Homemade face mask study finds which two common materials are best

A newly published study looks into homemade face masks and which kinds of materials are best for filtering out potentially contaminated particles. The researchers found that two commonly available fabrics are the best options, but only if they're combined, leveraging the benefits of each...but only if the mask is made with a good fit, as well. The research comes amid widespread efforts to sew face masks for public use.

Guidance on wearing face masks to help protect against the novel coronavirus has been contradictory; the CDC and Surgeon General initially told Americans to avoid wearing masks but have since reversed that stance, advising the public to instead make their own masks and wear them while in public. Questions remain over the best materials to use.

The topic of homemade face masks and the most effective materials isn't new — there are a couple of existing studies that look into the best designs and the capabilities of a DIY mask. The latest research, which has been published by the American Chemical Society, comes from the University of Chicago's Supratik Guha and colleagues who found one combination that could offer performance close to that of an N95 mask.

The effective face mask involves tightly knit cotton fabric combined with two layers of a sheer fabric called polyester-spandex chiffon. If that material isn't available, the team found that substituting the chiffon for a cotton quilt, flannel, and natural silk could also offer similar performance.

The cotton layer on the outside helps filter out the particles, while the interior fabric has a static charge that helps stop particles from continuing past. There was a big catch, however, and it's that the mask must fit well in order to protect the user; a gap of only 1-percent was found to cut the masks' filtering capabilities by half at a minimum.