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Stettler MEJ, Nishida RT, de Oliveira PM, Mesquita LCC, Johnson TJ, Galea ER, Grandison A, Ewer J, Carruthers D, Sykes D, Kumar P, Avital E, Obeysekara AIB, Doorly D, Hardalupas Y, Green DC, Coldrick S, Parker S, Boies AM. Source terms for benchmarking models of SARS-CoV-2 transmission via aerosols and droplets. ROYAL SOCIETY OPEN SCIENCE 2022. [PMID: 35592762 DOI: 10.6084/m9.figshare.c.5958950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
There is ongoing and rapid advancement in approaches to modelling the fate of exhaled particles in different environments relevant to disease transmission. It is important that models are verified by comparison with each other using a common set of input parameters to ensure that model differences can be interpreted in terms of model physics rather than unspecified differences in model input parameters. In this paper, we define parameters necessary for such benchmarking of models of airborne particles exhaled by humans and transported in the environment during breathing and speaking.
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Affiliation(s)
- Marc E J Stettler
- Department of Civil and Environmental Engineering, Imperial College London, London SW7 2AZ, UK
| | - Robert T Nishida
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2G8
| | | | - Léo C C Mesquita
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK
| | - Tyler J Johnson
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK
| | - Edwin R Galea
- Fire Safety Engineering Group, University of Greenwich, London SE10 9LS, UK
| | - Angus Grandison
- Fire Safety Engineering Group, University of Greenwich, London SE10 9LS, UK
| | - John Ewer
- Fire Safety Engineering Group, University of Greenwich, London SE10 9LS, UK
| | - David Carruthers
- Cambridge Environmental Research Consultants Ltd, 3 Kings Parade, Cambridge CB2 1SJ, UK
| | | | - Prashant Kumar
- Global Centre for Clean Air Research (GCARE), Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Eldad Avital
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
| | - Asiri I B Obeysekara
- Applied Modelling and Computation Group, Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, UK
| | - Denis Doorly
- Department of Aeronautics, Imperial College London, London SW7 2AZ, UK
| | - Yannis Hardalupas
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK
| | - David C Green
- MRC Centre for Environment and Health, Environmental Research Group, Imperial College London, Michael Uren Biomedical Engineering Hub, London, W12 OBZ, UK
- NIHR HPRU in Environmental Exposures and Health, Imperial College London, Michael Uren Biomedical Engineering Hub, London, W12 OBZ, UK
| | - Simon Coldrick
- Health and Safety Executive, Harpur Hill, Buxton, Derbyshire SK17 9JN UK
| | - Simon Parker
- Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, UK
| | - Adam M Boies
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK
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Stettler MEJ, Nishida RT, de Oliveira PM, Mesquita LCC, Johnson TJ, Galea ER, Grandison A, Ewer J, Carruthers D, Sykes D, Kumar P, Avital E, Obeysekara AIB, Doorly D, Hardalupas Y, Green DC, Coldrick S, Parker S, Boies AM. Source terms for benchmarking models of SARS-CoV-2 transmission via aerosols and droplets. ROYAL SOCIETY OPEN SCIENCE 2022; 9:212022. [PMID: 35592762 PMCID: PMC9066307 DOI: 10.1098/rsos.212022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 04/13/2022] [Indexed: 05/03/2023]
Abstract
There is ongoing and rapid advancement in approaches to modelling the fate of exhaled particles in different environments relevant to disease transmission. It is important that models are verified by comparison with each other using a common set of input parameters to ensure that model differences can be interpreted in terms of model physics rather than unspecified differences in model input parameters. In this paper, we define parameters necessary for such benchmarking of models of airborne particles exhaled by humans and transported in the environment during breathing and speaking.
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Affiliation(s)
- Marc E. J. Stettler
- Department of Civil and Environmental Engineering, Imperial College London, London SW7 2AZ, UK
| | - Robert T. Nishida
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2G8
| | | | - Léo C. C. Mesquita
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK
| | - Tyler J. Johnson
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK
| | - Edwin R. Galea
- Fire Safety Engineering Group, University of Greenwich, London SE10 9LS, UK
| | - Angus Grandison
- Fire Safety Engineering Group, University of Greenwich, London SE10 9LS, UK
| | - John Ewer
- Fire Safety Engineering Group, University of Greenwich, London SE10 9LS, UK
| | - David Carruthers
- Cambridge Environmental Research Consultants Ltd, 3 Kings Parade, Cambridge CB2 1SJ, UK
| | | | - Prashant Kumar
- Global Centre for Clean Air Research (GCARE), Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Eldad Avital
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
| | - Asiri I. B. Obeysekara
- Applied Modelling and Computation Group, Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, UK
| | - Denis Doorly
- Department of Aeronautics, Imperial College London, London SW7 2AZ, UK
| | - Yannis Hardalupas
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK
| | - David C. Green
- MRC Centre for Environment and Health, Environmental Research Group, Imperial College London, Michael Uren Biomedical Engineering Hub, London, W12 OBZ, UK
- NIHR HPRU in Environmental Exposures and Health, Imperial College London, Michael Uren Biomedical Engineering Hub, London, W12 OBZ, UK
| | - Simon Coldrick
- Health and Safety Executive, Harpur Hill, Buxton, Derbyshire SK17 9JN UK
| | - Simon Parker
- Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, UK
| | - Adam M. Boies
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK
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Kriegel M, Hartmann A, Buchholz U, Seifried J, Baumgarte S, Gastmeier P. SARS-CoV-2 Aerosol Transmission Indoors: A Closer Look at Viral Load, Infectivity, the Effectiveness of Preventive Measures and a Simple Approach for Practical Recommendations. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 19:220. [PMID: 35010484 PMCID: PMC8750733 DOI: 10.3390/ijerph19010220] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 12/12/2022]
Abstract
There is uncertainty about the viral loads of infectious individuals required to transmit COVID-19 via aerosol. In addition, there is a lack of both quantification of the influencing parameters on airborne transmission and simple-to-use models for assessing the risk of infection in practice, which furthermore quantify the influence of non-medical preventive measures. In this study, a dose-response model was adopted to analyze 25 documented outbreaks at infection rates of 4-100%. We show that infection was only possible if the viral load was higher than 108 viral copies/mL. Based on mathematical simplifications of our approach to predict the probable situational attack rate (PARs) of a group of persons in a room, and valid assumptions, we provide simplified equations to calculate, among others, the maximum possible number of persons and the person-related virus-free air supply flow necessary to keep the number of newly infected persons to less than one. A comparison of different preventive measures revealed that testing contributes the most to the joint protective effect, besides wearing masks and increasing ventilation. In addition, we conclude that absolute volume flow rate or person-related volume flow rate are more intuitive parameters for evaluating ventilation for infection prevention than air exchange rate.
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Affiliation(s)
- Martin Kriegel
- Hermann-Rietschel-Institut, Technical University of Berlin, 10623 Berlin, Germany;
| | - Anne Hartmann
- Hermann-Rietschel-Institut, Technical University of Berlin, 10623 Berlin, Germany;
| | - Udo Buchholz
- Department for Infectious Disease Epidemiology, Robert Koch Institute, 13353 Berlin, Germany; (U.B.); (J.S.)
| | - Janna Seifried
- Department for Infectious Disease Epidemiology, Robert Koch Institute, 13353 Berlin, Germany; (U.B.); (J.S.)
| | | | - Petra Gastmeier
- Institute for Hygiene and Environmental Medicine, Charité-University Medicine Berlin, 12203 Berlin, Germany;
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Narayanan SR, Yang S. Airborne transmission of virus-laden aerosols inside a music classroom: Effects of portable purifiers and aerosol injection rates. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2021; 33:033307. [PMID: 33746493 PMCID: PMC7978150 DOI: 10.1063/5.0042474] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 01/18/2021] [Indexed: 05/04/2023]
Abstract
The ongoing COVID-19 pandemic has shifted attention to the airborne transmission of exhaled droplet nuclei within indoor environments. The spread of aerosols through singing and musical instruments in music performances has necessitated precautionary methods such as masks and portable purifiers. This study investigates the effects of placing portable air purifiers at different locations inside a classroom and the effects of different aerosol injection rates (e.g., with and without masks, different musical instruments, and different injection modes). Aerosol deposition, airborne concentration, and removal are analyzed in this study. It was found that using purifiers could help in achieving ventilation rates close to the prescribed values by the World Health Organization, while also achieving aerosol removal times within the Center of Disease Control and Prevention recommended guidelines. This could help in deciding break periods between classroom sessions, which was around 25 min through this study. Moreover, proper placement of purifiers could offer significant advantages in reducing airborne aerosol numbers (offering several orders of magnitude higher aerosol removal when compared to nearly zero removal when having no purifiers), and improper placement of the purifiers could worsen the situation. This study suggests the purifier to be placed close to the injector to yield a benefit and away from the people to be protected. The injection rate was found to have an almost linear correlation with the average airborne aerosol suspension rate and deposition rate, which could be used to predict the trends for scenarios with other injection rates.
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Affiliation(s)
- Sai Ranjeet Narayanan
- Department of Mechanical Engineering, University of Minnesota–Twin
Cities, Minneapolis, Minnesota 55455, USA
| | - Suo Yang
- Department of Mechanical Engineering, University of Minnesota–Twin
Cities, Minneapolis, Minnesota 55455, USA
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Mürbe D, Kriegel M, Lange J, Schumann L, Hartmann A, Fleischer M. Aerosol emission of adolescents voices during speaking, singing and shouting. PLoS One 2021; 16:e0246819. [PMID: 33566852 PMCID: PMC7875408 DOI: 10.1371/journal.pone.0246819] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 01/26/2021] [Indexed: 01/29/2023] Open
Abstract
Since the outbreak of the COVID-19 pandemic, singing activities for children and young people have been strictly regulated with far-reaching consequences for music education in schools and ensemble and choir singing in some places. This is also due to the fact, that there has been no reliable data available on aerosol emissions from adolescents speaking, singing, and shouting. By utilizing a laser particle counter in cleanroom conditions we show, that adolescents emit fewer aerosol particles during singing than what has been known so far for adults. In our data, the emission rates ranged from 16 P/s to 267 P/s for speaking, 141 P/s to 1240 P/s for singing, and 683 P/s to 4332 P/s for shouting. The data advocate an adaptation of existing risk management strategies and rules of conduct for groups of singing adolescents, like gatherings in an educational context, e.g. singing lessons or choir rehearsals.
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Affiliation(s)
- Dirk Mürbe
- Department of Audiology and Phoniatrics, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Martin Kriegel
- Hermann-Rietschel-Institut, Technische Universität Berlin, Berlin, Germany
| | - Julia Lange
- Hermann-Rietschel-Institut, Technische Universität Berlin, Berlin, Germany
| | - Lukas Schumann
- Hermann-Rietschel-Institut, Technische Universität Berlin, Berlin, Germany
| | - Anne Hartmann
- Hermann-Rietschel-Institut, Technische Universität Berlin, Berlin, Germany
| | - Mario Fleischer
- Department of Audiology and Phoniatrics, Charité – Universitätsmedizin Berlin, Berlin, Germany
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