"I wear mine for a week," said Linsey Marr, a professor of civil and environmental engineering at Virginia Tech, via CNN.
Marr explained that the N95 surgical mask's material and filtration ability won't "degrade unless you physically rub it or poke holes in it," and specified that "you'd have to be in really polluted air...for several days" before particles weaken the mask's effectiveness.
"People have been talking about 40 hours -- I think that's fine. Really, it's going to get gross from your face or the straps will get too loose or maybe break before you're going to lose filtration ability," Marr added.
Erin Bromage, an associate professor of biology at the University of Massachusetts Dartmouth, explained that the masks are designated as "single use" because they are typically categorized as medical masks, so health care workers would need to swap them out more frequently to avoid "cross-contaminating a patient room with equipment that was worn in a room of an infectious person and then moving to the next room and bringing that infection with you."
"When you then take a medical-grade thing that's single-use and put it in the general public, we're not worried about you cross-contaminating different environments you're being in. It's really about providing protection to you."
Bromage added that N95s "used to be only $1 or so each" but have seen an increase in sales to meet their high demand brought on by the COVID-19 pandemic and recent omicron variant surge.
Properly fitted N95s are reported to better prevent tiny particles from getting into the nose or mouth of individuals who wear them than cloth masks because of certain materials, including polypropylene fibers, work as a stronger barrier to aerial infection.