Scientists are now reporting that wearing two face coverings can almost double the filtration efficiency of SARS-CoV-2-sized particles, preventing them from reaching the wearer’s nose and mouth and causing Covid-19. many by adding layers of fabric but eliminating any gaps or ill-fitting areas of a mask, according to the study published in JAMA Internal Medicine. “Medical procedure masks are designed to have very good filtration potential depending on their material, but the way they adapt to our faces is not perfect,” said Emily Sickbert-Bennett, associate professor of infectious diseases at the University of North Carolina (UNC) School of Medicine and lead author of the range of masks, the researchers worked with James Samet and his colleagues at the EPA Human Studies Facility on campus of UNC-Chapel Hill where they filled a 10-by-10-foot stainless steel exposure chamber with small particulate aerosol sprays, and asked the researchers to wear coveralls to test their effectiveness at prevent particles from entering their breathing space.
By measuring the concentration of particles in the breathing space under the mask relative to that in the chamber, the researchers determined the FFE. “We also asked the researchers in the chamber to undergo a series of range of motion activities to simulate the typical movements a person can throughout the day, bending at the waist, talking and looking left, right, top to bottom, “said Phillip Clapp, inhalation toxicologist at UNC School of Medicine. mask differs from person to person, due to the unique fit of each person’s face and mask. In general, an intervention mask without changing the fit is about 40-60% effective in preventing the entry of particles the size of Covid-19. A cloth mask is about 40% effective. When layered over procedural masks, cloth masks improve the fit by eliminating gaps and keeping the procedural mask closer to the face, consistently covering the nose and mouth. , FFE improved by 16 percent. “We have found that wearing two loosely fitting masks will not give you the filtration advantage of a properly fitted procedural mask,” Sickbert-Bennett said.