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 36.8/100. Pollution peaks around 9:00 AM (O3: 36.8/100).

On 10 August 2026, air quality conditions in Toronto will be similar to today, with AQI forecast at fair at 31.8/100. Pollution peaks around 12:00 PM (O3: 31.8/100).

Toronto's air quality follows a seasonal rhythm tied to its dense highway network, downtown core and lakeside high-rises. Warmer months usually bring elevated ozone and haze as heat, sunlight and vehicle emissions interact, while cooler months bring a marked improvement, apart from occasional temperature inversions that trap pollutants near the surface overnight. Local monitoring stations typically flag the sharpest changes during still, hot afternoons in July and August.

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.