SmogRank / World / Canada / Ontario / November 2023
Most polluted cities in Ontario, Canada, November 2023
29 cities in Ontario, Canada ranked by their average PM2.5 over the 30 days. Worst: Windsor at 10.3 µg/m³, #531 of 2,194 cities in the world. Cleanest: Thunder Bay at 4.4. 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 0%
- 2Sarnia 0%
- 3Brantford 0%
- 3Chatham 0%
- 5Kitchener 0%
- 5London 0%
- 5Toronto 0%
- 8Hamilton 0%
- 9Milton 0%
- 10Oakville 0%
- 10Waterdown 0%
- 12Guelph 0%
- 13Mississauga 0%
- 13St. Thomas 0%
- 15Barrie 0%
- 16Brampton 0%
- 17Newmarket 0%
- 18St. Catharines 0%
- 19Peterborough 0%
- 20Cornwall 0%
- 21Ottawa 0%
- 22Belleville 0%
- 23Brooklin 0%
- 24Kingston 0%
- 25Greater Sudbury 0%
- 26Parry Sound 0%
- 27North Bay 0%
- 28Sault Ste. Marie 0%
- 29Thunder Bay 0%
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, November 2023 · All cities in Canada, November 2023 · Ontario now
Use this board
SmogRank, most polluted cities in Ontario, Canada, PM2.5, November 2023, smogrank.com/ca/region/ontario/history/2023-11 (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.