Volatilization and partitioning of residual electronic cigarette vapor to aerosols.

Introduction:
This article examines the impact of electronic cigarette (e-cig) residue on indoor air quality by investigating the evaporation and subsequent partitioning of nicotine and other compounds from e-cig residue. The study aims to determine if chemicals from e-cig residue partition to aerosol particles and the extent of chemical processing that occurs for deposited e-cig vape over time.

Key Points:

* The experiments were conducted using JUUL e-cig vape and a tank-based e-cig, with the former being the primary focus.
* The JUUL experiments involved introducing puffs of vape into a sealed chamber and leaving it undisturbed until the next day, with the chamber being sampled using a high-resolution time-of-flight aerosol mass spectrometer (hR-aMS) and a Picarro G2401 cavity ring-down spectrometer.
* The hR-aMS was used to determine aerosol size and composition, while the Picarro measured gas phase CO, CO2, h2O, and Ch4 concentrations.
* The hR-aMS was operated in V mode with a resolving power of 2000 and calibrations for ionization efficiency were performed using dry 400 nm ammonium nitrate particles.
* Standard relative ionization efficiencies were applied to all other measured ions since none of the major components contain long alkyl functionalities.
* The experimental layout consisted of a pump, atomizer, silica dryer, electrostatic classifier/DMa, valves and filter, residue coated chamber, hR-aMS, and Picarro G2401 cavity ring-down spectrometer.
* The key finding of the study is that chemicals from e-cig residue partition to aerosol particles, indicating a potential long-term impact on indoor air quality and exposure.

Main Message:
The study highlights the importance of understanding indoor electronic cigarette use and unintended routes of exposure. While the chemical processing of vape residue observed in the experiments was less substantial than has been previously presented for residual cigarette smoke, e-cig vape can deposit onto surfaces and act as a long-term source of gas phase nicotine. This nicotine can concentrate on aerosols and increase human exposure, indicating a need for further research and regulation in this area.

Colby hJ, Katz E, avery a, DeCarlo PF. Volatilization and partitioning of residual electronic cigarette vapor to aerosols. In: abstracts, 47th Middle atlantic Regional Meeting of the american Chemical Society, Baltimore, MD, United States, May 30-June 1. american Chemical Society; 2019:MaRM.