福州市行道树对交通污染物扩散的影响

Influence of Urban Roadside Trees on Vehicular Pollutant Diffusion in Fuzhou

选择福州市中心城区3种典型的行道树结构作为研究对象,以CO为交通污染物的示踪气体,分别对绿化带两侧,即道路中央和人行道上CO浓度的时空变化进行了测定,分析了道路中央CO浓度与人行道上CO浓度的差值ΔC。研究结果表明:不同结构的行道树对交通污染物扩散有显著影响。主干道低覆盖度结构,最有利于交通污染物扩散;主干道高覆盖度结构和支路结构,则不利于交通污染物的扩散,使大量污染物涌入人行道,对行人健康构成危害。交通污染物的扩散效果取决于树冠结构,通过对各道路树冠结构的研究发现,疏透度与覆盖度均较小时,扩散效果最好;疏透度较大、覆盖度也较大时,扩散效果最差。

Three kinds of typical roadside trees were selected as samples in the center of Fuzhou.CO concentration was separately recorded in the street and the sidewalk covered with trees by using CO as a vehicular pollutant tracer.The variation of CO concentration between streets and sidewalks was analyzed at different height.The results showed that different structure of roadside trees had notable effect to vehicular pollutant diffusion.The most beneficial to vehicular pollutant diffusion was the road with lower ca...