Characterization of short-, medium- and long-chain chlorinated paraffins in ambient PM_2.5 from the Pearl River Delta,...

Research on the environmental occurrence of long-chain chlorinated paraffins (LCCPs) in ambient fine particulate matter (PM_2.5) is still scarce. In the present study, short-chain chlorinated paraffins (SCCPs), medium-chain chlorinated paraffins (MCCPs) and LCCPs were simultaneously quantified and profiled in PM_2.5 samples collected from 96 primary or secondary schools in the Pearl River Delta of South China. SCCPs, MCCPs and LCCPs were detected in higher than 90% samples with concentrations in the range of 0.832-109, 1.02-110, and 0.173-17.4 ng/m³, respectively. The dominant congener groups of SCCPs, MCCPs and LCCPs were C₁₃Cl_6-8, C₁₄Cl_7-8, and C₁₈Cl_7-9, respectively. The concentrations of SCCPs and MCCPs were higher in summer than in winter, while an opposite seasonal trend was observed for LCCPs. Principal components analysis showed there were seasonal variations in the congener group patterns with C₁₃Cl_6-7 and C₁₄Cl₇ more abundant in summer than in winter_. Concentrations of CPs also exhibited slight spatial variations. Exposure risk assessment based on different age groups suggested exposure to PM_2.5-associated CPs would not pose significant health risk. The present study expands the existing knowledge of CPs contamination in atmospheric environment.