Emission characterisation of motorcycles and the potential of co-benefits from selected development scenarios in the urban ecosystem of Hanoi, Vietnam

Abstract Motorcycles are the largest proportion of transport in Hanoi. This study focuses on the emission characteristics and initially evaluates the potential co-benefits of low emission zones (LEZ) applied to motorcycles in Hanoi. The International Vehicle Emissions (IVE) model was designed by the U.S. EPA to calculate emissions from motor vehicles and was used to find the emission factor, the important index for emission characteristics of motorcycle activities, in Hanoi. This study surveyed motorcycle technologies and activities in Hanoi with questionnaires, collected data from GPS devices, and counted traffic flow through video cameras and collaborators teams from 2021 to 2023. EFs for the typical pollutants and GHGs of motorcycles in Hanoi were determined. During running, EFruning is 0.053g/km with PM, 4.8 g/km for CO, 0.006 g/km for SO2, 0.13 g/km NOx, CO2 is 72.55 g/km and CH4 is 0.24 g/km, respectively. When starting, EFstart-up is 0.12 g/time with PM, CO is 12.24 g/time, SO2 is 0.0007 g/time, NOx is 1.05 g/time, CO2 is 6.96 g/time, CH4 is 0.53 g/time and N2O is 0.0009 g/time, respectively. Using the EMISENS model, inventory emissions were calculated at tier 3 for this source via the Bottom-up approach. The EMISENS model calculates emissions resulting from traffic, developed by Bang Ho et al in 2010 uses input data related to traffic activities and three emission factors found from the IVE model to calculate the emissions. The total emissions from motorcycle operations in Hanoi are approximately 5.3 thousand tons of PM and 4.6 million tons of CO2e. The proposed LEZ solution for motorcycles brings climate co-benefits of reducing 1.62 million tons CO2e in scenario 1 - limiting all day and 563.2 thousand tons CO2e in scenario 2 – limit operations from 3:00 p.m. to 8:00 p.m. in 2025. Co-benefits on the environment corresponding to the two scenarios with PM are 1990 and 692 tons. Reducing motorcycle operations during 5 peak hours at LEZ can reduce total emissions from motorcycles in Hanoi by 12%. Meanwhile, the proposed 24-hour LEZ for motorcycles in the area has the potential to reduce GHGs by 35%. These results show that reducing emissions from motorcycles brings climate and environmental co-benefits.