Harmful and potentially harmful constituents (HPHCs), such as aldehydes, can form in electronic nicotine delivery system (ENDS) aerosols due to overheating during aerosol production. Overheating may result from imprecise temperature control of the heating element used to aerosolize ENDS e-liquids. JUUL2 is a next-generation ENDS device engineered with active temperature control that maintains a consistent temperature during e-liquid heating and aerosolization, minimizing formation of low-level thermally-generated HPHCs. This study focuses on the formation of HPHCs as a function of temperature.

Selected HPHCs formed in the aerosol produced by non-commercial JUUL2 devices were studied as a function of vaporization temperature. A range of temperature setpoints (247 °C, 271 °C, 296 °C, and 321 °C) were created by altering the device firmware. An e-liquid formulation consisting of a 50:50 PG:VG blend with 4% nicotine with equimolar benzoic acid was used in these studies. The samples were analysed for PG, VG, nicotine via GC-FID, carbonyls by LC-MS, and glycidol by GC-MS.

The results demonstrated a three-fold increase in Total Aerosol Mass (TAM) as the temperature increased from 247°C to 296 °C, then remained constant at 9 mg/puff when the temperature was further increased to 321 °C. Similar trends were observed for PG, VG, and nicotine levels. Carbonyls and glycidol exhibited a four-fold and eight-fold increase, respectively, as the temperature increased. The data exhibited low variance (<5%), indicating consistent device performance throughout the study. The study suggests that increasing the temperature set-point in the device beyond the level typically found in commercial JUUL2 devices had minimal impact on the per-puff delivery of nicotine. Additionally, the levels of HPHCs detected in the aerosol were lower than those typically found in combustion during the use of conventional cigarettes.