If finalized, the re-classifications will require the state to incorporate requirements, such as lower permitting thresholds and implementing reasonably available control technologies at more sources. It will also give the state more time to meet the federal ozone standard.

The EPA is also proposing a schedule for the state to submit revisions to its clean air plan that show how the area will meet the additional requirements resulting from the re-classifications. The EPA will continue to work with the state and tribes to address the federal Clean Air Act requirements.

Ozone is a gas that occurs naturally in the upper atmosphere to protect earth from the sun’s harmful ultraviolet rays. At ground level, ozone is created by a chemical reaction involving sunlight and pollutants such as car exhaust, oil and gas vapors, and paint and hairspray fumes. Ozone pollution at ground level aggravates respiratory illnesses such as asthma, bronchitis and emphysema. Healthy people who are active outdoors on high ozone days may experience coughing, nasal congestion and itchy eyes.

The public is encouraged to comment during a 30-day comment period that will be identified once the proposed rule is published in the federal register.