AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Thermodynamics and Transport Phenomena Governing Electronic Cigarette Aerosol Emissions
Soha Talih, Zainab Balhas, Rola Salman, Rachel El Hage, Nareg Karaoghlanian, Ahmad El Hellani, Mohamad Baassiri, Ezzat Jaroudi, Thomas Eissenberg, Najat A. Saliba, ALAN SHIHADEH, American University of Beirut
Abstract Number: 462 Working Group: Electronic Cigarettes - Particle Generation
Abstract Electronic cigarettes (ECIGs) electrically heat and aerosolize a liquid containing propylene glycol (PG), vegetable glycerin (VG), flavorants, water, and nicotine. Depending on such variables as electrical power, liquid composition, and puff behavior, ECIG users can extract in a few puffs far more or far less nicotine than from a conventional combustible cigarette; in fact, ECIGs probably provide users with a degree of influence over nicotine emissions that is unprecedented for a tobacco product. Because nicotine is an addictive drug, understanding ECIG nicotine emissions is a key regulatory issue. In this study we sought to map the relationships between nicotine emissions and ECIG design features, liquid composition, and operating conditions. To do so, we developed and empirically verified a mathematical model of the unsteady heat and mass transfer phenomena that underlie ECIG operation under a wide range of conditions, and used it to explore the principal processes that govern nicotine and aerosol emission rates (mg/sec). We present data showing that mean nicotine emission rates can range four orders of magnitude for a single device, from 0.1 to 100 ug/s, over a range of realistic use conditions. We also present data and model simulations demonstrating that for a given ECIG device, nicotine emission rates depend on electrical power, nicotine concentration, PG/VG ratio, and puff duration, and, conversely, that emissions are independent of puff velocity and ECIG liquid water content. Using NaCl as a tracer, we also present evidence indicating that bubble burst phenomena represent a measureable but minor source of aerosol emissions during ECIG operation. Finally, we demonstrate that constraining ECIG nicotine emission rates requires regulations that address multiple factors in combination, rather than one factor at a time.