Sources of 24-h personal exposure to PM2.5-bound metals: results from a panel study in Wuhan, China
Xing Wang1,2, Bin Wang1,2, Lili Xiao1,2
1Department of Occupational & Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China.
Abstract:
Atmospheric PM2.5-bound metals have been widely addressed, but research on the exposure levels and sources of personal PM2.5-bound metals among urban community residents is limited. The aim of this study is to explore the exposure levels and sources of 24-h personal PM2.5-bound metals among community inhabitants in Wuhan, China. We conducted a penal study of 216 observations with measurements of 16 metals bounded to 24-h personal PM2.5 samples in April-May, 2014, 2017. Analyses of covariance were used to compare PM2.5-bound metal levels across different living habits and ambient conditions. Principal component analysis (PCA) with varimax rotation was performed to explore PM2.5-bound metal sources. Personal PM2.5-bound aluminum (Al) (113.41 ng/m3) showed the highest geometric mean (GM) concentration, followed by lead (Pb) (90.89 ng/m3), zinc (Zn) (67.71 ng/m3), and iron (Fe) (51.85 ng/m3). The elevated levels of PM2.5-bound Al, vanadium (V), manganese (Mn), arsenic (As), rubidium (Rb), cadmium (Cd), and thallium (Tl) were found in participants with cigarette smoke exposure, compared with those without. The concentrations of Rb and strontium (Sr) were positively associated with the time spent outdoors. The increased concentration of nickel (Ni) was found in individuals who spent > 30 min/day in traffic. The elevated levels of V, Mn, and cobalt (Co) were associated with a short distance from dwellings to the main road. The results of PCA showed that PM2.5-bound metals might come from five sources: As, selenium (Se), Rb, Cd, Tl, and Pb from cigarette smoke exposure; Al, V, Mn, Fe, and Sr from crustal dust; copper (Cu) and antimony (Sb) from industrial activities; Ni and Co from traffic emission; and Zn from coal combustion. The concentrations of PM2.5-bound metals in this study were at moderate levels. Cigarette smoke exposure, industrial activities, traffic emission, and coal combustion might be major anthropogenic sources of personal PM2.5-bound metal exposures in Wuhan, China.
