December 15, 2023
CHIANG RAI – Mae Sai, the northernmost district of northern Thailand’s Chiang Rai province, is a major border crossing with Myanmar, famed for its lush hills. Doi Nang Non, which means “Mountain of the Sleeping Lady” in Thai, is one of the area’s most notable mountains.
Apart from being a tourist attraction, Doi Nang Non also acts as an air quality indicator for the students of Banpafae-nongor-sansaimoon School in Mae Sai.
“The mountain is just a few kilometers away from the school and we taught students a simple way of recognizing air pollution levels using visibility between the school and Doi Nang Non,” said Nion Sirimongkollertkul, from the Faculty of Engineering at the Rajamangala University of Technology Lanna in Chiang Rai.
In April last year, Chiang Mai — northern Thailand’s cultural and tourist hub, and home to about 128,000 people — ranked as the world’s most polluted city ahead of hot spots such as Lahore in Pakistan and Teheran in Iran, according to the Swiss air quality firm IQAir
“If they can barely see the mountain, the air quality is dangerous to human health and they should avoid staying outdoors,” said Nion, who has studied air pollution for more than a decade.
Nion first became aware of air pollution in Thailand and its impact 16 years ago when she was pregnant. In the past decade, toxic haze pollution has become northern Thailand’s most acute environmental disaster.
A haze is a light mist, caused by particles of water or dust in the air, which prevents one from seeing distant objects clearly.
The period between February and April is now referred to as “haze season”.
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In April last year, Chiang Mai — northern Thailand’s cultural and tourist hub, and home to about 128,000 people — ranked as the world’s most polluted city ahead of hot spots such as Lahore in Pakistan and Teheran in Iran, according to the Swiss air quality firm IQAir.
“There are multiple factors attributed to smog, including climate change and industrial emissions. But the biggest sources of toxic haze are forest fires and agricultural burning,” Nion said.
“To save on costs, farmers remove the undergrowth by burning it for cultivating new crops such as sugar cane, maize, and even rice.”
Somporn Chantara, a chemistry professor at Chiang Mai University, said that the dominance of PM2.5 — health-damaging particulate matter with a diameter of 2.5 micrometers or less — gives northern Thailand’s smog its characteristic smoky smell.
Most of the smog in northern Thailand originates from agricultural burning in neighboring countries, including Myanmar and Laos, especially in the border areas of these countries, according to Nion.
“Taking Mae Sai as an example, it has been suffering severely from the haze even though agricultural burning has been strictly controlled in recent years. It’s not a problem that can be solved from a single side,” she added.
Tongsuk Riyakad, a grade-six teacher at Banpafae-nongor-sansaimoon School, said the annual health checks for the nearly 200 students indicated that more incidents of allergy have been witnessed in recent years.
Last year alone, 30 students were reported to have allergy symptoms that were related to air pollution, such as tears and running noses, as well as respiratory problems.
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“Smog poses a long-term threat to people’s health. We are worried about the children who may suffer from other conditions that are even worse. Also, the polluted air brings with it the risk of cancer,” she said.
According to the Thai Public Health Ministry, more than 2.6 million people were affected by haze pollution in the past three years. Chiang Mai recorded the highest number at nearly 650,000, followed by Chiang Rai at about 467,000.
Air pollution has also affected tourism amid health concerns, Nion said.
“The northern region, which is popular among tourists for its natural scenery, saw a sharp decline early this year when the PM2.5 reading soared to 400 and higher,” Nion said.
A year ago, a program on air pollution education named “Blue School” was introduced to children from Banpafae-nongor-sansaimoon School.
The project, sponsored by Thai and international organizations, was launched in 2021. It aimed at educating primary school students on how to fight air pollution at school.
The program trained teachers through various workshops, and the teachers passed on the knowledge to their students.
“Eventually, we aim to make students become ‘active citizens’ so they can protect themselves and pass on knowledge to their family members with immediate beneficial health impacts,” said Nion, who is in charge of the program.
Under the program, students learn about particulate matter, how it threatens human health, and effective ways to deal with it.
“Seldom did students wear masks on polluted days before. But now, many have begun to wear masks on smoggy days, and they have even asked their family members to do the same,” said Tongsuk, the grade-six teacher.
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So far, more than 200 schools in Thailand have been involved in the program. Another 400 schools, including in Bangkok, will be joining it by the end of the year, according to Nion.
“Children are among the most vulnerable groups. We taught them to mark PM detector readings with five colors, namely blue, green, yellow, orange, and red. If the real-time monitoring index has a high reading, teachers will readjust school activities and the curriculum,” she said, noting that physical education classes can be held in a closed hall.
In Banpafae-nongor-sansaimoon School, Nion demonstrated a notebook-sized box — the air quality monitor. “It’s made in Thailand but the chip inside is from China,” she added.
Last August, a group of Chinese scientists visited northern Thailand to assist with the haze problem, thanks to Sittikorn Chantadansuwan, minister-counselor at the Thai embassy in Beijing.
They came with high-tech purifiers designed by the Shanghai Institute of Ceramics, under the Chinese Academy of Sciences. About the size of a small refrigerator, it can be operated both indoors and outdoors, with each one capable of treating 3,000 to 10,000 cubic meters of polluted air per hour.
“The purifier uses an electrostatic precipitator, or ESP, without a filter, which saves costs,” said Sun Jing, a researcher from the Shanghai Institute of Ceramics. ESP is a device that uses an electrical charge to remove impurities from the air.
Compared with the traditional purifiers, Sun said this one has an efficiency of 90 percent. “For (particulate) matter with a diameter of 5 micrometers or lesser, the purifying efficiency can be even higher, up to 99 percent,” Sun added.
She said the team has designed larger purifiers using the same principle, and they have proved to be effective in China.
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The largest, as tall as 16 meters, can purify 50,000 to 130,000 cubic meters of air per hour, providing solutions in large indoor and semi-open spaces.
Last year, Sun’s team donated four small-sized purifiers to Thailand with one kept in the Banpafae-nongor-sansaimoon School’s library.
After five months, a thick layer of dust was observed on the ESP modules. The record shows the PM2.5 levels in the library could be kept lower than 50 on average, while outside it was often above 200.
“We are glad to receive support from Chinese scientists. China has gained great success in combating haze in big cities and their experiences are meaningful to us,” said Chaiyon Srisamoot, the mayor of Mae Sai.
“We’ve seen emissions from diesel fuel and smog from agricultural burning since childhood but haven’t been aware of the problem and its long-term threats to health until the use of air quality indicators about five or six years ago when the haze became too severe, and resulted in allergies,” he added.
Chaiyon expressed his hope of having larger purifiers in Thailand to combat severe threats from haze pollution.
He said China’s innovative purifiers play an important role in protecting people, especially children and the elderly, from health threats.
“Still, public education and joint efforts from all sides to control pollution sources and promote health protection are crucial. This is the ultimate solution for a long-term benefit and it needs support not only from Thailand but also neighboring countries,” he said.