[ntenenz]

This is horrendously incorrect. Surgical masks do not filter aerosolized particles at the same effiency as an N95. For an airborn virus, that's a pretty big deal, especially for HCP who are constantly exposed to high viral loads.

[asdfasgasdgasdg]

When worn normally, or when well sealed? Are there tests of this? If they are both melt blown fabric then it seems at least plausible that this thing could work. It should be tested of course, but it seems like they are in the process of doing that.

[ntenenz]

http://aaqr.org/files/article/668/36_AAQR-13-06-OA-0201_991-...

[asdfasgasdgasdg]

Thanks. For those not following the link, this study shows that NaCl aerosols penetrate measured surgical masks at a much higher rate than n95 masks, even after creating a firm seal.

[tssva]

It is hard to tell what exactly was tested in this study. It mentions the standards which the tested respirators met but there is no mention of any standards regarding the tested surgical masks. Were they surgical masks that met the ASTM standards for surgical masks? If so the level 1, 2 or 3 standards?

The solution Save The Face Mask proposes is designed to work with surgical masks which meet ASTM standards. Given the lack of information regarding the masks tested the quoted study is fairly useless in evaluating the proposed solution.

[DanBC]

I don't understand your question, because you cannot seal surgical masks.

Here's one test. They got people with covid-19 to wear a mask and then cough onto petri dishes. Only 4 people, but the methods are clear.

https://annals.org/aim/fullarticle/2764367/effectiveness-sur...

> Discussion: Neither surgical nor cotton masks effectively filtered SARS–CoV-2 during coughs by infected patients. Prior evidence that surgical masks effectively filtered influenza virus (1) informed recommendations that patients with confirmed or suspected COVID-19 should wear face masks to prevent transmission (2). However, the size and concentrations of SARS–CoV-2 in aerosols generated during coughing are unknown. Oberg and Brousseau (3) demonstrated that surgical masks did not exhibit adequate filter performance against aerosols measuring 0.9, 2.0, and 3.1 μm in diameter. Lee and colleagues (4) showed that particles 0.04 to 0.2 μm can penetrate surgical masks. The size of the SARS–CoV particle from the 2002–2004 outbreak was estimated as 0.08 to 0.14 μm (5); assuming that SARS-CoV-2 has a similar size, surgical masks are unlikely to effectively filter this virus.

> Of note, we found greater contamination on the outer than the inner mask surfaces.

[asdfasgasdgasdg]

Isn't the whole point of the apparatus we are discussing to create a better seal with a surgical mask? The study another person linked to here hot-glued the masks being tested to their testing appliance, which does seem to create a seal.

[Aeolun]

It seems to me the structure is a bit different. Much more material for the N95 rated ones.

Though to be fair, my reusable KN95 (claimed), from China is just as thin as a surgical mask.

[asdfasgasdgasdg]

Tbh I don't know anything about it. Their blog post seems technical and well-thought out. They aren't offering these things for sale at $50 a pop, so they're not trying to gouge the public. They are going through the necessary testing. It doesn't seem like an effort that can be slapped down with internet comment outrage.

[dragonwriter]

> Surgical masks do not filter aerosolized particles at the same effiency as an N95. For an airborn virus, that's a pretty big deal,

Last I heard, COVID-19 transmission by aerosols vs. droplets was controversial, and only droplet rather than airborne precautions are generally seen as necessary for it.

Also, a big reason (but, yes, not the only one) that surgical masks are less effective against aerosols is that they don't tightly seal, so the most effective part is routinely bypassed by aerosols.

[DanBC]

That's what we thought a month or so ago. The science with SARS-CoV-2 is developing, and currently we think people need to be careful with large and small droplets. Large droplets fall out of the air quickly; small droplets can be blown further.

The infectious dose for covid-19 is very small, so getting hit by a few large droplets or more small droplets is about the same.

There's no real standard definition for "aerosol" which makes these conversations trickier.

[def8cefe]

From my understanding aerosolized transmission is a greater concern in healthcare settings, especially where ventilators are being used.

[kleiba]

Two opposing opinions. Are there relevant references to support one side or the other?

[sgc]

Sure, one is certified by a professional body (NIOSH etc) and the other is not. Since it's not, the burden of proof in this case is one sided.

For example: "Surgical N95 respirators are approved by NIOSH as to their respiratory protection efficiency and resistance and other NIOSH requirements. They are also separately cleared by FDA as medical devices. FDA clears surgical masks for sale in the United States but does not test and certify the respirator."

[asdfasgasdgasdg]

I think they have accepted that burden of proof? They are trying to go through the cdc testing process with their brace, according to the FAQ.

[rovr138]

What I would appreciate is more information on this part from them.

What have they done? What testing? How are they measuring particles? What’s the process and what stage are they on?

If they provided more information/transparency the conversation would be VERY different (if the numbers where close to n95 at least)

[hogFeast]

Yes, the fact that the masks in questions are (it would appear) not certified as N95.