Introduction The diversity of e-liquids along with higher powered e-cigarette nicotine delivery devices are increasing. This study evaluated the effect of voltage and e-liquid composition on particle size, nicotine deposition in a human oral-trachea cast model and generation of carbonyls.
Methods Nineteen e-liquids were evaluated for 30 common chemicals by gas chromatography–mass spectrometry (GC-MS). E-cigarette aerosols containing nicotine (1.2%) were generated at 4 and 5 volts for assessment of particle size distribution using Aerodynamic Particle Sizer (APS), Fast Mobility Particle Size (FMPS) and an In-Tox cascade impactor and nicotine deposition by GC-MS. Carbonyl formation in aerosols was assessed by liquid chromatography tandem triple-quad mass spectrometry.
Results Total chemical burden ranged from 0.35 to 14.6 mg/mL with ethyl maltol present in all e-liquids. Increasing voltage was associated with an increase in median size of aerosol particles and the deposition of nicotine in the oral cast. Two e-liquids caused a 2.5-fold to 5-fold increase in nicotine deposition independent of particle size and voltage. Increasing voltage caused an increase in formaldehyde, acetaldehyde and acrolein in the presence and absence of nicotine. Most striking, aerosols from several e-liquids significantly increased levels of acetaldehyde and acrolein compared with unflavoured.
Conclusions Increasing voltage and composition of e-liquid can increase the exposure of the oral pharynx and bronchial airways to carbonyls that can react with DNA to generate adducts, induce oxidative stress, inflammation and cell death. The elevated nicotine and carbonyls readily enter the circulation where they can also cause cardiovascular stress. The growing popularity of higher voltage e-cigarette delivery devices will likely further elevate health risks from chronic exposure to these complex aerosols.
- electronic nicotine delivery devices
Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information. All data is presented in the paper.
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Contributors SB designed the studies with input from CST, YZ and HI. CST, YZ and HI conducted the studies. GW and WWD conducted the analyses. SAB wrote the manuscript, and all authors reviewed manuscript and provided feedback.
Funding This work was supported largely by National Institute of Health grant (R01 DE026013 to SB) and in part by (P30CA11800 to C Willman) from the National Institutes of Health.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.