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MEMORANDUM TO THE FILE 

Subject: Revised Technical Support Document - Background Paper – Memorandum to File 

From: Ken Israels 

U.S. Environmental Protection Agency, Region 9 

Date: March 19, 2015

Figure 1 is a map of the Pechanga Band of Luiseño Mission Indians of the Pechanga Reservation 

nonattainment area (Pechanga nonattainment area). The map provides other relevant information 

including the location and design value of the air quality monitor on the Pechanga Band of Luiseño 

Mission Indians of the Pechanga Reservation’s (Pechanga’s) Indian country, county boundaries, and 

indicates EPA’s nonattainment designation. 

Figure 1
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The Pechanga Band of Luiseño Mission Indians of the Pechanga Reservation (Pechanga) is a federally 

recognized tribe whose Indian country is located primarily in the southern part of the Los Angeles-Long 

Beach-Santa Ana Metropolitan Statistical Area (MSA), with some land in the northern portion of the San 

Diego-Carlsbad-San Marcos MSA. The map below shows the location of the areas of Indian country in 

more detail. 

In 2004, EPA established the Los Angeles-South Coast Air Basin nonattainment boundaries for the 1997 

ozone NAAQS. The Los Angeles-South Coast Air Basin nonattainment area included the entirety of 

Orange County, the southwestern portion of Los Angeles County, the southwest portion of San 

Bernardino County, and the western portion of Riverside County (see Map 6 in Appendix 1 of the 2008 

8-hour ozone designation TSD). In 2004, all of Pechanga’s reservation lands were in the southwestern 

portion of Riverside County, and Pechanga’s Indian country was included in the Los Angeles-South 

Coast Air Basin nonattainment area. Since the previous designation, Pechanga has acquired lands that 

extend into San Diego County. 

From Appendix 1, Map 18 of the 2008 8-hour ozone designation TSD: For map legend describing monitors, emissions, traffic, 

population, and boundaries, see Appendix 1. 
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In June 2009, Pechanga recommended that the portions of Pechanga’s lands in Riverside and San Diego 

counties be designated as “nonattainment” for the 2008 ozone NAAQS and as a separate area, or that 

they be designated as “nonattainment” as part of the San Diego nonattainment area, for the 2008 ozone 

NAAQS (letter from Mark Macarro, Tribal Chairman, Pechanga Band of Luiseño Indians, to Deborah 

Jordan, Director, U.S. EPA Region IX Air Division, June 23, 2009). In February 2012, in response to 

EPA’s December 2011 letter conveying our preliminary designations (letter from Jared Blumenfeld, 

Regional Administrator, U.S. EPA Region IX, to Mark A. Macarro, Tribal Chairman, Pechanga Band of 

Luiseño Indians, December 9, 2011), Pechanga recommended that their reservation lands be designated 

as “nonattainment” as a separate area or as “attainment” as a separate area for the 2008 ozone NAAQS 

(letter from Mark Macarro, Tribal Chairman, Pechanga Band of Luiseño Indians, to Jared Blumenfeld, 

Regional Administrator, U.S. EPA Region IX, February 23, 2012). 

Pursuant to section 107(d) of the Clean Air Act, EPA must designate as “nonattainment” those areas that 

violate the NAAQS and those areas that contribute to violations in nearby areas. EPA evaluated the 2009 

and 2012 recommendations, including the multi-factor analysis, from the Pechanga Band of Luiseño 

Mission Indians of the Pechanga Reservation (Pechanga) based on currently available information. EPA’s 

assessment of the Tribe’s separate nonattainment area recommendation and other information was 

performed in accordance with EPA’s December 20, 2011 “Policy for Establishing Separate Air Quality 

Designations for Areas of Indian Country” (Tribal Policy)1. On April 30, 2012 EPA designated the 

Pechanga as its own NAA for the 2008 8-hour ozone standard. 

While originally included within the Los Angeles-South Coast Air Basin nonattainment area for the 1997 

ozone standard, Pechanga’s areas of Indian country are now classified differently than the rest of the South 

Coast for that standard. See 40 CFR 81.305. 

In May 2014, Pechanga submitted a redesignation request and maintenance plan for the 1997 8-hour ozone 

standard to supplement their earlier designation requests. For further discussion of this submittal, please see 

the notice of proposed rulemaking (NPRM) and our final action associated with this action. 

Table 1. Tribe’s Recommended and EPA’s 1997 8-hour Ozone NAAQS Nonattainment Designation 

Tribe-Recommended Nonattainment 

Areas of Indian country 

EPA’s Nonattainment Areas of Indian 

country 

Pechanga Reservation Pechanga Reservation

1

 The Pechanga Band of Luiseño Mission Indians of the Pechanga Reservation (Pechanga) has 

reservation lands that span across two areas designated air quality planning areas for the 1997 ozone 

NAAQS: the San Diego County, CA attainment area and the Los Angeles-South Coast Air Basin, CA 

nonattainment area. EPA is proposing to designate all of Pechanga’s Indian country as the Pechanga 

Reservation nonattainment area for the 1997 ozone NAAQS, separate from the surrounding state areas. 

Factor Assessment 

Factor 1: Air Quality Data 

 

1 http://www.epa.gov/ttn/oarpg/t1/memoranda/20120117indiancountry.pdf
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For this factor, we considered 8-hour ozone design values for air quality monitors in and near Pechanga, 

based on data from the 2011-2013 period (i.e., the 2011 design value, or DV) and preliminary data from 

the 2012-2014 period (i.e., the preliminary 2012 DV). A monitor’s DV is the metric or statistic that 

indicates whether that monitor attains a specified air quality standard. The 1997 ozone NAAQS are met 

at a monitor when the annual fourth-highest daily maximum 8-hour average concentration, averaged 

over 3 years, is 0.08 parts per million (ppm) (80 parts per billion (ppb)) or less. A DV is only valid if 

minimum data completeness criteria are met. See 40 CFR part 50 Appendix I. Where several monitors 

are located in a county (or a designated nonattainment area or maintenance area), the DV for the county 

or area is determined by the monitor with the highest level. 

Monitors that are eligible for providing design value data include monitors that are sited in accordance 

with 40 CFR Part 58, Appendix D (Section 4.1), are federal reference method (FRM) or federal 

equivalent method (FEM) monitors, and meet the requirements of 40 CFR part 58, Appendix A. 

Map 18 in Appendix 1 of the 2008 8-hour ozone TSD shows ozone monitors in, and surrounding, 

Pechanga’s areas of Indian country. Currently, Pechanga operates one ozone monitor within its 

Reservation. An issue with this monitor was identified and resolved in the summer of 2011. For a 

thorough discussion of this issue please see EPA staff memorandum to file titled “Temecula Missing 

Data Analysis for 2011-2013,” October 6, 2014 and the EPA’s “Pechanga Ozone Data Assessment,” 

August 4, 2011. EPA has analyzed the accuracy of the ozone data from this monitor and has determined 

that data collected prior to resolution of the issue cannot be used for the current ozone designations. The 

limited accurate air quality monitoring data available from the Pechanga monitor after the issue was 

resolved suggest that ozone concentrations at Pechanga are reasonably similar in magnitude and timing 

to a nearby monitor located north of Temecula. See figures 1 and 2 below. There is sufficient valid data 

from the Temecula monitor to determine that its 4th maximum 8-hour ozone value for 2011-2013 is 

0.078 ppm, which is below the level of the 1997 ozone NAAQS.2 EPA further examined the Temecula 

and Pechanga monitoring data in preparing our final action (Please see the docket item titled, 

“Maximum Daily 8-hour Ozone Concentrations for Selected Monitors 2012-2014” for the updated data 

presentation) the results of this further examination result in the design values presented in the table 2 

below.

 

2

For 2011-2013, the Temecula monitor achieved only 89 percent completeness, which is less than the required three-year 

completeness requirement of 90 percent. EPA Region IX staff conducted a missing data analysis for the Temecula station in 

accordance with the requirements of 40 CFR 50 Appendix I, Section 2.3(b). EPA evaluated the comparability of ozone 

concentrations for several surrounding ozone monitors. Monitors evaluated included Pechanga (AQS Site ID: 06-073-1008) 

and Lake Elsinore (AQS ID: 06-065-9001). Specifically, EPA examined daily 8-hour 1st maximum ozone concentrations for 

June 4, 2012 to June 20, 2012, July 1, 2012 to August 9, 2012, February 20, 2013 to March 17, 2013, and April 14, 2013 to 

April 29, 2013. EPA’s analysis showed that substituting ambient data from nearby monitors for the missing days at the 

Temecula monitor would not have caused a violation the 1997 8-hour ozone standard. See EPA staff memorandum to file 

titled “Temecula Missing Data Analysis for 2011-2013,” October 6, 2014. 
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Table 2 – Fourth Highest 8-Hour Ozone Concentrations at Temecula and Pechanga Monitors, 

2012-2014, ppm 

Monitor 

(Site code) 2012 2013 2014a 2012-2014 design value a, b

Temecula 

(06-065-0016) 0.077 0.074 0.074 0.075 

Pechanga 

(06-065-0009) 0.075 0.074 0.079 0.076 

a

 All data for year 2014 are preliminary. The 2014 data shown for the Temecula monitor 

reflects preliminary data from AQS for the first three quarters of 2014. The 2014 data for the 

Pechanga monitor reflects preliminary data for all four quarters. 

b

 The 1997 8-hour ozone standard is attained where the design value is less than or equal to 

0.08 ppm. See 40 CFR part 50, appendix I. Given the rounding conventions, however, 

attainment is achieved where design values are 0.084 ppm or less. See 40 CFR part 50, 

appendix I, section 2.3. The design values in this table are well below the relevant ozone 

NAAQS. 

Source: AQS Data Summary Report, dated May 16, 2014; AQS Data Summary Report, 

dated February 25, 2015. 

The typical pattern for ozone levels along the southwest coast of California is low ozone levels along the 

coast from clean coastal air with increasing levels inland as precursors and temperatures increase. At 

times, ozone and its precursors can be transported along the coast, as described in Factor 3, below. Air 

monitoring stations show this pattern with coastal monitors in Southern California attaining the 2008 

ozone NAAQS (e.g., monitor numbers 060731008, 060592022, and 060591003) and inland monitors in 

Southern California violating (e.g., monitor numbers 060656001 and 060659001). See Appendix 3 of 

the 2008 8-hour ozone TSD. This area is also subject to inland transport from the South Coast Air Basin 

along the Interstate 15 freeway when winds are from the north. The Temecula monitor is approximately 

10 miles north of Pechanga’s Indian country. 

The analysis of available air quality data from Pechanga and proximate monitors suggest that Pechanga's 

areas of Indian country experience similar air quality to the surrounding areas. For additional discussion 

of this issue, please see the associated EPA action. 
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Factor 2: Emissions and Emissions-Related Data 

EPA evaluated emissions of ozone precursors, nitrogen oxides (NOx) and volatile organic compounds 

(VOC), and other emissions-related data that provide information on areas contributing to violating 

monitors. The Pechanga Reservation consists of 6,700 acres, and is home to approximately 500 tribal 

members. Pechanga has one major stationary source of ozone precursor emissions, the Pechanga Casino 

and Resort, within the tribal boundaries. Other sources of ozone precursor emissions include local traffic 

to and from the casino/resort, parking structures, golf course, gas station, and a recreational vehicle (RV) 

park. In its May 9, 2014 RR/MP, Pechanga provided emission inventories for stationary sources, area 

sources, and on-road mobile sources. Pechanga estimated the stationary source emissions of NOx to be 

0.029 tons per day and VOC to be 0.013 tons per day in 2012. Actual emissions from the Pechanga 

Casino and Resort (a current Clean Air Act Title V major source) reported to EPA were 6.5 tons per 

year of NOx in 2010 and less than 1 ton per year of VOC in 2010.3 EPA reexamined the mobile source 

emissions inventory as a result of public comments and we re-calculated vehicle emissions using 

EMFAC2011 emissions factors for year 2012 based on the following assumptions: 17,100 average daily 

vehicle trips associated with non-residents and 1,870 daily vehicle trips associated with residents;4 0.5 

miles per trip on the reservation for non-resident trips and 2.0 miles per trip on the reservation for trips 

by reservation residents; and a non-resident vehicle mix based on data from another Indian casino and 

resort. Resident trips were assumed to be light-duty autos and trucks. For year 2025, we conservatively 

increased non-resident vehicle trips by 33% and estimated the corresponding emissions using year 2025 

emissions factors from EMFAC2011. Interim year (2015 and 2020) emissions were estimated by 

interpolating the number of trips between 2012 and 2025 and using the applicable year’s EMFAC2011 

emissions rates. We present the revised emissions estimates in table 3 below, which presents the same 

emissions inventory information as table 2 from the proposed rule except for the revised estimates for 

the Pechanga Reservation.5

 

3 See letter from Syndi Smallwood to Deborah Jordan, November 4, 2011. 

4 The average daily trip value for non-residents is based on a trip generation rate of 4.5 daily trips per slot machine from 

the Draft Tribal Environmental Impact Report for the Pala Casino and Spa Expansion Project (November 28, 2006), page 59. 
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Table 3 — Ozone Precursor Emissions Estimates for Pechanga Reservation and South 

Coast, 2012, 2015, 2020 and 2025 

(summer-day average, tons per day) 

Ozone 

Precursor 2012 2015 2020 2025 

Pechanga Reservation (Based on data as shown in Maintenance Plan except for on-road 

emissions, which are calculated by the EPA): 

VOC 0.151 0.123 0.094 0.081

NOx 0.088 0.082 0.072 0.065

South Coast (Based on CARB data as shown in Maintenance Plan rounded to the nearest 10 

tons): 

VOC 500 460 420 410

NOx 490 430 340 280

South Coast (Based on 2012 South Coast AQMP data rounded to the nearest 10 tons): 

VOC 540 480 450 440

NOx 560 470 370 310

Based on the revised calculations for on-road emissions at the Pechanga Reservation, emissions at the 

Pechanga Reservation are estimated to be several times higher than presented in the Pechanga Ozone 

Maintenance Plan and in the proposed rule but are predicted to decrease through the maintenance period 

due to significant reductions in vehicular emissions resulting from continued implementation of state 

and federal motor vehicle control programs. Moreover, our conclusion from the proposed rule that the 

emissions associated with the Pechanga Reservation are minimal in relation to regional ozone precursor 

emissions remains unchanged given that, even as revised, Pechanga Reservation emissions represent 

0.03% or less of regional emissions of VOC and NOx for all of the years that were analyzed. For 

additional discussion, please see the associated EPA action. 

Factor 3: Meteorology (weather/transport patterns) 

EPA evaluated available meteorological data to help determine how meteorological conditions, such as 

weather, transport patterns and stagnation conditions, would affect the fate and transport of precursor 

emissions contributing to ozone formation. Pechanga is located about 25 miles inland and experiences 

similar complex meteorology and transport patterns as inland parts of western San Diego County. 

Transport of ozone and its precursors to Pechanga is prevalent from the South Coast Air Basin. EPA 

also reviewed other sources of information that reaffirm that ozone levels in inland areas such as 

Pechanga can be influenced as a result of transport from the South Coast Air Basin.6 Transport patterns 

 

Resident trips assumed 10 daily trips per dwelling unit. Non-resident vehicle mix is assumed to be the same as that used to 

calculate vehicle emissions for the Graton Resort and Casino project. 

5 Documentation for the revised on-road motor vehicle emissions estimates is contained in a document titled “Pechanga 

Casino – Emissions Inventory,” dated March 16, 2015. 

6 Bigler-Engler, V, 1995: Analysis of an Ozone Episode during the San Diego Air Quality Study: The Significance of 

Transport Aloft. Journal of Applied Meteorology, 34, 1863-1875). Luria, M, 2005: Local and Transported pollution of San 

Diego, California. Atmospheric Environment, 39, 6765-6776. Boucouvala, D, 2003: Analysis of transport patterns during an 
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and meteorology suggest that Pechanga's areas of Indian country experience similar air quality to the 

surrounding nonattainment areas. For additional discussion, please see the associated EPA action. 

Factor 4: Geography/topography (mountain ranges or other air basin boundaries) 

The geography/topography analysis evaluates the physical features of the land that might affect the 

airshed and, therefore, the distribution of ozone over the area. The Pechanga reservation consists of 

6,700 acres located in northwestern portion of the Cleveland National Forest, ranging between 1,100 and 

2,600 feet in elevation. It is located in the northern portion of the San Diego-Carlsbad-San Marcos 

MSA and the southern part of the Los Angeles-Long Beach-Santa Ana MSA. The Pechanga’s lands do 

not have any geographical or topographical barriers that would prevent air pollution transport from the 

surrounding Los Angeles-South Coast Air Basin nonattainment areas. Although the terrain is complex, 

there are no topographic barriers, suggesting that Pechanga's areas of Indian country may experience 

similar air quality to the surrounding nonattainment areas. For additional discussion, please see the 

associated EPA action. 

Factor 5: Jurisdictional boundaries 

For each potential nonattainment area, we considered existing jurisdictional boundaries to provide a 

clearly defined boundary and to help identify the areas appropriate for carrying out the air quality 

planning and enforcement functions for nonattainment areas. Examples of jurisdictional boundaries 

include existing/prior nonattainment area boundaries for ozone or other urban-scale pollutants, county 

lines, air district boundaries, township boundaries, areas covered by a metropolitan planning 

organization, state lines, Indian country boundaries, and urban growth boundary. Where existing 

jurisdictional boundaries were not adequate or appropriate to describe the nonattainment area, other 

clearly defined and permanent landmarks or geographic coordinates are considered. 

As defined at 18 U.S.C. 1151, “Indian country” refers to: “(a) all land within the limits of any Indian 

reservation under the jurisdiction of the United States Government, notwithstanding the issuance of any 

patent, and, including rights-of-way running through the reservation, (b) all dependent Indian communities 

within the borders of the United States whether within the original or subsequently acquired territory 

thereof, and whether within or without the limits of a state, and (c) all Indian allotments, the Indian titles to 

which have not been extinguished, including rights-of-way running through the same.” EPA recognizes the 

sovereignty of tribal governments, and has attempted to take the desires of Pechanga into account in 

establishing an appropriate nonattainment area boundary for the tribe. 

Pechanga is a federally recognized tribe located in the northern portion of the San Diego-Carlsbad-San 

Marcos MSA and the southern part of the Los Angeles-Long Beach-Santa Ana MSA. Map 18a in 

Appendix 2 of the 2008 8-hour ozone TSD shows the location of areas of Indian country. 

EPA’s assessment of the jurisdictional factor was performed in accordance with the Tribal Designations 

Policy. The policy stresses the importance of recognizing tribal sovereignty and the jurisdictional status 

of Indian country in the decision-making process. It also articulates circumstances under which the 

 

SCOS97-NARSTO episode. Atmospheric Environment, 37 Supplement No. 2, S73-S94. Meteorological and Photochemical 

Modeling for the San Diego County 2007, 8 Hour Ozone State Implementation Plan. 
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jurisdictional boundaries factor could bear the most weight when evaluating a tribe's multi-factor 

analysis. 

The policy states that it may be appropriate to apply the most weight to the jurisdiction factor in a 

situation where a Tribe recommends being designated as a separate attainment area from an adjacent 

nonattainment area when a regulatory monitor in Indian country demonstrates that the NAAQS is being 

met, and there are no sources in Indian country contributing to nonattainment in the adjacent area based 

on an analysis of factors. As Pechanga has a regulatory monitor in its areas of Indian country and a 

proximate State-run monitor that both demonstrate the NAAQS is being met, EPA believes a separate 

attainment area designation is appropriate. 

The policy also states that it may be appropriate to apply the most weight to the jurisdiction factor in a 

situation where a Tribe recommends being designated as a separate attainment area from an adjacent 

nonattainment area when an analysis of the factors indicates that there are no sources in Indian country 

contributing to nonattainment in the adjacent area. Although Pechanga's areas of Indian country do 

contain stationary and mobile sources of ozone precursors, the magnitude of ozone precursor emissions 

is very small compared to emissions from the adjacent Los Angeles-South Coast Air Basin and San 

Diego County nonattainment areas, and thus, EPA is assigning more weight to Factor 5: Jurisdiction. 

For additional discussion, please see the associated EPA action.