Assignment: Air Pollution on Dhaka
City
NAME
: MD. Mubarrat Bin Islam
ID
: 1920571
SEMESTER
: Spring 2020
COURSE NAME
: ENV101
Section
: 07
INSTRUCTOR
: Ms. Karishma Sinha
CONTENTS
Introduction: ..................................................................................................................................................................2
Air Pollution: ..................................................................................................................................................................2
Problems of Dhaka City: ................................................................................................................................................3
Air Pollution in Dhaka City: ............................................................................................................................................3
Effect of Air Pollutants on Human Health: ....................................................................................................................4
Conclusion: ....................................................................................................................................................................4
References: ....................................................................................................................................................................5
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INTRODUCTION:
Air pollution is one of the man made environmental disaster. Air pollution defined as an
atmospheric condition in which various substances are present at concentrations high enough
above their normal ambient levels to produce a measurable effect on people. “Substances” refers
to any natural or manmade chemical elements or compounds capable of being airborne. These
may exist in the atmosphere as gases, liquid drops, or solid particles. It includes any substance
whether noxious or benign; however, the term ‘measurable effect’ generally restricts attention
to those substances that cause undesirable effects. Air quality has deteriorated both due to
human activities, and natural phenomenon such as wind blown dust particles etc. There are two
major sources of air pollution in Bangladesh, vehicular emissions and industrial emissions.
However, these are mainly concentrated in the cities. Recently, air pollution has received
Exposure to air pollution is the main environmental threat to human health in many towns and
cities. Particulate emission is mainly responsible for increased death rate and respiratory
problems for the urban population. This problem is acute in Dhaka being the capital of the
country and also the hub of commercial activity. Dhaka is a major, cultural, and manufacturing
center. The common types of industries in and around the periphery of Dhaka are ready-made
garment manufacturing, jute, tanneries, textile, tea processing, fertilizer, cement, paper and
pulp, chemicals and pesticides, food and sugar, pharmaceuticals, petroleum refinery, distillery,
rubber, plastics, and brick manufacturing, assembling buses, trucks, and motorcycles, assembling
radios and televisions. Air of Dhaka is being polluted day by day very badly. The other urban areas
such as Chittagong, Khulna, Bogra priority among environmental issues in Asia, as well as in other
parts of the world. and Rajshahi have much lesser health problem related to urban air pollution.
The ambient atmospheric conditions have progressively deteriorated due to the unprecedented
growth in numbers of motor vehicles, and continuous housing and industrial development.
AIR POLLUTION:
Contamination
in
the
atmosphere caused by the
discharge,
accidental
or
deliberates of a wide range of
toxic substances. Often the
amount
of
the
released
substance is relatively high in a
certain locality, so the harmful
effects are more noticeable. The
major sources of air pollution are transportation engines, power and heat generation, industrial
processes and the burning of solid waste. A new source of air pollution is an increasing 'hole' in
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the ozone layer in the atmosphere above Antarctica, coupled with growing evidence of global
ozone depletion. Air pollution has also long been known to have an adverse effect on human
beings, plants, livestock and aquatic ecosystem through acid rain.
PROBLEMS OF DHAKA CITY:
Bangladesh capital Historic Dhaka is fast turning into an inhabitable city. Air and water are
saturated with poisonous elements, sound pollution reaching unacceptable limits, gas electricity,
and water supply crisis looming large, rapid depletion of subsurface water level making the city
vulnerable to mild earth quake. Dhaka city is expanding in all direction east to west, north to
south, population is increasing in geometric progression but the civic amenities cannot keep pace
with the growing demand. The capacity of various utilities can no longer meet the rapidly
increasing demand. Supply of pure drinking water, safe accommodation for the growing
population, appropriate sanitation, municipal waste collection, supply of electricity and gas for
about 150 Million city dwellers are progressively turning into serious crisis. In this serious
situation the news about Dhaka city air reported to containing higher proportion of lead and CO
must be considered very alarming. Serious noises, unacceptable sound level is causing hearing
problem. In no modern cities these days the automobiles blow horns in the heart of the city. The
water of rivers around Dhaka city is nothing but poison. Even WASA Water treatment plant in
Salemabad finding it very difficult to treat the poisonous water of Sitalakya. But the helpless
shelter less people from villages and rural people are migrating to Dhaka compounding the
problem still further. City dwellers are already affected with various contagious water borne
disease. Dhaka has already turned into a slum of concrete.
AIR POLLUTION IN DHAKA CITY:
There are two major sources of air
pollution in Bangladesh industrial
emissions and vehicular emissions. The
industrial sources include brick kilns,
fertilizer factories, sugar, paper, jute and
textile mills, spinning mills, tanneries,
garment, bread and biscuit factories,
chemical and pharmaceutical industries,
cement production and processing
factories, metal workshops, wooden
dust from saw mills and dusts from ploughed land, and salt particles from ocean waves near the
and coastal lands. These sources produce enormous amount of smokes, fumes, gases and dusts,
which create the condition for the formation of fog and smog. Certain industries in Bangladesh,
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such as tanneries at Hazaribag in Dhaka City, emit hydrogen sulphide, ammonia, chlorine, and
some other odorous chemicals that are poisonous and cause irritation and public complaints.
This may cause headache and other health problems. With increased rate of urbanization in the
country, the number of vehicles is also increasing rapidly, and contributing to more and more air
pollution. The Department of Environment (DOE), and other related organizations, have
identified the two-stroke engines used in auto rickshaws, motorcycle, mini-trucks, and
motorcycles as major polluters. According to BRTA, there are 469888 motorcycle, 247324 private
cars in Dhaka City alone. Moreover, overloaded, poorly maintained and very old trucks and minibuses are also plying the city streets emitting smokes and gases. In fact, about 90% of the vehicles
that ply Dhaka's streets daily are faulty, and emit smoke far exceeding the prescribed limit. Diesel
vehicles emit black smoke, which contain unburned fine carbon particles.
EFFECT OF AIR POLLUTANTS ON HUMAN HEALTH:
Carbon di-oxide (CO2): It is a major absorber of infrared radiation emitted towards the space
from the earth surface. Thus, it has crucial role in planetary temperature structure.
Carbon monoxide (CO): If inhaled, it is absorbed from the lung alveoli 300 times faster than
oxygen. High concentration of CO in blood makes it difficult for heart to pump blood through
arteries.
Hydrocarbons (HC): Unburnt hydrocarbon may form ozone with oxides of nitrogen which is a
central nervous system depressant. Other hydrocarbons cause convulsion of CNS.
Oxides of nitrogen (NOx): Causes dilatation of air spaces in lungs. NO2 causes damages to
bronchioles and alveolar ducts. NO2 is also suspected to impair the defense mechanism of
respiratory system. Infants and children are more susceptible.
Particulate matter: Diesel emits suspended particulate matter (SPM) which contains shoot.
Shoot is responsible for reduction of atmospheric visibility and absorb and carry organic
compound to lungs.
Lead (Pb): Around 75% of the ingested lead is deposited in bones and tissues causing irreversible
brain and kidney damage. Growing nervous system of young children are particularly vulnerable.
CONCLUSION:
Dhaka is a mega city. And it is overcrowded capital city of Bangladesh. Dhaka has been grappling
with air pollution for a long time. The air quality generally worsens during summer and shows
signs of improvement during monsoon. Air pollution severely affects health and is a rising cause
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of death. At least 123,000 people have died in Bangladesh in 2017 due to indoor and outdoor air
pollution.
REFERENCES:
1.
2.
3.
4.
https://www.stateofglobalair.org/sites/default/files/soga_2019_report.pdf
https://www.stateofglobalair.org/report
https://www.thedailystar.net/backpage/dhaka-air-quality-unsafe-1823263
https://www.dhakatribune.com/bangladesh/dhaka/2020/02/09/dhaka-ranks-worst-inair-quality-index-2-2
5. https://brta.portal.gov.bd/sites/default/files/files/brta.portal.gov.bd/monthly_report/c
6b00557_49aa_412d_b2e3_5b1409db3152/Dhaka%20Metro.pdf
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