A Guide On Using Expired Masks.
By Breathe Free IE.
"Why Mask Blocs May Have Expired Masks."
Due to government failures to consistently & effectively respond to pandemics & climate disasters, community members all over the world have formed Mask Blocs to provide free PPE to people. Oftentimes, that means they’re running to the best of their ability with the help of community support. That might mean sometimes the only respirators available to provide to our communities are expired or close to expiration. But that doesn’t mean those masks can’t be effective.
"Why Do Masks Have Expiration Dates?"
Disposable masks have a marked expiration date that tells you when they’re best to use because they can become less effective over time. However, research has been done to determine how effective a mask can be once past or near expiration. We'll give a brief look at some of that research, which focuses primarily on N95's.
“What Makes a Mask Less Effective After Its Exp. Date?"
A mask might become less effective because elastic bands & nose pieces may degrade over time, especially if they’re not stored in the original packaging & proper climate. If this happens it can affect the fit of the mask. The fit, along with filtration, is what makes a mask effective, so if the seal/fit on an expired mask is right, it can still offer some protection.
"How to Get the Fit Right on an Expired Mask."
First, ensure face covering itself is intact. Check straps. If elasticity is still good, getting a good seal will be like the normal fitting process for a new mask. If straps have lost elasticity, you can use earloop-to-head-strap attachments/adjustable straps to secure it. If using expired masks, a good practice might be carrying an extra mask or carrying strap attachments in case straps loosen or break.
"How Well Will an Expired Mask Filter?"
A small study by researchers from the University of North Carolina & the EPA tested new & 16 yr old 3M N95 masks that were 10 yrs past expiration. They found that the expired masks were within 1% as effective as new masks.
"How Well Will an Expired Mask Filter?"
A summary of one study,put together by Mask Bloc East Bay, says most N95's maintained filtering ability.
"1. Inhalation and Exhalation Resistance and Filtration Performance of Stockpiled Air-Purifying Respirators: Overall Performance of Nearly 4,000 Respirators Sampled from Ten Stockpile Facilities. NIOSH NPPTL, 2020. Summarized here. 3971 expired respirators (172 P95, 3799 N95) from 10 US stockpile facilities were tested. The respirators were manufactured between 2003-2013 and tested in 2018-2019. 98% of the expired respirators maintained their inhalation and exhalation resistance and filtration performance in accordance with NIOSH performance standards. Pros:Tested a large number of respirators from geographically dispersed facilities with various storage conditions. Respirators had known manufacture dates. Cons: Not sure how poorly the 2% that failed did. The test used does not account for face fit and integrity of nose pieces or straps."
"How Well Will an Expired Mask Filter?"
Another study showed that even when there was a reduction in filtration, expired masks still performed better than new surgical masks.
"2. Beyond Shelf Life/Stockpiled Assessment Results
by the National Personal Protective Technology Laboratory (US), 2020 Data summarized here. Tested stockpiled N95 masks across the US that were approaching or beyond their expiration dates. The masks were either NIOSH-approved at the time of testing, or were approved in the past. Filtration efficiency was tested with TEB-APR-STP-0059, the testing procedure for N95 masks.
Result: The expired masks filtered between 69-99% of particles. 95% is needed for an N95 to pass. That means while some of the expired N95’s didn’t perform up to the N95 standard, most performed better than a new surgical mask. (See studies below for new surgical mask performance.) Pros: Tested a variety of brands and styles of N95’s
Cons:
Unknown authenticity, storage conditions, and expiration dates
The test used does not account for face fit and integrity of nose pieces or straps."
"How Well Will an Expired Mask Filter?"
This study showed that expired N95's can filter similarly to new N95's and also better than new surgical masks.
"3. Filtration Efficiency of Hospital Face Mask Alternatives Available for Use During the COVID-19 Pandemic
Sickbert-Bennett et. al, 2020. Tested fitted filtration efficiencies (FFEs) using OSHA’s Quantitative Fit Testing Protocol for Filtering Facepiece Respirators on “an adult male volunteer (weight, 75 kg; height, 178 cm; head circumference, 58.5 cm) with no beard”. Both expired N95’s (98.5% and 97%) performed similarly to the new N95’s, and much better than the new surgical mask with earloops (38.1%). Below that is a chart with images of each mask type and the previously mentioned percentages. Below that is text that says "Pros: Tested as worn on the face, so takes into account the performance of nose pieces and straps. Cons: Only two models of N95’s and one model of surgical mask with earloops was tested. Masks were only tested on one person.
"Key Takeaways."
An expired mask doesn’t necessarily mean an ineffective mask.
Usually expired masks perform well, as long as face covering itself, straps & nose pieces are undamaged & good seal can be secured.
If straps are damaged, masks can be resecured with strap attachments.
Even expired masks that no longer filter particles at original percentage filter much better than new surgical masks.
Sources:
“Do Face Masks Expire?
https://smartairfilters.com/en/blog/do-n95-masks-expire
“Studies on the safety of expired N95’s (compared to new N95’s and new surgical masks)” by Mask Bloc East Bay