Modelling the effectiveness of urban trees and grass on PM2.5 reduction via dispersion and deposition at a city scale
Modelling the effectiveness of urban trees and grass on PM2.5 reduction via dispersion and deposition at a city scale
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DOI：
10.1016/j.atmosenv.2016.09.033
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发表时间：
2016-12-01
影响因子：
5
通讯作者：
Leigh, R. J.
中科院分区：
文献类型：
--
作者：
Jeanjean, A. P. R.;Monks, P. S.;Leigh, R. J.
绿色基础设施可以通过树木的分散和建筑物、树木和草地的沉积相结合，减少城市规模的PM2.5交通排放。PM2.5浓度的模拟使用经过验证的CFD模型进行。一个2 x 2 km的区域已被重建为莱斯特（英国）市中心的三维表示，其规模大于大多数其他CFD研究。将树木空气动力学的影响与树木和草的沉积能力结合起来也是尚未以这种规模进行建模的事情。结果显示，在莱斯特市的夏季，树木对PM2.5浓度的空气动力学分散效应导致PM2.5浓度降低9.0%。相比之下，由于树木上的沉积（11.8吨年（-1））和草地上的沉积（2.5吨年（-1）），PM2.5也减少了2.8%和0.6%。树木和草被证明有更大的影响，局部，当考虑减少整个边界层时，发现PM2.5的减少较小。像莱斯特市中心这样建筑密集的地区植被相对较少，因此对PM2.5浓度的影响较小。结果发现，建筑物上的颗粒物沉积小于0.03%，可以忽略不计。根据树木和草地的地表面积分数及其沉降速度，推导出了描述PM2.5变化的经验方程。(C)2016作者出版社：Elsevier Ltd
Green infrastructure can reduce PM2.5 traffic emissions on a city scale, by a combination of dispersion by trees and deposition on buildings, trees and grass. Simulations of PM2.5 concentrations were performed using a validated CFD model. A 2 x 2 km area has been reconstructed as a 3D representation of Leicester (UK) city centre which is on a scale larger than most of the other CFD studies. Combining both the effects of tree aerodynamics and the deposition capabilities of trees and grass is also something that has not yet been modelled at this scale. During summer time in Leicester City, the results show that the aerodynamic dispersive effect of trees on PM2.5 concentrations result in a 9.0% reduction. In contrast, a decrease of PM2.5, by 2.8% owing to deposition on trees (11.8 t year(-1)) and 0.6% owing to deposition on grass (2.5 t year(-1)) was also observed. Trees and grass are shown to have greater effects locally, as smaller decreases in PM2.5 were found when considering reduction across the whole boundary layer. Densely built areas like Leicester City centre have relatively less vegetation and subsequently have a smaller effect on PM2.5 concentration. It was found that particle deposition on buildings was negligible with less than 0.03%. An empirical equation was derived to describe the changes in PM2.5 based on ground surface fraction of trees and grass, and their deposition velocities. (C) 2016 The Authors. Published by Elsevier Ltd.