Quantifying the Efficiency and Equity Implications of Power Plant Air Pollution Control Strategies in the United States
Levy, Jonathan I., Wilson, Andrew M., Zwack, Leonard M., Environmental Health Perspectives
BACKGROUND: In deciding among competing approaches for emissions control, debates often hinge on the potential tradeoffs between efficiency and equity. However, previous health benefits analyses have not formally addressed both dimensions.
OBJECTIVES: We modeled the public health benefits and the change in the spatial inequality of health risk for a number of hypothetical control scenarios for power plants in the United States to determine optimal control strategies.
METHODS: We simulated various ways by which emission reductions of sulfur dioxide (S[O.sub.2]), nitrogen oxides, and fine particulate matter (particulate matter < 2.5 [micro]m in diameter; P[M.sub.2.5]) could be distributed to reach national emissions caps. We applied a source-receptor matrix to determine the P[M.sub.2.5] concentration changes associated with each control scenario and estimated the mortality reductions. We estimated changes in the spatial inequality of health risk using the Atkinson index and other indicators, following previously derived axioms for measuring health risk inequality.
RESULTS: In our baseline model, benefits ranged from 17,000-21,000 fewer premature deaths per year across control scenarios. Scenarios with greater health benefits also tended to have greater reductions in the spatial inequality of health risk, as many sources with high health benefits per unit emissions of S[O.sub.2] were in areas with high background P[M.sub.2.5] concentrations. Sensitivity analyses indicated that conclusions were generally robust to the choice of indicator and other model specifications.
CONCLUSIONS: Our analysis demonstrates an approach for formally quantifying both the magnitude and spatial distribution of health benefits of pollution control strategies, allowing for joint consideration of efficiency and equity.
KEY WORDS: environmental justice, equity, particulate matter, power plant, premature mortality, risk assessment. Environ Health Perspect 115:743-750 (2007). doi:10.1289/ehp.9712 available via http://dx.doi.org/ [Online 22 January 2007]
In many settings there are tensions between efficiency and equity in deciding on optimal pollution control strategies. Within the context of benefit-cost analysis, efficiency may be related to implementing the least-cost control strategy to achieve a given health benefit, or alternatively, to maximizing net benefits. Similarly, equity can involve procedural fairness (i.e., equal involvement in public proceedings) or equity in the distribution of outcomes (Jacobson et al. 2005). Inequity consists of those inequalities that may be considered unjust or unfair
(Macinko and Starfield 2002). Although there are multiple interpretations of these terms, we focus here on efficiency as maximizing the public health benefits of a control measure, and on equality in the distribution of those benefits across at-risk individuals as the dimension of equity that can be included in quantitative analysis.
Given these definitions, although efficiency is incorporated into any health benefits analysis, equity and related distributional issues are often omitted (Yitzhaki 2003). Most regulatory impact analyses have focused exclusively on aggregate benefits [U.S. Environmental Protection Agency (EPA) 1999a, 1999b] without formally considering the geographic or demographic distributions of these benefits. In parallel, many studies of equity or environmental justice did not quantify health risks, instead focusing on proximity to sources (Burke 1993; Pollack and Vittas 1995; Sheppard et al. 1999), emissions (Millimet and Slottje 2002a, 2002b; Perlin et al. 1995), or concentrations (Lopez 2002). Studies that quantified risk inequality (Apelberg et al. 2005; Morello-Frosch and Jesdale 2006) or proposed a framework to do so (Finkel 1990, 1997) focused on characterizing baseline distributions of risk rather than the benefits of control strategies, and the appropriate methodology may differ in this context. …