Assessing the impact of modal shift and electric vehicles (EV) adoption on air pollution: A case study

Global increase in motorization and rapid urbanization has made this sector, a significant contributor to the air pollution and developing countries like India follow the same trend with a higher intensity. The present study attempts a detailed assessment of vehicular emission trends in India with studies conducted in Bhubaneswar, a Tier - II smart city. The study involves questionnaire survey, videography techniques along with a bottom-up activity-based framework incorporating empirical fleet age distributions and Bharat Stage (BS) standards to encompass local field traffic conditions. Questionnaire survey was conducted to examine vehicle age and emission-standards of vehicles. Using IPCC guidelines and the field based framework, the emission parameters - Average Fuel Usage, Fuel Consumption, and Total Pollutant Emission were estimated, by considering traffic volume, mileage, and emission standards. Results showcased that real-world emissions are characterized by vehicle type, occupancy, and fuel efficiency. Two-wheelers despite exhibiting lower per-capita emission, contribute to the second highest emission among private vehicles (11.98 g of CO and 7.18 g of HC+NO x ). 4Ws exhibit the highest Per-Passenger Emission Intensity (g/person-km), due to low occupancy and higher space. Heavy vehicles (buses) emit lowest Per-Passenger Emission Intensity (g/person-km) (0.11 g CO and 0.05 g HC+NO x ). Multi-model time-series forecasting indicates that the EV traffic share in Bhubaneswar is projected to rise from 7% to a range of 10.5% - 13.8% over the next five years. For every 1% increase in the EV fleet share, an average of 43.4 g of combined criteria pollutants is saved per kilometer traveled across city corridors. While a complete modal shift to high-occupancy buses provides the highest per-passenger efficiency (>99% reduction), even a shift of 10%-25% from private vehicles to buses will lead to pollutant savings of 7.4–18.5%. The study reflects the requirement of strategic planning for EV adoption and shifts to public transportation for sustainable future.