Simulation Study and Evaluation the Impact of Road Greenbelt Layout on Particulate Matter Dispersion and Removal

Abstract: As the skeleton of the city, the road is the most significant one among the five elements of the city image. The road greenspace have been suggested as one of the green infrastructures that could improve near-road air quality. The road greenbelt of the cross section layout is the core content of road green space planning and design. However, existing studies have primarily focused on the effect of different plants on atmospheric particulate matter (PM), whereas the impact of road greenbelt layout on particulate matter dispersion and removal has not been adequately addressed. This paper takes traffic-induced PM2.5 as the research object, the typical daily meteorological parameters of Wuhan city were selected, through the 3D computational fluid dynamics (CFD) model ENVI–met, and selecting 1.5 m high concentration of PM2.5 as indicator factors of microclimate to simulate the influence of different road greenbelts rate and road Green Belt layout on the microclimate of road space. The results show that: 1) the green type of road cross section has significant influence on the distribution of particulate matter. The road greening results in the increase of particulate concentration of motor vehicles and the decrease of the concentration of non-motorized driveway and pavement. 2) In the same form of road section design, increasing green volume can reduce PM2.5 concentration of pavement. 3) The two-board and three-belt type with a 40% greening rate had the best effect on sidewalk reduction, and the growth rate was increased by 27% compared with the non-greening road.