title: Gaseous emissions from compressed natural gas buses in urban road and highway tests in China.
abstract: The natural gas vehicle market is rapidly developing throughout the world, and the majority of such vehicles operate on compressed natural gas (CNG). However, most studies on the emission characteristics of CNG vehicles rely on laboratory chassis dynamometer measurements, which do not accurately represent actual road driving conditions. To further investigate the emission characteristics of CNG vehicles, two CNG city buses and two CNG coaches were tested on public urban roads and highway sections. Our results show that when speeds of 0-10km/hr were increased to 10-20km/hr, the CO2, CO, nitrogen oxide (NOx), and total hydrocarbon (THC) emission factors decreased by (71.6±4.3)%, (65.6±9.5)%, (64.9±9.2)% and (67.8±0.3)%, respectively. In this study, The Beijing city buses with stricter emission standards (Euro IV) did not have lower emission factors than the Chongqing coaches with Euro II emission standards. Both the higher emission factors at 0-10km/hr speeds and the higher percentage of driving in the low-speed regime during the entire road cycle may have contributed to the higher CO2and CO emission factors of these city buses. Additionally, compared with the emission factors produced in the urban road tests, the CO emission factors of the CNG buses in highway tests decreased the most (by 83.2%), followed by the THC emission factors, which decreased by 67.1%.
authors.affiliation: College of Water Sciences, Beijing Normal University, Beijing 100875, China; State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Yue
authors.affiliation: College of Water Sciences, Beijing Normal University, Beijing 100875, China; Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address: chaifh@craes.org.cn.
authors.forename: Fahe
authors.initials: F
authors.lastname: Chai
authors.affiliation: State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Jingnan
authors.initials: J
authors.lastname: Hu
authors.affiliation: State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Jia
authors.affiliation: State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Bao
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Li
authors.affiliation: State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Liqang
authors.initials: L
authors.lastname: He
authors.affiliation: State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zu
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002681:China; D002947:Cities; D004784:Environmental Monitoring; D006838:Hydrocarbons / Q000032:analysis; D059206:Natural Gas; D009589:Nitrogen Oxides / Q000032:analysis; D001335:Vehicle Emissions / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D006838:Hydrocarbons; D059206:Natural Gas; D009589:Nitrogen Oxides; D001335:Vehicle Emissions
keywords: Compressed natural gas vehicles; Emission factors; Highway; Road tests