Wednesday, 

March 24, 2010 

Part II 

Environmental 

Protection Agency 

40 CFR Part 93 

Transportation Conformity Rule PM2.5

and PM10 Amendments; Final Rule 


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14260 Federal Register / Vol. 75, No. 56 / Wednesday, March 24, 2010 / Rules and Regulations 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 93 

[EPA–HQ–OAR–2008–0540; FRL–9127–7] 

RIN 2060–AP29 

Transportation Conformity Rule PM2.5

and PM10 Amendments 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Final rule. 

SUMMARY: In this action, EPA is 

amending the transportation conformity 

rule to finalize provisions that were 

proposed on May 15, 2009. These 

amendments primarily affect 

conformity’s implementation in PM2.5

and PM10 nonattainment and 

maintenance areas. EPA is updating the 

transportation conformity regulation in 

light of an October 17, 2006 final rule 

that strengthened the 24-hour PM2.5

national ambient air quality standard 

(NAAQS) and revoked the annual PM10

NAAQS. In addition, EPA is clarifying 

the regulations concerning hot-spot 

analyses to address a December 2007 

remand from the Court of Appeals for 

the District of Columbia Circuit. This 

portion of the final rule applies to PM2.5

and PM10 nonattainment and 

maintenance areas as well as carbon 

monoxide nonattainment and 

maintenance areas. 

The Clean Air Act (CAA) requires 

federally supported transportation 

plans, transportation improvement 

programs, and projects to be consistent 

with (‘‘conform to’’) the purpose of the 

state air quality implementation plan. 

The U.S. Department of Transportation 

(DOT) is EPA’s federal partner in 

implementing the transportation 

conformity regulation. EPA has 

consulted with DOT, and they concur 

with this final rule. 

DATES: This final rule is effective on 

April 23, 2010. 

ADDRESSES: EPA has established a 

docket for this action under Docket ID 

No. EPA–HQ–OAR–2008–0540. All 

documents in the docket are listed on 

the http://www.regulations.gov Web 

site. Although listed in the index, some 

information is not publicly available, 

e.g., CBI or other information whose 

disclosure is restricted by statute. 

Certain other material, such as 

copyrighted material, is not placed on 

the Internet and will be publicly 

available only in hard copy form. 

Publicly available docket materials are 

available either electronically through 

http://www.regulations.gov or in hard 

copy at the Air and Radiation Docket, 

EPA/DC, EPA West, Room 3334, 1301 

Constitution Ave., NW., Washington, 

DC. The Public Reading Room is open 

from 8:30 a.m. to 4:30 p.m., Monday 

through Friday, excluding legal 

holidays. The telephone number for the 

Public Reading Room is (202) 566–1744 

and the telephone number for the Air 

and Radiation Docket is (202) 566–1742. 

FOR FURTHER INFORMATION CONTACT: 

Laura Berry, State Measures and 

Conformity Group, Transportation and 

Regional Programs Division, 

Environmental Protection Agency, 2000 

Traverwood Drive, Ann Arbor, MI 

48105, e-mail address: 

berry.laura@epa.gov, telephone number: 

(734) 214–4858, fax number: (734) 214– 

4052; or Patty Klavon, State Measures 

and Conformity Group, Transportation 

and Regional Programs Division, 

Environmental Protection Agency, 2000 

Traverwood Drive, Ann Arbor, MI 

48105, e-mail address: 

klavon.patty@epa.gov, telephone 

number: (734) 214–4476, fax number: 

(734) 214–4052. 

SUPPLEMENTARY INFORMATION: The 

contents of this preamble are listed in 

the following outline: 

I. General Information 

II. Background on the Transportation 

Conformity Rule 

III. General Overview of Transportation 

Conformity for the 2006 PM2.5 NAAQS 

IV. Baseline Year for Certain 2006 PM2.5

Nonattainment Areas 

V. Regional Conformity Tests in 2006 PM2.5

Nonattainment Areas That Do Not Have 

Adequate or Approved SIP Budgets for 

the 1997 PM2.5 NAAQS 

VI. Regional Conformity Tests in 2006 PM2.5

Areas That Have 1997 PM2.5 SIP Budgets 

VII. Other Conformity Requirements for 2006 

PM2.5 Areas 

VIII. Transportation Conformity in PM10

Nonattainment and Maintenance Areas 

and the Revocation of the Annual PM10

NAAQS 

IX. Response to the December 2007 Hot-Spot 

Court Decision 

X. Statutory and Executive Order Reviews 

I. General Information 

A. Does This Action Apply to Me? 

Entities potentially regulated by the 

conformity rule are those that adopt, 

approve, or fund transportation plans, 

programs, or projects under title 23 

U.S.C. or title 49 U.S.C. Regulated 

categories and entities affected by 

today’s action include: 

Category Examples of regulated entities 

Local government ...................................... Local transportation and air quality agencies, including metropolitan planning organizations (MPOs). 

State government ...................................... State transportation and air quality agencies. 

Federal government ................................... Department of Transportation (Federal Highway Administration (FHWA) and Federal Transit Administration (FTA)). 

This table is not intended to be 

exhaustive, but rather provides a guide 

for readers regarding entities likely to be 

affected by this final rule. This table 

lists the types of entities of which EPA 

is aware that potentially could be 

regulated by the transportation 

conformity rule. Other types of entities 

not listed in the table could also be 

regulated. To determine whether your 

organization is regulated by this action, 

you should carefully examine the 

applicability requirements in 40 CFR 

93.102. If you have questions regarding 

the applicability of this action to a 

particular entity, consult the persons 

listed in the preceding FOR FURTHER

INFORMATION CONTACT section. 

B. How Can I Get Copies of This 

Document? 

1. Docket 

EPA has established an official public 

docket for this action under Docket ID 

No. EPA–HQ–OAR–2008–0540. You can 

get a paper copy of this Federal Register 

document, as well as the documents 

specifically referenced in this action, 

any public comments received, and 

other information related to this action 

at the official public docket. See the 

ADDRESSES section for its location. 

2. Electronic Access 

You may access this Federal Register 

document electronically through EPA’s 

Transportation Conformity Web site at 

http://www.epa.gov/otaq/ 

stateresources/transconf/index.htm. 

You may also access this document 

electronically under the Federal 

Register listings at http://www.epa.gov/ 

fedrgstr/. 

An electronic version of the official 

public docket is available through 

http://www.regulations.gov. You may 

use http://www.regulations.gov to view 

public comments, access the index 

listing of the contents of the official 


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Federal Register / Vol. 75, No. 56 / Wednesday, March 24, 2010 / Rules and Regulations 14261 

1These requirements are found in Clean Air Act 

section 176(c)(B)(i), (ii), and (iii): ‘‘That such 

activities will not cause or contribute to any new 

violation of any standard in any area; increase the 

frequency or severity of any existing violation of 

any standard in any area; or delay timely attainment 

of any standard or any required interim emissions 

reductions or other milestones in any area.’’ 

2 40 CFR 93.102(b)(1) defines PM2.5 and PM10 as 

particles with an aerodynamic diameter less than or 

equal to a nominal 2.5 and 10 micrometers, 

respectively. 

3At this website, click on ‘‘Regulations’’ to find 

all of EPA’s proposed and final rules as well as the 

current transportation conformity regulations. 

4 ‘‘2006 PM2.5 NAAQS’’ refers to the 24-hour PM2.5

NAAQS promulgated in 2006. 

5 ‘‘Interim Transportation Conformity Guidance 

for 2006 PM2.5 Nonattainment Areas,’’ EPA–420–B– 

09–036, November 2009, available on EPA’s Web 

site at: http://www.epa.gov/otaq/stateresources/ 

transconf/policy/420b09036.pdf. 

6Today’s final rule changes the baseline year 

used to demonstrate conformity for the 2006 PM2.5

NAAQS prior to having an adequate or approved 

PM2.5 SIP budget; the interim guidance addressed 

this change. Refer to Section IV. for further 

discussion of the baseline year for conformity 

purposes. 

public docket, and access those 

documents in the public docket that are 

available electronically. Once in the 

system, select ‘‘search,’’ then key in the 

appropriate docket identification 

number. 

Certain types of information will not 

be placed in the electronic public 

docket. Information claimed as CBI and 

other information for which disclosure 

is restricted by statute is not available 

for public viewing in the electronic 

public docket. EPA’s policy is that 

copyrighted material is not placed in the 

electronic public docket but is available 

only in printed, paper form in the 

official public docket. 

To the extent feasible, publicly 

available docket materials will be made 

available in the electronic public 

docket. When a document is selected 

from the index list in EPA Dockets, the 

system will identify whether the 

document is available for viewing in the 

electronic public docket. Although not 

all docket materials may be available 

electronically, you may still access any 

of the publicly available docket 

materials through the docket facility 

identified in the ADDRESSES section. 

EPA intends to provide electronic 

access in the future to all of the publicly 

available docket materials through the 

electronic public docket. 

For additional information about the 

electronic public docket, visit the EPA 

Docket Center homepage at http:// 

www.epa.gov/epahome/dockets.htm. 

II. Background on the Transportation 

Conformity Rule 

A. What Is Transportation Conformity? 

Transportation conformity is required 

under CAA section 176(c) (42 U.S.C. 

7506(c)) to ensure that transportation 

plans, transportation improvement 

programs (TIPs) and federally supported 

highway and transit project activities 

are consistent with (‘‘conform to’’) the 

purpose of the state air quality 

implementation plan (SIP). Conformity 

to the purpose of the SIP means that 

transportation activities will not cause 

new air quality violations, worsen 

existing violations, or delay timely 

attainment of the relevant national 

ambient air quality standards (NAAQS) 

or any interim milestones.1

Transportation conformity applies to 

areas that are designated nonattainment, 

and those areas redesignated to 

attainment after 1990 (‘‘maintenance 

areas’’) for transportation-related criteria 

pollutants: Carbon monoxide (CO), 

ozone, nitrogen dioxide (NO2) and 

particulate matter (PM2.5, and PM10).2

EPA’s transportation conformity rule 

(40 CFR Parts 51 and 93) establishes the 

criteria and procedures for determining 

whether transportation activities 

conform to the SIP. EPA first 

promulgated the transportation 

conformity rule on November 24, 1993 

(58 FR 62188), and subsequently 

published several other amendments. 

DOT is EPA’s federal partner in 

implementing the transportation 

conformity regulation. EPA has 

consulted with DOT, which concurs 

with this final rule. 

A few recent amendments to the 

transportation conformity rule are 

useful background for today’s final rule. 

In a final rule EPA published on July 1, 

2004 (69 FR 40004), EPA provided 

conformity procedures for state and 

local agencies under the 1997 8-hour 

ozone and PM2.5 national ambient air 

quality standards (NAAQS). EPA’s 

nonattainment area designations for the 

1997 8-hour ozone and PM2.5 NAAQS 

were effective in June 2004 and April 

2005, respectively. The July 2004 

update provided rules for implementing 

conformity for these NAAQS. In 

addition, on May 6, 2005, EPA 

promulgated a final rule entitled, 

‘‘Transportation Conformity Rule 

Amendments for the New PM2.5

National Ambient Air Quality Standard: 

PM2.5 Precursors’’ (70 FR 24280). This 

final rule specified transportationrelated PM2.5 precursors and when they 

must be considered in transportation 

conformity determinations in PM2.5

nonattainment and maintenance areas. 

On March 10, 2006, EPA promulgated 

a final rule (71 FR 12468) entitled, 

‘‘PM2.5 and PM10 Hot-Spot Analyses in 

Project-Level Transportation Conformity 

Determinations for the New PM2.5 and 

Existing PM10 National Ambient Air 

Quality Standards.’’ This rule 

established the criteria and procedures 

for determining which transportation 

projects must be analyzed for local air 

quality impacts—or ‘‘hot-spots’’—in 

PM2.5 and PM10 nonattainment and 

maintenance areas. See Section IX. of 

today’s preamble for more information 

regarding the March 2006 rule; see 

EPA’s Web site at http://www.epa.gov/ 

otaq/stateresources/transconf/ 

index.htm for further information about 

any of EPA’s transportation conformity 

rulemakings.3

B. Why Are We Issuing This Final Rule? 

Today’s action is necessary because 

EPA promulgated a final rule on 

October 17, 2006 that changed the PM2.5

and PM10 NAAQS, as described further 

below. Today’s action provides rules for 

implementing conformity for these 

revisions to the PM2.5 and PM10

NAAQS. Sections III. through VIII. 

describe the changes to the 

transportation conformity rule that are a 

result of the October 2006 revisions to 

the PM2.5 and PM10 NAAQS. 

Today’s final rule is the second 

transportation conformity rulemaking 

undertaken primarily for the purpose of 

addressing a new or revised NAAQS. 

Due to other statutory requirements, 

EPA will continue to establish new or 

revised NAAQS in the future. Therefore, 

EPA may consider restructuring certain 

sections of the conformity rule in a 

future rulemaking so that existing rule 

requirements would clearly apply to 

areas designated for future new or 

revised NAAQS, without having to 

update the rule each time a new or 

revised NAAQS is established. 

Note that in 2009, EPA issued an 

interim conformity guidance for areas 

designated nonattainment for the 2006 

PM2.5 NAAQS 4 (‘‘2006 PM2.5 areas’’).5

EPA issued this interim guidance to 

help new nonattainment areas meet 

conformity requirements by the end of 

the one-year grace period. While this 

interim guidance is superseded by 

today’s final rule, conformity 

determinations done according to the 

interim guidance are consistent with the 

CAA, and with the transportation 

conformity rule.6 Therefore, conformity 

determinations based on the interim 

guidance and the transportation 

conformity rule in effect at the time of 

the conformity determination will 

remain valid. Conformity 

determinations completed on or after 

the effective date of this final rule must 

meet all the requirements in the final 

rule. EPA will work with the 2006 PM2.5


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7 ‘‘1997 PM2.5 NAAQS’’ includes both the annual 

and the 24-hour 1997 PM2.5 NAAQS unless noted 

otherwise. 

8A Federal Register notice designating areas for 

the 2006 PM2.5 NAAQS had been signed in late 

December 2008 by then-Administrator Johnson, 

where the designations were based on air quality 

data from 2005–2007. The December 2008 notice 

was awaiting publication in January 2009 when the 

newly elected Administration identified the notice 

as one that should receive additional review before 

publication. However, this notice was never 

published in the Federal Register and, therefore, 

designations were not officially promulgated. CAA 

section 107(d)(2)(A) requires EPA to publish the 

notice in the Federal Register in order to 

promulgate designations. Since January 2009, 

monitoring data for 2008 has become available for 

areas across the U.S. Therefore, the final 

designations in the final rule signed by 

Administrator Jackson on October 8, 2009 are based 

on air quality monitoring data from Federal 

Reference Method monitors for calendar years 

2006–2008. 

9The two areas designated as nonattainment for 

both the annual and 24-hour 1997 PM2.5 NAAQS 

are the Los Angeles-South Coast Air Basin, CA 

nonattainment area and the San Joaquin Valley, CA 

nonattainment area. 

10Clean Air Act section 176(c)(5) and 40 CFR 

93.102(b). 

11EPA began the process of notifying state and 

local agencies, via the EPA regional offices, of the 

timing of conformity under the 2006 PM2.5 NAAQS 

in its April 16, 2007 memorandum entitled, 

‘‘Transportation Conformity and the Revised 24- 

hour PM2.5 Standard,’’ from Merrylin Zaw-Mon, 

Director, Transportation and Regional Programs 

Division, EPA Office of Transportation and Air 

Quality, to EPA Regional Air Directors, Regions 

I–X. 

12See EPA’s July 1, 2004 final rule for further 

background on how EPA has implemented this 

conformity grace period for the 1997 PM2.5 NAAQS 

(69 FR 40004). 

13For the purposes of transportation conformity, 

a ‘‘donut’’ area is the geographic area outside a 

metropolitan planning area boundary, but inside a 

designated nonattainment or maintenance area 

boundary that includes an MPO (40 CFR 93.101). 

For more discussion on how conformity 

determinations should be made for donut areas, see 

the preamble to the July 1, 2004 conformity rule 

(69 FR 40013). 

14 Determining conformity for these other NAAQS 

during the one-year grace period is not necessary 

unless required by 40 CFR 93.104 (for example, a 

new or amended transportation plan and TIP are to 

be adopted). 

15The lapse grace period provision in CAA 

section 176(c)(9) does not apply to the deadline for 

newly designated nonattainment areas to make the 

initial transportation plan/TIP conformity 

determination within 12 months of the effective 

areas to ensure they can meet 

conformity requirements on time. 

Today’s final rule also responds to a 

court decision regarding the March 2006 

hot-spot rulemaking. Section IX. of this 

preamble describes the issue, the court’s 

decision, and EPA’s response. 

III. General Overview of 

Transportation Conformity for the 2006 

PM2.5 NAAQS 

A. Background on 2006 PM2.5 NAAQS 

Development 

EPA issued a final rule on October 17, 

2006, effective December 18, 2006, that 

strengthened the 24-hour PM2.5 NAAQS 

and revoked the annual PM10 NAAQS 

(71 FR 61144). In that final rule, EPA 

strengthened the 24-hour PM2.5 NAAQS 

from the 1997 level of 65 micrograms 

per cubic meter (μg/m3) (average of 98th 

percentile values for three consecutive 

years) to 35 μg/m3, while the level of the 

annual PM2.5 NAAQS remained 

unchanged at 15.0 μg/m3 (average of 

three consecutive annual average 

values). EPA selected levels for the final 

NAAQS after completing an extensive 

review of thousands of scientific studies 

on the impact of fine and coarse 

particles on public health and welfare. 

For additional information about the 

October 17, 2006 rulemaking, the final 

rule and EPA outreach materials can be 

found at: http://www.epa.gov/ 

pmdesignations/. 

The October 2006 rule establishing 

the 2006 PM2.5 NAAQS did not revoke 

the 1997 annual or 24-hour PM2.5

NAAQS. See Section III.D. below for 

details on how today’s final rule 

interacts with conformity requirements 

for those areas designated 

nonattainment for the 1997 PM2.5

NAAQS.7

EPA signed the final rule designating 

areas for the 2006 PM2.5 NAAQS on 

October 8, 2009.8 This final rule was 

published in the Federal Register on 

November 13, 2009, and became 

effective December 14, 2009. The 

designations for the 2006 PM2.5 NAAQS 

are separate from the existing 

designations for the 1997 PM2.5 NAAQS. 

However, in the final rule designating 

areas for the 2006 PM2.5 NAAQS, EPA 

has also clarified that all 39 areas 

designated nonattainment for the 1997 

PM2.5 NAAQS were violating the annual 

PM2.5 NAAQS, and two of those were 

also violating the 24-hour PM2.5

NAAQS.9 That is, EPA’s designations 

rule clarifies that only two areas were 

designated nonattainment for the 1997 

24-hour PM2.5 NAAQS, and that all 39 

nonattainment areas were designated 

nonattainment for the 1997 annual 

PM2.5 NAAQS. 

Transportation conformity applies for 

the NAAQS for which an area is 

designated nonattainment.10 Therefore, 

in two of the 1997 PM2.5 areas, 

conformity applies for both the 1997 

annual and 24-hour NAAQS. In the 

other 37 1997 PM2.5 areas, conformity 

applies for the 1997 annual NAAQS, 

and not the 1997 24-hour PM2.5 NAAQS. 

Refer to EPA’s Web site at: http:// 

www.epa.gov/pmdesignations/ 

2006standards/index.htm for additional 

information about the nonattainment 

designations. 

B. When Does Conformity Apply for the 

2006 PM2.5 NAAQS? 

Transportation conformity for the 

2006 PM2.5 NAAQS does not apply until 

December 14, 2010, which is one year 

after the effective date of nonattainment 

designations for this NAAQS. CAA 

section 176(c)(6) and 40 CFR 93.102(d) 

provide a one-year grace period from the 

effective date of designations before 

transportation conformity applies in 

areas newly designated nonattainment 

for a particular NAAQS.11

The following discussion provides 

more details on the application of the 

one-year grace period in different types 

of newly designated nonattainment 

areas for the 2006 PM2.5 NAAQS. This 

information is consistent with how 

conformity for new NAAQS has been 

implemented in the past.12 The 

conformity grace period will be 

available to all newly designated 

nonattainment areas for the 2006 PM2.5

NAAQS. 

Metropolitan areas are urbanized 

areas that have a population greater than 

50,000 and a designated metropolitan 

planning organization (MPO) 

responsible for transportation planning 

per 23 U.S.C. 134. Within one year after 

the effective date of the initial 

nonattainment designation for the 2006 

PM2.5 NAAQS, a conformity 

determination for this NAAQS must be 

made by the MPO and DOT for the 

MPO’s transportation plan and TIP. 

MPOs must continue to meet conformity 

requirements for any other applicable 

NAAQS, including the 1997 PM2.5

NAAQS, if the area is designated 

nonattainment or maintenance for such 

NAAQS as well. 

In nonattainment and maintenance 

areas with a donut portion,13 adjacent 

MPOs must meet conformity 

requirements for the 2006 PM2.5

NAAQS. The MPO must also continue 

to ensure that conformity is met for any 

other applicable NAAQS, including any 

1997 PM2.5 NAAQS for which the donut 

area is designated nonattainment.14 The 

interagency consultation partners for 

each newly designated nonattainment 

area that includes a donut portion 

should determine how best to consider 

the donut area transportation system 

and new donut area projects in the 

MPO’s regional emissions analyses and 

transportation plan and TIP conformity 

determinations. 

If, at the end of the one-year grace 

period, the MPO and DOT have not 

made a transportation plan and TIP 

conformity determination for the 2006 

PM2.5 NAAQS, the entire area, including 

any donut area, would be in a 

conformity ‘‘lapse.’’ 15 During a 


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date of the nonattainment designation. For 

additional details on the conformity lapse grace 

period, see the preamble to the January 24, 2008 

conformity rule (73 FR 4423–4425). 

16For additional information on projects that can 

proceed during a conformity lapse, refer to the final 

rule of July 1, 2004 (69 FR 40005–40006), which 

addressed the March 2, 1999 U.S. Court of Appeals 

decision that affected related provisions of the 

conformity rule (Environmental Defense Fund v. 

EPA, 167 F.3d 641 (D.C. Cir. 1999). See also the 

following guidance memoranda that address this 

court decision: DOT’s January 2, 2002 guidance, 

published in the Federal Register on February 7, 

2002 (67 FR 5882); DOT’s May 20, 2003 and FTA’s 

April 9, 2003 supplemental guidance documents; 

and, EPA’s May 14, 1999 guidance memorandum. 

17Prior to today’s rulemaking, the requirements 

for isolated rural areas were found at § 93.109(l). 

This section has been renamed as § 93.109(n), as a 

result of other revisions and additions in this 

regulatory section. This is merely an administrative 

change and the conformity requirements for 

isolated rural areas remain unchanged. 

18 Information on 2006 PM2.5 nonattainment 

designations, including copies of EPA’s designation 

letters, can be accessed from EPA’s Web site at 

http://www.epa.gov/pmdesignations/ 

2006standards/state.htm. 

19Memorandum entitled, ‘‘Transportation 

Conformity and the Revised 24-hour PM2.5

Standard,’’ from Merrylin Zaw-Mon, then-Director, 

Transportation and Regional Programs Division, 

EPA Office of Transportation and Air Quality, to 

EPA Regional Air Directors, Regions I– X, found on 

EPA’s Web site at: http://www.epa.gov/otaq/ 

stateresources/transconf/generalinfo/rev24hrpm25.pdf. 

conformity lapse, only certain projects 

can receive additional federal funding 

or approvals to proceed (e.g. exempt 

projects, project phases that were 

approved before the lapse).16 The 

practical impact of a conformity lapse 

will vary on an area-by-area basis. 

The one-year grace period for 

conformity also applies to project-level 

conformity determinations (including 

hot-spot analyses in certain cases) in 

newly designated 2006 PM2.5

nonattainment areas. At the end of the 

one-year grace period for conformity, 

requirements for project-level 

conformity determinations must be met 

for the 2006 PM2.5 NAAQS (including 

hot-spot analyses in certain cases) 

before any new federal approvals for 

such projects can occur. See Table 1 in 

40 CFR 93.109 for the conformity 

criteria that apply for project-level 

conformity determinations. 

Isolated rural nonattainment and 

maintenance areas are areas that do not 

contain or are not part of any 

metropolitan planning area as 

designated by 23 U.S.C. 134 and 49 

U.S.C. 5303 (40 CFR 93.101). As in other 

newly designated nonattainment areas, 

the one-year conformity grace period for 

the 2006 PM2.5 NAAQS will begin on 

the effective date of an isolated rural 

area’s initial nonattainment designation. 

However, because these areas do not 

have federally required metropolitan 

transportation plans and TIPs, they are 

not subject to the frequency 

requirements for conformity 

determinations on transportation plans 

and TIPs (40 CFR 93.104(b),(c), and (e)). 

Instead, conformity determinations in 

isolated rural areas are required only 

when a non-exempt FHWA/FTA 

project(s) needs approval. 

Therefore, although the one-year 

conformity grace period is available to 

isolated rural areas, most likely no 

conformity consequences would occur 

upon the expiration date of the one-year 

grace period because these areas most 

likely would not have any projects that 

require federal funding or approval at 

that time. Once the conformity grace 

period has expired, a conformity 

determination would only be required 

in such areas when a non-exempt 

FHWA/FTA project needs approval. 

Conformity requirements for isolated 

rural areas can be found at 40 CFR 

93.109(n).17

Response to comments about the 

grace period. Some commenters 

believed that the one-year grace period 

would not allow enough time for some 

areas to meet the conformity 

requirements. These same commenters 

questioned whether a year would be 

enough time to adequately prepare 

attainment SIPs, learn EPA’s new 

emissions factor model (called the 

Motor Vehicle Emissions Simulator, or 

MOVES model) when final, and 

complete their conformity 

determinations. To address these 

concerns, these commenters suggested 

lengthening the conformity grace period 

for newly designated nonattainment 

areas from one to two years. 

EPA understands that some areas, 

such as areas that have never done 

conformity before and multijurisdictional nonattainment areas (e.g., 

areas with multiple states and/or 

multiple MPOs) may have additional 

challenges in conducting their initial 

conformity determinations. However, 

the CAA as amended on October 27, 

2000 specifically provides newly 

designated nonattainment areas with 

only a one-year grace period, after 

which conformity applies as a matter of 

law under the statute. Therefore, we 

believe that the statutory language 

precludes EPA from extending the 

conformity grace period beyond one 

year for new nonattainment areas. 

In accordance with the CAA, states 

were initially required to submit their 

recommendations for nonattainment 

areas based on monitored data by 

December 18, 2007, well before 

designations became effective.18

Additionally, EPA began the process of 

notifying state and local agencies, via 

the EPA regional offices, of the timing 

of conformity under the 2006 PM2.5

NAAQS in the April 16, 2007 

memorandum cited earlier.19 As 

mentioned, EPA provided interim 

guidance for the 2006 PM2.5 areas to 

assist in meeting conformity 

requirements by the end of the one-year 

grace period. Finally, EPA will be 

working with 2006 PM2.5 areas to 

provide technical assistance in an 

expeditious manner, such as helping 

each area determine which test applies 

for the first 2006 PM2.5 conformity 

determination. 

We also want to clarify that while 

areas will have to complete a conformity 

determination for their transportation 

plans and TIPs within one year, they are 

not required to complete their 

attainment demonstration SIPs for the 

2006 PM2.5 NAAQS in that same time 

period as the commenter suggested. 

Instead, they will have three years from 

the effective date of designations to 

submit their attainment demonstrations, 

per CAA section 172(b). 

Also, implementers will have 

additional time before MOVES is 

required for conformity determinations, 

as a different grace period will apply for 

MOVES once it is released. The 

conformity rule at 40 CFR 93.111 

provides a grace period before a new 

emissions model is required for 

conformity. This grace period can be 

anywhere from three months to two 

years depending on the degree of change 

from one model to another (40 CFR 

93.111(b)(2)); EPA is intending to 

provide the maximum length two-year 

grace period for the transition to 

MOVES. Therefore, MOVES will not be 

required for the first transportation plan 

and TIP conformity determination done 

for the 2006 PM2.5 NAAQS. EPA will 

provide specific guidance regarding the 

MOVES grace period and when MOVES 

will be required to be used for SIPs and 

conformity. This guidance will be 

available on EPA’s Web site at: http:// 

www.epa.gov/otaq/stateresources/ 

transconf/policy.htm#models. 

EPA and DOT understand the concern 

that the commenter notes with respect 

to learning the new MOVES model, and 

therefore have devoted significant staff 

time and resources to training state and 

local air quality and transportation 

planners in using MOVES. During 2009, 

20 MOVES training sessions were held 

at locations across the U.S. Once 

MOVES is final, EPA intends to offer 

web-based training, and EPA and DOT 

are planning to hold additional inperson training sessions as well. See 

EPA’s Web site: http://www.epa.gov/ 


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20 ‘‘Transportation Conformity Guidance for 

Qualitative Hot-spot Analyses in PM2.5 and PM10

Nonattainment and Maintenance Areas,’’ EPA420– 

B–06–902, March 2006. 

21EPA notes that today’s final rule does not 

address project requirements for the National 

Environmental Policy Act or other environmental 

programs. 

22Note that instead of establishing a budget for 

direct PM2.5 or NOX, a SIP could demonstrate that 

the pollutant or precursor is insignificant based on 

40 CFR 93.109(k). 

otaq/models/moves/ 

trainingsessions.htm for information 

about upcoming training sessions. Also 

note that other MOVES related 

guidance, including user guides and 

other technical information is available 

on EPA’s Web site at: http:// 

www.epa.gov/otaq/models/moves/ 

index.htm and http://www.epa.gov/ 

otaq/stateresources/transconf/ 

policy.htm 

C. Definitions for PM2.5 NAAQS 

EPA is adding two new definitions to 

§ 93.101 of the conformity rule to 

distinguish between the 1997 PM2.5

NAAQS and the 2006 PM2.5 NAAQS. 

These definitions will help implement 

certain conformity requirements in areas 

that have been designated 

nonattainment for 1997 PM2.5 NAAQS 

and/or 2006 PM2.5 NAAQS. Some areas 

designated nonattainment for the 2006 

PM2.5 NAAQS also are designated 

nonattainment for the 1997 PM2.5

NAAQS. In addition, some areas are 

designated for only the 2006 PM2.5

NAAQS. 

These definitions are similar to the 

rule’s definitions in 40 CFR 93.101 for 

the 1-hour ozone NAAQS and 8-hour 

ozone NAAQS, and are generally 

consistent with how EPA is defining 

both kinds of PM2.5 areas for air quality 

planning purposes. EPA also notes that 

any provision of the conformity rule 

that references only ‘‘PM2.5’’ and does 

not specify which PM2.5 NAAQS applies 

to any area designated nonattainment 

for a PM2.5 NAAQS. EPA received no 

comments regarding these definitions. 

D. How Does This Final Rule Interact 

With Conformity Requirements for the 

1997 PM2.5 NAAQS? 

Sections IV. through VI. of today’s 

final rule describe conformity 

requirements for areas designated 

nonattainment for the 2006 PM2.5

NAAQS. No changes have been made to 

the existing transportation conformity 

requirements for areas designated 

nonattainment for the 1997 PM2.5

NAAQS. 

Nonattainment designations for the 

1997 and 2006 PM2.5 NAAQS are 

different designations with separate SIP 

requirements, different attainment 

dates, etc. As a result, CAA section 

176(c)(5) requires conformity 

requirements to be met in both 1997 and 

2006 PM2.5 nonattainment and 

maintenance areas, as applicable. 

Some areas designated nonattainment 

for the 2006 PM2.5 NAAQS have never 

been subject to PM2.5 conformity 

requirements. Under today’s final rule 

and CAA section 176(c)(5), these areas 

must meet conformity requirements 

only for the 2006 PM2.5 NAAQS, and not 

for the 1997 PM2.5 NAAQS, because 

these areas are not designated 

nonattainment for the 1997 PM2.5

NAAQS. 

Other areas designated nonattainment 

for the 2006 PM2.5 NAAQS have been 

designated also, in whole or in part, for 

the 1997 PM2.5 NAAQS. (See Section 

III.A. for the clarification that EPA has 

made in designations for the 1997 PM2.5

NAAQS areas.) These areas must 

continue to meet their existing 

conformity requirements for the 1997 

PM2.5 NAAQS as well as those that 

apply for the 2006 PM2.5 NAAQS. 

One commenter was concerned that, 

given identical boundaries, an area 

could potentially be required to prepare 

conformity determinations for three 

different PM NAAQS (i.e., the 24-hr 

PM10 NAAQS, 1997 PM2.5 NAAQS, and 

2006 PM2.5 NAAQS), and believed that 

this could mean three separate analyses 

would be required. This commenter 

recommended that an area should only 

have to model to the most restrictive 

NAAQS. 

As described in the May 2009 

proposal, nonattainment designations 

for these NAAQS are different 

designations with separate SIP 

requirements, different attainment 

dates, etc. As a result, CAA section 

176(c)(5) requires conformity to be met 

for all of the NAAQS for which an area 

has been designated. However, MPOs 

subject to more than one PM NAAQS 

will be able to use existing 

transportation models and data for 

regional emissions analyses, especially 

where nonattainment area boundaries 

are the same. Some analysis years for 

the regional emissions analyses will be 

the same, such as the last year of the 

transportation plan. In addition, MPOs 

in areas designated for more than one 

PM NAAQS will be able to meet 

consultation and other conformity 

requirements through the existing 

processes. 

Furthermore, if an area is designated 

nonattainment for both the 1997 and 

2006 PM2.5 NAAQS and it has no 

adequate or approved PM2.5 budgets, it 

could use the same interim emissions 

test for both NAAQS (see Section V.; 

note that the baseline year for these two 

NAAQS are different, see Section IV.) If 

such an area has budgets only for the 

1997 PM2.5 NAAQS, conformity 

determinations for the 2006 PM2.5

NAAQS will be based on the same 

conformity test—i.e., the budget test— 

that is being used for the 1997 PM2.5

NAAQS (note that the attainment year 

for each of these NAAQS, which is a 

required analysis year for the budget 

test, will differ). As described in Section 

VI., MPOs must use any adequate or 

approved SIP budgets for the 1997 PM2.5

NAAQS for conformity determinations 

that are made prior to SIP budgets for 

the 2006 PM2.5 NAAQS being found 

adequate or approved. 

Today’s final rule does not impact 

project-level conformity requirements 

for the 1997 PM2.5 NAAQS. For 

example, this rule does not 

substantively change the PM2.5 hot-spot 

analysis requirements, and EPA and 

FHWA’s existing qualitative guidance 

for such analyses continues to be 

available.20 For the purposes of PM2.5

conformity, a hot-spot analysis must 

address the PM2.5 NAAQS for which the 

area has been designated 

nonattainment.21 See Section VII. for 

further information regarding projectlevel conformity requirements for the 

2006 PM2.5 NAAQS. 

EPA will work with PM2.5

nonattainment areas as needed to ensure 

that state and local agencies can meet 

conformity requirements for both the 

applicable 1997 and 2006 PM2.5 NAAQS 

in a timely and efficient manner. 

E. Precursors That Apply for 2006 PM2.5

Conformity 

The existing transportation 

conformity rule at 40 CFR 93.102(b) 

describes the pollutants and precursors 

that must be examined in a regional 

emissions analysis in PM2.5 areas, and 

these provisions apply to 2006 PM2.5

areas as well as 1997 PM2.5 areas. Direct 

PM2.5 must be analyzed per 40 CFR 

93.102(b)(1). Before SIP budgets are 

adequate or approved, NOX must also be 

analyzed, unless both EPA and the state 

air quality agency find that 

transportation-related emissions of NOX

are not a significant contributor to the 

PM2.5 nonattainment problem and notify 

the MPO and DOT (40 CFR 

93.102(b)(iv)).22 Before SIP budgets are 

adequate or approved, VOCs, sulfur 

dioxide, and ammonia do not have to be 

analyzed unless either EPA or the state 

air quality agency finds that such a 

precursor is a significant contributor, 

and notifies the MPO and DOT (40 CFR 

93.102(b)(v)). Similarly, before SIP 

budgets are adequate or approved, road 

dust does not have to be included in the 

regional emission analysis of directly 


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23 40 CFR 51.30(b). 

24See http://www.epa.gov/otaq/stateresources/ 

transconf/index.htm. 

emitted PM2.5 unless EPA or the state air 

agency find that re-entrained road dust 

emissions are a significant contributor, 

and notifies the MPO and DOT (40 CFR 

93.102(b)(3)). 

Once budgets from a submitted PM2.5

SIP have been found adequate or 

approved, a conformity determination 

for the 2006 PM2.5 NAAQS must include 

any precursors for which budgets are 

established (40 CFR 93.102(b)(iv) and 

(v)). If road dust is included in the 

direct PM2.5 budget, it must also be 

included in a regional emissions 

analysis (40 CFR 93.102(b)(3)). 

Please use the interagency 

consultation process if there are 

questions regarding whether a regional 

emissions analysis for the 2006 PM2.5

NAAQS must include specific 

precursors or road dust. 

IV. Baseline Year for Certain 2006 

PM2.5 Nonattainment Areas 

A. Background 

Conformity determinations for 

transportation plans, TIPs, and projects 

not from a conforming transportation 

plan and TIP must include a regional 

emissions analysis that fulfills CAA 

provisions. The conformity rule 

provides for several different regional 

emissions analysis tests that satisfy CAA 

requirements in different situations. 

Once a SIP with a motor vehicle 

emissions budget (‘‘budget’’) is 

submitted for an air quality NAAQS and 

EPA finds the budget adequate for 

conformity purposes or approves it as 

part of the SIP, conformity is 

demonstrated using the budget test for 

that pollutant or precursor, as described 

in 40 CFR 93.118. 

Before an adequate or approved SIP 

budget is available, conformity of the 

transportation plan, TIP, or project not 

from a conforming transportation plan 

and TIP is demonstrated using the 

interim emissions test(s), as described in 

40 CFR 93.119. The interim emissions 

tests include different forms of the 

‘‘build/no-build’’ test and ‘‘baseline year’’ 

test. In general, for the baseline year 

test, emissions from the planned 

transportation system are compared to 

emissions that occurred in the baseline 

year. Today’s rule updates section 

93.119 of the conformity rule for the 

2006 PM2.5 NAAQS. The baseline year 

for nonattainment areas under the 1997 

PM2.5 NAAQS is 2002 (40 CFR 

93.119(e)(2)). Sections V. and VI. of 

today’s final rule go into further detail 

about how the baseline year will be 

applied in 2006 PM2.5 areas. 

B. Baseline Year for 2006 PM2.5 Areas 

1. Description of Final Rule 

In today’s final rule, EPA is defining 

the baseline year as the most recent year 

for which EPA’s Air Emissions 

Reporting Requirements (AERR) (40 

CFR Part 51) requires submission of onroad mobile source emissions 

inventories,23 as of the effective date of 

EPA’s nonattainment designations for 

any PM2.5 NAAQS other than the 1997 

PM2.5 NAAQS. EPA had proposed this 

definition under ‘‘Option 2’’ in the 

proposed rule. AERR requires on-road 

mobile source emission inventories to 

be submitted every three years, for 

example, 2002, 2005, 2008, 2011, etc. 

See § 93.119(e)(2)(B) for the regulatory 

text. 

Today’s final rule results in a baseline 

year of 2008 for the 2006 PM2.5 areas. 

The year 2008 is the most recent year as 

of the effective date of the 2006 PM2.5

designations, December 14, 2009, for 

which AERR requires submission of onroad mobile source emissions 

inventories. In other words, the 

designations were effective on 

December 14, 2009, and the most recent 

year for which an on-road mobile source 

inventory was required as of that date 

was 2008. Therefore, 2008 is the 

baseline year for 2006 PM2.5 areas. 

This final rule would also govern the 

baseline year for conformity purposes 

for any areas designated for a PM2.5

NAAQS that EPA promulgates in the 

future. EPA will clarify the relevant 

baseline year under today’s regulation 

for each such future NAAQS for 

conformity implementers in guidance 

and maintain a list of baseline years that 

result from today’s final rule on EPA’s 

Web site.24

Today’s action does not change the 

2002 baseline year for areas designated 

nonattainment for the 1997 PM2.5

NAAQS and the conformity rule now 

clarifies that 2002 applies as the 

baseline year only to areas designated 

nonattainment for the 1997 PM2.5

NAAQS. The baseline year for 1997 

PM2.5 NAAQS areas is found in 

§ 93.119(e)(2)(A). 

The existing interagency consultation 

process (40 CFR 93.105(c)(1)(i)) must be 

used to determine the latest 

assumptions and models for generating 

baseline year motor vehicle emissions to 

complete any baseline year test. The 

baseline year emissions level that is 

used in conformity must be based on the 

latest planning assumptions available, 

the latest emissions model, and 

appropriate methods for estimating 

travel and speeds as required by 40 CFR 

93.110, 93.111, and 93.122 of the 

current conformity rule. The baseline 

year test can be completed with a 

submitted or draft baseline year motor 

vehicle emissions SIP inventory, if the 

SIP reflects the latest information and 

models. If such a SIP baseline is not 

available, an MPO, in consultation with 

state and local air agencies, could also 

develop baseline year emissions as part 

of the conformity analysis. 

2. Rationale and Response to Comments 

General overview. EPA believes that 

today’s definition for the baseline year 

results in an environmentally protective 

and legal baseline year for conformity 

under the 2006 PM2.5 NAAQS and any 

future PM2.5 NAAQS revisions, and best 

accomplishes several important goals. 

First, as EPA discussed in the 

preamble to the proposed rule, EPA 

believes that a more recent year than 

2002 (the baseline year for 1997 PM2.5

areas) is appropriate for meeting CAA 

conformity requirements for 2006 PM2.5

nonattainment areas. EPA also believes 

that using a more recent year is more 

environmentally protective than 2002, 

and more relevant for the 2006 PM2.5

NAAQS. Several commenters agreed 

with these points. Because the AERR 

requires submission of inventories every 

three years, today’s final rule results in 

a baseline year that is recent for any 

PM2.5 NAAQS established after 1997. 

The baseline year will always be either 

the same year as the year in which 

designations are effective, or one or two 

years prior to the effective date of 

designations. For example, in the case of 

the 2006 PM2.5 NAAQS, the baseline 

year, 2008, is the year before the year in 

which designations are effective, 2009. 

EPA had also proposed 2005 as a 

baseline year as it is also more recent 

than 2002. One commenter preferred a 

2005 baseline year because the 

introduction of Tier 2 and improved 

fuel and engine technologies since then 

would allow transportation plans and 

TIPs to meet conformity more easily. 

However, because of the 

implementation of EPA’s Tier 2 Vehicle 

and Gasoline Program as well as other 

federal programs, motor vehicle 

emissions in the year 2005 were higher 

than emissions in the year 2008. Thus 

today’s rule, which results in a baseline 

year of 2008, provides more protection 

for the environment than would a 

baseline year of 2005, in the time before 

an area has adequate or approved motor 

vehicle emissions budgets from a SIP 

that addresses PM2.5. 

Second, today’s baseline year 

definition coordinates the conformity 


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baseline year with other air quality 

planning requirements, which allows 

state and local governments to use their 

resources more efficiently. Coordinating 

the conformity baseline year with the 

year used for SIP planning and an 

emission inventory year was EPA’s 

rationale for using 2002 as the baseline 

year for conformity tests in existing 

PM2.5 nonattainment areas for the 1997 

NAAQS. Today’s regulatory text results 

in a conformity baseline year that is 

consistent with emission inventory 

requirements, and most likely will be 

consistent with the baseline year used 

for SIP planning as well. Several 

commenters voiced support for 

coordinating the conformity baseline 

year with these other air quality 

planning requirements. 

Third, today’s final rule provides 

transportation planners with knowledge 

of the baseline year for any future PM2.5

NAAQS upon the effective date of 

designations for that NAAQS, without 

having to wait either for EPA to amend 

the transportation conformity rule or 

select a SIP planning baseline year. As 

a result, MPOs and other transportation 

planners would understand conformity 

requirements for future PM2.5 NAAQS 

revisions more quickly, which may, in 

turn, also allow more time to prepare 

and complete necessary conformity 

determinations. Several commenters 

agreed that not having to wait for a rule 

revision would be a benefit of defining 

the baseline year as in today’s rule, 

rather than choosing a specific year. 

Some commenters preferred defining 

the baseline year in terms of the year 

used as the baseline year for SIP 

planning. Today’s final rule addresses 

these concerns since it will most likely 

result in a conformity baseline year that 

is consistent with the SIP baseline year, 

and in the future will give 

transportation planners the advantage of 

knowing the baseline year at the 

beginning of the grace period for newly 

designated areas. 

Last, given that the CAA requires EPA 

to review the NAAQS for possible 

revision once every five years, today’s 

baseline year provision potentially 

reduces the need for future rule 

revisions for any future PM2.5 NAAQS. 

While today’s final rule establishes a 

baseline year for any PM2.5 NAAQS 

other than the 1997 PM2.5 NAAQS, the 

same rationale would apply for 

establishing the same type of baseline 

year definition for any future new or 

revised NAAQS of a transportationrelated criteria pollutant. Therefore, 

EPA may amend the rule in the future 

to apply the baseline year language 

found in today’s § 93.119(e)(2)(B) more 

generally. However, EPA did not 

propose such an amendment, and 

intends to solicit and consider public 

comment before it would adopt any 

such provision. 

Specific comments. EPA is 

responding today to several comments 

regarding the baseline year. A couple of 

commenters indicated that they thought 

proposed Option 2 would create a 

‘‘rolling’’ baseline year, that is, one that 

would be updated every three years. 

One commenter did not support such a 

rolling baseline; another did support it 

as long as motor vehicle emissions in an 

inventory year were less than the prior 

reporting year. However, today’s final 

rule does not establish a rolling baseline 

year for any PM2.5 NAAQS. It 

establishes a single baseline year for 

each PM2.5 NAAQS that does not change 

over time. For example, for the 2006 

PM2.5 NAAQS, the definition results in 

a baseline year of 2008. The year 2008 

will remain the baseline year for 2006 

PM2.5 areas until it’s no longer needed, 

i.e., until adequate or approved budgets 

are available in a given area. 

One commenter who supported the 

option finalized in today’s rule 

expressed concern that final emissions 

data would not be available for 2008 for 

some time. However, if a final AERR 

inventory for 2008 is not available in a 

particular area, there are other options 

for generating the motor vehicle 

emissions in the baseline year, 

discussed above under ‘‘IV.B.1. 

Description of Final Rule.’’ 

Another commenter expressed 

concern that MOVES would not be 

available in time for the year 2008 for 

the first conformity determination for 

the 2006 PM2.5 NAAQS. At this time, 

the current emissions model, 

MOBILE6.2, applies for conformity in 

all areas except California, where 

EMFAC2007 applies. Therefore, if the 

MOVES model is not available to 

generate a 2008 baseline estimate for use 

in conformity, the MOBILE6.2 model 

must be used. Once MOVES is available, 

areas can create a new baseline 

emissions estimate for use in conformity 

using MOVES along with other interim 

analysis years. EPA will provide a 

policy guidance document for using 

MOVES in conformity determinations 

that will include more details about 

when MOVES must be used. When 

available, this guidance will be found 

on EPA’s Web site at: http:// 

www.epa.gov/otaq/stateresources/ 

transconf/policy.htm#models. For more 

information on MOVES, please see 

EPA’s Web site at: http://www.epa.gov/ 

otaq/models/moves/index.htm. 

One commenter thought that the 

baseline year should be determined 

through interagency consultation. This 

was not a proposed option. However, 

EPA believes that details for the 

baseline year test must be determined 

through rulemaking, as EPA has done 

for other NAAQS since 1993. Today’s 

rule better accomplishes the purposes of 

meeting the CAA’s requirements, 

coordinating with SIP and inventory 

planning, and providing certainty to 

transportation planners. Furthermore, 

today’s rule ensures consistency across 

the nation, whereas allowing each area 

to determine its own baseline year 

through interagency consultation could 

result in different baseline years in 

different areas. 

V. Regional Conformity Tests in 2006 

PM2.5 Nonattainment Areas That Do 

Not Have Adequate or Approved SIP 

Budgets for the 1997 PM2.5 NAAQS 

This section of the preamble discusses 

regional conformity tests for 

nonattainment areas for the 2006 PM2.5

NAAQS that do not have adequate or 

approved PM2.5 SIP budgets for the 1997 

NAAQS. This part of the final rule 

applies to 2006 PM2.5 nonattainment 

areas that were not covered by the 1997 

PM2.5 NAAQS, as well as nonattainment 

areas for both PM2.5 NAAQS that do not 

have an adequate or approved 1997 

PM2.5 SIP budget. EPA has addressed 

conformity tests for these areas under 

section 93.109(j) of the conformity rule. 

See Section VI. of today’s final rule for 

conformity tests in 2006 PM2.5 areas that 

have adequate or approved SIP budgets 

for the 1997 PM2.5 NAAQS. 

Note that the rule finalizes new 

requirements for conformity only under 

the 2006 PM2.5 NAAQS. Today’s final 

rule does not address or change the 

requirements for demonstrating 

conformity for the 1997 PM2.5 NAAQS. 

A. Conformity After 2006 PM2.5 SIP 

Budgets Are Adequate or Approved 

1. Description of Final Rule 

Once a SIP for the 2006 PM2.5 NAAQS 

is submitted with a budget(s) that EPA 

has found adequate or approved, the 

budget test must be used in accordance 

with 40 CFR 93.118 to complete all 

applicable regional emissions analyses 

for the 2006 PM2.5 NAAQS. This 

requirement is found at § 93.109(j)(2). 

Conformity is demonstrated if the 

transportation system emissions 

reflecting the proposed transportation 

plan, TIP, or project not from a 

conforming transportation plan and TIP 

are less than or equal to the motor 

vehicle emissions budget level defined 

by the SIP as being consistent with CAA 

requirements. 

The first SIP for the 2006 PM2.5

NAAQS could be a control strategy SIP 


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25These areas include ozone areas classified as 

moderate and above, CO areas classified as 

moderate with design value greater than 12.7 ppm, 

and CO areas classified as serious. 

required by the CAA (i.e., reasonable 

further progress SIP or attainment 

demonstration) or a maintenance plan. 

States could also voluntarily choose to 

submit an ‘‘early progress SIP’’ prior to 

required SIP submissions. Early 

progress SIPs must demonstrate a 

significant level of future emissions 

reductions from a previous year’s 

emissions. For example, an area could 

submit an early progress SIP for the 

2006 PM2.5 NAAQS that demonstrates a 

specific percentage of emissions 

reductions (e.g. 5–10%) in an area’s 

attainment year from the baseline year 

emissions (e.g., 2008). An early progress 

SIP would include emissions 

inventories for all emissions sources for 

the entire 2006 PM2.5 nonattainment 

area and would meet applicable 

requirements for reasonable further 

progress SIPs. EPA has discussed this 

option in past conformity rule 

preambles, e.g. the July 1, 2004 

transportation conformity final rule (69 

FR 40028), and many states have 

established early progress SIP budgets 

for conformity purposes. 

Whatever the case, the interim 

emissions test(s) would no longer be 

used for direct PM2.5 or a relevant 

precursor once an adequate or approved 

SIP budget for the 2006 PM2.5 NAAQS 

is established and effective for the 

pollutant or precursor. States are 

required to develop their future 2006 

PM2.5 SIPs in consultation with MPOs, 

state and local transportation agencies, 

and local air quality agencies in an 

effort to facilitate future conformity 

determinations. EPA Regions will be 

available to assist states in the 

development of early progress SIPs for 

the 2006 PM2.5 NAAQS, if desired. 

2. Rationale and Response to Comments 

EPA believes that this provision meets 

statutory requirements for conformity 

determinations that occur after SIP 

budgets are available for the 2006 PM2.5

NAAQS. Section 176(c) of the CAA 

states that transportation activities must 

‘‘conform to an implementation plan...’’ 

(SIP) and states further that conformity 

to an implementation plan means 

conformity to the SIP’s purpose. Once 

EPA finds a budget for the 2006 PM2.5

NAAQS adequate or approves the SIP 

that includes it, the budget test provides 

the best means to determine whether 

transportation plans and TIPs meet the 

statutory obligations in CAA sections 

176(c)(1)(A) and (B) for that NAAQS. 

That is, the budget test best shows that 

transportation plans and TIPs conform 

to the SIP’s purpose of eliminating or 

reducing the severity and number of 

violations of the NAAQS and achieving 

expeditious attainment of the NAAQS 

(176(c)(1)(A)); and best confirms the 

requirement that transportation plans 

and TIPs not cause or contribute to any 

new violation, worsen an existing 

violation, or delay timely attainment or 

any interim milestones (176(c)(1)(B)). 

The budget test also best demonstrates 

that transportation plans and TIPs 

comply with the statutory obligation to 

be consistent with the emissions 

estimates in SIPs, according to CAA 

section 176(c)(2)(A). By being consistent 

with the on-road mobile source 

emissions levels in the SIP, 

transportation planners can ensure that 

their activities remain consistent with 

state and local air quality goals to 

protect public health. EPA received no 

comments on this aspect of today’s rule. 

B. Conformity Before 2006 PM2.5 SIP 

Budgets Are Adequate or Approved 

1. Description of Final Rule 

The 2006 PM2.5 nonattainment areas 

that do not have existing adequate or 

approved PM2.5 budgets for the 1997 

PM2.5 NAAQS must meet one of the 

following interim emissions tests for 

conformity determinations conducted 

before adequate or approved 2006 24- 

hour PM2.5 SIP budgets are established: 

• The build-no-greater-than-no-build 

test (‘‘build/no-build test’’), or 

• The no-greater-than-baseline year 

emissions test (‘‘baseline year test’’). 

This aspect of today’s final rule is 

similar to the transportation conformity 

rule at 40 CFR 93.119(e) for 

nonattainment areas for the 1997 PM2.5

NAAQS. Today’s final rule allows 2006 

PM2.5 nonattainment areas without SIP 

budgets to choose between the two 

interim emissions tests, rather than 

require that one specific test or both 

tests be completed. Conformity is 

demonstrated if, for each analysis year, 

the transportation emissions reflecting 

the proposed transportation plan or TIP 

(build) are less than or equal to either 

the emissions from the existing 

transportation system (no-build), or the 

level of motor vehicle emissions in the 

baseline year, as described in 40 CFR 

93.119. For the discussion of the 

baseline year for the 2006 PM2.5

NAAQS, please refer to Section IV. of 

today’s notice. 

2. Rationale and Response to Comments 

EPA believes that this provision of 

today’s rule meets statutory 

requirements for conformity 

determinations that occur before SIP 

budgets are available for the 2006 PM2.5

NAAQS. EPA believes it is appropriate 

to provide flexibility and allow 2006 

PM2.5 areas to meet only one interim 

emissions test before adequate or 

approved PM2.5 SIP budgets are 

established. 

Using either the build/no-build test or 

baseline year test is sufficient to meet 

CAA section 176(c)(1)(B) requirements 

that transportation activities do not 

cause or contribute to new air quality 

violations, worsen existing violations, or 

delay timely attainment or any interim 

milestones. The baseline year and the 

build/no-build tests are sufficient for 

demonstrating conformity when an area 

does not have a SIP budget for a portion 

of a nonattainment area. 

Based on the CAA, EPA has 

previously determined that only in 

ozone and CO areas of higher 

classifications 25 are transportation 

plans and TIPs required to also satisfy 

section 176(c)(3)(A)(iii), i.e., that the 

transportation plan and TIP contribute 

to emissions reductions, during the time 

period before adequate or approved SIP 

budgets are available (58 FR 3782–3783; 

62 FR 43784–43785; 69 FR 40018, 

40019–40031). As a result, the current 

rule requires these ozone and CO areas 

to meet both interim emissions tests, 

rather than only one test. 

However, prior to today’s rule, the 

conformity rule already allowed areas 

designated for the other pollutants, as 

well as the lower classifications of 

ozone and CO, to conform based on only 

one interim emissions test, rather than 

having to complete two tests and 

thereby contribute further reductions 

towards attainment. Today’s final rule 

requiring the 2006 PM2.5 areas also to 

meet only one of the interim emissions 

tests meets the CAA’s requirements in 

section 176(c)(1)(B) (described above in 

Section II.A., footnote 1). For more 

information and the full rationale for 

allowing some areas to conform based 

on only one interim emissions test, see 

the November 24, 1993 final rule (58 FR 

62197) that addressed interim 

requirements for PM10 and NO2 areas, 

the July 1, 2004 final rule (69 FR 40029) 

that established interim requirements 

for 1997 PM2.5 areas, and the May 15, 

2009 proposed rule. 

EPA believes that the no-greater-thanbaseline year interim emissions test is 

an appropriate test for meeting section 

176(c)(1)(B) (refer to footnote 1 in 

Section II.A.) requirements in 2006 

PM2.5 nonattainment areas. By 

definition, the no-greater-than baseline 

year test ensures that emissions from 

on-road mobile sources are no greater 

than they were during the baseline year 

that will most likely be used for 2006 


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14268 Federal Register / Vol. 75, No. 56 / Wednesday, March 24, 2010 / Rules and Regulations 

26Petitioners challenged several aspects of the 

conformity regulations. In its decision, the U.S. 

Court of Appeals for the District of Columbia 

Circuit upheld EPA’s regulations at 40 CFR 

93.119(b)(2), (d), and (e) ‘‘because the Act does not 

require that activities involving transportation 

actually reduce pollutants, but merely not frustrate 

an implementation plan’s purpose to reduce overall 

emissions.’’ The court also upheld EPA’s regulations 

at 40 CFR 93.118(b), (d), and (e)(6). The court 

vacated a narrow provision at 40 CFR 

93.109(e)(2)(v) which had allowed 8-hour ozone 

areas to avoid using their existing 1-hour budgets 

under certain circumstances. This provision was 

removed from the transportation conformity 

regulation in the January 24, 2008 final rule (see 73 

FR 4434). 

27There are two areas where conformity for both 

the 1997 annual and 24-hour NAAQS applies. See 

Section III.A. for more information. 

28Areas in California should use the interagency 

consultation process to determine appropriate 

methods. In all other 2006 PM2.5 areas, EPA expects 

that MOBILE6.2 will be used for the first 2006 PM2.5

conformity determinations. 

29This description reflects how analyses are to be 

done for the 1997 PM2.5 NAAQS, which is covered 

in ‘‘Guidance for Creating Annual On-Road Mobile 

Source Emission Inventories for PM2.5

Nonattainment Areas for Use in SIPs and 

Conformity,’’ EPA420–B–05–008, August 2005, 

found on EPA’s Web site at: http://www.epa.gov/ 

otaq/stateresources/transconf/policy/ 

420b05008.pdf. In particular, Question 7 on pp. 

5–8 of that guidance addresses how analyses are to 

be done for the 1997 PM2.5 NAAQS. 

30 If a 24-hour emissions estimate is available in 

the appropriate season or month because this step 

has been completed for 1997 PM2.5 NAAQS 

conformity and conformity is being determined for 

the 1997 PM2.5 NAAQS and the 2006 PM2.5 NAAQS 

at the same time, it does not need to be redone but 

can be applied in the regional emissions analysis 

for 2006 PM2.5 conformity. 

31Note that this guidance regarding the choice of 

season applies only when using MOBILE6.2 and not 

MOVES because MOBILE6.2 PM2.5 emission factors 

are not sensitive to changes in temperature. EPA 

will provide guidance on this issue when MOVES 

is released. See EPA’s Web site at: http:// 

www.epa.gov/otaq/models/moves/index.htm and 

http://www.epa.gov/otaq/stateresources/transconf/ 

policy.htm for future MOVES guidance. 

PM2.5 NAAQS SIP planning purposes. If 

future on-road emissions do not 

increase above their base year levels, 

applicable statutory requirements are 

met. 

The build/no-build test also allows a 

2006 PM2.5 area to meet statutory 

requirements. As described above, the 

build/no-build test requires a regional 

emissions analysis to demonstrate that 

the emissions from the proposed 

transportation system in future years 

would be less than the emissions from 

the built transportation system in future 

years. Since for each analysis year, a 

new transportation plan, TIP, or project 

(the build scenario) could not result in 

regional emissions that are higher than 

those that would occur in the absence 

of the proposed transportation activities 

(the no-build scenario) for the system, 

CAA section 176(c)(1)(B) requirements 

are met. For these reasons, EPA believes 

that the build/no-build test continues to 

be an appropriate interim test prior to 

SIP budgets being available. 

Most commenters supported allowing 

2006 PM2.5 areas to meet only one of the 

interim emissions tests because it would 

give areas the flexibility to use the test 

they deem most appropriate, given the 

available data and the unique 

circumstances of individual areas. 

However, one commenter objected, 

arguing that the rule doesn’t promote 

the CAA or the SIP process because it 

doesn’t require reduction of PM2.5

emissions. The commenter also stated 

that the case EPA cited in its proposal, 

Environmental Defense v. EPA 467 F .3d 

1329 (DC Cir. 2006), is not pertinent 

because it did not consider climate 

change factors in any way. 

EPA disagrees. First, it has already 

been clearly established in case law that 

the conformity provisions of the CAA 

do not require that transportation 

projects achieve additional emission 

reductions in PM2.5 areas before SIP 

budgets are available. As discussed 

above, allowing 2006 PM2.5 areas the 

choice of interim emissions tests does 

meet the CAA’s requirements. Today’s 

rule is parallel to the current rule’s 

requirements for 1997 PM2.5

nonattainment areas (69 FR 40028– 

40031), which were upheld by an 

October 2006 court decision. 

Environmental Defense v. EPA, 467 F.3d 

1329 (D.C. Cir. 2006).26 Contrary to the 

commenter’s view, this court case is not 

rendered irrelevant because it doesn’t 

consider climate change factors; 

conformity applies only to 

nonattainment and maintenance areas 

for transportation-related criteria 

pollutants and their precursors. 

The same commenter thought that the 

2006 court case does not preclude EPA 

from reasonably determining that more 

stringent interim rules are required to 

‘‘conform to a SIP’s purpose of reducing 

overall emissions.’’ However, EPA 

believes that the best interpretation of 

the Act is that reflected in today’s rule, 

which allows 2006 PM2.5 areas the 

choice between the interim emissions 

tests. This interpretation is also 

consistent with past rulemakings for 

interim emissions test requirements for 

other pollutants, as described above. 

Finally, one commenter asked EPA to 

clarify whether an area that is currently 

using one of the interim emissions tests 

for the 1997 PM2.5 NAAQS could use 

the results of that test for the 2006 PM2.5

NAAQS. When areas are determining 

conformity for the 1997 and 2006 PM2.5

NAAQS at the same time, they could 

apply some of the information 

developed in the 1997 PM2.5 regional 

emissions analysis in creating 2006 

PM2.5 regional emissions analysis. 

First, note that regardless of whether 

the area is using the baseline year test 

or build/no-build test, the same analysis 

years can be used for 1997 PM2.5

conformity and 2006 PM2.5 conformity 

when the analyses are done at the same 

time (refer to 40 CFR 93.119(g) for 

analysis year requirements). 

In most 1997 PM2.5 areas, conformity 

applies only for the annual NAAQS.27

While the results of an interim 

emissions test for the 1997 annual PM2.5

NAAQS cannot be directly applied for 

the 2006 24-hour PM2.5 NAAQS, the 

option described below could save 

implementers some effort when 

conformity is being determined for both 

of these NAAQS at the same time. This 

option applies only when using 

MOBILE6.2 for regional emissions 

analyses.28

Areas should develop the annual 

emissions for the 1997 PM2.5 NAAQS by 

estimating emissions in two seasons, 

summer and winter; four seasons; or the 

12 months of the year.29

To apply information from the 

analysis done for the 1997 PM2.5

NAAQS to the 2006 PM2.5 analysis, for 

each analysis year, areas should use the 

emission factors developed in the 1997 

PM2.5 NAAQS regional emissions 

analysis for PM2.5 and NOX in a season 

or month where violations of the 2006 

PM2.5 NAAQS occurred, and multiply 

these emission factors by the seasonallyadjusted average daily VMT for the area 

of the analysis year.30 If violations 

occurred in more than one season or 

month, the interagency consultation 

process should be used to choose the 

season or month that would best ensure 

that the CAA is met, for example by 

choosing the season with the most 

frequent or most severe violations, or 

the season with the highest vehicle 

miles traveled, or both.31 The choice of 

season or seasons should be based on air 

quality data from the three years used to 

make designations (i.e., 2006–2008), 

unless more recent air quality data 

indicates that a different season should 

be analyzed, as decided through 

consultation. 

Whatever season is chosen to estimate 

the build scenario emissions, the same 

season should be used for comparison 

whether using the baseline year test or 

build/no-build test. For example, 

emissions for a build scenario 

calculated using winter MOBILE6.2 

inputs should be compared to emissions 

in the winter of the baseline year, or 

emissions in winter from the no-build 

scenario. 


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32Refer to 40 CFR 93.102(b) for which precursors 

apply. To date, before they have adequate or 

approved budgets from a PM2.5 SIP, PM2.5 areas 

have determined conformity for only direct PM2.5

and NOX. 

33 In California where EMFAC is used, areas 

should use the interagency consultation process to 

determine appropriate methods. 

34Note that this guidance regarding the choice of 

season applies only when using MOBILE6.2 and not 

MOVES because MOBILE6.2 PM2.5 emission factors 

are not sensitive to changes in temperature. EPA 

will provide guidance on this issue when MOVES 

is released. See EPA’s Web site at: http:// 

www.epa.gov/otaq/models/moves/index.htm and 

http://www.epa.gov/otaq/stateresources/transconf/ 

policy.htm for future MOVES guidance. 

35Specifically, see EPA’s ‘‘Technical Guidance on 

the Use of MOBILE6.2 for Emission Inventory 

Preparation,’’ EPA420–R–04–013, August 2004, 

found on EPA’s Web site at: http://www.epa. 

gov/otaq/models/mobile6/420r04013.pdf and 

‘‘Procedures for Emission Inventory Preparation— 

Vol IV: Mobile Sources,’’ found at: http://ntl.bts.gov/ 

DOCS/AQP.html. 

Note that after the effective date of 

today’s final rule, the baseline year for 

the 2006 PM2.5 NAAQS will be 2008 

while the baseline year for the 1997 

PM2.5 NAAQS remains 2002. See 

Section IV. for additional discussion of 

the baseline year. 

As stated above, once an area has 

adequate or approved budgets for any 

PM2.5 NAAQS, it must use the budget 

test instead of an interim emissions test. 

C. Implementation of Regional Tests 

The existing conformity rule’s general 

requirements for PM2.5 regional 

emissions analyses apply to 2006 PM2.5

areas that do not have adequate or 

approved SIP budgets for the 1997 PM2.5

NAAQS. EPA is including this 

discussion of the existing regulation’s 

requirements for clarity, to help readers 

understand how the existing regulation 

applies to areas designated 

nonattainment for the 2006 PM2.5

NAAQS. The discussion below is 

intended to illustrate how today’s final 

rule is to be implemented in practice for 

2006 PM2.5 areas without adequate or 

approved 1997 PM2.5 SIP budgets. 

1. Decisions Made Through the 

Interagency Consultation Process 

The existing rule’s consultation 

process must be used to determine the 

test for completing any regional 

emissions analysis for the 2006 PM2.5

NAAQS, as required by 40 CFR 

93.105(c)(1)(i). The existing interagency 

consultation process must also be used 

to determine the latest assumptions and 

models for generating motor vehicle 

emissions regardless of the test used. 

Refer to Section IV. of this preamble for 

details about generating baseline year 

emissions if that interim emissions test 

is selected for a given conformity 

determination. 

In addition, the consultation process 

must be used to determine which 

analysis years should be selected for 

regional emissions analyses. Before an 

adequate or approved 2006 PM2.5 budget 

is available, areas would be able to 

choose, through interagency 

consultation, either interim emissions 

test for each conformity determination. 

However, the same test must be used for 

each analysis year for a given 

determination. EPA believes that 

sufficient flexibility exists without 

mixing and matching interim emissions 

tests for different analysis years within 

one conformity determination, which is 

unnecessarily complicated and may 

indicate that an area would not conform 

using one test consistently. 

2. How a Regional Emissions Analysis 

Can Be Developed When Using An 

Interim Emissions Test 

Under the ‘‘Rationale and Response to 

Comments’’ above, EPA described how 

an area using an interim emissions test 

for 1997 PM2.5 conformity could apply 

it to 2006 PM2.5 conformity. This section 

provides general guidance for creating a 

2006 PM2.5 regional emissions analysis. 

Because the 2006 PM2.5 NAAQS 

designations were only for the 2006 

24-hour PM2.5 NAAQS, the regional 

emissions analysis will be based on 

emissions for a 24-hour time period. 

For either the baseline year test or the 

build/no-build test, for each analysis 

year, emissions must be estimated for 

the build scenario according to 40 CFR 

93.119(i) with a 24-hour emissions 

inventory. (The build scenario is 

referred to as the ‘‘Action’’ scenario at 40 

CFR 93.119(i).) 

This emissions inventory would 

include direct PM2.5, NOX, and any 

other relevant precursor emissions 32

that result from the build scenario using 

MOBILE6.2 for a 24-hour period. For 

each analysis year chosen, areas should 

choose MOBILE6.2 inputs for the season 

of the year where violations of the 2006 

PM2.5 NAAQS occurred.33 If violations 

occurred in more than one season, 

implementers should use the 

interagency consultation process to 

choose the season (or seasons) that 

would best ensure that the CAA is met, 

for example by choosing the season with 

the most frequent or most severe 

violations, or the season with the 

highest vehicle miles traveled, or 

both.34 The choice of season or seasons 

should be based on air quality data from 

the three years used to make 

designations (i.e., 2006–2008), unless 

more recent air quality data indicates 

that a different season should be 

analyzed, as decided through 

consultation. 

For each analysis year, these emission 

factors from MOBILE6.2 for direct PM2.5, 

NOX, and any other relevant precursor 

for the season chosen should be 

multiplied by the seasonally-adjusted 

average daily VMT in that analysis year 

to create an estimate of transportation 

emissions in a 24-hour period. For 

additional guidance on creating daily 

emissions inventories, refer to EPA’s 

existing guidance documents.35

Note that whatever season is chosen 

to estimate the build scenario emissions, 

the same season should be used for 

comparison whether using the baseline 

year test or build/no-build test. For 

example, emissions for a build scenario 

calculated using winter MOBILE6.2 

inputs should be compared to emissions 

in the winter of the baseline year (see 

Section IV. for a discussion of the 

baseline year in 2006 PM2.5 areas), or 

emissions in winter from the no-build 

scenario. 

Refer to 40 CFR 93.119 for additional 

information about conducting the build/ 

no-build and baseline year tests. 

3. Conformity Test Requirements for All 

Areas 

Regional emissions analyses under 

today’s final rule are to be implemented 

through existing conformity 

requirements such as 40 CFR 93.118, 

93.119, and 93.122. For example, the 

existing conformity rule requires that 

certain years within the transportation 

plan (or alternate timeframe) be 

examined. Under 40 CFR 93.118(d), the 

following years would be analyzed for 

the budget test with 2006 PM2.5 SIP 

budgets: 

• The attainment year for the 2006 

PM2.5 NAAQS (if it is within the 

timeframe of the transportation plan and 

conformity determination); 

• The last year of the timeframe of the 

conformity determination (40 CFR 

93.106(d)); and 

• Intermediate years as necessary so 

that analysis years are no more than ten 

years apart. 

For the interim emissions tests, the 

existing conformity rule (40 CFR 

93.119(g)) requires the following 

analysis years: 

• A year no more than five years 

beyond the year in which the 

conformity determination is being 

made; 

• The last year of the timeframe of the 

conformity determination (as described 

in 40 CFR 93.106(d)); 

• Intermediate years as necessary so 

that analysis years are no more than 10 

years apart. 


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36 ‘‘Companion Guidance for the July 1, 2004, 

Final Transportation Conformity Rule: Conformity 

Implementation in Multi-Jurisdictional 

Nonattainment and Maintenance Areas for Existing 

and New Air Quality Standard,’’ EPA420–B–04– 

012, July 2004, found on EPA’s Web site at 

http://www.epa.gov/otaq/stateresources/transconf/ 

policy/420b04012.pdf. 

See the relevant regulatory sections of 

the conformity rule and the July 1, 2004 

final rule preamble for further 

background on how tests have been 

implemented for other pollutants and 

NAAQS (69 FR 40020). 

4. Cases Involving Multi-Jurisdictional 

Areas 

In July 2004, EPA issued a guidance 

document for implementing conformity 

requirements in multi-jurisdictional 

areas.36 Multi-jurisdictional areas are 

nonattainment and maintenance areas 

with multiple MPOs, one or more MPOs 

and a donut area, or multi-state areas. 

EPA believes that this guidance should 

also apply to 2006 PM2.5 areas with 

multiple jurisdictions. 

There are two parts of this existing 

guidance that are most relevant for 

implementing conformity for multijurisdictional 2006 PM2.5 areas that do 

not have adequate or approved 1997 

PM2.5 SIP budgets. Part 2 of this 

guidance describes how conformity 

would be implemented in all 2006 PM2.5

areas before adequate or approved SIP 

budgets are available for an applicable 

NAAQS. Part 3 of this guidance is 

relevant for meeting conformity 

requirements once adequate or 

approved 2006 PM2.5 SIP budgets are 

available. 

For example, Part 3 of this guidance 

describes how a state or MPO in a multistate nonattainment area can operate 

independently from other states/MPOs 

for conformity purposes once adequate 

or approved SIP budgets for a state are 

established. This same conformity 

guidance also applies for the 2006 PM2.5

NAAQS in these types of areas. Part 3 

applies to the cases where subarea 

budgets are established for a 

nonattainment area within one state 

with multiple MPOs. For further 

information, please refer to EPA’s 2004 

multi-jurisdictional conformity 

guidance. 

VI. Regional Conformity Tests in 2006 

PM2.5 Areas That Have Adequate or 

Approved 1997 PM2.5 SIP Budgets 

This section describes the conformity 

tests required for completing regional 

emissions analyses in areas designated 

for the 2006 PM2.5 NAAQS that have 

adequate or approved SIP budgets for 

the 1997 PM2.5 NAAQS that cover either 

part or all of the 2006 PM2.5 area. The 

conformity tests for these areas are 

found under a new section 93.109(k). 

See Section V. of this preamble for 

conformity tests in 2006 PM2.5 areas that 

do not have an adequate or approved 

1997 PM2.5 SIP budget. 

A. Conformity After 2006 PM2.5 SIP 

Budgets Are Adequate or Approved 

1. Description of Final Rule 

Once a SIP for the 2006 PM2.5 NAAQS 

is submitted with budget(s) that EPA 

has found adequate or approved, the 

budget test must be used in accordance 

with 40 CFR 93.118 to complete all 

applicable regional emissions analyses 

for the 2006 PM2.5 NAAQS. Conformity 

is demonstrated if the transportation 

system emissions reflecting the 

proposed transportation plan, TIP, or 

project not from a conforming 

transportation plan and TIP were less 

than or equal to the motor vehicle 

emissions budget level defined by the 

SIP as being consistent with CAA 

requirements. 

The first submitted SIP for the 2006 

PM2.5 NAAQS may be an attainment 

demonstration or a maintenance plan. 

Nonattainment areas for the 2006 PM2.5

NAAQS could also voluntarily choose 

to submit an ‘‘early progress SIP’’ to 

establish budgets for conformity 

purposes prior to required SIPs. See 

Section V. for further details on 

requirements for early progress SIPs. 

EPA has discussed this option in past 

conformity rule preamble, e.g. the July 

1, 2004 transportation conformity final 

rule (69 FR 40028), and some states 

have established early progress SIP 

budgets for conformity purposes. 

Whatever the case, interim emissions 

tests and/or any existing 1997 PM2.5 SIP 

budget would no longer be used for 

conformity in 2006 PM2.5 areas for direct 

PM2.5 or a relevant precursor once an 

adequate or approved SIP budget for the 

2006 PM2.5 NAAQS is established for 

the pollutant or precursor. Once a SIP 

budget for the 2006 PM2.5 NAAQS is 

adequate or approved, the budget test 

for 2006 PM2.5 conformity would be 

done based on 24-hour emissions (i.e., 

tons per day). As noted earlier in 

Section III.D., areas that were also 

designated for the 1997 PM2.5 NAAQS 

would continue to meet their existing 

conformity requirements for the 1997 

PM2.5 NAAQS, which would include a 

regional emissions analysis based on 

annual emissions (i.e., tons per year). 

The conformity rule at 40 CFR 93.105 

requires consultation on the 

development of SIPs; EPA encourages 

states to consult with MPOs, state and 

local transportation agencies, and local 

air quality agencies sufficiently early 

when developing 2006 PM2.5 SIPs to 

facilitate future conformity 

determinations. Once EPA’s 

nonattainment designations are 

finalized, EPA Regions would be 

available to assist states in developing 

early progress SIPs for the 2006 PM2.5

NAAQS, if desired. 

2. Rationale and Response to Comments 

EPA’s rationale for the use of the 

budget test once adequate or approved 

SIP budgets addressing the 2006 PM2.5

NAAQS are available, and the summary 

of comments received on this provision, 

is found in Section V.A.2. of this 

preamble. It is not repeated here. 

B. Conformity Before 2006 PM2.5 SIP 

Budgets Are Adequate or Approved 

1. Description of the Final Rule 

This portion of the final rule is for 

completing conformity under the 2006 

PM2.5 NAAQS before 2006 PM2.5 SIP 

budgets are established. For areas 

designated nonattainment for the 2006 

PM2.5 NAAQS where all, or a portion, of 

the area is covered by adequate or 

approved 1997 PM2.5 SIP budgets, the 

1997 PM2.5 SIP budgets serve as the 

surrogate for budgets for the 2006 PM2.5

NAAQS until the point when 2006 

PM2.5 SIP budgets are adequate or 

approved. The interagency consultation 

process should be used if there are 

questions about what adequate or 

approved budgets are established in an 

area’s 1997 PM2.5 SIP. In addition, in the 

case where the 1997 budget does not 

cover the entire 2006 PM2.5 area, one of 

the interim emissions tests must also be 

used, as described below. Section IV. of 

today’s rule covers the baseline year to 

be used for the baseline year interim 

emissions test and Section V. covers 

interim emissions tests in 2006 PM2.5

areas before adequate or approved SIP 

budgets for the 2006 PM2.5 NAAQS are 

available. 

Many nonattainment areas for the 

1997 PM2.5 NAAQS may have adequate 

or approved SIP budgets for the 1997 

annual PM2.5 NAAQS. For areas that use 

annual PM2.5 budgets to meet 2006 

PM2.5 requirements, a regional 

emissions analysis would be done based 

on an analysis of annual, rather than 24- 

hour, emissions (i.e., tons per year). 

The final rule creates a new provision 

in § 93.109(k) that covers the four 

possible scenarios that could result 

when areas are designated 

nonattainment for the 2006 PM2.5

NAAQS: 

• Scenario 1: the 2006 PM2.5 area 

nonattainment boundary is the same as 

the 1997 PM2.5 area boundary. 


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37Today’s final rule is based on EPA’s experience 

in establishing conformity requirements for areas 

designated for the 1997 8-hour ozone NAAQS that 

had SIP budgets for the 1-hour ozone NAAQS, 

found in 40 CFR 93.109(e)(2). The four boundary 

scenarios are the same as the four boundary 

scenarios EPA described for the 1997 8-hour ozone 

areas that had existing 1-hour ozone budgets. EPA’s 

2004 guidance entitled, ‘‘Companion Guidance for 

the July 1, 2004 Final Transportation Conformity 

Rule, Conformity Implementation in MultiJurisdictional Nonattainment and Maintenance 

Areas for Existing and New Air Quality Standards,’’ 

(EPA420–B–04–012), contains diagrams of the four 

scenarios for 8-hour ozone areas. Readers may be 

interested in reviewing these diagrams as they read 

the following description of the regulation. This 

document can be found on EPA’s transportation 

conformity website at: http://www.epa.gov/otaq/ 

stateresources/transconf/policy/420b04012.pdf. 

38While the existing regulation for 8-hour ozone 

areas does not explicitly contain this option, it was 

addressed in the preamble to the final rule 

addressing 8-hour ozone areas (July 1, 2004, 69 FR 

40027). 

• Scenario 2: the 2006 PM2.5 area is 

smaller than (and completely within) 

the 1997 PM2.5 area boundary. 

• Scenario 3: the 2006 PM2.5 area is 

larger than (and contains) the 1997 

PM2.5 area boundary. 

• Scenario 4: the 2006 PM2.5 area 

boundary overlaps with a portion of the 

1997 PM2.5 area boundary. 

Most of the 2006 PM2.5 areas that are 

also designated for the 1997 PM2.5

NAAQS are Scenario 1 areas; there are 

areas that belong to Scenarios 2 and 3 

as well. EPA is including rules for all 

four scenarios for the sake of 

completeness.37 The following 

paragraphs describe today’s rule 

provisions for each possible scenario for 

2006 PM2.5 nonattainment areas. 

Scenario 1: 2006 PM2.5 areas where 

the nonattainment boundary is exactly 

the same as the 1997 PM2.5 boundary. In 

this case, the 2006 and 1997 PM2.5

nonattainment boundaries cover exactly 

the same geographic area. Such areas 

must meet the budget test for the 2006 

PM2.5 NAAQS using existing adequate 

or approved SIP budgets for the 1997 

PM2.5 NAAQS. 

Scenario 2: 2006 PM2.5 areas where 

the boundary is smaller than and within 

the 1997 PM2.5 boundary. In this case, 

the 2006 PM2.5 nonattainment area is 

smaller than and completely 

encompassed by the 1997 PM2.5

nonattainment boundary. Such areas 

must meet one of the following versions 

of the budget test: 

• The budget test using the subset or 

portion of existing adequate or approved 

1997 PM2.5 SIP budgets that applies to 

the 2006 PM2.5 nonattainment area, 

where such portion(s) can be 

appropriately identified; or 

• The budget test using the existing 

adequate or approved 1997 PM2.5 SIP 

budgets for the entire 1997 PM2.5

nonattainment area. In this case, any 

additional reductions beyond those 

addressed by control measures in the 

1997 PM2.5 SIP would be required to 

come from the 2006 PM2.5

nonattainment area as described below. 

Under today’s rule, areas could 

choose either test each time they make 

a conformity determination. For any 

particular conformity determination, 

however, the same choice would have to 

be used for each analysis year. EPA 

believes that to do otherwise would be 

unnecessarily complicated and may 

indicate that one test option used 

consistently for all analysis years would 

not demonstrate conformity. The 

consultation process must be used to 

determine whether using a portion of a 

1997 PM2.5 SIP budget is appropriate 

and feasible, and if so, how deriving 

such a portion would be accomplished. 

See the preamble of the July 1, 2004 

final rule (69 FR 40022–40023) for a 

description of a similar provision for the 

1997 8-hour ozone NAAQS. 

A conformity determination using the 

entire 1997 PM2.5 budget would have to 

include a comparison between the onroad regional emissions produced in the 

entire 1997 PM2.5 area and the existing 

1997 PM2.5 SIP budget(s). However, if 

additional reductions are required to 

meet conformity beyond those produced 

by control measures in the 1997 PM2.5

SIP budgets, those reductions must be 

obtained from within the 2006 PM2.5

nonattainment area only, since the 

conformity determination is being made 

for the 2006 PM2.5 NAAQS. 

Scenario 3: 2006 PM2.5 areas where 

the boundary is larger than the 1997 

PM2.5 boundary. In this case, an entire 

1997 PM2.5 nonattainment or 

maintenance area would be within a 

larger 2006 PM2.5 nonattainment area 

and the 1997 PM2.5 budgets would not 

cover the entire 2006 PM2.5

nonattainment area. Such areas are 

required to meet one of the following: 

• The budget test using the 1997 

PM2.5 budget(s) for the 1997 PM2.5 area, 

that is, the portion of the 2006 PM2.5

area that lies within the 1997 PM2.5 area 

boundary, and one of the interim 

emissions tests for either the remaining 

portion of the 2006 PM2.5 nonattainment 

area, the entire 2006 PM2.5 area, or the 

entire portion of the 2006 PM2.5 area 

within an individual state, if 1997 PM2.5

budgets are established in each state in 

a multi-state area; or 

• The budget test using the existing 

adequate or approved 1997 PM2.5 SIP 

budgets for the entire 2006 PM2.5

nonattainment area.38

The budget test must be completed 

according to the requirements in 40 CFR 

93.118, and the interim emissions test 

must follow the requirements of 40 CFR 

93.119. 

Once an area selects a particular 

interim emissions test and the 

geographic area it will address, the same 

test must be used consistently for all 

analysis years. The consultation process 

must be used to determine which 

analysis years should be selected for 

regional emissions analyses where the 

budget test and interim emissions tests 

are used. It may be possible to choose 

analysis years that satisfy both the 

budget and interim emissions test 

requirements for areas using both tests 

prior to adequate or approved 2006 

PM2.5 SIP budgets being established. 

Further information regarding the 

implementation of these requirements is 

illustrated later in this section. 

Scenario 4: 2006 PM2.5 areas where 

the boundary partially overlaps a 

portion of the 1997 PM2.5 boundary. In 

this case, the 1997 and 2006 PM2.5

nonattainment boundaries partially 

overlap. As in the case with Scenario 3 

areas, the 1997 PM2.5 budgets would not 

cover the entire 2006 PM2.5

nonattainment area. However, unlike 

Scenario 3 areas, the 2006 area does not 

contain the entire 1997 PM2.5

nonattainment or maintenance area. 

Therefore, 1997 PM2.5 budgets cannot be 

the sole test of conformity for the 2006 

PM2.5 NAAQS, since a conformity 

determination must include a regional 

emissions analysis that includes the 

entire 2006 PM2.5 nonattainment area. 

The 2006 PM2.5 areas covered under 

this scenario must use the 1997 PM2.5

budget(s) to meet the budget test for the 

portion of the 1997 PM2.5 area and 

budgets that overlap with the 2006 

PM2.5 area boundary, and one of the 

interim emissions tests for either the 

remaining portion of the 2006 PM2.5

nonattainment area, the entire 2006 

PM2.5 area, or the entire portion of the 

2006 PM2.5 area within an individual 

state, if 1997 PM2.5 budgets are 

established in each state in a multi-state 

area. Under this final rule, the budget 

test must be completed according to the 

requirements in 40 CFR 93.118, and the 

interim emissions test must follow the 

requirements of 40 CFR 93.119. 

Similar to Scenario 3 areas, once an 

area selects a particular interim 

emissions test and the geographic area 

it will address, the same test must be 

used consistently for all analysis years. 

Further information regarding the 

implementation of these requirements is 

found in the discussion above for 

Scenario 3, and illustrated later in this 

section. 


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2. Rationale and Response to Comments 

General. EPA believes that using the 

existing 1997 PM2.5 budgets as a 

surrogate for the 2006 PM2.5 NAAQS is 

required by the CAA. In Environmental 

Defense v. EPA, 467 F.3d 1329 (D.C. Cir. 

2006), the Court of Appeals for the 

District of Columbia Circuit held that 

where a motor vehicle emissions budget 

developed for the revoked 1-hour ozone 

NAAQS existed in an approved SIP, that 

budget must be used to demonstrate 

conformity to the 8-hour ozone NAAQS 

until the SIP is revised to include 

budgets for the new NAAQS. EPA 

reflected the court’s decision for ozone 

conformity tests in its January 24, 2008 

final rule (73 FR 4434). 

While the Environmental Defense 

case concerned ozone, EPA believes the 

court’s holding is relevant for other 

pollutants for which conformity must be 

demonstrated. Consequently, EPA 

believes that 2006 PM2.5 areas that have 

1997 PM2.5 budgets must use them for 

2006 PM2.5 conformity before 2006 

PM2.5 SIP budgets are established. 

The use of the 1997 PM2.5 budgets as 

a surrogate for the 2006 PM2.5 NAAQS 

also would ensure that CAA 

requirements are met. Section 176(c) of 

the CAA requires that transportation 

activities may not cause or contribute to 

new violations, worsen existing 

violations, or delay timely attainment or 

any interim milestones. In these areas, 

the budgets for the 1997 annual PM2.5

NAAQS have been the measure of PM2.5

conformity thus far, and have been 

consistent with these areas’ PM2.5 air 

quality progress to date. Therefore, 

using budgets that address the 1997 

annual PM2.5 NAAQS where no other 

PM2.5 budgets are available ensures that 

the requirements of CAA 176(c) are met. 

Once 2006 PM2.5 budgets are found 

adequate or approved, the budget test 

for that NAAQS provides the best means 

to determine whether transportation 

plans, TIPs, or projects meet CAA 

requirements. 

The budget test is also a better 

environmental measure than the interim 

emissions tests when SIP budgets for a 

pollutant or precursor are available. As 

EPA reiterated in its July 1, 2004 final 

rule (69 FR 40026), when motor vehicle 

emissions budgets have been 

established by SIPs, they provide a more 

relevant basis for conformity 

determinations than the interim 

emissions tests. EPA believes this is true 

even though in most cases the budgets 

established for the 1997 PM2.5 NAAQS 

would address an annual rather than a 

24-hour NAAQS. A 1997 PM2.5 budget 

represents the state’s best estimate of the 

level of permissible PM2.5 emissions 

from the on-road transportation sector 

for a particular area. Such a budget is 

created based on local information for 

that particular area—its population, its 

estimated vehicle miles traveled and 

other travel data, its transit availability, 

its particular vehicle fleet, its local 

controls, and so forth. Hence EPA 

believes using budgets, designed for 

specific areas and based on information 

from those specific areas, is preferable 

to using either of the more generic 

interim emissions tests. The baseline 

year and the build/no-build tests are 

sufficient for demonstrating conformity 

when an area does not have a budget for 

a portion of a nonattainment area. 

However, these interim emissions tests 

usually do not ensure that 

transportation emissions promote 

progress for the NAAQS to the same 

extent that the use of motor vehicle 

emissions budgets do. 

In addition, using the 1997 PM2.5

budgets for 2006 PM2.5 conformity 

purposes may also streamline the 

conformity process for areas designated 

nonattainment for both the 1997 and 

2006 PM2.5 NAAQS. These areas would 

already be using 1997 PM2.5 budgets for 

conformity of that NAAQS. In areas 

where the 1997 and 2006 PM2.5

nonattainment boundaries are the same 

(Scenario 1), today’s final rule requires 

these areas to meet only one type of 

test—the budget test—to demonstrate 

conformity for both the 1997 and 2006 

PM2.5 NAAQS, although the attainment 

year, which is a required analysis year, 

will be different for these two NAAQS. 

For multi-state 2006 PM2.5

nonattainment areas, today’s final rule 

preserves states’ ability to determine 

conformity independently from one 

another, if a state has already 

established budgets for its own state 

(and/or MPO(s)) for the 1997 PM2.5

NAAQS. Further explanation and 

examples are given below in Section 

VI.C. 

While today’s final rule concerns the 

2006 PM2.5 NAAQS, this same rationale 

regarding conformity tests would apply 

for future new or revised NAAQS of any 

transportation-related criteria pollutant. 

Therefore, EPA may amend the rule in 

the future to apply the conformity test 

language found in today’s § 93.109(j) 

and (k) more generally. EPA is not doing 

so in today’s final rule as such a 

provision was not proposed, and EPA 

intends to solicit and consider public 

comments on applying this language to 

future new or revised NAAQS before 

adopting any such provision. 

Scenario 1 and 2 areas. Today’s final 

rule for conformity in 2006 PM2.5 areas 

before budgets that address that NAAQS 

are available is largely consistent with 

the process that EPA finalized for 8- 

hour ozone areas designated under the 

1997 ozone NAAQS where 1-hour ozone 

budgets exist (69 FR 40021–40028). 

Requirements for Scenario 1 and 2 areas 

are identical to the final rule for these 

8-hour ozone areas. Scenario 2 2006 

PM2.5 areas also have the choice of 

adjusting the existing 1997 PM2.5

budgets for the new geographical area. 

As we indicated in the November 5, 

2003 proposed rule for the 8-hour ozone 

areas (68 FR 62702), using the relevant 

portion of existing budgets for purposes 

of conducting conformity 

determinations for a different NAAQS of 

the same pollutant is appropriate since 

the budgets for the 1997 PM2.5 NAAQS 

would only be used as a surrogate for 

the 2006 PM2.5 NAAQS. These 1997 

PM2.5 budgets still have to be met in the 

1997 PM2.5 areas. 

Scenario 3 and 4 areas. Some 

Scenario 3 areas and all Scenario 4 areas 

must also meet one of the interim 

emissions tests, for either the portion of 

the 2006 PM2.5 area not covered by the 

1997 PM2.5 SIP budgets, the entire PM2.5

area, or the entire portion of the 2006 

PM2.5 area within an individual state. As 

explained in the November 2003 

proposed rule for 8-hour ozone areas (68 

FR 62702), in these cases budgets 

cannot be the sole test of conformity 

because a conformity determination 

must include a regional emissions 

analysis that covers the entire 

nonattainment area. 

However, some Scenario 3 areas may 

be able to demonstrate conformity 

without an interim emissions test. 

Scenario 3 PM2.5 areas have an option 

that similar 8-hour ozone areas also 

have: The entire larger, newly 

designated area could meet budgets 

established for the smaller, existing 

area. In the July 1, 2004 final rule, EPA 

clarified that 8-hour ozone areas have 

this option. In that final rule, EPA noted 

that while this option was not explicitly 

addressed by the regulatory text, it is 

consistent with the requirements and is 

available to interested 8-hour ozone 

areas (69 FR 40027). 

Finally, EPA believes that statutory 

requirements are met under the 

proposal to use either interim emissions 

test when no adequate or approved 

PM2.5 SIP budgets are available. See 

further rationale regarding this 

flexibility in today’s final rule in 

Section V. 

EPA did not receive any specific 

comments on this portion of the 

rulemaking, but one commenter 

supported the use of EPA’s 2004 multijurisdictional guidance for 2006 PM2.5

areas. This guidance, discussed further 


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39This section of the guidance covers how 8-hour 

ozone areas that have 1-hour ozone budgets would 

proceed with developing their regional emissions 

analyses and making conformity determinations, 

which is analogous to any 2006 PM2.5 areas that 

have 1997 budgets in the interim. 

below in C.2. of this section, reflects the 

requirements finalized today. 

C. General Implementation of Regional 

Tests 

Today’s final rule applies the existing 

conformity rule’s general requirements 

for PM2.5 regional emissions analyses to 

all 2006 PM2.5 areas. As described in 

Section V.C., EPA is including this 

discussion of the existing regulation’s 

requirements for clarity, to help readers 

understand how the existing regulation 

would apply to areas designated 

nonattainment for the 2006 PM2.5

NAAQS. 

The discussion below is intended to 

illustrate how today’s rule will be 

implemented in practice for 2006 PM2.5

areas with adequate or approved 1997 

PM2.5 SIP budgets. 

1. Conformity Test Requirements for 

Most Areas 

Regional emissions analyses under 

today’s final rule must be implemented 

through existing conformity 

requirements such as 40 CFR 93.118, 

93.119, and 93.122. For example, the 

conformity rule requires that only 

certain years within the transportation 

plan (or alternate timeframe) be 

examined. 

The consultation process must be 

used to determine which analysis years 

should be selected for regional 

emissions analyses for the budget test. 

The conformity rule at 40 CFR 

93.118(d)(2) requires the following 

analysis years for this test: 

• The attainment year for the 2006 

PM2.5 NAAQS (if it is within the 

timeframe of the transportation plan and 

conformity determination); 

• The last year of the timeframe of the 

conformity determination (40 CFR 

93.106(d)); and 

• Intermediate years as necessary so 

that analysis years are no more than ten 

years apart. 

Areas covered by § 93.109(k) of 

today’s final rule will also be 

determining conformity for the 1997 

PM2.5 NAAQS, using adequate or 

approved budgets established for that 

NAAQS, although there will be some 

differences in analysis years required for 

the 2006 and 1997 PM2.5 NAAQS (e.g., 

the attainment year, which is a required 

analysis year, will be different for these 

two NAAQS). 

See the relevant regulatory sections of 

the conformity rule and the July 1, 2004 

final rule preamble for further 

background on how tests have been 

implemented for other pollutants and 

standards (69 FR 40020). 

2. Cases Involving Multi-Jurisdictional 

Areas 

As described earlier, EPA issued a 

guidance document in 2004 for 

implementing conformity requirements 

in multi-jurisdictional areas. There are 

two parts of this existing guidance that 

are relevant for implementing 

conformity for these areas. Part 3 of the 

existing guidance describes how 

conformity would be implemented in all 

2006 PM2.5 areas once adequate or 

approved SIP budgets for the 2006 PM2.5

NAAQS are established. Part 4 of this 

guidance is relevant for meeting 

conformity requirements when only 

1997 PM2.5 budgets are available.39

This guidance is also applicable for 

conformity purposes in multi-state and 

multi-MPO areas. For example, in multistate 2006 PM2.5 nonattainment areas 

where each state has its own 1997 PM2.5

SIP budgets, the states could determine 

conformity for the 2006 NAAQS (as well 

as the 1997 PM2.5 NAAQS) 

independently of each other. In 

addition, MPOs in areas that have 

subarea budgets for the 1997 PM2.5

NAAQS could use these subarea 

budgets for conformity to the 2006 PM2.5

NAAQS. 

For further information, please refer 

to Section V.C. and EPA’s 2004 multijurisdictional conformity guidance. 

VII. Other Conformity Requirements for 

2006 PM2.5 Areas 

The conformity regulations already 

provide the remaining requirements that 

are necessary for conformity under the 

2006 PM2.5 NAAQS. Any existing 

conformity requirements that are listed 

for ‘‘PM2.5’’ areas that have not been 

revised by today’s final rule apply to 

2006 PM2.5 nonattainment or 

maintenance areas as well. These 

provisions have already been 

promulgated, based on past rulemakings 

and rationale, and are unchanged by 

today’s rule. For example, a hot-spot 

analysis is required for certain projects 

in any PM2.5 nonattainment and 

maintenance areas before such projects 

can be found to conform. These 

requirements are found in §§ 93.116(a) 

and § 93.123(b) of the conformity rule, 

although please note that EPA for other 

reasons has clarified amendments to 

section 93.116(a) in today’s final rule; 

see Section IX. The hot-spot analysis 

requirements that were promulgated for 

‘‘PM2.5’’ areas in the conformity rule did 

not need to be amended to apply to 

2006 PM2.5 areas, because they already 

apply for this NAAQS. 

A hot-spot analysis in an area 

designated for both the 1997 and 2006 

PM2.5 NAAQS would have to 

demonstrate that the project meets the 

conformity rule’s hot-spot requirements 

for all of the PM2.5 NAAQS for which 

the area is designated nonattainment: 

• If an area is designated 

nonattainment for only the 2006 PM2.5

NAAQS, the analysis would have to 

consider only this NAAQS; 

• If an area is designated 

nonattainment for the 1997 annual 

NAAQS and the 2006 24-hour NAAQS, 

the analysis would have to consider 

both NAAQS; 

• If an area is designated 

nonattainment for both the 1997 annual 

and 1997 24-hour NAAQS, as well as 

the 2006 24-hour NAAQS, the analysis 

would have to consider all of these 

NAAQS. 

Please refer to the March 10, 2006 

final rule for additional information 

regarding hot-spot analyses (47 FR 

12468) and EPA and FHWA’s current 

guidance for implementing this 

requirement (Transportation Conformity 

Guidance for Qualitative Hot-spot 

Analyses in PM2.5 and PM10

Nonattainment and Maintenance Areas, 

March 2006, EPA420–B–06–902). EPA 

will also be releasing PM quantitative 

hot-spot modeling guidance in the near 

future. Please check EPA’s Web site at: 

http://www.epa.gov/otaq/ 

stateresources/transconf/policy.htm. 

Section 93.117 of the conformity rule, 

which requires project-level conformity 

determinations to comply with any 

PM2.5 control measures in an approved 

SIP, also applies for conformity under 

the 2006 PM2.5 NAAQS. Again, EPA 

promulgated this requirement in general 

for nonattainment and maintenance 

areas under the PM2.5 NAAQS. See 

EPA’s July 2004 final rule for further 

information on this requirement (69 FR 

40036–40037). 

EPA will work with PM2.5

nonattainment areas as needed to ensure 

that state and local agencies can meet 

existing and new conformity 

requirements for the 2006 PM2.5 NAAQS 

in a timely and efficient manner. 

VIII. Transportation Conformity in 

PM10 Nonattainment and Maintenance 

Areas and the Revocation of the Annual 

PM10 NAAQS 

A. Background 

On October 17, 2006, EPA issued a 

final rule establishing changes to the 

PM2.5 and PM10 NAAQS (71 FR 61144). 

The October 2006 final rule retained the 


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40Transportation Conformity in PM10

Nonattainment and Maintenance Areas and the 

Revocation of the Annual PM10 Standard, 

September 25, 2008, found on EPA’s Web site at: 

http://www.epa.gov/otaq./stateresources/transconf/ 

policy.htm. 

24-hour PM10 NAAQS of 150 μg/m3, and 

revoked the annual PM10 NAAQS of 50 

μg/m3. EPA made a commitment in the 

October 2006 final rule to provide 

information regarding how 

transportation conformity will be 

implemented under the revised PM10

NAAQS (71 FR 61215). To satisfy this 

commitment, EPA described which 

conformity tests would apply in PM10

nonattainment and maintenance areas 

(‘‘PM10 areas’’) in a guidance 

document.40 Today’s final rule updates 

the conformity rule in response to this 

commitment. 

CAA section 176(c)(5) requires 

conformity only in areas that are 

designated nonattainment or 

maintenance for a given pollutant and 

NAAQS. Therefore, transportation 

conformity has continued to apply to all 

PM10 nonattainment and maintenance 

areas because transportation conformity 

applies based on an area’s status as a 

nonattainment or maintenance area, and 

PM10 designations were not affected by 

the October 2006 final rule. As stated in 

the October 2006 final rule, ‘‘both 

transportation and general conformity 

will continue to apply to all PM10

nonattainment and maintenance areas 

since no designations are changing’’ (71 

FR 61215). 

As of the effective date of the October 

2006 rule, conformity determinations in 

PM10 areas have been required only for 

the 24-hour PM10 NAAQS. The October 

2006 final rule stated, ‘‘However, 

because EPA is revoking the annual 

PM10 NAAQS in this final rule, after the 

effective date of this rule conformity 

determinations in PM10 areas will only 

be required for the 24-hour PM10

NAAQS; conformity to the annual PM10

NAAQS will no longer be required’’ (71 

FR 61215). Please refer to the October 

17, 2006 final rule for additional 

information (71 FR 61144). 

B. Description of the Final Rule 

EPA has added two new definitions to 

40 CFR 93.101 of the conformity rule to 

distinguish between the 24-hour PM10

NAAQS and the annual PM10 NAAQS. 

EPA has also updated 40 CFR 93.109(g) 

so that: 

• PM10 areas that have adequate or 

approved SIP budgets for both the 24- 

hour and annual PM10 NAAQS are 

required to use only the budgets 

established for the 24-hour PM10

NAAQS. Conformity to the annual PM10

budgets in such a case is no longer 

required. 

• PM10 areas that have adequate or 

approved SIP budgets for only the 

annual PM10 NAAQS are required to use 

them for PM10 conformity 

determinations until PM10 SIP budgets 

for the 24-hour PM10 NAAQS are found 

adequate or approved. For areas that use 

annual PM10 budgets, a regional 

emissions analysis must be done based 

on an analysis of annual, rather than 24- 

hour, emissions. 

No other conformity requirements for 

PM10 nonattainment and maintenance 

areas have been changed by the final 

rule. For example, the requirement for 

project-level conformity determinations 

in PM10 areas continues to apply, 

including hot-spot analyses in some 

cases (see §§ 93.116(a) and 93.123(b)). 

Although project-level conformity 

requirements and any required hot-spot 

analyses apply only with respect to the 

24-hour PM10 NAAQS, this requires no 

revisions to the conformity rule to 

implement. 

Where an area has adequate or 

approved PM10 budgets for both the 

annual and 24-hour PM10 NAAQS, it is 

not necessary to remove the annual 

PM10 NAAQS budgets from the SIP. 

Such annual budgets do not apply for 

conformity purposes if an area has 

budgets for the 24-hour PM10 NAAQS. 

However, states can choose to revise 

such SIPs to remove any annual PM10

budgets, since this NAAQS has been 

revoked and remaining 24-hour PM10

budgets ensure that anti-backsliding SIP 

requirements are met. 

C. Rationale and Response to Comments 

Today’s update to the rule for PM10

conformity tests results from the 

revocation of the annual PM10 NAAQS. 

In areas where annual PM10 budgets are 

the only PM10 budgets that are adequate 

or approved, EPA believes it is 

necessary to use such budgets to 

demonstrate conformity for the 24-hour 

PM10 NAAQS to meet CAA 

requirements. As discussed above in 

Section VI.B.2., a 2006 decision by the 

Court of Appeals for the DC Circuit 

clarified this point. In this decision, the 

court stated, ‘‘A current SIP, even one 

tied to outdated NAAQS, remains in 

force until replaced by another but laterapproved SIP. The CAA provides that 

the current SIPs are legally sufficient 

until they are replaced by new SIPs.’’ 

(Environmental Defense v. EPA, 467 

F.3d 1329, 1335 (DC Cir. 2006)). Refer 

to Section VI.B.2. for further 

information about the decision. EPA 

believes that today’s final rule is 

consistent with this decision. 

Consequently, EPA believes that 

annual PM10 budgets must be used to 

demonstrate conformity for the 24-hour 

PM10 NAAQS when adequate or 

approved 24-hour PM10 budgets are not 

yet established. In areas with PM10

budgets that address only the annual 

PM10 NAAQS, these budgets have been 

the measure of PM10 conformity thus 

far, and have been consistent with these 

areas’ PM10 air quality progress to date. 

Therefore, using annual PM10 budgets 

where no other PM10 SIP budgets are 

available ensures that air quality 

progress to date is maintained, air 

quality will not be worsened and 

attainment and any interim milestones 

for the 24-hour PM10 NAAQS will not 

be delayed because of emissions 

increases. Once 24-hour PM10 budgets 

are found adequate or approved, the 

budget test using only the budgets for 

the 24-hour PM10 NAAQS provides the 

best means to determine whether 

transportation plans, TIPs, or projects 

meet CAA conformity requirements. 

Most PM10 areas already have 

adequate or approved budgets for only 

the 24-hour PM10 NAAQS. However, 

there are a limited number of PM10 areas 

that have SIP budgets only for the 

annual PM10 NAAQS. EPA believes that 

the statute as interpreted by the court 

requires such areas to continue to use 

these adequate or approved annual PM10

SIP budgets, rather than use one of the 

interim emissions tests in 40 CFR 

93.119(d) which could be less 

environmentally protective tests than 

SIP budgets. 

While EPA addressed how the 

revocation affected PM10 transportation 

conformity requirements in its 

September 2008 guidance, updating the 

regulation clarifies the requirements and 

simplifies implementation. This final 

rule also saves resources in some areas 

with adequate or approved SIP budgets 

for both the 24-hour and annual PM10

NAAQS because these areas are no 

longer required to use budgets for the 

annual PM10 NAAQS. As mentioned 

above, today’s minor revision to the 

conformity rule is consistent with what 

is already required in the field for PM10

nonattainment and maintenance areas. 

EPA received one comment 

supporting this rule change and no 

comments opposing it. 

IX. Response to the December 2007 HotSpot Court Decision 

A. Background 

EPA promulgated a final rule on 

March 10, 2006 (71 FR 12468) that 

revised the previous PM10 conformity 

hot-spot analysis requirements and 

applied these revised requirements to 


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41The March 10, 2006 rule constituted final 

action on EPA’s original proposal from November 

5, 2003 (68 FR 62690, 62712) and a supplemental 

proposal from December 13, 2004 (69 FR 72140, 

72144–45, and 72149–50). 

42Section 93.123(b) contains the types of projects 

for which a hot-spot analysis applies in PM2.5 and 

PM10 areas. For additional discussion, please refer 

to ‘‘V. Projects of Air Quality Concern and General 

Requirements for PM2.5 and PM10 Hot-Spot 

Analyses’’ in the preamble of the March 10, 2006 

final rule at 71 FR 12490–12498. 

43EPA and petitioners settled a third issue that 

was not raised to the court. The settlement was 

finalized on June 22, 2007 (72 FR 34460), and 

described a stakeholder process that EPA will use 

to develop its future PM2.5 and PM10 quantitative 

hot-spot modeling guidance. 

PM2.5.41 A hot-spot analysis is defined 

in 40 CFR 93.101 as an estimation of 

likely future localized pollutant 

concentrations and a comparison of 

those concentrations to relevant 

NAAQS. A hot-spot analysis assesses 

the air quality impacts of an individual 

transportation project on a scale smaller 

than a regional emissions analysis for an 

entire nonattainment or maintenance 

area. 

Prior to today, section 93.116(a) of the 

conformity rule read: ‘‘* * * The 

FHWA/FTA project must not cause or 

contribute to any new localized CO, 

PM10, and/or PM2.5 violations or 

increase the frequency or severity of any 

existing CO, PM10, and/or PM2.5

violations * * *.’’ These requirements 

continue to apply in today’s rule, and 

are satisfied for applicable projects 42 ‘‘if 

it is demonstrated that during the time 

frame of the transportation plan no new 

local violations will be created and the 

severity or number of existing violations 

will not be increased as a result of the 

project.’’ Sections 93.105(c)(1)(i) and 

93.123 contain the consultation and 

methodology requirements for 

conducting hot-spot analyses. 

A hot-spot analysis, when required, is 

only one part of a project-level 

conformity determination. In order to 

meet all CAA requirements, an 

individual project must also be included 

in a conforming transportation plan and 

TIP (and regional emissions analysis for 

the entire nonattainment or 

maintenance area) and meet any other 

applicable requirements. 

Environmental petitioners challenged 

the March 2006 final rule, and raised 

several issues related to it. First, 

petitioners alleged that the final rule did 

not ensure that transportation projects 

complied with CAA section 176(c)(1)(A) 

and (c)(1)(B)(iii). Second, petitioners 

alleged that EPA had previously 

approved its MOBILE6.2 on-road mobile 

source emissions model for use in 

quantitative PM2.5 and PM10 hot-spot 

analyses, and withdrew such approval 

in the March 2006 final rule without 

providing adequate notice and 

opportunity for public comment.43

On December 11, 2007, the D.C. 

Circuit Court of Appeals issued its 

decision, and upheld EPA’s March 2006 

final rule and remanded one issue for 

clarification. Environmental Defense v. 

EPA, 509 F.3d. 553 (D.C. Cir. 2007). The 

court agreed with EPA’s position that 

CAA section 176(c)(1)(A) does not 

require that an individual transportation 

project reduce emissions, but only that 

such a project not worsen air quality 

compared to what would have 

otherwise occurred if the project was 

not implemented. The court held that, 

assuming section 176(c)(1)(A) applies in 

the local area surrounding an individual 

project, EPA’s position that this 

provision is met if a transportation 

project conforms to the emissions 

estimates and control requirements of 

the SIP was a reasonable one. The court 

also rejected petitioners’ arguments 

regarding MOBILE6.2 and found that 

EPA had in fact provided adequate 

notice and comment on its decision not 

to require quantitative PM hot-spot 

analyses using MOBILE6.2 due to the 

model’s technical limitations at the 

project-level (71 FR 12498–12502). 

However, the court remanded one 

issue to EPA for further explanation of 

the Agency’s interpretation of CAA 

section 176(c)(1)(B)(iii). The court 

instructed EPA on remand to interpret 

how this provision of the Act is met 

within the local area affected by an 

individual project, or explain why this 

statutory provision does not apply 

within such an area. Today’s final rule 

responds to this part of the court’s 

decision. 

B. Description of the Final Rule 

EPA has made two changes to section 

93.116(a) of the conformity rule to 

address the court’s remand. First, EPA 

is explicitly stating in this provision 

that federally funded or approved 

highway and transit projects in PM2.5

and PM10 nonattainment and 

maintenance areas must meet the 

requirements of CAA section 

176(c)(1)(B)(iii) within the local area 

affected by the project. That is, 

§ 93.116(a) now expressly says that 

project must not delay timely 

attainment or any interim milestones. 

EPA has also explicitly stated in 

§ 93.116 the requirement that projects 

must be included in a regional 

emissions analysis under 40 CFR 93.118 

or 93.119. Consistent with the court’s 

decision, as explained below, EPA is not 

requiring an individual project to 

reduce emissions in the local project 

area. 

These revisions are intended to clarify 

and make more explicit EPA’s 

longstanding interpretation of the CAA 

as it applies to hot-spot analyses, and do 

not reflect any substantive changes to 

existing requirements for project-level 

conformity determinations. Under 

today’s final rule, project-level 

conformity determinations, including 

any hot-spot analyses, will continue to 

be performed in the same manner as 

current practice. Projects will continue 

to be required to be a part of a regional 

emissions analysis that supports a 

conforming transportation plan and TIP. 

Hot-spot analyses will need to 

demonstrate that during the time frame 

of the transportation plan no new local 

violations would be created and the 

severity or number of existing violations 

would not be increased as a result of a 

new project. By making these 

demonstrations, it can be assured that 

the project would not delay timely 

attainment or any required interim 

reductions or milestones, as described 

further below. In addition, project 

sponsors must continue to document 

the hot-spot analysis as part of the 

project-level conformity determination, 

and the public continues to be able to 

comment on any aspects of the 

conformity determination through 

existing public involvement 

requirements. 

EPA notes that today’s final rule also 

addresses new projects in CO 

nonattainment and maintenance areas, 

since the hot-spot analysis requirements 

in section 93.116(a) also apply to such 

areas. Although the March 2006 final 

rule and the December 2007 court case 

did not involve CO hot-spot 

requirements, EPA believes it is 

appropriate to clarify that CAA section 

176(c)(1)(B)(iii) must also be met for 

projects in CO nonattainment and 

maintenance areas. 

C. Rationale and Response to Comments 

1. General 

Project-level conformity 

determinations must demonstrate that 

all of the requirements in CAA section 

176(c)(1)(B) are met. Section 

176(c)(1)(B) defines conformity to a SIP 

to mean ‘‘that such activities will not (i) 

cause or contribute to any new violation 

of any NAAQS in any area; (ii) increase 

the frequency or severity of any existing 

violation of any NAAQS in any area; or 

(iii) delay timely attainment of any 

NAAQS or any required interim 

emission reductions or other milestones 

in any area.’’ 


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44Hot-spot analyses must be based on the latest 

data and models under 40 CFR 93.109(b), 93.111, 

and 93.123, and therefore any growth in other 

emissions sources or the impact of new or existing 

emissions controls (including those in any required 

SIP) would always be considered in a hot-spot 

analysis prior to approving a project. 

45This requirement is in section 93.116(b) of the 

conformity rule. 

In Environmental Defense, the court 

held that EPA did not adequately 

explain how it interpreted the language 

of CAA section 176(c)(1)(B)(iii) in 

conjunction with related language in 

sections 176(c)(1)(B)(i) and (ii). The 

court stated that, if ‘‘any area’’ in the first 

two provisions refers to a ‘‘local area,’’ 

then EPA must either interpret the term 

‘‘any area’’ in section 176(c)(1)(B)(iii) to 

also mean ‘‘local area,’’ or explain why 

a different interpretation is reasonable. 

509 F.3d at 560–61. EPA believes that 

‘‘any area’’ as used in the first two 

provisions does include local areas, and 

that the same interpretation should 

apply to the third provision as well; 

therefore all of section 176(c)(1)(B) 

requirements must be met in the local 

project area. 

EPA believes that its conformity hotspot regulations, as well as other 

conformity requirements, already 

require that individual projects comply 

with section 176(c)(1)(B)(iii) in the local 

project area. EPA has always intended 

the term ‘‘any area’’ in all three statutory 

provisions of section 176(c)(1)(B) to 

include the local area affected by the 

emissions produced by a new project. 

For example, as EPA stated in the March 

2006 final hot-spot rule (71 FR 12483), 

‘‘a regional emissions analysis for an 

area’s entire planned transportation 

system is not sufficient to ensure that 

individual projects meet the 

requirements of section 176(c)(1)(B) 

where projects could have a localized 

air quality impact.’’ 

To implement section 176(c)(1)(B) 

requirements in PM2.5, PM10, and CO 

nonattainment and maintenance areas 

(40 CFR 93.109(b)), EPA’s conformity 

rule has required and continues to 

require project-level conformity 

determinations to address the regional 

and local emissions impacts from new 

projects. Section 93.115(a) of the 

conformity rule requires that an 

individual project must be consistent 

with the emissions projections and 

control measures in the SIP, either by 

inclusion in a conforming transportation 

plan and TIP or through a separate 

demonstration (and regional emissions 

analysis developed under 40 CFR 

93.118 or 93.119). In addition, section 

93.116(a) requires that some projectlevel conformity determinations include 

a hot-spot analysis that demonstrates 

emissions from a single project do not 

negatively impact air quality within the 

area substantially affected by the 

project.44 EPA concludes that through 

meeting all of these requirements, it can 

be assured that a project does not cause 

or contribute to a new violation, worsen 

a violation, or delay timely attainment 

or any interim milestones. 

However, in light of the court’s 

request for further explanation, today’s 

rule specifically clarifies that the term 

‘‘any area’’ in CAA section 176(c)(1)(B) 

applies to any portion of a 

nonattainment or maintenance area, 

including the local area affected by a 

transportation project. Today’s final rule 

thus ensures that transportation 

planners address the requirement that 

there be no delay in timely attainment 

or any interim milestones in the local 

project area. 

EPA notes that CAA section 

176(c)(1)(B)(iii) does not require that 

transportation activities provide 

additional emissions reductions in a 

local project area in order to meet the 

requirement not to delay timely 

attainment or any interim milestones. 

EPA explained this interpretation in the 

preamble to its March 2006 hot-spot 

regulations (71 FR 12482), and the court 

upheld this interpretation in 

Environmental Defense v. EPA (509 F.3d 

553, 560 (D.C. Cir. 2007). See also 

Environmental Defense v. EPA, 467 F.3d 

1329, 1337 (DC Cir. 2006) (‘‘EPA argues, 

and we agree, that conformity to a SIP 

can be demonstrated by using the build/ 

no-build test, even if individual 

transportation plans do not actively 

reduce emissions’’). CAA section 

176(c)(1)(B)(iii) does not require a new 

project to mitigate new or worsened air 

quality violations that it does not cause. 

This statutory provision also does not 

require a new project to contribute new 

interim reductions beyond those that are 

already required in the SIP. Rather, the 

hot-spot determination must instead 

conclude that the new project, in 

conjunction with all other emissions 

increases and decreases in the local 

project area, is consistent with the 

emissions budgets in the SIP and does 

not produce any new or worsen any 

existing violations. 

The only case where Congress 

specifically required individual projects 

to provide emission reductions in hotspot analyses is for projects in certain 

CO nonattainment areas. CAA section 

176(c)(3)(B)(ii) requires individual 

projects in CO nonattainment areas to 

‘‘eliminate or reduce the severity and 

number of violations of the carbon 

monoxide NAAQS in areas substantially 

affected by the project.’’ 45 Since 

Congress did not establish such a 

requirement for any project in PM2.5 and 

PM10 areas under section 

176(c)(3)(B)(ii), and for the reasons 

described in today’s final rule, EPA does 

not interpret such a requirement to 

apply to projects in PM2.5 or PM10 areas 

under section 176(c)(1)(B)(iii). 

Some commenters supported EPA’s 

interpretation, while others disagreed. 

The other commenters believed that, 

despite the court’s decision, a project 

should not be allowed to proceed unless 

it reduces emissions sufficient to offset 

emissions from other sources that 

negatively impact meeting the NAAQS. 

Commenters thought today’s rule would 

allow a project to conform even when 

there are NAAQS violations after the 

attainment date and that EPA’s rule 

eliminates the opportunity to identify 

and remedy violations. 

The commenters’ argument—that 

section 176(c)(1)(B)(iii) requires 

transportation projects to reduce 

emissions in the area affected by the 

project—has been raised in earlier 

transportation conformity rulemakings 

and repeatedly rejected by the D.C. 

Circuit Court of Appeals. In 

Environmental Defense Fund v. EPA, 

the court explained that ‘‘[a]lthough the 

Act states that SIPs must reduce 

violations, and therefore emissions, it is 

notably silent on whether transportation 

plans themselves, which are but one 

part of the SIP, must reduce emissions.’’ 

467 F.3d 1329, 1338 (D.C. Cir. 2006) 

(emphasis in original). The court went 

on to uphold as reasonable EPA’s 

interpretation that individual 

transportation plans need not reduce 

emissions to comply with the statutory 

requirement to conform to the SIP. Id. 

In the 2006 EDF decision, the court also 

referred to its earlier decision in 

Environmental Defense Fund v. EPA, 82 

F.3d. 451 (D.C. Cir. 1996), in which it 

rejected a challenge to EPA’s 1993 

conformity regulations for similar 

reasons. In the 2006 EDF decision, the 

court noted that it had previously 

decided a similar issue in the 1996 EDF 

opinion, in which it ‘‘agreed with EPA 

‘that plans and improvement programs 

may contribute to emissions reductions 

by avoiding or reducing increases in 

emissions over the years,’ because 

although the statute ‘require[d] 

reductions in [several pollutants],’ it 

‘d[id] not require that the emissions 

come entirely from mobile sources’[.]’’ 

EDF v. EPA, 467 F.3d at 1338. Thus, the 

2006 EDF decision was the second time 

the D.C. Circuit rejected the same 


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46 Definitions from Webster’s On-line Dictionary, 

see http://www.websters-online-dictionary.org/. 

argument commenters raise here. The 

fact that the 1996 and 2006 D.C. Circuit 

decisions addressed transportation 

plans and TIPs, rather than individual 

projects, is not relevant because the 

court’s analysis of what section 

176(c)(1) requires applies equally to 

transportation plans, TIPs, and 

individual projects, since section 176(c) 

imposes the same requirements for all 

three, and contains no additional or 

different requirements for individual 

projects. 

In its 2007 decision in Environmental 

Defense v. EPA, the court for a third 

time upheld EPA’s interpretation that a 

transportation project that does not 

increase violations of the NAAQS 

conforms to the SIP’s purpose of 

eliminating or reducing the severity and 

number of NAAQS violations and 

achieving expeditious attainment of the 

NAAQS, even if the project does not 

itself achieve emissions reductions. 509 

F.3d 553, 560 (DC Cir. 2007). In that 

decision, the court did remand to EPA 

for further explanation the issue of 

whether section 176(c)(1)(B)(iii) applies 

to hot-spot analyses, and if it does, how 

its conditions are to be met. Today’s 

final rule responds to that remand. As 

explained below, EPA interprets section 

176(c)(1)(B)(iii) as applying to hot-spot 

analyses, and the requirements of the 

regulations as amended in today’s 

action will ensure that transportation 

projects do not interfere with timely 

attainment of the NAAQS or any interim 

milestones. 

Section 176(c)(1) prohibits federal 

agencies from supporting, providing 

financial assistance for, licensing, 

permitting, or approving any activity 

that does not conform to an approved 

SIP. This provision defines ‘‘conformity 

to a SIP’’ to mean (1) conformity to the 

SIP’s purpose of eliminating or reducing 

the severity and number of NAAQS 

violations and achieving expeditious 

attainment of the NAAQS, (2) that the 

activity will not cause or contribute to 

any new violation of the NAAQS in any 

area, (3) that the activity will not 

increase the frequency or severity of any 

existing NAAQS violation in any area, 

and (4) that the activity will not delay 

timely attainment of any NAAQS or 

interim milestones. Commenters focus 

on the fourth requirement above—that 

an activity will not delay timely 

attainment of any NAAQS or any 

interim milestones—to support their 

argument that EPA’s May 2009 proposal 

is inconsistent with the CAA because it 

would allow a new or expanded 

transportation project to conform to the 

SIP if the project does not achieve 

attainment of the NAAQS. EPA 

disagrees with the commenters’ 

assertion. 

EPA first notes that two of the four 

elements in the statutory definition of 

‘‘conformity to an implementation plan’’ 

contain some redundancy. Section 

176(c)(1)(A) states that ‘‘conformity to an 

implementation plan’’ means conformity 

to the SIP’s purpose of eliminating or 

reducing the severity and number of 

NAAQS violations and achieving 

expeditious attainment of the NAAQS. 

Section 176(c)(1)(B)(iii) states that 

conformity to the SIP means that the 

transportation activity will not delay 

timely attainment of the NAAQS or any 

interim milestones. Both of these 

criteria seek to ensure attainment of the 

SIP in a timely manner—by requiring 

that projects not delay timely attainment 

or any interim milestones in any area 

and thereby ensuring expeditious 

attainment of the NAAQS. If a project 

conforms to the SIP’s purpose of 

achieving expeditious attainment of the 

NAAQS, it cannot be delaying timely 

attainment of the NAAQS, since 

‘‘expeditious attainment’’ would require 

attainment at least as early as would 

‘‘timely attainment.’’ ‘‘Expeditious’’ 

means ‘‘characterized by speed and 

efficiency,’’ whereas ‘‘timely’’ is defined 

as ‘‘before a time limit expires’’ or ‘‘done 

or happening at the appropriate or 

proper time.’’ 46 Thus, EPA is not 

reading section 176(c)(1)(B)(iii) out of 

the statute, as commenters assert, but is 

instead reading it in conjunction with a 

closely related provision which also 

addresses projects’ relationship to 

attainment of the NAAQS. 

Further, the regulatory requirements 

for hot-spot analyses meet the 

requirement that a project not delay 

timely attainment of the NAAQS or any 

interim milestones. See 40 CFR 

93.123(c). The hot-spot analysis must 

evaluate air quality concentrations 

resulting from emissions from the 

project and the future background 

pollutant concentrations. Such 

concentrations must be examined at 

receptor locations in the localized area 

substantially affected by the project. 

Future background concentrations at the 

project location are based on either 

available monitoring data near the 

project location, or when such 

information is not available, the latest 

information must be used as determined 

through the interagency consultation 

process (40 CFR 93.105(c)(1)(i)). Based 

on a review of the available data, the 

hot-spot analysis must include future 

expected air quality concentrations at 

the project location. The concentrations 

must then be compared to the NAAQS 

and the project will conform to the SIP 

only if it can be shown that the project 

does not cause or contribute to any new 

localized violations, increase the 

frequency or severity of any existing 

violations, or delay timely attainment of 

any NAAQS or any interim milestones. 

See 40 CFR 93.116(a). The fact that the 

regulations provide that these criteria 

are met if, during the time frame of the 

transportation plan, (1) no new local 

violations will be created, (2) the 

severity or number of existing violations 

will not be increased as a result of the 

project, and (3) the project has been 

included in a regional emissions 

analysis that meets applicable §§ 93.118 

and/or 93.119 requirements does not 

mean that the project may delay timely 

attainment of the NAAQS and still be 

found to conform. 

Specifically, commenters assert that 

the requirement that a project must be 

included in a regional emissions 

analysis does not suffice to ensure that 

it will not delay timely attainment of the 

NAAQS, because the regional emissions 

analysis is based on the approved SIP, 

and EPA’s SIP guidance does not 

require states to model the incremental 

impact of highway emissions in the 

ambient air near highways or to develop 

control strategies to remedy nearhighway NAAQS violations. 

Commenters assert that only if EPA 

were to modify its SIP guidance 

accordingly would it be reasonable to 

interpret section 176(c)(1)(B)(iii) as EPA 

has done in the proposed rule. 

Commenters also state that section 

176(c)(1)(B)(iii) requires some remedial 

action to be taken if a NAAQS violation 

is projected after the attainment 

deadline, even if the project itself does 

not adversely affect emissions. EPA 

disagrees. First, EPA notes that any 

comments requesting that EPA revise its 

regulations and/or policies regarding 

establishment of the PM2.5 NAAQS, 

designation of PM2.5 nonattainment 

areas and development of PM2.5 SIPs are 

beyond the scope of this rulemaking. 

Further, the requirement that a project 

is included in a regional emissions 

analysis, in conjunction with the other 

requirements of § 93.116(a) and the 

requirements of § 93.123, is sufficient to 

ensure that transportation projects do 

not delay timely attainment of the 

NAAQS as explained below. And 

finally, as described above, the DC 

Circuit has already held that a project 

need not achieve additional emissions 

reductions needed to attain the NAAQS 

in order to conform to the SIP. 

The approved SIP for a nonattainment 

area contains the control measures and 

emissions projections that demonstrate 


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47Under 40 CFR 93.123(b)(1), EPA has identified 

projects of local air quality concern that require a 

localized hot-spot analysis. These projects include 

all new or expanded highway projects that have a 

significant number of or a significant increase in 

diesel vehicles). 

attainment of the NAAQS by the 

required attainment date, including the 

motor vehicle emissions budget that 

defines the upper limit of transportation 

sector emissions above which 

attainment could be delayed. Therefore, 

a project will not delay attainment 

beyond the required date if its 

transportation emissions (along with all 

other transportation emissions) are 

included in a conformity analysis that 

meets the SIP budgets in the attainment 

year and all other future years. 

Commenters point to EPA’s statement in 

the preamble to the 2006 PM2.5 hot-spot 

rule that PM2.5 SIP modeling is unlikely 

to be performed at the level of detail 

necessary to identify PM2.5 hot-spots to 

support their assertion that EPA cannot 

rely on the regional emissions analysis 

as part of the hot-spot analysis. 

However, that statement in the 2006 

preamble is taken out of context by 

commenters. The original statement was 

part of EPA’s explanation for not 

finalizing a proposed option for which 

projects need a PM10 or PM2.5 hot-spot 

analysis (rather than how the analysis is 

actually completed). In the 2006 rule, 

EPA did not finalize the proposed 

option to require hot-spot analyses only 

in the cases where the SIP identifies 

projects of local air quality concern.47

The 2006 statement was not, as 

suggested by commenters, a judgment 

on the value of the regional emissions 

analysis that supports a conformity 

determination. EPA continues to believe 

that regional conformity analyses are 

critical to meeting all of section 

176(c)(1) requirements for project-level 

conformity determinations, in 

conjunction with hot-spot analyses of 

emissions resulting from the project in 

the local affected area along with other 

future expected emissions in that area. 

Rather, it only indicates EPA’s view that 

SIP modeling is unlikely to identify all 

locations that warrant a hot-spot 

analysis. 

Moreover, in addition to 

demonstrating that the project is 

consistent with the regional emissions 

analysis (which supports the budget), 

there can be no new local violations and 

the severity or number of existing 

violations cannot increase as a result of 

the project. In practice, EPA’s 

regulations will ensure that any project 

that creates a new violation or worsens 

an existing violation of the NAAQS in 

the local area affected by the project 

(either by increasing the number of 

violations or the severity of an existing 

violation) will not be found to conform. 

A project will be found to conform only 

if it is demonstrated that the project will 

not adversely impact air quality 

concentrations in the affected local area, 

and has been included in a regional 

emissions analysis that meets the rule’s 

conformity test requirements. Therefore, 

for the reasons explained above, EPA is 

finalizing the proposed regulations, 

which will ensure that project-level 

conformity determinations will comply 

with all the statutory criteria in section 

176(c)(1)(A) and (B). 

EPA has responded to other 

comments related to the hot-spot 

provisions at the end of this section, 

below. 

2. Requirement for No Delay in Timely 

Attainment of the NAAQS 

The provisions of today’s final rule 

clarify that a project will meet CAA 

section 176(c)(1)(B)(iii) requirements 

not to delay timely attainment as long 

as no new or worsened violations are 

predicted to occur, which is already 

required under the existing hot-spot 

requirements. While overall emissions 

can increase in a local area above those 

expected without a new project’s 

implementation, a project will not delay 

timely attainment if air quality 

concentrations continue to meet federal 

air quality NAAQS or any violations of 

the NAAQS are not worsened. 

Furthermore, in the case where the 

analysis shows that air quality 

concentrations are above the NAAQS, a 

project would not delay timely 

attainment if air quality is improved or 

unchanged from what would have 

occurred without the new project’s 

implementation. In other words, even 

where air quality concentrations are 

above the NAAQS, a project does not 

delay timely attainment if it improves 

air quality associated with a violation 

that existed prior to completion of the 

project, or does not increase such 

violation. In this case, the project also 

would still meet section 176(c)(1)(B)(i) 

and (B)(ii), in that it does not cause or 

worsen an existing violation. 

For example, suppose a hot-spot 

analysis is performed for a new highway 

project that is predicted to significantly 

increase the number of diesel trucks 

from what is expected in the local area 

without the project. A year is chosen in 

this example to analyze when peak 

emissions from the project are expected 

and future air quality is most likely to 

be impacted due to the cumulative 

impacts of the project and background 

emissions in the project area. Under the 

conformity rule, both as it existed and 

as it is amended today, the project 

would meet section 176(c)(1)(B)(iii) 

requirements not to delay timely 

attainment in the local project area as 

long as the project’s new emissions do 

not create new violations or worsen 

existing violations in the local project 

area. Such a demonstration would 

examine the total impact of the project’s 

new emissions in the context of the 

future transportation system, any 

expected growth in other emissions 

sources, and any existing or new control 

measures that are expected to impact 

the local project area. If the hot-spot 

analysis demonstrated that the proposed 

project would improve or not impact air 

quality, then timely attainment would 

also not be delayed from what would 

have occurred without the project. If a 

violation still exists with the project, but 

the project itself improves or does not 

change air quality, it does not delay 

timely attainment and it can conform. In 

contrast, if such a project increased 

emissions enough to cause a new 

violation or worsen an existing violation 

in the local project area, then the project 

would delay timely attainment, since 

worsening air quality above the NAAQS 

would impede the ability to attain in the 

local project area. In such a case, the 

project could not be found to conform 

until the new or worsened future 

violation was mitigated. 

3. Requirement for No Delay in Timely 

Attainment of Any Required Interim 

Reductions or Milestones 

Today’s final rule also ensures that a 

project would meet CAA section 

176(c)(1)(B)(iii) requirements for no 

delay in the timely attainment of any 

required interim reductions or other 

milestones. EPA interprets ‘‘any 

required interim emission reductions or 

other milestones’’ to refer to CAA 

requirements associated with reductions 

and milestones addressed by reasonable 

further progress SIPs, rather than other 

reductions required for other purposes. 

However, EPA believes there is added 

value in referencing in section 93.116(a) 

the conformity requirement that a 

project be consistent with the budgets 

and control measures in any applicable 

SIP, not just reasonable further progress 

SIPs. Therefore, the provisions of 

today’s final rule clarify that this 

requirement is satisfied in the local 

project area if a project is consistent 

with the motor vehicle emissions 

budget(s) and control measures in the 

applicable SIP or interim emission 

test(s) (in the absence of a SIP budget). 

Although such a demonstration is 

already required under the current rule, 

EPA’s reference to the requirements in 

40 CFR 93.118 and 93.119 clarify that a 

project’s emissions—when combined 


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48 In addition, the conformity rule at 40 CFR 

93.101 defines ‘‘written commitment’’ as follows: 

‘‘Written commitment for the purposes of this 

subpart means a written commitment that includes 

a description of the action to be taken; a schedule 

for the completion of the action; a demonstration 

that funding necessary to implement the action has 

been authorized by the appropriating or authorizing 

body; and an acknowledgement that the 

commitment is an enforceable obligation under the 

applicable implementation plan.’’ Since these 

obligations are ‘‘an enforceable obligation under the 

applicable implementation plan,’’ state air agencies 

will have a role in ensuring that any necessary 

measures are properly implemented and enforced. 

with all other emissions from all other 

existing and other proposed 

transportation projects—must be 

consistent with any applicable required 

interim reductions and milestones. 

Today’s final rule also supports the 

implementation of control measures that 

are relied upon in reasonable further 

progress demonstrations and could 

impact air quality in the local project 

area. Under today’s final rule, control 

measures that are relied upon for 

reasonable further progress SIPs must 

have sufficient state and local 

commitments to be included in a 

regional emissions analysis or a hot-spot 

analysis. If the implementation of a 

control measure is not assured, then 

such reductions cannot be included in 

the regional emissions analysis for the 

entire nonattainment or maintenance 

area (40 CFR 93.122(a)) or within the 

local project area considered in a hotspot analysis (40 CFR 93.123(c)(3) and 

(4)), and conformity may not be 

demonstrated for a project. EPA believes 

that these requirements also ensure that 

‘‘any required interim emissions 

reductions or other milestones’’ are not 

delayed within a local project area as a 

result of a single project’s emissions. 

For example, a project may not meet 

CAA section 176(c)(1)(B)(iii) 

requirements if SIP control measures 

were not being implemented as 

expected and as a result, a project’s 

emissions (when combined with 

expected future emissions without the 

SIP control measures) caused a new 

violation or worsened an existing 

violation in the local project area. In 

such a case, additional control measures 

as part of the conformity determination 

may be required in order to offset any 

emissions increases from a project. 

Today’s final rule also clarifies that all 

CAA section 176(c)(1)(B)(iii) 

requirements are met when air quality 

improves as a result of the project, e.g., 

an existing air quality violation that 

would have occurred without the 

project is estimated to be reduced or 

eliminated if the new project were 

implemented. EPA believes that all of 

section 176(c)(1)(B) requirements would 

be met in the local project area in such 

a case since the Act requires that 

individual projects do not worsen air 

quality or affect an area’s ability to 

attain or achieve interim requirements. 

Certainly, if air quality improves in the 

local project area with the 

implementation of a new project, EPA 

believes that timely attainment and 

required reasonable further progress 

interim requirements are not delayed. In 

fact, the opposite would be true in such 

a case, since future air quality would be 

improved and attainment possibly 

expedited from what would have 

occurred without the project’s 

implementation. 

4. Other Comments 

EPA is including responses to other 

relevant comments on this portion of 

today’s rule below. 

Comment: One commenter thought 

that based on the statutory language in 

CAA 176(c)(1)(A) and (B), promulgating 

rules that require PM2.5 emission 

reductions would be permissible and 

reasonable. Another commenter 

believed that EPA had not responded to 

the court’s remand, since it was not 

expanding on existing conformity rule 

requirements for hot-spot analyses. 

Response: As explained above, EPA 

disagrees that section 176(c)(1) requires 

projects to reduce emissions. As such, 

EPA believes its interpretation of these 

provisions is the most reasonable one. 

Hot-spot analyses in PM2.5 (and PM10) 

nonattainment and maintenance areas 

are required for transportation projects 

of local air quality concern. Such 

projects are those highway and transit 

projects that involve significant diesel 

traffic, significant increases in diesel 

traffic, or significant numbers of diesel 

vehicles congregating in one location. 

These types of projects are unlikely to 

improve air quality in and of 

themselves. 

The structure of section 176(c) 

supports EPA’s interpretation as the 

most reasonable interpretation of the 

statutory language. The conformity 

provisions of the CAA in 176(c)(1)(A) 

and (B) do not require that 

transportation activities reduce 

emissions, only that they be consistent 

with the purpose of the SIP. Only in the 

specific provision of 176(c)(3)(A)(iii) 

does the statute require transportation 

projects to ‘‘contribute to annual 

emissions reductions,’’ and this 

requirement applies to projects only in 

certain CO areas before such areas have 

a SIP, not generally to all projects. Had 

Congress intended for projects subject to 

sections 176(c)(1)(A) and (B) to 

‘‘contribute to annual emissions 

reductions,’’ it would have included 

explicit language stating so, as it did in 

section 176(c)(3). See further details in 

our general rationale earlier in this 

section. 

Comment: One commenter requested 

that EPA add language to the conformity 

rule that prescribes procedures for 

requesting assistance from the air 

quality agency in developing offsetting 

emissions reductions, to reduce air 

quality concentrations at appropriate 

receptor locations to levels that attain 

the NAAQS on or after the attainment 

deadline. 

Response: EPA does not believe 

additional language is necessary 

because existing requirements 

adequately address the state air agency’s 

involvement in developing offsetting 

measures. First, the existing regulation 

at 40 CFR 93.123(c)(4) states: ‘‘CO, PM10,

or PM2.5 mitigation or control measures 

shall be assumed in the hot-spot 

analysis only where there are written 

commitments from the project sponsor 

and/or operator to implement such 

measures, as required by § 93.125(a).’’ 48

The air quality agency as well as EPA 

has the opportunity to review any such 

written commitments during 

interagency consultation on the 

conformity determination per 40 CFR 

93.105(c). Second, if offsetting measures 

are added to the SIP, then the state air 

quality agency would have to agree on 

these measures. In addition, the 

development of offsetting emissions 

reductions would be subject to the 

public process required for a SIP 

revision. Third, in the case where a new 

transportation control measure (TCM) is 

to be added to the SIP without a full SIP 

revision, the CAA requires the TCM to 

be developed through a collaborative 

process that includes the state air 

quality agency; in addition, the state air 

quality agency as well as EPA must 

concur before such a TCM is added to 

the SIP. See EPA’s guidance, entitled, 

‘‘Guidance for Implementing the Clean 

Air Act Section 176(c)(8) Transportation 

Control Measure Substitution and 

Addition Provision,’’ found on EPA’s 

Web site at: http://www.epa.gov/otaq/ 

stateresources/transconf/policy/ 

420b09002.pdf. 

Comment: One commenter thought 

the regulations at 40 CFR 93.116(a) and 

93.123 are unclear regarding the 

specifics of performing a PM hot-spot 

analysis, including whether the 

conformity rule requires a comparison 

of emissions from the build case with 

the emissions from the no-build case in 

the same future year, or whether it 

allows a comparison of the build case 

with emissions in the current year as the 

baseline. The commenter was concerned 

that if the analysis is based on a 

comparison of the build case for a future 


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year with current emissions, a project 

could conform even if it adds more 

vehicle trips to the project location, 

because the build analysis would 

include the effect of new engine control 

technologies and fleet turnover. The 

commenter believes that the analysis 

should examine the impacts of the 

project itself. Therefore, the commenter 

urged that the rule be clarified to require 

an estimate of future peak year 

emissions using a build/no-build 

analysis, which the commenter asserted 

would provide a lawful basis for 

assessing the impact of emissions from 

a proposed project. 

Response: This comment is beyond 

the scope of this rulemaking. For 

purposes of EPA’s hot-spot regulations, 

EPA is only addressing in today’s rule 

the specific issue that was remanded by 

the Court in December 2007, i.e., 

whether CAA section 176(c)(1)(B)(iii) 

applies in the local area affected by a 

project. As stated in the May 2009 

proposal, EPA did not propose or seek 

public comment on any other aspect of 

EPA’s preexisting rules for performing 

hot-spot analyses under 40 CFR 93.123 

or any other parts of the conformity 

rule. 

In addition, EPA has already 

addressed how hot-spot analyses are to 

be conducted to avoid the situation 

described by the commenter. In the 

original conformity rule, EPA stated its 

intentions for applying the hot-spot 

requirement—‘‘that the hot-spot analysis 

compare concentrations with and 

without the project based on modeling 

of conditions in the analysis year.’’ (58 

FR 62212). The July 2004 final rule 

clarified the horizon years for hot-spot 

analyses. In this rule, EPA stated that 

‘‘[t]o ensure that the requirement for hotspot analysis is being satisfied, areas 

should examine the year(s) within the 

transportation plan or regional 

emissions analysis, as appropriate, 

during which peak emissions from the 

project are expected and a new violation 

or worsening of an existing violation 

would most likely occur due to the 

cumulative impacts of the project and 

background regional emissions in the 

project area.’’ See 69 FR 40056–58 for 

more details on this rulemaking. 

Furthermore, EPA agrees that it would 

be inappropriate to ignore the future air 

quality impacts from building a 

proposed project. As stated above, 

EPA’s rule requires that in the future 

year(s) where emissions are expected to 

be the highest, the concentrations of the 

pollutant that result from the project’s 

emissions in combination with 

background emissions from other 

sources are compared to the NAAQS. 

However, this analysis is performed by 

examining future air quality impacts 

from a project, rather than comparing 

emissions from the project in the future 

to emissions in a baseline year. EPA 

strongly disagrees that the current rule 

can be interpreted in this way. An 

analysis under the rule does provide a 

lawful basis for assessing the impact of 

emissions from a proposed project, 

because it compares resulting air quality 

concentrations to the NAAQS, which by 

law are established by EPA through 

rulemaking. 

As stated above, in the case where the 

analysis shows that the air quality 

concentrations are greater than the 

NAAQS, the project may still be able to 

conform. If building the project leads to 

improved air quality concentrations 

over not building the project, then the 

project could still be found to conform, 

even if the concentrations are above the 

NAAQS. In this case, a build/no-build 

analysis would show that the project is 

helping to reduce concentrations, and 

improve air quality by reducing a future 

violation. In this case, the project 

neither creates a new violation nor 

worsens an existing violation, nor does 

it delay timely attainment. 

Last, it is entirely appropriate that a 

hot-spot analysis include the effects of 

new technologies and fleet turnover that 

is expected to occur in a future analysis 

year. The conformity rule has always 

allowed the future effects of federal 

vehicle emissions standards, fleet 

turnover, fuel programs, and other 

control measures to be reflected in hotspot analyses when they are assured to 

occur, because including such effects 

provides a reasonable estimate of future 

emissions that is more accurate than not 

including such effects. 

Comment: One commenter opined 

that off-road emissions that result from 

a transportation project being built 

should be included in the hot-spot 

analysis as part of the background 

emissions, because the conformity 

regulations at 40 CFR 93.123(c) require 

them to be included: ‘‘[e]stimated 

pollutant concentrations must be based 

in the total emissions burden which 

may result from the implementation of 

the project.’’ The commenter asserted 

that a highway project that facilitates 

additional diesel vehicles such as 

ocean-going vessels, locomotives, 

harborcraft, and cargo-handling 

equipment cannot ignore these 

significant sources of emissions that 

affect the air quality at the location of 

the project. 

Response: This comment is outside 

the scope of today’s rulemaking for the 

reasons discussed above. However, EPA 

notes that it agrees with this comment. 

As the commenter points out, the 

regulations at 40 CFR 93.123(c)(1) state: 

‘‘Estimated pollutant concentrations 

must be based on the total emissions 

burden which may result from the 

implementation of the project, summed 

together with future background 

concentrations.’’ EPA agrees that if a 

highway project will facilitate 

additional diesel ships or locomotives, 

these additional non-road emissions 

must be included as part of the 

background concentrations in the hotspot analysis. The current conformity 

rule also requires hot-spot analyses to 

consider any emissions that are already 

expected to occur from other sources in 

the local project area, in addition to any 

emissions created by the project being 

built. 

Comment: One commenter suggested 

that hot-spot analyses should apply to 

existing projects, not just new projects, 

and that the language of CAA section 

176(c) would support ‘‘an ongoing duty’’ 

to ensure compliance with the hot-spot 

rule. To the extent that the federal 

government ‘‘engage[s] in’’ or ‘‘supports’’ 

a facility, the commenter believed that 

a hot-spot analysis is required. For 

example, when the government 

provides funds for maintenance and 

repair of freight facilities, the 

commenter believed there should be an 

ongoing requirement to perform a hotspot analysis. 

Response: This comment is outside 

the scope of today’s action. EPA did not 

propose or seek comment on any 

revision to the hot-spot regulations 

addressing when hot-spot analyses are 

required. Since the original 1993 

transportation conformity rule, EPA’s 

hot-spot requirements have applied only 

to those projects that require projectlevel conformity determinations under 

40 CFR 93.102(a) and 93.104(d), which 

are those new non-exempt highway and 

transit projects that receive FHWA or 

FTA funding or approval. After that 

point, conformity of a project does not 

need to be redetermined unless one of 

three things occur: (1) The project’s 

design concept and scope significantly 

changes; (2) three years elapse since the 

most recent major step to advance the 

project; or (3) a supplemental 

environmental document has been 

initiated for air quality purposes (40 

CFR 93.104(d)). EPA has previously 

concluded that a new project-level 

conformity determination is warranted 

in these cases. Barring one of these 

cases, it is reasonable to conclude that 

conformity continues to be 

demonstrated, based on both the initial 

project-level conformity determination 

as well as the periodic regional 

conformity determination needed for 

the transportation plan and TIP, which 


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includes the project. Today’s final rule 

addresses none of these requirements. 

Comment: One commenter stated that 

the proposed rule is inconsistent with 

EPA’s definition for ‘‘hot-spot analysis’’ 

and the CAA because the proposed rule 

fails to require a comparison of 

localized PM2.5 concentrations to the 

NAAQS. The commenter opines that 

EPA’s regulatory definition is consistent 

with the statutory text but the proposed 

rule is not in that it fails to expressly 

require that, where emissions from a 

highway project subject to hot-spot 

review would cause or contribute to 

NAAQS violations after the attainment 

deadline, approval of the project must 

be prohibited unless some remedial 

action is taken to avoid the NAAQS 

violation after the attainment deadline. 

The same commenter also stated that 

EPA’s proposal is not consistent with 

the CAA because it would allow a 

project to conform even if emissions are 

maintained at levels that will continue 

to cause NAAQS violations after the 

statutory deadline. 

Response: EPA disagrees with this 

commenter and the description of the 

May 2009 proposal. Today’s final rule 

does require a comparison of localized 

pollutant concentrations to the NAAQS. 

By requiring a demonstration that no 

new local violations are created and no 

existing violations are worsened, the 

regulation does require a comparison to 

the NAAQS. In addition, today’s final 

rule would not result in the outcome in 

the example provided by commenters. 

As stated earlier, a project could not be 

found to conform if its emissions caused 

or contributed to a future NAAQS 

violation. 

In the commenter’s second example, 

the project could be found to conform, 

since the project’s emissions would not 

have caused or worsened a NAAQS 

violation. If a hot-spot analysis shows 

that air quality concentration levels 

would be the same with and without a 

project, then such a project would not 

be ‘maintaining’ any NAAQS violation, 

as suggested by the commenter. Instead, 

such a hot-spot analysis would show 

that a project is not the cause or 

contributor to the local area’s air quality 

problem, and consequently, the project 

would not be delaying timely 

attainment. See other parts of today’s 

final rule preamble for rationale on 

similar comments. 

Comment: One commenter requested 

that EPA add a definition to the 

conformity rule for the term ‘‘delay 

timely attainment.’’ The commenter 

requested that the term be defined as 

follows: If emissions from a project are 

expected to cause or contribute to 

concentrations that are greater than the 

NAAQS at appropriate receptor 

locations after the attainment deadline, 

the project would fail to meet CAA 

176(c)(1)(B)(iii). 

Response: EPA does not believe it is 

necessary to promulgate a separate 

regulatory definition of the term ‘‘delay 

timely attainment’’ in section 93.101 of 

the conformity rule. Section 93.116(a) of 

today’s final rule and section 93.123(c) 

of the existing conformity rule include 

this regulatory text, and the discussion 

in this preamble and earlier preambles 

to transportation conformity regulations 

adequately explain the meaning of 

‘‘delay timely attainment’’ in the context 

of section 176(c)(1)(B)(iii), including 

how the hot-spot analysis must comply 

with that provision. 

Comment: One commenter requested 

that EPA define ‘‘local area’’ for hot-spot 

analysis purposes, because neither the 

proposed nor existing conformity rule 

clearly defines it. The commenter 

opined that depending upon the 

definition, the results of the analysis 

might be different. As an example, the 

commenter indicated that a project such 

as a bus terminal might result in 

increased emissions in the immediate 

area (although not enough to violate 

other portions of section 176(c)(1)(B)), 

but may be part of a larger group of 

projects that would reduce emissions 

overall in a larger area. 

Response: EPA agrees that PM hotspot analyses under the conformity rule 

must examine the air quality impacts of 

the PM10 and PM2.5 NAAQS, including 

the area immediately surrounding the 

project. In developing the March 2006 

final PM hot-spot rule, EPA completed 

a thorough review of more than 70 

studies representing a cross-section of 

available studies looking at particle 

concentrations near roadways and 

transit projects (71 FR 12472–12474). 

Many of these studies were completed 

in the types of local communities cited 

by the commenter. 

However, EPA is not defining ‘‘local 

area’’ in this final rule because the 

existing conformity rule, along with 

previous conformity preambles, provide 

the necessary information for hot-spot 

analyses. First, the rule’s ‘‘hot-spot 

analysis’’ provisions are applied at a 

local level to an individual ‘‘highway 

project’’ or ‘‘transit project,’’ and the rule 

defines all three of these terms in detail 

(see 40 CFR 93.101). As a result, the hotspot requirements for individual 

projects in conformity rule sections 

93.116 and 93.123 are applied within 

the local project area. Another example 

is the rule’s definition of ‘‘cause or 

contribute to a new violation,’’ which 

includes the phrase about this 

requirement being met ‘‘in an area 

substantially affected by the project.’’ 

EPA believes that all of the conformity 

rule’s hot-spot provisions provide 

adequate information regarding what is 

a ‘‘local area,’’ and a separate ‘‘local area’’ 

definition is not necessary or required 

by the December 2007 court remand. 

EPA does not believe that ‘‘local area’’ 

can be more specifically defined and 

still be appropriate for all projects, 

because projects where a hot-spot 

analysis is needed can differ in type, 

location, scale, scope, and neighboring 

populations. EPA believes that the 

existing regulation allows the 

appropriate local area to be determined 

in a hot-spot analysis. 

EPA also notes that in the 

commenter’s example, a bus terminal 

increases emissions in the immediate 

area but does not violate other portions 

of section 176(c)(1)(B), i.e., this project 

increases emissions but would not 

create a new violation or worsen an 

existing NAAQS violation. Therefore, 

this project could be found to conform 

under the PM hot-spot conformity rules. 

Comment: One commenter requested 

that EPA define ‘‘appropriate receptor 

location’’ in section 93.123(c)(1) of the 

conformity rule to be ‘‘locations near the 

project where the public has daily 

access and where exposure risks will be 

greatest with regard to the frequency or 

severity.’’ The commenter stated that the 

rule should clarify that receptor or 

monitor locations should not be located 

outside the zone of observed highway 

impacts because at those distances no 

difference would be detected regardless 

of how many additional vehicles are 

added. The commenter cited examples 

of past PM hot-spot analyses where 

emissions impacts were examined at 

monitors or locations that were a mile 

and a half or more from the highway or 

from the residential and school facilities 

adjacent to the proposed project. The 

commenter stated that in both cases, 

evidence was submitted showing that 

highway emissions decrease to the level 

of regional background within the first 

300 meters. 

In addition, this and another 

commenter provided EPA with recent 

studies and data illustrating the air 

quality impacts of highways in the nearhighway environment, and with data 

tallying the millions of people who live 

within this range as well as the number 

of schools located within it. 

Response: EPA appreciates the data 

that commenters provided, and agrees 

with commenters that hot-spot analyses 

are important to ensure that public 

health is protected. As noted in the 

previous response, EPA finalized the 

PM10 and PM2.5 hot-spot requirements 

based on the type of information 


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49EPA will provide opportunity for public 

comment on the PM quantitative hot-spot guidance 

according to the terms of a settlement agreement 

with Environmental Defense, Natural Resources 

Defense Council, and Sierra Club. Refer to the June 

22, 2007 ‘‘Notice of proposed settlement agreement; 

request for public comment’’ at 72 FR 34460. 

submitted by commenters (71 FR 

12472–12474). However, the location of 

modeling receptors, which is addressed 

in 40 CFR 93.123(c), is outside the scope 

of today’s final rule. 

EPA also notes that the U.S. District 

Court in Maryland has upheld the 

appropriateness of one of the PM 

qualitative hot-spot analyses cited by 

the commenter (Audubon Naturalist 

Society of the Central Atlantic States, 

Inc., et al v. USDOT, et al., 524 

F.Supp.2d 642 (Md. 2007), appeal 

dismissed without decision 

Environmental Defense, et al. v. 

USDOT, et al., No. 08–1107 (4th Cir., 

dismissed Nov. 17. 2008)). 

EPA intends to describe appropriate 

receptor locations in its forthcoming 

quantitative PM hot-spot guidance, 

which is required under 40 CFR 

93.123(b)(4). Interested parties will have 

an opportunity to comment on this 

document before it is finalized.49

Comment: One commenter 

recommended that EPA require projects 

to reduce the severity and number of 

local 2006 PM2.5 NAAQS violations as a 

way to reduce black carbon. This 

commenter noted that in EPA’s recent 

proposed endangerment finding for 

greenhouse gases, EPA explained that it 

did not include black carbon because 

EPA is addressing black carbon through 

its review of the primary and secondary 

PM NAAQS. This commenter cited a 

large body of new science explaining 

black carbon’s climate forcing effect and 

impacts on sensitive ecosystems, and 

believed that this rule should include 

some specific requirements for black 

carbon. 

Response: Transportation conformity 

applies only to transportation-related 

criteria pollutants for which a NAAQS 

is established and their precursor 

pollutants as described in 40 CFR 

93.102(b) of the regulation. There is no 

NAAQS specifically for black carbon, 

therefore EPA lacks authority to require 

conformity analysis specifically for 

black carbon. To the extent that black 

carbon is a component of PM2.5 (as 

defined by 40 CFR 93.102(b)(1) and 

EPA’s rulemakings for the development 

of any PM2.5 NAAQS), it is included as 

part of any conformity analysis for 

PM2.5.

X. Statutory and Executive Order 

Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review 

This action is not a ‘‘significant 

regulatory action’’ under the terms of 

Executive Order (EO) 12866, (58 FR 

51735; October 4, 1993) and is therefore 

not subject to review under the EO. 

B. Paperwork Reduction Act 

This action does not impose any new 

information collection burden. The 

information collection requirements of 

EPA’s existing transportation 

conformity regulations and the 

proposed revisions in today’s action are 

already covered by EPA information 

collection request (ICR) entitled, 

‘‘Transportation Conformity 

Determinations for Federally Funded 

and Approved Transportation Plans, 

Programs and Projects.’’ The Office of 

Management and Budget (OMB) has 

previously approved the information 

collection requirements contained in the 

existing regulations at 40 CFR Part 93 

under the provisions of the Paperwork 

Reduction Act, 44 U.S.C. 3501 et seq. 

and has assigned OMB control number 

2060–0561. The OMB control numbers 

for EPA’s regulations in 40 CFR are 

listed in 40 CFR Part 9. 

C. Regulatory Flexibility Act 

The Regulatory Flexibility Act (RFA) 

generally requires an Agency to prepare 

a regulatory flexibility analysis of rules 

subject to notice and comment 

rulemaking requirements under the 

Administrative Procedure Act or any 

other statute unless the Agency certifies 

that the rule will not have a significant 

economic impact on a substantial 

number of small entities. Small entities 

include small businesses, small not-forprofit organizations and small 

government jurisdictions. 

For purposes of assessing the impacts 

of today’s rule on small entities, small 

entity is defined as: (1) A small business 

as defined by the Small Business 

Administration’s (SBA) regulations at 13 

CFR 121.201; (2) a small governmental 

jurisdiction that is a government of a 

city, county, town, school district or 

special district with a population of less 

than 50,000; and (3) a small 

organization that is any not-for-profit 

enterprise that is independently owned 

and operated and is not dominant in its 

field. 

After considering the economic 

impacts of today’s final rule on small 

entities, I certify that this action will not 

have a significant economic impact on 

a substantial number of small entities. 

This regulation directly affects federal 

agencies and metropolitan planning 

organizations that, by definition, are 

designated under federal transportation 

laws only for metropolitan areas with a 

population of at least 50,000. These 

organizations do not constitute small 

entities within the meaning of the 

Regulatory Flexibility Act. 

D. Unfunded Mandates Reform Act 

This rule does not contain a Federal 

mandate that may result in expenditures 

of $100 million or more for State, local, 

and tribal governments, in the aggregate, 

or the private sector in any one year. 

The purpose of this final rule is to 

amend the conformity rule to clarify 

how certain highway and transit 

projects meet statutory conformity 

requirements for particulate matter in 

response to a December 2007 court 

ruling, and to update the regulation to 

accommodate revisions to the PM10 and 

PM2.5 NAAQS. This final rule merely 

implements already established law that 

imposes conformity requirements and 

does not itself impose requirements that 

may result in expenditures of $100 

million or more in any year. Thus, 

today’s final rule is not subject to the 

requirements of sections 202 and 205 of 

the UMRA. 

This rule is also not subject to the 

requirements of section 203 of UMRA 

because it contains no regulatory 

requirements that might significantly or 

uniquely affect small governments. This 

rule will not significantly or uniquely 

impact small governments because it 

directly affects federal agencies and 

metropolitan planning organizations 

that, by definition, are designated under 

federal transportation laws only for 

metropolitan areas with a population of 

at least 50,000. 

E. Executive Order 13132: Federalism 

This final rule does not have 

federalism implications. It will not have 

substantial direct effects on states, on 

the relationship between the national 

government and states, or on the 

distribution of power and 

responsibilities among the various 

levels of government, as specified in 

Executive Order 13132. The CAA 

requires conformity to apply in certain 

nonattainment and maintenance areas 

as a matter of law, and this action 

merely establishes and revises 

procedures for transportation planning 

entities in subject areas to follow in 

meeting their existing statutory 

obligations. Thus, Executive Order 

13132 does not apply to this rule. 


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F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

This action does not have tribal 

implications, as specified in Executive 

Order 13175 (65 FR 67249, November 9, 

2000). The CAA requires transportation 

conformity to apply in any area that is 

designated nonattainment or 

maintenance by EPA. This rule amends 

the conformity rule to clarify how 

certain highway and transit projects 

meet statutory conformity requirements 

for particulate matter in response to a 

December 2007 court ruling, and 

updates the conformity rule to 

accommodate revisions to the PM10 and 

PM2.5 NAAQS. Because today’s 

amendments to the conformity rule do 

not significantly or uniquely affect the 

communities of Indian tribal 

governments, Executive Order 13175 

does not apply to this action. 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

and Safety Risks 

This final rule is not subject to 

Executive Order 13045 62 FR 19885, 

April 23, 1997) because it is not 

economically significant as defined in 

Executive Order 12866, and because the 

Agency does not believe the 

environmental health or safety risks 

addressed by this action present a 

disproportionate risk to children. 

H. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

This action is not a ‘‘significant energy 

action’’ as defined in Executive Order 

13211 (66 FR 18355 (May 22, 2001)), 

because it is not likely to have a 

significant adverse effect on the supply, 

distribution, or use of energy. It does not 

create a serious inconsistency or 

otherwise interfere with an action taken 

or planned by another agency regarding 

energy. Further, this rule is not likely to 

have any adverse energy effects because 

it does not raise novel legal or policy 

issues adversely affecting the supply, 

distribution or use of energy arising out 

of legal mandates, the President’s 

priorities, or the principles set forth in 

Executive Orders 12866 and 13211. 

I. National Technology Transfer and 

Advancement Act 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act of 1995 (‘‘NTTAA’’), Public Law 

104–113, section 12(d) (15 U.S.C. 272 

note) directs EPA to use voluntary 

consensus standards in its regulatory 

activities unless to do so would be 

inconsistent with applicable law or 

otherwise impractical. Voluntary 

consensus standards are technical 

standards (e.g., material specifications, 

test methods, sampling procedures, and 

business practices) that are developed or 

adopted by voluntary consensus 

standards bodies. NTTAA directs EPA 

to provide Congress, through OMB, 

explanations when the Agency decides 

not to use available and applicable 

voluntary consensus standards. 

This action does not involve technical 

standards. Therefore, EPA did not 

consider the use of any voluntary 

consensus standards. 

J. Executive Order 12898: Federal 

Actions To Address Environmental 

Justice in Minority Populations and 

Low-Income Populations 

Executive Order (EO) 12898 (59 FR 

7629 (Feb. 16, 1994)) establishes federal 

executive policy on environmental 

justice. Its main provision directs 

federal agencies, to the greatest extent 

practicable and permitted by law, to 

make environmental justice part of their 

mission by identifying and addressing, 

as appropriate, disproportionately high 

and adverse human health or 

environmental effects of their programs, 

policies, and activities on minority 

populations and low-income 

populations in the United States. 

EPA has determined that this final 

rule will not have disproportionately 

high and adverse human health or 

environmental effects on minority or 

low-income populations because it 

increases the level of environmental 

protection for all affected populations 

without having any disproportionately 

high and adverse human health or 

environmental effects on any 

population, including any minority or 

low-income population. This final rule 

simply amends the conformity rule to 

clarify how certain highway and transit 

projects meet statutory requirements for 

particulate matter in response to a 

December 2007 court ruling, and 

updates the conformity rule to 

accommodate revisions to the PM10 and 

PM2.5 NAAQS. 

K. Determination Under Section 307(d) 

Pursuant to CAA Section 307(d)(1)(U), 

the Administrator determines that this 

action is subject to the provisions of 

section 307(d). Section 307(d)(1)(U) 

provides that the provisions of section 

307(d) apply to ‘‘such other actions as 

the Administrator may determine.’’ 

L. Congressional Review Act 

The Congressional Review Act, 5 

U.S.C. 801 et seq., as added by the Small 

Business Regulatory Enforcement 

Fairness Act of 1996, generally provides 

that before a rule may take effect, the 

agency promulgating the rule must 

submit a rule report, which includes a 

copy of the rule, to each House of the 

Congress and to the Comptroller General 

of the United States prior to publication 

of the rule in the Federal Register. A 

major rule cannot take effect until 60 

days after it is published in the Federal 

Register. This action Transportation 

Conformity Rule PM2.5 and PM10

Amendments 

Page 134 of 145 is not a ‘‘major rule’’ 

as defined by 5 U.S.C. 804(2). This rule 

will be effective April 23, 2010. 

List of Subjects in 40 CFR Part 93 

Administrative practice and 

procedure, Air pollution control, Carbon 

monoxide, Clean Air Act, 

Environmental protection, Highways 

and roads, Intergovernmental relations, 

Mass transportation, Nitrogen dioxide, 

Ozone, Particulate matter, 

Transportation, Volatile organic 

compounds. 

Dated: March 10, 2010. 

Lisa P. Jackson, 

Administrator. 

■ For the reasons set out in the 

preamble, 40 CFR part 93 is amended as 

follows: 

PART 93—[AMENDED] 

■ 1. The authority citation for part 93 

continues to read as follows: 

Authority: 42 U.S.C. 7401–7671q. 

■ 2. Section 93.101 is amended as 

follows: 

■ a. By removing the definitions for 

‘‘1-hour ozone NAAQS’’ and ‘‘8-hour 

ozone NAAQS’’; and 

■ b. By revising the definition of 

‘‘National ambient air quality standards 

(NAAQS)’’. 

§ 93.101 Definitions. 

* * * * * 

National ambient air quality 

standards (NAAQS) are those standards 

established pursuant to section 109 of 

the CAA. 

(1) 1-hour ozone NAAQS means the 1- 

hour ozone national ambient air quality 

standard codified at 40 CFR 50.9. 

(2) 8-hour ozone NAAQS means the 8- 

hour ozone national ambient air quality 

standard codified at 40 CFR 50.10. 

(3) 24-hour PM10 NAAQS means the 

24-hour PM10 national ambient air 

quality standard codified at 40 CFR 

50.6. 

(4) 1997 PM2.5 NAAQS means the 

PM2.5 national ambient air quality 

standards codified at 40 CFR 50.7. 

(5) 2006 PM2.5 NAAQS means the 24- 

hour PM2.5 national ambient air quality 

standard codified at 40 CFR 50.13. 


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(6) Annual PM10 NAAQS means the 

annual PM10 national ambient air 

quality standard that EPA revoked on 

December 18, 2006. 

* * * * * 

§ 93.105 [Amended] 

■ 3. Section 93.105 is amended in 

paragraph (c)(1)(vi) by 

removing the citation 

‘‘§ 93.109(l)(2)(iii)’’ and adding in its 

place ‘‘§ 93.109(n)(2)(iii)’’. 

■ 4. Section 93.109 is amended as 

follows: 

■ a. In paragraph (b): 

■ i. By removing the citation ‘‘(c) 

through (i)’’ and adding in its place the 

citation ‘‘(c) through (k)’’; 

■ ii. By removing the reference ‘‘(j)’’ and 

adding in its place ‘‘(l)’’; 

■ iii. By removing the reference ‘‘(k)’’ 

from the fourth sentence and adding in 

its place ‘‘(m)’’; 

■ iv. By removing the reference ‘‘(l)’’ 

from the fifth sentence and adding in its 

place ‘‘(n)’’; 

■ b. By revising paragraph (g)(2) 

introductory text; 

■ c. By redesignating paragraph (g)(3) as 

(g)(4); 

■ d. By adding new paragraph (g)(3); 

■ e. By revising the heading of 

paragraph (i); 

■ f. By adding the words ‘‘such 1997’’ 

before the words ‘‘PM2.5 nonattainment 

or maintenance areas’’ in 

paragraph(i)(1); 

■ g. By adding the words ‘‘such 1997’’ 

before the words ‘‘PM2.5 nonattainment 

and maintenance areas’’ in paragraph (i) 

introductory text and paragraph (i)(2) 

introductory text; 

■ h. By adding the words ‘‘such 1997’’ 

before the words ‘‘PM2.5 nonattainment 

areas’’ in paragraph (i)(3); 

■ i. By redesignating paragraphs (j), (k), 

and (l) as (l), (m), and (n), respectively; 

■ j. In newly designated paragraph 

(n)(2) introductory text by removing the 

citation ‘‘(c) through (k)’’ and adding in 

its place the citation ‘‘(c) through (m)’’; 

■ k. In newly designated paragraph 

(n)(2)(iii): 

■ i. By removing the citation ‘‘(l)(2)(ii)’’ 

and adding in its place the citation 

‘‘(n)(2)(ii)’’; 

■ ii. By removing the citation 

‘‘(l)(2)(ii)(C)’’ and adding in its place the 

citation ‘‘(n)(2)(ii)(C)’’; 

■ l. By adding new paragraphs (j) and 

(k). 

§ 93.109 Criteria and procedures for 

determining conformity of transportation 

plans, programs, and projects: General. 

* * * * * 

(g) * * * 

(2) In PM10 nonattainment and 

maintenance areas where a budget is 

submitted for the 24-hour PM10 NAAQS, 

the budget test must be satisfied as 

required by § 93.118 for conformity 

determinations made on or after: 

* * * * * 

(3) Prior to paragraph (g)(2) of this 

section applying, the budget test must 

be satisfied as required by § 93.118 

using the approved or adequate motor 

vehicle emissions budget established for 

the revoked annual PM10 NAAQS, if 

such a budget exists. 

* * * * * 

(i) 1997 PM2.5 NAAQS nonattainment 

and maintenance areas. * * * 

(j) 2006 PM2.5 NAAQS nonattainment 

and maintenance areas without 1997 

PM2.5 NAAQS motor vehicle emissions 

budgets for any portion of the 2006 

PM2.5 NAAQS area. In addition to the 

criteria listed in Table 1 in paragraph (b) 

of this section that are required to be 

satisfied at all times, in such 2006 PM2.5

nonattainment and maintenance areas 

conformity determinations must include 

a demonstration that the budget and/or 

interim emissions tests are satisfied as 

described in the following: 

(1) FHWA/FTA projects in such PM2.5

nonattainment and maintenance areas 

must satisfy the appropriate hot-spot 

test required by § 93.116(a). 

(2) In such PM2.5 nonattainment and 

maintenance areas the budget test must 

be satisfied as required by § 93.118 for 

conformity determinations made on or 

after: 

(i) The effective date of EPA’s finding 

that a motor vehicle emissions budget in 

a submitted control strategy 

implementation plan revision or 

maintenance plan for the 2006 PM2.5

NAAQS is adequate for transportation 

conformity purposes; 

(ii) The publication date of EPA’s 

approval of such a budget in the Federal 

Register; or 

(iii) The effective date of EPA’s 

approval of such a budget in the Federal 

Register, if such approval is completed 

through direct final rulemaking. 

(3) In such PM2.5 nonattainment areas 

the interim emissions tests must be 

satisfied as required by § 93.119 for 

conformity determinations made if there 

is no approved motor vehicle emissions 

budget from an applicable 

implementation plan for the 2006 PM2.5

NAAQS and no adequate motor vehicle 

emissions budget from a submitted 

control strategy implementation plan 

revision or maintenance plan for the 

2006 PM2.5 NAAQS. 

(k) 2006 PM2.5 NAAQS nonattainment 

and maintenance areas with motor 

vehicle emissions budgets for the 1997 

PM2.5 NAAQS that cover all or a portion 

of the 2006 PM2.5 nonattainment area. 

In addition to the criteria listed in Table 

1 in paragraph (b) of this section that are 

required to be satisfied at all times, in 

such 2006 PM2.5 nonattainment and 

maintenance areas conformity 

determinations must include a 

demonstration that the budget and/or 

interim emissions tests are satisfied as 

described in the following: 

(1) FHWA/FTA projects in such PM2.5

nonattainment and maintenance areas 

must satisfy the appropriate hot-spot 

test required by § 93.116(a). 

(2) In such PM2.5 nonattainment and 

maintenance areas the budget test must 

be satisfied as required by § 93.118 for 

conformity determinations made on or 

after: 

(i) The effective date of EPA’s finding 

that a motor vehicle emissions budget in 

a submitted control strategy 

implementation plan revision or 

maintenance plan for the 2006 PM2.5

NAAQS is adequate for transportation 

conformity purposes; 

(ii) The publication date of EPA’s 

approval of such a budget in the Federal 

Register; or 

(iii) The effective date of EPA’s 

approval of such a budget in the Federal 

Register, if such approval is completed 

through direct final rulemaking. 

(3) Prior to paragraph (k)(2) of this 

section applying, the following test(s) 

must be satisfied: 

(i) If the 2006 PM2.5 nonattainment 

area covers the same geographic area as 

the 1997 PM2.5 nonattainment or 

maintenance area(s), the budget test as 

required by § 93.118 using the approved 

or adequate motor vehicle emissions 

budgets in the 1997 PM2.5 applicable 

implementation plan or implementation 

plan submission; 

(ii) If the 2006 PM2.5 nonattainment 

area covers a smaller geographic area 

within the 1997 PM2.5 nonattainment or 

maintenance area(s), the budget test as 

required by § 93.118 for either: 

(A) The 2006 PM2.5 nonattainment 

area using corresponding portion(s) of 

the approved or adequate motor vehicle 

emissions budgets in the 1997 PM2.5

applicable implementation plan or 

implementation plan submission where 

such portion(s) can reasonably be 

identified through the interagency 

consultation process required by 

§ 93.105; or 

(B) The 1997 PM2.5 nonattainment 

area using the approved or adequate 

motor vehicle emissions budgets in the 

1997 PM2.5 applicable implementation 

plan or implementation plan 

submission. If additional emissions 

reductions are necessary to meet the 

budget test for the 2006 PM2.5 NAAQS 

in such cases, these emissions 


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reductions must come from within the 

2006 PM2.5 nonattainment area; 

(iii) If the 2006 PM2.5 nonattainment 

area covers a larger geographic area and 

encompasses the entire 1997 PM2.5

nonattainment or maintenance area(s): 

(A) The budget test as required by 

§ 93.118 for the portion of the 2006 

PM2.5 nonattainment area covered by the 

approved or adequate motor vehicle 

emissions budgets in the 1997 PM2.5

applicable implementation plan or 

implementation plan submission; and 

the interim emissions tests as required 

by § 93.119 for either: the portion of the 

2006 PM2.5 nonattainment area not 

covered by the approved or adequate 

budgets in the 1997 PM2.5

implementation plan, the entire 2006 

PM2.5 nonattainment area, or the entire 

portion of the 2006 PM2.5 nonattainment 

area within an individual state, in the 

case where separate 1997 PM2.5 SIP 

budgets are established for each state of 

a multi-state 1997 PM2.5 nonattainment 

or maintenance area; or 

(B) The budget test as required by 

§ 93.118 for the entire 2006 PM2.5

nonattainment area using the approved 

or adequate motor vehicle emissions 

budgets in the applicable 1997 PM2.5

implementation plan or implementation 

plan submission. 

(iv) If the 2006 PM2.5 nonattainment 

area partially covers a 1997 PM2.5

nonattainment or maintenance area(s): 

(A) The budget test as required by 

§ 93.118 for the portion of the 2006 

PM2.5 nonattainment area covered by the 

corresponding portion of the approved 

or adequate motor vehicle emissions 

budgets in the 1997 PM2.5 applicable 

implementation plan or implementation 

plan submission where they can be 

reasonably identified through the 

interagency consultation process 

required by § 93.105; and 

(B) The interim emissions tests as 

required by § 93.119, when applicable, 

for either: The portion of the 2006 PM2.5

nonattainment area not covered by the 

approved or adequate budgets in the 

1997 PM2.5 implementation plan, the 

entire 2006 PM2.5 nonattainment area, or 

the entire portion of the 2006 PM2.5

nonattainment area within an 

individual state, in the case where 

separate 1997 PM2.5 SIP budgets are 

established for each state in a multistate 1997 PM2.5 nonattainment or 

maintenance area. 

* * * * * 

■ 5. Section 93.116 is amended by 

revising paragraph (a) to read as follows: 

§ 93.116 Criteria and procedures: 

Localized CO, PM10, and PM2.5 violations 

(hot-spots). 

(a) This paragraph applies at all times. 

The FHWA/FTA project must not cause 

or contribute to any new localized CO, 

PM10, and/or PM2.5 violations, increase 

the frequency or severity of any existing 

CO, PM10, and/or PM2.5 violations, or 

delay timely attainment of any NAAQS 

or any required interim emission 

reductions or other milestones in CO, 

PM10, and PM2.5 nonattainment and 

maintenance areas. This criterion is 

satisfied without a hot-spot analysis in 

PM10 and PM2.5 nonattainment and 

maintenance areas for FHWA/FTA 

projects that are not identified in 

§ 93.123(b)(1). This criterion is satisfied 

for all other FHWA/FTA projects in CO, 

PM10 and PM2.5 nonattainment and 

maintenance areas if it is demonstrated 

that during the time frame of the 

transportation plan no new local 

violations will be created and the 

severity or number of existing violations 

will not be increased as a result of the 

project, and the project has been 

included in a regional emissions 

analysis that meets applicable §§ 93.118 

and/or 93.119 requirements. The 

demonstration must be performed 

according to the consultation 

requirements of § 93.105(c)(1)(i) and the 

methodology requirements of § 93.123. 

* * * * * 

§ 93.118 [Amended] 

■ 6. Section 93.118 is amended in 

paragraph (a) by removing the citation 

‘‘§ 93.109(c) through (l)’’ and adding in 

its place ‘‘§ 93.109(c) through (n)’’. 

■ 7. Section 93.119 is amended as 

follows: 

■ a. In paragraph (a), by removing the 

citation ‘‘§ 93.109(c) through (l)’’ and 

adding in its place ‘‘§ 93.109(c) through 

(n)’’; and 

■ b. By revising paragraph (e)(2). 

§ 93.119 Criteria and procedures: Interim 

emissions in areas without motor vehicle 

emissions budgets. 

* * * * * 

(e) * * * 

(2) The emissions predicted in the 

‘‘Action’’ scenario are not greater than: 

(i) 2002 emissions, in areas designated 

nonattainment for the 1997 PM2.5

NAAQS; or 

(ii) Emissions in the most recent year 

for which EPA’s Air Emissions 

Reporting Requirements (40 CFR Part 

51, Subpart A) requires submission of 

on-road mobile source emissions 

inventories, as of the effective date of 

nonattainment designations for any 

PM2.5 NAAQS other than the 1997 PM2.5

NAAQS. 

* * * * * 

§ 93.121 [Amended] 

■ 8. Section 93.121 is amended: 

■ a. In paragraph (b) introductory text 

by removing the citation ‘‘§ 93.109(l)’’ 

and adding in its place ‘‘§ 93.109(n)’’; 

■ b. In paragraph (c) introductory text 

by removing the citation ‘‘§ 93.109(j) or 

(k)’’ and adding in its place ‘‘§ 93.109(l) 

or (m)’’. 

[FR Doc. 2010–5703 Filed 3–23–10; 8:45 am] 

BILLING CODE 6560–50–P 


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