Skip to content

I need some sort of letter and tactics to overcome objections.

    Here’s such a letter.

    • It addresses
      • Air cleaner efficacy in general, and the Corsi/Rosenthal Box, in specific.
      • HVAC infrastructure concerns (it will not cause issues).
      • Electrical concerns (will not cause fires).

    How to use such a letter? Possible ideas:

    • Just emailing it to the concerned individual.
    • Better would be to find parents “…who have working relationships with district admin and/or school board members? It helps to meet with them or call them individually. I sent a letter to our superintendent and cc’d the admin folks I know. They are working on getting CR boxes now.” (Quote from DaleAnn Baker.)

    How NOT to use such a letter? Some people are all about videos. That’s ok – meet them where they are at.

    What if you experience push-back after the letter, or you anticipate a hard push-back? Sometimes, it helps to gather evidence of poor ventilation.

    • Get a CO2 monitor like an Aranet. Put it in your kid’s backpack pocket (this twitter thread has some ideas) – ideally, you want it where your kid is.. Track the ventilation for a couple of days. (Very important – HEPA/ DIY air cleaners will NOT lower CO2, as gas molecules are too small to be captured by the filters.).
    • What is the value of measuring CO2? This excellent Washington Post article , posted at (so all can read it), explains all.
    • If the CO2 is showing as high, then you can present that as an indicator of the ventilation as being insufficient.
      • What is considered high? Above 920 ppm (or 500 above baseline).
        • This is discussed by Dr. Dustin Poppendieck here.
          • Prepandemic times:
            • For 24 students & 1 teacher, roughly 550 ppm over the outside air (usually 420 ppm – you can find this just by putting the CO2 monitor outside the classroom). So, 970 ppm.
            • For 34 students & 1 teacher, roughly 900 ppm over outside air (1320 ppm).
            • But these are NOT those times.
        • Pandemic Recommendations – roughly 500 max over baseline. 920 PPM in most locations.
          • The Belgian Government recommends no more than 900 PPM total – so roughly 400 to 500
          • Harvard Healthy Buildings initiative (Page 27, 5-6 ACH is roughly 920 PPM as per Dr. Poppendieck).
    • Some Talking points, from this spreadsheet developed by David Elfstrom., as discussed here.
      • At 800 PPM (Parts Per Million), 1% of what everyone breathes is from other people’s lungs – which might have Covid in them. (Though some of it would be from your own lungs.).
      • At 1000 PPM, 1.5%
      • At 1200, 2.1%.
      • At 1500, 3%
    • Dr. Linsey Marr, respiratory virus transmission/aerosol scientist tracked the CO2 in her school. Make sure to read the comments.
    • Additional Resources on this topic:

    Did you find this FAQ helpful?
    Thumbs Up Icon 2
    Thumbs Down Icon 2