Safety is the state of being "safe" (from French sauf), the condition of being protected from harm or other non-desirable outcomes. Safety can also refer to the control of recognized hazards in order to achieve an acceptable level of risk.
So it is with air: there is the brightest variety which we call aether, the muddiest which we call mist and darkness, and other kinds for which we have no name...
Some people talk as if meeting the gaze of absolute goodness would be fun. They need to think again. They are still only playing with religion. Goodness is either the great safety or the great danger — according to the way you react to it.