A Study on the Effects of Greening Patterns on the Diffusion of PM10 Traffic Pollution on Urban Streets
In order to clarify the impact of urban street greening on the diffusion of pollutants PM10 emitted by motor vehicles, and to provide scientific basis for street planting design, this study conducted investigation on the influence of wind direction and greening Model of the PM10 concentration in the sidewalk.The urban micro-climate software ENVI-met was adopted in this study to simulate the dispersion rule of vehicle emission of PM10 under the conditions of three kinds of wind directions: vertical, 45° towards the street (oblique wind) and parallel to the street (parallel wind) on pedestrian activity intensive branch in the downtown area of Wuhan.The results have indicated that the PM10 is stacked on the sidewalk on the leeward side by the vertical wind and the oblique wind.In addition, the emission of PM10 reaches the highest when it is the vertical wind and the lightest when it is the parallel wind.Over ally, except for Model 7 under oblique wind conditions and Models 3, 7 and 8 under parallel wind conditions,PM10 on the sidewalk does not increase significantly, the other greening Models all aggravate PM10 pollution on the sidewalk.The green belt has better performance on reducing the pollution under the vertical wind and oblique wind conditions, with trees on the windward side (Model 7) than on the central (Model 6) and leeward side (Model 8).With the Models with two green belts, the performance of Model 2 (trees only) is better than Model 3 (trees and shrubs).When the wind is parallel to the street, the air quality is better in Model 7, Model 8 and Model 3 than in Model 2 and Model 6.The PM10 concentrations of both sides are the same when the green belts are arranged symmetrically.However, if they are arranged on the same side, the PM10 concentration of the green belts side is slightly higher than that of the contralateral side.In addition, the pollution of the models with three green belts are the most serious under all wind directions.Model 5 of planting three rows of trees is better than the Model 4 (trees on both sides, small trees and shrubs in the central area).The results have indicated that: ①The average concentrations of PM10 on both sides of the pavements of the street were increased after planting the green belt, that is, the pollution increased.In addition, the emission of PM10 reaches the highest when it is the vertical wind and the lightest when it is the parallel wind.②PM10 is accumulated on the leeward side by vertical wind and oblique wind, and the more green belts, the pollution is more serious.③There are obvious advantages and disadvantages among the patterns with the same number of green belts under oblique wind: the single row of trees has better performance on reducing the pollution, with trees on the windward side is the best, with trees on the center is next, and with trees on the leeward side is the worst;In the two green belts patterns, the planting of trees on both sides is better than that of planting trees and hedgerows in the two green belt patterns, and in the three green belt patterns, the planting of trees in the central subzone is better than that in the planting of small trees and hedges.④Parallel wind conditions, with three green belt pollution model is relatively heavy, planting trees on both sides of the single row second, the windward side of single row of trees, the leeward side of single row of trees, planting trees and hedges on both sides of a double layer structure, the single row of trees less pollution.⑤Only under the condition of parallel wind, the hedges on both sides of the trees can prevent PM10 from spreading to the footpaths.
urban street greening pattern diffusion of inhalable particles ENVI-met numerical simulation
Ren Sijia Wu Changguang
Department of Landscape Architecture, College of Horticulture and Forest Sciences,Huazhong Agricultu Department of Landscape Architecture, College of Horticulture and Forest Sciences,Huazhong Agricultu
国际会议
上海
英文
522-541
2018-01-27（万方平台首次上网日期，不代表论文的发表时间）