On Wednesday morning, only seven of Thailand’s 77 provinces experienced safe air quality, with the majority, including the capital, engulfed in hazardous levels of ultrafine dust. The Geo-Informatics and Space Technology Development Agency (Gistda) reported that as of 8 AM, 39 provinces were significantly affected, registering “red” hazardous levels of particulate matter measuring 2.5 micrometres or smaller (PM2.5).
PM2.5 concentrations ranged from 76.5 to 143.1 micrograms per cubic metre over the past 24 hours, peaking in Samut Sakhon province. Pathum Thani recorded 133.2 µg/m³, followed by Bangkok at 129.4 µg/m³, Nonthaburi at 128.6 µg/m³, and Ayutthaya at 125 µg/m³.
Provinces facing hazardous smog levels, listed in descending order, include Nakhon Pathom, Samut Prakan, Ang Thong, Sing Buri, Saraburi, Lop Buri, Samut Songkhram, Ratchaburi, Phetchaburi, Suphan Buri, Chai Nat, Uthai Thani, Nakhon Sawan, Chachoengsao, Nakhon Ratchasima, Kanchanaburi, Chaiyaphum, Prachin Buri, Phetchabun, Phichit, Nakhon Nayok, Sa Kaeo, Maha Sarakham, Chon Buri, Khon Kaen, Kamphaeng Phet, Nong Bua Lam Phu, Nong Khai, Phitsanulok, Udon Thani, Prachuap Khiri Khan, Rayong, Loei, and Buri Ram.
The government has set the safe PM2.5 threshold at 37.5 µg/m³.
Meanwhile, 31 provinces recorded “orange” levels of PM2.5, indicating that ultrafine dust is beginning to impact health, with concentrations ranging from 41.7 to 73.4 µg/m³.
These provinces include Tak, Kalasin, Chanthaburi, Surin, Sakon Nakhon, Mukdahan, Roi Et, Ubon Ratchathani, Sukhothai, Si Sa Ket, Nakhon Phanom, Phatthalung, Yala, Trang, Pattani, Narathiwat, Satun, Phuket, Songkhla, Yasothon, Amnat Charoen, Uttaradit, Trat, Bueng Kan, Krabi, Nan, Lamphun, Phrae, Nakhon Si Thammarat, Phang Nga, and Lampang.
Only a few provinces recorded safe PM2.5 levels ranging from 21.2 to 36.4 µg/m³—these include Phayao, Ranong, Chiang Rai, Surat Thani, Chumphon, Chiang Mai, and Mae Hong Son.
