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Estimation of Secondary Organic Aerosol Formation During a Photochemical Smog Episode in Shanghai, China
Author(s) -
Wang Hongli,
Wang Qian,
Gao Yaqin,
Zhou Min,
Jing Shengao,
Qiao Liping,
Yuan Bin,
Huang Dandan,
Huang Cheng,
Lou Shengrong,
Yan Rusha,
Gouw Joost A.,
Zhang Xuan,
Chen Jianmin,
Chen Changhong,
Tao Shikang,
An Jingyu,
Li Yingjie
Publication year - 2020
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2019jd032033
Subject(s) - ozone , environmental chemistry , total organic carbon , aerosol , tracer , atmosphere (unit) , photochemistry , chemistry , environmental science , emission inventory , pollution , volatile organic compound , carbon fibers , air pollution , meteorology , organic chemistry , materials science , ecology , physics , composite number , nuclear physics , composite material , biology
Abstract Secondary organic aerosols (SOA) are formed through diverse processes in the atmosphere, among which photochemical processing is one important pathway. SOA formation was studied based on one heavy photochemical smog episode in summer in Shanghai. During the pollution episode, ozone and organic carbon (OC) increased simultaneously with a strong positive correlation, which was complete opposite to the volatile organic compounds (VOCs) pattern but similar to that of VOC photochemical consumption. The OC evolution was explained well by a parameterization method based on the observation of OC and VOCs, and secondary OC (SOC) formation was derived, being comparable with the result based on elemental carbon (EC) tracer method. About 67% of SOC could be explained by the photochemical consumption of VOCs (mainly aromatics, ~93%) during the episode. The contribution of VOCs to SOC formation was also estimated from the available VOC emissions inventories, which was comparable with that based on VOCs observations in ambient. Some differences of VOC species contribution to SOC were found between the ambient observation‐based and the emission‐based results, and the contribution of C9 aromatics was underestimated in the emission inventory. This suggests that bias of speciation might exist in the current VOC emissions inventories. The present study highlights the importance of VOC oxidation for SOC formation in summer in Shanghai. More insights are needed to improve the accuracy of VOCs speciated emissions inventories.