Submitted by IceGroundbreaking715 t3_ysht77 in science
The methods used in this paper are pretty far from realistic. Worse, they keep making claims about things they do not have the data to show.
From "Results":
> "Even though not specifically related to virus transmission through water vapor and droplets32,33, measuring the relative humidity (RH) transmittance can be a simple, rapid and worst case method for testing the performance degradation of FFRs."
i.e., they use as a proxy for mask effectiveness against particles and droplets whether the relative humidity inside it changed over the course of an hour (Fig.2). That's highly questionable, as even with 100% droplet blocking one would expect water molecules to evaporate from the captured droplets and migrate to the other side of the mask (since molecules are far below filtration size).
That...doesn't tell us much of anything useful.
Moreover, it's in direct contrast to the evidence we have of healthcare professionals wearing masks for multiple hours with strong protection against infection. This is not a good proxy measure.
They appear to be trying hard to conflate this useless measure with a useful measure. From "Discussion":
> "According to our RH transmittance tests, the fast and significant drop in humid air filtering capability demonstrates a rapid functional degradation not specifically related to bioaerosols transmission."
i.e., "our method tells us nothing about protection against viruses, but we'll claim it shows "rapid functional degradation" in order to sound like we've shown masks are bad".
That's actively misleading.
They similarly overclaim in their conclusion to the discussion:
> "As a conclusion we can say that, while it is evident and commonly accepted that wearing a face mask is very important for reducing the virus spread, especially in circumstances where proper ventilation and social distancing cannot be guaranteed, our study underlines that wearing a face mask is really beneficial only if it is used correctly."
Their data does not support that claim.
Their data shows that relative humidity increases after a short time; it does not show that viral transferrence increases after a short time. They keep trying to conflate those two things, but their data does not support that conflation.
Ug - there's an obnoxious amount of conflation and overclaiming in this paper.
Hmm - the paper seems to be injecting a certain amount of bias into the text. From "Discussion":
> "The collected survey data highlight the lack of awareness of the basic principles of single-use face masks"
They do not have the data to make this claim.
In particular, none of the survey questions they asked give them information about awareness of mask use, only actual practice of mask use. It's entirely possible (and likely) that survey respondents were aware that single-use masks are single-use, but chose to re-use them for various reasons (convenience, cost, etc.).
Similarly, from later in "Discussion":
> "This confirms that government rules do not automatically lead to a proper face masks usage by the general population."
Is that a claim anyone has ever made? It reads as a low-effort complaint about government regulation.
All indications are that the paper was written with a specific conclusion in mind rather than as a dispassionate examination of the data.
Thank you for taking the time to write a cogent response to this. Just so many strange scare phrases that don't belong in a scientific study. Like sure, it's probably a good idea to change out a disposable mask somewhat regularly because they get mechanically degraded after many uses, like straps wearing out, or might get gross if you get a bunch of food or mucus on them, but what's with all this hand-wavey "health effects" that they never substantiate? Are we going to start concern trolling about seatbelt skin chafing problems without mentioning car accidents next?
Lots of bunk insinuation, no new insights.
Agreed . The warmer and wetter the better. Someone should start selling pre-moisten masks.
Yea this study is hot garbage.
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I think you've misunderstood the vast majority of what you've read. You're making assumptions about the authors' intent and motivations when there really isn't evidence to suggest those to be the case. For example, it's very clear that they weren't trying to say "masks are bad" as you asserted, and the later statement in no way reads as a complaint about government regulation.
I kind of wonder if you just anticipated that someone could try to use this study to say those things and then subconsciously projected that anticipation onto the authors themselves? Because you've read a lot into this paper that just isn't there.
Edit: I do want to add that your criticism of using RH as a proxy is not included in my comments here...that is pretty reasonable.
> I think you've misunderstood the vast majority of what you've read.
If you would care to quote and discuss specific examples, I would be happy to dig into those. It is always possible that I've misunderstood.
Without anything specific to discuss, though, it's hard to meaningfully address your comment. Vague generalities don't provide much in the way of substance.
> I do want to add that your criticism of using RH as a proxy is not included in my comments here...that is pretty reasonable.
That's...80% of my comment.
80% of the rest was pointing out that they're making unsupported claims based on their survey (awareness vs. practice).
So, yes, there was indeed a small amount of editorializing based on my impressions having read through the paper. I believe I clearly marked those as such, so I don't think that's unreasonable. (As always, though, I could be wrong on that, and am open to specific arguments to the contrary.)
Thank you both for having a civil exchange about COVID masks. This is what we NEED more of.
If you are interested, he is hardly alone in making these criticisms. Check out these comments from when I posted this on a different sub myself.
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