Ambient Particles (PM10, PM2.5 and PM1.0) and PM2.5 Chemical Components in Western Yangtze River Delta (YRD): An Overview of Data from 1-year Online Continuous Monitoring at Nanjing

Abstract

Understanding particle chemical composition is important in source apportionment and health impact assessment. Since 2012, a Complex Air Pollution Research Station located on the top roof of a 22-floor building (~80 m) in Jiangsu Provincial Academy of Environmental Science was established as a platform to characterize components and temporal variations of hazy and air transport in the region, so as to provide scientific supports on Joint Prevention and Control of Regional Air Pollution control in the Yangtze River Delta. Here, based on 1-year online measurement, we present a preliminary result on occurrence of ambient particles and chemical components, and reconstructed light extinction coefficients based on measured species. In 2015, the annual average concentration of PM2.5 was 68 ± 40 µg/m3, comprising up to nearly 75% of the total PM10. The submicron PM1.0 had an annual average concentration of 48 ± 28 µg/m3 and contributed about 70% of the total PM2.5 mass. Secondary inorganic composition including sulfate, nitrate and ammonium (SNA) was the major fraction of PM2.5, accounting for ~70% on an annual average. The estimated light extinction of ambient particle averaged at 422 ± 256 Mm−1, of which 412 ± 257 Mm−1 was induced by fine PM2.5. SNA contributed largely to the light extinction induced by fine PM2.5 (about 72%), followed by organic matter (18%). During the high-pollution episodes, the mass fraction of SNA increased notably, calling for necessary controls on key gaseous precursors.