Evolution of on-road vehicle exhaust emissions in Delhi

For a 40-year horizon (1990-2030), on-road vehicle exhaust emissions were evaluated, retrospectively and prospectively, for the largest urban agglomeration in India - the Greater Delhi region with a combined population of 22 million in 2011 (Delhi along with Ghaziabad, Noida, Greater Noida, Faridabad and Gurgaon). Emissions of particulate matter, sulfur dioxide, carbon monoxide and volatile organic compounds (VOCs) reached their peak during late 1990s through early 2000s after which they reduced significantly through year 2012. On the other hand, nitrogen oxides (NOx) and carbon dioxide show an increasing trend. The most reduction in emissions between 1998 and 2012 occurred as a result of implementation of four sets of vehicular emission standards, removal of lead, reduction of sulfur content, mandatory retirement of older commercial vehicles, and conversion of diesel and petrol run public transport vehicles to compressed natural gas. In addition, changes in the vehicular technology have also contributed to controlling emissions especially in case of auto-rickshaws and motorized two-wheelers, which changed from two-stroke to four-stroke. The rising trend of NOx along with the presence of VOCs indicates increasing tendency to form ground-level ozone and as a result, smog in the region. We predict that the current regime of vehicle technology, fuel standards, and high growth rate of private vehicles, is likely to nullify all the past emission reductions by the end of 2020s. (C) 2015 Elsevier Ltd. All rights reserved

Role of urban growth, technology, and judicial interventions on vehicle exhaust emissions in Delhi for 1991-2014 and 2014-2030 periods

Between late 1980s and 2014, the Greater Delhi region has witnessed an increase in vehicular fleet, four sets of emission standards, and changes in engine technology and fuel usage. This paper presents and evaluate these measures on on-road vehicle exhaust emissions under four counterfactual scenarios - (a) no penetration of 4-stroke (45) 2-wheelers (2Ws) (b) no introduction of compressed natural gas (CNG) (c) no implementation of emission standards post 2000 and (d) no dual emission standards (supply of better fuel in the metropolitan areas and a grade lower for the rest). Introduction of 45 engines reduced VOC emissions by 90%, thus being the most effective compared to the three emission standards (BS-II, Ill, and IV) combined. Introducing CNG reduced 50% of PIV12.5 and increased 20% of NO emissions in 2014, mostly from buses and light duty vehicles. Implementation of emission standards affected all pollutants, with 60% reduction in VOCs and 20-30% reduction for the rest. Dual emission standards increased the PIV12.5, emissions from heavy duty vehicles, as much as the reductions from passenger vehicles, thus negating the benefits of the latter. Under the proposed road map of emission standards and vehicular technology by the Auto Fuel Policy 2025 committee, PM2.5 emissions in 2030 will be halved, CO emissions will reach three times, and VOC and NO emissions will at least stabilize compared to 2014 estimates. If leapfrogged to BS-VI in 2017, there will be additional reduction in NO, and VOC emissions. (C) 2015 Elsevier B.V. All rights reserved

Assessment of motor vehicle use characteristics in three Indian cities

Estimates of emissions and energy consumption by vehicular fleet in India are not backed by reliable values of parameters, leading to large uncertainties. We report new methods, including primary surveys and secondary data sources, to estimate in-use fleet size, annual mileage (kilometers per year), and fuel efficiency of cars and motorised two-wheelers (MTW) for Delhi, and except fleet size and annual mileage of cars, for Visakhapatnam and Rajkot. We estimated that the official number of registered cars and MTW in Indian cities is more than two times the actual number of in-use vehicles. The private vehicular fleet in India is the youngest, its fuel efficiency one of the highest, and annual kilometers travelled is the lowest, compared to many high-income countries, such as the USA and those in European Union. Along with high renewal rate of fleet, the data suggest that it is possible for India to have one of the most fuel-efficient vehicle fleets in the world in the future, if fuel-efficiency standards and fiscal policies to contain growing dieselization are implemented in the country at the earliest. (C) 2015 Elsevier Ltd. All rights reserved