Researchers at the US Centers for Disease Control and Prevention have found that wearing two masks at the same time reduces the risk of coronavirus infection in other people and protects the wearer himself with an effectiveness of up to 80-90 percent. An assessment of various ways to protect yourself from infection is reported on the organization's website.
During the experiment, scientists tested several options for wearing masks and how they effectively trap viral particles when coughing. Combinations such as one 3-layer medical procedure mask, one 3-layer sheet mask, and a 3-layer sheet mask covering the medical mask were evaluated. In addition, the effectiveness of retention of aerosols released during breathing was revealed, while such configurations as a double mask or a mask with tied ear loops were also tested (contributes to the tight fit of the mask to the face – approx. “Lenta.ru” ).
Elastomeric headforms were used to simulate coughing and breathing, which played the role of a source of aerosols and their receiver. One head was equipped with a mouthpiece through which aerosols were released. Three 15-minute runs were performed for each mask wearing option.
The results of the first experiment showed that one medical procedure mask without tied loops blocked 42 percent of aerosol particles, and one sheet mask blocked 44.3 percent. The combination of a sheet mask covering the treatment mask (double mask) blocked 92.5 percent of the particles. In the second experiment, a double mask reduced the exposure of a nearby person without a mask by 82.2 percent, and a mask with a tied loop by 69.2 percent.
If the source did not wear a mask and the exposed person wore a double mask, then this combination provided 83 percent protection. In the case of the tied loop, the impact was reduced by 64.5 percent. If both people wear a double mask or a mask with tied loops, then the protection reached 96.4 and 95.9 percent, respectively.
The scientists added that the study's findings have some limitations. First, they cannot be extended to children with small faces or to men with beards. Second, in real-world conditions, the effectiveness of each wearing option may be different.
