Interim Transportation Conformity
Guidance for 2006 PM,. NAAQS
^» -D
Nonattainment Areas
SERA
United States
Environmental Protection
Agency
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Interim Transportation Conformity
Guidance for 2006 PM,. NAAQS
^» -D
Nonattainment Areas
Transportation and Regional Programs Division
Office of Transportation and Air Quality
U.S. Environmental Protection Agency
SER&
United States
Environmental Protection
Agency
EPA-420-B-09-036
November 2009
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Table of Contents
Section 1. Introduction 2
1.1. Purpose of this Guidance 2
1.2. Background: Transportation Conformity 3
1.3. 2006 PM2.5 NAAQS and Designations 3
1.4. Relationship Between Transportation Conformity Requirements for the 2006
PM2.5 NAAQS and the 1997 PM2.5 NAAQS 4
1.5. Who can I contact for more information? 4
1.6. Does this guidance create any new requirements? 5
Section 2. General Requirements 6
2.1. Timing of First Transportation Plan and TIP Conformity Determination 6
2.2. General Requirements of a Conformity Determination for a Transportation Plan
and TIP for the 2006 PM2.5 NAAQS 7
2.3. Consultation for Transportation Plan/TIP Conformity Determinations 8
2.4. Timely Implementation of TCMs 9
2.5. Pollutants and Precursors Examined in the First Regional Emissions Analyses
for the 2006 PM2.5 NAAQS 10
2.6. What happens if an area misses the one-year conformity deadline? 12
Section 3. Regional Conformity Tests 13
3.1. Conformity Tests for the First Conformity Determination 13
3.2. Interim Emissions Tests 14
3.3. How should areas determining conformity for PM2 5 for the first time develop
a regional emissions analysis for an interim emissions test? 15
3.4. Can an area using an interim emissions test for 1997 PM2 5 conformity apply
the regional emissions analysis to 2006 PM2.s conformity as well? 16
3.5. Additional Guidance for 2006 PM2 5 Areas Using the Interim Emissions Tests.. 18
3.6. Baseline Year for the Baseline Year Test 18
3.7. Using 1997 PM2.5 NAAQS Budgets for 2006 PM2.5 Conformity 19
3.8. Multi-jurisdictional 2006 PM2.5 Areas That Have 1997 PM2.5 Budgets 20
Section 4. Project-level Conformity Requirements in 2006 PM2 5 Areas 23
4.1. Timing of Project-level Conformity Determinations for the 2006 PM2 5
NAAQS 23
4.2. General Requirements 23
4.3. What is a hot-spot analysis? 24
4.4. Which PM2.5 NAAQS has to be considered in a hot-spot analysis? 24
4.5. Where can I find more information about PM2 5 hot-spot analyses? 25
4.6. Compliance with PM2 5 SIP Control Measures 25
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Section 1. Introduction
1.1. Purpose of this Guidance
This document provides interim guidance for meeting transportation conformity
requirements in areas designated nonattainment for the 2006 24-hour PM2.5 national
ambient air quality standards ("2006 PM2.5 NAAQS"). EPA published a proposed "PM
Amendments" rule earlier this year1 to address the 2006 PM2.5 NAAQS, but the final rule
has not yet been published. Once the PM Amendments final rule is published, the
transportation conformity regulations will address the 2006 PM2.5 NAAQS.
In the interim, EPA is releasing this guidance to help new nonattainment areas meet
conformity requirements in time. Transportation conformity for the 2006 PM2 5 NAAQS
applies one year after the effective date of nonattainment designations for this NAAQS.
Clean Air Act 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 specific NAAQS.
EPA's final rule designating areas for the 2006 PM2.5 NAAQS is effective December 14,
2009. Given this effective date of designations, conformity for this NAAQS applies by
December 14, 2010. EPA will work with 2006 PM2.5 NAAQS nonattainment areas
("2006 PM2.5 areas" in this guidance) to help them meet requirements, and we
encourage consultation early.
This is interim guidance and will be replaced by the PM Amendments final rule.
However, conformity determinations done according to this guidance should be
consistent with the Clean Air Act and the existing transportation conformity rule, and the
PM Amendments proposed rule as described in this guidance. Conformity
determinations for the 2006 PM2 5 NAAQS completed under this interim guidance before
the PM Amendments final rule becomes effective will remain valid even after the
effective date of the PM Amendments final rule (i.e., the final rule would not trigger
another conformity determination for this NAAQS if one has already been completed).
This guidance document is consistent with what is currently required and being
implemented for PM2 5 conformity determinations in areas designated for the 1997 PM2 5
NAAQS.
The Federal Highway Administration (FHWA) and Federal Transit Administration
(FTA), EPA's federal partners in implementing the conformity rule, assisted in the
development of this guidance and concurred on its content.
1 The proposed rule entitled, "Transportation Conformity Rule PM25 and PM10 Amendments," ("PM
Amendments"), was published on May 15, 2009.
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1.2. Background: Transportation Conformity
Transportation conformity is required under Clean Air Act section 176(c) (42 U.S.C.
7506(c)) to ensure that federally funded or approved highway and transit 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 or contribute to new air quality violations, worsen existing violations, or delay
timely attainment or any interim milestones of the relevant NAAQS. EPA's
transportation conformity rule (40 CFR Parts 51 and 93) establishes the criteria and
procedures for determining whether metropolitan transportation plans, metropolitan
transportation improvement programs (TIPs), and federally supported highway and
transit projects conform to the SIP. Transportation conformity applies to designated
nonattainment and maintenance areas2 for transportation-related criteria pollutants:
ozone, PM2.5, PMio, carbon monoxide, and nitrogen dioxide.
1.3. 2006 PM25 NAAQS and Designations
EPA issued a final rule on October 17, 2006 that tightened the 24-hour PM2.5 NAAQS
from the 1997 level of 65 micrograms per cubic meter (|ig/m3) to 35 |ig/m3 (71 FR
61144). In this final rule, EPA retained the 1997 annual PM2.5 NAAQS of 15.0 |ig/m3.
This final rule was effective on December 18, 2006. 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/air/particlepollution/actions.html, under
the September 21, 2006 announcement.
EPA's final rule designating areas for the 2006 PM2 5 NAAQS, published in the Federal
Register on November 13, 2009, is effective December 14, 2009.
In this Federal Register notice, 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.3 That is, EPA's notice now
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.
2 "Maintenance areas" are those areas that were initially designated nonattainment for a criteria pollutant
and subsequently redesignated to attainment after 1990. Maintenance areas have SIPs developed under
Clean Air Act section 175A.
3 The 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.
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Transportation conformity applies for the NAAQS for which an area is designated
nonattainment.4 Therefore, in two of the 1997 PM2 5 areas, conformity applies for both
the 1997 annual and the 1997 24-hour NAAQS.5 In the other 37 1997 PM2.5 areas,
conformity applies for the 1997 annual NAAQS, and not the 1997 24-hour PM2 5
NAAQS.
For additional information about the nonattainment designations, refer to EPA's website
at: http://www.epa.gov/pmdesignations/2006standards/index.htm.
1.4. Relationship Between Transportation Conformity Requirements for the 2006
PM25 NAAQS and the 1997 PM25 NAAQS
Clean Air Act section 176(c)(5) requires conformity requirements to be met for the
applicable PM2 5 NAAQS in both 1997 and 2006 PM2 5 nonattainment and maintenance
areas. This is because nonattainment designations for the 1997 and 2006 PM2 5 NAAQS
are different designations with separate SIP requirements, different attainment dates, etc.
The October 2006 rule establishing the 2006 PM2.5 NAAQS did not revoke the 1997
annual or 24-hour PM2 5 NAAQS. EPA's nonattainment designations for the 2006 PM2 5
NAAQS do not affect existing 1997 PM2.5 NAAQS nonattainment designations. While
making conformity determinations for the 2006 PM2 5 NAAQS will entail additional
effort, it may be possible to rely on some of the work that has been done to address
conformity for the 1997 PM2.5 NAAQS, where areas are designated nonattainment for
both the 1997 and 2006 PM2.5 NAAQS. Refer specifically to Sections 3.4 and 4.4 of this
guidance for additional information on this point.
Sections 3 and 4 of this guidance provide information regarding conformity requirements
for regional emissions analyses and project-level analyses respectively for the 2006 PM2 5
NAAQS.
1.5. Who can I contact for more information ?
For questions concerning a particular 2006 PM2 5 nonattainment area, please contact the
transportation conformity staff person responsible for this area at the appropriate EPA
regional office. Contact information for EPA regional offices can be found on EPA's
website at: http://www.epa.gov/otaq/stateresources/transconf/contacts.htm
4 Clean Air Act section 176(c)(5) and 40 CFR 93.102(b).
5 These two 1997 PM2 5 areas, the Los Angeles-South Coast Air Basin, CA nonattainment area and the San
Joaquin Valley, CA nonattainment area have also been designated nonattainment for the 2006 PM2 5
NAAQS. While both the 1997 24-hour and 2006 24-hour PM2 5 NAAQS must be considered in these
areas, in practice if the more stringent 2006 24-hour PM2 5 NAAQS is met, then the 1997 24-hour PM2 5
NAAQS is met as well.
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General questions about this guidance can be directed to Laura Berry at EPA's Office of
Transportation and Air Quality, berry.laura@epa.gov, (734) 214-4858.
The May 15, 2009 PM Amendments proposed rule can be downloaded from EPA's
website at: http://www.epa.gov/otaq/stateresources/transconf/conf-regs.htm
Additional information regarding the transportation conformity rule and associated
guidance can be found on EPA's website at:
www.epa.gov/otaq/stateresources/transconf/index.htm
Additional information about the 2006 PM2.5 NAAQS nonattainment designations can be
found on EPA's website at:
http://www.epa.gov/pmdesignations/2006standards/index.htm
1.6. Does this guidance create any new requirements?
No, this guidance is based on Clean Air Act requirements and existing associated
regulations and does not create any new requirements. This guidance explains how to
implement current transportation conformity requirements in areas that have been
designated for the 2006 PM2.5 NAAQS, prior to EPA's PM Amendments final rule that
specifically addresses conformity for this NAAQS.
The Clean Air Act and EPA's regulations at 40 CFR Parts 51 and 93 contain legally
binding requirements. This document is not a substitute for those provisions or
regulations, nor is it a regulation itself. Thus, it does not impose legally binding
requirements on EPA, DOT, states, or the regulated community, and may not apply to a
particular situation based upon the circumstances. This guidance may be revised
periodically without public notice.
This guidance will be superseded by EPA's final rule for the PM Amendments.
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Section 2. General Requirements
2.1. Timing of First Transportation Plan and TIP Conformity Determination
Transportation conformity for the 2006 PM2 5 NAAQS does not apply until one year after
the effective date of nonattainment designations for this NAAQS.6 EPA's final rule
designating areas for the 2006 PM2 5 NAAQS is effective December 14, 2009, so
conformity for this NAAQS applies December 14, 2010.
The following discussion provides more details on the application of the one-year grace
period in newly designated nonattainment areas for the 2006 PM2 5 NAAQS in
metropolitan, donut and isolated rural areas. This information is consistent with how
conformity for new NAAQS has been implemented in the past.7 Also see Section III.B.
of the preamble of the PM Amendments proposed rule (74 FR 23026-23028).
A metropolitan planning organization (MPO) 8 and the U.S. Department of
Transportation (DOT) must make a conformity determination with regard to the 2006
PM2.5 NAAQS for the metropolitan transportation plan and TIP within one year after the
effective date of the initial nonattainment designation for this NAAQS. The MPO and
DOT can make such a conformity determination anytime during the one-year grace
period, as long as it is completed by December 14, 2010. However, if the MPO and DOT
miss the deadline, the nonattainment area would enter a conformity "lapse." See Section
2.8 below for more information on lapses.
Conformity determinations done by an MPO (or MPOs) must also include any donut
areas9 within the 2006 PM2.5 NAAQS area (40 CFR 93.102(b)(2) and 93.122(a)(l)).
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. 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). The
procedures for the interagency consultation process found in 40 CFR 93.105 or a state's
6 Clean Air Act 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.
7 For example, the one-year grace period for newly designated areas was discussed in the July 1, 2004 final
rule, 69 FR 40008 - 40009.
8 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. See
40 CFR 93.101 for the definition of metropolitan planning organization.
9 A donut area is defined in 40 CFR 93.101 as a geographic area outside a metropolitan planning area
boundary, but inside a designated nonattainment or maintenance area boundary that includes an MPO.
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approved conformity SIP must be used in making conformity determinations for
transportation plans and TIPs.
The interagency consultation group 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. 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).
In isolated rural areas,10 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, in an isolated rural area, a
conformity determination is required for the 2006 PM2.5 and other applicable NAAQS
only when a non-exempt FHWA/FTA project(s) needs funding or approval. Conformity
requirements for isolated rural areas can be found at 40 CFR 93.109(1).
See EPA's July 1, 2004 final rule for further background on how EPA has implemented
this conformity grace period for 1997 PM2.5 NAAQS areas (69 FR 40004).
2.2. Overview of Requirements of a Conformity Determination for a Transportation
Plan and TIP for the 2006 PM25 NAAQS
For all areas where conformity applies, including the 2006 PM2.5 areas, Table 1 found in
40 CFR 93.109(b) lists the conformity criteria that apply for transportation plans, TIPs,
and projects. See Section 4 of this guidance for information about conformity
determinations for federally funded or approved projects.
A transportation plan or TIP conformity determination must include a regional emissions
analysis that meets the requirements of 40 CFR 93.122. This regional emissions analysis
must:
use latest planning assumptions (40 CFR 93.110);
use the latest emissions model (40 CFR 93.111);11
10 Isolated rural nonattainment and maintenance areas are defined in 40 CFR 93.101 as areas that do not
contain or are not part of any metropolitan planning area as designated under the transportation planning
regulations. Refer to 40 CFR 93.101 for additional information.
11 The latest emissions model is currently MOBILE6.2 for all states except California, and EMFAC2007
for California. While EPA will soon be issuing the final MOVES model to replace MOBILE6.2 (a draft
version of MOVES has already been released and can be downloaded from EPA's website at
http://www.epa.gov/otaq/models/moves/index.htm), EPA will establish a grace period before MOVES is
required, according to 40 CFR93.111(b). Therefore, implementers will be able touseMOBILE6.2forthe
first 2006 PM2 5 NAAQS conformity determination if the regional emissions analysis is started before the
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pass the appropriate conformity test - the budget test and/or one of the interim
emissions tests - as described in Section 3 of this guidance.
In addition, other requirements must be met and documented in the transportation plan
and TIP conformity determination:
Interagency consultation and public participation (40 CFR 93.112) - see Section
2.3 of this guidance;
Timely implementation of transportation control measures (TCMs) in approved
SIPs (40 CFR 93.113) - see Section 2.4 of this guidance.
Please refer to the sections of the transportation conformity regulation noted above for
additional information that is not covered in this interim guidance.
2.3. Consultation for Transportation Plan/TIP Conformity Determinations
Interagency Consultation. Conformity must be determined in consultation with the
appropriate local, state, and federal agencies based on the requirements of 40 CFR
93. 1 12. If your state has an approved conformity SIP, consultation must meet the
requirements found in that SIP. 12 If your state does not have such an approved
conformity SIP, consultation must meet the requirements found in 40 CFR 93.105(a)(2).
When making a conformity determination, 2006 PM2.5 areas must use the interagency
consultation process to make decisions regarding specific aspects of the conformity
determination. For example, consultation must be used to:
Determine the model, methods, and assumptions to be used in regional emissions
analyses and hot-spot analyses13 (40 CFR 93.105(c)(l)(i)) - see footnote 1 1
regarding the emissions model to be used;
Determine whether there are any transportation projects in the area that don't fit
the definition of "regionally significant project" found in 40 CFR 93.101 but
should be included in the area's regional emissions analysis (40 CFR
end of the grace period for MOVES. See EPA's website at:
http://www.epa.gov/otaq/stateresources/transconf/policy.htm for upcoming MOVES SIP and conformity
policy guidance that will describe how MOVES will be applied in these areas.
12 A conformity SIP governs the conformity process in a state for the portions of the federal transportation
conformity regulations that it includes. A conformity SIP is required to contain only the state's criteria and
procedures for interagency consultation (40 CFR 93.105) and two additional conformity provisions (40
CFR 93 . 122(a)(4)(ii) and 93 . 125(c)). Unlike a reasonable further progress SIP, an attainment
demonstration, or maintenance plan, a conformity SIP does not contain motor vehicle emissions budgets,
emissions inventories, air quality demonstrations, or control measures. For more information, see EPA's
"Guidance for Developing Transportation Conformity State Implementation Plans (SIPs)," found on EPA's
website at: http://www.epa. gov/otaq/stateresources/transconf/policy/420b0900 1 .pdf .
13 This includes making specific decisions such as the time of year that should be modeled, as appropriate,
which years should be analyzed, and models and inputs to be used.
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Evaluate whether the area has any projects that are exempt according to 40 CFR
93.126 and 93.127 that should be treated as non-exempt (40 CFR
Determine whether there are any TCMs in an approved SIP for the area and
evaluate whether those TCMs are behind schedule. For any TCM behind
schedule, determine whether past obstacles to its implementation have been
identified and are being overcome, and whether the TCM is getting maximum
priority for approval and funding (40 CFR 93.105(c)(l)(iv)). See Section 2.4 of
this guidance for more information on this requirement.
Note that this is a partial list of items to be discussed through the interagency consultation
process; see the state's conformity SIP or the transportation conformity rule at 40 CFR
93. 105(c) for the complete list.
Those 2006 PM2.5 areas where conformity already applies for another NAAQS will be
able to use their existing interagency consultation process for making these decisions.
These areas should consider whether any additional agencies need to be part of the
process if the boundary of the 2006 PM2 5 area is different from the area where
conformity already applies.
Public Consultation. Agencies making conformity determinations must also give the
public an opportunity for comment, in accordance with the rule's requirements at 40 CFR
93. 105(e) or any state's approved conformity SIP. Note that the public must have access
to all technical and policy information considered by the agency making the conformity
determination at the beginning of the comment period, and prior to taking formal action
on the conformity determination. The requirements of a proactive public involvement
process are outlined in DOT's transportation planning regulations at 23 CFR 450.3 16(a).
2.4. Timely Implementation of TCMs
The conformity determination must include a demonstration of timely implementation of
TCMs in approved SIPs as required by 40 CFR 93.113(b) for transportation plans and 40
CFR 93.113(c) for TIPs. The conformity rule defines transportation control measures at
40 CFR 93.101. The requirements for timely implementation of TCMs apply only to
TCMs in an approved SIP. Most likely, 2006 PM2.s areas will not have an approved SIP
for this NAAQS during the time that this guidance is in effect.
However, these areas could have approved SIPs for the 1997 PM2.5 NAAQS or another
NAAQS. Conformity determinations for the 2006 PM2 5 NAAQS must ensure timely
implementation of any TCMs included in any approved SIPs for the area.14 EPA
addressed this point in the July 1, 2004 final rule:
14 If a TCM in an approved SIP has already been substituted with one or more other TCMs, the timely
implementation requirement applies to the substitute TCM(s). For additional information about
substituting TCMs, please refer to EPA's "Guidance for Implementing the Clean Air Act Section 176(c)(8)
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Clean Air Act section 176(c) requires that TCMs in approved SIPs be
implemented in a timely manner according to the schedules in the SIP.
This requirement is not contingent on what type of SIP, pollutant, or
standard for which the approved TCM was established. (69 FR 40013).
2.5. Pollutants and Precursors Examined in the First Regional Emissions Analyses
for the 2006 PMZ5 NAA QS
The transportation conformity rule at 40 CFR 93.102(b) describes the pollutants that must
be examined in a regional emissions analysis done for PM2 5:
Directly emitted PM^. In 2006 PM2.5 areas, regional conformity analyses must be
completed for directly emitted PM2.5 (40 CFR 93.102(b)(l)). Directly emitted PM2.5
includes exhaust, brake and tire wear emissions,15 and re-entrained road dust may also
have to be included as directly emitted PM2 5 as discussed below.
Oxides of nitrogen (NOx). Regional conformity analyses must be completed for NOx in
2006 PM2.5 areas, unless both the EPA Regional Administrator and the director of the
state air agency make a finding that transportation-related emissions of NOx within the
nonattainment area are not a significant contributor to the PM2 5 nonattainment problem
and notify the MPO and DOT (40 CFR 93.102(b)(2)(iv)).
Other potential precursors. Regional conformity analyses are not required for volatile
organic compounds (VOC), sulfur dioxide (SO2) or ammonia (NHa) in 2006 PM2 5 areas
unless either the EPA Regional Administrator or the director of the state air agency
makes a finding that transportation-related emissions of any of these precursors within
the nonattainment area are a significant contributor to the PM2 5 nonattainment problem
and notifies the MPO and DOT (40 CFR 93.102(b)(2)(v)).
Areas should use the interagency consultation process if there are questions about
whether conformity applies for a PM2 5 precursor.
Re-entrained road dust.
Re-entrained road dust emissions are produced by travel on paved and unpaved roads,
including emissions from anti-skid and de-icing materials. Re-entrained road dust isn't
included in the regional emissions analysis for direct PM2 5 unless either the EPA
Regional Administrator or the director of the state air agency makes a finding that re-
entrained road dust emissions within the area are a significant contributor to the PM2.5
nonattainment problem and notifies the MPO and DOT (40 CFR 93.102(b)(3)).
Transportation Control Measure Substitution and Addition Provision," found on EPA's website at:
http://www.epa.gov/otaq/stateresources/transconf/policy/420b09002.pdf.
15 The latest approved emissions model is used to estimate directly emitted PM2 5 from vehicle exhaust and
brake and tire wear - MOBILE6.2 in all states other than California, and EMFAC2007 in California.
10
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The interagency consultation process must be used to discuss what modeling methods
and data are appropriate for a conformity analysis, per 40 CFR 93.105(c)(l). Areas are
required to use AP-4216 to estimate road dust unless they have an EPA-approved local
method.
Construction dust.
Most areas will not need to be concerned about including construction-related fugitive
dust in a regional emissions analysis during the time that this interim guidance applies.
Construction-related fugitive dust needs to be included in a 2006 PM2.5 regional
emissions analysis only if the SIP identifies it as a significant contributor to the PM2 5
nonattainment problem, based on 40 CFR 93.122(f). In such a case, the regional PM2.5
emissions analysis has to consider construction-related fugitive PM2.5 and account for the
level of construction activity, the fugitive PM2.5 control measures in the SIP, and the dust-
producing capacity of the proposed activities (40 CFR 93.122(f)(2)).
The interagency consultation process must be used to discuss what methods and data are
appropriate for estimating construction dust emissions (40 CFR 93.105(c)(l)(i)). Either
AP-42 or locally-developed methods could be used, as determined through consultation.
16 See the Notice of Availability published May 19, 2004, (69 FR 28830-28832) found on EPA's website
at: http://www.epa.gov/fedrgstr/EPA-AIR/2004/Mav/Dav-19/all340.htm and more recently. EPA's
memorandum, "Policy Guidance on the Use of the November 1, 2006, Update to AP-42 for Re-entrained
Road Dust for SIP Development and Transportation Conformity," August 2, 2007, found on EPA's website
at: http://www.epa.gov/otaa/stateresources/transconf/policv/420b07055.pdf.
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The following table summarizes the information in Section 2.5:
Pollutants Examined for PM2.s Regional Emissions Analysis:
17
Pollutant/Precursor
Direct PM2.5 - exhaust, brake and tire wear
NOx
VOCs, SO2, or NH3
Re-entrained road dust
Construction dust
Included in 2006 PM2.5 Regional
Emissions Analysis?
Yes
Yes,
unless both EPA and the state find that it is
not a significant contributor
No,
unless either EPA or the state finds any of
these precursors are a significant
contributor (or SIP includes a budget for
any of these precursor)
No,
unless either EPA or the state finds it a
significant contributor (or included in SIP
budget)
No,
unless SIP identifies it as a significant
contributor
2.6. What happens if an area misses the one-year conformity deadline?
If, at the conclusion of the one-year grace period for newly designated areas, the MPO
and DOT have not made a transportation plan and TIP conformity determination for the
relevant pollutant and NAAQS, the area would be in a conformity "lapse." During a
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). The practical impact of a conformity lapse will vary on an area-by-area basis.
The lapse grace period found in 40 CFR 93.104(b)(3) and (c)(3) does not apply at the end
of the one-year conformity grace period for newly designated areas.
Although the one-year conformity grace period is available to isolated rural areas, most
likely no conformity consequences would occur. As discussed in Section 2.1 of this
guidance, a conformity determination is required in isolated rural areas only when a non-
exempt FHWA/FTA project needs funding or approval.
Section III.B. of the preamble of the PM Amendments proposed rule (74 FR 23026-
23028) also covers this information.
' Information in the table is based on 40 CFR 93.102(b)(2) and (3).
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Section 3. Regional Conformity Tests
The conformity rule provides several tests for determining whether transportation plans
and TIPs conform, and 40 CFR 93.109 indicates which test or tests are required in
specific circumstances. The budget test, described at 40 CFR 93.118, is used when an
area has either adequate or approved motor vehicle emissions budgets in a SIP. The
interim emissions tests are found at 40 CFR 93.119. When a 2006 PM2.5 area does not
have adequate or approved PM2.5 budgets for any PM2.5 NAAQS, one of the two interim
emissions tests must be done, as described below.
3.1. Conformity Tests for the First Conformity Determination
For the first conformity determination for the 2006 PM2 5 NAAQS, SIP budgets for this
NAAQS will not yet be submitted. Therefore, these areas will have to use a different test
for conformity:
If a 2006 PM2.5 area has adequate or approved SIP budgets from a SIP that
addresses the 1997 PM2.5 NAAQS, it must use the budget test for 2006 PM2.5
conformity18 (skip to Section 3.7);
If a 2006 PM2.5 area does not have adequate or approved budgets for the 1997
PM2.s NAAQS, it must use one of the interim emissions tests, either:
o the build-no-greater-than-no-build test ("build/no-build test") found at 40 CFR
93.119(e)(l), or
o the no-greater-than-baseline year emissions test ("baseline year test"),
described at 40 CFR 93.119(e)(2).
The information discussed here is consistent with the PM Amendments proposed rule;
see preamble Sections V and VI, and proposed regulatory text in §93.109(j) and (k) as
background.
The interagency consultation process must be used to determine which test for
conformity applies, and other details as described in Section 2.3 of this guidance.
Additional decisions will need to be made through interagency consultation if the area
covers multiple jurisdictions, for example, if the area includes portions of more than one
state, or is covered by more than one MPO.
18 At this time it is known that all but three areas that are designated for both the 2006 and 1997 PM2 5
NAAQS have 2006 PM2 5 nonattainment boundaries that cover exactly the same geographic area as the
1997 PM2 5 boundaries. In two areas the 2006 PM2 5 boundary is smaller than the 1997 PM2 5 boundary,
and one 2006 PM2 5 area is comprised of two 1997 PM25 areas. Therefore, in nearly all cases if 1997 PM25
budgets are available, meeting the budget test will be sufficient because it will cover the entire 2006 PM2 5
area. EPA will work with all areas to ensure they know which type of test applies for conformity.
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Where an area is also subject to conformity for the 1997 PM2.5 NAAQS, some of the
work done for the 1997 PM2 5 NAAQS conformity determination may be useful for the
2006 PM2.5 conformity determination. Refer to Section 3.4 of this guidance.
EPA will work DOT and state and local transportation and air quality agencies to
determine which conformity test applies in each 2006 PM2 5 area for the first
determination.
3.2. Interim Emissions Tests
As mentioned in Section 3.1. above, areas that do not have adequate or approved PM2 5
budgets for any PM2 5 NAAQS must use one of the interim emissions tests according to
the regulations at 40 CFR 93.119(e). As described in Section V of the PM Amendments
proposed rule preamble, the 2006 PM2.5 areas that must use one of the interim emissions
tests are either:
"Brand new" PM2.5 nonattainment areas, i.e., those that were designated
attainment for the 1997 PM2.5 NAAQS, or
Areas that were designated nonattainment for the 1997 PM2.5 NAAQS that do not
yet have adequate or approved budgets for the 1997 PM2 5 NAAQS.
These 2006 PM2 5 nonattainment areas have a choice between the following interim
emissions tests in 40 CFR 93.119 for conformity determinations conducted before
adequate or approved 2006 PM2 5 SIP budgets are established:
The build-no-greater-than-no-build test ("build/no-build test") found at 40 CFR
93.119(e)(l). In this test, conformity would be demonstrated if in each analysis
year, the transportation emissions reflecting the proposed transportation plan or
TIP (the "build" case) were less than or equal to emissions from the transportation
system that would result from current programs (the "baseline scenario" or "no-
build" case defined in 40 CFR 93.119(h)); OR
The no-greater-than-baseline year emissions test ("baseline year test"), described
at 40 CFR 93.119(e)(2). In this test, conformity would be demonstrated if in each
analysis year, the transportation emissions reflecting the proposed transportation
plan or TIP (the "build" case) were less than or equal to the level of motor vehicle
emissions in the baseline year. Refer to Section 3.6 of this guidance for a
discussion of baseline years.
These requirements are also discussed in Section V of the preamble of the PM
Amendments proposed rule.
Regardless of whether the area chooses the baseline year test or build/no-build test, the
required analysis years, based on 40 CFR 93.119(g), are:
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A year within five years of the date the analysis is being done;
The last year of the transportation plan / conformity determination; and
Intermediate years as necessary so that analysis years are not more than 10 years
apart.
Please refer to the transportation conformity rule for further explanation of these tests.
Note that those 2006 PM2.5 areas that contain more than one MPO and/or a donut portion
would follow EPA's existing 2004 guidance entitled, "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
Standards," (EPA420-B-04-012), (the "multi-jurisdictional guidance"). See Section 3.5
of this guidance for more information about the multi-jurisdictional guidance.
3.3. How should areas determining conformity for PM^s for the first time develop a
regional emissions analysis for an interim emissions test?
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(1).)
This 24-hour emissions inventory estimates direct PM2.5 and NOx emissions that result
from the build scenario using MOBILE6.2 in 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.19 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 Clean Air Act is met, for example by
choosing the season with the most frequent or most severe violations, or the season with
the highest VMT, or both.20 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).
Interagency consultation should be used to decide if more recent air quality data indicates
that a different season should be analyzed.
19 In California where EMFAC is used, areas should use the interagency consultation process to determine
appropriate methods.
20 Note 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 website at:
http://www.epa.gov/otaq/models/moves/index.htmand
http://www.epa.gov/otaq/stateresources/transconf/policv.htm for future MOVES guidance.
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For each analysis year, these emission factors from MOBILE6.2 for direct PM2.5 and
NOx 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.21
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 3.6. 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 addition information about conducting the build/no-build and
baseline year tests.
3.4. Can an area using an interim emissions test for 1997 PM2.s conformity apply
the regional emissions analysis to 2006 PM2.5 conformity as well?
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 a 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, if they meet applicable
requirements for both NAAQS (refer to Section 3.2 of this guidance and 40 CFR
93.119(g) for analysis year requirements).
In most 1997 PM2 5 areas, conformity applies only for the annual NAAQS.22 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
21 Specifically, 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 website 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
22 See Section 1.3 of this guidance. In two of the 1997 PM25 areas, conformity applies for both the 1997
annual PM25 NAAQS and the 1997 24-hour PM25 NAAQS. However, note that Section 3.4 of this
guidance would not apply to these two areas if they have adequate 1997 PM25 SIP budgets.
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NAAQS at the same time. This option applies only when using MOBILE6.2 for regional
emissions analyses.
23
Areas should develop the annual emissions for the 1997 PM2 5 NAAQS by estimating
emissions in two seasons, summer and winter; four seasons; or in the 12 months of the
year.24
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.s 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 seasonally-adjusted average daily VMT for the area of the analysis year.25
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
Clean Air Act is met, for example by choosing the season with the most frequent or most
severe violations, or the season with the highest VMT, or both.26 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 (see Section 3.6. for a
discussion of the baseline year in 2006 PM2 5 areas), or emissions in winter from the no-
build scenario.
Note that prior to the effective date of the PM Amendments final rule, the baseline year
for the 1997 and 2006 PM2.5 NAAQS will be the same year - 2002. After the effective
23 Areas in California should use the interagency consultation process to determine appropriate methods. In
all other 2006 PM25 areas, EPA expects that MOBILE6.2 will be used for the first 2006 PM2 5 conformity
determinations. Refer to footnote 11 for more information about the use of MOBILE6.2.
24 This interim guidance for 2006 PM2 5 areas does not change 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 forPM2.5 Nonattainment Areas for Use in SIPs and Conformity," EPA420-B-05-008, August
2005, found on EPA's website at:
http://www.epa.gov/otaq/stateresources/transconf/policv/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.
25 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 PM25 conformity.
26 Note 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's
MOVES guidance documents will differ from this interim guidance in this respect.
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date of the final rule, EPA has proposed in the PM Amendments proposed rule that the
baseline year for the 2006 PM2 5 NAAQS would be a different year. See Section 3.6 of
this guidance for additional discussion of the baseline year.
3.5. Additional Guidance for 2006 PM2.s Areas Using the Interim Emissions Tests
Any areas that use one of the interim emissions tests may also want to refer to Part 2 of
EPA's multi-jurisdictional guidance.27 Part 2 of the multi-jurisdictional guidance covers
conformity determinations and regional emissions analyses before SIP budgets are
adequate or approved, and specifically addresses the following topics:
The geographic area to be examined in a regional emissions analysis and
conformity determination before the area has adequate or approved budgets
(Question 3, p. 8 of multi-jurisdictional guidance);
How multi-jurisdictional areas can create a regional emissions analysis for the
entire nonattainment area (Question 4, p. 9 of multi-jurisdictional guidance);
The decisions to be made in the interagency consultation process (Question 5, p.
11 of the multi-jurisdictional guidance);
What occurs when one MPO can meet the requirements in 40 CFR 93.119 and the
other cannot (Question 6, p. 12 of the multi-jurisdictional guidance); and
Who has responsibility for estimating emissions in a donut area (Question 7, p. 13
of the multi-jurisdictional guidance).
3.6. Baseline Year for the Baseline Year Test
The required baseline year for the 2006 PM2.5 NAAQS may change once the PM
Amendments final rule is published and effective. Prior to the effective date of the final
rule, the baseline year for these areas is 2002 (found in 40 CFR 93.119(e)). However,
EPA has proposed to update the baseline year for 2006 PM2.5 areas, which if finalized,
would result in baseline years of either 2005 or 2008.
Any conformity determination finished28 before the PM Amendments final rule becomes
effective must use 2002 as the baseline year. Such a determination will remain valid
even after the effective date of the PM Amendments final rule, which may specify a
different baseline year for 2006 PM2.5 areas. Any conformity determination finished after
the effective date of the PM Amendments final rule must use the baseline year identified
in the final rule. (EPA proposed that only one of the options would be finalized, therefore
27 "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 Standards," EPA420-B-04-012, July 2004, found on EPA's website at
http://www.epa. gov/otaq/stateresources/transconf/policv/420b04012.pdf.
28 A conformity determination is finished on the date that DOT makes its conformity determination.
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only one of the two years identified above - either 2005 or 2008 - would be the resulting
baseline year).
EPA recommends that MPOs use the interagency consultation process to discuss the
likely timing of DOT's conformity determination, and which baseline year will most
likely be in effect at that time. EPA Regional Offices are available for consultation on a
case-by-case basis; refer to Section 1.5 for contact information.
MPOs using the baseline year test could also compare emissions from the future planned
transportation network to emissions in 2002, 2005, and 2008, since those are the baseline
years that would result from the options EPA set forth in the PM Amendments proposed
rule. However, EPA believes that the consultation process can help MPOs avoid this
additional work.
Note that the baseline year emissions need to be modeled rather than interpolated, based
on the latest emissions model and appropriate methods for estimating travel and speeds as
required by 40 CFR93.110, 93.111, and 93.122.
3.7. Using 1997 PM2 5 NAAQS Budgets for 2006 PM2.5 Conformity
As discussed in preamble Section IV of the PM Amendments proposed rule, where a
2006 PM2.5 area is covered by adequate or approved 1997 PM2.5 budgets, EPA believes
that the 1997 PM2 5 budgets must be used for 2006 PM2 5 conformity. Most of the areas
designated for both the 2006 and 1997 PM2.5 NAAQS have 2006 PM2.5 nonattainment
boundaries that cover exactly the same geographic area as the 1997 PM2.5 boundaries.
Therefore, in most cases if 1997 PM2.5 budgets are available, meeting the budget test will
be sufficient because it will cover the entire 2006 PM2 5 area.29 Consistent with the Clean
Air Act as interpreted by a court decision described below, these 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.
For areas that use 1997 annual PM2 5 budgets to meet 2006 PM2 5 requirements, a
regional emissions analysis for the 2006 PM2 5 NAAQS would necessarily be done based
on an analysis of annual emissions (tons per year), rather than 24-hour emissions (tons
per day).
This requirement to use adequate or approved 1997 PM2.5 budgets is based on EPA's
existing rule for areas designated for the 1997 8-hour ozone NAAQS that had SIP
budgets for the 1-hour ozone NAAQS and a 2006 court decision. EPA has proposed in
the PM Amendments proposed rule to add a regulatory provision to clarify this
requirement. Thus, EPA believes that using the existing 1997 PM2.5 budgets as a proxy
29 At this time, it is known that in two areas the 2006 PM2 5 boundary is smaller than the 1997 PM2 5
boundary, and that one 2006 PM2 5 area comprised of two 1997 PM2 5 areas. EPA will work with all areas
to ensure they know which type of test applies for conformity, particularly with the areas where the 2006
PM2 5 area boundary is not identical to the 1997 PM2 5 area boundary.
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for the 2006 PM2.5 NAAQS is required by the Clean Air Act. 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 in contrast to the provisions of EPA's rules under review,
where a motor vehicle emissions budget developed for the revoked 1-hour ozone
NAAQS existed in an approved SIP, the Act requires that 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. See Section VI of the preamble of the
PM Amendments proposed rule (74 FR 23032 - 23035), and the proposed regulatory text
in§93.109(k).
The 2006 PM2.5 areas with adequate or approved 1997 PM2.5 budgets can determine
conformity for both of these NAAQS at the same time. When using the budget test, the
regional emissions analysis must be performed for:
The attainment year for the applicable NAAQS, if it is in the timeframe of the
transportation plan and conformity determination;
The last year of the transportation plan/conformity determination; and
Intermediate years as necessary such that analysis years are no more than ten
years apart (40 CFR 93.118(d)).
Note that the analysis years chosen must meet 40 CFR 93.118(d) for each NAAQS. The
last year of the transportation plan will be the same regardless of NAAQS, but the
attainment years for the two NAAQS will be different. Based on Clean Air Act section
172(a)(2), the attainment year for the 2006 PM2.5 areas will be 2014, five years after the
effective date of designations, (December 13, 2009).30
For areas where 1997 PM2.5 subarea budgets are established, or where 1997 PM2.5
budgets are established for individual states in a multi-state area, the 2004 multi-
jurisdictional guidance addresses how conformity is done. See Section 3.8 for more
information. This information is also discussed in the PM Amendments proposed rule at
74 FR 23032-23035.
3.8. Multi-jurisdictional 2006 PM25 Areas That Have 1997 PM2.5 Budgets
In 2006 PM2.5 areas that include more than one MPO, an MPO and a donut area, or more
than one state, the multi-jurisdictional guidance referenced above provides relevant
guidance for preparing conformity determinations. The most relevant information from
the multi-jurisdictional guidance has been adapted and included here for 2006 PM2.5
30 Areas may be eligible for attainment date extensions, which is determined through the SIP process and
should not be relevant for the first conformity determination under the 2006 PM2 5 NAAQS. Please consult
the appropriate EPA Regional Office (see Section 1.5) for more information.
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areas, but please refer to the multi-jurisdictional guidance for further information
regarding how a regional emissions analysis could be completed for these areas.
More than one MPO. Where 1997 PM25 budgets cover more than one MPO, the
planning agencies will have to work together to develop one regional emissions analysis
for the entire 2006 PM2.5 area under 40 CFR 93.109(e)(2)(i), just as they have been doing
for the 1997 PM2.5 NAAQS. MPOs must coordinate their plan/IIP conformity
determinations and submit them to DOT. Once DOT receives all plan/TIP conformity
determinations for the 2006 PM2 5 area, DOT will make its conformity determinations at
the same time.
Subarea budgets. Where subarea budgets31 exist for the 1997 PM2.5 NAAQS, EPA
believes that these subarea budgets must also be used in the 2006 PM2.5 conformity
determination, because using the existing budgets will ensure that air quality progress to
date is maintained. In general, where a 2006 PM2 5 area has multiple MPOs with subarea
budgets for the 1997 PM2 5 NAAQS, EPA and DOT believe it is necessary for the first
conformity determination under the 2006 PM2 5 NAAQS to be conducted as follows:
each MPO would independently demonstrate conformity of its transportation plan and
TIP for the 2006 PM2.5 NAAQS using its 1997 PM2.5 subarea budgets. All of the MPOs'
plan/TIP conformity determinations would be submitted to DOT for DOT to make its
conformity determination. DOT will not make a conformity determination on any of the
plans or TIPs from the 2006 PM2 5 area until every MPO in the area has made a
conformity determinations for its plan and TIP. All MPOs in the 2006 PM2 5 area must
have an initial valid conformity determination for the 2006 PM2 5 NAAQS by the end of
the one-year grace period. If any do not, DOT will be unable to make a 2006 PM2.5
conformity determination for the 2006 PM2 5 area, and all of the MPOs' plans and TIPs
within that area would lapse.32
Multi-state areas. For multi-state 2006 PM2.5 nonattainment areas, the fact that existing
1997 PM2.s budgets must be used preserves states' ability to determine conformity
independently from one another, if a state has already established budgets for its own
state for the 1997 PM2.5 NAAQS. In other words, states can operate independently for
conformity to the 2006 PM2.5 NAAQS if they have adequate or approved 1997 PM2.5
budgets for their portion of the nonattainment area.
Specifically, conformity determinations for the 2006 PM2 5 NAAQS can be made in one
state of a multi-state 2006 PM2.5 area if it has adequate or approved 1997 PM2.5 budgets
31 Areas may have subarea budgets when there is more than one MPO in a nonattainment area (within one
state) per 40 CFR 93.124(d); in this case, each MPO must meet its own subarea budgets. See Part 3 of the
multi-jurisdictional guidance for more information.
32 In general, for subsequent conformity determinations, the MPOs can make conformity determinations
independently as long as all other MPOs in the area must have a conforming plan and TIP in place. If one
subarea is in a conformity lapse, conformity determinations for new or revised plans and TIPs cannot be
made in other subareas until the lapse ends.
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even if a lapse is occurring in another state in the 2006 PM2.5 area, or conformity had not
yet been determined for the 2006 PM2 5 NAAQS in another state in the area.
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Section 4. Project-level Conformity Requirements in 2006 PM2.s Areas
4.1. Timing of Project-level Conformity Determinations for the 2006 PM2.s NAAQS
The one-year grace period for conformity in newly designated areas described in Section
2.1 of this guidance also applies to project-level conformity determinations (including
hot-spot analyses in certain cases) in 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 before any new federal
approvals or authorizations for non-exempt FHWA and FTA projects can occur.
For non-exempt FHWA or FTA projects, a conformity determination is typically
completed as part of the National Environmental Policy Act (NEPA) process and prior to
issuance of a categorical exclusion, finding of no significant impact, or record of decision
under NEPA. If a non-exempt project still requires FHWA or FTA approval or
authorization after the last day of the one-year grace period, a project-level conformity
determination will be required for the 2006 PM2.5 NAAQS even if the project has already
completed the NEPA process, or for multi-phase projects, even if other phases of the
project have already been constructed. If no new FHWA or FTA approvals or
authorizations are required for a non-exempt project after the end of the one-year grace
period, then project-level conformity will not be required for the 2006 PM2 5 NAAQS.
Before the end of the one-year grace period, FHWA or FTA could choose to make a
project-level conformity determination that meets the conformity rule's requirements.
Please consult with the FHWA Division and FTA Regional Offices if you have questions
concerning how project-level conformity determinations are addressed in the NEPA
process.
This information is also found in the PM Amendments proposed rule preamble Section
m.B (74 FR 23026-8).
4.2. General Requirements
The existing conformity requirements that apply to PM2.5 areas (see Table 1 in 40 CFR
93.109) also apply to 2006 PM2.5 nonattainment or maintenance areas:
Project-level conformity determinations. All FHW A/FT A non-exempt projects
must have a project-level conformity determination (40 CFR 93.116(a));
Hot-spot analyses. A PM2 5 hot-spot analysis is required only for certain kinds of
projects (listed at 40 CFR 93.123(b)(l)); in all other cases, a hot-spot analysis is
not required (according to 40 CFR 93.116(a)).
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Interagency consultation. The procedures for interagency consultation found in a
state's approved conformity SIP or 40 CFR 93. 105 must be used in making
project-level conformity determinations. See specifically 40 CFR 93.105(c)(l)(i),
and refer to Section 2.3 of this guidance for additional information about
interagency consultation.
Compliance with PM^ SIP control measures in approved SIPs, if any. See
Section 4.6 below.
4.3. What is a hot-spot analysis?
A hot-spot analysis is defined in 40 CFR 93.101 as an estimation of likely future
localized PM2 5 pollutant concentrations and a comparison of those concentrations to the
NAAQS. A hot-spot analysis assesses the air quality impacts on a scale smaller than an
entire nonattainment area, including for example, congested roadway intersections and
highways or transit terminals. Such an analysis is a means of demonstrating that a
transportation project meets Clean Air Act conformity requirements to support state and
local air quality goals with respect to potential localized air quality impacts.
Note that in the PM Amendments proposed rule, EPA has proposed minor wording
changes to the hot-spot rules at 40 CFR 93.116(a). These proposed changes, if finalized,
would not affect the substantive requirements in EPA's current hot-spot regulations. See
Section IX of the preamble of the May 2009 PM Amendments proposal (74 FR 23037-
40) and proposed regulatory text in §93.116(a).
4.4. Which PM2.5NAAQS has to be considered in a hot-spot analysis?
A hot-spot analysis must consider any PM2.s NAAQS for which an area has been
designated nonattainment. A hot-spot analysis 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, e.g.:
if an area is designated nonattainment for only the 2006 24-hour NAAQS, the
analysis would have to consider only that 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 24-hour
NAAQS, as well as the 2006 24-hour NAAQS, the analysis would have to
consider all of these NAAQS.33
33 While both 24-hour NAAQS must be considered, in practice if the more stringent 2006 24-hour PM2s
NAAQS is met, then the 1997 24-hour PM2 5 NAAQS is met as well.
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EPA and DOT 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. If you need assistance regarding a hot-
spot analysis, see Section 1.5 of this guidance for contact information for EPA regional
offices, and the following websites for FHWA division and FTA regional offices,
respectively:
http://www.fhwa. dot.gov/field.html
http://www.fta.dot.gov/regional offices.html
4.5. Where can I find more information about PM2.s hot-spot analyses ?
Please refer to the March 10, 2006 final rule for additional information regarding PM hot-
spot analyses (71 FR 12468) and EPA and FHWA's current guidance for implementing
this requirement, entitled, "Transportation Conformity Guidance for Qualitative Hot-spot
Analyses in PM2 5 and PMi0 Nonattainment and Maintenance Areas," March 2006,
(EPA420-B-06-902). This guidance can be found on EPA's website at:
http://www.epa.gov/otaq/stateresources/transconf/policy/420b06902.pdf
The qualitative hot-spot guidance answers questions such as:
What projects need a PM2.5 hot-spot analysis?
What methods can be used for performing qualitative PM2.5 hot-spot analyses?
What should be documented for a qualitative PM2.5 hot-spot analysis?
What emissions are considered in a PM2.5 conformity analysis for a project?
What time frame and analysis years should be used in hot-spot analyses?
Note that the qualitative guidance is to be used for hot-spot analyses until the requirement
for quantitative analysis takes effect. During the time that this interim guidance is in
effect, PM2.5 hot-spot analyses will be done qualitatively.34
4.6. Compliance with PM2.s SIP Control Measures
In PM2.5 areas, the conformity rule at 40 CFR 93.117 requires that before FHWA and
FTA projects can be determined to be in conformity, written commitments from the
project sponsor or operator to implement any PM2.5 project-level mitigation or control
measures in an approved SIP must be obtained. See EPA's July 2004 final rule for
further information on this requirement (69 FR 40036-40037).
The requirements for quantitative analysis will take effect when EPA releases modeling guidance on this
subject and announces it in the Federal Register, based on the regulation at 40 CFR 93.123(b)(4). EPA
will establish a grace period before quantitative analysis is required. See EPA's website at:
http://www.epa.gov/otaq/stateresources/transconf/policy.htm for upcoming MOVES SIP and conformity
policy guidance, including upcoming quantitative hot-spot modeling guidance.
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