Gistda reported at 3pm that unsafe levels of particulate matter 2.5 micrometres and less in diameter (PM2.5) ranged from 38.2 to 96.2 microgrammes per cubic metre (µg/m³) of air in Bangkok and 58 provinces. The government-set safe threshold for PM2.5 is 37.5µg/m³, reports the Bangkok Post.
The highest level, a “red” 96.2µg/m³, seriously harmful to health, was recorded in the northernmost province of Chiang Rai, one 10 provinces with red levels of PM2.5 - eight of them in the North.
After Chiang Rai, red levels of PM2.5 were, in descending order, 92.1µg/m³ in Phayao, 85.8 in Nan, 83.8 in Phrae, 83.5 in Lampang, 81.7 in Chiang Mai, 78.6 in Mae Hong Son, 77.9 in Bueng Kan (Northeast), 77.7 in Nong Khai (Northeast) and 75.7 in Uttaradit.
Bangkok and 48 provinces in the North, the Northeast and the Central Plain were blanketed with orange levels (starting to harm health) of PM2.5 ranging from 38.2 to 73.3µg/m³.
In descending order, those PM2.5 levels were in Phichit, Lamphun, Loei, Sukhothai, Udon Thani, Nakhon Phanom, Nong Bua Lam Phu, Chai Nat, Sakon Nakhon, Phitsanulok, Sing Buri, Nakhon Sawan, Kamphaeng Phet, Phetchabun, Khon Kaen, Chaiyaphum, Tak, Mukdahan, Kalasin, Maha Sarakham, Uthai Thani, Suphan Buri, Roi Et, Nakhon Nayok, Lop Buri, Ang Thong, Ubon Ratchathani, Kanchanaburi, Nakhon Ratchasima, Yasothon, Si Sa Ket, Amnat Charoen, Buri Ram, Surin, Ayutthaya, Prachin Buri, Pathum Thani, Saraburi, Nonthaburi, Chachoengsao, Bangkok, Samut Songkhram, Sa Kaeo, Nakhon Pathom, Samut Prakan, Ratchaburi, Samut Sakhon, Phetchaburi and Chon Buri.
Moderate air quality was detected in five seaside provinces with yellow levels of PM2.5, namely Chanthaburi (37.5), Prachuap Khiri Khan (36.6), Trat (36.2), Rayong (34) and Pattani (25.1).
Thirteen southern provinces had good air quality with green PM2.5 levels ranging from 21.8 to 24.7µg/m³. In descending order of the ultrafine levels, they were Phuket, Narathiwat, Satun, Krabi, Yala, Phatthalung, Songkhla, Phangnga, Nakhon Si Thammarat, Trang, Ranong, Chumphon and Surat Thani.