Risk of PM_2.5 and its constituents for cardiovascular diseases: A cohort study of over 5.8 million participants

Fine particulate matter (PM₂.₅) exposure has been associated with increased cardiovascular disease (CVD) risk, but data from Northwest China are limited. We conducted a longitudinal cohort study with 5,838,833 participants enrolled between 2019 and 2021. Region-specific Cox models assessed long-term PM₂.₅ exposure and CVD incidence. A 1 μg/m³ increase in PM₂.₅ was associated with a 0.5% higher CVD risk (hazard ratio [HR]: 1.005; 95% confidence interval [CI]: 1.005-1.006). Moderate and high exposure levels corresponded to HRs of 1.280 (95% CI: 1.255-1.306) and 1.373 (95% CI: 1.340-1.406). Stronger associations were observed for cerebrovascular disease (HR: 1.009; 95% CI: 1.006-1.011) than for ischemic heart disease. Among PM₂.₅ components, black carbon (BC), sulfate (SO₄ ^2-), and organic matter (OM) were significantly associated with CVD risk, with BC showing the strongest effect (HR: 1.068; 95% CI: 1.056-1.080). Our findings indicate that long-term PM₂.₅ exposure in Northwest China is associated with CVD risk, particularly cerebrovascular disease, with BC being a key contributor.