Particle filtering half masks (FFP masks) are items of personal protective equipment (PPE) within the scope of occupational health and safety and are intended to protect the wearer of the mask from particles, droplets and aerosols. Of course, these masks can also be worn in private surroundings. FFP stands for Filtering Face Piece. There are three filter levels: FFP 1, FFP 2 and FFP 3 The design of the particle filtering half-masks is different. There are masks without exhalation valve and masks with exhalation valve. Masks without a valve filter both inhaled and exhaled air and therefore provide both self-protection and external protection, although they are primarily designed for self-protection only. Masks with a valve only filter the inhaled air and therefore offer no protection against foreign bodies. They therefore make no sense in dealing with the corona pandemic, but are helpful in demanding, toxic working environments by making it easier to exhale.