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 Oct 2026: Ban Chang 28.5 µg/m³, Bang Na 18.6 µg/m³ and Khon Kaen 18.5 µg/m³.
- 1Ban ChangRayong28.5
- 2Bang NaBangkok18.6
- 3Khon KaenKhon Kaen18.5
- 4Khlong LuangPathum Thani18.2
- 5Khlong Sam WaBangkok18.1
- 6Lak SiBangkok18.0
- 7Khan Na YaoBangkok17.5
- 8Lat KrabangBangkok17.3
- 9Phra PradaengSamut Prakan17.2
- 10Phra Nakhon Si AyutthayaPhra Nakhon Si Ayutthaya16.9
- 11Ban Samae DamBangkok16.9
- 12Mae SaiChiang Rai16.7
- 13Si Maha PhotPrachin Buri16.7
- 14Samut SakhonSamut Sakhon15.9
- 15Nong KhaemBangkok15.4
- 16Nakhon RatchasimaNakhon Ratchasima14.7
- 17BangkokBangkok14.7
- 18Bang KapiBangkok14.6
- 19MukdahanMukdahan14.1
- 20BetongYala14.1
+ 50 more cities, 14.1 µg/m³ and below
Not counted on this day, too few days measured: Kanchanaburi since 6 Oct 2026, Saphan Sung since 5 Oct 2026, Bang Bo District since 4 Oct 2026 and Ratchaburi since 29 Sep 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.