As new, more contagious variants of the new coronavirus spread around the world, public health officials are advising us to update our mask protection. One of the easiest ways to do this is to use two masks at the same time. Here are answers to common questions about what to do and what not to do with double masking.
Why do I need to make a double mask?
New variants of the coronavirus are more contagious. It may be that an infected person releases greater amounts of virus, or it may be that fewer virus particles are needed to make you sick. Anyway, a more contagious virus means that we need to wear masks that do a better job of catching infectious particles. Double masking can improve the fit of the mask, closing the gaps around the edges and creating multiple layers of protection against incoming or outgoing droplets.
Can I use two surgical masks?
The use of two disposable surgical masks together is not recommended. A standard surgical mask is a blue rectangle mask made of paper-like material. Although surgical masks are great filters against viral droplets, they tend to fit poorly, leaving gaps on the sides, which reduces their efficiency. Using two at the same time does not solve the adjustment problem. Adding a fabric mask on top of a surgical mask helps to close the gaps and creates a more comfortable fit. For help choosing a fabric mask, the Wirecutter team, which is owned by The New York Times, has some recommendations. (The mask in the video is the Graf Lantz Zenbu organic cotton facial mask.)
Should I apply a double mask with an N95 or KN95?
The N95 mask is the gold standard for medical masks, and the KN95, made in China, is similar. When used correctly, both masks will filter out 95 percent of the most difficult to capture particles. If you have access to a genuine N95 or KN95 and it fits well, you do not need to wear a double mask. The problem is that the N95 and KN95 masks are still difficult to find and the supply chain is full of counterfeits. Although the Centers for Disease Control and Prevention does not recommend the double mask with an N95 or KN95, you need to make sure you have the real one. If you are unsure or if it does not fit well, covering it with a cloth mask can help. (Another highly effective medical mask is the KF94, made in Korea. Counterfeits are usually not an issue with the KF94s, and if they suit you well, you will not need to wear a double mask.)
If I have a double mask, why do I need to tie a knot and fold my surgical mask?
The best way to use the double mask is to use a surgical mask as the first layer and cover it with a cloth mask. It is not necessary to tighten the surgical mask, but if it does not fit well, knotting the ear loops and bending the corners can improve your filtering efficiency by up to 20 percent. For a longer demonstration on how to adjust the fit of your surgical mask, you can watch this video from UNC Health.