Gas masks, filters and bad air

Some air will kill you. A gas mask is something you wear in the Mask slot of your Clothing section (F2), and it is only as good as the filter screwed onto it and the seal on your face.

Bad air

• Smoke from fires, burning cars and wildfires: coughing, blurred sight, then it hurts. Indoors it pools. In the thick of it there is carbon monoxide too, and no filter stops that: a thudding headache and gray edges mean get out.
• Tear gas at the old riot lines outside police stations, and from a thrown Tear Gas Grenade: your eyes stream, then screw shut, and you can't sprint. It never kills, but it leaves you blind in a fight.
• Toxic gas at chemical leaks (an ammonia plant, leaking tank cars, a chlorine store at a water works, a hilltop processing plant, and the derailed train in the downtown Ashes near Legion Square): a sharp bleach smell, a burning chest, and death in under a minute in the thick of it. A pale haze hangs over each site, and at the derailment yellow skull-and-crossbones signs stand on every street into it.
• Rot gas over mass graves: coughing and a turned stomach. It won't kill you.
• Spores in the Red Fog, ash in the Ashes and radioactive dust in the worst places: a mask with a working filter keeps them out of your lungs.

The masks

• Half-Face Respirator: nose and mouth only, twin cartridges. Light and easy to breathe through, but tear gas and chlorine still get your eyes.
• Full-Face Respirator: an industrial mask with a clear visor and a 40 mm canister on the chin. Face and eyes, a good seal.
• Military Gas Mask: the best seal there is, a 40 mm canister on the cheek and a voice emitter, so people can still understand you.
• Surplus Gas Mask: old army rubber and round glass eyepieces. It leaks a little, fogs a lot and every breath is work. Better than nothing.
• Improvised Gas Mask: a rubber hood you make at a workbench, with a charcoal can on the front. It leaks round the jaw.

Filters

• P100 cartridges (half mask): stop smoke, dust, spores and tear gas particles, and no gas at all.
• Multi-gas cartridges (half mask): carbon for gases and vapors plus a P100 pad. Chemical leaks eat them in minutes.
• CBRN canister (40 mm): the best filter: particles and gas. About half an hour in the thick of a chemical leak.
• Surplus canister (40 mm): old stock, past its date. It stops less and runs out sooner.
• Improvised charcoal filter (40 mm): charcoal and cloth in a tin can. Some smoke and dust, no gas. Make one by hand.

Every filter wears out as it works, faster in thicker air. A particle filter clogs and gets harder to breathe through; a gas filter starts to let gas through near the end, and you taste it. Hover a filter to see how long it lasts in each kind of air.

Putting it on and changing the filter

• Wear the mask like any clothes (right-click, Wear). Drag a filter from your pockets onto the Mask cell in the Clothing section to screw it on, or right-click the filter and pick Screw onto your mask.
• Changing a filter takes a few seconds, and you hold your breath while the port is open. In gas your stamina drains while you hold it; run out and you gasp a lungful. Change filters in clean air when you can.
• Wear the mask and it goes on sealed; Take off removes it. Right-click the worn Mask cell to Pull down (it hangs at your neck, and protects nothing) or Put on (sealing it again takes several seconds), and to Check the filter. The mask's tooltip shows the filter and how much life it has left.
• The HUD shows the filter's life next to your health. Right-click the Mask cell to take the filter off.

Wearing one

• You hear yourself breathe through the valve, harder when you run, and a clogged filter makes every breath a fight. People near you hear it too, faintly, and your voice comes out muffled.
• In first person you look through the lens: it fogs in the cold and when you're winded, rain runs down it, and a badly damaged mask has a cracked lens that lets gas at your eyes.
• Sprinting costs a little more stamina, and you can't eat, drink or smoke with it on.

No mask stops carbon monoxide. In thick smoke, the only answer is getting out of it. See also Clothes, washing and scent and Looting: fire stations, police stations, military sites, labs and hardware stores are where masks and filters turn up.