Frequency and durational components of smoking topography were measured by a portable smoking device while 10 subjects smoked four cigarettes ad libitum in a non-laboratory environment. Nicotine blood levels were measured before and after smoking each cigarette and serial blood samples for determining nicotine metabolic half-life were obtained the following day. Results showed that change in pre- and post-cigarette nicotine levels and metabolic half-life for nicotine were not related to within-cigarette topography measures or nicotine yield of cigarette, but were significantly related to intercigarette interval.