Sources and processes of organic aerosol in non-refractory PM1 and PM2.5 during foggy and haze episodes in an urban environment of the Yangtze River Delta, China

Shuaiyi Li; Cheng Chen; Guang-Li Yang; Jie Fang; Yele Sun; Lili Tang; Hongli Wang; Wentao Xiang; Hongliang Zhang; Philip L Croteau; John T Jayne; Hong Liao; Xinlei Ge; Olivier Favez; Yunjiang Zhang

doi:10.1016/j.envres.2022.113557

Sources and processes of organic aerosol in non-refractory PM₁ and PM_2.5 during foggy and haze episodes in an urban environment of the Yangtze River Delta, China

Environ Res. 2022 Sep;212(Pt D):113557. doi: 10.1016/j.envres.2022.113557. Epub 2022 May 28.

Authors

Shuaiyi Li¹, Cheng Chen², Guang-Li Yang³, Jie Fang⁴, Yele Sun⁵, Lili Tang², Hongli Wang⁶, Wentao Xiang⁷, Hongliang Zhang⁸, Philip L Croteau⁹, John T Jayne⁹, Hong Liao⁴, Xinlei Ge⁴, Olivier Favez¹⁰, Yunjiang Zhang¹¹

Affiliations

¹ Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, China; State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environment Sciences, Shanghai, China.
² Jiangsu Environmental Monitoring Center, Nanjing, China.
³ Jiangsu Environmental Monitoring Center, Nanjing, China; Huaian Environmental Monitoring Center of Jiangsu Province, Huaian, China.
⁴ Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, China.
⁵ State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.
⁶ State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environment Sciences, Shanghai, China.
⁷ Key Laboratory of Clinical and Medical Engineering, School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing, China.
⁸ Nanjing Xindahanda Environmental Science and Technology Limited, Nanjing, China; Handix LLC, Boulder, CO, USA.
⁹ Aerodyne Research, Inc., Billerica, MA, USA.
¹⁰ Institut National de l'Environnement Industriel et des Risques, Verneuil-en-Halatte, France.
¹¹ Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, China; State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environment Sciences, Shanghai, China. Electronic address: yjzhang@nuist.edu.cn.

PMID: 35640706
DOI: 10.1016/j.envres.2022.113557

Abstract

Organic aerosol (OA) generally accounts for a large fraction of fine particulate matter (PM_2.5) in the urban atmosphere. Despite significant advances in the understanding their emission sources, transformation processes and optical properties in the submicron aerosol fraction (PM₁), larger size fractions - e.g., PM_2.5 - still deserve complementary investigations. In this study, we conducted a comprehensive analysis on sources, formation process and optical properties of OA in PM₁ and PM_2.5 under haze and foggy environments in the Yangtze River Delta (eastern China), using two aerosol chemical speciation monitors, as well as a photoacoustic extinctiometer at 870 nm. Positive matrix factorization analysis - using multilinear engine (ME2) algorithm - was conducted on PM₁ and PM_2.5 organic mass spectra. Four OA factors were identified, including three primary OA (POA) factors, i.e., hydrocarbon-like OA (HOA), cooking OA (COA), and biomass burning OA (BBOA), and a secondary OA (SOA) factor, i.e., oxidized oxygenated OA (OOA). An enhanced PM_1-2.5 COA concentration was clearly observed during cooking peak hours, suggesting important contribution of fresh cooking emissions on large-sized particles (i.e., PM_1-2.5). The oxidation state and concentration of PM_2.5 HOA were higher than that in PM₁, suggesting that large-sized HOA particles might be linked to oxidized POA. High contribution (44%) of large-sized OOA to non-refractory PM_2.5 mass was observed during haze episodes. During foggy episodes, PM₁ and PM_2.5 OOA concentrations increased as a positive relationship over time, along with an exponential increase in the PM_2.5-OOA to PM₁-OOA ratio. Meanwhile, OOA loadings increased with the aerosol liquid water content (ALWC) during foggy episodes. Random forest cross-validation analysis also supported the important influence of ALWC on OOA variations, supporting substantial impact of aqueous process on SOA formation during haze and/or foggy episodes. Obtained results also indicated high OOA contributions (21%-36%) and low POA contributions (6%-14%) to the PM_2.5 scattering coefficient during haze and foggy episodes, respectively. Finally, we could illustrate that atmospheric vertical diffusion and horizontal transport have important but different effects on the concentrations of different primary and secondary OA factors in different particle size fractions.

Keywords: Aerosol light scattering; Aqueous process; Organic aerosol; PM(2.5) ACSM; Sources.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aerosols / analysis
Air Pollutants* / analysis
China
Environmental Monitoring / methods
Particulate Matter / analysis
Rivers

Substances

Aerosols
Air Pollutants
Particulate Matter