Study Details Whether Your Old Face Mask Is Still Effective A Year Later

If you bought a pack of reusable face masks at the start of the pandemic and find yourself still using them more than a year later, you may be wondering whether they're still effective at helping reduce the spread of the virus. A new peer-reviewed study from the University of Colorado at Boulder confirms they are — with one big exception.

Generally speaking, a reusable cloth face mask is made from two layers of cotton stitched together and fitted with ear straps. These masks can be washed and dried with a load of laundry, making them cheaper and easier to use in the long run than buying packages of single-use medical masks.

The pandemic has led to a spike in medical waste, including a substantial number of discarded face masks. Reusable face masks help address this issue by reducing how many masks a single person will go through. If you've been using the same cloth masks since the early pandemic, it is safe to assume they're still adequately serving their function, at least according to the new study.

Researchers tested reusable cloth face masks with a steel funnel used to simulate breathing through the mask. They put the masks through up to a year's worth of washing and drying cycles, using them with the simulated breathing apparatus in between, to analyze how they hold up over time. As expected, the small cotton fibers began to come apart after many washing and drying cycles, but this didn't have a big impact on their ability to filter particles and reduce how far those particles can spread.

The researchers did note that older masks did exhibit a slight increase in resistance when inhaling, however; this means someone wearing an old face mask may notice a small increase in how hard it is to breathe with them on. The big 'catch,' however, is that a face mask's ability to filter particles is dependent upon a proper fit. If the mask has become stretched out and loose over time, leaving big gaps around the wearer's face, its effectiveness will decrease substantially.