After launching the world’s most cost-effective purifier (the Sqair), we started testing how long the HEPA filters last. 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 […]
Clean Air Data & Blog
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 is Smart Air’s latest air purifier, The Sqair, a powerful air purifier when it uses a “weaker” H11 filter? Purifier companies market all different grades of filters. Lots of purifiers on Amazon and Taobao market H11, H12, and H13 HEPA filters. But which one is the best? It’s easy to fall into the […]
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 […]
Did Delhi’s Air Pollution Drop 25% in 2019? What The Data Says
The Delhi government and Delhi Chief minister Arvind Kejriwal announced Delhi’s PM2.5 air pollution was down 25% in 2016-2018 compared to 2012-2014. Yet there is doubt. Thewire.in, for one, expressed skepticism about this claim. As data-driven nerds, we wanted to let the numbers answer this question. So we dug into the Delhi PM2.5 data […]
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 HEPA filters capture nanoparticles?
Many big purifier companies claim only their HEPA filters capture nanoparticles, like this Molekule ad. Although this claim is false, even journalists repeat this myth. Why is this belief so pervasive? One reasonable explanation is that the definition of “HEPA” leads people down that route. For example, this definition on Wikipedia […]
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 […]
Hold on! Replacement filters cost more than buying a new air purifier?
Ever since Smart Air founder Thomas made his first DIY purifier, Smart Air has been telling the world that purifiers are needlessly overpriced. And ridiculously expensive replacement HEPA and carbon filters are one reason why. HEPA filters were invented over 70 years ago by the US government. There’s no patent, nothing fancy – they’re just […]