Life with a mask doesn’t appear to be going away anytime soon. And while any mask is better than no mask to help contain the spread of COVID-19, all masks are not created equal.
The state’s covid19.ca.gov website puts it bluntly: “When you’re around anyone you don’t live with, you must have a mask covering your nose and mouth.”
The California Department of Public Health advises, “The use of face coverings by everyone can limit the release of infected droplets when talking, coughing, and/or sneezing, as well as reinforce physical distancing.”
Cloth face coverings, rather than medical-grade N95 masks and surgical masks, are recommended for use by the general public by the Centers for Disease Control and Prevention (CDC). The CDC’ suggests N-95 and other medical-grade masks be reserved for use by healthcare workers and first responders.
So what are the best (and worst) everyday-use cloth masks?
Bandanas are the least effective. A Florida Atlantic University study found that droplets from a bandana-covered cough traveled more than 3 feet, but holding a double-folded handkerchief over your mouth was much more effective—stopping droplets from going more than 15 inches.
Basic cotton works well. Tightly woven, 100% cotton is efficient. Christopher Zangmeister, a researcher at the National Institute of Standards and Technology, told NPR that microscopic cotton fibers have a more three-dimensional structure than synthetic materials, which makes them more effective at snagging particles.
More layers are better. A mask with more than a single layer is important. Two layers of cotton are good, and three or more are better. The CDC recommends at least three layers.
Fit is key. It’s critical that a cloth mask fits snuggly to your face. If there are gaps where the mask contacts skin, its effectiveness is degraded. Pleated and duckbill-type masks allow more airflow through the mask and less out the sides compared to flat-front face coverings.
Neck gaiters and tubes: good and bad. Covering the nose down to the neck, these work well to solve the air-leakage problem, and are comfortable without having to fuss over ear loops and ties. However, they are typically made out of polyester and/or spandex, both of which are less effective at filtering particles than cotton.
Avoid masks with vents or exhalation valves. These features make breathing easier, but they defeat the purpose of the mask because they release unfiltered air that can contain droplets. An exception is that some vented masks have filters that trap exhaled droplets. The Mayo Clinic has banned the use of vented masks on all of its campuses.
There is a mountain of scientific evidence that masks work to control the spread of COVID-19. A statement on California’s covid19.ca.gov sums it up best: “If each of us wears a mask, everyone is protected.” Visit the site for additional comprehensive guidance on masks and other COVID-19-related information.
