The Formation of Benzo[a]pyrene and Benzo[e]pyrene during the Heating of Tobacco in Correlation to Temperature and Flow Rate in Nitrogen and Air Atmospheres / Die Bildung von Benzo[a]pyren und Benzo[e]pyren beim Erhitzen von Tabak in Abhängigkeit von Temperatur und Strömungsgeschwindigkeit in Luft- und Stickstoffatmosphäre

The authors investigated the dependence upon temperature of the formation of benzo[a]pyrene and benzo[e]pyrene from tobacco pyrolyzed in a thermostatic oven in atmospheres of nitrogen or air. The heating of tobacco to temperatures between 400° and 1000°C was found to result in a marked increase of the benzopyrene yield in the volatile parts. In this temperature range the quantity of benzo[a]pyrene formed from 100 g of tobacco augments from 4.4 µg to 18 350.0 µg (N₂). At comparable temperatures measured in the combustion material by a thermocouple, the amounts of benzopyrenes formed respectively in nitrogen and air atmospheres were almost identical. With the introduction of air into the system the combustion enthalpy causes, under the same experimental conditions, a heating of the tobacco and, therefore, an increase in temperature which is considerably raised above that of the thermostatic oven. The formation of benzopyrenes was found to depend very much upon the flow rate. Moisture content, packing density and other geometrical factors have also a strong effect on the amount of polycyclic hydrocarbons formed during combustion. The quantities of benzopyrenes produced under equal experimental conditions by pyrolysis of other organic materials such as glucose and paraffin wax have been found to vary markedly (1:100 proportion). The yields of benzopyrenes produced by pyrolysis of tobacco (preheated combustion material) with the introduction of air into the system do exceed considerably the corresponding amounts obtained by the smoking of cigarettes