For several months, PM2.5 dust has exceeded 50 microgrammes per cubic metre (µg/m³) in many provinces in Thailand, which is considered unsafe. In some areas, such as Chiang Mai, Chiang Rai and Mae Hong Son, PM2.5 levels have reached over 500µg/m³. While some people are aware of the dangers of PM2.5 pollution, others do not take it seriously.
At the online forum, "PM2.5 Hazard Dust Crisis", recently organised by Chiang Mai University (CMU), Assoc Prof Dr Chalerm Liwsrisakun, head of the Department of the Faculty of Medicine at CMU, expressed surprise at seeing people without masks outdoors despite the negative health effects of PM2.5 being over 200-300µg/m³. Assoc Prof Dr Chalerm also presented a photo of a runner who suddenly collapsed after participating in a competition held on a day with high levels of PM2.5 pollution. He pointed out that PM2.5 pollution can affect the cardiovascular system.
"This kind of situation happens at running competitions almost every year, but the events are still held. The case of a runner who experienced sudden cardiac arrest can happen after a few hours of running," Dr Chalerm said.
Another speaker at the forum, Asst Prof Wan Wiriya, lecturer at the Department of Chemistry of the Faculty of Science at CMU, explained that PM2.5, or particulate matter 2.5, refers to tiny particles in the air that have a diameter of less than or equal to 2.5 microns (µm).
Asst Prof Wan studied and compared PM2.5 dust in Chiang Mai and Bangkok and discovered that on smoky days, nano dust in Chiang Mai was smaller than 0.1µm and smaller than dust in Bangkok. A study of PM2.5 dust on filter paper revealed that most dust particles in Chiang Mai were between the sizes 0.65-2.1µm. This means the dust in Chiang Mai can easily be absorbed into the respiratory system.
"Small particles have higher carcinogenic substances than large particles. Dust particles in Bangkok are bigger than in Chiang Mai because most of the dust in the capital comes from traffic and construction while dust in Chiang Mai is from crop burning," said Asst Prof Wan.
Assoc Prof Dr Chalerm further explained that particles smaller than 2.5µm can penetrate the lung while PM0.1 can enter the bloodstream. Smaller particles are more dangerous because they can go through any part of the body.
According to Assoc Prof Dr Chalerm, air pollution can cause acute and chronic health effects. Acute conditions can be divided into severe and less severe. Less severe acute conditions include nosebleeds and conjunctivitis, and severe acute conditions involve issues with the respiratory system, vascular disease and infection. Meanwhile, chronic conditions include decreased lung function, emphysema, chronic kidney disease, and lung cancer and other malignancies.
Assoc Prof Dr Chalerm mentioned a 2021 report from the World Health Organization which stated that 2.2 million people die prematurely every year from air pollution both indoors and outdoors. Among these deaths, 29% are from ischemic heart disease, 27% from stroke, 22% from chronic obstructive pulmonary disease, 14% from lung cancer and 8% from pneumonia.
Air pollution not only affects adults but also unborn babies. A study indicated that PM2.5 particles could be found inside the placenta as tiny particles can enter a mother's bloodstream. The WHO reported that air pollution impacts children's health including premature birth, low birth weight, neurodevelopment issues, cognitive ability, childhood cancer and death.
The 2021 study conducted by the Ministry of Public Health on the lung cancer mortality rate in relation to smoking prevalence in Thailand proved that PM2.5 pollution has a severe impact on health. The study reported that the three provinces with the highest smoking rates were in the South -- Krabi, Satun and Nakhon Si Thammarat. However, provinces in the North, Lampang, Lamphun and Phayao, which had lower smoking rates, had the highest rate of lung cancer deaths.
Dr Rungsrit Kanjanavanit, cardiologist and the director of CMEx Lifelong Learning Center, Center for Medical Excellence at Chiang Mai University, presented a graph showing the triggers of myocardial infarction. The graph indicated that 10µg/m3 of air pollution increases the risk of myocardial infarction by a factor of 1.03 while the use of cocaine increases the risk by a factor of 25.1.
"Based on the graph, the effects of PM2.5 pollution may not seem as scary as cocaine use at the individual level. However, air pollution is a factor that affects the entire population because everyone must breathe. When multiplied by the population, the impact becomes significant on a population level," said Dr Rungsrit.
Although many studies indicate the major source of PM2.5 pollution in the North is from crop burning, Dr Rungsrit said that people should not point fingers at farmers since everyone plays a part in air pollution.
"Due to our demand for meat, the animal feed industry must grow more crops for livestock. In order to keep their investment as low as possible, farmers often choose to use the slash-and-burn method. If we want to implement appropriate crop production processes, the investment cost will be higher. We have to discuss who will pay the higher cost. Will consumers shoulder the cost and buy meat at higher prices or should manufacturers be responsible for this cost?" the cardiologist said.
Since the Clean Air Act has not been approved, people have to protect themselves. Asst Prof Wan, lecturer at the Department of Chemistry of the Faculty of Science, advises that N95 and nano masks are effective in protecting people from PM2.5.
"I tested nano masks in Bangkok and Chiang Mai and found they can filter tiny particles as small as 0.075µm. Since the smallest particles found in Thailand are sized 0.1µm, nano masks can protect people. Many people asked me about TF98 and JN95 masks. These are just brand names; the symbols TF98 and JN95 do not indicate any standard of filtration efficiency."
As for KN95 masks from China and KF94 from South Korea, they are 70% to 80% effective in protecting against PM2.5. However, there are many fake KN95 and KF94 masks which may contain metal. If masks have a strong smell, be aware of them.
Asst Prof Wan also suggested drivers do not need to install air purifiers because there is a built-in air purifier in all cars.
On April 10, about 1,700 people in Chiang Mai signed a petition to sue Prime Minister Gen Prayut Chan-o-cha, the National Environmental Board and the Securities and Exchange Commission for failing to use their legal authority to address the PM2.5 pollution crisis in the northern region.
Dr Rungsrit, who was one of the plaintiffs, said people should not have to purchase clean air. The government should provide clean air for everyone. The cardiologist decided to file a class action lawsuit because the government did not fulfil its duties. He also said a proper political agenda can make changes and save millions of lives.
At the end of the forum, Asst Prof Wan and the audience suggested a practical action to solve crop burning.
"Let them burn. There are laws to regulate crop burning, but they cannot be enforced. We have been living in an area where PM2.5 pollution has exceeded safe standards for three months, but the authorities have done nothing. Thus, let them burn, but make the burning period short and during this time, there should be holidays."
