Answering this question is more difficult because you need a controlled environment (for example, you don’t want to walk in and out of the room during the test), and you need to test the air for a longer period of time. But fortunately for you, Thomas is a huge nerd and does this kind of thing for fun.

To answer this, Thomas set up the particle counter on one side of his 13.5 m2 bedroom and put the DIY filter on the opposite side of the room. Here’s what our filter did in one hour: