There’s a chance you made your COVID-19 mask wrong (plus how to make it better)

The Centers for Disease Control and Prevention now recommends that people wear face coverings when leaving homes to public places like grocery stores or using the train. It was a quick turnaround after the CDC first said facemasks were not necessary but flip-flopped its advice Friday after new information on how the coronavirus can spread made the recommendation necessary.

New York City Mayor Bill de Blasio urged New Yorkers to wear masks over their faces when going outside, even suggesting residents to create their own homemade mask.

“We’re advising New Yorkers to wear a face covering when you go outside and near other people,” de Blasio said last Thursday. “It can be a scarf, it can be something you create at home it can be a bandana.”

With medical masks still needed by health professionals, it’s not uncommon to see people on the streets covering their mouths with scarfs, bandanas, and other fabrics. But while making your own mask at home can come in handly, it all depends on the materials in the fight against COVID-19, according to a new study.

Researchers at Wake Forest Baptist Health evaluated 13 different designs from about 400 masks made by volunteers. The doctors and scientists wanted to find out which mask removed particles 0.3 – 1.0 microns in diameter, which are the size of many viruses and bacteria. They compared it to surgical masks and N95 respirators, which have been used in the fight against coronavirus.

“We saw the possibility that we could face a shortage of surgical masks in the hospital and wanted to investigate the possibility of using cloth masks as an alternative as long as they worked and provided good protection for our doctors, nurses and patients,” Scott Segal, M.D., chair of anesthesiology at Wake Forest Baptist, said in a press release.

After conducting tests, researchers determined that masks’ effectiveness varied. The top homemade masks had 79% filtration compared to surgical masks (62% to 65%) and N95 masks (97%). However, some homemade masks virtually did nothing to protect, with a few having only 1% filtration, according to the study.

By fibers, two layers of high-quality, heavyweight quilter’s cotton with a thread count of 180 or more performed the best, according to researchers. They suggested double-layer masks with a cotton outer layer and flannel inner layer also performed well, but single-layer makers and double-layer patterns with lower-quality cotton were considered inferior.

“As important as this information is for hospitals, it is also important for people who want to make masks for their own use,” Segal said. “We don’t want people to think that just any piece of cloth is good enough and have a false sense of security.”

The research has not been submitted for publication and has yet to be peer-reviewed, according to NBC.

If you’re considering making your own mask, all you need is scissors, sewing supplies, a ruler, fabric, and an elastic ribbon to keep yourself safe during the COVID-19 pandemic.