Limited is known about how the components of particulate matter with aerodynamic diameter < 2.5 μm (PM2.5) are related to congenital heart disease (CHD). We aimed to demonstrate the relationship between exposure to PM2.5 components during early pregnancy and the risk of CHD. This study included 2,601,300 live births and stillbirths in Guangdong, China from 2014 to 2017. Satellite remote sensing data of PM2.5 components were collected, including organic matter (OM), sulfate (\({\text{S}\text{O}}_{4}^{2-}\)), nitrate (\({\text{N}\text{O}}_{3}^{-}\)), ammonium (\({\text{N}\text{H}}_{4}^{+}\)), and black carbon (BC). Unconditional logistic regression models were constructed to estimate the relationship of each PM2.5 component to CHD. The quantile g-computation method was used to evaluate the contribution weight of each PM2.5 component in relation to CHD in the exposure mixture. The estimated effect size of each PM2.5 component peaked in the first week of pregnancy. Among them, \({\text{S}\text{O}}_{4}^{2-}\) exhibited the strongest estimated effect (OR: 2.23, 95% CI 2.19–2.27), followed by BC (OR: 1.95, 95% CI 1.91–1.98). The joint exposure analysis revealed that the estimated weights of \({\text{S}\text{O}}_{4}^{2-}\) and BC were 86.78% and 13.22%, respectively. These findings suggest that exposure to PM2.5 components during early pregnancy increases the risk of CHD in the offspring, and \({\text{S}\text{O}}_{4}^{2-}\) may be the primary PM2.5 component responsible for this elevated risk.
