An Artificial Lung Model for Characterizing Deposition of E-cigarette Aerosols in Human Tracheobronchial Airways

HAOXUAN CHEN, Airi Harui, Yu Feng, Michael D. Roth, Yifang Zhu, University of California, Los Angeles

     Abstract Number: 415
     Working Group: Health-Related Aerosols

Abstract
Knowing the characteristics and deposition of inhaled e-cigarette (e-cig) aerosols within the human lung is key for understanding delivery, exposures, and potential toxicity. Current knowledge is limited and often derived from studies that ignore the dynamic aspects of the lung environment. To better understand the physiochemical characteristics and lung deposition of e-cig aerosols, we developed an artificial lung model that consists of a 6L lung exposure chamber. It can be fitted with a trachea alone or with modeled airways down to the 13th generation. The model is attached to a ventilator so that it breathes continuously and can be exposed to intermittent vapes of e-cig aerosol. A heating and humidification system can be independently controlled to approximate the human lung environment.

We studied the size-resolved deposition fraction of e-cig aerosols on the tracheobronchial airways by measuring the size distribution of e-cig aerosols in the lung model with and without the tracheobronchial airways. Our results show a bimodal number-based size distribution of e-cig particles in the lung model. An average of 14% of particles between 40 and 80 nm failed to pass through the terminal bronchial orifices, consistent with airway deposition. Ongoing studies will compare the measured aerosol distribution with those predicted by a computational fluid-particle dynamics model. In addition, we will characterize the e-cig aerosols exhaled by the artificial lung model.

This study provides novel insight as to the physicochemical characteristics of e-cig aerosols inhaled in the lung and valuable information for the exposure analysis of active and passive vaping.