[ARC5] AB5S Kung Flu Update, 13 June - source?

Sun Jun 14 14:54:47 EDT 2020

That pretty much aligns with my view, Scott, with the addition of 
information from an interesting study about aerosols produced by simply 
"normal" talking, reported at 
https://www.nytimes.com/2020/05/14/health/coronavirus-infections.html 
(The National Academy of Sciences detailed report is at 
https://www.pnas.org/content/117/22/11875 ).

The gist of the article was:
"To see how many droplets are produced during normal conversation, 
researchers at the National Institute of Diabetes and Digestive and 
Kidney Diseases and the University of Pennsylvania, who study the 
kinetics of biological molecules inside the human body, asked volunteers 
to repeat the words “stay healthy” several times. While the participants 
spoke into the open end of a cardboard box, the researchers illuminated 
its inside with green lasers, and tracked bursts of droplets produced by 
the speaker.

The laser scans showed that about 2,600 small droplets were produced 
_per second_ while talking. When researchers projected the amount and 
size of droplets produced at different volumes based on previous 
studies, they found that speaking louder could generate larger droplets, 
as well as greater quantities of them.

Although the scientists did not record speech droplets produced by 
people who were sick, previous studies have calculated exactly how much 
coronavirus genetic material can be found in oral fluids in the average 
patient.  Based on this knowledge, the researchers estimated that a 
single minute of loud speaking could generate at least 1,000 
virus-containing droplets."

Here's a picture of the test setup:

That makes it even more than a courtesy to wear a mask, especially since 
most coronavirus spreaders aren't even aware when they are in the early 
stages of their infection.  The cloth masks are indeed not perfect, but 
they are only intended to reduce the frequency of the much larger 
droplets, not the much smaller virus which is attached to them.

- Mike  KC4TOS

On 6/14/2020 2:00 PM, Scott Johnson wrote:
> I consider the primary reason for masks, or bandanas, or whatever, not to
> protect yourself, but to protect other from you.  It is a courtesy, if you
> sneeze, cough, or slobber when you talk, it effectively prevents the aerosol
> from going further than the fabric.  Not wearing anything in proximity to
> the public identifies one as  careless and reckless.  If you are in a high
> risk group, and truly worried about your own safety, then you shouldn't be
> exposing yourself needlessly.  I have heard so many opinions, some that are
> diametrically opposed, and all from supposed experts.  Don't care to hear
> any more. Common sense coupled with common decency should prevail.  BTW, one
> of my engineers did a CFD model in Solidworks of a sneeze in a room with
> closed loop HVAC.  It propogates and dissipates pretty much like a fart.
>
> Scott V. Johnson W7SVJ
> 5111 E. Sharon Dr.
> Scottsdale, AZ 85254-3636
> H (602) 953-5779
> C (480) 550-2358
> scottjohnson1 at cox.net
> scott.johnson at ieee.org
>
> -----Original Message-----
> From: arc5-bounces at mailman.qth.net <arc5-bounces at mailman.qth.net> On Behalf
> Of Hubert Miller
> Sent: Saturday, June 13, 2020 11:21 PM
> To: arc5 at mailman.qth.net
> Subject: Re: [ARC5] AB5S Kung Flu Update, 13 June - source?
>
> Generally good advice, but I question the non-cough non-sneeze 26 foot
> business, no matter what your doctor said.
> I have read several articles in the New York Times precisely on this
> question, and those articles are well informed, very well informed,
> frequently updated. Ask your doctor his source for his information. I recall
> now they also had an article comparing actual effectiveness of different
> kinds of masks, both homemade and commercial, and gave actual numbers
> compared to N95, and what thickness required even with homemade.
> Also, masks are dry material, so what is your informed reckoning of how long
> virus lives on them ?
> As for health professionals dying despite masks, well, you would have to
> know the extent of their exposure and their full suiting equipment to assign
> this to mask inefficiency.
> Don't forget UV exposure either, to kill virus. These parameters apply
> outside also.
> I found Elderberry anything to be pretty much sold out locally last time I
> shopped, but I'll take another look in the next days.
> -Hue Miller
>
>
>
>
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: https://www.qsl.net/donate.html
>
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: https://www.qsl.net/donate.html

-- 
Michael Hanz - KC4TOS

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/arc5/attachments/20200614/d37ac7bc/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: VIRUS-DROPLETS.jpg
Type: image/jpeg
Size: 32192 bytes
Desc: not available
URL: <http://mailman.qth.net/pipermail/arc5/attachments/20200614/d37ac7bc/attachment-0001.jpg>