UNITED STATES ENVIRONMENTAL PROTECTIONAGENCY WASHINGTON, D.C. 20460

MEMORANDUM OFFICE OF AIR AND RADIATION

SUBJECT: Designations for the Fine Particle National Ambient Air Quality Standards

FROM: Jeffrey R.



### w TO: Regional Administrators,Regions 

### I-X This memorandum provides guidance to State and local air pollution control agencies and Tribes on the process for designatingareas for the purpose of implementing the fine particle national ambient air quality standards. The EPA plans to issue final designationson December 15,2004. This memorandum describes the process for developing State and Tribal recommendations on designationsand the time line for EPA action leading to the final designations. The EPA promulgated the air quality standards for fine particulate matter (known as PM2,5) on July 18, 

### 1997 (62 Federal Register 38652). The standards were based on a number of health studies showing that increased exposureto PM2,, is correlated with increased mortality and
a range of serious health effects, including aggravation of lung disease, asthma attacks, and heart problems. Estimates show that attainment ofthese standards would result in tens ofthousands fewer premature deaths each year and would prevent tens of thousands ofhospital admissions and millions ofwork absences and respiratory illnesses in children annually. The designation process for PM,,, that is outlinedbelow is the next step toward developing and implementing emission control programs that will address this important public health problem. The first step in the designation process is the submittal of State and Tribal recommendations. The EPA requeststhat States and Tribes provide a list ofrecommended designationsto EPA by February 15,2004. The EPA plans to announce its intended designations in July 2004 and will provide 120 days for States and Tribes to comment on any modifications that EPA makes to the recommended designations. We plan to publish final PM2.3designations for all areas on December 15,2004. We also intend to propose and finalize its implementation rule for PM,,, early enough to be taken into consideration during the designationprocess. The EPA hopes that by following a designation schedule for PM,,, similar to that for the 8-hour ozone program, the States and Tribes will be able to harmonize area boundaries and future control strategiesto the extentpossible.

Internet Address (URL) http://www.epa.gov RecycledlRecyclable Printed with VegetableOil Based Inks on Recycled Paper (Minimum 50% Postconsumer content)As explained in this guidance, we intend to apply a presumption that the boundaries for urban nonattainment areas should be based on MetropolitanArea boundaries. A metropolitan area, as definedby the Office ofManagement and Budget, may consist of a single Metropolitan StatisticalArea in some cases, and a ConsolidatedMetropolitan Statistical Area in other cases. These metropolitan areas providepresumptive boundaries for the geographic extent of urban
areas. The presumptiveuse ofmetropolitan area boundaries to define urban nonattainment areas is based on recent evidence that violations of the PM2,,air quality standards generally include a significanturban-scale contributionas well as a significant larger-scale regional contribution. For rural areas that are identified as violating the PM2,,standards, the guidance sets forth EPA's presumption that the full county shouldbe designated nonattainment. The approach taken in this guidance is similar to our approach to designations for the 8-how ozone standard, and we wge States and Tribes to harmonize their ozone and PM,., designation recommendations where appropriate. Two attachments provide additional information and guidance. Attachment 1is a time line of important dates in the fine particle NAAQS implementation process. Attachment 2 is a series of questions and answers providing more detailed guidance, including discussion of several factors to be consideredin evaluatingwhether modificationsto nonattainment area boundaries are appropriate.

This memorandum provides EPA's current views on how boundaries should be determined for designations. Thsguidance is not binding on States, Tribes, the public, or EPA. Issues concerning nonattainment area boundaries will be addressed in actions to designate nonattainment and attainrnent/unclassifiableareas under section 107 and section 301(d) of the Clean Air Act (Act). When EPA promulgates designations,that action will be final and binding
on States, Tribes, the public, and EPA as a matter of law.
Staffin EPA's regional offices and the Office ofAir Quality Planning and Standards are available for assistance and consultationthroughout the designationprocess. Questions on this guidance may be directed to Tom Rosendahl at 919-541-5314or Rich Darnberg at 919-541-5592. The Regional Offices should make this guidance availableto their States and Tribes and work closely with them to ensurethey submit their arearecommendationsand supporting information by February 15,2004.

Attachments: 2

cc: Stephen D. Page, OAQPS Air Division Directors,Regions 

### I-X Margo Oge, OTAQ Brian McLean, OAP Elizabeth Cotsworth, ORIAATTACHMENT 1



### TIME LINE 

### FOR PM,, NAAQS 

### IMPLEMENTATION PROGRAM
Date 

# I Item I September 2003 

# I EPA issues proposed PM2.,implementationrule
I

July 2004 February 15,2004



### EPA notifies States and Tribes concerning anymodifications to their recommendations. State and Tribal recommendations due for PM2,5 designations

- Recommendations canbe based on 2000-2002 data

December 2007 

# 1 State implementation plans are due for PM,,, nonattainrnent areas (3 p~ September 2004
December 15,2004 

# Iyears after designation date).
I EPA issues final PM,,, implementation rule

EPA issues final PM2,,designations.

December 2009- 2014 Date for attaining PM2.3 standards (5 years after designation date).

- An extension ofup to five years is possible with an adequate demonstration.ATTACHMENT 2


### GUIDANCE ON NONATTAINMENT AREA DESIGNATIONS FOR PM2,

1. 

### What are the underlying requirements for designating areas for the PM2, NAAQS? Requirements for area designations are found in section 107 of the Clean Air Act (Act). Upon promulgation of a new or revised national ambient air quality standard (NAAQS)', States
are required under section 107(d)ofthe Act to submit to EPA a recommended list of areas for designation as attainment, nonattainment, or unclassifiable. While the language of Section 107 specifically addresses States, EPA will follow the sameprocess for Tribes to the extent practicable, pursuant to Sections 110(o) and 301(d) of the Act and the Tribal Authority Rule, or 

### TAR.^

Section 107(d) specifies that nonattainment areas shall include "any area that does not meet (or that contributes to ambient air quality in a nearby area that does not meet) the national primary or secondary ambient air quality standard for the pollutant." Interpretation oftlvs requirement is a keypurpose of thsguidance.

Section 107 further specifies a timetable for action on designations. Under section 107(d)(l), States are to submit recommendations within one year after promulgation of a new or revised standard. Under section 107(d)(l)(B)(ii), if EPA intends to promulgate a designation that deviates fi-omthe Staterecommendation, it must notify the State at least 120 days before promulgating the modified designation, and EPA must provide the Statethe opportunity to comment on the potential modification. EPA should promulgate designations within two years after promulgation of a new or revised standard, with apossible one year extension ifEPA has insufficient information. The Transportation Equity Act for the 21st Century (TEA-2 1) of 1998 amended the timetable for PM2,,designations, based on the recognition that the monitoring network first needed to be deployed to collect sufficient monitoring data to designate areas. Under section 6102(c)(l) of TEA-21, States are required to submit recommended area designations to EPA within 1year after receipt of 

### 3 years of air quality monitoring data obtained with federal reference (or equivalent) monitoring methods. Section 6102(d) requires EPA to promulgate designations within 1year after State recommendations are due, but no later than December 3 1, 2005. Although the TAR provides Tribes with flexibility in meeting the schedules set forth in 

# ' EPA promulgated the NAAQS for PM2,,on July 18, 1997. See 62 Federal Register 38652. The annual standard for PM2.,was set at a level of 15 pg/m3,based on the 3-year average of annual arithmetic mean PM2,,concentrations. The 24-hour standard was set at a level of 65 pg/m3,based on the 3-year average ofthe 9Vh percentile of 24-hour PM2,,concentrations.
2The"Tribal Authority Rule," promulgated on February 12, 1998, specifies that Tribes shallbe treated as States in selected cases as appropriate. See 63 FR 7254, codified at 40 Code ofFederal Regulations (CFR) Part 49 (1998).the Act, EPA has the obligation to designate areas consistent with the schedules in the Act. Therefore, EPA will designate Tribal areas, in consultation with the Tribes, on the same schedule
as State designations. Stateimplementation plans designed to meet the standards are then due within three years ofthe date of designation (e.g. December 2007) in accordance with section 172 of the Act.

2. 

### What are the key milestones of the 

### PM,, designations process?

The milestones of the 

### PM,,, designation process are listed in Attachment 1. 

### In developing these milestones, we considered that implementation of the TEA-21 schedule for designations could be complicated by the variety of dates on which various locations first have 3 years of data available. Some siteshad 3 years of data available as of July 2002, other sites did not have 3 years of data until later in 2002, and some sites will not have 3 years of data until July 2003. This approach could result in designations occurring between July 2004 and July 2005. EPA believes that a staggered designation schedule, which would yield staggered implementation plan deadlines, would hamper the regional and metropolitan area-based coordination that isneeded among various governments and stakeholders. Therefore, thsguidance contains single dates for StateITribalrecommendations and final designationsby EPA. EPA requests that all State and Tribal recommendations be submitted by February 15, 2004. Consistent with TEA-21 time frames, EPA plans to designate all areas by December 15, 2004. States and Tribes will be able to use the 2000-2002 data in their recommendations. Areas should be identified as "nonattainment" (violating a standard or contributing to nearby violations), or as "attainment/unclassifiable" (either meeting the standard or having insufficient data to determine air quality, and not contributing to nearby nonattainment). EPA intends to promulgate area designations in terms ofthese two categories. State recommendations do not applyto Indian country.
After EPA evaluates the recommendations it receives, EPA will notify States and Tribes of any modifications it intends to make to their recommendations at least 120days before the designations are to be finali~ed.~ If a State or Tribe disagrees with any change, it may provide information to EPA to demonstrate why it believes that the proposed modification is inappropriate, and EPA will consider this information in developing the final list of area designations. 

### In their comments, States and Tribes may take into account the 2001 to 2003 monitoring data, which EPA expects to be available before comments are due. As noted above, EPA7s policy is to use the most recent three years of data available at the time of designations.

3EPA'slegal obligation to provide 120 days notice ofmodifications applies only to those Tribes that have sought and received formal authority to recommend designations pursuant to the Tribal Authority Rule. However, EPA is soliciting Tribal recommendations and intends to provide 120 days notice of any modifications irrespective of whether a Tribe has this formal authority.EPA plans to promulgate final designations on December 15,2004and intends to consider the 2001 to 2003 data in making these designations.

The EPA is committedto ensuringthat all stakeholders have an opportunity to participate in the designation process for the PM,,, NAAQS, and that State, local and Tribal officials have ample time to comply with obligationsthat are triggered by designations. States and Tribes are encouraged to involve their stakeholders in developing their recommendations. Regional Offices should work with States and Tribes,particularly for areas where a monitor is recording a violation of the PM2,,standards. If a State or Tribe does not provide any designation recommendations for specific areas, EPA will promulgatethe designationsit deems appropriate.

3. 

### How are violations identified? The first step in definingnonattainment areas is to identify monitoring sites at whch air quality does not meet either the annual or 24 hour standard for PM,,,. Appendix N to 40 CFR Part 50 specifies the procedures to be used to analyze whether air quality at any site meets the air quality standards. Procedures associatedwith data handling and calculations for comparing data to the PM,., standards are described in more detail in the "Guideline on Data Handling Conventions for the 

### PM NAAQS" (EPA-454/R-99-008, 1999). The EPA's designation of areas will be based on the most recent 3 consecutivecalendar years of air quality data fiom Federal reference or equivalentmethod monitors. Data used must be quality-assuredand meet 40 CFR part 58 requirements (e.g., for monitor siting). Many areas collect additional data on particulate matter composition using the InteragencyMonitoring for Protecting Visual Environments (IMPROVE)protocol or using methods of the speciationtrends network. These methods are not Federal reference methods or equivalent methods, and data collected according to these methods should not be used to determine the existence of a violation. However, as noted in 40 CFR 58 (Appendix C, section 2.9) with respect to IMPROVEprotocol monitors, these methods may be used to estimate background concentrationsand thus maybe used to assess the geographic extent ofthe area contributing to a nonattainment situation.

The air quality standards for PM,,, specify two exceptional circumstancesin which concentrations above the level of the standard are not to be interpreted as violating the standard. The first exception is that sites that monitor source-oriented hot spots in some cases should be assessed only with respect to the 24-hour standard,not the annual average standard. 

### In 40 CFR Part 58 (Appendix 

### D, section 2.8.1.2.3),EPA statesthat monitoring sites representing unique localized conditions not found elsewhere in the area should not be compared with the annual average standard. For sites that States or Tribes have designated as hot-spot sites, EPA must review whether available evidence confirmsthat the annual average concentrationsat the site are in fact unrepresentative of conditions elsewhere in the region. If so, data fiom the site will not be compared against the annual standard, but it will be compared against the 24-hour standard.The second exception arises when the option of spatial averaging is applied, which may result in a group of monitors collectively indicating attainment of the annual average standard,
even though individual monitors in the group may show average concentrations which do not meet the standard. Conversely, spatial averaging could indicate nonattainment for the area even though some monitors show concentrations which meet the standard. Appendix 

### N of 40 CFR Part 50 offers the option of applying spatial averaging in the analysis for the annual average standard. For a State or Tribe to apply spatial averaging, it must have previously designated PM2.5monitors for spatial averaging as 

### an element ofits PM,,, monitoring plan, and it must have provided a suitable opportunityfor the public to comment on this intent.4

Monitors with data to be averaged must satisfy detailed criteria given in 40 CFR Part 58 (Appendix 

### D, section 2.8.1.6). Sites within an identified area that meet these criteria will be addressed on a spatially averaged basis only if the State or Tribe opts to do so. For monitors that satisfy these criteria, the procedures for averagingthe qualifying data are given in Appendix

### N to 40 CFR Part 50 and the aforementioned data handling guidance. A determination would be made as to whether the spatiallyaveraged annual average meets or does not meet the annual average standard, irrespective ofwhether concentrationsat any individual site meet or do not meet the annual standard.

4. 

### How should boundaries of urban nonattainment areas be determined? Are there presumptive boundaries for nonattainment areas?

As noted above, a nonattainment area must be defined not onlyto include the area that is violating the standard,but also to include the nearby source areas that contribute to the violation. Thus, a key factor in settingboundaries for nonattainment areas is determiningthe geographic extent of nearby source areas contributing to the nonattainment problem. For each monitor or group ofmonitors that exceed a standard, nonattainmentboundaries must be set that include a sufficiently large area to include both the area judged to violate the standard and the source areas that contribute to these violations. Evaluations of source areas must account for sources ofPM2,, precursors (such as sulfur dioxide,nitrogen oxides, ammonia, and some volatile organic compounds) as well as sources of direct PM,., emissions.

EPA has examined various evidence addressing the typical geographic scale of source areas that contribute to violations of the PM,,, standard. This evidence indicates substantial contributionsto violations of the PM,,, standard both from long-range transport5and fi-omthe collection of urban sources dispersed within metropolitan areas. To assess the metropolitan scale

See 40 CFR 

### Part 58.20(f) and 40 CFR Part 58.26(e) for information about public notification and public comment requirements associated with spatial averaging.
See discussion of long-range transport of sulfate and nitrate particles in supporting materials for the Clear SkiesAct at http://www.epa.~ov/clearsl~ies/.contribution, EPA examined the geographic distribution of total PM,,, concentrationsin and near many metropolitan areas. EPA found an associationofhigher PM2,,concentrations with greater levels of urban activity. Comparisons of rural versus urban concentrations of the components of PM2, indicate that certain components (such as carbonaceous particles and nitrates) resulting in part from urban emissions are found in significantlyhigher concentrationsin urban areas.6 These "urban emissions" arise from human activities, such as motor vehicle use and home heating as well as industrial activities, that occur with greater density in more populated areas. The metropolitan area, as delineated by the Office ofManagement and Budget (OMB), provides a presumptive definition ofthe populated area associated with a core urban area.7 Accordingly, EPA believes that the metropolitan areaprovides a presumptive definition of the source area that contributesto a PM2,5 nonattainment problem. For this reason, EPA believes that the Metropolitan Area should serve as the presumptive boundary for urban PM2.3NAAQS nonattainment areas. This presumption reflects EPA's view that, in the absence of evidence to the contrary, violations of the PM,,, NAAQS in urban areas may be presumed attributable at least in part to contributionsfrom sources distributed throughout the Metropolitan Area. This approachparallels the presumptive metropolitan area boundaries established in the 1990 Amendments to the CAA for certain ozone nonattainment areas. "Metropolitan areas" are defined by the Office ofManagement and Budgetbased on data collected by the U.S. Bureau ofthe Census. 

### In each case, a metropolitan area includes a core urban areaplus the full set of associated nearby communities. These areas in some cases include
a single Metropolitan Statistical Area (MSA) that is not associated with and is typicallynot contiguous with any other MSA, and in other cases include multiple contiguous Primary Metropolitan Statistical Areas (PMSA) which collectivelyform a Consolidated Metropolitan StatisticalArea. 

### In MetropolitanAreas consisting of a singleMSA, EPA presumes the entire MSA shouldbe designated as nonattainment. 

### In Metropolitan Areas consisting ofmultiple PMSA's which collectivelyform a Consolidated Metropolitan StatisticalArea, EPA presumes the entire Consolidated Metropolitan Statistical Area should be designated nonattainment.

EPA anticipatesthat OMB will publish revised metropolitan area lists later in 2003. Unfortunately, this publication may not occur early enough for States and Tribes to consider the revised lists in the developmentofrecommended designations for PM,,,. Furthermore, EPA seeks to maximize consistencybetween designationsfor PM2,,and designationsfor the 8-hour
ozone standard. The earlier timetable for ozone designations makes it even less likely that revised metropolitan area lists will be availablefor State and Tribal considerationin recommending

V. Rao, N. Frank, A. Rush, 

### F. Dimmick, "Chemical Speciation ofPM2,, in Urban and Rural Areas", in the Proceedings of the Air & Waste Management Association Symposium on Air Quality Measurement Methods and Technology, San Francisco,November 13-15,2002.
For further information on the definitions ofmetropolitan areas, see: 

### http://www.census.gov/population/www/estimates/metroarea.html.ozone designations. Therefore, EPA anticipates relying on the current metropolitan area definitions, published by OMB on June 

### 30, 1999,in establishing presumptive nonattainment area boundaries.

EPA will consider State, local, and Tribal recommendations ofnonattainment area boundaries that deviate from metropolitan area boundaries based on various factors. These factors are discussed in question 5 below. Consideration ofthese factors may warrant a nonattainment area that has additions and/or deletions relativeto OMB's defined metropolitan
area.
Boundariesused for implementation of the 8-hour ozone standard may also be 

### an important factor in determining boundaries for PM,, nonattainment areas. Indeed, there are many areas that violate both the 8-hour ozone and the PM2,3 standards, and States and Tribes may wish the nonattainment boundaries for the two pollutants to be identical in order to coordinate air qualityplanning, control strategydevelopment, and the implementationofthe transportation conformityprogram.
We recognize that, unlike ozonenonattainment problems, there are situations where nonattainment of the PM,,, NAAQS can arise on a very localized basis. For example, violations
can be caused by the emissionsfrom a single major source or set of sources, in some cases exacerbatedby severelyrestricted atmospheric dispersion (such as a narrow mountain valley). In such cases, the State or Tribe should further investigate the causes ofthe violation and the geographic extent of the violation. Therecommended boundaries ofthe nonattainment area should then reflect a case-specific judgment of the area sufficientto include the areas violating the PM2,3 NAAQS plus any additional source areas contributing to the violation. The State or Tribe will need to provide an adequatejustification demonstrating that a smaller area would include the full area that is violating the standards and all nearby source areas that contributeto the violation. EPA expects there to be a limited number of situations ofthis type.

5. 

### What factors will EPA 

### consider as the basis for a State or Tribal request for an alternative urban area definition?



### In some cases, a State or Tribe may find that a violation of the PM,,, standardis attributed to a significant metropolitan-scalecomponent and yet believe that the Metropolitan Area does not appropriately define the area that should be designated nonattainment. EPA will consider requests for urban nonattainmentarea definitions that deviatefrom OMB's metropolitan area definitions on a case-by-casebasis, considering the factors described below. These factors resemble the factors identifiedin previousEPA guidance on 8-hour ozone nonattainment boundaries, though EPA will make its decisions based on the distribution of sources contributing to PM,,, concentrations. EPA will apply these same factors in evaluating boundary modifications for both States and Tribes. PM2,, is a regional pollutant, and sources of PM2,,and its precursors are numerous and located over a broad area. For this reason, EPA believes it would be unlikelythat we would designate any area as attainment that is surrounded on all sides by nonattainment
areas.
EPA will consider the following factors in assessing whether to exclude'portions of a metropolitan area and whether to include additional nearby areas outside the metropolitan area as part of the designated nonattainment area:

Emissions in areas potentially included versus excluded from the nonattainment area Air quality in potentially included versus excluded areas Population density and degree ofurbanization including commercial development in included versus excluded areas Traffic and commuting patterns Expected growth (including extent, pattern and rate of growth) Meteorology (weatherltransportpatterns) Geographyltopography (mountain ranges or other air basin boundaries) Jurisdictional boundaries (e.g., counties, air districts, Reservations, etc.) Level of control of emission sources Analyses ofthese factors may suggest nonattainment boundaries that are either larger or smaller than the metropolitan area. A demonstration supporting the designation ofboundaries that are less than the full metropolitan area must show both that violations are not occurring in the excluded portions ofthe metropolitan area and that the excluded portions are not source areas that contribute to the observed violations. A State or Tribal submittal that only addresses whether violations are occurring throughout the area will not suffice as a justification for designating a nonattainment area smaller than the metropolitan area. States and Tribes are encouragedtojustify such recommendations by addressing all of the factors identified above. Recommendations to designate a nonattainment area larger than the metropolitan area should also be based on an analysis ofthese factors. EPA will consider these factors in evaluating State and Tribal recommendations and assessing whether any modifications are appropriate. Air quality dispersion modeling and data interpolation techniques can be useful tools to help assess how air quality in unmonitored areas compares to air quality at monitoring sites. Accordingly, these tools can help assess the geographic area violating andlor contributing to a violation of the standards. EPA and others are und&takingvarious efforts to improve the reliability ofthese tools. 

### In determining whether an analysis appropriately justifies modified nonattainment area boundaries, EPA will give particular consideration to the reliability of the relevant modeling or interpolation technique.



### 6. How should designation recommendations, including boundaries, be addressed when
more than one State or Tribe might be affected?

Where more than one State or Tribe is involved in an area, close coordination is neededamong the affected States and Tribes prior to the time the recommendation is made. 

### In addition, the EPA Regional Office should coordinate where an area may be located in States or tribal lands located in two or more regions. There is a strongpresumption that interstate areas making up one metropolitan area will be designated as one nonattainment area. The EPA strongly encourages States and Tribes involved in multi-jurisdictionalareas to make consistent and coordinated boundary recommendations.

7. 

### How will 

### EPA address rural areas? Previous questionshave addressed urban areas, presumptively defined as metropolitan
areas surrounding core cities, with potential boundary adjustments based on a variety of factors. This question addressesrural areas, defined here to mean counties or areas not included in or adjacent to such urban areas. An area found to violate the standard that is adjacent to a metropolitan area.wil1generallybe designated as part of that urban nonattainment area and would. not be treated as rural forpurposes ofthis guidance.

As with urban areas, the first step in determiningattainment status for rural areasis to evaluate available air qualitydata measured by FederaI reference method monitors. The second step is to assess the boundaries ofthe airsheds represented by the rural monitors and determine the source areas contributingto air quality at these monitors. For cases in which rural data indicate nonattainment, the nonattainment area again must be sufficientto include the full area that is violating the standardsas well as any nearby source areas that are contributing to the violation.

When a rural monitor violates the standard, EPA intends to apply a presumption that the nonattainment area shall include the full county in which the monitor is located. EPA will considerrecommendationsto adjust rural area nonattainment boundariesbased on the same factors as it applies to urban areas, as discussed in question 5 above. Using these factors, a State
or Tribe that recommendsthat a smaller area should be designated nonattainment shouldprovide convincing evidence that the monitor is not representative ofthe full county, that the excluded portions of the county are not source areas contributingto the nonattainment, and that the excludedportions of the county are meeting the standard. Similarly, a State or Tribe may recommend that a larger areabe designated nonattainmentbased on technical information relevant to these factors. Nevertheless, as discussed above, if nonattainment'is demonstrably very localized and is attributableto localized sources,

### EPA intends to establish nonattainment
areaboundaries based on a case-specific evaluation of the nature and extent of the problem.

8. 

### What additional documentation should a State or Tribal government submit concerning the nonattainment area recommendations?



### Ln addition to technical information documenting the recommendation for areaboundaries noted in question number 

### 5 above, the EPA is requesting that each State or Tribe in its submission provide certain air quality data and geographic information to support its nonattainment area recommendation. The EPA is asking for the following information:

For nonattainment areas: a. PM2,5 design value for the area. b. Three year period represented by the design value, e.g., 2000-2002
c. Design value monitoring site location(s) and identificationnumber(s).

For 

### attainment/unclassifiable

### AND nonattainment areas: d.. Names of counties and tribal lands included, and
e. Ifpartial counties or portions oftribal lands are included, the boundary definitioddescription as outlined below.

If the recommended nonattainment areaboundary is smaller than the metropolitan area definition, the State or Tribe should document its rationale for selecting the nonattainment area boundary. The documentation should address how all the factors discussedin question number 5 (such as population, traffic and commutingpatterns, commercial development, projected growth, prevailing meteorology, nearby sources and air quality, and any other relevant or technical justification factors) affect the drawing ofboundaries for each county or other sub-area not included in the recommended nonattainment area. In particular, where the recommended area boundary consists of parts of counties,metropolitan areas, or tribal lands, the State or Tribe must provide a technical analysis for its recommendation, explaininghow the boundary is consistent with 

## 5 107 (d)(l) ofthe Act.

Ifthe recommendation includes any partial counties, the EPA is requesting a legal definition of the area, a detailed hard copy map, and, because EPA plans to map each area, a digitized latitude and longitude description. The submittal should include the names of contacts for this information.

The EPA envisions making information on designation recommendations available electronically. Therefore, EPA requests that each State submit its designation recommendations, supporting documentation,and boundary information and associated maps to EPA in both a detailed written form and in electronicform.



### 9. 

### How is EPA 

### addressing Tribal concerns about the designations process?

Tribes are encouraged, but not required, to submit designation recommendationsfor their reservations or other areas under their jurisdiction to EPA. The TAR offers flexibility to Tribes for specificplan submittal and implementation deadlines for NMQS-related requirements, includingbut not limited to such deadlinesin CM sections 1 1 O(a)(l), 172(a)(2), 182, 187, 189,and 191. However, EPA is required by the Act to promulgate area designations accordingto a timetable. Therefore, if a Tribe wishes to participate in the designation process they must submit
a recommendation in time for EPA to consider that recommendation when making a designation. 

### In cases where Tribes do not make a recommendation, the EPA, upon consultationwith the respective Tribe(s), will promulgate the designation it deems appropriate.

EPA has discussed designation issues with many Tribal representativesand we recognize that there.are several issues ofparticular concern to Tribes. Some Tribes have expressed concern that where a violation is monitored in a metropolitan area that includes tribal lands, the tribal lands presumptively should not be part ofthe urban nonattainment area, because the tribal lands often are not politically and economically integrated with the urban area. EPA will addressthis
concern on a case-by-casebasis. Upon request, EPA will help any Tribe obtain relevant information addressing the factors described under question 5 above. As with State lands, EPA will use this information to helpjudge whether the tribal lands are meeting the air quality standards and whether the tribal lands are a source area contributingto nonattainment in the metropolitan area. EPA will designate the tribal lands based on this information.

Some Tribes have expressed concern about the use of monitors located on State lands to establish designationsfor tribal lands. Given EPA's obligationto promulgate designations for all locations, EPA by necessitymust judge the air quality ofunmonitored locations on the basis of monitoring data from other locations. Where a monitor indicates a violation of an air quality standard, EPA will designate a nonattainment area that includes unmonitored areas either that EPA judges also to be violating the standard or that EPAjudges to be a nearby source area contributing to the nonattainment. Some Tribes have also raised concerns with the designation process that they may not have the resources to do the detailed analysis necessary to prepare their recommendations. EPA offers to work with Tribes on their recommendations upon request.