the following parameters decrease with increasing height of stalk position of the bright-tobacco leaf:
1. Filling power and pressure drop (Table 1.),
2. Combustibility and static-burning rate (Table 1).
These two factors and the change in the chemical composition of the leaves result in increased yields of the following smoke constituents with increase in height of stalk position:
1. TPM (Table 1),
2. Nicotine (Table 1.),
3. pH of total smoke (Table 2),
4· Hydrogen cyanide (Table 4),
5· Volatile phenols (Table 5),
6. PAH, as determined with BaA and BaP (Table 6)
The results demonstrate that the higher the leaf on the stalk, the less its filling power and combustibility and the greater the pH, total particulate matter, nicotine, hydrogen cyanide, volatile phenols, and polynuclear aromatic hydrocarbons of the mainstream smoke. Carbon monoxide, acetaldehyde, and acrolein are found in the highest concentration in the smoke formed from leaves in the middle stalk positions. The concentration of CO2 was comparable for the smoke from the leaves of all stalk positions of a given bright tobacco variety.
These chemical·analytical data suggest that the relative potential toxicity and tumorigenicity of the smoke of bright tobacco increase with the ascending stalk position of the leaf.
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