Non-Attainment New Source Review (NNSR)

What is Non-Attainment New Source Review (NNSR)?

Non-attainment New Source (NNSR) is part of the Clean Air Act’s New Source Review (NSR) program, also referred to as the federal preconstruction permitting program. NSR requires industrial facilities to install modern pollution control equipment and obtain permits before construction or major modifications that significantly increase emissions. The NSR has two main subprograms:

1. 1. Prevention of Significant Deterioration (PSD)
      1. Applies to attainment areas (i.e. areas where air quality meets the National Ambient Air Quality Standards)
      2. Refer to SEC’s PSD permits and requirements page for more information
   2. Non-attainment New Source Review (NNSR)
      1. Applies to nonattainment areas where NAAQS are not met
      2. NNSR ensures that new sources or major modifications do not worsen existing air quality issues and that industrial growth contributes to eventual attainment of standards

Who Needs NNSR?

NNSR applies facilities that:

• • Construct a new major source of regulated NSR pollutant in nonattainment areas, or
  • Undergoes a major modification at an existing source, meaning any physical change or change in the method of operation that results in a significant emissions increase (i.e. an increase that exceeds the pollutant-specific significance thresholds under 40 CFR §51.166 and §52.21)

Key NNSR Regulatory Requirements

All NNSR programs require facilities to demonstrate

1. 1. Lowest Achievable Emission Rate (LAER)
      1. The most stringent emission limitation required by regulation or achieved in practice
      2. Unlike Best Achievable Control Technology (BACT) under PSD, LAER does not consider cost when determining feasibility
      3. Refer to SEC’s LAER page for more detailed information
   2. Emission Offsets
      1. Any new or increased emissions must be offset by reductions from existing sources in the same nonattainment area
      2. Offsets ensure that industrial development can occur while driving net emissions reduction, progressing toward attainment
   3. Public Involvement
      1. NNSR requires opportunities for public participation such as:
         1. Comment periods
         2. Public hearings
         3. Appeals processes

Importance of NNSR

NNSR safeguards public health and welfare by ensuring that criteria pollutants do not exceed unsafe levels. SEC provides full-service NNSR support to help facilities assess applicability, prepare necessary documentations, and comply with state and federal regulations.