Filtering facepieces protect from respirable dust, smoke, and aqueous fog (aerosols), however they offer no protection from vapor and gas. The classifying system consists of the three FFP classes, the abbreviation FFP stands for “filtering facepiece”. A respirator mask covers mouth and nose and is constructed of various filter materials and the mask itself. Their use is mandatory in working environments exceeding the occupational exposure limit value (OEL). This is the maximal concentration of dust, smoke, and/or aerosols in our breathing air that won’t result in harm to health. In case of transgression, respirator masks must be worn.