Chapter 1 1 
(Zacny et al., 1987), three parameters were systematically manipulated: 
puff volume (15, 30, 45, and 60 mL), inhalation volume (0, 20, 40, and 
60 percent of vital capacity, respectively), and breath-hold duration (0, 4, 8, 
and 16 seconds, respectively). As puff volume increased, the amount of 
nicotine and CO absorbed from a cigarette increased in a systematic fashion. 
However, varying the amount of air mixed with the smoke as it was inhaled 
(inhalation volume) did not affect nicotine or CO boost; exposure was as 
great with a shallow inhalation as with a deep inhalation. Breath-hold 
duration increased CO boost but had no effect on nicotine boost. In 
summary, the smoking topography parameters that appear to have the larger 
effect on smoke exposure are vent blocking of low-yield cigarettes and the 
number and size of puffs taken from any cigarette. 
ARE HUMAN 
SMOKING 
PATTERNS 
DYNAMIC OR 
STATIC? 
Much literature indicates that human smoking patterns are dynamic 
and different from the static FTC smoking method. Puffing parameters 
change during the course of smoking a single cigarette. Initially, 
smokers take larger and longer puffs from the cigarette, but as they 
smoke down the rod, the puffs get shorter and smaller. Interpuff 
intervals are shortest at the beginning of the cigarette and longest near the 
end of the cigarette. Smokers engage in activities that can have an influence 
on smoking topography. Hatsukami and colleagues (1990) developed a 
portable device that measures number of puffs, interpuff intervals, and puff 
durations and assessed these parameters in a smoker's natural environment. 
They found that variables, including mood of the smokers (relaxed vs. 
stressed) and activities of the smoker (working vs. socializing), influenced 
smoking topographies. Psychoactive drugs other than tobacco (e.g., 
stimulants, alcohol, opioids) also can influence smoking topographies. 
Several investigators have noted changes in smoking topography as a 
function of alcohol. Keenan and associates (1990) studied smoking 
topography in alcoholic and nonalcoholic smokers: Alcoholic smokers 
took more puffs from their cigarettes than did the nonalcoholic smokers, 
indicating more intensive smoking and suggesting higher exposure levels 
per cigarette. 
Two other examples demonstrate that smoking is a dynamic process. 
In the first example, Fant and associates (1995) studied smoking deprivation. 
The number of cigarettes that subjects were permitted to smoke varied from 
0 to 11 during a 6-hour period. The number of puffs taken was directly 
related to the interval between cigarettes and inversely related to the number 
of cigarettes smoked. In the second example, the authors reviewed studies 
over the past 15 years that examined smoking topography as a function of 
cigarette yield. We included only those studies that assessed the smoking of 
commercially available, as opposed to research, cigarettes. We also arbitrarily 
defined high-yield cigarettes as having nonventilated filters and an FTC 
nicotine yield of 0.8 mg or more and low-yield cigarettes as having ventilated 
filters and an FTC nicotine )deld of 0.6 mg or less. Table 1 summarizes the 
seven studies that fit these criteria. A consistent finding in these studies is 
that puff volume and puff number are both larger when low-yield compared 
with high-yield cigarettes were smoked. Overall, it is clear that smoking 
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