CIGARETTE-SMOKE DEPOSITION IN THE TRACHEOBRONCHIAL TREE - EVIDENCE FOR COLLIGATIVE EFFECTS

A series of cigarette smoke deposition studies was performed that used hollow models designed to represent the upper airways of adults and c hildren. A major objective of the studies was to look for evidence of the influence of the colligative behavior of concentrated smoke on dep osition in the hollow models. Another objective was to identify possib le body-size-related factors in cigarette smoke deposition. The concen trated sidestream smoke from 1R3 University of Kentucky unfiltered res earch cigarettes was drawn through three sizes of airway-like hollow m odels 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. T he models were scaled in size to represent young adults, 7-year-olds, and 4-year-olds. After smoke deposition, the models were,cut into smal ler pieces which were ultrasonically agitated in isopropyl alcohol, an d the recovered deposits were analyzed spectrophotometrically (at a wa velength of 350 nm). Through the additional analysis of exit filters b ehind the models, smoke deposition efficiency was quantified. The stud y was unable to detect any significant effects of body size on the dep osition efficiency of smoke. However, significant increases in deposit ion over those predicted (using accepted deposition models) for submic rometer 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, d eposited in the tracheobronchial trees as if they were between 6 and 7 mum in aerodynamic diameter.