| Urban green space, has the function of air pollutants reduction, such as air purification and balance of the natural ecological systems, which is closely related to community structures. Based on various community structures (arbor-shrub-lawn、arbor、 arbor-lawn、shrub-lawn and lawn) of urban green space. This paper studied on air pollutants reduction of45sample plots in Qingshan area, Wuhan. Data obtained of six indicators(PM2.5、PM5、PM10、TSP、SO2、NO2) presents the relationship between green spaces and air pollution.Pollution removal percentage of green spaces with different structure can also be cacunlated. The correlation analysis of removal percentage and the corresponding structure of samples were also discussed in order to provide reference in contributing the urban green space.The main conclusions of the paper are listed below:(1) From the strongest to the weakest scales, the order of pollution removal percentage can be sorted as follows. PM2.5:arbor-shrub-lawn(58.97%)> arbor-lawn (44.99%)>shrub-lawn(37.57%)>arbor(31.18%)>lawn(18.49%).PM5:arbor-shrub-lawn(47.48%)>arbor-lawn(29.08%)>shrub-lawn(24.07%)>arbor(21.57%)>lawn(21.57%).PM10:ar bor-shrub-lawn(33.75%)>arbor-lawn(25.20%)>shrub-lawn(23.45%)>arbor(19.54%)>law n(11.63%).TSP:arbor-shrub-lawn(30.45%)>shrub-lawn(16.30%)>arbor-lawn(15.00%)>ar bor(14.41%)> lawn(7.07%). By multiple range test, it can be concluded that the community with composite structure can be more efficient than simple community when they remove air pollution.(2)Gaseous pollutants (SO2、NO2) removal percentage of green space with various structure was also measured. SO2:arbor-shrub-lawn (53.74%)、arbor-lawn (50.45%)> shrub-lawn (50.83%)>arbor (48.09%)>lawn (31.18%).NO2:arbor-shrub-lawn (58.75%), arbor-lawn (54.57%)>shrub-lawn (59.94%)> arbor(47.23%)>lawn(33.42%). Green spaces with shrub-lawn structure have the largest removal percentage, which can be used in rodeside where the NO2is the main pollution or the space is limited.(3)PM2.5removal efficiency of green spaces with the same structure is the best, and TSP is the worst, PM10and PM5is centered. And the difference of gaseous pollutants(SO2、NO2) is not obvious(p<0.05).(4) Correlation analysis shows tha these indicators arbor height, arbor clear height, cover degree of arborous layer, arbor density, arbor frequentness, cover degree of shrub layer, shrub density,Shannon-Wiener diversity index and richness index have significant influence on air removal percentage in green spaces with arbor-shrub-lawn structure.(5) The correlation between arbor canopy width, arbor clear heights, cover degree of arborous layer, arbor density, Shannon-Wiener diversity index, richness index and gaseous pollutants (SO2N NO2) removal percentage of green space with arbor structure is significant. And particulate matter removal percentage is mainly affected by arbor clear heights and cover degree.(6)Research on the structure index of arbor-lawn green space affecting the removal of air pollutants, it confirmed that gaseous pollutants SO2、NO2mainly high correlation with the cover of the arbor and clear height, particulate pollutants and arbor height, arbor density and richness index and other indicators have a certain relevance, the impact is different.And there is no correlation with lawn.(7) Structural type of shrub-grass indicator factors and its effect of atmospheric pollutants abate correlation analysis showed that the height of the shrub would affect the gaseous pollutants significantly, the density of the shrub layer and PM2.5, the PM5reduction rate was significant. And some of the other structure indicators affect the content of air pollutant.(8)The study obtained the result there is no correlation between the structure of the lawn structure index and air pollutants decrease. |
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