SmogRank / History / City race

Cities in Canada, worst air first, day by day

Each measured city's average over the 30 days to every day since January 2023, worst first. Find your own city to follow it through the race, or keep to one country.

CountriesCities
The 30 days to7 Aug 2026 That day's board

The worst cities in Canada for PM2.5 over the 30 days to 7 Aug 2026: Kamloops 44.7 µg/m³, Sarnia 32.8 µg/m³ and Windsor 32.4 µg/m³.

  1. 1KamloopsBritish Columbia44.7
  2. 2SarniaOntario32.8
  3. 3WindsorOntario32.4
  4. 4YellowknifeNorthwest Territories31.1
  5. 5St. ThomasOntario30.2
  6. 6Sault Ste. MarieOntario29.6
  7. 7LondonOntario29.5
  8. 8CastlegarBritish Columbia29.0
  9. 9KitchenerOntario27.4
  10. 10BrantfordOntario26.9
  11. 11VernonBritish Columbia26.0
  12. 12ChathamOntario25.5
  13. 13GuelphOntario24.5
  14. 14MiltonOntario24.3
  15. 15HamiltonOntario23.8
  16. 16CalgaryAlberta22.8
  17. 17Williams LakeBritish Columbia22.1
  18. 18EstevanSaskatchewan21.7
  19. 19CranbrookBritish Columbia21.5
  20. 20KelownaBritish Columbia21.4

+ 98 more cities, 21.3 µg/m³ and below

30 days7 days
GoodModerateSensitive groupsUnhealthyVery unhealthyHazardousWHO 24-hour guideline, 15 µg/m³Fades where it stood: not counted that day

A city's number is its average over the 30 days, shown only when 21 of them were measured (5 of 7 on the 7-day race), the same minimum as the 30- and 7-day boards. A city whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air. Some large countries are thin or missing because their monitors' licences don't allow reuse. How we rank.

Not covered: the government monitoring networks of China and Turkey, which publish only on their own websites; we are building the readers for them. Most cities there are missing from this board, not clean. Why.