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. A Polish MUA gas mask, used in the 1970s and 1980sĪ gas mask is a mask used to protect the wearer from inhaling airborne pollutants and toxic gases.