Employers in the smoggy North and other areas are being advised to allow their employees to work from home whenever possible because of the high levels of PM2.5 dust in the air.
Public Health Minister Anutin Charnvirakul on Monday also advised people in regions where fine dust levels are unsafe to wear face masks to help avoid respiratory problems.
He said that since the beginning of the year about 1.4 million people had been treated for illnesses related to air pollution.
The ministry had opened emergency centres to cope with the situation. All hospitals had been instructed to be ready to take care of people affected by the toxic smog, he said.
Mr Anutin advised the private sector to arrange for their employees to work from home when possible to reduce traffic on the roads, which is a major cause of air pollution. The Ministry of Transport was expediting its plans to put electric buses into service and reduce emissions of exhaust fumes and carbon monoxide.
"The ministry's plans to have 4,800 electric buses operating, and 1,250 have already been put into service. The rest are being gradually delivered as ordered," Mr Anutin said.
The Pollution Control Department on Monday reported the average PM2.5 levels by region as follows -- 58-224 microgrammes per cubic metres (μg/m³) in the North; 28-81 μg/m³ in the Northeast; 28-64 μg/m³ in the Central Plain and the West; 29-58 μg/m³ in the East; and 15 - 37 μg/m³ in the South.
The Meteorological Department issued an advisory that a high-pressure system and moderate cold air was extending from China to cover the upper part of Thailand and the South China Sea. There would be summer storms in the North, Northeast and Central regions, including Greater Bangkok, and the East. Thunderstorms in these regions could bring gusting wind and hail, with possible lightning strikes.
Provinces likely to be affected:
On Monday - Mae Hong Son, Chiang Mai, Chiang Rai, Lam Phun, Lampang, Phayao, Nan, Phrae, Uttaradit, Tak, Sukhothai, Khamphaeng Phet, Phichit, Phitsanulok and Phetchabun in the North; Loei and Nong Khai in the Northeast; Kanchanaburi, Suphan Buri, Ayutthaya, Ratchaburi, Nakhon Pathom, Samut Sakhon, Samut Songkhram and Greater Bangkok in the Central; and Chachoengsao, Chon Buri, Rayong, Chon Buri and Trat in the East.
On Tuesday - Chanthaburi and Trat in the East.