Assessment of transport emissions in Megacities the case of Delhi after CNG introduction 1,2Ragini Kumari, 2Luc Int Panis, 2Rudi Torfs 1SES, JNU,New Delhi, India: School of Environmental Sciences, Jawaharlal Nehru University 2VITO NV (Flemish Institute for Technological Research), Belgium, Contact: raginivito@gmail.comtel. +91 9911859414 INTRODUCTION In Delhi, the capital of India, 70% of air pollution is due to vehicles (MOEF,1997). The fleet composition in Delhi is far different from any European or US city. Around 65% of the total fleet are motor-bikes (Two-wheelers). Only in 1990-91 emission standards came into force. The India-2000 (equal to the Euro I) standard was introduced in the year 1999/2000 and EuroII in 2000/2001. Simultaneously the quality of fuel was improved (Gasoline (reduced Pb content: 0.56 g/l (1996) to 0.013g/l (2000); reduced benzene content 5% (1996) to 1% (2000), Diesel (reduced S-content: 1.0% (1996) to 0.05% (2000). Before 2000/2001 vehicles were running only on gasoline and diesel. In 2001 CNG fuel was introduced in an effort to reduce the emissions especially from commercial vehicles. Public transport vehicles like buses, three-wheelers, taxies & light commercial vehicles were specifically targeted. Old vehicles were scrapped under order given by Ho’ble Supreme court in 1998. METHODOLOGY Annual Vehicular composition data was obtained from (ESD-2004-2005). Annual vehicular mileage data was obtained from two sources- CPCB., 2001b & Xie et al., 1996. Literature survey had been done to compare MEET-emission factor to that of emission factor used in past for the quantification of above pollutants.Average traffic flow was taken into account while working with MEET-function in context of Delhi. The speed of Two-wheelers, Three-wheelers, Four-wheelers (Taxies & Cars) estimated at 30km/h. Average speed for City Buses & HCV was 10km/h & for LCV 22km/h. Also Monte Carlo Sensitivity Analysis was done to know the relative importance of factors responsible for vehicular emission load. Segregation of vehicular fleet on the basis of type of fuel and engine type Use of annual vehicular mileage data for the calculation of total fuel used. Assessment of MEET function in Indian context. Compilation of emission factors for CNG driven vehicles & Use of VITO-emission functions Comparison of annual pollutant emission after CNG introduction Monte Carlo Uncertainty evaluation for – identification of critical parameters and test the robustness of our conclusions 2. STEPS FOLLOWED SITE OF STUDY : NCR DELHI, INDIA RESULTS & DISCUSSION 1. # REGISTERED VEHICLES IN NCR-DELHI (INDIA) 2. MONTE CARLO SENSITIVITY 3. FRACTIONAL PROPORTION OF FUEL CONSUMPTION 4. EMISSION REDUCTION AFTER CNG INTRODUCTION CONCLUSION The present work done fairly agrees with the MEET-functions only after wisely taking into account the type, size & age of the engine along with type of fuel used. Use of VITO emission-factors (EF) fairly agrees with the EFs available from local literature sources. Data such as n° of vehicles, annual vehicular mileage, fuel consumption etc are highly uncertain and need to be updated. Measurement of EF in Indian context is necessary for more accurate inventory of pollutants by CNG vehicles. More reliable statistical information should be collected on: fuel consumption of 2 stroke motorcycles, annual mileages driven & the fleet sizes of specific vehicle types for the better estimate. Our results show a decline in pollutant emissions after the introduction of CNG but there are other crucial factors (congestion, strict implication of vehicular norms, …) which should be taken into account, only then one can expect improved air quality in megacities like Delhi in India.