城市街道峡谷内机动车排放污染物的扩散规律

街道峡谷中机动车排放污染物的扩散取决于屋顶风向和风速,并受街道峡谷宽高比、峡谷两侧街区建筑物高度的对称性和高度分布及街区形状等因素的影响.街道峡谷宽高比接近1时,递升型峡谷以及宽阔街道有利于污染物的扩散;可以通过改变街道线源附近街区内建筑物的高度来明显降低污染物浓度.城市建筑规划中若科学考虑上述影响可以减少街道峡谷内污染物的积聚. 

Review of Dispersion Characteristics of Vehicle Emission Pollutants in Urban Street Canyons

The dispersion characteristics of vehicle emission pollutants in street canyons depend on roof level wind speed and direction,and are affected by street canyons width/height ratio and symmetry,and the shape and building heights distribution of blocks surrounding line sources.Pollution concentrations in street canyons with canyons width/height ratio around 1,with step\|up notch configuration or with wider street are relatively low.Street level concentrations can be significantly reduced by introducing variable geometry designed specially to increase dilution in the immediate vicinity of the line source.It is concluded that the consideration of the above factors in construction plan may bring pollution levels down.