Spatial distribution of PM_2.5-bound elements in eighteen cities over China: policy implication and health risk assessment

In this study, 30 elements in fine particulate matter (PM_2.5) were measured in 18 Chinese cities in 2013. Elemental pollution in northern, southwest, and central China were severe, attributing to excessive coal and biomass combustion in these regions. The concentrations of S, Cl, and K in these areas were 8.21 ± 3.90, 4.03 ± 1.96, and 1.59 ± 0.613 μg/m³, respectively, which were 1.6–2.7 times higher than those in other regions of China. In addition, the industrial emissions in northeast and north China were large, leading to the elevated heavy metal concentration of 1.32 ± 1.17 μg/m³, especially Zn, Pb, Cr, Cd, and Br. Soil dust was the highest in northwest China among the five regions with the concentration of crustal elements of 6.37 ± 4.51 μg/m³. Moreover, although the levels of elemental concentration in east and southeast China were relatively acceptable, regulators must pay attention to elevated level of V (0.009 ± 0.006 μg/m³) in these areas. Compared with 2003, several elements have deteriorated in some cities. For example, As increased by 70%, 18%, and 155% in Changchun, Beijing, and Jinchang, respectively. However, ~ 77% measured elements, e.g., Ti, Fe, and Pb markedly reduced in 2013, with reduction rates of 13–81%. These indicate that the government’s policies related to particle-bound elements have shown certain positive environmental effects. For the health risks from the heavy metals in 2013, the non-cancer risks of As and Cd must not be neglected. The cancer risks of As and Pb were much higher than the international safety limit (10⁻⁴). More prominent health risks were found in southwest, central, and northwest China. Therefore, the government should accelerate the shift to cleaner energy in underdeveloped areas of China to obtain more environmental and health benefits.