Air Pollution Prevention And Control Action Plan Research Articles

Fine particulate matter and ozone variability with regional and local meteorology in Beijing, China

Fine particulate matter (PM2.5) and surface ozone air pollution have severe health consequences. Since China implemented the nationwide Air Pollution Prevention and Control Action Plan (APPCAP) in 2013, annual average PM2.5 concentrations have decreased while O3 concentration have increased in Beijing. It is unclear, however, to the extent that short-term meteorological variability has influenced these trends. To separate the influence of meteorology from long-term emissions-induced changes, we quantify the portion of the long-term PM2.5 and O3 concentration signals associated with short-term meteorological variability. Building off recent literature highlighting the regional nature of pollutant variability, we incorporate both locally observed meteorology and average regional reanalysis. We isolated sub-seasonal variability using the Kolmogorov-Zurbenko filter. Next, we trained and compared the utility of three statistical models of varying complexity (a linear model, a general additive model with splines, and a random forest) in their ability to predict out-of-sample daily concentrations. The random forest model yields the best predictive capability in holdout tests and predicts changing meteorological contributions to PM2.5 and ozone concurrent with changing concentrations across the study period. Results show an overall decrease in meteorology induced PM2.5 concentration variability at daily scales since 2013, but variability from meteorology has increased relative to mean PM2.5 concentrations. In contrast, O3 shows the opposite trend, with increasing meteorology-induced variability (meteorology-induced variability normalized by mean observed O3 has decreased). Our results show the importance of including regional meteorology in explaining local PM2.5 and O3 variability and quantify links between long-term policy implementation and short-term meteorological contributions to pollutant concentrations.

Reduction in polycyclic aromatic hydrocarbon exposure in Beijing following China’s clean air actions

Exposure to polycyclic aromatic hydrocarbons (PAHs) in the Chinese population was among the highest globally and associated with various adverse effects. This study examines the impact of China’s two-phase clean air initiatives, namely the Air Pollution Prevention and Control Action Plan (APPCAP) in 2013–2017 and the Blue-Sky Defense War (BSDW) in 2018–2020, on PAH levels and human exposures in Beijing. To evaluate the effects of APPCAP, we measured 16 PAHs in 287 PM2.5 samples collected in Beijing and 9 PAH metabolites in 358 urine samples obtained from 54 individuals who traveled from Los Angeles to Beijing between 2014 and 2018. The concentration of PM2.5-bound benzo[a]pyrene equivalents (BaPeq) decreased by 88.5% in 2014–2018 due to reduced traffic, coal, and biomass emissions. PAH metabolite concentrations in travelers’ urine decreased by 52.3% in Beijing, correlated with changes in PM2.5 and NO2 levels. In contrast, no significant changes were observed in Los Angeles. To evaluate BSDW’s effects, we collected 123 additional PM2.5 samples for PAH measurements in 2019–2021. We observed sustained reductions in BaPeq concentrations attributable to reductions in coal and biomass emissions during the BSDW phase, but those from traffic sources remained unchanged. After accounting for meteorological factors, China’s two-phase clean air initiatives jointly reduced Beijing’s PM2.5-bound BaPeq concentrations by 96.6% from 2014 to 2021. These findings provide compelling evidence for the effectiveness of China’s clean air actions in mitigating population exposure to PAHs in Beijing.

Effects of " Air Pollution Prevention and Control Action Plan " on PM2.5 and Chemical Compositions in Zhengzhou in Polluted Winters

The Air Pollution Prevention and Control Action Plan （APPCAP） was promulgated in China in 2013. To explore the effectiveness of APPCAP on PM2.5 in winter in Zhengzhou, PM2.5 samples were collected in Zhengzhou Monitoring Center during December 2013 and December 2018. The chemical composition of PM2.5 was analyzed, including EC, OC, water soluble ions, and metal elements. Pollution episodes under different stages were selected to investigate the changes in PM2.5 concentration and composition. The results showed that： ① The average concentration of PM2.5 in winter in Zhengzhou decreased from （215.38 ±107.28） μg·m-3 in 2013 to （77.45 ±49.81） μg·m-3 in 2018, with a decrease rate of 64%. ② The concentrations of EC, K+, SO42-, and Cl- decreased by 85%, 80%, 78%, and 72%, respectively, and the decrease rate in OC, NH4+, and NO3- was 50%, 41%, and 32%, respectively. ③ Compared with those in winter of 2013, the ratios of OC/EC in winter of 2018 increased by 2.6 times, and the proportion of secondary organic carbon in OC increased to 57%； meanwhile, values of sulfur oxidation rate and nitrogen oxidation rate increased by 1.5 and 1.0 times, respectively, indicating heavy secondary pollution in Zhengzhou. ④ The mass ratios of NO3-/SO42-increased from 0.8 ±0.2 in 2013 to 2.5 ±1.0 in 2018, indicating that the contribution of mobile sources increased and surpassed fixed sources as the main source in Zhengzhou. ⑤The comparison results of different stages of the heavy pollution process showed that ρ（PM2.5） decreased significantly in 2018 compared with that in 2013, with the peak concentration decreasing by 61%. The main chemical composition changed from OC, NO3-, SO42-, and NH4+ to OC, NO3-, and NH4+. The results indicated that the primary emission source control in Zhengzhou had achieved remarkable effects, but the contribution of secondary generation to PM2.5 showed an elevated trend； thus, the influence of secondary generation requires further attention in the future.

Environmental regulation and labor demand: Evidence from China's air pollution prevention and Control Action Plan

In response to environmental regulatory pressure from the government, enterprises – as the main employers of labor – adjust their production-related choices and may alter their demand for labor. Numerous researches have probed into how environmental regulations affect the labor demand, which has emerged as a significant concern in the discourse around the adoption of environmental regulation policies. Nonetheless, many researches predominantly concentrates on the evaluation on the effects of environmental regulations on economic and environmental levels. Moreover, rare attention has been paid to how environmental regulations affect social activities, especially in terms of labor demands. As a result, the Air Pollution Prevention and Control Action Plan (APPCAP) is adopted as a “quasi-natural experiment” and a difference-in-differences model is employed to analyze the effects of the APPCAP on labor demands of companies. Hence, the 2008–2020 panel data are considered for the 3,949 Chinese A-share listed enterprises. Furthermore, this paper probes deeply into the underlying mechanisms based on mediation models. The following findings are thus concluded: (1) The labor demands of enterprises can be remarkably increased by APPCAP; and the result is still persuasive even though the endogeneity issues are taken into account. (2) APPCAP improves enterprise labor demand through the output and factor substitution effects. (3) As evidently revealed by heterogeneity analysis, the APPCAP could significant positive affect the labor demand size in state-owned companies, large-scale companies, new companies, and companies in polluting industries. (4) The APPCAP strikingly boosts the demand for labor force with high skills. Nevertheless, it exerts little influence on the demand for labor force with low skills and company salary levels. Therefore, the government must continue to steadfastly implement environmental regulatory policies but adopt different policies based on enterprise characteristics. Overall, this study provides micro-level experimental evidence for more in-depth understanding of how environmental policies affect labor market, which is particularly important for actively resolving social employment problems and exploring new growth points in enterprise employment.

How does the impact of a two-stage air pollution control policy on air quality different? Evidence from 258 cities in China

Air pollution control has become a core task in the construction of China's “ecological civilization”. From 2013 to 2020, the Chinese government successively implemented two consecutive environmental management policies targeting air pollution, namely the Air Pollution Prevention and Control Action Plan (APPCAP) and the Blue Sky Defense War (BSDW). To compare and analyze the effects of these two consecutive policies on air pollution control and their differences in governance mechanisms, this paper employs daily air pollution data from 258 cities in China from January 2013 to September 2020 for empirical analysis. We examines the direct impact of the two-stage policies on air pollution and explores the impact mechanisms from three aspects: technological effects, structural effects, and scale effects. The results indicate: (1) Both APPCAP and BSDW significantly reduced AQI, PM2.5, PM10, SO2, nitrogen dioxide, and CO. (2) Compared to APPCAP, BSDW had a stronger effect on reducing nitrogen dioxide and managed O3 in coordination. (3) APPCAP did not have significant impacts on technology, scale, and structure effects, whereas BSDW significantly promoted technological innovation and industrial restructuring but significantly suppressed the scale effect. Our work provides new empirical evidence for the policy heterogeneity in air pollution control and offers useful policy implications for improving air quality and coordinated pollution control.

Direct radiative forcing of light-absorbing carbonaceous aerosols in China

China is an important emitter of light-absorbing carbonaceous aerosols (LACs), including black carbon (BC) and brown carbon (BrC). Currently, there are large uncertainties in model-estimated direct radiative forcing (DRF) of LACs, partially due to the poor understanding of the emissions and optical properties of LACs. In this study, we estimated the DRF of LACs over China during the implementation of the Air Pollution Prevention and Control Action Plan (APPCAP) using the global chemical transport model (GEOS-Chem) coupled with the Rapid Radiative Transfer Model of GCMs (RRTMG). We updated the refractive index of BC, includedbiomass burning (BB) sources, biofuel (BF) and coal combustion (CC) sources in the residential sector as BrC emission sources and the optical properties were updated, which were not fully considered in the previous model studies. Our results showed that model could reasonably capture the spatial and temporal variations of LACs in China with the correlation coefficients between model simulated and Aerosol Robotic Network (AERONET) observed daily absorption aerosol optical depth (AAOD) of LACs at 440 nm above 0.63 and the corresponding values of the normalized mean bias within ±30%. The simulated annual mean LACs AAOD at 440 nm in China was 0.016 (0.021) in 2017 (2014) and BrC contributed about 20% (21%). The estimated annual mean clear-sky LACs DRF at the top of the atmosphere in China was 1.02 W m−2 in 2017 and 1.38 W m−2 in 2014, and the contribution of BrC was about 10% and 11%, respectively, which was dominated by the BF sources (46% in 2017 and 44% in 2014) and the BB sources (38% in 2017 and 43% in 2014), with CC sources being low (16% in 2017 and 13% in 2014). The annual mean AAOD and DRF of LACs in China decreased by 0.005 and 0.36 W m−2 from 2014 to 2017, which were largely attributed to the reductions of anthropogenic emissions during the implementation of APPCAP. Our results would improve the understanding of the light absorption capacity and climate effects of LACs in China.

Does environmental regulation pressure induce the green innovation of enterprises? Quasi-natural experiment of China's air pollution prevention and control action plan

ABSTRACT Air Pollution Prevention and Control Action Plan (APPCAP) is one of the most influential command-and-control environmental regulations (CMC) in China. Whether it can promote the green innovation performance of enterprises remains unclear. Based on the ‘Green Patent List’ issued by the World Intellectual Property Organization (WIPO) and the Chinese listed companies’ data, this paper applies the quasi-natural experiment methods of the difference-in-differences model and difference-in-difference-in-differences model to identify the impact of environmental regulation pressure on the green innovation of enterprises. The study finds that implementing the APPCAP promotes the enterprises’ green innovation performance in quantity and quality. Heterogeneity analysis shows that the green innovation effect of APPCAP is more obvious for those samples in the eastern region, with features of capital-intensive, labour-intensive, and low market concentration. Furthermore, our findings further support the weak version of the Porter hypothesis (PH), Whose path is that the implementation of APPCAP induces enterprises’ green innovation by promoting their innovation investment. These findings provide policy implications for the coordination of environmental regulation and green transformation in pursuit of the goal of carbon peaking and carbon neutrality goals.

Restructuring and relocation of polluting industries under air pollution control: Evidence from industrial investment flows between Chinese cities

This paper analyzes the impact of the Air Pollution Prevention and Control Action Plan (APPCAP), an environmental policy for particulate matter reduction implemented in 2013, on the restructuring and relocation of Chinese polluting industries. Based on the paid-in capital of newly registered enterprises, we construct the investment flows at the city-industry level to effectively identify the adjustment of polluting industrial structure and the phenomenon of pollution transfer. We estimate the three-dimensional variations in the investment flows, i.e., time (pre-treatment versus post-treatment), region (more stringent regulations versus more lenient ones), and industry (heavily polluting industries versus lightly polluting ones) with the aid of a difference-in-difference-in-differences (DDD) estimation technique. Our empirical results help to understand the comprehensive impact of command-and-control environmental policy in two ways. For one thing, we find the positive effects of APPCAP in curbing the expansion of polluting industries that would emit smoke and dust in production; for another, our results reveal the latent pollution transfer brought by the differentiated regulation intensity of APPCAP implemented in different regions.

Spatiotemporal dynamics, traceability analysis, and exposure risks of antibiotic resistance genes in PM2.5 in Handan, China.

Fine particulate matter (PM2.5) seriously affects environmental air quality and human health, and antibiotic resistance genes (ARGs) in PM2.5 posed a great challenge to clinical medicine. The year of 2013-2017 was an important 5-year period for the implementation of Air Pollution Prevention and Control Action Plan (APPCAP) in China. Here, we took Handan, a PM2.5 polluted city in northern China, as the research object and analyzed ARGs in PM2.5 in winter (January) from 2013 to 2017. The results showed that the abundance of ARGs was the highest in 2013 (3.7 × 10-2 copies/16S rRNA), and ARGs were positively correlated with air quality index (AQI) (r = 0.328, P < 0.05) and PM2.5 concentration (r = 0.377, P = 0.020 < 0.05) in the 5-year period. The ARGs carried by PM2.5 in four functional regions of sewage treatment plant, steel works, university, and park showed that sul1 and qepA had higher abundance in each functional region, and the total ARG abundance in sewage treatment plant (1.3 × 10-1 copies/16S rRNA) was the highest, while lowest in park (2.0 × 10-3 copies/16S rRNA). Potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) model were used to trace the pollutants at the sampling points, which indicated that the surrounding cities contributed more than quarter to the sampling points. Therefore, regional transportation reduces the spatial distribution difference of ARGs in PM2.5. The exposure dose of ARGs in different functional regions illustrated that the total inhaled dose of ARGs in sewage treatment plant (1.7 × 105 copies/d) was the highest, while lowest in park (3.2 × 104 copies/d). This study is of great significance for assessing the distribution and sources of ARGs under the clean air initiative in China.

Air pollution prevention in central China: Effects on particulate-bound PAHs from 2010 to 2018

Long-term trends in particulate-bound polycyclic aromatic hydrocarbon (PAH) concentrations in air in Zhengzhou (a severely polluted city in central China) between 2010 and 2018 were studied to assess the effectiveness of an air pollution prevention and control action plan (APPCAP) implemented in 2013. The PM2.5, sum of 16 PAHs (Σ16 PAHs), benzo[a]pyrene (BaP), and BaP toxic equivalent concentrations were high before 2013 but 41%, 77%, 77%, and 78% lower, respectively, after the APPCAP. The maximum daily Σ16 PAHs concentration between 2014 and 2018 was 338 ng/m3, 65% lower than the maximum of 961 ng/m3 between 2010 and 2013. The ratio between the Σ16 PAHs concentrations in winter and summer decreased over time and was 8.0 in 2011 and 1.5 in 2017. The most abundant PAH was benzo[b]fluoranthene, for which the 9-year mean concentration was 14 ± 21 ng/m3 (15% of the Σ16 PAHs concentration). The mean benzo[b]fluoranthene concentration decreased from 28 ± 27 ng/m3 before to 5 ± 4 ng/m3 after the APPCAP (an 83% decrease). The mean daily BaP concentrations were 0.1–62.8 ng/m3, and >56% exceeded the daily standard limit of 2.5 ng/m3 for air. The BaP concentration decreased from 10 ± 8 ng/m3 before to 2 ± 2 ng/m3 after the APPCAP (a 77% decrease). Diagnostic ratios and positive matrix factorization model results indicated that coal combustion and vehicle exhausts were important sources of PAHs throughout the study period, contributing >70% of the Σ16 PAHs concentrations. The APPCAP increased the relative contribution of vehicle exhausts from 29% to 35% but decreased the Σ16 PAHs concentration attributed to vehicle exhausts from 48 to 12 ng/m3. The PAH concentration attributed to vehicle exhausts decreased by 79% even though vehicle numbers strongly increased, indicating that pollution caused by vehicles was controlled well. The relative contribution of coal combustion remained stable but the PAH concentration attributed to coal combustion decreased from 68 ng/m3 before to 13 ng/m3 after the APPCAP. Vehicles made dominant contributions to the incremental lifetime cancer risk (ILCRs) before and after the APPCAP even though the APPCAP decreased the ILCRs by 78%. Coal combustion was the dominant source of PAHs but contributed only 12–15% of the ILCRs. The APPCAP decreased PAH emissions and changed the contributions of different sources of PAHs, and thus strongly affected the overall toxicity of PAHs to humans.

Revealing the impact of China's clean air policies on synergetic control of CO2 and air pollutant emissions: Evidence from Chinese cities

China is presently confronted with the intricate challenge of simultaneously mitigating air pollution and decelerating the pace of climate change. An integrated perspective to investigate the synergetic control of CO2 and air pollutant emissions is in an urgent need. Using data for 284 Chinese cities from 2009 to 2017, we introduced an indicator called coupling and coordination degree of CO2 and air pollutant emissions control (CCD) and found an upward and spatial agglomeration trend of CCD distribution during the research period. Then, this study posed a specific focus on the impact of China's Air Pollution Prevention and Control Action Plan (APPCAP). The DID model revealed that implementation of the APPCAP resulted in a 4.0% increase in CCD for cities with special emission limits, attributed to industrial structural adjustments and the promotion of technology innovation. Furthermore, we also identified positive spillover effects of the APPCAP on neighboring control group cities situated within 350 km of the treatment group cities, providing an explanation for the spatial agglomeration trend observed in CCD distribution. These findings hold significant implications for the synergetic control in China and underscored the potential benefits of industrial structural adjustments and technology innovation in mitigating environmental pollution.

Assessment of Regional Differences in the Implementation of the Air Pollution Prevention and Control Action Plan in China.

Air pollution is still an important risk factor that endangers the health of Chinese people, leading the government to implement a series of policies to address air pollution. This study takes the Air Pollution Prevention and Control Action Plan (APPCAP) proposed in 2013 as the object and uses the combined data set of China's 2000-2019 economic panel data and PM2.5 remote sensing data to analyse the implementation effect of the policy by the multiperiod difference-in-differences method, considering regional heterogeneity. The results show that the implementation of the APPCAP significantly reduced the PM2.5 concentration in China, and the effect was stronger in the Yangtze River Delta region. Future governance policies should further consider local characteristics and determine pollution control goals and measures according to local conditions.

Stringent environmental regulation and inconsistent green innovation behavior: Evidence from air pollution prevention and control action plan in China

Air Pollution Prevention and Control Action Plan (APPCAP), which was introduced in 2013, had been hailed as the most stringent policy for air pollution control in China. In this paper, we evaluate the impact of APPCAP on the green innovation behavior of listed companies by adopting the difference-in-difference (DID) identification technique. And three innovation indicators (quantity, quality, and diversity) are constructed based on the green invention patent data in China during 2008–2017. We find that stricter emission reduction targets will induce listed companies to increase the applications for green inventions. Mechanism analysis further proves that financial resources are essential to promote green innovation under the pressure of air pollution control. And broadening financing channels as well as the support of government subsidies accompanied by the implementation of APPCAP would raise the enthusiasm of listed companies to invent. Specifically, state-owned companies and non-innovators, which are both sensitive to the government's decisions, are proven to be responsible for the rapid growth of green invention applications. Furthermore, we find that the companies' green innovation behavior is inconsistent. APPCAP will enhance the green innovation diversity, but does not improve the quality.

Evolution of PM2.5 Chemical Composition and Sources in Nanjing During the Implementation of the APPCAP

To acquire a deeper understanding about the impact of the Air Pollution Prevention and Control Action Plan (APPCAP) on ambient fine particulate matter (PM2.5), measurements of PM2.5 chemical components were conducted in the urban area of Nanjing during the implementation of the APPCAP. Evolution characteristics of several properties of the PM2.5 were studied, including the concentrations, proportions, and enrichment factors of major PM2.5 components and the acidity of the PM2.5. In addition, the source apportion of the PM2.5 was analyzed using the positive matrix factorization (PMF) model. The results showed that during the implementation of the APPCAP, the proportion of sulfate (SO42-) in PM2.5 decreased, whereas the proportions of nitrate (NO-3) and ammonium (NH+4) increased significantly together, from 25.58% in 2014 to 37.15% in 2017. The concentrations of carbon components (OC and EC) decreased in the early stage of the APPCAP; however, the decreasing trend slowed down in the later stage. In particular, the proportion of organic carbon (OC) increased, especially for the secondary organic carbon (SOC). The acidity of the PM2.5 decreased significantly, with the molar equivalent ratio of cations and anions increasing from 0.83 in 2014 to 1.13 in 2017. The contributions of coal combustion and the metallurgical and petrochemical industry to the PM2.5 generally showed a downward trend, whereas the contribution of vehicle emissions increased rapidly, from 8.78% in 2014 to 13.92% in 2017. The contribution of general fugitive dust fluctuated greatly, but that of soil fugitive dust showed an upward trend. This study suggested that the direct PM2.5 emissions, such as those from coal combustion and industries, were effectively controlled during the implementation of the APPCAP; however, the contribution of secondary aerosols became increasingly prominent, which indicates that future policies of PM2.5 pollution control should focus on emission reduction of the precursors such as NOx, NH3, and VOCs. In addition, the effects of increasing alkalization of the PM2.5 and enhanced oxidizability of the atmosphere on the PM2.5 pollution also require further attention.

Population Aging Driven Slowdown in the Reduction of Economic Cost-Attributed to PM2.5 Pollution after 2013 in China.

Since seniors are more susceptible to ambient fine particulate matter (PM2.5), the high economic cost to protect the aged population from PM2.5 exposure is expected. Significant efforts have been made in China to mitigate PM2.5 since 2013 under the Air Pollution Prevention and Control Action (APPCA) Plan, which remarkably reduced PM2.5 contamination and its associated economic and health burdens. However, to what extent population aging could influence the economic benefits from the APPCA Plan is unclear. Here, we estimate five driving factors contributing to the economic cost of mortality attributable to PM2.5 pollution. The results show that the economic cost attributed to PM2.5 pollution increased from 1980 to 2013 and decreased from 2013 to 2019 in China, benefiting from the APPCA Plan. Since 2013, population aging becomes the most significant positive driver that almost offsets declining economic cost from significantly declining PM2.5. Rapid aging has become an enormous burden to PM2.5-associated health and economic loss. Our findings suggest that we should further improve air quality and enhance health care for the elderly population.

Air pollution prevention and control action plan substantially reduced PM2.5 concentration in China

As part of China's committed efforts to alleviate and control air pollution in key regions, the Air Pollution Prevention and Control Action Plan (APPCAP) was implemented in 2013 and a series of regulatory measures, including a mandatory and strengthened enterprise air pollutant emission standard was rolled out. However, the present literature has focused limited attention to the actual effects of APPCAP on PM2.5 pollution treatment. Using panel data from 271 prefecture-level cities covering 2008 and 2018, this paper used the difference-in-differences (DID) and propensity score matching difference-in-differences (PSM DID) to explore for the first time the policy effect on air quality. The superposition effect caused by the establishment of a carbon emission trading scheme is empirically considered by using the difference-in-difference-in- differences (DDD) strategy. Several important findings are derived: 1) The APPCAP exerts significant negative effects on fine particulate matter (PM2.5) concentration and SO2 emissions in the pilot areas. 2) Results of the DDD model show that China's APPCAP still exert significant negative effects on PM2.5 concentration and SO2 emissions in the pilot areas of the carbon emission trading scheme. 3) The heterogeneity analysis results indicate that the effects of China's APPCAP on air pollution in the key urban agglomerations are consistent and significantly negative under different conditions.

Decadal changes in PM2.5-related health impacts in China from 1990 to 2019 and implications for current and future emission controls

In China, the rapid development of the economy and implementation of multiple emission control policies in recent decades have been accompanied by dramatic changes in air quality. In this study, PM2.5 concentrations estimated by using MERRA-2 reanalysis data were integrated into the Global Exposure Mortality Model (GEMM) to explore the spatiotemporal variation of nationwide PM2.5-related premature mortality from 1990 to 2019, and the driving factors behind decadal changes were evaluated. Since 2000, as a result of PM2.5 pollution, air quality in China has deteriorated substantially, especially in the fast-developing eastern and southern parts. In 2009, the nationwide population-weighted (PW) PM2.5 concentration peaked at 41.4 μg/m3 (95% confidence interval [CI], 36.7–46.2). Simultaneously, the GEMM results revealed that nationwide PM2.5-related deaths increased remarkably from 1089 (95% CI, 965–1210) thousand in 1990 to 1795 (1597–1986) thousand in 2009. The implementation of the toughest-ever Air Pollution Prevention and Control Action Plan (APPCAP) in 2013 effectively controlled PM2.5 pollution in China. By 2018, the nationwide PW PM2.5 concentration had decreased to 34.0 (29.2–38.9) μg/m3. Dynamic trend prediction revealed that, although the APPCAP achieved substantial health benefits, the policy did not result in further remarkable reductions in PM2.5-related deaths; in 2019, deaths peaked at 1932 (1716–2140) thousand. PM2.5-related deaths in 2030 were projected for each of four emission control scenarios. The results of the driving factor analysis and the future projections indicated that the health benefits from improving air quality are likely to be counterbalanced by changes in the population age structure. Because population ageing is becoming more and more rapid in China and the challenge of climate change is increasing, the results of this study imply that policymakers need to implement more stringent measures and set more ambitious emission control targets to reduce nationwide PM2.5-related premature mortality in the future.

Characteristics of Water-soluble Ions in an Autumn Haze Process in the Southern Sichuan Urban Agglomeration After the Implementation of China's Air Pollution Prevention and Control Action Plan

To investigate the PM2.5 pollution in the southern Sichuan urban agglomeration after the implementation of China's Air Pollution Prevention and Control Action Plan (APPCAP), PM2.5 samples were simultaneously collected in four cities (Neijiang, Zigong, Yibin, and Luzhou) from November 7 to 19, 2018. The pollution characteristics of PM2.5 and main water-soluble ions were analyzed in combination with the synoptic situation, and the influence of regional transport on atmospheric pollution was also discussed in this study. The results showed that the mean ρ(PM2.5) in this region was (67.2±38.3) μg·m-3, being highest in Luzhou and lowest in Neijiang. The proportion of SNA (SO42-, NO3-, and NH4+) in PM2.5 was 33.3%, among which NO3- was dominant. From the intermediate stage (2015) to the end(2018) of the implementation of APPCAP, ρ(PM2.5) values were increased by 13.8%, 47.2%, and 69.1% in Neijiang, Yibin, and Luzhou, respectively, though unchanged in Zigong. Due to the significant reduction in ρ(SO2) but slight decrease or increase in ρ(NO2), as well as the lack of controlling NH3 emissions, from 2015 to 2018, ρ(NO3-) had increased by 36.7%-116.0%, whereas ρ(SO42-) decreased by 19.8%-40.2%, and ρ(NH4+) changed slightly in four cities. On haze days, the nitrogen oxidation rate (NOR) increased by 60.0%-118.2%, whereas the sulfur oxidation rate (SOR) increased slightly or decreased, leading to a significant increase in ρ(NO3-) (2.7-3.0 times that on clean days) and NO3-/SO42- mass ratios (1.7-1.9 on haze days). These values indicated that the secondary formation of nitrate was the dominant chemical mechanism in this haze process. On haze days, the PM2.5 pollution in this region was mainly affected by the regional transport within Sichuan Basin, particularly by the northeasterly air masses passing through Chongqing.

Quantifying ecological and health risks of ground-level O3 across China during the implementation of the “Three-year Action Plan for Cleaner Air”

After China implemented the Air Pollution Prevention and Control Action Plan (APPCAP), PM2.5 concentrations decreased but were still higher than national standards in major areas and ozone (O3) concentration increased unintentionally. To further decrease PM2.5 concentrations and reduce days with severe air pollution, the government promulgated the “Three-year (2018–2020) Action Plan for Cleaner Air” (the Three-year Action Plan) in 2018. During the three-year Action Plan, a few studies reported a continuous decline in PM2.5, but it is unclear whether O3 and its effects also increase with the decrease of PM2.5 like during APPCAP. In this study, for the first time, we systematically assessed changes in ground-level O3 concentrations and related ecological and health risks during the period of the Three-year Action Plan using nationwide O3 measurements. The national MDA8, Exceedance, and SOMO35 indicators were reduced by 3.8%, 28.5%, and 12.6%, respectively, ecological risk indicators of M12, M7, SUM06, AOT40, and W126 were reduced by 5.4%, 5.6%, 19.5%, 15.4%, and 18.6%, respectively, from 2018 to 2020. Spatially, the greatest reduction in all the indicators except MDA8 occurred in Pearl River Delta, followed by Fen Wei Plains, while Beijing-Tianjin-Hebei, Chengdu-Chongqing, and Yangtze River Delta presented relatively small reductions. Between 2018 and 2020, the production losses caused by O3 for wheat and rice decreased by 21.4% and 17.6%, respectively. Long-term exposure to O3 across China over 2020 was estimated to cause about 160,795 (95% CI: 81,515–312,983) for all-cause mortality, 107,128 (95% CI: 36,703–173,823) for cardiovascular mortality, and 34,444 (95% CI: 0–72,609) for respiratory mortality, indicating decreases of 9.93%, 9.86%, and 9.78%, respectively, compared to the year 2018. Taken together, our results provided the first direct evidence for China's efforts to control O3 pollution in recent years.

Assessment of Emission Reduction and Meteorological Change in PM2.5 and Transport Flux in Typical Cities Cluster during 2013–2017

Under the Air Pollution Prevention and Control Action Plan (APPCAP) implemented, China has witnessed an air quality change during the past five years, yet the main influence factors remain relatively unexplored. Taking the Beijing-Tianjin-Hebei (BTH) and Yangtze River Delta (YRD) regions as typical cluster cities, the Weather Research Forecasting (WRF) and Comprehensive Air Quality Model with Extension (CAMx) were introduced to demonstrate the meteorological and emission contribution and PM2.5 flux distribution. The results showed that the PM2.5 concentration in BTH and YRD significantly declined with a descend ratio of −39.6% and −28.1%, respectively. For the meteorological contribution, those regions had a similar tendency with unfavorable conditions in 2013–2015 (contribution concentration 1.6–3.8 μg/m3 and 1.1–3.6 μg/m3) and favorable in 2016 (contribution concentration −1.5 μg/m3 and −0.2 μg/m3). Further, the absolute value of the net flux’s intensity was positively correlated with the degree of the favorable/unfavorable weather conditions. When it came to emission intensity, the total net inflow flux increased, and the outflow flux decreased significantly across the border with the emission increasing. In short: the aforementioned results confirmed the effectiveness of the regional joint emission control and provided scientific support for the proposed effective joint control measures.