Figure 3.

Measurements of plasma cotinine, exhaled CO and COHb. Concentrations of plasma cotinine were measured by ELISA, and the exhaled CO and COHb levels were determined by a breath CO monitor, as described in the text. Distribution of data within each group is shown by a combination of scatter plots and box and whisker plots, as described in the legend for Figure 1. Comparison between groups was done by the Wilcoxon Rank-Sum test. Panel A shows the results of cotinine measurement, whereas panels B and C display the quantification data for CO and COHb, respectively.