Cambridge Environmental Research Consultants , Cambridge, UK.
Department of Chemical Engineering and Biotechnology, University of Cambridge , Cambridge, UK.
J Air Waste Manag Assoc. 2021 Feb;71(2):247-267. doi: 10.1080/10962247.2020.1803158.
A street canyon pollution dispersion model is described which accounts for a wide range of canyon geometries including deep and/or asymmetric canyons. The model uses up to six component sources to represent different effects of street canyons on the dispersion of road traffic emissions. The final concentration is a weighted sum of the component concentrations dependent on output point location; canyon geometry; and wind direction relative to canyon orientation. Conventional approaches to modeling pollution in street canyons, such as the "Operational Street Pollution Model" (OSPM), do not account for canyons with high aspect ratios, pavements, and building porosity, so are not applicable for all urban morphologies. The new model has been implemented within the widely used, street-level resolution ADMS-Urban air quality model, which is used for air quality assessment and forecasting in cities such as Hong Kong where high-rise buildings form deep and complex street canyons. The new model is evaluated in relation to measured pollutant concentration data from the "Optimisation of modelling methods for traffic pollution in streets" (TRAPOS) project and routine measurements from 42 monitoring sites in London. Comparisons have been made between modeling using the new canyon model; a simpler approach to canyon modeling based on the OSPM formulation; and without any inclusion of canyon effects. The TRAPOS dataset has been used to highlight the model's ability to replicate the dependence of concentration on wind speed and direction, and also to show improved model performance for the prediction of high concentration values, which is particularly important for model applications such as planning and assessment. The London dataset, in which the street canyons are less well defined, has also been used to demonstrate improved model performance for this advanced approach compared to the simpler methods, by categorizing the measurement locations according to site type (background, near-road, and strong canyon). : Currently available air dispersion models do not allow for a number of geometric features that influence air dispersion within street canyon environments. The new advanced street canyon model described in this paper accounts for: emissions from each road carriageway separately; canyon asymmetry; canyon porosity; and pavements. The extensive model evaluation presented shows that the new model demonstrates good performance, better than more basic approaches in which the complex geometries that define "canyons" are neglected.
描述了一种街道峡谷污染扩散模型，该模型考虑了广泛的峡谷几何形状，包括深峡谷和/或不对称峡谷。该模型使用多达六个分量源来表示街道峡谷对道路交通排放扩散的不同影响。最终浓度是依赖于输出点位置、峡谷几何形状和相对于峡谷方向的风向的分量浓度的加权和。用于建模街道峡谷污染的传统方法，例如“操作型街道污染模型”（OSPM），没有考虑高纵横比、铺面和建筑孔隙率的峡谷，因此不适用于所有城市形态。新模型已在广泛使用的街道级分辨率 ADMS-Urban 空气质量模型中实施，该模型用于空气质量评估和预测，例如在香港等城市，高层建筑形成了深而复杂的街道峡谷。新模型是根据“街道交通污染建模方法优化”（TRAPOS）项目的测量污染物浓度数据和伦敦 42 个监测站点的常规测量数据进行评估的。比较了使用新峡谷模型、基于 OSPM 公式的更简单的峡谷建模方法以及不包括峡谷影响的建模方法的结果。TRAPOS 数据集用于突出模型复制浓度对风速和风向的依赖关系的能力，还用于展示预测高浓度值的改进模型性能，这对于规划和评估等模型应用特别重要。伦敦数据集的街道峡谷定义不明确，也用于证明与更简单的方法相比，这种先进方法的模型性能有所提高，方法是根据站点类型（背景、近路和强峡谷）对测量位置进行分类。：目前可用的空气扩散模型不允许存在许多影响街道峡谷环境中空气扩散的几何特征。本文描述的新的高级街道峡谷模型考虑了以下因素：每一条车行道的单独排放；峡谷不对称；峡谷孔隙率；以及铺面。所呈现的广泛模型评估表明，新模型的性能良好，优于忽略定义“峡谷”的复杂几何形状的更基本方法。
