Worst air pollution Downtown San Jose - San Jose, today and tomorrow
Today (15 July): Air quality in Downtown San Jose is medium. AQI and O3 are medium; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 9:00 AM (O3: 45.8/100).
Tomorrow (16 July 2026): Air quality in Downtown San Jose is fair. PM2.5 increases to fair; NO2 increases to fair; all other pollutants stay as today. Pollution peaks around 9:00 AM (O3: 44.7/100). Airmine updates local air quality forecasts four times daily.
For long term forecasts and maps, see the Airmine app
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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San Jose's Downtown air quality reflects the urban core, with vehicle traffic on Santa Clara Street and the surrounding concentrated commercial and transit hub character contributing local sources. The Bay Delta breeze provides afternoon ventilation, while the neighbourhood's walkable character and the consistent bay breezes prevent the worst pollution accumulation and Downtown San Jose generally maintains moderate Silicon Valley metropolitan readings throughout most of the year.
Today - 15 July | Pollution peaks at 09:00
AQI:
Medium
45.8/100
PM2.5 (fine particles):
Good
16.5/100
PM10 (coarse particles):
Good
10.3/100
NO2 (nitrogen dioxide):
Good
12.3/100
O3 (ozone):
Medium
45.8/100
SO2 (sulfur dioxide):
Good
3.9/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
2.6/100
PM1 (ultrafine particles):
Good
10.0/100
Levels show the poorest local air quality during the day
Tomorrow - 16 July | Pollution peaks at 09:00
AQI:
Medium
44.7/100
PM2.5 (fine particles):
Fair
21.2/100
PM10 (coarse particles):
Good
10.7/100
NO2 (nitrogen dioxide):
Fair
20.2/100
O3 (ozone):
Medium
44.7/100
SO2 (sulfur dioxide):
Good
3.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
2.2/100
PM1 (ultrafine particles):
Good
13.7/100
Other Landmarks in San Jose
Sports venues in San Jose
Frequently Asked Questions
Is air quality bad in Downtown San Jose right now?
On 15 July 2026, overall air quality in Downtown San Jose is medium. AQI is the main air quality indicator at 45.8/100. Pollution peaks around 9:00 AM (O3: 45.8/100).
Will air quality be worse tomorrow in Downtown San Jose?
On 16 July 2026, air quality conditions in Downtown San Jose will be worse than today, with PM2.5 forecast at fair at 21.2/100. Pollution peaks around 9:00 AM (O3: 44.7/100).
When is air pollution at its worst in Downtown San Jose?
Downtown San Jose follows San Jose's typical seasonal air quality pattern — winter storms periodically reset air quality, keeping the cleanest stretch to the rainy months, whereas wildfire smoke season from July through October is the dominant concern, sometimes overwhelming other pollution sources for days at a time. Dry summer conditions with virtually no rain mean pollution and smoke can linger for extended stretches once they arrive.
Are air quality levels in Downtown San Jose based on measurements or forecasts?
It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.
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Data provided by Airmine — Last update: 16 July 2026 at 10:33 CEST (Data is updated four times daily.)
This forecast is produced independently using Airmine's own atmospheric data and models.
Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.
For long term forecasts and maps, see the Airmine app