On Monday morning, hazardous levels of PM2.5 dust covered Bangkok and 23 provinces, mainly in the Central Plains.
The Geo-Informatics and Space Technology Development Agency (Gistda) reported at 6 a.m. that PM2.5 concentrations ranged from 37.6 to 50.6 micrograms per cubic metre (µg/m³) in Bangkok and the affected provinces. The government’s safe standard for PM2.5 is 37.5 µg/m³.
Samut Sakhon province recorded the highest level at 50.6 µg/m³.
Thick and harmful smog also affected areas like Pathum Thani, Nakhon Pathom, Bangkok, Ayutthaya, and Chon Buri.
In contrast, 12 provinces, including Mae Hong Son, Chiang Rai, and Phatthalung, enjoyed good air quality with PM2.5 levels between 8.9 and 14.4 µg/m³.
Other regions experienced either good or moderate air quality.
According to the Meteorological Department, the smog is caused by stagnant air conditions expected to persist until Wednesday.