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Enright C, Gilbourne C, Kiersey R, Parlour R, Flanagan P, McGowan E, Boland M, Mulholland D. Efficacy of facemasks in preventing transmission of COVID-19 in non-healthcare settings: A scoping review. J Infect Prev 2024; 25:24-32. [PMID: 38362115 PMCID: PMC10866118 DOI: 10.1177/17571774231203387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 08/14/2023] [Indexed: 02/17/2024] Open
Abstract
Background During the COVID-19 pandemic, an abundance of literature relating to the efficacy of face masks on reducing transmission of COVID-19 in non-healthcare settings emerged. Aim/objective The aim of this scoping review was to allow the identification of: types of evidence conducted in this area; knowledge gaps and common concepts relating to mask efficacy in non-healthcare settings. Methods A comprehensive literature search was conducted in PubMed, CINAHL, MEDLINE, Embase and the Irish Management Institute bibliographic database on December 15th, 2021. All types of face masks were included. Of 722 records, 16 were included after full text screening. Findings/results Themes from an adapted model of Howard et al. framework were used to group results and identify common concepts. The grouped thematic results were then applied to the socio-ecological model. This illustrated the multifactorial elements determining the efficacy of masks themselves while also illustrating how other factors such as individual behaviours, social interactions, settings and national policy can influence the degree of the protective effect. Discussion The findings from this scoping review indicate that an abundance of experimental literature is available indicating that masks are effective at preventing COVID-19 transmission but their degree of efficacy is impacted by external factors. This review highlights that the quality of the evidence available is low.
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Cimini A, Borgioni A, Passarini E, Mancini C, Proietti A, Buccini L, Stornelli E, Schifano E, Dinarelli S, Mura F, Sergi C, Bavasso I, Cortese B, Passeri D, Imperi E, Rinaldi T, Picano A, Rossi M. Upscaling of Electrospinning Technology and the Application of Functionalized PVDF-HFP@TiO 2 Electrospun Nanofibers for the Rapid Photocatalytic Deactivation of Bacteria on Advanced Face Masks. Polymers (Basel) 2023; 15:4586. [PMID: 38231986 PMCID: PMC10708761 DOI: 10.3390/polym15234586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 11/25/2023] [Accepted: 11/28/2023] [Indexed: 01/19/2024] Open
Abstract
In recent years, Electrospinning (ES) has been revealed to be a straightforward and innovative approach to manufacture functionalized nanofiber-based membranes with high filtering performance against fine Particulate Matter (PM) and proper bioactive properties. These qualities are useful for tackling current issues from bacterial contamination on Personal Protective Equipment (PPE) surfaces to the reusability of both disposable single-use face masks and respirator filters. Despite the fact that the conventional ES process can be upscaled to promote a high-rate nanofiber production, the number of research works on the design of hybrid materials embedded in electrospun membranes for face mask application is still low and has mainly been carried out at the laboratory scale. In this work, a multi-needle ES was employed in a continuous processing for the manufacturing of both pristine Poly (Vinylidene Fluoride-co-Hexafluoropropylene) (PVDF-HFP) nanofibers and functionalized membrane ones embedded with TiO2 Nanoparticles (NPs) (PVDF-HFP@TiO2). The nanofibers were collected on Polyethylene Terephthalate (PET) nonwoven spunbond fabric and characterized by using Scanning Electron Microscopy and Energy Dispersive X-ray (SEM-EDX), Raman spectroscopy, and Atomic Force Microscopy (AFM) analysis. The photocatalytic study performed on the electrospun membranes proved that the PVDF-HFP@TiO2 nanofibers provide a significant antibacterial activity for both Staphylococcus aureus (~94%) and Pseudomonas aeruginosa (~85%), after only 5 min of exposure to a UV-A light source. In addition, the PVDF-HFP@TiO2 nanofibers exhibit high filtration efficiency against submicron particles (~99%) and a low pressure drop (~3 mbar), in accordance with the standard required for Filtering Face Piece masks (FFPs). Therefore, these results aim to provide a real perspective on producing electrospun polymer-based nanotextiles with self-sterilizing properties for the implementation of advanced face masks on a large scale.
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Affiliation(s)
- Adriano Cimini
- Department of Basic and Applied Sciences for Engineering, Sapienza University of Rome, Via A. Scarpa 16, 00161 Rome, Italy (A.P.); (L.B.); (E.S.); (D.P.)
- Industrial Research Laboratory, LABOR s.r.l., Via Giacomo Peroni 386, 00131 Rome, Italy
| | - Alessia Borgioni
- Department of Biology and Biotechnologies, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (A.B.); (E.P.)
| | - Elena Passarini
- Department of Biology and Biotechnologies, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (A.B.); (E.P.)
| | - Chiara Mancini
- Department of Basic and Applied Sciences for Engineering, Sapienza University of Rome, Via A. Scarpa 16, 00161 Rome, Italy (A.P.); (L.B.); (E.S.); (D.P.)
| | - Anacleto Proietti
- Department of Basic and Applied Sciences for Engineering, Sapienza University of Rome, Via A. Scarpa 16, 00161 Rome, Italy (A.P.); (L.B.); (E.S.); (D.P.)
| | - Luca Buccini
- Department of Basic and Applied Sciences for Engineering, Sapienza University of Rome, Via A. Scarpa 16, 00161 Rome, Italy (A.P.); (L.B.); (E.S.); (D.P.)
| | - Eleonora Stornelli
- Department of Basic and Applied Sciences for Engineering, Sapienza University of Rome, Via A. Scarpa 16, 00161 Rome, Italy (A.P.); (L.B.); (E.S.); (D.P.)
| | - Emily Schifano
- Department of Biology and Biotechnologies, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (A.B.); (E.P.)
| | - Simone Dinarelli
- Institute for the Structure of Matter (ISM), National Research Council (CNR), Via del Fosso del Cavaliere 100, 00133 Rome, Italy;
| | - Francesco Mura
- Department of Basic and Applied Sciences for Engineering, Sapienza University of Rome, Via A. Scarpa 16, 00161 Rome, Italy (A.P.); (L.B.); (E.S.); (D.P.)
- Research Center for Nanotechnology for Engineering of Sapienza (CNIS), Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Claudia Sergi
- Department of Chemical Engineering Materials Environment, Sapienza University of Rome & UdR INSTM, Via Eudossiana 18, 00184 Rome, Italy
| | - Irene Bavasso
- Department of Chemical Engineering Materials Environment, Sapienza University of Rome & UdR INSTM, Via Eudossiana 18, 00184 Rome, Italy
| | - Barbara Cortese
- National Research Council (CNR), Institute of Nanotechnology (CNR Nanotec), c/o Edificio Fermi, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy;
| | - Daniele Passeri
- Department of Basic and Applied Sciences for Engineering, Sapienza University of Rome, Via A. Scarpa 16, 00161 Rome, Italy (A.P.); (L.B.); (E.S.); (D.P.)
- Research Center for Nanotechnology for Engineering of Sapienza (CNIS), Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Enrico Imperi
- Industrial Research Laboratory, LABOR s.r.l., Via Giacomo Peroni 386, 00131 Rome, Italy
| | - Teresa Rinaldi
- Department of Biology and Biotechnologies, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (A.B.); (E.P.)
| | - Alfredo Picano
- National Research Council of Italy, Institute for Microelectronics and Microsystems (CNR-IMM), Via Piero Gobetti 101, 40129 Bologna, Italy
| | - Marco Rossi
- Department of Basic and Applied Sciences for Engineering, Sapienza University of Rome, Via A. Scarpa 16, 00161 Rome, Italy (A.P.); (L.B.); (E.S.); (D.P.)
- Research Center for Nanotechnology for Engineering of Sapienza (CNIS), Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
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3
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Cimini A, Imperi E, Picano A, Rossi M. Electrospun nanofibers for medical face mask with protection capabilities against viruses: State of the art and perspective for industrial scale-up. Appl Mater Today 2023; 32:101833. [PMID: 37152683 PMCID: PMC10151159 DOI: 10.1016/j.apmt.2023.101833] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 04/13/2023] [Accepted: 04/25/2023] [Indexed: 05/09/2023]
Abstract
Face masks have proven to be a useful protection from airborne viruses and bacteria, especially in the recent years pandemic outbreak when they effectively lowered the risk of infection from Coronavirus disease (COVID-19) or Omicron variants, being recognized as one of the main protective measures adopted by the World Health Organization (WHO). The need for improving the filtering efficiency performance to prevent penetration of fine particulate matter (PM), which can be potential bacteria or virus carriers, has led the research into developing new methods and techniques for face mask fabrication. In this perspective, Electrospinning has shown to be the most efficient technique to get either synthetic or natural polymers-based fibers with size down to the nanoscale providing remarkable performance in terms of both particle filtration and breathability. The aim of this Review is to give further insight into the implementation of electrospun nanofibers for the realization of the next generation of face masks, with functionalized membranes via addiction of active material to the polymer solutions that can give optimal features about antibacterial, antiviral, self-sterilization, and electrical energy storage capabilities. Furthermore, the recent advances regarding the use of renewable materials and green solvent strategies to improve the sustainability of electrospun membranes and to fabricate eco-friendly filters are here discussed, especially in view of the large-scale nanofiber production where traditional membrane manufacturing may result in a high environmental and health risk.
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Affiliation(s)
- A Cimini
- Department of Basic and Applied Sciences for Engineering, University of Rome Sapienza, Rome 00161, Italy
- LABOR s.r.l., Industrial Research Laboratory, Via Giacomo Peroni, 386, Rome, Italy
| | - E Imperi
- LABOR s.r.l., Industrial Research Laboratory, Via Giacomo Peroni, 386, Rome, Italy
| | - A Picano
- LABOR s.r.l., Industrial Research Laboratory, Via Giacomo Peroni, 386, Rome, Italy
| | - M Rossi
- Department of Basic and Applied Sciences for Engineering, University of Rome Sapienza, Rome 00161, Italy
- Research Center for Nanotechnology for Engineering of Sapienza (CNIS), University of Rome Sapienza, Rome 00185, Italy
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Peng Y, Yao M. Quantitatively Visualizing Airborne Disease Transmission Risks of Different Exhalation Activities through CO 2 Imaging. Environ Sci Technol 2023; 57:6865-6875. [PMID: 37074044 PMCID: PMC10124748 DOI: 10.1021/acs.est.2c08503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 03/23/2023] [Accepted: 04/03/2023] [Indexed: 05/03/2023]
Abstract
Aerosol transmission has played a leading role in COVID-19 pandemic. However, there is still a poor understanding about how it is transmitted. This work was designed to study the exhaled breath flow dynamics and transmission risks under different exhaling modes. Using an infrared photography device, exhaled flow characteristics of different breathing activities, such as deep breathing, dry coughing, and laughing, together with the roles of mouth and nose were characterized by imaging CO2 flow morphologies. Both mouth and nose played an important role in the disease transmission though in the downward direction for the nose. In contrast to the trajectory commonly modeled, the exhaled airflows appeared with turbulent entrainments and obvious irregular movements, particularly the exhalations involving mouth were directed horizontal and had a higher propagation capacity and transmission risk. While the cumulative risk was high for deep breathing, those transient ones from dry coughing, yawning, and laughing were also shown to be significant. Various protective measures including masks, canteen table shields, and wearable devices were visually demonstrated to be effective for altering the exhaled flow directions. This work is useful to understanding the risk of aerosol infection and guiding the formulation of its prevention and control strategies. Experimental data also provide important information for refining model boundary conditions.
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Affiliation(s)
- Yijiao Peng
- State Key Joint Laboratory of Environmental Simulation and
Pollution Control, College of Environmental Sciences and Engineering, Peking
University, Beijing 100871, China
| | - Maosheng Yao
- State Key Joint Laboratory of Environmental Simulation and
Pollution Control, College of Environmental Sciences and Engineering, Peking
University, Beijing 100871, China
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Noh JW, Lee WR, Kim LH, Cheon J, Kwon YD, Yoo KB. Influence of COVID-19-Related Interventions on the Number of Inpatients with Acute Viral Respiratory Infections: Using Interrupted Time Series Analysis. Int J Environ Res Public Health 2023; 20:2808. [PMID: 36833505 PMCID: PMC9956170 DOI: 10.3390/ijerph20042808] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 01/29/2023] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
After the first COVID-19 patient was diagnosed, non-pharmaceutical interventions such as social distancing and behavior change campaigns were implemented in South Korea. The social distancing policy restricted unnecessary gatherings and activities to prevent local transmission. This study aims to evaluate the effect of social distancing, a strategy for COVID-19 prevention, on the number of acute respiratory infection inpatients. This study used the number of hospitalized patients with acute respiratory infection from the Infectious Disease Portal of the Korea Centers for Disease Control and Prevention (KCDC) between the first week of January 2018, to the last week of January 2021. Intervention 1t represents the first patient occurrence of COVID-19, Intervention 2t represents the relaxing of the social distancing policy. We used acute respiratory infection statistics from Korea and segmented regression analysis was used. The analysis showed that the trend of the number of acute respiratory infection inpatients decreased after the implementation of the first patient incidence of COVID-19 due to prevention activities. After the relaxing of the social distancing policy, the number of inpatients with acute respiratory infections significantly increased. This study verified the effect of social distancing on the reduction in hospital admissions for acute respiratory viral infections.
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Affiliation(s)
- Jin-Won Noh
- Division of Health Administration, College of Software and Digital Healthcare Convergence, Yonsei University, Wonju 26493, Republic of Korea
- Department of Health Administration, Graduate School, Yonsei University, Wonju 26493, Republic of Korea
| | - Woo-Ri Lee
- Division of Cancer Control & Policy, National Cancer Control Institute, National Cancer Center, Goyang 10408, Republic of Korea
| | - Li-Hyun Kim
- Department of Healthcare Institution Support, National Health Insurance Service, Wonju 26464, Republic of Korea
| | - Jooyoung Cheon
- Department of Nursing Science, Sungshin Women’s University, Seoul 02844, Republic of Korea
| | - Young Dae Kwon
- Department of Humanities and Social Medicine, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Catholic Institute for Healthcare Management, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Ki-Bong Yoo
- Division of Health Administration, College of Software and Digital Healthcare Convergence, Yonsei University, Wonju 26493, Republic of Korea
- Department of Health Administration, Graduate School, Yonsei University, Wonju 26493, Republic of Korea
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Kniesburges S, Schlegel P, Peters G, Westphalen C, Jakubaß B, Veltrup R, Kist AM, Döllinger M, Gantner S, Kuranova L, Benthaus T, Semmler M, Echternach M. Effects of surgical masks on aerosol dispersion in professional singing. J Expo Sci Environ Epidemiol 2022; 32:727-734. [PMID: 34611302 PMCID: PMC8491963 DOI: 10.1038/s41370-021-00385-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 09/09/2021] [Accepted: 09/10/2021] [Indexed: 05/02/2023]
Abstract
BACKGROUND In the CoVID-19 pandemic, singing came into focus as a high-risk activity for the infection with airborne viruses and was therefore forbidden by many governmental administrations. OBJECTIVE The aim of this study is to investigate the effectiveness of surgical masks regarding the spatial and temporal dispersion of aerosol and droplets during professional singing. METHODS Ten professional singers performed a passage of the Ludwig van Beethoven's "Ode of Joy" in two experimental setups-each with and without surgical masks. First, they sang with previously inhaled vapor of e-cigarettes. The emitted cloud was recorded by three cameras to measure its dispersion dynamics. Secondly, the naturally expelled larger droplets were illuminated by a laser light sheet and recorded by a high-speed camera. RESULTS The exhaled vapor aerosols were decelerated and deflected by the mask and stayed in the singer's near-field around and above their heads. In contrast, without mask, the aerosols spread widely reaching distances up to 1.3 m. The larger droplets were reduced by up to 86% with a surgical mask worn. SIGNIFICANCE The study shows that surgical masks display an effective tool to reduce the range of aerosol dispersion during singing. In combination with an appropriate aeration strategy for aerosol removal, choir singers could be positioned in a more compact assembly without contaminating neighboring singers all singers.
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Affiliation(s)
- Stefan Kniesburges
- Division of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany.
| | - Patrick Schlegel
- Department of Head and Neck Surgery, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, USA
| | - Gregor Peters
- Division of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Caroline Westphalen
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, University Hospital, LMU Munich, Munich, Germany
| | - Bernhard Jakubaß
- Division of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Reinhard Veltrup
- Division of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Andreas M Kist
- Department of Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Michael Döllinger
- Division of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Sophia Gantner
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, University Hospital, LMU Munich, Munich, Germany
| | - Liudmila Kuranova
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, University Hospital, LMU Munich, Munich, Germany
| | - Tobias Benthaus
- Institute and Clinic for Occupational, Social and Environmental Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Marion Semmler
- Division of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Matthias Echternach
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, University Hospital, LMU Munich, Munich, Germany
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Dallner M, Harlow J, Nasheri N. Efficacy of washing produce in removing human coronavirus OC43 and murine norovirus. J Appl Microbiol 2022; 133:1800-1807. [PMID: 35702940 PMCID: PMC9545982 DOI: 10.1111/jam.15667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/07/2022] [Accepted: 06/11/2022] [Indexed: 11/27/2022]
Abstract
AIMS Fresh produce is often a vehicle for the transmission of foodborne pathogens such as human norovirus. Thus, it is recommended to wash the surface of produce before consumption, and one of the most common ways to wash produce is by rinsing under running tap water. This study determined the effectiveness of removal of human coronavirus-OC43 (HCoV-OC43), as a surrogate for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and murine norovirus-1 (MNV-1), as a surrogate for human norovirus, from contaminated lettuce, apples and cucumbers. METHODS AND RESULTS The produce surfaces were artificially inoculated in conjunction with faecal material to represent natural contamination. Rinsing under tap water for 10 s at 40 ml/s removed 1.94 ± 0.44, 1.42 ± 0.00 and 1.42 ± 0.42 log of HCoV-OC43 from apple, cucumber and lettuce respectively. The same washing technique removed 1.77 ± 0.17, 1.42 ± 0.07 and 1.79 ± 0.14 log of MNV-1 from apple, cucumber and lettuce respectively. This washing technique was effective at reducing a significant amount of viral contamination, however, it was not enough to eliminate the entire contamination. There was no significant difference in the reduction of viral load between the two viruses, nor between the three surfaces tested in this study. CONCLUSIONS Our data suggest that washing under tap water would be an efficient way of reducing the risk of foodborne viral transmission only if the level of contamination is less than 2 log PFU. SIGNIFICANCE AND IMPACT OF STUDY This study demonstrates that running tap water was effective at reducing the amount of infectious HCoV-OC43 and MNV on produce surfaces, and washing produce continues to be an important task to perform prior to consumption to avoid infection by foodborne viruses, particularly for foods which are eaten raw.
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Affiliation(s)
- Matthew Dallner
- National Food Virology Reference CentreBureau of Microbial Hazards, Health CanadaOttawaOntarioCanada
| | - Jennifer Harlow
- National Food Virology Reference CentreBureau of Microbial Hazards, Health CanadaOttawaOntarioCanada
| | - Neda Nasheri
- National Food Virology Reference CentreBureau of Microbial Hazards, Health CanadaOttawaOntarioCanada
- Department of BiochemistryMicrobiology and Immunology, Faculty of Medicine, University of OttawaOttawaOntarioCanada
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Oswin HP, Haddrell AE, Otero-Fernandez M, Mann JFS, Cogan TA, Hilditch TG, Tian J, Hardy DA, Hill DJ, Finn A, Davidson AD, Reid JP. The dynamics of SARS-CoV-2 infectivity with changes in aerosol microenvironment. Proc Natl Acad Sci U S A 2022; 119:e2200109119. [PMID: 35763573 PMCID: PMC9271203 DOI: 10.1073/pnas.2200109119] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Understanding the factors that influence the airborne survival of viruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in aerosols is important for identifying routes of transmission and the value of various mitigation strategies for preventing transmission. We present measurements of the stability of SARS-CoV-2 in aerosol droplets (∼5 to 10 µm equilibrated radius) over timescales spanning 5 s to 20 min using an instrument to probe survival in a small population of droplets (typically 5 to 10) containing ∼1 virus/droplet. Measurements of airborne infectivity change are coupled with a detailed physicochemical analysis of the airborne droplets containing the virus. A decrease in infectivity to ∼10% of the starting value was observable for SARS-CoV-2 over 20 min, with a large proportion of the loss occurring within the first 5 min after aerosolization. The initial rate of infectivity loss was found to correlate with physical transformation of the equilibrating droplet; salts within the droplets crystallize at relative humidities (RHs) below 50%, leading to a near-instant loss of infectivity in 50 to 60% of the virus. However, at 90% RH, the droplet remains homogenous and aqueous, and the viral stability is sustained for the first 2 min, beyond which it decays to only 10% remaining infectious after 10 min. The loss of infectivity at high RH is consistent with an elevation in the pH of the droplets, caused by volatilization of CO2 from bicarbonate buffer within the droplet. Four different variants of SARS-CoV-2 were compared and found to have a similar degree of airborne stability at both high and low RH.
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Affiliation(s)
- Henry P. Oswin
- aSchool of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Allen E. Haddrell
- aSchool of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
- 1To whom correspondence may be addressed. , , or
| | - Mara Otero-Fernandez
- aSchool of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Jamie F. S. Mann
- bBristol Veterinary School, University of Bristol, Langford, Bristol BS40 5DU, United Kingdom
| | - Tristan A. Cogan
- bBristol Veterinary School, University of Bristol, Langford, Bristol BS40 5DU, United Kingdom
| | - Thomas G. Hilditch
- aSchool of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Jianghan Tian
- aSchool of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Daniel A. Hardy
- aSchool of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Darryl J. Hill
- cSchool of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Adam Finn
- cSchool of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Andrew D. Davidson
- cSchool of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TS, United Kingdom
- 1To whom correspondence may be addressed. , , or
| | - Jonathan P. Reid
- aSchool of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
- 1To whom correspondence may be addressed. , , or
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Wang Q, Gu J, An T. The emission and dynamics of droplets from human expiratory activities and COVID-19 transmission in public transport system: A review. Build Environ 2022; 219:109224. [PMID: 35645454 PMCID: PMC9126829 DOI: 10.1016/j.buildenv.2022.109224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 05/03/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
The public transport system, containing a large number of passengers in enclosed and confined spaces, provides suitable conditions for the spread of respiratory diseases. Understanding how diseases are transmitted in public transport environment is of vital importance to public health. However, this is a highly multidisciplinary matter and the related physical processes including the emissions of respiratory droplets, the droplet dynamics and transport pathways, and subsequently, the infection risk in public transport, are poorly understood. To better grasp the complex processes involved, a synthesis of current knowledge is required. Therefore, we conducted a review on the behaviors of respiratory droplets in public transport system, covering a wide scope from the emission profiles of expiratory droplets, the droplet dynamics and transport, to the transmission of COVID-19 in public transport. The literature was searched using related keywords in Web of Science and PubMed and screened for suitability. The droplet size is a key parameter in determining the deposition and evaporation, which together with the exhaled air velocity largely determines the horizontal travel distance. The potential transmission route and transmission rate in public transport as well as the factors influencing the virus-laden droplet behaviors and virus viability (such as ventilation system, wearing personal protective equipment, air temperature and relative humidity) were also discussed. The review also suggests that future studies should address the uncertainties in droplet emission profiles associated with the measurement techniques, and preferably build a database based on a unified testing protocol. Further investigations based on field measurements and modeling studies into the influence of different ventilation systems on the transmission rate in public transport are also needed, which would provide scientific basis for controlling the transmission of diseases.
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Affiliation(s)
- Qiaoqiao Wang
- Institute for Environmental and Climate Research, Jinan University, 511443, Guangzhou, China
- Guangdong-Hong Kong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, 511443, Guangzhou, China
| | - Jianwei Gu
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, 510006, Guangzhou, China
- Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, School of Environmental Science and Engineering, Guangdong University of Technology, 510006, Guangzhou, China
| | - Taicheng An
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, 510006, Guangzhou, China
- Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, School of Environmental Science and Engineering, Guangdong University of Technology, 510006, Guangzhou, China
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10
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Veltrup R, Kniesburges S, Döllinger M, Falk S, Mueller SK. Evaluation of Respiratory Particle Emission during Otorhinolaryngological Procedures in the Context of the SARS-CoV-2 Pandemic. Diagnostics (Basel) 2022; 12:diagnostics12071603. [PMID: 35885507 PMCID: PMC9315468 DOI: 10.3390/diagnostics12071603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/26/2022] [Accepted: 06/29/2022] [Indexed: 11/29/2022] Open
Abstract
Understanding the risk of infection by routine medical examination is important for the protection of the medical personnel. In this study we investigated respiratory particles emitted by patients during routine otolaryngologic procedures and assessed the risks for the performing physician. We developed two experimental setups to measure aerosol and droplet emission during rigid/flexible laryngoscopy, rhinoscopy, pharyngoscopy, otoscopy, sonography and patient interview for subjects with and without masks. A high-speed-camera setup was used to detect ballistic droplets (approx. > 100 µm) and an aerosol-particle-sizer was used to detect aerosol particles in the range of 0.3 µm to 10 µm. Aerosol particle counts were highly increased for coughing and slightly increased for heavy breathing in subjects without masks. The highest aerosol particle counts occurred during rigid laryngoscopy. During laryngoscopy and rhinoscopy, the examiner was exposed to increased particle emission due to close proximity to the patient’s face and provoked events such as coughing. However, even during sonography or otoscopy without a mask, aerosol particles were expelled close to the examiner. The physician’s exposure to respiratory particles can be reduced by deliberate choice of examination technique depending on medical indication and the use of appropriate equipment for the examiners and the patients (e.g., FFP2 masks for both).
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11
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Reiss RA, Makhnin O, Lowe TC. Rapid Method to Quantify the Antiviral Potential of Porous and Nonporous Material Using the Enveloped Bacteriophage Phi6. Environ Sci Technol 2022; 56:8350-8362. [PMID: 35543429 DOI: 10.1021/acs.est.1c07716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The pandemic revealed significant gaps in our understanding of the antiviral potential of porous textiles used for personal protective equipment and nonporous touch surfaces. What is the fate of a microbe when it encounters an abiotic surface? How can we change the microenvironment of materials to improve antimicrobial properties? Filling these gaps requires increasing data generation throughput. A method to accomplish this leverages the use of the enveloped bacteriophage ϕ6, an adjustable spacing multichannel pipette, and the statistical design opportunities inherent in the ordered array of the 24-well culture plate format, resulting in a semi-automated small drop assay. For 100 mm2 nonporous coupons of Cu and Zn, the reduction in ϕ6 infectivity fits first-order kinetics, resulting in half-lives (T50) of 4.2 ± 0.1 and 29.4 ± 1.6 min, respectively. In contrast, exposure to stainless steel has no significant effect on infectivity. For porous textiles, differences associated with composition, color, and surface treatment of samples are detected within 5 min of exposure. Half-lives for differently dyed Zn-containing fabrics from commercially available masks ranged from 2.1 ± 0.05 to 9.4 ± 0.2 min. A path toward full automation and the application of machine learning techniques to guide combinatorial material engineering is presented.
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Affiliation(s)
- Rebecca A Reiss
- Biology Department, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, New Mexico 87801-4750, United States
| | - Oleg Makhnin
- Mathematics Department, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, New Mexico 87801-4750, United States
| | - Terry C Lowe
- Department of Metallurgical & Materials Engineering, Colorado School of Mines, 920 15th, Street, Golden, Colorado 80401-1887, United States
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12
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Zhang C, Nielsen PV, Liu L, Sigmer ET, Mikkelsen SG, Jensen RL. The source control effect of personal protection equipment and physical barrier on short-range airborne transmission. Build Environ 2022; 211:108751. [PMID: 35002048 PMCID: PMC8721933 DOI: 10.1016/j.buildenv.2022.108751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/09/2021] [Accepted: 01/01/2022] [Indexed: 05/22/2023]
Abstract
In order to control the spread of Covid-19, authorities provide various prevention guidelines and recommendations for health workers and the public. Personal protection equipment (PPE) and physical barrier are the most widely applied prevention measures in practice due to their affordability and ease of implementation. This study aims to investigate the effect of PPE and physical barriers on mitigating the short-range airborne transmission between two people in a ventilated environment. Four types of PPE (surgical mask, two types of face shield, and mouth visor), and two different sizes of the physical barrier were tested in a controlled environment with two life-size breathing thermal manikins. The PPE was worn by the source manikin to test the efficiency of source control. The measurement results revealed that the principles of PPE on preventing short-range droplet and airborne transmission are different. Instead of filtering the fine droplet nuclei, they mainly redirect the virus-laden exhalation jet and avoid the exhaled flow entering the target's inhalation region. Physical barriers can block the spreading of droplet nuclei and create a good micro environment at short distances between persons. However, special attention should be paid to arranging the physical barrier and operating the ventilation system to avoid the stagnant zone where the contaminant accumulates.
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Affiliation(s)
- Chen Zhang
- Department of the Built Environment, Aalborg University, Aalborg, 9220, Denmark
| | - Peter V Nielsen
- Department of the Built Environment, Aalborg University, Aalborg, 9220, Denmark
| | - Li Liu
- Department of Building Science, School of Architecture, Tsinghua University, Beijing, 100084, China
| | | | | | - Rasmus L Jensen
- Department of the Built Environment, Aalborg University, Aalborg, 9220, Denmark
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13
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Deng Z, Chen Q. What is suitable social distancing for people wearing face masks during the COVID-19 pandemic? Indoor Air 2022; 32:e12935. [PMID: 34605574 PMCID: PMC8652892 DOI: 10.1111/ina.12935] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/05/2021] [Accepted: 09/18/2021] [Indexed: 05/06/2023]
Abstract
COVID-19 has caused the global pandemic and had a serious impact on people's daily lives. The respiratory droplets produced from coughing and talking of an infected patient were possible transmission routes of coronavirus between people. To avoid the infection, the US Centers for Disease Control and Prevention (CDC) advised to wear face masks while maintaining a social distancing of 2 m. Can the social distancing be reduced if people wear masks? To answer this question, we measured the mass of inhaled droplets by a susceptible manikin wearing a mask with different social distances, which was produced by coughing and talking of an index "patient" (human subject) also wearing a mask. We also used the computational fluid dynamics (CFD) technology with a porous media model and particle dispersion model to simulate the transmission of droplets from the patient to the susceptible person with surgical and N95 masks. We compared the CFD results with the measured velocity in the environmental chamber and found that the social distancing could be reduced to 0.5 m when people wearing face masks. In this case, the mass concentration of inhaled particles was less than two people without wearing masks and with a social distancing of 2 m. Hence, when the social distancing was difficult, wearing masks could protect people. We also found that the leakage between the face mask and the human face played an important role in the exhaled airflow pattern and particle dispersion. The verified numerical model can be used for more scenarios with different indoor environments and HVAC systems. The results of this study would make business profitable with reduced social distancing in transportation, education, and entertainment industries, which was beneficial for the reopening of the economy.
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Affiliation(s)
- Zhipeng Deng
- School of Mechanical EngineeringPurdue UniversityWest LafayetteINUSA
| | - Qingyan Chen
- Department of Building Environment and Energy EngineeringThe Hong Kong Polytechnic UniversityKowloonHong Kong
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14
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Acuti Martellucci C, Flacco ME, Martellucci M, Violante FS, Manzoli L. Inhaled CO 2 Concentration While Wearing Face Masks: A Pilot Study Using Capnography. Environ Health Insights 2022. [PMID: 36133777 DOI: 10.1101/2022.05.10.22274813] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
BACKGROUND Face masks are recommended based on the assumption that they protect against SARS-CoV-2 transmission, however studies on their potential side effects are still lacking. We aimed to evaluate the inhaled air carbon dioxide (CO2) concentration, when wearing masks. METHODS We measured end-tidal CO2 using professional side-stream capnography, with water-removing tubing, (1) without masks, (2) wearing a surgical mask, and (3) wearing a FFP2 respirator (for 5 minutes each while seated after 10 minutes of rest), in 146 healthy volunteers aged 10 to 90 years, from the general population of Ferrara, Italy. The inhaled air CO2 concentration was computed as: ([mask volume × end-tidal CO2] + [tidal volume - mask volume] × ambient air CO2)/tidal volume. RESULTS With surgical masks, the mean CO2 concentration was 7091 ± 2491 ppm in children, 4835 ± 869 in adults, and 4379 ± 978 in the elderly. With FFP2 respirators, this concentration was 13 665 ± 3655 in children, 8502 ± 1859 in adults, and 9027 ± 1882 in the elderly. The proportion showing a CO2 concentration higher than the 5000 ppm (8-hour average) acceptable threshold for workers was 41.1% with surgical masks, and 99.3% with FFP2 respirators. Adjusting for age, gender, BMI, and smoking, the inhaled air CO2 concentration significantly increased with increasing respiratory rate (mean 10 837 ±3712 ppm among participants ⩾18 breaths/minute, with FFP2 respirators), and among the minors. CONCLUSION If these results are confirmed, the current guidelines on mask-wearing should be reevaluated.
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Affiliation(s)
| | - Maria Elena Flacco
- Department of Environmental and Prevention Sciences, University of Ferrara, Ferrara, Italy
| | - Mosè Martellucci
- Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Francesco Saverio Violante
- Occupational Health Unit, Sant'Orsola Malpighi University Hospital, University of Bologna, Bologna, Italy
| | - Lamberto Manzoli
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
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15
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Stanislas TT, Bilba K, de Oliveira Santos RP, Onésippe-Potiron C, Savastano Junior H, Arsène MA. Nanocellulose-based membrane as a potential material for high performance biodegradable aerosol respirators for SARS-CoV-2 prevention: a review. Cellulose (Lond) 2022; 29:8001-8024. [PMID: 35990792 PMCID: PMC9383689 DOI: 10.1007/s10570-022-04792-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 08/02/2022] [Indexed: 05/14/2023]
Abstract
The controversy surrounding the transmission of COVID-19 in 2020 has revealed the need to better understand the airborne transmission route of respiratory viruses to establish appropriate strategies to limit their transmission. The effectiveness in protecting against COVID-19 has led to a high demand for face masks. This includes the single-use of non-degradable masks and Filtering Facepiece Respirators by a large proportion of the public, leading to environmental concerns related to waste management. Thus, nanocellulose-based membranes are a promising environmental solution for aerosol filtration due to their biodegradability, renewability, biocompatibility, high specific surface area, non-toxicity, ease of functionalization and worldwide availability. Although the technology for producing high-performance aerosol filter membranes from cellulose-based materials is still in its initial stage, several promising results show the prospects of the use of this kind of materials. This review focuses on the overview of nanocellulose-based filter media, including its processing, desirable characteristics and recent developments regarding filtration, functionalization, biodegradability, and mechanical behavior. The porosity control, surface wettability and surface functional groups resulting from the silylation treatment to improve the filtration capacity of the nanocellulose-based membrane is discussed. Future research trends in this area are planned to develop the air filter media by reinforcing the filter membrane structure of CNF with CNCs. In addition, the integration of sol-gel technology into the production of an air filter can tailor the pore size of the membrane for a viable physical screening solution in future studies.
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Affiliation(s)
- Tido Tiwa Stanislas
- Laboratoire COVACHIM-M2E EA3592, UFR SEN, Université des Antilles, Campus de Fouillole, BP 250, 97157 Pointe-à-Pitre, Guadeloupe France
- Research Nucleus on Materials for Biosystems, Faculty of Animal Science and Food Engineering, University of São Paulo, Duque de Caxias Norte, 225, Pirassununga, SP 13635-900 Brazil
- Mechanic and Adapted Materials Laboratory, ENSET, University of Douala, P.O. BOX 1872, Douala, Cameroon
| | - Ketty Bilba
- Laboratoire COVACHIM-M2E EA3592, UFR SEN, Université des Antilles, Campus de Fouillole, BP 250, 97157 Pointe-à-Pitre, Guadeloupe France
| | - Rachel Passos de Oliveira Santos
- Research Nucleus on Materials for Biosystems, Faculty of Animal Science and Food Engineering, University of São Paulo, Duque de Caxias Norte, 225, Pirassununga, SP 13635-900 Brazil
| | - Cristel Onésippe-Potiron
- Laboratoire COVACHIM-M2E EA3592, UFR SEN, Université des Antilles, Campus de Fouillole, BP 250, 97157 Pointe-à-Pitre, Guadeloupe France
| | - Holmer Savastano Junior
- Research Nucleus on Materials for Biosystems, Faculty of Animal Science and Food Engineering, University of São Paulo, Duque de Caxias Norte, 225, Pirassununga, SP 13635-900 Brazil
| | - Marie-Ange Arsène
- Laboratoire COVACHIM-M2E EA3592, UFR SEN, Université des Antilles, Campus de Fouillole, BP 250, 97157 Pointe-à-Pitre, Guadeloupe France
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16
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Acuti Martellucci C, Flacco ME, Martellucci M, Violante FS, Manzoli L. Inhaled CO 2 Concentration While Wearing Face Masks: A Pilot Study Using Capnography. Environ Health Insights 2022; 16:11786302221123573. [PMID: 36133777 PMCID: PMC9483963 DOI: 10.1177/11786302221123573] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 08/10/2022] [Indexed: 05/21/2023]
Abstract
BACKGROUND Face masks are recommended based on the assumption that they protect against SARS-CoV-2 transmission, however studies on their potential side effects are still lacking. We aimed to evaluate the inhaled air carbon dioxide (CO2) concentration, when wearing masks. METHODS We measured end-tidal CO2 using professional side-stream capnography, with water-removing tubing, (1) without masks, (2) wearing a surgical mask, and (3) wearing a FFP2 respirator (for 5 minutes each while seated after 10 minutes of rest), in 146 healthy volunteers aged 10 to 90 years, from the general population of Ferrara, Italy. The inhaled air CO2 concentration was computed as: ([mask volume × end-tidal CO2] + [tidal volume - mask volume] × ambient air CO2)/tidal volume. RESULTS With surgical masks, the mean CO2 concentration was 7091 ± 2491 ppm in children, 4835 ± 869 in adults, and 4379 ± 978 in the elderly. With FFP2 respirators, this concentration was 13 665 ± 3655 in children, 8502 ± 1859 in adults, and 9027 ± 1882 in the elderly. The proportion showing a CO2 concentration higher than the 5000 ppm (8-hour average) acceptable threshold for workers was 41.1% with surgical masks, and 99.3% with FFP2 respirators. Adjusting for age, gender, BMI, and smoking, the inhaled air CO2 concentration significantly increased with increasing respiratory rate (mean 10 837 ±3712 ppm among participants ⩾18 breaths/minute, with FFP2 respirators), and among the minors. CONCLUSION If these results are confirmed, the current guidelines on mask-wearing should be reevaluated.
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Affiliation(s)
- Cecilia Acuti Martellucci
- Department of Environmental and
Prevention Sciences, University of Ferrara, Ferrara, Italy
- Cecilia Acuti Martellucci, Department of
Environmental and Prevention Sciences, University of Ferrara, Via Fossato di
Mortara 64/B, Ferrara 44121, Italy.
| | - Maria Elena Flacco
- Department of Environmental and
Prevention Sciences, University of Ferrara, Ferrara, Italy
| | - Mosè Martellucci
- Department of Medicine and Surgery,
University of Perugia, Perugia, Italy
| | - Francesco Saverio Violante
- Occupational Health Unit, Sant’Orsola
Malpighi University Hospital, University of Bologna, Bologna, Italy
| | - Lamberto Manzoli
- Department of Medical and Surgical
Sciences, University of Bologna, Bologna, Italy
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17
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Zheng K, Ortner P, Lim YW, Zhi TJ. Ventilation in worker dormitories and its impact on the spread of respiratory droplets. Sustain Cities Soc 2021; 75:103327. [PMID: 34545319 PMCID: PMC8443870 DOI: 10.1016/j.scs.2021.103327] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 08/31/2021] [Accepted: 08/31/2021] [Indexed: 05/29/2023]
Abstract
Most of the COVID-19 cases in Singapore have primarily come from foreign worker dormitories. This people group is especially vulnerable partly because of behavioural habits, but the built environment they live in also plays a significant role. These dormitories are typically densely populated, so the living conditions are cramped. The short lease given to most dormitories also means the design does not typically focus on environmental performance, like good natural ventilation. This paper seeks to understand how these dormitories' design affects natural ventilation and, subsequently, the spread of the COVID-19 particles by looking at two existing worker dorms in Singapore. Findings show that some rooms are poorly orientated against the prevailing wind directions, so there is dominant stagnant air in these rooms, leading to respiratory droplets' long residence times. These particles can hover in the air for 10 min and more. Interventions like increased bed distance and removing upper deck beds only showed limited ventilation improvements in some rooms. Comparatively, internal wind scoops' strategic placement was more effective at directing wind towards more stagnant zones. Large canyon aspect ratios were also effective at removing particles from higher elevations.
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Affiliation(s)
- Kai Zheng
- Architecture and Sustainable Design, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Peter Ortner
- Architecture and Sustainable Design, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Yu Wen Lim
- Architecture and Sustainable Design, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Tay Jing Zhi
- Architecture and Sustainable Design, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
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18
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Freeman AL, Parker S, Noakes C, Fitzgerald S, Smyth A, Macbeth R, Spiegelhalter D, Rutter H. Expert elicitation on the relative importance of possible SARS-CoV-2 transmission routes and the effectiveness of mitigations. BMJ Open 2021; 11:e050869. [PMID: 34853105 PMCID: PMC8637346 DOI: 10.1136/bmjopen-2021-050869] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/26/2021] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVES To help people make decisions about the most effective mitigation measures against SARS-CoV-2 transmission in different scenarios, the likelihoods of transmission by different routes need to be quantified to some degree (however uncertain). These likelihoods need to be communicated in an appropriate way to illustrate the relative importance of different routes in different scenarios, the likely effectiveness of different mitigation measures along those routes, and the level of uncertainty in those estimates. In this study, a pragmatic expert elicitation was undertaken to supply the underlying quantitative values to produce such a communication tool. PARTICIPANTS Twenty-seven individual experts from five countries and many scientific disciplines provided estimates. OUTCOME MEASURES Estimates of transmission parameters, assessments of the quality of the evidence, references to relevant literature, rationales for their estimates and sources of uncertainty. RESULTS AND CONCLUSION The participants' responses showed that there is still considerable disagreement among experts about the relative importance of different transmission pathways and the effectiveness of different mitigation measures due to a lack of empirical evidence. Despite these disagreements, when pooled, the majority views on each parameter formed an internally consistent set of estimates (for example, that transmission was more likely indoors than outdoors, and at closer range), which formed the basis of a visualisation to help individuals and organisations understand the factors that influence transmission and the potential benefits of different mitigation measures.
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Affiliation(s)
- Alexandra Lj Freeman
- Winton Centre for Risk & Evidence Communication, University of Cambridge, Cambridge, UK
| | - Simon Parker
- Defence Science and Technology Laboratory, Salisbury, UK
| | | | - Shaun Fitzgerald
- Centre for Climate Repair at Cambridge, University of Cambridge, Cambridge, UK
| | | | | | - David Spiegelhalter
- Winton Centre for Risk & Evidence Communication, University of Cambridge, Cambridge, UK
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19
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Matyka M. Pushing Droplet Through a Porous Medium. Transp Porous Media 2021; 144:55-68. [PMID: 34720283 PMCID: PMC8546388 DOI: 10.1007/s11242-021-01705-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 10/12/2021] [Indexed: 11/29/2022]
Abstract
I use a mechanical model of a soft body to study the dynamics of an individual fluid droplet in a random, non-wettable porous medium. The model of droplet relies on the spring–mass system with pressure. I run hundreds of independent simulations. I average droplets trajectories and calculate the averaged tortuosity of the porous domain. Results show that porous media tortuosity increases with decreasing porosity, similar to single-phase fluid study, but the form of this relationship is different.
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Affiliation(s)
- Maciej Matyka
- Faculty of Physics and Astronomy, University of Wrocław, pl. M. Borna 9, Wrocław, 50-204 Poland
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20
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Dietrich WL, Bennett JS, Jones BW, Hosni MH. Laboratory Modeling of SARS-CoV-2 Exposure Reduction Through Physically Distanced Seating in Aircraft Cabins Using Bacteriophage Aerosol - November 2020. MMWR Morb Mortal Wkly Rep 2021; 70:595-599. [PMID: 33886531 PMCID: PMC8061797 DOI: 10.15585/mmwr.mm7016e1] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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21
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Affiliation(s)
- Samiran Panda
- ICMR-National AIDS Research Institute, Pune 411 026, Maharashtra, India
- Division of Epidemiology and Communicable Diseases, New Delhi 110 029, India
| | - Harkiran Kaur
- Public Health Foundation of India, New Delhi 110 017, India
| | - Lalit Dandona
- Public Health Foundation of India, New Delhi 110 017, India
- Indian Council of Medical Research (ICMR), New Delhi 110 029, India
| | - Balram Bhargava
- Department of Health Research (ICMR), Ministry of Health & Family Welfare, New Delhi 110 001, India
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22
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Matovu JKB, Kabwama SN, Ssekamatte T, Ssenkusu J, Wanyenze RK. COVID-19 Awareness, Adoption of COVID-19 Preventive Measures, and Effects of COVID-19 Lockdown Among Adolescent Boys and Young Men in Kampala, Uganda. J Community Health 2021; 46:842-53. [PMID: 33481156 DOI: 10.1007/s10900-021-00961-w] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2021] [Indexed: 12/16/2022]
Abstract
There is growing evidence of the challenges with adherence to COVID-19 prevention measures and the effect of the prevention measures on the health of populations in various parts of the world but with limited documentation in sub-Saharan Africa. We assessed COVID-19 awareness, adoption of COVID-19 prevention measures, and the effects of COVID-19 lockdown on the mental health status, socio-economic disruptions and engagement in unhealthy behaviours among 2500 in- and out-of-school adolescent boys and young men (ABYM) aged 10–24 years in Kampala, Uganda. 74.8% (n = 1869) were in-school; nearly half (47.3%, n = 1182) were aged 15–19 years. Although > 80% were aware of at least two COVID-19 prevention measures, only 22.2% (n = 555) reported that they always wore a face mask while in a public place; 40.9% (n = 1023) always washed their hands with soap and running water while 17.6% (n = 440) always avoided gatherings of more than five people. COVID-19 lockdown led to: (a) increased mental health challenges (e.g. 1.2% [n = 31] contemplated committing suicide); (b) limited ability to meet basic needs (e.g. 62.0% [n = 1549] found it difficult to afford a diverse/balanced diet); (c) socio-economic disruptions (e.g. 30.3% [n = 756] experienced a reduction in income) and (d) engagement in unhealthy behaviours (e.g. 62% [n = 1554] reported a sedentary life style such as excessive watching of TV). These effects were more pronounced among older adolescent boys (15–19 years) and young men (20–24 years) and out-of-school compared to in-school ABYM. Our findings suggest a need for appropriate health promotion, mental health and socio-economic interventions targeting ABYM in Kampala, Uganda.
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23
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Viola IM, Peterson B, Pisetta G, Pavar G, Akhtar H, Menoloascina F, Mangano E, Dunn KE, Gabl R, Nila A, Molinari E, Cummins C, Thompson G, Lo TYM, Denison FC, Digard P, Malik O, Dunn MJG, McDougall CM, Mehendale FV. Face Coverings, Aerosol Dispersion and Mitigation of Virus Transmission Risk. IEEE Open J Eng Med Biol 2021; 2:26-35. [PMID: 34812420 PMCID: PMC8545035 DOI: 10.1109/ojemb.2021.3053215] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/02/2020] [Accepted: 01/12/2021] [Indexed: 11/15/2022] Open
Abstract
The SARS-CoV-2 virus is primarily transmitted through virus-laden fluid particles ejected from the mouth of infected people. Face covers can mitigate the risk of virus transmission but their outward effectiveness is not fully ascertained. Objective: by using a background oriented schlieren technique, we aim to investigate the air flow ejected by a person while quietly and heavily breathing, while coughing, and with different face covers. Results: we found that all face covers without an outlet valve reduce the front flow through by at least 63% and perhaps as high as 86% if the unfiltered cough jet distance was resolved to the anticipated maximum distance of 2-3 m. However, surgical and handmade masks, and face shields, generate significant leakage jets that may present major hazards. Conclusions: the effectiveness of the masks should mostly be considered based on the generation of secondary jets rather than on the ability to mitigate the front throughflow.
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Affiliation(s)
| | - Brian Peterson
- 1 School of EngineeringUniversity of Edinburgh Edinburgh EH9 3BF U.K
| | - Gabriele Pisetta
- 1 School of EngineeringUniversity of Edinburgh Edinburgh EH9 3BF U.K
| | - Geethanjali Pavar
- 1 School of EngineeringUniversity of Edinburgh Edinburgh EH9 3BF U.K
| | - Hibbah Akhtar
- 1 School of EngineeringUniversity of Edinburgh Edinburgh EH9 3BF U.K
- 2 Department of Mechanical EngineeringUniversity of Engineering and Technology Lahore Lahore 54890 Pakistan
| | | | - Enzo Mangano
- 1 School of EngineeringUniversity of Edinburgh Edinburgh EH9 3BF U.K
| | - Katherine E Dunn
- 1 School of EngineeringUniversity of Edinburgh Edinburgh EH9 3BF U.K
| | - Roman Gabl
- 1 School of EngineeringUniversity of Edinburgh Edinburgh EH9 3BF U.K
| | - Alex Nila
- 3 Lavision U.K. Ltd. Bicester EH8 9AB U.K
| | - Emanuela Molinari
- 4 School of InformaticsUniversity of Edinburgh Edinburgh EH14 4AS U.K
| | - Cathal Cummins
- 5 Maxwell Institute for Mathematical Sciences, Department of Mathematics and Institute for Infrastructure and EnvironmentHeriot-Watt University Edinburgh EH16 4SB U.K
| | - Gerard Thompson
- 6 Centre for Clinical Brain Sciences, University of Edinburgh Edinburgh EH16 4SB U.K
| | - Tsz-Yan Milly Lo
- 7 Paediatric Critical Care Unit, Royal Hospital for Sick Children Edinburgh EH16 4UX U.K
- 8 Usher InstituteUniversity of Edinburgh Edinburgh EH16 4UX U.K
| | - Fiona C Denison
- 9 The Queen's Medical Research InstituteUnivesity of Edinburgh Edinburgh EH16 4TJ U.K
| | - Paul Digard
- 10 The Roslin InstituteUniversity of Edinburgh Midlothian EH25 9RG U.K
| | - Omair Malik
- 11 Department of AnaesthesiaRoyal Hospital for Sick Children Edinburgh EH9 1LF U.K
| | - Mark J G Dunn
- 12 Department of Critical CareNHS Lothian Edinburgh EH1 3EG U.K
| | - Catherine M McDougall
- 7 Paediatric Critical Care Unit, Royal Hospital for Sick Children Edinburgh EH16 4UX U.K
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