A Gas Mask is a type of breathing apparatus designed to filter the various toxic gasses that pollute the air of the surface.
Gas masks are necessary for those who wander outside of the metro and out on the surface in the ruins of Moscow as the air is poisonous to any un-mutated organisms. The gas masks likely uses charcoal filters as charcoal is a natural poison absorbent.
All gas masks worn in the metro are full faced masks, most likely because the air is not only toxic to breathe, but also toxic to a person's eyes. The toxic atmosphere only seems to affect the user's respiration and not the user's skin because Artyom and many NPC's can go out to the surface whilst wearing fingerless gloves and having some parts of their skin exposed. After a while on the outside, Artyom will need to change the filters on the gas mask. The maximum filter time Artyom can have for his mask seems to be capped at around 30 minutes.
As Artyom takes impact damage due to melee attacks and bullet impacts, the gas mask will become cracked, the more severe the cracks become, the less time the filters will last. If the mask becomes broken, it must be immediately exchanged for a new one, or Artyom will suffocate. Gas masks can be found littered throughout the surface, since many people have traveled to the surface and ultimately died, their gas masks are still usable by Artyom. There are more than 5 different kinds of gas masks found throughout the game but Artyom seems to be wearing only the full-faced standard mask regardless of suit purchased. Even if his gas mask is severely damaged or completely broken he can only replace it with another full-faced mask. Strangely at the end of the game Artyom is seen with a ranger helmet and visor instead of the full-faced mask. If Artyom sprints or jumps the gas mask time will be affected.
- The gas mask used by the rangers in the game very closely resembles the Soviet M10, used by the Czech military of the USSR during the Cold War. Although many elements of the mask and its in-game counterpart look practically identical, there are two key differences. One is the visor and the other is the material. If the rangers of Metro 2033 do use M10 gas masks, then it must be a different variant - built-in to their helmets.
- With eyepieces and a voice diaphragm that are almost identical to that of the M10, the Soviet PMK gas mask was also very likely inspirational during the development of the ranger mask.
- The gas mask used by the player is most likely a Russian PPM-88 model (Stands for "Panoramic Industrial Gas mask" or "Маска панорамная промышленная").
- A mixture of different models from various nationalities can be seen in the game.
- The character on the box art of Metro 2033 is seen wearing a standard Nazi gas mask.
- If the player shoots the gas mask off of a Nazi while on the surface, the Nazi will immediately scramble to put on another, a clear full faced one like the one the player uses. If this one is shot off, the Nazi will suffocate and die or replace a new one, the replaced one will be unbreakable.
- In the game, if the gas mask becomes cracked, it reduces the air filters duration. In real life, a crack in the mask would not affect the filter at all; it would simply leak in poisonous air.
- The player can exploit the duration of the air filters by constantly putting on and taking off the gas mask. Since the player has a short period of time that he can go without a mask on, this time elapsed with the gas mask off can be valuable if the player is nearly out of time on his filter. This tactic shouldn't be used when the player has more than one filter however, since taking off the mask will swap the old filter with a new one.
- The gas mask filters the player uses are very large (bigger than Artyom's hand), but the filters appear very small before being picked up. They are likely 60mm filters.
- The player can damage unused gas masks by shooting, stabbing or hitting the glass.
- The Nazi gas mask and the ranger gas masks are the same, but the Nazi masks have filters and a helmet over them, while the Rangers' masks are attached to their helmets.
- By the time of the game, all gas masks and filters would be at least 20 years old. Most filters expire after 20 years, while gas masks tend to breakdown after 20 years. The masks and filters in game are either expired, close to expiration, or have been produced in the metro.
- Some Nazi gas masks seem more like the breathing devices used to prevent breathing toxic fumes from paint. Those devices are used by people painting with spray or auto refinishners.
- The filters can be changed manually by pressing (while mask on, not holding) the gas mask button.
- The gas mask used by Vladimir and Bourbon is identical to the one used by Artyom.
- Artyom's breathing can be slowed down by standing near a source of fire. At this moment, putting a new filter on would give a considerable amount of duration.
- Artyom's breathing will be faster while the filter is about to be changed, this is handy in Ranger difficulties, since the indicator on Artyom's watch can be hard to read sometimes.
- Artyom's mask becomes increasingly foggy with condensation as his filter runs out. This can be used as an easy means of telling how much time is left on a filter.
- In most cases, Artyom has about 30 seconds to find a new gas mask or a new filter before dying.
- Its possible for a glitch to occour where you are unable to remove your gas mask, but its filter lasts indefinitely. Switching gas masks with one on the ground fixes this.
- The player's gas mask also resembles a mask produced by Mine Saftey Appliances.
- One of the NPC gas masks resembles the A.F.M.34 gas mask made in the 1930s.