| Aero-anion is praised as air vitamin and auxin,just due to its remarkable functions of falling dust,restraining fungi and bacteria,purifying the air and regulating the microclimate.As an important factor of forest tourism resource and health management of urban forest,aero-anion level has been an important index in evaluating pureness of urban air and environment quality.During July 2007 and March 2008,taking palm plant community in Xiamen as object,measured the concentration of aero-cation and aero-anion.The observation data were qualitatively and quantitatively analyzed using tabulation,graph and multi-variables statistical methods such as variance and correlation analysis.This paper discussed diurnal change and annual variation of aero-anion,aero-anion level comparison in the same plant community structure by tree and fodder grass and different configuration types of plant communities,as well as hydrostatic and meteorological factors(air temperature,air humidity,wind speed)on the aero-anion impact.By the following,there are changes and conclusions of law of aero-anion concentration:(1)The research of annual variation of aero-anion in palm plant communities indicates that the concentration of aero-anion ascend after descend from July to next March.The highest concentration of aero-anion appears in July with 1046 lons.cm-3, which is 2.3 times more than the lowest appears in December.Concentration of aero-anion reaches the highest in summer,while autumn's is higher than spring's.It is the lowest in winter.The curve of single grade coefficient(q)and evaluating index of air quality(CI)are symmetrical.The lower q is,the higher CI is.CI reached its peak in September and then the air quality is best.(2)There are some differences in the diurnal variation of aero-anion concentration in different seasons.As a whole,it shows a phenomenon of fluctuation.There are 2-3 peaks mainly appear at 8:00am-10:00am,18:00pm-20:00pm,and 2:00am-4:00am. The peak may appear at 12:00am in winter also.The highest value of peak usually appears at 2:00am.There are 1-2 wave troughs mainly appear at 14:00pm and 22:00pm.The loweest value of wave trough usually appears at 14:00pm.The variation amplitude of aero-anion concentration increases at 22:00pm. (3)Aero-anion concentration of plant communities with the same structure by tree and fodder grass reaches significant level at 5%.Further analysis show that it is just to be significant difference in spring,no significant difference in summer and winter,and significant difference in autumn.From that,it can be showed that concentration of air-anion in autumn contributes greatest on the significant difference.(4)The aero-anion concentration in the four different configuration type of palm plant community reaches the extremely significant level at 1%.The four communities are with tree,shrub and fodder grass,tree and fodder grass,tree and shrub,and comparison plot.Significant correlation doesn't exist between community by tree and fodder grass and by tree and shrub.The order of aero-anion concentration and air pureness gradation is Community with tree,shrub and fodder grass＞Community with tree and fodder grass＞Community with tree and shrub＞controls.It indicates that the air quality of community by tree,shrub and fodder grass is the best.(5)Aero-anion concentration and air pureness gradation in inner palm plant community was higher than the edge.The aero-anion concentration is nearly 2 times more than the edge of palm plant community.And the air pureness is 1-2 higher gradations than the edge of palm plant community.(6)In different extent,aero-anion concentration and air pureness gradation of 5m off Static water was higher than 1m in four seasons.It is likely that this distance is influenced by not only the diffusion of aero-anion from water off 5m,but also the diffusion of aero-anion from plant community beyond 5m.(7)Aero-anion concentration has no correlation with air temperature and wind speed, but has significant positive correlation with relative humidity.And aero-anion concentration increases with the increase of relative humidity in relative humidity range of validity.
|
PDF Full Text Request