The Association between Exposure to Fine Particulate Air Pollution and the Trajectory of Internalizing and Externalizing Behaviors during Late Childhood and Early Adolescence: Evidence from the Adolescent Brain Cognitive Development (ABCD) Study.

Background: Exposure to high levels of fine particulate matter (PM) with aerodynamic diameter $\le 2.5\mu m$ (${\mathrm{PM}}_{2.5}$) via air pollution may be a risk factor for psychiatric disorders during adulthood. Yet few studies have examined associations between exposure and the trajectory of symptoms across late childhood and early adolescence.

Objective: The current study evaluated whether ${\mathrm{PM}}_{2.5}$ exposure at 9-11 y of age affects both concurrent symptoms as well as the longitudinal trajectory of internalizing and externalizing behaviors across the following 3 y. This issue was examined using multiple measures of exposure and separate measures of symptoms of internalizing disorders (e.g., depression, anxiety) and externalizing disorders (e.g., conduct disorder), respectively.

Methods: In a sample of more than 10,000 youth from the Adolescent Brain Cognitive Development (ABCD) Study, we used a dataset of historical ${\mathrm{PM}}_{2.5}$ levels and growth curve modeling to evaluate associations of ${\mathrm{PM}}_{2.5}$ exposure with internalizing and externalizing symptom trajectories, as assessed by the Child Behavioral Check List. Three distinct measures of ${\mathrm{PM}}_{2.5}$ exposure were investigated: annual average concentration during 2016, number of days in 2016 above the US Environmental Protection Agency (US EPA) 24-h ${\mathrm{PM}}_{2.5}$ standards, and maximum 24-h concentration during 2016.

Results: At baseline, higher number of days with ${\mathrm{PM}}_{2.5}$ levels above US EPA standards was associated with higher parent-reported internalizing symptoms in the same year. This association remained significant up to a year following exposure and after controlling for ${\mathrm{PM}}_{2.5}$ annual average, maximum 24-h level, and informant psychopathology. There was also evidence of an association between ${\mathrm{PM}}_{2.5}$ annual average and externalizing symptom levels at baseline in females only.

Discussion: Results suggested ${\mathrm{PM}}_{2.5}$ exposure during childhood is associated with higher symptoms of internalizing and externalizing disorders at the time of exposure and 1 y later. In addition, effects of ${\mathrm{PM}}_{2.5}$ exposure on youth internalizing symptoms may be most impacted by the number of days of exposure above US EPA standards in comparison with annual average and maximum daily exposure. https://doi.org/10.1289/EHP13427.