I understand that it's a respiratory illness that is most often spread after someone coughs or sneezes. But this is mostly through heavier droplets that fall rather quickly onto ... surfaces. So that you may still be more likely to get it by touching a contaminated surface and then touching your face before washing your hands than your are by breathing it in.

I agree that masks will improve safety even further. But there has to be a reasonable limit to this. Wearing a mask even though your maintaining six feet distance makes sense up to a point. For a neighbor to worry because I wasn't wearing a mask when outdoors even though I was 50 or so feet away from him, in a steady breeze and minutes after it had rained is ridiculous.

I found this part of that paper interesting:

"Among the samples collected without a face mask, we found that the majority of participants with influenza virus and coronavirus infection did not shed detectable virus in respiratory droplets or aerosols, whereas for rhinovirus we detected virus in aerosols in 19 of 34 (56%) participants (compared to 4 of 10 (40%) for influenza and 8 of 23 (35%) for coronavirus). For those who did shed virus in respiratory droplets and aerosols, viral load in both tended to be low (Fig. 1). Given the high collection efficiency of the G-II (ref. 19) and given that each exhaled breath collection was conducted for 30 min, this might imply that prolonged close contact would be required for transmission to occur, even if transmission was primarily via aerosols, as has been described for rhinovirus colds20. Our results also indicate that there could be considerable heterogeneity in contagiousness of individuals with coronavirus and influenza virus infections."

Now then, that's a different "coronavirus" they're talking about there (i.e. not Covid-19), but still...kinda implies the wearing a mask thing as being pretty far down on the "diminishing returns" list for something to do for prevention from incidental "close passing" I'm thinking.

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http://bikeblather.blogspot.com/

Yeah, but over what time frame? That preliminary German study alluded to earlier didn't find any cases from incidental exposure at things like shopping or going to the hairdresser even. The majority came from a bunch of people being in close contact for quite a long time at a "carnival" event in the city.

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http://bikeblather.blogspot.com/

That's true, and the same I've gathered from other sources. But there might be ancillary benefits to mask-wearing, e.g. when you have one on it's a convenient device to protect against accidental/unconscious touching of your own face. Like if you want to scratch your nose or something, it forces you to think about it, which then provides an opportunity to do it in a safe way.

So it may offer some protection not only against doing from aerosol, but from incidental direct physical contact.

Clear glasses (or any glasses) might help with eye-rubbing.

Interesting aside...I came across a friend of mine last week who had started wearing a mask when outside. I was struck by how often he kept touching the deformable "nose bridge" piece as we talked and I was thinking "so much for it keeping you from touching near your eyes" ;-)

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http://bikeblather.blogspot.com/

People adjust their masks often, not to mention that most touch their faces (and the potentially infected mask) when they take them off or put them on. I see people walking around with masks down around their chin or below their noses, and I see people taking them down (touching their faces) to use the facial recognition on their phones.

Unfortunately, masks are going to become the latest measure of moral righteousness among a certain portion of the population.

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Slowguy

(insert pithy phrase here...)

And not wearing them will be a measure of moral righteousness among another portion. :)

I see a use, though, just in a purely symbolic way. Wearing one is signalling to people around you, "I think public health is important." Some indication that the person is going to give you space, not going to cough into their hand, etc.

I can't wait to see what's going to be put in place for me to be able to go back to work at our office. It probably will require the wearing of a mask of some sort...

As far ask mask use for being out in public at the store, etc....so far everyone seems fine with me just using my cycling "neck gaiter", even though I know it basically doesn't block anything :-/

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http://bikeblather.blogspot.com/

The Heinsberg study (which is ongoing - see Facebook "Heinsberg Protokoll") had some preliminary results where they had gone into households with active Covid-19 infections of the families. They swabbed various surfaces all around the households, and although they were able to find virus in the samples, NONE of them yielded a viable culture. That "real world" sample tends to indicate the infectiousness on surfaces outside lab conditions might be fairly low. I also recall seeing a TV report early on in the New York experience, where a local news team went around and swabbed a number of public surfaces in one of the "hotspot" areas...everything from door handles to the push level on an alcohol sanitizer dispenser, and they didn't find anything either.



It's easy to implement, and it makes people feel better...but, in reality, the effectiveness of the PPE is only as good as the care taken in using it. That figure 2 is (I'm assuming, since it's a literature review) in respect to subjects that were trained hospital employees, right?

Based on what I've seen, and the training I've had in various PPE, I have zero confidence the general public can consistently use PPE properly.

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http://bikeblather.blogspot.com/

Well, if it functions obviously like a door, open and shut, why would you need a study to know how it works? I don't know how N95 mask works nor have I opened one myself, but I find your argument to be for argument sake.

Because masks aren't as simple as they seem. One of the biggest differentiators in performance, from what I've read, is how well they seal the face. The quality of face seal tends to outweigh differences in filter material. With exhalation pressure being one of the biggest factors that can break a decent seal. So a valve may increase the quality of the seal, on average. The exhalation through the valve may dissipate droplets in some way vs. no-mask exhalation.

We don't know.

I'm guilty of this at times, too, but when it comes to important stuff like this, I think it's important to let the professionals make the call. Not many of us here are qualified to judge the performance qualities of masks.