UC Irvine

A series of cigarette smoke deposition studies was performed that used hollow models designed to represent the upper airways of adults and children. A major objective of the studies was to look for evidence of the influence of the colligative behavior of concentrated smoke on deposition in the hollow models. Another objective was to identify possible body-size—related factors in cigarette smoke deposition. The concentrated sidestream smoke from 1R3 University of Kentucky unfiltered research cigarettes was drawn through three sizes of airway-like hollow models at flow rates representing resting levels of physical exertion. The models, made of silicone rubber, represented the pharynx, larynx, and first three or four generations of the tracheobronchial airways. The models were scaled in size to represent young adults, 7-year-olds, and 4-year-olds. After smoke deposition, the models were cut into smaller pieces which were ultra sonically agitated in isopropyl alcohol, and the recovered deposits were analyzed spectrophotometrically (at a wavelength of 350 nm). Through the additional analysis of exit filters behind the models, smoke deposition efficiency was quantified. The study was unable to detect any significant effects of body size on the deposition efficiency of smoke. However, significant increases in deposition over those predicted (using accepted deposition models) for submicrometer particles were observed in all casts. The enhanced deposition could be attributed to the colligative behavior of smoke. In fact, the smoke aerosols, which had submicrometer diameter primary particles, deposited in the tracheobronchial trees as if they were between 6 and 7 μm in aerodynamic diameter. © 1994 Elsevier Science Inc.