The control and test cigarettes were conditioned for at least 48 h
under a fume hood in their original, sealed packs at 22 ± 2 C and
relative humidity of 60 ± 5%. They were then unpacked and transferred
in sealed storage boxes for transportation to the smoking
machine. The 2R4F cigarettes were conditioned according to ISO
standard 3402 (ISO, 1999).The cigarettes were smoked on a 20-port
Borgwaldt smoking machine RM20H under ISO smoking conditions
(ISO, 1991a). In short, puff volume, puff duration, and puff frequency
for the ISO smoking conditions were 35 ml, 2 s, and 1/min.
Cigarettes were smoked to a final butt length of 35 mm.