Abstract:

Road traffic is considered as one of the most important sources of air pollution with adverse effects on human health. Greenbelts of nonmotorized roads are not only used for beautification of a city but also contribute significantly to purify total suspended particulates (TSP) in atmosphere which are derived from motor vehicles. The aim of this study is to explore which greenbelt configuration mode is more efficient to purify TSP for different grade roads and to find out which meteorological factor has more significantly effect on the purification efficiency of TSP. Some stylegreenbelts were selected as research objects in this study. Through monitoring the concentration of TSP by the way of assigning sample points along the greenbelts, we studied the quantitative purification efficiency of greenbelts which has different structures and at different grade road to TSP. Meanwhile, the correlation analysis was performed between the purification efficiency of TSP and the vegetations status of greenbelt which measured by canopy density and shelterbelt porosity. Further, we explored the correlation between the purification efficiency of TSP and the temperature, relative humidity and wind speed using the grey correlation method. The results were as follows. The configuration structure which planted with arbor and the shrub will be best for the greenbelt of the arterial road to purify TSP, and the configuration structure which configured with arbor, shrub and herbaceous plant will be most suitable for the greenbelt of the minorarterial road to purify TSP. It showed that dungarunga and large shrubs should be give priority to when we design the nonmotorized road greenbelts at serious traffic road. The purification efficiency of the greenbelt to the TSP is higher when the canopy density value and the shelterbelt porosity value of the greenbelt was between 75%-90% and 10%-20%, respectively. The canopy density will reduced and shelterbelt porosity will rise for the vegetations disrobed of their leaves in autumn and winter, but the TSP concentration of most cities is highest at winter, so more green plants should be chosen to design greenbelts. In addition, the purification efficiency will rise if choosing more plants which has better ability to absorb dust. Relative humidity played an even more important role than temperature and wind speed to the purification efficiency of TSP