A respirator is a protective device used to prevent gaseous substances and fine particles from entering the body through the airway. These are often used in occupations such as carpentry, construction, chemical manufacturing, and others fields where airborne hazards may be present. Note that gas masks almost always have respirators built in, but not all respirators are gas masks. If there is no covering on the upper portion of the head, only tag with respirator and not gas_mask.