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Ozone (O3) Attainment Demonstrations

This page is dedicated to attainment demonstrations for the 8-hour ozone National Ambient Air Quality Standards (NAAQS). An attainment demonstration describes measures Indiana is taking to improve air quality and achieve the NAAQS in areas that did not meet the standards when United States Environmental Protection Agency (U.S. EPA) issued designations.

IDEM submits attainment demonstrations to U.S. EPA according to requirements in the federal Clean Air Act (CAA) at Title I, Part D, Subpart 1, Section 172. Once a nonattainment area meets CAA requirements, IDEM asks U.S. EPA to redesignate the area to attainment status. IDEM’s Nonattainment Status for Indiana's Counties page contains a map of current nonattainment areas and historical information.

Following are attainment demonstrations IDEM has prepared and submitted to U.S. EPA for review under the 8-hour ozone standards.

2015 8-Hour Ozone Standard

Lake and Porter Counties
Lake, Porter, Clark, and Floyd Counties
  • Documents – July 5, 2022 to January 21, 2021 [ZIP]:
    • Federal Register Notice Concerning U.S. EPA Approval of the Clean Air Act Section 172 and 182 State Implementation Plan Submittal Requirements for Indiana’s Portion (Clark and Floyd Counties) of the Louisville, Kentucky-Indiana (KY-IN), 2015 8-Hour Nonattainment Area (July 5, 2022)
    • Update and Replacement for the January 21, 2021, Clean Air Act Sections 172 and 182 State Implementation Plan Submittal for Indiana’s Portion of the Chicago, Illinois-Indiana-Wisconsin (IL-IN-WI) 2015 8-Hour Ozone Nonattainment Area Including: Revised 2017 Base-Year Emissions Inventory for Lake (Partial) and Porter (Partial) Counties, Certification of Indiana’s Nonattainment New Source Review (NNSR) Plan, and Revised Certification of Indiana’s Emissions Reporting Rule (September 10, 2021)
    • Clean Air Act Sections 172 and 182 State Implementation Plan (SIP) Submittal for Areas Designated as “Nonattainment,” “Marginal” under the 2015 8-Hour Ozone National Ambient Air Quality Standards, including Calumet, Hobart, North, Ross, and St. John townships in Lake County, and Clark and Floyd Counties (January 21, 2021)

2008 8-Hour Ozone Standard

Lake and Porter Counties
  • Documents – June 28, 2022 to May 20, 2022 [ZIP]:
    • Request for Withdrawal of the February 28, 2017 Attainment Demonstration and Technical Support Document for Indiana’s Portion (Lake and Porter Counties) of the Chicago-Naperville, IL-IN-WI, 2008 8-Hour Ozone Nonattainment Area (June 28, 2022)
    • Federal Register Notice Concerning U.S. EPA Approval of the Clean Air Act Section 172 and 182 State Implementation Plan Submittal Requirements for Indiana’s Portion (Lake and Porter Counties) of the Chicago-Naperville, Illinois-Indiana-Wisconsin (IL-IN-WI) 2008 8-Hour Ozone Nonattainment Area (May 20, 2022)
  • Documents – January 18, 2022 to November 21, 2017 [ZIP]:
    • Supplement to the Updated Section 182(f) NOx RACT Exemption Request and Technical Addendum to the Section 182(c)(3) Certification of the Enhanced Inspection and Maintenance (I/M) Program for Indiana’s Portion (Lake and Porter Counties) of the Chicago-Naperville, IL-IN-WI, 2008 8-Hour Ozone Nonattainment Area (January 18, 2022)
    • Updated Section 182(f) NOx RACT Exemption Request for the Indiana Portion (Lake and Porter Counties) of the Chicago-Naperville, Illinois-Indiana-Wisconsin (IL-IN-WI) 2008 8-Hour Ozone Nonattainment Area (November 30, 2021)
    • Attainment Demonstration and Technical Support Document, 2011 Revised Base-Year Emissions Inventory, 2020 9% Rate of Progress Plan and 3% Contingency Measures Plan, and Certification of Existing Programs for Lake and Porter Counties, Transmittal Letter (December 29, 2020)
      • Attachment A and Appendix A1
      • Appendices A2 and A3
      • Attachments B-I
    • Withdrawal and Replacement of Section 182(f) NOx Exemption Request for the Indiana Portion (Lake and Porter Counties) of the Chicago-Naperville, Illinois-Indiana-Wisconsin (IL-IN-WI) 2008 8-Hour Ozone Nonattainment Area (January 22, 2020)
    • Federal Register Notice Concerning U.S. EPA Approval and Promulgation of Indiana’s Reasonably Available Control Technology (RACT) State Implementation Plan (SIP) Revision and Negative Declaration for the Oil and Natural Gas Industry Control Techniques Guidelines (CTGs), (December 13, 2019)
    • Federal Register Notice Concerning U.S. EPA Approval and Promulgation of Reasonable Further Progress Plan and Other Plan Elements for Indiana’s Portion (Lake and Porter Counties) of the Chicago-Naperville, IL-IN-WI, 2008 8-Hour Ozone Nonattainment Area (February 13, 2019)
    • Reasonably Available Control Technology (RACT) State Implementation Plan (SIP) Revision and Negative Declaration for the Oil and Natural Gas Industry Control Techniques Guidelines (CTGs), (October 25, 2018)
    • Clarification Letter to U.S. EPA Regarding the 2011 Base Year Emissions Inventory for Indiana’s Portion (Lake and Porter Counties) of the Chicago-Naperville, IL-IN-WI, 2008 8-Hour Ozone Nonattainment Area (November 21, 2017)
  • Documents – February 28, 2017 to February 10, 2017 [ZIP]:
    • Section 172 and 182 Requirements for Indiana’s Portion (Lake and Porter Counties) of the Chicago-Naperville, IL-IN-WI, 2008 8-Hour Ozone Nonattainment Area, Transmittal Letter (February 28, 2017)
      • Attachment A
      • Attachments B-C
      • Attachments D-G
    • Section 182(f) NOx Exemption Request for the Indiana Portion (Lake and Porter Counties) of the Chicago-Naperville, Illinois-Indiana-Wisconsin (IL-IN-WI) 2008 8-Hour Ozone Nonattainment Area (February 10, 2017)

1997 8-Hour Ozone Standard

Dearborn County
Lake and Porter Counties

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