Worst air pollution Saint-Jean-sur-Richelieu, today and tomorrow

On 9 August 2026, overall air quality in Saint-Jean-sur-Richelieu is fair. AQI is the main air quality indicator at 37.4/100. Pollution peaks around 10:00 AM (O3: 37.4/100).

On 10 August 2026, air quality conditions in Saint-Jean-sur-Richelieu will be similar to today, with AQI forecast at fair at 34.1/100. Pollution peaks around 11:00 AM (O3: 34.1/100).

Seasonal air quality in Saint-Jean-sur-Richelieu is closely linked to the farmland of the Richelieu River valley surrounding it. Air quality is generally good, though spring and fall fieldwork stir up dust and occasional agricultural burning, and summer humidity can trap haze close to the ground. Wind can carry dust well beyond the fields themselves during the busiest planting and harvest weeks.

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.