Human health risk assessment of heavy metals from PM2.5 in China’s 29 provincial capital cities

After years of governance, China’s PM2.5 pollution has improved significantly, but some problems remain. PM2.5 is the carrier of many heavy metals, and it has a stronger capacity to carry heavy metals, causing more significant harm to public health. At present, most of the studies on PM2.5-bound heavy metals in China are based on individual cities, and there are few studies from China’s provincial capital cities. Given the above reasons, this paper described the pollution characteristics of PM2.5-bound heavy metal (Hg, Pb, Cd, As, Cr(VI), Ni) in 29 provincial capital cities in China (except Hohhot and Lhasa). Furthermore, the human health risk assessment recommended by US EPA was used to evaluate the carcinogenic and non-carcinogenic risks of the male adults, the female adults, and the children. The results indicated that (1) the children were facing a higher risk value of PM2.5-bound heavy metals than the adults; (2) Cr, As, and Pb were the top three elements that contributed to the average non-carcinogenic risk, while Cr(VI), As, and Cd were the three elements with the highest carcinogenic risk; and (3) the concentrations of PM2.5-bound heavy metals in the provincial capital cities of northern China were worse than those in the South. In response to the above conclusions, this paper put forward: (1) the government should strengthen the management of metallurgical industry and coal-burning industrial enterprises; (2) establish a real-time monitoring system for toxic and harmful heavy metal pollutants carried in the atmosphere as soon as possible; (3) concern on the regional synergies to form pollution control metropolitan areas.