"The best masks were constructed of two layers of heavyweight "quilters cotton" with a thread count of at least 180, and had thicker and tighter weave.
Lesser quality fabrics also worked well, as long as they had an internal layer of flannel.
"You do want to use a woven fabric, like batik," Segal said, "but you don't want to use a knit fabric, because the holes between the knit stitches are bigger."
In other words, if the fabric allows for a substantial amount of light to shine through, it's probably going to allow tiny viral particles through, as well.
Other hospitals, such as Vanderbilt University Medical Center in Nashville, have also suggested using tightly woven fabrics for do-it-yourself facial coverings. Kaiser Permanente has also published instructions on DIY masks, also calling for two layers of cotton fabrics."
Lesser quality fabrics also worked well, as long as they had an internal layer of flannel.
"You do want to use a woven fabric, like batik," Segal said, "but you don't want to use a knit fabric, because the holes between the knit stitches are bigger."
In other words, if the fabric allows for a substantial amount of light to shine through, it's probably going to allow tiny viral particles through, as well.
Other hospitals, such as Vanderbilt University Medical Center in Nashville, have also suggested using tightly woven fabrics for do-it-yourself facial coverings. Kaiser Permanente has also published instructions on DIY masks, also calling for two layers of cotton fabrics."