Journal Article

FZJ-2018-07211

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Atmospheric oxidation capacity in Chinese megacities during photochemical polluted season: radical budget and secondary pollutants formation

Tan, Z. (Corresponding author)FZJ* ; Lu, K. ; Jiang, M. ; Su, R. ; Wang, H. ; Lou, S. ; Fu, Q. ; Zhai, C. ; Tan, Q. ; Yue, D. ; Chen, D. ; Wang, Z. ; Xie, S. ; Zeng, L. ; Zhang, Y.

2018
EGU Katlenburg-Lindau

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Please use a persistent id in citations: http://hdl.handle.net/2128/20371  doi:10.5194/acp-2018-959

Abstract: Atmospheric oxidation capacity is the core of converting fresh-emitted substances to secondary pollutants. In this study, we present the in-situ measurements at four Chinese megacities (Beijing, Shanghai, Guangzhou, and Chongqing) in China during photochemical polluted seasons. The atmospheric oxidation capacity is evaluated using an observational-based model with the input of radical chemistry precursor measurements. The radical budget analysis illustrates the importance of HONO and HCHO photolysis, which contribute nearly half of the total radical primary sources. The radical propagation is efficient due to abundant of NO in the urban environments. Hence, the production rate of secondary pollutants, i.e. ozone and fine particle precursors (H2SO4, HNO3, and ELVOCs) is fast resulting in secondary air pollution. The ozone budget demonstrates that strong ozone production occurs in the urban area which results in fast ozone concentration increase locally and further transported to downwind areas. On the other hand, the O3-NOx-VOC sensitivity tests show that ozone production is VOC-limited, among which alkenes and aromatics should be first mitigated for ozone pollution control in the presented four megacities. However, NOx emission control will lead to more server ozone pollution due to the drawback-effect of NOx reduction. For fine particle pollution, the role of HNO3−NO3− partitioning system is investigated with a thermal dynamic model (ISORROPIA2) due to the importance of particulate nitrate during photochemical polluted seasons. The strong nitrate acid production converts efficiently to nitrate particles due to high RH and ammonium-rich conditions during photochemical polluted seasons. This study highlights the efficient radical chemistry maintains the atmospheric oxidation capacity in Chinese megacities, which results in secondary pollutions characterized by ozone and fine particles.

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Contributing Institute(s):

1. Troposphäre (IEK-8)

Research Program(s):

1. 243 - Tropospheric trace substances and their transformation processes (POF3-243) (POF3-243)

Appears in the scientific report 2018

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Database coverage:
; ; ; NCBI Molecular Biology Database

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