Respirators protect the wearer from inhalation of harmful contaminants, such as gases, vapors, or fumes. There are three different types of respirators: an air-purifier, an air-line or air-hose respirator, and a self-contained breathing apparatus (SCBA), also known as scuba equipment for underwater applications.

Respirators are used by the military, by health and safety organizations, by manufacturers of hazardous chemicals or compounds, and by construction companies. Respirators may be as simple as a half mask respirator that goes over the nose and mouth only or a full body suit with a helmet and a separate air supply. An air-supplied respirator includes biohazard suits that provide the wearer with a portable air tank. A full face respirator covers the entire face and also protects the eyes and face from irritants or debris. A welding helmet with a respirator protects the welder from hot gases that may be produced from torch cutting, brazing, or soldering. A welding respirator must be properly integrated with the welding helmet to ensure maximum visibility as well as provide a tight seal to the face.

Respirators are used when working with particulate matter, such as in powder coating or painting, mining, sanding and grinding, and asbestos abatement applications. A respirator face mask covers the entire face to keep particles from entering the lungs. A respirator mask used for protection from particulate matter is an air purifier, and typically comes with a filter or respirator cartridge that is replaced periodically. These disposable respirator cartridges lock into place and are rated by their ability to protect wearers from vapors and gases, mists and particulate matters, dust, and other contaminants. A paint respirator or gas masks are common types of respirators that use replaceable cartridges and canisters. Respirators may also be used in emergency evacuations. An air respirator can protect against tear gas and other biological or chemical agents.