Smoking and Tobacco Control Monograph No. 7 
Puff frequency (Table 4) and filter ventilation (Table 5) were found to 
have the greatest effect on yields. Decreasing the puff interval from 60 to 
40 seconds increased the deliveries of tar, nicotine, and carbon monoxide by 
20 to 50 percent on a per-cigarette basis. Using a puff interval of 30 seconds 
increased deliveries by 40 to 90 percent. Blocking the ventilation system of 
ventilated filter cigarettes has similar effects for products using a low degree 
of ventilation and a much greater effect for highly ventilated products. This 
is particularly important for very-low-delivery (e.g., si mg tar) products 
because they typically use highly ventilated filters. Darrall (1988) reported 
that complete blockage of the filter ventilation of a nominally 4.0-mg tar 
product resulted in a tar yield of 10 mg (Table 5); nicotine increased from 
0.5 to 0.8 mg, and carbon monoxide rose from 4 to 13 mg. Lower yield 
products employ more highly ventilated filters than in Darrall's (1988) 
example, and the influence of filter blockage would be expected to be 
greater for such products. 
The importance of filter ventilation to FTC testing is illustrated by the 
results summarized in Figure 1. Nonfilter, filter (F), and ventilated filter (VF) 
commercial cigarettes were smoked (see next section, "Influence of Human 
Smoking Practices") under standard FTC conditions and again under standard 
conditions but with 23 mm of the butt end taped (FTC+). All cigarettes. 
Table 4 
Influence of puff frequency on machine yields 
Percentage Increase Over Standard Federal Trade Commission Method 
40 Seconds 30 Seconds 
Carbon Carbon 
Puffs 
Tar 
Nicotine 
Monoxide 
Puffs 
Tar 
Nicotine 
Monoxide 
Regular (M-H) 
28 
31 
29 
26 
62 
60 
49 
38 
Regular (M-H) 
24 
33 
32 
23 
52 
69 
54 
42 
KS-UM-V (L) 
47 
55 
24 
43 
90 
154 
47 
67 
KS-EM-V (L) 
27 
31 
32 
32 
52 
94 
60 
64 
KS-EM-V (L) 
30 
21 
19 
27 
69 
84 
48 
79 
KS (L) 
38 
19 
19 
24 
76 
54 
38 
43 
KS-NV (L-M) 
31 
44 
35 
33 
57 
62 
61 
39 
KS-NV (M) 
26 
26 
16 
16 
60 
60 
32 
32 
IS-NV (L-M) 
38 
46 
42 
39 
70 
62 
58 
46 
Key: M-H = middle to high tar (23 to 28 mg): KS = king size; UM = ultramild (<4 mg tar); V = ventilated; L = low tar (0 to 
10 mg): EM = extra mild (4 to 7 mg tar); NV = nonventilated; L-M = low to middle tar (11 to 16 mg): M = middle tar 
(17 to 22 mg); IS = international size. 
Source: Darrall, 1988. 
140 
