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Increasing evidence suggests that the toxicity of fine dust particles (PM 2.5 ) is linked to specific components rather than their mass. However, research on the chemical composition and health risk of PM 2.5 is insufficient. This study analyzed the metals, polycyclic aromatic hydrocarbon (PAHs), organochlorine pesticides (OCPs), and polychlorinated biphenyls (PCBs) present in PM 2.5 and evaluated their risk to health during outdoor activities. The concentration of metals was one order of magnitude higher than that of PAHs and the concentration and detection frequency of OCPs and PCBs were considerably lower than those of metals and PAHs. The lifetime excess cancer risk (LECR) for carcinogens in PM 2.5 exceeded de minimis risk (1 × 10 -6 ) as 1.33-3.44 × 10 -6 (at 5th-95th percentile) as Cr(VI), As, and Cd showed high contributions. Children in the 2 < years <18 age group had a high risk of cancer due to early-life susceptibility. The proportion of ∑Metals to LECR was approximately 95%, while ∑PAHs attributed to 5% of total LECR. The effects of ∑OCPs and 2,3',4,4',5'-Pentachlorobiphenyl (PCB-123) on LECR were negligible. The hazard quotient (HQ) for non-carcinogens was <1, and non-carcinogenic effects were not expected. Mn, BaP, Pb, As, and Cd were the key determinants of the HQ values and among the identified PM 2.5 sources they are closely related to industrial activities, oil combustion, and gasoline exhaust. Therefore, control strategies for these sources can effectively reduce PM 2.5 risk. This study measured the concentrations of toxic compounds in ambient PM 2.5 and considered only PM 2.5 exposure during outdoor activities. PM 2.5 health risk during the entire day would be higher than the PM 2.5 risk determined in this study, and further research is required for this evaluating this risk., (Copyright © 2019 Elsevier B.V. All rights reserved.)