Average Design Value 2017
                           Maximum Design Value 2017
                            2012-2014 Design Value
                                                                       90013007
Connecticut
Fairfield
                                     84.3
                                     89.0
                                     77.1
                                     81.4
                                     84.0
                                                                       90019003
Connecticut
Fairfield
                                     83.7
                                     87.0
                                     78.0
                                     81.1
                                     85.0
                                                                       90099002
Connecticut
New Haven
                                     85.7
                                     89.0
                                     77.2
                                     80.2
                                     81.0
                                                                      480391004
Texas
Brazoria
                                     88.0
                                     89.0
                                     81.4
                                     82.3
                                     80.0
                                                                      481210034
Texas
Denton
                                     84.3
                                     87.0
                                     76.9
                                     79.4
                                     81.0
                                                                      484392003
Texas
Tarrant
                                     87.3
                                     90.0
                                     79.6
                                     82.1
                                     77.0
                                                                      484393009
Texas
Tarrant
                                     86.0
                                     86.0
                                     78.6
                                     78.6
                                     80.0
                                                                      551170006
Wisconsin
Sheboygan
                                     84.3
                                     87.0
                                     77.0
                                     79.4
                                     81.0

Table V.C-2. Average and Maximum 2009-2013 and 2017 Baseline 8-Hour Ozone Design Values and 2012-2014 Design Values (ppb) at Sites in the Eastern U.S. that are Projected Nonattainment but Currently Measuring Clean Data (Maintenance-Only Receptors)

Monitor ID
State
County
                        Average Design Value 2009-2013
                        Maximum Design Value 2009-2013
                           Average Design Value 2017
                           Maximum Design Value 2017
                            2012-2014 Design Value
                                                                      240251001
Maryland
Harford
                                     90.0
                                     93.0
                                     81.3
                                     84.0
                                     75.0
                                                                      360850067
New York
Richmond
                                     81.3
                                     83.0
                                     76.3
                                     77.8
                                     73.0
                                                                      361030002
New York
Suffolk
                                     83.3
                                     85.0
                                     79.2
                                     80.8
                                     73.0
                                                                      390610006
Ohio
Hamilton
                                     82.0
                                     85.0
                                     76.3
                                     79.1
                                     75.0
                                                                      482011034
Texas
Harris
                                     81.0
                                     82.0
                                     76.8
                                     77.8
                                     72.0
                                                                      482011039
Texas
Harris
                                     82.0
                                     84.0
                                     78.2
                                     80.2
                                     72.0

Table V.C-3. Average and Maximum 2009-2013 and 2017 Baseline 8-Hour Ozone Design Values and 2012-2014 Design Values (ppb) at Projected Maintenance Sites in the Eastern U.S. Based on the CSAPR Methodology (Maintenance-Only Receptors)

Monitor ID
State
County
                        Average Design Value 2009-2013
                        Maximum Design Value 2009-2013
                           Average Design Value 2017
                           Maximum Design Value 2017
                            2012-2014 Design Value
                                                                       90010017
Connecticut
Fairfield
                                     80.3
                                     83.0
                                     75.8
                                     78.4
                                     82.0
                                                                      211110067
Kentucky
Jefferson
                                     82.0
                                     85.0
                                     75.8
                                     78.6
                                Incomplete Data
                                                                      211850004
Kentucky
Oldham
                                     82.0
                                     86.0
                                     73.7
                                     77.3
                                     74.0
                                                                      240053001
Maryland
Baltimore
                                     80.7
                                     84.0
                                     73.2
                                     76.2
                                     72.0
                                                                      260050003
Michigan
Allegan
                                     82.7
                                     86.0
                                     75.5
                                     78.5
                                     83.0
                                                                      261630019
Michigan
Wayne
                                     78.7
                                     81.0
                                     74.0
                                     76.2
                                     74.0
                                                                      340071001
New Jersey
Camden
                                     82.7
                                     87.0
                                     74.2
                                     78.1
                                     76.0
                                                                      340150002
New Jersey
Gloucester
                                     84.3
                                     87.0
                                     75.1
                                     77.5
                                     76.0
                                                                      340230011
New Jersey
Middlesex
                                     81.3
                                     85.0
                                     73.0
                                     76.3
                                     74.0
                                                                      340290006
New Jersey
Ocean
                                     82.0
                                     85.0
                                     73.9
                                     76.6
                                     75.0
                                                                      360810124
New York
Queens
                                     78.0
                                     80.0
                                     75.7
                                     77.6
                                     72.0
                                                                      420031005
Pennsylvania
Allegheny
                                     80.7
                                     82.0
                                     75.3
                                     76.5
                                     77.0
                                                                      421010024
Pennsylvania
Philadelphia
                                     83.3
                                     87.0
                                     75.1
                                     78.4
                                     75.0
                                                                      480850005
Texas
Collin
                                     82.7
                                     84.0
                                     74.9
                                     76.0
                                     78.0
                                                                      481130069
Texas
Dallas
                                     79.7
                                     84.0
                                     74.0
                                     78.0
                                     78.0
                                                                      481130075
Texas
Dallas
                                     82.0
                                     83.0
                                     75.8
                                     76.7
                                     77.0
                                                                      481211032
Texas
Denton
                                     82.7
                                     84.0
                                     75.1
                                     76.3
                                     79.0
                                                                      482010024
Texas
Harris
                                     80.3
                                     83.0
                                     75.9
                                     78.5
                                     72.0
                                                                      482010026
Texas
Harris
                                     77.3
                                     80.0
                                     73.5
                                     76.1
                                     67.0
                                                                      482010055
Texas
Harris
                                     81.3
                                     83.0
                                     75.4
                                     77.0
                                     75.0
                                                                      482011050
Texas
Harris
                                     78.3
                                     80.0
                                     74.6
                                     76.2
                                     72.0
                                                                      484390075
Texas
Tarrant
                                     82.0
                                     83.0
                                     75.5
                                     76.4
                                     79.0
                                                                      484393011
Texas
Tarrant
                                     80.7
                                     83.0
                                     74.5
                                     76.6
                                     75.0

D. Pollutant Transport from Upwind States
1. Air Quality Modeling to Quantify Upwind State Contributions
      This section documents the procedures the EPA used to quantify the impact of emissions from specific upwind states on 2017 8-hour design values for identified downwind nonattainment and maintenance receptors. The EPA used CAMx photochemical source apportionment modeling to quantify the impact of emissions in specific upwind states on downwind nonattainment and maintenance receptors for 8-hour ozone. CAMx employs enhanced source apportionment techniques that track the formation and transport of ozone from specific emissions sources and calculates the contribution of sources and precursors to ozone for individual receptor locations. The strength of the photochemical model source apportionment technique is that all modeled ozone at a given receptor location in the modeling domain is tracked back to specific sources of emissions and boundary conditions to fully characterize culpable sources.
      The EPA performed nationwide, state-level ozone source apportionment modeling using the CAMx Ozone Source Apportionment Technology/Anthropogenic Precursor Culpability Analysis (OSAT/APCA) technique to quantify the contribution of 2017 baseline NOX and VOC emissions from all sources in each state to projected 2017 ozone concentrations at air quality monitoring sites. In the source apportionment model run, we tracked the ozone formed from each of the following contribution categories (i.e., "tags"):
   * States  -  anthropogenic NOX and VOC emissions from each state tracked individually (emissions from all anthropogenic sectors in a given state were combined);
   * Biogenics  -  biogenic NOX and VOC emissions domain-wide (i.e., not by state);
   * Boundary Concentrations  -  concentrations transported into the modeling domain;
   * Tribes  -  the emissions from those tribal lands for which we have point source inventory data in the 2011 NEI (we did not model the contributions from individual tribes);
   * Canada and Mexico  -  anthropogenic emissions from sources in the portions of Canada and Mexico included in the modeling domain (we did not model the contributions from Canada and Mexico separately);
   * Fires  -  combined emissions from wild and prescribed fires; and
   * Offshore  -  combined emissions from offshore marine vessels and offshore drilling platforms.
      The CAMx OSAT/APCA model run was performed for the period May 1 through September 30 using the projected 2017 baseline emissions and 2011 meteorology for this time period. The hourly contributions from each tag were processed to obtain the 8-hour average contributions corresponding to the time period of the 8-hour daily maximum concentration on each day in the 2017 model simulation. This step was performed for those model grid cells containing monitoring sites in order to obtain 8-hour average contributions for each day at the location of each site. The model-predicted contributions were then applied in a relative sense to quantify the contributions to the 2017 average design value at each site. The resulting 2017 contributions from each tag to each monitoring site in the eastern and western U.S. along with additional details on the source apportionment modeling and the procedures for calculating contributions can be found in the AQM TSD. The EPA is seeking comment on the methodologies for calculating ozone contributions.
      The average contribution metric is intended to provide a reasonable representation of the contribution from individual states to the projected 2017 design value, based on modeled transport patterns and other meteorological conditions generally associated with modeled high ozone concentrations at the receptor. An average contribution metric constructed in this manner is beneficial since the magnitude of the contributions is directly related to the magnitude of the design value at each site.
	The largest contribution from each state in the East to 8-hour ozone nonattainment receptors in downwind states is provided in Table V.D-1. The largest contribution from each state in the East to 8-hour ozone maintenance-only receptors in downwind states is also provided in Table V.D-1.
Table V.D-1. Largest Contribution to Downwind 8-Hour Ozone Nonattainment and Maintenance Receptors for Each State in the Eastern U.S.
Upwind State
   Largest Downwind Contribution to Nonattainment Receptors for Ozone (ppb)
     Largest Downwind Contribution to Maintenance Receptors for Ozone (ppb
                                      AL
                                     0.79
                                     1.28
                                      AR
                                     0.98
                                     2.15
                                      CT
                                     0.00
                                     0.46
                                      DE
                                     0.37
                                     2.23
                                      DC
                                     0.06
                                     0.73
                                      FL
                                     0.54
                                     0.72
                                      GA
                                     0.47
                                     0.58
                                      IL
                                     17.48
                                     23.17
                                      IN
                                     6.24
                                     14.95
                                      IA
                                     0.61
                                     0.85
                                      KS
                                     0.80
                                     1.03
                                      KY
                                     0.75
                                     11.17
                                      LA
                                     3.09
                                     4.23
                                      ME
                                     0.00
                                     0.08
                                      MD
                                     2.07
                                     7.11
                                      MA
                                     0.10
                                     0.37
                                      MI
                                     2.69
                                     1.79
                                      MN
                                     0.40
                                     0.47
                                      MS
                                     0.78
                                     1.48
                                      MO
                                     1.63
                                     3.69
                                      NE
                                     0.24
                                     0.36
                                      NH
                                     0.02
                                     0.07
                                      NJ
                                     8.84
                                     12.38
                                      NY
                                     16.96
                                     17.21
                                      NC
                                     0.55
                                     0.93
                                      ND
                                     0.11
                                     0.28
                                      OH
                                     2.18
                                     7.92
                                      OK
                                     1.70
                                     2.46
                                      PA
                                     9.39
                                     15.93
                                      RI
                                     0.02
                                     0.08
                                      SC
                                     0.16
                                     0.21
                                      SD
                                     0.08
                                     0.12
                                      TN
                                     0.51
                                     1.67
                                      TX
                                     2.44
                                     2.95
                                      VT
                                     0.01
                                     0.05
                                      VA
                                     1.87
                                     5.29
                                      WV
                                     0.95
                                     3.11
                                      WI
                                     0.34
                                     2.59

2. Application of Screening Threshold
      The EPA then evaluated the magnitude of the contributions from each upwind state to downwind nonattainment and maintenance receptors. In this proposal, the EPA uses an air quality screening threshold to identify upwind states that contribute to downwind ozone concentrations in amounts sufficient to "link" them to these to downwind nonattainment and maintenance receptors.
      As discussed above in section III, the EPA is proposing to establish the air quality screening threshold calculated as one percent of the NAAQS. Specifically for this rule, we propose calculating an 8-hour ozone value for this air quality threshold of 0.75 ppb as the quantification of one percent of the 2008 ozone NAAQS.
      States in the East whose contributions to a specific receptor meet or exceed the screening threshold are considered linked to that receptor; those states' ozone contributions and emissions (and available emission reductions) are analyzed further, as described in section VI, to determine whether and what emissions reductions might be required from each state.
      States in the East whose contributions are below the threshold are not included in the proposed rule and are considered to make insignificant contributions to projected downwind air quality problems. However, for eastern states for which the EPA is not proposing FIPs in this action, the EPA notes that updates to the modeling for the final rule could change the analysis as to which states have contributions that meet or exceed the screening threshold. In the event that air quality modeling conducted for the final rule demonstrates that states that contribute amounts below the threshold in the proposal are projected to contribute amounts greater than or equal to the threshold in the final rule modeling, the EPA instead proposes to finalize revised budgets (presented with this rulemaking for comment) for whichever of those states may be identified as linked to such air quality problems. The EPA has calculated emissions budgets for all eastern states that we are proposing to apply to those states if, and only if, the final rule air quality modeling identifies a linkage as just described. These budgets are available in the Ozone Transport Policy Analysis TSD.
      Based on the maximum downwind contributions in Table V.D-1, the following states contribute at or above the 0.75 ppb threshold to downwind nonattainment receptors: Alabama, Arkansas, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maryland, Michigan, Mississippi, Missouri, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Texas, Virginia, and West Virginia. Based on the maximum downwind contributions in Table V.D-1, the following states contribute at or above the 0.75 ppb threshold to downwind maintenance-only receptors: Alabama, Arkansas, Delaware, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Michigan, Mississippi, Missouri, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas, Virginia, West Virginia, and Wisconsin. The linkages between each upwind state and downwind nonattainment receptors and maintenance-only receptors in the eastern U.S. are provided in Table V.D-2 and Table V.D-3, respectively.
Table V.D-2. Linkages Between Each Upwind State and Downwind Nonattainment Receptors in the Eastern U.S.

                                 Upwind State
                       Downwind Nonattainment Receptors
                                      AL
Tarrant Co, TX (484392003)

                                      AR
Brazoria Co, TX (480391004)
Tarrant Co, TX (484392003)
Tarrant Co, TX (484393009)
                                      IL
Brazoria Co, TX (480391004)
Sheboygan Co, WI (551170006)

                                      IN
Fairfield Co, CT (90013007)
Fairfield Co, CT (90019003)
Sheboygan Co, WI (551170006)
                                      KS
Sheboygan Co, WI (551170006)

                                      KY
Sheboygan Co, WI (551170006)

                                      LA
Brazoria Co, TX (480391004)
Denton Co, TX (481210034)
Tarrant Co, TX (484392003)

Tarrant Co, TX (484393009)
Sheboygan Co, WI (551170006)

                                      MD
Fairfield Co, CT (90013007)
Fairfield Co, CT (90019003)
New Haven Co, CT (90099002)
                                      MI
Fairfield Co, CT (90013007)
Fairfield Co, CT (90019003)
New Haven Co, CT (90099002)

Sheboygan Co, WI (551170006)

                                      MS
Brazoria Co, TX (480391004)

                                      MO
Brazoria Co, TX (480391004)
Sheboygan Co, WI (551170006)

                                      NJ
Fairfield Co, CT (90013007)
Fairfield Co, CT (90019003)
New Haven Co, CT (90099002)
                                      NY
Fairfield Co, CT (90013007)
Fairfield Co, CT (90019003)
New Haven Co, CT (90099002)
                                      OH
Fairfield Co, CT (90013007)
Fairfield Co, CT (90019003)
New Haven Co, CT (90099002)

Sheboygan Co, WI (551170006)

                                      OK
Denton Co, TX (481210034)
Tarrant Co, TX (484392003)
Tarrant Co, TX (484393009)

Sheboygan Co, WI (551170006)

                                      PA
Fairfield Co, CT (90013007)
Fairfield Co, CT (90019003)
New Haven Co, CT (90099002)
                                      TX
Sheboygan Co, WI (551170006)

                                      VA
Fairfield Co, CT (90013007)
Fairfield Co, CT (90019003)
New Haven Co, CT (90099002)
                                      WV
Fairfield Co, CT (90013007)
Fairfield Co, CT (90019003)

Table V.D-3. Linkages Between Each Upwind States and Downwind Maintenance-Only Receptors in the Eastern U.S.

                                 Upwind State
                       Downwind Nonattainment Receptors
                                      AL
Hamilton Co, OH (390610006)
Harris Co, TX (482010055)

                                      AR
Oldham Co, KY (211850004)
Allegan Co, MI (260050003)
Dallas Co, TX (481130069)

Dallas Co, TX (481130075)
Harris Co, TX (482010026)
Harris Co, TX (482010055)

Harris Co, TX (482011039)
Harris Co, TX (482011050)
Tarrant Co, TX (484390075)

Tarrant Co, TX (484393011)

                                      DE
Camden Co, NJ (340071001)
Gloucester Co, NJ (340150002)
Ocean Co, NJ (340290006)

Philadelphia Co, PA (421010024)

                                      IL
Jefferson Co, KY (211110067)
Oldham Co, KY (211850004)
Allegan Co, MI (260050003)

Wayne Co, MI (261630019)
Camden Co, NJ (340071001)
Gloucester Co, NJ (340150002)

Ocean Co, NJ (340290006)
Queens Co, NY (360810124)
Suffolk Co, NY (361030002)

Hamilton Co, OH (390610006)
Allegheny Co, PA (420031005)
Harris Co, TX (482010026)

Harris Co, TX (482011039)

                                      IN
Jefferson Co, KY (211110067)
Oldham Co, KY (211850004)
Baltimore Co, MD (240053001)

Harford Co, MD (240251001)
Allegan Co, MI (260050003)
Wayne Co, MI (261630019)

Camden Co, NJ (340071001)
Gloucester Co, NJ (340150002)
Middlesex Co, NJ (340230011)

Ocean Co, NJ (340290006)
Queens Co, NY (360810124)
Richmond Co, NY (360850067)

Suffolk Co, NY (361030002)
Hamilton Co, OH (390610006)
Allegheny Co, PA (420031005)

Philadelphia Co, PA (421010024)

                                      IA
Allegan Co, MI (260050003)

                                      KS
Allegan Co, MI (260050003)
Tarrant Co, TX (484390075)
Tarrant Co, TX (484393011)
                                      KY
Baltimore Co, MD (240053001)
Harford Co, MD (240251001)
Camden Co, NJ (340071001)

Gloucester Co, NJ (340150002)
Middlesex Co, NJ (340230011)
Ocean Co, NJ (340290006)

Richmond Co, NY (360850067)
Hamilton Co, OH (390610006)
Allegheny Co, PA (420031005)

Philadelphia Co, PA (421010024)

                                      LA
Collin Co, TX (480850005)
Dallas Co, TX (481130069)
Dallas Co, TX (481130075)

Denton Co, TX (481211032)
Harris Co, TX (482010024)
Harris Co, TX (482010026)

Harris Co, TX (482010055)
Harris Co, TX (482011034)
Harris Co, TX (482011039)

Harris Co, TX (482011050)
Tarrant Co, TX (484390075)
Tarrant Co, TX (484393011)
                                      MD
Fairfield Co, CT (90010017)
Gloucester Co, NJ (340150002)
Middlesex Co, NJ (340230011)

Ocean Co, NJ (340290006)
Queens Co, NY (360810124)
Richmond Co, NY (360850067)

Suffolk Co, NY (361030002)
Philadelphia Co, PA (421010024)

                                      MI
Fairfield Co, CT (90010017)
Jefferson Co, KY (211110067)
Oldham Co, KY (211850004)

Harford Co, MD (240251001)
Camden Co, NJ (340071001)
Gloucester Co, NJ (340150002)

Ocean Co, NJ (340290006)
Queens Co, NY (360810124)
Richmond Co, NY (360850067)

Suffolk Co, NY (361030002)
Hamilton Co, OH (390610006)
Allegheny Co, PA (420031005)
                                      MS
Harris Co, TX (482010055)
Harris Co, TX (482011039)

                                      MO
Oldham Co, KY (211850004)
Allegan Co, MI (260050003)
Camden Co, NJ (340071001)

Hamilton Co, OH (390610006)
Harris Co, TX (482010026)
Harris Co, TX (482010055)

Harris Co, TX (482011039)
Harris Co, TX (482011050)

                                      NJ
Fairfield Co, CT (90010017)
Queens Co, NY (360810124)
Richmond Co, NY (360850067)

Suffolk Co, NY (361030002)
Philadelphia Co, PA (421010024)

                                      NY
Fairfield Co, CT (90010017)
Camden Co, NJ (340071001)
Gloucester Co, NJ (340150002)

Middlesex Co, NJ (340230011)
Ocean Co, NJ (340290006)

                                      NC
Baltimore Co, MD (240053001)

                                      OH
Fairfield Co, CT (90010017)
Jefferson Co, KY (211110067)
Oldham Co, KY (211850004)

Baltimore Co, MD (240053001)
Harford Co, MD (240251001)
Wayne Co, MI (261630019)

Camden Co, NJ (340071001)
Gloucester Co, NJ (340150002)
Middlesex Co, NJ (340230011)

Ocean Co, NJ (340290006)
Queens Co, NY (360810124)
Richmond Co, NY (360850067)

Suffolk Co, NY (361030002)
Allegheny Co, PA (420031005)
Philadelphia Co, PA (421010024)
                                      OK
Allegan Co, MI (260050003)
Hamilton Co, OH (390610006)
Dallas Co, TX (481130069)

Dallas Co, TX (481130075)
Denton Co, TX (481211032)
Harris Co, TX (482010026)

Harris Co, TX (482011034)
Harris Co, TX (482011039)
Tarrant Co, TX (484390075)

Tarrant Co, TX (484393011)

                                      PA
Fairfield Co, CT (90010017)
Baltimore Co, MD (240053001)
Harford Co, MD (240251001)

Camden Co, NJ (340071001)
Gloucester Co, NJ (340150002)
Middlesex Co, NJ (340230011)

Ocean Co, NJ (340290006)
Queens Co, NY (360810124)
Richmond Co, NY (360850067)

Suffolk Co, NY (361030002)

                                      TN
Hamilton Co, OH (390610006)
Philadelphia Co, PA (421010024)

                                      TX
Baltimore Co, MD (240053001)
Harford Co, MD (240251001)
Allegan Co, MI (260050003)

Camden Co, NJ (340071001)
Gloucester Co, NJ (340150002)
Ocean Co, NJ (340290006)

Queens Co, NY (360810124)
Richmond Co, NY (360850067)
Suffolk Co, NY (361030002)

Hamilton Co, OH (390610006)
Allegheny Co, PA (420031005)
Philadelphia Co, PA (421010024)
                                      VA
Fairfield Co, CT (90010017)
Baltimore Co, MD (240053001)
Harford Co, MD (240251001)

Gloucester Co, NJ (340150002)
Middlesex Co, NJ (340230011)
Ocean Co, NJ (340290006)

Queens Co, NY (360810124)
Richmond Co, NY (360850067)
Suffolk Co, NY (361030002)

Philadelphia Co, PA (421010024)

                                      WV
Baltimore Co, MD (240053001)
Harford Co, MD (240251001)
Camden Co, NJ (340071001)

Gloucester Co, NJ (340150002)
Middlesex Co, NJ (340230011)
Ocean Co, NJ (340290006)

Queens Co, NY (360810124)
Richmond Co, NY (360850067)
Suffolk Co, NY (361030002)

Hamilton Co, OH (390610006)
Allegheny Co, PA (420031005)
Philadelphia Co, PA (421010024)
                                      WI
Allegan Co, MI (260050003)
Wayne Co, MI (261630019)

      As discussed previously, after the receptor and contribution analyses for this proposal were underway, the EPA released an updated IPM base case, version 5.15, and the final CPP. In order to reflect all on-the-books policies as well as the most current power sector modeling data, the EPA performed an assessment to reflect inclusion of IPM 5.15 with the CPP in an "adjusted" base case for this proposal. All references below to the "adjusted base case" refer to the 2017 air quality modeling base case which has been adjusted to account for the revised IPM 5.15 with CPP emissions. This assessment method relied on the EPA's air quality modeling contribution data as well as projected ozone concentrations from an illustrative EGU NOX mitigation scenario. For more information about these methods, refer to the Ozone Transport Policy Analysis Technical Support Document.
      This assessment shows that two receptors -- Hamilton County Ohio (390610006) and Richmond County New York (360850067) - -  that were projected to have average design values exceeding the NAAQS in the modeled 2017 baseline, are expected to have average design values below the NAAQS with the adjusted base case. However, these receptors are still expected to have maximum design values exceeding the NAAQS with the adjusted base case. Because both of these receptors are also considered maintenance receptors for the purposes of this proposal, their status as identified air quality concerns and the status of states linked to these receptors is unchanged by the adjusted base case.
      This assessment also shows that four receptors  -  Allegheny County Pennsylvania (420031005), Collin County Texas (480850005), Wayne County Michigan (261630019), and Middlesex County New Jersey (340230011) - -  that were projected to have maximum design values exceeding the NAAQS in the modeled base case, are expected to have maximum design values below the NAAQS with the adjusted base case. With the adjusted base case, these sites would not be considered nonattainment or maintenance receptors for the purposes of this proposal. However, because no state is linked solely to any one of these sites, changing the status of these receptors does not impact the scope of states linked to downwind nonattainment or maintenance receptors for this proposal.
      In addition to evaluating the status of downwind receptors identified for this proposal, the EPA evaluated whether the adjusted base case would reduce ozone contributions from upwind states to the extent that a previously linked state would have a maximum contribution less than the 1% threshold. This assessment shows that in the adjusted base case, all states are expected to remain linked (i.e., contribute greater than or equal to 1% of the NAAQS) to at least one downwind nonattainment or maintenance receptor. Therefore, using the adjusted base case for this proposal does not impact the scope of states linked to downwind nonattainment or maintenance receptors relative to the modeled base case.
      The EPA seeks comment on this analysis, but notes that for the final rule, the EPA intends to rely on full air quality modeling of the adjusted base case to identify nonattainment and maintenance receptors and to inform the analysis of interstate ozone transport for the 2008 ozone NAAQS.
      The analyses that EPA uses in section VI to quantify EGU NOX ozone-season emissions budgets for this proposal rely on the adjusted base case.

VI. Quantifying Upwind-State EGU NOX Reduction Potential to Reduce Interstate Ozone Transport for the 2008 NAAQS
A. Introduction
      This section describes the EPA's proposed quantification of near-term EGU NOX reductions that are necessary to fulfill (at least in part) the Clean Air Act requirement to address interstate ozone transport for the 2008 NAAQS. This section also describes the EPA's proposal to translate these reductions into EGU NOX ozone-season emissions budgets. Section VII describes the EPA's proposal to implement these proposed emissions budgets via updates to the existing CSAPR NOX ozone-season trading program.
      As described in section V, the EPA separately identified nonattainment receptors and maintenance receptors. The EPA proposes to apply a single approach for quantifying an upwind state's ozone transport obligation to both nonattainment and maintenance receptors. It is reasonable to apply the same approach to quantify upwind-state reduction requirements with respect to both nonattainment and maintenance because the structure of the problems is the same  --  emissions from sources in upwind states contributing to downwind ozone concentrations that put the downwind receptor at risk of nonattainment with respect to the EPA's clean air standards. Moreover, as all nonattainment receptors are also maintenance receptors because the maximum design value will always be equal to or exceed the average design value, it is reasonable to control all sites consistent with the level of control necessary to reduce maintenance concerns.
      As described in section III of this preamble, due to the impending July 2018 moderate area attainment date, the EPA is proposing, as a first step, to quantify near-term EGU NOX ozone-season emission reductions to reduce interstate ozone transport for the 2008 ozone NAAQS. For this section, this means that the EPA is proposing to quantify ozone season EGU NOX reductions achievable for the 2017 ozone season (i.e., the last full ozone season prior to the July 2018 attainment date).
      The EPA's assessment of upwind state obligations in this proposal reflects application of a multi-factor test that considers cost, available emission reductions, and air quality. This is the same multi-factor test used in the original CSAPR. This multi-factor test considers increasing levels of uniform control stringency, where each level is represented by cost, to determine the appropriate magnitude of pollution reduction that would reduce the impacts of interstate transport on downwind states and to apportion that reduction responsibility among collectively-contributing upwind states. This approach to quantifying upwind state emission reduction obligations was reviewed by the Supreme Court in EPA v. EME Homer City Generation, which held that using such an approach to apportion reduction responsibilities among upwind states that are collectively responsible for downwind air quality impacts "is an efficient and equitable solution to the allocation problem the Good Neighbor Provision requires the Agency to address." 134 S.Ct. at 1607.
There are three steps in developing and applying the multi-factor test to quantify upwind state emission reductions as to the 2008 ozone NAAQS: (1) identify NOX mitigation strategies, focusing on those that can be in place for the 2017 ozone season; (2) develop uniform EGU NOX cost thresholds based on these NOx mitigation strategies; (3) assess EGU NOX mitigation potential that is achievable for 2017 and assess corresponding air quality improvements resulting from the application of each uniform cost threshold, including to check for over-control. This multi-factor evaluation informs the EPA's determination of appropriate ozone season EGU NOX reductions necessary to reduce significant contribution to nonattainment and interference with maintenance of the 2008 ozone NAAQS for the proposed 2017 compliance year. These steps are discussed in further detail in the following sections.
This proposal evaluates a range of uniform EGU NOX costs from $500 per ton to $10,000 per ton. This range, and the intermediate uniform NOX cost thresholds evaluated within that range, were selected based on the cost thresholds at which various EGU NOX control technologies are widely available, the use of certain EGU NOX cost thresholds in previous rules to address ozone transport, and EGU NOX cost thresholds incorporated into state requirements to address ozone nonattainment.
The EPA evaluated the emission reduction potential in each upwind state at each uniform NOX cost threshold using IPM. In this case, the EPA limited IPM's evaluation of NOX mitigation strategies to those that can be implemented for the 2017 ozone season, which is the proposed compliance timing for this rule, as described in section VI.B below.
B. NOX Mitigation Strategies
The following sub-sections describe the EPA's assessment of EGU and non-EGU point source NOX mitigation strategies. For more details on these assessments, refer to the EGU NOX Mitigation Strategies TSD and the Update to Non-EGU Emission Reductions Cost and Potential for States with Potentially Significant Contributions under the 2008 Ozone Standard TSD in the docket for this proposed rule.
1. EGU NOX Mitigation Strategies
    In developing this proposed rule, the EPA considered all widely used EGU NOX control strategies: fully operating existing Selective Catalytic Reduction (SCR) and Selective Non-Catalytic Reduction (SNCR)  -  including optimizing NOX removal by existing, operational SCRs and SNCRs and turning on and optimizing existing idled SCRs and SNCRs; installation of (or upgrading to) state-of-the-art NOX combustion controls; shifting generation to units with lower NOX emission rates within the same state; and installing new SCRs and SNCRs.
    For the reasons explained below, the EPA determined that the power sector could implement all of these NOX mitigation strategies, except installation of new SCRs or SNCRs, for the 2017 ozone season, assuming this proposal is finalized in the summer of 2016. As to the installation of new SCRs or SNCRs, the amount of time from contract award through commissioning for retrofit with new SCR or SNCR exceeds 18 and 12 months, respectively. For both technologies, conceptual design, permitting, financing, and bid review require additional time. It would therefore not be feasible to retrofit new SCR or SNCR to achieve EGU NOX reductions in the 2017 ozone season. See EGU NOX Mitigation Strategies TSD for discussion of feasibility of EGU NOX controls for the 2017 ozone season. Therefore, the EPA analyzed the remaining strategies for purposes of quantifying upwind state obligations in this rule. Exclusion of new SCR and SNCR installation from this analysis reflects a determination only that these strategies are infeasible by 2017, not a determination that they are infeasible or inappropriate for consideration of cost-effective NOX reduction potential over a longer timeframe. The EPA requests comment on what EGU NOX mitigation strategies are feasible for the 2017 ozone season.
               a.          Fully operating existing SCRs and SNCRs
Fully operating existing SCR and SNCRs can significantly reduce EGU NOX emissions quickly, using investments that have already been made. SCRs can achieve up to 90 percent reduction in EGU NOX (with sufficient installed catalyst), while SNCRs can achieve 20-30 percent reduction in EGU NOX, beyond the reductions from combustion controls. These controls are in widespread use across the U.S. power sector. In the east, approximately 64 percent of coal-fired EGU capacity and 75 percent of natural gas combined cycle (NGCC) EGU capacity is equipped with SCR or SNCR. Recent power sector data reveal that some SCR and SNCR controls are being underused. In some cases, controls are not fully operating (i.e., the controls could be operated at a higher NOX removal rate). In other cases, controls have been idled for years. Fully operating existing SCR and SNCR would be a cost-effective and readily available approach for EGUs to reduce NOX emissions and the EPA evaluated this NOX mitigation strategy in quantifying EGU NOX obligations for this proposal.
For existing SCRs and SNCRs that are operating to some extent, but not at their full pollution control capability, the EPA's analysis determined that $500 per ton represents the costs reflective of fully operating these systems. Because the SCR or SNCR is already installed and is at least to some extent operating, the EPA assumes that additional reagent (i.e., ammonia or urea) is the only significant cost required for full operation. We observe that urea can cost on the order of $300 per metric ton. The cost for anhydrous ammonia is around $750 per ton. In our assessment, we assume that a 50 percent solution is used in removing an equivalent amount of NOX. Thus, we estimate that sufficient reagent could be purchased at a cost of $500 per ton of NOX removed to achieve full operation for most SCRs and SNCRs. For more details on this assessment, refer to the EGU NOX Mitigation Strategies TSD in the docket for this proposed rule. The proposal seeks comment on this assessment.
The operational difference between not fully operating and fully operating existing SCRs and SNCRs is increasing reagent (i.e., ammonia or urea) flow rate and ensuring sufficient reagent exists to sustain higher flow operations. Therefore, increasing NOX removal from these controls can be implemented by procuring more reagent. Stocking-up additional reagent for sustaining increased NOX removal could be done in a one or two weeks.
      For existing SCRs and SNCRs that have been idled for years, unit operators may need to restart payment of some fixed and variable costs associated with that control. Fixed and variable costs include labor, maintenance and repair, reagent, parasitic load, and ammonia or urea. As further detailed in the EGU NOX Mitigation Strategies TSD, which is found in the docket for this proposed rule, the EPA performed an in-depth cost assessment for all coal-fired units with SCRs, finding that 90 percent of the units had total SCR operation costs of $1,300 per ton of NOX removed, or less.
Based on this assessment, the EPA proposes that turning on and fully operating idled SCRs is widely available at a uniform cost of $1,300 per ton of NOX removed. For more details on this assessment, refer to the EGU NOX Mitigation Strategies TSD in the docket for this proposed rule. The proposal seeks comment on this assessment.
The EPA performed a similar assessment for fully operating existing idled SNCR systems, finding that the majority of the total fixed and variable operating cost for SNCR is related to the cost of the reagent used (e.g., ammonia or urea) and that the resulting cost per ton of NOX reduction is sensitive to the NOX rate of the unit prior to SNCR operation. Based on the results of this analysis, and in order to represent a broad range of unit-level NOX rates before SNCR operation, the EPA proposes that turning on and fully operating idled SNCRs is widely available at a uniform cost of $3,400 per ton of NOX removed. For more details on this assessment, refer to the EGU NOX Mitigation Strategies TSD in the docket for this proposed rule. The proposal seeks comment on this assessment.
The EPA also evaluated the feasibility of turning on idled SCR and SNCR for the 2017 ozone season. Based on past practice and the possible effort to restart the controls (e.g., stockpiling reagent, bringing the system out of protective lay-up, performing inspections, etc.), returning these idled controls to operation should be available in equal to or less than 3 months. The proposal seeks comment on this assessment.
               b.          State-of-the-art NOX combustion controls
      State-of-the-art combustion controls such as low-NOX burners (LNB) and/or over-fire air (OFA) are cost-effective, can be installed quickly, and can significantly reduce EGU NOX emissions. Ninety-nine percent of coal-fired EGU capacity in the East is equipped with some form of combustion control. Combustion controls alone can achieve NOX emission rates of 0.15 to 0.50 lb/mmBtu. Once installed, combustion controls reduce NOX emissions at all times of EGU operation. State-of-the-art combustion controls would be a cost-effective, timely, and readily available approach for EGUs to reduce NOX emissions and the EPA included this NOX mitigation strategy in quantifying EGU NOX reductions for this proposal.
      The cost of state-of-the-art combustion controls per ton of NOX reduced is dependent on the combustion control type and unit type. We estimate the cost per ton of state-of-the-art combustion controls to be $500 per ton to $1,200 per ton of NOX removed. To be conservative, the EPA proposes that installation of (or upgrading to) state-of-the-art NOX combustion controls is widely available at $1,300 per ton of NOX removed.
      As described in CSAPR the EPA has observed that upgrade, replacement, or installation of combustion controls has been demonstrated to be achievable within 6 months. The EPA revisited this analysis with data specific to this proposal and proposes that 6 months remains feasible for this EGU NOX mitigation strategy. The EPA proposes that this will be feasible for the 2017 ozone season.
      For more details on this assessment, refer to the EGU NOX Mitigation Strategies TSD in the docket for this proposed rule. The proposal seeks comment on this assessment.
               c.          Shifting generation to lower NOX-emitting EGUs
 	Shifting generation to lower NOX-emitting EGUs, similar to operating existing post-combustion controls, uses investments that have already been made, can be done quickly, and can significantly reduce EGU NOX emissions.
 	Since CSAPR was promulgated, electricity generation has trended toward lower NOX-emitting generation due to market conditions (e.g., low natural gas prices) and state and federal environmental policies. For example, new NGCC facilities, which represented 45% of new 2014 capacity, can achieve NOX emission rates of 0.0095 lb/mmBtu, compared to existing coal steam facilities, which emitted at an average rate across the 23 states included in this proposal of 0.18 lbs/mmbBtu of NOX in 2014. This substantial difference in NOX emission performance between existing coal steam and new NGCC generation is due both to higher nitrogen content in coal compared to natural gas, as well as to the substantially lower generating efficiency of steam combustion technology compared to combined cycle combustion technology. Shifting generation to lower NOX-emitting EGUs would be a cost-effective, timely, and readily available approach for EGUs to reduce NOX emissions and the EPA included this NOX mitigation strategy in quantifying EGU NOX obligations for this proposal.
     Shifting generation to lower NOX-emitting EGUs occurs on a continuum in response to economic factors such as fuel costs and uniform NOX cost thresholds, including those evaluated for this proposal (i.e., relatively lower uniform NOX cost thresholds incentivize relatively fewer EGU NOX reductions resulting from shifting generation, while relatively higher uniform NOX cost thresholds encourage more EGU NOX reductions driven by shifting generation). As a result, the EPA quantified reduction potential from this EGU NOX mitigation strategy at each cost level identified that represents the availability of other pollution control measures evaluated in our assessment of uniform NOX cost thresholds described in section VI.C.
    The EPA limited shifting generation to units with lower NOX emission rates within the same state due to the near-term 2017 implementation timing for this proposed rule.  The EPA seeks comment on this assessment and on this limitation in quantifying EGU NOX reduction potential for the 2017 ozone season.
2. Non-EGU NOX Mitigation Strategies
      The EPA is not proposing to address non-EGU emission reductions in its efforts to reduce interstate ozone transport for the 2008 ozone NAAQS at this time. Compared to EGUs, there are relatively more non-EGU point sources and these sources on average are smaller than EGUs. The implication of these fleet characteristics is that there are more individual sources to control and there are relatively fewer emission reductions available from each source. Given the proposed 2017 implementation timing for this rule, we are uncertain that significant aggregate NOX mitigation is achievable from non-EGU point sources for 2017. Moreover, there is greater uncertainty in the EPA's assessment of non-EGU point-source NOX mitigation potential (see below). The EPA requests comment on these issues, including how non-EGU reductions should be addressed and considered in fulfilling upwind states' good neighbor obligations under the 2008 ozone standard in the future, as the control of non-EGUs may be a necessary part of addressing states' full transport obligation. States can always choose to reduce non-EGU emissions via good neighbor SIPs.
    The EPA has evaluated the potential for ozone season NOX reductions from non-EGU sources. A detailed discussion of this assessment is provided in the Non-EGU NOX Mitigation Potential TSD, located in the docket for this proposed rule. This TSD discusses non-EGU source category emissions, EPA tools for estimating emission reductions from non-EGU categories, and efforts, to date, to review and refine our estimates for certain states. In addition, the TSD contains brief discussions of available controls, costs, and potential emission reductions for a few specific source categories. The EPA views this non-EGU assessment as an initial step in future efforts to evaluate non-EGU categories that may be necessary to fully quantify upwind states' significant contribution to nonattainment and interference with maintenance. The EPA seeks comment on this non-EGU NOX mitigation assessment and the availability of non-EGU NOX emission reductions to mitigate interstate ozone transport.
C. Uniform EGU Cost Thresholds for Assessment
      As discussed above, the multi-factor test used here considers increasing levels of uniform control stringency, where each level is represented by cost, in combination with consideration of NOX reduction potential and corresponding air quality improvements. To determine which cost thresholds to use to assess upwind state NOX mitigation potential, the EPA evaluated EGU NOX control costs that represent the thresholds at which various control technologies are widely available (described previously in section VI.B), the use of certain cost thresholds in previous rules to address ozone transport, and cost thresholds incorporated into state requirements to address ozone nonattainment.
      The EPA began by determining the appropriate range of costs to evaluate. The lower end of the range is informed by a confluence of considerations. In CSAPR, $500 per ton was the EGU NOX cost threshold relied upon to partially address ozone transport for the less stringent 1997 standard. It is also the lowest marginal cost where EPA expects NOX reduction to be cost effective, based on our assessment of EGU NOX mitigation strategies (see section B). Specifically, the cost of this approach to NOX reduction is the marginal cost of running currently operating SCR and SNCR systems at higher levels of NOX removal than they are currently achieving. The EPA has not identified a discrete NOX pollution control measure that would achieve sufficient emission reductions to address relevant air quality impacts at an estimated cost of less than $500 per ton; as a result, the EPA has not included a representation of such a cost level in this proposal's analyses.
      The EPA then evaluated EGU NOX cost thresholds to determine an appropriate upper bound for our assessment. The EPA identified $10,000 per ton as an upper bound, exceeding the costs of operating existing or installing new EGU NOX controls.
      The EPA seeks comment on whether $500 per ton is an appropriate minimum and $10,000 per ton is an appropriate maximum uniform cost threshold to evaluate for the purpose of quantifying EGU NOX reductions to reduce interstate ozone transport for the 2008 ozone NAAQS.
      The EPA then determined appropriate EGU NOX cost thresholds to evaluate within the range of $500 per ton to $10,000 per ton. As described above, these cost thresholds are informed by our assessment of the costs at which EGU NOX control strategies are widely available. While the EPA could evaluate additional cost thresholds in between those selected, this would not yield meaningful insights as to NOX reduction potential. The EPA has identified cost thresholds where control technologies are widely available and thereby where the most significant incremental emission reduction potential is expected. Analyzing costs between these cost thresholds is not expected to reveal significant incremental emission reduction potential that isn't already anticipated at the analyzed cost thresholds. Table VI.X lists the EGU NOX cost thresholds evaluated and the NOX reduction strategy or policy used to identify each cost threshold.
Table VI.X
EGU NOX Cost Threshold

$500/ton
CSAPR ozone season NOX cost threshold; fully operating post-combustion controls that are already running.
$1,300/ton
Widespread availability of restarting idled SCRs and state of the art combustion controls
$3,400/ton
NOX SIP Call ozone season NOX cost threshold, adjusted to 2014$; Widespread availability of restarting idled SNCRs
$5,000/ton
Widespread availability of new SCRs
$6,400/ton
Widespread availability of new SNCRs
$10,000/ton
Upper bound

      The EPA proposes that this range and selection of interim uniform cost thresholds are appropriate to evaluate potential EGU NOX reduction obligations to address interstate ozone transport for the 2008 ozone NAAQS. Because these cost thresholds are linked to costs at which EGU NOX mitigation strategies become widely available in each state, the cost thresholds represent the break points at which the most significant step-changes in EGU NOX mitigation are expected. The EPA seeks comment on the appropriateness of evaluating these uniform cost thresholds for the purpose of quantifying EGU NOX reductions to reduce interstate ozone transport for the 2008 ozone NAAQS.
D. Assessing Cost, EGU NOX Reductions, and Air Quality
    	The EPA analyzed ozone season NOX emission reductions available from the power sector in each state using IPM. The agency analyzed levels of uniform control stringency, where each level is represented by uniform EGU NOX cost thresholds listed in Table VI.X above and repeated here: $500 per ton; $1,300 per ton; $3,400 per ton; $5,000 per ton; $6,400 per ton; and $10,000 per ton. The EPA limited IPM's NOX mitigation strategies to those that could be implemented for 2017, as described in section VI.B.
      The analysis applied these uniform EGU NOX cost thresholds to EGUs in the 48 contiguous United States and the District of Columbia, starting in 2017. The analysis covered EGUs with a capacity (electrical output) greater than 25 MW to make the analysis similar to previous analyses done for interstate transport purposes. The EGU Emission Reduction Cost Analysis TSD, which is in the docket for this proposed rule, provides further details of EPA's analysis of ozone season NOX emission reductions occurring at the representative EGU NOx cost thresholds analyzed for the 2017 ozone season.
      Table VI.E-2 shows the 2017 baseline EGU emissions and ozone season NOX reduction potential in each state corresponding to the uniform cost levels.
Table VI.E-2. EGU Ozone Season NOX Emission Reductions (Tons)
State
2017 Emissions (short tons)
Reduction Potential (short tons) at Various Representative Marginal Costs per Ton (in 2011$)

Base Case
$500/ton
$1,300/ton
$3,400/ton
Alabama
13,289
   1,729
   3,582
   3,670
Arkansas
6,224
     13
    104
    859
Illinois
10,021
    395
    472
    546
Indiana
41,748
   6,611
  12,173
  12,989
Iowa
7,911
    186
    423
    717
Kansas
11,332
    428
    438
    465
Kentucky
27,141
   3,608
  11,896
  12,382
Louisiana
10,897
     64
    117
    400
Maryland
6,470
   1,028
   1,026
   1,164
Michigan
20,049
    403
   3,033
   3,528
Mississippi
7,871
     82
    297
    893
Missouri
17,050
    934
    996
   1,152
New Jersey
3,302
    370
    372
    378
New York
4,948
    115
    284
    359
North Carolina
14,435
   1,922
   1,922
   3,526
Ohio
27,795
   5,746
   9,646
   9,666
Oklahoma
19,593
    703
   2,170
   3,169
Pennsylvania
41,533
   2,210
  26,759
  26,791
Tennessee
5,554
     74
    113
    146
Texas
58,199
    685
   3,610
   5,810
Virginia
7,196
    423
    539
   1,587
West Virginia
25,384
    592
  10,908
  12,014
Wisconsin
5,257
      5
     36
    107
Total
393,198
  28,325
  90,916
 102,318

Table VI.E-2 (continued). EGU Ozone Season NOX Emission Reductions (Tons)
State
Reduction Potential (short tons) at Various Representative Marginal Costs per Ton (in 2011$)

$5,000/ton
$6,400/ton
$10,000/ton
Alabama
                                                                          4,780
                                                                          5,418
                                                                          5,840
Arkansas
                                                                          1,147
                                                                          1,242
                                                                          1,935
Illinois
                                                                            622
                                                                            640
                                                                            761
Indiana
                                                                         13,770
                                                                         13,437
                                                                         17,109
Iowa
                                                                            717
                                                                            717
                                                                          1,317
Kansas
                                                                            677
                                                                            838
                                                                          1,150
Kentucky
                                                                         12,473
                                                                         13,456
                                                                         14,503
Louisiana
                                                                            461
                                                                            467
                                                                            706
Maryland
                                                                          1,176
                                                                          1,369
                                                                          1,369
Michigan
                                                                          3,756
                                                                          3,889
                                                                          4,411
Mississippi
                                                                          1,165
                                                                          1,479
                                                                          2,208
Missouri
                                                                          1,298
                                                                          1,930
                                                                          2,775
New Jersey
                                                                            381
                                                                            384
                                                                            465
New York
                                                                            370
                                                                            661
                                                                            906
North Carolina
                                                                          3,626
                                                                          4,415
                                                                          4,643
Ohio
                                                                          9,773
                                                                         10,078
                                                                         10,231
Oklahoma
                                                                          3,821
                                                                          5,702
                                                                          6,609
Pennsylvania
                                                                         26,913
                                                                         26,932
                                                                         27,091
Tennessee
                                                                            224
                                                                            241
                                                                            285
Texas
                                                                          6,940
                                                                          7,772
                                                                          8,380
Virginia
                                                                          3,104
                                                                          3,560
                                                                          3,610
West Virginia
                                                                         12,211
                                                                         12,243
                                                                         12,243
Wisconsin
                                                                            131
                                                                            276
                                                                            618
Total
                                                                        109,535
                                                                        117,145
                                                                        129,166

	Next, the EPA performed a combined multi-factor assessment of costs (i.e., the uniform cost thresholds evaluated), EGU NOX reductions (i.e., the reductions in Table 6.E-2), and corresponding improvements in downwind ozone concentrations. For this assessment, the EPA used simplifying assumptions regarding the relationship between EGU NOX emissions and corresponding ozone concentrations at nonattainment and maintenance receptors of concern. For more information about how this assessment was performed, refer to the Ozone Transport Policy Analysis Technical Support Document.
	For each nonattainment or maintenance receptor identified for this proposal, the EPA evaluated the air quality improvement at that receptor that is expected from progressively more stringent upwind EGU NOX reductions in states that are linked to that receptor. For example, the EPA evaluated the Harford County Maryland receptor with all linked states controlling their emissions at $500 per ton. This assessment showed a 0.35 ppb reduction in expected ozone design values at $500 per ton. The residual design values at this site are still expected to exceed the 2008 ozone NAAQS with an average design value of 81.2 ppb and a maximum design value of 83.9 ppb. Next, the EPA evaluated this receptor with all linked states controlling their emissions at $1,300 per ton. This assessment showed a 0.94 ppb reduction in expected ozone design values. At a cost threshold of $1,300 per ton, the residual design values at this site are expected to continue to exceed the 2008 ozone NAAQS with an average design value of 80.6 ppb and a maximum design value of 83.3 ppb. With respect to this receptor, the EPA then evaluated each progressively more stringent uniform control stringency (i.e. $3,400 per ton; $5,000 per ton; $6,400 per ton; and $10,000 per ton). Generally, the EPA evaluated the air quality improvements at each monitoring site for each progressively more stringent uniform EGU NOX control level. This information is available in the Ozone Transport Policy Analysis TSD.
      This approach evaluates interstate ozone transport for each receptor independently. Also, by evaluating the downwind ozone impact of upwind reductions that are made in all linked states at the same uniform control stringency, this approach provides equitable treatment of all upwind states as to their contribution to each downwind receptor to which they are linked.
      The EPA aggregates the relevant data (i.e., cost of control, EGU NOX reduction potential, and downwind ozone reduction metrics) in a multi-factor test that allows the EPA to evaluate the cost-effectiveness of various levels of emission reductions and the resulting improvements in downwind ozone concentrations.
      This evaluation shows that meaningful EGU NOX reductions are available at reasonable cost and that these reductions can provide meaningful improvements in downwind ozone concentrations at the identified nonattainment and maintenance receptors for this proposal. For example, the combined downwind ozone improvement across nonattainment and maintenance receptors is approximately 19 ppb at the $1,300 per ton level. See Figure VI.A.
Figure VI.A. EGU Ozone season NOX Reduction Potential in 24 linked states and Corresponding Total Reduction in Downwind Ozone Concentrations at Nonattainment and Maintenance Receptors for each Uniform NOX Cost Evaluated

      Combining costs, EGU NOX reductions, and corresponding improvements in downwind ozone concentrations results in a "knee in the curve" at $1,300 per ton. This uniform cost of reduction represents the threshold at which EGU NOX reduction potential and corresponding downwind ozone air quality improvements are maximized with respect to marginal cost. That is, the ratio of emission reductions to marginal cost and the ratio of ozone improvements to marginal cost are maximized relative to the other uniform cost thresholds evaluated. Further, at higher cost thresholds, as a result of this analysis we do not anticipate significant additional reductions that would justify these higher costs.
      As part of this analysis, the EPA evaluates potential over-control with respect to whether (1) the expected ozone improvements would be sufficient or greater than necessary to resolve the downwind ozone pollution problem (i.e., resolving nonattainment or maintenance problems) or (2) the expected ozone improvements would reduce upwind state ozone contributions to below the screening threshold (i.e., 1% of the NAAQS).
      In EME Homer City, the Supreme Court held that EPA cannot "require[] an upwind State to reduce emissions by more than the amount necessary to achieve attainment in every downwind State to which it is linked." 134 S.Ct. at 1608. On remand from the Supreme Court, the D.C. Circuit held that this means that EPA might overstep its authority "when those downwind locations would achieve attainment even if less stringent emissions limits were imposed on the upwind States linked to those locations." EME Homer City II, slip op. at 14. The D.C. Circuit qualified this statement by noting that this "does not mean that every such upwind State would then be entitled to less stringent emission limits. Some of those upwind States may still be subject to the more stringent emissions limits so as not to cause other downwind locations to which those States are linked to fall into nonattainment." Id. at 14-15.
      Consistent with these instructions from the Supreme Court and the D.C. Circuit, the EPA evaluated whether reductions quantified under the evaluated cost thresholds can be anticipated to resolve any downwind nonattainment or maintenance problems (as defined in section V) and by how much.
      The EPA's assessment shows that the uniform control stringency represented by $500 per ton would resolve the maintenance problem at two downwind maintenance receptors -- Ocean County New Jersey (maximum design value of 75.9 ppb) and Oldham County Kentucky (maximum design value of 75.8 ppb). Because no state is linked solely to one of these maintenance receptors, resolving these downwind air quality impact does not fully address any individual upwind state's good neighbor obligation.
      This assessment shows that the uniform control stringency represented by $1,300 per ton would resolve maintenance problems at three additional downwind maintenance receptors  - - Baltimore County Maryland (maximum design value of 75.6 ppb), Hamilton County Ohio (maximum design value of 75.1 ppb), and Gloucester County New Jersey (maximum design value of 75.8 ppb). The EPA's assessment shows that this control level does resolve the only identified nonattainment or maintenance problem to which North Carolina is linked for this proposal  -  the Baltimore County Maryland maintenance receptor. The EPA therefore proposes that this EGU control level would fully address North Carolina's good neighbor obligation with respect to the 2008 ozone NAAQS. The EPA seeks comment on this determination.
      The EPA also proposes that, based on the information supporting this proposal, this level of EGU NOX control for North Carolina would not constitute over-control as to the Baltimore County receptor.  The level of the 2008 ozone standard NAAQS is 75 ppb.  At the uniform $1,300 per ton cost threshold, EPA's assessment demonstrates that the receptor would just be maintaining the standard, with a maximum design value of 75.6 ppb.  Therefore, the emissions reductions that would be achieved at the $1,300 per ton cost threshold would not result in air quality improvements at the Baltimore County receptor significantly better than the standard such the emission reductions might constitute over-control as to that receptor.  On the contrary, the emission reductions achieved in upwind states at the $1,300 per ton cost threshold are necessary to bring the maximum design value at the Baltimore County receptor into alignment with the standard. The EPA also seeks comment on this determination.
      For the remainder of the states for which the EPA is proposing FIPs in this action, none of these states are linked solely to one of these maintenance receptors with air quality resolved at the $1,300 per ton cost threshold. Therefore, resolving these downwind air quality impacts does not fully address any other individual upwind state's good neighbor obligation.
      As noted above the EPA is proposing that the $1,300 per ton EGU control level would fully address North Carolina's good neighbor obligation with respect to the 2008 ozone NAAQS. As such, based on the data supporting this proposal, North Carolina was excluded from assessment of air quality improvements at more stringent uniform EGU NOX control levels.
      The EPA's assessment shows that the uniform control stringency represented by $3,400 per ton would resolve the maintenance problem at two additional downwind maintenance receptors -- Denton County Texas (481211032)(maximum design value of 75.9 ppb) and Harris County Texas (482011050) (maximum design value of 75.9 ppb). Because no state is linked solely to one of these maintenance receptors, resolving these downwind air quality impacts does not fully address any individual upwind state's good neighbor obligation.
      The EPA provides this summary of the evaluation for the $500 per ton; $1,300 per ton; and $3,400 per ton uniform cost thresholds because, as described below, the EPA is proposing to use the $1,300 per ton level and is taking comment on using the $500 per ton level or $3,400 per ton level to quantify ozone season EGU NOX requirements to reduce interstate ozone transport for the 2008 ozone NAAQS. Further information on the EPA's evaluation of these cost thresholds as well as additional cost thresholds ($5,000 per ton; $6,400 per ton; and $10,000 per ton) are provided in the Ozone Transport Policy Analysis Technical Support Document. Additionally, Table VI.E-3 provides a summary of the expected number of nonattainment and maintenance-only receptors at the adjusted base case and cost thresholds.
Table VI.E-3 Number of Nonattainment or Maintenance Receptors after EGU NOX Mitigation
Cost Threshold
Nonattainment Receptors
Maintenance-Only Receptors
Base Case (IPM 5.15 w/CPP)
12
21
$500 per ton
12
19
$1,300 per ton
12
14
$3,400 per ton
12
13
$5,000 per ton
12
13
$6,400 per ton
12
13
$10,000 per ton
12
12

       In EME Homer City, the Supreme Court also held that "EPA cannot require a State to reduce its output of pollution . . . at odds with the one-percent threshold the Agency has set." 134 S.Ct. at 1608. The Court explained that "EPA cannot demand reductions that would drive an upwind State's contribution to every downwind State to which it is linked below one percent of the relevant NAAQS." Id. Accordingly, the EPA also evaluated the potential for over-control with respect to the 1% threshold proposed to be applied in this rule at each relevant cost threshold. Specifically, the EPA evaluated whether the uniform cost thresholds would reduce upwind EGU emissions to a level where the contribution from each upwind state would be below the 1% threshold that linked the upwind state to the downwind receptors. If the EPA found that any state's reduction obligation at the applied cost threshold decreased its contribution to every downwind receptor to which it is linked below the 1% threshold, we would need to adjust the state's reduction obligation accordingly. The EPA's assessment reveals that there is not over-control with respect to the 1% threshold at any of the evaluated uniform costs in any upwind state; in fact, even at the highest uniform cost threshold evaluated (e.g., $10,000 per ton), all upwind states that contributed greater than or equal to the 1% threshold in the base case continued to contribute greater than or equal to 1% of the NAAQS to at least one downwind nonattainment or maintenance receptor. Therefore, the EPA does not expect any of the uniform cost thresholds evaluated to result in over-control relative to the 1% threshold. For more information about this assessment, refer to the Ozone Transport Policy Analysis Technical Support Document.
      The EPA proposes to determine ozone season EGU NOX control requirements for upwind states to reduce interstate ozone transport for the 2008 ozone NAAQS based on the reduction potential quantified from pollution control measures that are cost-effective at the $1,300 per ton level. The EPA seeks comment on potentially basing these ozone season NOX control requirements on uniform cost levels that are less stringent ($500 per ton) or more stringent ($3,400 per ton), including comments on the proposed approach to addressing a state like North Carolina in such a situation, which is explained below..
      The EPA notes that the evaluation of cost, NOX reductions, and ozone improvements for the final rule could show different results for different states. For example, one or more states could fully address their good neighbor obligation based on ozone season NOX control requirements represented by one cost level while one or more other states would not fully address their good neighbor obligation at that level and would have ozone season NOX control requirements based on a more stringent cost level in order to fully address or make further progress toward partially addressing their good neighbor obligation. In this situation, the EPA proposes that it would quantify requirements for these different groups of states based on different uniform control stringencies. This could be similar to EPA's establishing two different SO2 groups under the original CSAPR as to addressing PM2.5 transport. The EPA seeks comment on this proposed approach for quantifying requirements.
      The EPA also seeks comment on implementation of the resulting emissions budgets. The EPA proposes that if there are groups of states with ozone season NO - X control requirements based on different cost levels, we would nevertheless finalize FIPs for the states in these groups of states that incorporate participation in a trading program that allows them to trade allowances with each other subject to limitations described in section VII of this proposal.
      By way of example and as noted above, the EPA is also seeking comment on potentially basing ozone season NOX control requirements on the $3,400 per ton uniform cost levels. If the EPA were to finalize ozone season NOX control requirements based on this level, given the specific data informing this proposal, then the EPA would set North Carolina's requirements based on the less stringent $1,300 per ton level because, as discussed above, the sole receptor to which North Carolina is linked for this proposal is resolved at the $1,300 per ton level with a maximum design value of 75.6 ppb. Therefore, because the $1,300 per ton level fully addresses North Carolina's good neighbor obligation, if EPA were to determine ozone season NOX control requirements based on the $3,400 per ton level for the remainder of states, the EPA would finalize good neighbor requirements for these two groups of states using different uniform control stringencies. The EPA proposes that it would finalize FIPs for the states that incorporate participation in a trading program that allows them to trade allowances with each other subject to limitations described in section VII of this proposal.
      The EPA's selection of reductions for this rule is specific to, and appropriate for, defining near-term achievable upwind obligations with respect to the 2008 ozone NAAQS in states where a FIP is necessary. We do not intend  -  nor do we believe we would be justified in doing so in any event  -  that the cost-level-based determinations in this proposed rule impose a constraint for selection of cost levels in addressing transported pollution with respect to future NAAQS and/or any revisions to these FIPs for any other future transport rules that the EPA may develop to address any potential remaining obligation as to the current NAAQS, for which different cost levels may be appropriate.
      As described above, the EPA is proposing that the NOX emission reductions associated with uniform control stringency represented by $1,300 per ton would not result in over-control at any of the identified non-attainment or maintenance receptors and it is reasonable to require such reductions from upwind states.
      The EPA requests comment on its proposal to quantify ozone season EGU NOX reductions to reduce interstate transport with respect to the 2008 ozone NAAQS using the $1,300 per ton uniform cost threshold.
      Note that our assessment of EGU NOX reduction potential shows zero reductions available in Delaware in 2017 at any evaluated cost threshold. At this time, because the assessment shows no EGU NOX reduction potential within Delaware up to $10,000 per ton and because Delaware does not currently participate in the original CSAPR NOX ozone-season allowance trading program, the EPA is not proposing to promulgate a FIP for Delaware to be included in this rule. However, as this assessment has only considered reductions available at EGUs by 2017, the EPA cannot at this time conclude that Delaware does not have reductions available on a longer timeframe or from other emission sectors. Accordingly, the EPA cannot conclude at this time that Delaware does not significantly contribute to nonattainment or interfere with maintenance at downwind receptors to which it is linked. The EPA will evaluate additional reduction potential from Delaware in a future rulemaking to address the 2008 ozone standard. The EPA seeks comment on not including Delaware in the proposed FIPs.
      The EPA's EGU NOX reduction assessment also shows zero reductions available in Wisconsin in 2017 at the proposed $1,300 per ton cost threshold. However, Wisconsin currently participates in the original CSAPR NOX ozone-season emissions trading program and Wisconsin's original CSAPR NOX ozone emissions budget is greater than its projected base case emissions. The EPA proposes to update Wisconsin's emissions budgets because not doing so would mean that Wisconsin, which is found to contribute above 1% to downwind ozone problems, could increase emissions above its base case level. The EPA proposes to determine ozone season NOX control requirements for Wisconsin to reduce interstate ozone transport for the 2008 ozone NAAQS based on the reduction potential quantified from pollution control measures that are cost-effective at the $1,300 per ton level. For Wisconsin, based on modeling for this proposal, this level is no different from its projected base-case level. The EPA seeks comment on the proposed FIP for Wisconsin.
 Quantifying State Emission Budgets
The proposed emission budgets reflect remaining EGU emissions after upwind states achieve the emission reduction obligations defined in section VI of this proposal.
In the original CSAPR proposal, the EPA set proposed emission budgets by using an approach that considered monitored state-level generation and modeled state-level emissions rates. However, for the CSAPR final rule, the EPA set budgets using only the modeling results from CSAPR's uniform cost assessment. For this rule, the EPA proposes to set emission budgets by considering monitored generation and modeled emissions rates, similar to the original CSAPR proposal. The EPA seeks comment on all aspects of quantifying state emission budgets reflecting upwind obligations.
The EPA proposes to quantify state emission budgets using the minimum of calculated EGU emissions budgets using the state-level EGU NOX emission rates that correspond to the upwind state reductions identified above using a uniform cost threshold of $1,300 per ton or 2014 monitored historic emissions.
The proposed approach for translating this EGU NOX reduction potential into emissions budgets is a four step process. First, the EPA would use the resulting 2018 state-level modeled EGU NOX emissions rate (lbs/mmBtu) from the IPM $1,300 per ton uniform cost assessment. The state-level rate is calculated as the total emissions from affected sources within the state, divided by the total heat input from these sources. Second, the EPA proposes to multiply this modeled state-level emissions rate by 2014 monitored historic state-level heat input. Multiplying the projected state-level emissions rate by historical heat input yields state-specific ozone season EGU NOX emissions for 2018. Third, the EPA proposes to add an adjustment to account for differences in unit availability between the IPM 2018 run year and 2017, yielding state-specific ozone season EGU NOX emissions for 2017. Finally, the EPA then proposes EGU emissions budgets as the minimum of this calculated 2017 emission level or 2014 historic monitored emissions.
This proposed approach reflects the EGU NOX reduction potential described above and grounds the EPA's quantification of emission budgets in historical data. The proposed EGU NOx ozone-season emission budgets calculated using this approach can be found in Table VI.1. Tables VI.2 and VI.3 provide the EGU NOX ozone-season emission budgets reflecting EGU NOX mitigation available for 2017 at $500 per ton and $3,400 per ton, respectively.
Table VI.1. Proposed EGU NOX Ozone-Season Emission Budgets, Reflecting EGU NOX mitigation Available for 2017 at $1,300 per ton
State
2014 Emissions (tons)
2018 $1,300/ton Emission Rate (lbs/MMBtu)
2014 Heat Input(MMBtu)
2017 Adjustment (tons)
2017 EGU NOx Ozone-Season Emission Budget (tons)
Alabama
                                                                         21,075
                                                                          0.049
                                                                    410,477,094
                                                                              0
                                                                          9,979
Arkansas
                                                                         18,135
                                                                          0.074
                                                                    185,511,093
                                                                             51
                                                                          6,949
Illinois
                                                                         17,520
                                                                          0.062
                                                                    388,382,456
                                                                              9
                                                                         12,078
Indiana
                                                                         40,247
                                                                          0.126
                                                                    447,417,615
                                                                              0
                                                                         28,284
Iowa
                                                                         13,857
                                                                           0.11
                                                                    151,989,571
                                                                              0
                                                                          8,351
Kansas
                                                                         12,297
                                                                           0.12
                                                                    154,921,650
                                                                              0
                                                                          9,272
Kentucky
                                                                         33,896
                                                                          0.102
                                                                    380,694,315
                                                                          2,169
                                                                         21,519
Louisiana
                                                                         18,278
                                                                          0.097
                                                                    326,662,000
                                                                             17
                                                                         15,807
Maryland
                                                                          4,026
                                                                           0.05
                                                                     86,239,563
                                                                          2,669
                                                                          4,026
Michigan
                                                                         25,065
                                                                          0.112
                                                                    307,723,171
                                                                          1,836
                                                                         19,115
Mississippi
                                                                         10,229
                                                                          0.069
                                                                    172,406,970
                                                                              0
                                                                          5,910
Missouri
                                                                         31,235
                                                                          0.086
                                                                    330,006,788
                                                                          1,210
                                                                         15,323
New Jersey
                                                                          2,746
                                                                          0.036
                                                                    112,887,439
                                                                              0
                                                                          2,015
New York
                                                                          5,547
                                                                          0.038
                                                                    235,619,397
                                                                              0
                                                                          4,450
North Carolina
                                                                         16,759
                                                                          0.078
                                                                    315,255,877
                                                                              0
                                                                         12,275
Ohio
                                                                         32,181
                                                                          0.073
                                                                    457,251,027
                                                                              0
                                                                         16,660
Oklahoma
                                                                         16,215
                                                                          0.144
                                                                    236,715,186
                                                                            154
                                                                         16,215
Pennsylvania
                                                                         44,551
                                                                          0.057
                                                                    508,608,673
                                                                              0
                                                                         14,387
Tennessee
                                                                          8,057
                                                                          0.056
                                                                    196,132,311
                                                                              0
                                                                          5,481
Texas
                                                                         58,492
                                                                          0.079
                                                                  1,474,773,212
                                                                             33
                                                                         58,002
Virginia
                                                                          9,695
                                                                          0.076
                                                                    179,324,728
                                                                              0
                                                                          6,818
West Virginia
                                                                         29,420
                                                                          0.084
                                                                    317,087,558
                                                                              0
                                                                         13,390
Wisconsin
                                                                          9,087
                                                                          0.054
                                                                    205,305,933
                                                                              0
                                                                          5,561
23 State Region
                                                                        478,610

                                                                  7,581,393,627
                                                                          8,147
                                                                        311,867

Table VI.2. Proposed EGU NOX Ozone-Season Emission Budgets, Reflecting EGU NOX mitigation Available for 2017 at $500 per ton
State
2014 Emissions (tons)
                                        2018 $500/ton Emission Rate (lbs/MMBtu)
2014 Heat Input(MMBtu)
2017 Adjustment (tons)
2017 EGU NOx Ozone-Season Emission Budget (tons)
Alabama
                                                                         21,075
                                                                          0.058
                                                                    410,477,094
                                                                              0
                                                                         11,886
Arkansas
                                                                         18,135
                                                                          0.075
                                                                    185,511,093
                                                                             51
                                                                          7,038
Illinois
                                                                         17,520
                                                                          0.062
                                                                    388,382,456
                                                                             23
                                                                         12,144
Indiana
                                                                         40,247
                                                                           0.15
                                                                    447,417,615
                                                                              0
                                                                         33,483
Iowa
                                                                         13,857
                                                                          0.113
                                                                    151,989,571
                                                                              0
                                                                          8,614
Kansas
                                                                         12,297
                                                                           0.12
                                                                    154,921,650
                                                                              0
                                                                          9,278
Kentucky
                                                                         33,896
                                                                          0.149
                                                                    380,694,315
                                                                          4,463
                                                                         32,783
Louisiana
                                                                         18,278
                                                                          0.097
                                                                    326,662,000
                                                                             17
                                                                         15,861
Maryland
                                                                          4,026
                                                                           0.05
                                                                     86,239,563
                                                                          2,672
                                                                          4,026
Michigan
                                                                         25,065
                                                                          0.131
                                                                    307,723,171
                                                                          1,836
                                                                         22,022
Mississippi
                                                                         10,229
                                                                          0.071
                                                                    172,406,970
                                                                              0
                                                                          6,083
Missouri
                                                                         31,235
                                                                          0.086
                                                                    330,006,788
                                                                          1,123
                                                                         15,380
New Jersey
                                                                          2,746
                                                                          0.036
                                                                    112,887,439
                                                                              0
                                                                          2,016
New York
                                                                          5,547
                                                                          0.039
                                                                    235,619,397
                                                                              0
                                                                          4,607
North Carolina
                                                                         16,759
                                                                          0.078
                                                                    315,255,877
                                                                              0
                                                                         12,278
Ohio
                                                                         32,181
                                                                          0.088
                                                                    457,251,027
                                                                              0
                                                                         20,194
Oklahoma
                                                                         16,215
                                                                          0.156
                                                                    236,715,186
                                                                            154
                                                                         16,215
Pennsylvania
                                                                         44,551
                                                                           0.15
                                                                    508,608,673
                                                                              0
                                                                         38,270
Tennessee
                                                                          8,057
                                                                          0.056
                                                                    196,132,311
                                                                              0
                                                                          5,520
Texas
                                                                         58,492
                                                                          0.083
                                                                  1,474,773,212
                                                                              0
                                                                         58,492
Virginia
                                                                          9,695
                                                                          0.078
                                                                    179,324,728
                                                                              0
                                                                          6,955
West Virginia
                                                                         29,420
                                                                          0.145
                                                                    317,087,558
                                                                              0
                                                                         22,932
Wisconsin
                                                                          9,087
                                                                          0.054
                                                                    205,305,933
                                                                              0
                                                                          5,588
23 State Region
                                                                        478,610

                                                                  7,581,393,627
                                                                         10,339
                                                                        371,665

Table VI.3. Proposed EGU NOX Ozone-Season Emission Budgets, Reflecting EGU NOX mitigation Available for 2017 at $3,400 per ton
State
2014 Emissions (tons)
2018 $3,400/ton Emission Rate (lbs/MMBtu)
2014 Heat Input(MMBtu)
2017 Adjustment (tons)
2017 EGU NOx Ozone-Season Emission Budget (tons)
Alabama
                                                                         21,075
                                                                          0.048
                                                                    410,477,094
                                                                              0
                                                                          9,931
Arkansas
                                                                         18,135
                                                                          0.065
                                                                    185,511,093
                                                                             51
                                                                          6,101
Illinois
                                                                         17,520
                                                                          0.062
                                                                    388,382,456
                                                                              0
                                                                         11,992
Indiana
                                                                         40,247
                                                                          0.123
                                                                    447,417,615
                                                                              0
                                                                         27,585
Iowa
                                                                         13,857
                                                                          0.107
                                                                    151,989,571
                                                                              0
                                                                          8,118
Kansas
                                                                         12,297
                                                                           0.12
                                                                    154,921,650
                                                                              0
                                                                          9,259
Kentucky
                                                                         33,896
                                                                          0.099
                                                                    380,694,315
                                                                          2,169
                                                                         20,945
Louisiana
                                                                         18,278
                                                                          0.094
                                                                    326,662,000
                                                                             17
                                                                         15,378
Maryland
                                                                          4,026
                                                                           0.05
                                                                     86,239,563
                                                                          2,523
                                                                          4,026
Michigan
                                                                         25,065
                                                                          0.108
                                                                    307,723,171
                                                                          1,978
                                                                         18,624
Mississippi
                                                                         10,229
                                                                          0.064
                                                                    172,406,970
                                                                              0
                                                                          5,487
Missouri
                                                                         31,235
                                                                          0.083
                                                                    330,006,788
                                                                          1,500
                                                                         15,240
New Jersey
                                                                          2,746
                                                                          0.036
                                                                    112,887,439
                                                                              0
                                                                          2,011
New York
                                                                          5,547
                                                                          0.037
                                                                    235,619,397
                                                                              0
                                                                          4,391
North Carolina
                                                                         16,759
                                                                          0.068
                                                                    315,255,877
                                                                              0
                                                                         10,705
Ohio
                                                                         32,181
                                                                          0.073
                                                                    457,251,027
                                                                              0
                                                                         16,637
Oklahoma
                                                                         16,215
                                                                          0.137
                                                                    236,715,186
                                                                            146
                                                                         16,215
Pennsylvania
                                                                         44,551
                                                                          0.056
                                                                    508,608,673
                                                                              0
                                                                         14,358
Tennessee
                                                                          8,057
                                                                          0.056
                                                                    196,132,311
                                                                              0
                                                                          5,449
Texas
                                                                         58,492
                                                                          0.076
                                                                  1,474,773,212
                                                                            100
                                                                         55,864
Virginia
                                                                          9,695
                                                                          0.065
                                                                    179,324,728
                                                                              0
                                                                          5,834
West Virginia
                                                                         29,420
                                                                          0.078
                                                                    317,087,558
                                                                              0
                                                                         12,367
Wisconsin
                                                                          9,087
                                                                          0.054
                                                                    205,305,933
                                                                              0
                                                                          5,511
23 State Region
                                                                        478,610

                                                                  7,581,393,627
                                                                          8,485
                                                                        302,028

 Implementation Using the Existing CSAPR NOX Ozone-Season Allowance Trading Program and Relationship to Other Rules
 Background
This section describes implementing and enforcing the budgets quantified in section VI. In the 4-step CSAPR methodology previously described, once emission reduction potential is quantified into emissions budgets, the remaining step is to identify an approach for ensuring that such reductions occur and are enforceable. As discussed previously, EPA is proposing implement the budgets to address the 2008 ozone NAAQS using the existing CSAPR trading program that allows limited interstate trading among states participating in the ozone-season trading program. The EPA proposes to revise the existing budgets, developed to address transport as to the 1997 ozone NAAQS, where necessary to reflect the additional reductions that the EPA identified as necessary to address transport as to the 2008 NAAQS. The EPA will implement the trading program in each affected state through the issuance of a FIP.
In electing to propose to implement these near-term EGU reductions for the 2008 ozone standard using the existing CSAPR trading infrastructure, the EPA considered the many significant advantages of continuing to use the existing CSAPR program, including the ease of transition to the new budgets, the economic and administrative efficiency of trading approaches, and the flexibility afforded to sources regarding compliance.
      The EPA also considered views expressed by some stakeholders that a complementary short-term (e.g., 30-day) rate-based limit would ensure that control measures adopted to meet the revised budgets continue to operate over time. Some stakeholders have observed, for example, that some existing SCR and SNCR units may not have operated in recent years because CAIR allowance prices are below the operating costs of the controls. The EPA notes that in such cases, the CAIR emission budgets that states were required to meet to address significant contribution for the 1997 NAAQS were in fact still being met. The EPA will also evaluate power sector behavior for 2015, the first year of CSAPR implementation, and provide that assessment for the final rule. The EPA expects that certain aspects of this proposal will alleviate some of these concerns. In particular, this proposal is aimed at establishing new, lower emissions budgets that are calculated based on a uniform cost that is reflective of, among other things, operating those controls. Furthermore, as described later in this notice, we are proposing adjustments to the CSAPR regulations that, if adopted, would address the role that the banked allowances may play in allowance prices. For these reasons, the EPA does not believe that including a short-term complementary rate-based limit in the proposed FIPs is necessary. Nevertheless, we invite comment on the need for such an approach and, from commenters arguing that it is needed, we invite suggestions for calculating it.
As explained in greater detail in section IV, under CAA sections 110(a)(1) and 110(a)(2), each state is required to submit a SIP that provides for the implementation, maintenance, and enforcement of each primary or secondary NAAQS. According to section 110(a)(2)(D)(i)(I), the SIP for each state, regardless of a state's designation status for the relevant NAAQS, must prohibit sources or other types of emissions activity from emitting any air pollutant in amounts that will "contribute significantly to nonattainment" of the standard in a downwind state or "interfere with maintenance" of the standard in a downwind state. Section IV also explains in detail that the EPA is obligated to promulgate FIPs when we find that a state fails to submit a complete SIP or the EPA disapproves a SIP submittal.
The EPA recognizes that several states included in this proposal have submitted transport SIPs to address the 2008 ozone standard that the EPA is reviewing, and it is possible that additional states may submit SIPs in the future. As explained in section IV above, the EPA may only finalize FIPs for states where FIP authority exists; that is, for states where either the EPA found that the state failed to submit a complete transport SIP or where the EPA has disapproved a transport SIP submittal for that state. The EPA intends to finalize these proposed FIPs together in a single action and, to the greatest extent possible, the EPA intends to take final action on SIP submittals currently before the agency prior to finalizing this proposal. In the event that a state plans to revise its SIP or submit a SIP prior to any final rule, contact your regional office to alert the EPA.
By this action, the EPA is proposing federal implementation plans with respect to the 2008 ozone NAAQS for each state potentially covered by this rule. Section VI above describes the EPA's approach to defining state-level EGU emission budgets that represent the EGU emissions remaining after reducing that state's significant contribution to downwind nonattainment and/or interference with maintenance. The EPA is proposing to implement these EGU emission budgets in the FIPs through the CSAPR EGU NOX ozone-season trading program.
When the EPA finalized CSAPR in 2011 under the good neighbor provision of the CAA to reduce emissions of SO2 and NOX from power plants in eastern states, the rule put in place regional trading programs to quickly and cost-effectively address pollution that affects air quality in downwind states. The EPA envisioned that the methodology could be used to address transport concerns under other existing NAAQS and future NAAQS revisions. See 76 FR 48211 and 48246, August 8, 2011. Accordingly, the EPA proposes to use the CSAPR ozone-season trading program and related provisions as codified under 40 CFR Part 97, Subpart BBBBB and section 52.38, as amended in this proposal, to implement the proposed EGU NOX ozone-season emission budgets for the 2008 ozone NAAQS. This program will be initially implemented in each state through a FIP.
In this notice, the EPA proposes that the first control period for the requirements is the 2017 ozone season. A covered state would be required to demonstrate compliance with FIP requirements for each subsequent ozone season until it submits, and the EPA approves, a SIP or the EPA promulgates another federal rule replacing the FIP.
The EPA notes that the compliance flexibility provided by the CSAPR NOX ozone-season trading program allows sources to demonstrate compliance by holding allowances and does not prescribe unit-specific and technology-specific NOX mitigation. In other words, while the EPA quantified EGU NOX reductions resulting from mitigation strategies such as operating or installing (or upgrading to) state-of-the-art combustion controls, no particular reduction strategy is required for any specific unit because the Act only requires that an upwind state's aggregate emissions neither significantly contribute to nonattainment nor interfere with maintenance of the NAAQS in a downwind state.
In practice, the EGU emission budgets that the EPA is proposing in this action are achievable for each of the 23 states through operating existing SCR and SNCR controls, installing or upgrading to state-of-the-art combustion controls, or shifting generation to low-NOX emitting units. The EPA believes that this proposed rule provides sufficient lead time to implement these control strategies by the 2017 ozone season. For the EPA's assessment of the feasibility of controls for 2017, refer to section VI above and the EGU NOX Reduction TSD in the docket for this proposal.