A report from the Oregon Health Authority is raising alarms about the long-term trajectory of wildfire smoke exposure for Oregon residents — and the findings are particularly striking for people living in the state's most populous urban centers.

The Oregon Health Authority's Climate and Health in Oregon 2025 report, with updated findings released this week, documents a clear upward trend: there are now more days of extreme heat and wildfire smoke than there were 20 years ago, and sometimes both occur simultaneously — compounding the health risk for vulnerable populations who have limited ability to escape either hazard.

Urban Areas Seeing the Fastest Growth in Smoke Exposure

Perhaps the most striking finding involves the geographic distribution of the worsening trend. While rural communities near fire-prone forests have historically borne the brunt of wildfire smoke, the report finds that the amount of wildfire-related particulate matter in the air is now rising more quickly in heavily populated areas — including the Portland metro spanning Multnomah and Washington counties — than in other parts of the state.

This counterintuitive finding reflects the long-range transport of wildfire smoke: plumes from large fires in eastern Oregon, eastern Washington, California, and even British Columbia routinely travel hundreds of miles to blanket western Oregon's population centers during summer and early fall, exposing millions of residents to elevated PM2.5 levels regardless of how far they live from any active fire.

Health Risks of Wildfire Smoke

Wildfire smoke is a complex mix of fine particulate matter (PM2.5), carbon monoxide, volatile organic compounds, and hundreds of toxic and carcinogenic chemicals. Health impacts include:

  • Short-term: Respiratory irritation, asthma attacks, eye and throat irritation, headaches, cardiovascular stress
  • Long-term: Reduced lung function, chronic respiratory disease, increased cardiovascular disease risk — particularly with repeated seasonal exposures over years
  • Vulnerable populations: Children, the elderly, pregnant individuals, people with pre-existing respiratory or heart conditions, and outdoor workers face elevated risk even at moderate AQI levels

What Oregonians Can Do to Protect Themselves

  • Monitor AirNow.gov or the Oregon DEQ's interactive air quality map throughout fire season and during prescribed burn activity.
  • Invest in home air filtration: HVAC systems with MERV-13 or better filters, or portable HEPA air purifiers in living spaces.
  • Keep N95 respirators on hand and learn to wear them correctly — a cloth mask does not filter PM2.5.
  • Limit outdoor activity when the Air Quality Index (AQI) exceeds 100 (Unhealthy for Sensitive Groups) or 150 (Unhealthy for All).
  • Create a "clean air room" during smoke events by sealing gaps around doors and windows and running an air purifier continuously.
  • Know where your nearest public clean air shelter is — many Oregon counties maintain these facilities for residents without access to home filtration.

The Prescribed Fire Connection

The OHA report also touches on a key wildfire management tension. Prescribed burns — which intentionally produce smoke — are one of the most effective tools available for reducing future wildfire risk. However, that smoke does temporarily affect local air quality. Fire and health officials emphasize that the short-term smoke exposure from a well-managed prescribed burn is typically far less significant than the prolonged, dense smoke events produced by the uncontrolled wildfires those burns help prevent. Getting ahead of the problem through prescribed fire, the science increasingly suggests, is also a public health intervention — not just a land management one.