, particularly if facilitated by appropriate organizational structures and policy frameworks [10, 3].

How UA Vs Address Turkey’s Agricultural Challenges

The agricultural sector in Turkey has long been plagued by resource-wasting and environmentally destructive practices, which have led to issues such as overuse of water, soil degradation, and excessive chemical inputs. Traditional farming techniques, while deeply rooted in the culture, have often failed to adapt to the growing need for sustainability and efficiency. However, the advent of UA V (Unmanned Aerial Vehicle) precision agriculture presents a significant opportunity to address these challenges. UA Vs offer the potential to revolutionize Turkey’s agricultural practices by providing real-time data and insights that can lead to smarter decision-making, increased efficiency, and reduced environmental impact.

Improved Efficiency in Fertilizers and Pesticides

Turkey’s agricultural sector faces challenges related to efficient resource management and increasing productivity. Precision agriculture technologies (PATs) can be considered a tool for farm management that allows the agricultural entrepreneur to optimize inputs and reduce costs [6]. UA V technology can address these challenges by enabling precision application of fertilizers and pesticides, based on site-specific information collected by multispectral and hyperspectral sensors [7]. UA Vs can carry out a wide variety of agricultural operations in support of precision agriculture, including fertilizer application. This targeted approach can help reduce the overuse of agricultural inputs, which is crucial as Turkey has begun to become more foreign-dependent in agriculture. By optimizing the quantity and timing of fertilizer and pesticide applications according to the needs of different areas within a field, UA Vs can contribute to cost reduction and environmental sustainability [12, 7]. For instance, Recording and Mapping Technologies (RMT), which include UA Vs with sensors, can lead to significant fertilizer savings. One study achieved an 80% reduction in fertilizer doses applied in a vineyard through the use of aerial imagery and ground detection. Variable Rate Technologies (VRT), often implemented using UA Vs, have demonstrated the potential for fertilizer savings of up to 59.6%. In one case, a 31% reduction in potassium-based fertilizer and a 59% reduction in phosphate consumption were achieved [14]. Furthermore, regarding pesticides, UA Vs help ensure very precise pesticide spraying, which uses fewer chemicals as the zones are specific in number, minimizing environmental contamination. VRT has shown potential for pesticide savings ranging between 8% and 80%. Sensor-based variable-rate application (VRA) achieved an 8% fungicide savings in winter wheat, and another study reported a 51.9% reduction in spray volume for air-assisted spraying based on real-time disease spot identification. Autonomous robotic systems integrated into modern agricultural practices have also led to substantial Plant Protection Product (PPP) savings, with one system achieving 66% herbicide savings [14, 5, 16]. These precise application methods not only reduce input costs but also contribute to protecting the environment and human health through the controlled use of fertilizers and pesticides [7]. In Turkey, Tekin et.al.’s study examining variable-rate fertilizer application in wheat production suggested that applying fertilizer considering the variations in soil nutrients could be economically justified, with the degree of variability being a key factor [9].

Water Conservation and Irrigation Efficiency

Water scarcity is a significant concern in many agricultural regions, including parts of Turkey. UA Vs equipped with thermal sensors can play a vital role in improving irrigation efficiency and promoting water conservation [7]. By identifying areas experiencing water stress through canopy temperature measurements, farmers can implement variable rate irrigation (VRI), applying water only where and when needed. This precision in irrigation can lead to significant water savings, as demonstrated in international case studies where VRT irrigation systems have achieved water savings of 20% to 50% in vineyards and pear orchards [8, 14]. Recording and Mapping Technologies (RMT) contribute to the necessity of water conservation in agriculture. One study implementing an automatic irrigation scheduling system in an olive orchard, using soil moisture sensor data, resulted in a 24% reduction in water usage. Innovative irrigation scheduling software using model-predicted crop water stress achieved water savings between 16% and 35% [14]. Empirical data from the Precision Crop Management initiative, utilizing IoT sensors, satellite imagery, and drone technology, successfully reduced irrigation costs by 10% in wheat cultivation. Guidance and Controlled Traffic Farming (CTF) technologies have also been linked to water savings, with one study observing water reductions of 13.0% and 9.0% for different crops through precision irrigation in CTF systems. Furthermore, CTF was linked to a 65% increase in rainfall-use efficiency, leading to reduced runoff and water conservation. Variable Rate Technologies (VRT) have also demonstrated potential in significantly reducing water consumption, with computer simulations showing variable water savings up to 26% with optimized specific zone control in center-pivot irrigation. Soil moisture sensor-based irrigation scheduling achieved water savings ranging from 7.5% to 19%, and VRI systems reduced irrigation water use by 8–20% for soybeans and 25% for corn. The HydroSense project in Greece, using VRI in cotton fields, showed 5 to 34% savings in water consumption. These examples highlight the potential for UA V-based technologies to address water scarcity challenges in agriculture, including in regions like Turkey [14].

Environmental Impact on Turkish Agriculture

The detrimental ecological footprint of traditional agricultural practices in Turkey poses significant environmental challenges that demand urgent attention. Unconscious watering, spraying and fertilization methods widely employed across Turkish agricultural regions severely damage ecosystems, contaminate groundwater, and destroy beneficial insects and soil microorganisms [3]. Traditional pesticide application techniques enable these harmful chemicals to permeate the environment, posing risks to human health, with farmers often directly exposed to toxins during manual spraying operations. The risk of pesticide residues and their negative impact on ecosystems represents one of Turkey’s most pressing pollution problems, mirroring similar concerns worldwide [7].

Conventional fertilization approaches in Turkey typically treat agricultural land as homogeneous units, applying standardized amounts of fertilizer without accounting for spatial variability, resulting in substantial environmental degradation. This uncontrolled use of fertilizers and pesticides introduces heavy metals into soil systems, triggering contamination that affects all living organisms and ultimately compromises human health through the food chain [16]. Additionally, unconscious stubble burning practices severely impact groundwater quality and destroy beneficial soil organisms [3]. Traditional agricultural development’s singular focus on increased productivity has historically pushed natural systems beyond sustainable limits, while practices such as deep tillage and vegetation burning alter the living conditions of soil microorganisms, causing deterioration of their environment and decreasing soil biota diversity [7]. These conventional methods have contributed to alarming rates of water resource depletion, soil contamination, and excessive salinization of irrigated lands, leading to significant losses of arable territory [3].

The strategic deployment of drone technology in Turkey’s agricultural landscape offers a promising pathway to reduce environmental harm through precision farming methods. Research indicates that drones can transform conventional agricultural practices by enabling farmers to apply resources with unprecedented accuracy, addressing a fundamental environmental challenge in modern farming [5, 16]. This technological intervention represents a significant advancement in global efforts to balance agricultural productivity with environmental conservation.

Drones equipped with spraying capabilities enable site-specific delivery of pesticides and fertilizers, which substantially reduces overall chemical usage. This precision minimizes residue risks and their negative environmental impacts, addressing a globally recognized concern [8, 9]. Variable rate application (VRT) technology, facilitated by drones, proves essential for environmental sustainability by enabling precise application of water, fertilizers, and pesticides, thereby improving resource efficiency [14].

Research on Digital Agricultural Technologies (DATs) shows that VRT can achieve up to 80% reduction in pesticide use and 60% decrease in fertilizer usage. Additionally, initiatives like the Smart Orchard Spray Application within the IOF2020 project demonstrated significant environmental benefits: 22% to 39% reduction in greenhouse gas emissions through optimized pesticide application, along with 48% reduction in spray drift. Similarly, an autonomous system achieved 66% herbicide savings through precise weed detection and targeted spraying [14].

Another major environmental advantage comes from improved crop health monitoring capabilities. Drones effectively monitor crop health, enabling early detection of diseases, nutrient deficiencies, and water stress [1]. This early detection allows for targeted interventions rather than broad, indiscriminate treatments, potentially reducing the overall need for extensive chemical use. For example, vegetation indices like ExG and VEG, derived from low-cost camera UA V imagery, have achieved high accuracy (83.74–91.99%) in vegetation fraction mapping, demonstrating their potential for precise weed management [8, 5]. Multispectral and hyperspectral sensors on drones can identify changes in crop nutrient status, enabling precision fertilization and preventing over-fertilization and nutrient runoff [5, 16].

Agricultural drones (AUA Vs) are widely recognized as a technology that significantly contributes to sustainable agriculture by reducing input use. This aligns with the global need for policy changes aimed at reducing environmental problems in agriculture. The optimization of input consumption—applying only the required quantities of fertilizer and pesticide—represents a key aspect of this contribution [7, 3].

By enabling more precise farming methods and offering opportunities to optimize inputs and reduce costs, drone technology supports environmentally conscious production. The integration of UA V data with GIS and predictive modeling can further optimize resource usage and enhance crop resilience to stress [8, 4]. A case study of an Italian cereal farm that adopted precision agriculture technologies demonstrated a 53% reduction in pesticides after adoption [6]. These advancements collectively indicate a strong potential for drones to play a crucial role in fostering more sustainable agricultural practices in Turkey.

Farmer Concerns

Turkish farmers face significant economic hurdles when considering new agricultural technologies, particularly agricultural drones (AUA Vs). The high initial investment cost, ranging from USD 15,000 to 25,000, represents a major barrier to adoption, with 67.2% of surveyed farmers citing this as prohibitive. This substantial upfront cost translates to extremely low purchase intention, with only 3.12% of farmers indicating they would consider buying such technology [7]. Beyond the purchase price, farmers worry about ongoing expenses including subscription fees, training costs, maintenance requirements, and eventual replacement costs. These cumulative “adjustment costs” significantly impact the perceived economic viability of new technologies [18]. Without clear evidence of sufficient return on investment and profitability, farmers remain reluctant to make such substantial financial commitments [4]. Farm size also plays a crucial role in technology adoption decisions, with approximately 10.3% of farmers rejecting Precision Agriculture technologies, specifically citing high investment requirements and small field size as significant barriers [10].

Farmers express considerable hesitation regarding the ease of use and practicality of new technologies like drones. Despite acknowledging potential time and cost savings, many remain uncertain about operational aspects such as spraying effectiveness, coverage capabilities, and their own ability to operate drones even after training. Factor analysis reveals that some farmers feel uneasy using new technological tools, consider themselves too old to learn, find the learning process troublesome, and view new technology as an additional burden [7]. The technological complexity of solutions like drones and aircraft/satellite systems has limited their adoption even in more technologically advanced markets like the United States [18]. Interestingly, while approximately half of the surveyed Turkish farmers believed traditional spraying methods were inefficient (47.6%) and potentially harmful to their health (53.4%), they still expressed uncertainty about alternatives [7].

Legal procedures and regulations governing advanced agricultural technologies create additional adoption barriers. Complex or restrictive legal arrangements can impede the implementation of potentially beneficial technologies. In certain regions of Turkey, particularly near the Syrian border, security issues and the presence of signal jammers introduce additional restrictions on drone usage. Farmers must obtain necessary permits regarding flight conditions and adhere to legislation from the General Directorate of Civil Aviation [4, 7]. Data ownership, privacy, and security have emerged as significant concerns in digital agriculture, with ongoing debates centering on farmers’ concerns about ownership of data generated from their fields and potential compensation, alongside data privacy and security considerations [18].

Government intervention could significantly impact adoption rates, with recommendations including incorporating drones into existing state machinery and equipment support programs, providing financial assistance such as interest-free loans for AUA V purchases and extending current agricultural equipment subsidies to cover AUA V technology [7]. For example, in Malaysia, research suggests the government should offer different incentives specifically for rural farmers using advanced technologies like drone cameras [13]. Agricultural cooperatives are identified by Turkish farmers as organizations best positioned to deliver rental services for expensive technologies like drones, potentially accelerating adoption among small and medium-sized operations by leveraging collective farmer funds [7].

TARNET, a technology company affiliated with Agricultural Credit Cooperatives, could play a vital role in facilitating access to AUA V technology by managing subsidy programs or offering affordable rental services [7]. Agricultural extension services can facilitate drone adoption by providing information and guidance, while technology providers increasingly offer cloud-based farm management information systems [18]. Research institutions and industry representatives provide essential evidence about farmers’ technology adoption behaviors, informing policy decisions. The social aspects of technology diffusion—including communication, exhibitions, fairs, and field days—play crucial roles in increasing awareness of new technologies. Developing efficient rental markets represents a viable approach to overcoming high initial purchase costs, especially since most farmers who used drones did so by
renting them [10, 7].

Data Collection Challenges

One of the considerable limitations in this research was the very limited nature of previous studies and case analyses on the adoption of UA Vs in the agricultural sector of Turkey. In contrast to countries where various aspects of UA V technologies have been studied and piloted, there is limited, if any, prior research undertaken within Turkey to fully understand the potential for the technology within a local context. The limited number of case studies and field data restricted the depth and breadth of this research; it was required to rely heavily on international examples or small-scale projects. In this respect, this shortcoming in current localized research reflects a serious requirement for a more extensive research investigation related to the potential of integrating UA Vs within Turkish agriculture.

Moreover, the very process of gaining relevant data was particularly difficult due to the fact that there are no records or organized systems tracking the use of UA Vs within Turkey. This lack of structured data systems made it extremely challenging to assess the current state of UA V implementation or measure its impact across different farming regions. Future research would greatly benefit from the establishment of comprehensive data collection frameworks, such as national registries or cooperative databases, to track UA V utilization and outcomes. Such initiatives would ultimately allow researchers to conduct more powerful analyses in the development of a clear understanding of UA Vs’ potential benefits and challenges within Turkey’s unique agricultural landscape.

Implications for Turkey’s Agricultural Sector

Regardless of the very promising potential, several obstacles stand in the way of this technology being widely used in Turkey’s agricultural sector. A very important factor is that the farmers are not aware, and there is a lack of technical knowledge, especially in the less developed regions. Farmers are skeptical about such technologies being viable; often, they think that it would be too expensive or complicated to use. This is a major knowledge gap, as it prevents farmers from fully grasping how UA Vs could improve productivity by reducing costs. Such problems need awareness campaigns, hands-on training, and demonstration projects that will outline the practical benefits of the technology.

Another major barrier is, of course, the economic one, especially for small-scale farmers who cannot afford the initial costs of the UA Vs or the related services. In this regard, Turkey can introduce government-backed financial incentives, such as subsidies, soft loans, or tax exemptions, to make UA Vs more accessible. Cooperative-led initiatives could also play an important role, whereby farmers are allowed to pool resources and rent UA Vs rather than purchase them outright, reducing the economic burden on individual farmers.

Furthermore, the absence of centralized data systems and extensive research on UA V usage in Turkey represents a barrier to scaling. Without reliable data regarding UA V performance and trends in adoption, it is challenging to develop effective policies or tailor solutions to farmers’ needs. Building national databases and encouraging partnerships between universities, cooperatives, and government bodies could help close this gap and make informed, data-driven decisions to further promote UA V use.

Overcoming these challenges will help Turkey unlock the transformational potential of UA V agriculture. Such technologies can lead to sustainable development through the efficient use of resources, reduction in environmental impact, and enhanced agricultural productivity. With proper support mechanisms, UA Vs could act as an agent of change for modernizing the agricultural sector of Turkey by helping farmers adapt to global challenges with long-term economic and environmental sustainability.

Conclusion

Unmanned Aerial Vehicles (UA Vs) hold a revolutionary capability for the modernization and sustainability of Turkish agriculture. This study has explored the benefits of UA V-based remote sensing technologies in addressing some of the most pressing challenges in Turkey’s agricultural sector, such as over-fertilization, excessive pesticide use, and inefficient resource management. Drawing upon global and local case studies, the findings confirm the critical role UA Vs can play in achieving significant advancements in productivity, cost efficiency, and environmental sustainability.

Utilization of airborne UA V technologies in agriculture has yielded impressive worldwide results because it allows access in real time to high-resolution, spatially detailed data that can be used for precision farming. For example, multispectral and hyperspectral imaging are able to help unlock information about plant health, soil and nutrient availability, and empower Turkish farmers to apply fertilizer and pesticide at the end of their fields. Not only does it decrease the amount of chemical waste, but also this targeted app reduces the environmental pollution, which should be seriously taken into account in areas such as the Konya Plain, where intensive irrigation and fertilizing lead to soil degradation. Additionally, UA Vs equipped with thermal imaging sensors optimize water use by identifying areas of water stress, which is essential for arid regions in Turkey facing water scarcity.

Examples from elsewhere, including the Mediterranean and Australia, showcase the economic and operational benefits of UA V technology. Research has demonstrated pesticide use reductions up to 30% and substantial cost savings via better fertilizer application. For Turkish farmers, these results do so place UA Vs at the forefront of a potential cost reduction by containing or even increasing crop yield. Additionally, pilot projects at local levels in Turkey, encompassing examples of UA V-aided pesticide spraying in paddy fields, have also demonstrated the capacity of the technology to save time, reduce labour costs, and support sustainable farming.

Despite these benefits, several barriers impede the widespread adoption of UA Vs in Turkey. High upfront costs, a lack of technical expertise, and limited awareness about the capabilities of UA Vs are among the most significant challenges. Surveys show that many farmers, especially farmers running small and medium-sized fields, consider UA Vs to be too expensive or too complicated. Moreover, the absence of centralized data systems and empirical studies on UA V adoption within Turkey creates additional obstacles, as farmers and policymakers lack the localized insights necessary to fully understand the technology’s impact.

In order to address these limitations, some strategic efforts should be taken in order to encourage the use of UA V technologies. Specifically, government-sponsored measures like subsidies, interest-free loans, and tax breaks can help alleviate the economic pressure on farmers. Cooperative-based rental services for unmanned air vehicles represent an alternative solution that can be used by farmers to get access to the latest technology with minimal capital outlay. Furthermore, awareness campaigns and hands-on skills programs are crucial in addressing the knowledge gap, especially in rural areas where technical skills are lacking. Such efforts should be supported with the establishment of national databases and research protocols to record UA V applications and results that would provide data-driven decisions regarding the integration of UA Vs in agriculture in Turkey.

In the future term, the application of UA V technology has the promise to turn Turkish agriculture into a model of sustainability and productivity. Through providing precision agriculture capability, UA Vs can alleviate losses of resources, environmental impairment, and yield enhancement, all of which are highly relevant to addressing climate change and the demand for more food in the world. On the other hand, the popularization of UA Vs is compatible with Turkey’s sustainability goals, potentially leading to sustainable long-term economic resilience and environmental protection.

In conclusion, while the road to widespread UA V adoption in Turkey’s agricultural sector is fraught with challenges, the opportunities far outweigh the obstacles. Under the optimal policy environment, along with technological advancement and farmer training, UA Vs may provide disruptive changes to Turkish agriculture, an increase in productivity, sustainability, and competition in the global market. The success stories from other countries and the initial results from local pilot projects provide a clear roadmap for how Turkey can harness the full potential of UA V technology to modernize its agricultural practices and ensure food security for future generations.

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About the author

Alp Yörük

Alp is currently a junior at Robert College in Istanbul, Turkey. He aspires to become an aeronautical engineer and has a deep passion for engineering, drones, and their applications in environmental sustainability. From the past to the present, Alp has never stopped creating; he’s participated in robotics competitions and project development contests that allowed him to bring his ideas to life.

Alp is especially interested in how drone technology can support sustainable agriculture and help unravel global challenges. One day, he hopes to make a meaningful impact on himself, his community, and the world.

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