This study included three different experiments for benzene exposures associated with active smoking. In the first experiment, the mean exhaled breath benzene concentrations measured 1 min after an active smoke ranged from 58.1 to 81.3 microgram/m(3), depending on the commercial cigarette brand, while those measured prior to an active smoke ranged from 15.9 to 19.2 microgram/m(3). The postexposure breath concentrations were much higher than the mean breath concentrations reported by some previous studies whose exposure conditions and postsampling times were not controlled. Similar to some previous decay studies conducted for different volatile organic compounds in different microenvironments, our second experiment showed that there was a rapid fall in the breath concentration and thereafter the decrease was much slower. One-compartment half-lives ranged from 30.1 to 57.8 min. Two-compartment half-lives ranged from 3.2 to 25.7 min for the first half-life and from 67 to 462 min for the second half-life. In the final repeated smoke experiment conducted with two specified time intervals, the breath concentrations showed increasing trends for both the pre- and the post exposure concentrations, with few exceptions. However, none of the changes were statistically significant at P<0.05.
Copyright 2000 Academic Press.