@elosha

I'm also keeping my old masks, just in case there is another future shortage.

@rivm

Maar wat doe je eraan als je buurman hout stookt, omdat het goedkoper is dan gas?

@elosha

I think the government should give the expired masks away to the public. In a medical setting they can no longer be used, but if these masks make people wear a mask that normally do not wear a mask, I think you gained something.

@elosha

Here is another study on the effects of heat on the filter:

"The high temperature rapidly deteriorated the filter charges and caused a lowered electrostatic filtration efficiency. In a heated condition, the web became fluffier, yet it did not directly affect the pressure drop or mechanical filtration efficiency. "

So it seems the filter layers are quite sturdy.

https://journals.sagepub.com/doi/full/10.1177/15280837221119411

@elosha

I guess it depends on how risky the situation is where you go with your mask. A few minutes into a quiet shop, or hours on a busy train.

I would look for headbands for the busy train. But for a quick visit for the shop I use earloops.

@elosha

I now see it says N95, but the masks were used in France...

"Following the H1N1 influenza epidemic health crisis in 2009, France constituted a safety stock of one billion surgical masks and of 799.9 million FFP2 masks (equivalent to N95)."

@elosha

I found a study that looked at this for FFP2.

The masks were defective because of the elastic bands (but you can tighten these).

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7395218/