Technically, gas masks are designed to protect a person's mouth and nose area from all kinds of harmful smoke and microscopic particles. Also known as face-fitted PPE or personal protective equipment, they are used for a variety of reasons and situations. Because their goals vary, gas masks are also made in different styles.
There are several manufacturers that produce masks that cover the entire face of a person. The type of protective equipment allows air to pass through the filter before the person breathes in. Gas masks are now often used as costumes for various theme parties or for any other less serious reasons; however, this protective equipment was heavily used way back during the Second World War.
However, protective gear continues to be an important item in the kit of any modern soldier. The modern army is still required to supply their troops with full-face gas masks just in case they face any threat and dangerous biological weapons that come from their enemies and terrorists.
This protective equipment is also used for industrial purposes. Having fun with it for industrial purposes is rather difficult as it can cost a lot of money. Respiratory protection, face masks as well as various other protective equipment are often required in most industrial settings by specialized industrial hygiene.