Exploring the impact of chemical composition on aerosol light extinction during winter in a heavily polluted urban area of China

Yaqing Zhou; Qiyuan Wang; Xu Zhang; Yichen Wang; Suixin Liu; Meng Wang; Jie Tian; Chongshu Zhu; Rujin Huang; Qian Zhang; Ting Zhang; Jiamao Zhou; Wenting Dai; Junji Cao

doi:10.1016/j.jenvman.2019.06.100

Exploring the impact of chemical composition on aerosol light extinction during winter in a heavily polluted urban area of China

J Environ Manage. 2019 Oct 1:247:766-775. doi: 10.1016/j.jenvman.2019.06.100. Epub 2019 Jul 6.

Authors

Yaqing Zhou¹, Qiyuan Wang², Xu Zhang³, Yichen Wang⁴, Suixin Liu⁵, Meng Wang¹, Jie Tian⁵, Chongshu Zhu⁵, Rujin Huang⁵, Qian Zhang⁶, Ting Zhang⁵, Jiamao Zhou⁵, Wenting Dai⁵, Junji Cao⁷

Affiliations

¹ State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
² State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; University of Chinese Academy of Sciences, Beijing, 100049, China; CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, 710061, China. Electronic address: wangqy@ieecas.cn.
³ Xi'an Environmental Monitor Station, Xi'an, 710100, China.
⁴ College of Management, Shenzhen University, Shenzhen, 518060, China.
⁵ State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, 710061, China.
⁶ School of Environmental & Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
⁷ State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, 710061, China. Electronic address: cao@loess.llqg.ac.cn.

PMID: 31288215
DOI: 10.1016/j.jenvman.2019.06.100

Abstract

An intensive measurement campaign was conducted in Xi'an, China from December 2012-January 2013 to investigate the chemical composition, formation, and optical properties of PM₁. The PM₁ mass concentration (average = 138.8 ± 83.2 μg m^-3) accounted for ∼50% of the PM_2.5 mass. Organic aerosols (OA) and secondary inorganic aerosols (SIA) were the most abundant PM₁ components, contributing 53.0% and 35.0% to the mass, respectively. Both primary emissions and aqueous-phase oxidation of secondary aerosols played roles in the pollution episodes. The average light scattering and absorption coefficients during the campaign were 805 ± 581 Mm^-1 and 123 ± 96 Mm^-1, respectively. Both the mass scattering and mass absorption efficiencies for PM₁ were higher than that for PM_2.5-1, indicating stronger ability of light extinction for the smaller particles at visible wavelengths compared with the larger ones. The contributions of aerosol species to light extinction coefficients under two visibility conditions were estimated based on multiple linear regression models, and the OA was found to be the largest contributor to light extinction in both cases. A larger contribution of SIA to light extinction for visibility <5 km demonstrated its greater impacts on visibility during heavy pollution conditions. These findings provide insights into the importance of submicron particles for pollution and visibility degradation in northwestern China.

Keywords: Aerosol species; Optical properties; PM(1); Pollution formation mechanisms.

MeSH terms

Aerosols
Air Pollutants*
China
Environmental Monitoring
Particulate Matter*

Substances

Aerosols
Air Pollutants
Particulate Matter