Fine dust pollution dropped to safe levels in greater Bangkok on Thursday as a high pressure system moved out of Thailand and southeasterly winds brought rain to northen regions, according to the Pollution Control Department.
Director-general Pralong Damrongthai said on Thursday morning that levels of particulate matter 2.5 micrometres and less in diameter (PM2.5) were measured at 13-43 microgrammes per cubic metre of air in Bangkok and adjacent provinces over the previous 24 hours. The safe threshold is set at 50mcg in Thailand.
PM2.5 was measured 13mcg in Muang district of Samut Prakan province and 43mcg beside Charan Sanitwong Road in Bangkok's Bang Phlad district.
As the high pressure system moved out of the country, southeasterly winds were bringing humidity from the South China Sea and the Gulf of Thailand to the Northeast, the lower North, the East and the Central Plains, Mr Pralong said.
Consequently, rain in the upper regions of the country reduced the accumulation of fine dust in greater Bangkok, he said.
Another high pressure system from China is forecast to cover the Northeast from Friday to next Tuesday.