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Archives - March, 2005

Clearer Skies Ahead

On March 10, 2005, EPA issued the Clean Air Interstate Rule (CAIR). CAIR will permanently cap emissions of sulfur dioxide (SO2) and nitrogen oxides (NOX) from electric-generating stations in the eastern United States. CAIR achieves large reductions of SO2 and/or NOX emissions across 28 eastern states and the District of Columbia. When fully implemented, CAIR will reduce SO2 emissions in these states by over 70 percent and NOX emissions by over 60 percent from 2003 levels. In a separate but related action on March 15, EPA issued the final Clean Air Mercury Rule to permanently cap and reduce mercury emissions from coal-fired power plants across the country. When fully implemented, the mercury rule will reduce utility emissions of mercury from 48 tons a year to 15 tons, a reduction of nearly 70 percent. Together the Clean Air Mercury Rule and the Clean Air Interstate Rule create a multi-pollutant strategy to reduce emissions throughout the United States.

For more information, please visit EPA's Clean Air Interstate Rule web page and Mercury Rule web page.

EPA is also considering new approaches for addressing impacts of nitrogen oxides in clean air areas, including national parks and wilderness areas. On February 23, 2005, EPA proposed three options to meet the objectives of the Clean Air Act's Prevention of Significant Deterioration (PSD) program for nitrogen oxides (NOx). These options include:

  1. retaining the existing increments for NOx–measured as nitrogen dioxide (NO2) in the ambient air as established in October 1988;
  2. allowing states that choose to implement an interstate cap and trade program for sources of NOx to rely on the benefits of that program in place of the existing increments to prevent significant deterioration of NOx air quality; or
  3. continuing to allow states to adopt their own planning strategies to show that PSD for NOx is satisfied through some combination of state and federal emissions controls that have been or will be adopted.

The proposal mentions scientific work sponsored by the National Park Service with respect to establishing "critical loads" related to nitrogen impacts on sensitive ecosystems. This scienctific information may be used as part of the basis for showing that PSD for NOx is satisfied under the third proposed option.

This proposed rule complies with a court order and the terms of a settlement agreement with Environmental Defense. The comment period closed on April 25, 2005. The final rule is expected in September 2005.

The EPA recently completed an analysis of the human health and environmental benefits of the Clear Skies Act, which is similar to CAIR. For information on these benefits, see our New Developments webpage.

updated on 06/01/2007  I   http://www.nature.nps.gov/air/hot/archive/200503/headlines.cfm   I  Email: Webmaster