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REPORT: Let’s nail down SMOG CAUSES

Jan 18. 2019
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THE SMOG that’s been gagging Bangkok is a combination of multiple elements and understanding each one is crucial to finding a long-term solution, say experts.

The capital has been blanketed much of the time in a dense smog of fine dust particles known as PM2.5 since the New Year began, posing a threat to public health as well as to city tourism and the economy. 

Chulalongkorn University and Greenpeace have cited as the main causes vehicle exhaust, emissions from small-scale power plants and factories, open burning and climate factors.

They stressed that a full understanding of each pollution source and its relation to the overall situation is essential in devising long-term mitigation measures and ending the annual winter cycle of chronic air pollution.

Assoc Professor Sirima Panyametheekul, a lecturer in environmental engineering at Chulalongkorn, said that, even though Bangkok’s pollution comes from diverse sources and no academic study had yet clearly defined them or their relative ratio, there was no doubt that heavy traffic was the main contributor.

Sirima pointed out the air quality improved dramatically during the long New Year holiday, when many residents left the city to travel upcountry. As soon as vehicles were again jamming city streets after the holiday, the smog returned.

However, she said, the main reason the air quality worsened to a critical level each winter was the weather.

“The number of cars on the roads is basically unchanged throughout the year, while the air pollution peaks every January and February. So it can be concluded that calm winds at this time of year help the air pollution accumulate to a very harmful level,” she explained.

A boom in the construction of small-scale biomass power plants and waste-to-energy plants across the Central region and the East was another prominent factor, said Kulyos Audomvongseree, director of Chulalongkorn’s Energy Research Institute.

“Many people suspect large coal-fired and gas-fired power plants to be the main polluters behind the problem in Bangkok, but my studies indicate otherwise. These large power plants are normally equipped with efficient pollutant-trapping systems, so they emit only relatively small amounts of PM2.5,” Kulyos said.

He said the small plants burning solid waste and 

 biomass were actually emitting larger proportions of PM2.5 because they were too small to justify a costly investment in hi-tech pollution filters. Meanwhile the government is promoting development in East and Central Thailand and environmental regulations were weaker for smaller plants, he said.

A man tending to a street food stall wears a protective mask as bad air pollution continues to affect Bangkok. // EPA-EFE PHOTO

The Chulalongkorn academics stressed that further studies were needed to clearly identify the sources of Bangkok’s air pollution, saying the most effective way to control pollution was to tackle the problem at its sources.

Assoc Professor Manoj Lohatepanont, director of Chulalongkorn’s Transportation Institute, said that, since the climate cannot be controlled, long-term pollution-mitigation strategies involving every stakeholder were required.

Manoj suggested that Bangkok authorities create more green areas and encourage walking and bicycling.

“We should make our city friendly to pedestrians and cyclists and increase the quality and coverage of our mass-transit system, because walking and biking are the most environmentally friendly ways to get around the city,” he said.

“This transition needs a long-term strategy and a strong commitment from the authorities. Lowering the traffic volume would improve the air quality.”

Greenpeace Thailand country director Tara Buakamsri said some of the polution afflicting Bangkok was being carried on the wind from Cambodia, so its smog problem was in part an issue of transboundary haze.

“Asean Specialised Meteorological Centre and National Oceanic and Atmospheric Administration satellites have detected a very dense cluster of hotspots from open burning in the north and northeast of Cambodia in recent weeks, and easterly winds carry the smoke straight towards Thailand,” Tara said.

“The large-scale burning in the northern Cambodia is closely associated with the very high deforestation rate and rapid expansion of monoculture farming in that region in recent years.”

Thailand is this year chairing the Association of Southeast Asian Nations, Tara noted, so it has the opportunity to raise the issue and encourage fellow member-states, including Cambodia, to work together on resolving the issue of transboundary pollution.

“Asean doesn’t typically consider environmental issues a top priority, but the region is now facing more intense extreme weather and natural disasters, so now is the time for us to take environmental problems seriously,” he said.


REPORT: Diesel combustion drives this PM2.5 mess, said PCD latest study

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