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Table 2 Quartile classification of benzene levels in 649 Harris County census tracts, kriged values versus ASPEN estimates.

From: Kriged and modeled ambient air levels of benzene in an urban environment: an exposure assessment study

  1999 ASPEN Modeled Estimates
1998-2000 Kriged Predicted Values Low No. (%) Medium-Low No. (%) Medium-High No. (%) High No. (%)
Low 91 (56.2) 43 (26.5) 20 (12.4) 8 (4.9)
Medium-Low 11 (6.8) 66 (40.7) 50 (31.9) 35 (21.5)
Medium-High 23 (14.2) 14 (8.6) 51 (31.5) 74 (45.4)
High 37 (22.8) 39 (24.1) 41 (25.3) 46 (28.2)
Total 162 (100.0) 162 (100.0) 162 (100.0) 163 (100.0)
  1. Note: kappa = 0.26 (95% confidence interval = 0.20, 0.31)