Thai Airways International has cancelled flights between Chiang Mai and Mae Hong Son for safety reasons as dust haze continues to shroud the northern sky.
Soldiers in Mae Sai district in Chiang Rai near the border with Burma fight against bushfires that have caused serious air pollution in the area. Burmese troops also joined the operation yesterday. TEERAWAT KHAMTHITA
The national carrier made the decision as the dust clouds hang over the two provinces, creating some areas of zero visibility on the 35-minute flight, according to THAI staff.
The pollution situation, mainly caused by fires in forests and open fields, has become worse as winds have not been able to take the haze upward due to a new ridge of high pressure from China which has spread to northern Thailand over the weekend.
As a result, the haze is expected to blanket Chiang Mai until the end of the month, said Chiang Mai's deputy public health chief Surasing Wisarurat.
The province of more than 1.6 million has already been hit by dust clouds for 10 consecutive days.
Chiang Mai residents hope rain will relieve the situation. Many people suffer respiratory disorders because of the haze.
Officials have been forced to use water trucks to spray streets as well as using water sprinklers, officials said.
An average of 2,000 people are visiting public health clinics every day. For the past three weeks, more than 10,000 people have sought medical advice mainly for respiratory problems and allergic reactions, according to Chiang Mai public health office.
The dust haze is made up of tiny particles, better known as particulate matter (PM) 10 with sizes of less than 10 micrometres. These particles can easily enter human lungs.
In Mae Hong Son, the PM 10 level was measured at 244 microgrammes per cubic metre, or two times higher than a safety level of 120, while Lampang has suffered 29 days of PM 10 haze.
Surapol Lilawaropas, director for forest fire control, blamed villagers who set fires in forests and farmlands for the pollution.
Those who search for wild plants such as mushrooms need to burn the undergrowth to quicken growth while farmers simply cleared their lands with fire.
The number of bushfires increased sharply this year, Mr Surapol said. This month, fires have occurred on 2,257 rai of forest, compared with only 453 rai in the same period last year, he said.
The state has begun a campaign in a bid to halt people setting fire in open fields, but it seems to have have fallen on deaf ears.
"It's difficult to talk with them. Such practices are their way of life," Chiang Mai governor Wibul Sa-nguanpong said.