Exhaled CO<sub>2</sub> as a COVID-19 Infection Risk Proxy for Different Indoor Environments and Activities

Peng, Zhe; Jimenez, José L.

doi:10.1021/acs.estlett.1c00183

Cited by 244 publications

(242 citation statements)

References 27 publications

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“…For the purpose of estimating the probability of airborne transmission of an infectious agent indoors the equation called the Wells-Riley model represented by the following equation 11) is widely used. claimed that the exhaled CO2 can be treated as a COVID-19 infection risk proxy 9,12,13) .…”

Section: Methodsmentioning

confidence: 99%

Experimental investigation to verify if excessive plastic sheeting shielding produce micro clusters of SARS-CoV-2

Ishigaki

Kawauchi

Yokogawa

et al. 2021

Preprint

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We experimentally investigated indoor air ventilation using the CO2 tracer technique to verify the infection cluster of SARS-CoV-2 that erupted at an office space. Multi-placed observations revealed extremely low air change rates (0.1/h) at the site. The local infection clusters were observed several meters away from a door that is the only ventilation in the office, which suggests a negative effect of plastic sheeting shielding. The thermo-fluid simulation showed that the plastic sheet blocked the airflow and trapped the exhaled air in each partition cell. As risk suppression methods, improving air ventilation by opening windows and using fans were verified, and significant improvements (10-28/h) were observed for each partition cells.

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Section: Methodsmentioning

confidence: 99%

Experimental investigation to verify if excessive plastic sheeting shielding produce micro clusters of SARS-CoV-2

Ishigaki

Kawauchi

Yokogawa

et al. 2021

Preprint

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“…Those types of considerations should be included when specific use recommendations are being made. Such efforts are already underway 24,25 .…”

Section: Discussionmentioning

confidence: 99%

Humidity Reduces Rapid and Distant Airborne Dispersal of Viable Viral Particles in Classroom Settings

Skanata

Spagnolo

Metz

et al. 2021

Preprint

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The transmission of airborne pathogens via aerosols is considered to be the main route through which a number of known and emerging respiratory diseases infect their hosts. It is therefore essential to quantify airborne transmission in closed spaces and determine what recommendations should be implemented to minimize the exposure to the pathogen in built environments. We have developed a method to detect viable virus particles from aerosols by using an aerosolized bacteriophage Phi6 in combination with its host Pseudomonas phaseolicola, which when seeded on agar plates acts as a virus detector that can be placed at a range of distances away from the aerosol-generating source. Based on this method we present two striking results: (1) We consistently detected viable phage particles at distances of 18 feet away from the source within 15-minutes of exposure in a classroom equipped with a state of the art HVAC system. (2) Increasing the relative humidity beyond 40% at a maintained temperature of (22.8 ± 0.2) ° C; significantly reduces the risk of transmission. Our method can be used to quantify the exposure to pathogens at various distances from the source for different amounts of time, data which can be used to set safety standards for room capacity and the efficacy of interventions which aim to reduce pathogen levels in closed spaces of specified size and intended use.

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“…), and to understand aerosol transmission modeling for incorporation into more complex models. The model also allows the estimation of the average CO 2 concentration during an activity, as an additional indicator of indoor risk, and to facilitate the investigation of the relationship between infection risk and CO 2 concentrations (38,74). A screenshot of the estimator is shown in Figure SI-1.…”

Section: Calculation Of Risk Parameters For Specific Situationsmentioning

confidence: 99%

Practical Indicators for Risk of Airborne Transmission in Shared Indoor Environments and their Application to COVID-19 Outbreaks

Peng

Rojas

Kropff

et al. 2021

Preprint

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Some infectious diseases, including COVID-19, can be transmitted via aerosols that are emitted by an infectious person and inhaled by susceptible individuals. Although physical distancing effectively reduces short-range airborne transmission, many infections have occurred when sharing room air despite maintaining distancing. We propose two simple parameters as indicators of infection risk for this situation. They combine the key factors that control airborne disease transmission indoors: virus-containing aerosol generation rate, breathing flow rate, masking and its quality, ventilation and air cleaning rates, number of occupants, and duration of exposure. COVID-19 outbreaks show a clear trend in relation to these parameters that is consistent with an airborne infection model, supporting the importance of airborne transmission for these outbreaks. The observed trends of outbreak size vs. risk parameters allow us to recommend values of the parameters to minimize COVID-19 indoor infection risk. All of the pre-pandemic spaces are in a regime where they are highly sensitive to mitigation efforts. Measles outbreaks occur at much lower risk parameter values than COVID-19, while tuberculosis outbreaks are observed at much higher risk parameter values. Since both diseases are accepted as airborne, the fact that COVID-19 is less contagious than measles does not rule out airborne transmission. It is important that future outbreak reports include ventilation information, to allow expanding our knowledge of the circumstances conducive to airborne transmission of different diseases.

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Exhaled CO₂ as a COVID-19 Infection Risk Proxy for Different Indoor Environments and Activities

Cited by 244 publications

References 27 publications

Experimental investigation to verify if excessive plastic sheeting shielding produce micro clusters of SARS-CoV-2

Experimental investigation to verify if excessive plastic sheeting shielding produce micro clusters of SARS-CoV-2

Humidity Reduces Rapid and Distant Airborne Dispersal of Viable Viral Particles in Classroom Settings

Practical Indicators for Risk of Airborne Transmission in Shared Indoor Environments and their Application to COVID-19 Outbreaks

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Exhaled CO2 as a COVID-19 Infection Risk Proxy for Different Indoor Environments and Activities

Cited by 244 publications

References 27 publications

Experimental investigation to verify if excessive plastic sheeting shielding produce micro clusters of SARS-CoV-2

Experimental investigation to verify if excessive plastic sheeting shielding produce micro clusters of SARS-CoV-2

Humidity Reduces Rapid and Distant Airborne Dispersal of Viable Viral Particles in Classroom Settings

Practical Indicators for Risk of Airborne Transmission in Shared Indoor Environments and their Application to COVID-19 Outbreaks

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Exhaled CO₂ as a COVID-19 Infection Risk Proxy for Different Indoor Environments and Activities