Integrated Emission Mitigation Strategies Of Air Pollutants And CO₂ For On-road Vehicles In China

China has been embracing rapid socio-economic growth and urbanization over the past decades,which also has spurred an impressive amount of motorization indicated by skyrocketing vehicle ownership in China.The increase in vehicle usage has created substantially challenges to the environment,climate and energy systems.Therefore,integrated emission mitigation strategies targeting both air pollutants and CO₂ are essential to society.This study collected large samples of real-world vehicle emission data and vehicle usage profiles in China and developed a localized model to calculate the emissions of major air pollutants and CO₂.By establishing multi-year emission inventories,this study not only quantifies the historical trends in China's vehicle emissions but also forecasts the future trends under various emission control scenarios.Furthermore,this study estimates the emission reduction potentials of air pollutants and CO₂ using an optimization analysis method and proposes integrated mitigation strategies for the vehicle emissions of air pollutants and CO₂ in China.The results indicate that China's total vehicle emissions were estimated to be 4.16 Mt of HC,27.4 Mt of CO,7.72 Mt of NO_X,and 0.37 Mt of PM2.5 in 2013.The spatial heterogeneity of the social-economic development and population density in China has also resulted in a significantly higher emission density in the three developed regions of East China.These three developed regions only account for 4.4% of China's total territory area but are estimated to have been responsible for nearly 20% of the total vehicle emissions in 2013,more aggressive emission controls are required to lower emissions in the future.Future scenario analysis suggests that a no additional policy approach would not lead to the improvements in emissions that are required.Under the most aggressive scenario with tightened standards for vehicle emissions and fuel quality,restricted vehicle population,lowered vehicle-use intensity,and large scale penetration of alternative fuels and electric vehicles,the China total vehicle emissions of HC,CO,NO_X and PM2.5 in 2030 could be reduced by approximately 66%,75%,69% and 90%,respectively,relative to 2013.Emission of CO₂ would also peak around 2020 and decrease by 2% per year since then.Using an analysis of typical technologies of collaborative optimization,the results show that without a consideration of the air pollutant emission reduction,the light-duty vehicles could meet future stringent fuel economy goals through technical improvements of conventional gasoline cars.Nevertheless,if emission reductions of air pollutants become constraints as well in the future,fleet electrification including hybrid powertrain and battery electric vehicles will be required to achieve the coordinated emission reductions of air pollutants and CO₂.This study further establishes integrated emission mitigation strategies by province according to local characteristics based on social-economic development levels.Therefore,this study can provide significant support for better vehicle emission control of air pollutants and CO₂ emissions in China.