Wildfire Smoke Days Rise at U.S. Schools

A new study finds school and childcare smoke days have climbed sharply since 2006, with some buildings showing higher indoor fine-particle levels than outdoor air.

Updated on Nov. 3, 2026 in Asthma

Bold flat-color editorial illustration of a low-rise school building softened by brownish-grey smoke haze under a faint orange sun, conveying wildfire smoke affecting children's indoor air. — Average school days with wildfire smoke in the air rose from about seven a year in 2006 to 54 in 2023, and some West Coast classrooms had indoor particle levels above outdoor air. AI Illustration. Upload story photo >

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Do you trust your local schools to keep children safe from wildfire smoke?

Average school days with wildfire smoke in the surrounding air rose from about seven a year in 2006 to 54 in 2023, according to a new study. Average childcare center smoke days climbed from about nine to 112 over the same period.

Why it matters

Fine particles in wildfire smoke, known as PM2.5, can penetrate deep into the lungs and affect children with respiratory conditions. The findings suggest indoor air at some facilities may not offer protection from smoke that is present outside.

The analysis drew on air quality records from more than 100,000 schools and 130,000 childcare centers nationwide, and the broader indoor comparison covered 71 West Coast facilities. The indoor-outdoor comparison is limited to that West Coast sample, and the extraction does not indicate how widely the indoor findings apply across the country.

The players

Environmental Research

An academic journal publishing peer-reviewed research on environmental health and pollution science.

The details

Researchers compared indoor and outdoor air quality at 71 West Coast schools and childcare centers and found that some facilities had higher indoor PM2.5 concentrations than nearby outdoor measurements during smoke days. The study is published in the Dec. 1 issue of the journal Environmental Research.

2006: Baseline year, when schools averaged about seven smoke days per year.
2023: Schools averaged 54 smoke days and childcare centers averaged 112.
Dec. 1: Study appears in the Environmental Research issue.

Big Picture

The rising number of smoke days documented in U.S. wildfire records now extends into the classrooms and childcare centers where children spend much of their time. The study shows that exposure to outdoor smoke is becoming a recurring feature of the school year rather than an occasional event.

Families of children with asthma or other respiratory conditions may want to ask schools and childcare centers how they monitor air quality on smoke days. Knowing how often smoke reaches school grounds can help parents plan for indoor air protection.

The takeaway

Smoke days at schools are no longer rare, so parents and staff should consider how indoor air is managed during wildfire season. Asking facilities about air filtration and monitoring can be a practical first step for protecting children.