Towards mitigation of vehicular emmission through roadside trees in Dhaka city: a GIS based simulation approach

Abstract

Vehicular emission is the major source of air pollution in Dhaka city. On the other hand, trees are important element of environment for providing pollutant free healthy atmosphere. Roadside trees are important as they are directly exposed to the vehicular emission sources and might help to reduce automobile pollution by sequestering them. In this study, carbon dioxide (CO2) emission along major roads of Dhaka is investigated during daylight time of weekdays and mitigation of CO2 by greeneries along those major selected roads have been determined. Daylight hour traffic volume has been considered to estimate emission because CO2 absorption process by greeneries is activated only with the presence of sunlight. For the detail analysis the selected major roads have been divided into four major routes viz. Mirpur Road, Pallabi to Gulistan, Kuril to Bijoyshoroni and Kuril to Shegunbagicha. It has been found from the analysis that existing roadside trees can sequester only 9.49% of total vehicle emitted CO2 during daylight hour of a weekday. About 90.51% of vehicle emitted CO2 stay within the air of Dhaka’s major traffic area. The quality of traffic environment is thus in very alarming position and indicates requirement of more greeneries to mitigate air pollution. Up to the year 2040, future traffic volume and their induced emission have been simulated using Geographic Information System (GIS). To take a priori measure mitigating pollution in future, the required numbers of greeneries have also been estimated through simulation process. The findings thus obtained in this study allow recommending some significant aspects of traffic environment.