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 to11 Feb 2026 That day's board

The worst cities in Thailand for PM2.5 over the 30 days to 11 Feb 2026: Nakhon Luang 48.4 µg/m³, Ban Thai Tan 47.4 µg/m³ and Mueang Nonthaburi 45.8 µg/m³.

  1. 1Nakhon LuangPhra Nakhon Si Ayutthaya48.4
  2. 2Ban Thai TanAng Thong47.4
  3. 3Mueang NonthaburiNonthaburi45.8
  4. 4Sing BuriSing Buri45.3
  5. 5Khlong Sam WaBangkok45.3
  6. 6Khlong LuangPathum Thani44.9
  7. 7PhetchaburiPhetchaburi44.8
  8. 8Samut SakhonSamut Sakhon44.8
  9. 9RatchaburiRatchaburi43.9
  10. 10Khan Na YaoBangkok42.3
  11. 11Lat KrabangBangkok42.2
  12. 12Uthai ThaniUthai Thani41.9
  13. 13Nakhon PathomNakhon Pathom41.9
  14. 14SaraburiSaraburi41.3
  15. 15Nong KhaemBangkok40.9
  16. 16KalasinKalasin40.2
  17. 17Bueng KumBangkok40.1
  18. 18Bang NaBangkok39.8
  19. 19Khon KaenKhon Kaen39.1
  20. 20Ban Talat BuengChon Buri39.0

+ 56 more cities, 38.8 µg/m³ and below

Not counted on this day, too few days measured: Bang Pakong since 29 Jan 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.