不同树种配置PM2.5动态变化特征

Dynamic characteristics of PM2.5 under different tree species configurations

以北京市大兴区南海子公园26种常见树种配置为研究对象,应用Dustmate手持PM2.5监测仪监测各配置PM2.5,结合气溶胶再发生器和叶面积扫描仪,分析单位叶面积PM2.5吸附量,以综合探讨不同树种配置PM2.5动态变化特征。结果表明:总体上,各树种配置中PM2.5浓度呈现上午高、下午低的趋势,14:00最低。各树种配置中PM2.5平均值表现为针阔混交林>阔叶纯林>阔阔混交林>针叶纯林>针针混交林,且6月>9月>7月>10月>5月>8月。不同树种配置对PM2.5的吸附能力差异较大,表现为针叶纯林>针针混交林>针阔混交林>阔叶纯林>阔阔混交林。因植物吸附PM2.5能力取决于单位叶面积PM2.5吸附量及其叶面积指数,进行树种配置时需同时考虑这两个因素,将不同生活型和具不同叶习性的植物合理混交配置,从而提高植被吸附和调控PM2.5的能力,为优化城市绿化植物配置、降低空气中PM2.5污染提供科学依据。

Taking 26 common vegetation configurations of Nanhaizi Park in Daxing District of Beijing as the research object,the mass concentration of PM2.5 in different configurations was monitored by Dustmate hand-held PM2.5 monitor.Combined with aerosol regenerator and leaf area scanner,PM2.5 adsorption capacity of leaf was analyzed to comprehensively explore the dynamic characteristics of PM2.5 in different vegetation configurations.The results showed that the diurnal variation of PM2.5 concentration in each tree species configuration was high in the morning and low in the afternoon,and lowest at 14:00.The PM2.5 concentration of each tree species configuration was June>September>July>October>May>August.PM2.5 adsorption capacity of different tree species configuration was different,which was shown as pure coniferous forest>coniferous mixed forest>coniferous broad-leaved mixed forest>pure broad-leaved forest>broad-leaved mixed forest.Because the ability of plant to adsorb PM2.5 depended on the amount of PM2.5 per unit leaf area and its leaf area index,these two factors should be taken into account in rational tree species configuration.Plants with different life forms and different leaf habits should be mixed to improve the ability of vegetation to adsorb and regulate PM2.5,so as to provide scientific basis for optimizing the configuration of urban greening plants and reducing PM2.5 pollution hazards in the air.