Particle Capture Tests For the particle capture tests, CK used a Met One GT-531 particle counter. This particle counter is best for HEPA outlet tests because it measures down to 0.3 micron particles—the hardest particles to capture. CK noted 0.3 micron and 2.5 micron particle counts with and without the HEPA. Importantly, this particle counter […]
I wrote early on that my number one concern in China is particulate pollution. It’s on so many people’s minds that nowadays even the guy I buy chuan’r from knows the word “PM 2.5.” HEPAs do an amazing job at removing particulates, but particulates aren’t everything. Gases like volatile organic compounds (VOCs) are so small that they slip through HEPAs. “VOC” […]
How long do Smart Air HEPAs last? My quest to give a solid empirical answer has now completed 130 days! Gus is still dutifully tracking the effectiveness of the HEPA he’s been using in his bedroom since January (with a trip to the US in the middle), calculating the percent reduction in particulates every night. […]
joshuaw81 提问: Hi Thomas, just started one of your cannon kits earlier today and it’s already turning gray. Already a fan of your work! Two quick questions for you: 1- I received a foam/fiber square that is white on one side and light green on the other. I’m assuming this is packaging, and not part […]
My collaborator Gus Tate suggested we work with our HEPA manufacturer to get smaller, square HEPAs. Now we’re convinced the DIY filter just got a lot cuter: Cute and kicks PM 2.5 in the pants.
Adam in Suzhou sent me a picture of a creative solution to a filter problem. The fan he had at his house had an opening that was slightly larger than the HEPA. So Adam cut out a piece of cardboard to close up the edges. Great idea! Adam says, “It’s already turned slightly gray after […]
passport4adragon 提问: Hi, I’m in Shanghai and recently put together your DIY purifier and bought the same fan and filter you suggested – I think it’s working! A couple of questions – 1. I bought the exact same filter you did on Taobao – how often should it be replaced if I run the purifier […]
Based on my research into how different filters work, I concluded that a HEPA filter is all you really need to fight particulate air pollution in China. Given the fact fancy air purifiers run for 8,000 RMB here in Beijing, and I’m only here for a year, I thought I’d try making my own DIY […]