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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 of 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, Porter, Clark, and Floyd Counties
  • Documents – September 10, 2021 to January 21, 2021 [ZIP]:
    • 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 – December 29, 2020 to November 21, 2017 [ZIP]:
    • 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
  • Documents – June 13, 2007 to May 10, 2007
    • Technical Addendum for the Attainment Demonstration and Technical Support Document [ZIP]
    • 8-Hour Ozone Attainment Demonstration Submittal to U.S. EPA (June 13, 2007)
      • Part 1 [ZIP]:
        • Transmittal Letter, Technical Support Document (TSD) and Appendices A-C
        • Appendix D
        • Appendix E
      • Part 2 [ZIP]:
        • Appendices F-K
        • Appendix L
    • Interested Parties Memo Concerning Availability of Draft Attainment Demonstration Plan (May 10, 2007) [ZIP]
Lake and Porter Counties
  • Documents – June 5, 2009 to October 25, 2007
    • 8-Hour Ozone Attainment Demonstration and Technical Support Document for the Indiana Portion of the Chicago-Gary-Lake County, IL-IN “Moderate” Ozone Nonattainment Area, Lake and Porter Counties, Indiana (June 2009)
      • Part 1 [ZIP]:
        • Technical Support Document and Appendices A-B
        • Appendices C1-C2
        • Appendix C3
        • Appendix D
        • Appendices E- F
      • Part 2 [ZIP]:
        • Appendix G
        • Appendices H-J
        • Appendix K, Part 1
        • Appendix K, Part 2
      • Part 3 [ZIP]:
        • Appendix K, Part 3
        • Appendix K, Part 4
        • Appendix L
    • A transmittal letter is included in Indiana’s Request for Redesignation and Maintenance Plan for Lake and Porter Counties (June 5, 2009) under the 1997 8-hour ozone standard on the Lake and Porter Counties Request for Redesignation and Maintenance Plan page.
    • Lake and Porter Counties - One Hour Ozone Clean Data Demonstration (October 25, 2007) [ZIP]