Cigarette smoking evokes major changes in the biology of the airway epithelium, the cell population that takes the brunt of the stress of cigarette smoke and the cell population central to the pathogenesis of chronic obstructive pulmonary disease (COPD) and lung cancer. The focus of this study is to identify the differences that two popular alternative nicotine delivery strategies, shisha and electronic cigarettes, have on the airway epithelium compared to cigarette smoking. We hypothesize that both alternative nicotine delivery strategies disorder airway epithelial biology, but in different ways than does cigarette smoking.