Discover and read the best of Twitter Threads about #CorsiRosenthalBox

Most recents (24)

When to change the filter on DIY #CorsiRosenthalBox? Holder et al (…) showed that performance degradation depends on contaminant: Dust reduces airflow. Smoke kills electrostatic properties. @JimRosenthal4 @joeyfox85 @CorsIAQ Table for MERV 13 single-fi...
@JimRosenthal4 @joeyfox85 @CorsIAQ Note the test substance for the CADR PM2.5 performance measurement was simulated wildfire smoke.
The same would likely apply to a commercial HEPA air cleaner. Monitor for clearing time for a fixed release of contaminant with a simple PM meter.
Read 6 tweets
All of that smoke you see your neighbors breathing in, but not you because of your #CorsiRosenthalBox and N95s?

Is made up tiny particles called Airborne Fine Particles - or AFPs.

And AFPs work SYNERGISTICALLY with viruses to worsen infections.

A synergistic 🧵. Image
H/T @sri_srikrishna for the study.…

Right off the bat, we already know that pollution makes Covid worse.

First pic:…

Second pic:…

But why? ImageImage
So, they came up with AFPs, like:

✅ ⚠️ Biochar particles like from wildfires. ⚠️

✅ From the atmospheric environment - PM 2.5.
✅Dust particles with silicon.
✅ Carbon black particles like what you breathe in every day on your drive home. Image
Read 9 tweets
1/n Because public health is so incompetent here are my thoughts if you're at home surrounded by wildfire smoke.

A. If you have the wherewithal - prepare your home for vacation & leave until its safe to come back. Arrange to meet your home owners insurance requirements.
B. If you can't leave, prevent outdoor air from entering your home; close windows, doors, and shut down any mechanical systems connected to the outdoors.
C. If there is an outdoor air duct connected to your air systems (furnace, a/c, HRV/ERV, central vac etc) block them...take pictures to remind yourself what you have you can undo when its safe.
Read 13 tweets
Making the case for the #CorsiRosenthalBox with studies.

A simple thread.
"no U.S. Energy Star certified air cleaners have CADR values (for either tobacco smoke, dust, or pollen) matching the CADR value for the CR Box even on low speed "

On cost? 1/10th.

1019 to 1444 m3/hr CADR.

(600 to 850 ft3/min)

Published here:… ImageImage
An incredibly thorough study published in February 2023, with all of its authors from @NIOSH.

With universal masking in a 3-ply cotton mask, exposure to the relevant aerosol size is reduced by 88 to 94%, with the #CorsiRosenthalBox.

73% w/ CRBox alone.… ImageImage
Read 21 tweets
The Chief Scientist of the World Health Organization, folks, speaking to a very important subtext.

The historically IAQ inequity that exists world-wide based on racism.

In America? The completely inadequate HVAC of urban schools.

Driving on I5 through ANY major city?
Look out your window. You have time as you are stuck in traffic.

Think about two things.

1. Why haven't you improved your air quality in your car by:

✅ Building a mini #corsirosenthalbox.
✅ Replacing your cabin air filter with HEPA grade.
✅ Or wearing an N100.
Two hours a day sucking in UltraFine Particles (UFPs). Like cancer? Systematic inflammation? Endothelial Dysfunction (same initials as Erectile Dysfunction)? Asthma? COLD?…. ImageImage
Read 7 tweets
With the horrible air quality from #ABWildfire I’ve put some MERV13 rated furnace filters in my windows so we can get clean, cool air in the house. It filters pollution out of the air as it blows into the house. Filtrete1900’s are MERV13. #yeg #yyc Screen door with a furnace ...Slider window with a furnac...
To fill the large gap on top I cut a piece of cardboard and duct taped it to the filter. Used some peel & stick weather stripping along the edges of the filter & cardboard. So it’s easy to take in and out.
I’ve also got #corsirosenthalbox and HEPA filters running inside the house. I’ve made a variety of types over the years using different fans & filters. Lots of size and noise options.
Read 7 tweets
1/ New CDC recommendation on ventilation - as equivalent ACH (eACH). Aim for at least 5 air changes each hour and upgrade to MERV-13 filters. More thoughts below.…
2/ It's a good start and should decrease inhalation dose of respiratory aerosol concentrations by between about 20% to 40% in many classrooms (based on my experience w/ typical starting points in schools --some w/ recirculation through MERV-13 filters already achieve 5 eACH).
3/ Importantly, it is NOT difficult to achieve MUCH higher than 5 ACH in classrooms - even approaching 10 equivalent ACH w/ ASHRAE 62.1 ventilation + a #CorsiRosenthalBox, or 6 ACH w/ 62.1 in a typical classroom & a good HEPA air cleaner.
Read 6 tweets
Schools please open the windows 🪟
1 in 10 COVID infections lead to long covid.
Please protect children and staff
Build a #CorsiRosenthalBox
Around 40% of infections are asymptomatic
Mild infections still cause long term risks.
#Covidisairborne Ventilation and Airfilters are key to reducing infections. Here is a recent video of Dr Fauci explaining that airborne transmission predominates
Read 14 tweets
Great interview!

@JeremyFarrar is an ally, and is the Chief Scientist for the WHO.

Please do not use this thread to attack him or the WHO.

When they speak the truth? Reward the truth. Often, honey is far more effective than vinegar.

Quick 🧵.
That's right. He said it. Enjoy that moment. Here, share my enjoyment of hearing those words again..... Image
Read 7 tweets
Efficiency vs. Effectiveness - They are Not the Same

Over the past 3+ years there has been a sharp rise in interest related to indoor air cleaners. I have consistently seen confusion over the terms efficiency and effectiveness. This thread is about the difference. 1/
When thinking about air cleaners, make sure not to conflate efficiency and effectiveness.
An air cleaner that is intended to remove aerosol particles from indoor air can be close to 100% efficient at removing particles as they flow through the device. 2/
That sounds great, right? Maybe. Maybe not. In fact, a device that is 100% efficient (captures all particles that move though it) may be highly ineffective. What? How can this be? 3/
Read 21 tweets
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. 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. 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

Read 11 tweets
Weekend 😊 😊
… now with some extra urgency since a little lady has a fever A PC fan #corsirosenthalbox in progress. Right side of image
I might as well tweet the process.
Just took a break to feed everyone.

So far I have gathered all my materials, tested all of my fans to make sure they work before I install them in this contraption!
Power (and lights because I’m using RGB fans in this one) all work 😊

My 20x30 filters still haven’t arrived. I have 20x20 filters left so I’m making one that size.

I have 20x30 foam board, which was the perfect size to make the non-filter sides of the device.
Read 56 tweets
1/ Challenged by some as to why I am wearing a mask in this video if the CR Box works so well. First, I wear an N95 mask in all indoor shared spaces at work. I do not apologize to anyone for that.
2/ For the size of the dean's suite & level of ventilation, this single CR box reduces our inhalation dose of respiratory and other aerosol particles by roughly 50% on high setting. That's good, but not nearly the dose reduction achieved by wearing a well-fit N95 mask.
3/ An N95 mask yields at least a 1 in 20 (95%) reduction in inhalation dose of virus-laden respiratory aerosol particles (and higher for particles of the size most relevant to conveyance of SARS-CoV-2).
Read 5 tweets
I just realized not everyone knows this lifehack, so here goes:

Never trust case rates or CDC maps. Especially if (like me) one person with a cold can take you out for months! It’s too much to keep track of & it’s increasingly unreliable.

Instead, trust in the laws of physics.
I don’t need local crash statistics to buckle up, and I don’t need local case rates to mask up. Granted I’m in Florida so just leaving the house is an adventure in both areas most days lol. But I don’t mind doing one easy, highly protective thing every time I go out.
I’m a big fan @lazykendra and her advice to “Decide Once.” And when you Decide Once to always mask indoors 100% of the time, life actually gets WAY easier! No more case rate vs. crowd calculus. No more RSVP stress. Just find some quiet outdoor patio spots and relax.
Read 6 tweets
Snow day was perfect for putting the finishing touches on the fandelier 😊
@CRBoxKits @robwiss

MERV-13 24x24x2 top
MERV-13 16x16x1 bottom
12 arctic p12s except I can’t count and 9 are white and 3 are black

LED tape from Lee Valley h/t @Mark_Ungrin Image shows the underside of a suspended fandelier. A square
PC fans are about $10 each. The electrical components make this more expensive than the box fan style #CorsiRosenthalBox. With shipping I figure this cost $250 to build. I have been slowly obtaining the parts over 3 months.
Earlier this month I took the box fan CR box fan from my kitchen to a local community centre. I needed to replace my kitchen filtration. I’m glad to get this done.

Here’s a list of parts and resources for building your own PC fan version!…
Read 6 tweets
Many people ask me how to work with schools to implement #CorsiRosenthalBox es. I want to share a story about one small school in a rural community in Arizona that is doing it right. 1/
Our team was contacted by Red Rock Elementary in Red Rock, Arizona because they had concerns about their air quality and wanted to do something to reduce the number of kids who are missing school for illnesses. 2/
They wanted to learn more about the impact of IAQ on health and whether #CorsiRosenthalBox es might be a helpful addition to their school. They decided that they wanted to build a #CorsiRosenthalBox for every classroom. 3/
Read 12 tweets
1/ Me! Here! Please call on me! Over here! Please!

Answer: Significantly reduce inhalation dose of virus-laden respiratory aerosol particles.

How? The 3Rs.
Remove the source.
Reduce the source.
Remediate indoor air.…
2/ Remove source = Test & isolate, stay home if feeling any symptoms, etc. Y'all should know the score by now, right?

Reduce source = Communal protection by everyone wearing a mask to reduce emissions from those infected. Sadly, communal protection seems forever off the table.
3/ Remediate indoor air = wear a high-quality mask (e.g., N95 to remediate the air you inhale), increase ventilation, improve filtration, add filtration (including standalone HEPA air cleaners and/or #CorsiRosenthalBox es), employ UVGI.
Read 4 tweets
Went to Burnaby Hospital with small #corsirosenthalbox No questions asked. The DIY cover/carry bag with handles hid filter pleats. Likely why no stares at it. RockSolar power bank kept it running as I carried 13x13x20 unit. Also had portable rechargeable slung over shoulder neck.
I found the RockSolar power station used. Delivery from Amazon is not quick. Whole set up was light/easy to carry. CO2 was excellent in hospital, but was happy to have the air filtration. Small #corsirosenthal is 13x13x20. Forgot to put shroud on this one. Oops.
Made the cover/carry ‘bag’ for small CR with washable polypropylene on bottom & for straps. Stretchy mesh fabric on the sides lets air thru. Have purchased 3 types mesh. This mesh from Etsy is best: 2way stretch/doesn’t run. Delivery faster than expected…
Read 10 tweets
1/ Today I popped along to The Shed in #Crewkerne. Allow me to introduce you to two wonderful people, Mick and Mike, who have built something quite special…
#CorsiRosenthalBox #CleanAir A picture of a street in Cr...
2/ Meet Mick and Mike!👇 Last year they built a wooden #CorsiRosenthalBox in collaboration with @SmartairUk. However they used a metal cage fan & some small HEPA filters, but they built the frame to accommodate @3MUK MERV13 filters. Smart Air asked if I could bring some along… A picture of Mick and Mike ...
3/ Check it out! What a great bit of kit. This is now my very last #CorsiRosenthalBox I’m giving away for FREE - and it’s a special one! My DMs are open 😊 #CleanAir #Somerset 🇬🇧 This is a series of picture...ImageImageImage
Read 4 tweets
I had so much fun this morning building a PC fan based #CorsiRosenthalBox.

Maybe part of the problem here is that people don’t like being told what to do and it’s actually fun to solve problems yourself.

Problem: we have a new airborne virus that can kill and disable people. /1
You become infected when you inhale infectious aerosols that hang in the air like smoke. The infectious aerosols got there from someone else breathing them out. That person may have left the room hours ago, or they may be present, continuously exhaling infectious aerosols. /2
How do you stop transmissions? How do you keep yourself, your friends and family, your fellow human safe?

Read 7 tweets
@CrabbBrendan great to meet, thank you! These are the upgraded #corsirosenthalbox we’ve built for preschool #COVIDIsAirborne Image
Here are the drawings for anyone interested to build their own. I will put the links below too and I should thank @ColinKinner for sourcing the fans, adapters, etc!! We just copied him!
#corsirosenthalbox ImageImageImageImage
IKEA starkvind filters…
P14 Arctic fans from mwave…
Finger guards a wood below
Electrics to follow in next tweet
Read 6 tweets
1/ The guiding principles of the original #CorsiRosenthalBox design were (1) cost-accessibility (reduce disparities in ability to breathe cleaner air) & (2) effectiveness (in range or better of more expensive commercial HEPA air cleaners). (photo courtesy of @JimRosenthal4)
2/ The original concept exceeds expectations in each area and has now been proven highly effective by many researchers w/ additive equivalent ACH that easily get many classrooms above 9-10 equivalent ACH (CR Box + ventilation) at relatively low cost.
3/ The recent NIOSH/CDC study indicates that two #CorsiRosenthalBox es in a classroom can add greater than 12 ACH to ventilation ACH - likely exceeding 15 equivalent ACH total. As some context, this exceeds ventilation design for most hospital isolation rooms. Yep. Knew that.
Read 7 tweets
1/n Eventually, people will get alarmed by this, or claim it's exaggerated. So here's a short explainer. Yes, repeated covid infection tends to badly age parts of your immune system, causing a deficiency compared to normality. That's the first part.

2/ No, obviously (as yet) the immune deficiency caused by repeated covid is not on the same level as what HIV/AIDS causes. It is, however, quite bad for you, & fits in very well with the observation that covid worsens your average risks of death by 10 years.
3/ We've known quite a long while that covid is pretty damn bad on your immune system for many people. None of this is new, none of it a surprise. Read this thread in full.

Read 5 tweets
🧵Do-it-yourself (DIY) air cleaners: Evidence on effectiveness and considerations for safe operation

Angela Eykelbosh, Environmental Health and Knowledge Translation Scientist, @ncceh National Collaborating Centre for Environmental Health
Jan 18/23

LINK:… Key Messages - A review of ...
Do-it-yourself (DIY) air cleaners: Evidence on effectiveness and considerations for safe operation

Angela Eykelbosh, Environmental Health and Knowledge Translation Scientist, @ncceh National Collaborating Centre for Environmental Health
Jan 18/23

PDF:… Key Messages  - A review of...
Read 24 tweets

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