For each participant, topography measures were obtained by averaging the measures from five artifact-free puffs, as previously reported [25, 26]. Additionally, the first and last puffs of the cigarette were not included in the averages, nor were puffs whose volumes were below 15ml (considered artifacts) or above 400 mL (age-adjusted average tidal volume). Dependent variables included mean puff volume (mL), mean puff duration (msec), mean inter-puff interval (sec), mean puff velocity (mL/sec), and total puff volume (mL).
