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News Releases from Region 05

EPA and Indiana Propose Southwest Indiana Now Meets Federal Air Quality Standard for Sulfur Dioxide

Contact Information: 
Joshua Singer (

PETERSBURG, IND. (October 28, 2020) --Today, the U.S. Environmental Protection Agency (EPA) Region 5 Administrator Kurt Thiede and the Indiana Department of Environmental Management (IDEM) announced at the Pike County Courthouse in Petersburg their proposal to formally redesignate the Southwest Indiana area to attainment of the most recent federal air quality standard for sulfur dioxide. Analyses of air monitoring and modeling data show that air concentrations of sulfur dioxide in the area meet the National Ambient Air Quality Standard (NAAQS) for sulfur dioxide.   

“EPA’s partnership with the State of Indiana has resulted in cleaner, healthier air in the Hoosier state,” said EPA Region 5 Administrator Kurt Thiede. “This Administration has prioritized these efforts, with an understanding that a healthy environment is a precursor to a healthy economy. In addition to having cleaner air, once the Southwest Indiana is redesignated, local businesses will face fewer air permitting restrictions, which paves the way for the infrastructure investment and economic development that help create jobs.”

“This proposed redesignation shows the great strides we continue to make in improving Indiana’s air quality,” said IDEM Commissioner Bruno Pigott. “Because of our strong partnership with EPA, more Hoosiers are breathing cleaner air than ever before.”

EPA worked collaboratively with IDEM to develop strategies for attaining the sulfur dioxide standard in the Southwest Indiana area, which consists of portions of Daviess and Pike Counties. The Southwest Indiana area sulfur dioxide concentrations have decreased substantially due to improvements in flue gas desulfurization control equipment installed at the Indianapolis Power and Light Petersburg Generating Station to meet recently approved emission limits, along with the permanent closure of the Hoosier Energy Ratts Generating Station and national sulfur dioxide control strategies.

EPA is proposing to redesignate the Southwest Indiana area to attainment and to approve Indiana’s maintenance plan to ensure that the area will continue to meet the sulfur dioxide standard. The redesignation will not be final until the public has had an opportunity to comment on the proposal. If the Southwest Indiana area is redesignated, it will meet all NAAQS.

Reduced sulfur dioxide in the atmosphere means cleaner healthier air for the residents of Southwest Indiana, especially children, the elderly, and those who suffer from asthma and are particularly sensitive to effects of sulfur dioxide. Reduced levels of sulfur dioxide and other sulfur oxides is also good for the environment. A decrease in these compounds means less chances of haze and acid rain, which can harm sensitive ecosystems.

Nationally, average concentrations of sulfur dioxide decreased 82% from 2000 to 2019. 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.

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