A good mask is “the most important defense we have” against COVID, says aerosol expert Kimberly Prather, an atmospheric chemist at the University of California, San Diego.
There are a number of national standards for respirator quality. The U.S. gold standard, N95s, are certified by the CDC’s National Institute for Occupational Safety and Health (NIOSH). And the Occupational Safety and Health Administration (OSHA) sets standards for how they have to fit people in work settings (such as in hospitals). But there is no official standard for N95 use by the general public.
An issue with commercially available high-filtration masks is that they may not come from reputable suppliers. The CDC’s Web site warns that about 60 percent of KN95 respirators available in the U.S. are counterfeit. To find ones that are legitimate, Prather recommends the Web site Project N95. Masks can also be ordered directly from suppliers such as Bona Fide Masks, which sells KN95s made by Powecom. “That’s the one people swear by,” Prather says. They cost around $1 each. DemeTECH sells N95s for around $4 apiece, as well as other types of masks.
Pictured from left: The K95, the 3M N95, the Moldex N95 and the KF94 Bluna Facefit
In the absence of more specific guidance from health authorities such as the CDC as to which brands of respirators and other masks provide the best protection, some skilled amateurs have stepped in to fill the gap. Aaron Collins, aka “Mask Nerd,” is a mechanical engineer at Seagate Technology with a background in aerosol science. In his free time, he makes YouTube videos in which he tests and reviews high-filtration masks made by various manufacturers. Collins says he does not earn any money from mask manufacturers or his videos themselves—he considers them a service and wants them to be objective.
“To me, the minimum I want to see people wear is a KN95 or KF94 with the Delta variant,” Collins says. “I don’t think surgical masks are good enough anymore, and we should’ve gotten rid of cloth masks last summer—they’re not even in the spectrum” of good filtration. (To be clear, some studies have found that surgical and cloth masks can provide at least some protection against COVID. A recent large, randomized study in Bangladesh found that surgical masks significantly lowered the risk of infection; cloth masks did not have a measurable benefit, although other studies suggest they provide some protection.)
Source: Scientific American