Risk assessment of airborne COVID-19 exposure in social settings

Chin Chun Ooi, Ady Suwardi, Zhong Liang Ou Yang, George Xu, Chee Kiang Ivan Tan, Dan Daniel, Hongying Li, Zhengwei Ge, Fong Yew Leong, Kalisvar Marimuthu, Oon Tek Ng, Shin Bin Lim, Peter Lim, Wai Siong Mak, Wun Chet Davy Cheong, Xian Jun Loh, Chang Wei Kang, Keng Hui Lim

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


The COVID-19 pandemic has led to many countries oscillating between various states of lock-down as they seek to balance keeping the economy and essential services running and minimizing the risk of further transmission. Decisions are made about which activities to keep open across a range of social settings and venues guided only by ad hoc heuristics regarding social distancing and personal hygiene. Hence, we propose the dual use of computational fluid dynamic simulations and surrogate aerosol measurements for location-specific assessment of risk of infection across different real-world settings. We propose a 3-tiered risk assessment scheme to facilitate classification of scenarios into risk levels based on simulations and experiments. Threshold values of 840 viral copies and 40% of original aerosol concentration are chosen to stratify low, medium, and high risk. This can help prioritize allowable activities and guide implementation of phased lockdowns or re-opening. Using a public bus in Singapore as a case study, we evaluate the relative risk of infection across scenarios such as different activities and passenger positions and demonstrate the effectiveness of our risk assessment methodology as a simple and easily interpretable framework. For example, this study revealed that the bus's air-conditioning greatly influences dispersion and increases the risk of certain seats and that talking can result in similar relative risk to coughing for passengers around an infected person. Both numerical and experimental approaches show similar relative risk levels with a Spearman's correlation coefficient of 0.74 despite differing observables, demonstrating applicability of this risk assessment methodology to other scenarios.
Original languageEnglish (US)
JournalPhysics of Fluids
Issue number8
StatePublished - Aug 1 2021
Externally publishedYes

Bibliographical note

Generated from Scopus record by KAUST IRTS on 2023-02-14

ASJC Scopus subject areas

  • Condensed Matter Physics


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