Repeating warnings from @H_S_E and @NIOSH about earloops having a low fit test pass rate is unpopular, but what does the published literature say about earloop KN95s? #KN95
One study found that “KN95 masks failed fit testing in all (82 out of 82, 100%) healthcare workers evaluated”. openres.ersjournals.com/content/6/4/00…
Another study of #KF95 mаsks found that: “A result of ‘failed’ was recorded for 39 of 42 fit test episodes”. ijic.info/article/downlo…
Another study showed KN95s had an average fit factor of 2.2 out of the 100 points needed to pass. journals.plos.org/plosone/articl…
When headstrap Ν95s were modified to take earloops (ELSS), the Fit Factor scores immediately dropped, causing wearers to fail (but improved with a novel fitting system, NFS). The Aura 1860+ dropped from an FF of 161.6 ± 46.9 to less than half of that. academic.oup.com/annweh/article…
The last paper shows that even if you get a lucky freak pass on an earloop respirator, your FF score will be bettered by an equivalent headstrap respirator. It really is true that headstraps respirators are generally better.
And no, I know nothing about the novel faceseal system. I can't find anything on it being for sale. If you added it to the headstraps I imagine it would improve the fit factor there too. isrp.com/the-isrp-journ…
This table is really quite depressing. Going from headstraps to earloops more than halved the Fit Factor. That's double the inward leakage. It's just not worth it.
Look at this study again. That's a 92.85% failure rate for KN95s, despite subjects being allowed to tweak their mаsks to improve the fit. Even if you belong among the 8% who pass, you shouldn't be recommending them to the 92% who don't, as you'll condemn them to be infected.
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