Physiochemical Properties of Thirdhand Smoke Generated from Electronic Nicotine Delivery Systems

KAPIAMBA KASHALA FABRICE, Gabriel Georgakopoulos, Weixing Hao, Yue-Wern Huang, Yang Wang, University of Miami

     Abstract Number: 154
     Working Group: Indoor Aerosols

Abstract
We examined the physiochemical properties of thirdhand smoke (THS) generated from Electronic Nicotine Delivery Systems (ENDS). ENDS have gained significant popularity and raised public health concerns due to their potential adverse effects. The study aimed to characterize ENDS THS and understand how different material surfaces and environmental conditions influence its formation. Various common materials, including fabrics, stainless steel, and plastics, were exposed to simulated secondhand ENDS aerosols in a controlled chamber. After a 24-hour exposure period, the chamber was subjected to changes in environmental conditions, including changes in temperature (20 to 40 ºC), relative humidity (10 to 90%), and vibration (1 to 50 Hz). The emitted aerosols were analyzed for size distributions using particle sizers and chemical composition using inductively coupled plasma mass spectrometry and gas chromatography-mass spectrometry. The results revealed distinct aerosol size distributions and chemical compositions of ENDS THS depending on the type of contaminated surface. The size distribution analysis showed a bimodal distribution, with one fine-mode around 200 nm and another coarse-mode at 1 µm, while the number concentration ranged from 103 to 106 cm-3. Environmental factors such as temperature, humidity, and vibration were found to influence ENDS THS emission concentration and composition. In addition, we also observed trace metals associated with ENDS emission (Kapiamba et al., 2022), including Cr, Ni, Pd, Zn, and low concentrations of VOCs and carbonyls. These findings highlight the importance of assessing the health and environmental impacts of ENDS THS.

Kapiamba et al., Chem. Res. Toxicol., 35(6): 954-962.