Information and Guidelines
A continuous emission monitoring system (CEMS) is the total equipment necessary for the determination of a gas or particulate matter concentration or emission rate using pollutant analyzer measurements and a conversion equation, graph, or computer program to produce results in units of the applicable emission limitation or standard.
CEMS are required under some of the EPA regulations for either continual compliance determinations or determination of exceedances of the standards. The individual subparts of the EPA rules specify the reference methods that are used to substantiate the accuracy and precision of the CEMS.
Performance Specifications are used for evaluating the acceptability of the CEMS at the time of or soon after installation and whenever specified in the regulations.
Quality assurance procedures in Appendix F to 40 CFR 60 are used to evaluate the effectiveness of quality control (QC) and quality assurance (QA) procedures and the quality of data produced by any CEMS that is used for determining compliance with the emission standards on a continuous basis as specified in the applicable regulation.
A predictive emission monitoring system (PEMS) is the total equipment necessary for the determination of a gas concentration or emission rate using process or control device operating parameter measurements and a conversion equation, a graph, or computer program to produce results in units of the applicable emission limitation or standard. The EPA is studying the applicability of PEMS for NOx compliance determinations for various sources. A draft protocol for assessing the accuracy and precision of PEMS has been developed and is expected to be proposed sometime in the near future.
Many of the documents are PDFs, except where indicated. You will need Adobe Reader to view the files on this page. See EPA’s About PDF page to learn more.
- Example Specifications and Test Procedures for Predictive Emission Monitoring Systems (PDF)
- Guidelines for CEMS for Municipal Waste Combustors (PDF) September 1990
- 40 CFR Part 60 Appendix B, Performance Specification 2: Definition Of Normal Load (PDF) March 2, 1992
- Ammonia CEMS Background Report for the Development Of Ammonia CEMS Performance Specifications (PDF) June 1993
- Memo: Use of Acid Rain CEMS as NSPS CEMS (TXT) September 1993
- Determination of the Presence of Stratification of Gaseous Pollutant and Diluent Emissions for CEM or Reference Method Relative Accuracy Locations (PDF) June 21, 1994
- Evaluation Procedure for Multi-Hole Sample Probes (PDF) March 14, 1995
- CEMS Guidelines for MWC (NESCAUM). Model. Program Version 2.0 (TXT) Program purchase information. August 1995
- Federal Register RFP Announcement: CEM Demonstration for Particulate Matter and Mercury (PDF) February 1996
- Site-Specific Quality Assurance Test Plan PM CEMS Demonstration, Volume I (Zipped PDFs) August 7, 1996
- Particulate Matter CEMS Demonstration Test - Status Report 4 (Zipped PDF) February 12, 1997
- Alternative Monitoring Protocol Predictive Emission Monitoring System To Determine NOx And CO Emissions From An Industrial Furnace (PDF) 1997
- Alternative for Analyzing Calibration Gas Cylinders (PDF) February 18, 1997
- Fabric Filter Bag Leak Detection Guidance (PDF) September 1997
- Handbook for CEMS for Non-Criteria Pollutants (PDF) August 1997
- Evaluation of Particulate Matter Continuous Emission Monitoring Systems Final Report (PDF) September 2000
- Current Knowledge of Particulate Matter (PM) CEMS Report (PDF) September 2000
- CEMS Cost Model (XLS) March 7, 2007
Evaluation and Comparison Of U.S. And EU Reference Methods for Measurement of Mercury, Heavy Metals, PM2.5 And PM10 Emissions From Fossil-Fired Power Plants, Final Report (PDF)(313 pp, 8 MB,
Report prepared for the US EPA, et al
Long-Term Field Evaluation of Mercury (Hg) Continuous Emission Monitoring Systems: Coal-Fired Power Plant Burning Eastern Bituminous Coal and Equipped With Selective Catalytic Reduction (SCR), Electrostatic Precipitator (ESP), and Wet Scrubber (PDF)(142 pp, 929 K,
November 29, 2006)
Field Activities From November 2004 to September 2005, Final Report