SmogRank / World / Canada / Quebec / 2025

Most polluted cities in Quebec, Canada, 2025

16 cities in Quebec, Canada ranked by their average PM2.5 over the 365 days; 16 above the WHO annual guideline (5.0 µg/m³). Worst: Sorel-Tracy at 9.3 µg/m³, #1,195 of 2,624 cities in the world. Cleanest: Saint-Jean-sur-Richelieu at 5.5. A city needs measurements on 70% of the days to be ranked.

About 41.4K people in these 4 cities breathed unhealthy air on an average day of 2025.

Ranked by people: each city's population times its share of unhealthy days, those with a daily mean over 35.4 µg/m³ (US AQI 101+). That is how many people living there breathed unhealthy air on an average day. Only cities measured at 2 or more places at least 3 km apart are ranked: one monitor shouldn't speak for a whole city. Population is the city itself, not its wider metro area.

← Montréal 29.5K 20K0
Every city in Quebec, Canada ranked for 2025 with monitors in two or more places, one column each, ranked by people breathing unhealthy air: height is people on an average day, colour its average. Point at it to read a city; tap to open it.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

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, 2025 · All cities in Canada, 2025 · Quebec now

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SmogRank, most polluted cities in Quebec, Canada, PM2.5, 2025, smogrank.com/ca/region/quebec/history/2025 (accessed 6 Oct 2026).

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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.