Pollution Characteristics, Chemical Compositions, and Population Health Risks during the 2018 Winter Haze Episode in Jianghan Plain, Central China

Abstract

To determine the pollution characteristics, chemical compositions, and population health risks of PM_2.5 at different pollution levels, PM_2.5 samples were intensively collected during the long-lasting winter haze episode from 13–23 January 2018 in Xiantao in Jianghan Plain (JHP), central China. The higher PM_2.5 levels during the severe pollution period were dominated by the WNW-NNE air-masses, whereas the lower PM_2.5 concentrations during other pollution periods were mainly affected by the NE, S, and NW air-masses. The NO₃⁻/SO₄²⁻ and OC/EC ratios indicated a mixed contribution of intensive vehicle exhaust and secondary formation. The enrichment factor and geo-accumulation index for assessing the PM_2.5-bound metal(loid)s contamination levels were positively correlated. Ingestion is the dominant exposure pathway of PM_2.5-bound metal(loid)s for children and adults, followed by inhalation and dermal contact. As, Cr, and Pb may pose carcinogenic and non-carcinogenic risks, whereas Sb and V may only pose non-carcinogenic risks for children and adults. The population health risks may not depend on the pollution levels but depend on the PM_2.5-bound metal(loid)s concentrations. PM_2.5-bound metal(loid)s may pose much higher population health risks for adults compared to children. More attentions should be paid to the population health risks of PM_2.5-bound metal(loid)s during a long-lasting winter haze episode in JHP.