Abstract

This paper first discusses the aerodynamic effects of trees on local scale flow and pollutant concentrationin idealized street canyon configurations by means of laboratory experiments and Computational FluidDynamics (CFD). These analyses are then used as a reference modelling study for the extension a theneighbourhood scale by investigating a real urban junction of a medium size city in southern Italy.A comparison with previous investigations shows that street-level concentrations crucially depend onthe wind direction and street canyon aspect ratio W/H (with W and H the width and the height ofbuildings, respectively) rather than on tree crown porosity and stand density. It is usually assumed in theliterature that larger concentrations are associated with perpendicular approaching wind. In this study,we demonstrate that while for tree-free street canyons under inclined wind directions the larger theaspect ratio the lower the street-level concentration, in presence of trees the expected reduction ofstreet-level concentration with aspect ratio is less pronounced.Observations made for the idealized street canyons are re-interpreted in real case scenario focusing onthe neighbourhood scale in proximity of a complex urban junction formed by street canyons of similaraspect ratios as those investigated in the laboratory. The aim is to show the combined influence ofbuilding morphology and vegetation on flow and dispersion and to assess the effect of vegetation onlocal concentration levels. To this aim, CFD simulations for two typical winter/spring days show that treescontribute to alter the local flow and act to trap pollutants. This preliminary study indicates that failing toaccount for the presence of vegetation, as typically practiced in most operational dispersion models,would result in non-negligible errors in the predictions.

Autore Pugliese

• Ielpo Pierina

Tutti gli autori

• Buccolieri R.; Salim M.S.; Sandra Leo L.; Di Sabatino S.; Chan A.; Ielpo P.; De Gennaro G.; Gromke C.

Titolo volume/Rivista

Atmospheric environment

Anno di pubblicazione

2011

ISSN

1352-2310

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

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Numero di citazioni Scopus

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Ultimo Aggiornamento Citazioni

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Settori ERC

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Codici ASJC

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