The nicotine yield of a cigarette is determined by the nicotine content of the tobacco; the static burn rate or amount of tobacco consumed during smoking; the pressure drop of the tobacco column; porosity of the wrapper and or ventilation at the filter; the pressure drop of the filter, the filter material, the surface area of the filter material; and the affinity of the filter material for nicotine particularly as a function of smoke pH. Through the combination of these variables, plant genetics, and commercial processes to remove nicotine from tobacco, it is possible to manipulate the yield of nicotine from about.1 mg to 4 mg per cigarette.
The primary control of nicotine delivery (the amount received by the smoker), is in the design and careful, sophisticated manufacture of the cigarette to ensure that the smoker obtains the precise amount of nicotine intended by the manufacturer.
The industry's control and manipulation of nicotine in the production of cigarettes begins before the cured tobacco leaf reaches the manufacturing plant. The characteristics of leaf tobacco, including nicotine content, are established by the genetic makeup of the plant, developed during growing, and fixed by post-harvest handling. Like other raw agricultural commodities, the physical and chemical properties of tobacco, including nicotine, can vary widely, depending on genetic differences, growing season conditions, and soil type. Modern types of cultivated tobacco (Nicotiana tabacum L) have been selected for a relatively high level of nicotine. Five major types of tobacco make up nearly all tobacco products marketed: Burley, flue-cured, Maryland, the Dark tobaccos, and Oriental.
A class action by nine people representing a half-million sick smokers or their survivors in the US State of Florida resulted in a landmark finding (July 1999) which held America's five largest tobacco companies liable for making a defective product. The jury found that the industry had "engaged in extreme and outrageous conduct... with the intent to inflict severe emotional distress". The Florida ruling has delivered such a broad condemnation of the tobacco industry that a flurry of similar class-action claims is considered inevitable.
At least one major US cigarette manufacturer, Brown and Williamson, has developed and marketed a tobacco so high in nicotine that it exceeded the limits imposed for U.S.-grown tobacco under the Minimum Standards Program. These limits cannot be exceeded without significant risk of losing government- administered price support. However, foreign-grown tobaccos are not subject to these specifications and are not subject to testing for nicotine content upon entry into the United States. This high-nicotine tobacco was therefore grown in South America.
The development of enhanced nicotine tobacco (Y-1) dates back to at least the mid-1970's. In 1977, James F. Chaplin, who was affiliated with both USDA and North Carolina State University, indicated that tobacco could be bred to increase nicotine levels, by crossbreeding commercial varieties of tobacco with Nicotiana rustica. N. rustica is a wild tobacco variety that is very high in nicotine, but is not used in manufacturing cigarettes because of its harshness.
The tobacco industry engages in a number of agronomic practices that increase nicotine levels in tobacco. Heavy application of nitrogen fertilizers, early topping, and tight "sucker control" (i.e., bud growth at the junction of stalk and leaves) have all acted in concert to push nicotine levels upward.
Smokeless tobacco manufacturers both manipulate the amount of nicotine delivered by their products and promote the graduation of smokeless tobacco consumers from the lowest to the highest nicotine products, demonstrating an intention to facilitate nicotine dependence.