A respirator is a device designed to protect the wearer from inhaling hazardous atmospheres, including particulate matter such as dusts and airborne microorganisms, as well as hazardous fumes, vapours and gases. There are two main categories: the air-purifying respirator in which respirable air is obtained by filtering a contaminated atmosphere, and the air-supplied respirator in which an alternate supply of breathable air is delivered. Within each category, different techniques are employed to reduce or eliminate noxious airborne contaminants.
Air-purifying respirators range from relatively inexpensive single-use, disposable face masks sometimes referred to as a dust mask to more robust reusable models with replaceable cartridges often called a gas mask.