Explainer: What are e cigarettes? Smoking One Pack of Cigarettes Per Day Causes 150 Extra Mutations in Lung Cells Respiratory Therapy What Does Vaping Do to Your Lungs? Johns Hopkins Medicine New study comes the closest yet to proving that e cigarettes aren't as dangerous as smoking New Harmful Effects of Vaping: Study Finds Lung Inflammation Worse in E Cigarette Users Than Smokers Vaping: How E cigs Work (Infographic) Live Science