Significantly Increased Accumulations of PAHs in Scalp Hair During Smoke-haze Period Among Female Adolescents in Chiang Mai, Thailand

Limitations in reporting polycyclic aromatic hydrocarbons (PAHs) accumulated in humans arise from the impact of intense biomass burning and air pollution in upper Southeast Asia. This study analyzed PAHs in human hair samples and explored the associations between ambient PM2.5 and hair PAH concentrations. Follow-up hair collections were conducted on 111 female students, and hair samples with a length of 4 cm were analyzed. Ten different PAHs were identified in the subjects' hair samples. The most substantial pooled estimate of cumulative effects of PM2.5 exposure was observed at lag04 (4-month average). At lag04, every 10 μg/m3 increase in PM2.5 concentration was significantly associated with 0.33, 0.29, 0.35, 0.16, 0.04, 0.64, and 1.66 ng/g hair increases in Acy, Ace, Flu, Ant, Chr, BaP, and total PAHs, respectively (P < 0.05). The findings underscore the significant contribution of ambient PM2.5 exposure to the elevation of PAHs in human hair. Specifically, each centimeter of hair represents a one-month exposure to ambient PM2.5. Moreover, the accumulation of BaP, a carcinogenic PAH, significantly increased at heightened PM2.5 levels, emphasizing the importance of hair analysis in assessing PAH exposure risks and obtaining reliable and comprehensive health risk information. Keywords: Polycyclic aromatic hydrocarbons, Hair analysis, PM2.5