Quarantine during the current COVID-19 pandemic has provided many with the time and opportunity to get in touch with their creative sides. With the price of face masks increasing, and the need to wear a mask becoming mandatory, individuals have been making their own face masks or coverings.
A recent study completed by Onur Aydin and colleagues at the University of Illinois at Urbana-Champaign tested the efficiency of home-made masks at preventing the spread of COVID-19. COVID-19 is a respiratory infection similar to influenza, SARS-1, and MERS. Those three respiratory infections are known to spread through droplets, aerosols, and contact. It is not confidently understood how COVID-19 spreads, but it is known that virus particles are released when an individual infected with COVID-19 sneezes, coughs, or even speaks. Medical masks have recently shown to be effective in reducing the spread.
However, medical masks are not easily accessible to everyone, so many must use household fabrics that are repurposed as face coverings. Therefore, this study tested the performance of 11 household fabrics for their ability to block “large, high-velocity droplets” and also “assessed breathability, (air permeability), texture, fiber composition, and water absorption properties of the fabric.” The fabrics tested included woven, knit, napped, cotton, polyester, polyamide, and silk. A method was developed to “quantify the effectiveness of fabrics at blocking large droplets containing 100 diameter nanoparticles (nm) which would mimic the virus, specifically in terms of the size of the particles. However, the procedure to test each of the factors were varied.
There are two key elements for face coverings: “breathability and droplet blocking efficiency.” Unlike fit-tested respirators, simple cloth or medical masks cannot tightly seal any gaps to the contours of an individual’s face. Consequently, a large portion of the air released when breathing, coughing, or sneezing escapes through the gaps. With low breathability, comes more leakage , which gives the individual a false sense of protection, even when the material of the covering may be efficient at blocking droplets.
The study found that household fabrics did indeed “have considerable efficiency at blocking high-velocity droplets, even as a single layer.” With multiple layers, highly permeable fabrics, similar to that of a t-shirt, can even efficiently block particles at the same efficiency of a medical mask.
It is important to note that the study did not consider how the masks/face coverings should be produced, how they should be worn, and how they should be used/decontaminated. Many masks that are homemade are reusable. Hence, proper measures should be taken to use the masks appropriately to ensure they are clean.
The study concluded that “during pandemics and mask shortages, home-made face coverings with multiple layers can be effective against transmission of respiratory infection through droplets.” Moreover, the study made clear that if all individuals wear a mask, “supported by proper education and training of mask making and appropriate usage” it can be an effective strategy to reduce disease transmission, specifically when following social distancing measures.