Higher Risk of Cardiovascular Disease Associated with Smaller Size-Fractioned Particulate Matter

No nationwide studies have examined the associations between mortality risk and PM1 (PM with an aerodynamic diameter of <1 mu m) due to the scarcity of monitoring data of PM1. On the basis of newly released national scale PM1 data, we performed a time series analysis to elucidate the cause-specific mortality risk caused by PM1 exposure in China. During the period from January 2014 to December 2017, the PM1 levels in 65 cities of China were on average 37 +/- 32 mu g/m(3). Pooled results indicated a 10 mu g/m(3) increase in the PM1 level was associated with a 0.19% [95% confidence interval (CI) of 0.09-0.28%] increased risk in nonaccidental mortality, which was almost the same as that for PM2.5 (0.18%, 95% CI of 0.08-0.27%) and PM10 (0.17%, 95% CI of 0.01-0.24%). By comparison, the magnitude increased to 0.29% (0.12-0.47%) in cardiovascular disease for each 10 mu g/m(3) uptick in PM1, which was significantly higher than that related to PM2.5 and PM10 exposure. This nationwide study supported the notion that PM1 may be a higher risk factor for cardiovascular disease, which suggests rapid action is warranted to put more effort into mitigating the emissions of finer particulate matters.