Pollution characteristics, source apportionment and health risks assessment of fine particulate matter during a typical winter and summer time period in urban Taiyuan, China

The concentrations of ambient fine particulate matter (PM_2.5) and its compositions in urban Taiyuan, China during a typical winter and summer time period in 2017 were measured to investigate the pollution characteristics, source apportionment and health risks assessment of PM_2.5 pollution. The results demonstrated that the mean daily mass concentration of PM_2.5 in winter (102.6 ± 6.2 μg/m³) was higher than that in summer (65.0 ± 17.2 μg/m³) during sampling. The relatively high concentrations of heavy metals (Zn, Pb, Cu, As, Ni, Cr and Cd), anion (SO₄ ²⁻, NO₃ ⁻, Cl⁻ and F⁻) and high-molecular-weight PAHs in PM_2.5 were observed. The enrichment factors (EFs) values, special diagnostic ratios like ratios of NO₃ ⁻/SO₄ ²⁻ and individual PAHs concentration ratio showed that coal combustion and vehicle emissions were the major sources of PM_2.5 pollution. Health risk assessment illustrated that mean hazard indices for non-cancer and cancer risk of all analyzed metals were within the safe range. However, inhalation exposure to PM_2.5-bound PAHs had carcinogenic risk, while not indicating non-carcinogenic risk. Taken together, although PM_2.5 pollution was alleviated to some extent, PM_2.5 pollution in 2017 was still serious and PM_2.5 was mainly originated from coal burning, especially, in which PM_2.5-bound PAHs in Taiyuan may pose a potential health risk.