Health impacts of PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) on children in an industrial city assessed through urinary biomarkers and health risk assessment

This study quantified PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) in residential areas of Ahvaz, Iran, and assessed their potential health impacts on children. Ambient PM2.5 samples were collected from three zones: industrial (Padad), traffic (Golestan), and control (Kianpars). Samples were analyzed for 16 PAHs listed as US EPA priority pollutants. To evaluate internal exposure and biological response, urinary biomarkers (1-hydroxypyrene (1-OHP), 3-hydroxyphenanthrene, 2-naphthol, and creatinine) and pro-inflammatory factors (Immunoglobulin E (IgE) and cytokines (IL-4 and IL-13)) were determined. The Padad area exhibited the highest levels of PM2.5-bound PAHs, dominated by 4-ring (66.1%) and 3-ring (27.74%) compounds. Children residing in Padad had significantly higher urinary PAH metabolites (e.g., 1-OHP: 0.49 ± 0.48 µg/g creatinine; 2-naphthol: 3.22 ± 2.11 µg/g creatinine; p < 0.001) and cytokines (IgE: 134.9 ± 115.7 pg/mL; IL-4: 538.9 ± 456.2 pg/mL; IL-13: 53.6 ± 45.7 pg/mL) than those in Kianpars. Non-carcinogenic (Hazard Quotient, HQ; Hazard Index, HI) and carcinogenic (Incremental Lifetime Cancer Risk, ILCR) risks of PAHs were assessed. All HQinh and HIinh values were < 1, indicating no significant non-carcinogenic risk. HQinh decreased in the order of Nap > Pyr > Fla > Phe > BaP > Ant > Flu > Ace > BghiP. Mean HIinh values were 1.09 × 10−4 (Padad), 5.14 × 10−5 (Golestan), and 1.66 × 10−5 (Kianpars). ILCR values were below 1.0 × 10−6, indicating a negligible carcinogenic risk. These findings indicate increased PAH exposure and inflammation in children from Padad, supporting targeted air-quality interventions. The risk of cancer in children living in industrial areas is 6.55 times higher. PAHs biomarkers in the urine of children living in industrial areas have increased sharply. Blood biomarkers (IgE, IL-4 and IL-13) were investigated. Urinary biomarker levels of children living in industrial areas have increased. Blood biomarker levels of children living in industrial areas have increased.