Study On The Characteristics Of Atmospheric Particulate Concentration In Typical Forest Communities Of Lin’an

As the smaller size particles,PM2.5 is difficult on its own gravitationa sedimentation,which represents a serious threat to human health as well as enviromnent quality,while vegetation has positive effect on regulating and retaining atmospheric particulates such as PM2.5.Therefore,this study is on two dimensions of forest community and individual,by reviewing the literature,field experimental sample survey,field data collection and recording,indoor chamber simulation experiments and many other steps,measured in Zhejiang Province,typical forest communities and plants on PM2.5,PM10 reduction and retention.The study attempts to compare the extent of PM2.5 and PM10,and to provide a reference for the city to reduce particulate pollution from the perspective of plant measures.The main conclusions are as follows:(1)Forest community scale: In this study,six different forest communities(the evergreen broad-leaf forest,Coniferous and broad-leaved mixed forest,Deciduous broad-leaved forest,Chinese fir forest,Bamboo forest,Pinus massoniana forest)were used as the research object.During the spring,summer and autumn(8:00-18:00)in 2014,the temporal variation of the concentration of particulate matter in the recreational forest and its influencing factors were analyzed by observing the meteorological factors and air negative ions simultaneously and Real-time monitoring of particulate matter concentration,in Zhejiang A&F University.The results showed that there was no significant difference in the average PM1.0 concentration among the six forest communities in the campus;As for PM2.5 concentration level: coniferous and broad-leaved mixed forest> evergreen broad-leaved forest> deciduous broad-leaved forest> Chinese fir forest> Pinus massoniana forest> Bamboo forest;PM10 concentration level: coniferous and broad-leaved mixed forest> Chinese fir forest> Bamboo forest> evergreen broad-leaved forest> deciduous broad-leaved forest> Pinus massoniana forest;The seasonal variation of the three particle size concentrations in the six forest communities was the highest in autumn,followed by spring and lowest in summer;The changes of PM2.5 and PM10 concentrations in the forest communities in autumn were significantly different from those in spring and summer;The lowest PM2.5 concentration of forest communities in spring and autumn is bamboo forest,the lowest concentration of forest communities in summer is Pinus massoniana,the highest PM2.5 concentration of forest communities in the three seasons is coniferous and broad-leaved mixed forest.The daily variation of PM2.5 concentration in the three seasons is similar to the "V" type,the minimum value is in the 12:00-14:00 period,the concentration of 8:00-10:00 is higher than 14:00-16:00 concentration of the time period.The temperature and humidity of the three seasons were significantly correlated with PM1.0,PM2.5 and PM10 concentrations,light intensity,light effective radiation,UV-B radiation,wind speed and the relationship between the three kinds of particle size is not significant.Negative oxygen ion concentration was negatively correlated with temperature,and positively correlated with humidity.There was a significant positive correlation between the three particle size particles and negative oxygen ions in autumn.(2)In the closed,constant temperature and humidity,no wind transparent box PM2.5 concentration changes and PM10 concentration change is very similar.Three groups of experiments are the first 6-10 hours of sharp decline,8-12 hours downward trend is slow,10-14 hours tend to gentle,14 hours after the basic stability;All blank box before the 4-6 hours of sharp decline,6-12 hours slowly rising,7-24 hours slow down,24-26 hours tend to flat.Plants have a purification limit for PM2.5,PM10 and 12 hours after almost no purification effect.The purification of PM2.5 and PM10 in the transparent box is mainly manifested in the descending rate,the time required to reach the specified value and the minimum value after 26 hours.The ability of many plants to purify PM2.5 and PM10 is stronger than that of single plant,when the plant is the same species.The difference analysis showed that there was no significant difference in the purification of PM2.5 and PM10 between single camphor,multi-plant camphor and multi-plant camphor and paulownia combination.There was no significant difference in the purification of PM2.5,PM10 between the single Paulownia and multi-plant Paulownia.There were significant differences in PM2.5 and PM10 between the Single plant camphor,multi-plant camphor,multi-plant camphor and paulownia combination and single Paulownia,multi-plant Paulownia,bank box.There was a significant correlation between PM2.5 and PM10 in the three groups.