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 to10 Dec 2025 That day's board

The worst cities in Thailand for PM2.5 over the 30 days to 10 Dec 2025: Sukhothai 40.6 µg/m³, Mueang Nonthaburi 35.7 µg/m³ and Khlong Luang 34.7 µg/m³.

  1. 1SukhothaiSukhothai40.6
  2. 2Mueang NonthaburiNonthaburi35.7
  3. 3Khlong LuangPathum Thani34.7
  4. 4Khlong Sam WaBangkok34.5
  5. 5KalasinKalasin33.4
  6. 6Ban Thai TanAng Thong33.4
  7. 7Khan Na YaoBangkok33.2
  8. 8Nong KhaemBangkok33.1
  9. 9Lat KrabangBangkok32.4
  10. 10Maha SarakhamMaha Sarakham32.0
  11. 11Phra PradaengSamut Prakan31.8
  12. 12Bang NaBangkok31.2
  13. 13YasothonYasothon30.6
  14. 14PhetchaburiPhetchaburi30.4
  15. 15Mae SaiChiang Rai29.6
  16. 16Ban Samae DamBangkok29.5
  17. 17Sing BuriSing Buri29.2
  18. 18Bang KapiBangkok29.2
  19. 19Uthai ThaniUthai Thani29.1
  20. 20LamphunLamphun29.0

+ 41 more cities, 29.0 µg/m³ and below

Not counted on this day, too few days measured: Bang Pakong since 3 Nov 2025, Ratchaburi since 20 Oct 2025, Trat since 20 Oct 2025 and 7 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.