SmogRank / History / City race
Cities, 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.
The worst cities for PM2.5 over the 7 days to 21 Jul 2026: Marquette 183.2 µg/m³, Superior 178.2 µg/m³ and Duluth 151.1 µg/m³.
- 1MarquetteUnited States183.2
- 2SuperiorUnited States178.2
- 3DuluthUnited States151.1
- 4ManisteeUnited States117.8
- 5CloquetUnited States111.7
- 6MaumeeUnited States111.5
- 7PerrysburgUnited States111.5
- 8VirginiaUnited States110.2
- 9SarniaCanada108.4
- 10Royal OakUnited States108.3
- 11Port HuronUnited States107.4
- 12CoyhaiqueChile106.4
- 13Green BayUnited States106.2
- 14WindsorCanada105.0
- 15OregonUnited States103.6
- 16AppletonUnited States103.5
- 17Grand RapidsUnited States102.2
- 18New BaltimoreUnited States102.0
- 19DetroitUnited States100.7
- 20St. ThomasCanada99.9
+ 2,945 more cities, 99.6 µg/m³ and below
Not counted on this day, too few days measured: Ropar since 21 Jul 2026, Nohan since 21 Jul 2026 and Santa María since 10 Jul 2026.
Cities counted each 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.