Can you wash a HEPA filter? If so, how should you wash or clean a HEPA filter? These questions keep cropping up, as they’re just about the only remaining problem for HEPA filters. HEPA filters are almost perfect: they are backed by tons of scientific tests; they’re pretty cheap; they use about as much energy as […]
Author: Choon Khin
Choon Khin is a Smart Air engineer from Singapore, studying chemical engineering at the National University of Singapore
You Thought Rain Washes Away Pollution?
I’ve wondered whether rain decreases pollution for a long time because I’ve noticed two things: 1. Sometimes after it rains in Beijing, the sky is gloriously blue. When that happens, many people like me say, “Wow, the rain really washed away the pollution!” 2. But then sometimes it rains and rains, and the sky still […]
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): […]
How Much Pollution Do We Breathe Every Day?
How much pollution do we actually breathe in every day? Are masks or air purifiers more benefiting to our health? Do we really need both? The answer to this comes down to how and where we are spending most of our time every day. There are two possible theories: masks might seem more effective since when […]
With a Window Open, Air Purifiers Still Effective?
Will my purifier still be effective if I have a window open? New test data from Smart Air finds that purifiers can still meaningfully reduce particulate pollution in a room with a window cracked. Obvious Town: Purifiers Most Effective With Windows Closed No one doubts that purifiers are most effective with the windows closed. That’s […]
Beijing Air Pollution Drops With Northern Wind, Worsens With Southern Wind
A new analysis of pollution data shows that wind strongly affects Beijing’s PM2.5. The data shows that the best air pollution happens when there are northern winds. Why would northern winds help? North of Beijing is home to sparsely populated Inner Mongolia. Thus, PM2.5 in China’s capital tends to drop when the wind blows from […]
Is There Less Pollution on Higher Floors? How Living in a High Rise Affects Air Pollution
Living on higher floors of tall buildings isolates people from the world. Cars, streets, shaokao vendors—they’re all farther away. So does that mean PM2.5 air pollution is lower on the higher floors of buildings? The Tall Building Pollution Test Tristan from the Smart Air team tested this by taking laser particle counters from floor 1 to […]
Surgical Masks Surprisingly Effective Against PM2.5
There’s a fantastic educational poster from Greenpeace that I’ve seen in several places (for example, here on AQIcn). It offers great advice on masks that protect us from PM2.5, soot or wildfire smoke. But then it says this: “No effect” it says. But when I read the cited articles, I saw no tests of surgical […]
New DIY Design Increases CADR 15% – Supplemental Data
Methods Results were identical to my earlier tests of the Original DIY, Blue Air, IQ Air, Xiaomi, and Philips. Anna conducted the overnight tests in her 15m2 Beijing bedroom. Doors and windows were closed during the test (except for occasional opening during the first couple hours before bed—that random variation is one reason I use […]
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