What is the difference between the FFP1, FFP2, FFP3 mask?

FFP stands for filter face protection, the numbers 1,2,3, increasingly indicate the protection they offer.
The FFP1 mask filters about 80% of the particles suspended in the air and are used in working contexts. Even if they have a filtering power the size of 0.6 micrometers, they do not guarantee a correct protection against particles the size of a virus.
The mask FFP2 and FFP3 filter respectively about 94% and 99% of the particles in the air. They are admittedly more functional for containing the virus.
The masks FFP1, FFP2, FFP3 can have from 4 to 6 layers, equipped with elastic for the ear and a three-dimensional shape that favors the adherence on the face.
They can be:
- WITH VALVE: from protection to the wearer
- WITHOUT VALVE: it has its filtering action both in the respiratory and expiratory ways