Geographic pollution mapping of power plant emissions to inform ex-ante environmental justice analyses

Federal and many state agencies are required to perform environmental justice analyses of their policies prior to implementing them to prevent undue impacts on low income and minority populations. However, little academic attention has been paid to the quality of these ex-ante environmental justice analyses. This investigation evaluates the methods used to perform environmental justice analyses during siting and permitting processes. The study uses both the California Energy Commission guidelines for environmental justice analyses and a method that geographically maps air pollution to perform ex-ante environmental justice analyses of three power plants. The objective is to see if results from using these two analysis methods differ substantially. Findings indicate that the mapping technique employed represents a substantial improvement over defining the impacted population using proximity methods because it accounts for the geographical distribution of the hazard. Furthermore, using multiple comparison benchmarks to determine whether the impacted population constitutes an environmental justice population improves upon existing methods by accounting for the spatial distribution of minority and low income populations and for the possibility that there is a relatively high or relatively low percentage of low income and minority persons in both the impacted and comparison regions.