Some other, random, but applicable rules:
SMOKE EFFECTS
A character who breathes heavy smoke must make a Fortitude save each round (DC 15, +1 per previous check) or spend that round choking and coughing. A character who chokes for 2 consecutive rounds takes 1d6 points of nonlethal damage.
Smoke obscures vision, giving concealment (20% miss chance) to characters within it. Smoke grenade smoke gives a %50 miss chance and full concealment.
HOLDING BREATH
A character who has no air to breathe can hold her breath for 2 rounds per point of Constitution. After this period of time, the character must make a DC 10 Constitution check in order to continue holding her breath. The save must be repeated each round, with the DC increasing by +1 for each previous success.
Night Vision Goggles
Night vision goggles use passive light gathering to improve vision in near-dark conditions. They grant the user the ability to see in darkness, also called darkvision- but because of the restricted field of view and lack of depth perception these goggles provide, they impose a -4 penalty on all Spot and Search checks made by someone wearing them.
Night vision goggles must have at least a little light to operate. A cloudy night provides sufficient ambient light, but a pitch-black cave or a sealed room doesn't. For situations of total darkness, the goggles come with an infrared illuminator that, when switched on, operates like a flashlight whose light is visible only to the wearer (or anyone else wearing night vision goggles).
