Investigating the characteristics and source analyses of PM2.5 seasonal variations in Chengdu, Southwest China. (March 2020)

• Record Type: Journal Article
• Authors: Kong, Liuwei; Tan, Qinwen; Feng, Miao; Qu, Yu; An, Junling; Liu, Xingang; Cheng, Nianliang; Deng, Yijun; Zhai, Ruixiao; Wang, Zheng
• Is Part Of: Chemosphere. Volume 243(2020)
• Publication Date: 2020-03
• Subjects: PM2.5 -- Seasonal variation -- Chemical compositions -- Source appointment -- Regional transport -- Sichuan basin; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.125267
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: In 2015, comprehensive observations were carried out in Chengdu, Sichuan Province, China, to elucidate the seasonal variation characteristics of the concentrations, chemical compositions, and the sources of PM2.5 pollution. The meteorological parameters, gaseous pollutants and chemical compositions of PM2.5 were measured. The annual average concentration of PM2.5 in Chengdu was 67.44 ± 48.78 μg/m 3 . The highest seasonal PM2.5 mass concentration occurred in winter with an average of 103.04 ± 66.76 μg/m 3, followed by spring, autumn, and summer, and the wind speed had an important impact on the diffusion of PM2.5 . The seasonal variation characteristics of chemical components in PM2.5 were analysed. The contribution and chemical conversion ability of secondary aerosols increased with increasing of PM2.5 concentration. Source appointment of positive matrix factorization (PMF) shows that the main sources of PM2.5 were secondary aerosols, coal combustion, biomass burning, vehicle emissions, dust and industrial sources, which have more obvious seasonal differences than other sources, and secondary aerosols and coal combustion were the major sources. Conditional probability function (CPF) analysis showed that the local sources of high PM2.5 concentrations were mainly from the eastern and southeastern areas of Chengdu. Potential source contribution function (PSCF), concentration weighted trajectory (CWT) and backward trajectory cluster analyses indicated that the southern, southeast and eastern parts of the Sichuan Basin were the most likely potential sources of PM2.5, and the unique geographical and topographical factors in Chengdu play important roles in the transport and diffusion of pollutants in this region. Highlights: The effect of wind speed on PM2.5 is higher than that of relative humidity. The secondary aerosol chemical conversion ability increases with increasing PM2.5 . Secondary aerosols and coal combustion are the main sources of PM2.5 . Local emission sources in Chengdu are mainly concentrated in the east and southeast. Regional transport comes from the south, southeast and east in the Sichuan Basin.