Air Quality

Clean Air Interstate Rule/Clean Air Mercury Rule

On March 10, 2005, and March 15, 2005, the United States Environmental Protection Agency (EPA) finalized two rules known as the “Rule to Reduce Interstate Transport of Fine Particulate Matter and Ozone (Clean Air Interstate Rule),” (also referred to as CAIR) and the “Standards of Performance for New and Existing Stationary Sources: Electric Utility Steam Generating Units,” (also referred to as CAMR), respectively.

CAIR was published in the Federal Register on May 12, 2005 [70 FR 25162]. South Carolina is one of the 28 states that the EPA found to contribute significantly to nonattainment of the National Ambient Air Quality Standards (NAAQS) for fine particles (PM _2.5) and/or 8-hour ozone in downwind States. Sulfur dioxide (SO₂) is a precursor to PM _2.5 formation, and nitrogen oxides (NOx) are a precursor to both PM _2.5 and ozone formation. South Carolina must revise its State Implementation Plan (SIP) to reduce emissions of SO₂ and/or NOx from electric generating units (EGUs).

CAMR was published in the Federal Register on May 18, 2005 [70 FR 28606] and applies to all fifty states in the US . This amendment to the Clean Air Act reduces mercury (Hg) emissions from new and existing coal-fired electric utility steam generating units by capping Hg emissions at specified, nation-wide levels. South Carolina must develop an implementation plan, referred to as an “111(d) Plan” for Hg emissions reductions. This requires a State rulemaking action followed by submittal to the EPA for review and approval.

EPA coordinated the concurrent release of CAMR with CAIR because a “co-benefit” of implementing the mechanisms for controlling SO₂ and NOx emissions as required by CAIR is the reduction of Hg emissions. Coordinating the development of CAMR with the CAIR rule allows states to take advantage of the Hg emissions reductions that can be achieved by the air pollution controls designed and installed to reduce SO₂ and NOx.

South Carolina must submit its SIP under CAIR to EPA by September 11, 2006, and the 111(d) Plan under CAMR to EPA by November 17, 2006.

For more information on mercury, please visit our mercury website here.

The purpose of this website is to provide information on the Department's activities related to CAIR and CAMR. The information below includes South Carolina State Register publications, notes from meetings and draft and/or final rules. Questions can be directed to Nelson Roberts by calling (803)898-4122 or by emailing robertln@dhec.sc.gov or to Stacey Gardner by calling (803)898-4287 or by emailing gardnesr@dhec.sc.gov.