BMA enforces the drastic measure, LEZ, for the first time to ban six-wheeled vehicles from entering the inner areas of the city to try to curb the rise of PM2.5. Photo: Sayan Chuenudomsavad

IN PICTURES: Bangkok (still) in the Haze

As of Jan 24, 2025, the situation in the capital of Bangkok has worsened. The concentration levels of the toxic PM2.5 haze in most of its areas, 67, have increased beyond the 24-hr average hazardous level set at 75.1 micrograms per cubic metre (µg/m3), being registered as “Red” meaning the dust affects health. There are only three areas left as “Orange”, meaning the toxic dust starts to affect health with the concentration levels recorded between 37.6-75 (µg/m3). On average, the concentration level of the toxic PM2.5 in the city today was registered at 88.4 (µg/m3), according to the Bangkok Metropolitan Administration (BMA).

Since the beginning of the week, Bangkok has plunged into the toxic PM2.5 haze, with the concentration levels increasing beyond the safe limit in all 50 districts, on Monday and Tuesday. This prompted the BMA to start to enforce some measures to cope with the situation. 

At first, it declared the voluntary Work From Home measure for Monday and Tuesday before the measure was extended to cover the whole week. But that seems not to be enough as the toxic dust levels have escalated. 

Bangkok Governor Dr. Chadchart SIttipunt seems to have realised the situation. He came up with the drastic measure for the first time, which is the declaration of the Low Emission Zone (LEZ) to ban six-wheeled vehicles without pre-registration under the BMA’s Green List to enter the inner areas of the city.

They are known as being among the prime sources of the dust in the city due to their aged old engines with incomplete combustion. A number of schools, over 350 so far, have also been temporarily closed to avoid the impacts of the toxic dust.

As it has turned out, the concentration levels of the toxic dust have increased on the contrary. The prospect does not look good as well because the air ventilation will remain poor alongside the inversion within the next few days. 

This is the first time in this year that Bangkok has faced such a haze crisis. But it’s not the first time that this city has faced the toxic PM2.5 haze. Dr. Chadchart admitted that the sources of the origin of the haze still persist, reflecting the limitation the city has in order to address the crisis.

As ever explained by the Governor in 2023, the prime sources of PM2.5 pollution in the city principally come from incomplete combustion of car engines and biomass burning, both from inside and outside the country. 

Under normal circumstances, incomplete combustion of vehicles in the city could cause PM2.5 concentration levels to rise up to 30 µg/m³. If the weather is closed, the dust levels could rise up to 60 µg/m³. This could be exacerbated by biomass burning, which could cause the PM2.5 dust levels to rise up to 90 µg/m³, according to the Governor.

These facts still hold true up until today as being confirmed by the latest monitoring by Kasetsart University’s Environmental Studies Faculty, which helps the BMA to identify the sources of origin of the dust in the capital.

“It’s not just a problem of Bangkok. The haze covers several provinces and regions_from our peripheries to the Central Plains, the East, and others.

“I just hope it will improve soon,” said the Bangkok Governor, citing the improvement of the air ventilation in the next few days as earlier projected.

The BMA installs water-spraying devices beneath skywalks to ease PM2.5 haze during heavy traffic.
Photo: Sayan Chuenudomsavad
Concerned authorities try to give warnings about PM2.5 to passengers on the road.
Photo: Sayan Chuenudomsavad
Traffic police officers are instructed to step up their inspection over old vehicles with incomplete combustion in the city.
Photo: Sayan Chuenudomsavad
Authorities from the Pollution Control Department help traffic police officers inspect old vehicles with incomplete combustion.
Photo: Sayan Chuenudomsavad
Exhaust fumes discharged from a vehicle with incomplete combustion during the inspection by concerned authorities.
Photo: Sayan Chuenudomsavad
Exhaust fumes discharged from a vehicle with incomplete combustion during the inspection by concerned authorities.
Photo: Sayan Chuenudomsavad
A smoke check device used to gauge whether the exhaust fumes released from a vehicle are beyond the safe limit.
Photo: Sayan Chuenudomsavad
A vehicle with exhaust fumes beyond the safe limit will receive a temporary ban on the road for 30 days or until its owner fixes the engine.
Photo: Sayan Chuenudomsavad
A permanent ban for vehicles beyond repair.
Photo: Sayan Chuenudomsavad
Bangkokians have been enduring the spike of PM2.5 to health hazardous levels for the whole week.
Photo: Sayan Chuenudomsavad
The situation will linger in town for the next few days due to poor air ventilation and invesion.
Photo: Sayan Chuenudomsavad