AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Electronic Cigarette Aerosol Characteristics as a Function of User Preferences
JONATHAN THORNBURG, Seung-Hyun Cho, RTI International
Abstract Number: 165 Working Group: Electronic Cigarettes - Particle Generation
Abstract Use of electronic cigarettes is increasing globally. Despite their growing prevalence, little is known about the physical and chemical properties of e-cigarette emissions inhaled by the user. This research is investigating the role of device settings, e-liquid properties (nicotine content, flavorings) and user topography on a users’ inhalation exposure. These variables differ as a function of user age, gender, and experience. Therefore, the generated aerosol properties and potential toxicity could differ across users.
We produced physiologically relevant e-cigarette aerosol using an e-cigarette smoking machine connected to a simplified, simulated lung. The smoking machine enables tight control over device settings and topography parameters determined from surveys of current users collected as part of this research. The simulated lung mimics the humid environment of the human respiratory system. The size distribution from 10 to 10,000 nanometers and chemical composition of mainstream aerosols are being measured.
The aerosol size distribution produced by two liquids under the control (dry) and test (humid) conditions studied to date are different. The elevated humidity and residence time inside the simulated lung activates the growth of condensation nuclei. The resulting aerosol size distribution inside the simulated lung has a smaller median diameter (184 nm versus 220 nm) but had a broader range (GSD of 3.4 versus 2.8).The aerosol chemical composition changes under humid conditions because the humectants promote absorption of nicotine, flavorings, and preservatives. Nicotine and propylene glycol are the only compounds found in both gas and aerosol phases. The influence of e-cigarette heating element voltage and temperature, puff duration, puff frequency and additional e-liquids on aerosol properties are currently being evaluated.
This research will identify how user demographics and preferences influence the aerosol properties produced by e-cigarettes. Any changes in the aerosol size distribution or chemical composition could influence the design of inhalation toxicology studies.