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 12 Jan 2026: Samut Sakhon 47.2 µg/m³, Nakhon Pathom 38.6 µg/m³ and Mueang Nonthaburi 36.0 µg/m³.
- 1Samut SakhonSamut Sakhon47.2
- 2Nakhon PathomNakhon Pathom38.6
- 3Mueang NonthaburiNonthaburi36.0
- 4Khlong Sam WaBangkok35.4
- 5Ban Thai TanAng Thong35.0
- 6Uthai ThaniUthai Thani34.4
- 7Nong KhaemBangkok34.1
- 8Khan Na YaoBangkok33.6
- 9PhetchaburiPhetchaburi33.4
- 10RatchaburiRatchaburi33.4
- 11Sing BuriSing Buri33.2
- 12Bang PakongChachoengsao32.8
- 13Bang NaBangkok31.4
- 14Ban Samae DamBangkok31.3
- 15LamphunLamphun31.1
- 16Phra PradaengSamut Prakan30.8
- 17Bueng KumBangkok30.3
- 18Nakhon LuangPhra Nakhon Si Ayutthaya30.2
- 19Saphan SungBangkok30.0
- 20Maha SarakhamMaha Sarakham29.8
+ 54 more cities, 29.8 µg/m³ and below
Not counted on this day, too few days measured: Sukhothai since 5 Jan 2026 and Khlong Luang since 2 Jan 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.