On Health E cigarettes affect lung biology, even in those who've never smoked vape juice without propylene glycol Vaping is NOT safer than smoking! It's time to debunk the myths surrounding vaping. Many think e cigarettes are a harmless alternative to traditional cigarettes, but research indicates otherwise. Vaping can still Propylene glycol, a component of electronic cigarette liquid, damages epithelial cells in human small airways Respiratory Research Springer Nature Link