Royally sponsored 'Jit Arsa' volunteers from the 2nd Cavalry Division in Bangkok give away masks to commuters passing Queen Sirikit National Convention Centre on Ratchadaphisek Road amid concerns over PM2.5 levels and the air pollution crisis. (Photo by Pattarapong Chatpattarasill)

More than 8,000 vehicles have been pulled over this month for belching black exhaust fumes in Bangkok, according to Metropolitan Police Bureau deputy commissioner Chirasan Kaewsaeng-ake.

Pol Maj Gen Chirasan told a press briefing on Friday that 8,284 vehicles were stopped for emitting choking black fumes at 33 checkpoints around the city in January.

The government blames much of the air pollution affecting Bangkok and the provinces on vehicle emissions.

The number of vehicles stopped was a significant rise on the 7,000 vehicles stopped and banned in December, the deputy commissioner said.

Of this month's number, 60% were large vehicles such as buses and trucks.

He said the 33 checkpoints are each manned by 7-10 police and Department of Land Transport officials with special equipment to measure pollutants being emitted by passing vehicles

"Offending vehicles are logged and marked with stickers, while the owners are given a month to fix the problem," he said.

"Officials will follow each case up using contact information and licence plate numbers and if owners fail to heed the warning their cars will be impounded," Pol Maj Gen Chirasan added.

Silapasuai Rawisaengsun, the permanent city clerk, said yesterday that the Bangkok Metropolitan Administration (BMA) has obtained four mobile air purifiers from the Rajaprajanugroh foundation under royal patronage and located them in the Phaya Thai and Rajavithi areas.

She said the purifiers can filter 2.2 cubic metres of air a second and release air of 85-90% purity.

Meanwhile, air quality around the city improved yesterday with Wang Thonglang the only district with fine particulate matter exceeding the recognised safety level.

Deputy Minister of Public Health, Satit Pitutecha, tried to allay pollution fears, saying the dust does not cause much damage to health and has affected very few people. Nonetheless, he said the ministry is offering advice on how to deal with health risks.