Studies have shown that homemade or cloth face masks can be effective at filtering about 50% of virus particles from the air, on average.
While that may not sound like robust protection to some, aerosol experts say that figure goes up as more people wear masks.
“We do know that there’s a lot of different materials and a lot of different masks that give us at least 50% removal effectiveness,” explained Dr. Richard Corsi, Dean of the Maseeh College of Engineering & Computer Science at Portland State University. “That’s pretty good. Right there, that’s a factor of two reduction.”
A group of researchers at Colorado State University have developed a tool for people to determine just how effective their masks are, depending on the materials used.
“We also know that masks are really, really important for reducing emissions from an infector. So if an infector is speaking or coughing, the mask that they’re wearing can remove a lot of particles and it may be, depending on the material, 50, 60, or 70%.”
When you combine the level of protection that each person’s mask provides, that means that when two people are masked and sharing an indoor space, the effective rate of exhaled particles making their way from one person to another is reduced by approximately 75%.
“That’s pretty amazing, and that’s not with N95 masks,” said Dr. Corsi. “When you add those two things together we get a big bang for our buck right off the bat if we had universal mask wearing.”
Adding basic safety protocols on top of that like opening windows to increase ventilation or using HEPA air purifiers for filtration, and indoor spaces can become much safer with a few relatively affordable steps.
