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Mar 19 • 11 tweets • 5 min read
How much does clean air cost?

I was asked by @jm_mcgrath at 22:12 how much our recommendations would cost businesses. Want costed options for your business to provide 6 air changes per hour? Here are 9 options. 🧵

1/11

twitter.com/i/broadcasts/1…
1. The Box Fan #corsirosenthalbox . The original design and the cheapest way to clean the air. 500 CFM. Use 1 every 500 sq ft. Cost is around $100.

Total: $0.2-$0.3/sq ft.

2/11
itsairborne.com/box-fan-cr-box…
2. PC Fan CR Box. Tower of Power. The advantage is that it takes up less space and it's quieter. Those advantages come with a cost. 480 CFM. $390 (CAD). Or DIY - approx. $250. Use 1 per 500 sq ft.

Purchased: $0.8-$0.9/sq ft.
DIY: $0.5-$0.6/ sq ft

3/11
cleanairkits.com/product-page/t…
3. Taotronics

These can be run on low. 89 CFM, $90 CAD. One for every 100 sq ft. Noise permitting, you can increase the speed. You’ll need to buy a bunch of them.

Total:0.9-$1.00/ sq ft.

4/11

4. Smart Air Blast Mini

If you want a powerful and quiet commercial filter, this is probably the best. $550. 435 CFM. 1 For every 435 sq ft.

Total: $1.2/ sq ft.

5/11
smartairfilters.com/en/product/bla…
My favourite resource for purchasing HEPA filters is @CleanAirStars

6/11
cleanairstars.com
5. Upper room UV

You can get 30 ACH with this. Depending on the space and installation, likely to cost around $2-4 k for 1000 sq ft.

Total: $2-4/sq ft.

7/11
itsairborne.com/intro-to-upper…
6. Far UV

Educate yourself before going down this path. Using the Trillium would be $3000 for every 500 sq ft. & 30-60 ACH. I think Sterilray is around $4k (CAD) and can be used every 1000 sq ft (not positive).

Total: $4-$6/sq ft.

8/11
itsairborne.com/intro-to-far-u…
7. Upgrade to MERV-13 filters

This might not get you to 6 ACH, but could add in around 2 ACH in addition to existing ventilation. For 2000 sq ft, I'd estimate an extra $250-300/year.

$0.1-0.2/sq ft./year

9/11
8. Doubling ventilation

I referenced this study. $40/person/year. Payback is 6.5-7.5k per year. $160 back for every $1 spent. Like I said, “orders of magnitude”. Would likely add 2-3 ACH and get you up to 4-5 ACH.

10/11

9. Long term ventilation upgrade

$17/person/year. Up to 8 ACH. This will incur a high capital cost, but be more than worth it over the long run.

11/11

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More from @joeyfox85

Joey Fox Profile picture
Mar 21
These hospital outbreaks need to stop. Vulnerable people deserve protection. We've laid out clear plans on how to prevent these healthcare acquired infections. 🧵

1/6
cbc.ca/news/canada/ki…
Hospitals should already have 6 ACH in occupied areas, but that doesn't even apply here because of our upper room UV recommendation (see below).

They should comply with CSA standards, confirmed with CO2 monitoring. The CO2 levels can be found here: ospe-calc.herokuapp.com/Healthcare_-_B…

2/6 Image
Our filtration recommendation doesn't apply either because CSA standards already require high rated filters.

Upper room UV is a must for hospitals. Easily provide 20-30 ACH. You can easily make the whole building like an airborne infection isolation room.

3/6 Image
Read 6 tweets
Joey Fox Profile picture
Mar 14
These documents are completely inadequate. It's what happens when the Chief Medical Officer of Health refuses to admit that it's airborne.

The ventilation comments are completely insufficient.
1/5
Here's the ventilation guidance.
- No targets
- No requirements
- Misinformation about short range transmission

It's just saying "do what you can". BTW, when is ventilation "inadequate"? They don't say.

If you want to know what a real plan looks like...

2/5
1. 6 air changes per hour in shared spaces using ventilation, filtration or UVGI.
2. Comply with minimum ventilation requirements as set out by ASHRAE and CSA.
3. Monitor CO2 to confirm compliance. You can find what the CO2 levels should be here: ospe-calc.herokuapp.com

3/5
Read 5 tweets
Joey Fox Profile picture
Mar 7
Hosting a Wedding or Large Party.
How to ensure clean air and make it #DavosSafe 🧵

The full layered approach is vaccines, rapid tests, masks and clean air. I'm focusing here on clean air. The other steps can also be used.

1/7
Do as much outside as possible.

The bigger the venue, the better. More space and higher ceilings means better dilution and lower risk.

Your three tools are ventilation, filtration and UV. We'll go through them one by one.

2/7
Ventilation:
Find out what you can about the ventilation. Ask if they can increase it during the gathering and ensure it is scheduled properly and not in auto. If there are windows or doors, try to open them. If there are ceiling fans, turn them on.

3/7
Read 7 tweets
Joey Fox Profile picture
Feb 28
How I deal with the dentist 🧵

It's one place where you have to remain indoors for an extended period of time without a mask. There are ways to reduce risk. It's important to be able to assess risk as well. Here is what I look for.

1/12
Before I go, I ask the following questions:
- do you have HEPA filters in every room?
- do you have barriers between rooms?
Those are the two things I need before I go.
I also ask if they know anything about the ventilation and they usually answer they don't.

2/12
When I go, I bring my CO2 monitor and check to see if I can hear the ventilation or check the thermostats to see if they are "on" and not "auto". If they are in auto, I let them know. If the CO2 > 800 ppm, I won't go back.

3/12
Read 12 tweets
Joey Fox Profile picture
Feb 23
I guess this needs repeating again.

Particulate matter is a concern in indoor spaces and the use of HEPA filters or Corsi-Rosenthal boxes can have massive health benefits.

🧵 Image
Fine particulate matter, also known as PM2.5, is a serious health hazard. There is clear guidance from the WHO - it should be as low as possible.

What tool reduces particulate matter? Filtration - using either MERV-11 filters or higher or HEPA filters.

who.int/news-room/fact… Image
From a health perspective, you cannot over ventilate or over filter the air.

Talking about over-filtration is the same as saying that you should be breathing in more dust. It's ridiculous.

Image
Read 6 tweets
Joey Fox Profile picture
Feb 20
Want a breakdown on the different options for portable air cleaners?

"Box Fan CR Box, PC Fan CR Box or HEPA Filter. Which one is right for you?"
itsairborne.com/box-fan-cr-box…
The box fan CR box is the cheapest way of cleaning air and can be scaled up. It's the best option in large spaces. The most important aspect is equity: it makes clean air available to everyone. The sound is > 47 dB. It's tolerable in many places, but not all. Image
IMO, we need a better box fan with a built-in shroud and quieter noise at 43 dB or so.

The PC fan CR box is ultra-quiet and the best long term solution. It's more difficult to DIY and if you purchase one, it isn't cheap. Currently, it is best for residential settings. Image
Read 4 tweets

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