Bangladesh is a country located in the southern region of Asia. It has seen in recent years amassive amount of economic growth as well as a population boom, with some 162million or more people calling Bangladesh their home. This makes it the 8thmost populous country worldwide, with a close proximity to other countries suchas Myanmar, India, Nepal and China, many of which suffer from their ownpollution related issues, with the economic giants of India and China takingmany of the top spots in regards to most polluted cities across the globe.
Observing the pollution readings taken over the last few years, it is clear to see thatBangladesh has some fairly severe issues with its pollution levels, so much sothat it actually takes the number one spot out of the most polluted countriesranked worldwide, along with its capital city Dhaka taking the 21stspot in terms of most polluted cities ranked over 2019. These are positionsthat indicate that Bangladesh has a pollution crisis in its hands.
Once again in 2019, Bangladesh as a country came in with a PM2.5 reading of 83.30 μg/m³, thatas mentioned put it in 1st place. This reading would also place itinto the middle to higher end of the ‘unhealthy’ ratings bracket, whichrequires a PM2.5 reading of any number between 55.5 to 150.4 μg/m³ to beclassed as such. PM2.5 refers to any fine particulate matter that is 2.5micrometers or less in diameter, and due to its extremely small size has ahighly negative effect on the health of anyone who breathes it. As such it isone of the major components used in the calculation of overall pollutionlevels, with other pollutants such as PM10 and ozone (O3) beingfigured into the equation as well.
Whilst there would be many natural areas of pristine beauty and clean air around Bangladesh,particularly in rural areas, the extremely poor placing in terms of itspollution levels is due to major cities such as Dhaka. With the rise of rapidurbanization often comes a massive influx of rural to city migration, which hasa compounding effect on the pollution levels.
Growth in the population comes with an increase in cars, larger demand for homes as well as aboom across all industries. As mentioned, whilst there would be many areas ofBangladesh that do not fall under these terrible ratings as a whole, thecapital city is of prime focus for the country’s pollution levels, and with itsgrowing population, a solution to these disastrous levels of smoke, haze andpollutants in the atmosphere must be addressed.
Whilst Bangladesh sees many sources of pollution, there are several that stand out asbeing main instigators in the awful levels of pollution seen. In the mostsimplistic take on pollution causes, which is not only native to Bangladesh butan eternal problem worldwide, is that of vehicle usage. With a vast amount ofcars, motorbikes, buses and trucks dominating the roads, it is inevitable thatlarge amounts of pollution are going to be emitted from these in the form ofexhaust fumes.
Of note is that there is a distinct lack of regulations regarding the state and quality ofthe engines and motors that can be used, and as such in a similar fashion toother highly polluted countries such as Nepal, there are many cars, motorbikes and buses thatare kept in use long after they should have been taken off the road. Theseancient machines, running on fossil fuels such as diesel, spew out largeamounts of black soot, sulfur and other toxic compounds and gases that allcontribute to the high levels of year-round ambient pollution, far much more sothan a cleaner or less ancient counterpart would.
Besides the vehicular emissions, Bangladesh also has its industrial fumes to worry about,with heavy concentrations of both factories and small-scale local businessesoperating within the cities. Of particular salience is that of the brick kilns,with cities such as Dhaka being famous for its high output of bricks, producingestimated numbers of well over a billion bricks per year.
These kilns, often run by small scale family-based operations (although extremely high innumber across the cities) rely on the burning of materials such as coal, woodand any other combustible items that can be obtained, such as black rubbertires or synthetic materials such as plastic, which release heavy amounts ofhighly toxic black soot.
Besides the heavy use of these kilns, often referred to repeatedly in media outlets becauseof their heavy pollution contributions, along with public acknowledgement thatit is doing so (with no proper enforcement or punishment yet in sight foroffender), there is also the problem of dust accumulation within the city,something that is not normally acknowledged as a pollutant, but with highlevels of PM2.5 and PM10 finding their origin from the various types of finelyground dust, they are also a large contributing factor to Bangladesh's airquality problems.
So, to summarize, the main causes of pollution in Bangladesh are vehicular emissions,fumes from factories and brick kilns, as well as dust accumulations fromvarious sources, all of which will be discussed in further detail.
To address the emissions given out by the various kinds of vehicles first, they wouldinclude the standard ones such as carbon monoxide (CO), ozone, nitrogen dioxide(NO2) and sulfur dioxide (SO2). Out of all of these,nitrogen dioxide would see the most prominence in the atmosphere over any givenarea that sees a high level of traffic or large volume of vehicles movingthrough it, particularly at peak times such as rush hours or mass commutes inand out of the cities. Nitrogen dioxide is so pertinent in its release fromvehicles that its concentration in the atmosphere can often be used todetermine exactly how much pollution is being caused by traffic alone.
Besides the standard vehicle pollutants mentioned, when diesel fuel comes into the equationthe aforementioned chemical compounds are often released in far greaternumbers, accompanied by other dangerous pollutants such as black carbon andvolatile organic compounds (VOC’s). Among the VOC’s you would find chemicalssuch as benzene, formaldehyde and methylene chloride. All of these have adverseeffects on human health, and a tendency to become gases at room temperature,making them more dangerous as in their gaseous form it is far easier torespire. The volatile aspect of their name refers to this property ofevaporating into a gas at a much lower temperature.
Black carbon is also found released alongside the aforementioned chemicals, as well as beinga major component in soot, being released in large volumes from the burning ofwood, coal and various types of organic refuse. It has many damaging propertiesupon inhalation, including increased rates of cancer, scarring of the lungtissue as well as damage to the heart due to its ability to enter into theblood stream via the lungs.
Besides this it also has a number of disastrous consequences on the environment and climate,as well as affecting the temperature within a city, having knock on effects onthe quality of people's lives, showing just how far reaching and insidious allforms of pollution are.
Black carbon has the unique property of being able to absorb solar radiation and release itas heat, and with large accumulations of this taking place due to its heavyrelease from factories, brick kilns and automobiles, it would be found in high amountspermeating both the atmosphere and roads across Bangladesh.
Other pollutants that would be released from the combustion of the kiln firematerials would include furans, dioxins, lead and mercury, polynuclear aromatichydrocarbons and polychlorinated biphenyls. All of these have disastrouseffects on the health of humans, wildlife and vegetation.
With the plethora of previously mentioned pollutants and fine particulate matter in theair in Bangladesh, there come along with it a large number of health issues,most pertinent when the pollution levels are at their highest (such as inJanuary and December in Dhaka with their readings of 181.8 μg/m³ and 146.3 μg/m³respectively), although of note is that even at lower concentrations ofpollution there will always be a risk for adverse effects.
Amongst vehicular pollution, with pollutants like nitrogen dioxide and carbon monoxidebeing prominent in the atmosphere, symptoms such as irritation to mucousmembranes such as the mouth, inner nose, eyes, throat and stomach becomepossible. There also becomes a risk for increased bouts of chest infections,that lead to further susceptibility to respiratory conditions such as influenzaand pneumonia.
When exposed to PM2.5 and PM10 arising from both fires as well as fine dust accumulations,rapid aging of the lungs can occur, with their capacity being reduced due toscarring as well as the alveoli, or small air sacs in the lungs becoming filledwith PM2.5, lowering its ability to fully take in oxygen and pass it over thebloodstream unabated.
With a shortness of oxygen available to the body, side effects such as ischemic heartdisease become possible, something that occurs when an organ fails receiveenough oxygen to keep the tissues at a healthy and full functioning level. Thiscan in turn have knock on effects of increased rates of heart attacks,arrythmias, strokes, problems related to blood pressure and an overall increasein mortality rate.
As mentioned, the extremely small size of PM2.5 allows it to find its way into the air sacsof the lungs, whereby it can accumulate and cause increased risks of lungcancer (as well as the decrease in full lung function), but in other instancesit can actually cross over the blood barrier via the lungs and makes its wayinto the bloodstream and to every part of the body via the circulatory system.
This can wreak havoc on the human body, with all organs being susceptible to damage, inparticular those that have filtration roles such as the hepatic and renalsystems (liver and kidneys). Damage to the blood vessels can also occur, aswell as other areas of the body such as the reproductive system being affected,having ruinous effects on fertility rates and reproductive health as a whole.
Young children who are exposed to high levels of pollution can end up withdevelopmental problems due to pulmonary issues, which can stunt growth as wellas cause cognitive impairments. Once children suffer from multiple bouts ofrespiratory illnesses such as pneumonia, not only does the child mortality ratego up, but the chance of them having lifelong issues related to the health oftheir lungs and an increased susceptibility to further respiratory ailmentsgoes up.
Pregnant mothers are also highly vulnerable to pollution levels, with disastrous effectson their unborn babies occurring. Instances of miscarriage or stillbirth go upsignificantly (thus adding to the infant mortality rate in Bangladesh), as wellas chances of the child being born severely underweight, or prematurely. Assuch it is important to highlight the large number of health risks that canhappen to every part of the population, and preventative measures becomeincreasingly important, such as the wearing of high-quality air filtering masks, as available onsite, as well as staying up to date on pollution levels on any given date viaair quality maps, available on the AirVisual app as well as the IQAir website.
Whilst it may seem a daunting task that may require years of collective work from both thegovernment and citizens, dents may be put into the levels of pollution via theimplementation of fines and punishments for those that exceed air pollutionlevels in any given areas, whether they are large scale industrial factories orsmall-time brick kilns operated out of a family home or shop. Education is alsoparamount in this, with the educating of the general population to thedisastrous effects of pollution so that they may reconsider the materials thatthey burn before doing so.
Others would include the eventual removal of ancient vehicles off the road, as well as amove to cleaner fuel sources and phasing out of diesel fuels in automobilesacross the country. As stated, a highly concentrated effort would need to takeplace over the coming years, if Bangladesh is to see its position as worldsmost polluted country changed for the better.