# Exhibit 13

### Case: 10-1252 Document: 1288492 Filed: 01/18/2011 Page: 1 

### ORAL ARGUMENT NOT YET SCHEDULED UNITED STATES COURT OF APPEALS FOR THE DISTRICT OF COLUMBIA CIRCUIT

NATIONAL ENVIRONMENTAL DEVELOPMENT ASSOCIATION'S CLEAN AIR PROJECT, 

### Petitioner,



### v.
UNITED STATES ENVIRONMENTAL PROTECT ION AGENCY, 

### Respondent. 

### )

Docket No. 10-1252 (and consolidated cases)

DECLARATION OF ROGER W . BRODE 1. My name is Roger W . Brode. I hold B.S. and M .S. degrees in Atmospheric Sciences and I
am currently assigned as a physical scientist in the Air Quality Modeling Group within the Air Quality Assessment Division ofthe Office of Air and Radiation ' s Office of Air Quality Planning and Standards at the U .S. Environmental Protection Agency ("EPA"), where my 1

### Case: 10-1252 Document: 1288492 Filed: 01/18/2011 Page: 2 responsibilities include the development , evaluation and application of air quality dispersion models and the development of guidance associated with application of such models in support ofEPA regulations governing the Prevention o f Significant Deteriora tion ("PSD")_permit ting program. I ha ve been involved in the deve lopment , evaluation , testing, and documentation o f the American Meteorological Society EPA Regulatory Model ("AERMOD " ) throughout its history. I currently serve as co-chair of the AMS/EP A Regulatory Model Improvement Committee (AERMIC) consisting of atmospheric scienti sts and dispersion model experts overseeing the further technical development of the model , and
as co-chair of the AERMOD Implementation Workgroup consisting of EPA Reg ional Office and State dispers ion modelers whose charge has been to indentify and as sess potential is sues with implementation of the AERMOD model as EPA ' s preferred model under Appendix W of Part 51 of the Code ofF ederal Regulations. 2. The revised primary national ambient air quality standard for oxides of sulfur ( " S02 NAAQS " ) requires that the three year average ofthe annual 99 111 percentile of the daily maximum 1-hour average concentrations ofS02 be less than or equal to 75 parts per billion. In addition, owners and operators of a new major stationary source or a major source undergoing a major modification located in areas not designated " nonattainment" for the S02 NAAQS must obtain a PSD permit , and to do so must demonstrate (among other things) that the emissions increases f rom the new or modified source will not cause or contribute to a violation ofthe revi sed S02 NAAQS. Existing air quality models , including AERMOD , are readily capable of accurately predicting whether the revised primary S02 N AAQS is a ttained and whether individual sources cause or contribu t e to a violation of the S02 NAAQS. Specifically , dispersion models that are used to demonstrate compliance with the S02 (and

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### Case: 10-1252 Document: 1288492 Filed: 01/18/2011 Page: 3 other) NAAQS, including under PSD permitting programs, use sequentia l hourly meteorological data as the basis for estimating ambient concentration levels. These data are combined with other inputs (chiefly source emission information, background emissions, and receptor information) to predict transport and dispersion of emitted pollutant plumes. Since the key varying inputs to these models are input on an hourly basis , all applications of these models under the guidance in Appendix W (40 CFR Part 51) are predicated upon the models ' ability to predict hourly amb ient concentrations. These models thus generate one-hour air quality distributions from which the three year average of the annual 99th percentile of daily maximum 1-hour average concentration of S02 can be readily calculated or otherwise reasonably approximated
. 3 . As part ofthe basis for EPA adopting the AERMOD model as the preferred model for nearfield applications in the Guideline on Air Quality Models, Appendix W to 40 CFR Part 51, the performance ofthe AERMOD model was extensively evaluated based on a total of 17 fie ld study data bases (AERMOD: Latest Features and Evaluation Results. EPA

-454/R-03- 003. U.S. Environmental Protection Agency, Research Triangle Park (2003), portions of which are attached to this affidavit) ("EPA 2003") . The scope of the model evaluations conducted for AERMOD far exceeds the scope of evaluations conducted on any other model that has been adopted in Appendix W to Part 51. These evaluations demonstrate the overall good performance of the AERMOD model based on technica ll y sound model evaluation procedures, and also illustrate the significant advancement in the science of dispersion modeling represented by the AERMOD model as compared to other models that have been used in the past. In particular, adoption ofthe AERMOD model has significantly reduced the

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### Case: 10-1252 Document: 1288492 Filed: 01/18/2011 Page: 4 potential for overestimation of ambient impacts from elevated sources in complex terrain compared to other-models. 4. Some of the field studies used to evaluate AERMOD model performance involved ambient sampling of S02 for a period of one year or more at several (typically about 1 0) monitors sited around operating power plants. Other field studies involved sampling of controlled releases of non-reactive tracers, typically SF6, generally over a shorter duration than the operational studies, but with more robust sampling to facilitate more detailed diagnosis of model performance. Although the long-term field studies associated with operating power plants included assessments of 3-hour, 24-hour and even annual average impacts from the model, evaluation re sults for 1-hour averages were routinely included for all of the field studies. As shown in Tables 2 and 3 of EPA 2003 , modeling and monitored results for 1- hour averages are in excellent correlation in the se studies, with the ratio ofpredicted to observed performance approaching 1: 1 in most instances. Thus, in my opinion , the per formance of the AERMOD model for estima ting 1-hour ambient concentrations is welldocumented and the form ofthe new 1-hour S02 standard raises no questions or concerns regarding the appropriateness of AERMOD. 5. The S02 NAAQS Coalition states that the revised S02 NAAQS is a "probabilistic " s tandard and asserts that this makes modeling more problematic, especially as compared to the previous " deterministic" standard. (C oalition p. 5.) The terms "probabilistic" and "deter minis tic" do not have an ordinarily understood meaning in this context, but it appears that the assertion is t hat predictive models like AERMOD are not suitable for a standard which includes a percentile-based form (where the relevant comparison is to a percentile of air quality from an air quality distribution), a s opposed to an expected exceedance form

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### Case: 10-1252 Document: 1288492 Filed: 01/18/2011 Page: 5 (whereby a standard may exceeded on a given number ofdays and compliance is assessed based on air quality on the designated day once the allowed exceedance days are removed from the distribution) . I know ofno reason that AERMOD and other similar types ofmodels is suitable for one type of form and not the other. As just stated in paragraph 2, the models readily generate air quality distributions from which either percentiles (for the revised S02 NAAQS, the 99 1h percentile) or exceeding days can be determined. In fact, the percentile form of the 1-hour S02 NAAQS is a more "stab le" metric than a standard based on the 151

- highest or 2"d

-highest concentrations , since the potential impact of "outliers" in the distribution is mitigated, especially when the multi-year average aspect of the S02 NAAQS is accounted for. 6. Both the S02 NAAQS Coalition and their affiant Mr. Paine raise a number ofpoints
regarding the issue of whether allowable or actual source emissions should be modeled, stating that use of allowable emissions overstates sources' impacts. See, e.g. Paine Decl. at 1[

11-14. This issue is independent of the predictive accuracy of AERMOD or other models. 7. EPA's rules and guidance provide significant flexibility in the choice ofwhich models to use in determining if sources cause of contribute to NAAQS violations for purposes ofPSD permitting. EPA's rules specify that "where an air quality model specified in Appendix W of this part .. . is inappropriate, the model may be modified or another model substituted" with written approval from EPA . 40 C .F .R. §51. 166 (1)(2). The rules therefore allow flexibility , subject to appropriate requirements, for alternative modeling techniques to be applied on a case-by-case basis subject to appro val by appropriate reviewing authority. 8. The declaration of Michael E. Long voices concerns regarding the use ofthe AERMOD dispersion model to support implementation of the 1-hour S02 standard , and asserts that

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### Case: 10-1252 Document: 1288492 Filed: 01/18/2011 Page: 6
"AERMOD significantly over predicts the actual one-hour ambient concentrations in our area when the available information is used in the model as directed by EPA." Long Decl. at

8. This assertion is based on a comparison bf model -predicted ambient concentrations to amb ient 

### 802 concentrations reported for 2008 at local EPA monitoring stations in the vicinity ofthe ArcelorMittal facilities being modeled. Mr. Long reports that the "AERMOD model predicted one-hour concentrations that were higher than the monitored values 90% of the time and the predicted values were as much as 373,131 times higher than the actual monitored values." I d. Lacking any additional details re ga rding the model-to

-monitor comparisons cited by Mr. Long, the response here is necessarily limited to a general discuss ion of issues involved in such comparisons. A number of factors can affect the comparison of a modeled concentration with a monitored concentration, including the accuracy of the emission rate and other source characteristics input to the model, the representativeness of the meteorological data input to the model, and the influence of local geographical features and land us e characteristics on the transport and dispersion of the plume. Another key factor that affects comparisons of modeled vs. monitored concentrations, paired in time and space, i s the potential error or uncertainty in the wind direction input to the model for that hour since the wind direction w ill determine the transport direction of the plume
. Slight errors in the trans port wind direction may account for significant dif ferences in modeled vs. monitored concentrations for a specific hour, especially for elevated plumes under stable atmospheric conditions where the lateral spread of the plume can be very limi ted for relatively long transport di s tances, and errors ofa few degrees in wind direction can be the difference in the plume directly impacting the monitor for a particular hour or the plume missing the monitor completely. In such cases, a factor of

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### Case: 10-1252 Document: 1288492 Filed: 01/18/2011 Page: 7
373,131 differen ce between modeled and monitored concent rations could easily be attributable to error or uncertainty in the wind direction
. Note that wind d irections reported from routine meteorological monitoring stations located at airports, the most common source of meteorological data used in air quality modeling applications, are reported to the nearest 10 degrees. In addition, the comparison may reflect issues related to use of all owable versus actual emi ssions, which is irrelevant for purposes of determining whether the AERMOD model itself is biased. 9 . The declaration of Robert J . Paine addresses practical issues in applying the AERMOD model that allegedly arise due to the form ofthe 1 -hour S02 standard, as well as concerns regarding the conservatism of the assumptions on source emissions based on Appendix W guidance in relation to the 1-hour S02 standard. Responses to these issues are summar ized below, numbered according to Mr. Paine's declaration, with some responses applying to multiple comments: (a) Paine Decl. 9. : The AERMOD model "does not yet provide results that allow permit applicants to follow EPA ' s guidance for determining whether they comply with the 1 -hour S02 NAAQS because ofthe unique statistica l form ofthat NAAQS . " Paine Decl. 

### 11 10.: "The form ofthe 1-hour S02 NAAQS requires the applicable guideline dispersion model to compute the highest 1-hour concentration for each day at each modeled receptor point, and to keep track of this dai ly 1-hour maximum concentration s tatistic for each of the 365 days for each year modeled independently at each location modeled
.

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### Case: 10-1252 Document: 1288492 Filed: 01/18/2011 Page: 8 Paine Decl. 1 1. : " In the case for which a cumulative modeling analysis is required, this same procedure must be applied to the combined contributions ofthe individual source being permitted, nearby sources and reg ional background." Response: As stated in paragraph 2 above , all ofthese metrics are readily obtainable from model outputs . A lthough the existing version of AERMOD does not contain an algorithm f rom which these metrics emerge auto matically as model outputs , this does not change the result that all of these metrics are obtainable. In fact, we are aware that Mr . Paine, along with other private sector parties, developed po st-processing tools to compute the 1

-hour S02 design value based on the fo rm of the revised S02 NAAQS utilizing model output options available at the time. (b) Paine Decl. 

### 'II 11. : "Furthermore , EPA in most cases requires a conservatively high regional background concentration to be added for all hours modeled, rather than the actual values measured during each hour of the modeling simulation
. " Response: EPA issued guidance on a range of issues related to the new 1-hour S02 standard on August 23,2010, including a recommendation that the overall highest 1 -hour monitored S02 concentration from a representative monitor could be u sed to account for the monitored background component in a cumulative impact assessment "without further j ustification. " We recognize that use of the overall highest 1-hour monitored value may entail a degree of conservatism tha t could prevent a source from demonstrating compli ance with NAAQS; however , tha t conservatism forms the basis for allowing the approach to be used without further justification. The August 23 memorandum further stated that " Additional refinements to this 'first tier' approach based on some level of temporal pairing of modeled and monitored values
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### Case: 10-1252 Document: 1288492 Filed: 01/18/2011 Page: 9
may be considered on a case-by-case basis, subject to approval by the reviewing authority, with adequate justification and documentation." However, we also note that Appendix W explicitly makes "no attempt" to "comprehensively define" the criteria involved in determining which nearby sources to include in an analysis "owing to both the uniqueness of each modeling situation and the large number of variables involved in identifying nearby sources." See Appendix W section 8.2.3.b. (c) Paine Decl. 1! 12.: "Following EPA's regulatory requirements for PSD modeling, the modeled predictions of hourly concentrations of a probabilistic standard such as the 99th percentile daily maximum hourly S02 concentrations produced by a single source for which a permit is sought
can be much higher than concentrations that a ctually occur in the ambient air." Response: As noted in paragraph 6 above, the issue of allowable versus actual emissions is independent to the question of the accuracy of AERMOD or other models. Also , as stated in paragraph 5 aboY e, there is no reason that AERMOD (or other similar models) is not equally accurate in predicting percentile air quality distributions or expected exceedances on a given day
. The underlying data which are input to the model generate air quality di str ibutions which are equally suitable for either type of form. (d) Paine Decl. 12. : " Modeling ofpeak S02 emissions as if they occur continuously is a distortion of reality and will overestimate the ambient air concentrations. This is especially true for 1-hour averages, since the variation of emissions for such a short averaging period is

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### Case: 10-1252 Document: 1288492 Filed: 01/18/2011 Page: 10 potentially much higher than that for the other S02 NAAQS averaging periods. This makes the assumption ofconstant peak emissions a critical issue for this new standard." Response: The purpo se of dispers ion modeling in the context ofthe PSD permitting program is to demonstrate that the proposed new or modified emissions will not cause or contribute to viola tions of t he standard if the permit i s granted. This is inherently a predictive exercise since it entails an assessment ofproposed future emissions. EPA's guidance for conducting such analyses is dictated by and consistent with that purpose. Mr. Paine's statement that 1-hour averages are more variable than longer averaging periods again does not relate to potential model bias and in any case makes a sweeping generalization for situations that differ case-by-case. The statement that peak S02 emissions should not be modeled is a restatement 

### of the dispute as to
use of allowable or actual emissions, and does not relate to the issue ofmodel bias. (e) Paine Decl. , 13. : "The model overprediction tendency is even more likely to be a problem in a cumulative impact analysis because numerous sources (i.e. , the source being permitted and potentially thousands of other nearby sources) are all modeled at peak em is sions at all times and added to a regional background level of S02 ... leading to unrealistic predictions that the 1-hour S02 NAAQS will be exceeded." Response: As noted, the issue of allowable versus actual emissions is independent ofthe issue of models' predictive accuracy. However, EPA's August 23,2010 clarification memo regarding the applicability of Appendix W guidance for the 1-hour S02 NAAQS cautioned "against the literal and uncritical application of very prescriptive procedures for identifying which background sources should be included in the mode led emission inventory for NAAQS 10

### Case: 10-1252 Document: 1288492 Filed: 01/18/2011 Page: 11 compliance demonstrations, including those described in Chapter C , Section IV. C.l of the draft New Source Review Workshop Manual (EPA , 1990) , noting [again] that Appendix W emphasizes the importance ofprofessional judgment in this process." One motivation for that caution was a concern that application of such procedures could lead to an overly conservative result by including too many background sources in the cumulative impact assessment. As noted elsewhere, Section 8.2.3.b ofAppendix W suggests that "the number of such sources is expected to be small except in unusual situations. " (f) Paine Decl. 13. : "Moreover, since the nearby sourc es will be modeled individually (but their emissions are already accounted for in the regional monitoring), there will inevitably be doublecounting ofthe background impacts between the components ofthe "nearby sources " and the "regional background", especially for the common situation of the state requiring a single peak regional background value to be used for all modeled hours. " Response: As noted in several responses above, there are many application-specific factors that need to be considered in determining how to conduct an adequate assessment of cumulative impacts , accounting for contributions from nearb y backgroun-d sources explicitly in the model as well as a monitored contribution , while avoiding or minimizing the potential for double-counting of modeled and monitored impacts. (g) Paine Decl. 14. : "The distribution of total peak daily emissions over the three-yea r period of 2000-2002 [from major S02 sources in central North Dakota] was found to overpredict the second-highest monitored 24-hour concentrations by roughly a factor of2 because the emissions 11

### Case: 10-1252 Document: 1288492 Filed: 01/18/2011 Page: 12

on average are lower than peak values assumed in the modeling
. For t he probabilistic 1

-hour standard
. . . and for closer receptors , the overprediction ratio would likely be even higher than for a 24

-hour average, causing extens ive areas of fictitious modeled NAAQS violations
. " Response: The first statement in this comment merely confirms what was indicated in an earlier response, namely that modeled impacts based on maximum allowable emissions should not be expected to accurately predict ambient monitored concentrations in most cases, since monitored concentrations can only reflect impacts from actual emissions. Overprediction by a factor of 2 does not suggest a significant degree of conservatism given that modeled emissions reflected peak emissions. No rationale is offered to support the assertion that the overprediction ratio would likely be even higher for the 1-hour standard, and we see no reason to expect that necessarily to be the case. (h) Paine Decl., 14. : "Based on my experience with modeling the 1-hou r NAAQS for nitrogen dioxide

- a NAAQS that is
. similar in form to the 1-hour S02 NAAQS

- this overprediction ratio could approach a factor of 10 in areas with numerous sources modeled together." Response: Although the form of the 1-hour N02 standard is very similar to the form ofthe 1- hour S02 standard, the ro le ofNOx chemist ry in modeling ambient N02 impacts associated with NOx emissions makes 

### it difficult to draw comparisons between the two standards in terms ofthe potential for the model to overestimate ambient impacts as compared to monitored concentrations. The comment does not indicate what assumptions were made in the N02 modeling analyses regarding the conversion ofNO emissions to ambient N02. An overly conservative assumption in relation to that conversion could introduce a significant bias in the 12

### Case: 10-1252 Document: 1288492 Filed: 01/18/2011 Page: 13 modeled concentrations relative to monitored concentrations ofN02 that would have no relevance to modeling 1-hour 802 impacts. (i) Paine Decl. 15. : "If a cumulative modeling assessment shows violations of the NAAQS, then the PSD permit applicant can still obtain a permit for its source by s howing that the proposed
source does not contribute significantly to the modeled viol ation
. EPA, however, has not yet defined a procedure for determining whether a proposed source that conducts a cumulative modeling analysis and finds modeled violations due to other sources is by itself causing or contributing to these predicted (and possibly false) 1-hour 802 NAAQS violations. This "safety valve" thus does not yet exist for applicants trying to demonstrate that their proposed 802- emitting sources will not cause or contribute to any modeled violations of the
. l -hour 802 NAAQS." Response: Recognizing the importance ofthe significant contribution test within the PSD permitting program, EPA recommended an interim Significant Impact Level (SIL) in its August 23 guidance memorandum regarding the 1-hour 802 NAAQS. This interim SIL provides the "s afety valve" that may allow a permit applicant to obtain a permit in cases where the cumulative impact assessment shows modeled violations of the 1-hour 802 NAAQ8 , if it can be demonstrated that the proposed emis sion increases do not contribute significantly to those modeled violations, paired in time and space. Although the form of the 1-hour 802 standard may complicate the "bookkeeping " needed to make such a demonstration, the principle of the significant contribution tes t based on the SIL has not changed under the 1-hour 802 NAAQS.

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### Case: 10-1252 Document: 1288492 Filed: 01/18/2011 Page: 14
Pursuant to 28 U.S.C. § 1746, and under penalty of perjury, I declare the foregoing is true and correct to the best of my knowledge.

Date Roger W. Brode

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