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 to23 Sep 2023 That day's board

The worst cities for PM2.5 over the 7 days to 23 Sep 2023: Tha Bo 139.9 µg/m³, Coyhaique 74.4 µg/m³ and Grande Prairie 55.1 µg/m³.

  1. 1Tha BoThailand139.9
  2. 2CoyhaiqueChile74.4
  3. 3Grande PrairieCanada55.1
  4. 4KampalaUganda53.8
  5. 5Puerto VarasChile53.6
  6. 6Fort McMurrayCanada52.5
  7. 7LahorePakistan49.2
  8. 8OsornoChile47.4
  9. 9JakartaIndonesia42.6
  10. 10La UniónChile41.6
  11. 11PeshawarPakistan41.0
  12. 12Puerto MonttChile39.8
  13. 13DushanbeTajikistan39.4
  14. 14NacimientoChile38.9
  15. 15EdmontonCanada38.7
  16. 16RancaguaChile36.0
  17. 17YrekaUnited States35.4
  18. 18ReginaCanada34.8
  19. 19Addis AbabaEthiopia34.6
  20. 20Puente AltoChile34.3

+ 2,237 more cities, 34.2 µg/m³ and below

Not counted on this day, too few days measured: Alexandria since 19 Sep 2023, Kigali since 17 Sep 2023, Victoria de Durango since 14 Sep 2023 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.