SmogRank / Episodes / Thailand
Bad-air episodes in Thailand
7 times since January 2023, many cities in Thailand had air at least twice as dirty as their usual for the time of year on the same days. The largest reached 53 cities: Central Thailand, March 2025.
2026
- North-western Thailand and Laos, April 202613 to 15 April 2026, 3 days8 cities219Ban Houakhoua
- North-western Thailand and Laos, April 20261 to 6 April 2026, 6 days8 cities223Ban Houakhoua
2025
- Northern Thailand, November and December 202530 November to 3 December 2025, 4 days22 cities64Mueang Nonthaburi
- Central Thailand, March 202520 to 29 March 2025, 10 days53 cities154Vientiane
- Western Thailand, February 202512 to 13 February 2025, 2 days17 cities88Samut Sakhon
- North-eastern Thailand, February 20251 to 3 February 2025, 3 days9 cities80Phetchaburi
- Central Thailand, January 202523 to 26 January 2025, 4 days50 cities117Khlong Luang
Each row: one bar per day, as tall as the number of cities counted that day and coloured by their median level; the number of cities; the highest daily reading and where. An episode is a run of days when many cities close to each other (four or more within 350 km on a day, 8 or more in all) each had a daily PM2.5 mean of at least 25 µg/m³ and at least 2 times their usual for that time of year. Found in our own measurements, not picked by hand. How we find episodes.