Wildfire smoke exposure increases the risk of mental illness in youth: each additional day of exposure to wildfire smoke and other severe air pollution slightly raises the risk of mental illness in children aged 9 to 11

>Smolker’s study is among the first to look at potential impacts on adolescents, whose brains are still developing.
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>The team analyzed data from 10,000 pre-teens participating in the ongoing Adolescent Brain Cognitive Development (ABCD) Study—the largest long-term study of brain development and child health ever conducted in the United States. CU Boulder is one of 21 ABCD research sites.
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>They looked at participant addresses and historical air quality data to determine how many days in 2016 youth were exposed to PM2.5 levels above 35 micrograms per cubic meter (35ug/m3) – the level the Environmental Protection Agency deems unsafe.
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>About one-third were exposed to at least one day above the EPA standard. One participant was exposed to unsafe levels for 173 days. The highest level of exposure reported was 199 micrograms/m3 – more than five times the level deemed safe.
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>When looking at parent questionnaires at four time points over three years, the researchers found that, across both genders, each additional day of exposure at unsafe levels boosted the likelihood of a youth having symptoms of depression, anxiety and other “internalizing symptoms” up to one year later.
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>This was after accounting for a wide variety of potentially confounding factors, including race, neighborhood characteristics, socioeconomic status and, notably, parental mental health. Even when parents did not report symptoms themselves, they often reported higher symptoms in their children. 
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>“This suggests that PM2.5 exposure may have specific impacts on youth distinct from impacts on their parents,” Smolker said.

>**For each day of unsafe exposure, risk went up .1 points on average on a scale of 1 to 64.**

Paper: [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 | Environmental Health Perspectives | Vol. 132, No. 8](https://ehp.niehs.nih.gov/doi/10.1289/EHP13427)