[FRIAM] preprint aerosol covid

Wed Jan 12 12:41:03 EST 2022

"I wonder how many of us are back in lockdown and aren’t telling each other?"

If it were just me, I wouldn't bother.   I'd probably just roll the dice and consider it my 4th booster.   But we're in lockdown due to the use of a certain monoclonal antibody treatment that destroys B-cells.  Haven't been to the grocery store since March 2020.  I even question the wisdom of risking going to get a PCR test in a public space.   Even some sidewalk or outdoor mall cafes have seating that ends up being less than six feet from the pedestrians.   And the buildings limit the movement of air.   Well, we're not doing it anymore.   I hear the Whole Foods near us is just full of shopper agents, and few normal customers.

In some ways it is good, one can get interviews in companies and cities that would otherwise not consider remote workers.   In another way, it requires a lot of confidence and tolerance for risk to carry on in a direction of work that gets little or no feedback.    It seems to me tech has been really, resilient to this change in lifestyle.

Marcus
________________________________
From: Friam <friam-bounces at redfish.com> on behalf of thompnickson2 at gmail.com <thompnickson2 at gmail.com>
Sent: Wednesday, January 12, 2022 10:20 AM
To: 'The Friday Morning Applied Complexity Coffee Group' <friam at redfish.com>
Subject: Re: [FRIAM] preprint aerosol covid

I wonder how many of us are back in lockdown and aren’t telling each other?

Or, how many of us think we should be in lock down, but aren’t.   This little voice keeps saying to me (you know, my “inner” voice) “Nick.  This omicron thing is going to be terrifying for the next six weeks and then be gone.  The hospitals are going to be jammed.  Not a time to risk any kind of medical emergency, let alone COVID.  Stay home.  Avoid icy pavements.  No sneaking off for coffee.”

If Marcus is worrying about transmission in parks, maybe that time  has come.

Nick Thompson

ThompNickSon2 at gmail.com<mailto:ThompNickSon2 at gmail.com>

https://wordpress.clarku.edu/nthompson/

From: Friam <friam-bounces at redfish.com> On Behalf Of Marcus Daniels
Sent: Wednesday, January 12, 2022 11:03 AM
To: friam at redfish.com
Subject: Re: [FRIAM] preprint aerosol covid

Yesterday I was feeling nervous about being in the park.  It was super still but also high humidity.  Are people wearing masks outside?  This makes me think I should again?

Marcus

________________________________

From: Friam <friam-bounces at redfish.com<mailto:friam-bounces at redfish.com>> on behalf of glen <gepropella at gmail.com<mailto:gepropella at gmail.com>>
Sent: Wednesday, January 12, 2022 9:59 AM
To: friam at redfish.com<mailto:friam at redfish.com> <friam at redfish.com<mailto:friam at redfish.com>>
Subject: Re: [FRIAM] preprint aerosol covid

Yeah, I enjoyed the closed rooms at lockheed. But only the 60Hz ones. The 400Hz rooms were horrible. If the results check out, it spells trouble for me, though, hanging out in breweries ... which usually have higher than normal relative humidity. Stupid virus.

On 1/12/22 08:56, Marcus Daniels wrote:
> We have enough air purifiers to filter the air in the house six times an hour.  It reminds me of the days when I had bitcoin miners running.
> The noise is like being in an airplane all the time.   I rather like fan noise though.   I could sleep in a machine room.
>
> Marcus
> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> *From:* Friam <friam-bounces at redfish.com<mailto:friam-bounces at redfish.com>> on behalf of glen <gepropella at gmail.com<mailto:gepropella at gmail.com>>
> *Sent:* Wednesday, January 12, 2022 9:25 AM
> *To:* friam at redfish.com<mailto:friam at redfish.com> <friam at redfish.com<mailto:friam at redfish.com>>
> *Subject:* [FRIAM] preprint aerosol covid
> The Dynamics of SARS-CoV-2 Infectivity with Changes in Aerosol Microenvironment
> https://www.medrxiv.org/content/10.1101/2022.01.08.22268944v1 <https://www.medrxiv.org/content/10.1101/2022.01.08.22268944v1>
>> Understanding the factors that influence the airborne survival of viruses such as SARS-CoV-2 in aerosols is important for identifying routes of transmission and the value of various mitigation strategies for preventing transmission. We present measurements  of the stability of SARS-CoV-2 in aerosol droplets (∼5-10µm equilibrated radius) over timescales spanning from 5 seconds to 20 minutes using a novel instrument to probe survival in a small population of droplets (typically 5-10) containing ∼1 virus/droplet. Measurements of airborne infectivity change are coupled with a detailed physicochemical analysis of the airborne droplets containing the virus. A decrease in infectivity to ∼10 % of the starting value was observable for SARS-CoV-2 over 20 minutes, with a large proportion of the loss occurring within the first 5 minutes after aerosolisation. The initial rate of infectivity loss was found to correlate with physical transformation of the equilibrating droplet; salts within the droplets crystallise at RHs below 50% leading to a near instant loss of infectivity in 50–60% of the virus. However, at 90% RH the droplet remains homogenous and aqueous, and the viral stability is sustained for the first 2 minutes, beyond which it
> decays to only 10% remaining infectious after 10 minutes. The loss of infectivity at high RH is consistent with an elevation in the pH of the droplets, caused by volatilisation of CO2 from bicarbonate buffer within the droplet. Three different variants of SARS-CoV-2 were compared and found to have a similar degree of airborne stability at both high and low RH.

--
glen
Theorem 3. There exists a double master function.

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