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To quantitatively assess the health benefits brought by the implementation of the Action Plan of Air Pollution Prevention and Control, we firstly analyzed the spatial and temporal changes of PM 2.5 population-weighted concentrations over China from 2013 to 2017. The BenMAP model was used to analyze the differences in premature death between the PM 2.5 baseline scenario in 2013 and the control scenario in 2017 in 338 prefecture-level cities nationwide, so as to quantitatively analyze the number of premature deaths in 31 provinces. The results show that compared with other provinces, the largest reduction in premature deaths due to the significant decrease of PM 2.5 concentration occurred in the Beijing-Tianjin-Hebei region and its surrounding regions, and the environmental health benefits from air quality have been greatly improved. The results show that from 2013 to 2017 the population weighted PM 2.5 concentration was decreasing year by year due to the significant decrease in PM 2.5 concentration; Beijing, Tianjin, Hebei, and the surrounding areas witnessed the largest reduction in premature deaths. In 2017, the number of avoided premature deaths in 280 prefecture-level cities nationwide increased, but declined in 58 cities. Taking the target value of the first phase of the WHO transition period (an annual average PM 2.5 concentration of 35 μg·m -3 ) as the control scenario, it is estimated that the number of premature deaths in 2013 was approximately 101293, and in 2017 was approximately 41080. The implementation of the Action Plan helped to avoid approximately 60213 premature deaths. According to the method of 'willingness to pay', the monetary benefits are estimated to be approximately 54.97 billion yuan.

Nitrate (NO 3 - ) is a key component of secondary inorganic aerosols and PM 2.5 . However, the contributions of nitrogen oxides (NO x ) emission sources to NO 3 - in PM 2.5 remain poorly constrained. This study measured nitrogen (N) isotopes of NO 3 - (hereafter as δ 15 N-NO 3 - ) in PM 2.5 collected at Beijing in 2014. We observed that δ 15 N-NO 3 - values in PM 2.5 (-2.3‰ - 19.7‰; 7.3 ± 5.4‰ annually) were significantly higher in winter (11.9 ± 4.4‰) than in summer (2.2 ± 2.5‰). The δ 15 N differences between source NO x and NO 3 - in PM 2.5 (hereafter as Δ values) were estimated by a computation module as 7.8 ± 2.2‰ - 10.4 ± 1.6‰ (8.8 ± 2.4‰). Using the Δ values and δ 15 N values of NO x from major fossil (coal combustion, vehicle exhausts) and non-fossil sources (biomass burning, microbial N cycle), contributions of major NO x sources to NO 3 - in PM 2.5 were further estimated by the SIAR model. We found that seasonal variations of δ 15 N-NO 3 - values in PM 2.5 of Beijing were mainly caused by those of NO x contributions from coal combustion (38 ± 10% in winter, 20 ± 9% in summer). Annually, NO x from coal combustion, vehicle exhausts, biomass burning, and microbial N cycle contributed 28 ± 12%, 29 ± 17%, 27 ± 15%, and 16 ± 7% to NO 3 - in PM 2.5 , respectively, showing actually comparable contributions between non-fossil NO x (43 ± 16%) and fossil NO x (57 ± 21%). These results are useful for planning the reduction of NO x emissions in city environments and for elucidating relationships between regional NO x emissions and atmospheric NO 3 - pollution or deposition., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Leaves of Platanus orientalis were collected since Mar. 2009 till Apr. 2010, in an urban area at Guiyang. After mass of experiments and analysis, we carried out constructing the temporal variation of foliar N% and delta15 N: both higher in Spring/Summer, lower in Autumn, no data of Winter because of leaf abscission. Results showed that foliar N% varied from 1.48% to 5.27%, with an annual average of 3.36%, while the average concentration of total N in rhizospheric soil was 0.29%. The foliar N% rose and fell relative to DIN in rainwater (range from 0.57 mg x L(-1) to 6.74 mg x L(-1)), indicating that the N% content in foliar tissue of plant was approximately proportional to atmospheric N inputs. The range of foliar delta15N were from 4.48 per thousand to 8.39 per thousand, with the average of 6.33 per thousand, much higher than the delta15N-NH4+ of rain water (-19.76 per thousand(-) -10.41 per thousand) and delta15TN of rhizospheric soil (3.19 per thousand +/- 1.04 per thousand). Besides, a good uniform correlation between foliar delta15N and delta15N-NH4+ of rain water were found. As synthesis of two main N sources, the more positive delta15N values of Platanus orientalis can be explained by isotopic fractionation during N uptake and basipetal translocation. These responses of both foliar N% and delta15N to atmospheric nitrogen deposition, revealed the potential value in using vascular leaves as bio-monitors for assessment of N deposition, furthermore, for prevention and control of air pollution in urban ecosystem.

Foliar δ(34)S values of three soil-growing plant species (Platanus Orientalis L., Osmanthus fragrans L. and Cinnamomum camphora) have been analyzed to indicate atmospheric sulfur. The foliar δ(34)S values of the three plant species averaged -3.11±1.94‰, similar to those of both soil sulfur (-3.73±1.04‰) and rainwater sulfate (-3.07±2.74‰). This may indicate that little isotopic fractionation had taken place in the process of sulfur uptake by root or leaves. The δ(34)S values changed little in the transition from mature leaves to old/senescing leaves for both the plane tree and the osmanthus tree, suggestive of little isotope effect during sulfur redistribution in plant tissues. Significantly linear correlation between δ(34)S values of leaves and rainwater sulfate for the plane and osmanthus trees allowed the tracing of temporal variations of atmospheric sulfur by means of foliar sulfur isotope, while foliage δ(34)S values of the camphor is not an effective indicator of atmospheric sulfur., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

In China, coal combustion is the most important source of atmospheric sulfur pollution. Moss sulfur isotopic signatures have been believed to hold source-specific information that can serve as a fingerprint to identify atmospheric sulfur sources. In cities where only local coals were combusted, we observed a good correspondence of average sulfur isotope ratios in urban mosses (Haplocladium microphyllum) to the values of local coals (δ(coals) = 1.455δ(mosses)- 3.945, R(2) = 0.975, p = 0.01). But if different types of coals were combusted, we did not know whether moss sulfur isotope ratios can indicate mixed coals. To confirm this, using a mixing model we estimated the ratios of imported coal to local coals at cities where both coals were used. We found that the estimated ratios at large cities (>1 million people) where both coals were used were similar to the reported ratios in their respective provinces. For small cities (<0.5 million people) in Jiangxi Province and other provinces, the estimated ratios were higher than the reported ratios because the relatively cheaper local coals were less used in all the small cities except in cities where local coal deposits were found nearby. The comparison results showed that moss sulfur isotope is a useful tool for indicating coal-derived sulfur even in cities where mixed coals were combusted.

Epilithic mosses are characterized by insulation from substratum N and hence meet their N demand only by deposited N. This study investigated tissue C, total Chl and delta13C of epilithic mosses along 2 transects across Guiyang urban (SW China), aiming at testing their responses to N deposition. Tissue C and total Chl decreased from the urban to rural, but delta13C(moss) became less negative. With measurements of atmospheric CO2 and delta13CO2, elevated N deposition was inferred as a primary factor for changes in moss C and isotopic signatures. Correlations between total Chl, tissue C and N signals indicated a nutritional effect on C fixation of epilithic mosses, but the response of delta13C(moss) to N deposition could not be clearly differentiated from effects of other factors. Collective evidences suggest that C signals of epilithic mosses are useful proxies for N deposition but further works on physiological mechanisms are still needed., (Copyright 2010 Elsevier Ltd. All rights reserved.)

In urban cities in Southern China, the tissue S/N ratios of epilithic mosses (Haplocladium microphyllum), varied widely from 0.11 to 0.19, are strongly related to some atmospheric chemical parameters (e.g. rainwater SO(4)(2-)/NH(4)(+) ratios, each people SO(2) emission). If tissue S/N ratios in the healthy moss species tend to maintain a constant ratio of 0.15 in unpolluted area, our study cities can be divided into two classes: class I (S/N > 0.15, S excess) and class II (S/N < 0.15, N excess), possibly indicative of stronger industrial activity and higher density of population, respectively. Mosses in all these cities obtained S and N from rainwater at a similar ratio. Sulphur and N isotope ratios in mosses are found significantly linearly correlated with local coal delta(34)S and NH(4)(+)-N wet deposition, respectively, indicating that local coal and animal NH(3) are the major atmospheric S and N sources., (Copyright 2009 Elsevier Ltd. All rights reserved.)

A study of the continuous precipitation in Guiyang has been taken during October 30 and November 7. The results showed that the range of pH was between 3.65 and 7.20, and volume-weighted mean was 4.24. SO4(2-) was the main anion and volume-weighted mean was 119.06 microeq x L(-1), accounting for 80.63% of total anions. While Ca2+ was the main cation and volume-weighted mean was 48.87 microeq x L(-1), accounting for 48.16% of total cation and NH4+ was 38.38 microeq x L(-1), 37.82%. Good correlations between Mg2+, Ca2+, NH4+ and SO4(2-) are observed, which may exist as MgSO4, CaSO4 and (NH4)2SO4 in the rainwater in Guiyang City. Different ions of the atmosphere had different scavenged ways and rate in the precipitation process. In the initial stage of precipitation, the ions such as Mg2+, which were rich in coarse particles, were quickly removed from atmosphere. However the ions such as NH4+ and SO4(2-), which were rich in fine particles, could remain in the atmosphere for a longer time.

The application of geochemical signals in mosses is more and more popular to investigate the deposition of atmospheric pollutants, but it is unclear whether records of atmospheric sulfur in mosses differ between their diverse habitats. This study aimed to investigate the influence of growing condition on tissue sulfur and delta34S of Haplocladium microphyllum. Epilithic and terricolous mosses in open fields, mosses under different canopy conditions were considered. We found that tissue sulfur and delta34S of mosses under different habitats were not consistent and could not be compared for atmospheric sulfur research with each other even collected at the same site, moss sulfur and delta34S records would be distorted by subsoil and upper canopies in different degrees, which possibly mislead the interpretation of atmospheric sulfur level and sources. Consequently, mosses on open rocks can be used reliably to assess atmospheric-derived sulfur in view of their identical sulfur and delta34S evidences.

Nitrate (NO 3 −) is a key component of secondary inorganic aerosols and PM 2.5. However, the contributions of nitrogen oxides (NO x) emission sources to NO 3 − in PM 2.5 remain poorly constrained. This study measured nitrogen (N) isotopes of NO 3 − (hereafter as δ15N-NO 3 -) in PM 2.5 collected at Beijing in 2014. We observed that δ15N-NO 3 - values in PM 2.5 (−2.3‰ − 19.7‰; 7.3 ± 5.4‰ annually) were significantly higher in winter (11.9 ± 4.4‰) than in summer (2.2 ± 2.5‰). The δ15N differences between source NO x and NO 3 − in PM 2.5 (hereafter as Δ values) were estimated by a computation module as 7.8 ± 2.2‰ − 10.4 ± 1.6‰ (8.8 ± 2.4‰). Using the Δ values and δ15N values of NO x from major fossil (coal combustion, vehicle exhausts) and non-fossil sources (biomass burning, microbial N cycle), contributions of major NO x sources to NO 3 − in PM 2.5 were further estimated by the SIAR model. We found that seasonal variations of δ15N-NO 3 - values in PM 2.5 of Beijing were mainly caused by those of NO x contributions from coal combustion (38 ± 10% in winter, 20 ± 9% in summer). Annually, NO x from coal combustion, vehicle exhausts, biomass burning, and microbial N cycle contributed 28 ± 12%, 29 ± 17%, 27 ± 15%, and 16 ± 7% to NO 3 − in PM 2.5 , respectively, showing actually comparable contributions between non-fossil NO x (43 ± 16%) and fossil NO x (57 ± 21%). These results are useful for planning the reduction of NO x emissions in city environments and for elucidating relationships between regional NO x emissions and atmospheric NO 3 − pollution or deposition. Image 1 • δ15N-NO 3 - values of PM 2.5 in Beijing were higher in winter than in summer. • Seasonal δ15N-NO 3 - variations of PM 2.5 were mainly caused by those of NO x emission from coal combustion. • Fossil and non-fossil NO x sources contributed equally to NO 3 − of PM 2.5 in Beijing. Isotope partitioning of major nitrate sources in PM 2.5 [ABSTRACT FROM AUTHOR]