SO2 NAAQS Stakeholder Workgroups: Party Like It’s 2010

U.S. EPA has set the stage for 1-hour sulfur dioxide (SO₂) NAAQS stakeholder workgroups to be held on May 30, May 31, and June 1, 2012.  As discussed in previous blog posts, U.S. EPA has hit the pause button regarding requiring individual facilities to perform SO₂ dispersion modeling as part of the 1-hour SO₂ NAAQS implementation and designation process.  The change in tactics is a result of significant concerns that were expressed by comments on U.S. EPA’s draft dispersion modeling guidance for the SO₂ implementation process.  With the dispersion modeling aspect of the implementation out of the way for now, U.S. EPA has scheduled stakeholder workgroups to discuss the most appropriate ways to implement the 1-hour SO₂ NAAQS, essentially resetting the “Maintenance SIP” aspect of the process to the public comment phase (as there was never an opportunity for public comment in 2010 when the final NAAQS was promulgated).  Based on conversations with U.S. EPA, the primary purpose of the industry stakeholder workgroup on July 1, 2012 will be a roundtable discussion on how an enhanced ambient SO₂ monitoring network would be implemented.  As a primer to the workgroup, U.S. EPA has released a “draft” White Paper outlining a series of specific questions related to the number, location, and practical implications (logistics, costs and who will cover them, etc.) of new ambient SO₂ monitors that would be used to develop attainment and nonattainment designations for the 1-hour SO₂ NAAQS.  U.S. EPA will use the information discussed at the stakeholder group to develop a proposed implementation strategy that will include either an enhanced monitoring network, dispersion modeling, or a combination of both (no, the dispersion modeling requirement is not completely off the table). Also, on a related note, U.S. EPA is still finalizing designations for those areas that already had SO₂ ambient monitoring data available.

ALL4 will continue to track the latest developments and will be involved in the May 30 (Washington, DC) and July 1 (Research Triangle Park) stakeholder workgroup.  Stay tuned for a 4 The Record article next month describing the results of the workgroup and the next steps in the process.