AECOM 978.589.3000 tel 2 Technology Park Drive 978.589.3100 fax Westford, MA 01886-3140


# Memorandum

To enhance and sustain the world’s built, natural and social environments To: Scott Bohning Page 1
cc: Shirley Rive ra, Sara Head Subject: Response to EPA Additional Comments on AECOM 1-hour NO 2 NAAQS A nalysis for Palmdale Hybrid Power Project From: Richard Hamel Date: December 14, 2010


### I. Background On April 1, 2009, AECOM, on behalf of the City of Palmdale, submitted a Pr evention of Significant Deterioration (PSD) permit application to EPA R egion 9 for the Palmdale Hybrid Power Project (PHPP). A conference call between EPA and PHPP representatives was hel d in March 2010, during which supplemental information was requested by EPA on several items, including the PM2.5, visibility, BACT and other analyses , as well as the analysis with respect to the 1-hour NO 2 National Ambient Air Quality Standard (NAAQ S) that became effective in April 2010. On July 21, 2010, AECOM submitted the "Palmdale Hybrid Power Proj ect (PHPP) - Supplemental Information for the Application for PSD Permit" in res ponse to that conference call. On August 26, 2010, EPA (Scott Bohning) prov ided comments via email on the supplemental analyses, focusing on the supplemental 1-hour NO 2 NAAQS analysis. In response, AECOM provided a memo on October 7, 2010 and then discussed thes e responses with Mr. Bohning on October 25, 2010. Subsequently, Mr. Bohning participated in a conference ca ll on October 27, 2010 with EPA’s Office of Air Quality Planning and Standards (OAQPS) regarding the 1-hour NO 2 NAAQS analysis for PHPP and other PSD projects under review by EPA . Mr. Bohning then provided additional comments via email on October 28, 2010 which incorporated the OAQPS guidance for the various 1-hour NO 2 modeling issues, as well as recommendations specific to the PHPP. This memo addresses most of EPA’s outstanding comments regarding the PHPP 1-hour NO 2 cumulative modeling analysis (provided via Mr. Bohning’s email on October 28, 2010), resolution on each is desired before re vised modeling can be s ubmitted. For organizational purposes, each EPA comment contains Mr. Bohning’ s paraphrasing of the OAQPS guidance followed by EPA’s PHPPspecific recommendation (as prov ided in EPA’s email). The App licant’s response follows each EPA comment. To facilitate EPA’s review, figures and modeling files which suppor t the responses to the various comments are attached.AECOM 2



### II. Responses to October 28, 2010 Comments Following are responses to five of EPA’s 6 comments in the October 28 th email. The 6 th comment is related to the application of the hourly time matched NO 2 background values. As shown in the response to comment #2 (Table 2), there is not a strong seasonal relationship to the background concentrations, and the diurnal dist ribution is strongly tied to the commute/train schedule. Other than the commute hours, the background concentrations are the lowest in the Summer, which would be the main time of the year that the PHPP will operate, as this is the time with peak power demand. However, since the power plant could operate during any mont h, AECOM investigated other approaches but was unable to discern an obvious alte rnative on which to base a different averaging technique that could be easily applied. Use of maximum monthly or seasonal values, which were still dominated by the highly traffic influenced monito r concentrations during commute hours, did not provide any benefit to this analys is. Therefore, we request further feedback from EPA on what approaches would be acceptable and reasonable for this Project. Upon further direction and/or reso lution of these issues, AECOM will provide a revised modeling analysis. 1. IN-STACK NO2/NOX RATIOS EPA Comment: Should not just cite conversation with equipment vendor on ratios; provide information and/or data that the ratio conclusion is based on. Should not just cite line of a table provided by e.g. a local District; provide documentation of data it is based on, argument for similarity of tested source equipment to project being modeled. Note that the importance of the in-stack ratio varies by situation. For a short stack having peak NO2 impact at fence line at night, with limite d mixing and low O3, there will be limited NO to NO2 conversion beyond what is in the stack, so the in-stack ratio will be crucial, and can determine the overall answer; stronger justificat ion needed for a low ratio. For a taller stack with good mixing and higher O3, ratio is less important (and conversely, for PVMRM the equilibrium ratio will be more important). A pplicant should assess where a particular project lies between these two extremes, consider how this will affect the argument for the ratio's adequacy. PALMDALE RECOMMENDATION: Please supply any available documentation, such as stack test data, substantiating the in-stack ratios from vendor GE. Given characteristics of the source and the conditions under which high im pacts occur, as mentioned above, assess how this affects the adequacy of the ratio used. Applicant Response : In response to EPA’s August 26, 2010 comments, AECOM asked GE to provide stack test data or other information regarding GE’s input that the in-sta ck ratio for GE turbines with SCR installed would be expected to be well under 10%. After an initial response that was reported in our October 7 th memo, GE (Mr. Andrew Dicke) provided a more formal response on October 10, 2010 (a few days after our October 7 th submittal) which we have provided below:

Response to EPA Comments on AECOM 1-hour NO 2 NAAQS Analysis for PHPPAECOM 3



### Richard, In response to your enquiry regarding the ratio of NO 2 

### to total NOx contained in gas turbine exhaust GE provides the following guidance. This guidance is based on a review of available NO 2 

### emission data for 7FA gas turb ine firing natural gas fuel. GE's recommended guidance is to assume that a 7FA Gas Turbine firing natural gas will emit less than 9 ppm total NOx and NO 2 

### will constitute 10 to 15% of the total NOx emissions. If an SCR is installed downstream of the gas turbine, the anticipated NO 2 

### emission values will constitute a very small ratio of the remaining NOx, GE recommends assuming NO 2 

### is less than 5% of total NOx. The NOx ratio is expected to be below this percentage; however, GE recommends 5% due to measurement capability and variability in stack measurement results. If a CO catalyst is installed upstream of the SCR, the results can be influenced by the catalyst configuration, however the NO 2 

### ratio is consistent with the 5% value. I trust this guidance addresses your requiremen ts. Should you have any further questions or comments please do not hesitate to contact me. Regards, Andy Andrew Dicke GE Power and Water HDGT Environmental Product Marketing Manager T 518-385-0761 D *235-0761 C 518-698-9807 In light of EPA’s October 28, 2010 comments, AE COM has attempted to c ontact Mr. Dicke (via several emails and phone messages over the last fe w weeks) but has so far been unsuccessful in obtaining further information from him. As noted in the OAQPS discussion, EPA allows that the situation in whic h the data are applied can affect the importance placed on the in-stack ratio. The area where the proposed PHPP will be built is classified non-attainment for the 8-hour ozone standard. As such, the ambient background concentrations of oz one monitored at the Lancaste r Division Street monitor are generally high. In situations with a high background concentra tion of ozone, the in-stack ratio of NO X to NO 2 is of limited importance because of the large amou nt of ozone available for post-sta ck conversion. Therefore, the choice of in-stack ratio for the co mbustion turbines at PHPP is expect ed to not be a factor in the PHPP 1-hour NO 2 NAAQS modeling demonstration. Given that the in-stack ratio is not critical in this situation and since GE indicates the actual ratio with an SCR should be well less than 10%, AECOM feels that a ratio of 10% or less is justified in this application.

Response to EPA Comments on AECOM 1-hour NO 2 NAAQS Analysis for PHPPAECOM 4

2. NO2 AND O3 BACKGROUND MONITORS EPA Comment: OK to show NO2 conservativeness based on monitor proximity to roadways, and monitor inclusion of some impacts from n earby sources. Should be quantitative where possible, e.g. compare monitor and project site on their distan ces from nearby point sources, roadways, amount of vehicle traffic. In general, choice of background cannot be determin ed in isolation; it depends on how it is added to model, and on what conditions that background represents. (What background sources does it capture under various conditions?) Consider what is upwind of monitor and of project. Background concentration can vary by direct ion (and by meteorological condition...) Project and monitor similar distance to urban area may add to argument for representativeness. PALMDALE RECOMMENDATION: The documentation supplied about the representativeness/conservativeness of the Lan caster Division Street NO2 monitor is very useful, but it should be supplemented with a co mparison to the features of the project site, such as distance to nearby point sources, ro adways and the amount of traffic on them. Applicant Response : Our response provides additional deta il related to point, line and area sources near the PHPP and the monitor. To aid the discu ssion, wind roses from the Palmdale Regional Airport/USAF Plant 42 are provided in Attachment A for the years 2000 – 2006. As can be seen in the wind roses, “downwind” will typically re flect sources in the southwest quadrant. The primary non-Project point sour ces contributing to the backgro und at the PHPP site are the Lockheed-Martin and Northrop-Grumman facilities loca ted on U.S. Air Force (USAF) Plant 42 property adjacent to the PHPP. Emissions from sources at these two facilitie s were included in the cumulative NO 2 modeling. Since these sources are located ab out 4 km from the Lancas ter monitoring station, they will also contribute to the ambient background, hence when usi ng a background value that is not matched to the meteorological conditions will lead to some “double counti ng”. There are no other major point sources of NO 2 near (within 6 miles [10 km]) the PH PP (or the monitor) beyond those that are explicitly included in the mode ling (see response to comment #5). The primary line sources in the area, as described in the supplemental 1-hour NO 2 submittal of October 7 th , are the Metrolink rail line, the Sierra Hi ghway, the Antelope Valley Freeway (SR-14), and commute related traffic on Division Street. The lo cations of these line sources with respect to PHPP and the monitor are shown in Figure 1. Table 1 shows the distance betw een these line sources and the Project as compared to the monitor. The maximum modeled impacts for normal operations, as well as st artup / shutdown, occur on the eastern fence line of the PHPP. The distance from the line sources to the location of the maximum impacts would thus be slightly hi gher than the “Distance from PHPP” in Table 1 below. As can be seen in the table, the monitor is much clos er to all of the local line sources of NO 2 emissions than the

Response to EPA Comments on AECOM 1-hour NO 2 NAAQS Analysis for PHPPAECOM 5

Project and location of the maximum impacts. More importantly, these sources are generally northsouth roadways and rail line that would be upwind of both the monitor and PHPP (at different points along the line) during the meteorological conditions t hat lead to the maximum impact, so the distance is particularly relevant. The east-west streets present near PHPP also have significantly less traffic than those near the monitor. East Avenue M, an east-we st road that defines the nort hern boundary of the PHPP site, experiences traffic volumes of around 18,500 vehicles / day in the vicini ty of the Project according to the City of Lancaster Tr affic Engineering Division 1 . Due to the extensive area covered by USAF Plant 42, there are no east-west streets within 4 km south (upwind) of the PHPP power block that would have substantial traffic volumes (t he closest is Avenue P/Rancho Vista Blvd.) The traffic volumes of the east-west streets near the monitor however are significantly higher: Avenue K experiences traffic volumes of approximately 25,000 vehicles / day to the east of the monitor, and over 30,000 vehicles / day to the west. Avenue L experiences daily volume s well in excess of 30,000 vehicles / day to the southwest of the monitor, directly upwind of the monitor in the predom inant wind direction. There are also other streets (Avenue K6 and K8) that r un east-west near and downw ind of the monitor. Table 1: Distance from Project Power Block a nd Lancaster Monitor From Local Sources of NO 2 Emission Source Distance From Monitor Distance From PHPP Daily Volume (vehicles/day) Sierra Highway 110 meters ~2 km 20,000+ Southern Pacific Rail 80 meters ~2 km 24 trains / weekday 6-12 trains on weekends Antelope Valley Freeway 1 Just over 2 km Just over 4 km ~80,000 at Ave. L exit Division Street 2 50 meters About 3 km ~18,000 near the monitor Avenue K 0.6 km ~4.0 km 30,000 / 25,000 to the west / east of monitor Avenue L ~1.0 – 1.5 km ~3.5 km 30,000+ west of monitor Avenue M ~2.5 – 3.0 km 0.5 km 18,500 in vicinity of PHPP 1. http://www.laalmanac.com/transport/tr26b.htm#14 2. This portion of Division Street ends at E Avenue L and starts again in Palmdale west of Sierra Highway Additionally, the monitor is significant ly affected by commute traffic idli ng at the intersection in front of the building where the monitor is cited, as described by Mr. Chris Anderson in the October 7 th submittal. This scenario is borne out in reviewi ng the distribution of the background data by hour and season, as shown in Table 2 bel ow. As seen in the table, t he 8 hours with the highest maximum recorded background combination occur from 5 am to 9 am, and 5 pm to 8 pm, corresponding closely to the daily commute, and the time at which the Metrolink commuter trains begin running from Lancaster to Los Angeles each morn ing (commencing at 3:58 am, t hen 4 more trains between 5 am

1 http://www.cityoflancasterca.org/Modu les/ShowDocument.asp x?documentid=4370 Response to EPA Comments on AECOM 1-hour NO 2 NAAQS Analysis for PHPPAECOM 6

and 7 am) 2 . Because this congestion does not occur at the Project site, the background values recorded during these hours, which constitute 33% of the total background data collected, significantly overstate the ambient background conc entration at the Project location. Because of the much closer proximity of the vehi cle and rail traffic sources to the monitor during the wind conditions that produced t he highest modeled impacts, it can be assumed that the background concentrations during these periods are conservative compared to those occurring near the Project site during the worst case modeling scenario. Table 2: Maximum Ambient Concentration by Hour and Season (ppb)
Time Winter Spring Summer Fall Overall 0:00 41 45 27 43 45 1:00 41 38 24 39 41 2:00 40 41 24 35 41 3:00 39 43 42 40 43 4:00 40 47 49 49 49 5:00 44 61 65 62 65 6:00 50 56 61 64 64 7:00 51 55 49 60 60 8:00 56 50 34 56 56 9:00 50 46 24 50 50 10:00 40 20 18 39 40 11:00 40 16 10 28 40 12:00 25 18 18 24 25 13:00 25 18 13 23 25 14:00 25 18 13 25 25 15:00 38 18 15 35 38 16:00 40 20 14 40 40 17:00 50 30 15 62 62 18:00 48 49 17 56 56 19:00 52 43 24 50 52 20:00 48 58 33 49 58 21:00 45 47 30 47 47 22:00 51 45 40 43 51 23:00 1 29 4 ND ND 29 1. Most of the data from the hour beginning at 23:00 is missing from the dataset as the monitor is re calibrated nightly at that time.

2 http://www.metrolinktrains.com/schedules/pdf.php?id=1041 Response to EPA Comments on AECOM 1-hour NO 2 NAAQS Analysis for PHPPAECOM 7

The only potentially signifi cant area source of NO 2 emissions closer to the Project site than the monitor is air traffic at the Palmdale Regional Airport/USAF Plant 42. The airport is operated by Los Angeles World Airports (LAWA), but air traffic at th e airport is minimal since no commercial airlines currently operate there. In a 1989 agreement with the Air Force, commercial traffic is currently allowed up to 50 operations per day, with an operation being either a landing or a takeoff 3 . Eight airlines have attempted to estab lish a viable business at Palmdale R egional Airport since 1971, all of which have failed. In 2009, includi ng military operations, there were an annual total of 26,905 landing or take-off operations, an average of 73.7 operations per day 4 . In 2007 and 2008, the average operations per day were 92.4 and 80. 2. Because the runways are lo cated to the south and southeast of the PHPP, these emissions should not impact the receptors showing the maximum modeled impacts at the same time as PHPP sources, which occur when the winds are blowing from the west. Any long term contributions to the ambient background concentr ation should be picked up by the Lancaster Division Street monitor, less than 4 kilometers away. No other significant sources of NO 2 exist upwind of the highest modeled impacts that would contribute significantly to the modeled concentrations. No other monitors that collect NO 2 data in the region were found t hat could be expected to be a better fit than the location selected. The nearest monitor other than the Lancaster Divi sion Street monitor is located in Santa Clarita, nearly 50 kilometers from the Project site, and located in a mountain setting dissimilar to that of Lancaster / Palmdale. Based on the discussion above along with the detailed information abo ut the sources local to the monitor given in the 1-hour NO 2 cumulative analysis, AECOM believe s the Lancaster Division Street Monitor conservatively reflects the ambient background in the vicinity of the PHPP because:

• Close proximity of the monito r to the Project site (4 km)

• Closer proximity to the monitor of the Ante lope Valley Freeway, Sierra Highway, Metrolink rail line, and major streets which are loca ted upwind of the monitor and PHPP when the highest modeled impacts occur.

• The fact that the emissions from Lockheed Martin and Northrop Grumman are included in the modeling inventory, as well as contribute to the ambient background concentration, and are thus double counted in the modeled impacts.

• Background values for commute hours are likel y overstated for the Project location by 30- 50%. 3. MISSING O3 DATA PROCEDURE EPA Comment: Not appropriate to use an annual aver age to fill in missing hourly ozone values: misses high values that can occur during the day. Using the higher of the missing interval endpoints is more conservative than interpolation, but for longer intervals may miss an ozone peak. Even if it is OK for a particular data set, it's not a good general rule to approve. Better to start wi th an approach guaranteed to be conservative,

3 http://www.jpbroker.com/pairport.html 4 http://www.city-data.com/airports/Palmdale-Regional -Usaf-Plant-42-Airport-Palmdale-California.html#PMD Response to EPA Comments on AECOM 1-hour NO 2 NAAQS Analysis for PHPPAECOM 8

then make special case arguments for problematic hours. (Instead of starting with a usuallyconservative approach and then arguing that it's probably OK.) Example approach: for each of the 24 hours of th e day, use maximum value that occurs for that hour (24 separate default values); or do th is for each month (288 sep arate default values). Requires a bunch of post-processing. PALMDALE RECOMMENDATION: It would be preferable to start with a conservative approach, such as substitution of a value from the co rresponding seasonal or monthly high hour (as mentioned in the example). Professional judgmen t could then be applied to problematic hours, using an alternative approach that continues to insure that no underprediction bias is introduced. However, the approach proposed during our 10/25 phone call, using interval endpoint highs for intervals longer than 3 hours would still be acceptable for this particular data set, if it is one part of an overall substitution procedure, and is accompanied by a documented assessment of the reasonableness of substitutions of 3 or more consecutive daytime hours in comparison with neighboring days. Applicant Response : AECOM proposes the following ozone filli ng strategy, which incorporates the EPA recommendation above:

• Where there is 1 or 2 hours missing, the hi gher of the two endpoints will be persisted across the missing hours.

• Where 3 or more hours are missing, the higher of the following will be persisted across all hours in the missing period: o The higher of the two endpoints, or; o The highest value from any hour in the miss ing period from the day before or after the day where the missing hours occurred. 4. USE OF 3 YEARS RATHER THAN 5 YEARS OF METEOROLOGICAL DATA EPA Comment: As discussed in the "Applicability of Appendix W Modeling Guidance for the 1- hour NO2 NAAQS", memorandum from Tyler Fox, 2010-06-28, as well as in Guideline on Air Quality Models §8.3.1.2, five years of representati ve meteorological data (or one year of on-site data), are required in air quality impact analyses. However, the modeling supplied for NO2 as well as for the other pollutants evaluated used only three years of data. While three years of data may have been accepted for past applications by other permitting authorities, or even by EPA in particular circumstances, we do not beli eve that is a sufficient rationale for using less than the 5 years specified in EPA's regulatory guidance. Additional justification would be required for using a shorter data set. Applicant Response : The Application for Prevention of Significant Deterioration Permit for the Palmdale Hybrid Power Project was submitted on Ap ril 1, 2009. Prior to that application, the “ Class II Area Dispersion Modeling Protocol for the Proposed Palmdale Hybrid Power Project” was submitted to EPA on August 6 th , 2008. The modeling protocol fully described the process by which the meteorological data to be used in the modeling were selected and processed for use in the analysis, which includes 3 years of data from 2002-2004. Sinc e that time, a total of 4 modeling analyses, between the original modeling and supplemental m odeling submitted in response to EPA Region 9

Response to EPA Comments on AECOM 1-hour NO 2 NAAQS Analysis for PHPPAECOM 9

comments, have been presented to EPA region 9, wi th no comments whatsoever about the use of 3 years of data for the PSD permitting of this Project. EPA Region 9 has had many opportunities to comment on the appropriateness of the meteorological data for almost four years and related to two projects 5 , one of which was fully approved, and has never indicated t hat there was any issue with regard to the selection of meteorological data for PHPP. It was our understanding that these data were accept able, not only due to the lack of comments to the contrary, but because the data used for PHPP can be cons idered to be “on-site” data , in which case only one year is required. For the PHPP modeling analysis, the meteorological data chosen was collected at the Palmdale Regional Airport, which is located on the property of United States Air Force Plant 42. The relative locations of the PHPP power block and the meteorological tower is shown in Figure 2. The tower is located less than 2.5 kilometers from the power block and meets the description outlined for “Site Specific” as defined in section 8.3.3 of the EPA Guideline on Ai r Quality Models (GAQM; as incorporated in Appendix W of 40 CFR Part 51; EPA , 2005). Both the PHPP stack locations and the meteorological tower are very close to the Palm dale Regional Airport runways and are physically located in wide open space. The tower is in direct line of sight with the PHPP stacks, and due to its location on USAF Plant 42 property, will experience near ly identical meteorological conditions in terms of wind speed/direction, temperatures, humidity, pressure, prec ipitation, etc., at all times. As an additional step towards confir ming that the met tower should be considered site specific, the land use characteristics of both the PHPP power block and the tower were calculated with the AERSURFACE pre-processor for AERMOD and com pared. The source parameters used for both runs were identical to those described in the “ Class II Area Dispersion M odeling Protocol for the Proposed Palmdale Hybrid Power Project”, except that to make an equivalent comparison between the two sites, twelve 30 degree sectors were used for both:

• Twelve 30 degree land-use sectors

• Annual results by sector were compared

• 1 kilometer radius

• At airport = ‘Y”, Arid location = “Y ”, One month of snow cover = “N”.

• Seasons defined as follows:
o Jan, Feb: Late autumn after frost and harvest, or winter with no snow.
o Mar, Apr, Nov, Dec: Autumn with unharvested cropland.
o May, Jun, Jul, Aug, Sep, Oct: Midsummer with lush vegetation

5 The Application for PSD Permit for the Victorville 2 (VV2) Hybrid Power Project, a virtual clone of PHPP proposed for construction in the same region as PHPP (less than 50 miles away), was done in a similar fashion. The Class II modeling protocol was submitted to EPA Region 9 on January 17, 2007, followed by the PSD application on May 3 rd
, 2007. The modeling analyses for that project also used 3 years of data from 2002-2004 from a nearby met tower. Over the course of that project there were num erous submittals to EPA Region 9. On March 11 th , 2010, EPA Region 9 granted the PSD Permit for VV2. At no time during the permi tting process did EPA Region 9 ever question the use of 3 years of meteorological data in the PSD modeling, though at one point the agency did ask for further information on how the missing data was filled, so the me teorological data were reviewed by EPA.

Response to EPA Comments on AECOM 1-hour NO 2 NAAQS Analysis for PHPPAECOM 10

The results of the AERSURFACE runs are shown in Table 3. The table shows that the surface characteristics of the two locations are virtually identical from every wind direction, with a maximum difference in surface roughness of 0.03 m (3 c entimeters) and an average difference of less than one centimeter. With such small differences, the surf ace roughness at the tower and the Project site are effectively identical. The AERSURFACE modeling file s are attached to this memo in zipped format. Table 3: Comparison of Surface Roughness at PHPP Stack Locations and Palmdale Regional Airport Meteorological Tower (m)

Sector Airport PHPP Difference 1 0.128 0.133

‐ 0.005 2 0.122 0.125

‐ 0.003 3 0.131 0.126 0.005 4 0.127 0.123 0.004 5 0.123 0.129

‐ 0.006 6 0.121 0.138

‐ 0.017 7 0.113 0.144

‐ 0.031 8 0.123 0.144

‐ 0.021 9 0.137 0.137 0.000 10 0.132 0.139

‐ 0.007 11 0.127 0.140

‐ 0.013 12 0.120 0.139

‐ 0.019 Average 0.125 0.135

‐ 0.009
Therefore, because of the close proximity of the tower to t he Project, the nearly identical characteristics of the tower and Pr oject emissions source locations, and the fact that the tower and Project site within direct line of sight of each other, the tower qualifies as site specific per Appendix W. Such has been the determination in similar situations, one of which is the Baldwin Power Plant study 6 which was used as an evaluation dat abase for AERMOD. In that case, the tower was located off property, 2.2 kilometers from the power plant stacks and was still consi dered “site-specific” for purposes of meteorological data requirements. In the case of PHPP and the Palmdale Regional Airport, the land-use at the tower and that at the Project site are, in fact, much more similar than was the case in the Baldwin Power Plant study. The reason that the years 2002 – 2004 were selected is that there was too much missing upper air data (collected at Mercury, NV) in t he later years. If 5 years of data were to be required, the dataset would need to be 2000 – 2004. Wind roses for the select ed three year period, as well as the two years before and the two years after, are provided in Atta chment A. Review of these wind roses shows that there is very little year to year variation at this site. Therefore, a requirement to redo all of the modeling (not just the 1-hour NO 2 NAAQS analysis) and other analyses for PHPP would be

6 http://www.epa.gov/ttn/scram/7 thconf/aermod/ baldwin.zip Response to EPA Comments on AECOM 1-hour NO 2 NAAQS Analysis for PHPPAECOM 11

burdensome and unjustified at this stage given that the conclusions from the modeling results are unlikely to change. Because the meteorological data from Palmdale Regional Airport meets the criteria to be considered site specific data, only on e year of meteorological data is require d for this analysis, in which case the use of three years of data meet s and exceeds the meteorological dat a requirements for this modeling analysis. 5. CRITERIA FOR CUMULATIVE SOURCE INVENTORY SELECTION EPA Comment: The October 7th AECOM memo cites Chris Anderson of the Antelope Valley Air Quality Management District (AVAQMD) as th e source of information about nearby sources to use in a cumulative modeling assessment. Ho wever, there should be documentation of the selection criteria were used, and whether they meet the requirements in the Guideline on Air Quality Models §8.2.3 on background con centrations in multi-source areas. Applicant Response : Mr. Chris Anderson, Air Quality Engi neer, and Mr. Alan De Salvio, Supervisor of Air Quality Engineering, of AVAQMD provided the following response to our request for the criteria used for cumulative source inventory selection: 

### Selection Criteria for Nearby Sources The AVAQMD selected, based upon conforma nce with the Guideline on Air Quality Models, Lockheed Martin Corporation-Palm dale and Northrop Grumman CorporationPalmdale to be included as “nearby sources”. Both are major sour ces of ozone precursors and are in very close proximity to the site. One would expect that based on these criteria both these facilities could be expected to cause a significant concentration gradient in the vicinity (6 mile radius) of th e PHPP. Minor facilities located within the 6 mile radius are expected to be included in the backgr ound monitored at the AVAQMD air monitoring station which is located in close proximity (approximately within 2 miles) of the PHPP site. Please feel free to call Rich Hamel at 978-589-3275 or Sara Head at 805-388-3775 if you have any questions or comments regarding this information.

Response to EPA Comments on AECOM 1-hour NO 2 NAAQS Analysis for PHPPAECOM 12



### Figure 1: Relative Location of the PHPP Power Block, Lancaster Monitor, and Significant Background Sources

Response to EPA Comments on AECOM 1-hour NO 2 NAAQS Analysis for PHPPAECOM

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### Figure 2: Relative Locat ion of the PHPP Stacks and Meteorological Tower

# Attachment A:

2000-2006 Wind Roses for Palmdale Regional Airport, Palmdale, CaliforniaWRPLOT View - Lakes Environmental Software

WIND ROSE PLOT: Palmdale Regional Airport 3-year 2002-2004 Wind Ros e Palmdale, CA

COMMENTS: COMPANY NAME:

MODELER:

DATE: 11/17/2010 PROJECT NO.: NORTH

SOUTH WEST EAST 4% 8% 12% 16% 20%

WIND SPEED (Knots)
>= 22 17 - 21 11 - 17 7 - 11 4 - 7 1 - 4 Calms: 10.31%

TOTAL COUNT: 25924 hrs. CALM WINDS: 10.31% DATA PERIOD: 2004 2002 2003 Jan 1 - Dec 31 00:00 - 23:00

AVG. WIND SPEED: 8.24 Knots DISPLAY: Wind Speed Direction (blowing from)WRPLOT View - Lakes Environmental Software

WIND ROSE PLOT: Palmdale Regional Airport 5 year (2000-2004) Wind R ose Palmdale, CA

COMMENTS: COMPANY NAME:

MODELER:

DATE: 11/17/2010 PROJECT NO.: NORTH

SOUTH WEST EAST 4% 8% 12% 16% 20%

WIND SPEED (Knots)
>= 22 17 - 21 11 - 17 7 - 11 4 - 7 1 - 4 Calms: 10.78%

TOTAL COUNT: 41611 hrs. CALM WINDS: 10.78% DATA PERIOD: 2001 2000 2002 2003 2004 Jan 1 - Dec 31 00:00 - 23:00

AVG. WIND SPEED: 8.37 Knots DISPLAY: Wind Speed Direction (blowing from)WRPLOT View - Lakes Environmental Software

WIND ROSE PLOT: Palmdale Regional Airport 7 year (2000-2006) Wind R ose Palmdale, CA

COMMENTS: COMPANY NAME:

MODELER:

DATE: 11/17/2010 PROJECT NO.: NORTH

SOUTH WEST EAST 4% 8% 12% 16% 20%

WIND SPEED (Knots)
>= 22 17 - 21 11 - 17 7 - 11 4 - 7 1 - 4 Calms: 12.45%

TOTAL COUNT: 58530 hrs. CALM WINDS: 12.45% DATA PERIOD: 2001 2005 2006 2000 2002 2003 2004 Jan 1 - Dec 31 00:00 - 23:00

AVG. WIND SPEED: 8.26 Knots DISPLAY: Wind Speed Direction (blowing from)WRPLOT View - Lakes Environmental Software

WIND ROSE PLOT: Palmdale Regional Airport 2000 Wind Rose Palmdale, CA

COMMENTS: COMPANY NAME:

MODELER:

DATE: 12/13/2010 PROJECT NO.: NORTH

SOUTH WEST EAST 4% 8% 12% 16% 20%

WIND SPEED (Knots)
>= 22 17 - 21 11 - 17 7 - 11 4 - 7 1 - 4 Calms: 13.11%

TOTAL COUNT: 8192 hrs. CALM WINDS: 13.11% DATA PERIOD: 2000 Jan 1 - Dec 31 00:00 - 23:00

AVG. WIND SPEED: 8.61 Knots DISPLAY: Wind Speed Direction (blowing from)WRPLOT View - Lakes Environmental Software

WIND ROSE PLOT: Palmdale Regional Airport 2001 Wind Rose Palmdale, CA

COMMENTS: COMPANY NAME:

MODELER:

DATE: 12/13/2010 PROJECT NO.: NORTH

SOUTH WEST EAST 4% 8% 12% 16% 20%

WIND SPEED (Knots)
>= 22 17 - 21 11 - 17 7 - 11 4 - 7 1 - 4 Calms: 9.86%

TOTAL COUNT: 7495 hrs. CALM WINDS: 9.86% DATA PERIOD: 2001 Jan 1 - Dec 31 00:00 - 23:00

AVG. WIND SPEED: 8.54 Knots DISPLAY: Wind Speed Direction (blowing from)WRPLOT View - Lakes Environmental Software

WIND ROSE PLOT: Palmdale Regional Airport 2002 Wind Rose Palmdale, CA

COMMENTS: COMPANY NAME:

MODELER:

DATE: 12/13/2010 PROJECT NO.: NORTH

SOUTH WEST EAST 4% 8% 12% 16% 20%

WIND SPEED (Knots)
>= 22 17 - 21 11 - 17 7 - 11 4 - 7 1 - 4 Calms: 8.57%

TOTAL COUNT: 8628 hrs. CALM WINDS: 8.57% DATA PERIOD: 2002 Jan 1 - Dec 31 00:00 - 23:00

AVG. WIND SPEED: 8.56 Knots DISPLAY: Wind Speed Direction (blowing from)WRPLOT View - Lakes Environmental Software

WIND ROSE PLOT: Palmdale Regional Airport 2003 Wind Rose Palmdale, CA

COMMENTS: COMPANY NAME:

MODELER:

DATE: 11/17/2010 PROJECT NO.: NORTH

SOUTH WEST EAST 4% 8% 12% 16% 20%

WIND SPEED (Knots)
>= 22 17 - 21 11 - 17 7 - 11 4 - 7 1 - 4 Calms: 12.24%

TOTAL COUNT: 8643 hrs. CALM WINDS: 12.24% DATA PERIOD: 2003 Jan 1 - Dec 31 00:00 - 23:00

AVG. WIND SPEED: 7.90 Knots DISPLAY: Wind Speed Direction (blowing from)WRPLOT View - Lakes Environmental Software

WIND ROSE PLOT: Palmdale Regional Airport 2004 Wind Rose Palmdale, CA

COMMENTS: COMPANY NAME:

MODELER:

DATE: 11/17/2010 PROJECT NO.: NORTH

SOUTH WEST EAST 4% 8% 12% 16% 20%

WIND SPEED (Knots)
>= 22 17 - 21 11 - 17 7 - 11 4 - 7 1 - 4 Calms: 10.12%

TOTAL COUNT: 8653 hrs. CALM WINDS: 10.12% DATA PERIOD: 2004 Jan 1 - Dec 31 00:00 - 23:00

AVG. WIND SPEED: 8.26 Knots DISPLAY: Wind Speed Direction (blowing from)WRPLOT View - Lakes Environmental Software

WIND ROSE PLOT: Palmdale Regional Airport 2005 Wind Rose Palmdale, CA

COMMENTS: COMPANY NAME:

MODELER:

DATE: 11/17/2010 PROJECT NO.: NORTH

SOUTH WEST EAST 4% 8% 12% 16% 20%

WIND SPEED (Knots)
>= 22 17 - 21 11 - 17 7 - 11 4 - 7 1 - 4 Calms: 17.07%

TOTAL COUNT: 8545 hrs. CALM WINDS: 17.07% DATA PERIOD: 2005 Jan 1 - Dec 31 00:00 - 23:00

AVG. WIND SPEED: 7.64 Knots DISPLAY: Wind Speed Direction (blowing from)WRPLOT View - Lakes Environmental Software

WIND ROSE PLOT: Palmdale Regional Airport 2006 Wind Rose Palmdale, CA

COMMENTS: COMPANY NAME:

MODELER:

DATE: 11/17/2010 PROJECT NO.: NORTH

SOUTH WEST EAST 4% 8% 12% 16% 20%

WIND SPEED (Knots)
>= 22 17 - 21 11 - 17 7 - 11 4 - 7 1 - 4 Calms: 16.03%

TOTAL COUNT: 8374 hrs. CALM WINDS: 16.03% DATA PERIOD: 2006 Jan 1 - Dec 31 00:00 - 23:00

AVG. WIND SPEED: 8.34 Knots DISPLAY: Wind Speed Direction (blowing from)