Tobacco industry research and efforts to manipulate smoke particle size: implications for product regulation.

Over the past half-century of cigarette design, tobacco manufacturers have prioritized efficiency of delivery alongside ease of inhalation and use. As a result, the modern cigarette is uniquely effective at facilitating the absorption of nicotine as well as carcinogens and other toxins. The present study draws on internal tobacco company documents to assess industry consideration of the role of smoke particle size as a potentially controllable influence over inhalation patterns and lung exposure. Tobacco manufacturers evaluated particle size manipulation both as a means of controlling physical and sensory product attributes and as a possible approach to reducing health hazards related to exposure. Industry scientists concluded that the smoke aerosol particle distribution of conventional cigarettes, constructed within common parameters, falls within a narrow and effective inhalation range. However, the internal findings suggest that differences in smoke particle size distribution are possible through less conventional approaches to product design. We propose that particle size be included among the many design features to be considered in emerging tobacco product regulation. However, the present review does not address whether particle size regulation would be a plausible means of substantially reducing addictiveness or harmfulness of cigarettes, and therefore we do not propose it as a high-priority target for regulation.