Worst air pollution Walnut Creek, today and tomorrow
Today (15 July): Air quality in Walnut Creek is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 9:00 AM (O3: 37.9/100).
Tomorrow (16 July 2026): Air quality in Walnut Creek is fair. AQI improves to medium; PM2.5 increases to fair; O3 decreases to medium; all other pollutants stay as today. Pollution peaks around 10:00 AM (O3: 40.2/100). 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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Walnut Creek's air quality reflects the Diablo Valley position in the East Bay, with vehicle emissions from SR-24 and I-680 the primary local source. The Bay Delta breeze from the Caldecott Tunnel corridor and the Carquinez Strait generally provides afternoon ventilation on most days, while summer wildfire smoke from the Mount Diablo range and surrounding East Bay Regional Parks is an increasingly frequent and severe seasonal concern throughout the year.
Today - 15 July | Pollution peaks at 09:00
AQI:
Fair
37.9/100
PM2.5 (fine particles):
Good
13.5/100
PM10 (coarse particles):
Good
8.5/100
NO2 (nitrogen dioxide):
Good
7.2/100
O3 (ozone):
Fair
37.9/100
SO2 (sulfur dioxide):
Good
2.3/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
1.8/100
PM1 (ultrafine particles):
Good
7.3/100
Levels show the poorest local air quality during the day
Tomorrow - 16 July | Pollution peaks at 10:00
AQI:
Medium
40.2/100
PM2.5 (fine particles):
Fair
20.2/100
PM10 (coarse particles):
Good
9.7/100
NO2 (nitrogen dioxide):
Good
16.0/100
O3 (ozone):
Medium
40.2/100
SO2 (sulfur dioxide):
Good
2.3/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
1.7/100
PM1 (ultrafine particles):
Good
13.5/100
Pollen forecast in Walnut Creek
View pollen forecastFrequently Asked Questions
Is air quality bad in Walnut Creek right now?
On 15 July 2026, overall air quality in Walnut Creek is fair. AQI is the main air quality indicator at 37.9/100. Pollution peaks around 9:00 AM (O3: 37.9/100).
Will air quality be worse tomorrow in Walnut Creek?
On 16 July 2026, air quality conditions in Walnut Creek will be similar to today, with PM2.5 forecast at fair at 20.2/100. Pollution peaks around 10:00 AM (O3: 40.2/100).
When is air pollution at its worst in Walnut Creek?
Like most US cities, Walnut Creek sees air quality shift from season to season. In short, winter typically brings the cleanest stretch, once occasional rain clears the basin, whereas from August into October, wildfire smoke can add sharp particulate spikes on top of the usual summer ozone. The mountains ringing the basin can trap pollution close to the ground for days when winds are calm.
Are air quality levels in Walnut Creek 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