Smart Air Filters

DIY1.1 & Cannon air purifiers

DIY Purifiers

We’ll send you a fan, HEPA filter, and a strap for as little as 228RMB. Get these simple yet effective DIY purifiers and clean air in your lungs today.

DIY Filters »

Blast & Blast Mini FFU Air Purifiers

The Blasts

Stronger fans, bigger filters, lower particle counts, and faster clean air. If you’re looking to clean a larger area, check out the powerful yet quiet Blast air filters.

Click to Blast »

DIY1.1 HEPA Filter

HEPA filters

HEPA filters are what trap small particles like PM 2.5, and they’re not expensive! We’ve tested hundreds of different types, and get ours straight from the factory so we can pass the savings on to you.

Why use a HEPA? »

Free education and data on air pollution


We think if more people knew how purifiers work, they’d think twice about paying big bucks for clean air. Check out the Smart Air blog, attend a Smart Air workshop, or:

see the data »


Featured Press


BBC News

“The budget innovation has caught the imagination among residents who battle high levels of air pollution every day.”

See the episode


“At about $15 a HEPA, that’s a lot of savings over big international brands like Philips with comparable results.”

Read more


“They’re very creative. They have found an easy way that people can accept. I think the price is the key point. It’s so cheap.”

Read more


“Using a HEPA filter strapped to a simple flat-surfaced fan, he found that the device reduced indoor levels of PM 0.5 by 84 percent and indoor levels of PM 2.5 by 92 percent.”

Read more

Introducing the Smart Air DIY Air Purifier


Purification Effectiveness

Average % reductions of DIY 1.1 in 8-hour tests in a 15 sq-m bedroom.

Air Purification Speed

Based on an 8 hour test in a 15 sq-m bedroom.



Does the Smart Air DIY Purifier work?


Short answer: Yes!

Long answer: Keep reading


Let’s break down this question into three smaller questions:







1. Is the air coming out of the Smart Air DIY air purifier clean?


This is the easiest question to answer, and we do it by holding a Dylos DC1100 Pro particle counter in front of the purifier and watching the numbers drop. Here’s a video of Thomas doing just that:

(Can’t see the video? Watch it on YouTube or Youku).

Conclusion: Yes, air coming out of the purifier is clean.




2. Is the Smart Air DIY air purifier able to actually clean the air in the entire room?


Answering this question is more difficult because you need a controlled environment (for example, you don’t want to walk in and out of the room during the test), and you need to test the air for a longer period of time. But fortunately for you, Thomas is a huge nerd and does this kind of thing for fun.


To answer this, Thomas set up the particle counter on one side of his 13.5 m2 bedroom and put the DIY filter on the opposite side of the room. Here’s what our filter did in one hour:



And over the course of eight hours:



The particle counter also gives data on .5 micron particles — even smaller than the 2.5 micron reading. Here’s what that looks like over eight hours:


Conclusion: Yes, the clean air from the DIY filter is cleaning the entire room.





3. How well does the Smart Air DIY air purifier perform compared to expensive air purifiers?


Thanks to kind souls who donated a BlueAir 203/270E (3,600 RMB), a Philips AC4072 (3,000 RMB), and an IQAir Health Pro (8,000 RMB) we’ve finally been able to test the DIY against expensive brands in the same room, for the same amount of time, with the same particle counter.

To do that, Anna ran 11 overnight tests with the BlueAir, 9 tests with the Philips, and 11 tests with the IQAir. Thomas calculated effectiveness as percent reduction in particulates from the room air. Anna tested the air before she turned on the air filter, and then set the particle counter to take hourly measurements of the air in her 15 m2 Beijing bedroom. Anna used the highest setting on each filter.

Air purifier effectiveness comparison


All of the filters significantly reduced particulates, but the 470RMB Cannon removed as many particles as the highest-performing big brand. Even the 228RMB DIY 1.1 was only 4% behind the Blue Air on the .5 micron particles and 4% behind on the 2.5 micron particles.

Among the different brands, there seems to be no relationship between price and particulate removal:


Conclusion: You can remove particulate pollution from the air in your home and pay far less than the cost of a Blue Air, Philips, or IQAir.



4. Which purifier is right for me?

DIY 1.1

The Cannon

228 RMB

470 RMB

Original Cannon

The Cannon Cleans Faster

Based tests with a source of 0.5 micron particles. Get the full story here.

The Original

The Cannon

Suitable for normal-sized rooms (< 15 m2).
Quieter than the Cannon.

Suitable for larger spaces (at least 30 m2)
and anyone wanting clean air fast.