Bangkok governor Chadchart Sittipunt has told Bangkok Metropolitan Administration (BMA) staff to wear face masks when working outdoors to protect against PM2.5 pollution.

PM2.5 is fine-dust air pollution that poses health risks, especially for people with chronic lung disease.

Chadchart noted that the fine dust hit dangerous (red) levels in three districts – Prawet, Bang Na and Nong Khaem – on Wednesday, according to the PM2.5 alert system the BMA has launched with the Line messenger app.

PM2.5 was at the “caution” (orange) level in 19 other districts of the city.

The red level signals over 90 micrograms of PM2.5 dust per cubic metre of air (μg/m3), while orange signals over 75μg/m3.

Thailand’s safe limit of PM2.5 is 50μg/m3.

High pollution levels in Bangkok are expected to last until at least Saturday, due to a high-pressure weather system.

“These conditions could be a health risk for people working outdoors for prolonged periods such as road sweepers, garbage collectors, and sewage workers,” said the governor.

“The BMA therefore urges every employee to wear sanitary masks or N95 masks to protect themselves from PM2.5.”

The governor also ordered supervisors to monitor the health and working conditions of their staff closely. Anyone displaying symptoms of respiratory disease will be sent to BMA air pollution clinics equipped to treat respiratory diseases at five locations.

The clinics are located at BMA General Hospital, Taksin Hospital, Charoen Krung Pracharak Hospital, Ratchaphiphat Hospital, and Sirindhorn Hospital.

Chadchart also advised people in risk groups (small children, pregnant women, and seniors) to avoid or reduce outdoor activities and wear a face mask when leaving the house. Those who have chronic respiratory diseases should also keep their medicines handy at all times.

“If possible, try to work from home or reduce the use of personal vehicles by switching to public transport instead,” Chadchart said.

To get real-time reports of PM2.5 in the Bangkok area via the Line Alert account, simply add @linealert as a friend or click https://lin.ee/l40xtWN.

Alternatively, people can check the pollution status via www.airbkk.com or www.pr-bangkok.com.