Thailand’s safety limit is 50 μg/m3. High levels of PM2.5 pose health risks, especially for people with chronic lung disease.
The Thai Meteorological Department (TMD) forecasts levels of PM2.5 – particles less than 2.5 micrometres in diameter – will rise across much of Thailand through Friday as the fine-dust pollution accumulates in stagnant air.
The government has advised people to wear face masks outdoors and consider working from home on Thursday and Friday.
Website iqair.com reported Bangkok’s air quality index (AQI) at 198 as of 9am on Thursday, making it the third-most polluted city in the world.
The Thai capital is behind only Mumbai in India (AQI 207) and Pakistan's Lahore (202).
The smog eased on Friday, with iqair.com registering an air quality index of 102 for Bangkok as of 9am.
The TMD forecasts air pollution in the capital will reduce on Saturday with the arrival of stronger winds to disperse the smog.