Bangkok's air pollution exceeded health safety levels on five of the last eight days, brought on by still and stagnant air, the Pollution Control Department reported on Thursday.
The amount of fine particulates no more than 2.5 micrometres in diameter had exceeded the safety limit of 50 microgrammes per cubic metre of air these five days, Thaloengsak Phetsuwan, air and noise quality director of the department, said.
These stagnant conditions normally occurred for a short period in the capital during the seasonal transition from winter to summer, when there was little or no wind. This allowed pollution, mainly from vehicles, to accumulate in the air. It had the appearance of white or white-brown mist, he said.
In Bangkok the department took daily air quality measurements at five locations. Readings on Thursday showed the air was hazardous on Intarapitak Road in Thon Buri district, at 57 microgrammes.
When the level of fine particulates breaches the safe ceiling, people experience throat irritation and breathing difficulties. The tissue of organs in the respiratory system could be destroyed by long exposure to the unsafe air, Mr Thaloengsak said. He advised people to limit outdoor activities and wear a face mask.