Dr. Howard Smith Oncall

  Vidcast:  https://youtu.be/dTP7zejb2ok   British engineers assess which available materials create masks that filter out coronaviruses while permitting breathing.   The best single layer micro-particle filter is HEPA vacuum cleaner cloth and paper bag material.  Next best in terms of filtration are thickly felted wool, quilting cotton, cotton flannel, and nonwoven fusible interfacing material such as HTC.    Multilayers work best.   Two socks or a doubled neck gaiter with a layer of HEPA vacuum cleaner bag within would be very efficient.  Studies show that a mask of quilting cotton, cotton batting, and two layers of HTC will protect better than an N95 mask if tight fitting on your face.   https://www.medrxiv.org/content/10.1101/2020.04.14.20065375v1.full.pdf   #covid19 #coronavirus #mask #hepafilter