Article Text

other Versions

Download PDFPDF
Might limiting liquid nicotine concentration result in more toxic electronic cigarette aerosols?
  1. Soha Talih1,2,
  2. Rola Salman1,2,
  3. Rachel El-Hage2,3,
  4. Ebrahim Karam1,2,
  5. Nareg Karaoghlanian1,2,
  6. Ahmad El-Hellani2,3,
  7. Najat Saliba2,3,
  8. Thomas Eissenberg2,
  9. Alan Shihadeh1,2
  1. 1Mechanical Engineering Department, American University of Beirut, Beirut, Lebanon
  2. 2Center for the Study of Tobacco Products, Psychology Department, Virginia Commonwealth University, Richmond, Virginia, USA
  3. 3Chemistry Department, Faculty of Arts and Sciences, American University of Beirut, Beirut, Lebanon
  1. Correspondence to Professor Alan Shihadeh, Mechanical Engineering Department, American University of Beirut, Beirut 1107 2020, Lebanon; as20{at}


Some jurisdictions have instituted limits on electronic cigarette (ECIG) liquid nicotine concentration, in an effort to control ECIG nicotine yield, and others are considering following suit. Because ECIG nicotine yield is proportional to the product of liquid nicotine concentration (milligram per millilitre) and device power (watts) regulations that limit liquid nicotine concentration may drive users to adopt higher wattage devices to obtain a desired nicotine yield. In this study we investigated, under various hypothetical regulatory limits on ECIG liquid nicotine concentration, a scenario in which a user of a common ECIG device (SMOK TF-N2) seeks to obtain in 15 puffs the nicotine emissions equivalent to one combustible cigarette (ie, 1.8 mg). We measured total aerosol and carbonyl compound (CC) yields in 15 puffs as a function of power (15–80 W) while all else was held constant. The estimated nicotine concentration needed to achieve combustible cigarette-like nicotine yield at each power level was then computed based on the measured liquid consumption. We found that for a constant nicotine yield of 1.8 mg, reducing the liquid nicotine concentration resulted in greater amount of liquid aerosolised (p<0.01) and greater CC emissions (p<0.05). Thus, if users seek a given nicotine yield, regulatory limits on nicotine concentration may have the unintended consequence of increasing exposure to aerosol and respiratory toxicants. This outcome demonstrates that attempting to control ECIG nicotine yield by regulating one factor at a time may have unintended health effects and highlights the need to consider multiple factors and outcomes simultaneously when designing regulations.

  • electronic nicotine delivery devices
  • nicotine
  • carcinogens

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Twitter @aal_najat

  • Contributors Conception: ST, TE, AS; acquisition and interpretation of data: ST, RS, RE-H, EK, NK, AE-H, NS, TE, AS; drafted the work: ST, AS; revised the work: ST, RS, RE-H, EK, NK, AE-H, NS, TE, AS.

  • Funding This work was supported by the National Institute on Drug Abuse of the National Institutes of Health (grant no U54DA036105) and the Center for Tobacco Products of the US Food and Drug Administration.

  • Disclaimer The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the Food and Drug Administration.

  • Competing interests AS and TE are paid consultants in litigation against the tobacco industry and are named on a patent application for a device that measures the puffing behaviour of ECIG users. TE is also a paid consultant in litigation against the ECIG industry.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.