After big improvement in 2018, new data shows China’s war on air pollution is slowing down. A Smart Air analysis of 2019 PM2.5 data for China’s 15 largest cities found that more than half saw worse air quality in 2019 than in 2018. Maps comparing average PM2.5 in December 2018 to December 2019 show a […]
Clean Air Data & Blog
The air purifier your office needs
Can a simple fan and filter really clean large spaces? Seven years ago, Smart Air started when PhD student Thomas strapped together a DIY air purifier to survive a polluted Beijing winter. Founder Thomas Talhelm’s first DIY air purifier Thomas published test data on the purifier showing that it worked, then shared to the world […]
How many trees need to be planted to solve Delhi’s air pollution?
When Delhi’s air pollution spikes, netizens in the nation’s capital often bring up the solution of planting trees. For instance, this user on the question-answer site Quora asks “how many trees does Delhi need to combat its air pollution problem?” However, environmental research suggests that planting trees are an incredibly inefficient way to reduce air […]
How long does the Sqair’s HEPA filter last?
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 […]
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 […]
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 […]