6 June 2024

The COVID-19 crisis may have passed, but the threat from smog is back for the long term. Hazy skies are a sign that hazardous fine dust particles – which can be deadly – should not be taken for granted.

“We expect the smog to worsen in the rest of this year,” said Kasetsart University’s Assoc Prof Witsanu Attavanich, an expert in climate-change research and PM2.5 situation analysis.

Dr Witsanu explained that the amount of PM2.5 dust – tiny particles in the air measuring 2.5 microns or less in diameter – is now growing because stay-at-home COVID-19 control measures are being lifted.

“Most people no longer work from home,” he said. “Most students have returned to campus too”.

Sonthi Kotchawat, an independent expert on environmental health, notes that many kinds of activities have resumed in the post-pandemic period.

Back in 2019, the average amount of PM2.5 particles was as high as 59 micrograms per cubic meter (μg/m3) of air in Bangkok. The number of days when PM2.5 exceeded the safe limit of 50μg/m3 was 64.

The situation eased a little in 2020 when lockdown measures were imposed to control the spread of COVID-19. The average amount of PM2.5 dropped to around 46 micrograms, while the number of days on which dangerous levels were detected fell to 60.

Last year, when COVID-19 restrictions were relaxed somewhat, the number of days when PM2.5 rose above the safe limit edged up to 61.

3 main polluters

Witsanu said farming activity, combustion-engine vehicles, and industrial operations are the three main contributors to PM2.5 pollution. From November onward, farmers often burn their land to clear agricultural waste in preparation for the new growing season.

“Black exhaust fumes from vehicles are also responsible for air pollution. Thailand has postponed imposing Euro 5 emission standards from 2020 to 2024. Without that postponement, air pollution could have been significantly curbed,” he said.

There were 11.56 million registered vehicles in Bangkok alone this year, up from 10.9 million last year.

Witsanu added that many factories have now switched their machines back on round the clock, but the Department of Industrial Works has not yet released information on their pollutant emissions.

Smog to worsen in coming months

Witsanu said rain was a key factor in easing air pollution, and forecast the dry season would bring worsening air quality across Thailand. Normally, the transition between the wet season and dry season falls in October.

Smog will arrive in Greater Bangkok first before spreading to other parts of the country, he predicted.

“Smog started posing problems in November. It will peak in December or January,” he added.

He expects the Northeast to face heavy PM2.5 pollution from December to March, when farmers resort to agricultural burning. The region will very likely be affected by haze from neighboring Laos and Vietnam too.

“The North, meanwhile, will face a PM2.5 threat from January to April because of farm burning, forest fires, and smog from Myanmar.”

Can smog lead to a slow death?

Earlier this month, the public was shocked to learn that a 28-year-old medical lecturer had been diagnosed with terminal-stage lung cancer despite exercising regularly, taking plenty of rest, and not smoking.

The young doctor has lived in the northern province of Chiang Mai for more than 10 years, prompting many people to blame his cancer on smog. Chiang Mai is notorious for severe air pollution at certain times of the year.

The World Health Organization’s (WHO) International Agency for Research on Cancer has classified outdoor air pollution and specifically the particulate matter in polluted air as carcinogenic.

Last year, WHO lowered its safe limit for average levels of PM2.5 over the whole year from 10μg/m3 to 5μg/m3. It based the decision on solid scientific evidence that when PM2.5 rises above that level, the fatality rate soars. For a 24-hour period, WHO set the ceiling at 15μg/m3 micrograms.

Thailand’s standards on PM2.5

Thai authorities set a far higher safe limit, insisting that air quality is healthy if average PM2.5 does not rise higher than 50μg/m3 over 24 hours.

However, in line with global trends, Thailand’s PM2.5 standard is set to be tightened. From June 1next year, the 24-hour safe limit will fall to 37.5μg/m3.

But concern is growing over whether the country’s major polluters can adjust to help meet the new safe limit.

“I am not sure whether all parties in Thailand are ready to comply with this standard,” Sonthi commented.

Thai authorities’ response

The Center for Air Pollution Mitigation (CAPM) has now implemented seven measures to fight smog. These measures include early warnings for all areas, treating smog as a national agenda, upgrading fuel management, implementing a Fire Danger Rating System, pushing for international anti-smog mechanisms; and engaging all sectors in efforts to eradicate smog.

CAPM is also seeking to curb emissions at source, from factories, vehicles and other polluters. It is also setting up an air-quality data center, which will use CCTV to identify pollution hotspots and any outdoor fires in the area. When a fire is detected, Bangkok Metropolitan Administration (BMA) personnel will be deployed to extinguish it quickly.

The Disease Control Department, meanwhile, has nudged 22 hospitals in Greater Bangkok to investigate which diseases are linked with dust-particle pollution. To date, the research has covered 3,409 people with asthma and other respiratory problems. Fifteen diseases have been identified as being linked to air pollutants, information that gives relevant authorities more data to protect people from smog.

The Public Health Ministry has also set up 66 air-pollution clinics in 33 provinces across Thailand. Better still, as many as 78 medical facilities are providing online counseling for patients with illnesses related to air pollution.

In the capital, the BMA has set up five air-pollution clinics.

What does Thailand still lack?

Dr Chaicharn Pothirat, a medical lecturer at Chiang Mai University’s Faculty of Medicine, said the percentage of lung cancer patients who have never smoked is close to that of smokers.

“But in Thailand, we do not treat people suffering from pollution the same as smokers. In the United States, those exposed to air pollution are treated just like smokers, to monitor their cancer risks,” he explained.

Meanwhile, several provinces in Thailand have no devices to monitor air quality. Bangkok has more than 50 of the government’s 138 air quality monitors while some provinces do not even have one.

Greenpeace points out that people living in the Northeast know very little about the air quality in their hometowns due to a shortage of these devices.

By Thai PBS World