Abstract:
Dhaka, the capital city of Bangladesh, with a population density of around 20,000 per
square kilometer is at the risk of experiencing significant health impacts from poor air
quality, especially during the dry season. The economic cost associated with urban air
pollution is estimated to be around 1.1% of national GDP.
Recently, the Government introduced a number of initiatives such as banning of twostroke
engine vehicles, promoting the use of alternative fuels like CNG, banning of old
vehicles from plying on streets, in order to curb the growing air pollution problem.
Though some improvements have been observed, such policy decisions are taken on adhoc
basis and there is a lack of benefit modeling to support these decisions due to
limited monitoring and limited analysis of the options.
Currently, the institutions lack an integrated policy analysis tool to help the decision
makers evaluate alternate air pollution management strategies and analyze costs and
benefits. This research aims to fill this gap, by developing a policy analysis tool for
Dhaka to better understand the impact of various abatement measures and potential for
environmental benefits. The tool is designed to follow the impact pathway approach
linking the changes in emissions with changes in ambient concentration, especially
particulate matter (PM) and related health impacts - mortality effects and the associated
monetized benefits.
A grid based source-receptor matrix over Dhaka has been developed using an
atmospheric dispersion model, considering temporal variations in emissions and
weather parameters round the year. The contributions from major sources (vehicles, and
brick kilns) have been considered in determining the ambient PM concentrations; both
spatial and temporal variations of PM have been estimated. In the Dhaka city the PM10
concentrations in dry season has been estimated to be less than 50 μg/m3 to about 150
μg/m3. The range of PM2.5 concentration in the city has been estimated in between 25
μg/m3 and about 65 μg/m3. Near the National Parliament Building, where CAMS (air
quality monitoring station) is located, brick kiln has been found to be the major source
of particulate pollution with 43% contribution to PM10 concentration and 21%
contribution to PM2.5 concentration. Traffic pollution contributes 10% to PM10
concentration and 13% to PM2.5 concentration at that specific site. However, the sourcereceptor
matrix could be easily utilized to obtain ambient concentrations as new sources
are added/removed from the domain.
Particulate related health impacts have been evaluated utilizing established
concentration-response functions for mortality due to pollution exposure. Moreover, the
monetary value of these health impacts due to traffic and brick kiln emissions are
estimated. Finally, the study presents case studies under “what-if” scenarios for multiple
policy alternatives using the developed policy assessment tool for Dhaka. It has been
found that significant health and economic benefits could be achieved with policy
interventions aimed at improving air quality.
