Lung Deposition Analyses of Inhaled Toxic Aerosols in Conventional and Less Harmful Cigarette Smoke: A Review

Abstract

Inhaled toxic aerosols of conventional cigarette smoke may impact not only the health of smokers, but also those exposed to second-stream smoke, especially children. Thus, less harmful cigarettes (LHCs), also called potential reduced exposure products (PREPs), or modified risk tobacco products (MRTP) have been designed by tobacco manufacturers to focus on the reduction of the concentration of carcinogenic components and toxicants in tobacco. However, some studies have pointed out that the new cigarette products may be actually more harmful than the conventional ones due to variations in puffing or post-puffing behavior, different physical and chemical characteristics of inhaled toxic aerosols, and longer exposure conditions. In order to understand the toxicological impact of tobacco smoke, it is essential for scientists, engineers and manufacturers to develop experiments, clinical investigations, and predictive numerical models for tracking the intake and deposition of toxicants of both LHCs and conventional cigarettes. Furthermore, to link inhaled toxicants to lung and other diseases, it is necessary to determine the physical mechanisms and parameters that have significant impacts on droplet/vapor transport and deposition. Complex mechanisms include droplet coagulation, hygroscopic growth, condensation and evaporation, vapor formation and changes in composition. Of interest are also different puffing behavior, smoke inlet conditions, subject geometries, and mass transfer of deposited material into systemic regions. This review article is intended to serve as an overview of contributions mainly published between 2009 and 2013, focusing on the potential health risks of toxicants in cigarette smoke, progress made in different approaches of impact analyses for inhaled toxic aerosols, as well as challenges and future directions.

Electronic Cigarettes

“…58,105,107 To date, there is insufficient evidence to support the notion that exposure to exhaled aerosol has a deleterious impact on bystanders. 26 Some studies have found very low concentrations of air pollutants across different types, liquids, puff durations, and nicotine concentrations.…”

Will chronic e-cigarette use cause lung disease?

“…Parameters of E-Cig emission, such as aerosol size, mass output, and chemical composition, vary by device and e-liquid types and are predicted to impact the user's exposure to the E-Cig aerosol. For example, aerosol size strongly affects how much of an aerosol is delivered to different regions of the lung and how much is retained in the oral cavity (16,82).…”

Multiscale CT-Based Computational Modeling of Alveolar Gas Exchange during Artificial Lung Ventilation, Cluster (Biot) and Periodic (Cheyne-Stokes) Breathings and Bronchial Asthma Attack

“…Currently, in silico studies addressed to respiratory lung modeling have been covering detailed patient-specific 3D lung reconstruction [13,14], nasopharynx-trachea ventilation features [6,7,15], 3D-1D coupling of upper and middle airway segments, and FSI simulations [16]. The lumped models operate with lung mechanics in terms of tidal volume and pressure with lower details [17,18].…”