A new approach for roughness representation within urban dispersion models. (15th August 2022)

• Record Type: Journal Article
• Authors: Di Nicola, F.; Brattich, E.; Di Sabatino, S.
• Is Part Of: Atmospheric environment. Volume 283(2022)
• Publication Date: 2022-08-15
• Subjects: Green infrastructure -- Air quality -- Vegetation -- Trees -- ADMS dispersion Model; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2022.119181
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: The effects of green infrastructure on pollutant concentrations are greatly variable, essentially depending on the surrounding built-up environment and on local meteorological conditions. To simulate the effects of the presence of trees at urban scale, a reliable methodology is the Computational Fluid Dynamics (CFD) approach, however it needs high calculation costs. An alternative integral dispersion model is given by provided that a suitable parameterization for vegetation is included. In this work, we have developed and demonstrated a novel methodology, based on aerodynamic parameters, to include the aerodynamic effect of trees in an operational dispersion model, the ADMS-Urban. The aerodynamic parameters were derived using the morphometric method starting from open data containing information on buildings and trees. The new roughness parameter calculation method has produced the urban spatially varying roughness (USVR) and it was evaluated in different scenarios at the urban and neighborhood scale. The numerical outputs of the simulations were compared with observations from reference air quality stations collected within an ad-hoc intensive field campaign conducted in 2017 in the city of Bologna, Italy. The results of the comparison highlight that the introduction of the aerodynamic effects of buildings lead to great improvements in the performance of the model at both spatial scales and for the different study sites considered in this study. Conversely, the inclusion of trees in the calculation produces significant improvements only when conducting studies at high spatial resolution and for densely vegetated areas. Highlights: Novel methodology to include the aerodynamic effect of buildings and trees in an operational dispersion model. Evaluation of the performance of the model in different scenarios at the urban and neighborhood scale. The addition of detailed aerodynamic effects generally improves the performance of the dispersion model. The inclusion of trees improves the performance especially at high spatial resolution and for densely vegetated areas.