Nineteen provinces in the North and the Northeast were shrouded with slightly unsafe levels of fine dust but no “red” levels of air pollution were detected nationwide on Tuesday afternoon.
The Geo-Informatics and Space Technology Development Agency reported on its website at 3pm Tuesday that the highest level of particulate matter 2.5 micrometres and less in diameter (PM2.5) was in the northern province of Mae Hong Son, at 47.6 microgrammes per cubic metre of air over the past 24 hours. The safe threshold is 37.5µg/m³.
Nineteen provinces including Mae Hong Son had orange (initially unsafe) levels of PM2.5, ranging from 37.9 to 47.6µg/m³.
The provinces were, in descending order: Mae Hong Son, Chiang Mai, Lamphun, Nong Khai, Nakhon Phanom, Udon Thani, Lampang, Bueng Kan, Loei, Phayao, Sakon Nakhon, Tak, Kalasin, Chiang Rai, Nong Bua Lam Phu, Nan, Roi Et, Chaiyaphum and Mukdahan.
The southern province of Krabi had the best air quality with a PM2.5 reading of just 12.1, followed by Samut Sakhon in the Central Plains with 20.0.
Seasonal air pollution from wildfires, agricultural burning and vehicle and factory emissions has been exacerbated this year by extremely hot and dry conditions.
On several occasions over the past few weeks, Chiang Mai in particular has had the unwelcome distinction of having the worst air in the world. Authorities there have come up with more measures to deal with the main contributing factors and deliver emergency assistance to any areas requiring it.
The map from Gistda shows good air quality in most parts of the country on Tuesday afternoon.