Why is Bangkok’s air quality so bad?
When you wake up early in Bangkok you can see all the beautiful morning fog from your balcony, As you sip your coffee you realise it’s just Bangkok’s air pollution that’s making the sun rise aesthetic. Ranked the 36th most air-polluted country in the world, Thailand has been facing challenges when it comes to increasing its air quality.
Many factors translate to this mass pollution including internal & external contributions, lowering the quality of air. This article will go through the types of pollution affecting Bangkok and the reasons why Bangkok’s air quality is so bad.
Internal factors
As the city develops, the increase in machinery and industry causes bad air quality in the city. Vehicles, machines & factories commonly release toxic emissions that mainly contribute to Bangkok’s air pollution. With mega skyscrapers covering the natural airflow in urban areas and congested traffic releasing toxic gases, the city centre has become a breeding ground.
Vehicular emissions
Air pollution in Bangkok, with vehicular emissions emerging as the primary culprit, generates approximately 60% of the city’s PM2.5 emissions. Additionally, due to the high concentration of diesel vehicles, which make up a quarter of Bangkok’s registered vehicles, the situation is worsening.
These diesel-powered vehicles, many of which are ageing and fail to meet current emission standards, contribute disproportionately to the city’s air quality issues. Recent efforts by the Bangkok Metropolitan Administration (BMA) to address this problem have revealed that out of 135,000 vehicles inspected for emissions, only 2,141 failed to meet standards, with trucks accounting for 529 of these failures, proving the urgent need to address the ageing vehicle fleet on Bangkok’s streets.
High population density
Bangkok is the number most populated city in Thailand, it’s no surprise the city’s rapid urbanization has led to more pollution, with residential and commercial areas expanding into previously green spaces. This development often lacks proper public transport options, forcing residents to rely heavily on personal vehicles. Or most public transport are not pollution friendly at all.
External factors
Bangkok’s air quality problems extend beyond its city boundaries, with external factors amplifying the city’s pollution levels. Traditional practices across Thailand and neighbouring Southeast Asian countries, such as crop burning, contribute additional pollutants to the city’s already burdened atmosphere.
The city’s weather patterns compound these issues, as Bangkok’s geographical location and climate can trap pollutants, creating stagnant air conditions that allow contaminants to linger and accumulate over the metropolitan area.
Agricultural burning
Every year during Thailand’s dry season (November to April), the nation’s agricultural practices majorly impact air quality through a traditional farming method known as slash and burn, which dates back over 10,000 years. This technique, mostly done in northern Thailand, involves farmers burning crop residues like rice straw to fertilize their fields for the next planting season, however only contributing to roughly 18% of the country’s emissions.
The resulting smoke creates a thick smog that blankets northern cities like Chiang Mai, with the most severe period typically occurring between mid-January and mid-April. During this burning season, the landscape transforms dramatically – rice fields turn to dry earth, leaves fall, and the air quality deteriorates significantly, affecting not only local regions like Bangkok but also spreading to neighbouring countries like Myanmar and Laos.
Industrial Emissions
Factories-centric cities like Rayong or Samut Prakan are seeing an increase in factories that contribute to pollution. In these regions, you can see the expanding petrochemical sector, whose facilities release a steady stream of volatile organic compounds (VOCs) into the surrounding air.
These industrial emissions have cast an increasing side effect on the local environment, transforming what was once a coastal area into one of Thailand’s most pollution-challenged industrial hubs. The concentration of these manufacturing facilities within these cities’ industrial zones has created a compound effect, where multiple sources of pollutants merge to create a threat to air quality.
Meteorological Conditions
Bangkok’s air pollution gets worse during the dry season when the weather traps dirty air close to the ground, like a lid on a pot. When there’s little wind and high humidity, the polluted air just sits there instead of being blown away. This creates a blanket of pollution that hovers over the city, making the air quality particularly bad for residents. Especially, in urban areas where skyscrapers and huge buildings get in the way of the wind.
Different types of pollutants
Air pollution consists of two distinct categories of harmful particles: primary pollutants, which are released directly into the atmosphere from their sources, and secondary pollutants, which form when different airborne substances react with each other in the environment. These two classifications help scientists and policymakers better understand and address the complex nature of air contamination.
Particulate Matter (PM), with PM2.5 being particularly dangerous due to its ability to penetrate deep into the lungs. Other significant primary pollutants include Carbon Monoxide (CO) from incomplete fossil fuel combustion, Sulfur Dioxide (SOâ‚‚) from power plants, Nitrogen Dioxide (NOâ‚‚) from vehicle emissions, and Volatile Organic Compounds (VOCs) from everyday products like paints and solvents.
Secondary pollutants, on the other hand, form through chemical reactions in the atmosphere the ground-level ozone, which develops when VOCs react with NOâ‚‚ in sunlight, contributing to smog formation. Another crucial secondary pollutant is acid rain, which occurs when sulfur dioxide and nitrogen oxides interact with atmospheric water vapour, leading to environmental damage.
Primary pollutants | Secondary pollutants |
| Particulate Matter (PM) | Ground-Level Ozone (O₃) |
| Carbon Monoxide (CO) | Smog |
| Nitrogen Dioxide (NOâ‚‚) | Acid Rain |
| Sulfur Dioxide (SOâ‚‚): | Peroxyacetyl Nitrate (PAN) |
Bangkok’s bad air quality crisis stands out as a huge challenge shaped by both internal and external factors. Within the city, vehicular emissions stand as the primary contributor. This issue is worsened by an ageing fleet of diesel vehicles and the city’s dense urban development. The city’s geographical location and meteorological conditions, unfortunately, work against its favour. Bangkok’s climate tends to trap these various pollutants close to the ground. This creates a persistent blanket of contaminated air.
Being mindful of our environmental impact, even through small individual actions, can collectively contribute to meaningful change in the fight against pollution. While one person alone cannot solve the global pollution crisis, taking consistent steps to reduce our environmental footprint can create ripple effects. These ripple effects lead to better outcomes for our shared environment.
FAQs about why Bangkok’s air quality is so bad
What are the primary sources of air pollution in Bangkok?
The main sources of air pollution in Bangkok are vehicular emissions, industrial activities, and agricultural burning. An ageing fleet of diesel vehicles and factories in industrial zones contribute significantly to harmful pollutants in the air.
How do vehicular emissions affect Bangkok's air quality?
Vehicular emissions account for about 60% of Bangkok's PM2.5 pollution. Older diesel vehicles emit high levels of nitrogen oxides and particulate matter, worsening the city's air quality.
What impact does agricultural burning have on Bangkok's air pollution?
Agricultural burning, especially during the dry season, contributes around 18% of Thailand's emissions. This practice releases smoke and particulate matter that deteriorate air quality in Bangkok and surrounding areas.
How does Bangkok's high population density influence its air pollution?
High population density leads to more vehicles on the road and increased industrial activity, both of which raise pollution levels. Dense urban development also traps pollutants, preventing their dispersion and worsening air quality.
What actions are being taken to reduce air pollution in Bangkok?
Bangkok is implementing vehicle inspections to enforce emission standards and promoting cleaner fuels. Efforts also include improving public transportation, reducing industrial emissions, and collaborating regionally to minimize agricultural burning.
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