Face masks: Here are the best and worst materials for protecting against coronavirus

A study from the University of Arizona finds that some face mask materials are more protective against COVID-19 infection than others.

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Alison DeNisco Rayome
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Some masks protect better against the coronavirus than others.

Dan Ackerman/CNET

Everyone should wear nonmedical face masks when interacting with others during the coronavirus pandemic, according to the US Centers for Disease Control and Prevention. But the material your mask is made from may make a difference when it comes to reducing the spread of the virus, a study published in the Journal of Hospital Infection earlier this month found.

Researchers from the University of Arizona's Mel and Enid Zuckerman College of Public Health collected data from different studies of mask efficacy, and created a computer model to simulate how well different nontraditional mask materials protect a person from infection in a highly contaminated environment.

Risk of infection is based on how long you're exposed; the number of people around you and their distance from you; and the size of virus-transporting droplets from sneezing, coughing or talking. The research assessed risk in the contaminated environment after 30 seconds and again after 20 minutes. 

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Wearing any mask was better than wearing none at all, the research found. Wearing a mask reduced infection risks by 24 percent to 94 percent, or by 44 percent to 99 percent depending on the mask and the exposure duration. 

The most protective options were N99 masks, which reduced average risk by 94 percent to 99 percent during both exposure times. However, these are difficult to come by, and many are reserved for medical professionals, researchers said. 

Read more: Where to buy a face mask online right now

After that, the most protective masks were N95 and surgical masks, and, surprisingly, vacuum cleaner filters, which you can insert into filter pockets in cloth masks. The vacuum filters reduced infection risk by 83 percent for a 30-second exposure, and by 58 percent for a 20-minute exposure.

Tea towels, cotton-blend fabrics and antimicrobial pillowcases were the next most protective items. The more dense the fibers in a mask's material, the better it is at filtering. Therefore, higher thread counts lead to higher efficacy, Wilson said in the release. 

The materials that were the least effective at blocking the virus were scarves and cotton T-shirts, the study found. 

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Watch this: What you need to know about cleaning and reusing a virus mask

For every type of mask studied, risk reduction decreased as exposure duration increased -- so the longer you're exposed to the virus, the more likely you are to get it, even with a mask on, the researchers found. 

"That doesn't mean take your mask off after 20 minutes," Amanda Wilson, an environmental health sciences doctoral candidate at the University of Arizona, and the lead author of the study, said in a Wednesday press release. "But it does mean that a mask can't reduce your risk to zero. Don't go to a bar for four hours and think you're risk free because you're wearing a mask. Stay home as much as possible, wash your hands often, wear a mask when you're out and don't touch your face."

No matter what kind of mask you're using, it's important that it has a good seal that pinches at the nose. You shouldn't wear a mask under your nose or tuck it under your chin, Wilson said in the release.

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"Proper use of masks is so important," Wilson said in the release. "We were focusing on masks protecting the wearer, but they're most important to protect others around you if you're infected. If you put less virus out into the air, you're creating a less contaminated environment around you. As our model shows, the amount of infectious virus you're exposed to has a big impact on your infection risk and the potential for others' masks to protect them as well."

For more, read up on what we know about face masks and coronavirus protection, whether you can become infected with the coronavirus through the air and more information about where it's required to wear masks

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.