(98e) Characterization and Particle Sizing of the Composition of E-Cigarette Aerosol

In recent years, electronic cigarettes, or e-cigarettes, have rapidly gained immense popularity throughout the world and specifically the United States.  Despite the increase in use, little is known about the health effects of these vaporizers, compared to traditional cigarettes.  The e-cigarette uses a wick and heated coil to atomize e-liquid, creating the aerosol inhaled by the user.  E-liquids are composed of propylene glycol, glycerin, usually nicotine, and various flavoring agents.  E-cigarettes were customized in order to simulate a puff on the device by pushing a known volume of air through.  An Automated Puffer Machine (APM) was designed to control power delivered to the coil, puff volume, puff frequency, and puff duration.  An Electrostatic Classifier (EC) and Condensation Particle Counter (CPC) then sampled a diluted puff, analyzing particle size and concentration.  A Poly Urethane Foam (PUF) sampler was used to separate and trap the chemical components of the e-cigarette emission.  The PUF was then placed in a volatile solvent to dissolve the particulate and vapor components, and the solvent was analyzed using gas chromatography with mass spectroscopy.  The PUF sample was used because is closely emulates what a user would normally inhale.

Work has also been done to quantify and describe the aerosol released by electronic cigarettes in order to create profiles of the particles released into the atmosphere. Examples include work to quantify particle size distribution and chemical content of the aerosol in large gas chambers and looking at particle size and distribution with rapid sampling.  Particle size of the aerosol was a bimodal distribution, with main peak averages of 30 nanometers and 80 nanometers.  Research isolated the components of the e-liquid attempting to sort which vaporized component contributed to the collected particle size profile.  Further research attempted to determine the amount of nicotine available within both the vapor and particle components of the aerosol and identify the exact composition of the aerosol created by an e-cigarette when the e-liquid is vaporized.  

This study has found that a variety of e-liquids ranging in nicotine contents and flavors consistently produce a bimodal distribution of aerosol particle sizes.  Furthermore, this study concludes that the proportion of components effects the concentration of particles of the aerosol.