Air Quality

Ozone Boundaries


September 16, 2009:  Stay of the 2008 Ozone Standard Designation Process

The U.S. Environmental Protection Agency (EPA) has announced it will reconsider the 2008 national ambient air quality standards (NAAQS) for ground-level ozone, the primary component of smog. EPA stated that it will reconsider the ozone standards to ensure that two of the nations most important air quality standards are clearly grounded in science, protect public health with an adequate margin of safety, and are sufficient to protect the environment. The Agency will propose any needed revisions to the ozone standards by December 2009 and issue a final decision by August 2010.

For additional information please visit EPA's webpage.

DHEC Update regarding EPA's Stay of the 2008 Ozone Standard Designation Process


South Carolina's 8-Hour Ozone Nonattainment Boundary Recommendations

Introduction

On March 12, 2008, the U.S. Environmental Protection Agency (EPA) strengthened its National Ambient Air Quality Standard (NAAQS) for ground-level ozone.

The new ozone NAAQS are comprised of a revised primary standard to protect health and a revised secondary standard to protect sensitive plants and animals. The EPA revised both 8-hour ground level ozone standards to a level of 0.075 parts per million (ppm). To meet the ozone standard, the 3-year average of the fourth-highest daily maximum 8-hour average ozone concentrations measured at each monitor within an area over each year must not exceed 0.075 ppm.


South Carolina’s Ozone Levels

Based on data from 2006-2008, five counties (Abbeville, Aiken, Pickens, Spartanburg, and York) had one monitor and one county (Richland) had two monitors with concentrations of ozone above the revised standards.

South Carolina’s Ground-level Ozone Data


EPA Designation Process

The federal Clean Air Act requires the EPA to classify areas using these three designations:

  • Attainment, which means the area meets the standards;
  • Nonattainment, which means the area doesn’t meet the standards; and
  • Unclassifiable, which means there isn’t enough data to classify the area under the new or revised standard.

These designations can have important implications for growth and development.

The EPA sets its non-attainment boundaries based on recommendations from the states. States must make their recommendations to the EPA no later than March 12, 2009, for areas to be designated as attainment, nonattainment, and unclassifiable under the revised standard. The EPA will make its final designations by March 12, 2010.

In a memorandum dated December 4, 2008, the EPA provided factors that should be considered in making recommendations for area designations. EPA also recommends that the Core Based Statistical Area (CBSA) or Combined Statistical Area (CSA), which includes two or more adjacent CBSAs, serve as the starting point, or “presumptive” boundary for making these recommendations. The EPA “presumptive boundary” map indicates the affected areas in South Carolina.


Documents

All documents are in pdf format. Some documents are fairly large, and you may want to download them directly rather than viewing them in your browser.


Calendar/Events

Click to view presentations from meetings held around the State announcing the proposed ozone boundaries:

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Links


Contact Information

Nelson Roberts
Manager, Planning Section
Email 803-898-4122

Tommy Flynn
Manager, Data Analysis and Support Section 
Email 803-898-3251

Brian Barnes
Planning Section
Email 803-898-7099

For more information please contact us at (803) 898-4123 or by email.