摘要:现阶段植物滞尘作为治理大气颗粒物污染的有效方法已被广泛接受与应用。已有研究表明，降雨等方式对植物叶表面颗粒物的滞留有着显著的影响，可有效地将颗粒物从叶表面去除，使植物再次具有滞留颗粒物的能力。由于自然降雨难以量化，现有研究大多采用模拟降雨的方式，将降雨特性量化为降雨强度、降雨历时等可控变量，但较少将降雨高度这一变量纳入研究。且大多以森林生态系统或者城市生态系统中常见的乔、灌、草等植物为主要研究对象，而忽略了处于水陆过渡带的湿地生态系统中植物的特殊性。湿地生态系统不仅可通过植物叶片等结构滞留颗粒物，还可依靠增强空气相对湿度促进颗粒物的吸收和积累，导致湿地植物滞尘规律的特殊性。因此，选择北京地区湿地生态系统内的4种常见植物（香蒲、菖蒲、芦苇和黄花鸢尾）作为研究对象，通过人工模拟降雨的方式，将降雨特性量化为降雨高度与降雨强度两个变量，共设置1 m （11 m）、2 m （10 m）两个不同降雨高度，30 mm/h、45 mm/h、60 mm/h三种不同降雨强度，并将颗粒物划分粗颗粒物（10—100 μm）、细颗粒物（3—10 μm）、超细颗粒物（0.4—3 μm）三种粒径范围。通过滤膜法获得单位叶面积颗粒物去除量，探讨人工降雨对湿地植物叶表面颗粒物滞留的影响。主要研究结果如下：（1）颗粒物去除量在粗颗粒物（10—100 μm）粒径范围内最高；（2）所试4种湿地植物中，菖蒲的颗粒物去除量位居前列；（3）只有在一定的范围内，植物叶表面颗粒物去除量才随降雨强度的增加而增加；（4）不同降雨高度下所试湿地植物叶表面颗粒物去除量无明显规律，降雨高度之间无显著差异（P>0.05）。



Abstract:At the present stage, plant dust retention is widely used as an effective method to control atmospheric particulate pollution. Studies showed that rainfall, with a significant effect on the retention of particulate matter on the leaf surface of plants, could effectively remove particulate matter from the leaf surface and give the leaf surface with the ability to retain particulate matter again. As natural rainfall is difficult to quantify, most existing studies used the simulated rainfall to quantify rainfall characteristics using controllable variables such as rainfall intensity and rainfall duration, but the variable of rainfall height was less commonly included in studies. Most studies focus on plants such as trees, shrubs, and grasses, which are common in forest ecosystems or urban ecosystems, and ignore the special characteristics of plants in wetland ecosystems. Wetland ecosystems not only retain particulate matter through structures such as plant leaves, but also rely on enhancing relative air humidity to promote the uptake and accumulation of particulate matter, leading to the specificity of the dust retention patterns of wetland plants. Thus, this study selected common plants (Typha orientalis., Acorus calamus, Phragmites australis, Iris wilsonii) of the wetland ecosystem in Beijing area as the research object. Through artificial simulation of rainfall, the rainfall characteristics are quantified to two variables, rainfall height and rainfall intensity. Two different rainfall heights were 1 m (11 m) and 2 m (10 m). Three different rainfall intensities included 30 mm/h, 45 mm/h, and 60 mm/h. The particulate matter was divided into three particle size ranges, namely coarse particulate matter(10-100 μm), fine particulate matter(3-10 μm), ultrafine particulate matter(0.4-3 μm). The removed particulate matter per unit leaf area was obtained through the filter membrane method, and the effect of artificial rainfall on the retention of particulate matter on the leaf surface of wetland plants was discussed. The results are as follows:(1) The mass of particulate matter removal was the highest in the range of 10-100 μm, that is, in the coarse particle scale; (2) Among the four wetland plants tested in this study, Acorus calamus ranked the highest in particulate matter removal; (3) The mass of particulate matter removed from plant leaf surfaces increases with increasing rainfall intensity only within a certain range; (4) There was no significant pattern in the removal of particulate matter from the leaf surface of the tested wetland plants with rainfall height, and there was no significant difference between rainfall heights (P>0.05).





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