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 E liquide got tabac MB The Impact of E Cigarettes on the Lung Providers AmeriHealth Caritas Pennsylvania 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 The Role of ROS in Electronic Cigarette and Heated Tobacco Product Induced Damage