Homemade cloth face masks need at least two layers, and preferably three, in order to successfully prevent the dispersal of COVID-19-causing viral droplets from nose and mouth, a new study has indicated.
An infected individual is capable of transmitting the coronavirus infection onto others through viral droplets that are generated while the person coughs, sneezes, or even speaks. However, face masks not only prevent these droplets from travelling a long distance, but they also—to an extent—protect healthy people from inhaling the infectious droplets.
But now, a new study, published in the journal Thorax, has found masks with three layers to be the most effective in preventing the viral droplets from travelling long distances. Single- and double-layer masks, on the other hand, were only observed to work to a certain extent.
The study involved a team of Australian researchers, which compared the effectiveness of single- and double-layer cloth face coverings with a 3-ply surgical face mask in reducing droplet spread. The single-layer covering was made from a folded piece of cotton T-shirt and hair ties, while the double layer covering was made using the sewing method set out by the CDC.
Using a tailored LED lighting system and a high-speed camera, the researchers then filmed the dispersal of airborne droplets produced by a healthy person as the individual spoke, coughed, and sneezed while wearing each type of mask.
The subsequent recordings showed that the 3-ply surgical face mask was the most effective at reducing airborne droplet dispersal. Meanwhile, the single-layer cloth face-covering only reduced the droplet spread to an extent while speaking, and the double-layer covering performed slightly better than single-layer in curbing droplet spread while coughing and sneezing.
While covering certainly plays a role, the researchers added that in general, other factors such as the type of material, their design and fit, and the frequency of washing also contribute to the effectiveness of cloth face masks.
Nevertheless, the study authors insist that homemade cloth masks with at least two layers are preferable to single-layer masks, while adding: “Guidelines on homemade cloth masks should stipulate multiple layers. There is a need for more evidence to inform safer cloth mask design, and countries should ensure adequate manufacturing or procurement of surgical masks.”
The complete findings of this study were published in the journal Thorax earlier this week and can be accessed here.
(With inputs from IANS)
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