Hydroxyl Radicals in E-Cigarette Vapor and E-Vapor Oxidative Potentials under Different Vaping Patterns

Yeongkwon Son, Vladimir Mishin, Jeffrey D. Laskin, Gediminas Mainelis, Olivia A. Wackowski, Cristine Delnevo, Stephan Schwander, Andrey Khlystov, Vera Samburova, Qingyu Meng

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Available studies, while limited in number, suggest that e-cigarette vaping induces oxidative stress, with one potential mechanism being the direct formation of reactive oxygen species (ROS) in e-vapor. In the present studies, we measured the formation of hydroxyl radical (·OH), the most destructive ROS, in e-vapor under a range of vaping patterns (i.e., power settings, solvent concentrations, flavorings). Study results show that increased power output and puff volume correspond with the formation of significantly higher amounts of ·OH in e-vapor because of elevated coil temperature and oxygen supply. Vegetable glycerin (VG) e-liquids generated higher ·OH levels than propylene glycol (PG) e-liquids, as did flavored e-liquids relative to nonflavored e-liquids. E-vapor in combination with ascorbic acid, which is an abundant biological molecule in human epithelial lining fluid, can also induce ·OH formation. The dose of radical per puff associated with e-cigarette vaping was 10-1000 times lower than the reported dose generated by cigarette smoking. However, the daily average ·OH dose can be comparable to that from cigarette smoking depending on vaping patterns. Overall, e-cigarette users who use VG-based flavored e-cigarettes at higher power output settings may be at increased risk for ·OH exposures and related health consequences such as asthma and chronic obstructive pulmonary disease.

Original languageEnglish (US)
Pages (from-to)1087-1095
Number of pages9
JournalChemical Research in Toxicology
Issue number6
StatePublished - Jun 17 2019

All Science Journal Classification (ASJC) codes

  • Toxicology


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