Self-filtering protective masks are a type of mask that covers the nose and mouth and serves to filter particles from the air, according to European standards EN 143 and EN 149. They are used in industry and as respirators/surgical masks, as well as in epidemics, to prevent contagious and hospital-acquired diseases. There are three types with different levels of protection: FFP1, FFP2 and FFP3. However, it causes small long-term health problems, such as dry eyes, due to exhaled air that rises to the eyes, or dry skin.

The European standard EN 143[1]​ defines masks by the type of particle filters that can be attached or characterized to a surgical or industrial facial mask: P1 (80% filtering), P2 (94% filtering), and P3 (99% filtering).[2]​.

Both European standards EN 143 and EN 149 test the penetration of filters with dry aerosols containing sodium chloride[3]​ and paraffin oil after storing the filters at 70°C and -30°C for 24 hours each. The standards include tests for mechanical strength, breathing resistance and obstruction. EN 149 tests the inward leakage between the mask and the face, where ten human subjects perform 5 exercises each and for 8 individuals the average measured inward leakage should not exceed 22%, 8% and 2% respectively.[3]​.

The European standard EN 149 defines the following classes of "filtering half masks" (Filtering Half Masks) or "filtering face pieces" (FFP), that is, respirators constructed entirely or entirely of filtering material:.