ASOURCE Navi

The second summer of the corona misfortune is approaching. Temperatures are expected to be higher than normal this summer. While the corona vaccination is slow, it is essential to wear a mask to prevent corona infection, but in the summer, the mask tends to stick to the mouth due to sweating, which tends to increase breathing difficulty. Under these circumstances, the Centers for Disease Control and Prevention (CDC) in the United States has introduced a "knot and tuck mask" that makes it easy to breathe without touching the mouth and mask. Virus exposure also appears to be significantly reduced due to the tighter fit of the mask on the wearer's face and reduced edge gaps.

The method of wearing a non-woven mask, “Knot & Tuck Mask”, which the CDC has recently released on its official website, etc., first folds the mask in half horizontally and ties the ear straps on both sides of the mask as close to the mask body as possible. Then, the mask is unfolded and both ends are woven inside to create a three-dimensional shape. Compared to how to wear a normal mask, it fits more firmly on the face, widens the space around the mouth, and makes it easier to breathe. The discomfort caused by the mask sticking to the mouth and skin during the sweating season is considerably eliminated. In addition, since it is possible to breathe air with lower temperature and humidity, the burden on the body is reduced, and it is thought that it will lead to measures against heatstroke. In particular, children are less developed to release heat through their skin than adults.

How to make a knot and tuck mask (CDC official YouTube)

Modified from Brook JT, et al. Morbidity and Mortality Weekly Report (MMWR) February 19, 2021/70(7); 254-257.

The CDC also conducted an experiment to compare the exposure to droplets emitted by an infected person by wearing a regular medical mask and a "knot and tuck mask". As a result, when the source of infection was not wearing a mask and the recipient was not wearing a mask, the number of droplets was reduced by only 7.5% when the recipient was wearing a normal medical mask, assuming "100% exposure". A 64.5% reduction was observed with the “knot and tuck mask”. In other words, it was clarified that the "knot and tuck mask" has the effect of increasing the fit on the face and making it difficult for droplets emitted by infected people to pass through.

This is the US CDC's recommended way to wear it, and it seems to work well for larger or simpler masks.
It seems that the masks distributed in Japan that are originally made in three dimensions, the masks that fit perfectly on the line of the face, and the masks that have extremely short strings when tied may not fit well.

As the heat rises and we need to be vigilant against heat stroke, wearing a mask to prevent corona infection is a hassle, but we want to overcome it by devising ways to wear masks.