HomeMy WebLinkAbout040323 RE_ Ordinary HEPA filters do not affect CO2 levels________________________________
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Thank you, Tom, for catching that. HEPA filters are a good addition when you get to CO2 concentrations above 1000 but less than 3000, because during that space the CO2 measurement is
really a proxy for stagnant air, rather than the primary danger itself. The HEPA filter is assisting the removal of particulates, viruses, mold, etc. from the air, which become a bigger
problem when the air is stagnant. But you are absolutely right, a HEPA filter would not remove the CO2 from the air, so if the person posing the question really is seeing CO2 levels
higher than 10,000, they need to do larger engineering modifications to change that – primarily interrupting combustion exhaust that may be entering the airspace, and improving the
entry of outdoor air.
Thanks for the close listen. I’m not on the radio for another month, but perhaps one of our commissioners could set the record straight.
Thanks all,
Allison Berry, MD MPH (she/they)
Health Officer for Clallam and Jefferson Counties
allison.berry@clallamcountywa.gov
From: Tom Thiersch <tprosys@gmail.com>
Sent: Monday, April 3, 2023 12:23 PM
To: BoCC - Jefferson County Board of Commissioners <jeffbocc@co.jefferson.wa.us>
Cc: Berry, Allison <allison.berry@clallamcountywa.gov>; WBence@co.jefferson.wa.us
Subject: Ordinary HEPA filters do not affect CO2 levels
Folks,
During the monthly health update in the BoCC meeting on Monday (April 3), both Dr. Berry and Mr. Bence said that HEPA filters could be used to address excessive levels of CO2.
The “P” in HEPA stands for Particulate: High Efficiency Particulate Air.
By definition, ordinary HEPA filters deal only with particulates, not gases like CO2, CO, NOx, SO2, etc.
If the filter has an activated charcoal feature, it will adsorb many VOCs, CO, NOx, SO2, etc., but it will not reduce CO2 levels. For that, you need a CO2 scrubber, and these are not
common in consumer-level appliances.
I would like to hear the BoCC, and KPTZ, clarify this so that people aren’t led into a false sense of security or waste their money buying an inadequate or inappropriate appliance.
Thank you,
Tom Thiersch