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Status of Hg0 and HgCl2 and HCl Reference Gas Standards
Citation:
Ryan, J. AND S. Long. Status of Hg0 and HgCl2 and HCl Reference Gas Standards. The 27th EPRI Continuous Emissions Monitoring User Group Meeting, St. Louis,MO, May 02 - 03, 2018.
Impact/Purpose:
National Institute of Standards and Technology (NIST) traceable, reference gas standards are integral to EPA’s reference methods necessary to implement continuous emissions monitoring systems (CEMS) for regulatory compliance source emissions monitoring, being the basis for calibrating CEMS. The quality and availability of these required reference gases directly impacts EPA's ability to implement emissions monitoring programs. Mercury (Hg) and hydrochloric acid (HCl) are specific reference gases that are required reference gases that have had quality and availability concerns. NIST and EPA are collaborating and have conducted research to overcome issues associated with gaseous elemental mercury (Hg0) and oxidized mercury (HgCl2) reference gases. This collaboration has resulted in the development of a low uncertainty measurement approach that has been demonstrated to be suitable for the accurate measurement of Hg0 and HgCl2 reference gases. This measurement approach has been used to successfully compare the quality of available Hg0 and HgCl2 reference gases and demonstrate their suitability for compliance emissions monitoring. This collaborative research supports impacts of Office of Air Quality and Planning and Standards (OAQPS) regulatory programs and the regulated industrial sources, such as Electric Utilities and Portland Cement plants.
Description:
This presentation will discuss the approach and preliminary results of a joint EPA/NIST study to accurately quantify the true concentrations of Hg0 and HgCl2 reference gases produced from high quality, NIST-traceable, commercial Hg0 and HgCl2 generators. This presentation will also discuss the current regulatory status of NIST-traceable, Hg0, HgCl2 and HCl reference gas standards.