The Chiang Mai authorities in northern Thailand will hand out face masks to the public as the province struggles with dangerously high levels of air pollution caused by persistent forest fires.
The fires are an annual problem between the months of December and April, when farmers set light to their fields to clear the land ready for the next crop cycle.
The government has temporarily closed several national parks and wildlife sanctuaries in north and western regions because of the fires, and it is expected that cloud-seeding will be used from Saturday in some areas, Thai PBS reported.
Helicopters have dropped water on fires in Kanchanaburi in west Thailand but with little success because of the dry weather conditions.
In Chiang Mai, authorities sprayed water mist along the roads to reduce dust levels and collected leaves to reduce the likelihood of fires spreading.
Chiang Mai was at one point the worst city in the world for air pollution on Wednesday, according to a live ranking by a Swiss air quality company. IQAir said levels of PM2.5 particulate matter in the city’s air reached 117 micrograms per cubic metre by 11am – far higher than the World Health Organization’s annual guideline of 5µg/m³.
The public in Chiang Mai have been advised to avoid outdoor activities, to use N95 masks or air purifiers and to seek medical care if they experience symptoms of high air pollution. These include respiratory tract problems, as well as dermatitis or eye inflammation.
Some in the province, a tourist hotspot famous for its mountainous landscapes, fear the persistent annual haze could deter travellers from visiting. Pallop Saejiew, the president of Chiang Mai’s Tourism Industrial Council, told the Bangkok Post last weekend that companies running outdoor activities had been hit by a fall in demand.
Bangkok has also recorded dangerous levels of pollution over recent days and was ranked among the top 10 worst cities globally by IQAir, with PM2.5 levels reaching 94.2µg/m³.
The Ministry of Natural Resources and Environment said it expected high dust levels again on Thursday in Bangkok but that afterwards southern winds should help to clear particulate matter from the city’s air.
Northern provinces, however, would continue to have high levels of dust for another week, it predicted.
