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Ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations were performed from 27 December 2018 to 16 January 2019 in Changshou, one of subdistricts of Chongqing, China. Primary atmospheric pollutant in Changshou during wintertime was PM 2.5 , whose contribution averaged about 70.15% ± 9.5% of PM 10. The ratio of PM 2.5 /PM 10 decreased when PM 2.5 pollution became worse, and it should attribute to biomass burning and the contribution of hygroscopic growth and enhanced heterogeneous chemistry under high relative humidity condition. Moreover, nitrogen dioxide (NO 2), formaldehyde (HCHO) and glyoxal (CHOCHO) vertical profiles during the campaign period were retrieved separately. TROPOMI HCHO vertical column densities (VCDs) and MAX-DOAS HCHO VCDs were correlated well (R = 0.93). In order to identify the sources of volatile organic compound (VOC) in Changshou, the ratio of CHOCHO to HCHO (R GF) in five different layers were estimated. The estimated daily averaged R GF were 0.0205 ± 0.0077, 0.0727 ± 0.0286, 0.0864 ± 0.0296, 0.0770 ± 0.0275 and 0.0746 ± 0.0263 in 0–100 m, 100–200 m, 300–400 m, 500–600 m and 700–800 m layers, respectively. The estimated R GF will increase when biomass burnings were dominated. Using NO 2 as a tracer of anthropogenic emissions, we found the R GF values gradually decrease with the increase of NO 2 levels. R GF values in 0–100 m layer and all the other upper layers are 0.015–0.025 and 0.06–0.14, and that means the dominant sources of VOCs in 0–100 m layer and all the other upper layers are biogenic emission and anthropogenic emission (especially biomass burning), respectively. In addition, we found that R GF has site dependence which is in compliance with several previous studies. Unlabelled Image • The ratio of PM 2.5 /PM 10 decreased when PM 2.5 pollution became worse • HCHO and CHCOHO mainly distributed in 0-100 m and 100-200 m, respectively. • The sources of VOCs above 100 m are mainly from biomass burning. [ABSTRACT FROM AUTHOR]

Carbonaceous aerosols have adverse effects on both human health and the climate. To understand the temporal variations and sources of carbonaceous aerosols, organic carbon (OC) and elemental carbon (EC) were measured hourly in suburban Shanghai in 2015–2017 during winter. The average OC concentrations were 7.34 ± 4.51 μgC/m3 in 2015, 7.16 ± 4.43 μgC/m3 in 2016, and 6.4 ± 3.22 μgC/m3 in 2017. The EC concentrations decreased significantly each year, with average concentrations of 3.82 ± 2.43, 2.91 ± 2.28, and 2.46 ± 1.88 μgC/m3, respectively, which caused the OC/EC ratio to increase from 2015 to 2017. Although the meteorological conditions differed each winter, there was a similar pattern of OC and EC diurnal variations, with concentrations peaking at 08:00 and 20:00, largely due to rush-hour vehicle emissions. A downward trend of EC/CO and EC/NO 2 (mass ratios) but steady CO and NO 2 concentrations from 2015 to 2017 revealed that the characteristics of primary vehicle emissions changed, and that less EC was emitted. Secondary organic carbon (SOC) and primary organic carbon (POC) were estimated with the minimum R 2 (MRS) method. The hiemal SOC/OC values in suburban Shanghai were 19.2 ± 18.6% in 2015, 31.1 ± 18.6% in 2016, and 51.0 ± 21.4% in 2017, exhibiting an increasing trend. As the PM 2.5 concentration increased (from 0 to 50 μg/m3 to 100–300 μg/m3), a decreasing SOC/OC ratio (from 43.6 ± 23.9% to 21.8 ± 17.7%) was observed over the three years, showing that primary emissions were the main contributors to carbonaceous aerosols on haze days. Case analysis of haze events further demonstrated that the primary sources of OC and EC were vehicle emissions. The contributions of biomass burning and coal combustion to carbonaceous aerosols became less important over the study period. This study highlights the importance of controlling vehicle emissions to reduce carbonaceous aerosol concentrations in the suburbs of the Chinese megacity, Shanghai. Image 1 • Hourly OC and EC were analyzed at suburban Shanghai in winter 2015 to 2017. • SOC/OC decreased with increased PM 2.5 pollution. • Biomass burning and coal combustion contribution to OC and EC decreased. • Vehicle emissions are the dominant source of carbonaceous aeorosols. [ABSTRACT FROM AUTHOR]

Since the concentrations of primary particles and secondary inorganic aerosol components have been reduced significantly due to stringent emission controls, quantifying the source contributions and regional transport of secondary organic aerosol (SOA) is critical to further improve air quality in eastern China. In this study, the Community Multiscale Air Quality (CMAQ) model coupled with the updated SAPRC-11 photochemical mechanism and a revised SOA module was applied to investigate the emission sector and regional contributions to SOA in winter 2015 (January 5–26, 2015) and 2016 (December 20, 2015–January 20, 2016) in the Yangtze River Delta (YRD). The model is generally capable of reproducing the observed SOA concentrations at the Qingpu Supersite in Shanghai. The observed and predicted SOA concentrations are 6.4 μg/m3 and 6.9 μg/m3 in winter 2015, and 5.7 μg/m3 and 9.6 μg/m3 in winter 2016. The mean fraction bias (MFB) of the hourly SOA predictions is 0.22 and 0.32, respectively. High SOA concentrations in the wintertime of YRD are mainly due to aromatic compounds and dicarbonyls (glyoxal and methylglyoxal), which, on average, account for 43% and 53% of total SOA, respectively. The average contributions of industrial, residential, and transportation sectors in the YRD region during the entire simulation periods are 61%, 22%, and 17%, respectively. At the Qingpu Supersite in Shanghai, the industrial sector contributes to as much as 65% of total SOA in the heavy pollution episode of 2016. The contributions from transportation and residential sectors are 16% and 17%, respectively, during the same episode. The industry emissions from the Jiangsu, Zhejiang, and Shanghai are major contributors to the SOA at the Qingpu supersite during the heavy-polluted episodes, accounting for 31%, 19%, and 14% of the total predicted SOA. This study represents the first detailed regional modeling study of source region contributions to SOA in the YRD region and the detailed analyses of SOA in two winters months complement the previous SOA source apportionment studies focusing on seasonal average contributions. Unlabelled Image • Formation path and source region contributions to SOA in the YRD region were investigated. • Industry source in the YRD region dominates total SOA during the heavy polluted episodes. • Reginal control policy should be considered in the VOCs and SOA reduction in YRD. [ABSTRACT FROM AUTHOR]

Systemic inflammation is considered one of the key mechanisms in the development of cardiovascular diseases induced by fine particulate matter (PM 2.5) air pollution. However, evidence concerning the effects of various PM 2.5 constituents on circulating inflammatory biomarkers were limited and inconsistent. To evaluate the associations of short-term exposure to a variety of PM 2.5 constituents with circulating inflammatory biomarkers. We conducted a panel study from May to October 2016 among 40 healthy adults in Shanghai, China. We monitored the concentrations of 27 constituents of PM 2.5. We applied linear mixed-effect models to analyze the associations of PM 2.5 and its constituents with 7 inflammatory biomarkers, and further assessed the robustness of the associations by fitting models adjusting for PM 2.5 mass and/or their collinearity. Benjamini-Hochberg false discovery rate was used to correct for multiple comparisons. The associations of PM 2.5 were strongest at lag 0 d with tumor necrosis factor- α (TNF-α), at lag 1 d with interleukin-6, interleukin-8, and interleukin-17A, at lag 02 d with monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule-1 (ICAM-1). After correcting for multiple comparisons in all models, Cl−, K+, Si, K, As, and Pb were significantly associated with interleukin-8; SO 4 2− and Se were marginally significantly associated with interleukin-8; SO 4 2−, As, and Se were marginally significantly associated with TNF- α ; and Si, K, Zn, As, Se, and Pb were marginally significantly associated with MCP-1. Our results suggested that some constituents (SO 4 2−, Cl−, K+, and some elements) might be mainly responsible for systemic inflammation triggered by short-term PM 2.5 exposure. Unlabelled Image • It remains unclear how PM 2.5 constituents affect systemic inflammation differently. • 27 constituents and 7 inflammatory biomarkers were evaluated in Shanghai, China. • SO 4 2−, Cl−, K+ and some elements may be responsible for inflammation. [ABSTRACT FROM AUTHOR]

Ground-level ozone (O3) pollution is still one of the priorities and challenges for air pollution control in the Yangtze River Delta (YRD) region of China. Understanding the relationship of O3 with its precursors and contributions of different sources in O3 formation is essential for the development of an O3 control strategy. This study analyzed O3 sensitivity to its precursors using a box model based on online observations of O3, non-methane hydrocarbons (NMHCs), nitrogen oxides (NOx), and carbon monoxide (CO) at an urban site and a suburban site in Shanghai in July 2017. Anthropogenic sources of NMHCs were identified using the positive matrix factorization (PMF) receptor model, and then contributions of different sources in O3 formation were estimated by the observation-based model (OBM). The relative incremental reactivity (RIR) values calculated by the OBM suggest that O3 formation at the urban site was in the NMHC-limited regime, while O3 formation at the suburban site tended between the transition regime and the NMHC-limited regime. Vehicular emission and liquefied petrochemical gas (LPG) use or aged air mass were found to be the two largest contributors at the urban and suburban sites in July, followed by paint and solvent use, and the petrochemical industry. However, from the perspective of O3 formation, vehicular emission and paint and solvent use were the largest two contributors at two sites due to the higher RIR values for paint and solvent use. In addition, the influence of transport on O3 sensitivity was identified by comparing O3 sensitivity at the suburban site across two days with different air mass paths. The result revealed that O3 formation in Shanghai is not only related to local emissions but also influenced by emissions from neighboring provinces. These findings on O3–NMHC–NOX sensitivity, contributions of different sources in O3 formation, and influence of transport could be useful for O3 pollution control in the YRD region. Nevertheless, more quantitative analyses on transport and further evaluation of the uncertainty of the OBM are still needed in future. [ABSTRACT FROM AUTHOR]

Portable air pollutant monitors onboard unmanned aerial systems (UAS) are increasingly being used to make vertical observations within the lower part of the troposphere. An overall evaluation of the UAS platform is critical before its wide application. To our knowledge, these evaluations have rarely been reported. This study is aimed at evaluating the performance of a fixed-wing UAS platform that is deployed with portable ozone (O 3) and fine particulate matter (PM 2.5) monitors. A tethered airship platform deployed with conventional O 3 and PM 2.5 monitors was used as a reference method to evaluate the UAS platform. To obtain custom calibration factors, the portable monitors were evaluated primarily with respect to corresponding conventional monitors at the ground level in three atmospheric environments. Then, the UAS assessment experiment was conducted over a coastal area in Shanghai, China. Seven statistical metrics were used to assess the performance of the portable monitors on the UAS platform. The results revealed that the portable monitors were capable of accurately capturing temporal variations in air pollutant concentrations after custom calibrations. The UAS platform could also accurately capture the vertical variations in O 3 and PM 2.5 concentrations within the lower troposphere. However, significant discrepancies between the UAS and airship platforms were observed for both O 3 and PM 2.5 measurements within the planetary boundary layer (PBL). The relative humidity (RH) values measured in this layer demonstrated significantly larger vertical variations and were substantially larger than those above the PBL. The discrepancies between the two platforms were associated mainly with horizontal variations in the UAS measurements over the experimental area, as well as large vertical variations in ambient temperature and RH within the lower troposphere. • Portable O 3 and PM 2.5 monitors were deployed on an UAS platform. • Portable monitors agree well with conventional monitors in temporal variations. • The fixed wing UAS platform was evaluated against a tethered airship platform. • The UAS platform could well capture the vertical variations in both O 3 and PM 2.5. [ABSTRACT FROM AUTHOR]

The identification of constituents of fine particulate matter (PM 2.5) air pollution that had key impacts of ischemic stroke (the predominant subtype of stroke) is important to understand the underlying biological mechanisms and develop air pollution control policies. To explore the associations between PM 2.5 constituents and hospitalization for ischemic stroke in Shanghai, China. We conducted a time-series study to explore the associations between 27 constituents of PM 2.5 and hospitalization for ischemic stroke in Shanghai, China from 2014 to 2016. The over-dispersed generalized additive models with adjustment for time, day of week, holidays, and weather conditions were used to estimate the associations. We also evaluated the robustness of the effect estimates for each constituent after adjusting for the confounding effects of PM 2.5 total mass and gaseous pollutants and the collinearity (the residual) between this constituent and PM 2.5 total mass. We also compared the associations between seasons. In total, we identified 4186 ischemic stroke hospitalizations during the study period. The associations of ischemic stroke were consistently significant with elemental carbon and several elemental constituents (Chromium, Iron, Copper, Zinc, Arsenic, Selenium, and Lead) at lag 1 day in single-constituent models, models adjusting for PM 2.5 total mass or gaseous pollutants and models adjusting for collinearity. The associations were much stronger in cool season than in warm season. The current study provides suggestive evidence that elemental carbon and some metallic elements may be mainly responsible for the risks of ischemic stroke hospitalization induced by short-term PM 2.5 exposure. Unlabelled Image • Few evidence on the associations between PM 2.5 constituents and ischemic stroke • The effects of PM 2.5 on ischemic stroke hospitalizations varied by constituents. • Elemental carbon and some trace elements might be mainly responsible. [ABSTRACT FROM AUTHOR]

Few studies have investigated respiratory effects of particulate matter air pollution using a full range of particle size distribution. To explore the short-term associations between size-fractionated particle number concentration (PNC) and chronic obstructive pulmonary disease (COPD) mortality. We conducted a time-series study to explore the associations between size-fractionated PNC and daily COPD mortality in the Pudong New Area of Shanghai, China, from 2014 to 2016. We evaluated particle size distribution from 0.01 μm to 10 μm, which was segregated into 7 ranges to better explore the size-dependent associations. We used over-dispersed generalized additive models to estimate the associations after controlling for time trends, temperature, humidity, day of the week and holidays. A total of 5430 deaths due to COPD were identified during the study period. For size ranges from 2.5 – 10 μm, 1–2.5 μm to 0.3–1 μm, there were stronger associations between PNC and COPD mortality, but the associations were statistically insignificant. However, for the smaller size ranges from 0.3 to 0.01 μm, the associations became statistically significant and the magnitude of association remained stable. An interquartile range increase in PNC at lag 0–1 day for size ranges 0.01–0.03 μm, 0.03–0.05 μm, 0.05–0.1 μm and 0.1–0.3 μm was associated with increments of 4.44% (95% CI: 1.16%, 7.73%), 4.31% (95% CI: 1.16%, 7.47%), 4.22% (95% CI: 1.05%, 7.40%), and 4.28% (95% CI: 0.48%, 8.09%) in COPD mortality, respectively. This study suggested that particles below 0.3 μm in diameter might be mainly responsible for the adverse effect of particulate air pollution on CDPD mortality in Shanghai, China. • A study linking a full range of particle size distribution and COPD mortality. • The associations generally increased with smaller particle size. • Particles below 0.3 μm in diameter may be mainly responsible for the associations. • Particles above 0.3 μm in diameter showed no significant associations. [ABSTRACT FROM AUTHOR]

Fine particulate matter (PM 2.5) has been widely associated with airway inflammation represented by increased fractional concentration of exhaled nitric oxide (FeNO). However, it remains unclear whether various PM 2.5 constituents have different impacts on FeNO and its production process from the arginase (ARG)–nitric oxide synthase (NOS) pathway. To investigate the acute effects of PM 2.5 constituents on FeNO and DNA methylation of genes involved. We conducted a longitudinal panel study among 43 young adults in Shanghai, China from May to October in 2016. We monitored the concentrations of 25 constituents of PM 2.5. We applied the linear mixed-effect model to evaluate the associations of PM 2.5 constituents with FeNO and DNA methylation of the ARG2 and NOS2A genes. Following PM 2.5 exposure, NOS2A methylation decreased and ARG2 methylation increased only on the concurrent day, whereas FeNO increased most prominently on the second day. Nine constituents (OC, EC, K, Fe, Zn, Ba, Cr, Se, and Pb) showed consistent associations with elevated FeNO and decreased NOS2A methylation or increased ARG2 methylation in single-constituent models and models adjusting for PM 2.5 total mass and collinearity. An interquartile range increase of these constituents was associated with respective decrements of 0.27–1.20 in NOS2A methylation (%5mC); increments of 0.48–1.56 in ARG2 methylation (%5mC); and increments of 7.12%–17.54% in FeNO. Our results suggested that OC, EC, and some metallic elements may be mainly responsible for the development and epigenetic regulation of airway inflammatory response induced by short-term PM 2.5 exposure. • It remains unclear how PM 2.5 constituents affect airway inflammation differently. • We evaluated the effects of 25 constituents in a panel study in Shanghai, China. • PM 2.5 was associated with increased FeNO and altered methylation for genes involved. • OC, EC and some metallic elements may be responsible for airway inflammation. [ABSTRACT FROM AUTHOR]

Atmospheric ammonia (NH3) has great environmental implications due to its important role in ecosystem and global nitrogen cycle, as well as contribution to secondary particle formation. Here, we report long-term continuous measurements of NH3 at different locations (i.e. urban, industrial and rural) in Shanghai, China, which provide an unprecedented portrait of temporal and spatial characteristics of atmospheric NH3 in and around this megacity. In addition to point emission sources, air masses originated from or that have passed over ammonia rich areas, e.g. rural and industrial sites, increase the observed NH3 concentrations inside the urban area of Shanghai. Remarkable high-frequency NH3 variations were measured at the industrial site, indicating instantaneous nearby industrial emission peaks. Additionally, we observed strong positive exponential correlations between NH4+/(NH4++NH3) and sulfate-nitrate-ammonium (SNA) aerosols, PM2.5 mass concentrations, implying a considerable contribution of gas-to-particle conversion of ammonia to SNA aerosol formation. Lower temperature and higher humidity conditions were found to favor the conversion of gaseous ammonia to particle ammonium, particularly in autumn. Although NH3 is currently not included in China's emission control policies of air pollution precursors, our results highlight the urgency and importance of monitoring gaseous ammonia and improving its emission inventory in and around Shanghai. [ABSTRACT FROM AUTHOR]