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How to Make Your Own Air Purifier

Posted on August 20, 2024   |   Updated on September 30, 2025
Adrian González

Adrian González

The components of a homemade air purifier.

Did you know you can DIY an air purifier? (Michael Robinson Chávez/The Washington Post via Getty Images)

In Pennsylvania, hay fever season usually hits in August and September — so if you’re part of the estimated 15.5% of Americans who are sensitive to ragweed pollen, you may not be feeling great right now.

If those pesky allergens are bothering you even when you’re indoors, an air purifier may help you find some relief. Air purifiers can get expensive, though, 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: Acquire a square fan (most air filters are square or rectangular, so we’re applying basic geometry).
  • Step 2: Get yourself 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.

▶️ Follow along with this tutorial from the New York Times’ Wirecutter. 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.

🤧 More Allergy-Proofing Steps

Still sneezing? The Pennsylvania Department of Environmental Protection has some tips on how to reduce your exposure to ragweed pollen, and we’ve got some advice on how to keep allergies at bay inside your home.

Hey Philly newsletter editor Asha Prihar contributed to this article.

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