Research On The Effect Of Urban Forest On PM_2.5 Based On Remote Sensing Images

Under the macroenvironment of the rapid development of industrialization, the fog and haze is not only a small problem in a city, but also a big problem in many regions. PM_2.5 （Fine Particulate Matter） is the culprit for the pollution of atmospheric environment of the city. And it can cause different degree of harm to multiple systems of human physical health. It has been primary pollutant of Particulate Matter （PM10） in Harbin City. Urban Forest can reduce the mass concentrations of PM_2.5 by adsorption. Therefore, rational planning the layout of the urban forest can not only mprove air quality and then adjust the urban ecological environment effectively but also has a great benefit to people’s physical and mental health.This paper collected and arranged the mass concentrations of PM_2.5 data, PM10 data, main air polutants （including SO2、NO2 and CO） and meteorological data （including atmospheric pressure、wind speed、temperature and relative humidity） in ground minitoring station in 2014 full year in Harbin City. It analyzed respectively the changing characteristics of the mass concentrations of PM_2.5 and PM10 at different time scales （day, month and season）. And it analyzed the relevance between them by the SPSS software. It analyzed the relevance between the mass concentrations of PM_2.5 and the concentrations of main air pollutants in different relative humidity distinguishing between precipitation days and non precipitation ones. It also made the relevance analysis between the mass concentrations of PM_2.5 and meteorological factors.This study made use of MOD04 Level2 Aerosol Optical Depth （AOD） data of modis sensor in Terra satellite. It established the remote retrieval model of AOD data and the mass concentration of PM_2.5. It compared and analyzed the five fuction modles. Selected the best one from them and calculated the accuracy of the modles. It estimated seasonal spatial distribution characteristics of the mass concentrations of PM_2.5 respectively under the support of ENVI software in the part of Harbin City. And it analysed the reasons of this kind of causing the distribution characteristics from four angles.The difference of PM_2.5’S mass concentrations between winter and summer expressed the urban forest’s reduction effect. And it added the proportion of the urban construction land area to revise. It used Landsat remote sensing image to extract landscape covering type map. And it used FRAGSTAS software to calculate the landscape pattern index. It analyzed the relevance between the index features of landscape patten and PM_2.5 reduction relationship. It proposed the viewpoint that we should make use of urban forest’s reduction effect to PM_2.5 and planned the layout of urban forest rationally and reduced the pollution of PM_2.5 under the premise of not affecting the economic development. To banlance the contradition between industrial development and environmental protection, we should protecte the ecological environment and human health, and ultimately achieve the goal of coordinated sustainable development of human and nature.