Smoking and Tobacco Control Monograph No. 7 
Figure 2 
Relationship between carbon monoxide (CO) concentration of alveolar air 
in smokers and CO yield of cigarettes smoked 
90 
80 
E 
70 
Q. 
Q. 
60 
O 
u 
w 
50 
< 
nj 
40 
o 
(V 
> 
30 
< 
20 
10 
5 10 15 20 25 
CO Yield (mg) 
Source: Ebert etai, 1983. 
Ventilation and burning characteristics are the primary determinants of 
machine-measured yields, and these characteristics can be controlled by 
smokers. Benowitz and colleagues acknowledged that blood cotinine is not 
a "perfect marker," but a full range of cigarettes was included in the study 
and there is no reason to suspect that brand is related to nicotine and 
cotinine metabolism. 
Russell and colleagues (1986) examined blood nicotine, cotinine, and 
carboxyhemoglobin (COHb) levels among 392 smokers whose regular brands 
varied from low tar to middle tar. Tar levels were estimated from blood 
nicotine levels and cigarette tar yields. The authors reported 
Smokers of LT [low-tarj cigarettes had a lower intake of tar, 
nicotine, and CO than the smokers of higher yielding brands. On 
average, their estimated intake of tar was about 25 percent lower, 
their intake of nicotine was about 15 percent lower (17 percent 
and 12 percent, as measured by blood nicotine and cotinine, 
respectively), and their intake of CO was about 10 percent lower. 
I'hese differences are substantially less than the reductions in the 
standard machine-smoked yields of their cigarettes (47 percent, 
39 percent, and 34 percent for tar, nicotine, and CO yields, 
respectively), and this indicates the extent to which the LT 
smokers were smoking and inhaling more intensively, {)resumably 
to corn[)ensate for the lower yields. However, it is clear that 
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