Comment submitted by M. Lopes

As a Corporate Senior Environmental Manager of multiple facilities that have units subject to both Part 60 (NSPS/NSR) and Part 75 (Acid Rain/NOx SIP Call) continuous emission monitoring requirements, I strongly support EPA?s initiative to harmonize the conflicting and duplicative requirements of both regulations and agree with most of the proposed revisions provided in document no. 234 of docket EPA-HQ-OAR-2005-0031. However, EPA?s revisions to the NSPS CEMS requirements as proposed in the document cited above will not accomplish this goal because of the following reasons: 1) The majority of the units affected by these regulations are also required by their permitting agencies to install, maintain, and operate a CEMS to continuously monitor CO emissions at their exhaust stacks. All of the CO analyzer performance specifications and quality assurance procedures are specified only in Part 60. Therefore, unless changes are made to the relevant general sections, Appendix B PS4 and PS4A, and Appendix F of Part 60, these facilities will continue to have conflicting hourly data validation, certification (specially the 7-day drift test) and quality assurance requirements. 2) The original performance specifications developed for Part 60 CEMS were based on analyzers with significantly higher spans than the ones that are currently required by Part 75. In addition, the majority of the existing units are subject to emission limits specified in their air permits that are more stringent than the existing NSPS limits. Some of these units are subject to emission limits as low as 2.5 ppm NOx corrected to 15% O2 and are required to use analyzers with spans of 10 ppm. Therefore, the use of the existing Part 60 performance specifications to these low span monitors can become very strict, as in the case of the RATA specifications, and sometimes meaningless, as in the case of performance of a cylinder gas audit in analyzers with spans lower than 30 ppm. In order to better harmonize the Part 60 and Part 75 requirements I kindly request EPA to evaluate the implementation of the following corrective actions to address the two concerns listed above: 1) Revise the relevant sections of Subpart A and Appendix F to include the CO analyzer. For example, 40CFR 60.13(h)(2) should be revised to state that the hourly data validation procedures specified in this section also apply to the CO analyzers installed to satisfy the continuous monitoring requirements of an air permit and not just a NSPS regulation. Also, for units subject to both Part 60 and Part 75 requirements, Appendix F should allow the quality assurance tests to be performed in all analyzers, including the CO analyzers, at the same frequency as the quality assurance tests performed under Part 75. In this case, the criteria for excessive calibration drift and routine audit inaccuracies specified in Sections 4.3 and 5.2.3 of Appendix F would apply to the CO analyzers instead of the criteria specified in Appendix B of Part 75. 2) Revise the criteria for excessive calibration drift and audit inaccuracies provided in Appendix F to add more representative specifications for analyzers with low spans.