Foreign Minister Don Pramudwinai said Asean ministers have been discussing the issue of air pollution.
He said the problem of haze and small particles of dust in the North has existed for many years. However, the problem is more serious this year for many reasons.
"We have to solve the problems by putting out the fires and preventing any more burning. Anyone who starts fires must face harsh penalties," he said, adding that neighbouring countries have been informed about the severity of air pollution domestically and have agreed to help each other curb contributing emissions.
In the northern province of Phayao, Phusang National Park chief, Bantom Somsuwan, said firefighters from the province as well as those from Chiang Rai are attempting to put out wildfires along the Thai-Lao border. Round the clock patrols on Wednesday and Thursday resulted in a reduction in the number of fires and better air quality, he said.
At 3pm yesterday, the PM2.5 level in Phayao's Muang district was reported at 98 microgrammes per cubic metre (µg/m³) and PM10 at 125 µg/m³.
Meanwhile, in Nan yesterday, the level of air pollution has fallen slightly. PM10 downtown was at 91 µg/m³ and PM2.5 at 58 µg/m³, both a reduction on levels recorded on Thursday, according to a source.
Even so, PM2.5 in the area still exceeded Thailand's safety level of 50 µg/m³ and the World Health Organisation's hazardous level of 25 µg/m³.
On Monday, PM2.5 levels in Chiang Mai, Chiang Rai and Mae Hong Son soared to 300-500 µg/m³.
Prime Minister Prayut Chan-o-cha on Tuesday visited Chiang Mai and ordered the mobilisation of firefighting personnel and volunteers to douse bush fires in the North.
The premier said authorities must try to improve the haze situation within a week.
