Effects of user puff topography, device voltage, and liquid nicotine concentration on electronic cigarette nicotine yield: measurements and model predictions

Abstract

Introduction: Some electronic cigarette (ECIG) users attain tobacco cigarette-like plasma nicotine concentrations while others do not. Understanding the factors that influence ECIG aerosol nicotine delivery is relevant to regulation, including product labeling and abuse liability. These factors may include user puff topography, ECIG liquid composition, and ECIG design features. This study addresses how these factors can influence ECIG nicotine yield.

Methods: Aerosols were machine generated with 1 type of ECIG cartridge (V4L CoolCart) using 5 distinct puff profiles representing a tobacco cigarette smoker (2-s puff duration, 33-ml/s puff velocity), a slow average ECIG user (4 s, 17 ml/s), a fast average user (4 s, 33 ml/s), a slow extreme user (8 s, 17 ml/s), and a fast extreme user (8 s, 33 ml/s). Output voltage (3.3-5.2 V or 3.0-7.5 W) and e-liquid nicotine concentration (18-36 mg/ml labeled concentration) were varied. A theoretical model was also developed to simulate the ECIG aerosol production process and to provide insight into the empirical observations.

Results: Nicotine yields from 15 puffs varied by more than 50-fold across conditions. Experienced ECIG user profiles (longer puffs) resulted in higher nicotine yields relative to the tobacco smoker (shorter puffs). Puff velocity had no effect on nicotine yield. Higher nicotine concentration and higher voltages resulted in higher nicotine yields. These results were predicted well by the theoretical model (R (2) = 0.99).

Conclusions: Depending on puff conditions and product features, 15 puffs from an ECIG can provide far less or far more nicotine than a single tobacco cigarette. ECIG emissions can be predicted using physical principles, with knowledge of puff topography and a few ECIG device design parameters.

Figure 1.

Effect of user profile and device voltage on aerosol nicotine yield from 15 puffs. The profiles represent a typical tobacco cigarette smoker (2-s puff duration, 33-ml/s puff velocity) and experienced ECIG users with 4-s (average) or 8-s (extreme) puff durations and slow (17ml/s) or fast (33 ml/s) puff velocities. Error bars indicate 95% confidence intervals. ECIG = electronic cigarette.

Figure 2.

Electronic cigarette (ECIG) temperature (T), nicotine flux, nicotine saturation pressure (P _sat), and mass transfer coefficient (h) during and between puffs, as predicted by the mathematical model (condition shown for two 8-s puffs). Panel a illustrates the transient nature of the temperature during a puff. Panel b illustrates the effect of puff velocity on the computed variables.