Prediction Of Roadside Carbon Monoxide Concentration Based On Vehicle Driving Conditions

Studying the generation and dispersion of pollutants caused by motor vehicles in urban traffic system and forecasting the roadside pollutant concentrations are important to reduce energy consumption and urban pollution,and to improve the ecological environment of urban residents.However,the effect of traffic produced turbulence on the roadside pollutant concentrations has not been systematically analyzed in existing prediction models.Therefore,roadside pollutant concentrations for different vehicle driving conditions are analyzed in this study,with carbon monoxide chosen as the pollution representative,and computational fluid dynamics simulation chosen as the main approach.This study includes three main contents.First,typical vehicle model was selected and numerical simulation model was created for single vehicle.The results were verified through wind tunnel experiment.Secondly,the numerical simulation model for two cars under car-following condition was established based on the model for the single vehicle.The pollutant concentrations beside the vehicles were explored under different vehicle specific powers.Thirdly,the revised model of roadside pollutant concentrations was created based on traffic produced turbulence.The numerical simulation model for typical street canyon was established,and verified through field measurement.The results indicate that wind velocities in low values have no significant effect on the pollutant concentration distribution in the asymmetric street canyon.The planting of the roadside trees will enhance the asymmetric characteristics of the flow field in the canyon,and hinder the distribution of pollutants.In the presence of the main building and the annex structure on the side of the street canyon,the flow directions have significant effects on the pollutant concentration distribution in the street canyon.The pollutants are easy to accumulate in the windward side while the annex is located in the windward direction.The pollutants are easy to accumulate upside the annex roof while the annex is located in the leeward direction.Therefore,the main building and annex structure should not be located in the windward direction,in order to improve the healthy life quality of urban citizens.