Effects Of Waterfronts Plant Communities On Meteorological Factors Air Quality

In this study,four water samples were collected from Ningdan Road to Fengdu Road,besides Qinhuai River.Four plant species and 30 species were selected to investigate their plant communities,including plant flora composition,plant species diversity,Community Types and Structural Features.The aerodynamic factors such as wind speed,temperature,humidity and PM2.5,PM 10,air negative oxygen ions and other air quality factors were measured in March,2016-March 2017.The relationship between plant community,environmental factors and the influence of plant community on the relevant environmental factors were analyzed,and the following main conclusions were drawn:(1)Temperature change of the year:summer>spring>autumn>winter,plant cooling effect:summer>spring>autumn>winter;temperature changes in the law:single peak changes,the maximum value of plant cooling is at 12:00-14:00(Spring,autumn and winter)or 10:00(summer);the annual variation of humidity:the highest in summer,the lowest in spring;the ability of humidification in summer is the highest;The daily variation of humidity:"V" type change,plant humidification effect at 14:00(spring,autumn and winter)or 10:00(summer);Change of the year of PM2.5 and PM10:winter>autumn>spring>summer,the regularity of plant reduction is not obvious;daily changes of PM2.5 and PM10:"V" changes,the maximum reduction of plant is at 12:00-14:00(summer,autumn and winter),not obvious in spring;The annual change of negative oxygen ion:summer>autumn>spring>winter,the ability of adjust of plant is not obvious;the daily change of negative oxygen ion:"V type"change(spring and summer)or "single peak"change(autumn and winter),the ability of adjust of plant was "double peak" change(spring,summer,autumn)or "W type "change(winter).(2)There was a significant positive correlation between average height,average crown width and average diameter at both ages.There were positive correlations between species richness,species diversity index,dominance index and species evenness index of plant community.There was a positive correlation between the average height,the average crown and the average diameter of the tree.There was no significant correlation between the ratio of evergreen to leaf,the height of canopy and the height,crown width and DBH of shrubs,there is a negative correlation between wind speed and temperature,humidity,PM2.5,PM10,negative ion concentration.Temperature and humidity,negative oxygen ion concentration negative correlation,humidity and negative oxygen ions are positively correlated.PM2.5,PM 10 and temperature are positively correlated,but the correlation with the humidity is not significant,the correlation with negative oxygen ions were negatively correlated.PM2.5 and PM 10 were significantly positively correlated.(3)The cooling effect of plant community was dominated by tree height and plant species richness index.The humidification of plant community was dominated by tree height,tree diameter at breast height,tree crown,leaf area index,green quantity and plant richness index.The ability of plant community to reduce PM2.5 and PM 10 was closely related to wind speed,but the correlation with tree species and community was not significant.The increase in negative oxygen ion capacity of plant communities was dominated by plant species richness index and Shannon-Wiener index.The increase in negative oxygen ion capacity of plant communities was dominated by plant species richness index and Shannon-Wiener index.In general,the average height,average crown width,average diameter at breast height and green quantity of the trees play a co-dominant role in the impact of the community on environmental factors.(4)There are differences in the effects of plant communities on environmental factors at different distances from water bodies.At 35 meters from the water,the plant community is the worst for the regulation of environmental factors,the temperature,PM2.5 and PM 10 concentrations are the highest,humidity,negative oxygen ion concentration are the lowest.At 5 or 20 meters from the water,the plant community is better regulated by environmental factors.The temperature,PM2.5 and PM 10 are lower,the humidity and negative oxygen ions are higher,but it is better at 20 meters.(5)The ability of plant community to cool and humidify,reduce the ability of PM2.5 and PM 10 concentration,increase the ability of negative oxygen ion concentration is better than the control.The difference of the vertical structure and the different vegetation types was significant,and the difference of the ability of different seasons was significant.The vegetation types with low temperature and good moisturizing effect are deciduous broad-leaved forest(summer),evergreen broad-leaved forest(spring,autumn and winter).The vertical structure of the effect of cooling and moistening is "Tree-herb"(summer),"Tree-shrub-grass"(spring,autumn and winter).The vegetation types of reduced PM2.5 and PM 10 were deciduous coniferous forest(spring and summer),evergreen broad-leaved forest(autumn and winter).Reduced PM2.5 and PM 10 capacity of the vertical structure of the size of the comparison:"Tree-herb" type>"Tree-shrub-grass"type>" Shrub-herb" type>" Single grass" type.Increased negative oxygen ion ability of vegetation types are deciduous coniferous forest(spring),evergreen broad-leaved forest(summer,autumn and winter).Increased vertical oxygen ion capacity of the vertical structure of the size of the comparison:"Tree-herb" type>"Tree-shrub-grass" type>"Shrubs-herb" type>"Single grass" type.