Nevada Division of Environmental Protection
  State of Nevada
Division of Environmental Protection
  Bureau of Air Quality Planning
  901 So. Stewart St., Suite 4001 • Carson City, NV 89701
Phone: (775) 687-9349 • FAX: (775) 687-6396
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Emissions Auditing Branch - CEMS and RATAs


CEMS and COMS Audits:

Nevada’s some facilities are required to install Continuous Monitoring Systems (CEMS) to monitor emissions on a continual basis. CEMS involve the sum of activities associated with determining and reporting pollutant emissions from stationary sources. Coal-and oil-fired power plants, municipal and hazardous waste incinerators, cement plants, kraft pulp mills, as well as many other types of industrial sources are required to monitor emissions on a continual basis. The emissions data obtained provide a continuous record that can be used to determine compliance with the permit requirements. Nevada’s Bureau of Air Pollution Control approves the location and type of the CEMS to be installed for each facility based on their specific pollutants.

Emissions monitored by CEMS include: sulfur dioxide, nitrogen oxides, carbon monoxide, carbon dioxide, oxygen, particulate matter, volatile organic compounds, and mercury. Nevada’s Bureau of Air Quality Planning reviews and evaluates facilities CEMS quarterly reports, annual RATA (Relative Accuracy Test Audit) test protocols and test reports to determine facilities’ compliance with the State and Federal applicable regulations (i.e., 40 CFR Part 60 and Part 75). The 40 CFR Part 75 regulations are more stringent and applicable to power generation facilities only. The facilities are also required to develop a Quality Assurance/Quality Control (QA/QC) plan meeting the requirements stated in 40 CFR Part 60 Appendix F and 40 CFR Part 75 Subpart C §75.21 respectively. The plan includes written procedures which should describe in detail, complete, step-by-step procedures and operations for each of the following activities: calibration of CEMS, calibration drift (CD) determination and adjustment of CEMS, preventive maintenance of CEMS (including spare parts inventory), data recording, calculations, and reporting, accuracy audit procedures including sampling and analysis methods, program of corrective action for malfunctioning CEMS, etc.

Some Nevada facilities are also required to install Continuous Opacity Monitoring Systems (COMS) to monitor opacity emissions on a continual basis. The Bureau of Air Quality Planning reviews and evaluates facilities COMS reports as appropriate in reference to 40 CFR Part 60 and Part 75.