Community Question: AC-fresh air or stale?


My girlfriend insists that all air from outside is fresh air and stale air is what the air conditioning circulates.  

Personally, I believe that the AC has fresh air, because it comes from outside!

Which brings me to you, our Science Lion community, what do you believe?

Does the AC provide fresh air or do you need to crack open a window to get a taste of the fresh stuff? Comment your thoughts below!