Characteristics, sources, and health risks of trace metals in PM2.5

Objectives: The concentrations and characteristics of trace metals in PM2.5 vary in time and location and can result in various health impacts. The current study aimed to investigate the characteristics and distributions of PM2.5bound trace metals and further identify the possible sources and conduct health risk assessment in Zhejiang, China.Methods: PM2.5 samples were collected during 2015-2019 at seven monitoring sites in Zhejiang, China. Twelve trace metals in ambient PM2.5 were determined. The positive matrix factorization (PMF) model was applied to quantify the potential sources of PM2.5. The chemical daily intake (CDI) via ingestion, exposure concentration (EC) via inhalation and dermally absorbed dose (DAD) via contact were estimated to assess the health risks. Results: The seasonal variations of both PM2.5 and trace metals showed the highest in winter and the lowest in summer. Among the studied trace metals, Aluminum (Al), Lead (Pb) and Manganese (Mn) had the highest concentrations. Soil dust, coal combustion and traffic-related emissions were the main sources of the air pollution at most sites in Zhejiang. Health risk assessment showed that ingestion was the primary exposure pathway, and children were more likely to be affected by ambient trace metals. The non-carcinogenic risks of arsenic (As), Pb, Antimony (Sb) and Thallium (Tl) as well as carcinogenic risks of As, Pb and nickel (Ni) should be paid more attention to.Conclusions: PM2.5-bound trace metals are of great public health concern, particularly related to the potential health risks of As, Pb and Tl. Corresponding emission control measures of metal elements in PM2.5 should be considered.