Wow, that's quite collection of studies within that link! Ideally I'd find something in there with details that pass my sniff test, including the methodology and resulting numbers. That's why I only looked at a couple from your link before, it takes time. But you've sent a lot of information my way. An overwhelming amount, to be honest! I'm not sure how long I'd need to look to find some good specifics. I'm poking around now...

Looking for a critique first, I stumbled found this article listing a bunch of pro-mask studies [2], with summaries. I took a quick peek at #3, which mentioned using laser light to examine droplets being exhaled. Sounded like a neat way to quantify things. As I got into it I wondered about the sizes of viruses in relation to the particles they were measuring. But I read some more and it appears they used a slightly damp washcloth, not a mask. That's the kind of thing that I find discouraging - the article quotes this as one of many studies supporting masks, but it was a damp washcloth! I don't consider that to be valid, and it doesn't help the credibility of the headline in my mind.

Have you got that far into details on any of this? The titles of these studies aren't enough to convince me, especially when I've clicked on several definitively titled studies and they are anything but. Maybe I have bad luck choosing which studies to read.

I went back to your link in the comment above. Under the Exhalation section I looked at this [1] 2020 study, it was the newest. It places a couple hundred people with the flu in cars and bedrooms, with and without masks, and used a device to measure particles in size from 20-1000nm, and found that masks had a significant effect. I then looked to see what size particles spread covid-19 and found this study [2] that mentions 80-90% of particles from human expiratory activities were aerosols with the diameter being smaller than 1μm. I confirmed that 1μm equals 1000nm [3]. They did something else with an aerosol generator and a dryer and a neutralizer, which is kind of confusing, but I think they were just doing some bench measurements. The worst I can say about this study is that the results in Table 2 include a pretty wide variations, and I'm not sure why. For example, in round numbers bedroom background particles were 51K +/- 16k, no mask was 93k +/- 63k, medical mask was 53k +/- 18k. What does it mean that background ranged from 35-67k and no mask from 30-156k? They mentioned these were "in group comparisons", maybe that has something to do with these numbers. I have to assume those aren't error ranges? I didn't see a link to their raw data to know for sure.

So that last study is interesting! It certainly passes my initial sniff tests. I'd save this link if I were you, it's the best I've looked into. At this point I'm curious to keep an eye out for a best conflicting study. Until then I've shifted my opinion, I'm not as sceptical as I was. I'm still not a fan of mask mandates, based on other reasons, but I respect hard data and wouldn't want to argue from an inaccurate position.

[0] https://www.kxan.com/news/coronavirus/do-face-masks-work-her...

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7883189/#mds310...

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7293495/

[3] https://www.traditionaloven.com/tutorials/distance/convert-m...