Associations between Fine Particulate Matter Components, Their Sources, and Cognitive Outcomes in Children Ages 9-10 Years Old from the United States.

Background: Emerging literature suggests that fine particulate matter [with aerodynamic diameter $\le 2.5\mu m$ (${\mathrm{PM}}_{2.5}$)] air pollution and its components are linked to various neurodevelopmental outcomes. However, few studies have evaluated how ${\mathrm{PM}}_{2.5}$ component mixtures from distinct sources relate to cognitive outcomes in children.

Objectives: This cross-sectional study investigated how ambient concentrations of ${\mathrm{PM}}_{2.5}$ component mixtures relate to neurocognitive performance in 9- to 10-year-old children, as well as explored potential source-specific effects of these associations, across the US.

Methods: Using spatiotemporal hybrid models, annual concentrations of 15 chemical components of ${\mathrm{PM}}_{2.5}$ were estimated based on the residential address of child participants from the Adolescent Brain Cognitive Development (ABCD) Study. General cognitive ability, executive function, and learning/memory scores were derived from the NIH Toolbox. We applied positive matrix factorization to identify six major ${\mathrm{PM}}_{2.5}$ sources based on the 15 components, which included crustal, ammonium sulfate, biomass burning, traffic, ammonium nitrate, and industrial/residual fuel burning. We then utilized weighted quantile sum (WQS) and linear regression models to investigate associations between ${\mathrm{PM}}_{2.5}$ components' mixture, their potential sources, and children's cognitive scores.

Results: Mixture modeling revealed associations between cumulative exposure and worse cognitive performance across all three outcome domains, including shared overlap in detrimental effects driven by ammonium nitrates, silicon, and calcium. Using the identified six sources of exposure, source-specific negative associations were identified between ammonium nitrates and learning & memory, traffic and executive function, and crustal and industrial mixtures and general cognitive ability. Unexpected positive associations were also seen between traffic and general ability as well as biomass burning and executive function.

Discussion: This work suggests nuanced associations between outdoor ${\mathrm{PM}}_{2.5}$ exposure and childhood cognitive performance, including important differences in cognition related both to individual chemicals as well as to specific sources of these exposures. https://doi.org/10.1289/EHP14418.