Increased mortality risk from airborne exposure to polycyclic aromatic hydrocarbons

The potential health effects of airborne polycyclic aromatic hydrocarbons (PAHs) among general population remained extensively unstudied. This study sought to investigate the association of short-term exposure to low-level total and 7 carcinogenic PAHs with mortality risk. We conducted an individual-level time-stratified case-crossover study in Jiangsu province of eastern China, by investigating over 2 million death cases during 2016–2019. Daily concentrations of total PAH and its 7 carcinogenic species including benzo[a]anthracene (BaA), benzo[a]pyrene (BaP), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), chrysene (Chr), dibenz[a,h]anthracene (DahA), and indeno[1,2,3-cd]pyrene (IcdP), predicted by well-validated spatiotemporal models, were assigned to death cases according to their residential addresses. We estimated mortality risk associated with short-term exposure to increase of an interquartile range (IQR) for aforementioned PAHs using conditional logistic regression. An IQR increase (16.9 ng/m3) in 2-day (the current and prior day) moving average of total PAH concentration was associated with risk increases of 1.90% (95% confidence interval [CI]: 1.71–2.09) in all-cause mortality, 1.90% (95% CI: 1.70–2.10) in nonaccidental mortality, 2.01% (95% CI: 1.72–2.29) in circulatory mortality, and 2.53% (95% CI: 2.03–3.02) in respiratory mortality. Risk increases of cause-specific mortality ranged between 1.42–1.90% for BaA (IQR: 1.6 ng/m3), 1.94–2.53% for BaP (IQR: 1.6 ng/m3), 2.45–3.16% for BbF (IQR: 2.8 ng/m3), 2.80–3.65% for BkF (IQR: 1.0 ng/m3), 1.36–1.77% for Chr (IQR: 1.8 ng/m3), 0.77–1.24% for DahA (IQR: 0.8 ng/m3), and 2.96–3.85% for IcdP (IQR: 1.7 ng/m3). This study provided suggested evidence for heightened mortality risk in relation to short-term exposure to airborne PAHs in general population. Our findings suggest that airborne PAHs may pose a potential threat to public health, emphasizing the need of more population-based evidence to enhance the understanding of health risk under the low-dose exposure scenario.