A gas mask is a piece of face equipment that filters out toxic and dangerous gases, while also blocking out dust and particulates. It usually covers only the nose and mouth, although it may also cover the eyes and other soft tissues of the face.

The first gas masks were invented in World War I, when the British army needed a way to protect soldiers from chlorine and other deadly gases that could be used by German forces as weapons of war. The principal medical officer of the 1st Newfoundland Regiment, Cluny Macpherson, is credited with inventing the gas mask. He developed a plastic shell that fit over the face, with a filter to block out harmful gases.

Most current military masks also include an activated carbon filter that can reduce odors and pollutants. However, carbon filters have a limited lifespan and will eventually become ineffective once the surface area of the carbon is filled up with contaminants. In addition, if a mask doesn’t fit properly (and be properly fitted with the help of fitting tests), the air leakage will outweigh the benefits of the carbon filter and it won’t provide any protection against chemicals or odors.

There are also specialized self-contained breathing apparatus, like those worn by firefighters, that use their own air tanks and don’t need to be plugged into anything else. They are much heavier, and require specialized training and maintenance to operate. They are also expensive and can take up to an hour to recharge. gas masks for sale