We did a test for a completely new 9332 mask and my 11-day-old 9332 mask. The results showed a 98% efficiency rate even after 11 days’ usage is pretty good! This contradicts the idea that you can only use these for a day or two. Our guess is that air pollution masks last at least two weeks.
Click here to read more: https://smartairfilters.com/en/blog/how-long-masks-last/