Environmentally sustainable urban transportation--comparative analysis of local emission mitigation strategies vis-a-vis GHG mitigation strategies

This study presents the comparison between global emission mitigation strategies (GEMS) and local emission mitigation strategies (LEMS) and their potential in controlling the non-target pollutants/emissions in concurrence with their economic performance. Comparative analysis revealed that strategies targeted at the mitigation of local pollution like total suspended particulate matter (TSP) and hydrocarbons (HC) also shows greater potential in reducing carbon dioxide (CO2) emissions (as non-target emission). In GEMS, 20% CO2 reduction resulted in 14.9% reduction in TSP emission. In LEMS with a 20% TSP reduction, CO2 emission reduction was found to be 15.2%. TSP mitigation strategy not only performed well with non-target global emission but also within local emissions with SOx reduction much higher than that of target pollutant (TSP itself). The HC mitigation strategy was found to be under-performing with most of the non-target pollutants lying far below the target pollutant reduction. The total cost of transportation is found to be in a similar and smaller band across all strategies (both GEMS and LEMS). The HC mitigation strategy resulted in the least cost followed by the CO2 and TSP strategies. TSP strategy of emission reduction while planning the transportation system for a longer period was found more effective than GHG mitigation strategy. Therefore, employing local pollutant mitigation strategies in transportation planning would also cater for the needs of GHG mitigation, which is a key factor in attracting international funding organizations to invest in transport infrastructure development in developing countries. It would also provide equal consensus from local policy makers, environmental activist and also global actors. This presents a base for the argument that the transportation projects need to be looked at in pollution mitigation approach rather than the GHG mitigation approach.