Simple Respiratory Mask (2006) | Hacker News Reader

Simple Respiratory Mask (2006)

ncbi.nlm.nih.gov

25 pointssubroutine8 comments

>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.

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.

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.)

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.

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)

> "You aren't supposed to wear them if you aren't sick"

You must exude healthiness.

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.

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

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