Contamination characteristics, mass concentration, and source analysis of metal elements in PM2.5 in Lanzhou, China

Abstract

PM_2.5 and its bound metals pose a serious threat to human health. Understanding their contamination characteristics and source could provide implication for controlling their spreading and ensuring air quality. In this article, 1,600 of PM_2.5 samples were collected from 5 urban sites in Lanzhou, China. The contamination characteristics of PM_2.5, its relationship with meteorological factors, and the source of its bound metals were studied based on multiple linear regression analysis, enrichment factor (EF), principal component analysis and correlation analysis. The outcomes show that the PM_2.5 concentrations in winter (0.117 mg·m^–3) and spring (0.083 mg·m^–3) are higher than those in summer (0.043 mg·m^–3) and autumn (0.048 mg·m^–3). The influence degree of meteorological factors on PM_2.5 concentration is in the order of wind speed > atmospheric pressure > temperature > humidity. The major source of Fe and Cu in PM_2.5 is construction dust, Pb and As is industrial, and Hg is coal combustion. In addition, Cd, V, Co, and Mn are mainly derived from dust produced by weathering of soil or rock. In general, the spatiotemporal distribution of PM_2.5 and its bound metals are different, which is closely related to geographical location, source, and meteorological factors. The results in this article could provide support for the scientific formulation to prevent air pollution in Lanzhou.