San Diego, California vs San Francisco, California Air Quality
Side-by-side air quality comparison using 10 years of EPA monitoring data. San Francisco, California has the edge with an Air Quality Grade of B (70/100).
| Metric | San Diego, California | San Francisco, California |
|---|---|---|
| Air Quality Grade | D (36/100) | B (70/100) |
| Current Median AQI | 67 (Moderate) | 32 (Good) |
| 5-Year Average AQI | 67 | 38 |
| 10-Year Trend | → Stable (+2) | ↓ Improving (-7) |
| Unhealthy Days/Year | 32 | 2 |
| Primary Pollutant | Fine Particulate Matter (PM2.5) | Fine Particulate Matter (PM2.5) |
Analysis
San Francisco, California outperforms San Diego, California on overall air quality. With a Grade B (70/100) and a median AQI of 32,San Francisco, California is currently in the "Good" range and is improving over the past decade.
Frequently Asked Questions
San Francisco, California has better air quality with a Grade B (70/100) compared to San Diego, California's Grade D (36/100). San Francisco, California has a current median AQI of 32 and is improving over the past decade.
San Diego, California averages 32 unhealthy air days per year (5-year average), while San Francisco, California averages 2. Unhealthy days are those when AQI exceeds 100 and sensitive groups should limit outdoor activity.
San Diego, California's primary pollutant is Fine Particulate Matter (PM2.5), while San Francisco, California's is Fine Particulate Matter (PM2.5). Both cities share the same dominant pollutant.