Marwa Zaatari Profile picture
Feb 9, 2021 17 tweets 5 min read Read on X
My school installed an electronic air cleaner system (EAC), what should I do?
1) Ask for the following (part 1):
-Make/model of the system
-What is the basis to choosing the number of units? How many units is needed for the airflow, number of people, ft2?
- How do we verify it is working after it is installed?
Ask for the following (part 2)
- Efficiency test data that correspond to the install (in-room versus duct?)
- By-products test (formaldehyde, ultrafine particles, ozone) test at the SAME conditions of the efficiency test.
2) There is a good chance that you will not receive any answer.
--> Very important to focus on pushing for other proven remedies: outside air, central filters, and HEPA purifiers not only to help with COVID and also to help decrease concentrations of by-products produced.
3) Understand what is EAC?

Lots of names:
•Photocatalytic Oxidation (PCO), UV PCO
•Photocatalytic Activation
•Ionization
•Bi-polar ionization (BPI)
•Needlepoint ionization
•Plasma
•Hydro-Peroxide plasma
•NCCO (Nano Confined Catalytic Oxidation)
•Activated Oxygen
More names:
•Surface irradiation
•High voltage coronas
•Hydroxylation
•UV Sanitizer + negative ions
•Cold catalyst filter
•Ionic purifier + composite catalyst
•Fragrance Sponge
•Plasma wave
Lots of names...But the mechanism is the same:
Technologies utilize various methods to create reactive ions in air that react with airborne contaminants.
The design of the systems create mixtures of reactive oxygen species (ROS), ozone, hydroxyl radicals, superoxide anions.
Why so many names?
1.No industry rules for product names
2.Each vendor wants to appear different
3. When a certain technology is disproven, the vendor comes up with a new name
Chemistry Fact 1: Free radicals and/or ozone produced Image
Chemistry Fact 2: Indiscriminate and unpredictable reactions Image
4) Understand what does the science tells us?
Study 1: ww2.arb.ca.gov/sites/default/…
LBL showed that EACs increase VOCs, formaldehyde or ozone. Notice that some of them did not increase ozone but increased formaldehyde and other VOCs.

Red number show increase of pollutant levels! Image
Study 2: CDC/FEMA study
cdc.gov/air/trailerstu…
Safe level of ozone outdoors < 50 ppb. Indoors level of ozone should not be more than 10 ppb. Image
Study 3: NY Department of Health Study
1. Operating the Bipolar ionization unit in the classroom coincided with an increase of the indoor ozone concentration by more than double.
2. Ultrafine , formaldehyde, acetone and acetaldehyde all increased. Image
CDC Position Image
ASHRAE Position regarding technologies that produce hydroxyl radicals:
ashrae.org/file%20library… Image
An open letter regarding the use of ionizers, UV-PCO, DHP, etc. 👇🏼👇🏼

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More from @marwa_zaatari

Nov 1, 2022
🧵A brave and courageous high-level sales executive at GPS (company suing me) provided explosive, truly extraordinary information detailing astoundingly poor conduct on behalf of the highest levels of GPS’s exec team.

🔥Details GFM page: gofund.me/94af426a

(1/7)
Examples of what the employee told me:

1) The results were fabricated for financial gain.

(2/7)
2) If we [GPS] sold the truth, we [GPS] would never have sold at the rate that we were selling, not at 20 times the rate we were experiencing.

(3/7)
Read 9 tweets
Oct 29, 2021
Ventilation air,
Ventilation air,
Where are you?

🧵 Hotel and COVID-19 part 2.

You can find Part 1 here 👇 (still waiting for lab results - 1 more week).
@DavidElfstrom
This week, I stayed at an hotel and this time I came prepared.

Here are some observations about shared air, system type, filtration, and outside air rates.
Air conditioning system type = fan coil unit = fan + filter + cooling and heating coil.

➡️This system does not introduce any outside air. It only filter the air in the room by recirculating it through a filter then a coil then supplying back to the room. ImageImage
Read 11 tweets
Oct 14, 2021
🧵The search for ventilation.
Hotel & COVID-19 Edition.

I stayed yesterday at brand name hotel. Here are some observations about shared air, outdoor air, and maintenance issues.
The room I stayed in does not have shared air. This is typical for hotel rooms. Air in your room gets recirculated and conditioned within your room only - by design.

Pic for unit in my room: window unit with fan and cooling/heating coil. Image
Indoor air gets recirculated on the side, conditioned and then blown from the top - as shown by my infrared camera. Blue = cold air. orange = "hot" air.
Hint: to know the intake of air on the unit, look where there is dust. Image
Read 12 tweets
Sep 27, 2021
@JudahWorldChamp @kprather88 @CorsIAQ @jljcolorado @HuffmanLabDU @Poppendieck Hotels do not have shared air by design with 1 caveat.
- In your room, you will have a unit that circulates and conditions only your room air (not shared).
- This unit might be under a window, next to a window, or in corridor of your room next to the bathroom.

See pictures below
@JudahWorldChamp @kprather88 @CorsIAQ @jljcolorado @HuffmanLabDU @Poppendieck Typically, for outside air, hotels (like Hilton and Marriott) have an outside air unit on the roof that brings the air into the building.

So far so good.
Your room air is not shared air with other rooms.
@JudahWorldChamp @kprather88 @CorsIAQ @jljcolorado @HuffmanLabDU @Poppendieck There are two ways to get outside air to the room:
1- Supply outside air directly into the room. That is the preferred method. See picture below. You will see a diffuser above the ceiling, next to the bathroom.

If that is the case, your room is isolated from other rooms.
Read 6 tweets
Sep 18, 2021
📢📢New! Air Cleaners Comparison:
1- Selection graph: 1.a. all + 1.b. only HEPA
2- Data download link
3- Request data link
4- Where to place air cleaner?
5- Calculate reqs
6- CADR and noise
7- Letter about unproven tech.

@CleanAirCrewOrg @DavidElfstrom
@kprather88
1a - Selection Graph - All (includes ionizers = unproven tech)
- X axis first cost + first year filter replacement cost in USD
- Y axis: Clean Air Delivery rate = volume of clean air in CFM (cubic feet per min) = ~efficiency x airflow Image
1b - Selection Graph - only includes HEPA
- X axis first cost + first year filter replacement cost in USD
- Y axis: Clean Air Delivery rate = volume of clean air in CFM (cubic feet per min) = ~efficiency x airflow

Fun Fact:
On average, for each 1 cfm of clean air you pay $1.8 Image
Read 12 tweets
Aug 25, 2021
🧵 Answers to what the different strategies will result in term of air change rate

Example used throughout the thread:
👉Classroom: 960 ft2: 30' x 32’
👉Number of occupants: 30 (this is the design number, taking into account average classroom density).
Ventilation by code, this classroom should have 415 CFM airflow of outside air or 14 CFM/person.

👉This airflow is being forced through the HVAC system (unit in classroom or mechanical room).
When we check ventilation, the answer is not “yes” or “no”, the answer should be how much?
Read 9 tweets

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