Thanks for the question Katy. The difference between inhaled air is simple. The air that you inhale is the same as the air around you in the atmosphere. It is 79% nitrogen 20% oxygen 0.03% carbon dioxide and is dry. When you breathe this air in, the air picks up moisture from the moist surfaces of your mouth and throat, the air becomes more humid (wetter). When the air reaches you lungs, some of the oxygen is taken out and put into the blood so that your body can use the oxygen to help it survive. When the oxygen is taken out by the body it is replaced by carbon dioxide from your body.
So . . . The difference between inhaled and exhaled air is:
Inhaled air is dryer and has more oxygen
Exhaled air is wetter and has less oxygen but more Carbon Dioxide.
I hope this helps you with your studies.
Try the links in the MadSci Library for more information on Biochemistry.