Awareness doesn't have to be "measured". Are you being asked to measure it, or is this just your thoughts on what you should do.
Awareness is best (IMHO) determined during internal audits, although it's also a supervisors best 'weapon' to avoid (quality, safety, environmental)disasters.
Simply going and asking people what they know about topic 'X' is the best determinant. It's a bit like finding out what your kids know about road safety - they should be able to give you 'chapter and verse' about crossing the highway, riding a bike, driving the car - whatever is appropriate and applicable to their situation.