Wildfire Smoke Reverses Progress on U.S. Ozone Levels

Wildfire smoke is increasing ozone in many areas, which may affect health outcomes for those with respiratory conditions.

Updated on Oct. 23, 2026 in Asthma

Bold flat-color editorial illustration featuring stacked, geometric forest silhouettes against a hazy smog layer, representing environmental air quality decline. — A University of Iowa study found that wildfire smoke is reversing decades of progress in reducing U.S. ground-level ozone pollution. AI Illustration. Upload story photo >

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Should the federal government enact stricter air quality regulations to address rising wildfire smoke pollution?

A University of Iowa study published on 4 June 2026 reports that wildfire smoke is reversing U.S. progress on air quality. This trend affects the 43 million people exposed to hazardous ozone levels between 2022 and 2024.

Why it matters

Rising wildfire frequency driven by climate change is counteracting decades of improvements in ground-level ozone reduction. This shift threatens respiratory health for millions across the United States as pollution patterns evolve.

The University of Iowa study analyzed data from 1,200 U.S. monitoring stations to track ozone and PM2.5 trends from 2006 to 2023. While specific air quality declines were noted since 2015, the long-term human health impacts are still being mapped through ongoing atmospheric modeling.

The players

University of Iowa

A public research institution that conducted the study on wildfire smoke and air quality.

The details

Wildfire smoke introduces nitrogen oxides and volatile organic compounds into the atmosphere, which react with sunlight to form ground-level ozone. Artificial intelligence models indicate that as wildfire-burned areas have quadrupled over thirty years, these chemical reactions have effectively eroded earlier air quality gains. Increased fuel aridity and human expansion into forested zones further accelerate this cycle of pollutant production.

2000s: Ozone and PM2.5 levels declined across the United States.
2015: Ozone and PM2.5 levels began to rise.
2006-2023: Study period for average smoke ozone impact.
2022-2024: 43 million people exposed to hazardous ozone.
4 June 2026: University of Iowa study published.

Health Landscape

This study highlights a major reversal in the decades-long success of air quality policy. It suggests that climate-driven wildfire patterns are now a dominant force in population-level respiratory risk, complicating standard clean-air benchmarks.

If you live in an area prone to wildfire smoke, track your local air quality index and limit outdoor exertion during periods of high ozone. Discuss specific protection strategies, such as the use of high-efficiency indoor air filters, with your physician.

The takeaway

Wildfire smoke can significantly increase local ozone levels, creating an ongoing risk for those with respiratory conditions. Monitor daily air quality reports and consult your doctor about creating an emergency plan for managing symptoms during poor air quality events.