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Clean Air Markets

Final Update to NOx SIP Call Regulations

Rule Summary

Update to NOX SIP Call Regulations: Emissions Monitoring Provisions in State Implementation Plans Required Under the NOX SIP Call

EPA is finalizing amendments to the NOX SIP Call regulations. Prior to the amendments, affected states were required to include provisions in their state implementation plans (SIPs) for certain covered facilities to monitor summertime NOX emissions according to 40 CFR part 75, which generally entails the use of continuous emission monitoring systems (CEMS). Most of these facilities – primarily power plants – also perform part 75 monitoring under other programs such as the Acid Rain Program and the Cross-State Air Pollution Rule trading programs, but some of the sources – primarily industrial facilities – perform part 75 monitoring only because of the SIP provisions required by the NOX SIP Call regulations.  Under current circumstances, other forms of monitoring requirements for the remaining sources could provide adequate assurance that the NOX SIP Call’s required emissions reductions will continue to be achieved.  Accordingly, the amendments allow states to amend their SIPs to include alternate, potentially lower-cost monitoring requirements for NOX SIP Call purposes. The increased flexibility provided by this rule will lead to potentially lower monitoring costs for some sources in states that submit approvable SIP revisions.

Rule History

February 26, 2019 - Final Update to NOX SIP Call Regulations

September 13, 2018 - Proposed Update to NOX SIP Call Regulations

Additional Resources