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Because of their unintentional formation and low vapor pressure, polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives (XPAHs) in the atmosphere are distributed primarily to aerosolized particles with an aerodynamic diameter less than 2.5 μm (PM 2.5 ). However, no information is available regarding the occurrence of PM 2.5 -bound PAHs and XPAHs in Bangladesh, one of the most highly PM 2.5 -polluted regions worldwide. In this study, we investigated the occurrence of PM 2.5 -bound PAHs and XPAHs in the atmospheres of Dhaka in Bangladesh and Shizuoka in Japan (as a reference) and estimated their incremental lifetime cancer risks (ILCRs). In addition, we statistically estimated the potential sources of PM 2.5 -bound PAHs and XPAHs by using principal component analysis and positive matrix factorization. The median concentration of total PM 2.5 -bound PAHs and XPAHs in Bangladesh was 24.2 times that in Japan. The estimated potential sources of PAHs clearly differed between Japan and Bangladesh, whereas those of XPAHs were largely (>80%) unknown in both countries. The median ILCR in Bangladesh was 2.81 × 10 -3 , which greatly exceeded the upper limit of acceptable risk (10 -4 ). These results indicate that comprehensive monitoring and control of atmospheric PM 2.5 -bound PAHs and XPAHs are needed urgently, especially in highly polluted countries., (Copyright © 2021 Elsevier Inc. All rights reserved.)

A survey of polycyclic aromatic hydrocarbons (PAHs) in residential air in Hangzhou, China, was carried out. Air samples were collected from indoor and outdoor environments during both summer and winter and analyzed for the level of 16 PAHs. The results showed total PAH contents ranging from 0.425 to 36.2 microg/m(3) with highest concentrations in the kitchen areas generally. Particulate PAHs were predominantly absorbed on PM(2.5) with proportion of 59-97% to total particulate phase, followed by PM(2.5-10) (3-24%) and PM(>10) (0-17%). PAH concentrations in indoor air of smoking residences tended to be higher than those of nonsmoking residences. Outdoor environment, Chinese conventional cooking practice, mothball emission and unknown source accounted for -10.5%, 32.8%, 71.5% and 6.2% of total PAHs in indoor air of nonsmoking residences, respectively. Outdoor environment was the fate for indoor PAHs in general, and consumed 10.5% of total PAHs. Finally, health risks associated with the inhalation of PAHs were assessed, and the results indicated that health-based guideline levels for lung cancer risk were exceeded. The largest contribution to total health risks in summer and winter was NA (72.9%) and BaP (45.2%), respectively.