Research On Vehicle Emissions In Underground Garages Based On Vehicle Emission Model

Developemnt of underground garage could promote the use of underground space and alleviate the scarcity of land resources on the ground.Howeve,the environment in underground garage is relatively closed which means vehicle exhaust tends to accumulate and harm human health.Control pollutant source is an effective way to improve air quality,and it is necessary to predict vehicle exhaust emissions scientifically.Using vehicle emission model to predict emissions is an important field.This paper modifies and applies the road vehicle emission model to calculate vehicle exhaust emissions which include CO and particulate pollutants(PM10 and PM2.5)in underground garage,and then calculate ventilation rate and air changes.Firstly,make comparison of five vehicle emission models which have been used widely,and determine that MOVES2014 a is the calculation model of this paper.To apply the model to the case underground garage,the vehicle operation state should be simplified as cold boot and departure state,warm boot and departure state as well as departure state with low speed.Introduce the meaning of coefficients,principle and method for determining their values in each step,and then localize values of coefficients.In the aspects of temperature,humidity and air-conditioning utilization,pollutant emissions are adjusted,which can lay the foundation for analyzing the rationality of calculation results.According to the three simplified vehicle operation states,the calculation results are arranged,and in each operation state,the variation of total emissions and emissions of each substate are analyzed based on different pollutants respectively.Using air changes of 6 h-1 to calculate the actual concentration of pollutants,and judge the pollution level of underground garages in each season.A new method to determine the air changes is proposed.The CO calculation results of model are converted to forms of CO emissions per vehicle in unit time,and the converted values are compared with the values determined by traditional methods to determine the appropriate method under different conditions.The lane of the underground garage is divided to different parts by different utilization rate,and the pollutant emissions as well as pollutant emissions per unit lane length is calculated in different lane parts.The calculated data are analyzed from the temporal and spatial perspective respectively,and this paper offers suggestions which include air outlets arrangement and ventilation rate determination to lane district.According to vehicle operation state and pollutants,using dilution concentration method to calculate the required ventilation rate and air changes for underground garages which are under the condition of full-load operation and with a certain vehicle access frequency separately.Apply the new established method of determining air changes and set air changes as 4 h-1.To verify the rationality of 4 h-1,the outdoor air with desirable quality is used to dilute the particulate pollutants in underground garages.Finally,give advice on ventilation system of underground garages and air volume adjustment strategy.