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Filtration Efficiency and Pressure Drop Across Materials Tested with Aerosols of Bacillus atrophaeus and Bacteriophage MS2 (30 L/min) a 

Filtration Efficiency and Pressure Drop Across Materials Tested with Aerosols of Bacillus atrophaeus and Bacteriophage MS2 (30 L/min) a 

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Article
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This study examined homemade masks as an alternative to commercial face masks. Several household materials were evaluated for the capacity to block bacterial and viral aerosols. Twenty-one healthy volunteers made their own face masks from cotton t-shirts; the masks were then tested for fit. The number of microorganisms isolated from coughs of healt...

Contexts in source publication

Context 1
... this study, common household materials (see Table 1) were challenged with high concentrations of bacterial and viral aerosols to assess their filtration efficiencies. Surgical masks have been considered the type of mask most likely to be used by the general public, and these were used as a control. ...
Context 2
... the materials tested showed some capability to block the microbial aerosol challenges. In general, the filtration efficiency for bacteriophage MS2 was 10% lower than for B atrophaeus (Table 1). The surgical mask had the highest filtration efficiency when challenged with bacteriophage MS2, followed by the vacuum cleaner bag, but the bag's stiffness and thickness created a high pressure drop across the material, rendering it unsuitable for a face mask. ...

Citations

... It is stressed that the lower protective capabilities of homemade mask are mentioned to prevent that unnecessary risk is taken. [8] A more comprehensive survey of the literature is given in the technical report 1 chapter 3 in section Use of Face Masks in Community Settings of the Community Mitigation Guidelines to Prevent Pandemic Influenza -United States, 2017. [9,10] In the technical report studies about the usefulness of face masks to reduce virus transmission were reviewed. ...
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Respiratory protection for healthy people is currently not recommended by many guidelines. Recently the Czech Republic decided to deviate and made covering mouth and nose mandatory in the public. A short overview about the literature is given, to facilitate a potential reevaluation by the reader.
... Such masks are fairly easily home-fashioned (e.g. Fig. 1A), and can to some extent be considered a useful tool to reduce spread of infection from already infected persons [35]. However they are not usually thought of as an effective form of protection from becoming infected in the first place [21,22,35]. ...
... Fig. 1A), and can to some extent be considered a useful tool to reduce spread of infection from already infected persons [35]. However they are not usually thought of as an effective form of protection from becoming infected in the first place [21,22,35]. For a summary on the role and use of various types of masks, the reader is referred to official World Health Organization (WHO) advice [36]. ...
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Summary. With the current rapid spread of COVID-19, global health systems are increasingly overburdened by the sheer number of people that need diagnosis, isolation and treatment. Shortcomings are evident across the board, from staffing, facilities for rapid and reliable testing to availability of hospital beds and key medical-grade equipment. The scale and breadth of the problem calls for an equally substantive response not only from frontline workers such as medical staff and scientists, but from skilled members of the public who have the time, facilities and knowledge to meaningfully contribute to a consolidated global response. Here, we summarize community-driven approaches based on Free and Open Source scientific and medical Hardware (FOSH) currently being developed and deployed to bolster access to personal protective equipment (PPE), patient treatment and diagnostics.
... In a worst-case scenario, when supplies of RPDs and surgical masks are exhausted, more drastic mitigation strategies may need to be considered, such as wearing common household or workplace materials for barrier protection. 13 Lastly, during a severe pandemic, it is probable that demands on the healthcare system will exceed capacity. Accordingly, nontraditional care settings will be needed to care for those with less severe illness, reserving hospitals for those most ill. ...
... First worn by surgical teams a hundred years ago to prevent bacterial contamination of patient's open wounds, early surgical masks were constructed from layers of cellulose materials, more particularly cotton cellulose (gauze) (Haller and Colwell 1918) and derivatives (Arnold 1938) (see also Belkin 1997). Much more recently, face masks made from cotton fabrics have been tested as alternative respiratory protective equipment against pandemic outbreaks such as influenza (Dato et al. 2006;Davies et al. 2013;Rengasamy et al. 2010). Like respirators, current commercially available surgical face masks include several layers of non-woven fabrics with, frequently, a cellulose inner layer in contact with the wearer's face to improve wearer's comfort. ...
Viral filtration is a critical step in the purification of biologics and in the monitoring of microbiological water quality. Viral filters are also essential protection elements against airborne viral particles. The present review first focuses on cellulose-based filter media currently used for size-exclusion and/or adsorptive filtration of viruses from biopharmaceutical and environmental water samples. Data from spiking studies quantifying the viral filtration performance of cellulosic filters are detailed, i.e., first, the virus reduction capacity of regenerated cellulose hollow fiber filters in the manufacturing process of blood products and, second, the efficiency of virus recovery/concentration from water samples by the viradel (virus adsorption–elution) method using charge modified, electropositive cellulosic filters or conventional electronegative cellulose ester microfilters. Viral analysis of field water samples by the viradel technique is also surveyed. This review then describes cellulose-based filter media used in individual protection equipment against airborne viral pathogens, presenting innovative filtration media with virucidal properties. Some pros and cons of cellulosic viral filters and perspectives for cellulose-based materials in viral filtration are underlined in the review.
... Milton et al. (2013) showed that the surgical masks can remove 96% of coarse influenza virus aerosols (>5 lm) but only 55% of fine influenza virus aerosols (≤5 lm). Davies et al. (2013) further compared the surgical and homemade mask and found that the surgical mask was three times more effective in blocking transmission than the homemade mask. Furthermore, the fit performance of a mask can significantly affect the effectiveness of removing exhaled particles (Mansour and Smaldone, 2013). ...
Article
Unlabelled: Covering a cough can be useful in reducing the transmission of airborne infectious diseases. However, no simple method is available in the literature for predicting the exhaled airflow from a cough with the mouth covered. This investigation used smoke to visualize the airflow exhaled by 16 human subjects. Their mouths were covered by a tissue, a cupped hand, a fist, and an elbow with and without a sleeve. This study then developed simplified models for predicting the airflow on the basis of the smoke visualization data. In addition, this investigation performed numerical simulations to assess the influence of mouth coverings on the receptor's exposure to exhaled particles. It was found that covering a cough with a tissue, a cupped hand, or an elbow can significantly reduce the horizontal velocity and cause the particles to move upward with the thermal plumes generated by a human body. In contrast with an uncovered cough, a covered cough or a cough with the head turned away may prevent direct exposure. Practical implications: This study developed simplified models for predicting the exhaled airflow from a cough with the mouth covered. The proposed models can easily be used to investigate the risk of transmission of airborne infectious diseases in enclosed environments.