Air flow and pollution in a real, heterogeneous urban street canyon: A field and laboratory study

Karra, Styliani; Malki-Epshtein, Liora; Neophytou, Marina

doi:10.1016/j.atmosenv.2017.06.035

Cited by 38 publications

(28 citation statements)

References 29 publications

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“…Uso e ocupação do solo Beelen et al, 2010;Sider et al, 2013;Hong e Goodchild, 2014;Weber et al, 2014;Rodríguez et al, 2016;Zhang et al, 2018 Gabarito das edificações Volume de tráfego Taseiko et al, 2009;Richmond-Bryant et al, 2011;Richmond-Bryant e Reff, 2012;EeXens et al, 2013;Bender e Dziedzic, 2014;Karra et al, 2017Beevers e Carslaw et al, 2005Yuval et al,. 2008;Zhang e Ba[erman, 2013;Rakowska et al, 2014;Zhou et al, 2014;Liu et al, 2017 De acordo com Zhang et al (2018), as emissões de poluentes oriundas dos transportes estão relacionadas aos padrões de uso do solo, que afetam a con iguração urbana impactando na ge-ração de viagens, alterando os nıveis de poluição.…”

Section: Fatores Referênciaunclassified

“…Através desses dois aspectos pode-se avaliar a forma da superfıćie edi icada, que é calculada pela razão entre a altura das edi icações (A) e a largura da via urbana (L) (Oke, 1988;Sousa et al, 2015;Aguiar et al, 2017). Karra et al (2017) avaliaram a in luência da heterogeneidade das edi icações e da variabilidade dos ventos para a dispersão de poluentes atmosféricos. Nesse estudo, os autores constataram que a heterogeneidade no uso do solo, no padrão de gabarito das edi icações, di iculta a dissipação dos gases poluentes, pois esta favorece a formação dos cânions urbanos.…”

Section: Fatores Referênciaunclassified

“…A in luência macro está relacionada à concentração de poluentes em um nıvel agregado de informação, ou seja, sem isolar, nem correlacionar os fatores que in luenciam as concentrações dos poluentes presentes no ambiente. Para uma análise micro leva-se em consi-deração a in luência de fatores de forma desagregada, ou seja, busca-se relações causais entre a emissão, concentração e a dispersão dos poluentes (Karra et al, 2017;Liu et al, 2017;Zhang et al, 2018).…”

Section: Fatores Referênciaunclassified

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Compreensão da formação de NO2 proveniente das operações de transporte urbano e suas relações com agentes causais

et al. 2019

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Os problemas oriundos da mobilidade urbana estão relacionados ao crescimento acelerado e não planejado das cidades, à distribuição espacial das atividades, ao crescimento expressivo do uso do automóvel, as deficiências do transporte público e a ocorrência de impactos negativos nos âmbitos sociais e ambientais, tendo como um dos principais impactos a concentração de NO2. Dessa forma, o presente trabalho tem por objetivo avaliar a influência dos fatores (gabarito das edificações, uso do solo e volume de tráfego) nas concentrações de NO2. Para tal, a complexidade do uso do solo urbano foi traduzida por meio do indicador que mede a diversidade do uso do solo urbano, entropia. As concentrações de NO2 foram medidas através de um método de amostragem passiva. Como principais resultados verificou-se que o volume de tráfego veicular aliado a elevada entropia se relacionam diretamente com as concentrações de NO2. O gabarito das edificações se relaciona com estas concentrações mas não de forma tão direta, pois tal fator pode ser suprimido pelo tráfego veicular ou influenciado por fenômenos naturais que facilitam ou não a dispersão de NO2.

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Section: Fatores Referênciaunclassified

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Compreensão da formação de NO2 proveniente das operações de transporte urbano e suas relações com agentes causais

et al. 2019

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“…For indoor airflow, the challenges are represented by (1) the potentially large variations in turbulence levels with can include low-Reynolds effects and relaminarization of the flow; (2) the wide range of spatial scales from the length scale of the room to the details of inlet and outlet openings Salizzoni et al 2009;Tsang et al 2012;Conan et al 2012;Tominaga andBlocken 2015, 2016;Ricci et al 2017a), water channel measurements (e.g. Princevac 2010;Pournazeri et al 2012;Cruz-Salas et al 2014;Neophytou et al 2014;Karra et al 2017) or water tank experiments (e.g. Linden et al 1990Linden et al , 1999Hunt and Linden 1999;Bolster and Linden 2007;Livermore and Woods 2007;Yu et al 2007;Tapsoba et al 2007;Kang and Lee 2008;Morsing et al 2008;Chen 2009;Etheridge 2011;Thomas et al 2011;van Hooff et al 2012a,b;Partridge and Linden 2013;Khayrullina et al 2017).…”

Section: Introductionmentioning

confidence: 99%

LES over RANS in building simulation for outdoor and indoor applications: A foregone conclusion?

2018

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Large Eddy Simulation (LES) undeniably has the potential to provide more accurate and more reliable results than simulations based on the Reynolds-averaged Navier-Stokes (RANS) approach. However, LES entails a higher simulation complexity and a much higher computational cost. In spite of some claims made in the past decades that LES would render RANS obsolete, RANS remains widely used in both research and engineering practice. This paper attempts to answer the questions why this is the case and whether this is justified, from the viewpoint of building simulation, both for outdoor and indoor applications. First, the governing equations and a brief overview of the history of LES and RANS are presented. Next, relevant highlights from some previous position papers on LES versus RANS are provided. Given their importance, the availability or unavailability of best practice guidelines is outlined. Subsequently, why RANS is still frequently used and whether this is justified or not is illustrated by examples for five application areas in building simulation: pedestrian-level wind comfort, near-field pollutant dispersion, urban thermal environment, natural ventilation of buildings and indoor airflow. It is shown that the answers vary depending on the application area but also depending on other-less obvious-parameters such as the building configuration under study. Finally, a discussion and conclusions including perspectives on the future of LES and RANS in building simulation are provided.

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“…In particular, there have been many studies assuming flat-roof buildings throughout the length of the street, for example, Uehara et al (2000), Gu et al (2011), Wen et al (2013), Guillas et al (2014) and Gromke and Blocken (2015). Karra et al (2017) model a series of consecutive street canyons in a water channel in the laboratory and visualise with PLIF and PIV both the velocities and the release of dye from the center of the street.…”

Section: Introductionmentioning

confidence: 99%

A parametric study of the effect of roof height and morphology on air pollution dispersion in street canyons

Wen

Malki-Epshtein

2018

Journal of Wind Engineering and Industrial Aerodynamics

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 Parametric study of airflow and pollution in street canyons of different morphologies  Conventional pitched roofs increase pollution concentration for most morphologies  Pollution and airflow sensitive to roof slope and roof arrangement morphology  Morphology of upstream streets affects pollution concentration downstream  Interaction between parameters complex; results are variable and case specific ABSTRACT We investigate the effect of conventional pitched roofs on ventilation and pollution in street canyons using Computational Fluid Dynamics and a parametric approach. We studied parallel street canyons with several street morphologies, created by assigning a set of streets with pitched roofs, and varying their pitch and arrangement for three different height-to-width aspect ratios. The distribution of flow properties and pollution concentrations within the street canyons are examined and the effect of different parameter combinations is assessed. We find the relationship between these properties and the street morphology to be complex and case specific. For most morphologies, the pitched roofs lead to higher average pollution concentrations, and in some cases to pollution hotspots near emission sources especially on the leeward side. The pitched roofs are rarely beneficial to ventilation of the street canyons, but a few roof arrangements lead to reduced concentrations on the windward side. Roof slope is shown to significantly relate to both average pollution concentrations and their distribution inside the street; in some street geometries more than others. The results have implications for pedestrian and residential pollution exposure, and for conservation of building facades on historical buildings.

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Air flow and pollution in a real, heterogeneous urban street canyon: A field and laboratory study

Abstract: 9In this work we investigate the influence of real world conditions, including heterogeneity and natural variability of 10 background wind, on the air flow and pollutant concentrations in a heterogeneous urban street canyon using both

Cited by 38 publications

References 29 publications

Compreensão da formação de NO2 proveniente das operações de transporte urbano e suas relações com agentes causais

Compreensão da formação de NO2 proveniente das operações de transporte urbano e suas relações com agentes causais

LES over RANS in building simulation for outdoor and indoor applications: A foregone conclusion?

A parametric study of the effect of roof height and morphology on air pollution dispersion in street canyons

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