Figure 1.

QQ-plots for (a) benzene, (b) toluene, and (c) ethylbenzene in pre-, post-, and 1-hr post-exposure firefighter breath samples. The R² values are close to 1, indicating that the data are of uniform lognormal distribution. (1a) Benzene: The increase in the vertical scale for post-exposure shows a distinct difference from the pre- and 1-hr post-exposure groups. Difference in slope between post-exposure and the other two lines indicates that the post-exposure data variance is lower. (1b) Toluene: The tails at the low end of the pre- and 1-hr post-exposure distributions indicate that there a several firefighters with toluene levels that are indistinguishable from zero. (1c) Ethylbenzene: A slight decrease in the scale of post-exposure ethylbenzene was observed at the higher end.