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  2. Air Quality Implementation Plans

Development of Specific Elements for Each of the Major SIP Types

Infrastructure SIP

An infrastructure SIP, or i-SIP, is a requirement for all states, regardless of designation. Even areas in attainment must demonstrate what controls they will continue to use and regulate in order to remain in attainment.

Nonattainment New Source Review SIP

  • EPA's New Source Review (NSR) program requires stationary sources of air pollution to get permits before construction starts:
    • Search the NSR Policy and Guidance Document Index (hint: use the Filter box at the top right of the index to search titles by keyword)
  • Startup, shutdown, and malfunction (SSM) emissions

Nonattainment area SIP, a.k.a. attainment demonstration SIP

  • If an area is designated as nonattainment, the state must develop an additional SIP detailing the path to attainment. The SIP will require different elements depending on how far the area is from being able to reach attainment.
    • See the list of all nonattainment SIP requirements
    • See which SIP requirements apply at each ozone nonattainment classification level

Ozone Transport Region (OTR) SIP

  • New source review (NSR) program.
    • NSR offset ratio 1.15:1
    • major source threshold 50 tons per year (tpy) for VOC
    • major source threshold 100 tons per year (tpy) for NOx
  • Major source volatile organic compounds/nitrogen oxides (VOC/NOx) reasonably available control technology (RACT).  See 184(b)(1)(B): Plan provisions for States in Ozone Transport Regions
  • All control technique guidelines (CTGs) reasonably available control technology (RACT). See CTGs 
  • Enhanced emissions inspection and maintenance (I/M) program.

For more information, see 40 CFR 51.1116: Requirements for an Ozone Transport Region. 

Interstate transport SIP

  • Interstate Air Pollution Transport: upwind transport of pollutants across state borders makes it difficult for downwind states to meet health-based air quality standards for ozone.

Redesignation SIP, or maintenance SIP

  • Redesignations and Clean Data Policies
  • Demonstrate attainment using air quality modeling and other analyses

Air Quality Implementation Plans

  • About Air Quality Implementation Plans
  • Approved Air Quality Implementation Plans
  • Develop an Air Quality SIP
  • Find a Regional Contact for Air Quality SIPs/FIPS/TIPs
  • Tools for SIP Status
Contact Us about Air Quality Implementation Plans
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on June 21, 2024
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