Estimating the real-life infection risk of the SARS-CoV-2 virus in a typical metro compartment

Authors

• Shan Chen
• Ruoyu You
• Qingyan Chen

Document Type

Journal Article

Publication Date

2025

Subject Area

place - asia, place - urban, mode - subway/metro, planning - personal safety/crime, planning - methods, operations - crowding, ridership - commuting

Keywords

Metro, infection risk

Abstract

The metro has been an essential means of commuting for Hong Kong citizens, even during the pandemic. To evaluate the real-life infection risks of airborne SARS-CoV-2 in a typical half-metro carriage, field tests were first carried out to obtain thermo-fluid boundary conditions, air exchange rates, and passenger locations in metro compartments. Computational Fluid Dynamics (CFD) models of half of a metro carriage integrating real-world passenger distribution were built for different crowdedness level with 37, 57, and 75 passengers to determine the infection risk for commuters during typical metro trips. A total of 2449 cases were evaluated, and the study found that the infection risk of SARS-CoV-2 in the benchmark case (one source passenger talking continuously for 26 min in a lightly crowded compartment) varied from 0 % to 7.1 % depending on passenger location, and the corresponding overall infection risk was 1.75 %. No risk existed during a short metro ride of 2 min, and the infection risk increased with the talking durations/coughing frequencies, co-travel durations, and crowdedness levels. The infection risk for seated passengers was higher than that for standing passengers due to the shorter interpersonal distance for the former. Over 80 % of infections occurred within 1.5 m of the source passenger, and 100 % occurred within 2.6 m in metro carriages with different crowdedness levels. A safe social distance of 2.6 m from a potential source passenger is recommended in metro carriages. This study’s findings provide guidelines for safeguarding the health of metro commuters for seasonal illnesses and the future pandemics.

Rights

Permission to publish the abstract has been given by Elsevier, copyright remains with them.

Comments

Sustainable Cities and Society Home Page:

http://www.sciencedirect.com/science/journal/22106707

Recommended Citation

Chen, S., You, R., & Chen, Q. (2025). Estimating the real-life infection risk of the SARS-CoV-2 virus in a typical metro compartment. Sustainable Cities and Society, 106693.