Application of cell-based biological bioassays for health risk assessment of PM2.5 exposure in three megacities, China

The determination of PM2.5-induced biological response is essential for understanding the adverse health risk associated with PM2.5 exposure. In this study, we conducted cell-based bioassays to measure the toxic effects of PM2.5 exposure, including cytotoxicity, oxidative stress, genotoxicity and inflammatory response. The concentration-response relationship was analyzed by benchmark dose (BMD) modeling and the BMDL10 was used to estimate the biological potency of PM2.5 exposure. PM2.5 samples were collected from three typical megacities of China (Beijing, BJ; Wuhan, WH; Guangzhou, GZ) in typical seasons (winter and summer). The total PM, water-soluble fractions (WSF), and organic extracts (OE) were prepared and subjected to examination of toxic effects. The biological potencies for cytotoxicity, oxidative stress and genotoxicity were generally higher in winter samples, while the inflammatory potency of PM2.5 was higher in summer samples. The relative health risk (RHR) was determined by integration of the biological potencies and the cumulative exposure level, and the ranks of RHR were BJ-W > WH-W > BJ-S > WH-S > GZ-W > GZ-S. Notably, we note that different PM2.5 compositions were associated with distinct biological effects, and the health effects distribution of PM2.5 varied in regions and seasons. These findings demonstrate that the approach of integrated cell-based bioassays could be used for the evaluation of health effects of PM2.5 exposure.