Air pollution in Phayao and Lamphun has worsened, with the amount of small particulate matter soaring well above the recognised safe level.
However, the latest air-quality checks yesterday showed PM10 had reached 172.1 micrograms in Phayao.
In Lamphun, the situation was even more serious, with PM10 touching 185.5 micrograms.
"The smog problem has been serious in Phayao since mid-February," Suwit Khattiwong said in his capacity as the head of Environmental Office Region 2, which covers Lamphang, Phrae, Phayao and Sukhothai.
Suwit said air-quality monitoring equipment had been installed in Phayao for the first time this year.
He believes the locals' way of life is one of the main causes of the smog problem in the northern province, as farmers set fires to get rid of leaves and garbage as well as to scare mosquitoes away from their livestock.
"Now, we are calling on local administrative organisations for help," Suwit said.
He added that awareness campaigns would be a major tool in persuading locals to stop harming the environment and their health.
"We will try to highlight the dangers of their actions," he said.
Anusit Methawararak, who heads the Phayao Natural Resource and Environment Office, said air pollution in the province looked set to reach its worst level in years.
Chiang Mai University researcher Assoc Prof Duangchan Arpawatcharut said human activities were the main causes of air pollution, especially farmers deciding to clear land by setting fires.
Mae Hong Son Natural Resources and Environment Office director Thakorn Lomsattaporn said forest fires and smog had damaged tourism in the popular town of Pai.
"Clearly, the number of tourists has dropped in the face of the smog," he said.
