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How To Make Your Own Air Purifier

Posted on July 6, 2023   |   Updated on September 30, 2025
Kaela Cote-Stemmermann

Kaela Cote-Stemmermann

All with just a few easy-to-find materials. (Michael Robinson Chávez / The Washington Post via Getty Images)

All with just a few easy-to-find materials. (Michael Robinson Chávez / The Washington Post via Getty Images)

Poor air quality has become a regular occurrence in D.C. this season, thanks to smoke from wildfires in Canada (and maybe just a couple fireworks). WTOP reports that the region will continue to see more serious haze in the coming weeks and months. Air purifiers can be expensive, so here’s how you can make your own at home with a few simple items.

🧰 Quick and Simple

Necessity is the mother of invention, so let’s start with the most simple version of a DIY air purifier.

  • Step 1: Get a square fan (most air filters are squares or rectangles, so we’re applying basic geometry).
  • Step 2: Buy a HEPA filter (shoot for one similar in size to your fan).
  • Step 3: Secure the filter to your fan via duct tape or packing tape, making sure to seal the connection as tightly as possible.

The New York Times’ Wirecutter created this filter. Their testing showed this simple version outperformed a fancy $800 air purifier!

👷 Take it to the Next Level

After covering the COVID-19 pandemic, The Washington Post reporter Lena H. Sun took it upon herself to build what’s called a Corsi-Rosenthal Box, which basically takes the version above and gives it superpowers. She has a great step-by-step guide on how to build one.

If you build one of these, we want to hear about it!

Share your DIY experience

Adapted from City Cast Editor Adrian González.

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