101
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Figerez SP, Patra S, Rajalakshmi G, Narayanan TN. Graphene oxide-based rechargeable respiratory masks. OXFORD OPEN MATERIALS SCIENCE 2021; 1:itab003. [PMID: 38626262 PMCID: PMC8108635 DOI: 10.1093/oxfmat/itab003] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/20/2021] [Accepted: 01/24/2021] [Indexed: 12/23/2022]
Abstract
Respiratory masks having similar standards of 'N95', defined by the US National Institute for Occupational Safety and Health, will be highly sought after, post the current COVID-19 pandemic. Here, such a low-cost (∼$1/mask) mask design having electrostatic rechargeability and filtration efficiency of >95% with a quality factor of ∼20 kPa-1 is demonstrated. This filtration efficacy is for particles of size 300 nm. The tri-layer mask, named PPDFGO tri, contains nylon, modified polypropylene (PPY), and cotton nonwoven fabrics as three layers. The melt-spun PPY, available in a conventional N95 mask, modified with graphene oxide and polyvinylidene fluoride mixture containing paste using a simple solution casting method acts as active filtration layer. The efficacy of this tri-layer system toward triboelectric rechargeability using small mechanical agitations is demonstrated here. These triboelectric nanogenerator (TENG)-assisted membranes have high electrostatic charge retention capacity (∼1 nC/cm2 after 5 days in ambient condition) and high rechargeability even in very humid conditions (>80% RH). A simple but robust permeability measurement set up is also constructed to test these TENG-based membranes, where a flow rate of 30-35 L/min is maintained during the testing. Such a simple modification to the existing mask designs enabling their rechargeability via external mechanical disturbances, with enhanced usability for single use as well as for reuse with decontantamination, will be highly beneficial in the realm of indispensable personal protective equipment.
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Affiliation(s)
- Stelbin Peter Figerez
- Tata Institute of Fundamental Research - Hyderabad, Sy. No. 36/P Serilingampally Mandal, Gopanapally Village, Hyderabad - 500046, India
| | - Sudeshna Patra
- Tata Institute of Fundamental Research - Hyderabad, Sy. No. 36/P Serilingampally Mandal, Gopanapally Village, Hyderabad - 500046, India
| | - G Rajalakshmi
- Tata Institute of Fundamental Research - Hyderabad, Sy. No. 36/P Serilingampally Mandal, Gopanapally Village, Hyderabad - 500046, India
| | - Tharangattu N Narayanan
- Tata Institute of Fundamental Research - Hyderabad, Sy. No. 36/P Serilingampally Mandal, Gopanapally Village, Hyderabad - 500046, India
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102
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Hao W, Xu G, Wang Y. Factors influencing the filtration performance of homemade face masks. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2021; 18:128-138. [PMID: 33476218 DOI: 10.1080/15459624.2020.1868482] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The outbreak of the COVID-19 pandemic is causing a shortage of personal protective equipment (PPE) across the world. As a public health response to control the pandemic, wearing homemade face coverings has been proven as a resort to protect both the wearer and others from droplets and aerosols transmission. Although aerosols and droplets can be removed through these non-medical materials with a series of filtration mechanisms, their filtration performances have not been evaluated in detail. Moreover, many factors, such as the fabric properties and the method of usage, also affect filtration performance. In this study, the size-dependent filtration performances of non-medical materials as candidates for face coverings were evaluated comprehensively. The flow resistance across these filter materials, an indicator of breathability, was also examined. The effect of materials properties, washing and drying cycles, and triboelectric effect on particle filtration was also studied. Results showed that the filtration efficiency varied considerably from 5-50% among fabrics materials due to the material properties, such as density and microscopic structure of the materials. Microfiber cloth demonstrated the highest efficiency among the tested materials. In general, fabric materials with higher grams per square meter (GSM) show higher particle filtration efficiency. The results on washing and drying fabric materials indicated decent reusability for fabric materials. The triboelectric charge could increase the filtration performance of the tested fabric materials, but this effect diminishes soon due to the dissipation of charges, meaning that triboelectric charging may not be effective in manufacturing homemade face coverings.
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Affiliation(s)
- Weixing Hao
- Department of Civil, Architectural and Environmental Engineering, Missouri University of Science and Technology, Rolla, Missouri, USA
| | - Guang Xu
- Department of Mining Engineering, Missouri University of Science and Technology, Rolla, MO, USA
| | - Yang Wang
- Department of Civil, Architectural and Environmental Engineering, Missouri University of Science and Technology, Rolla, Missouri, USA
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103
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Pogačnik Krajnc A, Pirker L, Gradišar Centa U, Gradišek A, Mekjavic IB, Godnič M, Čebašek M, Bregant T, Remškar M. Size- and Time-Dependent Particle Removal Efficiency of Face Masks and Improvised Respiratory Protection Equipment Used during the COVID-19 Pandemic. SENSORS (BASEL, SWITZERLAND) 2021; 21:1567. [PMID: 33668141 PMCID: PMC7956512 DOI: 10.3390/s21051567] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/16/2021] [Accepted: 02/20/2021] [Indexed: 12/21/2022]
Abstract
Size- and time-dependent particle removal efficiency (PRE) of different protective respiratory masks were determined using a standard aerosol powder with the size of particles in the range of an uncoated SARS-CoV-2 virus and small respiratory droplets. Number concentration of particles was measured by a scanning mobility particle sizer. Respiratory protective half-masks, surgical masks, and cotton washable masks were tested. The results show high filtration efficiency of FFP2, FFP3, and certified surgical masks for all sizes of tested particles, while protection efficiency of washable masks depends on their constituent fabrics. Measurements showed decreasing PRE of all masks over time due to transmission of nanoparticles through the mask-face interface. On the other hand, the PRE of the fabric is governed by deposition of the aerosols, consequently increasing the PRE.
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Affiliation(s)
- Anja Pogačnik Krajnc
- Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (A.P.K.); (U.G.C.); (A.G.); (I.B.M.); (M.R.)
| | - Luka Pirker
- Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (A.P.K.); (U.G.C.); (A.G.); (I.B.M.); (M.R.)
| | - Urška Gradišar Centa
- Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (A.P.K.); (U.G.C.); (A.G.); (I.B.M.); (M.R.)
| | - Anton Gradišek
- Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (A.P.K.); (U.G.C.); (A.G.); (I.B.M.); (M.R.)
| | - Igor B. Mekjavic
- Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (A.P.K.); (U.G.C.); (A.G.); (I.B.M.); (M.R.)
| | - Matej Godnič
- Novo Mesto General Hospital, Šmihelska Cesta 1, 8000 Novo Mesto, Slovenia;
| | - Metod Čebašek
- HYLA d.o.o., Brnčičeva Ulica 47, 1231 Ljubljana, Slovenia;
| | | | - Maja Remškar
- Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (A.P.K.); (U.G.C.); (A.G.); (I.B.M.); (M.R.)
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska Cesta 19, 1000 Ljubljana, Slovenia
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104
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Ortelan N, Ferreira AJF, Leite L, Pescarini JM, Souto AC, Barreto ML, Aquino EML. Cloth masks in public places: an essential intervention to prevent COVID-19 in Brazil. CIENCIA & SAUDE COLETIVA 2021; 26:669-692. [PMID: 33605343 DOI: 10.1590/1413-81232021262.36702020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 11/02/2020] [Indexed: 02/08/2023] Open
Abstract
There is increasing evidence that the use of masks is an indispensable protective measure against COVID-19, given the high transmissibility of the new coronavirus through the respiratory system, including by asymptomatic individuals. The use of cloth masks in public places has been established as a protective measure to be adopted alongside social distancing and hand hygiene. This narrative review aims to systematize the scientific evidence that informs the widespread use of cloth masks as a preventive measure against COVID-19 and to describe the evolution of positions contrary to or in favor of its use outside the home, in view of the advance of the new coronavirus pandemic globally. The scientific articles, technical notes, governmental decrees and other documents analyzed indicate that widespread use of masks has the potential to reduce the spread of the new coronavirus. We recommend that the Brazilian government adopt strategies to increase the supply of reusable cloth masks to the public, especially to vulnerable populations and to support studies on the impact of this measure to control the pandemic in the country. Finally, it is imperative to ensure that use of masks does not exacerbate stigmatization of racial groups that already face prejudice.
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Affiliation(s)
- Naiá Ortelan
- Centro de Integração de Dados e Conhecimentos para Saúde, Fiocruz Bahia. R. Mundo s/n, Trobogy. 41745-715 Salvador BA Brasil.
| | | | | | - Julia Moreira Pescarini
- Centro de Integração de Dados e Conhecimentos para Saúde, Fiocruz Bahia. R. Mundo s/n, Trobogy. 41745-715 Salvador BA Brasil.
| | - Ana Cristina Souto
- Instituto de Saúde Coletiva, Universidade Federal da Bahia (UFBA). Salvador BA Brasil
| | - Mauricio Lima Barreto
- Centro de Integração de Dados e Conhecimentos para Saúde, Fiocruz Bahia. R. Mundo s/n, Trobogy. 41745-715 Salvador BA Brasil.
| | - Estela M L Aquino
- Instituto de Saúde Coletiva, Universidade Federal da Bahia (UFBA). Salvador BA Brasil
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105
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Lindsley WG, Blachere FM, Beezhold DH, Law BF, Derk RC, Hettick JM, Woodfork K, Goldsmith WT, Harris JR, Duling MG, Boutin B, Nurkiewicz T, Noti JD. A comparison of performance metrics for cloth face masks as source control devices for simulated cough and exhalation aerosols. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2021:2021.02.16.21251850. [PMID: 33619500 PMCID: PMC7899465 DOI: 10.1101/2021.02.16.21251850] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Universal mask wearing is recommended by the Centers for Disease Control and Prevention to help control the spread of COVID-19. Masks reduce the expulsion of respiratory aerosols (called source control) and offer some protection to the wearer. However, masks vary greatly in their designs and construction materials, and it is not clear which are most effective. Our study tested 15 reusable cloth masks (which included face masks, neck gaiters, and bandanas), two medical masks, and two N95 filtering facepiece respirators as source control devices for aerosols ≤ 7 µm produced during simulated coughing and exhalation. These measurements were compared with the mask filtration efficiencies, airflow resistances, and fit factors. The source control collection efficiencies for the cloth masks ranged from 17% to 71% for coughing and 35% to 66% for exhalation. The filtration efficiencies of the cloth masks ranged from 1.4% to 98%, while the fit factors were 1.3 to 7.4 on an elastomeric manikin headform and 1.0 to 4.0 on human test subjects. The correlation coefficients between the source control efficacies and the other performance metrics ranged from 0.31 to 0.66 and were significant in all but one case. However, none of the alternative metrics were strong predictors of the source control performance of cloth masks. Our results suggest that a better understanding of the relationships between source control performance and metrics like filtration efficiency, airflow resistance, and fit factor are needed to develop simple methods to estimate the effectiveness of masks as source control devices for respiratory aerosols.
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Affiliation(s)
- William G. Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Francoise M. Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Donald H. Beezhold
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Brandon F. Law
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Raymond C. Derk
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Justin M. Hettick
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Karen Woodfork
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
- Center for Inhalation Toxicology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - William T. Goldsmith
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
- Center for Inhalation Toxicology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - James R. Harris
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Matthew G. Duling
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Brenda Boutin
- National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Timothy Nurkiewicz
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
- Center for Inhalation Toxicology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - John D. Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
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106
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Xu M, Lee P, Collins D. The critical importance of mask seals on respirator performance: An analytical and simulation approach. PLoS One 2021; 16:e0246720. [PMID: 33596228 PMCID: PMC7888670 DOI: 10.1371/journal.pone.0246720] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 01/26/2021] [Indexed: 11/18/2022] Open
Abstract
Filtering facepiece respirators (FFRs) and medical masks are widely used to reduce the inhalation exposure of airborne particulates and biohazardous aerosols. Their protective capacity largely depends on the fraction of these that are filtered from the incoming air volume. While the performance and physics of different filter materials have been the topic of intensive study, less well understood are the effects of mask sealing. To address this, we introduce an approach to calculate the influence of face-seal leakage on filtration ratio and fit factor based on an analytical model and a finite element method (FEM) model, both of which take into account time-dependent human respiration velocities. Using these, we calculate the filtration ratio and fit factor for a range of ventilation resistance values relevant to filter materials, 500-2500 Pa∙s∙m-1, where the filtration ratio and fit factor are calculated as a function of the mask gap dimensions, with good agreement between analytical and numerical models. The results show that the filtration ratio and fit factor are decrease markedly with even small increases in gap area. We also calculate particle filtration rates for N95 FFRs with various ventilation resistances and two commercial FFRs exemplars. Taken together, this work underscores the critical importance of forming a tight seal around the face as a factor in mask performance, where our straightforward analytical model can be readily applied to obtain estimates of mask performance.
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Affiliation(s)
- Mingxin Xu
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria, Australia
| | - Peter Lee
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria, Australia
| | - David Collins
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria, Australia
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107
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Howard J, Huang A, Li Z, Tufekci Z, Zdimal V, van der Westhuizen HM, von Delft A, Price A, Fridman L, Tang LH, Tang V, Watson GL, Bax CE, Shaikh R, Questier F, Hernandez D, Chu LF, Ramirez CM, Rimoin AW. An evidence review of face masks against COVID-19. Proc Natl Acad Sci U S A 2021. [PMID: 33431650 DOI: 10.20944/preprints202004.0203.v1] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023] Open
Abstract
The science around the use of masks by the public to impede COVID-19 transmission is advancing rapidly. In this narrative review, we develop an analytical framework to examine mask usage, synthesizing the relevant literature to inform multiple areas: population impact, transmission characteristics, source control, wearer protection, sociological considerations, and implementation considerations. A primary route of transmission of COVID-19 is via respiratory particles, and it is known to be transmissible from presymptomatic, paucisymptomatic, and asymptomatic individuals. Reducing disease spread requires two things: limiting contacts of infected individuals via physical distancing and other measures and reducing the transmission probability per contact. The preponderance of evidence indicates that mask wearing reduces transmissibility per contact by reducing transmission of infected respiratory particles in both laboratory and clinical contexts. Public mask wearing is most effective at reducing spread of the virus when compliance is high. Given the current shortages of medical masks, we recommend the adoption of public cloth mask wearing, as an effective form of source control, in conjunction with existing hygiene, distancing, and contact tracing strategies. Because many respiratory particles become smaller due to evaporation, we recommend increasing focus on a previously overlooked aspect of mask usage: mask wearing by infectious people ("source control") with benefits at the population level, rather than only mask wearing by susceptible people, such as health care workers, with focus on individual outcomes. We recommend that public officials and governments strongly encourage the use of widespread face masks in public, including the use of appropriate regulation.
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Affiliation(s)
- Jeremy Howard
- fast.ai, San Francisco, CA 94105;
- Data Institute, University of San Francisco, San Francisco, CA 94105
| | - Austin Huang
- Warren Alpert School of Medicine, Brown University, Providence, RI 02903
| | - Zhiyuan Li
- Center for Quantitative Biology, Peking University, Beijing 100871, China
| | - Zeynep Tufekci
- School of Information, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Vladimir Zdimal
- Institute of Chemical Process Fundamentals, Czech Academy of Sciences, CZ-165 02 Praha 6, Czech Republic
| | - Helene-Mari van der Westhuizen
- Department of Primary Health Care Sciences, University of Oxford, Oxford OX2 6GG, United Kingdom
- TB Proof, Cape Town 7130, South Africa
| | - Arne von Delft
- TB Proof, Cape Town 7130, South Africa
- School of Public Health and Family Medicine, University of Cape Town, Cape Town 7925, South Africa
| | - Amy Price
- Anesthesia Informatics and Media Lab, School of Medicine, Stanford University, Stanford, CA 94305
| | - Lex Fridman
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Lei-Han Tang
- Department of Physics, Hong Kong Baptist University, Hong Kong SAR, China
- Complex Systems Division, Beijing Computational Science Research Center, Beijing 100193, China
| | - Viola Tang
- Department of Information Systems, Business Statistics and Operations Management, Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Gregory L Watson
- Department of Biostatistics, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, CA 90095
| | - Christina E Bax
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | | | - Frederik Questier
- Teacher Education Department, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | | | - Larry F Chu
- Anesthesia Informatics and Media Lab, School of Medicine, Stanford University, Stanford, CA 94305
| | - Christina M Ramirez
- Department of Biostatistics, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, CA 90095
| | - Anne W Rimoin
- Department of Epidemiology, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, CA 90095
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108
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Howard J, Huang A, Li Z, Tufekci Z, Zdimal V, van der Westhuizen HM, von Delft A, Price A, Fridman L, Tang LH, Tang V, Watson GL, Bax CE, Shaikh R, Questier F, Hernandez D, Chu LF, Ramirez CM, Rimoin AW. An evidence review of face masks against COVID-19. Proc Natl Acad Sci U S A 2021; 118:e2014564118. [PMID: 33431650 PMCID: PMC7848583 DOI: 10.1073/pnas.2014564118] [Citation(s) in RCA: 603] [Impact Index Per Article: 201.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The science around the use of masks by the public to impede COVID-19 transmission is advancing rapidly. In this narrative review, we develop an analytical framework to examine mask usage, synthesizing the relevant literature to inform multiple areas: population impact, transmission characteristics, source control, wearer protection, sociological considerations, and implementation considerations. A primary route of transmission of COVID-19 is via respiratory particles, and it is known to be transmissible from presymptomatic, paucisymptomatic, and asymptomatic individuals. Reducing disease spread requires two things: limiting contacts of infected individuals via physical distancing and other measures and reducing the transmission probability per contact. The preponderance of evidence indicates that mask wearing reduces transmissibility per contact by reducing transmission of infected respiratory particles in both laboratory and clinical contexts. Public mask wearing is most effective at reducing spread of the virus when compliance is high. Given the current shortages of medical masks, we recommend the adoption of public cloth mask wearing, as an effective form of source control, in conjunction with existing hygiene, distancing, and contact tracing strategies. Because many respiratory particles become smaller due to evaporation, we recommend increasing focus on a previously overlooked aspect of mask usage: mask wearing by infectious people ("source control") with benefits at the population level, rather than only mask wearing by susceptible people, such as health care workers, with focus on individual outcomes. We recommend that public officials and governments strongly encourage the use of widespread face masks in public, including the use of appropriate regulation.
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Affiliation(s)
- Jeremy Howard
- fast.ai, San Francisco, CA 94105;
- Data Institute, University of San Francisco, San Francisco, CA 94105
| | - Austin Huang
- Warren Alpert School of Medicine, Brown University, Providence, RI 02903
| | - Zhiyuan Li
- Center for Quantitative Biology, Peking University, Beijing 100871, China
| | - Zeynep Tufekci
- School of Information, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Vladimir Zdimal
- Institute of Chemical Process Fundamentals, Czech Academy of Sciences, CZ-165 02 Praha 6, Czech Republic
| | - Helene-Mari van der Westhuizen
- Department of Primary Health Care Sciences, University of Oxford, Oxford OX2 6GG, United Kingdom
- TB Proof, Cape Town 7130, South Africa
| | - Arne von Delft
- TB Proof, Cape Town 7130, South Africa
- School of Public Health and Family Medicine, University of Cape Town, Cape Town 7925, South Africa
| | - Amy Price
- Anesthesia Informatics and Media Lab, School of Medicine, Stanford University, Stanford, CA 94305
| | - Lex Fridman
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Lei-Han Tang
- Department of Physics, Hong Kong Baptist University, Hong Kong SAR, China
- Complex Systems Division, Beijing Computational Science Research Center, Beijing 100193, China
| | - Viola Tang
- Department of Information Systems, Business Statistics and Operations Management, Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Gregory L Watson
- Department of Biostatistics, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, CA 90095
| | - Christina E Bax
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | | | - Frederik Questier
- Teacher Education Department, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | | | - Larry F Chu
- Anesthesia Informatics and Media Lab, School of Medicine, Stanford University, Stanford, CA 94305
| | - Christina M Ramirez
- Department of Biostatistics, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, CA 90095
| | - Anne W Rimoin
- Department of Epidemiology, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, CA 90095
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109
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Howard J, Huang A, Li Z, Tufekci Z, Zdimal V, van der Westhuizen HM, von Delft A, Price A, Fridman L, Tang LH, Tang V, Watson GL, Bax CE, Shaikh R, Questier F, Hernandez D, Chu LF, Ramirez CM, Rimoin AW. An evidence review of face masks against COVID-19. Proc Natl Acad Sci U S A 2021; 118:2014564118. [PMID: 33431650 DOI: 10.20944/preprints202004.0203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023] Open
Abstract
The science around the use of masks by the public to impede COVID-19 transmission is advancing rapidly. In this narrative review, we develop an analytical framework to examine mask usage, synthesizing the relevant literature to inform multiple areas: population impact, transmission characteristics, source control, wearer protection, sociological considerations, and implementation considerations. A primary route of transmission of COVID-19 is via respiratory particles, and it is known to be transmissible from presymptomatic, paucisymptomatic, and asymptomatic individuals. Reducing disease spread requires two things: limiting contacts of infected individuals via physical distancing and other measures and reducing the transmission probability per contact. The preponderance of evidence indicates that mask wearing reduces transmissibility per contact by reducing transmission of infected respiratory particles in both laboratory and clinical contexts. Public mask wearing is most effective at reducing spread of the virus when compliance is high. Given the current shortages of medical masks, we recommend the adoption of public cloth mask wearing, as an effective form of source control, in conjunction with existing hygiene, distancing, and contact tracing strategies. Because many respiratory particles become smaller due to evaporation, we recommend increasing focus on a previously overlooked aspect of mask usage: mask wearing by infectious people ("source control") with benefits at the population level, rather than only mask wearing by susceptible people, such as health care workers, with focus on individual outcomes. We recommend that public officials and governments strongly encourage the use of widespread face masks in public, including the use of appropriate regulation.
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Affiliation(s)
- Jeremy Howard
- fast.ai, San Francisco, CA 94105;
- Data Institute, University of San Francisco, San Francisco, CA 94105
| | - Austin Huang
- Warren Alpert School of Medicine, Brown University, Providence, RI 02903
| | - Zhiyuan Li
- Center for Quantitative Biology, Peking University, Beijing 100871, China
| | - Zeynep Tufekci
- School of Information, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Vladimir Zdimal
- Institute of Chemical Process Fundamentals, Czech Academy of Sciences, CZ-165 02 Praha 6, Czech Republic
| | - Helene-Mari van der Westhuizen
- Department of Primary Health Care Sciences, University of Oxford, Oxford OX2 6GG, United Kingdom
- TB Proof, Cape Town 7130, South Africa
| | - Arne von Delft
- TB Proof, Cape Town 7130, South Africa
- School of Public Health and Family Medicine, University of Cape Town, Cape Town 7925, South Africa
| | - Amy Price
- Anesthesia Informatics and Media Lab, School of Medicine, Stanford University, Stanford, CA 94305
| | - Lex Fridman
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Lei-Han Tang
- Department of Physics, Hong Kong Baptist University, Hong Kong SAR, China
- Complex Systems Division, Beijing Computational Science Research Center, Beijing 100193, China
| | - Viola Tang
- Department of Information Systems, Business Statistics and Operations Management, Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Gregory L Watson
- Department of Biostatistics, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, CA 90095
| | - Christina E Bax
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | | | - Frederik Questier
- Teacher Education Department, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | | | - Larry F Chu
- Anesthesia Informatics and Media Lab, School of Medicine, Stanford University, Stanford, CA 94305
| | - Christina M Ramirez
- Department of Biostatistics, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, CA 90095
| | - Anne W Rimoin
- Department of Epidemiology, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, CA 90095
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110
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Lee HR, Liao L, Xiao W, Vailionis A, Ricco AJ, White R, Nishi Y, Chiu W, Chu S, Cui Y. Three-Dimensional Analysis of Particle Distribution on Filter Layers inside N95 Respirators by Deep Learning. NANO LETTERS 2021; 21:651-657. [PMID: 33283521 PMCID: PMC7737533 DOI: 10.1021/acs.nanolett.0c04230] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 11/25/2020] [Indexed: 05/22/2023]
Abstract
The global COVID-19 pandemic has changed many aspects of daily lives. Wearing personal protective equipment, especially respirators (face masks), has become common for both the public and medical professionals, proving to be effective in preventing spread of the virus. Nevertheless, a detailed understanding of respirator filtration-layer internal structures and their physical configurations is lacking. Here, we report three-dimensional (3D) internal analysis of N95 filtration layers via X-ray tomography. Using deep learning methods, we uncover how the distribution and diameters of fibers within these layers directly affect contaminant particle filtration. The average porosity of the filter layers is found to be 89.1%. Contaminants are more efficiently captured by denser fiber regions, with fibers <1.8 μm in diameter being particularly effective, presumably because of the stronger electric field gradient on smaller diameter fibers. This study provides critical information for further development of N95-type respirators that combine high efficiency with good breathability.
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Affiliation(s)
- Hye Ryoung Lee
- Geballe Laboratory for Advanced Materials,
Stanford University, Stanford, California 94305,
United States
- Stanford Institute for Materials and Energy Sciences,
SLAC National Accelerator Laboratory, Menlo Park, California
94025, United States
| | - Lei Liao
- 4C Air, Inc., Sunnyvale,
California 94089, United States
| | - Wang Xiao
- 4C Air, Inc., Sunnyvale,
California 94089, United States
| | - Arturas Vailionis
- Stanford Nano Shared Facility, Stanford
University, Stanford, California 94305, United
States
- Department of Physics, Kaunas University
of Technology, LT-51368 Kaunas, Lithuania
| | - Antonio J. Ricco
- Department of Electrical Engineering, Stanford
University, Stanford, California 94305, United
States
| | - Robin White
- Carl Zeiss X-ray Microscopy,
Inc., Pleasanton, California 94588, United States
| | - Yoshio Nishi
- Department of Electrical Engineering, Stanford
University, Stanford, California 94305, United
States
| | - Wah Chiu
- Department of Bioengineering, James H. Clark Center,
Stanford University, Stanford, California 94305,
United States
- Division of CryoEM and Bioimaging, SSRL,
SLAC National Accelerator Laboratory, Menlo Park, California
94025, United States
| | - Steven Chu
- Department of Physics, Stanford
University, Stanford, California 94305, United
States
- Department of Molecular and Cellular Physiology,
Stanford University, Stanford, California 94305,
United States
| | - Yi Cui
- Stanford Institute for Materials and Energy Sciences,
SLAC National Accelerator Laboratory, Menlo Park, California
94025, United States
- Department of Materials Science and Engineering,
Stanford University, Stanford, California 94305,
United States
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111
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Guha S, Herman A, Carr IA, Porter D, Natu R, Berman S, Myers MR. Comprehensive characterization of protective face coverings made from household fabrics. PLoS One 2021; 16:e0244626. [PMID: 33439878 PMCID: PMC7806137 DOI: 10.1371/journal.pone.0244626] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/15/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Face coverings constitute an important strategy for containing pandemics, such as COVID-19. Infection from airborne respiratory viruses including Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) can occur in at least three modes; tiny and/or dried aerosols (typically < 1.0 μm) generated through multiple mechanisms including talking, breathing, singing, large droplets (> 0.5 μm) generated during coughing and sneezing, and macro drops transmitted via fomites. While there is a growing number of studies looking at the performance of household materials against some of these situations, to date, there has not been any systematic characterization of household materials against all three modes. METHODS A three-step methodology was developed and used to characterize the performance of 21 different household materials with various material compositions (e.g. cotton, polyester, polypropylene, cellulose and blends) using submicron sodium chloride aerosols, water droplets, and mucous mimicking macro droplets over an aerosol-droplet size range of ~ 20 nm to 0.6 cm. RESULTS Except for one thousand-thread-count cotton, most single-layered materials had filtration efficiencies < 20% for sub-micron solid aerosols. However, several of these materials stopped > 80% of larger droplets, even at sneeze-velocities of up to 1700 cm/s. Three or four layers of the same material, or combination materials, would be required to stop macro droplets from permeating out or into the face covering. Such materials can also be boiled for reuse. CONCLUSION Four layers of loosely knit or woven fabrics independent of the composition (e.g. cotton, polyester, nylon or blends) are likely to be effective source controls. One layer of tightly woven fabrics combined with multiple layers of loosely knit or woven fabrics in addition to being source controls can have sub-micron filtration efficiencies > 40% and may offer some protection to the wearer. However, the pressure drop across such fabrics can be high (> 100 Pa).
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Affiliation(s)
- Suvajyoti Guha
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, United States Food and Drug Administration, Silver Spring, MD, United States of America
| | - Alexander Herman
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, United States Food and Drug Administration, Silver Spring, MD, United States of America
| | - Ian A. Carr
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, United States Food and Drug Administration, Silver Spring, MD, United States of America
| | - Daniel Porter
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, United States Food and Drug Administration, Silver Spring, MD, United States of America
| | - Rucha Natu
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, United States Food and Drug Administration, Silver Spring, MD, United States of America
| | - Shayna Berman
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, United States Food and Drug Administration, Silver Spring, MD, United States of America
| | - Matthew R. Myers
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, United States Food and Drug Administration, Silver Spring, MD, United States of America
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112
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Wang Y, Deng Z, Shi D. How effective is a mask in preventing COVID-19 infection? ACTA ACUST UNITED AC 2021; 4:e10163. [PMID: 33615150 PMCID: PMC7883189 DOI: 10.1002/mds3.10163] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/04/2020] [Accepted: 12/04/2020] [Indexed: 12/27/2022]
Abstract
The main clinical characteristics of COVID‐19 are respiratory symptoms that can lead to serious cardiovascular damages and severe worsening of other medical conditions. One of the major strategies in preparedness and response to COVID 19 is effective utilization of personal protective equipment (PPE) among which the masks of different kinds are on the top of the list especially for activities in the public places. However, the underlying mechanisms of masks in preventing virus transmission have not been well identified and the current experimental data still show inconsistent outcomes that may mislead the public. For instance, the early understanding of the mask functions was limited especially in the escalating phase of the COVID 19 pandemic, resulting in quite controversial remarks on masks. Although extensive studies in mask functions have been carried out ever since the COVID‐19 outbreaks, most of the investigations appear to have focused on exhalation isolation of individuals who may have been infected with the disease. Less emphasis was laid on inhalation protection from virus transmission, an important aspect that undergirds the public health policies and protective strategies. This review provides the most up‐to‐date information on the transmission modes of COVID‐19 virus in terms of droplets and aerosols. The roles of masks in disease prevention and transmission reduction are evaluated on various types, structures and functions. More important, both aspects of exhalation isolation and inhalation protection are discussed based on virus transmission modes and the effectiveness of different types of masks under varied environmental conditions.
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Affiliation(s)
- Yuxin Wang
- The Materials Science and Engineering Program College of Engineering and Applied Science University of Cincinnati Cincinnati OH USA
| | - Zicheng Deng
- The Materials Science and Engineering Program College of Engineering and Applied Science University of Cincinnati Cincinnati OH USA.,Center for Lung Regenerative Medicine Cincinnati Children's Hospital Medical Center Cincinnati OH USA.,Division of Pulmonary Biology Cincinnati Children's Hospital Medical Center Cincinnati OH USA
| | - Donglu Shi
- The Materials Science and Engineering Program College of Engineering and Applied Science University of Cincinnati Cincinnati OH USA
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113
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Prudhvi Krishna M, Babalola SA, Dutta S, Chakraborty SS, Thangadurai M, Roy H, Mandal N, Hirani H, Roy P. Effectiveness of different facemask materials to combat transmission of airborne diseases. SĀDHANĀ 2021; 46:119. [PMCID: PMC8208061 DOI: 10.1007/s12046-021-01634-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 02/20/2021] [Accepted: 04/29/2021] [Indexed: 05/29/2023]
Abstract
The pandemic COVID-19, caused by SARS-COV-2 virus has shaken the entire world with no such remedy till date. The only possible way to stop transmission of SARS-COV-2 is to take safety precautions including use of facemask. With the ever-increasing concern on the disease, it is necessary to choose facemask components to achieve the performance as good as commercially available N95 masks in a cost-effective way. This investigation compares the effectiveness of five different 3-layered masks with N95 mask in terms of pressure drop and aerosol filtration capabilities. Different combinations of cotton, polypropylene fabric, tissue and high-efficiency particulate air (HEPA) were used as mask materials. In comparison to N95 mask, the result shows that the 3-layered cotton mask has much lesser pressure drop but least droplet filtration efficiency, while polypropylene-HEPA-polypropylene mask is seen as the best cost-effective alternative to N95 in terms of droplets filtration efficiency and breathability. These findings are crucial to make the right non-medical facemask to combat COVID-19 and other airborne diseases. ![]()
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Affiliation(s)
- M Prudhvi Krishna
- CSIR – Central Mechanical Engineering Research Institute (CMERI), Mahatma Gandhi Avenue, Durgapur, West Bengal 713 209 India
| | - Simeon A Babalola
- CSIR – Central Mechanical Engineering Research Institute (CMERI), Mahatma Gandhi Avenue, Durgapur, West Bengal 713 209 India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002 India
| | - Samik Dutta
- CSIR – Central Mechanical Engineering Research Institute (CMERI), Mahatma Gandhi Avenue, Durgapur, West Bengal 713 209 India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002 India
| | - Shitanshu Shekhar Chakraborty
- CSIR – Central Mechanical Engineering Research Institute (CMERI), Mahatma Gandhi Avenue, Durgapur, West Bengal 713 209 India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002 India
| | - Murugan Thangadurai
- CSIR – Central Mechanical Engineering Research Institute (CMERI), Mahatma Gandhi Avenue, Durgapur, West Bengal 713 209 India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002 India
| | - Himadri Roy
- CSIR – Central Mechanical Engineering Research Institute (CMERI), Mahatma Gandhi Avenue, Durgapur, West Bengal 713 209 India
| | - Nilrudra Mandal
- CSIR – Central Mechanical Engineering Research Institute (CMERI), Mahatma Gandhi Avenue, Durgapur, West Bengal 713 209 India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002 India
| | - Harish Hirani
- CSIR – Central Mechanical Engineering Research Institute (CMERI), Mahatma Gandhi Avenue, Durgapur, West Bengal 713 209 India
- Department of Mechanical Engineering, Indian Institute of Technology, New Delhi, Delhi 110 016 India
| | - Poulomi Roy
- CSIR – Central Mechanical Engineering Research Institute (CMERI), Mahatma Gandhi Avenue, Durgapur, West Bengal 713 209 India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002 India
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114
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Ghatak B, Banerjee S, Ali SB, Bandyopadhyay R, Das N, Mandal D, Tudu B. Design of a self-powered triboelectric face mask. NANO ENERGY 2021; 79:105387. [PMID: 32983849 PMCID: PMC7502259 DOI: 10.1016/j.nanoen.2020.105387] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 09/10/2020] [Accepted: 09/13/2020] [Indexed: 05/02/2023]
Abstract
Usage of a face mask has become mandatory in many countries after the outbreak of SARS-CoV-2, and its usefulness in combating the pandemic is a proven fact. There have been many advancements in the design of a face mask and the present treatise describes a face mask in which a simple triboelectric nanogenerator (TENG) with an electrocution layer may serve the purpose of filtration and deactivation of SARS-CoV-2. The proposed mask is designed with multilayer filters, in which the inner three layers act as a triboelectric (TE) filter and the outer one as an electrocution layer (EL). The viral particles experience a mildshock in EL due to the electric field produced between the electrocution layers by contact electrification. Four pairs of triboelectric series fabrics, i.e. polyvinylchloride (PVC)-nylon, polypropylene (PP)-polyurethane (PU), latex rubber-PU, polyimide (PI)-nylon are studied to establish the efficacy of the mask. The motional force exerted on triboelectric filter materials can produce sufficient electric power to activate EL. The proposed mask can be used by a wide range of people because of its triboelectric self-powering (harvesting mechanical energy from daily activities, e.g. breathing, talking or other facial movements) functionalities to ensure effective filtration efficiency. More importantly, it is expected to be potentially beneficial to slow down the devastating impact of COVID-19.
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Affiliation(s)
- Barnali Ghatak
- Department of Instrumentation and Electronics Engineering, Jadavpur University, Kolkata, 700106, India
| | - Sanjoy Banerjee
- Department of Applied Electronics and Instrumentation Engineering, Future Institute of Engineering and Management, Kolkata, 700150, India
| | - Sk Babar Ali
- Department of Electronics and Communication Engineering, Future Institute of Engineering and Management, Kolkata, 700150, India
| | - Rajib Bandyopadhyay
- Department of Instrumentation and Electronics Engineering, Jadavpur University, Kolkata, 700106, India
- Laboratory of Artificial Sensory Systems, ITMO University, Saint Petersburg, 191002, Russia
| | - Nityananda Das
- Department of Physics, Jagannath Kishore College, Purulia, 723101, West Bengal, India
| | - Dipankar Mandal
- Institute of Nano Science and Technology (INST), Habitat Centre, Phase 10, Sector 64, Mohali, 160062, India
| | - Bipan Tudu
- Department of Instrumentation and Electronics Engineering, Jadavpur University, Kolkata, 700106, India
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115
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Sousa ITCD, Pestana AM, Pavanello L, Franz-Montan M, Cogo-Müller K. Máscaras caseiras na pandemia de COVID-19: recomendações, características físicas, desinfecção e eficácia de uso. EPIDEMIOLOGIA E SERVIÇOS DE SAÚDE 2021. [DOI: 10.1590/s1679-49742021000400003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Resumo Objetivo Descrever as recomendações, características físicas, métodos de desinfecção e eficácia de uso de máscaras caseiras na redução da transmissão da COVID-19. Métodos Realizou-se busca nas bases de dados MEDLINE, SciELO e Google Scholar, além das recomendações oficiais de uso. Resultados Foram incluídas 31 referências. A capacidade de filtração de tecidos variou entre 5% e 98%. Tecidos 100% algodão em duas ou três camadas apresentaram eficácia de filtração entre 70% e 99% em estudos in vitro. Máscaras caseiras, cirúrgicas e respiradores apresentaram respirabilidade entre 2,2 e 3,0 Pascal. A capacidade de redução da propagação de microrganismos por pessoas usando máscaras caseiras foi três vezes menor do que usando máscaras cirúrgicas, embora tenha sido superior ao não uso de máscaras. Conclusão A respirabilidade de máscaras caseiras mostrou-se adequada, enquanto a capacidade de filtração parece ser inferior à das máscaras cirúrgicas, mas superior a não se usar máscara. Não há evidências que respaldem a eficácia e efetividade das máscaras caseiras.
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116
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Han J, He S. Need for assessing the inhalation of micro(nano)plastic debris shed from masks, respirators, and home-made face coverings during the COVID-19 pandemic. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 268:115728. [PMID: 33065479 PMCID: PMC7537728 DOI: 10.1016/j.envpol.2020.115728] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 09/19/2020] [Accepted: 09/22/2020] [Indexed: 05/18/2023]
Affiliation(s)
- Jie Han
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, PR China.
| | - Shanshan He
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, PR China
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117
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Addressing the global challenge of access to supplies during COVID-19. ENVIRONMENTAL AND HEALTH MANAGEMENT OF NOVEL CORONAVIRUS DISEASE (COVID-19 ) 2021. [PMCID: PMC8237694 DOI: 10.1016/b978-0-323-85780-2.00008-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The current COVID-19 pandemic has presented unprecedented challenges for health care facilities worldwide. Global production and shipping routes were disrupted, and health care institutions, even in high resource areas, found themselves lacking the basic supplies for effective infection prevention and control. One major hurdle was the global access to supplies, particularly N95/FFP2 masks and alcohol-based hand rub (ABHR) for performing hand hygiene. This chapter explores how the lack of masks and ABHR were addressed through local production and the disinfection and reuse of disposable N95 masks. Although the global situation is no longer dire, the pandemic is currently still underway, and access to sufficient and high-quality supplies still is an important challenge faced by health care institutions. Previously, local production was mainly promoted by the World Health Organization (WHO) as a social business venture for helping developing countries. Disposable mask reuse was barely studied until this pandemic, because there was never really a need to. Thus the literature in these fields are mostly quite new. This chapter reviews the introduction and state of the art of the field, the evidence for hand hygiene and masking in the literature, the global situation since the pandemic and strategies that countries have taken to adapt. It then concentrates further on the specifics of local production, both for ABHR and for masks, and on the issues surrounding mask reuse. The chapter concludes with putting these technologies in the larger context of the pandemic, and how learning how the world tried to implement solutions can teach us lessons for future emergencies.
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118
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Chaiyabutr C, Sukakul T, Pruksaeakanan C, Thumrongtharadol J, Boonchai W. Adverse skin reactions following different types of mask usage during the COVID-19 pandemic. J Eur Acad Dermatol Venereol 2020; 35:e176-e178. [PMID: 33220083 PMCID: PMC7753376 DOI: 10.1111/jdv.17039] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- C Chaiyabutr
- Department of Dermatology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - T Sukakul
- Department of Dermatology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - C Pruksaeakanan
- Department of Dermatology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - J Thumrongtharadol
- Department of Dermatology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - W Boonchai
- Department of Dermatology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
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119
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Yim W, Cheng D, Patel SH, Kou R, Meng YS, Jokerst JV. KN95 and N95 Respirators Retain Filtration Efficiency despite a Loss of Dipole Charge during Decontamination. ACS APPLIED MATERIALS & INTERFACES 2020; 12:54473-54480. [PMID: 33253527 PMCID: PMC7724761 DOI: 10.1021/acsami.0c17333] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 11/18/2020] [Indexed: 05/03/2023]
Abstract
N95 decontamination protocols and KN95 respirators have been described as solutions to a lack of personal protective equipment. However, there are a few material science studies that characterize the charge distribution and physical changes accompanying disinfection treatments, particularly heating. Here, we report the filtration efficiency, dipole charge density, and fiber integrity of N95 and KN95 respirators before and after various decontamination methods. We found that the filter layers in N95 and KN95 respirators maintained their fiber integrity without any deformations during disinfection. The filter layers of N95 respirators were 8-fold thicker and had 2-fold higher dipole charge density than that of KN95 respirators. Emergency Use Authorization (EUA)-approved KN95 respirators showed filtration efficiencies as high as N95 respirators. Interestingly, although there was a significant drop in the dipole charge in both respirators during decontamination, there was no remarkable decrease in the filtration efficiencies due to mechanical filtration. Cotton and polyester face masks had a lower filtration efficiency and lower dipole charge. In conclusion, a loss of electrostatic charge does not directly correlate to the decreased performance of either respirator.
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Affiliation(s)
- Wonjun Yim
- Materials Science and Engineering Program, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, Unites States
| | - Diyi Cheng
- Materials Science and Engineering Program, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, Unites States
| | - Shiv H. Patel
- School of Medicine Simulation Training Center, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, Unites States
- Division of Biological Sciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, Unites States
| | - Rui Kou
- Department of Structural Engineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, Unites States
| | - Ying Shirley Meng
- Materials Science and Engineering Program, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, Unites States
- Department of Nanoengineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, Unites States
| | - Jesse V. Jokerst
- Materials Science and Engineering Program, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, Unites States
- Department of Nanoengineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, Unites States
- Department of Radiology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, Unites States
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120
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Han J, Zhang Y. Microfiber pillow as a potential harbor and environmental medium transmitting respiratory pathogens during the COVID-19 pandemic. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 205:111177. [PMID: 32916641 PMCID: PMC7434492 DOI: 10.1016/j.ecoenv.2020.111177] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/10/2020] [Accepted: 08/12/2020] [Indexed: 05/13/2023]
Abstract
• Pillows exposed to saliva, respiratory droplets, and exhaled breath during sleep. • Permeability of aerosols and saliva through cotton and polyester fabrics on pillows. • Pillows with microfiber fillings highly popular among US and Chinese consumers. • Microfiber pillows used on aircrafts, couchette trains, and in lodging facilities. • Current cleaning and disinfection protocols mainly target surfaces and fabrics.
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Affiliation(s)
- Jie Han
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, PR China.
| | - Yue Zhang
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, PR China
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121
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Xu J, Xiao X, Zhang W, Xu R, Kim SC, Cui Y, Howard TT, Wu E, Cui Y. Air-Filtering Masks for Respiratory Protection from PM 2.5 and Pandemic Pathogens. ONE EARTH (CAMBRIDGE, MASS.) 2020; 3:574-589. [PMID: 33748744 PMCID: PMC7962856 DOI: 10.1016/j.oneear.2020.10.014] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Air-filtering masks, also known as respirators, protect wearers from inhaling fine particulate matter (PM2.5) in polluted air, as well as airborne pathogens during a pandemic, such as the ongoing COVID-19 pandemic. Fibrous medium, used as the filtration layer, is the most essential component of an air-filtering mask. This article presents an overview of the development of fibrous media for air filtration. We first synthesize the literature on several key factors that affect the filtration performance of fibrous media. We then concentrate on two major techniques for fabricating fibrous media, namely, meltblown and electrospinning. In addition, we underscore the importance of electret filters by reviewing various methods for imparting electrostatic charge on fibrous media. Finally, this article concludes with a perspective on the emerging research opportunities amid the COVID-19 crisis.
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Affiliation(s)
- Jinwei Xu
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Xin Xiao
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Wenbo Zhang
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Rong Xu
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Sang Cheol Kim
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Yi Cui
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Tyler T Howard
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Esther Wu
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Yi Cui
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
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122
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Fortaleza CR, de Souza LDR, Rúgolo JM, Fortaleza CMCB. COVID-19: What we talk about when we talk about masks. Rev Soc Bras Med Trop 2020; 53:e20200527. [PMID: 33174963 PMCID: PMC7670747 DOI: 10.1590/0037-8682-0527-2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 09/24/2020] [Indexed: 11/22/2022] Open
Abstract
Even though most current recommendations include the general use of masks to prevent community transmission of SARS-Cov-2, the effectiveness of this measure is still debated. The studies on this policy include physical filtering tests with inanimate microparticles, randomized clinical trials, observational studies, ecological analyses, and even computational modeling of epidemics. Much of the so-called evidence is inferred from studies on different respiratory viruses and epidemiological settings. Heterogeneity is a major factor limiting the generalization of inferences. In this article, we reviewed the empirical and rational bases of mask use and how to understand these recommendations compared to other policies of social distancing, restrictions on non-essential services, and lockdown. We conclude that recent studies suggest a synergistic effect of the use of masks and social distancing rather than opposing effects of the two recommendations. Developing social communication approaches that clarify the need to combine different strategies is a challenge for public health authorities.
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Affiliation(s)
- Cristiane Ravagnani Fortaleza
- Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Hospital das Clínicas, Botucatu, SP, Brasil
- Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Programa de Pós-graduação em doenças infecciosas, Botucatu, SP, Brasil
| | - Lenice do Rosário de Souza
- Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Programa de Pós-graduação em doenças infecciosas, Botucatu, SP, Brasil
- Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Departamento de doenças infecciosas, Botucatu, SP, Brasil
| | - Juliana Machado Rúgolo
- Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Hospital das Clínicas, Botucatu, SP, Brasil
| | - Carlos Magno Castelo Branco Fortaleza
- Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Programa de Pós-graduação em doenças infecciosas, Botucatu, SP, Brasil
- Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Departamento de doenças infecciosas, Botucatu, SP, Brasil
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123
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Huang H, Park H, Liu Y, Huang J. On-Mask Chemical Modulation of Respiratory Droplets. MATTER 2020; 3:1791-1810. [PMID: 33163959 PMCID: PMC7598905 DOI: 10.1016/j.matt.2020.10.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/30/2020] [Accepted: 10/07/2020] [Indexed: 05/22/2023]
Abstract
Transmission of infectious respiratory diseases starts from pathogen-laden respiratory droplets released during coughing, sneezing, or speaking. Here we report an on-mask chemical modulation strategy, whereby droplets escaping a masking layer are chemically contaminated with antipathogen molecules (e.g., mineral acids or copper salts) preloaded on polyaniline-coated fabrics. A colorimetric method based on the color change of polyaniline and a fluorometric method utilizing fluorescence quenching microscopy are developed for visualizing the degree of modification of the escaped droplets by H+ and Cu2+, respectively. It is found that even fabrics with low fiber-packing densities (e.g., 19%) can readily modify 49% of the escaped droplets by number, which accounts for about 82% by volume. The chemical modulation strategy could offer additional public health benefits to the use of face covering to make the sources less infectious, helping to strengthen the response to the current pandemic or future outbreaks of infectious respiratory diseases.
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Affiliation(s)
- Haiyue Huang
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Hun Park
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Yihan Liu
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Jiaxing Huang
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
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124
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Sheets D, Shaw J, Baldwin M, Daggett D, Elali I, Curry EB, Sochnikov I, Hancock JN. An apparatus for rapid and nondestructive comparison of masks and respirators. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:114101. [PMID: 33261462 DOI: 10.1063/5.0015983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 09/29/2020] [Indexed: 06/12/2023]
Abstract
The SARS-CoV-2 global pandemic has produced widespread shortages of certified air-filtering personal protection equipment and an acute need for rapid evaluation of breathability and filtration efficiency of proposed alternative solutions. Here, we describe experimental efforts to nondestructively quantify three vital characteristics of mask approaches: breathability, material filtration effectiveness, and sensitivity to fit. We focus on protection against aqueous aerosols >0.3 μm using off-the-shelf particle, flow, and pressure sensors, permitting rapid comparative evaluation of these three properties. We present and discuss both the pressure drop and the particle penetration as a function of flow to permit comparison of relative protection for a set of proposed filter and mask designs. The design considerations of the testing apparatus can be reproduced by university laboratories and medical facilities and used for rapid local quality control of respirator masks that are of uncertified origin, monitoring the long-term effects of various disinfection schemes and evaluating improvised products not designed or marketed for filtration.
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Affiliation(s)
- Donal Sheets
- Institute of Material Science, University of Connecticut, Storrs, Connecticut 06269, USA
| | - Jamie Shaw
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, USA
| | - Michael Baldwin
- Department of Diagnostic Imaging, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - David Daggett
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269, USA
| | - Ibrahim Elali
- Division of Nephrology, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
| | - Erin B Curry
- Institute of Material Science, University of Connecticut, Storrs, Connecticut 06269, USA
| | - Ilya Sochnikov
- Institute of Material Science, University of Connecticut, Storrs, Connecticut 06269, USA
| | - Jason N Hancock
- Institute of Material Science, University of Connecticut, Storrs, Connecticut 06269, USA
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125
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Wibisono Y, Fadila CR, Saiful S, Bilad MR. Facile Approaches of Polymeric Face Masks Reuse and Reinforcements for Micro-Aerosol Droplets and Viruses Filtration: A Review. Polymers (Basel) 2020; 12:E2516. [PMID: 33126730 PMCID: PMC7692770 DOI: 10.3390/polym12112516] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 12/23/2022] Open
Abstract
Since the widespread of severe acute respiratory syndrome of coronavirus 2 (SARS-CoV-2) disease, the utilization of face masks has become omnipresent all over the world. Face masks are believed to contribute to an adequate protection against respiratory infections spread through micro-droplets among the infected person to non-infected others. However, due to the very high demands of face masks, especially the N95-type mask typically worn by medical workers, the public faces a shortage of face masks. Many papers have been published recently that focus on developing new and facile techniques to reuse and reinforce commercially available face masks. For instance, the N95 mask uses a polymer-based (membrane) filter inside, and the filter membrane can be replaced if needed. Another polymer sputtering technique by using a simple cotton candy machine could provide a cheap and robust solution for face mask fabrication. This review discuss the novel approaches of face mask reuse and reinforcement specifically by using membrane-based technology. Tuning the polymeric properties of face masks to enhance filterability and virus inactivity is crucial for future investigation.
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Affiliation(s)
- Yusuf Wibisono
- Department of Bioprocess Engineering, Faculty of Agricultural Technology, Brawijaya University, Malang 65141, Indonesia;
| | - Cut Rifda Fadila
- Department of Bioprocess Engineering, Faculty of Agricultural Technology, Brawijaya University, Malang 65141, Indonesia;
| | - Saiful Saiful
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Banda Aceh 23111, Indonesia;
| | - Muhammad Roil Bilad
- Department of Chemical Engineering, Faculty of Engineering, Universiti Teknologi Petronas, Bandar Seri Iskandar 32610, Malaysia;
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126
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Campos RK, Jin J, Rafael GH, Zhao M, Liao L, Simmons G, Chu S, Weaver SC, Chiu W, Cui Y. Decontamination of SARS-CoV-2 and Other RNA Viruses from N95 Level Meltblown Polypropylene Fabric Using Heat under Different Humidities. ACS NANO 2020; 14:14017-14025. [PMID: 32955847 PMCID: PMC7526332 DOI: 10.1021/acsnano.0c06565] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 09/21/2020] [Indexed: 05/09/2023]
Abstract
In March of 2020, the World Health Organization declared a pandemic of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The pandemic led to a shortage of N95-grade filtering facepiece respirators (FFRs), especially surgical-grade N95 FFRs for protection of healthcare professionals against airborne transmission of SARS-CoV-2. We and others have previously reported promising decontamination methods that may be applied to the recycling and reuse of FFRs. In this study we tested disinfection of three viruses, including SARS-CoV-2, dried on a piece of meltblown fabric, the principal component responsible for filtering of fine particles in N95-level FFRs, under a range of temperatures (60-95 °C) at ambient or 100% relative humidity (RH) in conjunction with filtration efficiency testing. We found that heat treatments of 75 °C for 30 min or 85 °C for 20 min at 100% RH resulted in efficient decontamination from the fabric of SARS-CoV-2, human coronavirus NL63 (HCoV-NL63), and another enveloped RNA virus, chikungunya virus vaccine strain 181/25 (CHIKV-181/25), without lowering the meltblown fabric's filtration efficiency.
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Affiliation(s)
- Rafael K. Campos
- Department of Microbiology and
Immunology, University of Texas Medical
Branch, Galveston, Texas 77550, United
States
| | - Jing Jin
- Vitalant Research
Institute, San Francisco, California 94118,
United States
- Division of CryoEM and Bioimaging, SSRL,
SLAC National Accelerator Laboratory,
Menlo Park, California 94025, United States
| | - Grace H. Rafael
- Department of Microbiology and
Immunology, University of Texas Medical
Branch, Galveston, Texas 77550, United
States
| | - Mervin Zhao
- 4C Air,
Inc., Sunnyvale, California 94089, United
States
| | - Lei Liao
- 4C Air,
Inc., Sunnyvale, California 94089, United
States
| | - Graham Simmons
- Vitalant Research
Institute, San Francisco, California 94118,
United States
| | - Steven Chu
- Department of Physics,
Stanford University, Stanford,
California 94305, United States
- Department of Molecular
and Cellular Physiology, Stanford, California
94305, United States
| | - Scott C. Weaver
- Department of Microbiology and
Immunology, University of Texas Medical
Branch, Galveston, Texas 77550, United
States
- Institute for Human Infections and
Immunity, University of Texas Medical
Branch, Galveston, Texas 77550, United
States
| | - Wah Chiu
- Division of CryoEM and Bioimaging, SSRL,
SLAC National Accelerator Laboratory,
Menlo Park, California 94025, United States
- Department of Bioengineering,
Stanford University, Stanford,
California 94305, United States
| | - Yi Cui
- Department of Materials Science and
Engineering, Stanford University, Stanford,
California 94305, United States
- Stanford Institute for Materials and
Energy Sciences, SLAC National Accelerator
Laboratory, Menlo Park, California 94025,
United States
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127
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Hill WC, Hull MS, MacCuspie RI. Testing of Commercial Masks and Respirators and Cotton Mask Insert Materials using SARS-CoV-2 Virion-Sized Particulates: Comparison of Ideal Aerosol Filtration Efficiency versus Fitted Filtration Efficiency. NANO LETTERS 2020; 20:7642-7647. [PMID: 32986441 PMCID: PMC7534799 DOI: 10.1021/acs.nanolett.0c03182] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/24/2020] [Indexed: 05/18/2023]
Abstract
Shortages in the availability of personal protective face masks during the COVID-19 pandemic required many to fabricate masks and filter inserts from available materials. While the base filtration efficiency of a material is of primary importance when a perfect seal is possible, ideal fit is not likely to be achieved by the average person preparing to enter a public space or even a healthcare worker without fit-testing before each shift. Our findings suggest that parameters including permeability and pliability can play a strong role in the filtration efficiency of a mask fabricated with various filter media, and that the filtration efficiency of loosely fitting masks/respirators against ultrafine particulates can drop by more than 60% when worn compared to the ideal filtration efficiency of the base material. Further, a test method using SARS-CoV-2 virion-sized silica nanoaerosols is demonstrated to assess the filtration efficiency against nanoparticulates that follow air currents associated with mask leakage.
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Affiliation(s)
- W Cary Hill
- NanoSafe, Inc., 1800 Kraft Drive, Suite 107, Blacksburg, Virginia 24060, United States
| | - Matthew S Hull
- NanoSafe, Inc., 1800 Kraft Drive, Suite 107, Blacksburg, Virginia 24060, United States
- Institute for Critical Technology and Applied Science, Virginia Tech, Kelly Hall (MC0193), Blacksburg, Virginia 24061, United States
| | - Robert I MacCuspie
- NanoSafe, Inc., 1800 Kraft Drive, Suite 107, Blacksburg, Virginia 24060, United States
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128
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Zhao L, Qi Y, Luzzatto-Fegiz P, Cui Y, Zhu Y. COVID-19: Effects of Environmental Conditions on the Propagation of Respiratory Droplets. NANO LETTERS 2020; 20:7744-7750. [PMID: 32909761 PMCID: PMC7496593 DOI: 10.1021/acs.nanolett.0c03331] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/09/2020] [Indexed: 05/20/2023]
Abstract
As coronavirus disease 2019 (COVID-19) continues to spread, a detailed understanding on the transmission mechanisms is of paramount importance. The disease transmits mainly through respiratory droplets and aerosol. Although models for the evaporation and trajectory of respiratory droplets have been developed, how the environment impacts the transmission of COVID-19 is still unclear. In this study, we investigate the propagation of respiratory droplets and aerosol particles generated by speech under a wide range of temperatures (0-40 °C) and relative humidity (0-92%) conditions. We show that droplets can travel three times farther in low-temperature and high-humidity environment, whereas the number of aerosol particles increases in high-temperature and low-humidity environments. The results also underscore the importance of proper ventilation, as droplets and aerosol spread significantly farther in airstreams. This study contributes to the understanding of the environmental impact on COVID-19 transmission.
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Affiliation(s)
- Lei Zhao
- Department of Mechanical Engineering,
University of California Santa
Barbara, Santa Barbara, California 93106,
United States
| | - Yuhang Qi
- Department of Mechanical Engineering,
University of California Santa
Barbara, Santa Barbara, California 93106,
United States
| | - Paolo Luzzatto-Fegiz
- Department of Mechanical Engineering,
University of California Santa
Barbara, Santa Barbara, California 93106,
United States
| | - Yi Cui
- Department of Materials Science and
Engineering, Stanford University, Stanford,
California 94305, United States
- Stanford Institute for Materials and
Energy Sciences, SLAC National Accelerator
Laboratory, Menlo Park, California 94025,
United States
| | - Yangying Zhu
- Department of Mechanical Engineering,
University of California Santa
Barbara, Santa Barbara, California 93106,
United States
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129
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Zhao L, Qi Y, Luzzatto-Fegiz P, Cui Y, Zhu Y. COVID-19: Effects of Environmental Conditions on the Propagation of Respiratory Droplets. NANO LETTERS 2020; 20:7744-7750. [PMID: 32909761 DOI: 10.1101/2020.05.24.20111963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
As coronavirus disease 2019 (COVID-19) continues to spread, a detailed understanding on the transmission mechanisms is of paramount importance. The disease transmits mainly through respiratory droplets and aerosol. Although models for the evaporation and trajectory of respiratory droplets have been developed, how the environment impacts the transmission of COVID-19 is still unclear. In this study, we investigate the propagation of respiratory droplets and aerosol particles generated by speech under a wide range of temperatures (0-40 °C) and relative humidity (0-92%) conditions. We show that droplets can travel three times farther in low-temperature and high-humidity environment, whereas the number of aerosol particles increases in high-temperature and low-humidity environments. The results also underscore the importance of proper ventilation, as droplets and aerosol spread significantly farther in airstreams. This study contributes to the understanding of the environmental impact on COVID-19 transmission.
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Affiliation(s)
- Lei Zhao
- Department of Mechanical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Yuhang Qi
- Department of Mechanical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Paolo Luzzatto-Fegiz
- Department of Mechanical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Yi Cui
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Yangying Zhu
- Department of Mechanical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
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130
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Clase CM, Fu EL, Ashur A, Beale RCL, Clase IA, Dolovich MB, Jardine MJ, Joseph M, Kansiime G, Mann JFE, Pecoits-Filho R, Winkelmayer WC, Carrero JJ. Forgotten Technology in the COVID-19 Pandemic: Filtration Properties of Cloth and Cloth Masks-A Narrative Review. Mayo Clin Proc 2020; 95:2204-2224. [PMID: 33012350 PMCID: PMC7834536 DOI: 10.1016/j.mayocp.2020.07.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 07/23/2020] [Indexed: 12/20/2022]
Abstract
Management of the global crisis of the coronavirus disease 2019 pandemic requires detailed appraisal of evidence to support clear, actionable, and consistent public health messaging. The use of cloth masks for general public use is being debated, and is in flux. We searched the MEDLINE and EMBASE databases and Google for articles reporting the filtration properties of flat cloth or cloth masks. We reviewed the reference lists of relevant articles to identify further articles and identified articles through social and conventional news media. We found 25 articles. Study of protection for the wearer used healthy volunteers, or used a manikin wearing a mask, with airflow to simulate different breathing rates. Studies of protection of the environment, also known as source control, used convenience samples of healthy volunteers. The design and execution of the studies was generally rigorously described. Many descriptions of cloth lacked the detail required for reproducibility; no study provided all the expected details of material, thread count, weave, and weight. Some of the homemade mask designs were reproducible. Successful masks were made of muslin at 100 threads per inch (TPI) in 3 to 4 layers (4-layer muslin or a muslin-flannel-muslin sandwich), tea towels (also known as dish towels), made using 1 layer (2 layers would be expected to be better), and good-quality cotton T-shirts in 2 layers (with a stitched edge to prevent stretching). In flat-cloth experiments, linen tea towels, 600-TPI cotton in 2 layers, and 600-TPI cotton with 90-TPI flannel performed well but 80-TPI cotton in 2 layers did not. We therefore recommend cotton or flannel at least 100 TPI, at least 2 layers. More layers, 3 or 4, will provide increased filtration but there is a trade-off in that more layers increases the resistance to breathing. Although this is not a systematic review, we included all the articles that we identified in an unbiased way. We did not include gray literature or preprints. A plain language summary of these data and recommendations, as well as information on making, wearing and cleaning cloth masks is available at www.clothmasks.ca.
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Affiliation(s)
- Catherine M Clase
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada; Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada; St Joseph's Healthcare Hamilton, Hamilton, Canada; Centre of Excellence in Protective Equipment and Materials.
| | - Edouard L Fu
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Aurneen Ashur
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | | | - Imogen A Clase
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Myrna B Dolovich
- Division of Respirology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Meg J Jardine
- The George Institute for Global Health and Concord Repatriation General Hospital, Sydney, Australia
| | - Meera Joseph
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada; Mulago National Referral Hospital, Kampala, Uganda
| | - Grace Kansiime
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Johannes F E Mann
- Department of Nephrology, Hypertension & Rheumatology at Munich General Hospitals, University of Erlangen-Nürnberg, KfH Kidney Center, Munich-Schwabing, Germany
| | - Roberto Pecoits-Filho
- DOPPS Program, Arbor Research Collaborative for Health, Ann Arbor, MI, and School of Medicine, Pontifical Catholic University of Paraná, Curitiba, Brazil
| | | | - Juan J Carrero
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
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131
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Alenezi H, Cam ME, Edirisinghe M. A novel reusable anti-COVID-19 transparent face respirator with optimized airflow. Biodes Manuf 2020; 4:1-9. [PMID: 33014512 PMCID: PMC7520078 DOI: 10.1007/s42242-020-00097-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 09/07/2020] [Indexed: 12/23/2022]
Abstract
This novel face mask is designed to be a reusable respirator with a small and highly efficient disposable fabric filter. Respirator material requirements are reduced by 75% compared to traditional designs and allow repeated cleaning or sterilization. The probability of virus particle inhalation is reduced using novel air filtration pathways, through square-waveform design to increase filter airflow. Air enters the mask from right and left side filters, while the area in front of the mouth is isolated. Clear epoxy is used for a transparent frame, allowing lip-reading, and mask edges contain a silicone seal preventing bypass of the filters. The mask is manufactured using silicone molds, eliminating electricity requirements making it economical and viable in developing countries. Computational fluid dynamics numerical studies and Fluent ANSYS software were used to simulate airflow through the filter to optimize filter air path geometry and validate mask design with realistic human requirements. The breathing cycle was represented as a transient function, and N95 filter specifications were selected as a porous medium. The novel design achieved 1.2 × 10−3 kg s−1, 20% higher than human requirements, with air streamlines velocity indicating local high speed, forcing and trapping virus particles against filter walls through centrifugal forces.
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Affiliation(s)
- Hussain Alenezi
- Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE UK
- Department of Manufacturing Engineering, College of Technological Studies, PAAET, 13092 Kuwait City, Kuwait
| | - Muhammet Emin Cam
- Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE UK
- Center for Nanotechnology and Biomaterials Application and Research, Marmara University, 34722 Istanbul, Turkey
| | - Mohan Edirisinghe
- Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE UK
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132
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Hancock JN, Plumley MJ, Schilling K, Sheets D, Wilen L. Comment on "Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks". ACS NANO 2020; 14:10758-10763. [PMID: 32961642 DOI: 10.1021/acsnano.0c05827] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Affiliation(s)
- Jason N Hancock
- Institute of Material Science, University of Connecticut, Storrs, Connecticut 06269, United States
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Michael J Plumley
- Department of Mechanical Engineering, United States Coast Guard Academy, New London, Connecticut 06320, United States
| | - Katherine Schilling
- Department of Chemical and Environmental Engineering, School of Engineering and Applied Science, Yale University, New Haven, Connecticut 06511, United States
| | - Donal Sheets
- Institute of Material Science, University of Connecticut, Storrs, Connecticut 06269, United States
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Lawrence Wilen
- School of Engineering and Applied Science, Yale University, New Haven, Connecticut 06511, United States
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133
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Hossain E, Bhadra S, Jain H, Das S, Bhattacharya A, Ghosh S, Levine D. Recharging and rejuvenation of decontaminated N95 masks. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2020; 32:093304. [PMID: 32982134 PMCID: PMC7513826 DOI: 10.1063/5.0023940] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 08/12/2020] [Indexed: 05/03/2023]
Abstract
N95 respirators comprise a critical part of the personal protective equipment used by frontline health-care workers and are typically meant for one-time usage. However, the recent COVID-19 pandemic has resulted in a serious shortage of these masks leading to a worldwide effort to develop decontamination and re-use procedures. A major factor contributing to the filtration efficiency of N95 masks is the presence of an intermediate layer of charged polypropylene electret fibers that trap particles through electrostatic or electrophoretic effects. This charge can degrade when the mask is used. Moreover, simple decontamination procedures (e.g., use of alcohol) can degrade any remaining charge from the polypropylene, thus severely impacting the filtration efficiency post-decontamination. In this report, we summarize our results on the development of a simple laboratory setup allowing measurement of charge and filtration efficiency in N95 masks. In particular, we propose and show that it is possible to recharge the masks post-decontamination and recover filtration efficiency.
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Affiliation(s)
- Emroj Hossain
- Department of Condensed Matter Physics and
Materials Science, Tata Institute of Fundamental Research, Mumbai 400005,
India
| | - Satyanu Bhadra
- Department of Condensed Matter Physics and
Materials Science, Tata Institute of Fundamental Research, Mumbai 400005,
India
| | - Harsh Jain
- Department of Condensed Matter Physics and
Materials Science, Tata Institute of Fundamental Research, Mumbai 400005,
India
| | - Soumen Das
- Department of Condensed Matter Physics and
Materials Science, Tata Institute of Fundamental Research, Mumbai 400005,
India
| | - Arnab Bhattacharya
- Department of Condensed Matter Physics and
Materials Science, Tata Institute of Fundamental Research, Mumbai 400005,
India
| | - Shankar Ghosh
- Department of Condensed Matter Physics and
Materials Science, Tata Institute of Fundamental Research, Mumbai 400005,
India
| | - Dov Levine
- Department of Physics, Technion-IIT,
32000 Haifa, Israel
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134
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Zangmeister CD, Radney JG, Vicenzi EP, Weaver JL. Filtration Efficiencies of Nanoscale Aerosol by Cloth Mask Materials Used to Slow the Spread of SARS-CoV-2. ACS NANO 2020; 14:9188-9200. [PMID: 32584542 PMCID: PMC7341689 DOI: 10.1021/acsnano.0c05025] [Citation(s) in RCA: 135] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 06/25/2020] [Indexed: 05/17/2023]
Abstract
Filtration efficiency (FE), differential pressure (ΔP), quality factor (QF), and construction parameters were measured for 32 cloth materials (14 cotton, 1 wool, 9 synthetic, 4 synthetic blends, and 4 synthetic/cotton blends) used in cloth masks intended for protection from the SARS-CoV-2 virus (diameter 100 ± 10 nm). Seven polypropylene-based fiber filter materials were also measured including surgical masks and N95 respirators. Additional measurements were performed on both multilayered and mixed-material samples of natural, synthetic, or natural-synthetic blends to mimic cloth mask construction methods. Materials were microimaged and tested against size selected NaCl aerosol with particle mobility diameters between 50 and 825 nm. Three of the top five best performing samples were woven 100% cotton with high to moderate yarn counts, and the other two were woven synthetics of moderate yarn counts. In contrast to recently published studies, samples utilizing mixed materials did not exhibit a significant difference in the measured FE when compared to the product of the individual FE for the components. The FE and ΔP increased monotonically with the number of cloth layers for a lightweight flannel, suggesting that multilayered cloth masks may offer increased protection from nanometer-sized aerosol with a maximum FE dictated by breathability (i.e., ΔP).
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Affiliation(s)
- Christopher D. Zangmeister
- Material Measurement Laboratory, National
Institute of Standards and Technology, Gaithersburg, Maryland 20899,
United States
| | - James G. Radney
- Material Measurement Laboratory, National
Institute of Standards and Technology, Gaithersburg, Maryland 20899,
United States
| | - Edward P. Vicenzi
- Material Measurement Laboratory, National
Institute of Standards and Technology, Gaithersburg, Maryland 20899,
United States
- Museum Conservation Institute,
Smithsonian Institution, Suitland, Maryland 20746,
United States
| | - Jamie L. Weaver
- Material Measurement Laboratory, National
Institute of Standards and Technology, Gaithersburg, Maryland 20899,
United States
- Museum Conservation Institute,
Smithsonian Institution, Suitland, Maryland 20746,
United States
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135
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Wood-Black F, Lewin J, Blayney MB, Galindo L, Foreman R, Zelivyanskaya M, Reid M. Highlights: Reusing Masks, Face Covering Efficacy, Plant Restarts, and More: Submit contributions to highlights@safety.acs.org and be coauthored, or share ideas on social media with #SafetyHighlights. ACS CHEMICAL HEALTH & SAFETY 2020; 27:204-208. [PMID: 34191961 PMCID: PMC7374814 DOI: 10.1021/acs.chas.0c00069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Jeff Lewin
- Campus
Safety Health and Environmental Management Association and Chemical
Laboratory Operations, Michigan Technological
University, Houghton, Michigan 49931, United
States
| | - Michael B. Blayney
- Research
Safety, Northwestern University, Evanston, Illinois 60208, United States
| | - Lusiana Galindo
- Research
Safety, Northwestern University, Chicago, Illinois 60611, United States
| | - Robert Foreman
- Research
Safety, Northwestern University, Chicago, Illinois 60611, United States
| | - Marina Zelivyanskaya
- Research
Safety, Northwestern University, Chicago, Illinois 60611, United States
| | - Marc Reid
- Department
of Pure & Applied Chemistry, University
of Strathclyde, Glasgow G1 1XL, United Kingdom
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136
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Sleator RD, Darby S, Giltinan A, Smith N. COVID-19: in the absence of vaccination - 'mask the nation'. Future Microbiol 2020; 15:963-966. [PMID: 32677846 PMCID: PMC7367512 DOI: 10.2217/fmb-2020-0112] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Roy D Sleator
- Department of Biological Sciences, Cork Institute of Technology, Bishopstown, Cork, Ireland
| | - Steven Darby
- Centre for Advanced Photonics & Process Analysis, Cork Institute of Technology, Bishopstown, Cork, Ireland
| | - Alan Giltinan
- Blackrock Castle Observatory, Cork Institute of Technology, Bishopstown, Cork, Ireland
| | - Niall Smith
- Blackrock Castle Observatory, Cork Institute of Technology, Bishopstown, Cork, Ireland
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