Read on Twitter
THREAD
1/ New paper out in @JAMAInternalMed on evaluating different types of MASKS and their filtration efficiency in indoor settings for #covid19
1/ New paper out in @JAMAInternalMed on evaluating different types of MASKS and their filtration efficiency in indoor settings for #covid19
2/ They used a particle generator that put out sodium chloride aerosol particles “slightly smaller” than a #SARSCOV2 virion; the environment was set to mimic typical indoor settings #covid19
3/ They measured the fitted filtration efficiency (FFE)- essentially by looking at the concentration of particles that got through the mask (using a sampling probe in the mask) vs the concentration in the air - total testing time of 3 minutes #covid19
4/ They tested consumer grade face masks (various mixes of nylon, cotton, polyester, polypropylene)
and medical procedure masks w/ and w/o **enhancements** (see image, diff ways of tying the ear loops etc)
#covid19
and medical procedure masks w/ and w/o **enhancements** (see image, diff ways of tying the ear loops etc)
#covid19
5/ This table has the summary of what they found
NIOSH approved N95 masks were far and away the best— FFE of 98.4%
Other masks...well, you can see in the chart
NIOSH approved N95 masks were far and away the best— FFE of 98.4%
Other masks...well, you can see in the chart
6/ As many have been saying, the *FIT* of the mask is so critical.
Procedure masks w/ ear loops, normal fit —> 38.5%
W/ fit modifications, as high as 80.2% (check out the nylon hosiery sleeve mod lol)
3 rubber bands also do well
Procedure masks w/ ear loops, normal fit —> 38.5%
W/ fit modifications, as high as 80.2% (check out the nylon hosiery sleeve mod lol)
3 rubber bands also do well
8/ LIMITATIONS
•only tested on one subject— your facial characteristics are bound to affect the fit of the mask which matters
•this is a laboratory environment looking at movement of particles; transmission of disease is far more complex (infectious dose etc)
#covid19
•only tested on one subject— your facial characteristics are bound to affect the fit of the mask which matters
•this is a laboratory environment looking at movement of particles; transmission of disease is far more complex (infectious dose etc)
#covid19
9/ As many of you know, better masks for the American public has been something really important to me & my colleagues @sri_srikrishna @RanuDhillon ; we have written about this many times #covid19 https://hbr.org/2020/06/we-need-better-masks
10/ As infection spreads quickly, both droplet AND aerosol contribution become more significant; if many more people in a grocery store are infected at the same time, for instance, better fitted, better filtration masks are all the more important here #covid19
