Details

Autor(en) / Beteiligte

• Cui, Dongjin
• Li, Xingdi
• Liu, Jianlin
• Yuan, Lei
• Mak, Cheuk Ming
• Fan, Yue
• Kwok, Kenny

Titel

Effects of building layouts and envelope features on wind flow and pollutant exposure in height-asymmetric street canyons

Ist Teil von

• Building and environment, 2021-11, Vol.205, p.108177, Article 108177

Ort / Verlag

Oxford: Elsevier Ltd

Erscheinungsjahr

2021

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• The influences of building layouts on pollutant dispersion within urban street canyons have been widely studied, although they have been rarely considered with envelope features. Different envelope features, such as wing walls, balconies and overhangs, have not yet been quantitatively assessed for their effects on the wind flow patterns around street canyons to a certain degree. Adopting the evaluation indicators of personal intake fraction and daily pollutant exposure, this study aims to investigate the potential influences of building layouts and envelope features that affect pollutant exposure risks for pedestrians and near-road residents via computational fluid dynamics (CFD). The turbulence modelling approach and numerical methods are validated by reported experiments in the literature. Asymmetric street canyons with an aspect ratio of 2 and two typical building layouts, namely, step-up and step-down notch configurations, are further investigated to test their effects. The results indicate that the step-down configuration provides worse situations for wind environments and pollutant dispersion than symmetric and step-up configurations. More specifically, the presence of overhangs has the greatest impact on the personal intake fraction (P_IF) change ratio, followed by balconies. The largest P_IF change ratio occurs on the fifth floor of an upstream building when overhangs are applied to the step-down street canyon. The aforementioned findings are helpful to understand the influences of building layouts together with envelope features on the wind environment as well as pollutant exposure risks experienced by pedestrians and near-road residents. •Influence of different building layouts on pollutant exposure is assessed.•Personal Intake fraction is adopted to evaluate exposure risks quantitatively.•Effect of wing walls on pollutant exposure is lowest.•Balconies have the most evident impact on exposure risks in the step-up canyon.•Overhangs bring the most dramatic change to the values of personal intake fraction in the step-down canyon.