Air quality in Canada
Air quality in Ontario today
Updated
Good: average US AQI 45 across 36 cities in Ontario Worst now: Windsor (77); cleanest: North Bay (27).
Live US AQI, PM2.5 and ozone for cities across Ontario, compared with the Canada average.
- Average US AQI
- 45 Good
- Canada average
- 43 78 cities
- Most polluted now
- Windsor AQI 77
- Cleanest now
- North Bay AQI 27
- Cities above 100
- 0
Air quality in Ontario today
Right now the modelled air quality in Ontario averages a US AQI of 45 (Good) across the 36 cities we track. By category: 21 Good, 15 Moderate (of 36).
That is close to the Canada average of 43, ranking 9 of 10 provinces from cleanest to most polluted.
Windsor has the worst air at 77 (PM2.5 15 µg/m³), and North Bay the cleanest at 27. No tracked city is above 100, so no group needs to change plans.
Ontario cities by AQI (most polluted first)
| City | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Windsor | 77 | Moderate | 15.3 | 15 | 77 |
| Aurora | 57 | Moderate | 5.6 | 6 | 82 |
| Ottawa | 56 | Moderate | 4.7 | 5 | 63 |
| Mississauga | 56 | Moderate | 6.8 | 7 | 82 |
| Brampton | 56 | Moderate | 6.8 | 7 | 82 |
| Oakville | 56 | Moderate | 6.8 | 7 | 82 |
| Burlington | 56 | Moderate | 6.8 | 7 | 82 |
| Orléans | 56 | Moderate | 4.7 | 5 | 63 |
| Ottawa South | 56 | Moderate | 4.7 | 5 | 63 |
| Georgetown | 56 | Moderate | 4.7 | 5 | 90 |
| Barrie | 54 | Moderate | 5.1 | 5 | 81 |
| Sarnia | 53 | Moderate | 8.7 | 9 | 89 |
| Wasaga Beach | 52 | Moderate | 4.5 | 5 | 88 |
| Kitchener | 51 | Moderate | 5.1 | 5 | 95 |
| Waterloo | 51 | Moderate | 5.1 | 5 | 95 |
| Nepean | 50 | Good | 3.8 | 4 | 71 |
| Gloucester | 50 | Good | 3.8 | 4 | 71 |
| Markham | 47 | Good | 7.3 | 7 | 77 |
| Cambridge | 47 | Good | 4.3 | 4 | 95 |
| Brantford | 47 | Good | 4.3 | 4 | 95 |
| Kingston | 45 | Good | 4 | 4 | 84 |
| Hamilton | 44 | Good | 5.2 | 5 | 91 |
| Toronto | 35 | Good | 8.7 | 9 | 80 |
| Etobicoke | 35 | Good | 8.7 | 9 | 80 |
| Vaughan | 35 | Good | 8.7 | 9 | 80 |
| Richmond Hill | 35 | Good | 8.7 | 9 | 80 |
| Whitby | 35 | Good | 7.3 | 7 | 78 |
| Thornhill | 35 | Good | 8.7 | 9 | 80 |
| Peterborough | 34 | Good | 4.5 | 5 | 78 |
| Grimsby | 33 | Good | 5.6 | 6 | 90 |
| London | 32 | Good | 5.6 | 6 | 93 |
| St. Thomas | 32 | Good | 5.6 | 6 | 93 |
| Niagara Falls | 31 | Good | 3.6 | 4 | 101 |
| Cornwall | 30 | Good | 2.7 | 3 | 74 |
| Thunder Bay | 29 | Good | 1.4 | 2 | 71 |
| North Bay | 27 | Good | 5.4 | 5 | 77 |
What the US AQI numbers mean
| US AQI | Category | What it means |
|---|---|---|
| 0-50 | Good | Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. |
| 51-100 | Moderate | Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. |
| 101-150 | Unhealthy for Sensitive Groups | People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. |
| 151-200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should avoid it and keep windows closed. |
| 201-300 | Very Unhealthy | Health alert: everyone should avoid prolonged or heavy exertion outdoors, and sensitive groups should stay indoors. |
| 301-500 | Hazardous | Emergency conditions: everyone should avoid all outdoor physical activity and stay indoors with filtered air if possible. The scale tops out at 500; heavier dust or smoke is shown as 500. |
Modelled by CAMS (Copernicus) via Open-Meteo, refreshed twice a day; read hour by hour from the forecast.
Cities in Ontario
- Air quality in Toronto
- Air quality in Ottawa
- Air quality in Mississauga
- Air quality in Brampton
- Air quality in Hamilton
- Air quality in London
- Air quality in Etobicoke
- Air quality in Markham
- Air quality in Vaughan
- Air quality in Kitchener
- Air quality in Windsor
- Air quality in Oakville
- Air quality in Richmond Hill
- Air quality in Burlington
- Air quality in Nepean
- Air quality in Oshawa
- Air quality in Greater Sudbury
- Air quality in Gloucester
- Air quality in Barrie
- Air quality in Guelph
- Air quality in Whitby
- Air quality in St. Catharines
- Air quality in Milton
- Air quality in Kingston
- Air quality in Cambridge
- Air quality in Orléans
- Air quality in Ottawa South
- Air quality in Ajax
- Air quality in Thornhill
- Air quality in Thunder Bay
- Air quality in Waterloo
- Air quality in Brantford
- Air quality in Niagara Falls
- Air quality in Peterborough
- Air quality in Sarnia
- Air quality in Aurora
- Air quality in North Bay
- Air quality in Cornwall
- Air quality in Georgetown
- Air quality in St. Thomas
More
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS).