Imperial College London, Centre for Environmental Policy, UK.
Imperial College London, Centre for Environmental Policy, UK.
Environ Pollut. 2021 Jan 15;269:116104. doi: 10.1016/j.envpol.2020.116104. Epub 2020 Nov 24.
Global urban planning has promoted green infrastructure (GI) such as street trees, shrubs or other greenspace in order to mitigate air pollution. Although considerable attention has been paid to understanding particulate matter (PM) deposition on GI, there has been little focus on identifying which leaf traits might maximise airborne PM removal. This paper examines existing literature to synthesize the state of knowledge on leaf traits most relevant to PM removal. We systematically reviewed measurement studies that evaluated particulate matter accumulated on leaves on street trees, shrubs green roofs, and green walls, for a variety of leaf traits. Our final selection included 62 papers, most from field studies and a handful from wind tunnel studies. The following were variously promoted as useful traits: coniferous needle leaves; small, rough and textured broadleaves; lanceolate and ovate shapes; waxy coatings, and high-density trichomes. Consideration of these leaf traits, many of which are also associated with drought tolerance, may help to maximise PM capture. Although effective leaf traits were identified, there is no strong or consistent evidence to identify which is the most influential leaf trait in capturing PM. The diversity in sampling methods, wide comparison groups and lack of background PM concentration measures in many studies limited our ability to synthesize results. We found that several ancillary factors contribute to variations in the accumulation of PM on leaves, thus cannot recommend that selection of urban planting species be based primarily on leaf traits. Further research into the vegetation structural features and standardization of the method to measure PM on leaves is needed.
全球城市规划推动了绿色基础设施（GI）的发展，例如街道树木、灌木或其他绿地，以减轻空气污染。尽管人们已经相当关注了解颗粒物（PM）在 GI 上的沉积，但对于哪些叶片特征可能最大限度地去除空气中的 PM 却关注甚少。本文考察了现有文献，以综合有关与 PM 去除最相关的叶片特征的知识状况。我们系统地审查了评估街道树木、灌木、绿色屋顶和绿色墙壁上叶片上积累的颗粒物的测量研究，这些研究评估了各种叶片特征。我们的最终选择包括 62 篇论文，其中大部分来自实地研究，少数来自风洞研究。以下是被认为具有有用特征的叶片特征：针叶状的针叶；小而粗糙和有纹理的阔叶；披针形和卵形；蜡质涂层和高密度的毛状体。考虑到这些叶片特征，其中许多特征也与耐旱性有关，可能有助于最大限度地捕获 PM。虽然已经确定了有效的叶片特征，但没有强有力的或一致的证据可以确定哪种叶片特征在捕获 PM 方面最具影响力。由于许多研究中采样方法的多样性、广泛的比较组和缺乏背景 PM 浓度测量，我们无法综合结果。我们发现，有几个辅助因素会导致叶片上 PM 积累的变化，因此不能建议主要根据叶片特征来选择城市种植物种。需要进一步研究植被结构特征，并对叶片上 PM 测量方法进行标准化。
