Gas

SS13's robust atmospheric system has been simplified, but you will still have to be wary of the air around you. To quickly check whether or not you can take off that gas mask, you can use an atmos analyzer or the built-in version on your PDA.

Gas comes in four storage containers: emergency tanks (can fit on the belt or in a pocket), ordinary tanks (can fit on the back slot), canisters (can only be dragged or picked up by the engineering cyborg module) and reserve tanks (fixed).

Note: Due to the utterly alien will of eldritch Atmos gods semi-convoluted but slightly sensible atmos system, you can't just repressurise a room simply by sticking a gas canister in there, or else all the gas will collect and stay in that one tile. Instead, move the gas canister around the room from time to time and hope that the gas evenly distributes itself then.

For vessel capacities and interactions, see Plasma Research.

Air

A mixture consisting of 79% N2 and 21% O2, or in other words what you are generally breathing. Spare canisters can be found in toxin research, emergency storage and the various air hookups. The high-capacity versions can also be ordered from Cargo through the Extra Large Air Mix Canister crate.

Note: Don't be tempted to top off your jetpack with regular air. You will have to increase your oxygen source’s release pressure, which will make it run out much faster, or else you will suffocate.

Oxygen

In the future, pure oxygen is safe to breathe! All roles start with a box containing a pocket oxygen tank while nuclear operatives start with an expanded version. Canisters are readily available in toxin research, engineering, EVA, Medbay's cryo treatment cells, and on the mining outpost. Tank dispensers have loads of these, and you might find some in those blue emergency oxygen closets. The oxygen vendor can fill up your tanks with this--for a price. The Spare Oxygen Canister crate that can ordered by Cargo contains a, well, canister of O2. By default, jetpacks also contain 100% O2. Butt Bots can output Oxygen to fix airless environments.

Note: Keep in mind that oxygen fuels fire.

Plasma

The true purpose of SS13's research. It is a purple gas that is highly toxic and highly flammable, hence breathing plasma is a bad idea. It is the main ingredient in making bombs, the Thermoelectric Generator, and/or and hellish station-consuming fires. Logically enough, plasma canisters are stored in toxin research and engineering.

Note: It's extremely flammable. Creating sparks or carrying any sort of lit object (welder, cigarette, cakehat) into a cloud of plasma will ignite it, setting off a fire that will quickly spread.

Carbon Dioxide

Invisible but deadly. Inhaling CO2 will make you cough, rapidly fall unconscious and suffocate if you're not moved to an area with proper atmosphere. CO2 canisters are available in toxins research and engineering.

N2

Part of the standard air mixture. It is an inert gas with little productive use. A couple of canisters start in toxin research and engineering, which spawn with a default temperature of 80 K or -193° C.

N2O

Knock-out or laughing gas, exposure to which will quickly render you unconscious. Recognizable by the white particles it leaves in the air. A canister can be found in the armory and the tanks in medbay's anesthetic locker also contain N2O.

Fart

Really. Fart gas is created when people fart, and it can be extracted from the air through air scrubbers. Too much fart gas in one place makes people vomit, and the gas potentially plays a small role in combustion. Butt Bots will produce fart gas when Emagged.

Gas Properties

Gas	Image	Isochoric Molar Heat Capacity (J/molK)	Ore Source	Brief
Plasma		150	Plasmastone	A material with Sci-Fi properties and interactions. A major NT goal is the study of this gas.
Oxygen (O2)		40	Molitz	A key ingredient for life. A key ingredient for fire.
Nitrogen (N2)		50	Viscerite	Typically inert. Makes up 80% of the station's atmosphere. Fresh canisters are often stored at 20 Kelvin.
Carbon Dioxide (CO2)		40	Char	A common byproduct of combustion.
Nitrogen Dioxide (N2O)		60	N/A	Also known as "sleeping gas". Surgeons of various repute are known to administer it.
Air (O2 + N2)		42	Molitz + Viscerite	Standard human atmosphere.
Farts		69	N/A	Human byproduct. Has interesting combustion properties.
Oxygen Agent B		300	N/A	Sourced in small quantities from rare Molitz Beta crystals and Molitz Beta geodes.
Fallout		5	N/A	Byproduct of neutron-exposed plasma.

Special Notes

• Molitz Beta crystals contain a lot of oxygen and a small amount of "Oxygen Agent B". When Molitz Beta is exposed to an environment above 500 Kelvin the trapped gasses bubble out. 15 moles of oxygen, 0.18 moles of agent B. The reaction is endothermic.
• When "Oxygen Agent B" is mixed with plasma and CO2 above 900 Kelvin:
  • Some CO2 is converted into O2,
  • A small fraction of Agent B is consumed,
  • Some heat is generated: 1000 Jules per mol Agent B consumed, and
  • A reasonable concentration allows fire to exceed 80,000 Kelvin.
• When farts are mixed with plasma and CO2 above 900 Kelvin:
  • Some CO2 is converted into plasma,
  • A small fraction of farts is consumed,
  • Some heat is generated: 500 Jules per mol farts consumed.
• Neutrons passing through a gas container (including a reactor gas channel) have a chance to react with the gasses. The neutron reactions are based on the type and density of the gas.
  • Plasma: 0.5 mol of plasma converts to 2 mols of fallout. Another neutron is created for each reaction that occurs. This can occur multiple times in dense plasma, producing lots of fallout and neutrons for just one input neutron.
  • CO2: 1 mol of CO2 and the neutron are destroyed, causing the gas mix's temperature increase by 5 Kelvin. This can absorb the neutrons from the plasma reaction above, if they are mixed.
  • Fallout: 1 mol of fallout and the neutron combine to produce a small amount of another random gas, while increasing gas mixture's temperature by 5 Kelvin. The neutron is not consumed.

---