San Francisco vs Seattle Air Quality Comparison
Which city has cleaner air right now, from the latest EPA AirNow AQI
As of September 16, 2026, San Francisco, CA has cleaner air than Seattle, WA — AQI 36 (Good) vs 37 (Good), a gap of 1 AQI points in the latest EPA AirNow observations. Lower AQI means cleaner air. San Francisco's reading is driven by PM2.5 and Seattle's by PM2.5.
San Francisco, CA
Good
Seattle, WA
Good
Summary
San Francisco has 1 points better air quality
San Francisco has an AQI of 36 compared to 37
Our Pick
Improve Indoor Air Quality
Even with good outdoor air in Seattle, indoor PM2.5, dust and allergens build up. A True-HEPA purifier keeps a bedroom or office consistently clean.
Budget Pick4.7(74,000+ ratings)
Levoit Core 400S
True HEPA · CADR ~141 CFM · rooms up to 219 sq ft
Best value True-HEPA for everyday allergens, dust and dander
Compare top-rated True-HEPA purifiers:
Budget Pick
Levoit Core 400S
True HEPA
True HEPA · CADR ~141 CFM · rooms up to 219 sq ft
~$1004.7
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
Check Price on Amazon →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 →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
| Day | San Francisco | Seattle | Better |
|---|---|---|---|
| Today | AQI 44 | AQI 44 | Tie |
| Wed, Sep 16 | AQI 50 | AQI 39 | Seattle |