Exposure

Exposure is the combined risk of the current environment in .

Radiation, air-pressure (or rather lack there of) etc.

Once you delve far enough down, your "Exposure" warning meter will popup and initiate a ticking noise.

Best thing to do is head back up FAST.

To venture into highly "exposed" areas, craft armor with a higher exposure rating or seal the area you're in and use an O2 gen. Both are good ways to proceed.