Filters for Face Masks. Five layer PM 2.5 filter for use in face masks. These have non woven and activated carbon layers to help filter out dust and things such as exhaust fumes. The PM 2.5 stops Particulate Matter larger than 2.5 micrometres, much, much smaller than a human hair, an individual Covid 19 is smaller than this.
Regardless of this I still use these filters in my own face mask. All the masks I have made that are available for sale here are three layers so adding an extra five layers I feel gives me, you, and anyone around us, a little more protection.
Now, as to how long they last. I cannot give a definitive answer on this as the suppliers give anything from a few hours to a week with an average seeming to be from 48-72 hours. I change mine if it gets damp or every couple of days depending on how long I have worn my mask and how many people have been around me, but this is my personal preference, yours may vary.
Filters are non-returnable due to health and hygiene reasons
If you have found me via the local e-bulletins you are welcome to collect to save on postage, contact me direct rather than going through order system