The impact of short-term exposures to PM2.5 components and the modification effects of ozone on daily mortality

The health impacts of PM_2.5 components, namely Sulfate, Nitrate, Ammonium, Organic Matter, and Black Carbon, on daily mortality warrant further investigation, especially on the interaction with Ozone due to the significant health impacts and interactivity of them. To investigate the associations between short-term exposure to PM_2.5 and its main components on daily all-cause, cardiovascular, and respiratory mortality, as well as the influence of ozone, we conducted a multi-city, time-series analysis involving 3,438,346 mortality records in Jiangsu, China. Over-dispersed generalized additive models and random-effects meta-analyses were applied to estimate the effect sizes, followed by stratified analyses and estimates of the interaction with ozone. Our findings indicate that PM_2.5 and its components are significantly associated with increased daily mortality. Specifically, every interquartile range increase in PM_2.5 resulted in a 1.97 % increase in all-cause mortality, 2.15 % increase in cardiovascular mortality, and 2.34 % increase in respiratory mortality. Similar but less significant effects were found in five PM_2.5 components. Women and the elderly were more susceptible, and the effects were stronger during warm seasons for all pollutants except Sulfate. High levels of ozone amplified the mortality risks associated with PM_2.5, Sulfate, Nitrate, and Ammonium, but not with Organic Matter and Black Carbon. These findings underscored the need for integrated air quality management strategies to mitigate the adverse health impacts of these pollutants.