Can anyone explain why/how unused anti-viral masks degrade over time?
I have a number in a box I bought for the shop but they have an expiration date of 2010. I'm told they're better than nothing but not sufficient protection.
Seems strange that filters sealed in plastic would degrade.
tia
PS I see a number of ads for masks being sold as "anti-bacterial" but they do not list as anti-virus. Don't be mislead. Viruses are much smaller than bacteria.
I have no idea why a mask stored in a cool dry dark place wrapped in plastic would degrade. The rubber in the straps might degrade from Ozone if it's in sufficient concentration.
I bought a box of N95 masks some time ago and was down to three. Gave two to a friend who is working in some type of feeding operation. Lowe's and Home Depot have been out for months and are proud of the fact they gave their supply to front line people. All well and good, but it's been months. Time to gear up is over and they should restock.
I am amazed at how thin and fragile the supply chain is. How were they going to restock on things like Toilet Paper? You wouldn't think overall demand went way up, just a blip in the demand.
As far as masks go, who is waiting to gear up and start making them? Do they need permission to start? Wouldn't you think somebody at Home Depot or Lowe's would have been pounding on the makers to get some? I am tired of inhaling dust.
I go in twice a year for an exam for skin cancer. (Lots of family history) They put my next exam off for three months. They have never used any PPE during the exam. If I die of Cancer I am going to be pissed.
I've had the elastic fail on masks that are too old. I don't think the filtering material degrades. Honeywell provides this explanation of an N95 mask. Note that there is no electrostatic filter mentioned.
Here is a breakdown of what an N95 mask is:
N: This is a Respirator Rating Letter Class. It stands for “Non-Oil” meaning that if no oil-based particulates are present, then you can use the mask in the work environment. Other masks ratings are R (resistant to oil for 8 hours) and P (oil proof).
95: Masks ending in a 95, have a 95 percent efficiency. Masks ending in a 99 have a 99 percent efficiency. Masks ending in 100 are 99.97 percent efficient and that is the same as a HEPA quality filter.
.3 microns: The masks filter out contaminants like dusts, mists and fumes. The minimum size of .3 microns of particulates and large droplets won’t pass through the barrier, according to the Centers for Disease Control and Prevention (CDC.)
Material: The filtration material on the mask is an electrostatic non-woven polypropylene fiber.
Valve: Some disposable N95 masks come with an optional exhalation valve. “The presence of an exhalation valve reduces exhalation resistance, which makes it easier to breathe (exhale,)” according to the CDC.
The date has nothing to do with the masks actually degrading. N95 masks are classified as a medical item and as such the Gov't requires that they have an experation date. This comes from my wife's orthopedic surgeon.
First reports of those expired masks in the federal storage was that the elastic would degrade and fail to provide a secure seal at the edge of the mask.
Oxygen/ozone breaks down the elastomer used for the strap. They will crumble after some amount of time. The 3M expiration date gives an estimate of how long they will last under some "average" conditions. In a city with lots of ozone, less than other places.
What I have are pleated antiviral masks made by Curad that claim to have "inactivated" 99.99% of viruses including H1N1 when within their use-by period.
I've experience the breakdown of the yellow rubber bands on 3M N95 masks but I don't know how many years old those were. I had a newer box with maybe 7 out of 10 left. Being selfish and cautious I removed a few as an emergency supply since I am the sole caregiver of my very elderly mother and sealed each of them in a zip-lock bag along with gloves and a tiny hand sanitizer and then took the rest of them down to my local fire station. I've been using the disposable masks myself and being super cautious ever since, basically getting groceries once a week early in the AM and doing my exercise at a track where I don't get too near to anybody.
As for expiration I suspect that, like so many things in life, the corporate legal department said they had to do something as a CYA.
As others have commented, it's probably the elastic that degrades. Why, exactly, such a mask can't be renewed by simply replacing the elastic is beyond my understanding.
>>>A hypochondriac friend dug out her stash of 3M N95 masks and every elastomer band broke when she tried to wear them to go out.
I've had success in long-term storage things like rubber bands in sealed jars purged with nitrogen. I'm guessing the oxygen in the air degrades the rubber. Maybe that would have worked for the masks. Everyone keeps a tank or two of nitrogen around, right?
About a year ago I found a box in the basement that had a bunch of old things from the den. There was a stack of checkbook registers, with a rubber band around them, in a manilla envelope. They were dated 1984-87. The rubber band was as pink and flexible as the day it was purchased. I was impressed. No nitrogen, but no daylight either and vveerryy little air circulation.
