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 to12 Apr 2026 That day's board

The worst cities in Thailand for PM2.5 over the 30 days to 12 Apr 2026: Mae Sai 109.0 µg/m³, Chiang Khong 107.4 µg/m³ and Phayao 90.3 µg/m³.

  1. 1Mae SaiChiang Rai109.0
  2. 2Chiang KhongChiang Rai107.4
  3. 3PhayaoPhayao90.3
  4. 4NanNan86.7
  5. 5Chiang RaiChiang Rai81.8
  6. 6LampangLampang80.6
  7. 7Bueng KanBueng Kan79.6
  8. 8LamphunLamphun76.2
  9. 9PhraePhrae72.8
  10. 10Mae SotTak62.5
  11. 11Ubon RatchathaniUbon Ratchathani55.4
  12. 12LoeiLoei55.1
  13. 13UttaraditUttaradit54.2
  14. 14Chiang MaiChiang Mai54.1
  15. 15Nakhon SawanNakhon Sawan52.8
  16. 16Kamphaeng PhetKamphaeng Phet51.0
  17. 17PhichitPhichit47.3
  18. 18Uthai ThaniUthai Thani46.7
  19. 19Roi EtRoi Et44.3
  20. 20Amnat CharoenAmnat Charoen44.0

+ 64 more cities, 43.3 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.