BANGKOK, THAILAND – Dangerous PM2.5 fine dust levels blanketed Bangkok and 58 of Thailand’s 76 provinces on Sunday afternoon, with the highest readings in the northern province of Chiang Rai.
Gistda reports widespread pollution
According to the Geo-Informatics and Space Technology Development Agency (Gistda), air in Bangkok and 58 provinces was at an unsafe PM2.5 level at around 3 p.m. on Sunday. The agency said the pollution posed a health risk across much of the country.
Measured PM2.5 concentrations ranged from 38.2 to 96.2 micrograms per cubic metre (µg/m³). All values were above the national threshold of 37.5 µg/m³ set by the government.
“Red” in ten provinces: peak in Chiang Rai
Gistda reported the highest level in Chiang Rai, in the far north, at 96.2 µg/m³. This was classified as “red” and therefore as seriously harmful to health.
In total, ten provinces were listed with “red” PM2.5 readings. Eight of them lay in the north and two in the northeast.
Red PM2.5 levels: affected provinces
After Chiang Rai, the highest values were recorded in Phayao (92.1), Nan (85.8), Phrae (83.8), Lampang (83.5), Chiang Mai (81.7), Mae Hong Son (78.6) and Uttaradit (75.7), all in the north. These readings all fell within the seriously harmful “red” range.
In the northeast, Bueng Kan (77.9) and Nong Khai (77.7) were also in the red zone. Gistda listed these provinces in its ranking of measured values.
“Orange” in Bangkok and 48 other provinces
Bangkok and 48 provinces in the north, northeast and central plain registered “orange” PM2.5 levels, Gistda stated. These levels were considered to mark the beginning of health-threatening conditions.
The “orange” readings ranged from 38.2 to 73.3 µg/m³. They included Bangkok as well as numerous provinces from Phichit and Lamphun to Chon Buri and Phetchaburi.
Yellow levels on the coast: five provinces with moderate air quality
Moderate “yellow” air quality was measured in five coastal provinces: Chanthaburi (37.5), Prachuap Khiri Khan (36.6), Trat (36.2), Rayong (34) and Pattani (25.1). These areas showed lower PM2.5 values than many inland regions.
According to Gistda, these readings were below or around the national threshold of 37.5 µg/m³ for PM2.5. They were therefore classified as moderate rather than clearly unhealthy.
Good air in the south: 13 provinces in the green zone
In 13 southern provinces, Gistda reported “green” PM2.5 readings and thus good air quality. Values there ranged from 21.8 to 24.7 µg/m³.
The provinces named were Phuket, Narathiwat, Satun, Krabi, Yala, Phatthalung, Songkhla, Phangnga, Nakhon Si Thammarat, Trang, Ranong, Chumphon and Surat Thani. These areas were far less affected than the northern and northeastern regions.
Colour map shows PM2.5 situation at 3 p.m.
Gistda published a colour-coded map showing PM2.5 levels across Thailand at 3 p.m. on Sunday. The visualisation illustrated the distribution of pollution nationwide.
The map made clear that northern areas, parts of the northeast and sections of the central plain were more heavily affected than many southern provinces. Large parts of the south remained in the green zone while the north was dominated by red and orange areas.