New Source Performance Standards (NSPS): What Facility Operators Need to Know

Part 3 of CAA’s Clean Air Act series. Read Part 1 on Title V Permits and Part 2 on State Implementation Plans.

Building a new facility, modifying existing equipment, or adding production capacity can bring a new set of federal emission standards into play, including requirements that apply regardless of where a facility is located.

New Source Performance Standards (NSPS) fill a specific role under the Clean Air Act. While State Implementation Plans (SIPs) address how states will meet air quality standards, and Title V permits consolidate applicable requirements into one operating permit, NSPS establish federal performance standards for certain new, modified, and reconstructed stationary sources.

For facility operators, NSPS matter most during project planning. An equipment upgrade, production change, or capacity expansion may also require NSPS applicability review, and if an NSPS applies, the facility may face new emission limits, testing requirements, monitoring obligations, and reporting deadlines.

What Are New Source Performance Standards (NSPS)?

NSPS are federal emission standards authorized under Section 111 of the Clean Air Act. They apply to specific categories of stationary sources that EPA has determined cause, or contribute significantly to, air pollution that may endanger public health or welfare.

NSPS are technology-based standards, set at the level of emission reduction achievable through the best system of emission reduction (BSER) that has been adequately demonstrated, accounting for cost, energy use, and other relevant factors.

Unlike ambient air quality standards, NSPS do not set allowable pollutant levels in outdoor air. They set performance requirements for sources in specific regulated categories. NSPS are codified in 40 CFR Part 60, with each source category addressed in a separate subpart.

How NSPS Differ From Other Air Requirements

NAAQS vs. NSPS

National Ambient Air Quality Standards (NAAQS) set outdoor air quality benchmarks for certain pollutants. NSPS set emission performance standards for applicable stationary sources. The two programs address different questions.

MACT Standards vs. NSPS

Maximum Achievable Control Technology (MACT) standards apply to Hazardous Air Pollutants under Clean Air Act Section 112. NSPS are established under Section 111 and apply to new, modified, or reconstructed sources in listed categories.

State Permit Limits vs. NSPS

NSPS are federal requirements and represent a performance floor. State agencies may impose more stringent permit limits, SIP requirements, or state-level standards on top of applicable NSPS.

What Triggers NSPS Applicability?

NSPS applicability depends on the source category, the affected facility, and the timing and nature of a project. Each subpart has its own definitions, so applicability should be evaluated before construction or modification begins.

Common triggers include:

  • Construction of a new affected facility: Installing equipment that falls within a listed NSPS source category may bring the applicable subpart into play.
  • Modification of an existing affected facility: Under NSPS rules, a modification generally involves a physical or operational change that increases the emission rate of a regulated pollutant. Not every equipment change qualifies; the regulatory definition controls.
  • Reconstruction of an affected facility: Reconstruction can occur when components are replaced to such an extent that the project is treated similarly to constructing a new affected facility. These determinations are fact specific.

NSPS questions commonly come up when facilities install a new boiler, add a stationary engine, upgrade process equipment, expand a production line, or increase capacity. The key question is whether the affected facility falls within a specific 40 CFR Part 60 subpart.

What Do NSPS Require?

Requirements vary by subpart. Depending on the source category, an applicable NSPS may include:

  • Emission limits, including mass-based, concentration-based, or percent-reduction standards
  • Opacity limits, visible emissions requirements, or fuel requirements
  • Initial and periodic performance testing
  • Continuous emission monitoring systems (CEMS) or continuous opacity monitoring systems (COMS)
  • Notifications, recordkeeping, and reporting obligations

In some cases, Method 9 observations may be used to determine compliance with opacity limits under an applicable NSPS. Method 9 is not required for every NSPS source, but it may be part of the compliance picture when a subpart includes opacity or visible emissions standards.

Because requirements vary widely by source category, facility operators should not assume that compliance with one NSPS subpart looks the same as compliance with another.

How NSPS Interact With Air Permitting

NSPS requirements are typically incorporated into a facility’s Title V operating permit, which is one reason applicability matters early in project planning.

A new or modified source may require a construction permit, an NSPS review, and a New Source Review (NSR) analysis simultaneously. These are related but distinct:

  • NSPS determine whether a specific federal performance standard applies to the source
  • NSR determines whether a project triggers permitting requirements based on emissions increases and other thresholds
  • A project can involve both

Many states have delegation authority from EPA to administer and enforce NSPS. Facility operators may work primarily with their state agency while still meeting federal NSPS obligations.

Key Points

  • NSPS set technology-based federal emission standards for certain new, modified, and reconstructed stationary sources
  • Authorized under Clean Air Act Section 111 and codified in 40 CFR Part 60
  • Applicability depends on the source category, affected facility, construction or modification date, and the specific terms of the relevant subpart
  • May include emission limits, performance testing, monitoring, recordkeeping, and reporting requirements
  • NSPS requirements are often incorporated into Title V permits
  • NSPS review often runs alongside NSR analysis, but the two programs serve different purposes
  • Federal NSPS establish a performance floor; state agencies may impose more stringent requirements

Questions About NSPS or Air Compliance?

NSPS applicability is highly fact-specific. A project involving new equipment, modified operations, or replacement of major components may require review before construction begins. Visit CAA’s services page to learn more about compliance support and visible emissions training options.

Author

Compliance Assurance Associates, Inc. (CAA) provides visible emissions training, smoke school certification, and compliance-focused support for clients navigating Clean Air Act requirements. CAA’s team works with students and regulated facilities to support Method 9 certification, in-person smoke school, virtual reality (VR) smoke school options, and related visible emissions training needs.