Within- and between-study site variations in ambient air pollution exposure at ages 9-10 years in the Adolescent Brain Cognitive Development (ABCD) Study

Minority and socioeconomically disadvantaged populations are disproportionately exposed to elevated levels of air pollution. This environmental injustice exhibits distinct patterns and predictors across regions of the United States, which we investigate by leveraging baseline data (2016-2018) from the Adolescent Brain Cognitive Development (ABCD) Study, the largest longitudinal study of child brain development in the United States. Specifically, we examine within- and between-site variability in exposure to fine particulate matter (PM2.5) and nitrogen dioxide (NO2) among 9- to 10-year-old participants. Using geocoded residential addresses and hybrid spatiotemporal models, air pollution exposure disparities were estimated by site, and by family- and neighborhood-level socioeconomic metrics within each site. Results indicate substantial variation in race/ethnicity- and class-based gaps in air pollution exposure across the 21 ABCD study sites. Overall, Hispanic/Latinx and Black children experienced higher average levels of PM2.5 and NO2 compared to their white counterparts, while children in neighborhoods with lower socioeconomic status exhibited elevated exposure regardless of race or ethnicity. Within-site disparities highlighted local environmental injustices, as well, with notable differences in pollution levels across neighborhoods at different levels of disadvantage. Elevated air pollution exposure in minoritized communities aligns with well-documented systemic inequities in built environment conditions and institutional resources, exacerbating health disparities. This study highlights the importance of integrating environmental justice into public health and policy initiatives, leveraging the multisite design of the ABCD Study to provide insights for promoting health equity in child and adolescent development within and across regions in the United States.