Vehicles
constitute the dominant source of air pollution in Dhaka. Two categories
of vehicles making significant contributions to overall fine particulate
emissions are two-stroke engine three-wheelers and heavy-duty diesel
vehicles. As vehicle ownership and use are growing rapidly, the need
to initiate pollution control activities is urgent. A large number of
pedestrians, drivers, passengers, traffic policemen, street vendors
and other groups undoubtedly suffer from significant health damage as
a result of exposure to emissions from a large variety of motorized
vehicles including two-stroke auto rickshaws or "baby taxis", trucks,
buses, cars and two-wheelers. They are responsible for 25% of the particulate
matter and 60% of the toxic and smog-forming hydrocarbons contributed
by all motor vehicles.
Major issues are the two stroke engines moving in Dhaka's street, heterogeneous
flows of traffic and our continued and growing reliance on the private
car. It is not out of subject to mention here that the two-stroke engines
(Baby taxis) moving in Dhaka city are simple modified form of an Italian
model of 1960's. It is estimated that a baby-taxi emits 30 times more
pollution than a normal car. In providing a very simple logic, we can
replace a baby taxi by 30 cars in Dhaka, considering the environmental
point of view. Though baby-taxi size is a suitable mode for Dhaka's
street geometry.
As
the road facilities have not been developed in the same pace of
population and size, the city is notorious for traffic jams everyday
with the resultant effects of concentrated vehicular emissions.Apart
from the problem of vehicular emissions, there are a number of
other factors significantly contributing to the worsening air
quality in the country, which include industrial emissions, bad
civic practices and poor municipal services.
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Emission inventories
of NOx and SOx have usually been made on national basis mainly for general
administrative purposes and public information, systematic data published
for the use of the scientific data is rather scarce. Nationwide SOx and
NOx were calculated based on sulfur content and statistics of fuel consumption
estimates of emission factors specific to individual source categories
over time.
Developing
countries like Bangladesh is characterized by a rapid increase of energy
consumption accompanied by a rapid growth of population and economic
activities. Thus the increasing contribution of atmospheric loads of
SO2 and NOx to global climate change is anticipated and it is really
necessary to quantify these emissions in a hurried manner. A national
steering committee should establish with local and expatriate Bangladeshi
experts to deal with the problem.
Rapid vehicular
growth in the metropolitan areas of Bangladesh in recent years has been
accompanied by an associated increase in emissions of harmful pollutants.
The exposure of the public to air pollution in Dhaka is estimated to
cause 15,000 premature deaths and several million cases of sickness
every year. The poor are particularly vulnerable to air pollution, due
to above-average physical exposure to air pollution; furthermore, impoverished
children suffer from additional effects of air pollution due to malnutrition.
Air pollution levels in Dhaka are considerably higher than Bangladeshi
standards or World Health Organization (WHO) guidelines for residential
areas. Greater exposure to particulates has been linked to premature
deaths from respiratory and cardio-vascular illnesses, and higher rates
of sickness, especially bronchitis and other chronic obstructive pulmonary
diseases, as well as respiratory tract infections. Other physical impacts
of air pollution include damages to crops and ecosystems, degraded visibility,
soiling of buildings, and damage to water quality through deposition
of lead and other pollutants. These effects on the ecosystem impair
people's livelihood as well as health.
According
to a study of World Health Organization, blood lead level above
10 g/dl (microgram per deciliter) is considered to be a case of
lead poison. However, the lead level in the country's urban children
was 5.8 to 21.6 g/dl, and the urban slum children 's lead level
ranged from 9.6 to 38.9 g/dl, three times more than the acceptable
level.
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The
increasing air pollution is impeding Bangladesh's development and it
is indeed a matter that should be addressed seriously. It is not only
the health cost that is going to be enormous and burdensome on the national
exchequer, but the loss of potential working ability of the people due
to poor health conditions, experts observed.
In Bangladesh, pollution severity occurs due to the high content of
lead in gasoline, large number of high polluting vehicles, impure fuel,
inefficient land use, and overall poor traffic management. The pollutants
of concern for Bangladesh are leaded fuel, particulate matter, dust,
oxides of nitrogen, and sulfur dioxide.
In the face of the problem, the Dhaka city corporation and the Bangladeshi
government have launched a plan to reduce the traffic problems that
have reached crisis proportions in the nation's capital.
To fight the air pollution in the country, the World Bank, the United
Nations Development Program and the Bangladeshi government have already
come up with serious thoughts and taken some concrete steps.
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References:
»
BBS (1996) Statistical Yearbook of Bangladesh, Bangladesh Bureau of
Statistics, Government of Bangladesh
» Md. Masud Karim, Ph.D.Consulting Engineer,Dainichi Consultant
Inc., 3-1-21Yabuta Minami,Gifu 500,Japan
»
Chen Jian, Xinhua General News Service, 7 February 2001
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