Fires continued ravaging forests in the north on Saturday, according to the Geo-Informatics and Space Technology Development Agency (GISTDA).
Satellite images charting the progress of large fires across Thailand yesterday morning showed the number of hot spots in the north has risen to 1,334 from 823 on Friday.
In total, there were 3,238 forest fires recorded nationwide.
The province with the highest number of large-scale blazes was Mae Hong Son in the north with 340, followed by Uthai Thani in the central region (209) and Tak (205) which is also in the north.
Meanwhile, the Pollution Control Department's air monitoring stations showed the overall level of PM2.5 in the Mae Hong Son province yesterday rose to 96 microgrammes per cubic metre (µg/m³), almost double the PCD's safe threshold of 50 µg/m³.
Another hard-hit area was Lampang province where fires continued to ravage national park and wildlife sanctuary areas.
Narongsak Osottanakorn, the Lampang provincial governor, said that despite the fires, levels of PM2.5 have remained normal, although he added that he expected them to rise again this week.
An official working in Doi Pha Mueang Wildlife Sanctuary in the province said the fires had wiped out 13 rai of forest in a single day, including seven rai of forest in conservation areas in Tham Pha Thai National Park.
Meanwhile, Monton Sudprasert, director-general of the Department of Disaster Prevention and Mitigation, said yesterday two helicopters deployed to tackle fires in inaccessible mountain areas in Lampang, Chiang Mai and Phrae have combated blazes across 5,550 rai of land since Jan 29.