Numerical investigations of urban pollutant dispersion and building intake fraction with various 3D building configurations and tree plantings

Li, Qingman, Liang, Jie, Wang, Qun, Chen, Yuntong, Yang, Hongyu, Ling, Hong, Luo, Zhiwen ORCID: https://orcid.org/0000-0002-2082-3958 and Hang, Jian 2022. Numerical investigations of urban pollutant dispersion and building intake fraction with various 3D building configurations and tree plantings. International Journal of Environmental Research and Public Health 19 (6) , 3524. 10.3390/ijerph19063524

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Abstract

Rapid urbanisation and rising vehicular emissions aggravate urban air pollution. Outdoor pollutants could diffuse indoors through infiltration or ventilation, leading to residents’ exposure. This study performed CFD simulations with a standard k-ε model to investigate the impacts of building configurations and tree planting on airflows, pollutant (CO) dispersion, and personal exposure in 3D urban micro-environments (aspect ratio = H/W = 30 m, building packing density λp = λf = 0.25) under neutral atmospheric conditions. The numerical models are well validated by wind tunnel data. The impacts of open space, central high-rise building and tree planting (leaf area density LAD= 1 m2/m3) with four approaching wind directions (parallel 0° and non-parallel 15°, 30°, 45°) are explored. Building intake fraction is adopted for exposure assessment. The change rates of demonstrate the impacts of different urban layouts on the traffic exhaust exposure on residents. The results show that open space increases the spatially-averaged velocity ratio (VR) for the whole area by 0.40–2.27%. Central high-rise building (2H) can increase wind speed by 4.73–23.36% and decrease the CO concentration by 4.39–23.00%. Central open space and high-rise building decrease under all four wind directions, by 6.56–16.08% and 9.59–24.70%, respectively. Tree planting reduces wind speed in all cases, raising by 14.89–50.19%. This work could provide helpful scientific references for public health and sustainable urban planning.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Architecture
Additional Information:	This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/)
Publisher:	MDPI
ISSN:	1661-7827
Date of First Compliant Deposit:	10 August 2022
Date of Acceptance:	12 March 2022
Last Modified:	23 May 2023 22:57
URI:	https://orca.cardiff.ac.uk/id/eprint/151639

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