Air pollution in Thailand’s Bangkok forces more than 350 schools to close

More than 350 schools in Bangkok have been forced to close due to air pollution, authorities in Thailand’s capital have said.

Since midweek, the Thai capital’s air quality has been deteriorating, with city officials announcing plans to close schools and directing residents to work from home after the air quality index (AQI) reached 159, according to IQAir, a partner of the UN Environment Programme.

Additionally, it’s prohibited to enter certain areas of the city with six-wheel trucks.

An AQI reading above 100 is considered unhealthy, while a reading above 200 is rated very unhealthy.

On Friday morning, when authorities announced the closure of about 100 additional schools, the AQI stood at 185.

As of 11am local time, Bangkok ranked as the eighth-most polluted city in the world, behind Dhaka, Lahore, Kathmandu, Karachi, Delhi, Mumbai and Ho Chi Minh City, according to IQAir.

While hundreds of schools remain closed, only about 100, 000 of Bangkok’s more than 10 million residents have signed up for a voluntary work-from-home scheme, according to the AFP news agency.

The increase in pollution was caused by the seasonal burning of crops, of vehicles, and of trash, according to Bangkok Governor Chadchart Sittipunt.

The AQI index, which was developed by the United States Environmental Protection Agency, measures ground-level ozone, particle pollution including PM2.5 and PM10, carbon monoxide, sulphur dioxide and nitrogen dioxide.

Much of Bangkok’s pollution this week was caused by a high concentration of PM2.5, cancer-causing microparticles. The city’s PM2.5 levels hit 108 micrograms per cubic metre on Friday morning, 21.6 times the World Health Organization’s annual guideline.

Pollution levels are expected to subside over the weekend, reaching 71 by Monday, according to a forecast by IQAir.