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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