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OCF Conversation #02: Air Pollution: A Brewing Public Health Emergency in Bangladesh with Dr. Abdus Salam


Our Common Future (OCF) is a podcast that seeks to dive critically into the issues of our contemporary world in hopes to use the nuanced understanding to reimagine the future of the people, planet, and prosperity.

Every week, Shamir Shehab sits down with thinkers, makers, and leaders from across disciplines to have a multidisciplinary understanding of our world today. In this episode of the podcast, he sits down with Dr. Abdus Salam to explore the complex and terrifying world of air pollution, discuss the many forms and hazards of air pollution, its many shapes and nature, causes and consequences of air pollution, the state of air pollution in Bangladesh, and how we can combat the growing problem of air pollution in Bangladesh, and much more. This is an absolutely fascinating and poignant listen and read in its entirety. 

Dr. Abdus Salam is a Professor at the Chemistry Department of Dhaka University and a prolific researcher who has been working with different aspects of air pollution for the last twenty years. A leading expert in the field, Dr. Salam has been involved in a diverse range of national and international research teams on the subject, having worked with a wide array of themes, research techniques, and methodology.

Show Notes:

[00:03:58] Prof. Dr. Abdus Salam introduces himself and shares his air pollution work. 

[00:04:40] Prof. Dr. Abdus Salam explains air pollution and how it works. 

[00:09:00] Prof. Dr. Abdus Salam explains how different particles can cause harm to the human body. 

[00:11:35] Discussion regarding air pollution in major cities of the world and Dhaka. 

[00:15:58] Reasons for air pollution in Dhaka during winter and transboundary air pollution. 

[00:19:05] Trends of air pollution over the years in Bangladesh. 

[00:29:56] Seasonal air pollution in Bangladesh. 

[00:37:10] Sources of air pollution in Bangladesh. 

[00:44:48] Current state of air pollution in Dhaka.

[00:49:30] Impacts of air pollution on human health, climate and economy. 

[01:01:12] How air pollution affects mental health. 

[01:04:25] The way forward 

[01:16:56] THE CLEAN AIR ACT OF 2019. 

“Our Common Future Conversation” is hosted by Shamir Shehab, produced by Shamir Shehab and Ruhul Kader; the audio is edited and mixed by Tawhidul Islam Rafi; transcription by Ayushi Khan and transcription review by Saleh Md. Sadi and  Maliha Mahjabeen. Special thanks to Bohubrihi from Shikho for technical support. OCF Conversation is a joint initiative of Future Startup and BYEI. You can listen to our whole conversation by following “Our Common Future Conversation” on Apple, Spotify, Google, or wherever you get your podcasts and Future Startup website. 


(Note: The conversation was recorded in Bangla, this is a rough translation in English. It is not fully edited for grammatical accuracy and may contain spelling errors.) 

Shamir Shehab: Dear audience, I welcome you all to another new episode. Today's episode is about air pollution, which is a very important concern for Bangladesh's public health. To speak about this topic, we have a special guest with us today who is an esteemed researcher on air pollution in Bangladesh and has been researching this for over a decade. We will get to learn about our guest and his research, and also about the general state of air pollution in Bangladesh. So, Professor Salam, welcome to Our Common Future podcast!

Professor Abdus Salam: Thank you for your warm welcome. I am Abdus Salam, a Professor at the Chemistry Department of Dhaka University. My research and studies, be it in the university or abroad, is all related to air pollution. For the last 20 years since the year 2000, I have been working on different aspects of air pollution, and for the last 10 years, I focused on air pollution in Bangladesh and am still researching this topic. 

Firstly, since you want to know about air pollution, let me start by saying exactly what it is. For our daily livelihood, all of us need some kind of food. In every second, in every moment, we need air, and this air must be clean. In this year, 90% of all city dwellers don't get clean air; this air is contaminated. Why is this air getting contaminated? It is because if we go back 200 years to the industrial time when the world was not developed, the air was at a certain level. 

Today in our contemporary world, for our daily activities, everyone is very modern and mechanical; we are constantly using some sort of device, like computers or mobiles, or riding cars and planes, all of which is in some way using energy. To attain this energy, we are using something as well, through which many chemical matters are entering the atmosphere and polluting it. These chemical matters are of two types: the ones that are in the gaseous state, and those that are in a solid-state. 

The sources of the gaseous matter include the fuel we use, the smoke that comes from burning wood, when diesel, octane, petrol, kerosene, or coal is burned, and so on. Other than that, the different construction activities we do, or when we dig the road or make buildings, culverts, poles, and bridges, through all of these activities some sort of matter always enters the air and pollutes it. These gaseous matters are commonly sulfur dioxide, nitric oxide, ozone, CFC, different volatile organic carbon. 

Another thing is the solid matter. They're solids, but they're extremely tiny. Examples of these include PM2.5 and PM1; PM2.5 refers to particles smaller than 2.5 micrometers that are suspended in the air. PM1 refers to the matter suspended in the air which is smaller than 1 micrometer. What is within these matters PM1 and PM2.5 then? Within them are different chemical substances such as black carbon, ash, organic carbon, also different types of sulfates, nitrates, and phosphates. There may even be metals: arsenic, lead, cadmium, mercury attached to some dust and moisture. So overall, the air contains two main matters which are solids and gasses which come into the air due to our daily activities, and the reason these are contaminants is that they already exist in the air at a natural level, but we are newly introducing them into the air. By doing this, when we cross the natural level of these preexisting matters, this is called pollution. If these contaminants exist above that certain level, then it harms us. 

To summarize what I want to say, there are two types of matters which are gas and solids, and the sources are all from our daily activities, and the levels are much higher than the standard level at which these should be present at the point it starts hurting people. This is the overall air pollution.

Shamir: You spoke about two types of particles: PM2.5 and PM10. Out of these two, which is more harmful?

Salam: I was actually talking about PM1. PM10 is another common contaminant; this refers to the different sizes of suspended particles in the air. PM10 is bigger than PM2.5, and in turn, PM2.5 is bigger than PM1. 

The smaller the particles, the higher their ability to harm, because the smaller particles can easily enter the human system through the nose. The bigger particles are unable to make it through. The smaller the particles, the more they can harm people, which is why PM2.5 is much more dangerous than PM10, and PM1 is more dangerous than PM2.5. There are even smaller particles which are called "ultrafine particles" and are smaller than 100 nanometers, or smaller than PM1. 

There are tons, no, trillions of particles suspended in the air which are in the 3-100 nanometer size range, but we don't have too many studies about these in our country, there are a lot in other countries. But they are very small particles and hence very dangerous because they can stay suspended in the air for a long time, have different chemical interactions, and also enter the human body very easily to interact with the chemicals inside it or in the environment. As a result, the smaller the particles, the higher the chance it has to harm. PM10 is less harmful than PM2.5 and PM2.5 is less harmful than PM1. 

Shamir: Okay, thank you. We would like to know the state of PM2.5 in Dhaka, but before that, I want to go back to something you mentioned earlier. 90% of the people who live in the city are subject to polluted air. So, air pollution was a very global phenomenon; in the 70s and 80s, we noticed that air pollution has been a massive problem in San Francisco, USA, and London. 

We have recently noticed that the countries that are economically progressing very fast, such as China and India, face huge issues with air pollution; to such an extent that even schools had to close in some cases. 

So in Bangladesh, we have noticed newspaper headlines that stated that Dhaka is one of the top cities in terms of worst air quality for the last few years. So is air pollution a very recent phenomenon for Bangladesh, or did we not have proper data or information back then to be amply aware of? What is your opinion on this matter?

Salam: Thank you. Firstly, you mentioned the developed countries, especially the example of the USA, London, and Japan. If you look into these, there is an event called "London Smog" which happened around the year 1954 that people bring up whenever there is a matter of pollution or the environment. If you also think about the examples of California and Japan, around 70-80 years ago, these countries were heavily polluted. Why were they polluted? People initially didn't care too much about air pollution. Industries would work using coal engines, which are not in use anymore. What I was saying is when these countries began developing industrially, then their pollution episode started, and then they realized that industrial activities must be controlled so that they cannot pollute very heavily. These countries began trying to solve these and they did end up solving them. In Japan, you will notice there is no pollution, especially air pollution. The amount of PM2.5 they have is 7-8 microgram per meter cube, which if you compare with Dhaka, on average during winter the amount is 300-500µg/m^3 and in the rainy days of June-August, it stays within 15-20. There is no comparison between these numbers, especially 7 and 500 or 15-20. This means the range for Bangladesh starts from twice the amount to 50 times the amount of Japan. They solved their problems, but we were not yet able to solve ours. So these countries are now developed, but when they were first starting developing industrially, they faced a lot of these air problem issues, which they addressed and currently don't face to that extent anymore in America, England, and Japan. However, they have other problems; America now has natural forest fires, England has dust events from Spain or other areas, natural forest fires also happen in Australia. These countries now face problems different from industrial or vehicular pollution, which are very controlled. To go to your point that in global comparison, the pollution levels in Bangladesh are truly very high. Among these initial few countries for the last three years 2018, 2019, and 2020, Bangladesh ranked first in terms of PM2.5 pollution. The annual average was 90-100 µg/m^3. So you can imagine just how mismanaged we are, and how many types of pollution we are subject to. Along with us, India and China are facing these problems as well. Every year at the end of October there are certain events in India due to which a lot of biomass and waste is burned in locations such as Haryana and Punjab. The impacts are largely faced by Delhi as well as the PM2.5 amounts range from 700-1000µg/m^3 and schools are obligated to close down. This even happened in Beijing a few years ago, where an event caused the PM2.5 levels to go up to 1100µg/m^3. Maybe we didn't get such a huge amount in Bangladesh yet, but as we reach 300 or 500 µg/m^3 we are gradually on that path. 300µg/m^3 means it is 12 times the amount of the WHO recommended value for PM2.5 of 25µg/m^3. So, simply ponder what state we are in. Another point you mentioned was whether this was Dhaka-centric or for the country; air pollution is a global problem. If you produce a pollutant in Dhaka, it won't just stay there, it will spread to its neighboring countries, with huge dependence on meteorology like the wind direction, moisture content, sunlight, and so on. Normally in winter, all the brickfields are operated, which is a cause for the pollution that is faced in Dhaka at that time. Rice parboiling factories too, these only operate in winter. Furthermore, the wind comes from the Northside, and in that direction, we have two giant countries that are currently very famous worldwide for pollution namely China and India. So, a proportion of the pollution formed in those two countries is carried over to Bangladesh by the north winds. Hence in winter our own personal pollution greatly increases from brickfields and rice parboiling industries, and on top of that pollution arrives at our country from abroad. In those three to four winter months from November to February, we don't get any rain either, so the air pollution state of Bangladesh during winter gets truly awful. This event is slowly increasing by the day as well. 

This pollution event is not necessarily new or old. When we consider the age of Bangladesh starting from the war of Independence, out of the 50 years we've had so far this has been the state for about 20 years now. At one time if you entered Dhaka through the airport, the air would be visibly black with a huge amount of black carbon in it. At that time the black carbon was measured at almost 40µg/m^3 which has reduced down to around 7-8µg/m^3 now. 

In 1996-1997, many newspapers would often write about how the air in Dhaka is full of lead. The lead comes from gasoline, and in 1997 leaded gasoline was banned in Bangladesh which brought down the amount of lead. Back then, the lead was at 460ng/m^3 which was the second-highest behind Mexico. This has now come down significantly, but in the last few years this is slowly increasing again because of increased use of battery-powered machines, and these batteries are reportedly melted in industries in Jatrabari and Syedabad at night to regenerate and reuse them. Furthermore, electronic waste has also greatly increased now. People did not use too many phones, televisions, or ovens a while ago compared to now, which means we have a lot of e-waste now. A portion of this is also burned in our country which also emits lead causing its amounts to begin increasing once again. 

Overall, the situation in Bangladesh is not exactly new; I would say at least 30 years of events have happened so far here and the air pollution is gradually increasing by the day. Just two months ago we published a paper where we tried to show the air pollution trend of the last 17 years using both satellite and surface data. We have no indication of it decreasing, it is actually gradually increasing because industrialization and our lifestyle are changing. 

Bangladesh used to be primarily an agriculture-centric country, but now garments and other industries occupy the number one spot. We are shifting to industry from agriculture as it is generating a lot of revenue, so with more investments into industries their number is increasing as well which goes hand in hand with burning fossil fuels. These burned fuels are releasing pollution which causes the air pollution to drastically rise. If you simply think about the population, we have a significantly higher number of people now compared to 30 years ago, especially in Dhaka, where almost 2 crore people are residing. With this increased amount of people there will be increased activities, and again, increased pollution. 

This is the reason why the story of our pollution isn't completely new, I would say air pollution has been with us for the last 30 years or so. People would focus more on water pollution in the past but today our bad state of the air has given Bangladesh a negative branding.

Shamir: You mentioned a lot of interesting points! The fact that you saw in the data from the last 17 years that air pollution is indeed common and has increased by the day, is not a very recent story. So for the last 10-15 years, our population has been exposed to very high levels of air pollution. So we will come to the health implications of these later, but for now, I want to highlight two interesting points you brought up; firstly you spoke about transboundary pollution, and secondly about how if we create pollution in or around Dhaka then it won't only stay in Dhaka but will spread to different districts depending on some factors. So when I was living in Beijing and South Korea for a while, I personally experienced something; there is a huge desert in Mongolia which is hundreds of miles away from Beijing but if there is a storm created in that desert for any reason, its impacts would befall on Beijing along with many other places as well since the air would take away the pollution to other places. Similarly, when I spoke to my colleagues and friends in Seoul and asked what the cause of air pollution in Seoul was, they blamed China and said the pollution mainly came from there. Upon further research, I found that there actually was some validity to this argument, as the wind and other factors would cause air pollution to get carried away to a different country. So for Bangladesh, is there any sort of study or personal observation which quantifies the amount of air pollution coming in from neighboring countries? Also, I know Dhaka has a lot of air monitoring stations but is air quality being properly monitored in other places outside of Dhaka? 

Salam: Thank you, you started off with a very interesting topic. We always say, "it is easy to blame others." We are reluctant to talk about our own faults and are quick to blame others. So the Chinese say pollution came from Japan, but Japan says it came from China, and the Koreans say something similar too. This isn't completely baseless though, there is definitely some logic behind it as in certain times of the year pollution moves from one place to another. Dust in Africa can even go and hit America. Singapore is close to us and they are a small country with little to no pollution, but they face haze events too from peat coal burning in Indonesia. The pollution that comes into Bangladesh is known as the IGP, the Indo-Gangetic Plain. 

If you look at the satellite photos of wintertime, I could show them to you if you wish, you will notice there is a haze always present throughout Pakistan, the Himalayas, Nepal, Bangladesh, and ending at the Bay of Bengal. This whole area always has a haze above it. This haze is a combination of our own pollution and the pollution that we get from our neighboring countries which people now know as IGP Haze or Indo-Gangetic Plain Haze. It starts every year during winter around mid-November and starts slowly going away in February. Sometimes it persists for 3-4 days or even a week, and sometimes it stays for a day or two, but overall you will notice a haze above this area. Now how much of this haze is because of Bangladesh and how much because of neighboring countries? 

We released another paper in collaboration with two American universities: the University of Wisconsin-Madison and the University of Saint Louis, in which we used data from a monitoring station near the American Embassy and Mirpur to form a model called a GAM model. Using that model, we calculated how much comes from where and found out that up to 40% of pollution is transboundary in wintertime and comes from the outside. So to clearly answer your question, if there are 100 micrograms of pollution in Dhaka, 40 micrograms will be from abroad while 60 micrograms are our own pollution, which is a lot too. The WHO annual value is 10 microgram which means it's 6 times the recommended value. And on top of that, we are getting 40 micrograms more from abroad. So we do have a quantitative measure now; of course, this is a recent technology that was not as prevalent before but we can see that 40% of pollution comes from abroad. 

Secondly, the point here is that since the monitoring stations are mainly in Dhaka then how are other areas being monitored?. So there are mainly two types of data being used: one is ground-based data, and the other is satellite-based data. Satellite-based data cover more or less the entire country, or even the whole world depending on the different satellites. The validity of this data is contested though, so this data is validated by cross-checking with the surface level data. In another recent paper we published in an Elsevier journal called Atmospheric research, we showed how in Bangladesh half of the west, south, and north is highly polluted during many times of the year but the east is usually less polluted since the haze that comes from abroad comes from the north and west after which it travels towards the Bay of Bengal but is not able to cover the entire country. Hence the big cities such as Rajshahi, Barisal, Dhaka, Chittagong, Khulna, these cities are pretty polluted usually but Sylhet is relatively less polluted than these. The other cities are often facing air pollution and PM2.5 values are much higher than the WHO guideline, where it is usually 2-3 times the amount of the annual recommended average. Furthermore, it is not exactly true that data collection is Dhaka-centric as the Department of Environment has about 17 air monitoring stations, two of which are in Dhaka and the rest are scattered across the country. We ourselves have two monitoring stations, one in Dhaka and one near the Bay of Bengal in Bhola in which we have been measuring the Aerosol Optical Depth for the last 13 years. 

The Aerosol Optical Depth is the column depth from the earth's surface to the sun, and in order to measure the extent of pollution in this column, seven different wavelengths are measured across their own frequencies, and the significance of each wavelength is used to measure the signal that it can take. This is a project done by the joint collaboration of Dhaka University and NASA and the data is being continuously monitored. It's hard to believe, but in the winter months of February, the pollution around the Bay of Bengal is even worse than that of Dhaka. This is because the transboundary pollution and pollution produced in Dhaka slowly move towards the Bay. Around 20-25th February, the winds change direction, and hence the air that was over the Bay now returns to the land. So, the pollution from both the Bay of Bengal and Dhaka make the pollution levels higher than Dhaka at that particular time. The overall yearly pollution scenario is different, but for these months the Bay has much higher pollution than Dhaka.

Also as you mentioned the other villages other than Dhaka, the pollution in Bangladesh is highly seasonal. Let's talk about four main seasons: monsoon, winter, post-monsoon, and pre-monsoon. Now for two comparisons, starting with the monsoon. In the monsoon time of June, July, and August, there is a lot of rain during which the pollution levels in Bangladesh is much lower than that of winter. This year the levels were much lower than the WHO guidelines for a lot of days, which was an exception for this year because of the strong lockdown which halted a lot of activities that reduced pollution. Even normally, however, pollution is typically much lower during this rainy season than in the winter. In post-monsoon, it is lower than winter but slightly higher than monsoon. Hence June, July, and August has the lowest pollution in Bangladesh while December, January, and February is the time of the highest pollution events. 

Shamir: So the rain is playing a role in decreasing the pollution. Is this because during the rain, the suspended particles and pollutants fall to the ground? What exactly happens during the rain?

Salam: Yes. These do settle down even without rain, but when it rains a lot of the pollutants wash out and fall to the ground. This may be dust or different chemical components that are scavenged into the air. But even if it doesn't rain, there are generally two types of deposition: dry deposition and wet deposition. 

Dry deposition is when different particles go through different chemical and physical interactions to gradually increase in size. Once they reach a certain optimum size they can no longer float in the air and begin deposition. When these dry particles fall to the ground we call it dry deposition. 

Wet deposition is when pollutants are brought to the ground by rain or snow. Yes, pollutants do decrease a lot with rain. The water does the same thing as you normally would with cleaning or washing dirt off of clothes, by bringing the pollution to the ground. Hence, we see lower levels of pollution during the monsoon.

Shamir: That's interesting. From my observation from when I was in Beijing, we noticed that the air there was nicest after the rain, which would usually be polluted normally. However, back in 2019, I observed that the pollution levels didn't decrease significantly after rain in Dhaka. This is my very limited observation as maybe it takes longer for these pollutants to decrease, but I would like to hear your thoughts about it.

Salam: Yes, so a lot of the pollutants that were suspended in the air will decrease with rain. However, when the sun comes out after the rain it stops the pollutants that were on the earth's uncovered surface which we have a lot of that can re-enter the atmosphere as dust. 

You may have noticed how the sunlight causes a lot of dust to return to the air after the rain and brings the pollution levels back up, but normally the rain brings the pollution down. I am not sure what pollution data you are talking about from 2009 but I don't think we had very advanced or quality data and measuring techniques at the time.

Shamir: I'm talking about 2019 actually, where the AQI and the air quality were measured by the Dhaka US Embassy station.

Salam: The US Embassy station is okay, but the AQI machine you are talking about, I have one of those too in my office, they are not outdoor machines but for the indoors. The effect of the rain will not be reflected if you keep it at home or on the balcony, which is why perhaps you didn't notice it, and overall I do have thoughts about the AQI sensor, the general public are the people who often measure the AQI. Some may have kept it in front of their industry, some kept it in their office to see the pollution. But we do need some more studies to check whether the number it is giving is okay or not.

Shamir: That is a very important point. I too noticed that the variation was very significant when I was looking at different data sources so I was wondering what the reason may be. 

Another interesting point you mentioned is transboundary pollution. From a policy implication perspective, no matter how much we try, 40-50% of pollution may come from neighboring countries. So to take care of pollution issues, regional cooperation is necessary if we want to see proper results. We can discuss the policy implications later. 

To go back to the topic, in this case, what are the factors behind the significant air pollution in Bangladesh? We know industrialization is one, but other than that what are the sources? Is it from the transport sector, brick kilns? What are the sources of this air pollution according to your studies?

Salam: It is important that we do Source Apportionment Studies to determine the sources of air pollution. We do have a few of those, but not too many of these are solid or systematic studies. 

However, from the studies that we do have, the main sources of pollution are firstly traffic and cars. The vehicles that run on diesel, gas, and octane are not properly maintained which causes a huge amount of pollution to be released from these cars. The second worst source is industries, mainly brick kilns, even though brick kiln industries have declined lately and other industries have increased. The third biggest is the construction activities we have. We have a lot of ongoing mega projects, but even the regular ones like road fixes, housing construction, and high-rise building constructions are causing a lot of dust pollution. For fourth place: around 70% of the people in Bangladesh live in the villages and 80% of this population use traditional cooking stoves which depend on the burning of wood, hay, and leaves. These four are the main pollution sources. 

Other than that there are smaller sources; the generators that are turned on when we don't have electricity cause a lot of incomplete combustion, petrol pumps experience a lot of leaks, gas can leak out of cars parked in garages, steamers cause a lot of pollution and so on. These are the small events. 

So, the big events are the ones I mentioned: firstly traffic vehicles, secondly industry including brick kilns, thirdly construction activities and four is biomass burning. These are the major sources of air pollution in Bangladesh.

Shamir: The fourth source you mentioned is quite interesting, especially the wood used in cooking in the villages. 

Salam: I would like to add something here that we found in a study. These are source-based air pollution. 

Now if we think about energy-based air pollution; our energy sources are liquid fossil fuel, solid fossil fuels, and biomass. Liquid fuels are octane, diesel, petrol, and kerosene. Solid fuel is coal which is used in brick kilns and electricity generation. The third is biomass or wood, which is used in cooking, or the waste burning like leaves and paper. 

So among these three main sources, we tried to find how much pollution comes out of each in a study. We found up to 12-15% comes from coal. The rest almost equally come from fossil fuels and biomass burning. When we speak about Dhaka we can say not much biomass is burned here, but a lot of this happens in the villages and that influence does fall on Dhaka. So we were able to very accurately predict using this study that liquid fossil fuel and biomass almost equally contribute about 40% of the pollution while 10-12% comes from coal. This is the energy-based estimation for the air pollution contribution. 

Shamir: The 12% of the coal, is this 12% from the energy sector or from overall pollution?

Salam: It contributes to pollution, especially a substance called black carbon which is also responsible for global warming and bad human health. I just spoke of the pollution that comes from this black carbon, and how much of it is released from coal. This can be determined by looking at whether it's dead carbon or live carbon. Dead carbon comes from fossil fuels aged millions of years and freshly prepared coal comes from biomass if its age is a few days to a few months. So this study compared the contributions of these two carbons very clearly.

Shamir: Very very interesting. So for the sake of our audience's understanding, 12% of the coal-based pollution comes from carbon pollution.

Salam: Yes, not the total carbon though, but black carbon which is the black smoke you can see, up to 12% of this comes from coal.

Shamir: Okay, thank you. So now, I would like to ask about the overall situation of air pollution in Bangladesh to explain to someone who, let's say, does not have any idea what AQI means. Especially, what is the overall state throughout the last 4-5 years and how we place if you could frame these in a way so people who are not aware can understand. 

Salam: I can talk about Bangladesh's situation in two contexts — firstly a global context, and secondly how it does according to the national guidelines, namely WHO (World Health Organization) which is most important. 

So if I start from a global context; if you compare the state of Bangladesh with a European or Japanese city we will find that some pollutants are present up to 10 or 200 times more in comparison. Also in some studies, we found that the amount that should normally be present is only followed for about 5% of days every year. For the remaining 95% days, the amount is much higher than the WHO guidelines. 

Overall, our situation is pretty bad, especially during winter the pollution levels are much higher than both global and guideline levels, up to 10-12 times the value, whether you talk about the main 5 criteria pollutants or only PM2.5. Now that we are wearing masks for the COVID-19 pandemic, it is indirectly saving us from air pollution too. 

The practice of masks may have not been common before but now that it is more normal the health situation may improve. We noticed that over the last two years, mask sales increased a lot while inhaler sales saw a relative decline as asthma patients are safer due to mask use. Masks can filter out a lot of big particles and PM2.5, even if they cannot do so for a lot of ultrafine particles. Pollutants are typically about 10-12% higher in Dhaka. The villages might not be extremely bad, they typically have nicer air and better winds compared to Dhaka. 

Shamir: I think COVID-19 has been very devastating for the whole world and your life too I'm sure, but there has been a silver lining in Bangladesh and other places, which is people have gotten the chance to see some blue skies and clearer air. So this thing you mentioned, that pollutants can be 200 times higher, this is very alarming. So what are the implications of this? I was reading a headline yesterday, that if we can decrease air pollution then people's life spans can increase by 5%. So, besides the health implications it has since it causes respiratory diseases, can you explain some implications of air pollution in terms of other things like economic productivity, lifespan, economic loss, or even mental health of people?

Salam: That was a short question but the answer is very long. You hit three main points with the question: what is the impact of air pollution, how does it affects the economy, and how it affects lifespan. Let’s explore this one by one. Firstly, due to air pollution, three big things happen - first it affects human health, second, it affects climate and global warming, thirdly it affects the overall ecosystem. 

Firstly for health impact. The smaller the particle, the easier it can enter the human system. These particles start to close down alveoli, which are the tiny air sacs of the lungs. If this persists for a long time, then a disease called COPD can develop, which can also affect the heart and cause death. The metallic pollutants present in air pollution can affect the kidney. The ultrafine particles can enter through the nose and make certain brain cells inactive, and we never know which cell will be made inactive so we don't know what action can be hampered due to this. This cell damage in the brain can lead to certain parts of our body not working, especially on our cognitive ability. 

Next, we have tiny holes along our eyelids. Air pollution can clog these and cause issues. Recent studies have shown direct relationships between air pollution and diabetes and blood pressure. Overall, a lot of the major diseases are related to air pollution: heart attacks, brain strokes, pressure, diabetes, eye issues, and cancer. These huge issues are all aggravated thanks to air pollution.

Shamir: If I could ask you a supplementary question, are there any studies in Bangladesh that measure how air pollution levels have affected human health? For example, you mentioned that inhaler sale went down as the air was probably in a better state than before. So overall, what kinds of data and information are known to you about this?

Salam: Yes, even if it isn't a lot, there are a few published papers on the effect that befalls on children due to air pollution. There is a machine called a peak flow meter, it is a very simple study that measures your breaths to give a reading; a reading above 300-500 means your lungs are working fine. It turns out around 50-60% of children cannot breathe normally, and this is prevalent around the schools and areas that are especially polluted. 

Another global study that included Bangladesh proved that the overall lifespan of the population is decreasing due to air pollution. In another data you inquired about cancer, if you compile consecutive data throughout the last few years, you will notice that every year more and more patients are getting hospitalized due to cancer. If you notice during winters especially (except for this winter since the COVID pandemic changed the situation) the ICUs are often filled up with patients because of heart stroke. This is also related to air pollution since it is higher during the winters and comprises the respiratory system of people as they cannot breathe fresh air, which leads to heart attacks. 

These studies, data, and published research for air pollution and health implications are available for Bangladesh even if not to a great extent. As I mentioned, 50-60% of children in Bangladesh cannot breathe to the fullest extent, every year, many lakhs of cancer patients are admitted to the hospital, and the ICUs are always filled up during the winter months as they are attacked by the higher pollution. Diabetes is also a major disease in Bangladesh, many people have it but it has been on the rise recently and it is proven that air pollution has a role to play in these numbers. 

Now to come to the fact that people's lifespan has gone down. There have been two recent studies about this, one stating that globally the average lifespan goes down by 2-3 years due to air pollution, and for Bangladesh specifically, it is 5 years. Another 2019 study showed that globally there is a 5-year decrease, while people can lose up to 8 active years in the India and Bangladesh region due to air pollution. 

The next point was how this affects the economy. Recently we measured the cost borne due to the five main pollutants for the last 12 years. We found that around 2008-2009 when our GDP growth was relatively low the cost was around 2% of our GDP. In 2019 the cost on our economy due to air pollution was up to 5%. This is a huge direct cost that is going away from our GDP. 

Now for an indirect cost, when I worked with a lot of foreigners for projects they often stated how they would be very careful every time they came to Bangladesh for work and some would avoid visiting it entirely because they would practice caution once they saw the studies for the air quality data of Bangladesh and saw it was hazardous. So here this affects our investment since so many people are avoiding coming here and working with us. This is a real fact since I have personally spoken to a lot of these people who got posted here in Bangladesh but didn't come after seeing the air quality data. We are facing a financial loss in this aspect. The aforementioned hospital costs are also a burden on people, and the 8 active years of the lifespan that is being decreased could have been years that a person could have worked to provide for the country. 

Another direct effect can be on how all the launches and cars that operate during winters face compromised visibility due to the smog and hence there can be accidents or congestion. This is a financial loss as well. If we calculate all of these we can see the huge impact that comes to the economy due to air pollution. 

Shamir: Thank you very very much, especially that final point about our economic loss. If we do not truly quantify these, we cannot make a move for good policies. From the data and information that you mentioned, up to 5% of our GDP is lost, which is a huge amount of money and productivity. Hopefully, our policymakers can think a little deeply about this as this is not only a public health hazard but we are facing an economic issue because of this as well. If we can do things in a more balanced and sustainable way then we can see that a public health benefit can bring an economic benefit as well. In fact, I read a report by the Guardian last week which mentioned a study by the UK which said that improved air quality can positively benefit people's mental health as well. The methodology of the study showed that it was quite a rigorous study with huge sample size. Even though you may not be an expert in the mental health sector, I would like to hear your thoughts about this.

Salam: As I mentioned, the few ultrafine particles which are deposited on our brain, we don't know all the impacts that it causes as the brain is complex, and we can never know its true mechanism of working. 

Another factor is that people are now finding relationships between these ultrafine particles and the reason people lose their temper, become more irritated, and experience increased blood pressure. Big researchers who work with public health and global studies like in the UK and USA are now looking into this and have very solidly proven this relationship. 

The way we spontaneously laugh when we see each other or like to be joyful, if we see the air and weather are bad then it does not come to us naturally, which is a mental health matter. 

You have rightly brought up the relationship between air pollution and mental health and even behavioral changes, and there have also been previous studies investigating this. I forgot to mention earlier that air pollution causes a lot of harm to children. There is harm in unborn children even because the mother is inhaling this dirty air and the baby inside of her is harmed by having their cognitive ability reduced, defected organs, weight loss, and lots of disabled babies. Studies have proven that this is all due to air pollution, these babies aren't even born but air pollution affects them. 

Shamir: That was extremely insightful and also very alarming. Overall, what you meant to say is that COVID has affected us all, but air pollution can be classified as a pandemic in slow motion. We can't see this with our naked eye or there isn't any robust discussion about this, but its impact is no less than the pandemic itself. 

Salam: Yes, this is kind of an invisible killer.

Shamir: Exactly. So what is the hope for improvement from this dangerous scenario? What are the solution and ways forward? What is your thought on this?

Salam: Like you mentioned how you were in Korea, and then you also brought up London and California. They always lived in a polluted situation, but now they are very clean because they could control this pollution. We have to do the same. So we have SDGs, Sustainable Development Goals which Bangladesh has signed as well in which health and wellbeing is a point, climate change is a point, and air pollution is also a point in a small part. So to achieve the targets of these SDGs we have no choice but to reduce air pollution. To do this we first need to accurately quantify the causes, amounts, and overall scenario of air pollution and gain a solid understanding of it. 

Secondly, based on that, we must do source apportionment studies or emission inventory studies and then use its results to go into action. The action is regarding how we can control the specific sources so that we have less emission. Like how I mentioned earlier about using liquid fossil (octane, petrol, diesel) fuels in machines and engines, the LFS must be of adequate quality. 

The European Union has names for this called EURO 2 or EURO 4, which are all standards of clean fuel. but even if we have talks about shifting to euro 2 or euro 4 we don't have any actions to back up the talks. So, we first need to maintain a standard for clean fuel, even though India is using these standards. Secondly, we mentioned a big source is industry. 

Every place in the world has industries, we are not the only industrially developing country. Even in Europe and America, they have had industries for a long time so why aren't they facing such pollution levels? It is because they are controlling their pollution in two ways. First, by improving the machine mechanics of the industries to design them in such a way that will ensure lower pollution levels. Secondly, the pollution that is getting formed isn't allowed to enter the normal ambient atmosphere, they are filtering and treating it to make it clean. In these ways, we must control industrial pollution as well. 

Thirdly, we need to improve our technologies in brickfields and kilns. The technology we currently have is very old (FCK) because it is very polluting. we must shift to modern technologies which, even if it won't stop pollution, will greatly reduce it. 

Another note is we are making houses with bricks, we should search for alternative housing materials. The gov planned for something like this but isn't going into action for it, but we must go into this and change the architectural design as well to reduce the brick demand. 

Thirdly, we can reduce pollution for construction activities. We can often notice how one agency will cut a road, then another will come in to fill it up, followed by another which will rebuild it. This is a great incoherence, and all the agencies involved in this job need to coordinate between themselves so that this isn't done over and over again and road development can be completed in one working so that pollution will decrease. The more exposed dust and dirt that is laid in front of homes to be promptly used by road development aren't in our law either. The brick, cement, and rods that they are storing aren't in our rule, but they are keeping it along roadsides and working with it, which causes a lot of pollution too. Big construction sites must be covered up. In Europe and America, during construction activities, the dust and noise aren't allowed to disturb the next house, but we cannot even sleep properly because of this, at 3 am even trucks come in and dump rods. 

Another point is enforcement, even if we don't have the rule we must implement those but enforcement is a very weak spot too. We need to give more effort to increase that and give more manpower to the agencies to make them more effective and active to reduce pollution. 

The fourth point, biomass burning. The biomass burning causes a lot of pollution and the houses are always small and less ventilated even though children and elderly people are living there. We must improve this infrastructure so that pollution is reduced and ventilation is ensured so the pollution can exit. Otherwise, we can shift to electric ovens or gas so that pollution is reduced. These are all direct methods, another method is indirect action. For example, our towns are not planned properly. Infrastructure is developed continuously but plans always have a set ratio of the number of parks, water bodies, trees, houses, etc in an area and that area is very imbalanced for us. We are not maintaining it, and trees are being reduced by the days which is increasing pollution. The plans must be adequately designed to ensure a balance in trees, greenery, and water bodies. 

Finally, I will say that we must create awareness among our citizens so that we can avoid polluting on a perennial, daily level. We must always think about whether our everyday actions are causing pollution, and if it is, how can we minimize this. The industry owners must be aware of their actions as well and do something about them instead of ignoring them. Like the example I said earlier, a report earlier showed that some late-night industries recycle batteries by using hydrochloric acid sulphuric acid which forms a lot of smoke. They're not maintaining the air pollution concerns but using these cheaper methods since it increases profits. They are personally gaining money but harming the country in the process. So an awareness program is required and we must alert the poor and rich, young and old, everybody about air pollution. If we ensure everything I just mentioned then we can hope for a nice pollution-free country in the next few years.

Shamir: This is very excellent! Thank you so much. I would like to highlight one point you have mentioned, most of the time we talk about outdoor air pollution but indoor air pollution is also a huge issue. Prof Salam, you spoke about clean cooking stoves, in the village areas the majority of the stoves are conventional burning although recently a lot of places has seen an improvement and this is a major issue. I also want to repeat the two points you mentioned at the beginning since they are important, firstly we must create the evidence to base the policies for the policymakers. The things we spoke about here like transboundary air pollution and sources of air pollution, we truly need a scientific understanding so that the policies can be made properly. The second point I would guide to policymakers is that recently Bangladesh's nationally determined contributions under the Paris agreement submitted to the UNFCCC, this NDC, and other national policy documents must have an integrated approach since air pollution is not a standalone issue. As you mentioned how fuel is a source, then all policies must jointly address their decisions to come to a proper unanimous conclusion. The second topic I want to know from you, I know you are not a legal expert but recently in 2019, Bangladesh drafted a Clean Air Act. What is the state of this plan and what is the legal instrument? As you mentioned, enforcement is a huge issue, so if you could tell us about these issues and the efficiency of legal instruments of the Clean Air Act.

Salam: Thank you. So when this was in its drafting stage I had the chance to read it once to give my input. I wouldn't say the Clean Air Act is 100% foolproof, but if it is implemented, we will achieve more robustness in law enforcement. So the faster it goes into implementation, the better it is for us. This has been ongoing for the last three years but for reasons I don't know the act has not seen the light of day yet, but the existing rules are already good but this will be even better for the enforcing agencies and us. However, I must also bring up, are our existing laws being properly followed in the first place? we must see this. Like we have laws against filling water bodies, cannot obstruct the roads for construction, garbage management, but these have not been stopped, or no effective measures have been taken against them. It is possible to tackle these with our existing laws but it is still not happening, and we must also see why right now.

Shamir: Thank you. Can you tell the audience a few of the recommendations you gave for the draft?

Salam: I don't remember at this moment, but I commented on the different guideline values from the chemical side, not on the legal aspect as that is not my expertise. So what I commented on was our guidelines, say for PM2.5 compared to the WHO values, how much industries are producing, and so on. 

Shamir: Alright, thank you. Do you have any final thoughts, comments, or additions about air pollution overall?

Salam: What I want to say overall is that pollution has happened in a lot of countries worldwide and they were able to solve the issue. Now we do have pollution, which people are talking about, so we will also see a solution soon. For this reason, both government, non-government institutes, and organizations should all contribute, however they can, to improve the problem as soon as possible since a whole nation cannot live in such polluted conditions. I believe that this problem will be solved as there are a lot of global agreements and policies which always include Bangladesh in their plans. Bangladesh is one of the main eight founding members of the CCSE. So, Bangladesh has a huge role and I believe that not only for air pollution, but also for how much water we can safely drink from which of the polluted 254 rivers of our country, and our overall environment will be very improved, I hope. 

Shamir: Thank you. Now at this very end, I would like to know about two things. First is how COVID has impacted all of us in some way. The research and work you have done during this covid time, out of this did you start to pursue some bigger hobbies or interests?

Salam: Personally, after covid, many of my activities have become limited as I would go out a lot before. But in the academic line, we have published many scientific papers during this time in good journals, which I didn't get the time for before because of having to commute to class or run errands and be stuck in traffic for hours. Now I am home and can write a lot in this line to do more research. I would say that thanks to covid my writing habits have gone up compared to before.

Shamir: Excellent. So would you like to recommend any book or studies for our audience which can help them gain in-depth knowledge and understanding on this issue?

Salam: I and my colleagues worked on a study about how we can protect school children from air pollution in collaboration with some people from England and released a book about this in 11 different languages. If people read the book, they can understand how to decrease air pollution and protect children from it. This is in 11 different languages and my three students and I have worked on the Bangla edition. I can share it with you, it is available on my researchgate and my website. 

Shamir: Okay, great. Can you tell us where people can find you if they want to know more about your work and research? If you have some social media accounts?

Salam: I have accounts everywhere, be it Facebook, Twitter, LinkedIn but the best source would be to go to the Dhaka University website and click on the publication section since I post all my latest publications in that section, even the one that came out a few days ago. You simply have to type "Abdus Salam Dhaka University" and click on the website that shows up, all my details can be found there. I can share it with you if you want.

Shamir: Yes, of course. We will put all these details in the podcast show notes for our audience, and we will also put a link to all your research and publications there. So, Professor Salam, it was a fascinating discussion, it was very eye-opening for me, and hopefully, our policymakers and everyone who is working on this issue will be enlightened from this discussion as well. Once again Professor Salam, thank you immensely on behalf of Our Common Future podcast for joining us.

Salam: Thank you and your audience a lot for giving me the opportunity to speak here.

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