Jan. 27, 2008 — A new study finds that the development of bullous lung disease occurs in marijuana smokers approximately 20 years earlier than tobacco smokers.
A condition often caused by exposure to toxic chemicals or long-term exposure to tobacco smoke, bullous lung disease (also known as bullae) is a condition where air trapped in the lungs causes obstruction to breathing and eventual destruction of the lungs.

http://www.sciencedaily.com/releases/2008/01/080123104017.htm