I built a makeshift air purifier with an HVAC filter & fan. It’s making a big difference, reducing smoke smell & irritation. I’m measuring 50% reduction in particulates after 30 mins, reducing indoor AQI from “very unhealthy” classification to “unhealthy for sensitive groups”.
Running ~1hr on/off cycles to compare air quality with/without. Just started 2nd on cycle. I’ll post legit plots later & a writeup on @hackaday.io, but for now, here’s a screenshot of my live preview, showing 2.5um particle counts in ug/m3, with ~50% dip during first on-period.
Didn’t know someone else had already approached this quantitatively, with amazing results:
Here’s a simpler design.. a 20x20” filter taped directly to a 20” box fan. Use what you got. For better efficiency you want to seal the filter against the outflow side of the fan.
https://t.co/MN9iyRY4hO
Stalled just a hair short of 50% reduction this cycle.
I’m using a MERV-11 rated filter which, turns out, only promises 65% reduction for particles smaller than 3 um. Should get 90% or better with a MERV-15+ filter. Off to the hardware store..
epa.gov/indoor-air-qua…
My wife just brought up the issue of storability after the smoke clears. To which I say 🤷♂️
Outdoor AQI spiked absurdly high this morning, corresponding to the #BobcatFire 4am flare-up in Monrovia Canyon. My filtration experiment was helped by generally improving AQI outside, but there is a clear correlation with filtration on vs off. Need a better filter (MERV-15+)..
Share this Scrolly Tale with your friends.
A Scrolly Tale is a new way to read Twitter threads with a more visually immersive experience.
Discover more beautiful Scrolly Tales like this.