Monitoring carbon dioxide to quantify the risk of indoor airborne transmission of COVID-19
Name
monitoring-carbon-dioxide-to-quantify-the-risk-of-indoor-airborne-transmission-of-covid-19.pdf
Description
Published version
Size
1.04 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Bazant, Martin Z
Kodio, Ousmane
Cohen, Alexander E
Khan, Kasim
Gu, Zongyu
Bush, John WM
Date Issued
2021
Journal
Flow
Publisher
Cambridge University Press (CUP)
Citation
Bazant, Martin Z, Kodio, Ousmane, Cohen, Alexander E, Khan, Kasim, Gu, Zongyu et al. 2021. "Monitoring carbon dioxide to quantify the risk of indoor airborne transmission of COVID-19." Flow, 1.
Version
Final published version
Abstract
A new guideline for mitigating indoor airborne transmission of COVID-19 prescribes a limit on the time spent in a
shared space with an infected individual (Bazant & Bush, Proceedings of the National Academy of Sciences of the
United States of America, vol. 118, issue 17, 2021, e2018995118). Here, we rephrase this safety guideline in terms of
occupancy time and mean exhaled carbon dioxide (CO2) concentration in an indoor space, thereby enabling the use
of CO2 monitors in the risk assessment of airborne transmission of respiratory diseases. While CO2 concentration is
related to airborne pathogen concentration (Rudnick & Milton, Indoor Air, vol. 13, issue 3, 2003, pp. 237–245), the
guideline developed here accounts for the different physical processes affecting their evolution, such as enhanced
pathogen production from vocal activity and pathogen removal via face-mask use, filtration, sedimentation and
deactivation. Critically, transmission risk depends on the total infectious dose, so necessarily depends on both the
pathogen concentration and exposure time. The transmission risk is also modulated by the fractions of susceptible,
infected and immune people within a population, which evolve as the pandemic runs its course. A mathematical
model is developed that enables a prediction of airborne transmission risk from real-time CO2 measurements.
Illustrative examples of implementing our guideline are presented using data from CO2 monitoring in university
classrooms and office spaces.
MIT Department
Massachusetts Institute of Technology. Department of Mathematics
Terms of Use
Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1017/FLO.2021.10
