Response of organic aerosol characteristics to emission reduction in Yangtze River Delta region

Highlights

● The emission reduction causes significant change in organic aerosol composition.

● The atmospheric oxidizing capacity improved during emission reduction.

● The mixed oxygenated organic aerosol contributed higher during emission reduction.

Abstract

Organic aerosol (OA) is a major component of atmospheric particulate matter (PM) with complex composition and formation processes influenced by various factors. Emission reduction can alter both precursors and oxidants which further affects secondary OA formation. Here we provide an observational analysis of secondary OA (SOA) variation properties in Yangtze River Delta (YRD) of eastern China in response to large scale of emission reduction during Chinese New Year (CNY) holidays from 2015 to 2020, and the COVID-19 pandemic period from January to March, 2020. We found a 17% increase of SOA proportion during the COVID lockdown. The relative enrichment of SOA is also found during multi-year CNY holidays with dramatic reduction of anthropogenic emissions. Two types of oxygenated OA (OOA) influenced by mixed emissions and SOA formation were found to be the dominant components during the lockdown in YRD region. Our results highlight that these emission-reduction-induced changes in organic aerosol need to be considered in the future to optimize air pollution control measures.

Graphical abstract

Keywords

Emission control / Secondary organic aerosol / Atmospheric oxidizing capacity / Holiday effects / COVID-19 lockdown

References

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Acknowledgements

This work is mainly supported by National Natural Science Foundation of China (No. 42005082). We would like to thank Wenjun Wu and Zheng Xu, who helped maintaining the instruments during the COVID-lock. Also, we thank Liwen Yang and Guangdong Niu for helping data management and thank Xiaolei Wang for sorting the air quality data from national data platform.

Electronic Supplementary Material

Supplementary material is available in the online version of this article at https://doi.org/10.1007/s11783-023-1714-0 and is accessible for authorized users.

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