Study Measures Effectiveness Of Vacuum Bags As Face Mask Material
A recent study notes that while there are many online resources which help people make their own masks, there is little scientific evidence on what are the most suitable materials to use. Here is the latest on mask materials tested that include using the material from a vacuum bag.
Alternative Mask Materials Study
A recent research news release from the University of Cambridge reports the publication of a new study in the journal BMJ Open that while many alternative materials people are using to make their own homemade masks are effective in filtering the air we breathe in and out, there are caveats that need addressing.
“Fabric masks have become a new necessity for many of us since the start of the COVID-19 pandemic,” said first author Eugenia O’Kelly from Cambridge’s Department of Engineering. “In the early stages of the pandemic, when N95 masks were in extremely short supply, many sewers and makers started making their own fabric masks, meeting the demands that couldn’t be met by supply chains, or to provide a more affordable option.”
The difference between this study from previous mask studies is the focus on alternative mask materials used by the public for making homemade masks and their actual efficacy when users exhale forcefully or cough rather than just breathing normally.
“There was an initial panic around PPE and other types of face masks, and how effective they were,” said O’Kelly. “As an engineer, I wanted to learn more about them, how well different materials worked under different conditions, and what made for the most effective fit.”
According to the news release:
“… O’Kelly and her colleagues built an apparatus consisting of sections of tubing, with a fabric sample in the middle. Aerosolized particles were generated at one end of the apparatus, and their levels were measured before and after they passed through the fabric sample at a speed similar to coughing. The researchers also tested how well each fabric performed in terms of breathing resistance, based on qualitative feedback from users.”
How Mask Materials Compared
What the researchers found was that:
• Compared to homemade masks, the N95 mask works best overall for both filtering, fit and breathability.
• A reusable HEPA vacuum bag exceeded the N95 performance in some respects.
• Most of the fabrics used for non-clinical face masks are effective at filtering ultrafine particles, including material from jeans.
• Homemade masks made of multiple layers of fabric and added support showed a significant improvement in performance, but were more difficult to breathe through than an N95 mask.
• Homemade masks made of fabrics worked well while damp and worked sufficiently after one laundry cycle. However, repeated washing degrades the fabrics and raises the risk of inhaling fibers that could be harmful.
• Single-use and reusable vacuum bags were effective at blocking particles, but the researchers caution that the single-use bags should not be used in face masks, because they fall apart when cut, and may contain component materials that are unsafe to inhale.
“It’s a matter of finding the right balance—we want the materials to be effective at filtering particles, but we also need to know they don’t put users at risk of inhaling fibers or lint, which can be harmful,” said O’Kelly.
While the study did not analyze how well homemade masks perform regarding the fit of the masks against the face with respect to air leakage during use, the authors of the study believe that their results may prove useful to those who make their own masks.
“We’ve shown that in an emergency situation where N95 masks are not available, such as in the early days of this pandemic, fabric masks are surprisingly effective at filtering particles which may contain viruses, even at high speeds,” states O’Kelly.
For more about facemask protection, the news release recommends clicking on this link for more recommendations from the Engineering Task Force at the University of Cambridge.
Timothy Boyer has a Ph.D. in Molecular and Cellular Biology from the University of Arizona. For 20+ years he has been employed as a freelance health and science writer. Today, with an eye on the latest news, Timothy continues writing about science with a focus on what you need to know for healthier living. For continual updates about health, you can also follow Timothy on Twitter at TimBoyerWrites.
Image Source: Courtesy of Flockine from Pixabay
“Study measures effectiveness of different face mask materials when coughing” University of Cambridge Research News 29 Oct. 2020.
“Ability of fabric face mask materials to filter ultrafine particles at coughing velocity” O'Kelly E, Pirog S, Ward J, et al., BMJ Open 2020;10:e039424. doi: 10.1136/bmjopen-2020-039424.