Analysis Of The Influence Of Road Vegetation On The Diffusion Of Inhalable Particles Based On Micro Climate Simulation

In recent years,the frequent occurrence of fog and haze,making residents increasingly conceemed about the city's ecological problems.How to improve the air quality in the streets has become an important topic of ecological city construction.The construction of road green space system plays an important role as an important measure to prevent road pollution.In this paper,using the method of micro climate simulation,simulation and analysis in the street canyon aspect ratio of 0.5,0.9,1.2,the spread of the PMl0 concentration in different wind speed and direction,temperature,humidity and other meteorological conditions,and compared the changes of different aspect ratio and different road greening form,different weather conditions on the influence of the concentration of inhalable particles,and then summed up the changes of pollutant concentration.On the other hand,this article from the case perspective,select the forest road,Baiziwan Road,Jiaodaokou East Street,North Street,Dongzhimen Agricultural Exhibition Hall Road 6 road road in Beijing city as a typical case,through different sampling points set,measured the two seasons of winter and summer meteorological factors and PM 10 concentrations,by comparison of simulation data and the measured data,the micro climate simulation of inhalable particles diffusion function evaluation of the model for the authenticity and reliability of the actual situation reflected in the diffusion of atmospheric particulate matter.The results are summarized as follows:(1)PM 10 concentration in winter was higher than that in summer.(2)PM 10 concentration trend is roughly the same,in addition to individual extreme weather roads,basically showing morning and evening high,low daytime trend.The general minimum value appears between 10:00-16:00,18:00 easy to appear the highest value.(3)In the case of high aspect ratio,the arrangement of shrubs had the most obvious effect on the decrease of PM 10 concentration,followed by the combination of tree and shrubs.The effect of shrubs on reducing PM 10 concentration was weak,and the effect of shrub on PM10 concentration The weakest.(4)When the vegetation setting is the same,the aspect ratio is smaller,that is,in the case of wide street,the more obvious the decrease of PM 10 concentration in the street,the more spacious the street,the more favorable the air and the outside air,So that the lower the concentration of PM 10 in the street;the higher the contrary.(5)The effect of the arrangement of the tree,the johny and the rhizome-grass on the air flow is greater than that of the shrub,and the effect of the shrub on the air flow from the ground to about 6 m,while the other three layouts can reach 12-15m.Indicating that the effect of tall trees on the wind is relatively large,low shrubs on the role of the wind smaller.