Last week the federal Centers for Disease Control and Prevention (CDC) issued a strong recommendation for us all to wear face masks so that we don’t unwittingly spreading COVID-19. NOTE that unless you are wearing a medical grade (N95) mask, a facemask, especially if constructed of lightly woven cotton or other material, WILL NOT PROTECT YOU FROM GETTING COVID-19. Here are some guidelines on when and where to wear masks, why to wear them, and what to make them out of. Information is from the CDC, Oregon Health Authority, N.Y. Times (April 5, 2019), Indiana University, and the Missouri School of Science and Technology.
What to use to make an effective cloth face mask:
The best materials for homemade face masks: HEPA filters, vacuum-cleaner bags, and quilted materials! Scarves and bandanas alone, without any additional filtration material are not very effective. They can be augmented, according to the CDC, by folding a HEPA or even a coffee filter into the mask.
A story in the April 5, 2020 N.Y. Times story says that “In recent tests, HEPA furnace filters scored well, as did vacuum cleaner bags, layers of 600-count pillowcases and fabric similar to flannel pajamas. Scarves and bandana material had the lowest scores, but still captured a small percentage of particles.”
Research by Dr. Yang Wang at the Missouri University of Science and Technology has shown that for “do-it-yourself” masks, allergy reduction HVAC filter material worked well. It picked up 89% of potentially virus-carrying particles, according the April 5 N.Y. Times. Two layers of furnace filters captured 75 percent. For highly effective filters such as these, look for a minimum efficiency reporting value (MERV) rating of 12 or higher, or a micro particle rating of 1900 or higher. And to ensure that you are not inhaling small fibers from those filters, enclose the filter material in layers of cotton fabric—a bandana, tee-shirt, or 600-thread count cotton sheet.
Quilting material can also be an effective barrier for COVID-19 virus transmission. Tests performed at the Wake Forest Institute for Regenerative Medicine in Winston-Salem, N.C., showed good results for homemade masks using quilting fabric – high quality, high thread-count cotton. The best homemade masks in this study were as good as surgical masks or slightly better, testing in the range of 70 to 79 percent filtration.