San Diego, California Air Quality
San Diego air quality today — the AQI, the main pollutant, and whether it’s safe to exercise outside right now
San Diego, CA · Air quality right now
The air quality index in San Diego, CA is 59 (Moderate) right now — acceptable for most people.
Is it safe to be outside in San Diego today?
AQI 59 Yes — air quality is Moderate
Fine for most; unusually sensitive people can take it easy.Main pollutant: PM2.5Observed 12:00 AM PDT
Pollutants right now
- PM2.514 µg/m³Main pollutantfine particles — smoke, exhaust, soot
- PM1018 µg/m³coarse particles — dust, pollen, ash
- Ozone33 µg/m³smog — builds on hot, sunny days
- NO₂35 µg/m³nitrogen dioxide — traffic, combustion
ExerciseOK to run for most; sensitive athletes can ease the intensity.
How to read San Diego’s air quality
Guides: The AQI Scale, Explained · Air Quality Alerts, Decoded · How to Read a Wildfire Smoke Map · Why Wildfire Smoke Travels 1,000 Miles.
Air quality over time in San Diego
Across the EPA’s county records from 2020 to 2025, San Diego’s cleanest year was 2022 (median AQI 63) and its most polluted was 2020 (median AQI 74); the typical (median) day has held roughly steady since 2020.
| Year | Median AQI | Unhealthy+ | Main pollutant | USG | Moderate | Good |
|---|---|---|---|---|---|---|
| 2020 | 74 | 14 | PM2.5 | 35 | 284 | 33 |
| 2021 | 67 | 0 | PM2.5 | 16 | 297 | 52 |
| 2022 | 63 | 1 | PM2.5 | 25 | 297 | 42 |
| 2023 | 67 | 0 | Ozone | 44 | 260 | 61 |
| 2024 | 71 | 4 | Ozone | 48 | 267 | 47 |
| 2025 | 67 | 7 | PM2.5 | 26 | 268 | 64 |
“USG” is Unhealthy for Sensitive Groups (AQI 101–150); “Unhealthy+” combines the Unhealthy, Very Unhealthy, and Hazardous days. In 2024 the EPA tightened the annual fine-particle (PM2.5) standard to 9 µg/m³ from the previous 12 µg/m³, so counties near the old limit read worse against the new one. Source: EPA AQS annual summaries, 2020–2025.
Frequently asked
- What was the worst year for air quality in San Diego?
- In the EPA's 2020–2025 county records, 2024 had the most days above AQI 100: 52 days (48 Unhealthy for Sensitive Groups, 4 Unhealthy or worse). The highest median AQI came in 2020 (74; 2024's was 71).
- How many unhealthy air days does San Diego have?
- Across 2020–2025, 10% of the days reported for San Diego's county had an AQI above 100 (220 of 2192), about 37 days a year. 2025 had 33 days.
- What's the main air pollutant in San Diego?
- PM2.5 drove San Diego's county AQI on the most days in 4 of 6 years (2020–2025); Ozone in 2023, 2024.