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 to8 Feb 2026 That day's board

The worst cities in Thailand for PM2.5 over the 30 days to 8 Feb 2026: Nakhon Luang 48.2 µg/m³, Ban Thai Tan 48.2 µg/m³ and Samut Sakhon 46.3 µg/m³.

  1. 1Nakhon LuangPhra Nakhon Si Ayutthaya48.2
  2. 2Ban Thai TanAng Thong48.2
  3. 3Samut SakhonSamut Sakhon46.3
  4. 4Sing BuriSing Buri46.1
  5. 5PhetchaburiPhetchaburi45.6
  6. 6Mueang NonthaburiNonthaburi45.5
  7. 7Khlong LuangPathum Thani45.3
  8. 8Khlong Sam WaBangkok45.2
  9. 9RatchaburiRatchaburi44.2
  10. 10Nakhon PathomNakhon Pathom43.5
  11. 11Uthai ThaniUthai Thani43.1
  12. 12Khan Na YaoBangkok42.3
  13. 13Lat KrabangBangkok41.7
  14. 14Nong KhaemBangkok41.5
  15. 15KalasinKalasin41.3
  16. 16SaraburiSaraburi41.1
  17. 17Bueng KumBangkok40.2
  18. 18Bang NaBangkok39.6
  19. 19Chai NatChai Nat39.4
  20. 20Nakhon RatchasimaNakhon Ratchasima38.9

+ 55 more cities, 38.6 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.