Bangkok's air pollution in data - Not as bad as it seems

[TPDH]

The general sentiment on this forum seems to be that Bangkok has some of the worst air pollution in the world and that living here long-term will lead to severe health implications and a drastically reduced lifespan. However, this perception is far from accurate and greatly exaggerated.

 

Bangkok’s air quality is undoubtedly a concern, and it is not good. However, the purpose of this post is to answer two key questions: “How bad is it?” and “What does it mean for my health?”

 

How Bad Is Bangkok’s Air Pollution from a Global Perspective?

According to IQAir, which ranks cities worldwide based on air pollution, Bangkok was ranked 1,052nd globally in 2023, with an average PM2.5 level of 21.7.

Source: https://www.iqair.com/th-en/world-most-polluted-cities?continent=&country=&state=&sort=-rank&page=1&perPage=50&cities=WJv6Pqdvj8ph9xkuZ,

 

Similarly, the AQI (Air Quality Index) ranks Bangkok 813th globally in 2024, with an average AQI of 76.

Source: https://www.aqi.in/world-most-polluted-cities

 

From my observation, the majority of people on this forum likely believe Bangkok is among the top 30 most polluted cities in the world. This is simply not true. Even if you filter for cities with populations of 500,000 or more, Bangkok does not make it into the top 50.

 

While rankings provide context, what truly matters is the actual pollution level and its impact on health.

 

How Bad Are Bangkok’s Pollution Levels?

Bangkok’s average PM2.5 level of 21.7 and AQI of 76 are categorized as “Moderate” according to the Air Quality Index developed by the U.S. Environmental Protection Agency (EPA). The EPA defines “Moderate” air quality as: “Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution.”

Source: https://www.airnow.gov/aqi/aqi-basics/

 

Therefore, Bangkok’s air quality is scientifically classified as “Acceptable” by the most widely used indices for measuring air pollution. Yet, discussions on this forum often portray it as “Very Unhealthy” or “Hazardous,” which is inaccurate for the vast majority of days throughout the year and based on 24/7 measurements from hundreds of independent sensors across the city.

Although air pollution spikes during January-April, it only reaches unhealthy levels on a small minority of days throughout the year. The annual average remains consistent with the figures provided earlier.

 

For those of us wanting to live in large cities, many alternatives also come with some level of air pollution. For example, Singapore has an average yearly AQI of 47 compared to Bangkok’s 76. No air pollution is usually not an option for big cities.

 

Bangkok Life Expectancy

The life expectancy of Bangkok residents is 79 years, which is comparable to developed countries. This is despite Thailand having poorer healthcare and higher risks of work- and traffic-related deaths.

 

If Bangkok residents experienced a significantly reduced lifespan due to air pollution, how could they still live, on average, to 79 years old? Bangkok's air has been polluted since before the 90s . The answer is that air pollution in Bangkok does not significantly reduce lifespan, as explained next.

 

Source: https://data.who.int/countries/764

Source: https://globaldatalab.org/shdi/table/lifexp/

 

Reduced Life Expectancy Due To Air Pollution

The Air Quality Life Index (AQLI), developed by researchers at the University of Chicago, shows how air pollution reduces life expectancy. The AQLI index is used by governments, the World Bank, World Health Organisation and many others.

 

"According to the AQLI, Bangkok’s average PM2.5 concentration of 21 µg/m³ exceeds the World Health Organization (WHO) guideline of 5 µg/m³. This elevated pollution level reduces the average life expectancy of Bangkok residents by approximately 1.5 years."

Source: https://aqli.epic.uchicago.edu/the-index/

 

To a large extent we can validate this conclusion further by knowing that the average life expectancy in Bangkok is 79. If you asked people on this forum, many would likely believe that living in Bangkok for decades would likely reduce your lifespan by up to 10 years. This is an extreme misconception and far from the truth.

 

Health Implications

Three of the most common diseases caused by air pollution are asthma, lung cancer, and chronic obstructive pulmonary disease (COPD). However, Thailand does not rank among the top 30 countries for any of these diseases in either total cases per year or cases per capita, according to organizations like the WHO and the World Cancer Research Fund.

 

As an example to provide context: Sweden, which has negligible air pollution and only 5.4% of its population smoking, has 40 cases of lung cancer per 100,000 people, compared to Thailand’s 20.6 (men) and 9.3 (women) per 100,000. Similar trends are found across other developed countries with low air pollution and low smoking rates.

Source: Thailand Cancer Data

 

The global prevalence of COPD is 13.1%, but in Thailand it's only 5.6%.

Sources: ERS Journal

Source: https://www.researchgate.net/publication/263376205_COPD_prevalence_in_12_Asia-Pacific_countries_and_regions_Projections_based_on_the_COPD_prevalence_estimation_model

 

 

Asthma follows a similar pattern. In Thailand the prevalence rate of Asthma is only 3.1%. Well below most modern first-world countries.

Source: Our World in Data

 

This does not mean these conditions are nonexistent in Thailand, but they are not as widespread as many believe. In fact, over a dozen first-world countries with low air pollution face larger problems with these diseases.

 

For less severe conditions like runny nose, cough, or itchy skin, the EPA states that only people who are "unusually sensitive" to “Moderate” air pollution may experience these symptoms. For these individuals, it may be wise to move to a place with little to no air pollution. But these people are a minority.

 

Mitigation Strategies

For most office workers, exposure to moderate air pollution can be limited to 2–3 hours daily or less. I'd imagine that most office workers in large cities don’t spend more than this amount of time outdoors anyway, even if there had been no air pollution, so their freedom or quality of life is not significantly impacted.

 

Additional mitigation strategies includes: Using air purifiers at home and work so that during the vast majority of the day you're breathing in close to perfect air, Wearing PM2.5 masks when riding motorbikes or in heavy traffic, Maintaining good overall health to reduce vulnerability to air pollution and limiting outdoor activity during days with 150+ AQI.

 

With these precautions, office workers can likely reduce the impact of air pollution on life expectancy to well below one year. While there is no exact data on this, if the average life expectancy reduction in Bangkok is 1.5 years due to air pollution, it seems reasonable to assume that limited exposure and mitigation strategies could reduce this impact by at least 30%.

 

Conclusions

1. Bangkok’s air quality on a yearly basis is classified as “Moderate” and “Acceptable” by leading measures like the Air Quality Index. It is not classified as “Unhealthy.”. Nor is it classified as "Good".

2. The reduced life expectancy due to air pollution for Bangkok residents is approximately 1.5 years, consistent with their high average life expectancy of 79 years.

3. Office workers implementing basic mitigation strategies can likely reduce the potential life expectancy impact to below one year.

4. Serious diseases caused by air pollution are not strongly prevalent in Thailand, further supporting these conclusions. As for experiencing milder symptoms, according to the WHO and the AQI index "moderate" air pollution mostly affects sensitive groups of people.

 

Final Words

I have no agenda here and I am not interested in picking sides. My only goal is to understand how bad Bangkok's air pollution is and what it means for my health. Yes, Bangkok politicians should prioritize reducing air pollution in Bangkok to below WHO's guideline of 5 µg/m³. Yes, some people are more exposed or sensitive to air pollution than others, and children are indeed at higher risk.

 

Ultimately, while Bangkok’s air quality is not good and especially not during this period, it is not as detrimental as many believe. By understanding the data and taking simple precautions, it is entirely possible to live a very healthy life here as many of us have done for many years.

[Gottfrid]

It´s bad

[CygnusX1]

Excellent article. On days when I can’t even see the nearby island of Koh Larn from Jomtien, I know instinctively that breathing in that air must be very bad for my health, but in science, data is always king, no matter how obvious or logical your theory. The problem is that it’s so hard to reliably compare the health of people living in places with  high air pollution with others in areas with clean air, due to so many confounding variables.

[Lorry]

OP is full of fallacies, factual, logical and statistical.

Just 2 of them,  at the beginning:

 

Bangkok has a very distinct smog season,  which is now.

Air quality in September is not bad.

It doesn't make sense to average Bangkok air quality over the whole year. 

 

"Life expectancy of Bangkok residents": Bangkok is not a city of Bangkokians, born there,  living there, and dying there after 79 years.  It's a city of migrants,  the vast majority of residents weren't born here  (especially if you define Bangkok as the area inside there city limits), didn't even grow up here. 

The concept of "life expectancy of Bangkok residents" is nonsensical. 

 

Later on, he excuses PM 2.5 with the fact that Westerners used to smoke...for heavens sake!

 

Who paid for this apologetic nonsense?