Is the air quality good in Portland?
As of August 5, 2026, at 8:30 AM (local time), air quality in Portland, Oregon, is poor, with an AQI of 159, which falls within the "unhealthy" range.
These conditions can affect everyone, with children, older adults, pregnant people, and those with respiratory or cardiovascular conditions facing greater risks.
Air quality is dynamic and, like the weather, can change frequently. Portland is ranked as the most polluted major city in the world on Wednesday morning.
Click here for a real-time air quality map of Portland.
While the air quality conditions today are poor, it is important to note that the average PM2.5 concentration in 2025 for Portland was 6 µg/m³. This corresponds to an AQI of 25, which falls into the “good” category and was 1.2 times the WHO annual guideline of 5 µg/m³.
Portland, Oregon, ranked as the most polluted major city on August 5, 2026, 8:30 AM (local time). Source: IQAir.
When will air quality improve in Portland?
Air quality is forecast to remain poor through tomorrow, with only minor improvement expected.
Hourly air quality forecast for Portland, Oregon, on August 5, 2026. Source: IQAir.
The Oregon Department of Environmental Quality air quality advisory has no fixed end date and remains in effect until further notice, so residents should continue monitoring local conditions and reduce outdoor exposure until levels drop.
Air quality map of Portland, Oregon, on August 5, 2026. Source: IQAir.
What is causing poor air quality in Portland?
Portland's poor air quality is caused by a record wildfire season upwind, a reversal in wind direction, and a heat pattern that traps smoke near the ground (1).
Offshore easterly flow is carrying smoke from fires in eastern Oregon and central Washington across the Cascades and into the Willamette Valley. Approximately 2,014,481 acres had burned across the Pacific Northwest and Oregon has now surpassed 2 million acres burned in a single year for the first time on record (2).
The closest and most significant source for the metro area is the Grasshopper Fire, which has burned roughly 34,000 acres around Mount Hood and has moved into Clackamas County. (3) Portland and Vancouver, Washington have been hit hardest by smoke from this fire (4).
Heat and stagnation are compounding the event. High pressure bringing near triple-digit temperatures is producing light winds and stagnant air, and Portland's position between the Coast Range and the Cascade Mountains allows the pattern to act like a lid that holds smoke close to the surface for days (5).
Heat advisories overlapping the air quality advisory also limit the option of opening windows at night to cool homes (6).
The scale of the event is reflected in the air quality advisory itself, which stretches across nearly all of Oregon and extends north into southwest Washington (7).
How can I protect myself from poor air quality?
- Get a free air quality app for real-time air quality alerts and forecasts.
- Shut doors and windows and set the HVAC to recirculate mode.
- Contribute to your community’s outdoor air quality data.
- Stay indoors when air quality is poor; if you do need to go outdoors, wear a KN95/FFP2 mask.
- Run a high-performance air purifier to filter particles, gases, and other pollutants.
