The Multi-scale Analysis On The Capability Of Particulate Matter Retention Of Common Green Trees In Beijing

Plant has a certain block and adsorption on atmospheric particulate matter and the capability of particulate matter retention of different tree species is different. In this experiment, we choose six common green tree including Populus X canadensis Moench, Pinus tabulaeformis Carr., Ailanthus altissima, Amygdalus persica L., Cotinus coggygria Scop. and Syringa oblata Lindl.to compare. By comparing the different tree species on the basis of per unite leaf area, per leaf and per plant, we can choose that the capability of particulate matter retention is relatively good. Moreover, the capability of particulate matter retention of the trees in different configuration modes was investigated. The major conclusions are as follows:(1) Different tree species had obvious difference on different particle size of particulate retention. On the whole experiment, the amount of the particulate matter retention between PM2.5 and PM10 was least. In the point of the proportion of the different particulate matter remained by trees, different plants were not the same and the differences of proportions were relatively large. The amount of the particulate matter remained in plants were large, but the amounts of the PM2.5 retention were not larger than PM that because the proportion of PM2.5 was small. However, the plants had larger amounts of the PM2.5 retention which were compared with the plants which had large total amounts of particulate matter retention.(2) Different tree species had significant impact on the amounts of the particulate matter. For the amounts of the particulate matter, pine had significant differences with lilac, peach, sumac and poplar. For the amounts of the PM2.5 retention, pine had significant differences with sumac, cloves, peach, ailanthus and poplar; For the amounts of the PM>10 retention, pine had significant differences with lilac, peach sumac and poplar, but the difference between pine and Ailanthus was not obvious.(3) On the basis of unit leaf area, different tree species had different capability on different particle size retention. For the amounts of the PM retention, the capacity of Chinese pine was strongest, reaching 2.53g/m2. The following were Ailanthus, cloves, sumac and poplar. Also, the particulate matter retention amounts of peach were 0.59g/m2 which were about a quarter of pine; For the amounts of the PM2.5 retention, pine ranked first holdup was 1.39g/m2, the following were Ailanthus, sumac, poplar and peach. The retention amount of peach was 0.27g/m2, about one-fifth of Chinese Pine.(4)On the basis of per leaf, the size of leaf had a direct impact on the amount of the amounts of the particulate matter. For the amounts of the PM retention, cloves> sumac>poplar> Ailanthus> peach> Chinese pine; For the amounts of the PM2.5 retention, the order of the retention was poplar> peach> sumac>lilac>Ailanthus> Chinese pine. Poplar had the biggest retention amounts and the Chinese pine were the least.(5) On the basis of per tree, For the amounts of the PM retention, the retention amounts of Ailanthus were up to 159.2g/strain and the total retention amount of poplar was 144.5g/strain, and the following were sumac, pine, peach and cloves which had only 4.4g/strain. The retention amounts of Ailanthus were 35 times larger than peach; For the amount of the PM2.5 retention, the amounts of poplar were up to 66.3g/strain, and Ailanthus, sumac, Chinese pine and peach were at middle. Also, the retention amounts of the clove were 1.52g/strain and the amounts of the PM2.5 retention of poplar were 43 times larger than clove.(6) On the basis of the three different configuration mode, the order of them was arbor-shrub> shrub> arbor. Furthermore, the capability of the retention amount of mixed-forest was bigger than pure forest. In heavily polluted weather, arbor-shrub and shrub had significant lowing effect on PM2.5, but they were ineffective in PM10.