San Jose Air Quality in 2024
In 2024, San Jose's air quality (San Jose-Sunnyvale-Santa Clara, CA area) had a median daily AQI of 51 (Moderate) across 366 monitored days. 2 days (0.5%) reached Unhealthy for Sensitive Groups or worse, 183 were Good, and the year's peak AQI was 111 (Unhealthy for Sensitive Groups). Fine particulate matter (PM2.5) set the daily AQI on 229 of those days. The cleanest month of 2024 was March (median AQI 37, 0 days above 100) and the worst was July (median 58, 2 days above 100, peak 111).
- Good: 50.0%
- Moderate: 49.5%
- Unhealthy for Sensitive Groups: 0.5%
- Unhealthy or worse: 0.0%
Extra Protection for San Jose Homes
Air quality in San Jose 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.
Recommended: Coway AP-1512HH Mighty — True HEPA + carbon · CADR ~246 CFM · rooms up to 361 sq ft
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How was San Jose's air quality in 2024?
Moderate on a typical day: median AQI 51, with 2 days above AQI 100 out of 366 monitored — the 2nd cleanest of 7 years on record for the area.
- ✓Peak AQI in 2024: 111 (Unhealthy for Sensitive Groups).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 229 days.
- ✓Cleanest month: March; worst: July.
Frequently asked questions
What was the average AQI in San Jose in 2024?▾
EPA's Air Quality System puts San Jose's (San Jose-Sunnyvale-Santa Clara, CA) median daily AQI for 2024 at 51, which is Moderate. 2 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 111.
Which month had the worst air quality in San Jose in 2024?▾
The cleanest month of 2024 was March (median AQI 37, 0 days above 100) and the worst was July (median 58, 2 days above 100, peak 111).
Was 2024 a good or bad year for San Jose's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2024 ranks 2nd cleanest by days above AQI 100. 2024's median of 51 is in line with the area's typical annual median of 50.
San Jose month by month in 2024
San Jose air quality month by month, 2024 (San Jose-Sunnyvale-Santa Clara, CA, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 42 | 0 | 80 | PM2.5 |
| February | 29 | 38 | 0 | 70 | O3 |
| Marchcleanest | 31 | 37 | 0 | 46 | O3 |
| April | 30 | 47 | 0 | 67 | PM2.5 |
| May | 31 | 51 | 0 | 65 | PM2.5 |
| June | 30 | 54 | 0 | 74 | PM2.5 |
| Julyworst | 31 | 58 | 2 | 111 | PM2.5 |
| August | 31 | 54 | 0 | 80 | O3 |
| September | 30 | 49 | 0 | 74 | PM2.5 |
| October | 31 | 53 | 0 | 77 | PM2.5 |
| November | 30 | 49 | 0 | 78 | PM2.5 |
| December | 31 | 59 | 0 | 100 | PM2.5 |
How 2024 compares
Among the 7 years EPA has published for the area (2019–2025), 2024 ranks 2nd cleanest by days above AQI 100.
2024's median of 51 is in line with the area's typical annual median of 50.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in San Jose
The latest EPA AirNow observation puts San Jose's AQI at 53 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current San Jose air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (San Jose-Sunnyvale-Santa Clara, 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.