Spatiotemporal variations and risks assessment of PAH-bound suspended particles across different Asian countries: Insights from multi-city sampling and source apportionment.

Air pollution caused by particulate matter (PM) poses serious health risks globally, particularly in rapidly urbanizing Asian cities, where extreme pollution episodes exhibit distinct chemical profiles and sources due to diverse local anthropogenic activities. This study aims to assess the toxicity and mutagenic characteristics of Polycyclic Aromatic Hydrocarbons (PAHs) originating from particulate matter (PM) in different anthropogenic actives in Asian cities. High-volume samplers were used for ambient PM collection in various Asian cities from 2019 to 2023, and subsequent analyses included PAHs, heavy metals, and water-soluble ions (WSIs). Ecological and inhalation cancer risk assessments were computed by multiplying concentrations of individual PAH compounds in Taipei, Chiang Mai, Hanoi, Ulaanbaatar, and Beijing, respectively. The average concentrations of PM2.5 and PAH BaP-TEQ levels were 132 ± 45.3 μg/m3, 23.0 ± 24.8 ng/m3 in Chiang Mai and 63.3 ± 11.9 μg/m3, 2.81 ± 2.64 ng/m3 in Hanoi, while 12.6 ± 6.02 μg/m3, 4.75 ± 8.88 ng/m3 in Taipei. In Ulaanbaatar, total suspended particles (TSP) and PAH levels during dust storm events were 2.08-8.13 times higher (TSP: 601 μg/m3, PAH: 91.0 ng/m3). Similarly, in Beijing, TSP and PAHs levels were 2.49-10.4 times higher during dust storm events (TSP: 701-1135 μg/m3, PAHs: 27.8 ± 24.6 ng/m3). PMF results revealed 47.5-79.8 % contributions from vehicles in Ulaanbaatar, Chiang Mai, and Hanoi. While ecological risk assessments indicated generally low toxicity (RI < 150), lifetime inhalation cancer risk (LICR) values exceeded the acceptable threshold (10-6) in several cities, highlighting the urgent need for targeted pollution control strategies.