KW per cm2 would be fine. I know intuitively what is an inch, a pound, a KG and a cm, but I do not know what is normal atmospheric pressure (except I know as a trivia question that it's 15ish PSI). It's like a fish doesn't know what it is to be wet.
Pressure matters when it pushes on something, so you want to know what will be the force based on the size of the something...
