Dust Retention Effect Of Urban Forest Vegetation

Urban forest plants are the natural filters of particulate matter in the air,which play a key role in improving the atmosphere environment quality.This paper takes the plants of four typical functional areas in Chang'an District of Xi 'an as examples: Qingliang Mountain Forest Park(recreational area),Jinduicheng Community(commercial residential area),Ziwu Avenue(traffic area)and Northwest University(cultural and educational area).The amount of dust retention of the area of unit leaf is measured by elution method.The magnetic susceptibility is measured by the magnetic susceptibility tester.The particle size of the leaf surface dust is determined by the particle size analyzer.And the comprehensive dust retention index is calculated by the comprehensive index method.The seasonal variation of these indexes is analyzed according to the same environment and different environments,and the main results are as follows:(1)Under the same environmental conditions,the plants with larger average dust retention per unit leaf area are Magnolia grandiflora,cedar,Pittosporum tobira,Photinia frase;the amount of dust retention per unit leaf area of the plant in different seasons is: spring> winter > Summer.(2)Among the four selected plots with different environments,the order of dust retention is: Ziwu Avenue > Northwest University > Jinduicheng Community > Qingliang Mountain Forest Park;(3)In the same environment,the magnetic susceptibility of iris and Prunus Cerasifera is stronger.In the same environment,winter and summer plants have higher magnetic susceptibility,while spring plants have the lowest magnetic susceptibility.In different environments,the magnetic susceptibility of the same plant is as follows: Ziwu Avenue > Jinduicheng Community > Qingliang Mountain Forest Park > Northwest University.(4)Plants mainly adsorb particles with small particle size in the air.In this study,the plants mainly retained PM1 and PM2.5,and the retention of these two kinds of particles was more than 80%.(5)Among the common urban forest plants in Chang'an District,Platycladus orientalis,Viburnum odoratissimum,Magnolia grandiflora and iris have strong comprehensive dust retention capacity,while the plants with poor comprehensive dust retention capacity are Ophiopogon,Sophora japonica and Koelreuteria paniculata.