Vaping might be more dangerous than smoking New York Post vape juice without propylene glycol VG PG Ratio Explained: Choosing the Right Vape Juice for Your Kit VSAVI E Liquids Vape Kits Electronic Nicotine Delivery Systems (ENDS) SCIREQ Frontiers Flavorless vs. Flavored Electronic Cigarette Generated Aerosol and E Liquid on the Growth of Common Oral Commensal Streptococci Propylene glycol, a component of electronic cigarette liquid, damages epithelial cells in human small airways Respiratory Research Springer Nature Link