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.

CountriesCities
The 30 days to23 Aug 2023 That day's board

The worst cities for PM2.5 over the 30 days to 23 Aug 2023: Morelia 111.0 µg/m³, Coyhaique 79.8 µg/m³ and Nacimiento 72.9 µg/m³.

  1. 1MoreliaMexico111.0
  2. 2CoyhaiqueChile79.8
  3. 3NacimientoChile72.9
  4. 4ManamaBahrain60.4
  5. 5OsornoChile58.1
  6. 6Ash ShīḩānīyahQatar55.7
  7. 7San CarlosChile52.4
  8. 8LinaresChile51.6
  9. 9KamloopsCanada51.1
  10. 10DushanbeTajikistan50.1
  11. 11JakartaIndonesia50.1
  12. 12Puerto VarasChile49.4
  13. 13TemucoChile47.4
  14. 14DhakaBangladesh47.2
  15. 15ChillánChile46.4
  16. 16CoronelChile45.3
  17. 17CuranilahueChile45.2
  18. 18CuricóChile45.1
  19. 19Los ÁngelesChile45.0
  20. 20La UniónChile44.3

+ 2,053 more cities, 43.8 µg/m³ and below

Not counted on this day, too few days measured: Laja since 31 Jul 2023, Hualpén since 30 Jul 2023, Kigali since 10 Jul 2023 and Tlaquepaque since 3 Jul 2023.

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.