Worst air pollution Westminster, today and tomorrow
Today (15 July): Air quality in Westminster is fair. AQI, PM10, and O3 are fair; PM2.5, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 7:00 AM (O3: 30.4/100).
Tomorrow (16 July 2026): Air quality in Westminster is fair. All pollutants stay as today. Pollution peaks around 9:00 AM (O3: 29.7/100). 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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Westminster's air quality in California reflects the Orange County portion of the Los Angeles basin, with vehicle emissions from the Garden Grove Freeway SR-22 and I-405 the primary local sources. The basin inversion affects all of Orange County, while Pacific sea breezes provide better afternoon ventilation than the deeper San Fernando Valley and Westminster's central Orange County position generally tracks at moderate Los Angeles basin levels throughout the year.
Today - 15 July | Pollution peaks at 07:00
AQI:
Fair
30.4/100
PM2.5 (fine particles):
Good
14.6/100
PM10 (coarse particles):
Fair
23.0/100
NO2 (nitrogen dioxide):
Good
0.3/100
O3 (ozone):
Fair
30.4/100
SO2 (sulfur dioxide):
Good
0.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
0.9/100
PM1 (ultrafine particles):
Good
2.7/100
Levels show the poorest local air quality during the day
Tomorrow - 16 July | Pollution peaks at 09:00
AQI:
Fair
29.7/100
PM2.5 (fine particles):
Good
11.8/100
PM10 (coarse particles):
Fair
20.1/100
NO2 (nitrogen dioxide):
Good
0.4/100
O3 (ozone):
Fair
29.7/100
SO2 (sulfur dioxide):
Good
1.0/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
0.9/100
PM1 (ultrafine particles):
Good
2.7/100
Pollen forecast in Westminster
View pollen forecastFrequently Asked Questions
Is air quality bad in Westminster right now?
On 15 July 2026, overall air quality in Westminster is fair. AQI is the main air quality indicator at 30.4/100. Pollution peaks around 7:00 AM (O3: 30.4/100).
Will air quality be worse tomorrow in Westminster?
On 16 July 2026, air quality conditions in Westminster will be similar to today, with AQI forecast at fair at 29.7/100. Pollution peaks around 9:00 AM (O3: 29.7/100).
When is air pollution at its worst in Westminster?
Conditions in Westminster vary noticeably across the seasons: winter typically brings the cleanest stretch, once occasional rain clears the basin, but summer sunshine and heat drive some of the worst ozone readings in the country. Coastal breezes offer some relief compared to inland valley locations that see heavier smog buildup.
Are air quality levels in Westminster 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