Worst air pollution Ontario, today and tomorrow
Today (15 July): Air quality in Ontario is fair. AQI, PM10, and O3 are fair; PM2.5, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 8:00 AM (O3: 31.2/100).
Tomorrow (16 July 2026): Air quality in Ontario is fair. All pollutants stay as today. Pollution peaks around 9:00 AM (O3: 29.9/100). 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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Ontario's air quality in California reflects the Inland Empire basin's severe topographic enclosure, sharing San Bernardino and Riverside's California-worst air quality conditions with the additional burden of Ontario International Airport's aviation emissions and the massive Ontario Mills and Inland Center logistics and retail complex generating concentrated vehicle and freight traffic. The surrounding San Gabriel, San Bernardino, and Jurupa Hills create near-complete basin enclosure that traps emissions under the region's persistent temperature inversions.
Today - 15 July | Pollution peaks at 08:00
AQI:
Fair
31.2/100
PM2.5 (fine particles):
Good
14.4/100
PM10 (coarse particles):
Fair
22.4/100
NO2 (nitrogen dioxide):
Good
0/100
O3 (ozone):
Fair
31.2/100
SO2 (sulfur dioxide):
Good
0/100
CO (carbon monoxide):
Good
0/100
HCHO (formaldehyde):
Good
0.9/100
PM1 (ultrafine particles):
Good
2.4/100
Levels show the poorest local air quality during the day
Tomorrow - 16 July | Pollution peaks at 09:00
AQI:
Fair
29.9/100
PM2.5 (fine particles):
Good
13.3/100
PM10 (coarse particles):
Fair
23.0/100
NO2 (nitrogen dioxide):
Good
0/100
O3 (ozone):
Fair
29.9/100
SO2 (sulfur dioxide):
Good
0/100
CO (carbon monoxide):
Good
0/100
HCHO (formaldehyde):
Good
1.0/100
PM1 (ultrafine particles):
Good
2.6/100
Pollen forecast in Ontario
View pollen forecastFrequently Asked Questions
Is air quality bad in Ontario right now?
On 15 July 2026, overall air quality in Ontario is fair. AQI is the main air quality indicator at 31.2/100. Pollution peaks around 8:00 AM (O3: 31.2/100).
Will air quality be worse tomorrow in Ontario?
On 16 July 2026, air quality conditions in Ontario will be similar to today, with AQI forecast at fair at 29.9/100. Pollution peaks around 9:00 AM (O3: 29.9/100).
When is air pollution at its worst in Ontario?
Like most US cities, Ontario sees air quality shift from season to season: the shortest stretch of clean air usually falls in the wetter winter months, but summer and early autumn bring the highest ozone levels, and wildfire smoke can spike particulate readings sharply from August through October. Coastal breezes offer some relief compared to inland valley locations that see heavier smog buildup.
Are air quality levels in Ontario 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