Research On Pollution Characteristic Of Vehicle Exhausts In Ningbo And Its Prevention Measurement

With the rapid increment of vehicles,exhausted gases from them have being more and more concerned.Hazardous air emission from vehicles has become major issue in the protection of atmospheric environment in Ningbo, as one of the developed cities situated in southeast coast of China.Exhaust pollutant emissions from on-road vehicles in Ningbo were analyzed and predicted from now to in next fifteen years by using the Mobile5 and Part5 models of EPA in this paper,the VOC Source Profile and Benzene Compounds Emission of Various Vehicles were also studied.Major results were listed as follows:1.The methods of sampling on-road vehicles and analyzing of VOCs in vehicle exhausts were developed.2.The influences on the emission of VOCs and benzene compounds from vehicles with different emission control technology,type of vehicle,driving velocity and travel mileage were discussed.The first one of the results was that there were 47 sorts of VOCs in vehicle exhausts,the second was that the emission quantities of VOCs from petrol vehicles were more than diesel ones, the third was that unelectronic injection vehicle,petrol bus and taxi were high emission sources of VOCs and benzene compounds,the fourth was that the emission of VOCs and benzene compounds were much higher at the normal driving speed than at cold and idle start,the fifth was that the emissions quantities of VOCs and were relatively low at speed of 40-60kw/h,the final was that the emission concentration of VOCs and benzene compounds would increase greatly when catalysts became invalid.3.The calculation results showed that the total emission quantities of THC, CO,NOx and PM₁₀was 49000,26800 and 23000 and from motor vehicles in Ningbo in 2006 respectively by using the Mobile5 and Part5 models of EPA and estimated method of fuel consummation.Among these vehicles, motorcycles,heavy petrol cars and heavy diesel cars individually accounted for 40%,27%,and 35%in the total emission quantities of THC,CO and NOx. Emissions of PM₁₀is 1300 tons and PM₁₀emissions from heavy diesel motorcars are the highest proportion,accounting for 38%.4.On the basis of actual measurement the total emission quantities of benzene compounds from the vehicles were 229.79 tons in 2006,of which the emission quantity of toluene was up to 93.86 tons,and that of benzene was 41.77 tons and xylene was 47.57 tons.The result explained that vehicle exhausts was a major source of benzene compounds in the urban atmosphere in Ningbo.5.The emission quantities of THC,CO and NO_x would be forecast in Ningbo in 2020 with the method of elastic coefficient under uncontrolling,lowly controlling and highly controlling measuments.6.Measurements and suggestions for controlling exhaust pollutant emissions from vehicles,such as the enforcement of an inspection/maintenance(I/M)program would be put forward according to study results.