
Simple Respiratory Mask (2006) - subroutine
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3373043/#!po=12.5000
======
gruez
>A commercially available N95 respirator requires a fit factor of 100 to be
considered adequate in the workplace. The prototype mask achieved a fit factor
of 67 for 1 author [...] The other 2 authors with LANL panel face size 10, the
largest size, achieved fit factors of 13 and 17 by making the prototype mask
inner layers slightly larger

So what's the actual effectiveness of this then? Does a fit factor of 67 mean
your chances of getting infected (over what time?) is 33%? What about for the
other two guys with fit factors of 13 and 17? I wouldn't risk a 87% or 83%
chance of getting infected.

~~~
subroutine
According to OSHA

" _Fit factor is a quantitative estimate of the fit of a particular respirator
to a specific individual, and typically estimates the ratio of the
concentration of a substance in ambient air to its concentration inside the
respirator when worn._ "

So I guess 100% would be like if the test aerosol had an ambient concentration
of 100 µg/cubic meter, inside the mask the concentration would be < 1 µg/m3.

67% would be 33 µg/m3.

Doesn't seem like a fool proof mask but there is prelim evidence that the
initial virus load has an effect on symptom severity. If you could cut
exposure to 1/3 i suppose that is better than nothing.

------
lsc
so wait, is it OK to use masks now? last time I went out with a mask I got
chewed out by a clerk. It was... deeply weird. (I mean, I understand the guy
had probably had a hellish day and that probably had more to do with it than
anything, and I apologized and did what I could to diffuse the situation. But
it was deeply weird, 'cause normally the economic inequality here in the bay
area means that I'm treated really well.)

~~~
subroutine
When was this? Last week Trump said this was overblown; yesterday he said he
was ringing alarm bells before anyone else. Seems like a lot of tunes have
changed in just the last few days.

Also I'm curious what did this person say to you? Seems like a weird thing to
get upset about for any reason.

~~~
lsc
This was the day before the shelter in place order was announced. The guy was
going on under his breath about how people don't know how this thing was
transmitted, that you aren't supposed to wear them if you aren't sick. He said
it in this really sort of stressed out and angry kinda way. I apologized in
what I hope was a really sincere kind of way

(I mean, I... am not going to be angry at someone who works retail at a time
like this, short of maybe getting physically attacked. I know I'm feeling bad
'cause I am working from home and have to deal with my own lack of discipline
and have to cook for myself now. I have top-shelf medical insurance and
unlimited sick time. I can only imagine that those on the front lines, getting
sneezed on all day with none of those benefits are in bad shape.)

Dude said "It's not your fault, it's the media" and generally seemed mollified
- I mean, if this were facebook, I'd fire back something about how I don't see
how his media is any more accurate than mine, considering neither of us are
experts... and if you are supposed to wear a mask if you are sick, well,
almost none of us actually _know_ if we are sick. But this was a face to face
interaction, so I sincerely wished him good health and finished the paperwork
(before quarantine, I'd use 'order online, pick up in store' orders to
minimize time in store)

~~~
subroutine
> " _You aren 't supposed to wear them if you aren't sick_"

You must exude healthiness.

------
teeray
It would be more difficult to scale, but I wonder if you could scan facial
features and 3d print a frame to improve fit. The back half could be
standardized where the cloth is actually fitted so that the boiling of shirts
could proceed independently from building the frame.

------
agumonkey
can't you use cyclonic filtering ? ala recent vacuum cleaner

