Figure 1.

Means for the primary outcome of puff volume, and for the secondary topography measures of puff inhalation duration, interpuff interval, and puff number, in each of the four exposure trials with each of the three tobacco cigarettes in study 1. Also shown are means for the uninstructed smoking (“ad lib”) of own brand in the comparison sample (versus instructed smoking of own brand in study 1). Dashed lines indicate expected values due to instructions for fixed timing and puff number of tobacco cigarettes during puffing procedure.