Long-term exposure to PM2.5 components and mortality in 237 Chinese cities: a modelling study

Evidence on the lagged effects of long-term exposure to fine particulate matter (PM2.5) components is limited. Data on air pollution, meteorology, population health and socioeconomic status were collected from 237 major cities in China between 2015 and 2019. The differences-in-differences model was established to analyze the lagged effects of the annual mean concentration of PM2.5 components on mortality. The PM2.5 component-mortality associations exhibited long-term lag patterns, with statistically significantly at lag 2 and lag 3 yr. During the cumulative lags of 0-3 yr, each interquartile range increase in exposure to EC, OC, SO42-, NO3-, and NH4+, total mortality risk increased by 9% (RR=1.09; 95%CI: 1.02, 1.16), 8% (RR=1.08; 95%CI: 1.01, 1.15), 16% (RR=1.16; 95%CI: 1.07, 1.25), 22% (RR=1.22; 95%CI: 1.08, 1.38), and 16% (RR=1.16; 95%CI: 1.04, 1.29), respectively. Additionally, the observed associations between PM2.5 components and mortality risks were much stronger among the high-longitude (eastern) regions, as well as areas with high air pressure and high GDP per capita. These findings may help provide critical implication for formulating a multi-domain cooperative control strategies on PM2.5 components.