Gas mask

The gas mask is a mask used to protect the wearer from inhaling airborne pollutants and toxic gases. The mask forms a sealed cover over the nose and mouth, but may also cover the eyes and other vulnerable soft tissues of the face. Most gas masks are also respirators, though the word gas mask is often used to refer to military equipment (e.g. field protective mask). The user of the gas mask is not protected from gas that the skin can absorb. Most gas mask filters will last around 24 hours in a nuclear biological chemical (NBC) situation.US Navy MCU-2/P gas mask system.Gas mask used by the French military. The filter cartridge is connected via a flexible hose.Greek Infantry with US M17 gas masksA primitive respirator was designed by Alexander von Humboldt in 1799 for underground miningVarious gas masks employed on the Western Front and Eastern Front during World War IFinnish civilian gas mask from 1939. These masks were distributed during World War II The gas mask is a mask used to protect the wearer from inhaling airborne pollutants and toxic gases. The mask forms a sealed cover over the nose and mouth, but may also cover the eyes and other vulnerable soft tissues of the face. Most gas masks are also respirators, though the word gas mask is often used to refer to military equipment (e.g. field protective mask). The user of the gas mask is not protected from gas that the skin can absorb. Most gas mask filters will last around 24 hours in a nuclear biological chemical (NBC) situation. Airborne toxic materials may be gaseous (for example, sulfur mustard and chlorine gas) or particulates (such as biological agents). Many gas masks include protection from both types. Gas masks are used in construction to protect against welding fumes, in demolition to protect against asbestos or other hazardous particles, and in the chemical industry when handling hazardous materials, as in making repairs to leaking equipment or cleaning up after spills; workers are usually issued gas masks as a precaution against leaks. During demonstrations and protests where tear gas or CS gas is employed by riot police, gas masks are commonly used by police and demonstrators alike. Aside from serving their functional purposes, gas masks are also used as emblems in industrial music, with the most notable example, the subgenre of drum and bass called neurofunk. These emblems are used by graffiti taggers because the mask protects them from the paint canister's toxic fumes, and by urban explorers venturing into environments where hazardous materials, such as asbestos, may be present. The traditional gas mask style with two small circular eye windows originated when the only suitable material for these eye windows was glass or acrylic; as glass is notoriously brittle, glass eye windows had to be kept small and thick. Later, the discovery of polycarbonate allowed for gas masks with a large full-face window. Some have one or two filters attached to the face mask while others have a large filter connected to the face mask with a hose that is sometimes confused with an air-supplied respirator in which an alternate supply of fresh air is delivered. Absorption is the process of being drawn into a (usually larger) body or substrate, and adsorption is the process of deposition upon a surface. This can be used to remove both particulate and gaseous hazards. Although some form of reaction may take place, it is not necessary; the method may work by attractive charges. For example, if the target particles are positively charged, a negatively charged substrate may be used. Examples of substrates include activated carbon, and zeolites. This effect can be very simple and highly effective, for example using a damp cloth to cover the mouth and nose while escaping a fire. While this method can be effective at trapping particulates produced by combustion, it does not filter out harmful gases which may be toxic or which displace the oxygen required for survival.