The impact of short-term exposures to ambient NO₂, O₃, and their combined oxidative potential on daily mortality

It is widely recognized that air pollution exerts substantial detrimental effects in human health and the economy. The potential for harm is closely linked to the concentrations of pollutants like nitrogen dioxide (NO₂) and ozone (O₃), as well as their collective oxidative potential (O_X). Yet, due to the challenges of directly monitoring O_X as an independent factor and the influences of different substances' varying ability to contain or convey O_X, uncertainties persist regarding its actual impact. To provide further evidence to the association between short-term exposures to NO₂, O₃, and O_X and mortality, this study conducted multi-county time-series analyses with over-dispersed generalized additive models and random-effects meta-analyses to estimate the mortality data from 2014 to 2020 in Jiangsu, China. The findings reveal that short-term exposures to these pollutants are linked to increased risks of all-cause, cardiovascular, and respiratory mortality, where NO₂ demonstrates 2.11% (95% confidence interval: 1.79%, 2.42%), 2.28% (1.91%, 2.66%), and 2.91% (2.13%, 3.69%) respectively per every 10 ppb increase in concentration, and the effect of O₃ is 1.11% (0.98%, 1.24%), 1.39% (1.19%, 1.59%), and 1.82% (1.39%, 2.26%), and O_X is 1.77% (1.58%, 1.97%), 2.19% (1.90%, 2.48%), and 2.90% (2.29%, 3.52%). Notably, women and individuals aged over 75 years exhibit higher susceptibility to these pollutants, with NO₂ showing a greater impact, especially during the warm seasons. The elevated mortality rates associated with NO₂, O₃, and O_X underscore the significance of addressing air pollution as a pressing public health issue, especially in controlling NO₂ and O₃ together. Further research is needed to explore the underlying mechanisms and possible influential factors of these effects.