Thread by @LieslMcconchie

I tested several DIY portable air cleaners to see how they performed in an active classroom environment.

My focus was on PM2.5 measurements.

Here's what I found, and how it's influencing my advocacy for my own kids and beyond ...
🧵

tl;dr
- classrooms produce a TON of PM2.5
- classrooms desperately need better ventilation/filtration
- the original CR box performed the best (of those I tested)

Keep in mind this was a dynamic environment. Lots of variables that couldn't be controlled for. Kids coming and going, doors opening/closing, etc. Kids going to recess/lunch. This was a real classroom behaving normally. Real citizen science stuff.

Methods
Spring 2024
1 classroom (kindergarten) 8,410ft3
22 students
2 teachers
School hours 7:45-12:45
Windows closed
Dylos particle counter
PAC tested:
- One AC Infinity 6-fan PC fan
- Two AC Infinity 6-fan PC fan
- XL Luggable
- CR box (level 1)
- CR box (level 3)
The data⏬

This was the modular 6-fan PC air cleaner first built by @JimRosenthal4 .

https://x.com/JimRosenthal4/status/1715829214396485927?s=20

Since that data wasn't all that impressive, we decided to toss another of the same in the classroom. PC fan style air cleaners are exceptionally quiet so an appealing option for classrooms. Here's the data for 2 of the same, placed on opposite sides of the classroom.
Better.

Next, we tried @cleanairkits XL Luggable.
It's a beautiful machine that is quiet and has a small footprint in a classroom.
And ... it is very efficient at reducing PM2.5

Next was the original CR Box (Lasko fan on level 1).
20x20x2 Merv-13 filters.

And finally the same CR box on level 3.
(This particular classroom runs a CR box on level 3 daily, with no complaints of noise. I know many complain of noise, but this teacher - with a degree in public health - doesn't mind. Maybe it's the room acoustics?)

Conclusion
The original CR box and XL Luggable are both great options for a classroom.
I'd be happy with either in my own kids' classroom.
The XL Luggable is much more expensive, but smaller floor space and quieter.
The CR box is inexpensive, but more floor space and louder.

I like the speed options of the CR box - maybe level 1 during most of the day, but you can crank it up during all the times when teachers aren't doing direct instruction.

The AC Infinity doesn't seem to be a good fit for a classroom. It's great for my office.

Huge thanks to my mentor @JimRosenthal4 for this idea, particle counter, building supplies, and lots of priceless mentoring/conversations. You're a great teacher, Jim!

Again - lots of variables going on here. Take it all with a grain of salt, & a few thousand particles.

And remember, the @CRFoundationUS donates all the supplies you need to make CR boxes to schools, nursing homes, homeless shelters, and more.
Fill out a grant application now - school is starting soon.
corsirosenthalfoundation.org