SmogRank / History / City race

Cities in Thailand, 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 to17 Apr 2025 That day's board

The worst cities in Thailand for PM2.5 over the 30 days to 17 Apr 2025: Mae Sai 72.0 µg/m³, Nan 69.4 µg/m³ and Chiang Khong 65.8 µg/m³.

  1. 1Mae SaiChiang Rai72.0
  2. 2NanNan69.4
  3. 3Chiang KhongChiang Rai65.8
  4. 4Ubon RatchathaniUbon Ratchathani62.9
  5. 5Chiang RaiChiang Rai55.7
  6. 6LamphunLamphun54.0
  7. 7PhayaoPhayao52.9
  8. 8PhraePhrae52.0
  9. 9YasothonYasothon51.8
  10. 10LoeiLoei51.5
  11. 11KalasinKalasin49.3
  12. 12Chiang MaiChiang Mai49.2
  13. 13Ban ChangRayong47.0
  14. 14SukhothaiSukhothai46.9
  15. 15Chai NatChai Nat46.6
  16. 16Amnat CharoenAmnat Charoen46.4
  17. 17Bueng KanBueng Kan46.1
  18. 18Mae SotTak45.6
  19. 19Roi EtRoi Et45.6
  20. 20MukdahanMukdahan45.5

+ 65 more cities, 45.4 µg/m³ and below

Not counted on this day, too few days measured: Lampang since 12 Apr 2025, Khon Kaen since 12 Apr 2025 and Tha Bo since 14 Mar 2025.

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.