The EPA has informed 31 governors that areas of their states fail to meet new health standards for ground-level ozone. Part or all of 474 counties nationwide are in non-attainment areas for either failing to meet the eight-hour ozone standard or causing a downwind county to fail. The vast majority of the 2,668 U.S. counties meet the new standards.

The attainment and non-attainment designations take effect on June 15. The EPA also has issued a new rule classifying areas by the severity of their ozone conditions and establishing the deadline for state and local governments to reduce ozone levels. Once designations and classifications take effect this month, states and communities must prepare a plan to reduce ground-level ozone.

Many states received good news: 18 entire states are meeting the more protective standard. The EPA finds found no non-attainment areas in the northwest or in many of the Great Plains, Rocky Mountain and Great Basin states. The entire populations in of Iowa, Minnesota, Florida, Mississippi, Vermont, Hawaii and Alaska are breathing air that meets the new standard.

At the same time, the EPA proposed the Clean Air Rules of 2004, a suite of actions that, taken together, "will produce one of the most productive periods of air quality improvement in the nation's history," according to the agency. The rules include tools to help states and communities meet the national standard for ground-level ozone.

Three of the rules specifically address the transport of pollution across state borders: the Interstate Clean Air rule, Mercury Clean Air rule and Non-road Clean Air rule. The Clean Air Ozone rules classify the seriousness of the problem and require states to submit plans for reducing the levels of ozone in areas where the ozone standards remain unmet. The Clean Air Fine Particle rules requires states to submit plans for reducing particulate pollution levels in areas where the fine -particle standards remain unmet.

A full listing of the EPA's designations of state and tribal areas is available at www.epa.gov/ozonedesignations. To learn about the Clean Air rules of 2004, see www.epa.gov/cleanair2004.