After launching the world’s most cost-effective purifier (the Sqair), we started testing the HEPA lifespan. I’ve long been skeptical of the lifespan numbers purifier companies give because (1) they provide no empirical justification for the number and (2) they give the same numbers in Switzerland or Delhi. Yet clearly the HEPA would last less time […]
Author: Thomas Talhelm
Thomas is an Associate Professor of Behavior Science at the University of Chicago Booth School of Business and the founder of Smart Air, a social enterprise to help people in China breathe clean air without shelling out thousands of dollars for expensive purifiers.
How Long Do Pollution Masks Last? | New Data
Scientific tests have found that simple pollution masks are incredibly effective, but how long do masks last? Most tests are done with brand new masks, so there’s very little data on used masks. And in that data vacuum, people have wildly different ideas about how masks remain effective. I’ve seen several people say they only […]
Why a weaker filter actually makes a stronger purifier
Why does Smart Air’s latest air purifier, The Sqair, use a weaker filter–an H11 HEPA compared to the H12 and H13 HEPA filters out there? Tests of different filter grades revealed that weaker filters sometimes make stronger purifiers. Of course, purifier companies like to market their filters as top grade. Lots of purifiers […]
Why The Sqair will transform the market for clean air
In 2013, I made a DIY purifier to get through an apocalyptic Beijing winter. The DIY wasn’t pretty, but it worked. Hundreds of days of tests showed it cut tiny 0.5 micron particles in my bedroom by an average of 84% (1, 2, 3). The DIY proved that air purifiers don’t have to […]
How effective are kid’s masks at filtering air pollution?
As cities like Delhi, Beijing and Manila face toxic levels of air pollution, people are rushing to find effective pollution masks, particularly for children. But there’s a problem. Children’s faces are different from adults’. Add to that, children are constantly growing, meaning that the mask that fit last year might not fit this year. Children’s […]
How many trees need to be planted to help to solve China’s air pollution?
Planting trees would be a very inefficient way to clean air pollution. Let me break down the effect of trees into (1) sucking up particulate and (2) giving particles a place to land. 1. How much particulate air pollution do trees suck up? Let’s talk about the most commonly talked about pollutant: particulate pollution (PM […]
Can you clean a car air filter with compressed air?
Working on DIY air purifiers for over 6 years, I’ve heard from a lot of people who have strong intuitions about cleaning car air filters. People tell me they wash their vehicle’s air filter, vacuum it, or bang it really hard. Opinions are plenty, but what about real, hard data? Can you clean air filters […]
Can air purifiers kill dust mites?
Dust mites look scary. And apparently they’re probably in my home, since they’re in most people’s homes. A survey found dust mites in 84% of US beds and 68% of European beds. Yet it’s hard to know for sure whether they’re in our homes or not because they’re mostly too small to see […]
What is the difference between the PM2.5 and AQI measurements?
There are some good answers here Richard Muller and Sandeep Chowdary. I’ll add a bit more explanation about PM 2.5 AQIs and a funny quirk about how they are calculated using stepwise linear functions. How is PM 2.5 AQI calculated? (Note: this is for the US AQI scale. We’ll be discussing different countries’ scales […]
PM10 vs PM2.5 – The Difference in Particle Air Pollution
Does size matter? The difference between PM10 and P 2.5 is size. But let me back up. “PM” refers to particulate matter—particles in the air. Those particles are things like organic dust, airborne bacteria, construction dust, and coal particles from power plants (for example, check out this study from researchers in Shanghai who analyzed what […]