Influence of Spring Dust Storm on Atmospheric Particulate-Bound Mercury in a Typical Inland City of Northern China: Characteristics, Sources, and Risk Assessment

Particulate-bound mercury (PBM) has a large dry-deposition rate and removal coefficient, both of which import mercury into terrestrial and marine ecosystems, causing global environmental problems. In order to illustrate the concentration characteristics, main sources, and health risk of PBM in the atmospheric environment during the spring dust storm period in Xi'an in 2022, PM2.5 samples were collected in Xi'an in March 2022. The concentration of PBM and the PM2.5 composition, including water-soluble ions and elements, were analyzed. The input of dust caused a significant increase in the concentration of PBM, Ca2+, Na+, Mg2+, SO42-, and metal elements in the aerosol. The research results revealed that the dust had a strong enrichment influence on the atmospheric PBM in Xi'an. Anthropogenic mercury emissions and long-distance migration in the sand source area promote the rise in PBM concentration and should be included in the mercury inventory. The values of the risk index for a certain metal (Eri) (572.78-1653.33) and the geo-accumulation index (Igeo) (2.47-4.78) are calculated during this study, showing that atmospheric PBM has a strong pollution level with respect to the ecological environment and that Hg mainly comes from anthropogenic mercury emissions. The non-carcinogenic health risk of atmospheric PBM in children (8.48 x 10-2) is greater than that in adults (1.01 x 10-2). The results show that we need to pay more attention to children's health in the process of atmospheric mercury pollution control. This study discusses the distribution characteristics of PBM during spring sandstorms and the effects of atmospheric mercury on residents' health, providing a basis for studying the sustainable development of environmental health and formulating effective strategies for mercury emission control.