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Air pollution : Mass Killer in Dhaka City

Dhaka, the capital city of Bangladesh has a population of about 9 million that is projected to grow to about 16 million by year 2015, making it the seventh largest mega city in the world.
That phenomenal growth has far outstripped the capacity of its urban transport system. Traffic congestion is part of daily life in Dhaka, vehicle-related air pollution is growing at an alarming rate, and traffic delays have tripled in the last three years.

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.

Present situation of Dhaka

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.

Air Pollution

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.


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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