CEMS Report Format

The monthly or quarterly continuous emissions monitoring system (CEMS) report submitted to IDEM should contain the information listed below. Monthly reports must be received by the Office of Air Quality (OAQ) Compliance Branch within 15 calendar days after the end of each month, and quarterly reports must be received by the OAQ Compliance and Enforcement Branch within 30 calendar days after the end of each quarter. All times must be reported in real time. The following information shall be reported:

A. Plant Operations Downtime Summary:

1. Date of facility downtime
2. Time of commencement and completion of downtime
3. Reason(s) for the downtime
4. Total facility downtime for each month or quarter

B. Excess Emissions Summary:

Excess emissions shall be reported in units of the applicable standard.

1. Date of excess emission(s)
2. Time of commencement and completion
3. Magnitude
   1. For opacity:
      1. The actual percent opacity of all 6-minute (block) averages exceeding the applicable opacity limit shall be reported. If the exceedance occurs continuously beyond one 6-minute period, the percent opacity for each 6-min. period or the average opacity for the entire period shall be reported.
      2. For other IDEM-approved averaging times equal to or greater than 30 minutes, the actual percent opacity of each averaging period in excess of the applicable limit shall be reported. (i.e., for a 30-min. averaging period, each 30-min. exceedance is reported.)
   2. For gaseous, particulate matter, and mercury emissions, the excess emissions in units of the applicable standard in accordance with the applicable averaging time (1-hr block, 3-hr block, 3-hr rolling, etc.) shall be reported. The averaging time is specified in the applicable federal/state rule(s) and may also be specified in the facility operating permit.
4. Reason(s) for the excess emission(s)
5. Corrective action(s) or measures taken to minimize emissions

C. CEMS Instrument Downtime Summary:

1. Date of downtime
2. Time of commencement
3. Duration of downtime
4. Reason(s) for the downtime(s)
5. Nature of system repairs and adjustments

Note: A log of all CEMS downtimes, repairs, adjustments, maintenance, calibrations, audits, and testing shall be maintained and be made available for review by IDEM, U.S. EPA, or their authorized representative.