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U.S. EPA Finalizes CSAPR Update

Posted: April 5th, 2021

Authors: Amy M. 

U.S. EPA finalized updates to their Cross State Air Pollution Rule (CSAPR) on March 15 to address 22 states’ good neighbor obligations for the 2008 Ozone National Ambient Air Quality Standard (NAAQS).  The original CSAPR update was published in 2016 but found to be only a partial remedy for 21 states (Tennessee’s plan was considered to be sufficient) because it did not do enough to address upwind states’ obligations with respect to ozone transport and U.S. EPA’s analysis considered the year 2023, not 2021 (the serious area attainment date for the 2008 NAAQS).  Read our November 2020 blog for some history and a detailed discussion on the analysis performed for the current update rule.

The March 2021 final CSAPR update addresses good neighbor obligations for those 21 states, finding that 9 states’ implementation plans are sufficient (Alabama, Arkansas, Iowa, Kansas, Mississippi, Missouri, Oklahoma, Texas, and Wisconsin) and finalizing amendments to 12 states’ plans (Illinois, Indiana, Kentucky, Louisiana, Maryland, Michigan, New Jersey, New York, Ohio, Pennsylvania, Virginia, and West Virginia).  U.S. EPA is issuing new or amended Federal Implementation Plans (FIPs) for these 12 states to replace their existing CSAPR NOx Ozone Season Group 2 emissions budgets for electricity generating units (EGUs) with revised budgets via a new CSAPR NOx Ozone Season Group 3 Trading Program.

The enhanced control stringency represented by the new EGU NOx ozone season emission budgets for the 12 states will take effect 60 days after publication in the Federal Register, which corresponds to the effective date of the rule as a whole. U.S. EPA determined that optimization of existing selective catalytic reduction (SCR) controls and existing selective non-catalytic reduction (SNCR) controls and installation of state-of-the-art NOx combustion controls at EGUs are cost effective means of reducing downwind impacts. Due to timing considerations, requirements for installation of state-of-the-art combustion controls will not take effect until the 2022 ozone season. U.S. EPA is further adjusting the states’ emission budgets for each ozone season from 2022 to 2024 to incentivize ongoing operation of identified NOx emission controls to address significant contribution, until such time that air quality projections demonstrate resolution of the downwind nonattainment and/or maintenance problems for the 2008 ozone NAAQS at the four identified monitors (three in Connecticut and one in Texas).  Table I.B-1 in the preamble lists the 2021-2024 budgets by state.

What’s next?  EPA will look at whether further reductions are necessary to address compliance with the 2015 ozone NAAQS, which could include controls for non-EGUs.  The emissions and controls information available for non-EGUs is based on what states report to the National Emissions Inventory (NEI) and is not as complete as the information available for EGUs.  However, U.S. EPA will likely refine its current analysis of what emissions reductions are available from various industrial sectors and emissions unit types, determine the cost of the reductions, and then determine if the identified cost-effective emissions reductions are needed to make progress toward attainment of the 2015 ozone NAAQS in downwind states.  If you have any questions about the CSAPR update, please reach out to Amy Marshall.


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