DYI Air Purifier for Wildfire Smoke

air purifier

Facing the worst air quality in recorded history (and my air purifier temporarily inaccessible in storage) I built my own today using Eric’s COVID Air Defense System kit, also known as a Corsi-Rosenthal Cube.  It works for wildfire smoke as well as for Covid.

I followed these instructions to build it: https://encycla.com/Corsi-Rosenthal_Cube

I was able to have the MERV 13 filters delivered the same day by Instacart so I didn’t have to leave my apartment.


  • Comments (8)

    • 4

      That’s incredible! Great effort. Watching from the UK it’s like seeing scenes from Blade Runner 2049. Hope you’re (all) staying safe out there. 

    • 2

      Hardened – just to piggyback on your wildfire smoke “theme”; wanted to relate our past week here in Indiana.   My DW & I drove back from South Dakota for a family event this past Tuesday (6-27).  I failed miserably at situational awareness – driving across Iowa we could see that the smoke cut the horizon to within a few miles ( I’m terrible at judging distances).  Thinking that the car AC would provide adequate filtration was way wrong.  By the end of the day, my throat was burning quite badly & that didn’t dissipate fully for about 36 hours.  Then, just a couple of days later we were hit by the derecho that blew thru the Midwest.   Our power cut out abruptly – along with about 149K other Hoosiers.  Fortunately, it wasn’t too hot that day & our house is well sealed as the air quality was still atrocious.  (AQI of 225 or so).  We were incredibly lucky – our power was only out for three hours  – some folks were in the dark for three DAYS.

      Things to think about!!   #1  Have to more seriously consider a generator.  #2 Glad that I had some MRE’s/hiking food on hand so we could have a hot meal.  I could have used my natural gas grill for cooking as well.  We have a Berkey, so clean water wasn’t an issue.  #3.  Have to put more thought into how to keep cool in a power outage scenario during the summer.  #4.  What are other options for keeping persishables cold?  We have a towable RV, but it is stored several miles away -without traffic lights, that might not be an easy option to retrieve that.

      As several articles have related, we have not seen the last of the smoke, so make sure you have some N-95’s  & up for outdoor wear this summer.  I still have my COVID 3M respirators from my hospital work  – also have some fairly snug fitting googles (the smoke burned my eyes as well).

      I’ve often said that I learn more from failures than successes – the lessons stick with me longer.

      • 3

        Thanks for sharing your experience. And yes, it can be very helpful to hear about what went wrong so we can avoid the same.

        Regarding driving in smoke, most A/C filters are designed to filter larger particles (dust/dirt) that would damage the A/C but are not able to filter out smoke. I would hit the “recirculate” button when driving through anything you don’t want to breathe so that the A/C doesn’t pull in outside air. There are filters that would filter out smoke, such as the MERV-13 that Hardened used, but you’d need to check if those are available for your car’s A/C.

    • 2

      Great that you can remove the larger smoke particulate from the air that you breathe, I hope you can stay safe. Do you have a carbon monoxide detector…or perhaps a canary? Increased levels of harmful gasses with a corresponding decrease in oxygen can have an insidious effect.

      • 1

        Do you think that’s a concern for wildfire smoke coming from another country?  I imagine the harmful gasses are moot at that distance.

      • 2

        Carbon monoxide is lighter than air, so tends to rise fairly quickly outdoors. It’s more a problem for indoor fires because the building traps it. I’m confident that we don’t need to worry about breathing carbon monoxide from wildfires that are more than 100 feet away outdoors.

      • 2

        Since you didn’t mention that the wildfire was in another country in your initial post it was reasonable to think that it was a more immediate problem. If the fire is in another country then surely this is completely pointless.

      • 1

        Yes, good point.  Sorry for the lack of clarity.