EPA disagrees with the commenter and finds that its analyses for the final rule are sufficiently detailed and precise enough to support the Agency's determinations of emission reduction responsibilities in each state.  EPA has followed all of its own modeling guidance to states and has employed analytic methodologies (using peer-reviewed models) that have been upheld in prior regulatory actions under judicial review.  The commenter's assertions ignore commonly practiced and widely accepted regulatory development procedures and demonstrate fundamental misunderstandings of the role of these analyses in Clean Air Act rulemakings.  The interstate contributions to PM2.5 calculated for the Transport Rule are based on all anthropogenic emissions of SO2 and NOx, not just those emissions from the power sector.  Thus, considering the variability in power sector emissions alone, as suggested by the commenter, would not provide a meaningful approach to characterizing the uncertainty in the predicted contributions.  In addition, the approach suggested by the commenter of using expert elicitation is not workable in view of the construct of air quality modeling systems and the lack of data to gauge the uncertainty in individual components of this system.  As noted by the NRC, air quality modeling systems are quite complex.  They include hundreds of different emission sources, multiple, hourly spatially varying weather parameters (e.g., winds, mixing, clouds, precipitation, temperature, etc.), non-linear photochemical reactions, pollutant-specific, land-use and weather-dependent removal by deposition as well as other physical factors that affect the formation, transport, and ultimate fate of ozone and the individual component species of PM2.5 (e.g., sulfate, nitrate, organic carbon, etc.).   We are unaware of any expert or group of experts that would be able to provide a factual determination of the uncertainty in each and every component of the modeling system and then assimilate all of this disparate information in a physically and chemically consistent and sound manner that would provide a meaningful quantitative estimate of the overall uncertainty in the air quality modeling system.  For the final Transport Rule, EPA used a state-of-the science, "one atmosphere" air quality model, CAMx, with peer-reviewed source apportionment techniques coupled with input data that have undergone external review, and evaluation and analysis methods that are consistent with recommendations by the NRC.  Thus, EPA believes that the Transport Rule air quality modeling system is capable of fully supporting decisions made as part of this rule.
Organization: Iowa Department of Natural Resources (IDNR)
Comment:
Iowa Department of Natural Resources (IDNR)
We commend EPA for using current state of the science tools for assessing interstate contributions such as the use of source apportionment technologies available in the CAMx photochemical grid model. Scientifically sound and technically supported methods are necessary components of the process to build the justification of any rule addressing intestate pollutant transport. Implementation of source apportionment methods can provide consistent, reproducible, and justifiable means through which source and receptor linkages can be evaluated. [EPA-HQ-OAR-2009-0491-2609.1, p.2]
Response:
EPA agrees that the air quality modeling approach and models used for the Final Transport Rule are state-of-the-science and appropriate for use in this rule.
Organization: Kansas Department of Health and Environment
Comment:
Kansas Department of Health and Environment
In our review of the proposal, we support many of the technical approaches EPA has used to determine contributions to nonattainment, specifically the use of 'best science' tools such as CAMx with source apportionment. KDHE believes tools such as CAMx can provide valuable insights into culpability assessments if proper inputs are used and correct interpretations are made. It appears EPA is making an attempt to utilize the latest available emissions and tools to inform policy decisions, and we commend EPA for this. [EPA-HQ-OAR-2009-0491-2606.1, p.2]
Response:
EPA agrees that the air quality modeling approach and models used for the Final Transport Rule are state-of-the-science and appropriate for use in this rule.
Organization: Maryland Department of Environment (MDE)
Comment:
Maryland Department of Environment (MDE)
Guidance on model performance for transport. EPA is now using photochemical modeling to determine significant contribution in the Transport Rule. Our research has shown that in the past, some of the photochemical models did not capture aloft transport from the west and low level jet transport from the south accurately. It is critical, with the models now being asked to play a critical role in addressing transport, that the model performance for transport be adequate. Maryland believes that EPA needs to address this issue in its modeling guidance. See Appendix A [See EPA-HQ-OAR-2009-0491-2639.2, p.22 for comments pertaining to Appendix A] for more information on the Maryland research program. [EPA-HQ-OAR-2009-0491-2639.2, p.6]
Response:
EPA has completed an expanded model performance evaluation using the predictions from the updated 2005 base year CAMx simulation conducted for the final Transport Rule.   This evaluation provides additional spatial and temporal performance results in response to comments.  The model performance results can be found in Appendix A of the Final Transport Rule Air Quality Modeling Technical Support Document.  Including guidance on model performance for transport as part of EPA's modeling guidance for attainment demonstrations is outside the scope of this rulemaking.   The Final Transport Rule requires emissions reductions of annual NOx and/or ozone season NOx in 27 states in the East in addition to Maryland.  This includes states that are 700 miles to the south of Maryland and 1000 miles to the west of Maryland.  The emissions reductions within these upwind states will help Maryland attain and maintain the 1997 ozone NAAQS.
Organization: Midwest Ozone Group
Comment:
Midwest Ozone Group
Modeling of existing CAIR requirements and other OTB controls indicate no needfor the nature and extent of controls as proposed in the CATR. [EPA-HQ-OAR-2009-0491-2809.1, p.9]
In support of its position that EPA's CATR analysis is flawed because it excludes benefits of controls installed on the EGU fleet since 2005, MOG and other entities have sponsored an analysis of the impact on predicted ozone and PM2.5 nonattainment resulting from emissions reductions that have occurred since 2005 as a result of the installation of additional controls, including controls that resulted from the CAIR. The studies, also included in the attachment to these comments, were performed using the CAMx model by Alpine Geophysics and included projections of predicted 2014 and 2018 air quality. They include modeling scenarios called "2014 Business As Usual (BAU)" and "2018 BAU." A disc with the input and output files related to these studies is being submitted under separate cover. [EPA-HQ-OAR-2009-0491-2809.1, p.9]
The project also involved use of updated inputs to the CAMx model, including a projected 2014 EGU inventory compiled by James Marchetti, J. Edward Cichanowicz and Michael Hein, and a projected non-EGU inventory compiled by Alpine Geophysics. [EPA-HQ-OAR-2009-0491-2809.1, p.9]
Alpine Geophysics conducted photochemical modeling analyses, including the EPA attainment test, for three key years: 2008, 2014, and 2018. The modeling for year 2008 served the important function of providing a recent `typical baseline' year for the purpose of calculating relative reduction factors (RRFs). Most importantly, moving to 2008 took direct advantage of recent reductions in 8-hr design values measured across the modeling region. Results of this work clarify when the effects of BAU state and federal control programs would begin to significantly lower the 8-hr ozone and annual and 24-hr PM2.5 design values at key monitors in the modeling domain. [EPA-HQ-OAR-2009-0491-2809.1, p.10]
The SO2 and NOx emission forecast for this analysis assumed compliance with the CAIR, as well as utility agreements with regard to consent decrees and state programs. The future regional electrical generation by fuel type and regional fuel forecasts that were incorporated into the model were from the Energy Information's Administration's Annual Energy Outlook 2009 (AEO2009) - Updated Reference Case. [EPA-HQ-OAR-2009-0491-2809.1, p.10]
Using EPA attainment test software and algorithms with the output from the BAU CAMx simulations for 2008, 2014 and 2018, Alpine Geophysics concludes that the ozone objectives of the proposed CATR can be achieved no later than 2014 within the 12 km modeling domain with no new controls beyond the existing CAIR and other BAU requirements. [EPA-HQ-OAR-2009-0491-2809.1, p.10]
Alpine Geophysics also concludes that the annual PM2.5 objectives of the proposed transport rule can be achieved no later than 2014 within the 12 km modeling domain with no new controls beyond the existing CAIR and other BAU requirements, with the possible exception of additional local controls at the Allegheny County, PA location, discussed later in these comments. [EPA-HQ-OAR-2009-0491-2809.1, p.10]
Finally, Alpine Geophysics concludes that the 24-hr PM2.5 objectives of the proposed CATR can be achieved within the 12 km modeling domain no later than 2014 with no new controls beyond the existing CAIR and other BAU requirements, with the possible exception of additional local controls at the Allegheny County, PA and Brooke County, WV locations, which are discussed later in these comments. [EPA-HQ-OAR-2009-0491-2809.1, p.10]
Accordingly, the additional stringent emission reductions EPA is proposing in the CATR are not needed to achieve the air quality objective EPA is targeting - attainment of the subject NAAQS requirements. [EPA-HQ-OAR-2009-0491-2809.1, p.10]
Response:
See section V.C.2 of the preamble.
Organization: New York State Department of Environmental Conservation
Comment:
New York State Department of Environmental Conservation
The evaluation of the CAMx base case performance presented in the Air Quality Modeling Technical Support Document (AQM-TSD) is limited to an operational evaluation of ozone and PM2.5 species using standard statistical comparisons. While these comparisons indicate model performance that is generally within the range of previous studies, they do not establish the modeling system's ability to capture the physical and chemical processes relevant to interstate transport of air pollution. In addition, these evaluations do not establish the modeling system's ability to correctly quantify the impact of emission reductions on ambient concentrations. For example, how did the model perform during high pollution events when interstate transport is considered to play a major role? Finally, the very high bias for the crustal/other component raises questions about the quality of the emission inventory for primary PM2.5 and/or the CAMx representation of its transport and removal. [EPA-HQ-OAR-2009-0491-2730.1, p.11]
Response:
EPA has completed an expanded model performance evaluation using the predictions from the updated 2005 base year CAMx simulation conducted for the final Transport Rule.   This evaluation provides additional spatial and temporal performance results in response to comments.  The model performance results can be found in Appendix A of the Final Transport Rule Air Quality Modeling Technical Support Document.

Organization: Progress Energy Service Company
Omaha Public Power District
Nebraska Public Power District
Comment:
Nebraska Public Power District
10) Monitored-Plus-Modeled Approach. EPA should not have abandoned use of the "monitored-plus-modeled" approach that it used in CAIR to determine downwind nonattainment areas to be addressed. EPA provides no justification for its decision to jettison this approach. The monitored-plus-modeled approach helps provide grounding in real-world air quality that is lost in EPA's novel "modeling-only" approach. The use of monitored data was not challenged or criticized in North Carolina v. EPA. Hence, there is no need to alter this approach. [EPA-HQ-OAR-2009-0491-2711.1, p.8]
Omaha Public Power District
EPA should not have abandoned use of the 'monitored-plus-modeled' approach that it used in CAIR to determine downwind nonattainment areas to be addressed. EPA provides no justification for its decision to jettison this approach. The monitored-plus-modeled approach helps provide grounding in real-world air quality that is lost in EPA's novel 'modeling-only' approach. The use of monitored data was not challenged or criticized in North Carolina v. EPA. Hence, there is no need to alter this approach. [EPA-HQ-OAR-2009-0491-2680.1, p. 5]
Progress Energy Service Company
EPA should not have abandoned the use of the 'monitored-plus-modeled' approach that it used in developing the CAIR to determine downwind nonattainrnent areas be addressed. EPA provides no justification for its decision to jettison this approach. The monitored-plus-modeled approach is preferable to the approach used in the proposed Transport Rule because the inclusion of monitored data helps provide a basis in real-world air quality that is lost in EPA's 'modeling only' approach. Moreover, the use of monitored data was not challenged or criticized in North Carolina v. EPA. [EPA-HQ-OAR-2009-0491-2831.1 p.6]
Response:
See section V.C.2 of the preamble.
Organization: Southern Company
Comment:
Southern Company
EPA's method eliminated the monitored-plus-modeled test for identifying downwind (and now maintenance) monitors for assessment that was used in CAIR. This change removes an important constraint on the use of uncertain models. EPA's method ignored real emissions reductions from CAIR (still in place and operating) and local SIP-related controls, this omission leads to an overestimate of projected nonattainment/maintenance. EPA's method ignored its own regulatory modeling guidance by not properly projecting future air quality, especially for urban areas with strong local source contributions. For such situations, EPA guidance for evaluating air quality requires the use of refined models such as AERMOD joined with CMAQ for PM2.5, or a 4 km or less horizontal resolution receptor grid and/or plume-in-grid treatment for ozone. Collectively, the EPA approach results in over predictions of future air quality concentrations and over predictions of the number of significant air quality contribution linkages, thereby inflating the air quality burden to be 'resolved.' [EPA-HQ-OAR-2009-0491-2864.1, p. 30]
D. EPA's Refined Air Quality Modeling Fails to Follow its Own Guidance for Application and Performance Evaluation
EPA applied the CAMx model and its OSAT and PSAT source apportionment tools. There are serious problems with their application of these tools that begs the credibility of their analysis. [EPA-HQ-OAR-2009-0491-2864.1, p. 32]
First, EPA failed to apply their own guidance in modeling for PM2.5 in urban areas, especially where local sources have a significant short-range effect on the monitors (e.g., the North Birmingham and Wylam PM2.5 monitors in Birmingham both have significantly elevated concentrations compared to nearby urban monitors, largely due to local sources). EPA guidance recommends the use of AERMOD in conjunction with CMAQ (or CAMx) to obtain a more accurate projection of air quality. EPA did not do this nor otherwise try to account for effects of local sources in their projections. By ignoring this issue, EPA has likely overestimated future air quality concentrations, thereby increasing the air quality 'burden' that must be resolved, especially since EPA requires attainment and maintenance to be achieved through this rule, a criteria that is both overly burdensome and unlawful. [EPA-HQ-OAR-2009-0491-2864.1, p. 32]
Second, EPA's model performance evaluation is cursory at best. State SIP demonstrations require model performance evaluations that are far more rigorous. Further, EPA does not even use actual historical EGU emissions to assess how well the air quality model predicts actual historical monitored data. They use 'typical' EGU emissions. This process for model evaluation is totally unacceptable. In a model performance assessment, actual historical emissions must be used in the modeling or else the comparison of air quality modeling predictions to actual historical monitored data has no meaning. [EPA-HQ-OAR-2009-0491-2864.1, p. 32]
Third, given the importance of the PSAT and OSAT tools, EPA should have done much more to demonstrate that the tools give reliable answers, especially since they are being used to assess such small thresholds. A similar demonstration is needed for their use of the CAMx model itself. Can these models and source apportionment tools really give accurate results at differences of 0.15 ug/m3 of PM and 0.8 ppb of ozone? [EPA-HQ-OAR-2009-0491-2864.1, p. 32]
Finally, since EPA's approach is to rely solely on the model to determine if a monitor is in nonattainment or has a maintenance issue, getting the air quality projection correct is critical. EPA cannot reasonably argue that the use of coarse-scale modeling is acceptable for 'transport' but that 'local' effects are not relevant. The ultimate stringency of the proposed rule is critically dependent on getting projected air quality correct, and getting the local contribution correct is an essential element. [EPA-HQ-OAR-2009-0491-2864.1, p. 33]
The role of NOx in particulate matter formation is further complicated by recent discoveries demonstrating that the production of biogenic secondary organic aerosol (SOA) is heavily influenced by NOx levels. Specifically, this research shows that that biogenic SOA, particularly for isoprene, is enhanced with lower NOx levels due to changes in the fate of peroxy radicals. Thus, NOx reductions, particularly in the Southeast which has significant biogenic emissions, could actually result in increased PM2.5. Air quality models at present do not include this newly discovered chemistry and, therefore, EPA's analysis does not take into account these potential NOx disbenefits. In addition, the proper simulation of ammonium nitrate and other nitrate aerosol (e.g., organic nitrates) has confounded air quality scientists for many years. As such, the representation of the impacts NOx emission changes in PM levels in these models is incomplete, particularly when attempting to simulate relatively small signals such as interstate contributions to PM. [EPA-HQ-OAR-2009-0491-2864.1, p. 45]
Response:
See preamble section V.C.2 for response to comments on (1) use of monitored-plus-modeled approach and (2) applicability of local scale modeling for determining future nonattainment as part of the Transport Rule.
EPA has completed an expanded model performance evaluation using the predictions from the updated 2005 base year CAMx simulation conducted for the final Transport Rule.   The 2005 simulation used for the performance evaluation includes year-specific emissions from EGU and onroad and nonroad mobile sources.  The evaluation provides additional spatial and temporal performance results in response to comments.  The model performance results can be found in Appendix A of the Final Transport Rule Air Quality Modeling Technical Support Document.
 The commenter says that EPA should have done much more to demonstrate that the PSAT and OSAT tools give reliable answers.  However, the commenter does not provide any suggestions on what might be included in such a demonstration.  EPA has subjected the PSAT and OSAT tools to an independent peer review.  Both OSAT and PSAT received favorable comments. "All reviewers agreed that OSAT in CAMx is a mature and well-evaluated methodology" and the "PSAT source apportionment technique has been extensively tested and evaluated against other source apportionment techniques". [Arunachalam, S. Peer Review of Source Apportionment Tools in CAMx and CMAQ, EP-D-07-102. University of North Carolina, Institute for the Environment, August 2009.]
 The comments related to the current understanding of the impact of NOx on biogenic SOA and the simulation of ammonium nitrate do not reflect the state-of-the-science and noticeably lack supporting references.  While earlier studies (e.g., Kroll et al., 2006) reported increases in SOA associated with decreases in NOx from the isoprene-plus-OH pathway, recent work (e.g., Chan et al., 2010) suggests that SOA production from isoprene oxidation by OH can be similar for high- and low-NOx conditions at atmospherically relevant NO2-to-NO  ratios.  Additionally, a recent study (Ng et al., 2008) suggests that increases in biogenic SOA could be associated with increases in NOx via the isoprene-plus-NO3 radical pathway.  Furthermore, Ng et al. (2007) have reported increases in biogenic SOA associated with increases in NOx for the sesquiterpene-plus-OH pathway.  Therefore, even if a "dis-benefit" in biogenic SOA formation via the isoprene-plus-OH pathway occurred under reduced-NOx conditions, it could be compensated for by a potential "benefit" in biogenic SOA reduction via other pathways (e.g., sesquiterpenes-plus-OH, isoprene-plus-nitrate radical).  Indeed, a preliminary global modeling study that accounts for benefit and disbenefit pathways suggests that their impacts may largely cancel in the Southeast US (Pye et al., 2010).  While the dependence of biogenic SOA formation on NOx levels is an area of ongoing research, the current literature does not implicate a significant dis-benefit of biogenic SOA formation in the Southeast US associated with reductions in NOx concentration.
 EPA disagrees with the comment that the simulation of ammonium nitrate aerosol confounds air quality scientists.  The thermodynamic and dynamic processes governing ammonium nitrate aerosol formation have been understood for many years (e.g., Bassett and Seinfeld, 1983; Wexler and Seinfeld, 1990, 1991).  The early challenge to representing ammonium nitrate formation in 3D photochemical models was related to the computationally intensive nature of the calculations rather than unknown chemical and physical processes.  However, thermodynamic modules were developed in the 1990s to efficiently solve the inorganic thermodynamic aerosol problem (e.g., ISORROPIA; Nenes et al., 1998).  Current state-of-the-science photochemical models, including CAMx, contain such thermodynamic modules.
References:
Bassett, ME, and Seinfeld, JH (1983) Atmospheric equilibrium model of sulphate and nitrate aerosols, Atmospheric Environment 17:2237 - 2252.
Chan, AWH, Chan, MN, Surratt, JD, Chhabra, PS, Loza, CL, Crounse, JD, Yee, LD, Flagan, RC, Wennberg, PO, and Seinfeld, JH (2010) Role of aldehyde chemistry and NOx concentrations in secondary organic aerosol formation. Atmospheric Chemistry and Physics 10(15): 7169-7188.
Foley, KM, Roselle, SJ, Appel, KW, Bhave, PV, Pleim, JE, Otte, TL, Mathur, R, Sarwar, G, Young, JO, Gilliam, RC, Nolte, CG, Kelly, JT, Gilliland, AB, and Bash, JO (2010) Incremental testing of the Community Multiscale Air Quality (CMAQ) modeling system version 4.7. Geoscientific Model Development 3:205 - 226.
Kroll, JH, Ng, NL, Murphy, SM, Flagan, RC, and Seinfeld, JH (2006) Secondary organic aerosol formation from isoprene photooxidation. Environmental Science & Technology 40(6): 1869-1877.
Nenes, A, Pandis, SN, and Pilinis, C, (1998) ISORROPIA: a new thermodynamic equilibrium model for multiphase multicomponent inorganic aerosols. Aquatic Geochemistry 4(1):123 - 152.
Ng, NL, Chhabra, PS, Chan, AWH, Surratt, JD, Kroll, JH, Kwan, AJ, McCabe, DC, Wennberg, PO, Sorooshian, A, Murphy, SM, Dalleska, NF, Flagan, RC, and Seinfeld, JH (2007) Effect of NOx level on secondary organic aerosol (SOA) formation from the photooxidation of terpenes. Atmospheric Chemistry and Physics 7:5159 - 5174.
Ng, NL, Kwan, AJ, Surratt, JD, Chan, AWH, Chhabra, PS, Sorooshian, A, Pye, HOT, Crounse, JD, Wennberg, PO, Flagan, RC, and Seinfeld, JH (2008) Secondary organic aerosol (SOA) formation from reaction of isoprene with nitrate radicals (NO3) Atmospherics Chemistry and Physics 8: 4117 - 4140.
Pye, HOT, Chan, AWH, Barkley, MP, and Seinfeld, JH (2010) Global modeling of organic aerosol: the importance of reactive nitrogen (NOx and NO3) Atmospheric Chemistry and Physics 10(22): 11261-11276
Wexler, AS, and Seinfeld, JH (1990) The distribution of ammonium salts among a size and composition dispersed aerosol. Atmospheric Environment 24A: 1231 -  1246.
Wexler, AS, and Seinfeld JH (1991) 2nd-generation inorganic aerosol model.  Atmospheric Environment-Part A, 25:2731 -  2748.
Organization: State of Missouri Department of Natural Resources
Comment:
State of Missouri Department of Natural Resources
Missouri recommends that EPA use CAMx for ozone and Community Multi-scale Air Quality (CMAQ) modeling for 24-hour and annual PM2.5 given that previous modeling studies indicated that CMAQ performed better than CAMX in predicting PM2.5 concentrations: Output from CMAQ then can be converted to CAMX format in order to conduct source apportionment analysis. [EPA-HQ-OAR-2009-0491-3806, p.2]
Response:
EPA selected CAMx as the air quality modeling tool for modeling both ozone and PM2.5 because (1) CAMx is a state-of-the-science photochemical model which is designed to simulate the formation, transport, and fate of ozone and PM2.5 and precursor species on regional and national spatial scales, (2) CAMx is instrumented with source apportionment tools which provide a means to quantify interstate contributions of ozone and PM2.5 component species, and (3) CAMx has been widely used by the modeling community for calculating ozone and PM2.5 concentrations and source culpability.  CMAQ is also a widely used state-of-the science photochemical model.  However, an independent peer review of the source apportionment tools in CAMx and CMAQ was more favorable in terms of the design and implementation of the tools in CAMx.  Using a single model for simulating both ozone and PM2.5 ensures physical and chemical consistency in the predictions for these pollutants that would not be possible using two different models.
Organization: Texas Commission on Environmental Quality
Comment:
Texas Commission on Environmental Quality
Modeling for Texas, while challenging, is far from intractable. The TCEQ has conducted many successful modeling demonstrations during the past two decades, most recently the 2010 HGB Attainment Demonstration SIP revision adopted in March of this year. Using refined modeling techniques and up-to-date inventories, the TCEQ has demonstrated satisfactory base-case model performance and predicted credible future design values. The TCEQ's modeling is thoroughly documented, and all modeling input files are available upon request or have already been provided to the EPA for their review during the attainment demonstration review process. The EPA is invited to take advantage of the TCEQ's modeling successes to improve their efforts. [EPA-HQ-OAR-2009-0491-2857.2, p.7]
Response:
EPA appreciates the offer by TCEQ of their modeling input files for use in the Transport Rule.
Organization: Utility Air Regulatory Group (UARG)
Comment:
Utility Air Regulatory Group (UARG)
EPA Should Return to Its "Monitored-Plus-Modeled" Approach
EPA should not have abandoned use of the "monitored-plus-modeled" approach that it used in CAIR and the NOx SIP Call rule to determine downwind nonattainment areas to be addressed. EPA provides no justification in its proposal for its decision to jettison this approach. The monitored-plus-modeled approach is preferable to the approach used in the Proposed Transport Rule because the inclusion of monitored data helps provide a grounding in real-world air quality that is lost in EPA's novel "modeling-only" approach that relies exclusively on IPM projections. It is by no means clear that IPM is even fit to be used in the manner in which EPA used it in developing the Proposed Transport Rule. IPM is a least-cost economic model that operates on a regional scale and is not designed to replicate real-world scenarios in specific locations. See section VIII infra for further discussion of IPM. Furthermore, LADCO specifically recommended that EPA continue to use the "monitored-plus-modeled" approach. LADCO Letter, attachment at 2. Equally important, the use of monitored data for this purpose was never challenged or criticized in North Carolina v. EPA. [EPA-HQ-OAR-2009-0491-2756.1 ,p. 58]
If EPA had considered current monitored data, it would have found that many of the areas that it projects, in the Proposed Transport Rule, to be downwind nonattainment areas in fact currently have air quality that is in attainment of the ozone and/or PM2.5 NAAQS. For example, nearly 60 percent of the monitoring sites that EPA projects to be in nonattainment areas for the 24-hour PM2.5 NAAQS in 2012 in fact are in either currently designated attainment areas or areas that have air quality that is in attainment of that NAAQS, according to an EPA determination after notice-and-comment rulemaking. See Attachment III hereto at Table II for details. Likewise, EPA has determined or proposed to determine that approximately 20 percent of the monitoring sites that EPA projects to be in nonattainment areas for the annual PM2.5 NAAQS and approximately 10 percent of the sites that EPA projects to be in nonattainment areas for the 8-hour ozone NAAQS are in areas that currently have air quality that meets the relevant NAAQS. See id. at Tables I and III respectively for details. Given the prevailing downward trend in ambient concentrations, it is most unlikely that these areas should be viewed as downwind problem areas. [EPA-HQ-OAR-2009-0491-2756.1, pp.58-59] [[See Docket Number EPA-HQ-OAR-2009-0491-2756.1, pp.169-173 for Attachment III.]
EPA should return to its monitored-plus-modeled approach in this rulemaking, or at a minimum, should explain the basis for its departure from that approach, including how its reasoning has changed and why it believes that current monitored air quality data is not relevant to this rulemaking. 34 [EPA-HQ-OAR-2009-0491-2756.1, pp.59-60]
The role of NOx in particulate matter formation is further complicated by recent research demonstrating that the production of biogenic secondary organic aerosol ("SOA") is heavily influenced by NOx levels. Specifically, this research shows that biogenic SOA, particularly isoprene, is enhanced with lower NOx levels due to changes in the fate of peroxy radicals. Air quality models at present do not include this newly discovered chemistry. In addition, the proper simulation of ammonium nitrate and other nitrate aerosol (e.g., organic nitrates) has confounded air quality scientists for many years. Thus, the representation of the impacts of NOx emission changes in particulate matter levels in these models is incomplete, particularly when attempting to simulate relatively small signals such as interstate contributions to ambient particulate matter concentrations. [EPA-HQ-OAR-2009-0491-2756.1, pp.77]
Footnote 34: EPA also must consider the results of air quality modeling and other analyses performed for the Midwest Ozone Group ("MOG") and reported in MOG's comments filed in this docket, dated October 1, 2010. MOG's comments show, among other things, that existing controls, including CAIR, are projected to resolve most of the downwind PM2.5 and ozone air quality problems in at least a large section of the PTR domain by no later than 2014. Moreover, MOG's comments demonstrate that, much as is shown in UARG's comments, there are substantially fewer existing nonattainment problems in the PTR domain than EPA's proposal suggests.
Response:
See preamble section V.C.2.
The comments related to the current understanding of the impact of NOx on biogenic SOA and the simulation of ammonium nitrate do not reflect the state-of-the-science and noticeably lack supporting references.  While earlier studies (e.g., Kroll et al., 2006) reported increases in SOA associated with decreases in NOx from the isoprene-plus-OH pathway, recent work (e.g., Chan et al., 2010) suggests that SOA production from isoprene oxidation by OH can be similar for high- and low-NOx conditions at atmospherically relevant NO2-to-NO  ratios.  Additionally, a recent study (Ng et al., 2008) suggests that increases in biogenic SOA could be associated with increases in NOx via the isoprene-plus-NO3 radical pathway.  Furthermore, Ng et al. (2007) have reported increases in biogenic SOA associated with increases in NOx for the sesquiterpene-plus-OH pathway.  Therefore, even if a "dis-benefit" in biogenic SOA formation via the isoprene-plus-OH pathway occurred under reduced-NOx conditions, it could be compensated for by a potential "benefit" in biogenic SOA reduction via other pathways (e.g., sesquiterpenes-plus-OH, isoprene-plus-nitrate radical).  Indeed, a preliminary global modeling study that accounts for benefit and disbenefit pathways suggests that their impacts may largely cancel in the Southeast US (Pye et al., 2010).  While the dependence of biogenic SOA formation on NOx levels is an area of ongoing research, the current literature does not implicate a significant dis-benefit of biogenic SOA formation in the Southeast US associated with reductions in NOx concentration.
EPA disagrees with the comment that the simulation of ammonium nitrate aerosol confounds air quality scientists.  The thermodynamic and dynamic processes governing ammonium nitrate aerosol formation have been understood for many years (e.g., Bassett and Seinfeld, 1983; Wexler and Seinfeld, 1990, 1991).  The early challenge to representing ammonium nitrate formation in 3D photochemical models was related to the computationally intensive nature of the calculations rather than unknown chemical and physical processes.  However, thermodynamic modules were developed in the 1990s to efficiently solve the inorganic thermodynamic aerosol problem (e.g., ISORROPIA; Nenes et al., 1998).  Current state-of-the-science photochemical models, including CAMx, include such thermodynamic modules.
 References:
Bassett, ME, and Seinfeld, JH (1983) Atmospheric equilibrium model of sulphate and nitrate aerosols, Atmospheric Environment 17:2237 - 2252.
Chan, AWH, Chan, MN, Surratt, JD, Chhabra, PS, Loza, CL, Crounse, JD, Yee, LD, Flagan, RC, Wennberg, PO, and Seinfeld, JH (2010) Role of aldehyde chemistry and NOx concentrations in secondary organic aerosol formation. Atmospheric Chemistry and Physics 10(15): 7169-7188.
Foley, KM, Roselle, SJ, Appel, KW, Bhave, PV, Pleim, JE, Otte, TL, Mathur, R, Sarwar, G, Young, JO, Gilliam, RC, Nolte, CG, Kelly, JT, Gilliland, AB, and Bash, JO (2010) Incremental testing of the Community Multiscale Air Quality (CMAQ) modeling system version 4.7. Geoscientific Model Development 3:205 - 226.
Kroll, JH, Ng, NL, Murphy, SM, Flagan, RC, and Seinfeld, JH (2006) Secondary organic aerosol formation from isoprene photooxidation. Environmental Science & Technology 40(6): 1869-1877.
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Organization: we energies
Comment:
we energies
We would also like to comment on the availability of additional modeling conducted by Alpine Geophysics and analyses by Environ Corp. that was recently presented to the Lake Michigan Air Directors Consortium (LADCO). This modeling is based on updated baseline data and more recent ozone and PM2.5 design values. Importantly, the results of this modeling reach the conclusion that both the ozone and PM2.5 objectives of the proposed rule can be achieved by 2014 with no new controls (with the possible exception of local controls at two locations). [EPA-HQ-OAR-2009-0491-2629.1, p.2]
Response:
See preamble section V.C.2.

IV.C.2. How Did EPA Project Future Nonattainment and Maintenance for Annual PM2.5, 24-Hour PM2.5, and 8-Hour Ozone?

Organization: George Washington University Regulatory Study Center
Comment:
George Washington University Regulatory Study Center
The preamble only reports a select comparison of Comprehensive Air Quality Model with Extensions (CAMx) model predictions with actual measured concentrations of PM in 2005: [EPA-HQ-OAR-2009-0491-2573.1, p.22]
"The two PM2.5 species that are most relevant for this proposal are sulfate and nitrate. For the summer months of June through August, when observed sulfate concentrations are highest in the East, the model predictions of 24-hour average sulfate were lower than the corresponding measured values by 7 percent at urban sites and by 9 to 10 percent at rural sites in the IMPROVE and CASTNET monitoring networks, respectively. For the winter months of December through February, when observed nitrate concentrations are highest in the East, the model predictions of 24-hour average particulate nitrate were lower than the corresponding measured values by 12 percent at urban sites and by 4 percent at rural sites in the IMPROVE monitoring network." [EPA-HQ-OAR-2009-0491-2573.1, p.22]
But this kind of comparison only tells a part of the story and is of limited value in understanding the uncertainty in the CAMx modeling results. The comparisons reported in the preamble -- measures of "bias" in the predicted concentrations -- indicate that across the predicted-observed pairs in the sample the overestimates are roughly balanced by the underestimates. This could be a comforting statistic if one is using the results to provide some average estimate across all the sites in the sample. However, the issue is with the variability in the model estimates at specific sites -- the non-attainment areas in the eastern U.S. Appendix A provides a second set of "error" measures -- the normalized mean error and the mean fractional error -- that suggest there is a substantial variation in estimates around the observed levels.46 (See Error! Reference source not found.) For summertime sulfate levels, these error measures range from 40 to 50 percent. And, for wintertime nitrate levels, these errors range from 50 to 100 percent. While these measures suggest significant variation in projected versus observed concentrations, they do not provide adequate information on the underlying distributions. EPA should use the underlying data used to generate these measures of model performance in developing an analysis of the variation for its projections of contribution and interference for downwind nonattainment areas. [EPA-HQ-OAR-2009-0491-2573.1, pp.22-23]

 46 These measures are based on the sum of the absolute value of the error between projected levels and observed levels. The general practice is to represent the variability in a distribution by calculating the variance of a distribution which would be based, in this case, on the sum of squares of the errors in projected and observed levels. The variance places a greater weight on large errors than is the case for the error measures reported in Appendix A.
Response:
EPA has completed an expanded model performance evaluation using the predictions from the updated 2005 base year CAMx simulation conducted for the final Transport Rule.   This evaluation provides additional spatial and temporal performance results in response to comments.  The model performance results can be found in Appendix A of the Final Transport Rule Air Quality Modeling Technical Support Document.
Organization: Kansas City Board of Public Utilities (BPU)
Independence Power & Light (IPL)
Comment:
Independence Power & Light (IPL)
EPA PLACES GREATER RELIANCE ON THE CAMx MODELING FOR DOWNWIND EMISSIONS THAN CAN BE JUSTIFIED EPA PLACES GREATER RELIANCE ON THE CAMx MODELING FOR DOWNWIND EMISSIONS THAN CAN BE JUSTIFIED
Although the level of detail suggests a very high degree of precision, closer analysis reveals that the modeling cannot bear the evidentiary weight assigned it. In particular, as shown on the attached letter from Mr. Hoffnagle of TRC, the modeling cannot ascribe upwind contributions to downwind states at an acceptable degree of accuracy beyond 200 kilometers and the error ranges surrounding the predicted results are high and vary from positive to negative in differing seasons, thus suggesting a high degree of variance in the estimated results. Given these issues, attempting to pinpoint based on this modeling the emissions reductions purportedly necessary at individual EGUs, as Appendix A does, simply is more than can be justified. [EPA-HQ-OAR-2009-0491-2741.1, pp.8-9]
EPA previously found that long range transport models, albeit not including CAMx, do not reproduce measured data beyond 200 kilometers. See Hoffnagle letter, citing interagency Workgroup on Air Quality Models (EPA-454/R-98-019). The Rule does not identify, much less refute, this concern despite the fact that many of the downwind nonattainment and maintenance sites are located significantly more than 200 kilometers of the upwind EGU. For example, the closest downwind 24-hour PM25 nonattainment sites of the 17 Missouri sites (75 FR at 45257, Table IV.C-14) to IPL's Blue Valley Power Plant is St. Clair County, n, which is 386 kilometers from IPL's EGU. As this is nearly double the distance at which long range transport models lose accuracy (and, of course, the other 16 listed downwind sites for Missouri, id., are even farther away), it is highly questionable that the model has accurately predicted the Blue Valley plant's actual contribution in St. Clair or the other sites. [EPA-HQ-OAR-2009-0491-2741.1, pp.9-10]
This conclusion is further supported by the facts that the model does not measure PM2.5 at the downwind monitoring sites, but measures individual species of particulate at the upwind sources. Hoffnagle letter at ¶ 3; see 45 FR at 45253/1 ('CAMx employs enhanced source apportionment techniques which track the formation and transport of ozone and particulate matter from specific emission sources and calculates the contribution of sources and precursors to ozone and PM2 5 for individual receptor locations'). As a result, no error rates are available for PM2.5 projections at the sites, but only for sulfates and nitrates at the upwind sources. Jd. The sulfate and nitrate error rates shows the models under- and over-predict at different times of the year, which means a relatively wide confidence interval related to any prediction. Jd. Similar error rate problems are present for the ozone modeling. Hoffnagle letter at ¶ 20. [EPA-HQ-OAR-2009-0491-2741.1, p.10]
The practical effect of these error rates has been recognized in the SIP process where predicted results are calibrated to measured results for the purpose of eliminating model variance when applied to a specific area. Hoffnagle letter at ¶ 4. No such calibration was undertaken in connection with the predicted results used in development of the predicted upwind contributions at numerous downwind sites. Id. This omission opens the possibility that the predictions vary substantially from what actual measured emissions would be at any specific site. The Rule does not address this possibility, despite the fact eliminating such variances could dramatically affect the predicted estimates of upwind contributions. [EPA-HQ-OAR-2009-0491-2741.1, pp.10-11]
The need for calibration in light of the wide confidence intervals is heightened because the purported contributing emissions from any single source as tiny numbers. For example, Mr. Hoffnagle estimates that IPL's Blue Valley unit will represent 0.0075% of 2012 Missouri S02 emissions and 0.00092% of 2012 Missouri NOx emissions. Id. at ¶ 6. Absent some precise calibration that was not done, it seems highly likely the Blue Valley emissions are 'lost in the noise' surrounding the total Missouri level. Further, as the upwind 'contributions to downwind nonattainment and maintenance receptors for the Transport Rule were calculated using a relative approach,' 75 FR at 45254, it is evident that IPL's Blue Valley emissions will have a nearly imperceptible effect on the downwind sites. For example, Mr. Hoftnagle calculates that effect of completely eliminating IPL's Blue Valley NOx emissions would produce a 0.00093 ppb reduction in St. Clair, II's maximum ozone concentration, assuming Missouri were entirely responsible for all St. Clair's ozone concentration. Hoffnagle letter at ¶ 7. Similar results apply for PM2.5 concentrations and would also apply to other sites. Id. [EPA-HQ-OAR-2009-0491-2741.1, p.11]
These numbers on their own are well below what can be accurately measured, let alone what can be accurately estimated. And that is not even considering the high error rate and the long range inaccuracy of the modeling used in the Rule. The degree of precision that EPA proposes for the Rule and Appendix A in setting 2012 allowances for individual EGUs is unwarranted. This, in tum, means that the conclusions reached are not supported by the facts on which EPA relied, which indicates arbitrary and capricious decision-making. [EPA-HQ-OAR-2009-0491-2741.1, p.11]
Kansas City Board of Public Utilities (BPU)
EPA PLACES GREATER RELIANCE ON THE CAMx MODELING FOR DOWNWIND EMISSIONS THAN CAN BE JUSTIFIED EPA PLACES GREATER RELIANCE ON THE CAMx MODELING FORDOWNWIND EMISSIONS THAN CAN BE JUSTIFIED
Although the level of detail suggests a very high degree of precision, closer analysis reveals that the modeling cannot bear the evidentiary weight assigned it. In particular, as shown on the attached letter from Mr. Hoffnagle of TRC, the modeling cannot ascribe upwind contributions to downwind states at an acceptable degree of accuracy beyond 200 kilometers and the error ranges surrounding the predicted results are high and vary from positive to negative in differing seasons, thus suggesting a high degree of variance in the estimated results. Given these issues, attempting to pinpoint based on this modeling the emissions reductions purportedly necessary at individual EGUs, as Appendix A does, simply is more than can be justified. [EPA-HQ-OAR-2009-0491-2740.1, p.15]
EPA previously found that long range transport models, albeit not including CAMx, do not reproduce measured data beyond 200 kilometers. See Hoffnagle letter at  ¶ I, citing interagency Workgroup on Air Quality Models (EPA-454/R-98-019). The Rule does not identify, much less refute, this concern despite the fact that many of the downwind nonattainment and maintenance sites are located more than 200 kilometers of the upwind EGU. For example, the closest downwind 24-hour PM25 maintenance site of the two Kansas linked sites (75 FR at 45266, Table IV.C-18) or the single linked 8-hour ozone maintenance site to BPU's electric generating units is Muscatine IA, which is 400 kilometers away. As this is virtually double the distance at which long range transport models lose accuracy (and, of course, the other 2 sites for Kansas - Dallas TX and Milwaukee, WI - id., are even farther away), it is highly questionable that the model has accurately predicted the BPU units' actual contribution in Muscatine or the other two sites. [EPA-HQ-OAR-2009-0491-2740.1, p.15]
This conclusion is further supported by the facts that the model does not measure PM25 at the downwind monitoring sites, but measures individual species of particulate at the upwind sources. Hoffnagle letter at  ¶ 3; see 45 FR at 45253/1 ('CAMx employs enhanced source apportionment techniques which track the formation and transport of ozone and particulate matter from specific emission sources and calculates the contribution of sources and precursors to ozone and PM,s for individual receptor locations'). As a result, no error rates are available for PM25 projections at the sites, but only for sulfates and nitrates at the sources. Hoffnagle letter at  ¶ 3. The sulfate and nitrate error rates show the models under- and over-predict at different times of the year, which means a relatively wide confidence interval related to any prediction. Id. Similar error rate problems are present for the ozone modeling. Hoffnagle letter at ~ 2.  [EPA-HQ-OAR-2009-0491-2740.1, pp.15-16]
The practical effect of these error rates has been recognized in the SIP process where predicted results are calibrated to measured results for the purpose of eliminating model variance when applied to a specific area. Hoffnagle letter at  ¶ 4. No such calibration was undertaken in connection with the predicted results used in development of the predicted upwind contributions at numerous downwind sites. Id. This omission opens the possibility that the predictions vary substantially from what actual measured emissions would be at any specific site. The Rule does not address this possibility, despite the fact eliminating such variances could dramatically affect the predicted estimates of upwind contributions.  [EPA-HQ-OAR-2009-0491-2740.1, p.16]
The need for calibration in light of the wide confidence intervals is heightened because the purported contributing emissions from BPU is a relatively small fraction of the total Kansas number. For example, Mr. Hofnagle estimates that BPU's units will represent 9.5% of 2012 Kansas S02 emissions and 1.9% of 2012 Kansas NOx emissions. Id. at  ¶ 6. Mr. Hoffnagle calculates that BPU's units are responsible for 0.04 ppb reduction in Dallas' maximum ozone concentration, which is insufficient to have a serious effect on compliance there. Hoffnagle letter at  ¶ 7. BPU's portion of the Kansas total for PM2 5 concentrations at Milwaukee is even smaller, and thus would have a much lesser effect there. Id. at  ¶ 8.  [EPA-HQ-OAR-2009-0491-2740.1, p.16]
These numbers also must be considered in light of the high error rate and the long range inaccuracy of the modeling used in the Rule. When those considerations are factored into the analysis, they raise serious concerns about the degree of precision that EPA proposes for the Rule and Appendix A in setting 2012 allowances for individual EGUs. Failure to address those considerations is evidence of arbitrary and capricious decisionmaking. [EPA-HQ-OAR-2009-0491-2740.1, p.17]
Response:
EPA disagrees with this comment.  The commenter describes distance limitations and accuracy of non-steady-state puff dispersion models from long-range transport from large point sources to distant Class I areas.  Such models are designed primarily for use in modeling the impacts of inert pollutants in support of analyses relevant to Prevention of Significant Deterioration (PSD) (See 40 CFR Part 51 Appendix W).   The commenter incorrectly assumes that the limitations and accuracy of non-steady-state long-range transport models are also applicable and relevant to photochemical grid models, like CAMx.   CAMx is specifically designed for simulation of ozone, PM2.5 and other pollutants over many spatial scales ranging from sub-urban to continental (Environ, 2010).  EPA has identified CAMx as one of several candidate models that are applicable for use by states in attainment demonstration modeling for ozone, PM2.5 and regional haze State Implemetation Plans.  EPA has successfully used grid-based photochemical models for applications on regional and national scales in support of numerous rulemakings (Light Duty Greenhouse Gas Rule: EPA-HQ-OAR-2009-0472; Heavy Duty Greenhouse Gas Rule: EPA-HQ-OAR-2010-0162; Reformulated Fuels-II: EPA-HQ-OAR-2005-0161; C-3 Commercial Marine Engine Rule:  EPA-HQ-OAR-2007-0121; and Locomotive/Marine Engine Rule: EPA-HQ-OAR-2003-0190).
EPA provides model performance results for sulfate and nitrate as well as other components of PM2.5 in Appendix A of the Air Quality Modeling Technical Support Document.
Contrary to the assertion by the commenter, EPA does use measured data to provide the foundation for projection of PM2.5 concentrations.  The procedures used by EPA for coupling model predictions with measured data for use in projecting PM2.5 concentrations for the Transport Rule are described in the Air Quality Modeling Technical Support Document.  These procedures are consistent with recommendations in EPA's modeling guidance for ozone and PM2.5  attainment demonstrations (EPA-HQ-2009-0491-4361).
In interpreting the purported contributions from the individual sources cited, the commenter fails to recognize the importance of these contributions as part of the "collective contribution" that comprises transported ozone and PM2.5 (see preamble section V.D.1).  The commenter also fails to acknowledge that the relative contributions from individual sources on cumulative impacts depends on several factors in addition to emissions such as distance, meteorology, and chemical transformation.
Organization: Kentucky Division for Air Quality
Comment:
Kentucky Division for Air Quality
More Recent Ambient Air Quality Data Should Have Been Utilized in EPA's Modeling
Pursuant to the proposed Transport Rule IV.C.2., How did EPA project future nonattainment and maintenance for the 1997 and 2006 air quality standards (75 FR 45246), EPA's approach for projecting future ozone and PM2.5 design values involved the use of 2003-2007 ambient air quality data. The Division finds that this approach to be somewhat lacking when more recent data for 2007-2009 was available. The use of more recent air quality data in EPA's modeling analysis for the proposed Transport Rule may have provided different final modeling results by more realistically capturing some of the air quality benefits and improvements provided by CAIR which began on January1, 2009. [EPA-HQ-OAR-0491-2805.1, p.6]
Response:
See preamble section V.C.2.
Organization: New York State Department of Environmental Conservation
Comment:
New York State Department of Environmental Conservation
Other factors are unknown as to how this analysis was conducted, such as whether alternate selection criteria for the RRF calculation (e.g., top 5 percent of modeled days in each quarter) were considered and if not, why not, what was the impact of alternative criteria, and why was the 10 percent criterion selected. For calculating quarterly ambient PM2.5 concentrations and species fractions, it is unclear if criteria other than the 'top 10 percent days' were considered and what the impact was of alternative criteria, These aspects of the analysis should be clarified. When calculating 8-hr ozone interstate contributions for the 2012 base case, no RRF and no interstate contributions were calculated at monitors where there are fewer than five days with modeled daily max 8-hr ozone concentrations less than 70 ppb in the 2012 base case simulations. However, EPA should clarify if there are any monitors where this criterion meant that no interstate contributions could be calculated and where they might be located, and what their 2012 base case design value / maximum design values were. [EPA-HQ-OAR-2009-0491-2730.1, p.11]
Response:
EPA calculated the "high" ambient days and "high" modeled days based on the top 10% of measured or modeled days in each quarter.  While we could have used an alternative definition of high days, we believe the choice of 10% is reasonable and appropriate for the reasons explained below.
Ambient PM2.5 FRM monitoring sites collect filter based samples on either a daily basis or once every 3 or 6 days.  For these sites, the top 10% of days varies between 1 and 9 days per quarter (depending of the sampling frequency).  The majority of sites operate on a 1 in 3 day schedule.  The top 10% of days at these sites (if data is complete for every schedule sampling day) is 3 days per quarter.  The CAMx model output contains data for every day of the year.  Therefore, from the model output, the top 10% of days per quarter is always 9 days.
In the attainment test, we want to average a number of days together, so that the species fractions and/or relative response factors are relatively robust.  The goal is to represent the average conditions on high days.  At the same time, we do not want to average together too many days because the average of a large number of days will not adequately represent the "high" days or the 98[th] percentile.  Therefore we believe the choice of 10% (which in most cases is 3 to 9 days per quarter) is a good compromise between averaging too many days and too few days.  As such, use of the top 10% of days per quarter is the default recommendation in the updated 24-hour PM2.5 attainment test guidance. Therefore, EPA is using the top 10% of days per quarter in all of our future year 24-hr PM2.5 design value calculations and we have made the top 10% of ambient and modeled days the default setting in the MATS attainment test software.
In response to the comment related to the minimum number of days in the ozone attainment test and contribution test:  In the final rule modeling, there are at least 5 modeled days above 70 ppb at every ozone monitor with a base year 2003-2007 five year weighted average concentration of 80 ppb or greater.  Therefore, there is a projected 2012 design value for every monitor that has the potential to have a design value greater than or equal to 85 ppb in the future (2012).  On the contribution calculation side, in the final rule modeling there are 16 monitors which are projected as ozone nonattainment and/or maintenance sites in 2012.  Of those, contributions were not calculated at 6 sites because there were fewer than 5 modeled days above 70 ppb in 2012 at those sites.  All 6 of those monitoring sites are in Harris County Texas.  Of note, there are an additional 2 nonattainment and 2 maintenance sites in Harris County where contributions were calculated.
Organization: Tampa Electric Company
Comment:
Tampa Electric Company
[These comments were submitted as testimony at the Philadelphia, Pennsylvania public hearing on August 26, 2010.  See Docket Number EPA-HQ-OAR-0491-1938, p.71.]
We also find it curious the model finds that emissions generated in Florida have downwind effects in Georgia and Texas for ozone non-attainment, but does not have an effect on Louisiana or Alabama. This seems to be evidence of the need to use human judgment in interpreting the model. Don't just assume the output is wholly infallible.
Response:
Based on the air quality modeling for the Final Transport Rule, Florida contributes to 8-hour ozone in amounts at or above the 0.8 ppb threshold to a total of 26 monitoring sites in 6 other States (i.e., Alabama, Georgia, Louisiana, Mississippi, South Carolina, and Texas).  However, only 2 of these sites, both in Harris county, Texas are projected to be nonattainment and/or have maintenance problems for the 1997 8-hour ozone NAAQS for 2012 base case and are, therefore, relevant receptors for the Transport Rule.
Organization: Westar Energy, Inc.
Comment:
Westar Energy, Inc.
EPA PLACES GREATER RELIANCE ON THE CAMX MODELING FOR DOWNWIND EMISSIONS THAN CAN BE JUSTIFIED [EPA-HQ-OAR-2009-0491-2757.1, p.14]
To determine the impact of upwind emissions on downwind nonattainment and maintenance locations, EPA employed the 'CAMx photochemical apportionment modeling to quantify the impact of emissions in specific upwind states on projected downwind nonattainment and maintenance receptors for both PM2.5 and 8-hour ozone.' 75 FR at 4525311. The Rule states that this approach is 'particularly well-suited for quantifying interstate contributions' because it 'explicitly tracks the formation and transport of all ozone and PM 2.5 mass.' Id. at 45253/2. [EPA-HQ-OAR-2009-0491-2757.1, p.14]
For contribution modeling, EPA employed similar tagging approaches to track PM 2.5 and ozone source category, species, and precursor emissions. 75 FR at 4525411-2. EPA then determined 'those monitoring sites which are projected to exceed the NAAQS in the 2012 base case, and calculated that contribution to nonattainment and maintenance separately at those sites using the single largest contribution for each upwind State in 2012. Id at 45254-55 & Table IV.C-13. This modeling resulted in a list of downwind nonattainment and maintenance sites linked to upwind States. See 75 FR at 45258-67 (tables for PM2.5) and 45267-70 (tables for ozone). [EPA-HQ-OAR-2009-0491-2757.1, pp.14-15]
Although the level of detail suggests a very high degree of precision, closer analysis reveals that the modeling cannot bear the evidentiary weight assigned it. In particular, as shown on the attached letter from Mr. Glen Hoffnagle of TRC, the modeling cannot ascribe upwind contributions to downwind states at an acceptable degree of accuracy beyond 200 kilometers. The error ranges surrounding the predicted results are high and vary from positive to negative in differing seasons, thus suggesting a high degree of variance in the estimated results. Given these issues, attempting to pinpoint the emissions reductions purportedly necessary at individual EGUs, as Appendix A does, simply is more than can be justified. [EPA-HQ-OAR-2009-0491-2757.1, p.15]
EPA itself previously found that long range transport models, albeit not including CAMx, do not reproduce measured data beyond 200 kilometers. See Interagency Workgroup on Air Quality Models (EPA-454/R-98-019). The Rule does not identify, much less refute, this concern despite the fact that many of the downwind nonattainment and maintenance sites are located significantly more than 200 kilometers from the upwind EGD. For example, the closest downwind 24-hour PM2.5 maintenance site of the two Kansas linked sites (75 FR at 45266, Table IV.C-18) or the single linked 8-hour ozone maintenance site to Westar's electric generating units is Muscatine IA, which is 473 kilometers away. As this is more than double the distance at which long range transport models lose accuracy (and, of course, Dallas and Milwaukee, the other two Kansas downwind sites, id., are more than 700 kilometers from Westar's units), it is highly questionable that the model has accurately predicted Westar's actual contribution to those three sites. [EPA-HQ-OAR-2009-0491-2757.1, pp.15-16]
This conclusion is further supported by the facts that the model does not predict PM2.5 at the downwind monitoring sites, but predicts individual species of particulate at the upwind sources. Hoffnagle letter; see 45 FR at 45253/1 ('CAMx employs enhanced source apportionment techniques which track the formation and transport of ozone and particulate matter from specific emission sources and calculates the contribution of sources and precursors to ozone and PM2.5 for individual receptor locations'). As a result, no error rates are available for PM2.5 projections at the sites, but only for sulfates and nitrates at the sources. Id. The sulfate and nitrate error rates shows the models under- and over-predict at different times of the year, which means a relatively wide confidence interval related to any prediction. Id. Similar error rate problems are present for the ozone modeling. Hoffnagle letter. [EPA-HQ-OAR-2009-0491-2757.1, p.16]
The practical effect of these error rates has been recognized in the SIP process where predicted results are calibrated to measured results for the purpose of eliminating model variance when applied to a specific area. Hoffnagle letter. No such calibration was undertaken in connection with the predicted results used in development of the predicted upwind contributions at numerous downwind sites. Id. This omission opens the possibility that the predictions vary substantially from what actual measured emissions would be at any specific site. The Rule does not address this possibility, despite the fact that eliminating such variances could dramatically affect the predicted estimates of upwind contributions. [EPA-HQ-OAR-2009-0491-2757.1, p.16]
The import of these types of problems is reflected in the attached Trinity Report at p. 5-1 [See p.28 of this comment summary for the Trinity Report], which concludes that the proposed emissions reductions at Westar's units will have a very small impact on the linked downwind sites. For the Dallas downwind site, the effect of the 2012 NOx and S02 emission reductions from the Jeffrey Energy Center Units is estimated to be 0.043 ppb, or less than 0.05% of the original design value. This result occurs because other factors, specifically that the monitor is VOC-limited, affect whether the ozone concentration at the Dallas monitor is responsive to NOx emission changes. Id. Consequently, it is an open question how effective a NOx control at Westar's Jeffrey Units will be in alleviating ozone formation at the Dallas monitor. [EPA-HQ-OAR-2009-0491-2757.1, pp.16-17]
A similar disconnect between expectation and reality occurs with regard to the effects of NOx and S02 reductions at the Jeffrey Units. As adjusted by Trinity, the NOx and S02 reductions at the Jeffrey Units will account for approximately 13% and 4% reductions of each pollutant. But the effect of those reductions on the Milwaukee and Muscatine downwind sites linked to Kansas are much less impressive. The Milwaukee monitor would experience only a 0.04% proportionate reduction, while Muscatine's proportionate reduction of 0.3%. Trinity Report at 5-1. Again, the very low proportionate reduction at Milwaukee appears to be due to factors other than Jeffrey Units reduced emission. Specifically, because of the Milwaukee monitor's proximity to Lake Michigan, it, like other monitors near large bodies of water, has a low response to the NOx and the S02 reductions due to ambient conditions in those areas and the non-linear relationship between the formation of certain PM25 species and precursor emissions. Id. The point in all this comes down to the fact that these proceedings involve complicated matters that change under actual real world scenarios but the effects of those changes have not been factored into the current modeling. Thus, that modeling has only limited usefulness in determining what downwind reductions will result from what projected emissions restrictions at upwind sources, and does not provide the type of certainty that is suggested by the very specific EGU allowances set forth in Appendix A of the Rule.  [EPA-HQ-OAR-2009-0491-2757.1, p.17]
Response:
EPA disagrees with this comment.  The commenter describes distance limitations and accuracy of gaussian long-range transport models that are designed primarily for use in modeling inert pollutants in support of analyses relevant to Prevention of Significant Deterioration (PSD) (See 40 CFR Part 51 Appendix W).   The commenter incorrectly assumes that the limitations and accuracy of gaussian long-range transport models are also applicable and relevant to photochemical grid models, like CAMx.   CAMx is specifically designed for simulation ozone, PM2.5 and other pollutants over many spatial scales ranging from sub-urban to continental (Environ, 2010).  EPA has identified CAMx as one of several candidate models that are applicable for use by states in attainment demonstration modeling for ozone, PM2.5 and regional haze State Implementation Plans.  EPA has successfully used grid-based photochemical models for applications on regional and national scales in support of numerous rulemakings (Light Duty Greenhouse Gas Rule: EPA-HQ-OAR-2009-0472; Heavy Duty Greenhouse Gas Rule: EPA-HQ-OAR-2010-0162; Reformulated Fuels-II: EPA-HQ-OAR-2005-0161; C-3 Commercial Marine Engine Rule:  EPA-HQ-OAR-2007-0121; and Locomotive/Marine Engine Rule: EPA-HQ-OAR-2003-0190).
EPA provides model performance results for sulfate and nitrate as well as other component of PM2.5 in Appendix A of the Air Quality Modeling Technical Support Document.
Contrary to the assertion by the commenter, EPA does use measured data to provide the foundation for projection of PM2.5 concentrations.  The procedures used by EPA for coupling model predictions with measured data for use in projecting PM2.5 concentrations for the Transport Rule are described in the Air Quality Modeling Technical Support Document.  These procedures are consistent with recommendations in EPA's modeling guidance for ozone and PM2.5 attainment demonstrations ( EPA-HQ-2009-0491-4361).
In interpreting the purported contributions from the individual sources cited, the commenter fails to recognize the importance of these contributions as part of the "collective contribution" that comprises transported ozone and PM2.5 (see preamble section V.D.1)
The commenter provided no data to support the contention that monitoring locations near large bodies of water have a low response to emissions.
The EGU allowances are not based on the air quality contributions from individual units (see preamble section VII for procedures used by EPA for emissions allocations).
IV.C.3. How Did EPA Assess Interstate Contributions to Nonattainment and Maintenance?

Organization: Calpine Corporation
Comment:
Calpine Corporation
We agree with the methodology whereby EPA modeled emissions of fine particulate matter (PM2.5) and ozone precursors in order to determine which upwind areas contributed significantly to downwind state's nonattainment problems. [EPA-HQ-OAR-2009-0491-3614,p .2]
Response:
We appreciate the commenter's support.
Organization: Entergy Services, Inc.
Louisiana Chemical Association (LCA)
Comment:
Entergy Services, Inc.
The EPA Projection that Louisiana Emissions Sources Will Interfere With Maintenance in Harris County, Texas, Is Flawed.  EPA Has Projected Significant Reductions of SO2 and NOx Even Without the Transport Rule and FIP
Entergy adopts comment E.1 made by the Louisiana Chemical Association. In addition to the comments above, Entergy believes that EPA's projection that Louisiana emissions will interfere with maintenance of the annual PM2.5 NAAQS at the Clinton Drive monitor without further controls is flawed.   EPA modeling shows that virtually the entire impact on PM2.5 annual levels at the Clinton Drive monitor are due to sulfate emissions.  The following data, taken from EPA Preamble Tables IV.C-1, IV.C-3 and IV.C-5, and based on the IPM v.3.02 modeling, demonstrate that SO2 emissions from Louisiana will significantly decline, without enactment of the Transport Rule or a FIP: [EPA-HQ-OAR-2009-0491-2847.1,p.10] [[See Docket Number EPA-HQ-OAR-2009-0491-2847.1, p.10 for a table with the data.]]
Louisiana Chemical Association (LCA)
The EPA Projection that Louisiana Emissions Sources Will Interfere With Maintenance in Harris County, Texas, Is Flawed. EPA Has Projected Significant Reductions of SO2 and NOx Even Without the Transport Rule and FIP. [EPA-HQ-OAR-2009-0491-3527.1, p. 10]
In addition to the comments above, LCA believes that EPA's projection that Louisiana emissions will interfere with maintenance of the annual PM2.5 NAAQS at the Clinton Drive monitor without further controls is flawed because EPA overestimated Louisiana emissions in the emissions inventory, failed to account for reductions that will occur due to federal and state enforceable measures, and due to potential modeling errors. Each of these flaws is discussed in more detail below. However, even without correction of those errors, it is readily apparent that even using the flawed projections, it is not reasonable for EPA to conclude that Louisiana emissions will interfere with maintenance in Harris County. [EPA-HQ-OAR-2009-0491-3527.1, p. 10]
Response:
EPA has conducted revised air quality modeling with updates based on comments on the modeling platform used for the proposed rule.  In the revised modeling there are no monitoring sites in Texas with projected 2012 base case nonattainment or maintenance problems for the annual PM2.5 NAAQS.   In addition, Louisiana is not identified in the final rule as a state with emissions that significantly contribute or interfere with maintenance of the 1997 or 2006 PM2.5 NAAQS.
Organization: Maryland Department of Environment (MDE)
Comment:
Maryland Department of Environment (MDE)
The results of the significant contribution analysis are consistent with MDE scientific research. While all air quality model results are a source of considerable uncertainty, the linkages between upwind and downwind states identified in the CAMx source apportionment modeling verify that pollution transport occurs. Research by the University of Maryland - Baltimore County, Howard University, and University of Maryland - College Park has shown differences between long-range transport of ozone and long-range transport of fine particles. High ozone episodes in Maryland are most often accompanied by a westerly wind component and or the late night/early morning occurrence of the nocturnal low level jet (NLLJ). The westerly wind transports ozone, PM2.5 and precursors from the Midwest into Maryland. The NLLJ transports ozone and pollutant precursors from the south into Maryland. In general high fine particulate concentrations are most often accompanied by southwesterly flow. For further information on Maryland research regarding transport of ozone, please see Appendix A: Ozone Reservoir [See EPA-HQ-OAR-2009-0491-2639.2, p.22 for comments pertaining to Appendix A] . [EPA-HQ-OAR-2009-0491-2639.2, p.6]
EPA's Transport Rule analysis is consistent with these Maryland findings. The 24-hour PM2.5 nonattainment and maintenances sites located in Baltimore and Glen Burnie are linked to New Jersey, New York, Ohio, Pennsylvania, and West Virginia, as well as to southern states such as Virginia, North Carolina and Georgia (See Table IV.C-17, on preamble pages 75 FR 45262-45265, September 14, 2010). [EPA-HQ-OAR-2009-0491-2639.2, p.6]
The significant contribution analysis is strengthened by the use of relative response factors and monitor observations. The two federally-approved photochemical models, CMAQ and CAMx, have shown serious discrepancies when each models the same event. However, these models are more consistent when "relative" model results are evaluated instead of absolute results [Hogrefe, et al., Rethinking the assessment of photochemical modeling systems in air quality planning applications, J. Air & Waste Manage. Assoc., 58, 1086 - 1099 (2008)]. The EPA has addressed an important source of model uncertainty by using Relative Response Factors for both identifying nonattainment and maintenance sites and the source apportionment process. The use of real monitor data in these calculations adds an important "reality check" on the contribution amounts. In addition, the use of five years of monitor data instead of one year ensures that naturally variable annual meteorology does not bias the outcome. [EPA-HQ-OAR-2009-0491-2639.2, pp.6-7]
Response:
EPA agrees that pollutants from certain upwind states contribute to air quality in other downwind states/  EPA has conducted revised air quality modeling with updates based on comments on the modeling platform used for the proposed rule.
Organization: Minnesota Power
Comment:
Minnesota Power
Remodel state contributions to nonattainment before rule finalization.  EPA should repeat their air quality modeling analysis, giving consideration to the most recent air quality data (2007 to 2009) and post 2005 emissions control reductions to confirm that the air quality nonattainment areas identified by EPA as significantly impacted by Minnesota and other evaluated state emissions will still be in nonattainment  in the 2012 to 2014 time frame.  Considering analysis performed on Proposed Transport Rule state nonattainment area impacts by Alpine Geophysics and Environ for the Midwest Ozone Group and submitted as comments to this Docket, there is good cause to expect that the annual and 24 hour average PM2.5 standards nonattainment areas cited by EPA as a basis for Minnesota inclusion in the Transport Rule will have reestablished attainment with the NAAQS around the timing EPA is proposing imposition of the 2012 state SO2 and NOx emissions budgets.  [EPA-HQ-OAR-2009-0491-2750.1, p.5]
Transport Rule modeling cross-check findings.  Analysis of the Transport Rule modeling by the Midwest Ozone Group that was co-funded by MP indicates that the nonattainment areas identified by EPA as significantly impacted by Minnesota emissions are modeled to come into attainment with the ozone and PM2.5 daily and annual NAAQS with no further reductions beyond what is already being required for the current CAIR state reductions using the most recent ground level air quality data. EPA should remodel their Transport Rule determinations to use the more current data before assigning more control obligations i.e. to Minnesota, affirming that the nonattainment areas examined for the Transport Rule are still projected to be in nonattainment in 2012.  [EPA-HQ-OAR-2009-0491-2750.1, p.8]
Response:
As part of the final rule EPA has remodeled state contributions to nonattainment and maintenance using a modeling platform with updates based on comments on the proposed rule.  The results of the updated contribution modeling are in section V.D.2 of the preamble. Response to comments on the use of most recent air quality data and on the modeling by the Midwest Ozone Group are in section V.C.2 of the preamble.
Organization: New York State Department of Environmental Conservation
Comment:
New York State Department of Environmental Conservation
Methodology to Project Attainment/Interference with Maintenance Based on CAMx Modeling
For projecting future average/maximum design values for the daily PM2.5 standard, simulated concentrations of the 'other/crustal' component were excluded when determining top 10 percent 'high modeled PM2.5 days' for each quarter for relative response factor (RRF) calculations. This approach points to a disconnect between observed ''high days' and modeled 'high days' which may have implications for the determination of significant contribution and/or nonattainment/maintenance monitors, as well as determining if high observed sulfate/nitrate days correspond to high modeled sulfate/nitrate days. [EPA-HQ-OAR-2009-0491-2730.1, p.11]
Response:
EPA found that the modeled concentrations of the other/crustal component far exceeded the corresponding measured concentrations (see the Air Quality Modeling Technical Support Document Appendix A).  In order to minimize any disconnect between the relative amounts of sulfate and nitrate on high modeled days with that on high measured days, EPA removed the concentrations of the other/crustal component in determining the modeled days to include in the calculation of relative response factors.
Organization: Southern Company
Comment:
Southern Company
EPA should re-run the CAMx model for the 2012 base case with appropriately corrected emissions to determine the corrected air quality contributions for each state to each appropriate (i.e., after considering monitored AND modeled attainment status) downwind monitor in 2012. [EPA-HQ-OAR-2009-0491-2864.1, p. 39]
Response:
EPA has used CAMx to re-model the 2012 base case with the appropriately corrected emissions to determine the air quality contributions for each state to each downwind nonattainment and maintenance receptor in 2012.
Organization: State of Wisconsin, Department of Natural Resources
Comment:
State of Wisconsin, Department of Natural Resources
The air quality modeling platform used by EPA in its assessment of interstate contribution to violating air quality mirrors that used by most regions in support of local attainment demonstrations and is therefore appropriate for assessing Section 110 impacts. In the application of the modeling platform EPA's modeling inventory and adjustments of assessment years and meteorology patterns also appear reasonable. Performance metrics are in line with similar evaluations pursued by states within their regional organizations. [EPA-HQ-OAR-2009-0491-2829.2, p.6]
Response:
EPA agrees that the air quality modeling platform used in the Transport Rule to assess interstate contributions is appropriate for this purpose.
Organization: Sunflower Electric Power Corporation
Comment:
Sunflower Electric Power Corporation
Unlike the reduction in significant contribution found to result from the control of pollutants as identified in Comment 3 above, a similar reduction in significant PM2.5 contribution modeled did not occur at the five Muscatine, IA and Milwaukee, WI receptors which EPA has concluded are significantly influenced by Kansas EGUs. We think, and our consultant alludes to this possibility in the aforementioned report, that the complexity of the atmospheric chemical reactions, at least at the distance from the sources that will result should Kansas sources be included, are not well enough understood to assure that the additional control of Kansas sources will have any significant reduction in air quality at those receptors. [EPA-HQ-OAR-2009-0491-2833.1 p.2]
Because the reductions at the Kansas EGUs referenced in the report will reduce the total SO2 loading from Kansas EGUs by 4%, and the total NOX loading by 44% at an improvement in PM2.5 concentrations of less than 0.34%, one might reasonably conclude that the complete elimination of the entire SO2 and NOX loading from EGUs in Kansas would result in an insignificant improvement in the PM2.5 concentrations in those distant cities. Thus the complete elimination of the EGU sources would still result in the Kansas EGUs as being judged to still have a significant impact on the air-sheds when the sources no longer exist. It seems to us at least that this is an absurd outcome brought about by the extension of incomplete information using modeling methods that have unknown algorithms and which on the surface produce more questions than have yet been answered. [EPA-HQ-OAR-2009-0491-2833.1 p.2]
We respectfully request that EPA reconsider the implications of outcomes such as those presented by our consultant and not rush to regulate where such questions still exist. At a minimum this information should lead to a further extension of the comment period to evaluate further the implications of the determinations thus far made by EPA. [EPA-HQ-OAR-2009-0491-2833.1 p.3]
Response:
EPA has conducted revised air quality modeling with updates based on comments on the modeling platform used for the proposed rule including the EGU reductions referenced by the commenter (needs to be confirmed by CAMD).
The results of the modeling by Trinity referenced by the commenter indicates that Kansas contributes PM2.5 above the 1 percent of the NAAQS threshold to nonattainment of the 24-hour PM2.5 NAAQS in Milwaukee.  This finding is consistent with the results of EPA's updated air quality modeling for contributions of annual NOx and SO2 emissions from Kansas and that Kansas.
Organization: West Virginia Department of Environmental Protection
Comment:
West Virginia Department of Environmental Protection
WVDAQ finds it difficult to believe that EPA has determined that West Virginia significantly contributes to non-attainment St. Louis, Missouri. We believe that EPA needs to provide more explanation when model results are blatantly counter to expected outcomes. [EPA-HQ-OAR-2009-0491-2790.1, p. 7]
Response:
EPA performed a back trajectory analysis to identify the 3-day upwind transport history of air parcels crossing the Madison county, Missouri (East St Louis) monitoring site on days with measured exceedances of the 24-hour PM2.5 NAAQS at this location during 2005 (the year of meteorology modeled for the Transport Rule) and in other years during the period 2003 through 2007 (see Air Quality Modeling Technical Support Document).  The results indicate that there are exceedance days in 2005 when the air arriving in Madison county is likely to have traversed portions of West Virginia within 3 days of arriving in this county.  The trajectory analysis provides qualitative evidence that corroborates the result of EPA's modeling which links emissions in West Virginia to nonattainment for 24-hour PM2.5 in Madison county, Missouri.

IV.C.4. What Are Estimated Interstate Contributions to Annual PM2.5, 24-Hour PM2.5, and 8-Hour Ozone Nonattainment and Maintenance?

Organization: Florida Municipal Electric Association (FMEA)
Comment:
Florida Municipal Electric Association (FMEA)
In addition, the model projections of significant impacts appear to defy common sense. For example, it is hard to imagine that Florida emissions could result in a significant impact on non-attainment on Texas. [EPA-HQ-OAR-2009-0491-2731.1, p. 10]
Response:
Based on the air quality modeling for the Final Transport Rule, Florida contributes to 8-hour ozone in amounts at or above the 0.8 ppb threshold to a total of 26 monitoring sites in 6 other States (i.e., Alabama, Georgia, Louisiana, Mississippi, South Carolina, and Texas).  However, only 2 of these sites, both in Harris county, Texas are projected to be nonattainment and/or have maintenance problems for the 1997 8-hour ozone NAAQS for 2012 base case and are, therefore, relevant receptors for the Transport Rule.
EPA performed a back trajectory analysis to identify the 3-day upwind transport history of air parcels crossing the Harris county, Texas (Houston) 2012 nonattainment and/or maintenance monitoring sites on days with measured exceedances of the 8-hour ozone NAAQS at this location during 2005 (the year of meteorology modeled for the Transport Rule) and in other years during the period 2003 through 2007.  The results indicate that there are ozone exceedance days in 2005 when the air arriving in Harris county is likely to have traversed portions of Florida within 3 days of arriving in this county.  The trajectory analysis provides qualitative evidence that corroborates the results of EPA's modeling which link emissions in Florida to nonattainment/maintenance for 8-hour ozone in Texas.
Organization: Minnesota Power
Comment:
Minnesota Power
Basis for EPA's change in their analysis of the Minnesota contribution to nonattainment.  When EPA's own analysis now posts the Minnesota nonattainment area contribution at 0.19 ug/m3, EPA does not clarify whether the shift from their earlier analysis is due to correction of EPA CMAQ modeling bias resulting from older model version mass stability errors or from EPA's revisiting and correction of CAIR modeled Minnesota unit emission rates.  Absent such information, Minnesota Power is hampered in doing an assessment of the technical support document for the Transport Rule and related review of the NODA. [EPA-HQ-OAR-2009-0491-2750.1, p.7]
Response:
See section IX.A of the preamble for the major differences between the Transport Rule and CAIR.  There are numerous technical differences between the air quality analysis for CAIR and the Transport Rule.  The central technical components that differ between CAIR and the Transport Rule include changes to: (1) the modeling platform including the meteorology, base and future emissions, and air quality model. (2) the future analytic year, and (3) the metrics and thresholds for measuring and evaluating interstate contributions.

IV.C.5. Proposed Geographic Coverage (States Covered)

Organization: Clean Air Task Force
Comment:
Clean Air Task Force
[These comments were submitted as testimony at the Philadelphia, Pennsylvania public hearing on August 26, 2010.  See Docket Number EPA-HQ-OAR-0491-1938, p.106.]
and to include Texas and several other states in the control region.
Response:
The final rule identifies Texas as a state with emissions that significantly contribute to or interfere with maintenance of the 1997 ozone NAAQS and the 1997 and 2006 PM2.5 NAAQS.
Organization: Kansas City Power and Light Company (KCP&L)
Comment:
Kansas City Power and Light Company (KCP&L)
1. The State of Kansas has been included in the PTR for ozone season NOx based on modeled emission rates projected using the Integrated Planning Model (IPM) v3.02.  Revised emission projections were developed and incorporated into CAMx by Trinity Consultants. A full copy of the final report is attached. It was concluded that, after the Jeffrey Energy Center emission rates were corrected, Kansas no longer makes a significant contribution to any ozone monitoring site included in the PTR and should not be included in the Transport Rule for ozone season NOx. [EPA-HQ-OAR-2009-0491-2709.1, p.3]
[The Attachment can be found at the end of this comment.]
Response:
EPA has conducted revised air quality modeling with updates based on comments on the modeling platform used for the proposed rule including corrections to the emissions rates at the Jeffrey Energy Center (need someone from CAMD to confirm this).
The final transport rule analysis does not identify Dallas as a nonattainment or maintenance receptor.  This analysis, however, does identify Kansas as a state with emissions that interfere with maintenance in Allegan County, MI.  For reasons explained therein, EPA is issuing a Supplemental Notice of Proposed Rulemaking to propose that states (including Kansas) to take comment, among other things, on its conclusion that Kansas significantly contributes to or interferes with maintenance of the 1997 ozone NAAQS in another state.
Organization: Louisiana Energy and Power Authority (LEPA)
Comment:
Louisiana Energy and Power Authority (LEPA)
LEPA understands that other commenters, including the Louisiana Department of Environmental Quality and the Louisiana Chemical Association, have performed an analysis that demonstrates that the proposed Transport Rule should not apply to Louisiana because there is no proof that emissions in Louisiana contribute to non-attainment or maintenance of air quality standards in any neighboring state. LEPA has not conducted an independent analysis of this because it lacked the time and resources to do so in the very limited timeframe the EPA allowed for review and comment, but LEPA agrees with those comments and urges the EPA to revise its proposed Transport Rule to exclude Louisiana. [EPA-HQ-OAR-2009-0491-2700.1, p.2]
Response:
For the Final Transport Rule EPA has conducted revised air quality modeling with updates based on comments on the modeling platform used for the proposed rule.  Based on the updated modeling, Louisiana is not identified in the final rule as a state with emissions that significantly contribute to or interfere with maintenance of the 1997 or 2006 PM2.5 NAAQS.  However, the updated modeling continues to show that emissions in Louisiana contribute to nonattainment and maintenance of the 1997 8-hour ozone NAAQS in Houston.   Thus, Louisiana continues to be included in the Transport Rule for ozone season NOx emissions reductions.
Organization: Luminant
Comment:
Luminant
:: Luminant has concerns, however about the proposed area of impact under the NOx program for Texas. Baton Rouge has just demonstrated attainment for the 1997 ozone standard. Therefore, it is inappropriate to include Texas in the ozone season NOx program. [EPA-HQ-OAR-2009-0491-2729.1, p.2]
:: Furthermore, back trajectories of winds in Texas, generated by the National Oceanic and Atmospheric Administration (NOAA) and used in SIP planning, show that northwest winds are infrequent. Therefore, most of the EGUs in the state should have little impact on ozone in Baton Rouge, and it is inappropriate to conclude that Texas emissions have an impact on Baton Rouge attainment status. [EPA-HQ-OAR-2009-0491-2729.1, p.2]
IV. Texas Should Not Be Included in the Ozone Season NOx Program
EPA proposes to include Texas in the ozone season NOx program because the IPM model indicates that Texas will contribute significantly to the Baton Rouge ozone nonattainment area. However, on September 9, 2010, EPA published a final rule (75 Fed. Reg. 54778) determining that the Baton Rouge area had met the 1997 ozone standard and was in attainment. [EPA-HQ-OAR-2009-0491-2729.1, p.6]
Meteorological back trajectories of wind generated by NOAA and used in SIP planning for the Dallas-Fort Worth areas show that winds from the northwest are the least frequent, especially in ozone season. Logic would dictate that most power plants in Texas would have limited impact on Baton Rouge. In addition, EPA did not appear to include in the modeling all of the NOx and volatile organic compound (VOC) reductions that have been made in the Houston area. Thus, there is no logical basis for concluding that Texas emissions will impact Baton Rouge's attainment status. Thus, Texas should not be included in the ozone season NOx program. [EPA-HQ-OAR-2009-0491-2729.1, p.6]
Response:
EPA continues to believe that measured concentrations during the period 2003 through 2007 provide the appropriate air quality starting point for projecting future nonattainment and maintenance for the purposes of the Transport Rule (see preamble section V.C.2).  EPA has updated the air quality modeling platform based on comments (see preamble section V.D.2) and the results of the updated modeling for the 2012 base case combined with measured ozone concentrations during 2003 through 2007 continue to show that Baton Rouge is projected to be nonattainment of the ozone NAAQS in 2012 without CAIR.   The updated contribution modeling continues to show that Texas contributes to ozone in Baton Rouge by an amount that exceeds the 1 percent of the NAAQS contribution threshold employed for the Transport Rule and that sources in Texas have emissions reductions available at the cost thresholds identified.  Thus, Texas continues to be included in the Transport Rule for an ozone season NOx budget.   In addition, EPA has  performed a back trajectory analysis to identify the 3-day upwind transport history of air parcels crossing Baton Rouge, Louisiana  on days with measured exceedances of the 8-hour ozone NAAQS at this location in 2005 (the year of meteorology modeled for the Transport Rule) and in other years during the period 2003 through 2007 (see Air Quality Modeling Technical Support Document).  The results of this analysis indicate that there are exceedance days in 2005 and in other years when the air arriving in Baton Rouge is likely to have traversed portions of Texas within 3 days of arriving in this parish.  The trajectory analysis provides qualitative evidence that corroborates the result of EPA's modeling which links emissions in Texas to nonattainment for the 8-hour ozone NAAQS in Baton Rouge.
Organization: PPG Industries, Inc.
Entergy Services, Inc.
Dow Chemical Company
Comment:
Dow Chemical Company
Dow believes that EPA's finding that Louisiana emission sources interfere with maintenance of the annual PM2.5 standard in Harris Co., Texas is erroneous, for the reasons stated in the comments of the Louisiana Chemical Association on the proposed Transport Rule and FIP. Dow hereby adopts those comments by reference. The one monitor in Harris County allegedly impacted by Louisiana emissions is in compliance with the annual PM2.5 NAAQS and annual average emissions for the past two years have been below 14.0 ug/m3. As EPA's own projections indicate that SO2 and NOx emissions from Louisiana EGUs will decline by 2012 even without the Transport Rule/FIP, there is no legal basis for imposition of a FIP. Dow requests that EPA delete the annual SO2 and NOx requirements from the proposed rule and FIP for Louisiana EGUs.  [EPA-HQ-OAR-2009-0491-2775.1 p.2]
Entergy Services, Inc.
Applicability of Clean Air Transport Rule to Louisiana
1. EPA Proposed Finding of Interference With Maintenance of Annual PM2.5 NAAQS
Entergy adopts comments I.B and I.C made by the Louisiana Chemical Association. Entergy does not believe that the state of Louisiana is interfering with the maintenance of PM2.5 attainment in downwind states.  Louisiana, therefore, should not be regulated in the annual program in the final rule.  In the proposed rule, Louisiana is in the annual program because of a 0.34 μg/m3 PM2.5 contribution to one monitor (Clinton Drive monitor) in Harris County, TX.  Since 2004, all PM2.5 monitors in the Houston area except the Clinton Drive monitor have recorded readings less than 15.0 μg/m3.  PM2.5 data for the Clinton Drive monitor showed a 2005 annual average of 15.9 μg/m3 and a three-year average of 15.0 μg/m3.  The Texas Commission on Environmental Quality (TCEQ) conducted an advanced analysis of the PM2.5 data, meteorological data, and the chemical speciation data to identify the cause (what portion and component of PM2.5), source types, and source areas contributing to the excessive particulate matter concentrations.  Daytime, weekday concentrations are the main cause of high PM2.5 levels at the Clinton Drive site.  Analysis of chemical speciation data shows the calculated mass of soil at Clinton Drive is approximately 1.5 to 2.0 μg/m3 higher than at any other speciation monitoring site in the Houston area.  The data indicates that the higher elevated PM2.5 concentrations at the Clinton Drive monitor represent a limited area that is impacted by local fugitive emissions, as the Clinton Drive monitor is located directly across from the entrance to the Port of Houston Authority (PHA) and unpaved ship yards along the Houston Ship Channel.  A railroad also runs parallel to this section of Clinton Drive. [EPA-HQ-OAR-2009-0491-2847.1, p.6]
Concurrently, the TCEQ began working with the PHA, the City of Houston, Harris County, and local industry to address this issue.  The combined efforts of the various organizations has improved particulate matter air quality to the point that the 2008 PM2.5 annual average at Clinton Drive was 14.0 μg/m3, even when exceptional event days are included. Without removing exceptional event days, the 2006 through 2008 design value for Clinton Drive was 15.2 μg/m3. After removing exceptional event days identified by TCEQ meteorologists, the 2006 through 2008 design value was 14.6 μg/m3.  Without removing exceptional event days, the 2007 through 2009 design value for Clinton Drive was 14.1 μg/m3.  The annual readings for the Clinton Drive monitor show a steady decline during the last 4 years.  [EPA-HQ-OAR-2009-0491-2847.1,p.7]
2006  -  16.0 μg/m3
2007  -  15.6 μg/m3
2008  -  14.0 μg/m3
2009  -  12.6 μg/m3
This data demonstrates that the PM2.5 issue at the Clinton Drive monitor was caused by local conditions and that those local corrective actions had improved the air quality to an attainment status.   [EPA-HQ-OAR-2009-0491-2847.1, p.7]
Realizing that the PM2.5 issues at the Clinton Drive monitor are a local problem, and in anticipation of the strengthening of the NAAQS for PM2.5, a taskforce committee consisting of members from the TCEQ, Texas Department of Transportation (TxDOT), Harris County, the City of Houston, the PHA, and the Houston-Galveston Area Council was organized to address this issue. The taskforce committee established a scope for projects on Clinton Drive that prevent disturbing PM2.5 dust and will ensure these local issues are addressed.  See Attachments Clinton Drive 1, Clinton Drive 2, Clinton Drive 3, Clinton Drive 4.  [EPA-HQ-OAR-2009-0491-2847.1,p.7] [[See Docket Numbers [EPA-HQ-OAR-2009-0491-2847.3 thru EPA-HQ-OAR-2009-0491-2847.6 for Attachments.]]
Because the pollution causing the only purported Transport Rule related exceedences connected to Louisiana was caused by local conditions, these local conditions have been addressed,  these conditions will continue to be addressed in the future, and the monitor is now demonstrating attainment of the PM2.5 standard, Louisiana should not be in the annual program of the Clean Air Transport Rule.  [EPA-HQ-OAR-2009-0491-2847.1, p.7]
Furthermore, even if there were a downwind transport problem of NOx and SO2 from Louisiana, Table IV.C-1-2005 Base Case SO2 Emissions (Tons/Year) For Eastern States By Sector and Table IV.C-2-2005 Base Case NOx Emissions (Tons/Year) For Eastern States By Sector in the proposed rule, clearly indicate that the regulation of EGU's in Louisiana is not the solution to solving the problem, as EGU emissions for those pollutants in Louisiana are considerably less than non-EGU emissions of each pollutant. [EPA-HQ-OAR-2009-0491-2847.1, p.7]
In summary, EPA's own modeling shows that without the Transport Rule/FIP, overall emissions of SO2 in Louisiana will decrease by 12,758 tpy from 2005 levels by 2012 and by 26,618 tpy from 2005 levels by 2014.  As discussed above, Harris County, Texas is currently in attainment with the annual PM2.5 NAAQS and has a strong downward trend of PM2.5 emissions over the past several years.   If Louisiana SO2 emissions are not causing interference with maintenance now, and are projected to have this significant of a decrease of SO2 without the Transport Rule, then how can EPA reasonably conclude that Louisiana is likely to interfere with maintenance of the PM2.5 standard in Harris County or that the Transport Rule is justified for Louisiana?  If greater emissions are not affecting maintenance, then how can lesser emissions affect maintenance? Entergy believes that it would be arbitrary and capricious for EPA to arrive at this as a final conclusion.  [EPA-HQ-OAR-2009-0491-2847.1,p.11]
As can be seen by this data, EPA also projects that these NOx emissions will decrease by 108,775 tpy (a 16% decrease), even without the Transport Rule/FIP.  As noted above, EPA's modeling demonstrates that Louisiana NOx emissions appear to have almost no impact on the resulting levels of PM2.5 in Harris County, Texas as the nitrate component of the Louisiana impact was only 0.004 ug/m3.  Thus, there is no reason to expect that NOx emissions will contribute to interference with attainment in Harris Co., Texas in the future as they are not causing interference now.  [EPA-HQ-OAR-2009-0491-2847.1, p.11] [[See Docket Number EPA-HQ-OAR-2009-0491-2847.1, p.11 for the data.]]
Moreover, actual certified SO2 and NOx data submitted to EPA's Clean Air Markets Division pursuant to the Acid Rain and CAIR programs confirms a significant decline in actual SO2 and NOx reductions statewide from Louisiana EGUs over the past five years:  [EPA-HQ-OAR-2009-0491-2847.1, p.12] [[See Docket Number EPA-HQ-OAR-2009-0491-2847.1,p.12 for a figure.]]
In fact, actual certified totals of SO2 and NOx in 2009 were already well below the values projected by EPA for the Base Case 2012 and 2014 levels for Louisiana EGUs, whether projected by TR Base Case v.3.02 or v.4.10.
While Entergy has not been able to complete its review of the changes to the TR Base Case v. 4.10 compared to TR Base Case v. 3.02, nor of the evaluation of different Transport Rule FIP options using version 4.10, it is imperative for EPA to realize that the total SO2, annual NOx and ozone season NOx estimates under the TR Base Case v. 4.10 have dropped dramatically when compared to the TR Base Case v. 3.02.  The reduction in each case is greater than the difference between the TR Base Case v. 3.02 and the TR SB Limited Trading Values.  This difference is what EPA has stated to be the amount to be removed in order to prevent "significant contribution" or "interference with attainment."  In short, this means that EPA projects with the updated version of the IPM that by 2012, the total reduction required in order to prevent any significant contribution or interference with maintenance has already been achieved without the Transport Rule/FIP.  The following Table makes that comparison:  [EPA-HQ-OAR-2009-0491-2847.1, p.12] [[See Docket Number EPA-HQ-OAR-2009-0491-2847.1, pp.12-13 for the table.]]
Because "significant contribution" and "interference with maintenance" have been removed with this revised IPM modeling, there is no basis for a Transport Rule or FIP for Louisiana EGUs, as the levels required to remove significant contribution and interference with maintenance will have already been achieved.  In summary, EPA's IPM modeling provides no rational basis for the FIP proposed for Louisiana.  It supports a conclusion that any potential Louisiana impact on either annual PM2.5 or 8-hour ozone NAAQS in Texas will be removed through factors other than the Transport Rule and CAIR. [EPA-HQ-OAR-2009-0491-2847.1, p.13]
PPG Industries, Inc.
PPG believes that Louisiana should not be included within the proposed rule and FIP for annual SO2 and NOx reductions because Louisiana emission sources do not reasonably have the potential to interfere with the ability of Harris County, Texas, to maintain its current attainment with the annual PM2.5 NAAQS, contrary to EPA's proposal. PPG needs additional time to gather and present data to EPA on this critical issue. [EPA-HQ-OAR-2009-0491-1926.1, p.2]
Response:
EPA has conducted revised air quality modeling with updates based on comments on the modeling platform used for the proposed rule.  In the revised modeling there are no monitoring sites in Texas with projected 2012 base case nonattainment or maintenance problems for the annual PM2.5 NAAQS.   In addition, Louisiana is not included in the final Transport Rule for reductions of annual SO2 and NOx emissions.
Organization: Sierra Club, Pennsylvania Chapter
Comment:
Sierra Club, Pennsylvania Chapter
With this proposal, Pennsylvania can finally become a "Good Neighbor" to the states that surround it geographically in the Mid-Atlantic region, and in fact, states hundreds of miles down wind. We support the regional nature of these reductions and we believe that this regional focus should be expanded. [EPA-HQ-OAR-2009-0491-3482.1, p.2]
An EPA's analysis identifies 10 states that send pollution to Pennsylvania, using measured data captured in those state's own air monitors. Not only Indiana, Michigan and Wisconsin, but Illinois, Kentucky, Ohio, Georgia and Missouri send ozone and particles into Pennsylvania. This rule would require that plants in 31 states -- including Pennsylvania -- cut pollution they send across state lines. We believe that there are additional states that should be included in this process; please include Texas, Arkansas, New Hampshire, North Dakota and Oklahoma in the control region for SO2 and annual NOx reductions, and include Massachusetts and Missouri in the control region for ozone season NOx reductions. [EPA-HQ-OAR-2009-0491-3482.1, p.5]
- include Texas, Arkansas, New Hampshire, North Dakota and Oklahoma in the control region for SO2 and annual NOx purposes, and include Massachusetts and Missouri in the control region for ozone season NOx purposes. [EPA-HQ-OAR-2009-0491-3482.1, p.7]
Response:
EPA conducted an objective, quantitative, air quality-based analysis to identify upwind states that contribute amounts of ozone and/or PM2.5 above threshold concentrations to projected 2012 base case downwind nonattainment and/or maintenance receptors.  The results of this analysis were part of the basis for identifying states included in the final Transport Rule for ozone season NOx reductions and/or annual NOx and SO2 emissions reductions.   Based in part on this analysis Texas is included for ozone season NOx reductions and annual NOx and SO2 emissions reductions and Arkansas is included for ozone season NOx reductions.  Missouri is included for annual NOx and SO2 emissions reductions.   Oklahoma and Missouri are proposed to be included for ozone season NOx reductions as part of a Supplemental Notice of Proposed Rulemaking.  Of the other states identified by the commenter, New Hampshire, North Dakota and Massachusetts are not included in the Transport Rule for ozone season NOx reductions or annual NOx and SO2 emissions reductions.
Organization: Texas Commission on Environmental Quality
Occidental Chemical Corporation (OCC)
Comment:
Occidental Chemical Corporation (OCC)
Moreover, we seriously question why the state of Texas is included in this rulemaking, given that the downwind state (Louisiana) has improved ambient air quality such that it does not have any ozone non-attainment areas. As set forth in greater detail below, OCC strongly believes that neither Louisiana nor Texas should be included in the final CATR. [EPA-HQ-OAR-2009-0491-2754.1, p. 3]
Texas Commission on Environmental Quality
The TCEQ finds that Texas should not be identified as a significant contributor to any nonattainment areas for the 1997 eight-hour ozone standard. [EPA-HQ-OAR-2009-0491-2857.1, p.1]
Texas should not be identified as significantly contributing to any nonattainment areas for the 1997 eight-hour ozone standard.
Because the premises on which Texas' inclusion in the Transport Rule trading program is based are substantially flawed and rely on incorrect data, Texas should not be included in the Transport Rule program. [EPA-HQ-OAR-2009-0491-2857.2, p.3]
Finally, the TCEQ objects to the inclusion of Texas in the Transport Rule program, based on flaws in the EPA's technical analysis for the program and the fact that the only area to which Texas is linked for significant contribution to nonattainment (Baton Rouge, LA) has recently been determined in attainment of the 1997 eight-hour ozone NAAQS by the EPA. [EPA-HQ-OAR-2009-0491-2857.1, p.3]
Response:
EPA continues to believe that measured concentrations during the period 2003 through 2007 provide the appropriate air quality starting point for projecting future nonattainment and maintenance for the purposes of the Transport Rule (see preamble section V.C.2).  EPA has updated the air quality modeling platform based on comments (see preamble section V.D.2) and the results of the updated modeling for the 2012 base case combined with measured ozone concentrations during 2003 through 2007 continue to show that Baton Rouge is projected to be nonattainment of the ozone NAAQS in 2012 without CAIR.   The updated contribution modeling continues to show that Texas contributes to ozone in Baton Rouge by an amount that exceeds the 1 percent of the NAAQS contribution threshold employed for the Transport Rule and that sources in Texas have emission reductions available at the cost thresholds identified..  Thus, Texas is identified as a state with emissions that significantly contribute to or interfere with maintenance of the 1997 ozone NAAQS.
Organization: Western Farmers Electric Cooperative (WFEC)
Comment:
Western Farmers Electric Cooperative (WFEC)
the State of Oklahoma was not included in the original CAIR program but has been included with CATR during Ozone season. Why did it change?  It is our understanding that the state of Oklahoma was only included because of one modeling day in which the Dallas - Fort Worth (DFW) area was affected by Oklahoma emissions.  Since southerly winds are predominately and Oklahoma is north of DFW, it seems unwarranted to place such a heavy financial burden on the electrical consumers in Oklahoma.  [EPA-HQ-OAR-2009-0491-2642.1, p.3]
Response:
See section IX.A of the preamble for the major differences between the Transport Rule and CAIR.  The central technical components that differ between CAIR and the Transport Rule include changes to: (1) the modeling platform including the meteorology, base and future emissions, and air quality model. (2) the future analytic year, and (3) the metrics and thresholds for measuring and evaluating interstate contributions.
For reasons explained therein, EPA is issuing a Supplemental Notice of Proposed Rulemaking to take comment, among other things, on its conclusion that Oklahoma has emissions that significantly contribute to nonattainment or interfere with maintenance of the 1997 ozone NAAQS in another state.

IV.D. Proposed Methodology to Quantify Emissions That Significantly Contribute or Interfere With Maintenance

Organization: American Public Power Association (APPA)
Florida Electric Power Coordinating Group, Inc. (FCG)
Comment:
American Public Power Association (APPA)
EPA has failed to propose a defensible methodology for determining statewide emission reduction obligations and has required additional emission reductions even where they have not been shown to be needed to meet the air quality objectives that EPA asserts. [EPA-HQ-OAR-2009-0491-2812.1, p.7]
EPA indicated in a presentation given in July 2010, when it announced the proposed rule, that it projects that the proposed rule would reduce SO2 emissions by an additional one million tons per year ("TPY") in 2012 beyond what CAIR would have accomplished: from an emission level of 5.1 million TPY under CAIR to 4.1 million TPY under the proposed rule. See Overview Presentation 7/26/10 at slide 33, available at http://www.epa.gov/airquality/transport/actions.html. [EPA-HQ-OAR-2009-0491-2812.1, p.17]
In fact, during a meeting held shortly after EPA issued the proposed rule but before its publication in the Federal Register, EPA acknowledged that, according to the Agency`s projections, the 2012 state budgets in the Proposed Transport Rule would reduce SO2 emissions by 1.2 million TPY, from 5.1 million TPY under CAIR to 3.9 million TPY under the Proposed Transport Rule. EPA failed to explain this apparently substantial discrepancy or how over a million additional tons of emissions would be eliminated in a phase of the program that is intended merely to replicate what would have occurred anyway. [EPA-HQ-OAR-2009-0491-2812.1, p.17]
EPA has not shown that emission reductions beyond those required by CAIR are necessary. EPA`s own data show that existing controls are working to reduce emissions; the result is that concentrations of SO2 and NOx in the ambient air have declined steadily in recent years. The D.C. Circuit`s opinion in North Carolina v. EPA did not require, or even imply that the overall degree of emission reductions required under CAIR was less than that necessary to comply with CAA section 110(a)(2)(D)(i)(I). Nor did the court include in its opinion any mandate that the replacement rule for CAIR must include a compliance date in 2012 or within any period of time as short as six months after final rule promulgation. 12 [EPA-HQ-OAR-2009-0491-2812.1, p.18]
In light of this, EPA should decide not to call for the steep additional emission reductions demanded by the PTR because such reductions are not needed to reduce significant regional contributions to downwind nonattainment. [EPA-HQ-OAR-2009-0491-2812.1, p.32]
Florida Electric Power Coordinating Group, Inc. (FCG)
Notwithstanding EPA's assertion that the emission reductions required in 2012 would occur even without the Proposed Transport Rule, a presentation given by EPA in July indicated that the proposal would reduce S02 emissions by an additional one million tons per year ('TPY') in 2012 beyond what the Clean Air Interstate Rule (CAIR) would have accomplished: from a level of 5.1 million TPY under CAIR to 4.1 million TPY under the proposed rule. In fact, during a meeting held shortly after the proposed rule was issued, the Director of EPA's Clean Air Markets Division acknowledged that the 2012 state budgets in the Proposed Transport Rule would reduce S02 emissions by 1.2 million TPY, from 5.1 million TPY under CAIR to 3.9 million TPY under the Proposed Transport Rule. EPA must explain this apparent discrepancy and how over a million tons of emissions would be eliminated by relying on controls already in use. [EPA-HQ-OAR-2009-0491-2658.1, p.3]
Response:
In EPA's assessment of significant contribution to non-attainment and inference with maintenance for the final Transport Rule, EPA utilized the most recently available information on emissions and existing controls.  This assessment is based on the best data available and reflects the current state of the electricity generation sector.  Regarding forecast emissions under CAIR, EPA finds that based on real world information, the electricity generation sector is doing more to reduce SO2 emissions (such as installing scrubbers, switching to lower sulfur coal, and fuel switching to gas) than was forecast at the time of CAIR's promulgation.  Additionally, when comparing projected emissions between the Clean Air Interstate Rule and the final Transport Rule, it is important to keep in mind that CAIR included a large bank of SO2 allowances carried over from the Acid Rain Program.  The Court in its decision in North Carolina found EPA's decision to base state budgets on existing ARP allowances to be unlawful and determined that EPA could not, through a 110(a)(2)(D)(i)(I) rule terminate or modify ARP allowances.
Organization: Attorney General of North Carolina
Comment:
Attorney General of North Carolina
In CAIR, EPA declined to evaluate any attainment areas to determine if upwind emissions would interfere with maintenance of the National Ambient Air Quality Standards in those areas. The D.C. Circuit held that EPA cannot simply refuse to apply the "interfere with maintenance" prong of §110(a)(2)(D)(i)(I) and arbitrarily deny deserving downwind attainment areas protection from upwind sources that threaten their attainment of the NAAQS.
In response, EPA has developed a methodology to assess whether areas need assistance from upwind sources in order to maintain the NAAQS and has based certain reductions in the Transport FIP on its determination that certain areas require such assistance. North Carolina believes that EPA has adequately complied with the Court's mandate that it not read the "interfere with maintenance" language out of the statute.
In North Carolina, the Court declined to assess whether EPA's methodology for implementing the maintenance standard complied with the statute. North Carolina takes no position here on whether EPA's new methodology complies with the statute, except to submit that that EPA's implementation is incomplete.
In 2004, North Carolina filed a petition under §126 of the Clean Air Act. 42 U.S.C. §7426. The petition was based in part on North Carolina's conclusions that out-of-state sources were contributing significantly to nonattainment of the ozone NAAQS in North Carolina and were interfering with North Carolina's maintenance of that standard. EPA denied the petition regarding the ozone NAAQS because EPA projected that North Carolina would attain the ozone standard without the need for reductions in upwind States. Rulemaking on §126 Petition from N.C. to Reduce Interstate Transport of Fine Particulate Matter & Ozone, 71 Fed. Reg. 25,328, 25,337/1 (2006).
In 2006, North Carolina petitioned for judicial review of EPA's denial of the petition. See Sierra Club, No. 06-1221 (D.C. Cir.). By late 2008, EPA concluded that, contrary to its own projection that North Carolina would fully attain the ozone standard by the required attainment date of 2010, in the Charlotte area "attainment will not be achieved by the required moderate area deadline . . . ." Ltr. from J.I. Palmer, Reg'l Adm'r, EPA Region 4, to Sec'y W.G. Ross, N.C. Dept. of Envt. & Natural Resources at 1 (Nov. 17, 2008) [hereinafter "EPA Ltr."]; see also Ltr. from J.I. Palmer, Reg'l Adm'r, EPA Region 4, to Sec'y W.G. Ross, N.C. Dept. of Envt. & Natural Resources (Jan. 9, 2009). Based on this conclusion, EPA requested that the Court remand the matter to EPA for reconsideration in light of the changed facts. EPA, Supplemental Filing Requesting Remand, Sierra Club v. EPA, No. 06- 1221 (D.C. Cir. Feb. 23, 2009). On March 5, 2009, the Court issued its Judgment: EPA . . . concedes the factual predicate for denying North Carolina's petition as to ozone has fundamentally changed, and confirms that regardless of what this Court might decide based on the facts as then found by EPA, the Agency will reconsider its denial of North Carolina's petition in light of these new facts. Judgment, Sierra Club v. EPA, No. 06-1221, at 1-2 (D.C. Cir. March 5, 2009). Therefore, the Court remanded the matter to EPA for reconsideration. Despite the Court's admonishment that "this reconsideration should be expeditious" and the Court's reference to the sixty-day decisional deadline Congress included in §126, id. at 2, EPA has taken no formal action on the petition in over a year and a half.
The point here is that EPA recognized that the modeling in that case was "extremely complex and contain[ed] some uncertainty in the predictions." EPA Ltr. at 1. As the facts bore out, the modeling was incorrect and North Carolina was denied relief to which it was entitled.
Given this experience, North Carolina submits that EPA should build into the Transport FIP and CAIR's replacement safeguards to ensure that downwind areas are not inappropriately denied relief, as North Carolina was, based on projections that turn out to be incorrect and unfairly handicap downwind areas. North Carolina respects the need for regulatory certainty and administrative finality. However, the overriding concern is that established by Congress, which is to provide appropriate and timely upwind controls in order to alleviate unfair burdens on downwind States. In order to avoid regulatory delays that would prolong the deprivation of benefits to downwind areas, EPA should promulgate automatic triggers based on downwind air quality conditions or establish an expedited process to provide the necessary protections to downwind areas.
Therefore, North Carolina recommends that EPA provide for a "true up" of the air quality projections at such times as would be necessary and appropriate to fully implement Congress' mandate under §110(a)(2)(D)(i)(I) for timely elimination of upwind emissions that violate the twin test regarding nonattainment and maintenance.
This is not an idle request. The Charlotte area may very well attain the 85 ppb ozone standard in 2010. This would occur in no small measure due to the 2009 fourth-highest monitored value at the County Line monitor of 71 ppb, which would be part of the three-year average evaluated for attainment in 2010 and 2011. In the fifteen years prior to 2009, the fourth-highest value at this monitor exceeded 85 ppb every year except 2004, when it dipped a mere 2 ppb below the standard. In all but two of those fifteen years it recorded levels of 90 ppb or higher. Provisional data to date in 2010 yields a fourth-highest reading of 82 ppb. If this number holds it would be the second lowest ever recorded at the County Line monitor.
The 71 ppb recorded in 2009 is, historically speaking, an exceedingly low number and the current 2010 level would also be lower than normal. Although these recent data are undoubtedly beneficial from both a health and welfare perspective and in terms of regulatory compliance, whether these trends will continue is uncertain. NOX emissions across the southeast in 2009 fell considerably, but regional heat input levels also tumbled, suggesting that at least part of the regional NOX declines in both 2009 and 2010 were due to economic considerations and not NOX controls. The 2009 data will be included in the 2011 three-year average, but not in the three-year averages for 2012 or subsequent years. Accordingly, even though the Charlotte area may attain by the end of the 2011 ozone season, regional reductions may be necessary to assist Charlotte in maintaining the standard thereafter.7 EPA should consider this in its implementation of §110(a)(2)(D)(i)(I). [EPA-HQ-OAR-2009-0491-2685.1 p.12]
EPA does not appear to have considered retirement of coal units as a control option. Although "EPA projects that approximately 1.2 GW of coal-fired generation may be removed from operation by 2014" this seems to be more an unintended consequence of the proposed rule rather than a purposeful consideration. In fact, EPA notes that "[i]n practice, however" some of "the units . . . may be . . . kept in service . . . ." Id. at 45,357/1. [EPA-HQ-OAR-2009-0491-2685.1]
Consideration of coal unit retirement is necessary to be fair to downwind States. Long ago, in Union Elec. Co. v. EPA, 427 U.S. 246 (1976), the Supreme Court held that downwind States must meet the attainment deadlines regardless of perceived technical infeasibility because the Clean Air Act is a technology-forcing statute. Id. at 255-66 (The words "as expeditiously as practicable but . . . in no case later than three years" as used in the Clean Air Act regarding attainment of the 19 NAAQS leave no room for arguments regarding technological infeasibility); id. at 257 (The requirements of the Clean Air Act "are expressly designed to force regulated sources to develop pollution control devices that might at the time appear to be economically or technologically infeasible"). The Court also observed that no control scenario "is infeasible since offending sources always have the option of shutting down if they cannot otherwise comply with the standard of the law." Id. at 265 n.14. [EPA-HQ-OAR-2009-0491-2685.1]
EPA implements §110(a)(2)(D)(i)(I) by requiring only control s that are both technically and economically feasible. But the D.C. Circuit held that EPA is required to coordinate the upwind reductions with the downwind attainment deadlines. Attainment deadlines, of course, provided the framework for the Supreme Court's holding eschewing claims of technological infeasibility from the equation. Thus, under Union Electric and North Carolina, EPA has an obligation to consider solutions that may seem technologically infeasible. At the very least, EPA must consider unit retirements because, as the Supreme Court indicated, such a remedy is always technologically feasible. [EPA-HQ-OAR-2009-0491-2685.1]
The flaw in EPA's methodology becomes readily apparent when the situation is reduced to a single facility. If a single facility on the State X side of the border between States X and Y were in large part responsible for nonattainment in an area of State Y, yet the facility could not reduce its emissions at a cost level that 20 EPA deemed "highly cost effective," State Y would have no remedy under §110(a)(2)(D)(i)(I) according to EPA. Certainly, Congress would not have enacted a provision to address interstate issues yet leave a deserving State in such a helpless position  -  subject to health and welfare impacts and sanctions for a situation that was virtually entirely out of its control  -  without being clearer.8 The language Congress used in §110(a)(2)(D)(i)(I), on its face, appears to apply to exactly the situation of the hypothetical State Y. EPA's construct for implementing §110(a)(2)(D)(i)(I), which could result in no emissions reductions despite the presence of overwhelming interstate impacts, is at odds with Congress' direct efforts to provide a remedy. [EPA-HQ-OAR-2009-0491-2685.1]
Response: