Associations of prenatal exposure to PM2.5 and its components with offsprings' neurodevelopmental and behavioral problems: A prospective cohort study from China

Prenatal exposure to fine particulate matter (PM_2.5) has been linked with increased neurodevelopmental disorders. However, the most detrimental component of PM_2.5 and the most vulnerable exposure time windows remain undetermined, especially in areas with high PM_2.5 levels. In a prospective cohort study involving 4494 mother-child dyads, we examined the associations of prenatal exposure to PM_2.5 and its four main components with children's neurodevelopmental and behavioral problems (NBPs), separately in three pregnancy trimesters. Poisson regression and generalized additive models were used to depict the linear and nonlinear associations, respectively. Weighted quantile sum and Bayesian kernel machine regression models were applied to examine the effects of exposure to both mixed and individual components. Results showed that exposure to PM_2.5 and its components throughout the three trimesters increased the risk of children's NBPs (Risk ratio for PM_2.5: 1.16, 95 % confidence interval 1.14-1.18 per μg/m³ in the first trimester; 1.15, 1.12-1.17 in the second trimester; 1.06, 1.04-1.08 in the third trimester), with associations gradually diminishing as pregnancy progressed (P values for trends < 0.05). Among the four main components of PM_2.5, exposure to SO₄^2- posed the highest risks on children's NBPs, while organic matter contributed the largest proportion to the overall impacts of PM_2.5 exposure. These results underscore the significance of mitigating PM_2.5 exposure in pregnant women to reduce the risk of neurodevelopmental disorders in offspring. Our findings would inform risk assessment of PM_2.5 exposure and facilitate the development of precision preventive strategies targeting specific components of PM_2.5 in similar areas with high levels of exposure.