Nine months into the coronavirus pandemic, do you know what type of face mask you should be wearing? How about what filter to put in the middle of a two-layer mask with a pocket?
Dr. Linsey Marr, professor of civil and environmental engineering at Virginia Tech and an expert in airborne disease transmission, said there are two types of masks that provide the best protection.
The first is a surgical mask from a reputable company.
“Those act as filters pretty well, but the fit isn’t great,” said Dr. Marr. “So, what we suggest is you put on a surgical mask, and then put a cloth mask over it to help hold it more closely to your face. And, the cloth mask will also provide an extra layer of filtration.”
The second is the three-layer mask recommended by the Centers for Disease Control and Prevention.
“Certainly, our research and others have shown that the three-layer mask is going to offer the best protection,” she noted.
For people who have two layer masks with a pocket, the best materials to use in the middle are those that are specifically designed to be filters, Dr. Marr said on KCBS Radio’s “Ask An Expert.”
“The best thing to use would be a HEPA filter,” she added. “You can even go buy one of those that’s for portable air cleaners and cut it out of the frame, and then use that.”
Dr. Marr also recommended HVAC filters that are rated MERV 14 or above, which can be found at home improvement stores.
Plus, Dr. Marr said studies show that certain types of coffee filters and vacuum bags work very well, too.
If people don’t have those types of masks, Dr. Marr said two cotton ones are better than nothing.
“Even a mask from a cotton t-shirt, especially if you double it over, will get you at least half way there to, let’s say, more ideal protection,” the expert said.
To avoid contamination, Dr. Marr suggested people be careful when putting on and taking off their masks, and clean them regularly.
“When you’re putting them on and off, to avoid touching the front of the mask, kind of use the ear loops or handle it by the edges,” said Dr. Marr. “When you do take it off, put it somewhere out of the way. Put it out in the sunshine. We know the sun kills off the virus pretty well."
She said to wash cloth masks in detergent regularly, but be aware that some types of filter materials should not be washed.
