Variation Characteristics Of PM_2.5 Concentration In Greenland Plant Communities In Different Spatial On Campus Of Zhejiang A&F University

In order to explore the variation characteristics of PM_2.5 concentration and the factors affecting the concentration change in different spaces of green spaces on campus in Hangzhou,this paper selected the green areas of four different spaces in the East Lake Campus of Zhejiang A&F University in Lin'an District as the research object.From August 2017 to August 2018,the PM_2.5 concentration in the green space was monitored,and a microcomputer laser dust meter was placed in each of the four experimental plots for simultaneous monitoring.At the same time,the meteorological factors?wind speed,temperature and relative humidity?were recorded in real time using a hand-held anemometer.The data were analyzed with correlation analysis,linear fitting and multiple stepwise regression,etc.The relationship between PM_2.5 concentration changes and meteorological factors in green areas of each different space was studied.The time,monthly and seasonal variations and spatial variation characteristics of PM_2.5 concentrations in green areas of various spaces and the effects of plant communities on airborne particulate matter were probed into.The main findings are as follows:?1?The concentration of PM_2.5 is most directly affected by meteorological factors.The relative humidity plays the most important role,followed by temperature,and the wind speed is less influential.There is a significant positive correlation between PM_2.5 concentration and relative humidity,and a significant negative correlation between that and temperature.?2?In terms of time variation,the time variation trend of PM_2.5 concentration in green areas of the four experimental plots showed high consistency.The figure of PM_2.5 concentration in the clear weather showed an"L"form change during the day.The overall trend is high in the morning,low in the afternoon,and rising in the evening.In the field of monthly variation,the PM_2.5 concentration is the lowest in August and highest in January,and as for the seasonal variation,the ranking of the concentration follows the order:winter>autumn>spring>summer.?3?The ranking of the spatial variation characteristics of PM_2.5 concentration in four experimental plots from low to high are:spring:plot2<plot3<plot4<plot1,summer:plot3<plot1<plot4<plot2,autumn:plot2<plot4<plot3<plot1,winter:plot3<plot1<plot2<plot4.The dust-retention effect of plant communities in spring and summer is significant.