San Francisco vs San Diego Air Quality Comparison
Which city has cleaner air right now, from the latest EPA AirNow AQI
As of November 14, 2026, San Francisco, CA has cleaner air than San Diego, CA — AQI 12 (Good) vs 41 (Good), a gap of 29 AQI points in the latest EPA AirNow observations. Lower AQI means cleaner air. San Francisco's reading is driven by PM2.5 and San Diego's by O3.
San Francisco, CA
Good
San Diego, CA
Good
Summary
San Francisco has 29 points better air quality
San Francisco has an AQI of 12 compared to 41
Reduce Indoor Ozone in San Diego
Today's main pollutant in San Diego is ground-level ozone (AQI 41). 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):
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 | San Diego | Better |
|---|---|---|---|
| Today | AQI 64 | AQI 42 | San Diego |
| Wed, Nov 11 | AQI 66 | AQI 44 | San Diego |