Air purifiers and air pollution are probably the last things that come to mind when thinking of Mongolia. But maybe it should be the first, given how bad the air there is.
I was living in Beijing during the airpocalypse, so I decided to buy an air purifier. Then I discovered how expensive they are! The air purifier I wanted cost $1,000!
I did some research and found out that all you need to remove particulate pollution is a fan and a HEPA filter. The HEPA filter is what captures the small sized PM2.5 particles. Even the $1,000 air purifier uses a fan and a HEPA filter to do just this! So I got my hands on a HEPA filter and strapped it to a fan to make own DIY air purifier:
Then I bought a laser particle counter and did tests comparing the DIY air purifiers to the expensive air purifier brands I could find on the market. Here’s what I found averaged over dozens and dozens of tests in my Beijing apartment:
All the testing methods and original data are publicly available–check it out!
After I discovered purifiers could cost just a fraction of what other companies in the purifier market wanted, I started a social enterprise I called Smart Air to help spread the word. My team and I have now shipped over 40,000 low-cost purifiers to people all over China. Woah!
Since then, I’ve received emails from several people in Ulaanbaatar, Mongolia asking if we can ship our purifiers there. I never knew how bad the air pollution is there!
But it’s downright terrible. The black line here is the average PM 2.5 in Ulaan Baatar (particulate pollution). The red line is what the WHO considers safe:
From 2008 to 2011 Ulaan Baatar averaged nearly 150 micrograms of PM 2.5! That’s worse than Beijing. In 2014, Beijing averaged 98 micrograms. The graph also shows huge PM2.5 peaks in the winter, and much, much lower. Here’s another graph from 2015 to 2018, showing the trends over 3 winters:
Why are Ulaanbaatar PM2.5 levels so high during the winter?
Most of Ulaanbaatar’s air pollution comes from coal. In the winter, people across Ulaanbaatar – from the gers in the suburbs to the government heating facilities – are burning coal. This creates the sooty, black pollution levels that start to rise in October every year, then drop off come March when temperatures start warming.
So I packed my bags, carted three huge boxes of fans and filters to the airport, and flew to Ulaan Baatar to host some DIY workshops!
New Mongolian owners of finished Original DIY air purifiers
With the help of several people in the capital, I hosted some workshops, and then subsequently launched Smart Air in Mongolia! Since then we’ve shipped air purifiers, masks and air pollution monitors to breathers across Ulaanbaatar, helping more people get clean air!
Do air purifiers work in Ulaanbaatar, Mongolia?
While I was there, I ran some tests to make sure the DIY air purifier works well in Mongolia too. Here’s what my bedroom in Ulaanbaatar looked like:
You can see the particle counter on the left and the DIY air filter on the right.
Here’s what happened to 2.5 micron particles after I turned on the DIY air purifier in my 15 square meter UB bedroom:
Here’s what happened to the smaller size 0.5 micron particles:
The two graphs show that after just 1-2 hours, the simple yet affordable DIY air purifier was able to filter out even the tiniest-sized 0.5 micron particles, it did just as well capturing the larger 2.5 micron (and above) particles.
The answer’s simple, it’s not difficult to prepare yourself for Mongolia’s winter air pollution season. Get yourself a simple DIY air purifier, and that’s it!
Breathe safe, Mongolia!
Thomas is an Associate Professor of Behavior Science at the University of Chicago Booth School of Business and the founder of, a social enterprise to help people in China breathe clean air without shelling out thousands of dollars for expensive purifiers.