title: Assessment of vehicle emission programs in China during 1998-2013: Achievement, challenges and implications.
abstract: China has been embracing rapid motorization since the 1990s, and vehicles have become one of the major sources of air pollution problems. Since the late 1990s, thanks to the international experience, China has adopted comprehensive control measures to mitigate vehicle emissions. This study employs a local emission model (EMBEV) to assess China's first fifteen-year (1998-2013) efforts in controlling vehicles emissions. Our results show that China's total annual vehicle emissions in 2013 were 4.16 million tons (Mt) of HC, 27.4 Mt of CO, 7.72 Mt of NOX, and 0.37 Mt of PM2.5, respectively. Although vehicle emissions are substantially reduced relative to the without control scenarios, we still observe significantly higher emission density in East China than in developed countries with longer histories of vehicle emission control. This study further informs China's policy-makers of the prominent challenges to control vehicle emissions in the future. First, unlike other major air pollutants, total NOX emissions have rapidly increased due to a surge of diesel trucks and the postponed China IV standard nationwide. Simultaneous implementation of fuel quality improvements and vehicle-engine emission standards will be of great importance to alleviate NOX emissions for diesel fleets. Second, the enforcement of increasingly stringent standards should include strict oversight of type-approval conformity, in-use complacence and durability, which would help reduce gross emitters of PM2.5 that are considerable among in-use diesel fleets at the present. Third, this study reveals higher HC emissions than previous results and indicates evaporative emissions may have been underestimated. Considering that China's overall vehicle ownership is far from saturation, persistent efforts are required through economic tools, traffic management and emissions regulations to lower vehicle-use intensity and limit both exhaust and evaporative emissions. Furthermore, in light of the complex technology for emerging new energy vehicles, their real-world emissions need to be adequately evaluated before massive promotion.
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Xiaomeng
authors.initials: X
authors.lastname: Wu
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; State Environmental Protection Key Laboratory of Source and Control of Air Pollution Complex, Beijing 100084, China. Electronic address: ywu@tsinghua.edu.cn.
authors.forename: Ye
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA. Electronic address: zhshaoju@umich.edu.
authors.forename: Shaojun
authors.initials: S
authors.lastname: Zhang
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; State Environmental Protection Key Laboratory of Source and Control of Air Pollution Complex, Beijing 100084, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Liu
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; State Environmental Protection Key Laboratory of Source and Control of Air Pollution Complex, Beijing 100084, China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Fu
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; State Environmental Protection Key Laboratory of Source and Control of Air Pollution Complex, Beijing 100084, China.
authors.forename: Jiming
authors.initials: J
authors.lastname: Hao
mesh_terms: D000124:Achievement; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis* / Q000266:history / Q000517:prevention & control; D002681:China; D058735:Environmental Policy / Q000266:history; D005544:Forecasting; D049673:History, 20th Century; D049674:History, 21st Century; D008962:Models, Theoretical; D018986:Motor Vehicles; D001335:Vehicle Emissions / Q000032:analysis* / Q000517:prevention & control
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions
keywords: Air pollution; China; Control; Emissions; Vehicle