Pollution Control Policies Research Articles

The Role of Energy Policies for Air Pollution Control in the Po Valley

This paper examines the use of integrated assessment modelling to select policies aimed at reducing air pollution in response to growing concerns about the deterioration of air quality, especially in highly populated and industrialized areas. The study focuses on the Po Valley region in northern Italy, renowned for its intricate environmental difficulties arising from industrial operations, extensive farming, and topographic characteristics. The goal of the multi-objective decision problem is to find the best plans for reducing emissions that will minimize the average annual concentrations of PM2.5 while also considering the costs of putting these plans into action and incorporating end-of-pipe, energy, and fuel switch measures. Results highlight the trade-offs between air quality improvement and associated costs, presenting a Pareto curve of optimal solutions.

Synergizing policies for carbon reduction, energy transition and pollution control: Evidence from Chinese power generation industry

To mitigate climate change and achieve sustainable development, Chinese governments have introduced “1+N” “dual-carbon” policy system aimed at reducing CO2 emissions, transforming energy structures and controlling pollution. An effective policy mix and synergy is crucial for achieving the emission reduction targets and for ensuring the effectiveness of the policies, and it is therefore of great practical importance to provide a pathway for policy synergy based on assessing policy effectiveness. This paper selects three policies, namely the carbon Emission Trading System (ETS), Coal Control and Clean Utilization (CCCU), and Green Financial Reform and Innovation Pilot Zone (GFPZ), sets up ten scenarios, adopts difference-in-differences (DID) models to evaluate the impact, and give a pathway for policy synergy. The results show that ETS, CCCU, and GFPZ policies have significant positive effects on carbon emission reduction, energy structure transformation, and industrial environmental pollution control, respectively; CCCU has synergistic effects with ETS and GFPZ policies in controlling coal consumption and increasing the completion of industrial pollution control investments, respectively; while GFPZ policies have conflicting effects with CCCU and ETS in reducing carbon emissions and coal consumption, the GFPZ policy has conflicting effects with CCCU and ETS in reducing carbon emissions and controlling coal consumption. Finally, the study proposes a phased policy support system around carbon emission reduction in the power generation industry, energy structure transformation, and industrial environmental pollution control before 2030 and from 2030 to 2060.

A 150 years record of polycyclic aromatic compounds in the Sihailongwan Maar Lake, Northeast China: impacts of socio-economic developments and pollution control.

The geochemical composition of sediment cores can serve as a proxy for reconstructing past human and nature-driven environmental and climatic changes. We investigated the temporal variation in the concentrations and fluxes of polycyclic aromatic compounds (PACs) which include polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs, and azaarenes in the Sihailongwan Maar Lake and found that they remained low before 1950. The PAC concentrations and fluxes increased substantially since 1950, which was in good agreement with the fast socio-economic development, industrialization, and associated growth in fossil fuel consumption in China, particularly since the 1980s. After 2010, the PAC fluxes decreased, which was consistent with the implementation of air pollution control policies in China at that time. The concentration ratios of the sums of low to high molecular weight PAHs (LMW-PAHs/HMW-PAHs), benzo[e]pyrene/benzo[a]pyrene, and benzo[a]anthracene-7,12-dione/benzo[a]anthracene all decreased from bottom to top of the sediment core, reflecting the rapidly increasing contribution of emissions derived from high-temperature fossil fuel combustion (energy, transport and industry) to the PAC emissions in recent times at the expense of biomass burning. In addition, these data reflect the increasing local sources of PACs in more recent times because of the enhanced human activities in the area surrounding the Maar lake. Our results demonstrate that PAC fluxes and concentrations in sediment cores reflect the regional and national economic development and the efficiency of pollution control measures.

Research on coordination mechanism of public management of soil pollution control policy

Research on coordination mechanism of public management of soil pollution control policy

Research on the spatial and temporal patterns of ozone concentration and population health effects in the Central Plains Urban Agglomeration from 2017 to 2020.

Fine particulate matter (PM2.5) and near-surface ozone (O3) are the main atmospheric pollutants in China. Long-term exposure to high ozone concentrations adversely affects human health. It is of great significance to systematically analyze the spatiotemporal evolution mechanism and health effects of ozone pollution. Based on the ozone data of 91 monitoring stations in the Central Plains Urban Agglomeration from 2017 to 2020, the research used Kriging method and spatial autocorrelation analysis to investigate the spatiotemporal variations of ozone concentration. Additionally, the study assessed the health effects of ozone on the population using the population exposure risk model and exposure-response relationship model. The results indicated that: (1) The number of premature deaths caused by ozone pollution in the warm season were 37,053 at 95% confidence interval (95% CI: 28,190-45,930) in 2017, 37,685 (95% CI: 28,669-46,713) in 2018, and 37,655 (95% CI: 28,647-46,676) in 2019. (2) The ozone concentration of the Central Plains urban agglomeration showed a decreasing trend throughout the year and during the warm season from 2017 to 2020, there are two peaks monthly, one is June, and the other is September. (3) In the warm season, the high-risk areas of population exposure to ozone in the Central Plains Urban Agglomeration were mainly concentrated in urban areas. In general, the population exposure risk of the south is lower than that of the north. The number of premature deaths attributed to ozone concentration during the warm season has decreased, but some southern cities such as Xinyang and Zhumadian have also seen an increase in premature deaths. China has achieved significant results in air pollution control, but in areas with high ozone concentrations and high population density, the health burden caused by air pollution remains heavy, and stricter air pollution control policies need to be implemented.

Adaptive Governance or Status Quo? Unpacking the City of Jakarta's Approach to the Air Pollution Control Program

In recent years, Jakarta has experienced an increase in air pollution which has the potential to have a significant impact on Jakarta residents not only in terms of health, but socio-cultural and productivity. This encourages the need for effective governance strategies to overcome air pollution problems. This study seeks to critically analyze the approach used by the city of Jakarta in dealing with air pollution to find out whether the city of Jakarta's air pollution control policy has led to innovative, flexible and adaptive governance, or is still more inclined towards maintaining the status quo. Based on qualitative data, including in-depth interviews, policy analysis, and consultation with stakeholders, this research examines Jakarta's policy mechanisms, community participation pathways, and inter-agency coordination in controlling air quality and dealing with pollution. The research results show a lack of alignment between progressive policy frameworks and implementation challenges, thus underscoring the need for a more adaptive and dynamic approach. The approach adopted in Jakarta appears to be dominated by a top-down, government-led model, where policies and decisions are primarily formulated and implemented with minimal participation from non-governmental institutions. Such models, while ensuring efficient decision making, may exclude valuable insights of other stakeholders and hinder innovative and context-specific solutions. Additionally, these rigid structures appear to lack the flexibility and responsiveness that are hallmarks of adaptive governance, potentially reducing cities' ability to effectively address air pollution challenges. This research underscores the need for a more inclusive and adaptive governance framework in managing air pollution in Jakarta.

UNRAVELING COMORBIDITY PREVALENCE AND PM2.5 EXPOSURE AMONG MIDDLE-AGED AND ELDERLY: A SPATIAL-TEMPORAL ANALYSIS

Abstract Objective This study describes regional differences and dynamic changes in the prevalence of comorbidities among middle-aged and elderly people with chronic diseases (PCMC) in China from 2011-2018, and explores distribution patterns and the relationship between PM2.5 and PCMC, aiming to provide data support for regional prevention and control measures for chronic disease comorbidities in China. Methods This study utilized CHARLS follow-up data for ≥45-year-old individuals from 2011, 2013, 2015, and 2018 as research subjects. Missing values were filled using the random forest machine learning method. PCMC spatial clustering investigated using spatial autocorrelation methods. The relationship between macro factors and PCMC was examined using Geographically and Temporally Weighted Regression, Ordinary Linear Regression, and Geographically Weighted Regression. Results PCMC in China showing a decreasing trend. Hotspots of PCMC appeared mainly in western and northern provinces, while cold spots were in southeastern coastal provinces. PM2.5 content was a risk factor for PCMC, the range of influence expanded from the southeastern coastal areas to inland areas, and the magnitude of influence decreased from the southeastern coastal areas to inland areas. Conclusion PM2.5 content, as a risk factor, should be given special attention, taking into account regional factors. In the future, policy-makers should develop stricter air pollution control policies based on different regional economic, demographic, and geographic factors, while promoting public education, increasing public transportation, and urban green coverage.

Heterogeneity in shadow prices of water pollutants: A study of the seafood processing industry in Vietnam

Water pollution poses a critical challenge, especially in fast-growing regions, with profound implications for human well-being. Marginal abatement cost (MAC) estimation is crucial for designing efficient water pollution control policies. This study applied the directional distance function to estimate MACs for three water pollutants (Biochemical Oxygen Demand, Chemical Oxygen Demand, and Total Suspended Solids) within Vietnam's seafood processing industry. Additionally, the paper conducted a regression analysis to investigate the determinants of these MACs, utilizing primary data from 116 seafood processing plants in the Mekong River Delta. The median MACs for Biochemical Oxygen Demand, Chemical Oxygen Demand, and Total Suspended Solids were 2451 US$/ton, 3983 US$/ton, and 5519 US$/ton, respectively. The results revealed substantial MAC heterogeneity. Capital-intensive firms, less labor-intensive entities, those with a more complex ownership structure, entities not situated along the seashore or riverside, export-oriented firms, and those demonstrating higher compliance exhibited consistently lower MACs for the three water pollutants. These findings challenge the efficiency of uniform standards or environmental fees in controlling pollution, suggesting that a tradable permit system could offer a more cost-saving alternative.

A comprehensive attribution analysis of PM2.5 in typical industrial cities during the winter of 2016–2018: Effect of meteorology and emission reduction

The frequent occurrence of air pollution in winter has aroused widespread concern. Identifying the detailed source composition of PM2.5 and assessing the reduction effects of different emission sources are crucial steps in improving pollution levels. In this study, we conducted a comprehensive evaluation of emission source reductions, encompassing ten local and ten regional sources. Furthermore, we analyzed the influence of meteorological changes on the abatement of PM2.5 in Tangshan, Shijiazhuang, Xingtai, and Handan during the winter period from 2016 to 2018. Our findings indicate that, in comparison to the winter of 2016, there were significant decreases in the average concentrations of PM2.5 during the winter of 2017. These decreases were attributed to favorable meteorological conditions and emission reductions. However, during the winter of 2018, there was a rebound in PM2.5 concentrations for all four cities. This rebound was primarily caused by adverse meteorological diffusion conditions. Throughout the entire research period spanning from the winter of 2016 to 2018, emission reduction played a significant role in PM2.5 abatement, contributing to 68% in Tangshan, 87% in Shijiazhuang, 93% in Xingtai, and 96% in Handan, respectively. The source apportionment analysis revealed that industrial and residential sources were the dominant contributors to PM2.5 concentrations in the cities. These findings not only confirm the effectiveness of existing industrial and residential pollution control policies but also highlight the imperative need for implementing non-point source control and joint control measures for regional elevated sources in the future.

Do command‐and‐control environmental regulations realize the win‐win of “pollution reduction” and “efficiency improvement” for enterprises? Evidence from China

AbstractWe use the DID method to estimate whether the binding pollution control policy can achieve both “pollution reduction” and “efficiency enhancement” for industrial enterprises after implementing this command‐and‐control environmental regulation of the eleventh Five‐Year Plan in China. We also analyze its influence mechanism in detail. It has been shown that (1) Constrained by binding pollution control policies, enterprises could reduce their pollutant emissions but simultaneously suppress their total factor productivity (TFP), which indicates that command‐and‐control environmental regulations do not achieve both “pollution reduction” and “efficiency gains” for firms. (2) The mechanism analysis shows that under the constraint of the binding pollution control policy, enterprises increase the pollution treatment at the front end of production, such as investment in environmental protection facilities, and adjust the production schedule, such as pollution treatment at the end of production. These pollution treatment measures reduce pollutant emissions while bringing “compliance costs” to enterprises. However, the “innovation compensation effect” fails to compensate for the “compliance cost” brought by pollution control. (3) Further study finds that the binding pollution control policy effectively reduces the pollutant emissions of enterprises with low financing constraints.

Structural equation modeling of the combined effect of urban population, gross regional product and area on air pollution in selected Chinese cities

Expansion of urban scale, including the growth of population, gross regional product and city area, have led to an increase in the city's air pollution. Previous research has often emphasized the adverse effect of urban scale on air pollution levels through the expansion of residents' activities. However, the expansion of urban scale can also induce the green technological innovation and change in the industry structure via the effect of agglomeration, thus leading to reduction of air pollution to some extent. Association mechanisms between urban scale and air pollution are complex and poorly understood. In this context, this study aims to identify the combined effects of urban scale on air pollution through residents' activities, industry structure and technique impact in 292 selected Chinese cities from 2015 to 2020, using the structural equation modeling. Results suggested that the expansion of urban scale had a positive impact on air pollution levels through residents' activities (average impact coefficient: 0.509). But urban scale promoted the impact of green technological innovation and optimization in the industry structure, causing a decrease in air pollution levels. The average impact coefficients of urban scale on air pollution levels through technique impact and industry structure were −0.202 and −0.018, respectively. Furthermore, the multiple-group analysis found that with the growth of urban population, there was an increase in the association strength of urban scale on air pollution via technique impact, while there was a great deal of difference for the industry structure. Findings from this study can contribute to a more comprehensive understanding of the impact of urban scale on air pollution, which will provide a theoretical basis for air pollution prevention and control policies.

Is air pollution joint prevention and control effective in China-evidence from "Air Pollution Prevention and Control Action Plan".

This paper examined the effect of air pollution joint prevention and control on pollution emissions in China. Specifically, based on the panel data of 290 cities from 2007 to 2021, taking the implementation of the "Air Pollution Prevention and Control Action Plan" as a natural experiment, the difference-in-difference-in-difference (DDD) model was used to explore the effect of air pollution joint prevention and control on haze pollution. Results show that air pollution joint prevention has a significant impact on pollutant emissions either as a whole or as a single pollutant. In terms of individual urban agglomeration, whether the Yangtze River Delta or the Pearl River Delta urban agglomerations, the air pollution joint prevention and control policy has a significant impact not only on the overall reduction of pollutant emissions but also on the reduction of single PM2.5 or industrial sulfur dioxide emissions alone. Environmental regulations have also achieved the effect of haze control in general and have a significant impact on the reduction of PM2.5 or industrial sulfur dioxide emissions. Environmental regulations also significantly reduced PM2.5 emissions in these three urban agglomerations. These findings provide a scientific basis and essential reference for understanding the implementation effect of regional joint prevention and control policies comprehensively and objectively.

Comprehensive Evaluation of Spatial Distribution and Temporal Trend of NO2, SO2 and AOD Using Satellite Observations over South and East Asia from 2011 to 2021

The past decade has witnessed remarkable economic development, marked by rapid industrialization and urbanization across Asian regions. This surge in economic activity has led to significant emissions, resulting in alarming levels of air pollution. Our study comprehensively assessed the spatial and temporal trends of key pollutants, namely nitrogen dioxide (NO2), sulfur dioxide (SO2), and aerosol (using aerosol optical depth (AOD) at 550 nm as an indicator), from 2011 to 2021. The data sources utilized include OMI onboard the Aura satellite for NO2 and SO2, as well as MODIS onboard Terra and Aqua satellites for AOD. The results from spatial and temporal trend analyses of the three parameters show that there is a clear declining trend over China and Republic of Korea (e.g., NO2 is declining with an overall rate of −7.8 × 1012 molecules/cm2/year over China) due to the strict implementation of air pollution control policies. However, it is essential to note that both countries still grapple with substantial pollution levels, with proportions exceeding 0.5, indicating that air quality is improving but has not yet reached a safe threshold. In contrast, South Asian regions, including Bangladesh, Pakistan, and India, are experiencing an increasing trend (e.g., NO2 is increasing with an overall rate of 1.2 × 1012 molecules/cm2/year in Bangladesh), primarily due to the lack of rigorous air pollution control policies. The average emissions of NO2 and SO2 were remarkably higher in winter than in summer. Notably, the identified hotspots are statistically significant and predominantly coincide with densely populated areas, such as the North China Plain (NCP). Furthermore, this study underscores the pivotal role of sector-wise emissions in air quality monitoring and improvement. Different cities are primarily influenced by emissions from specific sectors, emphasizing the need for targeted pollution control measures. The findings presented in this research contribute valuable insights to the air quality monitoring and improvement efforts in East and South Asian regions.

Traceability of atmospheric ammonia in a suburban area of the Beijing-Tianjin-Hebei region

Ammonia (NH3) is one of the most important sources that have been linked to the formation of PM2.5. Therefore, it is important to study the source contributions to atmospheric NH3 for air pollution control. Here we used 15N natural abundance (expressed by δ15N) values to quantify the source contributions to atmospheric NH3 in the Beijing-Tianjin-Hebei (BTH) region, which suffers from the country's worst air pollution. Results showed that from 2017 to 2019, the annual mean δ15N-NH3 value at the livestock site (−27.5 ± 6.0 ‰) was lower than at cropland (−20.7 ± 6.0 ‰) and rural residential sites (−22.1 ± 7.4 ‰), while their concentrations were the opposite. Seasonal mean δ15N-NH3 values were the highest in winter and lowest in summer, whereas monthly mean δ15N-NH3 values were the highest in January and lowest in June. The isotope mixing model results showed that agricultural sources account for 64.5 ± 13.5 % of year-round total NH3 emissions, while industrial and other sources contributed 27.4 and 8.1 %, respectively. However, the contribution of industrial sources was higher than that of agricultural sources in January. Our results indicated that the contribution of agricultural sources has decreased after the implementation of air pollution control policies in this region suggesting that NH3 abatement from agricultural sources is effective. However, further refinement of agricultural emission abatement measures will be required, accompanied by a greater focus on controlling winter non-agricultural sources.

High-precision spatio-temporal variations and future perspectives of multiple air pollutant emissions from Chinese biomass-fired industrial boilers

Biomass-fired industrial boilers (BFIBs) are one of the neglected and important anthropogenic sources of air pollutants. A comprehensive boiler-based emission inventory of multiple air pollutants from BFIBs in China in 2020 was first developed based on the activity level database and updated emission factors. Results showed that national emissions of air pollutants from BFIBs in 2020 were estimated to be 11.5 kt of PM, 10.8 kt of PM10, 7.4 kt of PM2.5, 40.5 kt of SO2, 79.8 kt of NOx, 4.2 kt of organic carbon (OC), 1.0 kt of elemental carbon (EC), 31.7 kt of nonmethane volatile organic compounds (NMVOCs), 15.9 kt of NH3, and 116.5 t of five trace metals (Hg, Cr, Cd, Pb, and As), respectively. Air pollutant emissions exhibited significant spatio-temporal heterogeneity. Monthly air pollutant emissions varied by geographical division due to the combined effects of industrial production and winter heating demand. These emissions were mainly concentrated in the eastern coastal region, with Guangdong, Guangxi, Fujian, Jiangsu, and Zhejiang being the five provinces having the highest emissions. In addition, scenario predictions indicate that as the pollution and carbon reduction strategy is implemented, air pollutant emissions from BFIBs in China could become well controlled, with PM, NOx, SO2, and Hg emissions in 2050 projected to be 3.0–8.3 kt, 36.5–75.7 kt, 16.2–32.8 kt, and 0.52–0.87 t, respectively. Our results can provide a highly spatio-temporal resolution inventory of multiple air pollutant emissions from BFIBs for air quality modelling and support the formulation of air pollution control policies for biomass fuel utilization in the context of the pollution and carbon reduction strategy.

Evaluation of Endoparasites in <i>Oreochromis aureus, Amia calva</i> and <i>Clarias gariepinus</i>, in Ase River, Delta State, Nigeria

Parasites constitute a major problem for fish health and their prevalence hamper fish growth and productivity by increasing their morbidity and mortality. Fish endoparasites are often associated with zoonotic disease in humans. The aim of this study was to determine the endoparasitic prevalence and feeding habits of Oreochromis aureus, Amia calva and Clarias gariepinus, in Ase River, Delta State, Nigeria. Atotal of 104 fish comprising of 40 O. aureus, 21 A. calva and 43 C. gariepinus were collected from seven locations of the river during dry and wet seasons, for parasitological investigations. The livers, gills, muscles, small and large intestines of fish specimens were examined, and the sex determination was done by physical observation of the genital papilla, which appeared long in males and reddish round in females. From the specimens, 96 (92.3%) had 191 overall endoparasitic loads. The highest and lowest percentage abundance of 51.18% and 13.08% were recorded in Locations 1 and 4 had respectively. Of the 96 infected fish, 29 (29.8%) were male and 68 (70.1%) female, indicating a much higher infection rate in females. On prevalence abundance across species, A. calva was highest with 21(100%). C. gariepinus was 40 (93.0%) and O. aureus was least with 35(87.5%). The study also identified a total of 21 endoparasites in five taxonomic groups; Protozoans (32.46%), Nematode (38.74%), Annelid (3.66%), Trematode (15.70%) and Cestode (9.42%). The mean intensity of parasitic load showed 58.6, 37.0 and 31.6 to be moderately, highly and slightly affected. ANOVA result on prevalence indicated a significant distribution of endoparasites across specimens (P<0.05; P=0.001). Considering the effect of parasites on fish morbidity and mortality, human food-borne zoonoses, there is need for the communities and industries on the riverbank to adopt right policies for water pollution control.

Analysis of the spatial and temporal distribution characteristics of AOD in typical industrial cities in northwest China and the influence of meteorological factors

The spatiotemporal distribution characteristics of AOD in Lanzhou City over the past decade, as well as the influence of meteorological factors, were analyzed using the MODIS MCD19A2 dataset from 2011 to 2022. Spatial Distribution: The annual average AOD in the study area was found to be 0.278. High AOD values were observed in the main urban area and surrounding low-altitude regions, while low AOD values were observed in the high-altitude mountainous areas in the northwest and southeast. The main urban area exhibited significantly higher AOD levels compared to the three surrounding counties. Temporal Trends: Influenced by air pollution control policies, the AOD in Lanzhou City started decreasing notably from 2014, with a total decrease of −27.18%. The overall trend displayed fluctuations and a downward pattern. The seasonal variation of AOD in Lanzhou City was evident, with the order of magnitude being spring > winter > autumn > summer. The AOD in Yuzhong County was particularly high in spring. There is spatial heterogeneity in the impact of meteorological factors on AOD in Lanzhou. Temperature exhibits greater significance in the central part of Lanzhou, while precipitation shows greater significance in the eastern part of the city, and wind speed is notably significant in the western and eastern parts of Lanzhou. Temperature, relative humidity, and wind speed are positively correlated with AOD, while precipitation and atmospheric pressure are negatively correlated with AOD. Three primary sets of interacting factors were identified: temperature and wind speed, temperature and relative humidity, and temperature and precipitation.

Assessing transboundary air pollution and joint prevention control policies: evidence from China

This study addresses the pressing issue of transboundary air pollution, an environmental concern characterised by the dispersion of pollutants across administrative boundaries. Prior research in this area has lacked an in-depth examination of the efficacy of cooperative environmental policies in managing this challenge. To address this gap, our study first evaluates transboundary sulphur dioxide pollution across 31 provinces in China from 2005 to 2020 utilising the Hybrid Single-Particle Lagrangian Integrated Trajectory model. Following this, we apply a staggered Difference-in-Difference model to gauge the impact of the joint air pollution prevention and control policies adopted by China for high-priority provinces. Our analysis revealed an imbalance in emissions and transboundary pollution levels across provinces. Provinces such as Shandong, Shanxi, and Tianjin face the most severe transboundary SO2 pollution, whereas the highest SO2 emissions were noted in Shandong, Inner Mongolia, and Hebei. The implementation of the joint pollution prevention and control policy resulted in a significant reduction in SO2 emissions and transboundary SO2 pollution by factors of 10.60 and 9.70, respectively, when compared to other provinces. These findings provide valuable insights for shaping environmental cooperation policies and identifying priority provinces for mitigating air pollution.

Influence of anthropogenic activities and loess dusts on the rainwater hydrochemistry in the Chinese Loess Plateau

Rainwater hydrochemistry is an important indicator for tracing anthropogenic input on air quality. As the fastest economically developing city in the northwestern China and the Chinese Loess Plateau, rainwater chemistry, sources of dissolved solutes, and the influence of loess dust on rainwater chemistry in Xi'an city is unclear. Inorganic ions, δD and δ18O of two years' rainwater samples were measured to decipher the above issues. Rainwater samples were weakly alkaline (pH = 7.2) with the mean total dissolved solids (TDS) values of 43 mg/L. NH4+ and Ca2+ dominated in the cations and SO42− and NO3− dominated in the anions. The wet deposition of sulfur (S) and nitrogen (N) was 70.9 ± 67 mg·(m2·month)−1 and 244.8 ± 270.9 mg·(m2·month)−1, respectively. The meteoric water line in Xi'an was δD = 7.29δ18O+3.72 (R2 = 0.99). δD, δ18O, and d-excess analysis indicated the influence of evaporation on the dissolved solutes in rainwater, especially in the dry season. Rainwater acidity in the Xi'an city was mainly neutralized by Ca2+ and NH4+, and the neutralization ability in Xi'an city is higher than the southern China cities. Correlation analysis (CA), positive matrix factorization (PMF), and the backward air masses trajectory model identified high NH4+ and Ca2+ in rainwater were mainly originated from local agricultural activities and loess dust, while NO3− and SO42− were associated with local coal combustion and vehicle exhaust sources. High inputs of dusts and coal combustion in spring and winter resulted in elevated values of pH and major ions in Xi'an. Due to the air pollution control policy, air quality in Xi'an is getting better in recent years. Our study highlights the influence of anthropogenic activities and loess dusts on the rainwater hydrochemistry in Xi'an and provides important dataset for air pollution control for other cities in semi-arid and arid regions.

The impacts of clean energy policies on air pollutants and CO2 emission reduction in Shaanxi, China

In response to environmental problems, China has implemented many policies to control its emission of air pollutants and CO2. As a significant source of pollutant emissions, energy use has received special attention. Shaanxi Province is a region of China with major thermal power generation, which consumes a large amount of fossil fuel and causes severe deterioration in ambient air quality. However, it is rich in natural resources that could support the development of solar energy, wind energy, and other renewable clean energies, making it a typical example of a region suitable for energy structure transformation. On the basis of environmental statistical data, field surveys, and data from the Shaanxi Provincial Bureau of Statistics, this study developed an inventory of anthropogenic source emissions of seven pollutants in 2017 in Shaanxi Province. In accordance with the established inventory, various scenarios were considered to analyze the impact of energy structure transformation on air pollutant emissions. In comparison with the Business-as-Usual scenario, the comprehensive clean energy use scenario reduced SO2, NOx, CO, PM10, PM2.5, VOCs, NH3 and CO2 emissions by 32.50%, 33.10%, 14.56%, 26.64%, 16.72%, 2.88%, 4.36% and 36.85%, respectively. Ambitious development of clean energy, such as wind and solar, could greatly reduce the emission of air pollutants, especially CO2, SO2 and NOx, that are derived mainly from fossil fuel combustion, showing that strict control of the energy structure could reduce pollutant emissions. This work is important for quantifying the impact of energy restructuring on regional air quality and providing pollution control policies for environmental managers.