Characterization and source apportionment of aerosol light scattering in a typical polluted city in Yangtze River Delta, China

doi:10.5194/acp-2020-176

GSTDTAP > 地球科学

DOI	10.5194/acp-2020-176
	Characterization and source apportionment of aerosol light scattering in a typical polluted city in Yangtze River Delta, China
	Dong Chen, Yu Zhao, Jie Zhang, Huan Yu, and Xingna Yu
	2020-04-28
发表期刊	Atmospheric Chemistry and Physics
出版年	2020
英文摘要	Through online observation and offline chemistry analysis of samples at suburban, urban and industrial sites (NJU, PAES and NUIST respectively) in Nanjing, a typical polluted city in Yangtze River Delta, we optimized the aerosol light scattering estimation method, identified its influencing factors, and quantified the contributions of emission sources to aerosol scattering. The daily average concentration of PM_2.5 during the sampling period (November 2015–March 2017) was 163.1 ± 13.6 μg/m3 for the heavily polluted period, 3.8 and 1.6 times those for the clean (47.9 ± 15.8 μg/m3) and lightly polluted (102.1 ±v16.4 μg/m3) periods, respectively. The largest increase in PM concentration and its major chemical components was found at the size range of 0.56&ndash1.0 μm for the heavily polluted period, and the contributions of nitrate and sulfate were the greatest in the 0.56–1.0 μm fraction (19.4–39.7 % and 18.1–34.7 % respectively) for all the three periods. The results indicated that the large growth of nitrate and sulfate were one of the major reasons for the polluted periods. Based on measurements at the three sites, the US IMPROVE algorithm was optimized to evaluate aerosol scattering in eastern China. The light-absorption capacity OC was estimated to account for over half of the methanol soluble organic carbon (MSOC) at NJU and PAES, whereas the fraction was lower at NUIST. Based on Mie theory, we found that the high relative humidity (RH) could largely enhance the light scattering effect of accumulation particles, but it had few effects on the mixing state of particles. The scattering coefficients of particles within the 0.56–1.0 μm range contributed the most to the total scattering (28–69 %). The mass scattering efficiency (MSE) of sulfate and nitrate increased with the elevated pollution level, whereas a low MSE of organic matter (OM) was found for the heavily polluted period, probably because a proportion of OM had only light-absorption property. A coupled model of positive matrix factorization (PMF) and Mie theory was developed and applied for the source apportionment of aerosol light scattering. Coal burning, industry and vehicles were identified as the major sources of the reduced visibility in Nanjing, with an estimated collective contribution at 64–70 %. The comparison between the clean and polluted period suggested that the increased primary particle emissions from vehicles and industry were the major causes of the visibility degradation in urban and industrial regions, respectively. In addition, secondary aerosols were a great contributor to the reduced visibility.
领域	地球科学
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/248896
专题	地球科学
推荐引用方式 GB/T 7714	Dong Chen, Yu Zhao, Jie Zhang, Huan Yu, and Xingna Yu. Characterization and source apportionment of aerosol light scattering in a typical polluted city in Yangtze River Delta, China[J]. Atmospheric Chemistry and Physics,2020.
APA	Dong Chen, Yu Zhao, Jie Zhang, Huan Yu, and Xingna Yu.(2020).Characterization and source apportionment of aerosol light scattering in a typical polluted city in Yangtze River Delta, China.Atmospheric Chemistry and Physics.
MLA	Dong Chen, Yu Zhao, Jie Zhang, Huan Yu, and Xingna Yu."Characterization and source apportionment of aerosol light scattering in a typical polluted city in Yangtze River Delta, China".Atmospheric Chemistry and Physics (2020).