Homemade masks for COVID-19: What works, what doesn’t?

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Using flannel-lined fabric to make a face mask is good protection against the spread of COVID-19, advises Dr. Scott Segal. Credit: Dr. Scott Segal.

By this Friday, LA Mayor Eric Garcetti wants everyone who works at — or visits — an essential business to wear a face mask. 

“if you’re shopping for groceries, if you’re picking up your prescription, or visiting any other essential business, you will need to cover your face. And if you’re not covering your face by Friday morning, an essential business can refuse you service,” Garcetti said. 

But masks are a scarcity around the city now. Some local fashion brands have started selling them online, like Reformation, Los Angeles Apparel, and Silverlake-based Matrushka. 

Others are creating their own facial coverings from bandanas, vacuum bags, pillow cases, and other miscellaneous items around the house. 

Dr. Scott Segal, MD, MHCM, recently studied homemade masks. He’s chairman of anesthesiology at Wake Forest Baptist Health in North Carolina.

"The simplest way to tell if it's a decent filtering mask is to hold it up to a bright light or to the sun, and to see how easily you can see the light passing between the fibers of the cloth. If it passes easily, it's probably not a great filter. If it tends to block more of the light, it probably filters better,” Segal says. 

However, he stresses: “There is no mask that is as good as staying home or social distancing. Nothing will ever work as well as that. So you should still try and practice social distancing and good hand hygiene, no matter what you decide to wear.” 

Higher quality fabric: Weave is tight, and not much light passes through the fibers of the cloth. 

Flannel-lined fabric is also effective. 

Lower quality fabric: More light penetrates through the fibers, and filtering is reduced.

Credit for all photos: Dr. Scott Segal. 

— Written by Amy Ta and Alex Tryggvadottir, produced by Alex Tryggvadottir