UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

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 designating areas for the purpose of implementing the fine particle 

national ambient air quality standards. The EPA plans to issue final designations on 

December 15,2004. This memorandum describes the process for developing State and Tribal 

recommendations on designations and 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 exposure to 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 of these standards would result in tens of thousands 

fewer premature deaths each year and would prevent tens of thousands of hospital admissions 

and millions of work absences and respiratory illnesses in children annually. The designation 

process for PM,,, that is outlined below 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 requests that States and Tribes provide a list of recommended 

designations to 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 PM2.3 designations 

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 designation process. 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 

strategies to the extent possible. 

Internet Address (URL) http://www.epa.gov 

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As explained in this guidance, we intend to apply a presumption that the boundaries for 

urban nonattainment areas should be based on Metropolitan Area boundaries. A metropolitan 

area, as defined by the Office of Management and Budget, may consist of a single Metropolitan 

Statistical Area in some cases, and a Consolidated Metropolitan Statistical Area in other cases. 

These metropolitan areas provide presumptive boundaries for the geographic extent of urban 

areas. The presumptive use of metropolitan area boundaries to define urban nonattainment areas 

is based on recent evidence that violations of the PM2,, air quality standards generally include a 

significant urban-scale contribution as 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 should be 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 1 is 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 considered in evaluating whether modifications to nonattainment area 

boundaries are appropriate. 

This memorandum provides EPA's current views on how boundaries should be 

determined for designations. Ths guidance 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/unclassifiable areas 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. 

Staff in EPA's regional offices and the Office of Air Quality Planning and Standards are 

available for assistance and consultation throughout the designation process. Questions on this 

guidance may be directed to Tom Rosendahl at 919-541-5314 or Rich Darnberg at 919-541-5592. 

The Regional Offices should make this guidance available to their States and Tribes and work 

closely with them to ensure they submit their area recommendations and 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, ORIA 
ATTACHMENT 1 

TIME LINE FOR PM,, NAAQS IMPLEMENTATION PROGRAM 

Date I Item 

I 

September 2003 I EPA issues proposed PM2., implementation rule 

I 

July 2004 

February 15, 2004 

EPA notifies States and Tribes concerning any modifications to their 

recommendations. 

State and Tribal recommendations due for PM2,5 designations 

- Recommendations can be based on 2000-2002 data 

December 2007 1 State implementation plans are due for PM,,, nonattainrnent areas (3 

p~ 

September 2004 

December 15,2004 

I years 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 of up 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) of the 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 same process 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 of tlvs 

requirement is a key purpose of ths guidance. 

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-om the State recommendation, it must notify the State at least 120 days before 

promulgating the modified designation, and EPA must provide the State the opportunity to 

comment on the potential modification. EPA should promulgate designations within two years 

after promulgation of a new or revised standard, with a possible one year extension if EPA has 

insufficient information. 

The Transportation Equity Act for the 21 st 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 

6 102(c)(l) of TEA-21, States are required to submit recommended area designations to EPA 

within 1 year after receipt of 3 years of air quality monitoring data obtained with federal 

reference (or equivalent) monitoring methods. Section 61 02(d) requires EPA to promulgate 

designations within 1 year 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 of the 9Vh percentile of 24-hour PM2,, concentrations. 

2The "Tribal Authority Rule," promulgated on February 12, 1998, specifies that Tribes 

shall be treated as States in selected cases as appropriate. See 63 FR 7254, codified at 40 Code 

of Federal 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. State implementation plans designed to meet the standards are then due 

within three years of the 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 sites had 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 is needed 

among various governments and stakeholders. Therefore, ths guidance contains single dates for 

StateITribal recommendations and final designations by 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 of these two categories. State recommendations do not 

apply to 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 120 days 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's legal obligation to provide 120 days notice of modifications 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 15,2004 and intends to consider the 

2001 to 2003 data in making these designations. 

The EPA is committed to ensuring that 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 obligations that 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 promulgate the designations it deems appropriate. 

3. How are violations identified? 

The first step in defining nonattainment 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 associated with 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 consecutive calendar years of air quality data fiom Federal 

reference or equivalent method monitors. Data used must be quality-assured and meet 40 CFR 

part 58 requirements (e.g., for monitor siting). 

Many areas collect additional data on particulate matter composition using the 

Interagency Monitoring for Protecting Visual Environments (IMPROVE) protocol or using 

methods of the speciation trends 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 IMPROVE protocol monitors, these methods may be used to estimate 

background concentrations and thus may be used to assess the geographic extent of the area 

contributing to a nonattainment situation. 

The air quality standards for PM,,, specify two exceptional circumstances in 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 states that 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 confirms that the annual average concentrations at 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 

PM2.5 monitors for spatial averaging as an element of its PM,,, monitoring plan, and it must have 

provided a suitable opportunity for 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 averaging the 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 spatially averaged annual average meets or does not meet the annual 

average standard, irrespective of whether concentrations at 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 only to 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 setting boundaries for nonattainment areas is determining the geographic 

extent of nearby source areas contributing to the nonattainment problem. For each monitor or 

group of monitors that exceed a standard, nonattainment boundaries 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 of PM2,, 

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 

contributions to violations of the PM,,, standard both from long-range transport5 and fi-om the 

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 Skies Act at http://www.epa.~ov/clearsl~ies/. 
contribution, EPA examined the geographic distribution of total PM,,, concentrations in and near 

many metropolitan areas. EPA found an association of higher 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 significantly higher concentrations in 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 of Management and Budget (OMB), 

provides a presumptive definition of the populated area associated with a core urban area.7 

Accordingly, EPA believes that the metropolitan area provides a presumptive definition of the 

source area that contributes to a PM2,5 nonattainment problem. For this reason, EPA believes that 

the Metropolitan Area should serve as the presumptive boundary for urban PM2.3 NAAQS 

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 contributions from sources distributed throughout the Metropolitan Area. This 

approach parallels 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 of Management and Budget based on data 

collected by the U.S. Bureau of the Census. In each case, a metropolitan area includes a core 

urban area plus 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 typically not 

contiguous with any other MSA, and in other cases include multiple contiguous Primary 

Metropolitan Statistical Areas (PMSA) which collectively form a Consolidated Metropolitan 

Statistical Area. In Metropolitan Areas consisting of a single MSA, EPA presumes the entire 

MSA should be designated as nonattainment. In Metropolitan Areas consisting of multiple 

PMSA's which collectively form a Consolidated Metropolitan Statistical Area, EPA presumes 

the entire Consolidated Metropolitan Statistical Area should be designated nonattainment. 

EPA anticipates that 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 development of recommended designations for PM,,,. Furthermore, EPA 

seeks to maximize consistency between designations for PM2,, and designations for the 8-hour 

ozone standard. The earlier timetable for ozone designations makes it even less likely that revised 

metropolitan area lists will be available for State and Tribal consideration in recommending 

V. Rao, N. Frank, A. Rush, F. Dimmick, "Chemical Speciation of PM2,, 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 of metropolitan 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 of nonattainment area 

boundaries that deviate from metropolitan area boundaries based on various factors. These 

factors are discussed in question 5 below. Consideration of these factors may warrant a 

nonattainment area that has additions and/or deletions relative to OMB's defined metropolitan 

area. 

Boundaries used 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 

quality planning, control strategy development, and the implementation of the transportation 

conformity program. 

We recognize that, unlike ozone nonattainment 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 emissions from a single major source or set of sources, in some cases 

exacerbated by severely restricted atmospheric dispersion (such as a narrow mountain valley). 

In such cases, the State or Tribe should further investigate the causes of the violation and the 

geographic extent of the violation. The recommended boundaries of the nonattainment area 

should then reflect a case-specific judgment of the area sufficient to 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 adequate justification demonstrating that a smaller area would 

include the full area that is violating the standards and all nearby source areas that contribute to 

the violation. EPA expects there to be a limited number of situations of this 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,,, standard is attributed 

to a significant metropolitan-scale component and yet believe that the Metropolitan Area does 

not appropriately define the area that should be designated nonattainment. EPA will consider 

requests for urban nonattainment area definitions that deviate from OMB's metropolitan area 

definitions on a case-by-case basis, considering the factors described below. These factors 

resemble the factors identified in previous EPA 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 unlikely 
that 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 of urbanization including commercial development in 

included versus excluded areas 

Traffic and commuting patterns 

Expected growth (including extent, pattern and rate of growth) 

Meteorology (weatherltransport patterns) 

Geographyltopography (mountain ranges or other air basin boundaries) 

Jurisdictional boundaries (e.g., counties, air districts, Reservations, etc.) 

Level of control of emission sources 

Analyses of these factors may suggest nonattainment boundaries that are either larger or 

smaller than the metropolitan area. A demonstration supporting the designation of boundaries 

that are less than the full metropolitan area must show both that violations are not occurring in 

the excluded portions of the 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 

encouraged to justify 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 of these 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&taking various efforts to improve the 

reliability of these 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 needed 
among 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 strong presumption 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-jurisdictional areas to make consistent and 

coordinated boundary recommendations. 

7. How will EPA address rural areas? 

Previous questions have addressed urban areas, presumptively defined as metropolitan 

areas surrounding core cities, with potential boundary adjustments based on a variety of factors. 

This question addresses rural 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.wil1 generally be designated as part of that urban nonattainment area and would. 

not be treated as rural for purposes of this guidance. 

As with urban areas, the first step in determining attainment status for rural areas is to 

evaluate available air quality data measured by FederaI reference method monitors. The second 

step is to assess the boundaries of the airsheds represented by the rural monitors and determine 

the source areas contributing to air quality at these monitors. For cases in which rural data 

indicate nonattainment, the nonattainment area again must be sufficient to include the full area 

that is violating the standards as 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 

consider recommendations to adjust rural area nonattainment boundaries based on the same 

factors as it applies to urban areas, as discussed in question 5 above. Using these factors, a State 

or Tribe that recommends that a smaller area should be designated nonattainment should provide 

convincing evidence that the monitor is not representative of the full county, that the excluded 

portions of the county are not source areas contributing to the nonattainment, and that the 

excluded portions of the county are meeting the standard. Similarly, a State or Tribe may 

recommend that a larger area be designated nonattainment based on technical information 

relevant to these factors. Nevertheless, as discussed above, if nonattainment'is demonstrably 

very localized and is attributable to localized sources, EPA intends to establish nonattainment 

area boundaries 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 area 
boundaries 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 identification number(s). 

For attainment/unclassifiable AND nonattainment areas: 

d.. Names of counties and tribal lands included, and 

e. If partial counties or portions of tribal lands are included, the boundary 

definitioddescription as outlined below. 

If the recommended nonattainment area boundary 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 discussed in question number 5 

(such as population, traffic and commuting patterns, commercial development, projected growth, 

prevailing meteorology, nearby sources and air quality, and any other relevant or technical 

justification factors) affect the drawing of boundaries 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, explaining how the boundary is consistent 

with 5 107 (d)(l) of the Act. 

If the 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 electronic form. 

9. How is EPA addressing Tribal concerns about the designations process? 

Tribes are encouraged, but not required, to submit designation recommendations for their 

reservations or other areas under their jurisdiction to EPA. The TAR offers flexibility to Tribes 

for specific plan submittal and implementation deadlines for NMQS-related requirements, 

including but not limited to such deadlines in 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 according to 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 consultation with the 

respective Tribe(s), will promulgate the designation it deems appropriate. 

EPA has discussed designation issues with many Tribal representatives and we recognize 

that there. are several issues of particular 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 of the urban nonattainment area, because the tribal lands 

often are not politically and economically integrated with the urban area. EPA will address this 

concern on a case-by-case basis. 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 help judge whether the tribal lands are meeting the air quality 

standards and whether the tribal lands are a source area contributing to 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 designations for tribal lands. Given EPA's obligation to promulgate designations for all 

locations, EPA by necessity must judge the air quality of unmonitored 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 EPA judges 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.