On 26 Jun 2020, at 18:11, Monona Rossol <0000030664c37427-dmarc-request**At_Symbol_Here**lists.princeton.edu> wrote:
=EF=BB=BF--- For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchasOoops. 4-5% = 40,000 - 50,000 ppm. lungs are REALLY good at exchanging gases apparently. Monona
-----Original Message-----
From: Monona Rossol <0000030664c37427-dmarc-request**At_Symbol_Here**LISTS.PRINCETON.EDU>
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Sent: Fri, Jun 26, 2020 12:25 pm
Subject: Re: [DCHAS-L] Sars-CoV2 infectivity
Hmm. 0.04% = 400 ppm (world average now) and 4-5% is 4000-5000 ppm, soooo, when they exhale 3500 ppm CO2 that's about right. Monona--- For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchas
-----Original Message-----
From: Backus, Bruce <backusb**At_Symbol_Here**WUSTL.EDU>
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Sent: Fri, Jun 26, 2020 11:39 am
Subject: Re: [DCHAS-L] Sars-CoV2 infectivity
Hi Ralph,
Is that breathing directly into a CO2 meter, or analyzing the air in the breathing zone under a mask? The air we breathe in contains about 0.04% CO2, but we exhale air that contains about 4 to 5% CO2.
Thanks,
Bruce
_____________________________________
Bruce Backus
Assistant Vice Chancellor | Environmental Health and Safety | Washington University in St. Louis
4533 Clayton Ave.| Campus Box 8229 | Saint Louis, MO 63110
S: 314.362.8976 | Cell C: 314.302.0466 | : backusb**At_Symbol_Here**wustl.edu
-----Original Message-----
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Stuart, Ralph
Sent: Friday, June 26, 2020 9:55 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] Sars-CoV2 infectivity
> 900 to 1000 ppm CO2 is also where documented effects on mental acuity can be shown. It's a nice number.
Is there a reference for this? I just had one of our librarians who had been wearing a cloth mask for an hour exhale into a CO2 meter and he hit 3500 ppm. After wearing a cloth mask for 20 minutes, I max out around 1500, so I suspect that the longer wearing periods could become productivty problem.
- Ralph
Ralph Stuart, CIH, CCHO
Environmental Safety Manager
Keene State College
603 358-2859
ralph.stuart**At_Symbol_Here**keene.edu
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