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 to9 Apr 2026 That day's board

The worst cities in Thailand for PM2.5 over the 30 days to 9 Apr 2026: Mae Sai 101.9 µg/m³, Chiang Khong 98.4 µg/m³ and Phayao 83.5 µg/m³.

  1. 1Mae SaiChiang Rai101.9
  2. 2Chiang KhongChiang Rai98.4
  3. 3PhayaoPhayao83.5
  4. 4NanNan81.3
  5. 5LampangLampang78.9
  6. 6Chiang RaiChiang Rai75.2
  7. 7LamphunLamphun71.0
  8. 8PhraePhrae68.0
  9. 9Bueng KanBueng Kan67.9
  10. 10Mae SotTak60.9
  11. 11UttaraditUttaradit52.2
  12. 12Ubon RatchathaniUbon Ratchathani51.3
  13. 13Nakhon SawanNakhon Sawan51.2
  14. 14LoeiLoei51.0
  15. 15Chiang MaiChiang Mai49.1
  16. 16Kamphaeng PhetKamphaeng Phet47.8
  17. 17Uthai ThaniUthai Thani44.1
  18. 18PhichitPhichit42.7
  19. 19Amnat CharoenAmnat Charoen41.7
  20. 20Chai NatChai Nat41.1

+ 65 more cities, 40.3 µg/m³ and below

Not counted on this day, too few days measured: Khon Kaen since 26 Mar 2026.

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.