北京城市森林公园不同树种吸附大气颗粒物能力

【目的】为了了解北京城市森林公园内不同树种对大气颗粒物的吸附能力,筛选出对大气颗粒物有较强吸附能力的绿化造林树种。【方法】选取奥林匹克森林公园内的10个树种,应用气溶胶再发生器测算单位叶面积对不同粒径颗粒物(TSP、PM10、PM2.5和PM1.0)的吸附量,并用扫描电镜获取各树种的叶片表面形态特征。【结果】不同树种单位叶面积对颗粒物的吸附能力存在显著差异,整体表现为针叶树种高于阔叶树种。其中对TSP的吸附能力较强的是油松和白杄,较小的是紫丁香和毛白杨;对PM10吸附能力较强的是白杄、油松,较小的是紫丁香和毛白杨;对PM2.5吸附能力较强的是白杄、油松,较小的是毛白杨和榆叶梅;对PM1.0吸附能力较强的是白杄、油松,较小的是毛白杨和榆叶梅。【结论】针叶树种中,叶表面存在深浅差异明显的细密沟壑以及密集的气孔、绒毛等更有利于叶片对颗粒物的吸附;反之叶表面较为平滑,无明显起伏,不利于吸附颗粒物。总体而言,叶表面具有大量沟槽、气孔的针叶树种较阔叶树种具有更高的吸附量和吸附能力。对大气颗粒物的吸附作用的绿化造林可以优先考虑针叶树种如白杄、油松等。研究结果为揭示不同树种吸附大气颗粒物的机理及合理选择公园绿化树种提供参考。

Study on the atmospheric particulate matters adsorption capacity of different tree species in urban forest park of Beijing

Objective]The study aimed to understand the adsorption capacity of different tree species to atmospheric particulate matters in urban forest park of Beijing to select the afforestation tree species with high adsorption capacity.Methods]Ten tree species including Pinus tabuliformis,Picea meyeri Rehd.et Wils,Juniperus formosana Hayata,Sophora japonica,Populus tomentosa,Fraxinus chinensis,Prunus Cerasifera,Amygdalus triloba,Malus micromalus,and Syringa oblata Lindl were chosen as study objects in the Olympic Forest Park.Using aerosol generator (QRJZFSQ-I) the adsorption amounts of TSP,PM10,PM2.5and PM1.0 per unit leaf area were measured,and the leaf surface morphological characteristics were also analyzed by caning electron microscopy.Results] The results showed that atmospheric particulate matter adsorption capacity of different tree species were different significantly,and the adsorption capacity of coniferous trees was higher than that of broad-leaf trees.For TSP,PM10,PM2.5 and PM1.0,P.tabuliformis and P.meyeri Rehd.et Wils presented the highest adsorption capacity.The TSP and PM10 adsorption capacity of S.oblata Lindl and P.tomentosa were the lowest.For PM2.5 and PM1.0,P.tomentosa,P.Cerasifera exhibited the lowest adsorption capacity.Conclusion] The leaves covered with dense grooves,stomas,and epidermal hairs were beneficial for particulate matter adsorption.On the contrary,the smooth leaves adhered the fewer particulate matters.In summary,the coniferous trees whose leaves was of a large number of grooves and stomas presented higher adsorption capacity and adsorption amount than the broad-leaf trees.In consideration of the adsorption effect of particulate matter,the coniferous trees such as P.tabuliformis and P.meyeri Rehd.et Wils were preferred in afforestation.The results provide reference for revealing the adsorption mechanism of atmospheric particulate matters by different tree species and the rational selection of tree species in the park.