Chapter 1 0 
rated up to 10 mg FTC tar, and became insignificant for products rated as 
15 mg FTC tar and higher. It is conceivable that a higher tar (e.g., > 10 mg) 
product exists that incorporates a highly ventilated filter. Such a product 
would be affected by ventilation blockage similar to the way lower tar 
products are affected. 
CONCLUSIONS The FTC procedure for measuring the tar, nicotine, and carbon 
monoxide yields of cigarettes provides an accurate measure of yield for 
cigarettes smoked in the specified manner. It serves the purpose of comparing 
the yields of brands smoked under the same (specified) conditions. The utility 
of the procedure for measuring human exposure is doubtful because it is 
unlikely that all brands are smoked in the same way. This is especially the 
case given the wide variety of products currently available. Results using 
realistic combinations of puff volume, puff frequency, and filter ventilation 
blockage suggest that human smoking conditions can produce from two times 
(nonfilter and standard filter brands) to ten times (low-tar and very-low-tar 
ventilated filter brands) the yields of tar that are measured by the FTC test. 
Nicotine and carbon monoxide yields vary similarly. 
The current FTC test procedure must continue to be used if there is a need 
to compare current products with those of the past. New or additional sets of 
smoking parameters must be adopted if a more accurate measure of human 
exposure is desired. 
QUESTION-AND-ANSWER SESSION 
DR. RICKERT: There was a question I had asked earlier today and I wonder if 
you could answer it. It looks as though you have some information about 
interlaboratory variation, plus within-lab variation, plus variation over time. 
If you measure, for example, a 12-mg cigarette — how different would another 
brand have to be before you would be comfortable in calling it truly different? 
DR. GUERIN: Certainly it would have to be more than 10 percent different. I 
think that it is more like, at that range, about 2 mg different. 
DR. RICKERT: So, you would say that, for example, 10 mg would be 
considered different from one that was 14; but other than that, there would 
be virtually no difference. 
DR. GUERIN: Right. 
REFERENCES 
Bradford, J. A., Harlan, W.R., Hanmer, H.R. Nature of 
cigaret smoke. Technic of experimental smoking. 
Industrial and Engineering Chemistry 28(7): 836-839, 
1936. 
Browne, C.L., Keith, C.H., Allen, R.E. The effect of 
filter ventilation on the yield and composition of 
mainstream and sidestream smokes. Beitrage zur 
Tabakforschung International 10: 81-90, 1980. 
Darrall, K.G. Smoking machine parameters and 
cigarette smoke yields. Science of the Total 
Environment 74: 263-278, 1988. 
DeBardeleben, M.Z., Wickham, J.E., Kuhn, W.F. The 
determination of tar and nicotine in cigarette 
smoke from an historical perspective. Recent 
Advances in Tobacco Science 17: 115-149, 1991. 
Federal Trade Commission. "Tar, Nicotine, and 
Carbon Monoxide of the Smoke of 933 Varieties of 
Domestic Cigarettes." Internal report prepared for 
the National Cancer Institute. Washington, DC: 
Federal Trade Commission, 1994. 
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