Worst air pollution Toronto, today and tomorrow

On 9 August 2026, overall air quality in Toronto is fair. AQI is the main air quality indicator at 34.2/100. Pollution peaks around 9:00 AM (O3: 34.2/100).

On 10 August 2026, air quality conditions in Toronto will be similar to today, with AQI forecast at fair at 35.6/100. Pollution peaks around 10:00 AM (O3: 35.6/100).

Winter around Toronto typically brings the year's highest particulate readings, as heating and traffic emissions build up under calm, cold air. Summer heat and sunlight typically push ozone to the top of the seasonal concerns here. Regional wildfire smoke can occasionally push readings higher during otherwise typical summer weather. Spring and fall generally stand out as the cleanest stretches of the year, aided by gentler weather.

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.

Airmine’s forecast uses CAMS (Copernicus Atmosphere Monitoring Service) as its background atmospheric model. While CAMS includes wildfire emissions, these are derived from satellite observations and are not available in real time. During rapidly evolving wildfire events, there may therefore be a delay before increased emissions are incorporated into the model. As a result, the forecast may temporarily underestimate PM₂.₅ and other pollutants associated with wildfire smoke.

During rapidly evolving wildfire events, CAMS may lag by approximately 1–2 days before increased wildfire emissions are fully represented, which can lead to temporary underestimation of PM₂.₅ concentrations in Airmine’s forecast.