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 Mar 2026 That day's board

The worst cities in Thailand for PM2.5 over the 30 days to 10 Mar 2026: Nan 41.1 µg/m³, Lamphun 40.6 µg/m³ and Mae Sai 38.8 µg/m³.

  1. 1NanNan41.1
  2. 2LamphunLamphun40.6
  3. 3Mae SaiChiang Rai38.8
  4. 4PhayaoPhayao38.7
  5. 5LampangLampang38.5
  6. 6PhraePhrae37.8
  7. 7RatchaburiRatchaburi36.8
  8. 8Sing BuriSing Buri36.3
  9. 9Khlong LuangPathum Thani36.2
  10. 10Nakhon LuangPhra Nakhon Si Ayutthaya35.8
  11. 11UttaraditUttaradit35.4
  12. 12Uthai ThaniUthai Thani35.3
  13. 13Mae SotTak35.0
  14. 14Khlong Sam WaBangkok35.0
  15. 15Kamphaeng PhetKamphaeng Phet34.9
  16. 16Khan Na YaoBangkok34.3
  17. 17Mueang NonthaburiNonthaburi34.2
  18. 18Nakhon SawanNakhon Sawan33.7
  19. 19Bang NaBangkok33.3
  20. 20Khon KaenKhon Kaen33.2

+ 64 more cities, 33.0 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.