Highly reactive free radicals in electronic cigarette aerosols

Chem Res Toxicol. 2015 Sep 21;28(9):1675-7. doi: 10.1021/acs.chemrestox.5b00220. Epub 2015 Aug 7.


Electronic cigarette (EC) usage has increased exponentially, but limited data are available on its potential harmful effects. We tested for the presence of reactive, short-lived free radicals in EC aerosols by electron paramagnetic resonance spectroscopy (EPR) using the spin-trap phenyl-N-tert-butylnitrone (PBN). Radicals were detected in aerosols from all ECs and eliquids tested (2.5 × 10(13) to 10.3 × 10(13) radicals per puff at 3.3 V) and from eliquid solvents propylene glycol and glycerol and from "dry puffing". These results demonstrate, for the first time, the production of highly oxidizing free radicals from ECs which may present a potential toxicological risk to EC users.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aerosols / chemistry*
  • Electron Spin Resonance Spectroscopy
  • Electronic Nicotine Delivery Systems*
  • Free Radicals / analysis*


  • Aerosols
  • Free Radicals