Worst air pollution San Jose, today and tomorrow
Today (15 July): Air quality in 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 San Jose is medium. All pollutants stay as today. Pollution peaks around 9:00 AM (O3: 44.7/100). Airmine updates local air quality forecasts four times daily.
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Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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San Jose's air quality is shaped by the South Bay's enclosed topography, with the Santa Cruz Mountains and Diablo Range surrounding the Santa Clara Valley and trapping vehicle and technology industry emissions under frequent temperature inversions. Wildfire smoke from the surrounding coastal ranges adds periodic severe PM2.5 events during summer and autumn fire seasons.
Today - 15 July | Pollution peaks at 09:00
AQI:
Medium
45.8/100
PM2.5 (fine particles):
Good
12.3/100
PM10 (coarse particles):
Good
7.7/100
NO2 (nitrogen dioxide):
Good
1.3/100
O3 (ozone):
Medium
45.8/100
SO2 (sulfur dioxide):
Good
0.4/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
2.6/100
PM1 (ultrafine particles):
Good
7.5/100
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):
Good
16.0/100
PM10 (coarse particles):
Good
8.0/100
NO2 (nitrogen dioxide):
Good
2.1/100
O3 (ozone):
Medium
44.7/100
SO2 (sulfur dioxide):
Good
0.4/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
2.2/100
PM1 (ultrafine particles):
Good
10.2/100
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Frequently Asked Questions
Is air quality bad in San Jose right now?
On 15 July 2026, overall air quality in 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 San Jose?
On 16 July 2026, air quality conditions in San Jose will be similar to today, with AQI forecast at medium at 44.7/100. Pollution peaks around 9:00 AM (O3: 44.7/100).
When is air pollution at its worst in San Jose?
San Jose follows a fairly predictable 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 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