San Diego Air Quality in 2019
In 2019, San Diego's air quality (San Diego-Carlsbad, CA area) had a median daily AQI of 66 (Moderate) across 365 monitored days. 25 days (6.8%) reached Unhealthy for Sensitive Groups or worse, 38 were Good, and the year's peak AQI was 169 (Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 228 of those days. The cleanest month of 2019 was February (median AQI 52, 0 days above 100) and the worst was July (median 84, 7 days above 100, peak 159).
- Good: 10.4%
- Moderate: 82.7%
- Unhealthy for Sensitive Groups: 6.3%
- Unhealthy or worse: 0.5%
Extra Protection for San Diego Homes
Air quality in San Diego is moderate (AQI 53), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
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How was San Diego's air quality in 2019?
Moderate on a typical day: median AQI 66, with 25 days above AQI 100 out of 365 monitored — the 2nd cleanest of 7 years on record for the area.
- ✓Peak AQI in 2019: 169 (Unhealthy).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 228 days.
- ✓Cleanest month: February; worst: July.
Frequently asked questions
What was the average AQI in San Diego in 2019?▾
EPA's Air Quality System puts San Diego's (San Diego-Carlsbad, CA) median daily AQI for 2019 at 66, which is Moderate. 25 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 169.
Which month had the worst air quality in San Diego in 2019?▾
The cleanest month of 2019 was February (median AQI 52, 0 days above 100) and the worst was July (median 84, 7 days above 100, peak 159).
Was 2019 a good or bad year for San Diego's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2019 ranks 2nd cleanest by days above AQI 100. 2019's median of 66 is in line with the area's typical annual median of 67.
San Diego month by month in 2019
San Diego air quality month by month, 2019 (San Diego-Carlsbad, CA, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 58 | 1 | 101 | PM2.5 |
| Februarycleanest | 28 | 52 | 0 | 71 | PM2.5 |
| March | 31 | 52 | 1 | 101 | PM2.5 |
| April | 30 | 68 | 2 | 105 | PM2.5 |
| May | 31 | 55 | 0 | 87 | PM2.5 |
| June | 30 | 64 | 2 | 112 | PM2.5 |
| Julyworst | 31 | 84 | 7 | 159 | O3 |
| August | 31 | 80 | 5 | 169 | O3 |
| September | 30 | 66 | 1 | 147 | PM2.5 |
| October | 31 | 77 | 4 | 123 | PM2.5 |
| November | 30 | 74 | 2 | 103 | PM2.5 |
| December | 31 | 60 | 0 | 85 | PM2.5 |
How 2019 compares
Among the 7 years EPA has published for the area (2019–2025), 2019 ranks 2nd cleanest by days above AQI 100.
2019's median of 66 is in line with the area's typical annual median of 67.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in San Diego
The latest EPA AirNow observation puts San Diego's AQI at 53 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current San Diego air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (San Diego-Carlsbad, CA), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.