Chapter 3 
Figure 7 
BaP and NNK In mainstream smoke of a leading U.S. nonfilter cigarette, 1959-1992 
200 
150 
100 
50 
1955 1960 1965 1970 
1975 
Year 
1980 1985 1990 
0 
1995 
Source: Hoffmann and Hoffmann, 1994a. 
SUMMARY Table 5 indicates the potential roles that filter tips, perforated filter tips, 
cigarette paper, reconstituted tobacco, expanded tobacco, and an increase 
of the share of bright and hurley tobacco in the cigarette blend have in 
affecting the smoke yields of selected toxic and tumorigenic agents. These 
observations have largely been taken into account with respect to the 
manufacture of blended U.S. filter cigarettes, which accounted for 97 percent 
of all cigarettes sold on the U.S. market in 1993. The result is a cigarette 
that delivers smoke with generally lower toxicity and tumorigenicity than 
products that were smoked 40 years ago. However, all the measurements 
on which this evaluation are based were obtained by standardized machine 
smoking with parameters that are not in line with the real practices of men 
and women who smoke the modern, low-yield, filter-tipped cigarettes 
(Russell, 1980; Herning et al., 1981; Kozlowski et al., 1982; Fagerstrom, 1982; 
Haley et al., 1985; Byrd et al., 1994). Is it thus safe to say that the modern 
cigarette is really less harmful? 
31 
NNK (ng) 
