Portland vs Seattle Air Quality Comparison

Which city has cleaner air right now, from the latest EPA AirNow AQI

As of September 23, 2026, Seattle, WA has cleaner air than Portland, OR — AQI 34 (Good) vs 52 (Moderate), a gap of 18 AQI points in the latest EPA AirNow observations. Lower AQI means cleaner air. Portland's reading is driven by PM2.5 and Seattle's by PM2.5.

Portland, OR

Moderate

StateOregon
Dominant PollutantPM2.5
CategoryModerate
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Seattle, WA

Good

StateWashington
Dominant PollutantPM2.5
CategoryGood
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Summary

Seattle has 18 points better air quality

Seattle has an AQI of 34 compared to 52

Our Pick

Extra Protection for Portland Homes

Air quality in Portland is moderate (AQI 52), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.

Large Room4.6(8,000+ ratings)
Coway AP-1512HH Mighty
True HEPA + carbon · CADR ~246 CFM · rooms up to 361 sq ft
True HEPA + carbon, high CADR — clears PM2.5 from most rooms fast, our all-round pick
~$230
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Compare top-rated True-HEPA purifiers:

Large Room
Coway AP-1512HH Mighty
HEPA + Carbon
True HEPA + carbon · CADR ~246 CFM · rooms up to 361 sq ft
~$2304.6
Check Price on Amazon →
Editor's Pick
Levoit Vital 200S
True HEPA
True HEPA · washable pre-filter · rooms up to 1,875 sq ft
~$2004.6
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Budget Pick
Levoit Core 400S
True HEPA
True HEPA · CADR ~141 CFM · rooms up to 219 sq ft
~$1004.7
Check Price on Amazon →

Prices are approximate and subject to change. As an Amazon Associate, we earn from qualifying purchases at no extra cost to you.

5-Day Forecast Comparison

DayPortlandSeattleBetter
TodayAQI 50AQI 39Seattle

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