Los Angeles vs San Francisco 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 Los Angeles, CA — AQI 36 (Good) vs 38 (Good), a gap of 2 AQI points in the latest EPA AirNow observations. Lower AQI means cleaner air. Los Angeles's reading is driven by O3 and San Francisco's by PM2.5.
Los Angeles, CA
Good
San Francisco, CA
Good
Summary
San Francisco has 2 points better air quality
San Francisco has an AQI of 36 compared to 38
Reduce Indoor Ozone in Los Angeles
Today's main pollutant in Los Angeles is ground-level ozone (AQI 38). 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 | Los Angeles | San Francisco | Better |
|---|---|---|---|
| Today | AQI 50 | AQI 44 | San Francisco |