Levels were also significantly higher in the afternoon in Bangkok school children than in the morning (P < 0.05), while there were no significant differences in the morning and afternoon levels in Chonburi school children. There was a significant correlation (r = 0.368, P < 0.005) between afternoon urinary t,t-muconic acid levels and individual exposure levels.
Individual exposure to total PAHs, urinary 1-OHPlevels, and DNA adduct levels measured in school chil- dren are summarized in Table 3. Individual exposure to total PAHs is 3.5-fold greater in Bangkok school chil- dren compared to Chonburi school children (P < 0.001). In all school children, afternoon urinary 1-OHPlevels, or levels the next morning, were not significantly different