Air Pollution Exposures and Executive Function in Middle Childhood: A U.S. Multi-Cohort Study

Background and Aims: Prior studies examining the association between spatiotemporally resolved air pollution and child executive function (working memory, inhibitory control, and cognitive flexibility) are limited. We aimed to fill this gap using data from the ECHO-PATHWAYS Consortium. Methods: We included 1,241 children from three U.S. pregnancy cohorts (CANDLE, TIDES, and GAPPS). Exposure to particulate matter ≤2.5μm in aerodynamic diameter (PM₂.₅), nitrogen dioxide (NO₂), and ozone (O₃) at age 0-4 were derived from spatiotemporal models. At age 8-9, child working memory and inhibitory control were assessed using the Digit Span subtest from the Wechsler Intelligence Scale for Children, 5th Edition and the NIH Toolbox Flanker Inhibitory Control and Attention test, respectively. Cognitive flexibility was quantified by percent accuracy and mean latency of the Hearts and Flowers Task mixed block condition. We fitted linear regression models adjusted for sociodemographic, behavioral, and maternal psychological factors, and examined potential modification by child sex, maternal education, and neighborhood education quality. Results: Mean PM₂.₅, NO₂, and O₃ were 8.9 (SD:1.7) µg/m³, 9.2 (SD:2.8) ppb, and 25.7 (SD:2.8) ppb, respectively. Overall, each 2-ppb increase of NO₂ was associated with a 1.1% lower percent accuracy in cognitive flexibility (95%CI: -1.8%, -0.3%), whereas other associations were all null. We found sex-specific inverse associations of NO₂ with working memory (Pinteraction: 0.019) and cognitive flexibility (Pinteraction: 0.017), and between PM₂.₅ and inhibitory control (Pinteraction: 0.022), only in boys. The positive association between PM₂.₅ and mean latency was stronger in children whose mothers completed high school or less (Pinteraction: 0.045). The protective association between PM₂.₅ and cognitive flexibility was shown exclusively in children residing in neighborhoods with better education quality (Pinteraction: 0.004). Conclusions: Our study contributes to a nascent literature on common air pollution exposures, notably NO₂, and child executive function. Keywords: Air pollution exposures, executive functions, child health