Episode 662: Elliott Gall, PhD - Particle Mitigation Strategies; What Works?

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Episode 662: Elliott Gall, PhD - Particle Mitigation Strategies; What Works?

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Show Resources: Show Discussion:

12:06:37 From Jonathan Faith : Trivia: Name the protective covering of silk or other fibrous substance spun by the larvae of moths and certain other insects as a cover for the pupa?
12:08:01 From Bruce White : Chrysalis?
12:08:15 From Jonathan Faith : sorry incorrect
12:13:48 From Jonathan Faith : Triva Hint: 80s scifi movie
12:14:07 From Victor Cafaro : Ecdysteroids
12:14:22 From Jonathan Faith : sorry incorrect
12:18:02 From donfugler : Cocoon?
12:18:11 From Jonathan Faith : Correct Don!
12:18:56 From User : How does buoyancy affect dispersion/settlement regarding size and time?
12:19:50 From Jonathan Faith : email your address to: czlotnik@cs.com
12:39:57 From User : can we get a copy of this article please?
12:40:32 From Ed Light : Elliott- Your research is very important for establishing levels of filtration which should be used in schools. Would you care to comment on my conclusions with respect to justification for MERV-13 in schools based on health-related evidence: 1. MERV-13 is only supported when there are strong sources of fine particulates outside; and 2. MERV-13 is not supported for reducing COVID transmission.
12:46:34 From Jonathan Faith : https://elliott-gall.medium.com/wildfir ... 961e374238
12:47:48 From Ed Light : Any comments on this current issue at ASHRAE? Gaseous air cleaning is being used to justify reducing ventilation (under the Standard 62 IAQ Procedure) based on based on spot measurements of a few VOCs.
13:04:37 From User : What about using alcohol wipes with charged cloths?
13:09:33 From Tom Martin : Do you think schools will add commercial grade air quality monitors that will measure top 10 parameters of Indoor Air Quality?
13:10:33 From Ed Light : Testing surfaces for contaminants cannot distinguish wildfire residue. Marty King and I developed a much simpler method based on soot/ash patterns visible by optical microscopy.
13:11:08 From User : Hows that work Ed?
13:12:02 From Ed Light : p.s. these were from tape samples
13:13:12 From Victor Cafaro : Very interesting show Happy Earth Day
13:13:21 From Tom Martin : Thank you..
13:13:55 From Radio Joe : thanks everyone
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Re: Episode 662: Elliott Gall, PhD - Particle Mitigation Strategies; What Works?

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Nice to talk with Elliot Gall about particle and gas-phase pollutant mitigation topics today. Everything I learn on this topic makes me think we will be hearing more and more about it. The pandemic and the wildfires are making IAQ more important every day.
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CliffZ
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Re: Episode 662: Elliott Gall, PhD - Particle Mitigation Strategies; What Works?

Post by CliffZ »

I opine that its the little stuff (aka ultrafine particulate, PM 2.5 and gases) that bothers Dr. Elliott Gall.

I like the creative homemade aircleaning device that Elliott and his students came up with. A similar concept is used to remove blown insulation from attics and other areas.

My biggest takeaway was the article that he contributed to along with other IEQ notables which was published in the ASHRAE Journal titled. Interpreting Air Cleaner Data Performance.

It's highly probable that all of us cringed at one or more of the dubious claims made by unscrupulous manufacturers peddling expensive devices as effective preventative measures against Covid. The senior living center where my 93 Mom lives spent $7K on one, and they keep it in the entry foyer.

Restoration firms who have purchased the devices and use them for combatting smoke odors have noticed that when operated in heavy odor and smoke damage situations that the room will have a visual haze.

I plan to distribute their paper to my restoration peers.

Now that their paper has been published discussion of this subject will make a great future episode of IAQradio.


https://www.nxtbook.com/nxtbooks/ashrae ... d=20#/p/20
What led to writing this article? Covid created a surge in the marketing and sales of air cleaning devices resulting in exaggerated claims resulting in confusion in the marketplace due to lack of uniform testing.
What are the key takeaways? These devices fall into 2 categories those that are “subtractive” and those that are “additive”.
A subtractive device is an air cleaner based solely upon mechanical filtration (HEPA filter), adsorption (bulk Activated Carbon) or a combination of both. These devices add nothing to the environment and remove substances from it.
An additive device injects something into the air with the goal that the substance injected will remove something from the environment without leaving anything behind.

This distinction between additive and subtractive technologies is not always a rigid, clear line.

Lack of standardized performance metrics, which limits the ability to compare devices and translate to operation in real occupied spaces;
• Testing in small sealed chambers that can overestimate performance in actual buildings;
• Testing that does not account for control conditions (such as natural decay rates);
• Testing conducted at elevated (or sometimes unreported) concentrations of additive/reactive constituents that might not reflect real-world use;

Z-Man signing off!
• Lack of chemical by-product testing or demonstration of complete oxidation;
• Omission of test parameters, such as chamber volume or mixing conditions;
• Variation in parameters between control and test conditions.
https://elliott-gall.medium.com/wildfir ... 961e374238
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