Environmental Justice Indices

The EPA calculates 12 Environmental Justice Indices based on a combination of environmental and demographic information. An EJ Index combines demographic factors with a single environmental variable. The EJ Index is higher in block groups with large numbers of mainly low-income and/or minority residents with a higher environmental indicator value.The higher the percentile, the higher the block group ranks compared to other block groups for any given index.

美国环境保护署（EPA）结合环境与人口统计数据，共测算得到12项环境正义指数（Environmental Justice Indices）。每项EJ指数均将人口统计特征与单一环境变量进行整合。当某一普查街区组（block group）内低收入或少数族裔居民占比较高，且环境指标数值更高时，该街区组的EJ指数得分也会更高。对于任一给定的EJ指数而言，百分位数值越高，该普查街区组相较于其他同类街区组的排名就越靠前。