GLOSSARY OF TERMS: Emissions Monitoring


ACCURACY: The difference between the flow output of a Continuous Emissions Monitoring System and the reported flow output from an approved EPA reference method measured over the same period of time.

AVERAGING PERIOD: A period of time over which a pollutant is averaged to demonstrate compliance to an emission standard.

BLOCK AVERAGES: The total time expressed in fractions of hours over which emission data is collected and averaged.

CALIBRATION DRIFT: The difference between a single raw flow value of the Emissions Monitoring System and a single raw value reported by the approved reference method.

CEMS: A Continuous Emissions Monitoring System is equipment required to determine gaseous emissions rates and record that data.

CHANNEL: The pollutant, diluent, or opacity to be monitored in a Continuous Emissions Monitoring System.


DESCRIPTION REPORT: A short and accurate description of events that caused Continuous Emissions Monitoring System irregularities or excess emissions that occurred during a reporting period.

EXCESS EMISSIONS: The amount by which recorded emissions exceed those allowed by approval orders, operating permits, or the State implementation plan.

MONITOR: The equipment in a Continuous Emissions Monitoring System that analyzes gas concentration and generates an electronic signal that is sent to a recording device.

OPERATIONS REPORT: A report containing all of the regulatory information required of a utility or fossil fuel-fired boiler.

PRECISION: The difference between a Continuous Emissions Monitoring System response and the known concentration of a calibration gas.

QUALITY ASSURANCE: For a Continuous Emissions Monitoring System, the result of the calibrations, drift adjustments, and preventative maintenance activities.

RAA: Relative Accuracy Audit is the primary method of determining the correlation of Continuous Emissions Monitoring System data to simultaneously collected reference method test data.

RATA: A Relative Accuracy Test Audit compares data from a Continuous Emissions Monitor System to independent Reference Method data.

RAW SYSTEM RESPONSE: A Continuous Emissions Monitoring Systems’ uncorrected response used to determine calibration drift.

SUMMARY REPORT: The summary of all monitor and excess emission information recorded during a report period.

The terms and definitions for this issue’s Word Search were contributed by Gary Russell, Production and Flow Engineer for Sage Metering Inc. (www.sagemetering.com). Sage Metering is a manufacturer of monitoring and measurement instruments for gas mass flow applications.