A gas mask is a type of respirator that protects the wearer from harmful gases. They are used by military personnel and others in situations where dangerous chemicals may be present such as during chemical warfare or in the event of a nuclear catastrophe.
Gas masks filter out harmful substances in the air by using a small box connected to a breathing tube and fitted over the wearer’s head. The box contains granules that absorb poisonous gases and the inhaled air passes along the breathing tube to the wearer’s mouth. This system is much safer than other alternatives, which are usually prone to leaking and need frequent replacement.
The most common gas masks include an activated carbon filter for odour reduction. Carbon is most effective against organic compounds as it has a high molecular weight and low solubility (SentryAir). These filters are often layered between fibrous filter layers intended for particle filtration. Carbon filters will not, however, filter carbon monoxide or any other inorganic chemical.
Activated carbon filters also do not filter smoke, making it important to pair them with a particle or NBC filter. Like other respirators, they can be difficult to use over long periods of time and are not suitable for use by untrained people. They must be stored properly to maintain effectiveness. This includes keeping them in a dark, cool, dust-free place that is ventilated regularly and not subject to sudden temperature changes. They must be kept away from fuels, solvents, lubricants and electric machines which produce electric sparks. Potassium iodide tablets should be taken with the mask to prevent thyroid damage from fallout and excess radiation, and they must be stored in their foil wrappers. cbrn