Flavoring Chemicals and Aldehydes in E-Cigarette Emissions

Environ Sci Technol. 2017 Sep 19;51(18):10806-10813. doi: 10.1021/acs.est.7b02205. Epub 2017 Sep 5.


Regulations on e-cigarettes in the U.S. do not provide guidelines on the chemical content of e-cigarette liquids. We evaluated emissions of aldehydes and flavoring chemicals in e-cigarette vapor under typical usage conditions. We selected 24 e-cigarette flavors from the top selling disposable e-cigarette brands. E-cigarettes were connected to a pump drawing air for two second puffs with sixty-second intervals between puffs. The vapor was analyzed for the presence of aldehydes using high-performance liquid chromatography-ultraviolet detector and for the presence of flavoring chemicals with gas chromatography and an electron capture detector. All e-cigarette emissions tested contained at least one aldehyde and/or flavoring chemical on either the FEMA "High Priority Chemicals" or FDA Harmful and Potentially Harmful Constituents lists when sampled at typical usage conditions. Diacetyl, a known respiratory hazard, along with acetoin, were the most prevalent of the flavoring chemicals in e-cigarette vapor, being found in more than 60% of samples. The presence of propionaldehyde, acetaldehyde and formaldehyde were correlated, corroborating previous work suggesting thermal degradation as a pathway for aldehyde generation in e-cigarette vapors. Median formaldehyde concentrations of 626 μg/m3 in e-cigarette vapor exceed the ACGIH maximum concentrations allowable for workers of 370 μg/m3.

MeSH terms

  • Aldehydes / analysis*
  • Electronic Nicotine Delivery Systems*
  • Flavoring Agents / analysis*
  • Formaldehyde / analysis*
  • Nicotine
  • Volatilization


  • Aldehydes
  • Flavoring Agents
  • Formaldehyde
  • Nicotine