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 7 days to21 Sep 2023 That day's board

The worst cities for PM2.5 over the 7 days to 21 Sep 2023: Tha Bo 193.9 µg/m³, Grande Prairie 94.0 µg/m³ and Coyhaique 67.3 µg/m³.

  1. 1Tha BoThailand193.9
  2. 2Grande PrairieCanada94.0
  3. 3CoyhaiqueChile67.3
  4. 4Fort McMurrayCanada58.7
  5. 5Prince GeorgeCanada58.0
  6. 6DushanbeTajikistan52.6
  7. 7EdmontonCanada52.4
  8. 8KampalaUganda48.2
  9. 9ReginaCanada48.0
  10. 10LahorePakistan47.7
  11. 11PeshawarPakistan45.6
  12. 12Puerto VarasChile45.2
  13. 13JakartaIndonesia44.2
  14. 14Fort SaskatchewanCanada43.0
  15. 15OsornoChile41.3
  16. 16QuesnelCanada40.2
  17. 17Puerto MonttChile39.8
  18. 18NacimientoChile38.1
  19. 19La UniónChile37.8
  20. 20DhakaBangladesh37.6

+ 2,240 more cities, 37.4 µg/m³ and below

Not counted on this day, too few days measured: Alexandria since 19 Sep 2023, Kigali since 17 Sep 2023, Vientiane since 17 Sep 2023 and 5 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.