Spatiotemporal Distribution and Source Attribution of SOA in China

Abstract

Secondary organic aerosol (SOA) is an important pollutant due to its significant impact on atmospheric pollution, climate change and human health. Understanding the source and distribution of SOA is the prerequisite of air pollution control. This study utilized the global chemical transport model MOZART4 (Model for Ozone and Related Chemical Tracers, Version 4) coupled with the parameterizations of SOA multiphase formation, to simulate the spatial and temporal distribution of SOA in China, and analyzed the source contributions of SOA from the aspects of different precursors and regions. Our results indicate that the majority of SOA production happened over the east and the south China due to the availability of SOA precursors, with the summertime production a factor of 2.5 higher than that in winter. Anthropogenic emissions played a dominant role in SOA production, accounting for 55% of SOA source in China, with the rest from biogenic sources (45%). The domestic emissions contributed 77% of SOA production in China, mainly influencing the SOA concentration distribution near the surface of eastern China, especially over North China Plain. Foreign emissions mainly dominated the SOA abundance in western China, especially at higher altitudes mainly due to the rare domestic emission over these areas and the long-range transportation of SOA.