Figure 5.
Comparison of cancer risk (per million) or hazard index (HI) based on our sampling data and those estimated from the 2014 National Air Toxics Assessment (NATA) (U.S. EPA 2014). Cancer risk and HI for our sample locations were calculated as the ratio between the sample concentration and the corresponding RSL (see Figure 1 legend). For NATA-based risks, sample locations were then mapped to corresponding census tracts, and NATA cancer risk (for benzene [circle] and ethylbenzene [square]) and HI (for toluene [triangle] and xylenes [cross]) for that census tract extracted. (A) Boxplot comparison. (B) Scatter plot comparisons. The dotted lines show the benchmark of cancer risk of 10−6 and HI = 1; the diagonal line is equality.