TY - JOUR
T1 - A highly efficient cloth facemask design
AU - Cappa, Christopher D.
AU - Ristenpart, William D.
AU - Barreda, Santiago
AU - Bouvier, Nicole M.
AU - Levintal, Elad
AU - Wexler, Anthony S.
AU - Roman, Sanziana A.
N1 - Funding Information: The authors greatly appreciate the participation of the various professional and amateur singers who volunteered their time. We thank Helen Dahlke at UC Davis for use of the CO2 and O2 sensors. Publisher Copyright: © 2021 American Association for Aerosol Research.
PY - 2021/1/1
Y1 - 2021/1/1
N2 - Wearing masks and face coverings helps reduce transmission of respiratory diseases. Much prior research on mask filtration efficiency has focused on fabric type, with less consideration given to mask design and shape. Here, we present evidence that increasing the mouth-mask separation distance engenders an increase in the mask-fabric filtration efficiency toward expiratory aerosols emitted via vocalization, which we attribute to a decrease in the expiratory jet velocity and expansion of the breath-mask contact area. We further assess the performance of a new reusable cloth facemask design, originally made for, but not exclusive to, professional singers and having a large mouth-mask separation distance. With proper fitting, these masks achieve overall filtering efficiencies of >93% for both exhaled expiratory aerosols >0.5 microns in diameter from singing and speaking and for inhaled ambient aerosols, better than surgical masks and approaching N95 respirators. Air exchange between the mask deadspace and the ambient environment limits the extent of CO2 buildup and in inhaled air and maintains O2 levels near ambient. The mask design also provides for less inhibited mouth and jaw movement and lower relative humidity, suggesting it may provide a more palatable, high-efficiency alternative to medical-grade masks for the public.
AB - Wearing masks and face coverings helps reduce transmission of respiratory diseases. Much prior research on mask filtration efficiency has focused on fabric type, with less consideration given to mask design and shape. Here, we present evidence that increasing the mouth-mask separation distance engenders an increase in the mask-fabric filtration efficiency toward expiratory aerosols emitted via vocalization, which we attribute to a decrease in the expiratory jet velocity and expansion of the breath-mask contact area. We further assess the performance of a new reusable cloth facemask design, originally made for, but not exclusive to, professional singers and having a large mouth-mask separation distance. With proper fitting, these masks achieve overall filtering efficiencies of >93% for both exhaled expiratory aerosols >0.5 microns in diameter from singing and speaking and for inhaled ambient aerosols, better than surgical masks and approaching N95 respirators. Air exchange between the mask deadspace and the ambient environment limits the extent of CO2 buildup and in inhaled air and maintains O2 levels near ambient. The mask design also provides for less inhibited mouth and jaw movement and lower relative humidity, suggesting it may provide a more palatable, high-efficiency alternative to medical-grade masks for the public.
KW - Shanna Ratnesar-Shumate
UR - http://www.scopus.com/inward/record.url?scp=85113319120&partnerID=8YFLogxK
U2 - https://doi.org/10.1080/02786826.2021.1962795
DO - https://doi.org/10.1080/02786826.2021.1962795
M3 - Article
SN - 0278-6826
VL - 56
SP - 12
EP - 28
JO - Aerosol Science and Technology
JF - Aerosol Science and Technology
IS - 1
ER -