城市道路行道树绿带对PM_(2.5)的滞尘效应及其变化分析

Analysis of Dust-retention Effect on PM_(2.5 ）in City Avenue Greenbelts

以城市道路行道树绿带植物群落为材料,对45个样方分别进行减尘率以及不同高度、宽度、时间条件下PM2.5浓度的测定,分析行道树绿带对PM2.5细颗粒物的滞尘效应及其时空变化。研究显示,不同结构植物群落对PM2.5滞尘效应的强弱顺序为:乔草型>乔木型>草坪型>乔灌型>乔灌草型>灌草型;植物种类丰富,具有乔木、草本植物或灌木球零散布局的植物群落配置模式对PM2.5的滞尘效应较强;群落垂直空间中PM2.5在10m高处浓度最高,5m处最低;而PM2.5浓度在群落水平空间的中心位置最高;群落中PM2.5随时间的大致变化在9:00浓度最低,之后曲折上升,在15:00达到最高,随后呈现缓慢下降趋势。

The research takes avenue greenbelt plant communities in city road as material, measures the reducing dust ratio and PM2.5 concentration in different height, width, time conditions for 45 quadrats, and analyses street tree greenbelts dust-retention effect of PM2.5 fine particles and the changes. The results showed that the dust-retention effect of different types of plant communities on PM2.5 is： arbor ＋ grass 〉 arbor type 〉 grass type 〉 arbor ＋ shrub 〉arbor 4- shrub ＋ grass 〉 shrub ＋ grass; the dust-retention effect of plant community with abundant plant species and trees, herbs or scattered shrubs is stronger; the PM2.5 concentrations in vertical space is highest in 10m, and lowest in 5m; in level space of the highest concentrations is the center of community; and PM2.5 in community along with the time change approximately in 9 o＇clock is the lowest, and then rises in twists and turns, reaching the highest in 15 o＇clock, and then subsequently shows a slow downward trend.