Ozone State Planning

The Clean Air Act regulates ozone as a criteria pollutant. The U.S. Environmental Protection Agency (EPA) sets National Ambient Air Quality Standards for ozone (O₃). These standards include both primary standards to protect public health and secondary standards to protect the environment. EPA reviews pollutant standards every five years. Sometimes, a review results in a tightened standard. The first ozone standard was published in 1979 and based on one-hour average concentrations. In 1997, EPA revised the ozone standard based on eight-hour average concentrations. In 2008, and again in 2015, EPA revised the ozone standard. Both revisions lowered the standard level, but were still based on eight-hour average concentrations.

The ozone standards below include the state implementation plan elements developed for each of the standards and the relevant documents associated with the boundary designations. If you are looking for a document that is not available on our website, please submit a Open Records/ Sunshine Law Request.