Choosing the best mask to protect you and others

Wearing a mask not only protects others from your expelled respiratory droplets, it protects you as well, according to new guidance from the US Centers for Disease Control and Prevention.

The evidence is piling up that masks work in terms of driving down the risk for everyone," said Harvard environmental health researcher Joseph Gardner Allen, who directs the Healthy Buildings program at the Harvard T.H. Chan School of Public Health.

But what type of mask will offer you and others the best protection from any novel coronavirus circulating in the air?

"You want to have a minimum two-ply mask, preferably a three-ply mask," said Allen, who has focused his career on "sick buildings" and how they affect worker performance and productivity.

Stay away from bandanas and gaiter masks unless that's all that's available. A recent study found both types to be the least effective in terms of protection.

"In addition to level of filtration, we have to pay attention to fit," Allen continued. "You want the mask to go over the bridge of the nose, below the chin and be flush on the face, resting along the skin. You want your breath going through the filter media and not escaping out the sides."

We found that silk face coverings repelled droplets in spray tests as well as disposable single-use surgical masks," the authors wrote, adding that silk masks "can be more breathable than other fabrics that trap humidity, and are re-useable via cleaning."

That brings up an important point: To avoid trapping germs that might irritate your face or reduce the mask's effectiveness, reusable masks should be washed daily with soap and hot water. Don't wear the mask again until it's completely dry -- it's harder to breathe though wet fabric.

"If you use a filter in your mask, be sure to change it regularly because it can clog. You can tell if it gives you a sensation that's a little harder to breathe," said Emory's Sexton.