On Dec 12, 2020, at 1:30 PM, Monona Rossol <0000030664c37427-dmarc-request**At_Symbol_Here**LISTS.PRINCETON.EDU> wrote:

And clearly, the study shows that, even in public, if the wearer of the valved N95 gives a damn about others they'll tape over the inside of the valve which was shown to restore the N95 to almost full efficiency.  And at least it should take the valves out of the DIY masks..   Monona

-----Original Message-----
From: Ray Cook <raycook**At_Symbol_Here**APEXHSE.COM>
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Sent: Sat, Dec 12, 2020 12:56 pm
Subject: Re: [DCHAS-L] NIOSH Technical Report P/N 2021-107: Filtering Facepiece Respirators with an Exhalation Valve: Measurements of Filtration Efficiency to Evaluate Their Potential for Source Control

The public environment was indeed what I was referring to. Superior precautions for the medical environment goes without saying from my perspective.=F0=9F=98=89

Regards,

Ray Cook, MS, CIH 2000-2016

CSP ret.

ApexHSE.com

832-477-4454

I Cor 1:18

In omnia paratus

Sent from my iPhone

On Dec 12, 2020, at 11:15 AM, Monona Rossol <0000030664c37427-dmarc-request**At_Symbol_Here**lists.princeton.edu> wrote:

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My husband recently had an operation for facial skin cancer that turned out to be an all-day affair with a large skin graft.  I mention this because two surgeons an a nurse were "face to face" with my husband repeatedly over the day and part of the time I was in the room as well.  So that particle emission data might be nice to know for lay people, but not for medical personnel.  If those three people in the room with my husband were wearing either surgical masks or valved FFRs, I'd have yanked him outa there and put him together with thread and needle my damn self. They were in N95s and shields for their own and the patient's protection.  The days when surgery is performed by personnel in surgical masks are suspended pending the arrival of the Vaccine Messiah.

Monona

-----Original Message-----
From: Ray Cook <raycook**At_Symbol_Here**APEXHSE.COM>
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Sent: Sat, Dec 12, 2020 7:50 am
Subject: Re: [DCHAS-L] NIOSH Technical Report P/N 2021-107: Filtering Facepiece Respirators with an Exhalation Valve: Measurements of Filtration Efficiency to Evaluate Their Potential for Source Control

I find this paragraph very interesting.

If I read it correctly and avoid confirmation bias, it sounds as though wearing a valved N95 can be as or more effective at source control than the current masks & other items worn by the public, all while actually protecting the wearer to a much higher degree. 

"Even without mitigation, FFRs with exhalation valves can reduce 0.35-=CE=BCm MMAD particle emissions more consistently than surgical masks, procedure masks, cloth face coverings, or fabric from cotton t-shirts; however, the 0.35-=CE=BCm MMAD particle emissions are not expected to be lower for every model."

So in my opinion, there should be no restrictions against wearing these, such as those being applied by various companies & govt entities. I'll be curious to see if they are lifted, but somehow I an not optimistic.

Confirmation bias creates a strong motive for dismissing information inconsistent with popular opinions.

Regards,

Ray Cook, MS, CIH 2000-2016

CSP ret.

ApexHSE.com

832-477-4454

I Cor 1:18

In omnia paratus

Sent from my iPhone

On Dec 12, 2020, at 4:46 AM, John Callen <jbcallen**At_Symbol_Here**gmail.com> wrote:

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ALL,

The subject study is "hot-off-the-press" and is worthy of your consideration.

SUMMARY: https://www.cdc.gov/niosh/docs/2021-107/default.html

This summary has PDF Link so you can read the entire report (attached below).

REPORT: https://www.cdc.gov/niosh/docs/2021-107/pdfs/2021-107.pdf?id=10.26616/NIOSHPUB2021107

The Bottom Line : "These finds have important implications for guidance on source control and mitigation."

It maybe possible that this will open up a blocked avenue of RPE.

After review, I certainly welcome your comments.

Be Safe and Stay Healthy!

All My Best and Happy Holidays,

John B. Callen, Ph.D.

3M Personal Safety Division - Retired

ACS/DCHAS Founding Member

(312) 632-0195

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