The new normal must be extreme airborne mitigation everywhere. Air quality experts need to be front and center. Imagine we had a new measles virus that caused brain damage and vaccines and natural immunity did not prevent infection.

1/3
HVAC mechanical engineers (who are responsible for ventilation) have a basic understanding of air quality, but know very little about airborne virus mitigation. The last virus people assumed was airborne was the measles and that hasn't been a societal threat since the '60s.

2/3
Most are unaware that electronic air cleaning doesn't work. Almost none have ever heard of upper room UVGI. We need indoor air quality standards. Air quality experts need to lead the way. Failing to emphasize that #COVIDisAirborne is preventing that.

3/3
Addendum (twitter needs and edit option). Measles is still a big problem in developing countries. Failing to vaccinate the world hurts everyone.

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More from @joeyfox85

Mar 11
I'm in the @TorontoStar ! Thank you @bcohenn .

#COVIDisAirborne

Also featuring @FurnessColin & @ApricotTreeCaf1

Quotes below. 🧵👇

thestar.com/news/gta/2022/…
- Not enough focus on ventilation and filtration.
- Delay in acknowledging COVID is airborne
- Lack of clear communication
- Ventilation reduces risk of transmission Image
- look for HEPA filters and places with CO2 levels < 800 ppm
- We need operation warp speed for clean indoor air. I credited @j_g_allen for this in the interview.

(I don't believe "people will die from other respiratory viruses" was my quote)

Image
Read 4 tweets
Mar 11
Intro to the Packaged Roof Top Unit (RTU)

I want to do a few tweets about common ventilation issues, but first I need to do an intro to the basic system - the RTU. It's essentially a home furnace with dampers. Here's what they look like:

1/14 ImageImageImage
This is a schematic of what it looks like inside. Here are the steps:

1. Air is returned from the space into the unit.
2. The exhaust damper - air leaves here. It's usually a backdraft damper. Air can only flow out and not in. It isn't motorized.

2/14 Image
3. The mixed air dampers/economizer - these control the ventilation. When they are "open", it means the outdoor air damper is open and the return air damper is closed. This brings in 100% outdoor air. The return damper closing forces the air out through the exhaust damper.

3/14 Image
Read 14 tweets
Mar 10
Time to combat some serious misinformation in this article.

thehill.com/opinion/techno…

1/16
Let's start with the author, Bruce L Davidson @bldmdmph

Apparently, good tooth brushing and mouthwash are underused resources to fight COVID. Is there any real evidence for this?

2/16

How did he get membership to ASHRAE? Between being a doctor, MPH with specialty in pulmonary medicine and associate prof, he got an engineering degree with 12 years HVAC experience? It's not listed anywhere. (I'm an associate member because I only have 11 years experience).

3/16 ImageImage
Read 16 tweets
Mar 6
Here's my number: 87.5%

That's how much of a reduction in COVID spread can be achieved through:

- 6 air changes per hour (ACH) of ventilation +
- Upper room UVGI +
- #CorsiRosenthalBox .

No mandates required.

Where did that number come from?

1/5
75% reduction in transmission of measles from upper room UVGI. 25% remains.

2/5
ncbi.nlm.nih.gov/pmc/articles/P…
50% reduction in transmission of measles from ventilation/filtration. 50% of these remain.

3/5

Read 5 tweets
Mar 3
Why a vaccine only approach is a bad idea:

I'm amazed that this concept exists. It's as if some doctors have pledged eternal loyalty to the vaccine and any additional measures are a form of adultery. It's absurd. Stop encroaching on engineering.

1/9
An engineer's perspective:
a. Especially with boost, vaccines are extremely effective against severe disease.
b. They are not effective long-term in preventing infection.

Because of this, many have said that only severe disease matters. It's not true. Here's why:

2/9
1. We've tried using a vaccine only approach. It's failed in every country that attempted it.
2. What about the immunocompromised, elderly and unvaccinated?
3. A vaccine only approach causes people to blame the pandemic on the unvaccinated. This can't continue.

3/9
Read 10 tweets
Mar 1
Intro to ultraviolet light against COVID 🧵

Ultraviolet light has many different applications. Here are 6 that have been used for COVID:

1. In-duct
2. Stand-alone
3. Upper Room
4. Far UV
5. Surface Sterilization
6. Photocatalytic Oxidation

TL;DR - See tweet 16 👇

1/20
1. In-Duct

A UV light is placed in the duct or by the coil of an air handling unit. It will kill virus particles being supplied to the zone.

I'm not in favor:
a. It can damage the filters
b. Better alternatives are: increasing outdoor air % and improving filtration.

2/20
c. Transmission through ducts is long range transmission. Shared room transmission is much higher risk. Better to focus on higher risk.
d. People in the industry have expressed skepticism to me of how
effective this actually is.
e. UV is more expensive than filtration.

3/20
Read 20 tweets

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