PM_2.5 source distribution and transmission analysis in typical polluted cities of Fenwei Plain

Based on HYSPLIT backward trajectory model and NCEP's GDAS data (from March 2019 to February 2020), the seasonal clustering of air mass backward trajectory in Linfen City for 24 hours in winter was simulated, the main pollution sources and pollution transmission channels of PM_2.5 from different source areas were studied, and the seasonal characteristics of different trajectory transmission of PM_2.5 were clarified. Combined with the potential source contribution factor (PSCF) analysis method and the concentration weighted trajectory (CWT) analysis method, the pollution contribution intensity of different pollution source areas to Linfen City was analyzed. The results showed that PM_2.5 pollution in Linfen City was mainly concentrated in winter, followed by spring and autumn, and the lowest in summer. Through the cluster analysis of the backward trajectory of the air mass, it was found that the southwest and northwest directions along Fenhe River Basin were the main pollution transmission channels of air pollution. Through the analysis of potential source contribution and concentration weight trajectory, it was found that the pollution contribution intensity in Hongtong County, Yaodu District, and Xiangfen County of Linfen City was relatively strong, and the surrounding cities of Yulin, Yuncheng, and Jiaozuo had a certain impact on Linfen City.