Ottawa air quality
Ontario, Canada · Live AQI and hourly forecast for the next 5 days · updated Sat 19:00 local time
Good
Great air. A perfect time to be outside.
- Next 24 hours
- 24–35US AQI, highest around Sun 17:00
- Best time outside
- Sun 01:00–4:00US AQI about 24
- PM2.5 vs WHO guideline
- 0.2×2.8 µg/m³ over 24 h, guideline 15
- Cigarette equivalent
- ≈ 0.1 a dayBerkeley Earth rule of thumb
- European AQI
- Goodlevel 1 of 6
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Pollutants in Ottawa right now
| Pollutant | Now | Next 24 h vs WHO | US AQI band |
|---|---|---|---|
| Fine particles (PM2.5) | 4.3 µg/m³ | 0.2× | Good |
| Coarse particles (PM10) | 4.4 µg/m³ | 0.1× | Good |
| Nitrogen dioxide (NO2) | 8.0 µg/m³ | 0.1× | Good |
| Ozone (O3) | 53 µg/m³ | 0.8× | Good |
| Sulphur dioxide (SO2) | 1.5 µg/m³ | 0.0× | Good |
| Carbon monoxide (CO) | 190 µg/m³ | 0.0× | Good |
| Desert dust | 0 µg/m³ | ||
| Smoke and haze (aerosol optical depth) | 0.07 | ||
| UV index | 0.0 |
“Next 24 h vs WHO” compares the forecast with the World Health Organization’s 2021 guideline levels: 24-hour means of 15 µg/m³ for PM2.5, 45 for PM10, 25 for NO2, 40 for SO2 and 4 mg/m³ for CO, and 100 µg/m³ over 8 hours for ozone. Above 1× is above the guideline.
Next 48 hours
Hourly US AQI. Highest 36 around Sun 19:00, lowest 20 around Mon 11:00.
5-day air quality forecast for Ottawa
Daily range of the hourly US AQI, from lowest to highest, on a scale of 0 to 150.
| Day | US AQI | At worst | PM2.5 avg | |
|---|---|---|---|---|
| Sat 26 Sept | 21–47 | 4.0 | ||
| Sun 27 Sept | 24–36 | 2.8 | ||
| Mon 28 Sept | 20–32 | 3.5 | ||
| Tue 29 Sept | 20–37 | 5.5 | ||
| Wed 30 Sept | 31–41 | 5.9 |
Common questions about the air in Ottawa
Is the air in Ottawa safe today?
Yes. Right now the US AQI in Ottawa is 33, which counts as good. Great air. A perfect time to be outside.
When is the best time to be outside in Ottawa?
Sun 01:00–4:00. That is the cleanest stretch in the next 24 hours, with the US AQI averaging about 24. The worst hour is around Sun 17:00, at 35.
What is the main pollutant in Ottawa?
Ozone (O3). It drives the index right now, at 53 µg/m³. Formed by sunlight acting on traffic and plant emissions. Highest on hot, still afternoons, often downwind of cities.
How does Ottawa's air compare with the WHO guideline?
Within the guideline. Over the next 24 hours PM2.5 averages about 2.8 µg/m³, against the World Health Organization's 24-hour guideline of 15 µg/m³. The other pollutants stay within their guideline levels.
How many cigarettes is a day of Ottawa's air?
About 0.1 cigarettes. Over the next 24 hours PM2.5 averages about 2.8 µg/m³. By Berkeley Earth's rule of thumb, 22 µg/m³ breathed for a day is roughly one cigarette.
Will air quality in Ottawa improve this week?
Monday looks cleanest. Its AQI peaks at 32, against 47 on Saturday, the worst day in the forecast.
Measured near Ottawa
| Station | PM2.5 µg/m³ | Measured |
|---|---|---|
| Ottawa Downtown AirNow, reference monitor | 5.0 | Sat 18:00 |
| Gatineau - Hull AirNow, reference monitor | 4.2 | Sat 18:00 |
| Unnamed sensor Sensor.Community, low-cost sensor | 1.5 | Sat 19:48 |
Air quality near Ottawa
- Montreal 166 km E
- Toronto 352 km SW
- Boston 504 km SE
- New York 541 km S
- Philadelphia 610 km S
- Detroit 682 km SW
About this forecast
Forecast from CAMS global via Open-Meteo: the Copernicus Atmosphere Monitoring Service (CAMS) model at about 40 km resolution (10 km inside Europe), refreshed twice a day. Models smooth out street-level peaks, so busy roads and industrial sites can be worse than shown; ground stations, where there are any nearby, show what monitors actually measure. The US AQI follows the US EPA scale and the European AQI the EEA bands. Readings for 45.42°N, 75.70°W, updated 2026-09-26 23:00 UTC.