Section IV 
Table 7 
Effects of blocking the ventilation holes on the yields of a popular, low-yield cigarette^ 
Characteristics 
Unblocked 
Holes 
Half-Blocked 
Holes 
Fully Blocked 
Holes 
Constituents 
Nicotine (mg) 
0.45 
0.73 ± .06 
0.98 ± .06® 
Tar (mg) 
4.40 
7.03 ± .04 
12.60 ±.20® 
Carbon Monoxide (mg) 
4.50 
7.80 ± .24 
17.70 ±.40® 
Puffs 
11.10 
10.50 ± .20 
9.20 ± .40® 
® Half-blocked vs. fully blocked comparison (\.-test, 2-tailed) p < .01. Values are means ± standard deviations. 
Government figures for the June-July 1979 assay were used as the unblocked control; variances were not reported, 
but those found in similar analyses imply that all within-row comparisons would be statistically significant. All 
analyses in the table were performed by the same laboratory employing the same techniques. 
Source: Kozlowski et al., 1980b. 
Bridges and colleagues (1990) studied 170 male smokers to determine 
the influence on yield of smoking topography (i.e., total smoking time per 
cigarette, number of puffs, interpuff interval, puff duration, volume per puff, 
total duration per cigarette, total volume per cigarette, flow rate). The 
smokers were divided into six groups according to stated nicotine yields 
of their cigarettes. The first four groups were most similar in age, smoking 
history, and alcohol and coffee consumption. There were significant 
negative correlations between nicotine yield and mean puff volume, total 
duration and volume, and flow rate. That is, as nicotine yield decreased, 
mean puff volume, total duration and volume, and flow rate increased 
significantly. These statistical relationships are shown in Figure 9. Multiple 
regression analysis showed that nicotine yield, alone or in combination with 
other factors, is a significant predictor of number of puffs or total puff 
volume per cigarette. 
Figure 9 is of special interest because it represents smoking topography 
changes in a subpopulation for which nicotine yield was held constant 
to control for the possible confounding effects of nicotine on smoking 
behavior. Cumulative puff volume for a cigarette is significantly correlated 
with plasma nicotine, an indication that increased inhalation results in 
increased absorption. For the same group, the interpuff interval was 
negatively correlated with plasma nicotine levels (i.e., when time between 
puffs went down, plasma nicotine level went up). 
According to Bridges and colleagues (1990, p. 31) 
Smokers smoking the lowest yield cigarettes (Group 1) had 
significantly higher total puff volume per cigarette than did the 
other groups, and significantly higher mean puff volume and 
flow rate . . . than Groups 3 and 4. Smokers of lower yield 
267 
