In the absence of medical-grade personal protective equipment (PPE), many of us have turned to homemade cloth masks to help stop the spread of the coronavirus. But increasingly, research has shown that not all masks are created in the same way, and some are totally ineffective. A new video case study produced by Australian researchers shows that for a homemade cloth mask to stop viral transmission, it must have at least two layers of cloth. Indeed, if your mask has only one cloth layer, you can bet for sure it just doesn’t work.
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Homemade cloth face masks
Using an LED lighting system and a high-speed camera, the research team filmed the dispersion of aerosols produced by a subject while talking, coughing, and sneezing. The subject reflected the behavior of a healthy individual without respiratory disease, meaning that the cough and sneezing used the “normal” daily force that an asymptomatic COVID patient could produce.
After reviewing the footage, the team rated the effectiveness of the three cloth masks (as well as a three-layer surgical mask, which was determined to be the most effective option). In general, the correlation between the number of layers of fabric and the effectiveness was strong: the more layers a fabric mask had, the more effective it was at protecting against the spread of droplets. The footage revealed that the single-layer masks barely impeded the spread of the droplets: in that demonstration, the aerosols dispersed through the air with visible ease.
The team noted that the stitching style also had an effect on the result. Masks that were sewn to standards provided by the Centers for Disease Control (CDC) were much more effective than single-layer masks made from cotton T-shirts and hair bands.
So the next time you go out, make sure your DIY mask is up to scratch. Opt for a design that includes a minimum of two layers of fabric (ideally three!) That has been sewn to CDC standards. And for more information on whether his mask keeps him safe, watch Bill Nye try which facial masks work best.
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