PER pressure: New Jersey's "Population Emissions Ratio" environmental equity screening model

In recent years, much attention has focused on how to incorporate environmental equity considerations into government permitting programs for environmentally regulated facilities. On February 4, 2002, the New Jersey Department of Environmental Protection (NJDEP) became the first state environmental agency to propose a broad legally binding rule intended to guard against environmental inequity in its permitting decisions. The proposed rule centered on an innovative computerized environmental equity (EE) screening model that used "Population Emissions Ratios" to identify small geographic areas in which environmental equity concerns might exist and to simulate the effect on statewide environmental equity of increasing environmental risks in small geographic areas. The NJDEP's model examined an extensive array of ethnic groups, included a variety of environmental risks, evaluated most of those risks in terms of human health, and used an innovative simulation process designed to identify permitting decisions that would worsen statewide environmental inequity. The results of the NJDEP's efforts, however, pose substantial concerns. For example, some key provisions of the NJDEP's model were inadequately explained and some were illogical and would bias its results. The model might be susceptible to generating implausible results due to small, meaningless, and/or essentially random fluctuations in its data inputs. The model used relatively large geographic areas as the units of analysis and interpolated results between them, rather than using smaller geographic areas and avoiding interpolation errors. Finally, the environmental risks evaluated by the model were both arguably over- and underinclusive. Thus, the NJDEP's efforts, although noteworthy, raised more issues than they settled.