SmogRank / World / Canada / Quebec / August 2025

Most polluted cities in Quebec, Canada, August 2025

16 cities in Quebec, Canada ranked by their average PM2.5 over the 31 days. Worst: Granby at 12.8 µg/m³, #576 of 2,841 cities in the world. Cleanest: Sept-Îles at 7.8. 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.

← Rouyn-Noranda 13% 10%0

Every city in Quebec, Canada ranked for August 2025, one column each, ranked by unhealthy days: height is the share of its measured days that were unhealthy, colour its average. Point at it to read a city; tap to open it.

1Rouyn-Noranda
13%
2Granby
8%
3Dorval
6%
4Montréal
6%
5L'Ancienne-Lorette
4%
6Sorel-Tracy
3%
7Québec
3%
8Saguenay
3%
8Trois-Rivières
3%
8Rivière-des-Prairies–Pointe-aux-Trembles
3%
11Drummondville
3%
12Shawinigan
3%
13Sherbrooke
3%
14Bécancour
0%
15Saint-Jean-sur-Richelieu
0%
16Sept-Îles
0%

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

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SmogRank, most polluted cities in Quebec, Canada, PM2.5, August 2025, smogrank.com/ca/region/quebec/history/2025-08 (accessed 6 Oct 2026).

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