SmogRank / Countries / Thailand / 2025

Most polluted cities in Thailand, 2025

5 cities in Thailand ranked by their average PM2.5 over the 365 days; 5 above the WHO annual guideline (5.0 µg/m³). Worst: Chiang Mai at 22.9 µg/m³, #141 of 2,131 cities in the world. Cleanest: Bang Pakong at 17.6. A city needs measurements on 70% of the days to be ranked.

  1. 1Chiang Mailow-cost sensorsChiang Mai
    22.94.6×
  2. 2Sai Mailow-cost sensorsBangkok
    21.74.3×
  3. 3Bangkoklow-cost sensorsBangkok
    21.44.3×
  4. 4Khlong Luanglow-cost sensorsPathum Thani
    18.23.6×
  5. 5Bang Pakonglow-cost sensorsChachoengsao
    17.63.5×
Good0–9.0
Moderate9.1–35.4
Sensitive groups35.5–55.4
Unhealthy55.5–125.4
Very unhealthy125.5–225.4
Hazardous225.5+

All cities in the world, 2025 · Thailand now