Urine 1-hydroxypyrene glucuronide concentration plotted by frequency of barbeque preparation and tobacco smoke exposure. We divided subjects into four groups by whether they prepared barbeque at least once a week and whether they were smoke exposed (currently smoked tobacco or had a urine cotinine greater than category 1). Urine 1-OHPG concentration is plotted on the log scale. From left to right, the median for each group is indicated by the horizontal bar and the values are 0.8, 1.7, 3.1, and 3.7, respectively. From left to right, the number of subjects in each group is 60, 25, 85, and 29, respectively.