Analysis of Chemical Components and Sources of PM2.5 During Autumn and Winter in Yangquan City

Abstract

PM2.5 samples were collected from October 15, 2017 to January 23, 2018 in the Yangquan urban area. The characteristics of PM2.5 and its main chemical components on clean and polluted days were analyzed, and source apportionment of PM2.5 was conducted using enrichment factor analysis (EF) and positive matrix factorization (PMF). The results showed that the ratios of secondary inorganic ions (SO42-, NO3-, and NH4+) to PM2.5 on polluted days was 23.83%, which is 2.43 times higher than that on clean days, indicating that secondary inorganic pollution was more significant on polluted days. The enrichment degree of anthropogenic elements Cd, Sb, Sn, Cu, Pb, Zn, and As on polluted days was higher than that on clean days. The results of the PMF source apportionment showed that the main sources of PM2.5 in Yangquan are coal combustion, dust, motor vehicles, secondary aerosols, and industry, with contributions of 29.26%, 23.83%, 19.34%, 16.01%, and 11.57%, respectively. The contribution of motor vehicle emissions to PM2.5 on polluted days is 20.57%, which is higher than that on clean days (17.82%), while the contribution of coal combustion sources to PM2.5 on polluted days is 23.04%, which is significantly lower than that on clean days (33.75%). The stationary weather on polluted days caused the contribution of motor vehicle emissions to PM2.5 to increase compared with on clean days, while the contribution of coal combustion sources to PM2.5 was decreased. The results show that air pollution control should pay more attention to the control of coal combustion and dust during autumn and winter in Yangquan, and further strengthen the control of motor vehicles to reduce their contribution to pollution.