Hey all,

apologies for sounding the alarm. As I mentioned ,the science is still very unclear on this.
Here's the latest thread from the twitter AQI expert:
https://mobile.twitter.com/marwa_zaatari/status/1439101884229423106
There's a letter at the end warning about the dangers of the unproven ionization technology.

At the same time, here are a couple papers that show removing the ionizer reduces effective CFM of a blueair unit, and also that this group did not detect ozone when using several air purifiers, including a couple blueair models.
https://www.built-envi.com/wp-content/uploads/IIT-CADR-Testing-Blueair-211-August-2021.pdf, https://www.built-envi.com/wp-content/uploads/IIT-CADR-Testing-February-2021.pdf

There's more digging to be done here if anyone feels so inclined.


On Sun, Nov 14, 2021 at 7:44 PM Austin Paul <austinjpaul@gmail.com> wrote:
I actually have a BlueAir 311 I'm not using I'd be happy to bring in to the tower.
2 notes on the BlueAir though:
1. The filters are not officially HEPA, they are something else.
2. The BlueAir products have an ionizing chamber. The goal here is to blast particles out of the air, but the side-effect is creating reactive oxygen species like ozone, things it's better not to breathe. (Then again, it's also maybe not good to breathe the original particles?) The science here is really hard to nail down, with so many studies funded by the air purifier companies. There are guides online about how to take the ionizing unit out, which I would probably try to do. 

Laura had a guide from a Twitter IAQ (indoor air quality) expert that plotted circulation against cost, colored by noise with ionizing units highlighted. It might be informative to pull that up again before we purchase. On the other hand, I have a BlueAir in hand already.

-AP


On Sun, Nov 14, 2021, 18:09 Gregory Russell <gfr10598@gmail.com> wrote:
I'm guessing Advent might be 14 x 14 x 16 (maybe 18), not counting the
vestibule.  Probably want around 250 to 300 cfm.

Looks like a BlueAir 311 or Coway Mighty would be appropriate CFM.
Wirecutter likes both, and looks like they rate Coway higher principally on
price.
BlueAir might be quieter - I didn't find dB ratings for the Coway.

I'd be in favor of going ahead with the BlueAir 311.  I'm happy to order
one and be reimbursed sometime.

On Sat, Nov 13, 2021 at 3:22 PM Cally Perry <cally.perry@gmail.com> wrote:

> We’re pretty happy with our ridiculously quiet Blueair filters, recommended
> by David Wilson that day the air quality dropped into the red here. There
> have since visited multiple venues en masse.
>
> On Fri, Nov 12, 2021 at 6:55 PM John Schreiner <jeschreiner17@gmail.com>
> wrote:
>
> > My envelope calculation says 315 m^3/hr can cycle the air 5 times an hour
> > in a space 15x15x10. 10’ is probably not the ceiling height in your
> > mother’s house, and also not in either tower, but it’s an understandable
> > amount.
> >
> > John
> >
> > On Friday, November 12, 2021, <lauradi@rcn.com> wrote:
> >
> > >    What we have in our bedroom and in two rooms in my mother's house is
> > > this one
> > >
> > > https://www.smarterhepa.com/products/smart-health-s
> > >
> > >   At the lowest level, it's very quiet.  When one looks at the specs,
> it
> > > states that it has a "Clean Air Delivery Rate (CADR) of 315 m3/hr." I
> > think
> > > for maximum virus protection, this is what one is supposed to have per
> > > *minute* not hour, but we're hoping it's better than nothing for
> viruses
> > as
> > > well as allergens.
> > >
> > > Laura Dickerson
> > >
> > > ----- Original Message -----
> > > From: Cally Perry &lt;cally.perry@gmail.com&gt;
> > > To: Austin Paul &lt;austinjpaul@gmail.com&gt;
> > > Cc: Andrew Tyler via Boston-change-ringers &lt;boston-change-ringers@
> > > cosmos.phy.tufts.edu&gt;
> > > Sent: Fri, 12 Nov 2021 16:53:25 -0500 (EST)
> > > Subject: Re: Annual Meeting
> > >
> > > As promised, I sorted out where the square dancers got the idea that
> Hepa
> > > filtration was super useful.
> > >
> > > If you go to the microCovid site  (Google will find it, but this site
> > > strips links), and put in an approximate scenario  (indoors, 10 people
> > > total, 3 feet apart, talking normally, etc., very approximate, but
> > there's
> > > no setting for One Person is Yelling at a time) and select the
> > Environment
> > > menu, one of the dropdowns is "Indoors with a HEPA filter (flow rate 5X
> > > room size per hour) [1/4th the risk]
> > >
> > > I haven't researched the microcovid site, but it does seem as though we
> > > might want to pony up for an air filter.
> > >
> > > Best,
> > > Cally
> > >
> > >
> > >
> > >
> > > On Sun, Oct 24, 2021 at 1:35 PM Austin Paul &lt;austinjpaul@gmail.com
> > &gt;
> > > wrote:
> > >
> > > &gt; Hi everyone,
> > > &gt;
> > > &gt; Our Annual Guild Meeting will be Monday November 8th at 7:30 pm
> > > online (in
> > > &gt; stead of handbells).
> > > &gt;
> > > &gt; I will send out a zoom link closer to the time.
> > > &gt;
> > > &gt;
> > > &gt; Best,
> > > &gt; Austin
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