Which mask works best on your face? I was fortunate enough to visit a lab to do a super fancy fit test, but very few of us have access to this $10,000 machine. So what should normal folks do?
While visiting the 3M lab, I learned about what I’m calling the poor man’s fit test. It’s not as accurate as a real fit test, but it will help you identify big leaks. It’s pretty simple:
- Put on the mask. Make sure the metal is bent tightly around your nose.
- If the mask has two straps, make sure one strap is below your ears and one above like this:
- Lightly hold the mask in place and inhale sharply. While inhaling, pay attention to see if you feel a sensation of air or coolness around the edge of the mask. Pay particular attention to the area around the nose.
- If you feel air leaking, adjust the mask and try again. If further adjustment does not solve the problem, try a different mask.
If your mask does not have an exhalation valve, you can also do the test while exhaling sharply.
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.