On Lockdown

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Smokedaddy
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Re: On Lockdown

Post by Smokedaddy »

... well my 2 cents. I think expelled particles are dispersed by airborne and/or droplet transmission and the particle size can be a small as 50nm. I think the typical masks being worn by the general public are highly ineffective at stopping particles. Not only from the poor fit but the material being used. Even the N95 mask is only tested for stopping particles 300nm and larger 95% of the time and that's with a 100% medical fit test. The general public doesn't have access to those mask and even if they did they would probably only be 60% effective for 300nm particles (just guessing of course) due to improper fit and farting around with their mask. I believe that soon they'll have scientific proof of COVID-19 airborne characteristics and properties. I'm not saying that mask are useless but they pretty much are if the particles end up being in the 50nm category.

Lou Jost
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Re: On Lockdown

Post by Lou Jost »

Smokedaddy, I think you are missing the main purpose of masks in the general population. Masks are not primarily to protect the wearer but to protect the people around the wearer. Masks clearly reduce the velocity of air escaping the mouth, so they reduce the mean distance of aerosol travel. That is just physics, and does not require the mask's mesh to be as tight as an N-95 mask.

In the US, a large segment of the population now argues that it should be up to the individual whether he or she should wear a mask in public. The short argument they usually give is that they are willing to take the risk of getting sick, and so should not be obligated to wear one. This argument is wrong. The reason for obligating people to wear masks is the same as the reason people in civilized countries are forbidden to defecate in the streets. The reason is to protect the rest of society from serious contagious disease.

Regarding the studies I linked to, there is surveillance video of the restaurant episode. The article says that the spreader "later that night, the person showed symptoms." The phrasing of this suggests that it might not be based on self-reporting. The authors could have seen that the spreader did not cough. The article footnotes two original studies of the incident and its video evidence, but the citations don't appear in the internet article. It would be interesting to see them.

The distinction between symptomatic vs asymptomatic spreaders (which as Rik notes, has no relation to the term "superspreader") is relevant to the mask argument, because some argue that one only needs to wear a mask if they show symptoms.

Smokedaddy
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Re: On Lockdown

Post by Smokedaddy »

For starters I'm not in the 'wear no mask' group, nor am I virologist etc. I understand the main point for wearing a mask. Keep in mind that Fauci even said in a interview wearing a mask isn't that effective. I think COVID is airborne therefore floats in the air longer, is smaller due to particle dehydration than originally thought. To me that makes mask less effective especially since they're usually worn incorrectly. I'm also not arguing just conveying my reasoning.

Lou Jost
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Re: On Lockdown

Post by Lou Jost »

Sorry, I didn't understand what you were arguing in your previous comment. It seems to me (just based on physics) that no matter how fine the aerosol, masks muffle the expulsion distance, reducing the movement of particles to something like passive diffusion. Masks should be useful, then, regardless of the fineness of the aerosol, except for cases in which you are stuck for a significant amount of time in a close space with someone infected. In that case, if you wait long enough, I agree with you that diffusion could create a high enough concentration of aerosol droplets, and home-made masks won't help much (except to buy more time for the person).

Smokedaddy
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Re: On Lockdown

Post by Smokedaddy »

... and that's my point. From what I've read (not Facebook) if airborne (note the if) particles can float for hours depending on particle size, just like particles do in a semiconductor clean room environment. If that's the case and COVID particles are smaller than 300nm, then even N95 type mask with a 100% end-user seal their efficiency drops more than rated. I can't fathom the inefficiency of some of the mask being sold to the public, especially when they first started making them. Plus the poorly fit ones I've seen, those wearing them incorrectly to begin with and constantly farting around with them. So to some degree a mask discourages possible COVID exhausted particles. That should be obvious but how effective are mask from inhaling super small, lets say 200nm (or so) airborne COVID particles through or around ill-fitted non N95 type mask. That's my question and concern. To this very day the entire conversations and debate regarding COVID is still up in the air scientifically.

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dolmadis
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Re: On Lockdown

Post by dolmadis »

Smokedaddy wrote:
Fri Jul 10, 2020 10:48 am
... and that's my point. ............... To this very day the entire conversations and debate regarding COVID is still up in the air scientifically.
In Nature...............................https://www.nature.com/articles/d41586-020-02058-1

Lou Jost
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Re: On Lockdown

Post by Lou Jost »

That should be obvious but how effective are mask from inhaling super small, lets say 200nm (or so) airborne COVID particles through or around ill-fitted non N95 type mask. That's my question and concern.
Sure, thats a valid concern, but as I keep saying (and I thnk you agree), protecting the wearer is not the main function of masks for the general public. We know for sure that they do work for what they are intended to do, reducing the risk of the wearer's aerosols from reaching other people. This is a physics problem.
To this very day the entire conversations and debate regarding COVID is still up in the air scientifically.
There are many things we don't understand, but we do know some things.

Smokedaddy
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Re: On Lockdown

Post by Smokedaddy »

A few of the items I was reading about mask. Of courses there are many more that I've read, even from the CDC site, some of which were concerning on the mask testing protocol.

https://www.medpagetoday.com/infectious ... illness%20(6.7%25

https://www.medpagetoday.com/HospitalBa ... orce/15518

https://www.cidrap.umn.edu/news-perspec ... n1-setting

-JW:

Lou Jost
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Re: On Lockdown

Post by Lou Jost »

Those articles mainly focus on the question of protecting the wearer. I agree that there is not strong evidence that they protect the wearer. The great importance of masks is to reduce the transmission rate from a possibly-infected wearer to other people.

ray_parkhurst
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Re: On Lockdown

Post by ray_parkhurst »

rjlittlefield wrote:
Thu Jul 09, 2020 9:55 pm
I don't understand why you write "would find it odd". I see nothing in the article to suggest that the epidemiologist was surprised. What have I missed?
I was just referring to the "super-spreader" designation, which I believe qualifies as "odd" from epidemiological perspective.
Lou Jost wrote:
Fri Jul 10, 2020 6:46 am
Masks clearly reduce the velocity of air escaping the mouth, so they reduce the mean distance of aerosol travel.
Ironically, many masks have ventilators that actually increase the velocity of the exhaled air. I went shopping at a health food store in Santa Cruz recently, and found that Santa Cruz County has apparently outlawed masks with ventilators, presumably for this reason. I wore an N95 to the store, and was politely asked if it was OK for the attendant to tape over my ventilator! Uh, no thanks, I'll just bring a mask without the ventilator next time!

Rasputin's Music in Campbell opened up this week, and I went there today for first time shopping for movies since mid-March. I was in the store for almost an hour! The cool thing was that they were monitoring customers coming in for temperature. I measured 97.1F, so they let me in. It was my first time having temperature measured, and I was very glad to see this happening.

Lou Jost
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Re: On Lockdown

Post by Lou Jost »

I'm glad you were able to go out. Yes, masks with ventilators definitely defeat the main purpose of the mask nowadays, community protection, though of course they are great when using the mask to keep from inhaling toxic dust or particles.

Temperature-checking is reassuring, but there are still asymptomatic people to worry about.

Beatsy
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Re: On Lockdown

Post by Beatsy »

If you wear glasses and are required to wear a face mask, you might be entitled to condensation.
Last edited by Beatsy on Sun Jul 12, 2020 7:01 am, edited 1 time in total.

Lou Jost
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Re: On Lockdown

Post by Lou Jost »

=D> :D

ray_parkhurst
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Re: On Lockdown

Post by ray_parkhurst »

Lou Jost wrote:
Sat Jul 11, 2020 7:58 pm
I'm glad you were able to go out. Yes, masks with ventilators definitely defeat the main purpose of the mask nowadays, community protection, though of course they are great when using the mask to keep from inhaling toxic dust or particles.

Temperature-checking is reassuring, but there are still asymptomatic people to worry about.
Yes, but depending on whom you believe, the asymptomatic folks may be far less contagious than symptomatic folks. But of course there may be far more of them...

ray_parkhurst
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Re: On Lockdown

Post by ray_parkhurst »

I have been sorting through news stories, data, and some reports, but I can't seem to decipher what the true results are from the "reopening". My state of CA just canceled some of the reopenings, and I expect more "second wave shutdowns" to happen. But I can't find any non-politicized data or information that I can trust. I feel like we're in the "fog of war" at the moment. Does anyone have any real information they can share? I mean real, verifiable, objective info? I've seen and heard so much from all sides that I really don't know what to believe. Initially I downplayed the increase in cases as simply a byproduct of increased testing, and reports of a decrease in the number of deaths (and thus a large decrease in CFR) were encouraging, but now I'm hearing the deaths are increasing again, and that more young people are succombing. Unfortunately I don't have counts to see if this is true or just propaganda.

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