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How to choose the best face mask filter, according to experts

Experts saying using a filter can provide an additional layer of protection from airborne particles.
Woman replacing a face mask filter in her cloth facemask
Getty Images
/ Source: TODAY

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We're basically used to wearing face coverings while out and about at this point, and you might have noticed that several masks have a small slot to place a filter for extra protection.

Adding a filter in between the layers of your face mask can help block airborne particles that might sneak through the fabric and can offer some much needed reassurance during these uncertain times.

Luckily, you don't have to spend a fortune on face mask filters, as there are several budget-friendly options available online. To help you get started, Shop TODAY consulted a few health experts to learn what filter materials are most effective, how often you should swap them out and where you can buy them online.

Why you should use a filter in your face mask

When used in conjunction with social distancing practices, cloth face masks can help slow the spread of coronavirus. However, not all masks are created equally, and some offer more protection than others.

"Homemade masks use various cloth materials that are all much looser weave than a medical-grade mask, such as an N95, but those masks need to be reserved for hospital use and health care professionals who cannot maintain social distancing with patients under their care," said Dr. Ruth L. Bush, associate dean of medical education and a professor at the University of Houston College of Medicine.

Thicker, tightly woven materials offer more protection, and homemade masks should ideally have two cloth layers to make them more effective. If you're wearing a mask made of a thin fabric, adding another layer in the form of a filter can provide added protection.

"When placed in between the layers — such as with a pocket style opening allowing for insertion and removal — you could insert a filter which will make the mask more effective and provide extra protection against allowing viral particles into the air when you talk, cough or breathe," Bush said.

What to look for in a face mask filter

Medical-grade masks are in short supply and should be reserved for health care professionals who need them most, but that doesn't mean you can't add a little extra protection to your cloth face mask.

Many brands have started offering filters online. Experts also say household staples like coffee filters and paper towels can double as face mask filters in a pinch and should be inserted in between layers of fabric and replaced after each use.

"Many masks available for purchase online have a pocket or pouch in which you could add a filter. Masks that have a looser weave, are more porous or made of very thin fabric may protect others better with the addition of a filter," Bush said.

Of course, filters and masks aren't the only way to protect yourself and others against coronavirus, but they sure can help. "Research has shown that some loosely woven masks only block 10-20% of particles, but by adding one or more layers of filter material, higher percentages of particles could be blocked," Bush said.

Where to buy filters online

1. Vistaprint Filter (Pack of 10)

The main goal of a face mask filter is to block airborne contaminants, and this one gets the job done without trapping moisture. Simply slip it in and replace it after each use. "Filters last until they are wet from breath or other liquids. They should be changed when soiled or wet and not used more than once," said Dr. David M. Aronoff, director of Vanderbilt University Medical Center's Division of Infectious Diseases. Use the code FAST25 at checkout, and get 50% off.

2. MERV13 Reusable Filters

The term MERV stands for "Minimum Efficiency Reporting Value," and these filters block particles smaller than one micron in size.

"This type of filter is probably most useful for people who will be having sustained or frequent close contacts with other people, particularly people who are not themselves wearing any type of mask," Aronoff said.

3. MERV16 Filter (Pack of 10)

"The higher the MERV value, the more efficient the filter will be in trapping airborne particles," Aronoff said. These lightweight filters are made of one of the highest MERV values around, and they fit comfortably in cotton face mask filter pouches.

4. Steve Madden Mask Filters (Pack of 20)

This PM 2.5 activated carbon (also known as activated charcoal) filter blocks up to 95% of airborne particles — everything from germs and dust to chemicals and pollen — thanks to several strong layers, including a high-efficiency filter cloth and an anti-stick cloth. "A tighter filter can help prevent inhaling small droplets in the air we breathe," Aronoff said.

5. Vida Protective Mask Replacement Filters (Pack of 5)

Five layers of fabric band together to create this PM 2.5 activated carbon filter. The material is effective at filtering chemicals and gasses and can serve as a nice face mask filter, as long as the mask is tightly woven.

6. Casetify PM 2.5 Carbon Filters (Pack of 10)

Each Casetify mask comes with two filters to get you started, but the brand also sells a pack of 10 replacement filters formulated with five protective layers that block close to 95% of particles. The best part? Casetify donates a mask to health care workers for every mask sold.

7. 3D Print-Knit Mask Filter Pack (Pack of 10)

After testing these filters, global lab Nelson Labs found that they provide more than 95% Bacterial Filtration Efficiency (BFE), which helps block harmful particles in the air.

"The virus spreads through respiratory droplets that another person breathes in or that land on a surface that is then touched and transferred to the person’s nose or mouth," Bush said.

8. Activated Carbon Filter (Pack of 20)

As with any other filter, just make sure you test it with your mask and make sure air flows freely. "If your glasses are fogging up, then the material is not allowing air to flow through and your breath is going up, around the filter and out the sides of your mask," Bush said.

9. Ouba Activated Carbon Filter (Pack of 20)

These activated carbon filter inserts are currently the No. 1 bestselling option on Amazon. With five layers of filtration, these breathable filters can also be used with face masks for outdoor activities.

10. Handmade HEPA Filter Insert

Joel Burken, chair of the department of civil, architectural and environmental engineering at Missouri University of Science and Technology, previously told TODAY that he recommends using HEPA filters for fabric masks. These HEPA filter inserts are already cut and sewn to fit most face masks.

11. MERV13 Disposable Filter (Pack of 10)

These MERV13 filters can be trimmed to fit in both adult and kids' masks with filter pockets. The charge of the fabric is meant to attract particles and trap them to efficiently filter the air through the mask. According to the product description, these specific filters are also hydrophobic, so they won't absorb moisture over prolonged periods of time.

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This story was originally published on June 1, 2020.