On-Road Vehicular Emission Inventory in View of Its Distribution Over Dhaka City, Bangladesh: A Bottom-Up Modelling Approach to Support Sustainability Assessment

Abstract

The study aims to account emissions from the vehicular sources of Dhaka city, more specifically, for the major roads of the city. Transport sector being one of the highest contributors of air emissions in the city makes it important to investigate the factors that catalyse the on-road emissions and acts as constraints in attaining environmental sustainability. Due to several reasons, on road congestion level is very high in the city that reduces the fuel efficiency of the vehicles. The research tends to reflect the fact while accounting the emissions with a meso scale bottom-up modelling approach, where the road by road vehicle characteristics are considered. The study estimated emissions of criteria pollutants, greenhouse gases and toxic substances by adopting a bottom-up technique to cover the major roads of the city in the current state of operation, where the actual moving pattern of the vehicles on different city roads were considered. Detailed survey was conducted in the Dhaka city roads in the year 2012 to collect diurnal traffic volume, speed profiles and vehicle composition. In general, the results suggested that the roads with higher traffic volume coupled with traffic congestion contributed at a higher rate to the emission load. The increasing trend of private vehicles along with uncontrolled traffic movement keeps the city under the threat of the harmful level of emission if proper management strategy is not adopted. As considering the detailed system-data can offer greater proximity to identify the key areas of concern, the methodological approach of this research can be adopted by others as well concerned with the on-road vehicular emissions, and can work towards attaining sustainability by reducing emissions and increasing fuel efficiency.

Keywords: Emission inventory; bottom-up modelling; vehicle speed profile; Dhaka city, Bangladesh