Gaseous Air Pollutants Research Articles

Efficiency of Air Transport Industry in European Union Nations with Regard to Environmental Factors

Purpose: Evaluating the effectiveness of nations by analyzing the relationship between the outcomes of the aviation sector and the environmental resources associated with these outcomes is essential for policymakers to develop environmental regulations and for managers to take suitable actions. This study aims to evaluate the environmental effectiveness of the airline industry in European Union (EU) member states. Methodology: We assessed the efficiency of data from 26 EU countries using Data Envelopment Analysis. Findings: The study's findings determined that Austria, Luxembourg, Hungary, and Ireland had the lowest efficiency levels. Air pollution and greenhouse gas emissions primarily influence the efficiency of these countries. We identify Germany as the least efficient country, specifically when compared to France and Italy. These findings indicate that, despite the EU's implementation of environmental impact legislation, developed member states have not successfully enforced it. Originality: Previous research has not examined the effectiveness of countries in terms of both passenger and flight volumes, as well as environmental considerations such as air pollution, greenhouse gas emissions, kerosene and jet fuel use, energy products, and overall environmental taxation

A Reinforcement Learning-Based Solution for the Capacitated Electric Vehicle Routing Problem from the Last-Mile Delivery Perspective

The growth of the urban population and the increase in e-commerce activities have resulted in challenges for last-mile delivery. On the other hand, electric vehicles (EVs) have been introduced to last-mile delivery as an alternative to fossil fuel vehicles. Electric vehicles (EVs) not only play a pivotal role in reducing greenhouse gas emissions and air pollution but also contribute significantly to the development of more energy-efficient and environmentally sustainable urban transportation systems. Within these dynamics, the Electric Vehicle Routing Problem (EVRP) has begun to replace the Vehicle Routing Problem (VRP) in last-mile delivery. While classic vehicle routing ignores fueling, both the location of charging stations and charging time should be included in the Electric Vehicle Routing Problem due to the long recharging time. This study addresses the Capacitated EVRP (CEVRP) with a novel Q-learning algorithm. Q-learning is a model-free reinforcement learning algorithm designed to maximize an agent’s cumulative reward over time by selecting optimal actions. Additionally, a new dataset is also published for the EVRP considering field constraints. For the design of the dataset, real geographical positions have been used, located in the province of Eskisehir, Türkiye. It also includes environmental information, such as streets, intersections, and traffic density, unlike classical EVRP datasets. Optimal solutions are obtained for each instance of the EVRP by using the mathematical model. The results of the proposed Q-learning algorithm are compared with the optimal solutions of the presented dataset. Test results show that the proposed algorithm provides remarkable advantages in obtaining routes in a shorter time for EVs.

The Synergy of Pollution and Carbon Reduction by Green Fiscal Policy: A Quasi-Natural Experiment Utilizing a Pilot Program from China’s Comprehensive Demonstration Cities of Energy Conservation and Emission Reduction Fiscal Policy

Using data from 2003 to 2019 for China’s 257 cities, this quantitative research utilizes the difference-in-differences approach to evaluate the synergy of the Comprehensive Demonstration Cities of Energy Conservation and Emission Reduction Fiscal Policy on pollution and carbon reduction. The primary results are as follows. The policy successfully reduces total emissions of industrial SO2, industrial wastewater, and CO2, thus achieving the desired synergistic effect of pollution and carbon reduction. Facilitating green technological innovation and promoting industrial upgrading are the transmission mechanisms through which the synergistic effect of the policy operates. The negative effect of the policy on the total emissions of industrial SO2 and CO2 is greater in the eastern area than in the mid-western area and the impact of the policy on decreasing the total emissions of industrial SO2 is more pronounced in non-resource-based cities compared to resource-based cities. This study provides an empirical reference for green fiscal policy with respect to reducing air pollution, wastewater pollution, and greenhouse gas emissions.

Association between exposure to environmental pollutants and increased oral health risks, a comprehensive review.

The burden of disease and death attributable to environmental pollution is a growing public health challenge worldwide, particularly in developing countries. While the adverse effects of environmental pollution on oral health have garnered increasing attention, a comprehensive and systematic assessment remains lacking. This article delves into the intricate relationship between environmental pollution and oral health, highlighting significant impacts on various aspects such as dental caries, periodontal diseases, oral facial clefts, cancer, as well as other oral diseases. Our results suggested that secondhand smoke, particulate matters (PM) and heavy metals are the most important risk factors affecting oral health. Additional contributors, such as radiation pollutants, electronic cigarette, phthalates, gaseous air pollutants, pesticides, solvents, wood dust, formaldehyde and excessive fluoride were investigated, though evidence for their impacts remains limited and often inconclusive. The review also explores potential mechanisms underlying these impacts, including microorganism, inflammation, oxidative stress, genetic influences, and toxicant exposures from heavy metals and other pollutants. For instance, PM2.5 may contribute to dental caries by disrupting oral pH balance and absorbing heavy metals such as lead and cadmium which have been considered as caries promoting elements. It is also associated with adverse inflammatory responses and tissue damage in periodontal tissues by causing oxidative stress, potentially leading to periodontitis. Drawing on current evidence, it provides a comprehensive analysis of these associations, offering critical insights to guide the development of preventive strategies and public health interventions. The findings highlight the pressing need for future research to validate the causal links between environmental pollution and oral diseases and to unravel the underlying biological mechanisms. Ultimately, greater attention must be directed toward addressing the relationship between environmental pollution and oral diseases, with a focus on pollution control and the reduction of preventable environmental risks to safeguard oral health on a broader scale.

Utilization of refuse-derived fuel in industrial applications: Insights from Uttar Pradesh, India.

Urbanization and population growth in India have quickened, leading to an annual generation of around 62 million tonnes of municipal solid waste (MSW). Improper management of organic waste presents a major environmental problem due to air and water pollution, soil contamination and greenhouse gas production. This research aims to develop refuse-derived fuel (RDF) as a viable option, converting waste into a high-calorific energy carrier for industrial use. The RDF samples were collected from five strategic locations in Uttar Pradesh: Morta Site, Pipeline Site, and Sector 146 Noida, covering various waste compositions found at these landfill sites. Proximate and ultimate analyses of the RDF prepared from these sources were conducted, followed by in-depth Thermogravimetric Analysis (TGA) to validate its suitability as a potential feedstock. Careful waste segregation and treatment for better fuel quality can help minimize the difference in calorific values between different sites. Based on RDF tests, the waste-to-energy technology can divert over 30% of solid waste from landfills and cut greenhouse gas emissions by as much as 25% compared to traditional disposal methods. Unlike RDF, which is part of the replacement line for coal in industrial furnaces such as thermal power plants, it eliminates over 15% and 20% of sulfur dioxide (SO2) and nitrogen oxides (NOx). Ensuring that RDFs support sustainable energy technologies and align with circular economy principles, the study's results could enhance energy efficiency in waste management and complement environmental policy goals across all states in India and worldwide.

Air Pollution and Cognitive Impairment Among the Chinese Elderly Population: An Analysis of the Chinese Longitudinal Healthy Longevity Survey (CLHLS).

Cognitive impairment and dementia have long been recognized as growing public health threats. Studies have found that air pollution is a potential risk factor for dementia, but the literature remains inconclusive. This study aimed to evaluate the association between three major air pollutants (i.e., PM2.5, O3, and NO2) and cognitive impairment among the Chinese elderly population. Study participants were selected from the Chinese Longitudinal Health Longevity Survey (CLHLS) after 2005. We define cognitive impairment as a Chinese Mini-Mental-State Exam (CMMSE) score <24. The associations of air pollution with cognitive impairment and CMMSE score were evaluated with a logistic regression model and a linear mixed-effect model with random intercepts, respectively. A total of 3,887 participants were enrolled in this study. Of the 2,882 participants who completed at least one follow-up visit, 931 eventually developed cognitive impairment. In single-pollutant models, we found that yearly average PM2.5 and NO2 as well as warm season O3, were positively associated with cognitive impairment. NO2 remained positively associated with cognitive impairment in the multi-pollutant model. The linear mixed-effect models revealed that warm season O3 and yearly average NO2 were significantly associated with decreased CMMSE scores. Our research has established a positive association between cognitive impairment and air pollution in China. These findings underscore the imperative for the next iteration of China's Air Pollution Prevention and Control Action Plan to broaden its focus to encompass gaseous air pollutants since mitigating single air pollutant is insufficient to protect the aging population.

Cutting-Edge Nanotechnology Used in Separators of Lithium Battery

As extreme weather events like sandstorms and droughts become increasingly frequent, governments worldwide have acknowledged the urgent need to address ongoing environmental degradation. In response, numerous policies and proposals aimed at preserving the Earth have been rapidly introduced. Among these, the adoption of electric vehicles (EVs) has emerged as a key solution to air pollution and greenhouse gas emissions, with lithium batteries playing a central role in their functionality. To enhance the safety and extend the lifespan of these batteries, separators have been developed, and recently, nanotechnology has been applied to improve their performance. This article explores the role of nanotechnology in advancing lithium battery separators for EVs. It provides an overview of the basic classifications of separators, comparing their respective advantages and disadvantages. Further, the article explores the manufacturing processes of nanoparticles and separators, highlighting how nanotechnology is integrated into separator design. The theoretical principles behind improving the affinity between electrolytes and separators are also analyzed. Finally, the use of separators in lithium-metal batteries is discussed.

Powering Indonesia’s Future: Reviewing the Road to Electric Vehicles Through Infrastructure, Policy, and Economic Growth

Electric vehicles (EVs) emerged as a help for Indonesia as a pathway to address environmental challenges related to air pollution and greenhouse gas emissions from the transportation sector. Despite governmental efforts, including Presidential Regulation No. 55/2019, EV adoption rates in Indonesia remain low, although sales are increasing annually due to limited charging infrastructure, high upfront costs, and consumer perception. This study distinguishes itself from previous research by moving beyond a singular focus on policy, adoption factors, barriers, or economic opportunities. Instead, it integrates these dimensions into a cohesive analysis while placing particular emphasis on government policies. By adopting this multidimensional approach, the study presents a nuanced understanding of EV adoption in Indonesia, exploring not only the drivers, challenges, and economic potential but also the tangible benefits of EV manufacturing and usage for both producers and consumers within the current regulatory framework. It highlights the transformative impacts of EV adoption on key areas such as job creation, GDP expansion, and energy security, offering strategic insights for policymakers, industry leaders, and stakeholders. Future research could explore rural infrastructure development, local battery production impacts, and long-term economic implications of EV in Indonesia’s ecosystem.

Air quality levels in the industrial city of Jubail, Saudi Arabia

Ambient air quality remains a significant health and environmental challenge in developing cities, primarily due to increasing gas emissions from fossil fuel use. Harmful outdoor air pollutants constitute a critical environmental and public health concern, as poor air quality directly impacts human health, leading to respiratory and cardiovascular diseases. This study aimed to assess ambient gaseous air pollutants—specifically sulfur dioxide (SO2), nitric oxide (NO), nitrogen dioxide (NO2), carbon monoxide (CO), and non-methane hydrocarbons (NMHC)—in Jubail Industrial City, Saudi Arabia. Hourly fixed-site air quality monitoring data were collected from three monitoring stations distributed throughout Jubail, covering the period from January 2020 to December 2022, alongside recorded hourly meteorological conditions. Standard monitoring equipment was employed to measure pollutant concentrations at all three locations. Notably, the highest emissions of CO, SO2, and NMHC occurred in 2021, while the highest emissions of NO, NO2, and NOx were recorded in 2022, with 2022 generally exhibiting the highest gas emissions and 2020 the lowest. Variations in gaseous contaminants were observed, influenced by changes in meteorological conditions and human activities. However, the levels of gaseous emissions remained within acceptable limits according to the air quality index. Consequently, policies implemented during and after the COVID-19 lockdown effectively reduced the accumulation of gaseous emissions to below harmful levels. Maintaining these measures is crucial for ensuring ongoing air quality improvements.

Temporal Variation of Particulate and Gaseous Air Pollutants in the Industrialized Region of Kocaeli: Long-term Air Pollution Trend (2019–2023)

Temporal Variation of Particulate and Gaseous Air Pollutants in the Industrialized Region of Kocaeli: Long-term Air Pollution Trend (2019–2023)

Emission reduction strategies and health: a systematic review on the tools and methods to assess co-benefits

ObjectiveThe objective of this study is to review the current literature on the health co-benefits of emission reduction strategies and the methods and tools available to assess them.DesignSystematic review conducted...

Advances in electrochemical treatment for state-of-the-art abatement of gaseous air pollutants: A review

Advances in electrochemical treatment for state-of-the-art abatement of gaseous air pollutants: A review

Economic and Environmental Assessment of Ammonia as a Sustainable Fuel for Tugboat Operations at the Port of Texas

This study assesses the feasibility of ammonia as a sustainable alternative fuel for tugboat operations in the Port of Texas, a major U.S. maritime, oil and gas hub. Tugboats, while critical to port logistics, contribute significantly to localized air pollution and greenhouse gas emissions, impacting both environmental quality and public health in surrounding communities. Given the International Maritime Organization’s (IMO) goals to reduce carbon emissions by 40% by 2030 and 70% by 2050, exploring alternative fuels has become imperative. Ammonia, a carbon-free fuel, presents both opportunities and challenges. While ammonia combustion produces no direct CO₂ emissions, making it attractive from a decarbonization standpoint, its lower energy density results in higher fuel volumes and increased operational costs compared to marine fuel oil (MFO). This paper presents a comparative analysis based on real-world data, mathematical modeling, and emission trade-offs, examining the economic implications, environmental impact, and safety concerns of adopting ammonia as a tugboat fuel. Results indicate that while ammonia could enable significant CO₂ reductions, challenges related to fuel storage, cost, and infrastructure must be addressed. The findings suggest that with appropriate policy support and investment in handling infrastructure, ammonia can become a viable fuel option for sustainable maritime operations.

Environmental Impact of Electrification on Local Public Transport: Preliminary Study

The objective of this study is to provide a comprehensive analysis of the environmental impact of diesel and electric buses, with a focus on pollutant emissions along a mixed urban–rural route in small urban settings. Utilizing a detailed simulation model, this research compares emissions from a diesel bus and an electric bus on a specific route in a small town in central Italy. Key findings reveal that electric buses significantly reduce local exhaust emissions but are not entirely emission-free, considering the full life cycle, including electricity generation. The Well-to-Wheel analysis shows lower CO2 emissions for the electric bus compared with the diesel bus, with a substantial part of the emissions occurring at power generation facilities. Non-exhaust emissions, especially Total Suspended Particles, are similar for both bus types. This study highlights the advantages of adopting electric buses in urban areas to decrease local air pollution and greenhouse gas emissions. However, it also underscores the importance of cleaner electricity generation methods to fully leverage the environmental benefits of electric vehicles. The findings provide valuable insights for decision makers and urban planners in developing sustainable urban transportation systems.

Enhancing the Reliability of NO2 Monitoring Using Low-Cost Sensors by Compensating for Temperature and Humidity Effects

The study investigates methods to enhance the reliability of NO2 monitoring using low-cost electrochemical sensors to measure gaseous pollutants in air by addressing the impacts of temperature and relative humidity. The temperature within a plastic container was controlled using an internal mica heater, an external hot air blower, or cooling packs, while relative humidity was adjusted using glycerine solutions. Findings indicated that the auxiliary electrode signal is susceptible to temperature and moderately affected by relative humidity. In contrast, the working electrode signal is less affected by temperature and relative humidity; however, adjustments are still required to determine gas concentrations accurately. Tests involving on/off cycles showed that the auxiliary electrode signal experiences exponential decay before stabilizing, requiring the exclusion of initial readings during monitoring activities. Additionally, calibration experiments in zero air allowed the determination of the compensation factor nT across different temperatures and humidity levels. These results highlight the importance of compensating for temperature and humidity effects to improve the accuracy and reliability of NO2 measurements using low-cost electrochemical sensors. This refinement makes the calibration applicable across a broader range of environmental conditions. However, the experiments also show a lack of repeatability in the zero air calibration.

Estimation of carbon sequestration potential and air quality impacts of biochar production from straw in China

Aiming to optimize straw resource utilization and to reduce air pollutant and greenhouse gas emissions in China, the environmental benefits of biochar production using straw and utilization need to be assessed. Two biochar production scenarios were studied: centralized production scenario (CPS) utilizing an industrialized production method with advanced air pollution control devices, and decentralized production scenario (DPS) based on a distributed production method of biochar at the village level, compared to an open-burning scenario (OBS). The potential GHG emission reductions under DPS, including the benefit of soil biochar application, were evaluated as 680 Tg CO2-eq yr−1, which was lower than the reductions under CPS (780 Tg CO2-eq yr−1). Although the attentional centralized production method of biochar has more potential environmental benefits, at present the distributed production method is more practical in China due to its convenience, management ease, and lower costs. Modeling on air quality in China showed that in comparison with OBS, DPS could reduce the average monthly PM2.5 concentration of key regions by 19%, and about 190 Tg yr−1 biochar could be produced with 150 Tg C yr−1 sequestered in biochar. Our findings support widespread biochar use in China for improved air quality and climate neutrality.

The Impact of NO2 on Epithelial Barrier Integrity of a Primary Cell-Based Air-Liquid Interface Model of the Nasal Respiratory Epithelium.

Nitrogen dioxide (NO2) is a pervasive gaseous air pollutant with well-documented hazardous effects on health, necessitating precise toxicological characterization. While prior research has primarily focused on lower airway structures, the upper airways, serving as the first line of defense against airborne substances, remain understudied. This study aimed to investigate the functional effects of NO2 exposure alone or in combination with hypoxia as a secondary stimulus on nasal epithelium and elucidate its molecular mechanisms because hypoxia is considered a pathophysiological factor in the onset and persistence of chronic rhinosinusitis, a disease of the upper airways. Air-liquid interface cell cultures derived from primary nasal mucosa cells were utilized as an invitro model, offering a high invitro-in vivo correlation. Our findings demonstrate that NO2 exposure induces malfunction of the epithelial barrier, as evidenced by decreased transepithelial electrical resistance and increased fluorescein isothiocyanate (FITC)-dextran permeability. mRNA expression analysis revealed a significant increase in IL-6 and IL-8 expressions following NO2. Reduced mRNA expression of the tight junction component occludin was identified as a structural correlate of the damaged epithelial barrier. Notably, hypoxic conditions alone did not alter epithelial barrier integrity. These findings provide information on the harmful effects of NO2 exposure on the human nasal epithelium, including compromised barrier integrity and induction of inflammatory responses. Overall, this study contributes to our understanding of pathophysiological mechanisms underlying also upper airway respiratory diseases associated with air pollution exposure and emphasizes the importance of mitigating NO2 emissions to safeguard respiratory health.

Synergistic Emission Reduction of Carbon Dioxide and Atmospheric Pollutants Under Different Low-carbon Development Scenarios of the Power Industry in Jiangsu Province

The power industry is the main source of carbon dioxide （CO2） emissions in Jiangsu Province and also an important source of sulfur dioxide （SO2）, nitrogen oxides （NOx）, and particulate matter （PM）. In order to address climate change and contribute to the goal of "carbon peaking and carbon neutrality," Jiangsu Province has implemented a series of low-carbon development policies in the power industry. These policies not only reduce carbon emissions but also have important synergistic emission reduction benefits for atmospheric pollutants. Based on the low-carbon development plan for electricity in Jiangsu Province, a baseline scenario （BAU） and four low-carbon development scenarios have been constructed： current policy scenario （CLE）, IEA target scenario （IEA）, accelerated coal-fired power phaseout scenario 1 （STE1）, and scenario 2 （STE2）. An econometric model was used to predict the future electricity demand in Jiangsu Province, and the greenhouse gas-air pollution interactions and synergies （GAINS） model was employed to quantitatively analyze the impact of low-carbon policies in the power sector on the emissions of CO2, SO2, NOx, and PM, which are the major air pollutants in the region. The results showed that the electricity demand in Jiangsu Province has been increasing year by year, with an annual growth rate of approximately 4.01%. Under the BAU scenario, carbon emissions were projected to peak around 2030, with a peak carbon emission level of 462.03 Mt. Under the IEA scenario, it should reach its peak around 2028, with a peak emission level of 380.27 Mt. Under the CLE scenario, the peak would be expected to occur around 2026 at 353.46 Mt. In both STE1 and STE2 scenarios, carbon emissions had reached their peak and were continuously declining after 2020. In all scenarios, the replacement of conventional coal-fired power plants with natural gas （GAS）, nuclear power （NUC）, solar photovoltaic （SPV）, and wind power （WND） showed high synergistic benefits in pollution reduction and carbon reduction. The deployment of biomass energy （OS1） and non-renewable waste energy （OS2） will result in a significant increase in SO2 emissions. Carbon capture and storage （CCS） transformation of coal-fired power only showed significant synergistic benefits after 2035. The development of OS1 and OS2 fuel substitutes in power plants should focus more on reducing SO2 emissions, while upgrading and retrofitting CCS technology should prioritize the reduction of particulate matter emissions. The research findings provide a reference and decision-making basis for the synergistic efficiency of pollution reduction and carbon reduction in the power industry in Jiangsu Province.

An Experimental Study on the Effect of Nano Zinc Oxide on Reflective Coatings and Building Roof Temperatures

Most roofs on Earth are made of dark materials. Dark roof surfaces can retain heat better than light ones; in Iraq, summer time temperatures on the roofs of dark buildings reached 70–80 degrees Celsius in July and August. The effects of this temperature rise are detrimental to cooling and energy consumption. To lessen heat transfer into the building, use reflective surfaces that can reflect infrared radiation waves. Cool roofs have both short-term and long-term advantages. They can reduce a building's annual air conditioning energy consumption by up to 15%, extend the life of the roof and its service life, improve the energy efficiency of roofs particularly those with inadequate insulation at the front of the roof improve thermal comfort in buildings without air conditioning, and lower greenhouse gas emissions and air pollution. Solar heat is one of the main factors affecting the durability of roofing membranes, according to research and real-world experience with the deterioration of these materials over time. High solar reflectance materials can reflect more sunlight and maintain their coolness in the sun. This study examines a low-cost composite cool coating that uses 60% calcium carbonate and demonstrates a 15°C drop in surface concrete temperature for roof buildings when compared to an uncoated surface. Additionally, compared to 30%wt CaCO3, the effect of 60%CaCO3 in composite coating reduces adhesion strength. According to the study, the weight of CaCO3 in the composite coating increases while adhesion strength, surface roughness, and particle homogeneity distribution decrease. Conversely, the maximum weight of CaCO360% weight percent exhibits good IR reflectance and less tribological properties. While preserving good infrared reflectance, adding 10% ZnO to the coating solution (60% CaCO3/PVac) improves tribological properties. The adhesion strength of the 60% calcium carbonate polymer composite paint increased from 10.9 MPa to 40.2 MPa when the nanomaterial was present, while this material maintained the superior optical qualities of infrared reflection. The coefficient of thermal expansion varies between concrete and coating solutions. For instance, the coating that has 10% weight added ZnO has a peel resistance coefficient of 8*10-6 1/K. The 60%CaCO3/10%ZnO/PVac coating effectively lowers the temperature by 15–12 °C when applied to a building roof.

Estimating monthly NO2, O3, and SO2 concentrations via an ensemble three-stage procedure with downscaled satellite remote sensing data and ground measurements

The gaseous air pollutants nitrogen dioxide (NO2), ozone (O3), and sulfur dioxide (SO2), in addition to particulate matter (PM2.5), are known to be associated with many adverse health effects. However, exposure estimates may not be available in rural or mountainous areas without monitoring stations. In this study, we retrieved satellite remote sensing data for NO2, O3, and SO2 from the Ozone Monitoring Instrument (OMI) L3 products. Together with ground measurements (air monitoring stations and meteorological and land use data), we estimated the monthly NO2, O3, and SO2 concentrations with a spatial resolution of 3×3 km across Taiwan from 2005 to 2019. A three-stage estimation procedure was utilized: in Stage 1, an ensemble generalized additive model (GAM) and machine learning method were used to determine the spatiotemporal variations; in Stage 2, the remote sensing data were downscaled; and in Stage 3, the downscaled concentrations were reused in the Stage 1 procedure for fine-tuning estimations. We obtained overall leave-one-out cross-validation (LOOCV) R2 values ranging from 0.927–0.950, 0.704–0.721, and 0.601–0.716, and root-mean-square-errors (RMSEs) ranging from 1.59–2.28, 3.81–4.18, and 0.67–1.32 ppb for NO2, O3, and SO2, respectively, via the random forest procedure. The annual NO2 and SO2 concentrations greatly improved from 2005–2019, especially in the western residential area of Taiwan. However, despite these improvements in air quality, the annual O3 concentrations tended to increase from 2015–2019. This might be due to the complex mixtures of precursors (e.g., NO2), atmospheric circulation, barriers of the Central Mountain Ridge, and increasing ground temperatures over the past decade. The proposed multistage estimation procedure performed well over the whole island with complex terrain and topography. The study outcomes may provide epidemiological information for long-term ambient exposure estimates and guidance for future administrative policies.