Portland vs Seattle Air Quality Comparison
Which city has cleaner air right now, from the latest EPA AirNow AQI
As of November 14, 2026, Seattle, WA has cleaner air than Portland, OR — AQI 26 (Good) vs 30 (Good), a gap of 4 AQI points in the latest EPA AirNow observations. Lower AQI means cleaner air. Portland's reading is driven by O3 and Seattle's by PM2.5.
Portland, OR
Good
Seattle, WA
Good
Summary
Seattle has 4 points better air quality
Seattle has an AQI of 26 compared to 30
Reduce Indoor Ozone in Portland
Today's main pollutant in Portland is ground-level ozone (AQI 30). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Compare activated-carbon purifiers (for gases & ozone):
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5-Day Forecast Comparison
| Day | Portland | Seattle | Better |
|---|---|---|---|
| Today | AQI 50 | AQI 28 | Seattle |