A haze is expected to choke Bangkok and the upper parts of the country until Monday next week, as changing atmospheric patterns are trapping PM2.5 dust particles and transboundary pollution from Cambodia over Thailand, according to the Centre for Air Pollution Mitigation.
"Bangkok and some other parts of the country are now under threat from the transboundary haze caused by massive open burnings outside of the country," Theerapat Prayurasiddhi, CAPM member and permanent secretary of the Prime Minister's Office said on Tuesday.
According to him, the Pollution Control Department's (PCD) monitoring equipment has detected over 4,000 hotspots in Cambodia, and the department has already sent a letter to the Asean Secretariat in Jakarta, Indonesia, asking the bloc to look into them.
Over 10,000 hotspots are detected in the Lower Mekong region annually, as farmers engage in open burning to prepare their land for the harvest and re-planting of maize, sugar and rice, Mr Theerapat said.
Since the low-pressure system formed above Thailand several days ago, at least 26 provinces have reported unhealthy levels of the ultra-fine PM2.5 dust particles — with 24-hour averages hovering between 46-82 microgramme per cubic metre (µg/m³).
The PCD set the safe threshold for PM2.5 exposure at 50µg/m³.
Bangkok's air quality dropped on the first day of school reopening, with 67 out of the 73 air quality monitoring stations reporting higher than recommended PM2.5 readings. On Tuesday, PM2.5 levels in the city hovered between 52-82µg/m³.
To help combat the open burning of farm waste, the government is offering soft loans of up to 1.5 billion baht for sugarcane farmers to purchase industrial shredders and sugarcane harvesting vehicles.
A total of 895 hotspots were detected in Thailand since the start of the year, most of which were illegally lit in national forest reserves, as well as Sor Por Kor lands which were given to landless farmers to help them make ends meet.
