7,515
Arizona
                                                                          5,389
                                                                          5,100
                                                                          4,616
                                                                          4,616
                                                                          4,816
                                                                          3,916
Arkansas
                                                                          8,731
                                                                          8,655
                                                                          8,708
                                                                          8,708
                                                                          6,642
                                                                          4,661
California
                                                                          1,104
                                                                          1,103
                                                                          1,055
                                                                          1,053
                                                                          1,053
                                                                          1,053
Colorado
                                                                          5,950
                                                                          5,953
                                                                          5,938
                                                                          5,916
                                                                          5,085
                                                                          3,826
Connecticut
                                                                            341
                                                                            313
                                                                            304
                                                                            304
                                                                            302
                                                                            302
Delaware
                                                                            220
                                                                            220
                                                                            203
                                                                            202
                                                                            194
                                                                            194
Florida
                                                                         13,938
                                                                         13,929
                                                                         12,604
                                                                         12,523
                                                                         11,882
                                                                         11,188
Fort Mojave
                                                                             53
                                                                             53
                                                                             53
                                                                             53
                                                                             53
                                                                             53
Georgia
                                                                          7,154
                                                                          7,154
                                                                          7,129
                                                                          7,129
                                                                          7,097
                                                                          7,097
Idaho
                                                                            204
                                                                            204
                                                                            204
                                                                            204
                                                                            204
                                                                            204
Illinois
                                                                          8,281
                                                                          8,261
                                                                          8,143
                                                                          8,047
                                                                          7,228
                                                                          6,880
Indiana
                                                                         12,232
                                                                         12,083
                                                                          9,585
                                                                          9,564
                                                                          8,923
                                                                          8,430
Iowa
                                                                          7,647
                                                                          7,531
                                                                          6,753
                                                                          6,753
                                                                          5,201
                                                                          2,817
Kansas
                                                                          6,057
                                                                          6,053
                                                                          5,384
                                                                          5,338
                                                                          4,815
                                                                          3,658
Kentucky
                                                                         14,551
                                                                         14,567
                                                                         13,352
                                                                         13,345
                                                                         11,796
                                                                          9,529
Louisiana
                                                                         15,476
                                                                         15,430
                                                                         15,389
                                                                         14,818
                                                                         14,378
                                                                         12,622
Maine
                                                                             67
                                                                             67
                                                                             67
                                                                             67
                                                                             67
                                                                             67
Maryland
                                                                          1,350
                                                                          1,350
                                                                          1,348
                                                                          1,348
                                                                          1,168
                                                                          1,168
Massachusetts
                                                                            320
                                                                            317
                                                                            317
                                                                            315
                                                                            307
                                                                            307
Michigan
                                                                         11,009
                                                                         10,211
                                                                          9,804
                                                                          9,800
                                                                          8,678
                                                                          7,352
Minnesota
                                                                          4,655
                                                                          4,545
                                                                          4,198
                                                                          4,198
                                                                          3,034
                                                                          2,581
Mississippi
                                                                          8,070
                                                                          8,067
                                                                          7,739
                                                                          7,739
                                                                          7,081
                                                                          6,436
Missouri
                                                                         12,147
                                                                         12,088
                                                                         11,061
                                                                         10,985
                                                                         10,732
                                                                          9,288
Montana
                                                                          3,249
                                                                          3,249
                                                                          3,249
                                                                          3,249
                                                                          2,445
                                                                          1,544
Navajo
                                                                          1,319
                                                                          1,319
                                                                          1,319
                                                                          1,319
                                                                          1,319
                                                                          1,319
Nebraska
                                                                          7,347
                                                                          7,283
                                                                          7,299
                                                                          7,299
                                                                          5,966
                                                                          4,246
Nevada
                                                                          1,386
                                                                            828
                                                                            479
                                                                            479
                                                                            332
                                                                            100
New Hampshire
                                                                            386
                                                                            386
                                                                            299
                                                                            299
                                                                            299
                                                                            299
New Jersey
                                                                          1,346
                                                                          1,346
                                                                          1,253
                                                                          1,253
                                                                          1,257
                                                                          1,257
New Mexico
                                                                          1,693
                                                                          1,673
                                                                          1,594
                                                                          1,594
                                                                          1,187
                                                                          1,187
New York
                                                                          3,456
                                                                          3,450
                                                                          3,403
                                                                          3,403
                                                                          3,297
                                                                          3,297
North Carolina
                                                                         14,281
                                                                         14,188
                                                                          9,632
                                                                          9,538
                                                                          7,055
                                                                          4,483
North Dakota
                                                                          9,166
                                                                          9,128
                                                                          9,091
                                                                          8,452
                                                                          7,237
                                                                          2,250
Ohio
                                                                         15,927
                                                                         15,569
                                                                          9,773
                                                                          9,773
                                                                          9,644
                                                                          9,222
Oklahoma
                                                                          8,964
                                                                          8,878
                                                                          8,717
                                                                          8,717
                                                                          7,820
                                                                          7,251
Oregon
                                                                            350
                                                                            350
                                                                            350
                                                                            350
                                                                            350
                                                                            350
Pennsylvania
                                                                         11,896
                                                                         11,806
                                                                          8,373
                                                                          8,373
                                                                          7,921
                                                                          7,851
Rhode Island
                                                                            233
                                                                            233
                                                                            233
                                                                            233
                                                                            233
                                                                            233
South Carolina
                                                                          4,903
                                                                          4,903
                                                                          3,769
                                                                          3,769
                                                                          3,762
                                                                          3,762
South Dakota
                                                                            591
                                                                            583
                                                                            581
                                                                            581
                                                                            583
                                                                            583
Tennessee
                                                                          3,953
                                                                          3,954
                                                                          3,907
                                                                          3,907
                                                                          3,826
                                                                          3,826
Texas
                                                                         43,125
                                                                         42,199
                                                                         40,708
                                                                         40,667
                                                                         35,207
                                                                         29,325
Utah
                                                                          6,729
                                                                          4,862
                                                                          4,837
                                                                          4,837
                                                                          5,094
                                                                          3,174
Ute
                                                                          2,144
                                                                          2,144
                                                                          2,144
                                                                          2,144
                                                                          1,608
                                                                            573
Vermont
                                                                             51
                                                                             51
                                                                             51
                                                                             51
                                                                             51
                                                                             51
Virginia
                                                                          4,162
                                                                          4,158
                                                                          3,839
                                                                          3,795
                                                                          3,745
                                                                          3,312
Washington
                                                                          1,609
                                                                          1,609
                                                                          1,609
                                                                          1,603
                                                                          1,603
                                                                            761
West Virginia
                                                                         15,165
                                                                         15,017
                                                                         13,205
                                                                         12,884
                                                                         12,837
                                                                         10,568
Wisconsin
                                                                          3,769
                                                                          3,660
                                                                          3,519
                                                                          3,512
                                                                          3,490
                                                                          3,490
Wyoming
                                                                         10,337
                                                                         10,337
                                                                          9,480
                                                                          9,480
                                                                          6,997
                                                                          3,972
12 Linked States Total
                                                                        114,850
                                                                        113,248
                                                                         97,467
                                                                         96,403
                                                                         90,872
                                                                         81,488

As noted in Section VI of the Preamble, EPA identified $1,800 per ton as the point for determining significant contribution from EGUs under the Step 3 multifactor test.  Section VII explains that EPA applied this cost threshold to each year through 2024 to arrive at a budget estimate for that year.  Those state-level emissions budgets for the 12 states along with the corresponding percent reduction relative to 2019 and the state's baseline emissions for that year are shown below in Tables C-6 through C-10.

Table C-6 - OS NOx, 2021 Emissions Budget, and % Reduction

2016 OS NOx
2019 OS NOx
Baseline 2021 OS NOx
2021 Budget
% Reduction from 2019
% Reduction from 2021 Baseline
Illinois
                                    14,553
                                    11,877
                                     9,368
                                     9,102
                                      23%
                                      3%
Indiana
                                    34,636
                                    16,594
                                    15,856
                                    13,051
                                      21%
                                      18%
Kentucky
                                    25,403
                                    19,117
                                    15,588
                                    15,300
                                      20%
                                      2%
Louisiana
                                    19,615
                                    15,365
                                    15,476
                                    14,818
                                      4%
                                      4%
Maryland
                                     4,471
                                     1,662
                                     1,501
                                     1,499
                                      10%
                                      0%
Michigan
                                    17,632
                                    14,055
                                    13,898
                                    12,727
                                      9%
                                      8%
New Jersey
                                     2,463
                                     1,346
                                     1,346
                                     1,253
                                      7%
                                      7%
New York
                                     6,534
                                     3,225
                                     3,469
                                     3,416
                                      -6%
                                      2%
Ohio
                                    24,205
                                    16,390
                                    15,829
                                     9,690
                                      41%
                                      39%
Pennsylvania
                                    31,896
                                    12,093
                                    11,896
                                     8,379
                                      31%
                                      30%
Virginia
                                     9,833
                                     4,668
                                     4,664
                                     4,516
                                      3%
                                      3%
West Virginia
                                    21,178
                                    15,615
                                    15,165
                                    13,334
                                      15%
                                      12%
Total
                                    212,418
                                    132,006
                                    124,057
                                    107,085
                                      19%
                                     13.7%

Table C-7. OS NOx, 2022 Emissions Budget, and % Reduction

2016 OS NOx
2019 OS NOx
Baseline 2022 OS NOx
2022 Budget
% Reduction from 2019
% Reduction from 2022 Baseline
Illinois
                                    14,553
                                    11,877
                                     9,368
                                     9,102
                                      23%
                                      3%
Indiana
                                    34,636
                                    16,594
                                    15,383
                                    12,582
                                      24%
                                      18%
Kentucky
                                    25,403
                                    19,117
                                    15,588
                                    14,051
                                      27%
                                      10%
Louisiana
                                    19,615
                                    15,365
                                    15,476
                                    14,818
                                      4%
                                      4%
Maryland
                                     4,471
                                     1,662
                                     1,267
                                     1,266
                                      24%
                                      0%
Michigan
                                    17,632
                                    14,055
                                    13,459
                                    12,290
                                      13%
                                      9%
New Jersey
                                     2,463
                                     1,346
                                     1,346
                                     1,253
                                      7%
                                      7%
New York
                                     6,534
                                     3,225
                                     3,469
                                     3,416
                                      -6%
                                      2%
Ohio
                                    24,205
                                    16,390
                                    15,927
                                     9,773
                                      40%
                                      39%
Pennsylvania
                                    31,896
                                    12,093
                                    11,896
                                     8,373
                                      31%
                                      30%
Virginia
                                     9,833
                                     4,668
                                     4,274
                                     3,897
                                      17%
                                      9%
West Virginia
                                    21,178
                                    15,615
                                    15,165
                                    12,884
                                      17%
                                      15%
Total
                                    212,418
                                    132,006
                                    122,619
                                    103,705
                                      21%
                                     15.4%

Table C-8. OS NOx, 2023 Emissions Budget, and % Reduction

2016 OS NOx
2019 OS NOx
Baseline 2023 OS NOx
2023 Budget
% Reduction from 2019
% Reduction from 2023 Baseline
Illinois
                                    14,553
                                    11,877
                                     8,413
                                     8,179
                                      31%
                                      3%
Indiana
                                    34,636
                                    16,594
                                    15,357
                                    12,553
                                      24%
                                      18%
Kentucky
                                    25,403
                                    19,117
                                    15,588
                                    14,051
                                      27%
                                      10%
Louisiana
                                    19,615
                                    15,365
                                    15,476
                                    14,818
                                      4%
                                      4%
Maryland
                                     4,471
                                     1,662
                                     1,267
                                     1,266
                                      24%
                                      0%
Michigan
                                    17,632
                                    14,055
                                    11,182
                                     9,975
                                      29%
                                      11%
New Jersey
                                     2,463
                                     1,346
                                     1,346
                                     1,253
                                      7%
                                      7%
New York
                                     6,534
                                     3,225
                                     3,474
                                     3,421
                                      -6%
                                      2%
Ohio
                                    24,205
                                    16,390
                                    15,927
                                     9,773
                                      40%
                                      39%
Pennsylvania
                                    31,896
                                    12,093
                                    11,896
                                     8,373
                                      31%
                                      30%
Virginia
                                     9,833
                                     4,668
                                     4,361
                                     3,980
                                      15%
                                      9%
West Virginia
                                    21,178
                                    15,615
                                    15,165
                                    12,884
                                      17%
                                      15%
Total
                                    212,418
                                    132,006
                                    119,453
                                    100,526
                                      24%
                                     15.8%

Table C-9. OS NOx, 2024 Onward: Emissions Budget, and % Reduction

2016 OS NOx
2019 OS NOx
Baseline 2024 OS NOx
2024 Budget
% Reduction from 2019
% Reduction from 2024 Baseline
Illinois
                                    14,553
                                    11,877
                                     8,292
                                     8,059
                                      32%
                                      3%
Indiana
                                    34,636
                                    16,594
                                    12,232
                                     9,564
                                      42%
                                      22%
Kentucky
                                    25,403
                                    19,117
                                    15,588
                                    14,051
                                      27%
                                      10%
Louisiana
                                    19,615
                                    15,365
                                    15,476
                                    14,818
                                      4%
                                      4%
Maryland
                                     4,471
                                     1,662
                                     1,350
                                     1,348
                                      19%
                                      0%
Michigan
                                    17,632
                                    14,055
                                    10,968
                                     9,786
                                      30%
                                      11%
New Jersey
                                     2,463
                                     1,346
                                     1,346
                                     1,253
                                      7%
                                      7%
New York
                                     6,534
                                     3,225
                                     3,456
                                     3,403
                                      -6%
                                      2%
Ohio
                                    24,205
                                    16,390
                                    15,927
                                     9,773
                                      40%
                                      39%
Pennsylvania
                                    31,896
                                    12,093
                                    11,896
                                     8,373
                                      31%
                                      30%
Virginia
                                     9,833
                                     4,668
                                     4,025
                                     3,663
                                      22%
                                      9%
West Virginia
                                    21,178
                                    15,615
                                    15,165
                                    12,884
                                      17%
                                      15%
Total
                                    212,418
                                    132,006
                                    115,722
                                    96,975
                                      27%
                                     16.2%

Table C-10. Emission Reduction Attributable to Generation Shifting (for 12 linked states).

Baseline OS NOx
Budget Without Gen Shifting
Budget With Gen. Shifting
% Reduction from Generation Shifting as a Percentage of Baseline
                                                                           2021
                                                                        124,057
                                                                        109,578
                                                                        107,085
                                                                             2%
                                                                           2022
                                                                        122,619
                                                                        106,211
                                                                        103,705
                                                                             2%
                                                                           2023
                                                                        119,453
                                                                        103,077
                                                                        100,526
                                                                             2%
                                                                           2024
                                                                        115,722
                                                                         99,446
                                                                         96,975
                                                                             2%

    Variability Limits and RIA Scenarios
      Once EPA determined state-emission budgets, EPA calculated the variability limits and assurance levels for each state based on the calculated emission budgets. Each state's variability limit is 21% of its budget, and its assurance level is the sum of its budget and variability limit (or 121% of its budget). The variability limits and assurance levels are further described and shown in section VII of the preamble for the Revised CSAPR Update and shown in Table Appendix G-1.
      As explained in the preamble, the EPA is finalizing EGU NOX ozone season emission budgets reflecting the uniform cost threshold of $1,800 per ton to eliminate significant contribution to nonattainment and interference with maintenance.
      For the RIA analysis, EPA used the budgets informed by the $1,800 per ton cost threshold scenario. Additionally, the RIA includes analysis of the less stringent policy option, using the budgets from a $500 per ton cost threshold case, and a more stringent policy alternative, using 2025 budgets from the $9,600 per ton cost threshold case reflecting SCR retrofits at coal units greater than 100 MW lacking such controls.
      The IPM runs performed for this analysis are listed in Appendix C of this TSD.  Table Appendix C-1 lists the name of each IPM run next to a description of the run.  The output files of these model runs can be found in the rulemaking docket.  Detailed budget calculations for all cost per ton cases can be found in Appendix A  -  Final Rule State Emission Budget Calculations and Engineering Analytics.

D. Analysis of Air Quality Responses to Emission Changes Using an Ozone Air Quality Assessment Tool (AQAT)

      EPA has defined each linked upwind state's significant contribution to nonattainment and interference with maintenance of downwind air quality using a multi-factor test (described in the preamble at section VI in step three of the 4-Step Good Neighbor Framework) which is based on cost, emissions, and air quality factors. A key quantitative input for determining the amount of each state's emission reduction obligation is the predicted downwind ambient air quality impacts of upwind EGU emission reductions under the budgets at various levels of NOX emission control and under a scenario of potential upwind non-EGU emissions reductions.  See section C of this TSD for information regarding EGUs and see preamble section VI for information about non-EGUs.  The emission reductions from the various cost thresholds can potentially result in air quality improvements such that individual receptors drop below the level of the NAAQS based on the cumulative air quality improvement from the upwind states, or potentially decrease each upwind state's contributions such that they possibly drop below the 1% linkage threshold (used in step two of the Good Neighbor Framework to identify the states for further analysis).
      Air quality modeling would be the optimal way to examine these questions at each cost threshold level from EGUs and non-EGUs.  However, due to time and resource limitations EPA was unable to use photochemical air quality modeling for all but a few emissions scenarios.  Therefore, in order to estimate the air quality impacts for the various levels of emission reductions and to ensure that each step of its analysis is informed by the evolving emissions data, EPA used a simplified air quality assessment tool (AQAT).  The simplified tool allows the Agency to analyze many more NOX emission budget levels than would otherwise be possible. EPA recognizes that AQAT is not the equivalent of photochemical air quality modeling.  However, AQAT is directly informed by air quality modeling data.  Further, AQAT has evolved through iterative development under the original CSAPR and the CSAPR Update.  One such evolution is its calibration of the change in air quality based on air quality modeling of a particular emission reduction scenario.  As done at proposal, EPA examined various cost threshold scenarios for the year 2024 using two different calibration factors as a mechanism to estimate the range of results.
       The inputs and outputs of the tool can be found in the "Ozone_AQAT_Final.xlsx" excel workbook.

      The remainder of section D of this document will:

          Present an introduction and overview of the ozone AQAT;
          Describe the construction of the ozone AQAT; and
          Provide the results of the NOX emission cost threshold analyses.

1. Introduction: Development of the ozone AQAT

      The ozone AQAT was developed for use in the rule's step three air quality analysis as part of the multi-factor test.  Specifically, the AQAT was designed to evaluate air quality changes in response to emissions changes in order to quantify necessary emission reductions under the good neighbor provision and to evaluate potential budgets for over-control as to either the 1% threshold or the downwind receptor status. EPA described and used a similar tool in the original CSAPR to evaluate good neighbor obligations with respect to the fine particulate matter (PM2.5) NAAQS and in the CSAPR Update to evaluate good neighbor obligations with respect to ozone.  For the CSAPR Update, EPA refined both the construction and application of the assessment tool for use in estimating changes in ozone concentrations in response to changes in NOX emissions.  We followed the methodology developed in the CSAPR Update rulemaking where we calibrate the response of a pollutant using two CAMx simulations at different emission levels.[,]  The construction of the AQAT for the final rule is essentially the same as that for the proposed rule.
      A critical factor in the assessment tool is the establishment of a relationship between ozone season NOX emission reductions and reductions in ozone. Within AQAT, on a receptor-by-receptor basis, we assume that the reduction of a ton of emissions of NOX from the upwind state results in a particular level of improvement in air quality downwind.  For the purposes of developing and using an assessment tool to compare the air quality impacts of NOX emission reductions under various emission cost threshold emission levels, we determine the relationship between changes in emissions and changes in ozone contributions on a receptor-by-receptor basis.  Specifically, EPA assumed that, within the range of total NOX emissions being considered (as defined by the cost threshold emission levels or changes from year-to-year), a change in ozone season NOX emissions leads to a proportional change in downwind ozone contributions.  This proportional relationship was then modified using calibration factors created using the 2023 base case contribution air quality modeling and either the 2016 base case (for cases between 2016 and 2023) or the 2028 base case (for cases from 2023 to 2028) to account for the majority of the nonlinearity between emissions and ozone concentrations.  For example, for a particular receptor in 2022, we could assume that a 20% decrease in the upwind state's emissions leads to a 20% decrease in its downwind ozone contribution in the "uncalibrated" ozone AQAT, while following the application of the calibration factor (based on the change to 2016) it may only decrease by 10% in "calibrated" AQAT (where the calibration factor is 0.5).  Typically, the calibration factors were substantially less than one, often on the order of 0.3 (thus, a 10% decrease in emissions would result in a 3% decrease in ozone concentration).  The creation of the calibration factors is described in detail in section D.2.c (1) of this TSD.
      In summary, because the tool is only being used over a range for which a calibration factor has been developed, and because other options such as using CAMx to model all scenarios is cost and time-prohibitive, EPA used ozone AQAT to estimate the downwind ozone reductions due to upwind NOX emission reductions for the air quality input to the multi-factor test for this rule.  Other options, such as directly scaling the results (i.e., an "uncalibrated ozone AQAT") will likely greatly overestimate the air quality impacts of emission reductions.
      Section D.2, below, is a technical explanation of the construction of the ozone AQAT.  Readers who prefer to access the results of the analysis using the ozone AQAT are directed to section D.3.

2.  Details on the construction of the ozone AQAT

 (a) Overview of the ozone AQAT

      This section describes the step-by-step development process for the ozone AQAT.  All the input and output data can be found in the Excel worksheets described in Appendix B.  In the ozone AQAT, EPA links state-by-state NOX emission reductions (derived from the photochemical model, the non-EGU assessment and/or the IPM EGU modeling combined with the EGU engineering assessment) with 2023 CAMx modeled ozone contributions in order to predict ozone concentrations at different levels of emission levels at monitoring sites.  The reduction in ozone contributions for each year at each cost threshold level and the resulting air quality improvement at monitoring sites with projected nonattainment and/or maintenance problems were then considered in a multi-factor test for identifying the level of emissions reductions that define significant contribution to nonattainment and interference with maintenance.
      In applying AQAT to analyze air quality improvements at a given receptor for the cost threshold scenarios, emissions were reduced in only those upwind states that were "linked" to that receptor in step 2 of the Good Neighbor Framework (i.e., those states that contributed an air quality impact at or above 1 percent of the NAAQS).  Emissions were also reduced in the state that contained that receptor (regardless of the level of that state's contribution) at a level of control stringency consistent with the budget level applied in upwind states.

      Specifically, the key estimates from the ozone AQAT for each receptor are:

          The ozone contribution as a function of emissions at each cost threshold level, for each upwind state that is contributing above the 1 percent air quality threshold and the state containing the receptor.
          The ozone contribution under base case NOX emissions in the various years, for each upwind state that is not above the 1 percent air quality threshold for that receptor.
          The non-anthropogenic (i.e., background, boundary, biogenic, and wildfire) ozone concentrations.  These are assumed to be constant and equal to the contributions from the 2023 base case source apportionment modeling.

The results of the ozone AQAT analysis for each emission cost threshold level for EGUs and non-EGUs can be found in section D.3 of this document.

(b) Data used to construct the ozone AQAT for this rule

      Several air quality modeling and emissions inventory sources were used to construct the calibrated ozone AQAT for this rule.  Using the calibration factors, EPA modulated the 2023 CAMx ozone season contributions for each upwind state to each downwind receptor.  These modulations were enough to adjust the concentrations to represent a different year (e.g., 2021).  In all cases, the starting point was the 2023 base case CAMx run with contributions. For each scenario, EPA multiplied each state's percent change in emissions relative to the 2023 base case ozone season NOX emission inventories from all source sectors used in the source apportionment CAMx air quality modeling (this includes all anthropogenic sources and excludes biogenic sources and wildfires) by the receptor-specific calibration factor and the state's base case contribution.  Note that the 2023 scenario in CAMx used IPM emission estimates while the 2016 base case used EGU continuous emissions monitoring system (CEMS) data.  The base case emission inventories for the 2023 base case and the 2016 and 2028 base cases are discussed in the Air Quality Modeling TSD.  An additional emission inventory (i.e., for 2021) was also developed.  The EGU emissions for this inventory were replaced with emission estimates used throughout Step 3.  This emission inventory is described in the Emission Inventory TSD. The ozone season NOX EGU and non-EGU emissions for each emission scenario including the base case as modeled in AQAT are described in section C of this TSD.
      As described in the Air Quality Modeling TSD, the air quality contributions and emissions were modeled for all states in the contiguous United States and the District of Columbia.  Thus, in the ozone AQAT, any emission differences between the 2023 air quality modeling base case and the scenario would result in changes in air quality contributions and ozone concentrations at the downwind monitors.

(c) Detailed outline of the process for constructing and utilizing the ozone AQAT

      The ozone AQAT was created and used in a multi-step process.  First, a calibrated ozone AQAT was created using the contributions and emission inventory from the 2023 base case air quality modeling as well as the 2016 base case (for all scenarios with years greater than or equal to 2023, the calibrated AQAT used the design values and emission inventory from the 2028 base case).  The construction of this was identical to that from the proposal.  For each emissions cost threshold scenario evaluated, for each state, EPA identified the percent change in anthropogenic NOX emissions relative to the 2023 base case and multiplied this by the receptor-specific calibration factor as well as by the state- and receptor-specific contribution.  This resulted in a state- and receptor-specific "change in contribution" relative to the 2023 base case.  Each state's change in contribution value was then added to (or subtracted from) its 2023 base case contribution and the results summed for all states for each receptor.  To this total of each state's contribution to each receptor, the receptor-specific base case contributions from the other source-categories were added (modified if necessary in the same way if necessary to adjust to a different year), resulting in an estimated design value for each receptor. The calibrated ozone AQAT was used to project the ozone concentrations for each NOX emission budget level on a receptor-by-receptor basis for every monitor throughout the domain.
      In order to facilitate understanding of the calibration process, EPA describes below a demonstrative example: monitor number 090019003 in Fairfield County, Connecticut, with a 2023 base case projected ozone average design value of 76.9 parts per billion (ppb) and maximum design value of 77.2 ppb.

(1)  Create the calibration factors

      The process for creating the calibration factors remains unchanged from the method used in the CSAPR Update.  This section repeats the process and data from the proposal.  To create the calibration factors, EPA used emissions, contributions, and design values from the 2023 CAMx run that used IPM for emissions, and the emissions and design values from either the 2016 or 2028 CAMx base cases. All changes in emissions and air quality are relative to the proposed 2023 CAMx base case.
      First, EPA used ozone season state-level 2023 base case total NOX emissions from all source sectors.  This emissions data is divided into multiple source sectors for the purposes of air quality modeling: airports, beis, cmv_c1c2_12, cmv_c3_12, nonpt, nonroad, np_oilgas, onroad, pt_oilgas, ptagfire, ptegu, ptfire, ptnonipm, rail, rwc (see the Preparation of Emissions Inventories for 2016v1 North American Emissions Modeling Platform TSD for additional details on the emissions inventories used in the CAMx air quality modeling).  The anthropogenic state-level total NOX emissions used in the air quality contribution modeling are the sum of emissions from all these source sectors except (beis, ptagfire, and ptfire).  Next, EPA summed the ozone season total anthropogenic NOX emissions across all relevant source sectors for both the 2016 and 2028 base cases.  EPA calculated the ratio of the emissions for each of these two base cases to the total emissions for the 2023 base case for each state modeled in CAMx.  More information on the emissions inventories can be found in the preamble to the proposed rule. The total emissions data and resulting ratios can be found in Table D-1 and in the ozone AQAT worksheet "calib_emiss".
      For each monitor, the "uncalibrated" change in concentration was found by multiplying each state's 2023 base case ozone air quality contribution by the difference in the state's ratio of emissions.  The difference in the ratio of emissions was calculated as the difference in total ozone season anthropogenic NOX emissions between the either the 2016 base case (or the 2028 base case) and the 2023 base case scenario divided by the 2023 base case emission.  Thus, when the 2016 or 2028 base case had smaller emissions than the 2023 base case, the net result was a negative number.  Each state's fractional change in emissions was multiplied by its 2023 base case contribution to get a state- specific change in contribution (Table D-1).  For each monitor, the change in concentrations was summed across all states.  The result was the total "uncalibrated" change in concentration.
 Table D-1. The 2023, 2016, and 2028 Base Cases Total Anthropogenic NOX Emissions with 2023 Ozone Contributions (ppb) and Uncalibrated Contributions for 2016 and 2023 for the Westport Monitor Number 090019003 in Fairfield County, Connecticut.
                                     State
                         2023 Base Case NOX Emissions
                         2016 Base Case NOX Emissions
                         2028 Base Case NOX Emissions
       Fraction of 2016 Base Case Emissions to 2023 Base Case Emissions
       Fraction of 2028 Base Case Emissions to 2023 Base Case Emissions
                      2023 Base Case Ozone Contributions
                Uncalibrated Change in AQ Contribution for 2016
                Uncalibrated Change in AQ Contribution for 2028
                        Uncalibrated Contribution 2016
                        Uncalibrated Contribution 2028
                                      AL
                                                                         67,839
                                                                        101,168
                                                                         60,574
                                                                          0.491
                                                                         -0.107
                                                                          0.113
                                                                          0.056
                                                                         -0.012
                                                                          0.169
                                                                          0.101
                                      AZ
                                                                         45,043
                                                                         70,225
                                                                         37,041
                                                                          0.559
                                                                         -0.178
                                                                          0.016
                                                                          0.009
                                                                         -0.003
                                                                          0.025
                                                                          0.013
                                      AR
                                                                         46,552
                                                                         68,756
                                                                         40,093
                                                                          0.477
                                                                         -0.139
                                                                          0.176
                                                                          0.084
                                                                         -0.024
                                                                          0.259
                                                                          0.151
                                      CA
                                                                        145,157
                                                                        212,134
                                                                        133,619
                                                                          0.461
                                                                         -0.079
                                                                          0.035
                                                                          0.016
                                                                         -0.003
                                                                          0.051
                                                                          0.032
                                      CO
                                                                         61,473
                                                                         86,684
                                                                         55,852
                                                                          0.410
                                                                         -0.091
                                                                          0.065
                                                                          0.027
                                                                         -0.006
                                                                          0.091
                                                                          0.059
                                      CT
                                                                         12,724
                                                                         18,874
                                                                         11,227
                                                                          0.483
                                                                         -0.118
                                                                          2.682
                                                                          1.296
                                                                         -0.316
                                                                          3.979
                                                                          2.367
                                      DE
                                                                          6,985
                                                                         10,193
                                                                          6,274
                                                                          0.459
                                                                         -0.102
                                                                          0.425
                                                                          0.195
                                                                         -0.043
                                                                          0.620
                                                                          0.382
                                      DC
                                                                          1,610
                                                                          2,338
                                                                          1,348
                                                                          0.453
                                                                         -0.163
                                                                          0.041
                                                                          0.019
                                                                         -0.007
                                                                          0.060
                                                                          0.035
                                      FL
                                                                        114,045
                                                                        186,866
                                                                         99,721
                                                                          0.639
                                                                         -0.126
                                                                          0.075
                                                                          0.048
                                                                         -0.009
                                                                          0.123
                                                                          0.065
                                      GA
                                                                         73,702
                                                                        115,451
                                                                         65,044
                                                                          0.566
                                                                         -0.117
                                                                          0.165
                                                                          0.093
                                                                         -0.019
                                                                          0.258
                                                                          0.146
                                      ID
                                                                         19,924
                                                                         29,416
                                                                         16,389
                                                                          0.476
                                                                         -0.177
                                                                          0.028
                                                                          0.013
                                                                         -0.005
                                                                          0.041
                                                                          0.023
                                      IL
                                                                        103,625
                                                                        143,831
                                                                         93,027
                                                                          0.388
                                                                         -0.102
                                                                          0.798
                                                                          0.310
                                                                         -0.082
                                                                          1.107
                                                                          0.716
                                      IN
                                                                         82,323
                                                                        129,702
                                                                         73,428
                                                                          0.576
                                                                         -0.108
                                                                          1.239
                                                                          0.713
                                                                         -0.134
                                                                          1.952
                                                                          1.105
                                      IA
                                                                         48,818
                                                                         67,053
                                                                         41,876
                                                                          0.374
                                                                         -0.142
                                                                          0.169
                                                                          0.063
                                                                         -0.024
                                                                          0.232
                                                                          0.145
                                      KS
                                                                         69,568
                                                                         91,022
                                                                         61,361
                                                                          0.308
                                                                         -0.118
                                                                          0.129
                                                                          0.040
                                                                         -0.015
                                                                          0.168
                                                                          0.114
                                      KY
                                                                         51,946
                                                                         88,409
                                                                         45,953
                                                                          0.702
                                                                         -0.115
                                                                          0.854
                                                                          0.599
                                                                         -0.098
                                                                          1.453
                                                                          0.755
                                      LA
                                                                        105,245
                                                                        138,804
                                                                         98,692
                                                                          0.319
                                                                         -0.062
                                                                          0.266
                                                                          0.085
                                                                         -0.017
                                                                          0.351
                                                                          0.250
                                      ME
                                                                         13,132
                                                                         19,133
                                                                         11,619
                                                                          0.457
                                                                         -0.115
                                                                          0.007
                                                                          0.003
                                                                         -0.001
                                                                          0.010
                                                                          0.006
                                      MD
                                                                         27,785
                                                                         43,974
                                                                         24,694
                                                                          0.583
                                                                         -0.111
                                                                          1.181
                                                                          0.688
                                                                         -0.131
                                                                          1.869
                                                                          1.050
                                      MA
                                                                         33,006
                                                                         45,621
                                                                         29,957
                                                                          0.382
                                                                         -0.092
                                                                          0.079
                                                                          0.030
                                                                         -0.007
                                                                          0.110
                                                                          0.072
                                      MI
                                                                         87,686
                                                                        118,418
                                                                         81,141
                                                                          0.350
                                                                         -0.075
                                                                          1.678
                                                                          0.588
                                                                         -0.125
                                                                          2.266
                                                                          1.553
                                      MN
                                                                         63,293
                                                                         89,970
                                                                         53,343
                                                                          0.421
                                                                         -0.157
                                                                          0.188
                                                                          0.079
                                                                         -0.030
                                                                          0.267
                                                                          0.159
                                      MS
                                                                         33,963
                                                                         56,364
                                                                         30,491
                                                                          0.660
                                                                         -0.102
                                                                          0.101
                                                                          0.067
                                                                         -0.010
                                                                          0.168
                                                                          0.091
                                      MO
                                                                         74,595
                                                                        116,616
                                                                         63,863
                                                                          0.563
                                                                         -0.144
                                                                          0.356
                                                                          0.200
                                                                         -0.051
                                                                          0.556
                                                                          0.305
                                      MT
                                                                         28,901
                                                                         40,605
                                                                         24,884
                                                                          0.405
                                                                         -0.139
                                                                          0.075
                                                                          0.030
                                                                         -0.010
                                                                          0.105
                                                                          0.064
                                      NE
                                                                         43,475
                                                                         59,121
                                                                         37,771
                                                                          0.360
                                                                         -0.131
                                                                          0.076
                                                                          0.028
                                                                         -0.010
                                                                          0.104
                                                                          0.066
                                      NV
                                                                         19,070
                                                                         30,601
                                                                         15,844
                                                                          0.605
                                                                         -0.169
                                                                          0.012
                                                                          0.007
                                                                         -0.002
                                                                          0.020
                                                                          0.010
                                      NH
                                                                          7,763
                                                                         11,753
                                                                          6,806
                                                                          0.514
                                                                         -0.123
                                                                          0.018
                                                                          0.009
                                                                         -0.002
                                                                          0.028
                                                                          0.016
                                      NJ
                                                                         37,738
                                                                         58,456
                                                                         33,624
                                                                          0.549
                                                                         -0.109
                                                                          8.446
                                                                          4.637
                                                                         -0.921
                                                                         13.083
                                                                          7.525
                                      NM
                                                                         53,165
                                                                         70,102
                                                                         47,356
                                                                          0.319
                                                                         -0.109
                                                                          0.038
                                                                          0.012
                                                                         -0.004
                                                                          0.051
                                                                          0.034
                                      NY
                                                                         77,766
                                                                        106,248
                                                                         69,004
                                                                          0.366
                                                                         -0.113
                                                                         14.141
                                                                          5.179
                                                                         -1.593
                                                                         19.320
                                                                         12.547
                                      NC
                                                                         76,448
                                                                        101,378
                                                                         64,646
                                                                          0.326
                                                                         -0.154
                                                                          0.548
                                                                          0.179
                                                                         -0.085
                                                                          0.727
                                                                          0.464
                                      ND
                                                                         46,471
                                                                         58,914
                                                                         41,774
                                                                          0.268
                                                                         -0.101
                                                                          0.080
                                                                          0.021
                                                                         -0.008
                                                                          0.101
                                                                          0.071
                                      OH
                                                                         98,579
                                                                        141,543
                                                                         87,637
                                                                          0.436
                                                                         -0.111
                                                                          2.506
                                                                          1.092
                                                                         -0.278
                                                                          3.598
                                                                          2.228
                                      OK
                                                                        101,105
                                                                        120,286
                                                                         92,941
                                                                          0.190
                                                                         -0.081
                                                                          0.195
                                                                          0.037
                                                                         -0.016
                                                                          0.233
                                                                          0.180
                                      OR
                                                                         31,443
                                                                         46,235
                                                                         26,228
                                                                          0.470
                                                                         -0.166
                                                                          0.028
                                                                          0.013
                                                                         -0.005
                                                                          0.041
                                                                          0.023
                                      PA
                                                                        112,449
                                                                        160,648
                                                                        100,275
                                                                          0.429
                                                                         -0.108
                                                                          6.723
                                                                          2.882
                                                                         -0.728
                                                                          9.604
                                                                          5.995
                                      RI
                                                                          4,742
                                                                          6,994
                                                                          4,106
                                                                          0.475
                                                                         -0.134
                                                                          0.010
                                                                          0.005
                                                                         -0.001
                                                                          0.015
                                                                          0.009
                                      SC
                                                                         46,385
                                                                         67,218
                                                                         40,781
                                                                          0.449
                                                                         -0.121
                                                                          0.177
                                                                          0.079
                                                                         -0.021
                                                                          0.256
                                                                          0.155
                                      SD
                                                                         13,753
                                                                         21,784
                                                                         10,688
                                                                          0.584
                                                                         -0.223
                                                                          0.047
                                                                          0.028
                                                                         -0.011
                                                                          0.075
                                                                          0.037
                                      TN
                                                                         57,191
                                                                         89,762
                                                                         50,022
                                                                          0.569
                                                                         -0.125
                                                                          0.318
                                                                          0.181
                                                                         -0.040
                                                                          0.499
                                                                          0.278
                                      TX
                                                                        314,342
                                                                        418,972
                                                                        288,147
                                                                          0.333
                                                                         -0.083
                                                                          0.582
                                                                          0.194
                                                                         -0.049
                                                                          0.776
                                                                          0.534
                                      UT
                                                                         35,868
                                                                         53,661
                                                                         31,932
                                                                          0.496
                                                                         -0.110
                                                                          0.033
                                                                          0.016
                                                                         -0.004
                                                                          0.049
                                                                          0.029
                                      VT
                                                                          4,047
                                                                          6,078
                                                                          3,340
                                                                          0.502
                                                                         -0.175
                                                                          0.014
                                                                          0.007
                                                                         -0.002
                                                                          0.021
                                                                          0.011
                                      VA
                                                                         57,856
                                                                         93,453
                                                                         51,398
                                                                          0.615
                                                                         -0.112
                                                                          1.273
                                                                          0.783
                                                                         -0.142
                                                                          2.057
                                                                          1.131
                                      WA
                                                                         58,962
                                                                         89,605
                                                                         49,093
                                                                          0.520
                                                                         -0.167
                                                                          0.055
                                                                          0.028
                                                                         -0.009
                                                                          0.083
                                                                          0.046
                                      WV
                                                                         53,854
                                                                         61,692
                                                                         52,047
                                                                          0.146
                                                                         -0.034
                                                                          1.459
                                                                          0.212
                                                                         -0.049
                                                                          1.671
                                                                          1.410
                                      WI
                                                                         48,283
                                                                         75,140
                                                                         41,731
                                                                          0.556
                                                                         -0.136
                                                                          0.229
                                                                          0.127
                                                                         -0.031
                                                                          0.357
                                                                          0.198
                                      WY
                                                                         41,098
                                                                         53,908
                                                                         36,966
                                                                          0.312
                                                                         -0.101
                                                                          0.078
                                                                          0.024
                                                                         -0.008
                                                                          0.103
                                                                          0.070
                                    TRIBAL
                                                                          5,858
                                                                         17,759
                                                                          5,875
                                                                          2.032
                                                                          0.003
                                                                          0.004
                                                                          0.009
                                                                          0.000
                                                                          0.013
                                                                          0.004
                                    CAN_MEX

                                                                              0
                                                                              0
                                                                        2.52895
                                                                              0
                                                                              0
                                                                        2.52895
                                                                        2.52895
                                   OFFSHORE

                                                                              0
                                                                              0
                                                                        0.67413
                                                                              0
                                                                              0
                                                                        0.67413
                                                                        0.67413
                                     FIRE

                                                                              0
                                                                              0
                                                                        0.34482
                                                                              0
                                                                              0
                                                                        0.34482
                                                                        0.34482
                                     ICBC

                                                                              0
                                                                              0
                                                                       20.63261
                                                                              0
                                                                              0
                                                                       20.63261
                                                                       20.63261
                                     BIOG

                                                                              0
                                                                              0
                                                                        4.68736
                                                                              0
                                                                              0
                                                                        4.68736
                                                                        4.68736
	Next, the estimate of the monitor specific ozone responses under the 2016 or 2028 base cases was used to calibrate the ozone AQAT to CAMx and to derive the calibration factors.  One factor was created using the 2016 base and is applied to all scenarios from 2016 through 2022, the other factor was created using the 2028 base and is applied to all scenarios from 2023 to 2028.  First, the changes in ozone predicted by the ozone AQAT and CAMx for the average design values were calculated for each monitor for the 2016 or 2028 base case relative to the 2023 base case concentrations.  The change in ozone predicted by CAMx was then divided by the change in ozone predicted by the uncalibrated AQAT, resulting in a monitor-specific calibration factor (see Table D-2 for an example calculation using the 2016 and 2028 base cases).  The calculation of these monitor-specific calibration factors provided EPA with the ability to align the ozone response predicted by the ozone AQAT to the ozone response predicted by CAMx.
      The ozone AQAT and CAMx concentration differences can be found in the "Ozone AQAT_Final.xlsx" excel workbook in columns BK and BL, respectively, on worksheets "calib_2016" and "calib_2028". The resulting calibration factors can be found in column BM of the aforementioned excel worksheets.  The calibration factor, multiplied by the fractional change in emissions (relative to the 2023) base and multiplied by the 2023 base air quality contribution, results in the fractional change in air quality contribution for any alternative scenario.

Table D-2. Design Values in the 2023 Base Case and the 2016 and 2028 Base Cases and Estimated Change in Design Value Relative to the 2023 Base Case from CAMx and Uncalibrated AQAT for the Westport Monitor Number 090019003 in Fairfield County, Connecticut.

                       2023 Base Case Concentration (ppb)
                       2016 Base Case Concentration (ppb)
                       2028 Base Case Concentration (ppb)
                   Change in Concentration from 2016 to 2023
                                     (ppb)
                   Change in Concentration from 2028 to 2023
                                     (ppb)
 CAMx
                                                                          76.90
                                                                          82.70
                                                                          74.30
                                                                           5.80
                                                                          -2.60
 Uncalibrated AQAT
                                                                          76.90
                                                                          98.04
                                                                          71.70
                                                                          21.14
                                                                          -5.20
 Calibration Factor  -  Change in Concentration from CAMx Divided by Change in Concentration from the Uncalibrated AQAT

                                                                         0.2743
                                                                         0.4998

(2) Create a calibrated version of the ozone AQAT for emission budget analysis for the proposed rule

      Next, as was done at proposal, EPA used 2023 base case emissions and 2023 base case air quality ozone contributions from the air quality modeling along with either the 2016-based or 2028-based calibration factors to create a "calibrated" AQAT specific to the year being assessed.  EPA examined the changes in the 2023 air quality contributions from changes in emissions relative to the 2023 base case emissions (while using the calibration factor).  This calibrated AQAT was then used to estimate the change in predicted ozone due to NOX emission reductions under each emission cost threshold level evaluated for EGUs and non-EGUs in each year.
      First, as described in section VI of the preamble and above in section C of this TSD for EGUs, EPA identified various cost threshold levels of emissions based on projected changes in emissions rates and adjusted historical data.  For each state, for each year, the total anthropogenic NOx emissions (excluding the EGU emissions) are presented in Table D-3.  These "straight line" emissions inventories were created by linearly interpolating the emissions for all anthropogenic source sectors except EGUs between 2023 and 2016 (or between 2023 and 2028).  An additional set of sensitivity analyses were done for 2021 and 2022 using the 2021 emission inventory directly and by linearly interpolating the emissions for all source sectors (except EGUs) between the 2021 and 2023 inventories.
      The EGU point inventory is composed of emissions from units that report emissions to EPA's Clean Air Markets Division (CAMD) under 40 CFR Part 75 (most emissions from these sources are measured by CEMS) and units that are typically included in EPA's power sector modeling using the Integrated Planning Model (IPM) but that do not report to CAMD and typically lack CEMS (i.e., the nonCEM units).  Within the air quality modeling platform, different approaches are taken depending on whether an emissions inventory for EGUs is created using an IPM-based emission estimates or an engineering analysis based platform.  The nonCEM components for various air quality model platforms are shown in Table D-4.  For each year, based on the available air quality modeling runs available (in 2016, 2023, and 2028) an engineering-based nonCEM point EGU component was created (Table D-5).  For the years from 2016 through 2023, this was a straight line linear interpolation of the 2016 and 2023 nonCEM component from the engineering based air quality runs.  For years 2023 through 2028, we used 2023 nonCEM values held constant for all years.  The component of the EGU point inventory from CAMD reporting units (labelled "CEMs") was developed using engineering analysis (see section C for details).   For each year, we show EGU emissions for units with CEMs as a function of cost threshold level (see Tables C-1 through C-5 for the years 2021 through 2025, respectively).  These levels include:
 Engineering Baseline,
 $500/ton,
 Optimize SCR,
 Optimize SCR + State-of-the-Art Combustion Controls (referred to as Low NOx Burners, or LNB),
 Optimize SNCR+ SCR ,
 Optimize SNCR+ SCR + LNB ,
 New SNCR + Optimize SNCR+ SCR + LNB
 New SCR + Optimize SNCR+ SCR + LNB.

      In the construction of AQAT, for each scenario, we assembled an emission inventory from all anthropogenic sources for each state.  In other words, we combine the year-specific anthropogenic emissions from Table D-3, with the relevant EGU nonCEM component from D-5, and one of the EGU CEM estimates from Tables C-1 through C-5.
      Finally, these emission totals are compared to the 2023 case that was modeled with CAMx.  For each emission cost threshold level in each analysis year, EPA calculated the ratio of the emission differences from the scenario and the 2023 air quality modeling base case to the total NOX emissions for the 2023 air quality modeling base case used in the air quality modeling for each state (see Tables D-6 through D-10). Scenarios that are not viable, for technical or policy reasons, have been grayed out in these tables.
      For each year, we also created a complete "straight line" emissions inventory including a linear interpolation of the EGU inventory from the air quality modeling between 2023 and 2016 and between 2023 and 2028.  For the sensitivity analysis, the interpolation was between 2021 and 2023.  The emission differences and air quality estimates for the two sensitivity scenarios can be found in Appendix H.  In Table D-11, we examined the emission reduction for non-EGUs in tranche 1 for glass and cement controls below $2,000 per ton, and then estimated the ratio of the emission difference relative to the 2023 air quality modeling base case.
      For each cost threshold level analyzed, on a receptor-by-receptor basis, the emissions change for each upwind state is associated with one of two emission levels (either the engineering base case emission level for that year or the particular cost threshold level) depending on whether the upwind state is "linked" to that receptor or if the receptor is located within the state.  States that are contributing above the air quality threshold (i.e., greater than or equal to 1 percent of the NAAQS) to the monitor, as well as the state containing the monitor, make NOX emission reductions available at the particular cost threshold level for that year.  The emissions for all other states are adjusted to the engineering base case level for that year.
      For the $1,800/ton control case at various years, all states that were linked to any receptor in 2021 were simultaneously adjusted to the emission levels in the control case, regardless of whether (or not) the state was "linked" to a particular receptor.  This scenario examines the emission results when budgets have been applied to the geography. For each monitor, the predicted  change in contribution of ozone from each state is calculated by multiplying the state-specific 2023 base case ozone contributions from the air quality modeling by the calibration factor as well as by the ratio of the change in emissions (Tables D-1 and D-6 through D-10, for either the emission cost threshold level or the engineering base case emission level depending on whether the state is linked).  This calibrated change in ozone is then added to the ozone contribution from the 2023 base case air quality modeling.  The result is the state and receptor specific "calibrated" total ozone contribution after implementation of the emission at a particular cost threshold level.
      For each monitor, these state-level "calibrated" contributions are then summed to estimate total ozone contribution from the states to a particular receptor in the CAMx modeling domain.  Finally, "other" modeled ozone contributions ("CAN_MEX", "OFFSHORE", "USCANMEX_FIRE",  "ICBC", and "BIOG") are added from the 2023 base case air quality modeling to the state contributions to account for other sources of ozone affecting the modeling domain.  The total ozone from all the states and "other" contributions equals the average design values estimated in the assessment tool.  The maximum design values were estimated by multiplying the estimated average design values by the ratio of the modeled 2023 base case maximum to average design values.
      Generally, as the emission cost threshold stringency increased, the estimated average and maximum design values at each receptor decreased.  In the assessment tool, the estimated value of the average design value was used to estimate whether the location will be out of attainment, while the estimated maximum design value was used to estimate whether the location will have problems maintaining the NAAQS.  The area was noted as having a nonattainment or maintenance issue if either estimated air quality level was greater than or equal to 76 ppb.

Table D-3.  Ozone Season Anthropogenic NOX Emissions (Tons) without EGUs for Each State.
                                     State
                                     2021
                                     2022
                                     2023
                                     2024
                                     2025
                                     2026
                               2021 Sensitivity
                               2022 Sensitivity
Alabama
                                                                        69,987
                                                                        66,163
                                                                        62,338
                                                                        60,603
                                                                        58,868
                                                                        57,134
                                                                        66,126
                                                                        64,232
Arizona
                                                                        45,793
                                                                        42,719
                                                                        39,644
                                                                        38,220
                                                                        36,796
                                                                        35,371
                                                                        42,094
                                                                        40,869
Arkansas
                                                                        42,259
                                                                        39,586
                                                                        36,914
                                                                        35,793
                                                                        34,672
                                                                        33,551
                                                                        40,275
                                                                        38,594
California
                                                                       161,697
                                                                       152,246
                                                                       142,795
                                                                       140,823
                                                                       138,852
                                                                       136,880
                                                                       155,951
                                                                       149,373
Colorado
                                                                        59,562
                                                                        56,774
                                                                        53,986
                                                                        52,934
                                                                        51,881
                                                                        50,829
                                                                        55,717
                                                                        54,852
Connecticut
                                                                        12,579
                                                                        11,683
                                                                        10,787
                                                                        10,496
                                                                        10,205
                                                                         9,914
                                                                        11,598
                                                                        11,193
Delaware
                                                                         7,443
                                                                         7,053
                                                                         6,664
                                                                         6,514
                                                                         6,365
                                                                         6,216
                                                                         7,046
                                                                         6,855
District of Columbia
                                                                         1,817
                                                                         1,713
                                                                         1,609
                                                                         1,556
                                                                         1,504
                                                                         1,452
                                                                         1,678
                                                                         1,643
Florida
                                                                       113,717
                                                                       105,687
                                                                        97,657
                                                                        94,900
                                                                        92,143
                                                                        89,385
                                                                       101,801
                                                                        99,729
Georgia
                                                                        77,170
                                                                        71,638
                                                                        66,107
                                                                        64,178
                                                                        62,248
                                                                        60,319
                                                                        71,469
                                                                        68,788
Idaho
                                                                        22,332
                                                                        21,039
                                                                        19,745
                                                                        19,039
                                                                        18,333
                                                                        17,627
                                                                        21,057
                                                                        20,401
Illinois
                                                                       103,427
                                                                        98,260
                                                                        93,094
                                                                        90,938
                                                                        88,782
                                                                        86,626
                                                                        97,378
                                                                        95,236
Indiana
                                                                        73,016
                                                                        68,763
                                                                        64,511
                                                                        62,670
                                                                        60,829
                                                                        58,988
                                                                        69,443
                                                                        66,977
Iowa
                                                                        42,556
                                                                        39,903
                                                                        37,250
                                                                        35,915
                                                                        34,580
                                                                        33,246
                                                                        40,668
                                                                        38,959
Kansas
                                                                        67,361
                                                                        64,151
                                                                        60,941
                                                                        59,345