Clean Air After the CAIR Decision: Multi-Pollutant Approaches to Controlling Powerplant Emissions

James E. McCarthy
Specialist in Environmental Policy

Larry Parker
Specialist in Energy and Environmental Policy

Robert Meltz
Legislative Attorney

In April 2010, the Environmental Protection Agency (EPA) expects to propose a new Clean Air Transport Rule to control powerplant emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx). When finalized, this rule will replace the Clean Air Interstate Rule (CAIR); CAIR, which was promulgated in May 2005, established a regional cap-and-trade program for SO2 and NOx emissions from electric generating units (EGUs) in 28 eastern states and the District of Columbia. On July 11, 2008, in North Carolina v. EPA, the U.S. Court of Appeals for the D.C. Circuit vacated CAIR, saying that it had "more than several fatal flaws." The court subsequently modified its decision: on December 23, 2008, it reversed itself by allowing CAIR to remain in effect until a new rule is promulgated by EPA. 

From a policy standpoint, the court's July 2008 decision seriously undermined EPA's approach to clean air over the previous eight years. CAIR was the lynchpin that held together the Bush Administration's strategy for attainment of the ozone and fine particulate National Ambient Air Quality Standards (NAAQS), for achieving reductions in mercury emissions from coal-fired powerplants, for addressing regional haze impacts from powerplants, and for responding to state petitions to control upwind sources of ozone and fine particulates under Section 126 of the Clean Air Act. As discussed in this report, the potential impact on communities attempting to achieve NAAQS and the impact on mercury emissions could be substantial, and has prompted some to call for congressional action to address the issue. On February 4, 2010, Senator Carper and 11 cosponsors introduced S. 2995, a multipollutant bill that would replace the CAIR requirements, and require standards for powerplant emissions of mercury. 

EPA's only short-term option, other than letting the decision stand, was to seek further judicial review, a step the agency took on September 24, 2008. This led to the aforementioned D.C. Circuit ruling allowing CAIR to remain in effect until replaced. But the court's July 2008 decision strongly suggests that there is no simple "fix" that will make CAIR acceptable to the court. This left EPA with three clear long-term options: (1) starting anew with a new strategy with respect to mitigating transported air pollution based on the decision; (2) allowing the states to sort out the issue through Section 126 petitions; and (3) seeking new legislation providing EPA with the statutory authority to implement either CAIR in some form, or an alternative. The agency is proceeding with the first of these options, but has indicated that it views congressional efforts to address the issue as "mutually reinforcing." 

For Congress, the decision raises several issues: 

• Should Congress consider providing EPA with the authority to implement CAIR or other cost-based, market-oriented approaches to address NAAQS? 

• Should Congress consider multi-pollutant legislation as a supplement or substitute for the current regulatory regime, at least for electric generating units? 

• Should Congress consider a more comprehensive revision to the Clean Air Act to address the full scope of ozone and PM2.5 NAAQS non-attainment and related issues, as well as mercury emissions from coal-fired powerplants, and emerging environmental issues such as climate change? .


Date of Report: March 4, 2010
Number of Pages: 16
Order Number: RL34589
Price: $29.95

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