Part 75 Policy and Technical Resources

40 CFR Part 75 requires continuous monitoring and reporting of carbon dioxide (CO₂), nitrogen oxides (NO_X), and sulfur dioxide (SO₂) emissions. Most of these emissions are measured with continuous emission monitoring systems (CEMS). The CEMS monitor the pollution emitted from a smokestack (pollutant concentration) and the volume of exhaust gases (stack gas volumetric flow rate). The regulation also specifies quality assurance and quality control tests to ensure the CEMS are performing properly. Some power plants may use alternative methods with safeguards in place to ensure that emissions are not under-reported.

The links and documents below provide access to a variety of resources useful in understanding emissions monitoring and reporting; if the resources you’re searching for aren’t found below, please submit a comment via the Contact Us form. 

• Plain English Guide to the Part 75 Rule (pdf) (823.46 KB, June 2009)

  A plain-English guide to help interested parties navigate the complex part 75 continuous emission monitoring rule. This guide may be useful to people responsible for complying with the rule, regulatory agencies assessing compliance with the rule, and others who want a general understanding of the emissions monitoring approach used in EPA’s emissions control programs for the power sector.

• Part 75 Emissions Monitoring Technical Questions and Answers

  The Part 75 Emissions Monitoring Technical Q&A (formerly referred to as the Policy Manual) is a series of technical questions and answers (Q&As). EPA will issue new or revised Q&As as they arise. If, after reviewing the regulations and these Q&As, you have additional questions, contact the relevant Emission Monitoring Contact at EPA headquarters.

• Part 75 Petition Responses

  Information about the part 75 petition process and a list of EPA's responses (in chronological order) to part 75 petitions since 2001.

• Part 75 Regulatory Actions

  The regulatory history and actions related to part 75 along with links to the accompanying federal register notices and other resources.

• Eliminating Bias in Monitoring Systems

  A guide to eliminating bias in CEMS. Power plants with CEMS can eliminate bias from monitoring systems by instituting appropriate installation, operation, and quality assurance procedures.

• Control Chart Methodology for Detecting Under-reported Emissions (pdf) (390.37 KB, December 2016)

  An overview of the methodology that EPA uses to identify potential leaks in a CEMS.

• Air Emissions Testing Body (AETB)

  Part 75 relative accuracy test audits (RATAs) or stack tests must use an Air Emission Testing Body (AETB) to conduct the test. An owner or operator who believes that the information provided by the AETB was either incomplete or inaccurate may request assistance in remedying the alleged failure(s). See Part 75, Appendix A, §6.1.2(g) for more information.