American Association for Aerosol Research - Abstract Submission

AAAR 39th Annual Conference
October 18 - October 22, 2021

Virtual Conference

Abstract View


Component Specific Evaporation of Filter Collected E-Cigarette Particulate Matter under Wet and Dry Conditions

KAITLYN SUSKI, Brad Ingebrethsen, Nagaraja Rao, Huan Wang, JUUL Labs

     Abstract Number: 693
     Working Group: Health-Related Aerosols

Abstract
Once e-cigarette aerosol exits the generation device, the aerosol undergoes dynamic changes. The particles, which are typically composed of vegetable glycerin (VG), propylene glycol (PG), nicotine, flavor components, and water, can take up or lose water and volatile components in response to changes in the aerosol dilution state, temperature, and relative humidity. Many online aerosol measurement techniques require dilution or the use of aerodynamic lenses under vacuum, which result in evaporation of volatile and semi-volatile components. The chemical composition and size of the particles can be affected by these measurement artifacts, making the study of e-cigarette aerosol challenging. To minimize instrumentation artifacts, e-cigarette aerosol was collected on filters and analyzed using offline gas and liquid chromatography techniques. To simulate component evaporation during aging, the collected material was flushed with air for different lengths of time (up to 1 hour). Flushing was done at 40 °C with wet (RH ≈ 99%) and dry (RH < 5%) air to simulate particle water equilibration and investigate the effect of water on the evaporation kinetics.

This work shows that under dry conditions, PG is almost completely evaporated from the deposited material over the course of the experiment, while VG is mostly retained. Under wet conditions the deposited material takes up water rapidly, which results in an initial spike in evaporation of PG and nicotine (higher than the dry case). Once water uptake slows, PG and nicotine evaporation are reduced compared to the dry case due to dilution of the deposited mass with water. This experimental approach meaningfully simulates the many changes that can occur to e-cigarette aerosol particles during aging and dilution for 2 limiting cases (RH≈ 99% and RH < 5%).