Making sure a mask fits snugly and use of two masks is likely to significantly reduce a person’s exposure to COVID-19, according to studies by U.S. Centers of Disease Control and Prevention researchers.
In lab tests, they found wearing a cloth mask over a three-ply medical mask, and knotting the ear loops of the medical mask so it fits snugly and then tucking the excess material close to the face, helped reduce exposure to potentially infected aerosols by over 90%.
In one experiment, an unknotted medical mask alone blocked 42% of particles from a simulated cough, and the cloth mask alone blocked 44%. The double mask combination blocked 92% of the cough particles, they reported in CDC‘s Morbidity and Mortality Weekly Report.
In an #AskReuters Twitter Chat, Dr. Charles Holmes, director of the Center for Innovation in Global Health at Georgetown University, recommended wearing the most effective mask on the inside.