Characteristics and Sources Analysis of Element in Ambient PM2.5 in Taiyuan City

In 2017-2018, the concentrations and sources of ambient fine particulate matter (PM2.5) and its 15 elements (Al, As, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, V, Zn) in three sampling points (Jiefang North Road Jiancaoping District, Xinjian South Road and Shuangtasi Street Yingze District) in Taiyuan city were investigated during the non-heating season, the light pollution period in heating season and the heavy pollution period in heating season. The samples were collected continuously by medium flow particle samplers in 6 days with more than 20 hours each day, and the concentrations of the 15 elements were determined by ICP-MS after pretreatment of microwave digestion. The spatial and temporal distribution characteristics were analyzed by descriptive statistical method. The main sources of PM2.5 were analyzed by enrichment factor method (EF) and the principal component analysis method (PCA). The concentrations of PM(2.5 )and its 15 elements showed the tendency of the heavy pollution period in heating season > the light pollution period in heating season > the non-heating season. There were no significant differences in concentrations of PM2.5 and most of the 15 elements between the 3 sampling points (p<0. 01). The main sources of the 15 elements in the non-heating season was soil, construction and metallurgical industry with the contribution of 32.03%, 30.52% and 18.26%. The main sources in the light pollution period in heating season was the mixed source of construction, soil and metallurgical industry, the mixed source of construction and biomass combustion and soil with the contribution of 37.98%, 37.05% and 16.55%. The main sources in the heavy pollution period in heating season was the mixed source of construction and biomass combustion, the mixed source of construction, soil and metallurgical industry and soil with the contribution of 40.62%, 35.52% and 13.96%. Compared with previous studies, the results of this research showed that although the control measures of PM2.5 in Taiyuan had been effective in recent years, the management and control of pollution sources such as metallurgical industry, motor vehicles and coal burning should be further strengthened.