Recovering from the aftermath
An Airman smokes a cigarette, August 20, 2013 at Aviano Air Base, Italy. According to a surgeon general report, within the first month of quitting smoking, carbon dioxide levels in the blood drop to normal, circulation and lung function improve, and cilia (tiny hair-like structures that move mucus out of the lungs) starts to regain normal function in the lungs, increasing the ability to handle mucus, clean the lungs, and reduce the risk of infection. (U.S. Air Force photo/Airman Ryan Conroy)