Observations on the Distribution of Certain Tobacco Smoke Components with Respect to Particle Size

If the distribution of specific smoke components with respect to particle size were significantly different than the size distribution of particulate matter, a compound or group of compounds might be selectively removed by the selective filtration of a given particle size. Various techniques have been used to determine the particle size distribution of a few smoke components. Berner and Marek used a Goetz aerosol spectrometer to determine the size distribution of potassium in smoke; and Owen, Westcott and Woodman used a conifuge to examine the distribution of three smoke components. In the present work, a cascade impactor was used to separate smoke particles into four fractions of 0.25 to 1.0 µ in diameter based on the principle that particles in a moving airstream impact on a slide placed in their path, if their momentum is sufficient to overcome the drag exerted by the airstream. The particle size distribution of five organic compounds: indole, nicotine, diethyl phthalate, norphytene, and neophytadiene were determined. These size distributions were compared to the distribution of total particulate matter (TPM) and the following observations were made:

1. All compounds were distributed in a pattern similar to that of TPM. Therefore, the selective filtration of a given compound by selective filtration of a given particle size is probably unfeasible.

2. The concentrations of indole and nicotine were higher in the medium-size particles (0.5 to 0.75 µ) than in the small or large particles.

3. It is known that cellulose acetate filters are more efficient for the filtration of small and large particles than they are for medium-size particles. Therefore, the high concentration of nicotine in the medium-size particles may contribute to the slightly higher filtration efficiency these filters have for the TPM than they have for nicotine.