Possible high COVID-19 airborne infection risk in deep and poorly ventilated 2D street canyons

Lavor, Vitor, Coceal, Omduth, Grimmond, Sue, Hang, Jian and Luo, Zhiwen ORCID: https://orcid.org/0000-0002-2082-3958 2023. Possible high COVID-19 airborne infection risk in deep and poorly ventilated 2D street canyons. Building Simulation 16 , pp. 1617-1628. 10.1007/s12273-023-1037-x

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Abstract

Despite the widespread assumption that outdoor environments provide sufficient ventilation and dilution capacity to mitigate the risk of COVID-19 infection, there is little understanding of airborne infection risk in outdoor urban areas with poor ventilation. To address this gap, we propose a modified Wells-Riley model based on the purging flow rate (QPFR), by using computational fluid dynamic (CFD) simulations. The model quantifies the outdoor risk in 2D street canyons with different approaching wind speeds, urban heating patterns and aspect ratios (building height to street width). We show that urban morphology plays a critical role in controlling airborne infectious disease transmission in outdoor environments, especially under calm winds; with deep street canyons (aspect ratio > 3) having a similar infection risk as typical indoor environments. While ground and leeward wall heating could reduce the risk, windward heating (e.g., windward wall ~10 K warmer than the ambient air) can increase the infection risk by up to 75%. Our research highlights the importance of considering outdoor infection risk and the critical role of urban morphology in mitigating airborne infection risk. By identifying and addressing these risks, we can inform measures that may enhance public health and safety, particularly in densely populated urban environments.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Architecture
Publisher:	Springer
ISSN:	1996-3599
Funders:	NERC
Date of First Compliant Deposit:	19 June 2023
Date of Acceptance:	30 April 2023
Last Modified:	07 Nov 2023 04:25
URI:	https://orca.cardiff.ac.uk/id/eprint/160457

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