A gas mask is a piece of personal protective equipment that filters chemical gases and possibly particles from the air you breathe. It covers the nose, mouth and sometimes eyes and can be worn with a hood. It has straps that secure it to the face and may be connected to a tank of oxygen (called a self-contained breathing apparatus or SCBA) via a flexible hose.
It is important to note that a gas mask, even one that has been properly fitted and used, will not protect against all hazards. The chemicals or materials that the mask is designed to filter from the air will still attack a person through skin contact, inhalation and eye exposure. Therefore, some type of additional protective clothing is needed in many situations where chemical warfare weapons are a threat.
In addition, wearing a gas mask can be difficult and uncomfortable for some people. Some people with claustrophobia, asthma or other lung diseases may have difficulty breathing while wearing one and should avoid doing so if at all possible. Some people who wear glasses may have trouble seeing while wearing the mask. It is important to have a fitting test and proper training before using a gas mask to ensure that it works as intended.
The most common types of gas masks for sale are elastomeric masks, which have adjustable straps and a flexible polymer that fits around the face and ties behind the head. They are connected to an air filter cartridge near the mouth by a flexible hose or directly, depending on the model. Some have drinking tubes for water and some have lenses to correct vision.
Cartridges or filters are sold separately for each chemical hazard that a gas mask is designed to filter out of the air. A single cartridge is usually good for about 8 hours of use in a CBRN (chemical, biological, radiological and nuclear) scenario. They may be filled with activated charcoal, a special filter for certain biological agents, or a mixture of both.
A more advanced type of gas mask is the self-contained breathing apparatus, or SCBA, which has its own air tanks that allow a person to operate without needing to remove the respirator. These are typically heavy (30 pounds or more) and require specialized training to use and maintain correctly. They can also be more expensive than other types of gas masks.
It is important to remember that gas masks, even the most sophisticated models, only provide protection if they are used with the correct filters and only if they are correctly adjusted and maintained. In addition, the gases or particles that are being filtered may be dispersed as true gases or as particulates, which will affect the wearer differently. The sensitivity of different chemicals to these two modes of action makes it impossible to design a single device that can protect against all potential toxic substances. As a result, the vast majority of military-issued gas masks are designed to filter for specific chemical-warfare threats.
