The Army Times reports:
The best easy-to-find material for a homemade face covering to protect against coronavirus transmission is four-ply microfiber cloth, according to Army researchers at the service’s Combat Capabilities Development Command.
Researchers with the command’s Chemical Biological Center said in a news release that the four-ply microfiber cloth, which can be found in the cleaning section of most big box stores, filters out more than 75 percent of particles.
An N-95 mask, the protective covering in short supply among hospital workers who need it most, is able to filter out 90 percent of particles, they said. Layering a polyester bandanna can filter out about 40 percent of suspended particles, the release added.