As public health concerns have increased due to the rising number of studies linking adverse health effects with exposures to traffic-related pollution near large roadways, interest in methods to mitigate these exposures have also increased. Several studies have investigated the use of roadside features in reducing near-road air pollution concentrations since this method is often one of the few short-term options available to reduce near-road air pollution. Since roadside vegetation has other potential benefits, the impact of this feature has been of particular interest. The literature has been mixed on whether roadside vegetation reduces nearby pollutant concentrations or whether this feature has no effect or even potentially increases downwind pollutant concentrations. However, these differences in study results highlight key characteristics of the vegetative barrier that can result in pollutant reductions or increase local pollutant levels. This paper describes the characteristics of roadside vegetation that previous research shows can result in improved local air quality, as well as identify characteristics that should be avoided in order to protect from unintended increases in nearby concentrations. These design conditions include height, thickness, coverage, porosity/density, and species characteristics that promote improved air quality. These design considerations can inform highway departments, urban and transportation planners, and developers in understanding how best to preserve existing roadside vegetation or plant vegetative barriers in order to reduce air pollution impacts near transportation facilities.

中文翻译：

---

路边植被设计可改善本地和近路空气质量。

由于越来越多的研究将不良健康影响与大型道路附近交通相关污染的暴露联系起来，从而使公众对健康的关注增加，因此人们对减轻这些暴露的方法的兴趣也日益增加。数项研究已经研究了使用路边特征来减少近距离道路空气污染的浓度，因为这种方法通常是可用于减少近距离道路空气污染的少数短期选择之一。由于路边植被还有其他潜在的好处，因此特别关注此功能的影响。关于路边植被是否会降低附近的污染物浓度，或者此功能是否没有影响甚至可能增加顺风的污染物浓度，文献不一。然而，研究结果中的这些差异突出了营养屏障的关键特征，可导致污染物减少或当地污染物水平升高。本文描述了先前研究表明可以改善当地空气质量的路边植被特征，并确定了应避免的特征，以防止附近浓度意外增加。这些设计条件包括高度，厚度，覆盖率，孔隙率/密度以及可改善空气质量的物种特征。这些设计考虑因素可以使公路部门，城市和交通规划人员以及开发商了解如何最好地保护现有的路边植被或植物生长屏障，以减少交通设施附近的空气污染影响。