Stockton Air Quality in 2020
In 2020, Stockton's air quality (Stockton-Lodi, CA area) had a median daily AQI of 54 (Moderate) across 366 monitored days. 31 days (8.5%) reached Unhealthy for Sensitive Groups or worse, 162 were Good, and the year's peak AQI was 215 (Very Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 223 of those days. The cleanest month of 2020 was March (median AQI 37, 0 days above 100) and the worst was September (median 85, 10 days above 100, peak 215).
- Good: 44.3%
- Moderate: 47.3%
- Unhealthy for Sensitive Groups: 4.4%
- Unhealthy or worse: 4.1%
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How was Stockton's air quality in 2020?
Moderate on a typical day: median AQI 54, with 31 days above AQI 100 out of 366 monitored — the 7th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2020: 215 (Very Unhealthy).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 223 days.
- ✓Cleanest month: March; worst: September.
Frequently asked questions
What was the average AQI in Stockton in 2020?▾
EPA's Air Quality System puts Stockton's (Stockton-Lodi, CA) median daily AQI for 2020 at 54, which is Moderate. 31 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 215.
Which month had the worst air quality in Stockton in 2020?▾
The cleanest month of 2020 was March (median AQI 37, 0 days above 100) and the worst was September (median 85, 10 days above 100, peak 215).
Was 2020 a good or bad year for Stockton's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2020 ranks 7th cleanest by days above AQI 100 — the worst year on record here. 2020's median of 54 is above the area's typical annual median of 48.
Stockton month by month in 2020
Stockton air quality month by month, 2020 (Stockton-Lodi, CA, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 60 | 0 | 97 | PM2.5 |
| February | 29 | 63 | 0 | 97 | PM2.5 |
| Marchcleanest | 31 | 37 | 0 | 69 | O3 |
| April | 30 | 38 | 0 | 52 | O3 |
| May | 31 | 42 | 0 | 67 | O3 |
| June | 30 | 42 | 0 | 71 | O3 |
| July | 31 | 49 | 0 | 74 | PM2.5 |
| August | 31 | 67 | 9 | 194 | PM2.5 |
| Septemberworst | 30 | 85 | 10 | 215 | PM2.5 |
| October | 31 | 71 | 5 | 181 | PM2.5 |
| November | 30 | 68 | 2 | 108 | PM2.5 |
| December | 31 | 72 | 5 | 119 | PM2.5 |
How 2020 compares
Among the 7 years EPA has published for the area (2019–2025), 2020 ranks 7th cleanest by days above AQI 100 — the worst year on record here.
2020's median of 54 is above the area's typical annual median of 48.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Stockton
The latest EPA AirNow observation puts Stockton's AQI at 49 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current Stockton air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Stockton-Lodi, 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.