Wildfire Smoke Raises Asthma Risks as Fires Worsen Air Quality Across North America

Escalating wildfire smoke from fires burning across eastern Washington, eastern Oregon, and Idaho, as well as Canada, is worsening air quality across certain parts of the US, resulting in public health organizations publishing emergency procedures and actions, especially for those struggling with asthma.¹

Wildfire smoke is becoming a global health problem as global temperatures continue to rise, creating drier climates that have resulted in more frequent and severe wildfires.² The current surge of wildfires in eastern Washington, Oregon, and Idaho has been fueled by tinder-dry conditions and extreme heat, with lightning from recent monsoon thunderstorm that recently moved across the Pacific Northwest sparking many of the blazes, according to AccuWeather. These wildfires pose harmful conditions, as the thick smoke emanating from the source is “significantly degrading” air quality and blocking visibility across the Northern US.¹

How Wildfire Smoke Increases Asthma Risks

“There’s a very strong case to be made for these fires having a serious impact on those with asthma,” Christopher Carlsten, MD, director of the Centre for Lung Health, said in a 2024 webinar outlining the risks of poor air quality caused by the wildfire for individuals with asthma.

During the webinar, he and Emily Brigham, MD, assistant professor of respiratory medicine at the University of British Columbia, emphasized that the increased exposure to fine particle matter (PM_2.5) is associated with increased rescue inhaler use, physician visits for asthma, emergency care, and, at the population level, increases in mortality during major smoke events.³

They also said wildfires are increasing the pollution-related health effects researchers expect to see in the coming decade.³

“This fire problem is predicted to become not only worse but also a much bigger part of the total problem that we're dealing with,” he said during the webinar.³

More than 900 wildfires are burning in Canada, with Ontario experiencing its worst wildfire season on record, prompting public health organizations to publish notices, especially for those with asthma.^3,4

Experts Recommend Air Quality Monitoring and Asthma Preparedness

Asthma Canada cited 5 preventive action items for individuals with asthma as the wildfires continue to rage. These include staying informed by tracking the wildfires and air quality; having an updated asthma action plan; using an air purifier in your home; taking any prescribed medication as necessary; and staying hydrated.⁵

The notice also encouraged individuals to limit outdoor activities and avoid physical exertion or exercise outdoors during peak pollution periods. However, if going outside is necessary, they recommended wearing a well-fitting N95 respirator mask, keeping an inhaler on your person at all times, keeping car windows and vents closed while driving, and using the ‘recirculate’ setting when using the car’s air conditioning.³

Brigham’s sentiments on preparedness reflect many of those posted on Asthma Canada. She continued to encourage patients to consult with their physician and continually monitor air quality to help guide any medication adjustments during smoke events.⁴

“If you can see or smell smoke, your air quality risk is very high. The important thing to recognize is that if you can't see or you can't smell smoke, that does not mean there is no risk,” she said during the webinar.

References

1. Sosnowski A. Wildfire smoke spreads to Canada, East as northwestern US fires multiply. Accuweather. July 25, 2026. Accessed July 29, 2026. https://www.accuweather.com/en/weather-forecasts/wildfire-smoke-spreads-to-canada-east-as-northwestern-us-fires-multiply/1915351

2. Wildfire smoke, asthma and the immune system. American Academy of Allergy Asthma & Immunology. July 22, 2026. Accessed July 29, 2026. https://www.aaaai.org/tools-for-the-public/conditions-library/asthma/wildfire

3. Asthma Canada. Living with asthma: How air quality and wildfires affect your health. YouTube. Published February 14, 2024. Accessed July 29, 2026. https://www.youtube.com/watch?v=Qp27mdo5m9s

4. Bowden O. Canada’s worst wildfire season fuels calls for national agency to tackle threat. The Guardian. July 29, 2026. Accessed July 29, 2026. https://www.theguardian.com/world/2026/jul/29/canada-wildfire-emergency-agency

5. Wildfire season advice for people living with asthma. Asthma Canada. Accessed July 29, 2026. https://asthma.ca/wildfires/