Peculiarities of volatile hydrocarbon emissions from several types of vehicles in Japan

Vehicle exhaust has been a very important hydrocarbon source in a big city. In Japan, five types of vehicles, light-duty gasoline (LDG), super-light-duty gasoline (SLD), liquid petroleum gas-fueled (LPG), light-duty diesel (LDD) and heavy-duty diesel (HDD) cars have been used widely for a long time. These vehicles have different fuels and exhaust gas treatment systems, which have not changed so largely since the late 1980s. The hydrocarbons [total hydrocarbon (THC), methane and 16 speciated volatile hydrocarbon components] emitted from 12 cars (one LDG, two SLD, two LPG, three LDD and four HDD) were investigated. As a result, the remarkable peculiarities of hydrocarbon emissions from the five types of vehicles were observed. Especially, the emissions from SLD and LPG cars have the peculiarities of high concentrations of total hydrocarbon (THC) and C₂ (ethylene and acetylene), C₃ (propane or propylene) or C₄ (i-, n-butanes) hydrocarbons in 16 components, which may be proposed to give a significant effect on 16 component hydrocarbons of the ambient air in big cities of Japan in addition to those from LDG and diesel (LDD and HDD) cars.