A gas mask is designed to go over the face to protect the wearer from inhaling “airborne pollutants”. The mask seals the nose and mouth and many times covers other soft tissues of the face. Some have respirators. Most gas masks provide protection from gaseous and particulate and are often used by riot police and rioters alike. They are also used by graffiti artists to protect them from the fumes.
The original design had two small glass eye windows that were thick in order from keeping the brittle glass from breaking. After polycarbonate was discovered gas mask started having big full-face windows.
Absorption, the process of being drawn into a body, is used to remove both particulate and gaseous hazards. Many time a electric charge is used to draw the particles in. To draw positively charged particles a negatively charged substrate is used. Many of these substrates include activated carbon. That is why putting a damp cloth over the mouth can filter out particles although not necessarily toxic gases that displace oxygen.
Since the filters have only so much capacity it is eventually saturated and the Gas mask is no longer useful. Older masks, such as those from World War II, may actually harm the user if used now. These masks used blue asbestos in the filters which was later found to potentially be fatal. There are many horror stories related to older gas masks where the filters have gone bad.
Modern masks are made of an elastic polymer and fitted with adjustable straps that are used to secure a good fit. It is connected to a filter near the mouth or through a flexible hose. Some models are connected to drinking water while others have corrective lenses for those that need them.
Masks are first tested for fit and then tested against chemical agents. During use the user holds their breath until the mask is on then breathes out hard to purge the inside of the mask of any contaminates. Then they check the edges for a proper seal.
Ancient Greeks used a sponge as a gas mask before Banu Musa invented a rudimentary gas mask to protect workers from polluted wells in the 9th century. Miners adopted primitive respirators in 1779. In 1849, Lewis Haslett created a “Inhaler or Lung Protector” which filtered dust from the air. The “Safety Hood and Smoke Protector” was another early design composed of a cotton hood with two hoses hund down to the floor allowing the breather to get the safer air near the ground. It also had moist sponges inserted at the end of the hoses in order to better filter the air.
On April 1915 the Germans were the first to use poison gas. The troops attacked used cotton mouth pads for protection and not soon after the British added a long cloth which was used to tie chemical-soaked mouth pads into place. The canister gas mask, which was connected to a tin can containing absorbent materials, was invented in 1916. James Bert Garner is credited by American sources as the inventor of the gas mask and after successful testing his mask was one of the first used in World War I.
Gas masks have developed alongside chemical threats and do well to protect the user from them, however, they do not protect against agents that can penetrate the skin. Often activated charcoal is a common component of gas masks. The carbon act as a bonding agent to any chemical pollutants that pass through the filter.