EPA Proposes that Indiana’s Clark and Floyd Counties Now Meet Federal Air Quality Standard for Ozone, Opens 30-day Comment Period

May 18, 2022

CHICAGO (May 18, 2022) — U.S. Environmental Protection Agency today started a 30-day public comment period on its proposal to redesignate the Indiana portion of the Louisville area to attainment of the 2015 National Ambient Air Quality Standards (NAAQS) for ground-level ozone. Air monitoring data from 2019 through 2021 show the area now meets the national standard set to protect public health. EPA is also proposing to approve Indiana’s maintenance plan to ensure that the area continues to meet the 2015 ozone standard of 70 parts per billion through 2035. The comment period will close on June 17.

“People in the Louisville area are breathing cleaner, healthier air due to EPA’s partnership with the state of Indiana,” said EPA Region 5 Administrator Debra Shore. “Reducing ozone pollution in the air is especially helpful for vulnerable populations.”

EPA worked collaboratively with Indiana and Kentucky to develop strategies to meet the ozone standard in the Louisville nonattainment area which includes Clark and Floyd counties in Indiana and Bullitt, Jefferson, and Oldham counties in Kentucky. EPA anticipates that Kentucky will seek redesignation of its portion of the area in the future.

Ground-level ozone is not emitted directly into the air but is formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react in the presence of sunlight. Emissions from industrial facilities and electric utilities, motor vehicle exhaust, gasoline vapors, and chemical solvents are some of the major sources of NOx and VOCs. Reducing ozone will help people to experience fewer health problems including chest pain, coughing, throat irritation and congestion. Less ground-level ozone will also help to avoid worsening conditions such as bronchitis, emphysema, and asthma, and it will help to avoid reducing lung function or inflaming the linings of the lungs. Children will especially benefit from reduced exposure to ozone because their lungs are still developing.

The improvement in air quality is due to state and EPA programs to reduce NOx and VOC emissions. These control measures include more protective vehicle emissions standards, nonroad engine emissions standards, and programs to reduce emissions from power plants. Nationally, average concentrations of ozone decreased 20% from 2000 to 2020. All other air pollutants regulated under NAAQS – carbon monoxide, lead, nitrogen dioxide, particulate matter and ozone – have also significantly decreased thanks to the various air quality management and control strategies developed and implemented at the local, state, regional, and national level.