AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
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Aldehyde Emissions from Electronic Cigarettes: Relation to Atomizer Age, Product Manufacturing Variability, and Intra-puff Particle Generation Intermittency
Mohamad Baassiri, Rola Salman, Soha Talih, Nareg Karaoghlanian, ALAN SHIHADEH, American University of Beirut
Abstract Number: 463 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. They typically employ an atomizer consisting of an electrical heating filament wrapped around a fibrous wick which serves to replenish liquid as it evaporates. Volatile aldehyde (VA) species, including the human carcinogen formaldehyde, are commonly found in ECIG aerosols, and have been implicated in respiratory diseases in cigarette smokers. VAs are known thermal degradation products of PG and VG. Literature reports of VA yields from electronic cigarettes indicate wide variability in emission rates even when measurement conditions and devices are nominally identical, sometimes confounding study findings. In this study we sought to identify potential sources of variability in VA yields within a given product. In particular, using three nominally identical devices, we investigated effects on VA emissions of atomizer age (zero to more than 1200 puffs) and device variability under various randomly ordered use conditions (4 or 11 W, 4 different PG/VG ratio solutions). In addition, instantaneous particle emission rates were measured during repeated sessions of 15-puffs using a fast particle mobility spectrometer (TSI EEPS). Simultaneously, instantaneous heating filament temperatures were measured. We found large differences in VA emissions across devices, and across power levels. ECIG age (cumulative number of puffs taken prior to measurement) and PG/VG ratio had no effect on VA yields. Greater variability in instantaneous intra-puff particle emission rates and atomizer temperatures were associated with greater aldehyde yields, suggesting that high-emitting ECIG units may be more prone to intermittent starvation of liquid in the heating element of the atomizer during a puff (e.g. due to poor contact between heating filament and wick). This finding would suggest that better quality control in the manufacturing of the wick-heater assembly may reduce human exposure to unwanted ECIG toxicants.