Human health risk due to polycyclic aromatic hydrocarbons in PM 10 and PM 2.5 : a case study at two selected Kindergartens in Hanoi, Vietnam

Abstract Polycyclic aromatic hydrocarbons (PAHs) present in indoor and outdoor particulate matter pose serious health risks, particularly to children. In this study, 32 PM 2.5 and PM 10 samples were collected from two kindergartens in Hanoi, Vietnam, and analyzed using gas chromatography-mass spectrometry. The average concentrations of 16 priority PAHs (Σ16PAHs) were 19.6 and 26.6 ng/m 3 in PM 2.5 and 24.5 and 34.1 ng/m 3 in PM 10 for indoor and outdoor environments, respectively. Significant seasonal variations were observed between the rainy and dry periods. Diagnostic ratios such as Ant/(Ant + Phe), Fla/(Fla + Pyr), and Ind/(Ind + Bper) indicated that petroleum combustion, biomass burning (grass and wood), and coal combustion were the primary sources PAHs. To evaluate health risks, carcinogenic toxicity equivalents (BaP-TEQ), mutagenic toxicity equivalents (BaP-MEQ), and benzo [a]pyrene-equivalent concentrations (B [a]Peq) were calculated. The incremental lifetime cancer risk (ILCR) ranged from 6.22 × 10 −9 (inhalation, in 2023) to 1.83 × 10 −4 (dermal, in 2020), revealing that exposure through ingestion and dermal contact poses a higher cancer risk for children compared to inhalation. These findings underscore the urgent need for improved air quality management and targeted mitigation strategies in preschool environments to mitigate PAH exposure in children’s environments.