High Dynamic Range DIY Air Testing

DIY testing of air cleaning is practical, and thoughtful experimental design can substitute for high-quality sensors including for evaluating air purifier setups that give >100,000x particle reductions. I've done a lot of DIY testing over the years ( 1, 2, 3, 4, 5, 6). The goal is generally to understand how well something removes particles from the air. A professional particle counter (example) costs thousands of dollars, and they're amazing devices, but what you're paying for is convenience, reliability, calibration, and dynamic range. If we're willing to give up on convenience and buy multiple devices for reliability, we can cheaply address calibration and dynamic range with experimental design. The cheapest ready-to-go option for DIY work today is probably the Temtop P600 which I see as $70. While I haven't tried it, it's a stripped-down version of the Temptop M2000 which I bought several years ago to use for my DIY experiments. If you want to make something cheaper, you can get a…