Acute cardiovascular mortality risks from PM2.5 and its chemical components in an industrial valley city: evidence from Lanzhou, China

The relative contributions of specific fine particulate matter (PM2.5) chemical components to acute cardiovascular disease (CVD) mortality remain poorly understood, especially in industrial valley cities like Lanzhou, China. We analyzed 9 years (2015-2023) of daily CVD mortality data (n = 69,669) from Lanzhou. Generalized additive models (GAM) were used to assess acute PM2.5-CVD mortality associations. A random forest model (r>0.70) predicted daily PM2.5 component concentrations, followed by quantile g-computation (qgcomp) and weighted quantile sum (WQS) regression to identify key toxic components. PM2.5 was significantly associated with CVD mortality at lag 0 (excess risk = 2.06% per 10μg/m³, 95% CI: 0.66-3.48%), with stronger effects in males and adults <65 years. Regional heterogeneity emerged: in traffic-dominated Chengguan, PAHs (phenanthrene, anthracene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene) and metals (thallium, lead, manganese) were primary contributors; in industrial Xigu, ions (nitrate, chloride, sulfate) and PAHs (benzo[a]anthracene, indeno[1,2,3-cd] pyrene) drove risks, with no significant metal effects. Our findings reveal that PM2.5 has acute effects on cardiovascular health in Lanzhou. The health risks from PM2.5 components vary across different areas of the city. This highlights the need to develop targeted air pollution control strategies that address specific local emission sources in industrial valley cities.