10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Real World Emission Factors of Fine Aerosol and Carbonaceous Constituents from On-Road Transport in India
JAI PRAKASH, Dilip Ganguly, Gazala Habib, Indian Institute of Technology Delhi
Abstract Number: 1465 Working Group: Combustion
Abstract Accurately measuring emission factors (EFs) are prerequisite for the correct emission estimates. The radiative forcing of carbonaceous constituents of aerosol (Elemental and Organic Carbon) are agreed to have significant climate implications over South Asia including India and China, where the abundance is high. However, a large discrepancy between model simulated and satellite retrieved absorbing aerosol optical depth was estimated in recent work by Bond et al (2013). The lack of knowledge on regional source activity, technological advances and unavailability of emission profiles of regionally important sources are stated as main reasons for such incongruity. For Indian on-road transport sector the emission estimates relied on EFs of PM2.5 measured either using chassis dynamometer following standard driving cycle or derived from emission models, and fraction of EC and OC adopted from literature for other countries. These EFs introduced an undefined uncertainty in recent emission inventories of road transport sector. None of the study has reported EC and OC emission factors for Indian vehicles. Therefore, for the first time, a technology based emission factors of OC and EC measured during on-road operation of vehicles in Delhi were used for refining the emissions estimates for the base year 2013. A logistic model was used with fixed parameters and vehicle registration data for the year 2013 to estimate the on-road vehicle population. The on-road vehicles were dominated by 2Ws, followed by 4Ws, others, LMVs-goods, HDVs-truck and buses with new vehicles comprising the majority of the on-road fleet. A portion of superemitter, which is highly unreliable, was assumed as 17% of the on-road population. Vehicle mileage and annual distance traveled were compiled from the literature and thus, fuel consumption was estimated at national level and disaggregated state to district level using vehicle population as proxy. Emissions of PM2.5, EC and OC were estimated as 260 (134-386) Gg y-1, 123 (65-181) Ggy-1 and 84 (37-130) Ggy-1 respectively. The PM2.5, EC, and OC emissions from the on-road transport sector for the base year 2013 contributed 7%, 17%, and 6% of total emissions from India. Another important finding of this work is new vehicles emit 70-80% of national level PM2.5 and EC compared to old vehicles, while old and new vehicle both equally contributed to OC emissions. The new emission factors from on-road measurement and emission estimates for on-road transport sector and its implications in climate forcing will be discussed.