Should air purifiers have the filter on the front or the back–is it better to push or pull air? The Smart Air lab in Beijing ran tests of the same fan with the HEPA filter on either side, and the results contradict most people’s intuition. When I made my first DIY purifier, I put the […]
Category: Indoor Air
Recent Indoor Air Articles:
Is the Molekule Air Purifier Worth It? Review
Over this last Christmas, I was at home on the couch, and my dad asked me if I’ve seen this new Molekule air purifier he saw an ad review for. He asked because I’ve been building and testing DIY air purifiers ever since a Beijing airpocalypse in 2013 had me coughing for weeks. […]
How Long Does It Take for Formaldehyde &Amp; VOCs to Off-Gas From Your Home?
An important question about formaldehyde is how long it takes for formaldehyde to off-gas in new homes and new furniture–how long will it take for levels to get back to normal? The best data I’ve seen suggests formaldehyde takes about two years to off-gas back to normal levels. Why We Need Real-World Tests on Formaldehyde […]
Why Formaldehyde Detectors Are Not as Effective at Measuring Formaldehyde as You Think
Lots of companies will sell you formaldehyde detectors, but a simple test you can do at home will reveal they are fakes. Formaldehyde detectors routinely react to lots of common gases that are not formaldehyde, making the numbers basically impossible to interpret. Given that unfortunate fact, here’s what you can do to test formaldehyde in […]
Does Closing the Windows Starve Us of Oxygen?
Air purifiers work best in a closed room environment, but this makes some people worry that closing windows starves us of oxygen. Yet recent tests in a real apartment — with as many as seven people in a small room — show less than 1% change in oxygen levels in a closed room. Fears […]
Which Gym in Beijing Has the Safest Air?
Even though PM2.5 levels are falling, years of bad air pollution across China has led to many people installing air purifiers in their homes. Most of us are now breathing cleaner air at home, but what about when we are in public spaces? What’s the air like in that gym we go to, or in […]
What Eats Airpocalypse for Breakfast and Doesn’t Cost Thousands of Dollars?
Four years ago, I was coughing through a Beijing winter and wanted some clean air. But all the purifiers I could find cost hundreds of dollars, so I strapped a filter to a fan I had at home and made my first DIY purifier. It wasn’t pretty, but I tested it with a laser […]
Is PM2.5 Worse on the Subway?
I wear a pollution mask in Beijing, and I’ve always taken it off when I get into the subway. That’s because I’ve always assumed air in the subway is better than outside. But am I right to take it off? I’ve heard a lot of Beijingers debating whether air in the subway is any better […]
Smart Air Indoor Air Quality Audit in 3ESpace
Date of audit: 27/05/2017 Audit conducted by: Yap Choon Khin Paddy Robertson Air quality monitor: Dyloc DC1700 Pro AirVisual Node Audit location: 3ESPACE, Beijing Jiaodaokou, Xinhua New Culture Building, 5th floor Air quality measurement outside premises: 115 µg/m3 Corresponding Air Quality Index (outdoors)[1]: 182 Air quality inside premises: 70 µg/m3 Corresponding Air Quality Index (indoors): […]
New DIY Purifier Design Increases CADR 15%
After I made my first DIY purifier, a design magazine called me up to interview me. I said, “You realize this has no design in it, right? It’s just a fan and a filter.” Now I actually have a design improvement! I’m calling it the DIY 1.1. The Problem The data shows the Original DIY […]
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