The Pollution Control Department warns thick fine dust will blanket Greater Bangkok on Jan 5-10 due to air stagnation.
Attapol Charoenchansa, director-general of the department, said that the levels of particulate matter 2.5microns and less in diameter (PM2.5) were safe nationwide at 7am on Jan 4.
PM2.5 levels ranged from 21 to 39 micrograms per cubic meter of air in 24 hours in Greater Bangkok. The safe threshold in the country was set at 50mcg.
Mr Attapol said PM2.5 would build up from Jan 5 to 10 due to air stagnation and the pollution would be relieved on Jan 11.