With face masks becoming mandatory for some in Victoria, people have jumped to make their own, with many using any material at their disposal. From socks to old shirts, almost anything can be turned into a reusable mask. New research shows, however, that using more layers — at least three — is crucial for a mask to be effective.
A new study from researchers at the University of New South Wales (UNSW) has shown homemade masks should have three layers, but even two layers would be a major improvement from just a single one.
The study evaluated recommendations provided by the Centers for Disease Control and Prevention (CDC), the US’s peak health institute. In those videos, the CDC proposed two methods of making your own mask — a one-layer no-sew method using an old shirt, and a two-layer method using sewing.
Through testing droplet spread when a person was speaking, coughing or sneezing, it found a surgical mask worked best at limiting spread, but a two-layer mask wasn’t too far behind.
A single-layer homemade mask did an acceptable job, except for when a person sneezed through it. The findings also concluded that a single-layer mask was still better than having no mask at all.
Prateek Bahl, a PhD student at UNSW who worked on the paper, explained the original CDC video had different instructions, but it’s no-sew method now contained multiple layers, making it more effective.
Researchers also pointed out a study that showed a 12-layered cotton mask was as effective as a surgical mask, but a single-layered cloth mask was not protective against beta-coronaviruses. The lesson here is the more layers, the better.
“Based on the existing research, a cloth mask with at least three layers is preferable,” Bahl said in an email to Lifehacker Australia.
Use different materials for the layers where possible
While you could conceivably make one with three cotton layers, Bahl added it would be more effective if you used a layer of polyester or nylon as an out layer over the cotton.
“The inner layer should be made of cotton/linen and the outer layer should be made of polyester/nylon. The middle layer/layers can either be the blends like a mixture of cotton/polyester or pure nylon or polyester,” Bahl said.
“But, even if you are using the same material for all layers, at least three layers should be used.”
Since many of us are making our face masks given the high demand for them in Australia right now, it’s an important rule to remember. If you’re using the sock method, as we wrote about earlier this week, add another sock to it, or insert a few materials into it to make it more effective.
Another important thing to remember is regular washing of your mask. After a single daily use, Bahl recommends washing it because you never know what it’s come in contact with while you were out.
“It is essential to always use a clean mask and hence it should be washed daily after use,” Bahl said.
“Every time you go out, there is a possibility of it getting contaminated.”