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.
The worst cities in Thailand for PM2.5 over the 30 days to 9 Sep 2026: Bang Na 20.3 µg/m³, Si Maha Phot 19.3 µg/m³ and Khon Kaen 18.3 µg/m³.
- 1Bang NaBangkok20.3
- 2Si Maha PhotPrachin Buri19.3
- 3Khon KaenKhon Kaen18.3
- 4Ban ChangRayong18.1
- 5Khlong LuangPathum Thani18.0
- 6KanchanaburiKanchanaburi16.7
- 7Nong KhaemBangkok16.4
- 8Ban Talat BuengChon Buri16.4
- 9Nakhon RatchasimaNakhon Ratchasima16.0
- 10Ban Samae DamBangkok16.0
- 11Khan Na YaoBangkok15.6
- 12Phra PradaengSamut Prakan14.9
- 13Lat KrabangBangkok14.9
- 14Lak SiBangkok14.9
- 15RatchaburiRatchaburi14.6
- 16Samut SakhonSamut Sakhon14.3
- 17MukdahanMukdahan14.3
- 18RayongRayong14.0
- 19Chai NatChai Nat13.9
- 20Saphan SungBangkok13.9
+ 56 more cities, 13.9 µg/m³ and below
Cities counted each 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.