The U.S. Centers for Disease Control and Prevention said on February 10 local time that double-layer masks, that is, the use of cloth masks in addition to medical masks, such as disposable surgical masks, can significantly enhance the protection effect.
The researchers found that by wearing two masks, making the face and mask closer together can block 92.5% of potentially infectious particles of COVID-19.
They also found that folding the edges of the mask inward and knotting the drawstring in the ear can improve the protection performance of medical masks by reducing the gap between the mask and the face.
Knotted medical masks block 63% of aerosol air particles that may contain COVID-19, and 42% without a knot masks.
Starting in January 2021, CDC tested a double-layer mask and knotting method to assess its protective performance.
The effectiveness of cloth masks and medical masks can be improved by ensuring that fabric masks and medical masks fit closely with the contour of the face and preventing air and particles from escaping (or rushing into) from the cracks around the edges of the masks.
The study found that when both infected and uninfected people wear double-layer masks, the likelihood of exposure to potentially infectious COVID-19 particles decreased by 96.4 percent.
When both sides wear masks that are knotted and close to their faces, the likelihood of exposure to potentially infectious COVID-19 particles is reduced by 95.9 percent.
Both findings highlight the importance of good fit to maximize mask performance in protecting people from COVID-19.