Inter-continental variability in the relationship of oxidative potential and cytotoxicity with PM2.5 mass
Sudheer Salana, Haoran Yu, Zhuying Dai, P. S. Ganesh Subramanian, Joseph V. Puthussery, Yixiang Wang, Ajit Singh, Francis D. Pope, Manuel A. Leiva G., Neeraj Rastogi, S. N. Tripathi, Rodney J. Weber, Vishal Verma
Abstract
Abstract Most fine ambient particulate matter (PM 2.5 )-based epidemiological models use globalized concentration-response (CR) functions assuming that the toxicity of PM 2.5 is solely mass-dependent without considering its chemical composition. Although oxidative potential (OP) has emerged as an alternate metric of PM 2.5 toxicity, the association between PM 2.5 mass and OP on a large spatial extent has not been investigated. In this study, we evaluate this relationship using 385 PM 2.5 samples collected from 14 different sites across 4 different continents and using 5 different OP (and cytotoxicity) endpoints. Our results show that the relationship between PM 2.5 mass vs. OP (and cytotoxicity) is largely non-linear due to significant differences in the intrinsic toxicity, resulting from a spatially heterogeneous chemical composition of PM 2.5 . These results emphasize the need to develop localized CR functions incorporating other measures of PM 2.5 properties (e.g., OP) to better predict the PM 2.5 -attributed health burdens.