When I made my first DIY purifier, I put the filter on the front: That led me on a long, unexpected journey. It turned out that I wasn’t the only one interested in breathing clean air in China, so I started a small social enterprise called Smart Air to ship these low-cost purifiers to fellow-air […]
Category: Filters
Protect yourself from cities with bad air pollution: A Beginner’s Guide
So you’ve found yourself a city with bad air polluted – perhaps you’re in Beijing, Bangalore or Bangkok? Or try Delhi, Ulaanbaatar or Shanghai? What can you do to keep air pollution from trimming years off your life? When I moved to China in 2007, I wasn’t a dummy. I was a college grad, and […]
Do we need add-on air purifiers？
Soon after I started making DIYs, people emailed me asking if we could make a DIY for their car. My initial reaction was, “Great idea!” On the highways, we’re surrounded by all of that awful pollution. Best to purify that air. But as a methodical nerd, I wanted to do some tests first. The results of […]
Tesla’s “Bioweapon Defense Mode” Is As Effective As…A 2010 Mazda?
Tesla rolled out its “bioweapon defense mode” to lots of fanfare and media attention. Tesla went big: “Bioweapon Defense Mode is not a marketing statement, it is real. You can literally survive a military grade bio attack by sitting in your car.” Elon’s telling the truth, but not the whole truth. Tests I’ve done […]
Can I Clean or Wash HEPA filters? – Supplemental Data
This post contains supplemental data for the post “Can I Clean or Wash HEPA filters?“. It includes detailed information about the testing method, and the original data, open-sourced for all to view. Click here to view the original article Open Data Particle Capture Tests For the particle capture tests, CK used a Met One GT-531 […]
Can I Clean or Wash HEPA filters?
HEPA filters are a nearly perfect solution for air pollution. They are backed by tons of scientific tests; they’re pretty cheap; they use about as much energy as a lightbulb; they even have documented health benefits. Just about the only remaining problem is that you have to throw out the HEPA filters every few months. So wouldn’t it […]
Can Activated Carbon Remove Formaldehyde?
Can activated carbon remove formaldehyde? In a previous blog post, I wrote about how my tests showing that carbon can reduce VOCs from cigarette smoke. I also wrote about who actually needs activated carbon to reduce VOCs (hint: not everyone). But here I test whether carbon can filter out formaldehyde. Formaldehyde is a big […]
Is a 30 RMB HEPA Reliable?
After I published directions for how to make your own purifier, people asked me: “Which HEPAs should I use? Is this one trustworthy?” That’s the type of question that makes a nerd like me happy because it means we need to get more data. So I ordered HEPAs from every manufacturer I could find, and I […]
Does adding a carbon layer reduce particulate effectiveness?
I recently published tests showing that carbon actually removes VOCs. But adding that carbon layer raises a question: adding carbon means the fan has to power through yet another layer of resistance. Does that make purifier less effective at removing particulates? Methods To test this question, I ran 10 room tests with the Cannon and 10 […]
Does Carbon Really Work?
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” […]