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 to18 Mar 2025 That day's board

The worst cities in Thailand for PM2.5 over the 30 days to 18 Mar 2025: Mae Sai 53.3 µg/m³, Nan 51.4 µg/m³ and Lamphun 42.9 µg/m³.

  1. 1Mae SaiChiang Rai53.3
  2. 2NanNan51.4
  3. 3LamphunLamphun42.9
  4. 4PhayaoPhayao42.4
  5. 5PhraePhrae39.1
  6. 6YasothonYasothon36.8
  7. 7Ubon RatchathaniUbon Ratchathani36.0
  8. 8Chiang RaiChiang Rai35.7
  9. 9Chiang MaiChiang Mai34.6
  10. 10KanchanaburiKanchanaburi33.6
  11. 11Khon KaenKhon Kaen33.5
  12. 12UttaraditUttaradit33.3
  13. 13Bang NaBangkok32.4
  14. 14Bang PakongChachoengsao32.3
  15. 15KalasinKalasin32.1
  16. 16Sing BuriSing Buri31.3
  17. 17Si Maha PhotPrachin Buri31.3
  18. 18RatchaburiRatchaburi31.2
  19. 19SukhothaiSukhothai30.9
  20. 20PhetchabunPhetchabun30.4

+ 65 more cities, 30.3 µg/m³ and below

Not counted on this day, too few days measured: 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.