Ottawa Air Quality Forecast - Today, Tomorrow
Air Quality Today
Today (10 October): Air quality in Ottawa is moderate. AQI and NO2 are moderate; PM2.5, PM10, O3, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 4:00 PM (NO2: 41.6/100).
Air Quality Tomorrow
Tomorrow (11 October 2026): Air quality in Ottawa is poor. AQI worsens to poor; PM2.5 increases to fair; NO2 increases to poor; all other pollutants stay as today. Pollution peaks around 4:00 PM (NO2: 70.0/100).
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Air Quality
Today - 10 October
| Pollutant | Level | Value |
|---|---|---|
| AQI | Moderate | 41.6/100 |
| PM2.5 (fine particles) | Good | 18.4/100 |
| PM10 (coarse particles) | Good | 11.7/100 |
| NO2 (nitrogen dioxide) | Moderate | 41.6/100 |
| O3 (ozone) | Good | 15.0/100 |
| SO2 (sulfur dioxide) | Good | 0.5/100 |
| CO (carbon monoxide) | Good | 0.6/100 |
| HCHO (formaldehyde) | Good | 1.3/100 |
| PM1 (ultrafine particles) | Good | 5.2/100 |
Tomorrow - 11 October
| Pollutant | Level | Value |
|---|---|---|
| AQI | Poor | 70.0/100 |
| PM2.5 (fine particles) | Fair | 27.1/100 |
| PM10 (coarse particles) | Good | 16.4/100 |
| NO2 (nitrogen dioxide) | Poor | 70.0/100 |
| O3 (ozone) | Good | 14.8/100 |
| SO2 (sulfur dioxide) | Good | 0.4/100 |
| CO (carbon monoxide) | Good | 0.7/100 |
| HCHO (formaldehyde) | Good | 1.8/100 |
| PM1 (ultrafine particles) | Good | 9.9/100 |
Local Environmental Conditions
Air quality in Ottawa is usually good, as the city has little heavy industry. Most local pollution comes from traffic on Highway 417, the Queensway, and the other main roads through the city, along with buses and trucks crossing the bridges to Gatineau. In winter, wood stoves and fireplaces add fine particles on cold, still nights, especially in the suburbs and rural areas. The worst days come from wildfire smoke drifting in from Quebec and northern Ontario, which has become more frequent in recent summers.
Ottawa's air quality changes with the seasons. In summer, wildfire smoke is the biggest concern: on June 25, 2023, smoke from fires in Quebec pushed Ottawa's air quality index to its highest level, and the city cancelled outdoor programs and closed its pools. Smoke returned in July 2026, though less severely. Hot, sunny days can also raise ozone. In winter, cold, still nights, averaging around -10°C in January, can trap wood smoke and traffic pollution near the ground in Ottawa.
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Frequently Asked Questions About Air Quality in Ontario
Is air quality bad in Ottawa right now?
On 10 October 2026, overall air quality in Ottawa is moderate. AQI is the main air quality indicator at 41.6/100. Pollution peaks around 4:00 PM (NO2: 41.6/100).
Will air quality be worse tomorrow in Ottawa?
On 11 October 2026, air quality conditions in Ottawa will be worse than today, with AQI forecast at poor at 70.0/100. Pollution peaks around 4:00 PM (NO2: 70.0/100).
When is air pollution at its worst in Ottawa?
Ottawa's air quality changes with the seasons. In summer, wildfire smoke is the biggest concern: on June 25, 2023, smoke from fires in Quebec pushed Ottawa's air quality index to its highest level, and the city cancelled outdoor programs and closed its pools. Smoke returned in July 2026, though less severely. Hot, sunny days can also raise ozone. In winter, cold, still nights, averaging around -10°C in January, can trap wood smoke and traffic pollution near the ground in Ottawa.
Are air quality levels in Ottawa 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.
Why doesn’t the forecast always reflect wildfire impacts?
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.
Understanding the Scale
The 0–100 air quality scores represent risk levels, not direct air pollutant concentrations. Higher scores indicate higher risk.
Air Quality
| Good | 0-20 | Low air quality risk. Air quality is expected to be good, with low levels of pollution. |
| Fair | 20-40 | Generally low air quality risk. Air quality is expected to be acceptable, with some pollution present. |
| Moderate | 40-60 | Moderate air quality risk. Air pollution is elevated and air quality may be less favorable. |
| Poor | 60-80 | High air quality risk. Air pollution is high and air quality is expected to be poor. |
| Very Poor | 80-100 | Very high air quality risk. Air pollution is very high and air quality is expected to be very poor. |