Gas masks are generally used in emergency situations. They are employed to safeguard the wearer from poisonous or potentially harmful fumes. This safety equipment is issued to many people including firefighters in industry, and soldiers in warfare.
The initial military gas masks were utilised in World War I, The device was basically a mask which was fitted over the face. It had a tube which lead to a canister carried on the back. The wearer breathed through the tube in his mouth and as an extra precaution a nose clip was used to deter the user from breathing through his nose. The canister contained charcoal, which allowed the harmful elements to be filtered out of the air.
By the time World War II arrived, the gas mask had been greatly improved. It became less clumsy and therefore considerably easier to use. With the mask fitting better, the nose clip was soon eliminated. The canister also changed its position. Rather than being on the soldier's back, it was placed on the side of the wearer. The advantage of this was that the soldier could keep a lower profile when under fire.
In the 1960's, the armed forces of the United States began to use a revised form of gas mask called the M-17. This type of mask excluded the necessity for the canister and tube. The substitute was pads of charcoal and filter paper, which were situated in the nosepiece to act as a filter.
Gas masks can utilise fibrous filters made up of many sorts of material, one example being cellulose. These are used to filter droplets of hazardous atoms and moisture. However, it is the charcoal which is the most significant material as it performs the job of filtering and purifying the air which has to enter the lungs.
