SmogRank / World / Canada / Ontario / February 2026
Most polluted cities in Ontario, Canada, February 2026
29 cities in Ontario, Canada ranked by their average PM2.5 over the 28 days. Worst: Windsor at 15.4 µg/m³, #759 of 2,841 cities in the world. Cleanest: Sault Ste. Marie at 5.0. A city needs measurements on 70% of the days to be ranked.
Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Ties go to the higher average.
- 1Windsor 7%
- 2Nepeanlow-cost sensors 7%
- 3Sarnia 4%
- 4London 4%
- 5Toronto 4%
- 6Cornwall 4%
- 7Milton 0%
- 8Chatham 0%
- 9Brantford 0%
- 10Waterdown 0%
- 11Hamilton 0%
- 12Oakville 0%
- 13Newmarket 0%
- 14St. Thomas 0%
- 15Guelph 0%
- 15Mississauga 0%
- 17Kitchener 0%
- 18St. Catharines 0%
- 19Brampton 0%
- 20Alliston 0%
- 21Barrie 0%
- 22Kingston 0%
- 23Belleville 0%
- 23Peterborough 0%
- 25Ottawa 0%
- 26Parry Sound 0%
- 27Greater Sudbury 0%
- 28North Bay 0%
- 29Sault Ste. Marie 0%
Low-cost sensors: consumer units, counted only in cities with no government-grade monitor; they read close to reference monitors on the whole, but 15 to 25% high in humid air. How we use them.
The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales
All cities in the world, February 2026 · All cities in Canada, February 2026 · Ontario now
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SmogRank, most polluted cities in Ontario, Canada, PM2.5, February 2026, smogrank.com/ca/region/ontario/history/2026-02 (accessed 7 Oct 2026).
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.