Coronavirus: New research shows homemade face masks need three layers
Homemade masks need at least two layers of material — but preferably three — to stop the spread of COVID-19.
Homemade face masks need at least two layers of material — but preferably three — to stop the spread of COVID-19, new research has revealed.
Raina MacIntyre, head of biosecurity at the Kirby Institute, co-authored the new research which found homemade masks should have three layers to effectively prevent viral droplets escaping from the nose and mouth.
The study tested how well cloth coverings with one and two layers compared with a surgical face mask to stop viral droplet spread when a person talked, coughed and sneezed.
It used the US Centres for Disease Control and Prevention suggested “no-sew” method to make a one-layer face covering from a cut-out T-shirt, and a sewing method to create a two-layer mask.
A high-speed camera and tailored LED lighting system was used to capture a series of images showing viral droplet spread under the three scenarios.
A three-ply surgical mask was found to be the most effective. Pictures show only a few droplets were able to escape.
But study revealed even a single covering was better than nothing, as it could reduce droplet spread when speaking.
The study suggested guidelines on how to make a mask should “stipulate multiple layers (at least three)”.
The Australian researchers who led the study said there was “little or no” evidence on how well different types of material work.
They noted multiple factors make masks better or worse at stopping the spread of droplets, including the number of layers, how they are arranged and how often the mask is washed.
People in Mitchell Shire, Victoria, and greater Melbourne were told to “mask up” from midnight on Wednesday or risk a $200 fine, prompting Melburnians to buy sewing machines, elastic and fabric to make their own face coverings.
NSW Premier Gladys Berejiklian on Thursday stopped short of enforcing the use of face masks, but said “if you can’t guarantee social distancing … you should be wearing a mask”.
Speaking on 2GB, NSW Transport Minister Andrew Constance said the state could harden its stance in the future but for now people should “consider” wearing a face covering.
NSW Labor has called for masks to be made mandatory on Sydney’s public transport system.
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