Study On Bus Emission Pollution And Pollution Control Measures In Xi'an

With the number of motor vehicle increased at a very high speed, the contribution rate of Xi'an motor vehicle emission on air pollution rises rapidly, and most of these pollutants come from the city bus. Buses which running in the city where the population and vehicles concentrated. Its particular operating conditions made it become a major source of vehicle exhausted emissions. Exhaust emissions from buses has not only tarnished the image of the city, but also polluted the environment of cities. The health of residents and the ecological environment are confronted with a great threat. To solve the problem of hazardous air emission from buses has become the most important job of motor vehicle pollution control.In this paper, through the collection of information and actual research, the road construction, public transport structure and the features of bus transportation in Xi'an were analyzed. The research showed that Xi'an public transport had a wide gap to meet the urban development demand at present: overall layout of the road network was unreasonable, public transport network was distributed uneven, the density of the whole line was low, public transport infrastructure was relatively backward, the settings such as site number, station distance and line length need to be further optimized. There were great differences between urban and suburban bus operations.With the method of sampling and statistical analysis, emissions level of different types of buses was compared in this paper. Comparative analysis was made on vehicles burning fuel, age of the vehicle, engine technology and vehicle mileage to evaluate the differences in their emissions. Some conclusions were obtained as follows. Gasoline bus exceeded in a stable condition, however, the effect was not obvious after a period of rectification measures in technology, economy and management. CNG bus which emitted low emissions is a clean energy worthy of promoting. Diesel bus exceeded seriously, but Carbon emissions situation had obviously improved after a period of rectification. The more advanced engine technology the bus use, the lower emissions it exhausted. EFI bus emitted less than the carburetor bus. Soot emissions from turbocharged diesel vehicles were less than those from non-turbocharged diesel vehicles. With the age and vehicle-miles of travel increasing, the emissions from bus have a corresponding increase, this phenomenon is called deterioration. The relationship among age of the vehicle, vehicle mileage and exceeding rate was analyzed respectively. The results showed that emissions from gasoline and diesel buses had a significant deterioration trend, while the emission degradation trend of CNG bus was less obvious.The major factors affecting bus emissions in Xi'an were summarized, such as public transport structure, bus operating characteristics, level of vehicle technology, driving habits of Drivers, I/M system implementation, fuel structure, fuel quality and so on. Some reasonable and effective control measures and countermeasures were proposed from these areas, such as improve the structure and quality of fuel, strictly enforce in the I/M system, strengthen internal control of the public transport enterprises on vehicle emission pollution, speed up the system construction of bus pollution control and so on.