Why stop at double mask? TRIPLE masks are now the standard!
next segment: wrapping your head in saran wrap achieves 140% efficiency
DOUBLE MASK EFFICIENCY: 75% TRIPLE MASK EFFICIENCY: 90% Source: January 15, 2021 study by Monica Gandhi, Linsey Marr CNBC
source: https://www.cnbc.com/video/2021/01/25/is-a-double-mask-really-better-than-a-single.html
related: https://bbs.institute/post/612