Expert assuages concerns over sulphur smell in Bangkok caused by air stillness
An environment expert said that the smell of sulphur in Bangkok on Wednesday night, which led to panic in some people, was not hazardous to health and was caused mainly by heavy air.
In a Facebook post on Thursday, Sonthi Kachawat explained the reasons for the foul sulphur smell experienced by many Bangkok residents.
Some people panicked as Bangkok has been hit by high levels of PM2.5 ultrafine dust for many days.
Sonthi explained in the post that the smell followed heavy rains in many parts of Bangkok in the morning and in the afternoon.
When night fell, he said there was high humidity in the air, which had followed many days of hot weather in the capital.
He said the high pressure that came after the several days of low pressure had brought the rains and the heavy air, or air stillness.
With the air stillness, the PM2.5 particles, sulphur particles and carbon dioxide from car engines, burning of weeds or farm by-products and smoke from factories in Bangkok and surrounding provinces floated to accumulate in the air layer of the earth’s atmosphere.
He said these particles, especially carbon dioxide, reacted with oxygen, causing sulphur trioxide.
The accumulated sulphur trioxide and carbon dioxide had further caused sulphur dioxide and acid so Bangkokians felt irritation in their eyes and noses and they could sense a burning smell.
Sonthi assured Bangkokians that the level of sulphur dioxide was diluted and not dangerous and the situation would improve once the wind started blowing.
Aticharn Cherngchavano, an influencer better known as Ooh Spin 9, posted on his X microblogging account that the burning smell was very strong and he had used a gadget to measure the PM2.5 level at his balcony at 164 micrograms per cubic metre of air (μg/m3).
The government regards PM2.5 above 37.5 μg/m3 as hazardous to health.
At 11pm on Wednesday, the Geo-Informatics and Space Technology Development Agency reported very high levels of PM2.5 in many districts of Bangkok including:
Don Mueang - 143.5 μg/m3
Lak Si - 143 μg/m3
Bang Sue - 139 μg/m3
Chatuchak - 128.1 μg/m3
Phayathai - 127 μg/m3
Ratchathewi - 122 μg/m3
Bang Plad - 121.4 μg/m3
Dusit - 121.3 μg/m3
Meawhile, Pornphan Wikitseth, an adviser to the Bangkok governor, said the high levels of PM2.5 on Wednesday night was caused mostly by high humidity that caused certain kinds of gases in the air to reactivate and cause more PM2.5 ultrafine particles.
She added that the Bangkok Metropolitan Administration had also detected several burning spots in provinces around the capital.
