AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Analysis of Aerosol Size Distribution Measurement of Electronic Cigarettes Emissions
VLADIMIR MIKHEEV, Marielle Brinkman, Alexander Ivanov, Sydney Gordon, Pamela I. Clark, Battelle Public Health Center for Tobacco Research
Abstract Number: 179 Working Group: Electronic Cigarettes - Particle Generation
Abstract Electronic cigarette use is increasing worldwide but our understanding of their health risk relative to combustible tobacco products has not kept pace with this tobacco product’s popularity. There is lack of data describing the aerosol size distribution generated by e-cigarettes. This is an important data gap, as aerosol size is a critical parameter that defines the delivery site and deposition efficiency in the human respiratory system, and thus governs the systemic uptake of inhaled compounds. Due to the abundance of relatively volatile compounds (i.e., propylene glycol and water), the e-cigarette aerosol/vapor mixture is a highly dynamic system that, under different conditions, could result in either rapid particle growth or evaporation. For example, at high dilution, e-cigarette aerosol quickly evaporates and the nano-size fraction significantly increases. The chemical content of e-liquid (propylene glycol, glycerol, water, nicotine, and flavorings), heating power, and the puffing flow rate, also have an effect on the particle size distribution.
In order to obtain an undistorted picture of aerosol size distribution, minimal sample dilution is required, along with quick delivery and real-time measurements that cover wide range of particle size (from nanometers to microns) and high concentration (up to 8-9 orders of magnitude). Analysis of the available techniques shows that none of the single aerosol measurement instruments could satisfy all these requirements. Combination of differential mobility with optical scattering or/and impactor techniques seems to be most applicable to measure e-cigarette aerosol.
Our differential mobility measurements taken at low sample dilution typically show a bi-modal particle size distribution which includes high concentration of nanoparticles. This size distribution is different from that reported for combustible tobacco smoke. Nanoparticles that are more active biologically and therefore could possess higher health risk requires investigation of their chemical content. Size-segregated chemical analyses of e-cigarette aerosol emissions will be discussed.