Breathing the Invisible Threat: PM2.5 Pollution in Bangladesh

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Breathing the Invisible Threat: PM2.5 Pollution in Bangladesh

Written by- Abdullah Al Masum

Edited by- Syeda Fatima Sultana

Take a deep breath. Does it feel clean? For millions of people in Bangladesh, especially in cities like Dhaka, every breath carries an invisible enemy—PM2.5, the fine particulate matter that contributes to some of the worst air pollution on the planet. You can’t see it, smell it, or touch it, but it’s silently killing people and suffocating the environment. PM2.5 has transformed the air we rely on for life into a carrier of disease, disability, and death. Bangladesh now ranks among the most polluted countries in the world, with Dhaka often sitting at the top of the World’s Most Polluted Cities Index. This silent killer is a pressing public health crisis.

(Source: The Business Standard)

PM2.5 Explained: A Deadly Intruder

Particulate Matter (PM) refers to a mixture of solid and liquid particles suspended in the air. While some particles, like dust, dirt, or smoke, are large enough to be visible to the naked eye, others are microscopic and can only be detected with an electron microscope. Among the various sizes of particulate matter, PM2.5 is particularly dangerous. This term refers to particles that are 2.5 micrometers or smaller in diameter—more than 100 times thinner than a human hair.

How small is 2.5 micrometers? Think about a single hair from your head. The average human hair is about 70 micrometers in diameter – making it 30 times larger than the largest fine particle.

(Source: EPA).

These particles remain suspended in the air for long periods, making them hard to avoid. The primary danger of PM2.5 is that, due to their small size, they can travel deep into the lungs, enter the bloodstream, and wreak havoc on the body. This particulate pollution is not just an environmental nuisance—it’s a silent assailant that directly affects human health.

The Dangerous Reality of PM2.5 Exposure

Exposure to PM2.5 is measured both indoors and outdoors, with the World Health Organization (WHO) recommending that the PM2.5 level should not exceed 12 μg/m³ over a 24-hour period. Unfortunately, in Bangladesh, especially in Dhaka, these levels are often surpassed. Studies suggest that when PM2.5 levels exceed 35 μg/m³, the air becomes unhealthy, leading to serious health problems, particularly for individuals with pre-existing conditions like asthma. Prolonged exposure to levels above 50 μg/m³ can result in severe health complications and premature death.

The risk is not limited to short-term health problems. Long-term exposure to PM2.5 has been linked to increased rates of chronic bronchitis, reduced lung function, and a higher risk of developing heart disease and lung cancer. Vulnerable populations—such as children, the elderly, and those with heart or lung issues—are at an even greater risk. As the Indoor Air Hygiene Institute recommends, maintaining a PM2.5 level of 12 μg/m³ or lower is essential to prevent long-term damage, with no frequent spikes above 35 μg/m³.

The Alarming Air Quality Levels in Bangladesh

Air quality in Bangladesh, particularly in urban areas, has become a significant health concern. According to the Ministry of Environment and Forests, Government of Bangladesh, Dhaka has the highest levels of air pollution, with PM2.5 concentrations reaching 150% above the World Health Organization (WHO) guidelines. This is equivalent to smoking 1.7 cigarettes per day. In contrast, Sylhet, the cleanest city in the country, still exceeds the WHO limit by 80%, equating to smoking 1.2 cigarettes daily.

A report detailing the Estimated Population-Weighted Annual PM2.5 Levels (2019–2021) further emphasizes the stark differences in air quality across Bangladesh. Urban areas consistently experience higher levels of PM2.5, attributed to traffic, industrial emissions, and construction activities. In Mymensingh, the highest average PM2.5 concentration was 103 µg/m³, while Sylhet recorded the lowest at 55 µg/m³. The data clearly shows that all divisions in Bangladesh exceed WHO’s safe PM2.5 limit, underscoring the urgent need for measures to improve air quality nationwide.

These elevated pollution levels pose serious health risks, with long-term exposure linked to respiratory diseases, heart conditions, and even premature death. Immediate action is required to reduce emissions and mitigate the harmful effects of air pollution for the health of the population.

(Source: Ministry of Environment and Forests, Government of Bangladesh. National Air Quality Management Plan (NAQMP) 2024–2030, MOEF Portal.)

Dhaka: A City Suffocating in Its Own Air

The situation in Dhaka is nothing short of alarming. According to the World Air Quality Report of 2023, the city’s PM2.5 levels were over 16 times the WHO’s annual safety limit. In fact, PM2.5 concentrations in Dhaka rose by more than 20% in 2023 compared to 2022. There were months when the levels exceeded 100 μg/m³, with some instances even breaching 150 μg/m³. These levels are far beyond what the WHO considers safe, putting the health and well-being of the entire population at grave risk.

The Devastating Death Toll

This air pollution crisis isn’t just an inconvenience—it’s a devastating public health catastrophe. In 2021, at least 236,000 lives were lost in Bangladesh due to air pollution. That’s 236,000 mothers, fathers, children, and loved ones who died prematurely because of the deadly air they were forced to breathe. The toll is horrifying, showing just how much PM2.5 is taking a life-threatening toll on people in the country. The air we breathe has become more than just a resource—it’s a silent killer, slowly and silently claiming lives.

Sources of PM2.5 Pollution in Bangladesh:

In Bangladesh, PM2.5 comes from a variety of sources, including brick kilns, vehicular emissions, construction dust, and the burning of biomass for cooking. A study by the Centre for Atmospheric Pollution Study (CAPS) found that 30% of the air pollution is caused by unplanned and uncontrolled road digging and construction work in Dhaka .

Other sources of air pollution include:

Brick kilns and factories:29% of air pollution
Vehicle exhaust fumes:15%
Transboundary air pollution:10%
Household and cooking stoves:9%
Waste incineration:7%

Major Sources of Pollution:

The key contributors to PM2.5 pollution in Bangladesh include construction sites and traffic congestion, particularly in Dhaka.

Systemic Problems: Local and Global Pollution

Nearly 1,600 kilns in the Dhaka Division contribute about 10% of the airborne particulate matter (PM) pollution in Dhaka’s airshed. Average seasonal particulate concentration varies from 25 to 100 µg/m³ due to brick kiln emissions, but clusters of kilns can cause pollution hotspots with levels as high as 200 µg/m³. Dhaka’s overall PM10 pollution is about 200 µg/m³, and PM2.5 levels reach around 100 µg/m³ (2007), much higher than the WHO standards of 20 µg/m³ and 10 µg/m³, respectively. The density of PM10 worsens during the dry season (December-March), reaching over 450 µg/m³, one of the highest levels in the world. This contributes to pulmonary, respiratory, and neurological illnesses, causing an estimated 5,000 premature deaths

Vehicle Pollution: A Growing Concern

The roads of Dhaka also contribute significantly to pollution. According to the Bangladesh Road Transport Authority, as of January 2022, there were 5.08 lakh vehicles across the country without fitness certificates . Many of these vehicles are outdated and run on inefficient engines, exacerbating the city’s traffic gridlock and increasing particulate pollution. Additionally, open waste burning—common in both urban and rural areas—releases PM2.5 along with a range of other hazardous chemicals.

PM2.5 Sources and Seasonal Variations in Dhaka

A study on PM2.5 pollution in Dhaka, Bangladesh, highlights two primary sources of pollution: biomass burning and fossil fuel combustion. Biomass burning, which includes the open burning of agricultural waste, and fossil fuel combustion, such as vehicle emissions and industrial processes, contribute significantly to the city’s air pollution.

The study also reveals distinct seasonal variations in PM2.5 levels. During the winter season, PM2.5 levels are much higher, with an average of 178.1 µg/m³, compared to 30.2 µg/m³ in the monsoon season. The increase in winter pollution is mainly attributed to large-scale agricultural burning that occurs in the Indo-Gangetic Plain.

To track these sources, the study employed specific markers. Potassium (K) was used to identify PM2.5 from biomass burning, while Sulfur (S) was used to mark pollution from fossil fuel combustion. Through regression analysis, researchers were able to separate the contributions of these two sources by analyzing daily PM2.5 data and adjusting for potassium and sulfur levels. This approach provides valuable insights into the major sources of pollution in Dhaka and helps in developing targeted strategies to control it.

Black Carbon’s Contribution to Glacial Melting

Black carbon, a key component of PM2.5, absorbs sunlight and heats the atmosphere. This contributes to the melting of glaciers in the Himalayas, which in turn increases the risk of floods in Bangladesh, a country already highly vulnerable to climate-related disasters.

Air Pollution and Climate Change

Air pollution and climate change are closely interlinked, and both are expected to worsen with increasing urbanization and shifts in climate patterns. The report highlights the urgent need for proactive measures in the health sector to effectively address these interrelated crises. It emphasizes the critical importance of immediate intervention to reduce air pollution to ensure sustainable development and foster green growth (Source: BDnews24).

The Environmental Toll of PM2.5 Pollution

PM2.5 pollution doesn’t only harm human health; it also takes a significant toll on the environment. The hazy skies over Dhaka and other major cities serve as a visible reminder of the invisible particles clogging the air. This smog reduces visibility, disrupts transportation, and damages the tourism industry.

Numerous scientific studies have shown that particulate matter, especially PM2.5, not only affects visibility but also disrupts the climate, ecosystems, and materials. PM2.5 impacts visibility by altering how light is absorbed and scattered in the atmosphere. Some components of PM2.5, such as black carbon, contribute to climate warming, while others like nitrate and sulfate have a cooling effect. As a result, ambient particulate matter (PM) has both warming and cooling properties on the climate.

PM2.5 can also adversely affect ecosystems, including plants, soil, and water. When deposited on surfaces, it can impact plant growth, water quality, and clarity. The metal and organic compounds in PM have the potential to alter plant growth and yield. PM deposition on materials leads to soiling, which damages various structures.

Is Particulate Matter a Problem Indoors?

Part of the particulate matter found indoors originates from the outdoors, particularly PM2.5. These particles enter indoor spaces through doors, windows, and leaks in building structures. In addition, indoor sources of particulate matter include biological components, such as pollen, mold spores, dust mites, and cockroaches, many of which are allergens. Other indoor activities, like smoking tobacco, cooking, burning wood, candles, or incense, also generate particles. Furthermore, indoor pollution can result from chemical reactions of gaseous pollutants emitted by household products like cleaning agents and air fresheners .

For a country like Bangladesh, where agriculture forms the backbone of the economy, this issue is particularly concerning. PM2.5 also accelerates climate change. Many air pollutants, including greenhouse gases, come from the same sources, such as coal-fired power plants and diesel-fueled vehicles. Some of these pollutants, such as black carbon (a component of fine particulate matter), have short lifespans but contribute significantly to climate warming. Other short-lived climate pollutants (SLCPs), including methane, hydrofluorocarbons, and ground-level ozone, are much more potent than carbon dioxide in warming the planet. For instance, methane contributes to ground-level ozone, which, according to the Climate and Clean Air Coalition and the Stockholm Environment Institute, causes about a million deaths annually and is 80 times more potent than carbon dioxide in warming the atmosphere over a 20-year period. Addressing SLCP emissions can deliver immediate benefits for both air quality and health, as well as mitigate climate change .

Bangladesh’s Battle Against PM2.5 Pollution: A Path Forward

The PM2.5 Crisis and Its Consequences

Bangladesh faces a severe air pollution crisis, with particulate matter (PM2.5) being one of the leading environmental health threats. PM2.5, which includes fine particles smaller than 2.5 micrometers, is linked to respiratory and cardiovascular diseases, leading to premature deaths. These tiny particles not only harm human health but also have a broader environmental impact, including reduced visibility, climate alteration, and ecosystem degradation. Particularly in urban areas like Dhaka, air pollution levels frequently surpass safe limits, contributing to smog, disrupted transportation, and the deterioration of materials and infrastructure.

Health Risks of PM2.5 Exposure in Bangladesh

Exposure to PM2.5 above WHO guidelines significantly increases the risk of various health issues. A 1% increase in exposure leads to:

8% higher probability of breathing difficulties.
5% higher probability of wet coughs.
1% higher risk of lower respiratory tract infections.
20% higher probability of depression in high-pollution areas.

Vulnerable Groups Affected by PM2.5 Pollution

PM2.5 pollution affects everyone, but certain groups are more vulnerable to its harmful effects, including children, pregnant women, the elderly, and low-income communities.

Children: In Dhaka, 40% of school-going children suffer from respiratory diseases linked to air pollution. Exposure to PM2.5 can stunt lung growth, impair cognitive development, and increase the likelihood of chronic conditions like asthma. Moreover, Bangladesh ranked fifth globally for deaths among children under the age of five due to air pollution. The long-term impact can affect children throughout their development, from pregnancy through early childhood.

Pregnant Women: Exposure to high levels of PM2.5 increases the risk of premature births and babies with low birth weight, contributing to adverse health outcomes for both mothers and infants.

The Elderly: Older adults are particularly susceptible to the effects of air pollution, which exacerbates cardiovascular and respiratory conditions, increasing the risk of strokes, heart attacks, and premature death. A study by the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b) found that air pollution contributes to 13% of all deaths among people over 65 years old in Dhaka.

Low-Income Communities: Vulnerable populations in low-income communities are at a heightened risk of suffering from the detrimental health effects of air pollution, with limited access to healthcare and preventative measures.

Impact on the General Population: Even healthy adults are not immune to the consequences of long-term exposure to PM2.5. Chronic obstructive pulmonary disease (COPD), lung cancer, and cardiovascular diseases are all linked to prolonged exposure to PM2.5. In fact, Bangladesh ranks second globally for air pollution-related deaths per capita, trailing only Nepal . This highlights the urgent need to address air pollution in Bangladesh to protect public health and reduce the overwhelming burden it places on vulnerable populations.

Solutions and Steps Towards Cleaner Air

Regulating Brick Kilns Brick kilns in Bangladesh are a major source of PM2.5 emissions. Despite some progress, such as the introduction of zigzag kilns, stricter regulations are necessary. The government should push for the transition to cleaner technologies, such as vertical shaft kilns or compressed block production, to minimize emissions significantly.

Cleaning Up Traffic Traffic is another primary contributor to air pollution in Dhaka. Measures such as phasing out old, inefficient vehicles, encouraging the use of electric and hybrid vehicles, and expanding public transportation systems (e.g., metro rail) will be key. Introducing congestion pricing during peak hours can help reduce traffic congestion and emissions.

Dust Control in Construction Construction activities in Dhaka often contribute to dust pollution, which exacerbates air quality issues. Implementing dust control measures like covering materials, using water sprays, and erecting green barriers around construction sites will help minimize these effects. Strict enforcement of regulations is essential to ensure compliance.

Promoting Green Energy Rural areas in Bangladesh still rely heavily on biomass fuels like wood and cow dung for cooking, contributing to indoor and outdoor air pollution. Transitioning to cleaner energy alternatives like LPG and biogas can greatly reduce emissions. Government subsidies and awareness campaigns can play a vital role in making these technologies accessible to rural households.

Greening Urban Spaces Planting trees and creating green spaces in urban areas can help absorb pollutants, especially PM2.5. Trees such as neem, banyan, and bamboo are effective in filtering particulate matter. Greening initiatives should be encouraged to improve air quality and enhance the livability of urban spaces.

Public Awareness and Education Many people in Bangladesh are unaware of the risks associated with PM2.5 exposure. Public education campaigns can raise awareness about the health dangers of air pollution and encourage citizens to take protective measures like wearing N95 masks and monitoring air quality through apps like AirVisual.

Signs of Hope: Global and Local Success Stories

There are positive examples both locally and globally. Bangladesh’s efforts to reduce emissions from brick kilns through the adoption of zigzag kilns have led to a 40% reduction in emissions. Furthermore, the expansion of Dhaka’s metro rail network is expected to reduce vehicle emissions significantly over time.

Globally, cities like Beijing and Delhi have shown that aggressive policies can reverse air pollution trends. For instance, Beijing managed to reduce PM2.5 levels by 35% within five years through policies such as coal bans and vehicle restrictions. Bangladesh can take inspiration from these success stories to tackle its own air quality crisis.

Every Breath Counts: A Call to Action

Bangladesh is at a critical juncture. The toxic air we breathe threatens our health and well-being, but it is not too late to make a change. Through stronger regulations, investment in cleaner technologies, and widespread public education, Bangladesh can protect its citizens and the environment from the devastating effects of PM2.5 pollution.

The goal is clear: a future where children can play outside without the fear of respiratory diseases, where the skies are no longer covered in smog, and where every breath we take is a step toward a healthier, more sustainable Bangladesh. But achieving this future requires action—now.

Sources:

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