Air pollution across the upper North remains at critical levels with authorities monitoring almost 400 active hotspots in Chiang Mai alone on Sunday. The air quality did not improve on Monday morning, with IQAir recording "very unhealthy" air quality and hazardous, ultra-fine PM2.5 dust levels at 170.1 microgrammes per cubic metre (μg/m³) at 10.30am in the so-called "Rose of the North".
A combination screenshot from https://aqicn.org/city/chiang-mai/ and https://www.iqair.com/thailand/chiang-mai at 10.30am on Monday.
According to the State of Global Air report for 2019, PM2.5 caused 23,800 premature deaths in Thailand in 2017. By comparison, the Covid-19 pandemic that has plunged the country into panic has so far killed seven people.
Government spokeswoman Narumon Pinyosinwat said fires have undoubtedly affected air quality, with 17 provinces in the North reporting an increase in levels of PM2.5 pollutants on Sunday.
Only Nakhon Sawan and Uthai Thani reported PM2.5 readings below the Pollution Control Department's "safe" threshold, set at 50 μg/m³ .
Chiang Dao district in Chiang Mai reported the highest PM2.5 reading in the North on Sunday at 360μg/m³.
Ms Narumon said the worsening pollution is caused by a combination of factors which include arson, drought and prevailing wind patterns which trap pollutants right above Thailand. Others say agribusiness has exacerbated the problem.
According to satellite data from the Geo-Informatics and Space Technology Development Agency (Gistda), as of Saturday, there were 3,809 hotspots in Thailand, 5,061 in Laos and 10,061 in Myanmar.
As of Sunday, 398 hotspots -- or almost 10% of the country's hotspots -- were found in Chiang Mai.
Most of the blazes were related to an ongoing bushfire in Doi Suthep-Pui National Park in Chiang Mai's Muang district, which suddenly raged out of control late on Saturday after burning for about a week.
Authorities deployed four helicopters to combat the blaze, while drones and paragliders were sent to help detect hotspots and suspicious activities among villagers, who have been blamed for starting the forest fires to clear land for agriculture.
A source said that after several fires near Hmong villages within the park and in nearby Hang Dong district were found to have been deliberately set, local villagers in the area have been instructed not to engage in slash-and-burn farming until April 30.