As a countermeasure against the new coronavirus, the movement to wear double masks is spreading in Japan and overseas.
It has become more prominent in the city, including the one worn by President Biden of the United States, Taro Kono, Minister of State of Japan, and Yuriko Koike, the governor of Tokyo. What is the effect of the “double mask”?
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The Centers for Disease Control and Prevention (CDC) recently announced research results that a better fit of the mask would significantly reduce the risk of infection. As a method of eliminating gaps and enhancing the effect, we introduced the method of layering cloth on a non-woven mask.
In one of the experiments, the emission side and the receiver were set, and when one piece of non-woven fabric was normally worn on both sides, the number of particles exposed to the receiver was reduced by 84.3%. In both cases, when cloth was layered on non-woven fabric and doubled, it decreased by 96.4%. Even with a single piece of non-woven fabric, the effect can be enhanced by tying the ear straps at both ends of the mask to eliminate gaps.
How do Japanese experts see it? Associate Professor Kazushige Onishi (Environmental Medicine / Public Health) of St. Luke’s International University graduate school warns that “just wearing a double mask does not have a great effect.” In an experiment with the cooperation of 225 people, there were many gaps just by wearing a mask, and 126 people had a “leakage rate” of 100%.
If the mask is brought into close contact with the face by hand, the leakage rate will be reduced by about 20%, but it is estimated that the effect of stacking cloth from above will be “less than half that of holding it by hand.” “The larger the size of the cloth, the weaker the pressing force,” he said.
Makoto Tsubokura, a team leader at RIKEN and a professor at Kobe University, who is also a representative of research on virus droplet infections by supercomputers such as Tomitake, said, for example, about two layers of non-woven fabric, It becomes easy to leak. ” Emphasizing that it is important to keep it in close contact with the face, “Double masks can be stuffy. Not only masks, but also ventilation and other comprehensive measures should be considered without load. When walking outside, everyone talks. You can use cloth or urethane in a space that doesn’t exist, and you can wear cloth on a non-woven fabric at a dense meeting, depending on the TPO. “
First of all, it seems important to be careful to fit your face tightly.[Naoto Sawada, Hayato Kubo]
○… Various voices were raised from the people in the city who actually wear double masks. A woman (in her 60s) who wore a non-woven fabric on the outside and a cloth on the inside said, “The non-woven fabric becomes itchy and rough when it touches the skin. .. A male office worker in his thirties who wore a urethane mask on the inside also said, “I wonder if the non-woven fabric has fluffy fibers in my mouth, which makes my throat hurt.” On top of that, he confessed, “The non-woven fabric is in a visible position. The mask police are scared.”
A male office worker in his 50s wore a sports brand cloth on the inside and said, “I heard that it is effective to double it. When I get on the train, I wear non-woven fabric and double it, and when I exercise, I use only cloth. I use it properly. “