Influence of Moving Vehicles on Pollutant Dispersion in Street Canyon: A Numerical Study
The occurrence of “crazy bad air pollution in many cities of China often hits the international headlines.In Hong Kong,the outdoor air quality faces great challenges as well.According to the report released from the Environmental Protection Department of the Hong Kong Government,vehicular emissions and street canyon effects are the two main contributing factors to roadside air pollution.This paper outlines the findings from our numerical investigation of the dynamic pollutant dispersion as induced by moving vehicles within the street canyon environment of Hong Kong.The integrative computational fluid dynamics(CFD)models,including the standard k-ε model for airflow turbulence,the species transport model for gaseous pollutants,and the dynamic mesh model for moving vehicles,were validated by wind tunnel measurements as well as reported data from published literatures.Our findings confirm that moving vehicles could generate secondary airflow,and hence introduces additional ventilation effects.This leads to continuous interaction between the wind flow and the wake of vehicles,and in addition,promotes the mixing and transportation of the vehicle exhausted pollutants.Dynamic impacts of the moving vehicles on the airflow field(such as the flow velocity)and the pollutant dispersion(such as the concentrations of CO from a stationary line source and NO2 from the moving point source)were found highly dependent on:(i)The geometrical configuration of the street canyon;(ii)The mode of vehicular movements,such as in single-or multi-lanes and their travelling directions,and(iii)The position of the monitoring site,i.e.near the leeward/windward wall,at the middle of the street canyon,or near the two street end openings.
micro-climate sustainable neighbourhood roadside air quality
ZHANG Wenjing CHOW Tin-tai
Division of Building Science and Technology,City University of Hong Kong,Hong Kong SAR
国际会议
2017世界可持续建筑环境大会(the World Sustainable Built Environment Conference)
香港
英文
1075-1080
2017-06-05（万方平台首次上网日期，不代表论文的发表时间）