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 to8 Apr 2023 That day's board

The worst cities for PM2.5 over the 7 days to 8 Apr 2023: Mae Sai 261.0 µg/m³, Chiang Khong 201.2 µg/m³ and Ban Houakhoua 201.2 µg/m³.

  1. 1Mae SaiThailand261.0
  2. 2Chiang KhongThailand201.2
  3. 3Ban HouakhouaLaos201.2
  4. 4Chiang RaiThailand169.3
  5. 5PhayaoThailand154.0
  6. 6Chiang MaiThailand151.8
  7. 7N'DjamenaChad145.2
  8. 8NanThailand139.0
  9. 9LoeiThailand129.0
  10. 10LampangThailand120.8
  11. 11LamphunThailand113.2
  12. 12Tha BoThailand105.1
  13. 13VientianeLaos105.1
  14. 14PhraeThailand94.8
  15. 15DhakaBangladesh93.6
  16. 16BamakoMali85.4
  17. 17UttaraditThailand71.3
  18. 18Bueng KanThailand69.8
  19. 19PakxanLaos69.8
  20. 20SukhothaiThailand69.6

+ 1,810 more cities, 68.6 µg/m³ and below

Not counted on this day, too few days measured: Udon Thani since 7 Apr 2023, Mukdahan since 6 Apr 2023, Tak since 3 Apr 2023 and 12 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.