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 6 Sep 2026: Bang Na 19.9 µg/m³, Si Maha Phot 19.2 µg/m³ and Khon Kaen 18.2 µg/m³.
- 1Bang NaBangkok19.9
- 2Si Maha PhotPrachin Buri19.2
- 3Khon KaenKhon Kaen18.2
- 4Khlong LuangPathum Thani17.9
- 5KanchanaburiKanchanaburi17.2
- 6Ban ChangRayong17.1
- 7Nong KhaemBangkok16.3
- 8Nakhon RatchasimaNakhon Ratchasima15.9
- 9Ban Samae DamBangkok15.6
- 10Khan Na YaoBangkok15.3
- 11Phra PradaengSamut Prakan14.8
- 12Lat KrabangBangkok14.8
- 13Lak SiBangkok14.8
- 14RatchaburiRatchaburi14.7
- 15MukdahanMukdahan14.4
- 16RayongRayong14.1
- 17Samut SakhonSamut Sakhon13.9
- 18Chai NatChai Nat13.8
- 19Saphan SungBangkok13.8
- 20Khlong Sam WaBangkok13.8
+ 55 more cities, 13.1 µg/m³ and below
Not counted on this day, too few days measured: Bang Bo District since 5 Sep 2026, Phetchaburi since 10 Jul 2026 and Sadao since 10 Jul 2026.
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.