Health Risk Assessment of Passive Air Sampler-derived Polychlorinated biphenyl and Polycyclic Aromatic Hydrocarbons in Bangkok and Chiang Mai, Thailand

Atmospheric pollutants have become a severe problem in creating health issues in Thailand. Due to the increase in fine particles in the air environment, the city population is facing acute respiratory problems. For understanding the concentration of polycyclic aromatic hydrocarbon (PAHs) and Polychlorinated biphenyls (PCBs), sampling was done in Chiangmai and Bangkok of Thailand using Polyurethane (PUF) disk passive samplers. There were five sampling sites in Bangkok, and three in Chiang Mai. Data were collected in the dry season, i.e. from December 2018- June 2019. A total of 24 samples were extracted and further quantitatively analyzed by the standard method using GC-MS. Both PAHs and PCBs concentrations increased during the dry season. At Chiang Mai, max. PAHs were found to be 848 ng/m
³
, which was higher than that of Bangkok, max. PAHs concentration was found to be 455 ng/m
³
. On the other hand, the max PCBs found in Bangkok were 15 pg/m
³
were higher than that in Chiang Mai (max. value 2.63 pg/m
³
, Chiang Mai sites had more dominant species PAHs than in Bangkok, particularly during forest fire episodes from February to April 2019. The potential sources of PAHs were found as the combined emission of diesel and gasoline vehicles and biomass combustion. The carcinogenic risk associated with inhalation exposure to PAHs and PCBs was estimated to be
$< \mathbf{10}^{-\mathbf{6}}$
at all the sampling points. The analyzed PAHs and PCBs species indicated their potential sources that related to both biomass burning and traffic in Bangkok and Chiangmai. Pollutants' level also had seasonal variations. Therefore, air quality management is an essential issue that needs to be monitored in these provinces (cities) of Thailand.