How to protect yourself from PM 2.5 in Bangkok!

by Karl von Luckwald / June 5, 2023

PM 2.5 in Bangkok is a severe problem. Especially during the winter season (November – March) Thailand’s capital is choked by smog. This article elaborates on PM 2.5 in Bangkok and its causes. It will explain what PM 2.5 exactly is and maps out how to protect yourself from it.

What is PM 2.5?

PM 2.5 (abbreviation for Particulate Matter) are particles that are smaller than 2.5 micrometers (µm).

To visualize how small this is, just pull out a hair and hold it between your thumb and index finger. That hair you’re staring at is most likely between 50 to 70 micrometers (or 0.05 to 0.07 millimeters in diameter.)

the size of a human hair

Human hair measures between 50 to 70 micrometers (µm).

PM 2.5 particles have a maximum size of 2.5 micrometers. That’s at least 25 times smaller than that hair that you’ve just pulled out. PM 2.5 is invisible to the naked eye, thus dangerous and easy to underestimate.

What is the difference between PM 2.5 and PM 10?

If you’ve heard of PM 2.5 you may be also aware of PM 10. The difference is size. PM 2.5 refers to particles below 2.5 micrometers. PM 10 refers to particles below 10 micrometers. Thus PM 2.5 is part of PM 10.

PM10 particles are larger than PM2.5 and are less likely to be inhaled deep into the lungs. However, they can still have negative impacts on health, particularly for individuals who are more vulnerable such as children, the elderly, and those with preexisting respiratory or cardiovascular conditions.

PM 2.5 in Bangkok
Viruses such as the Coronavirus can be 25 times smaller than PM 2.5

How dangerous is PM 2.5 in Bangkok?

PM 2.5 in Bangkok is a severe issue. Especially during the cold season between November and March air pollution hits extremely unhealthy levels. January and February are usually the worst months with PM 2.5 concentrations above 100 micrograms per cubic meter (ug/m3) on many days. This exceeds the WHO safe threshold by almost 10 times.

You may be surprised though that PM2.5 in Bangkok is a seasonal phenomenon. During the hot and rainy season (April – October) air quality can be great and even better than in some cities in Europe.

PM 2.5 in Bangkok
While air pollution worsens between November and March, air quality between July and September remains relatively good

Despite seasonality and relatively good air between July and September, Bangkok is a city with a severe PM2.5 problem. According to the UN, the annual average PM2.5 exposure exceeds the WHO safe levels by 4.6 times. The UN estimates furthermore, that roughly 60,000 people die each year in Thailand from the long-term effects of air pollution.

What causes PM2.5?

PM2.5 can include organic matter (dander and spores), and inorganic matter like dust from several sources. Motor vehicles, power plants, road construction sites, stoves, and heating systems, as well as metal and steel production, cause microscopic dust particles that infiltrate invisibly into the air. PM2.5 can remain in the atmosphere for days or even weeks, and even travel large distances, paying no mind to international borders or geographical boundaries.

In Bangkok, for instance, road traffic is considered the dominant source of PM2.5. Inefficient combustion of diesel and petrol vehicles and daily traffic jams pollute the air enormously. Especially during the cold season when there is no rain and only very little wind, PM2.5 accumulates in the air and causes toxic haze.

PM2.5 in Bangkok is caused by traffic jam
Bangkok’s daily traffic jams cause dangerous PM 2.5

How is PM 2.5 harming our health?

The effects of PM2.5 on human health are devastating. Since PM 2.5 particles are so tiny they may easily enter our respiratory system, bloodstream, and brains.

Possible consequences are manifold and range from respiratory inflammation and thrombosis to lung cancer and heart attacks. Scientists also found numerous indicators pointing to an increased risk of neurological diseases such as dementia, Alzheimer and Parkinson’s, all stemming from heightened PM2.5 exposure. 

PM 2.5 once in the bloodstream may clog veins and arteries
Once PM 2.5 is in the bloodstream it may clog veins and arteries

Who is particularly vulnerable to PM 2.5?

Some population groups are particularly vulnerable. Older people with weak cardiovascular systems share similar risk levels with pregnant women since air pollution has been linked to low birth weight, miscarriages, and birth defects. 

Children comprise the third major risk group. Children are usually very active and inhale more air per unit of body weight than adults. Thus, they run the risk of inhaling particularly large amounts of polluted air. Because children’s brains are still developing, PM2.5 – once it enters their bloodstream – damages brain cells and affects cognitive development.

In addition to harming the brain, children’s exposure to air pollution increases their risk of other diseases later in life. Lung cancer, Pneumonia, and Ischemic heart disease are often caused and made worse by air pollution, and are more likely to occur with prolonged exposure to unhealthy amounts of PM2.5. That’s why children, in particular, need protection from air pollution.    

children run
Children run risk of inhaling particularly large amounts of polluted air

How to protect yourself from PM 2.5 in Bangkok

As soon as PM 2.5 in Bangkok is high do the following:

  • Close all windows and doors in your home, office, or school
  • Install air purifiers and external air quality monitors to clean and monitor the air. Air purifiers keep your indoor air clean
  • Wear facemasks when outside. But be careful: not every mask keeps you safe from PM 2.5. We recommend using N95 masks
  • Restrict outdoor activities. Skip the outdoor workout and make sure that the air in your gym is clean – talk to the gym manager if it’s not! 
  • Don’t smoke indoors or near children. 
air purifiers protect your from pm 2.5 in bangkok

Air purifiers like the Sqair keep filter PM 2.5 and help to breathe safely at home

What we can do to reduce PM 2.5 in Bangkok

PM 2.5 is mainly caused by humans. Whenever we drive a car, travel by plane, or use electricity, it will lead to air pollution. We can help reduce PM 2.5 in Bangkok by being aware of our habits:

  • Let’s use BTS and MRT trains more frequently.
  • Let’s less idle our cars when stuck in traffic.
  • Let’s switch to EVs
  • Let’s only use electricity when necessary
  • Let’s not burn any trash, waste or plants.  


Karl von Luckwald

Karl von Luckwald

Since moving to Thailand in 2019, Karl noticed the lack of scientific integrity in air purifier and water filter reviews. In response, he founded WE DO AIR to champion unbiased, science-based evaluations and empower consumers to make better-informed decisions.

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