Characteristics of mass concentration, chemical composition, source apportionment of PM 2.5 and PM 10 and health risk assessment in the emerging megacity in China

Abstract In this study, 228 daily Particulate matter (PM) filters (57 Quartz and 57 Teflon samples for both PM 2.5 and PM 10 , respectively) were collected from an urban site in Zhengzhou in typical months from 2014 autumn to 2015 summer representing the four seasons. PM concentrations, water-soluble inorganic ions, organic carbon, elemental carbon, and elements were determined, and positive matrix factorization was used for source apportionments. Health risks of toxic elements in PM 2.5 and PM 10 were also evaluated. The annual mean values of PM 2.5 and PM 10 were higher than the standards in China, and the highest seasonal concentrations of PM 2.5 and PM 10 were in winter. Secondary inorganic aerosols (SIAs) were the major component, with the ratio of SIAs/PM highest in summer. The seasonal concentrations of SO 4 2− were high in winter and summer. Crustal elements mainly existed in PM 2.5–10 ; however, elements from anthropogenic sources (i.e., Zn, Pb, Cu, As, Cd, and Mo) were more abundant in fine particles than in the coarse fraction. The main pollution sources were dust, SIAs, coal combustion, vehicle and road dust, and industry, accounting for 10%, 26%, 25%, 20% and 15% in PM 2.5 and 32%, 14%, 24%, 18% and 8% in PM 10 , respectively. Dust source has the highest contribution in PM 10 ; however, SIAs source has the highest content in fine particles. The carcinogenic risks of As to children through the daily intake pathway in PM 2.5 and PM 10 exceeded the acceptable level. Noncarcinogenic risks of As and Cd in PM 2.5 and PM 10 to children via the daily intake pathway were significant. Moreover, the sum of noncarcinogenic risks in PM 10 via inhalation exposure for local residents and that via dermal absorption for children were significant. The details of the pollution characteristics and the results of source apportionments and health risks assessment of PM 2.5 and PM 10 in this study can play an important role for the government to formulate reasonable and effective policy to mitigate the atmospheric pollution of PM. To our knowledge, this systematic study is the first to investigate the chemical characterizations, source apportionments, and health effects of PM 2.5 and PM 10 in Zhengzhou.