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 to11 Sep 2025 That day's board

The worst cities in United States for PM2.5 over the 30 days to 11 Sep 2025: Lewiston 17.0 µg/m³, Sandpoint 17.0 µg/m³ and Ephrata 16.4 µg/m³.

  1. 1LewistonIdaho17.0
  2. 2SandpointIdaho17.0
  3. 3EphrataWashington16.4
  4. 4WenatcheeWashington16.4
  5. 5ToppenishWashington15.9
  6. 6YrekaCalifornia15.7
  7. 7MoscowIdaho15.3
  8. 8Great FallsMontana14.7
  9. 9Coeur d'AleneIdaho13.9
  10. 10MeadWashington13.9
  11. 11SpokaneWashington13.8
  12. 12YakimaWashington13.7
  13. 13BakersfieldCalifornia13.6
  14. 14Columbia FallsMontana13.6
  15. 15PullmanWashington13.2
  16. 16BendOregon12.9
  17. 17Spokane ValleyWashington12.9
  18. 18HoustonTexas12.8
  19. 19CorcoranCalifornia12.8
  20. 20QuincyWashington12.7

+ 844 more cities, 12.6 µg/m³ and below

Not counted on this day, too few days measured: Northglenn since 10 Sep 2025, Middletown since 30 Jul 2025, Norwood since 25 Jul 2025 and 4 more cities.

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.