SmogRank / History / City race

Cities in United States, 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 United States for PM2.5 over the 30 days to 7 Aug 2026: Prineville 54.2 µg/m³, Marquette 50.3 µg/m³ and Superior 49.9 µg/m³.

  1. 1PrinevilleOregon54.2
  2. 2MarquetteMichigan50.3
  3. 3SuperiorWisconsin49.9
  4. 4La GrandeOregon45.2
  5. 5DuluthMinnesota44.3
  6. 6NampaIdaho43.0
  7. 7Baker CityOregon41.5
  8. 8OntarioOregon41.5
  9. 9MaumeeOhio37.8
  10. 10PerrysburgOhio37.8
  11. 11WeiserIdaho37.1
  12. 12Royal OakMichigan36.6
  13. 13ManisteeMichigan34.1
  14. 14VirginiaMinnesota33.5
  15. 15OregonOhio33.3
  16. 16CloquetMinnesota32.9
  17. 17Green BayWisconsin32.8
  18. 18DearbornMichigan32.7
  19. 19BoiseIdaho32.7
  20. 20Port HuronMichigan32.4

+ 840 more cities, 31.8 µg/m³ and below

Not counted on this day, too few days measured: West Sedona since 20 Jul 2026.

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.