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Indiana Department of Environmental Management

Air Quality in Indiana

Air Quality in Indiana > Permits > Air Permit Programs Overview Air Permit Programs Overview

  • Indiana Emission Credit Registry:
    • The Indiana Emission Credit Registry is a tool created to assist sources looking for emission offsets for nonattainment New Source Review (NSR) permitting.
  • New Source Review (NSR):
    • NSR is a permitting program that regulates the construction of new major stationary sources of air pollution such as factories, power plants, smelters and major modifications to existing major sources (For example: replacing and/or adding new equipment). These sources are required by the Clean Air Act to obtain an air pollution permit before beginning construction. NSR has three components: the prevention of significant deterioration (PSD) permitting program for major sources, the nonattainment area NSR permitting program for major sources, and the NSR program for minor sources.
  • NSR Reform Project Update:
    • U.S. EPA published federal NSR reform amendments containing the PSD and non-attainment NSR requirements in the December 31, 2002 Federal Register and equipment replacement provisions in the October 27, 2003 Federal Register. Indiana has taken steps to incorporate the December 31, 2002 amendments into state rule. The state NSR Reform rulemaking became effective on September 9, 2004.
  • PSD Program Approval Summary:
    • On March 3, 2003, U.S. EPA published conditional approval of the PSD program as a revision to the Indiana State Implementation Plan (SIP). The PSD SIP approval became effective on April 2, 2003. Indiana's PSD program is now a federally-approved program instead of a delegated program.
  • Title V Operating Permit Program:
    • Title V of the 1990 Clean Air Act Amendments requires all major sources and some smaller sources of air pollution to obtain an operating permit. A Title V permit grants a source permission to operate. The permit includes all air pollution requirements that apply to the source, including emissions limits and monitoring, record keeping, and reporting requirements. It also requires that the source report its compliance with permit conditions to the Indiana Department of Environmental Management (IDEM).
      • U.S. EPA Title V provides additional information on the Title V Operating Permit Program.
      • On December 4, 2001, U.S. EPA granted final approval of Indiana's Title V Operating Permit Program. Under a court approved settlement, EPA published a notice in December 2000 informing the public of an opportunity to identify any deficiencies in any Title V Operating Permit Program. Several deficiencies were identified in Indiana's program and the rule changes to satisfactorily correct those deficiencies became effective on January 19, 2002.
  • Federally Enforceable State Operating Permit (FESOP):
    • Indiana has developed a State operating permit program that is enforceable by U.S. EPA and allows sources to limit their air emissions to below the Title V threshold levels. A FESOP permit can provide more operational flexibility. Many sources seek a FESOP to limit their emissions and not be subject to the Title V program.
  • Acid Deposition Control Program:
    • The acid deposition control program is a federal program that is enforceable by U.S. EPA. The purpose of this program is to reduce the amount of sulfur dioxide (SO2) and nitrogen oxide emissions (NOx) that go into the air. These two pollutants contribute to the formation of "acid rain." Under this program, U.S. EPA set a limit, or "cap", on the total amount of sulfur dioxide that can be emitted from all regulated power plants in the United States. That amount is 10 million tons less than the total SO2 emissions in 1980.
  • Air Quality Modeling:
    • Air dispersion modeling must be conducted for certain permit applications to demonstrate that a source will not cause or significantly contribute to the violation of air quality standards, PSD increments, or toxic thresholds. This site contains information on Air Dispersion Modeling (including modeling policies), statewide inventory of NAAQS sources, statewide PSD inventory, background concentrations and downloadable meteorological data. IDEM’s Office of Air Quality (OAQ) follows all air quality modeling procedures set forth in the U.S. EPA Guideline on Air Quality Models for PSD, nonattainment New Source Review, and SIP revisions.