🧵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)

https://twitter.com/marwa_zaatari/status/1575639767517364225

Examples of what the employee told me:

1) The results were fabricated for financial gain.

(2/7)

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

https://twitter.com/marwa_zaatari/status/1448477729347850241

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.

🧵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.

@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.

📢📢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

🧵 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).

📢📢📢 Updated Air Cleaner Chart:

I added the DIY CR box as optimized by @DavidElfstrom.

Look at this beauty!! @kprather88 @JimRosenthal4
It is the most cost effective purifier on the chart.

See below 🧵 comparison to intellipure(tm) /Blueair (tm)/needle point bp ionization

https://twitter.com/DavidElfstrom/status/1429526273009889286

How it compares to Intellipure?
DIY CR/DE Box is 9 times cheaper and 2 times more effective and less noisy than Intellipure! @Mssarahmssarah

🧵 Is it enough?

"We did ventilation school assessment, we bought 2 air purifiers for each room for $40 million" "we conclude, it is safe to return."

A lot of time and money was spent. The school ventilation assessment is a great starting point, but what was the outcome?

https://twitter.com/BarbarossaDude/status/1428397288339218437

Ventilation assessment reports can be found here: survey.nycsca.org/files/

I looked at many classrooms. Similar findings. Most do not have outside air and problems with exhaust fans of bathrooms (unless I am missing something - no reports it was fixed?).

🧵Following-up: I did incognito testing at a famous casino last Aug. On my there, I felt uneasy - casinos were open and schools were closed.

However, this experience opened my eyes: if casinos can open safely and do it right, so can schools..

@HuffmanLabDU @DrEricDing

https://twitter.com/marwa_zaatari/status/1427070887950524421

COVID Safety Plan (1/2)
- People density was at 50% (by design)
- Other measures below.

Updated 🧵Which air cleaner do I buy?

Type, efficiency, purchase price, replacement cost + filter life, and noise.

New results/charts about Intellipure DFS(TM), Blue Air(TM), and needle point bipolar ionization.

@DavidElfstrom @HuffmanLabDU @Parents4IAQ @RobynSchofield3 There are three types of air cleaners:
- Subtractive: like filters, will remove the contaminant when it comes in contact with the media
- Additive: like ionizers, will emit ozone/radicals/ROS/etc.. to react with the air (will emit something to remove something)
- Hybrid

🚨 UNSAFE AT ANY LEVEL.

This is not an issue for debate: Ozone generators used as air cleaners are PROHIBITED (no maybe, if or but).

🧵 I packed the links and snapshots from ASHRAE/EPA/@CorsIAQ/@CJWeschler.

Please help if you know of a school that installed such devices.

https://twitter.com/KHNews/status/1393191620351234049

ASHRAE Standard 62.1:
1- Prohibits the use of ozone generators (pic 1)
2- Requires compliance to UL 2998 (zero ozone) (pic 2/3)

HVAC without V is a HAC(k) job

🧵 about ventilation
- Mechanical versus Natural ventilation
- ASHRAE Standard 62.1 historical rates
- Why schools are under-ventilated?
- What is the cost of outside air?
- What we should do about it? Note 1: According to ASHRAE Standard 62.1 (most prominent ventilation standard), ventilation is not only about outside air. Rather, it is the sum of outside air and return air that is cleaned.

In this thread, I will focus only on outside air.

🧵about "Blueair" purifiers:

Consumer report rated this purifier as one of the best purifiers consumerreports.org/air-purifiers/…

1) Misleading marketing:
The filter used is called "HEPASilent". It is not a HEPA filter.
It is a common pleated filter + ionizer. 2) By-products:
The company claim to produce low ozone.
It is certified by CARB to produce < 50 ppb.
They have a carbon filter which will capture some ozone - although % will decrease with use (we don't know how much % versus age).

Indoor ozone levels should be < 5 ppb

🧵I am going to expand on the first point from @don_milton. See @linseymarr tweet below.

-How to achieve 10 L/s/Person (22 CFM/person) of outside air
-What does it mean in terms of 3’ to 6’ social distance.
-How to achieve >4 ACH
-Myths regarding air cleaning

https://twitter.com/linseymarr/status/1373362901684211723

Example used throughout the thread:

Classroom: 960 ft2
Specific dimension: 30' x 32'
Number of occupants: 30 (this is the design number, taking into account average classroom density - pre COVID)

Check here for a Step-by-Step guidance how to choose an ionizer or a UV+catalyst device. Follow these simple 3 steps for proper selection! Step 1: STOP 🛑 do not do it. Do not think about it. At best It does not work, at worst it produces harmful by-products.

I will show an equal love to another bi-polar ionization technology claiming the usual 99.99% and no by-products.

In this thread, I will discuss two studies one by FEMA/CDC and one by Bureau of Toxic Substance Assessment (BTSA) NY versus the manufacturer claims.

https://twitter.com/4everPelvicPain/status/1365658538232582147

Manufacturer claims no (ZERO) ozone production. Published test on the website from an outside lab:
atmosair.com/wp-content/upl…

Test Date = 2005

More results involving Electronic Air Cleaners. This time using Hydrogen Peroxide in the air for air/surface disinfection (PCO + DHP).

I will focus on the air disinfection results.

Results are from a chamber test 👇. Principle of work per manuf.: the device produces dry hydrogen peroxide with max concentration of 20 ppb that is able to last long enough to diffuse throughout the space (half life is 30 - 60 mins; for comparison: half life of ions is in the seconds).

trane.com/content/dam/Tr…

The defeat of ions.

Thread about Needle Point Bi-polar Ionization.

What the manufacturer claims versus what independent studies report.
@ShellyMBoulder @jljcolorado @JimRosenthal4 What the manufacturer claims?
I will focus on three claims: reduction of PM count by agglomeration, surface inactivation of COV-2, removal of VOCs + formaldehyde.
-GPS+MERV 8 reduced particle count concentration by 89.7%
-GPS report 99.8% SARS-COV-2 surface inactivation

1) About MERV 13 - upgrading filters to MERV13 is the cheapest and most consistent/ practical solution:
For a 10,000 ft2 school buildings or 15 classrooms, it only costs $546/YEAR. This simple upgrade will give you ~5 ACH.

https://twitter.com/j_g_allen/status/1361279469588271110

2) About air purifiers, it costs equal or more than $250 to put 1 purifier in 1 classroom (500 ft2) to give ~5 ACH.

Here is a collection of air purifiers available on the market (fan + HEPA filter) compared by cost/ft2 and noise.

If my school building was running the way it was supposed to be run (compliant to minimum codes), how would it rate per Harvard-CU Boulder Air Exchange Rate Target?

In other words, are we asking too much from school buildings? 🧵

@j_g_allen Classroom
- 500 ft2, 12 kids
- served by a central AC system

To obtain the certificate of occupancy (to be allowed to occupy the classroom), this classroom need to have minimum outside air according to building codes. This is by design and should be kept in operation.

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?