Forty-eight provinces were blanketed with hazardous levels of PM2.5 on Monday morning and 11 provinces, mostly in the North, faced red levels of pollution with Chiang Mai suffering the most.
The Geo-Informatics and Space Technology Development Agency reported at 10am on Monday that the highest level of particulate matter 2.5 micrometres and less in diameter (PM2.5) was detected in the northern province of Chiang Mai, at 125.3 microgrammes per cubic metre of air over the past 24 hours. The government-set safe threshold is 37.5µg/m³.
Chiang Mai was among 11 provinces, mostly in the North, blanketed with red (seriously harmful) levels of PM2.5.
Second to Chiang Mai was Lamphun wih 117.3µg/m³ of PM2.5, followed by Mae Hong Son (114.9), Chiang Rai (113.5), Lampang (111.9), Phayao (110.8), Tak (100.7), Phrae (95.2), Nan (93.5), Uttaradit (77.8) and Ubon Ratchathani (76.2).
Thirty-seven provinces in the Central Plain and the Northeast faced orange (slightly harmful) levels of PM2.5.
They were Loei, Kamphaeng Phet, Phetchabun, Sukhothai, Nong Bua Lam Phu, Amnat Charoen, Kanchanaburi, Phitsanulok, Udon Thani, Nong Khai, Chaiyaphum, Si Sa Ket, Nakhon Phanom, Mukdahan, Sakon Nakhon, Uthai Thani, Yasothon, Khon Kaen, Kalasin, Nakhon Sawan, Bueng Kan, Phichit, Roi Et, Lop Buri, Sing Buri, Suphan Buri, Chai Nat, Nakhon Ratchasima, Maha Sarakham, Surin, Saraburi, Ratchaburi, Phetchaburi, Ang Thong, Ayutthaya, Prachuap Khiri Khan and Nakhon Pathom.
PM2.5 levels were considered safe in Bangkok and nearby provinces, some eastern provinces and southern provinces.