Wintertime air pollution and health risk assessment of inhalation exposure to polycyclic aromatic hydrocarbons in rural China

Household air pollution is one important environmental risk to human health in China, however, rural air pollution is often underappreciated and field measurements are limited compared to studies in urban area. The present study investigated indoor and outdoor polycyclic aromatic hydrocarbons (PAHs), and population inhalation exposure from two rural counties in Shanxi and Guizhou provinces, respectively. The indoor levels were higher than the corresponding outdoor concentration in both sites, which was mainly affected by the indoor fuel combustion emissions. A majority of particulate PAHs was found in submicron PM_1.0. Fuel types had significant impacts on the total PAHs mass concentration but also composition profiles. In homes using electricity, the PAHs concentration was lower than those burning solid fuels, and there were relatively more fractions of low molecular weight PAHs with 2–3 rings, while for those burning solid fuels, higher fractions of high molecular weight PAHs with 5–6 rings may pose larger adverse health impacts. Although the daily inhalation exposure level for the population using electricity was much lower than those using solid fuels, the estimated Incremental Lifetime Cancer Risk still exceeded the deemed safe risk of 10⁻⁶. Inhalation exposure amounts measured by using portable carried samplers were compared to the estimation based on area concentration. The substantial discrepancy between them confirmed a preferable use of portable carried samplers in exposure evaluation and health risk assessment.