Understanding Secondary Particle Formation in a Regional Site of Yangtze River Delta: Insights from a High-Resolution Aerosol Mass Spectra

Abstract

Submicron particulate matter (PM1) poses significant risks to health risks and global climate. In this study, secondary organic aerosols (SOA) and inorganic compositions were examined for their physicochemical characteristics and evolution using high-resolution aerosol instruments in Changzhou over one-month period. The results show that transport accompanied by regional static conditions leaded to the occurrence of heavy pollution, besides, regional generation and local emissions also leaded to the occurrence of light and moderate pollution during the observation period in Changzhou. Organic aerosols (OA) accounted for 45% and nitrate (NO3-) for 23% of PM1. The increase in PM1 was dominated by the contribution of NO3- and OA. SOA was dominance in OA, which was higher than primary organic aerosols (POA). Besides, photochemical reactions and the high oxidizing nature of the urban atmosphere promote the production of SOA and NO3- in Changzhou. Our results highlight that secondary particles contribute significantly to PM pollution in Changzhou, underlining the importance of controlling emissions of gaseous precursors, especially under high oxidation conditions.

Keywords: Chemical composition, Secondary organic aerosol, Nitrate, AMS