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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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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...

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... 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. ...

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... The relevant research is extremely limited. For example, in Sven Fikenzer's and Davies's studies, ventilation and cardiopulmonary exercise capacity were reduced by surgical masks in 9and 12 healthy males, respectively [5,6]. The studies published so far have each recruited only a small number of male subjects with a relatively large age span; however, age and gender differences are important factors affecting exercise and cardiopulmonary function [7,8]. ...
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Objective: To explore the impacts of surgical mask in normal subjects on cardiopulmonary function and muscle performance under different motor load and gender differences. Design: Randomized crossover trial. Setting: The Fifth Affiliated Hospital of Guangzhou Medical University, June 16th to December 30th, 2020. Participants: Thirty-one college students (age: male 21.27 ± 1.22 years; female 21.31 ± 0.79 years) were recruited and randomly allocated in two groups. Interventions: Group 1 first received CPET in the mask-on condition followed by 48 h of washout, and then received CPET in the mask-off condition. Group 2 first received CPET in the mask-off condition followed by 48 h of washout, then received CPET in the mask-on condition. The sEMG data were simultaneously collected. Main outcome measures: The primary outcome was maximum oxygen uptake (VO2 max) from CPET, which was performed on a cycle ergometer-this is the most important parameter associated with an individual's physical conditioning. The secondary parameters included parameters reflecting exercise tolerance and heart function (oxygen uptake, anaerobic valve, maximum oxygen pulse, heart rate reserve), parameters reflecting ventilation function (respiration reserve, ventilation volume, tidal volume, breathing frequency), parameters reflecting gas exchange (end-tidal oxygen and carbon dioxide partial pressure, oxygen equivalent, carbon dioxide equivalent, and the relationship between dead space and tidal volume) and parameters reflecting skeletal muscle function [oxygen uptake, anaerobic valve, work efficiency, and EMG parameters including root mean square (RMS)]. Results: Comparing the mask-on and mask-off condition, wearing surgical mask had some negative effects on VO2/kg (peak) and ventilation (peak) in both male and female health subjects [VO2/kg (peak): 28.65 ± 3.53 vs 33.22 ± 4.31 (P = 0.001) and 22.54 ± 3.87 vs 26.61 ± 4.03 (P < 0.001) ml/min/kg in male and female respectively; ventilation (peak): 71.59 ± 16.83 vs 82.02 ± 17.01 (P = 0.015) and 42.46 ± 10.09 vs 53.95 ± 10.33 (P < 0.001) liter in male and female respectively], although, based on self-rated scales, there was no difference in subjective feelings when comparing the mask-off and mask-on condition. Wearing surgical masks showed greater lower limb muscle activity just in male subjects [mean RMS of vastus medialis (load): 65.36 ± 15.15 vs 76.46 ± 19.04 μV, P = 0.031]. Moreover, wearing surgical masks produced a greater decrease in △tidal volume (VTpeak) during intensive exercises phase in male subjects than in female [male - 0.80 ± 0.15 vs female - 0.62 ± 0.11 l P = 0.001]. Conclusions: Wearing medical/surgical mask showed a negative impact on the ventilation function in young healthy subjects during CPET, especially in high-intensity phase. Moreover, some negative effects were found both in ventilation and lower limb muscle actives in male young subjects during mask-on condition. Future studies should focus on the subjects with cardiopulmonary diseases to explore the effect of wearing mask. Trial registration: Chinese Clinical Trial Registry ( ChiCTR2000033449 ).
... Masks can block the transmission of droplets or aerosols from coughers and protect wearers from inhaling droplets or aerosols from nearby coughers. Thus, masks can inhibit the spread of diseases that are transmitted by droplets or aerosols (Brienen et al., 2010;Lai et al., 2012;Davies et al., 2013). Chu et al. (2020)'s meta-analysis of 39 studies found that, on average across social settings, people wearing masks have a 3.1% chance of being infected, while those without masks have a 17.4% chance of being infected with SARS-CoV-2 and the betacorona viruses that cause severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). ...
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... They could not offer the same blocking efficiency as N95 respirators but were expected to decrease the exposure of uninfected wearers to reduce the risk of viral infection [23][24][25]. On the other hand, several raw materials were evaluated as alternatives to non-woven fabric filters [24,26,27], and cloth masks were revealed to provide only limited protection [28]. However, the performance of 3D-printed masks has never been evaluated in detail [17,20]. ...
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Facemasks are one of the most effective and low-cost prophylactics for COVID-19. In the spring 2020, when a severe shortage of facemasks occurred worldwide, various types of 3D-printed masks were designed and proposed. However, the protective effects conferred by most of these masks were not experimentally evaluated. Here, we provide a new simple design of 3D-printed mask and evaluate its protective effect in a viral filtration test using a human head mannequin. The developed mask can be constructed with a low-cost 3D printer, with an approximate production cost of US $4. This mask has three parts: the main part, wearing parts, and a piece of non-woven fabric filter. The volume of the filter, which needs to be changed daily, was reduced to approximately 1/10 of that of commercially available surgical masks used in this study. The developed mask is fabricated from polylactic acid, a biodegradable plastic, and its surface contour contacting the face may be adjusted after softening the material with hot water at 60–80°C. The viral filtration efficiency of the developed mask was found to be over 80%. This performance is better than that of commercially available facemasks, such as surgical masks and cloth masks, and equal to those of KN95 and KF94.
... 6,7 Other research teams had face mask-wearing participants conduct exercises, such as breathing, moving the head, and bending down at the torso, before testing the particles. 1,9 This method allows for a calculation of how many particles escape the face mask; large differences in concentration imply small gaps and leakage. O'Kelly et al. 7 claimed their calculation was a reliable method to validate the fit of the face mask. ...
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... Therefore, fabric mask performance was evaluated in this study based on their filtration efficiency. To estimate the value of e, we have reviewed many studies about face masks and their efficacy in reducing COVID-19 transmission [46][47][48][49][50]. We estimated the value of e from studies of low risk of bias which studied cloth masks similar to face masks available and used in NWS. ...
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Syria has experienced armed conflict since 2011, and the provision of health care has been severely compromised due to the hostilities. At the time of writing, Northwest Syria (NWS) was outside governmental control and faced the challenges of the COVID-19 outbreak. Since the emergence of this disease, several studies have looked at the dynamics of COVID-19 transmission, predicted its progression, and determined the impact of different preventive measures. While most of these studies’ settings were in stable contexts, this study investigated the progression of the COVID-19 pandemic in Northwest Syria, a conflict-affected region, for nine months (from July 2020 to March 2021) using the Suspected-Infected-Removed (SIR) model. We adjusted the SIR model to study the impact of wearing facial masks on the outbreak dynamics and progression. Based on available data and using the basic and adjusted SIR models, we estimated the value of the basic reproduction number (R0), which provides an initial prediction of disease progression. Using the basic SIR model, the estimated R0 for the first wave of SARS-CoV-2 in Northwest Syria was 2.38. The resulting figures were overestimated in comparison with the reported numbers and data on the COVID-19 pandemic. However, the results were significantly reasonable when we adjusted the model for a preventive measure (in this case, wearing face masks). Face masks, the most available preventive measure to be applied in emergency and conflict settings, remarkably affect the outbreak dynamics and may play a key role in controlling and limiting the spread of COVID-19. The novelty of the study is provided by simulating the progress of the COVID-19 outbreak in conflict settings, as it is the first study to predict the dynamics of COVID-19 disease in NWS by adjusting for face-mask-wearing as a preventive measure to explore its impact on outbreak dynamics.
... Globally, disposable medical masks are used millions of times a day, and yet and environmental impacts of this product are scarcely known. There are a limited number of studies that assess the environmental sustainability of face masks (Akarsu et al. 2021;Allison et al. 2020;Davies et al. 2013;Fadare and Okoffo 2020;Klemeš et al. 2020;Lee et al. 2021;Schmutz et al. 2020;van Straten et al. 2021). Some of the papers compared the environmental impacts of the selected type of masks such as reusable masks and disposable medical masks (Davies et al. 2013;Lee et al. 2021;Schmutz et al. 2020;van Straten et al. 2021). ...
... There are a limited number of studies that assess the environmental sustainability of face masks (Akarsu et al. 2021;Allison et al. 2020;Davies et al. 2013;Fadare and Okoffo 2020;Klemeš et al. 2020;Lee et al. 2021;Schmutz et al. 2020;van Straten et al. 2021). Some of the papers compared the environmental impacts of the selected type of masks such as reusable masks and disposable medical masks (Davies et al. 2013;Lee et al. 2021;Schmutz et al. 2020;van Straten et al. 2021). The scope and selected mask type vary across the papers. ...
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A massive increase in the use and production of masks worldwide has been seen in the current COVID-19 pandemic, which has contributed to reducing the transmission of the virus globally. This paper aims to evaluate the life cycle environmental impacts of disposable medical masks to identify the life cycle stages that cause the highest impact on the environment. A further goal is to estimate the total environmental impacts at the global level in 2020. The inventory data was constructed directly from the industry. The system boundary of the study is from cradle to grave comprising raw material extraction and processing, production, packaging, distribution, use, and disposal as well as transport and waste management along the supply chain. Eleven environmental impacts have been estimated. The results suggest that the global warming potential of a disposable medical mask is 0.02 g CO2-eq. for which the main contributor is the raw material supply (40.5%) followed by the packaging (30.0%) and production (15.5%). Sensitivity analysis was carried out to test the environmental impacts. In total, 52 billion disposable medical masks used worldwide consumes 22 TJ of energy in 2020. The global warming potential of disposable medical masks supplied in a year of the COVID-19 pandemic is 1.1 Mt CO2 eq. This paper assessed the hotspots in the medical mask. The findings of this study will be of interest to policymakers, global mask manufacturers, and users, allowing them to make more informed decisions about the medical mask industry. Graphical abstract
... Biermann et al. 15 suggested that charge exchange between the charges of the mask and the ions of the solutions could take place; this could also be due to an increase in the charge mobility caused by a higher electrical conductivity of the solution 16 . The in-situ treatment has a considerable effect on the electrostatic potential and the FE (Figs. 4,5). This could be induced by the spraying while exposing the pores during folding, and by the liquid being pushed into the mask during the compression phase, inducing a full coating of the mask fibers by the solution/body fluid. ...
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After the spread of COVID-19, surgical masks became highly recommended to the public. They tend to be handled and used multiple times, which may impact their performance. To evaluate this risk, surgical masks of Type IIR were submitted to four simulated treatments: folding, ageing with artificial saliva or sweat and washing cycles. The air permeability, mechanical integrity, electrostatic potential, and filtration efficiency (FE) of the masks were measured to quantify possible degradation. Overall, air permeability and mechanical integrity were not affected, except after washing, which slightly degraded the filtering layers. Electrostatic potential and FE showed a strong correlation, highlighting the role of electrostatic charges on small particle filtration. A slight decrease in FE for 100 nm particles was found, from 74.4% for the reference masks to 70.6% for the mask treated in saliva for 8 h. A strong effect was observed for washed masks, resulting in FE of 46.9% (± 9.5%), comparable to that of a control group with no electrostatic charges. A dry store and reuse strategy could thus be envisaged for the public if safety in terms of viral and bacterial charge is ensured, whereas washing strongly impacts FE and is not recommended.
... As such these types of face coverings are recommended for use by the public under low-risk, non-professional applications [22] in conjunction with multiple health and safety precautions that include maintaining physical distancing, frequent hand hygiene, and adherence to local health advice and restrictions including indoor building capacity limits, participation in COVID-19 testing programs, contact tracing and self-isolation, and community vaccination programs. Prior to the pandemic there were limited studies exploring performance characteristics of common commercial fabrics that the public could source and use in the construction of home-made cloth masks as alternatives to commercial PPE [23][24][25][26][27][28][29][30][31]. Notable early studies examined material filtration efficiencies for bacteria and virus-sized particles [23,24] and quantitative fit testing of constructed cloth masks that focused on the protection of the mask wearer [24][25][26]. ...
... Prior to the pandemic there were limited studies exploring performance characteristics of common commercial fabrics that the public could source and use in the construction of home-made cloth masks as alternatives to commercial PPE [23][24][25][26][27][28][29][30][31]. Notable early studies examined material filtration efficiencies for bacteria and virus-sized particles [23,24] and quantitative fit testing of constructed cloth masks that focused on the protection of the mask wearer [24][25][26]. Since the start of the pandemic, more than 40 studies have been published documenting fabric filtration performance and cloth mask filtration efficiency. ...
... Prior to the pandemic there were limited studies exploring performance characteristics of common commercial fabrics that the public could source and use in the construction of home-made cloth masks as alternatives to commercial PPE [23][24][25][26][27][28][29][30][31]. Notable early studies examined material filtration efficiencies for bacteria and virus-sized particles [23,24] and quantitative fit testing of constructed cloth masks that focused on the protection of the mask wearer [24][25][26]. Since the start of the pandemic, more than 40 studies have been published documenting fabric filtration performance and cloth mask filtration efficiency. ...
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The objective of this study was to characterize commercially-available cotton fabrics to determine their suitability as materials for construction of cloth masks for personal and public use to reduce infectious disease spread. The study focused on cottons because of their widespread availability, moderate performance and they are recommended for inclusion in home-made masks by international health authorities. Fifty-two cottons were analyzed by electron microscopy to determine fabric characteristics and fabric weights. Sixteen fabrics were selected to test for breathability and to construct 2-ply cotton masks of a standard design to use in quantitative fit testing on a human participant. Cotton mask fitted filtration efficiencies (FFEs) for 0.02–1 μm ambient and aerosolized sodium chloride particles ranged from 40 to 66% compared with the mean medical mask FFE of 55±2%. Pressure differentials across 2-ply materials ranged from 0.57 to > 12 mm H 2 O/cm ² on samples of equal surface area with 6 of 16 materials exceeding the recommended medical mask limit. Models were calibrated to predict 2-ply cotton mask FFEs and differential pressures for each fabric based on pore characteristics and fabric weight. Models indicated cotton fabrics from 6 of 9 consumer categories can produce cloth masks with adequate breathability and FFEs equivalent to a medical mask: T-shirt, fashion fabric, mass-market quilting cotton, home décor fabric, bed sheets and high-quality quilting cotton. Masks from one cloth mask and the medical mask were re-tested with a mask fitter to distinguish filtration from leakage. The fabric and medical masks had 3.7% and 41.8% leakage, respectively. These results indicate a well fitted 2-ply cotton mask with overhead ties can perform similarly to a disposable 3-ply medical mask on ear loops due primarily to the superior fit of the cloth mask which compensates for its lower material filtration efficiency.
... But keep in mind, masks with different basic ingredients will provide different protection effectiveness. In general, cloth masks frequently used by the public have a filtration rate of between 49% and 86% for exhaled 0.02 m particles, while medical masks have a filtration rate of 89% for the same particles (22). Point 18, evidence indicates that COVID-19 spreads between individuals by direct, indirect (contaminated objects or surfaces), or close contact with persons infected with oral and nasal secretions. ...
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Currently, all countries are panicking due to the COVID-19 pandemic. This disease must be a matter of concern because the transmission process is so fast that it has an impact on increasing morbidity and mortality rates. One thing that is very important is to measure the level of public knowledge regarding COVID-19 so that early disease prevention can be carried out. It is hoped that by knowing the knowledge of the merchant community, interventions can be planned that can be carried out to increase community knowledge on an ongoing basis. This topic is something that has just been done to see the relationship between individual characteristics and knowledge about COVID-19, especially the traders’ community because the market is one of the clusters in the transmission of COVID-19. The research objective was to measure the level of public knowledge about COVID-19 and also to see the relationship between individual sociodemographic characteristics and public knowledge about COVID-19 disease. This type of research is a type of quantitative research with cross sectional design on the community of traders in the Ganesha housing market, Semarang City. The samples who were determined by saturated sampling technique and given informed consent to respondents. The data collection method in this research is by distributing questionnaires to respondents, observing and interviewing the traders’ community. Data analysis used univariate analysis to describe the characteristics of respondents, then cross tab analysis was carried out with an associative test (Chi-square, p> 0.05) to determine the relationship between individual characteristics and the knowledge of the traders’ community about COVID-19 disease. The results showed that the sociodemographic characteristics (gender, age, and education level) were not related to the knowledge of the traders’ community about COVID-19 disease. The knowledge of the traders’ community in general is in the high category at 82%. This research is useful for increasing public knowledge, and providing a sense of awareness of the COVID-19 pandemic, so that it can prevent the transmission of COVID-19. This research was conducted as an effort to break the chain of transmission of COVID-19 so as to reduce morbidity due to COVID-19. The results of this study have implications for determining the type of socialization and training activities appropriate to the level of knowledge of the merchant community. It is important to carry out further research on the interventions of various health education media in accordance with the characteristics of the community as an effort to increase public knowledge in an effort to prevent COVID-19. Keywords: