In 1979, the United States Environmental Protection Agency (U.S. EPA) set a 1-hour ozone standard of 120 parts per billion (ppb). The federal Clean Air Act, as amended in 1990, requires areas that exceed the health-based national ambient air quality standards to develop State Implementation Plans (SIP) that demonstrate how they will attain the standards by specified dates. Under the 1979 1-hour ozone standard, there are six areas in California required to develop SIPs, containing eleven separate air pollution control districts. The ozone plans were due and submitted to the U.S. Environmental Protection Agency on November 15, 1994, as a revision to the California State Implementation Plan (SIP).
The California SIP is organized into four separate volumes. Volume I provides background on the 1994 ozone plans, describes the state's overall attainment strategy, and addresses the legal requirements for approval. Volume II contains the California Air Resources Board's comprehensive plan for further reducing emissions from mobile sources and consumer products. Volume III summarizes the status of SIP elements being prepared by CARB's partner agencies: the Bureau of Automotive Repair (enhanced vehicle inspection and maintenance) and the Department of Pesticide Regulation (pesticide controls). Volume IV describes the ozone attainment strategy for each serious, severe and extreme nonattainment area and discusses special policy issues raised by individual local plans.