It is not reliably known for how long the materials were used in filters. Some World War II and Soviet Cold War gas masks contained chrysotile asbestos or crocidolite asbestos in their filters, not known to be harmful at the time. An asbestos-containing Russian GP-5 filter and a safe modern one in comparison.

Unused gas mask filters from World War II may not protect the wearer at all, and could be harmful if worn due to long-term changes in the chemical composition of the filter. Most gas masks have sealing caps over the air intake and are stored in vacuum-sealed bags to prevent the filter from degrading due to exposure to humidity and pollutants in normal air. Filters cease to provide protection when saturated with hazardous chemicals, and degrade over time even if sealed. Gas masks have a useful lifespan limited by the absorbent capacity of the filter. 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. 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. Examples of substrates include activated carbon, and zeolites. For example, if the target particles are positively charged, a negatively charged substrate may be used. Although some form of reaction may take place, it is not necessary the method may work by attractive charges. This can be used to remove both particulate and gaseous hazards. Some masks have one or two compact air filter containers screwed onto inlets, while others have a large air filtration container connected to the gas mask via a hose that is sometimes confused with an air-supplied respirator in which an alternate supply of fresh air (oxygen tanks) is delivered.Ībsorption is the process of being drawn into a (usually larger) body or substrate, and adsorption is the process of deposition upon a surface. Later, stronger polycarbonate came into use. Panoramic lenses were not popular until the 1930s, but there are some examples of those being used even during the war (Austro-Hungarian 15M). The later Triplex lens style (a cellulose acetate lens sandwiched between glass ones) became more popular, and alongside plain cellulose acetate they became the standard into the 1930s. Glass and mica were quite brittle and needed frequent replacement. The first gas masks mostly used circular lenses made of glass, mica or cellulose acetate to allow vision. Many filters provide protection from both types. Filters against specific chemical agents can last up to 20 hours.Īirborne toxic materials may be gaseous (for example, chlorine or mustard gas), or particulates (such as biological agents).

Most combined gas mask filters will last around 8 hours in a biological or chemical situation.

The gas mask only protects the user from digesting, inhaling, and contact through the eyes (many agents affect through eye contact). Most gas masks are also respirators, though the word gas mask is often used to refer to military equipment (such as a field protective mask), the scope used in this article. 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. Army soldier ( USAWC photo) Indian muleteers and mule wearing gas masks, France, FebruA Polish MUA gas mask, used in the 1970s and 1980sĪ gas mask is an item of personal protective equipment used to protect the wearer from inhaling airborne pollutants and toxic gases. 1915 Zelinsky–Kummant protivogaz, designed in 1915, was one of the first modern-type full-head protection gas masks with a detachable filter and eyelet glasses, shown here worn by U.S. A typical industrial-grade gas mask for hazardous chemicals and dust A World War I British P Helmet c. For peacetime uses, including masks designed to filter gasses and particles, see elastomeric respirator. For the mask used to inhale the gas through, see Mask § Functional masks.

Man dog gas mask