CHIANG MAI: The concentration of airborne ultra-fine dust particles in several northern provinces soared beyond safe limits on Wednesday, as hundreds of active fire hotspots were detected in the region.
Chiang Mai, in particular, experienced a massive drop in air quality yesterday, with levels of both the ultrafine PM2.5 pollutants and the larger, PM10 dust particles hitting levels considered to be unhealthy -- especially for younger children, the elderly, pregnant women and individuals with underlying respiratory and/or cardiovascular diseases.
Due to the worsening haze, residents have been advised to avoid all outdoor activities, a local source said.
According to readings from air quality monitoring station in tambon Chang Khoeng in Mae Chaem district, PM2.5 levels in the area reached as high as 91 microgrammes per cubic metre (µg/m³), while the concentration of PM10 pollutants peaked at 131µg/m³.
Based on the data reported by air monitoring stations in 17 northern provinces, PM2.5 levels in the region hovered between 32-90µg/m³, while PM10 concentrations ranged between 48-107µg/m³.
Meanwhile, Chiang Mai's command centre for wildfires and PM2.5 prevention said that as of 2am yesterday, at least 666 wildfire hotspots have been detected across the North -- 116 of which were found around Chiang Mai.
Mae Hong Son, however, had the most hotspots, with 186 detected in total, the centre said, adding most of the fires were in protected and reserve forests.
Of the 666 hotspots, 387 were in protected forest areas, 240 in reserve forests, while 19 were found in agricultural land reform zones, according to the centre.
Maj Gen Thanatphon Kosaisewi, deputy 3rd Army chief in his capacity as the deputy chief of the 3rd Army's wildfire and haze control command, said since their firefighting operation began on Sunday, 84,000 litres of water, transported in 42 helicopter trips, have been duumped on fires in the area.
Separately, Suchat Saelinwong, a firefighter with Khun Tan National Park who was hit by a moving train while combatting a blaze in Mae Tan Noi village in Lampang's Hang Chat district on Monday succumbed to his injuries yesterday.