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High PM 2.5 levels this cool season could place you at risk of coronary artery disease


  • Cool season is a time of high air pressure, meaning that the air often remains calm and various types of pollution are unable to disperse properly from certain areas. This places those areas at risk of air pollution levels exceeding what would be considered safe.
  • Since 2013, the World Health Organization (WHO) has classified PM2.5 as a group 1 carcinogen. Moreover, PM2.5 is one of the eight leading causes of early death worldwide.
  • For every 10mg/m3 increase of PM2.5 in the bloodstream, there is a 5.9% increase in carotid intima-medial thickness. This can increase a person’s risk of brain and heart disease by up to 1.24 times, while also increasing their risk of an early death resulting from heart disease by 1.76 times.


High PM 2.5 levels this cool season could place you at risk of coronary artery disease

As we enter the cool season, many experts are beginning to warn people about high PM2.5 levels which are making a return to the Greater Bangkok Metropolitan area, and many people are once again wearing protective masks. The cool season brings with it high air pressure. The result of this seasonal change is calm weather systems that inhibit the dispersal of air pollution, which can cause pollution to exceed safe levels.

Components of PM2.5

Before they mix with steam, dust and smoke, the constituent components of PM2.5 are toxic gases including nitrogen oxide (NOx) and sulphur dioxide (SO2), as well as heavy metals, such as mercury (Hg), cadmium (Cd), arsenic and lead (As). Moreover, there is a high likelihood that PM2.5 will also contain polycyclic aromatic hydrocarbons (PAHs), all of which are harmful to the human body. PAHs are a direct result of numerous human activities, including: the burning of crops and fields undertaken within the agricultural industry such as in the North of the country, which causes a toxic smog that spreads beyond borders; transport and vehicle use resulting in exhaust fumes created by the burning of diesel and gasohol fuels; industrial production of volatile organic compounds from chemicals and industrial sources; and electricity production which, despite producing less PM2.5 than burning vast swathes of crops and the transport industry, still plays a significant role in the release of sulphur dioxide (SO2) and nitrogen oxide (NOx) into the atmosphere.

Beginning in 2013, the presence of these toxic substances has led the World Health Organization (WHO) to classify PM2.5 as a group 1 carcinogen. Moreover, PM2.5 is one of the eight leading causes of early death worldwide. The fact that PM2.5 particles are so miniscule means that the nose cannot filter the substances effectively and the particulate matter finds its way into the respiratory and circulatory systems, where it negatively impacts various organs. PM2.5 can lead to a deterioration of lung function, while also increasing the risk of emphysema, respiratory inflammation resulting from allergy symptoms, and cardiovascular disease, especially coronary artery disease and myocardial infarctions.

Research has found that for every 10mg/m3 increase of PM2.5 in the bloodstream, there is a 5.9% increase in carotid intima-medial thickness. This increases the likelihood of narrowing or clogging of the heart’s arteries, thereby increasing a person’s risk of heart disease by up to 1.24 times and heightening their chance of suffering an early death due to heart disease by 1.76 times.

Coronary heart disease and the resulting increase in annual fatalities

We are currently experiencing a shocking rise in the number of coronary heart disease cases. The causes of this can be put down to modern-day lifestyles that are unrecognizable to those of the past, particularly with regard to city dwellers who are so focused on their careers that they often neglect to exercise and end up obese or overweight. These groups are also more likely to smoke and to suffer from congenital health disorders (diabetes, high blood pressure and high cholesterol). There are also a number of unavoidable factors at play (age, gender and ethnicity), combined with constantly evolving pollution issues such as the presence of PM2.5 in the air.

Coronary artery disease is incurable so patients must therefore take medication for the remainder of their lives. Moreover, where symptoms deteriorate to the extent that the sufferer experiences chest pain, they may be required to have a balloon stent fitted to improve arterial blood flow. Some cases may be so serious as to warrant a heart bypass operation. For these reasons, protecting yourself from this disease is a matter of huge importance.

There are 2 main forms of coronary artery disease: acute coronary syndrome and chronic coronary syndrome.

  • The acute form of this condition can result in fatality should the patient not receive urgent medical attention. Sufferers of this condition may get tired easily and feel pain in the center of their chest that increases in frequency and severity despite not exerting any energy. They may also experience palpitations, profuse sweating and difficulty breathing. Acute coronary syndrome can lead to death or permanent disability, depending on the severity and length of time that the heart is starved of blood supply. Therefore, it is essential that patients receive medical attention as soon as possible. Should doctors confirm the occurrence of acute coronary syndrome, they will attempt to improve blood flow by using anticoagulant drugs and inserting a balloon stent into the affected artery.
  • Chronic coronary syndrome includes symptoms which come and go, and may involve a periodic tightness around the center of the chest. Patients may also experience a shooting pain that spreads to the left shoulder and jaw. These symptoms are usually associated with exertion, such as brisk walking, exercise or ascending stairs, all of which may lead to a tightness in the chest area that goes away once the sufferer sits down to rest. Should these symptoms persist, patients should seek urgent medical attention. Treatment generally comes in the form of making lifestyle adjustments and taking medication, although such medication must be taken for the duration of that patient’s life in order to prevent further arterial blockages. Healthy dietary choices and regular exercise are also required for the same reason. In extreme cases and/or where there is severely obstructed circulation meaning the heart cannot contract at normal rates, patients will be required to be fitted with a balloon stent. Patients suffering from multiple blockages or obstructions are usually advised to undergo a heart bypass operation that involves surgeons transplanting an artery sourced from the left arm or a vein sourced from the leg – taken anywhere from the inner ankle up to the groin – to bypass the obstructed arteries and allow for increased blood flow to the heart.

Protecting yourself against PM2.5

  • Wear an N95 approved safety mask which is made from high resolution fibers capable of filtering particulate matter 2.5. In addition to protecting against smog, these masks can help us to reduce our risk of heart disease.
  • Reduce the use of personal vehicles, especially bicycles and motorcycles, and instead opt to use public transportation.
  • Exercise only in low dust areas that are far from roads. You may want to exercise indoors or at a fitness studio instead of at public parks during this time.
  • Increase your consumption of fruits and vegetables or take supplements that contain vitamins and antioxidants, as these will help your body fight off the effects of particulate matter that enters your system.
  • Protect yourself more generally. Manage your weight by getting regular exercise, eat a healthier diet by replacing fats from meat with those found in grains and nuts and reducing salt intake, and quit smoking.

You can follow the air quality index in real-time at This is a website that provides air quality information for the Greater Bangkok Metropolitan region sourced from The World Air Quality Index, a non-profit organization created to increase awareness of air pollution around the world.

For those of you worried about the risk of developing coronary artery disease due to frequent exposure in areas containing unsafe levels of PM2.5, doctors recommend a calcium CT score assessment. This is a highly accurate screening technique that offers analysis for the amount of calcium plaque buildup in arteries, which medical staff can use to assist in prescribing appropriate treatment. Such a course of action can ensure initial steps are taken before serious symptoms are allowed to present themselves, thereby reducing a patient’s risk of suffering an acute coronary syndrome event.

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