Characteristics, sources, and health risks of PAHs and their derivatives in indoor dust in Zhengzhou

The occurrence, source, and health risk of polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and oxy-PAHs (OPAHs) in indoor dust collected from three types of microenvironments (offices, classrooms, and dormitories) at a university campus in Zhengzhou were analysed. The results showed that the average concentration of the total PAHs was 2403.21 ± 981.99 ng g⁻¹, with PHE (20.06% of Σ18PAHs) and BkF (15.46%) being the dominant species. The average concentrations of total NPAHs and OPAHs were 11.09 ± 5.12 and 385.80 ± 255.27 ng g⁻¹, with 2+3N-FLT (39.15%) and 9-FLO (39.76%) as the most abundant species of NPAHs and OPAHs, respectively. The average concentrations of total PAHs, NPAHs, and OPAHs in different microenvironments displayed obvious spatial specificity with the highest values in dormitories. The main source of PAHs, as identified by diagnostic ratios, was petroleum combustion, coal/biomass combustion and vehicle exhaust emissions. The average incremental lifetime cancer risk (ILCR) for undergraduates exposed to dust in classrooms and dormitories exceeded 10⁻⁶, indicating a potential cancer risk. The most important exposure pathway was dermal contact, while the inhalation route was negligible.