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Air Quality

Regulation and SIP Management

State Implementation Plan

The State Implementation Plan (SIP) is developed to show how a state will meet the National Ambient Air Quality Standards (NAAQS) for six common pollutants, called "criteria pollutants," as set forth by the Clean Air Act.

A SIP is the accumulated record of many documents that form a blueprint and timeline for the state's plans to assure compliance with the NAAQS for criteria pollutants (carbon monoxide, sulfur dioxide, ozone, nitrogen dioxide, lead, and particulate matter), as outlined in the Clean Air Act. SIPs include, among other things, control plans, regulations, inventories of emissions within the state, and transcripts of public involvement in the SIP-development process. Once approved, the SIP is enforceable by the state and EPA. Elements of South Carolina's SIP have been in place since 1972. Though there have been many amendments, there is only one South Carolina SIP. For more information, see EPA's SIP webpage.

End of Year Revisions

Many Bureau of Air Quality (BAQ) regulations are based on U.S. Environmental Protection Agency (EPA) regulations. In some instances, BAQ incorporates EPA regulations by reference. In most examples, this means that reference to EPA regulations appear in a table as part of DHEC regulations, without repeating the entire EPA regulation word for word. Throughout each year, the EPA revises its existing regulations, and publishes new ones. To keep our regulations current, BAQ adopts the relevant new EPA regulations and revisions to existing regulations annually through a process commonly known as the End of Year Revision. BAQ started this process in 2003.

At the end of each year, BAQ reviews regulations that the EPA finalized in that year. In the next year, BAQ starts the regulation development process for incorporating the applicable regulations from the previous calendar year. As a part of this process, BAQ may also make smaller changes to our regulations, such as correcting typographical errors.

In the list below, the years refer to the year in which the EPA issued the final rules, not the year in which DHEC incorporated the regulations. For example, BAQ addressed EPA rules that came out in 2009 in the 2009 End of Year Revisions, a regulation development process that started in early 2010. If the End of Year Revisions do not affect our regulations that are part of the SIP, there will be no SIP revision listed below for that particular year.

To find out more about the steps in the regulation development process, which includes the End of Year Revisions, please see our Proposed and Recent Rulemaking page.


For more information please contact the Bureau of Air Quality at (803) 898-4123 or by email.