A Single Session of Vaping Can Hurt Your Lungs An updated overview of e cigarette impact on human health Respiratory Research Springer Nature Link 1,2 Propylene Glycol: A Biomarker of Exposure Specific to e Cigarette Consumption Researchers at the University of California, Riverside, found that heating propylene glycol, the main ingredient in most e cigarette liquids, can produce two toxic chemicals, methylglyoxal and acetaldehyde, which damage lung cells. Using