Here's What You Can Use as a Filter in Your Face Mask, According to a Doctor

Even as parts of the country reopen, it’s essential to wear a face mask in public to protect yourself and those around you. Face masks, as well as proper social distancing, are key to slowing the spread of the novel coronavirus. For most, homemade cloth masks or face coverings are sufficient, but you can take it a step further by adding a filter. POPSUGAR spoke with Arefa Cassoobhoy, MD, MPH, senior medical director for WebMD, about the kinds of materials to use and more.

Will Adding a Filter Make My Face Mask More Effective?

While it’s not 100 percent effective at preventing people from contracting COVID-19, using a mask and a filter is very helpful at slowing the spread of the virus. However, the mask and filter won’t do you any good if you can’t breathe properly. “You need to be able to breathe comfortably with the mask on, so you don’t have to slip it off while you’re in public to take a breath,” Dr. Cassoobhoy told POPSUGAR. “Also, you don’t want to have to fiddle with the mask – for example, if it’s stiff – and potentially contaminate your fingers touching the outside layer of the mask.” The mask should also still fit your face properly, so make sure when you add a filter that it doesn’t cause any bulges or gaps.

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What Can I Use as a Filter in a Fabric Mask?

If you made or purchased a well-constructed cloth mask, it most likely has more than one layer of fabric, which provides a bit of a filter in itself. Dr. Cassoobhoy told POPSUGAR that this extra fabric layer acts as a filter to block respiratory droplets while still allowing you to breathe comfortably. For extra protection, you can also use:

• Coffee filters: The Centers For Disease Control has recommended placing coffee filters in between layers of fabric in a mask.
• Reusable fabric grocery bags: Dr. Cassoobhoy pointed out that reusable grocery bags are usually made from polypropylene nonwoven fibers, so cutouts from these bags work well as a filter.
• Nylon pantyhose: The nylon from pantyhose can work as a filter as long as you place it over a mask. It shouldn’t be worn without one.
• HEPA filters: Dr. Cassoobhoy warns that, if you want to use a HEPA filter with your fabric face mask, you should do your research first. “HEPA filters can have fiberglass, which would be very dangerous to inhale,” she said.

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How Often Should I Change the Filter in My Face Mask?

Just like you’re washing your mask every time you wear it, you should also change out the filter with every use. If you’re using a disposable filter (such as a coffee filter), you should throw it out immediately after using it. If you’ve used another fabric (like pantyhose) as a filter, wash and disinfect it the same way you do your mask.