Corsi-Rosenthal Foundation (US)

LEFT: 2024 Grant recipients
RIGHT: 2025 Grant recipients

Last year was a tremendous year of impact for us at the CR Foundation.
Check out our full report of 2025 activity: corsirosenthalfoundation.org/about/

Details for the curious-minded:
20X30X8 room.
22 people in the room.
3 CR boxes running.
PM2.5 drops from 181 to 3, in 9 minutes.

We don't have any orange smoke, but we do have a particle counter.

Watch these PM2.5 levels plummet in this time-lapse video of running CR boxes for 9 min.

Liam is amazing. So pleased that the @crfoundationus.bsky.social was able to support his efforts.

Great explanation of airborne viruses.

CR Boxes can help remove most of these viruses from the air.

Thank you!
Glad it brought you a moment of peace.

This is the face of a teacher who is learning how easy (and fun) it is to make a Corsi-Rosenthal Box.

Clean classroom air is coming their way!

Join the movement: corsirosenthalfoundation.org/donate/

Donate - Corsi-Rosenthal Foundation Dedicated to providing cleaner safer air for all.

Within the last week we received over a dozen grant applications from schools with poor indoor air quality. We need your help to be able to say YES! Please donate today: corsirosenthalfoundation.org/donate/

Liam delivered all the boxes to the teachers at the STEM school. They were thrilled to have them, and to teach about clean air.

From start to finish, it has been a thrilling project. At the Corsi-Rosenthal Foundation we get to be a part of projects like this all the time. You can too!

Liam reached out to the superintendent. She was thrilled with the idea.

Liam completed a grant application with us. We were thrilled with the idea.

Liam worked with his scout troop to build all the boxes. They were thrilled to contribute.

Liam, a teenager in North Carolina, reached out to us at the Corsi-Rosenthal Foundation in the fall of 2025. To earn his Eagle Scout award, Liam wanted to build 30 CR Boxes for a local STEM elementary school.

What a thrill it has been to watch this project blossom.

Seeley School Community Builds DIY Indoor Air Purifiers SEELEY — In a community where air quality challenges are part of daily life, students, parents and school staff at Seeley Union School District took action this week by learning

Another community building CR boxes for schools!

“There’s not much that we can do about the air quality outside. But being able to create our own safe haven indoors is what we can do to actually have control and autonomy over our own health.”

www.imperialvalleyweekly.com/news/seeley-...

#Cdnpoli #USpoli

DIY #CorsiRosenthalBox air filter units. Infectious disease is airborne and sits in the air like cigarette smoke. Clean your indoor air. #Flu #COVID #RSV

YouTube video by SpiveyCPS UConn Air Quality Initiative

🥹🥹🥹
This 2-min video of students across Connecticut building CR boxes in schools is full of:

Hope
Science
Encouragement
All the feels

Keep advocating for clean air in schools.
We're here to help.
Shout out to Marina Creed & team! 💪🫶
www.youtube.com/watch?v=KkC9...

I posted the 4 filter version of a DIY CR box air filter, and a newer CR box inspired air filter with computer fans, this below is the simplest version of a CR box. It doesn't clean teh air in as large a space as the other two versions but if you need something please try this one fan/one filter.

A DIY air cleaner sits on a table top next to a bottled water. The air cleaner has new white pleated filters and is assembled with blue duct tape.

The @crfoundationus.bsky.social extends its warmest wishes for peace, joy, and healthy indoor air in 2026!

Build a Box Campaign Help Us Bring Clean Air to More Classrooms

🌟None of this would have been possible without your financial support, and your efforts to spread the word that clean indoor air matters.

We have big plans for 2026, and we need your support. Please donate today to help us start 2026 strong: givebutter.com/buildabox2025

box full of IAQ sensors

🌟We closed out 2025 kicking off a major project in the southeastern U.S. involving three schools. We installed over 100 IAQ monitors, and led staff and students to build even more CR boxes. We look forward to seeing the impact CR boxes have on many variables we're tracking.

IAQ advocate Violet Affleck and CR Foundation Executive Director Liesl McConchie.

🌟In September we participated in the Healthy Indoor Air: A Global Call to Action event at the United Nations in NYC. We led a demonstration on how to build a CR box and connected with many fellow IAQ advocates and leaders.

Youth inspired to make their own modified CR box in India.

🌟In August we partnered with Healthy Buildings 2025 in India, providing resources for attendees to build CR boxes. The event sparked interest in young and old alike to take steps to ensure cleaner indoor air.

Kids helping to build CR boxes.

🌟Throughout the year we provided supplies for several hundred more CR boxes to be built for schools, shelters, community centers, heat shelters, and more. Passionate volunteers built them all and put them where they were needed most.

hundreds of CR boxes lined up ready to be transported to LA fire victims.

A few highlights from 2025, and our wish for 2026.

🌟We started off 2025 by providing over 1,100 modified CR boxes to those impacted by the LA fires. It was a massive grassroots effort with many people rolling up their sleeves to help during this crisis.

Nervous about getting together with family for the holidays?
Bring the best present of all, a Corsi-Rosenthal box!
Dress it up with a big red bow of course🎁
youtu.be/1aMOtwcmvpo?...

@crfoundationus.bsky.social

As you can see, I posted about the original CR box here last Christmas. The advantage of the newer type CR box researched and assembled by @davidelfstrom.bsky.social is that they are quieter, which is a plus for classrooms and businesses, and repairable. You can follow @crfoundationus.bsky.social

Excellent - A friend gave me a metal Yeti drink cup inscribed with instructions on how to make a CR Box. 😊

@crfoundationus.bsky.social

The daughter was preparing to participate in her school's science exhibition. She choose to build a mini air cleaner to remove microplastics (based on what she had learned about CR boxes) out of a lunch box.

Inspiring the younger generation to clean the air is meaningful work.

An uplifting story of the far-reaching impacts of Corsi-Rosenthal boxes:
The @crfoundationus.bsky.social sponsored the Healthy Buildings conference in India this year. We provided supplies to build CR boxes. One of the attendees went home & taught their daughter what he had learned ...

People all over the U.S. are coming together to provide clean indoor air for their community.

Look at the wonderful folks of Imperial County, CA leading the way.

Two ways to join the movement:
1⃣Apply for a grant to build
2⃣Donate: givebutter.com/buildabox2025

$4 provides clean air for 1 student for an entire year.
$100 provides clean air for a classroom for a year.

We are 15% of the way to our goal of raising $25,000.

Please help us provide clean air for more children & teachers.

DONATE: givebutter.com/buildabox2025

#GivingTuesday

Our biggest week yet!!

We are thrilled to have the resources to approve 7 new grants this week, totaling 275 CR Boxes.

That is clean air for approx. 10,000 kids & community members.

Please DONATE to help us continue: givebutter.com/buildabox2025