Cotton was the most effective fabric out of 32 types of materials tested. 

As coronavirus numbers begin to shoot up across the American South, medical experts are reinforcing the importance of wearing a mask or face covering. Ever since the pandemic began, people have been on a quest to find the right mask to protect from the coronavirus. Researchers at the National Institute of Standards and Technology and Smithsonian Institution’s Museum Conservation Institute evaluated 32 types of natural and synthetic fabrics to find out how well they filtered out virus particles. The fabric that worked the best was made of 100 percent cotton with a raised fiber. However, none of the fabrics performed as well as an N95 mask.

The cotton mask worked even better when it was layered and was fitted tightly to the face. Researchers Christopher Zangmeister and James Radney, experts in measuring aerosols, used fabric squares instead of actual masks in the experiments. 

“Basically, we take a swatch of material and flow a stream of particles of a known size at it,” said Zangmeister. “We count the number of particles in the air before and after it’s passed through the fabric. That tells us how effective the material is at capturing particles.” 

cloth spools

Photo by Digital Buggu from Pexels

Table salt, or sodium chloride, is recommended by the CDC as a substitute for live viruses and was used in this study. The most effective fabric tested—cotton—blocked 20 percent of the salt particles. The researchers also tested other fabrics like HEPA filters, surgical masks, and coffee filters. Even when they paired these items with a layer of fabric, the outcome wasn’t much different.

Cotton fabrics with raised textures like flannel were the most effective. So if you can’t find an N95 mask, grab some of your old flannel pajamas and a sewing machine and make your own!