Characterizing the Transient Emission of Particles and Gases From Single Puff of Electronic Cigarette Smoke

KAPIAMBA KASHALA FABRICE, Yue-Wern Huang, Yang Wang, University of Miami

     Abstract Number: 66
     Working Group: Health-Related Aerosols

Abstract
The prevalence of electronic cigarettes (ECs) has escalated concerns about potential health risks associated with the emitted aerosols and gas species. Herein, we utilized high-time-resolution characterization systems to study the transient emission of aerosols and gases emitted from a single puff of EC smoke. First, we used the Differential Mobility Spectrometer (DMS500) to capture the transient particle size distribution (PSD) of EC aerosols from various brands (JUUL, VOOPOO, VUSE) under controlled conditions, including puff duration, EC power, and e-liquid composition. Significant variations in PSD were observed under different EC operating conditions, predominantly in the size range from 5 nm to 800 nm and a total number concentration in the range of 108 to 1010 particles/cm3. Smaller particles, which are more likely to deposit in the deeper respiratory system were generated particularly in shorter puff durations (2 s). Using the PSDs, we estimated the deposited dose of aerosols in different regions of the respiratory system using the ICRP deposition model. Second, we measured CO2, NOx, CO, and unburned hydrocarbons post-puff and compared these levels against the Occupational Safety and Health Administration (OSHA) Permissible Exposure Limits (PELs). We found that while CO2 and NOx levels remained within safe limits (with peaks values 880 ± 102 ppm and 3.9 ± 0.7 ppm, respectively), CO levels (with a peak value of 905 ± 50 ppm) exceeded OSHA thresholds by 5 folds when compared to the adjusted 8-hour workday average PEL, highlighting potential safety concerns. The findings advocate for further research to understand the intricate dynamics of EC aerosol generation and evolution. Overall, this study demonstrated the complexity of EC emissions and the necessity for standardized measurement methods to accurately assess their health implications.