Transportation Conformity Guidance for
2012 PM9 Nonattainment Areas
^» j
&EPA
United States
Environmental Protection
Agency
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Transportation Conformity Guidance for
2012 PM., Nonattainment Areas
Transportation and Climate Division
Office of Transportation and Air Quality
U.S. Environmental Protection Agency
&EPA
United States
Environmental Protection
Agency
EPA-420-B-15-091
November 2015
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Table of Contents
Table of Contents 1
Section 1. Background 2
1.1 What is the purpose of this guidance? 2
1.2 What is transportation conformity? 3
1.3 Who can I contact for more information? 4
1.4 Does this guidance create any new requirements? 4
Section 2. Implementation of the 2012 PM2.5 NAAQS and Revocation of the 1997 PM2.5
NAAQS 5
2.1 When will conformity apply for the 2012 PM2.s NAAQS? 5
2.2 Will EPA revoke the 1997 PM2.5 NAAQS? 5
2.3 How will retention of the 1997 annual PM2.s NAAQS as a secondary NAAQS
be addressed? 6
2.4 Making initial 2012 PM2.s conformity determinations 6
2.5 What happens if a 2012 PM2.s NAAQS nonattainment area with an MPO
misses the one-year conformity deadline? 7
Section 3. Completing Conformity Determinations for the 2012 PM2.s NAAQS 8
3.1 Overview of requirements of a conformity determination for a transportation
plan and TIP for the 2012 PM2.5 NAAQS 8
3.2 For which direct PM2.s pollutants and PM2.s precursors must conformity be
determined in areas designated nonattainment for the 2012 PM2.s NAAQS? .... 9
3.4 Using budgets from a previous PM2.sNAAQS for 2012 PM2.s conformity 10
3.5 Multi-jurisdictional 2012 PM2.s NAAQS areas that have budgets for a previous
PM2.5NAAQS 11
3.6 Using an interim emissions test to determine 2012 PM2.s conformity 12
3.7 Baseline year for the baseline year test 12
3.8 Analysis years for 2012 PM2.s conformity 12
3.9 Examples for 2012 PM2.s conformity determinations 14
3.10 Relying on a previous PM2.s regional emissions analysis when making a
conformity determination for the 2012 PM2.s NAAQS 15
Section 4. Emissions Models to Be Used When Implementing the 2012 PM2.s NAAQS 16
4.1 What emissions model do I use when completing 2012 PM2.s NAAQS
conformity determinations? 16
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Section 1. Background
1.1 What is the purpose of this guidance?
This document provides guidance for meeting transportation conformity requirements in
areas designated nonattainment for the 2012 primary annual PIVb.s national ambient air
quality standards ("2012 PM2.5NAAQS"). The 2012 PM2.5NAAQS was established at
12.0 micrograms per cubic meter (ug/m3). The designated nonattainment areas are as
follows:
State
CA
OH
PA
4 states
Area Name
Imperial County, CA
San Joaquin Valley Air Basin, CA
Los Angeles-South Coast Air Basin, CA
Plumas County, CA
West Silver Valley, ID
Cleveland, OH
Delaware County, PA
Lebanon County, PA
Allegheny, PA
9 areas
EPA Designated Nonattainment Counties
Imperial, CA (p)
Fresno, CA
Kern, CA (p)
Kings, CA
Madera, CA
Merced, CA
San Joaquin, CA
Stanislaus, CA
Tulare, CA
Los Angeles, CA (p)
Orange, CA
Riverside, CA (p)
San Bernardino, CA (p)
Plumas, CA (p)
Shoshone, ID (p)
Cuyahoga, OH
Lorain, OH
Delaware, PA
Lebanon, PA
Allegheny, PA
13 full counties, 7 partial counties
(p) - partial counties
EPA's final rule designating nonattainment areas for the 2012 PM2.5 NAAQS was
published in the Federal Register (see 80 FR 2206) on January 15, 2015 and is effective
April 15, 2015. Additional information regarding the designations can be found on EPA's
Greenbook website and 2012 PIVh.s Initial Designations webpage.l This rule established
initial air quality designations and classifications for the 2012 PM2.5 NAAQS for most
areas in the United States.2
Clean Air Act (CAA) section 176(c)(6) and the conformity regulation at 40 CFR
93.102(d) provide a one-year grace period from the effective date of designations before
1 http://www3.epa.gov/airqualitv/greenbk/kindex.html and
http://www.epa.gov/airqualitv/particlepollution/designations/2012standards/state.htm.
2 This final rule also classified all nonattainment areas for the 2012 annual PM2 5 NAAQS as Moderate
nonattainment areas as required by Clean Air Act section 188(a).
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transportation conformity applies in areas newly designated nonattainment for a specific
NAAQS. Transportation conformity for the 2012 PM2.5 NAAQS applies one year after
the effective date of nonattainment designations for this NAAQS (i.e., April 15, 2016).
EPA will work with 2012 PM2.5 NAAQS nonattainment areas to help them meet
conformity requirements as they implement this NAAQS. We encourage early
consultation to ensure any questions or issues are addressed in a timely manner. EPA
contact information is provided in Section 1.3.
Today's guidance is intended to take the information contained in the transportation
conformity rule (40 CFR Part 93) and EPA's existing guidance for implementing
conformity in multi-jurisdictional areas, and demonstrate how conformity specifically
applies in the context of the 2012 PIVh.s NAAQS. The transportation conformity rule is
already structured so that existing conformity requirements will apply for any new or
revised NAAQS; the conformity rule, therefore, applies directly and does not need to be
updated to reflect the 2012 PM2.5 NAAQS.3 In addition, EPA's "Guidance for
Transportation Conformity Implementation in Multi-jurisdictional Nonattainment and
Maintenance Areas," (EPA420-B-12-046, July 2012, referred to as the "Multi-
jurisdictional Guidance") is also applicable to any NAAQS for which conformity applies,
including the 2012 PM2.5 NAAQS.4 The Multi-jurisdictional Guidance describes how
conformity determinations are made on metropolitan transportation plans and
transportation improvement programs (TIPs) when a nonattainment or maintenance area
involves more than one Metropolitan Planning Organization (MPO5), more than one
state, or both, and describes what conformity tests apply. Today's guidance should help
agencies implementing the 2012 PM2.5 NAAQS and address the situations specific to this
NAAQS most likely to be encountered. The Multi-jurisdictional Guidance and this PM2.5
guidance are consistent with each other as both are based on the conformity regulations.
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.
1.2 What is transportation conformity?
Transportation conformity is required under CAA 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).
3 EPA's March 14, 2012 final rule (77 FR 14979; also known as the "Conformity Restructuring Rule")
restructured the transportation conformity rule so that existing conformity requirements will apply for any
new or revised NAAQS. This was done to reduce the need to amend the rule in the future merely to
reference a specific NAAQS and to provide more certainty to transportation planners as conformity
provisions could apply generally to any newly designated NAAQS. Therefore, the transportation
conformity rule does not need to be updated specifically to include implementation of the 2012 PM2 5
NAAQS. This guidance refers to the appropriate sections of the current conformity rule.
4 The Multi-jurisdictional Guidance can be found on EPA's website
at:www.epa.gov/otaq/stateresources/transconf/policy.htm.
5 See 40 CFR 93.101 for the definition of MPO.
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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 of the relevant NAAQS or any interim milestones. EPA's transportation
conformity rule (40 CFR Parts 51 and 93) establishes the criteria and procedures for
determining whether metropolitan transportation plans, TIPs, and federally supported
highway and transit projects conform to the SIP. Transportation conformity applies to
designated nonattainment and maintenance areas6 for transportation-related criteria
pollutants: ozone, PM2.5, PMio, carbon monoxide, and nitrogen dioxide.
1.3 Who can I contact for more information ?
For questions concerning a particular 2012 PIVh.s NAAQS 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: www.epa.gov/otaq/stateresources/transconf/contacts.htm.
General questions about this guidance can be directed to EPA's Office of Transportation
and Air Quality: Astrid Terry, terry.astrid@epa.gov , (734) 214-4812 or Rudy Kapichak,
kapichak.rudy@epa.gov, (734) 214-4574.
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 2012 PM2.5 nonattainment designations can be found at
Area Designations for the 2012 Annual Fine Particle (PIVb.s) Standard webpage.
1.4 Does this guidance create any new requirements?
No, this guidance is based on CAA 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 nonattainment
for the 2012 PM2.5 NAAQS.
The CAA 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, the
U.S. Department of Transportation (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.
6 "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
CAA section 175A.
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Section 2. Implementation of the 2012 PIVh.s NAAQS and Revocation of
the 1997 PM2.5NAAQS
2.1 When will conformity apply for the 2012 PM25NAAQS?
As noted in Section 1.1, CAA section 176(c)(6) and 40 CFR 93.102(d) provide a one-
year grace period from the effective date of PM2.5 designations before transportation
conformity applies in areas newly designated nonattainment for a specific NAAQS.
Therefore, transportation conformity for the 2012 PIVh.s NAAQS does not apply until one
year after the effective date of nonattainment designations for this NAAQS. As EPA's
final rule designating areas for the 2012 PIVh.s NAAQS was effective April 15, 2015,
conformity for this NAAQS applies beginning on April 15, 2016.7
Section 2.4 provides further details for how the one-year grace period applies in newly
designated nonattainment areas for the 2012 PM2.5 NAAQS in both metropolitan areas
(areas with an MPO) and isolated rural areas.
2.2 Will EPA revoke the 1997 PM2 5 NAAQS?
When EPA completed its review of the suite of PM NAAQS in December 2012, EPA
established a new primary annual NAAQS of 12.0 ug/m3 to protect public health. EPA
also retained the 1997 secondary annual NAAQS of 15.0 ug/m3 to protect against certain
welfare effects.8 EPA did not take any action to revoke the 1997 primary annual PIVh.s
NAAQS in the December 2012 PIVh.s NAAQS rulemaking. Additionally, EPA did not
revise either the 1997 24-hour PM2.5 NAAQS of 65 ug/m3 or the 2006 24-hour PM2.5
NAAQS of 35 ug/m3 in that rulemaking. Those PIVh.s NAAQS remain in place and
transportation conformity requirements continue to apply.
In March 2015, EPA proposed an implementation rule for the 2012 PM2.5 NAAQS that
included proposed options for revoking the 1997 primary annual PM2.5 NAAQS.9 At this
time EPA has not yet finalized that proposal. Nonattainment and maintenance areas for
the 1997 annual PM2.5 NAAQS should check with their EPA Regional Office for updates
on the finalization of that rule. After the PM implementation rule is finalized, EPA will
provide additional transportation conformity-related guidance on the transportation
conformity webpage
http://www3.epa.gov/otaq/stateresources/transconf/policy.htmtfcontent.
Areas should be aware that none of these actions affect designations or transportation
conformity requirements for the 1997 24-hour PM2.5 NAAQS or the 2006 24-hour PM2.5
NAAQS.
7 See http://www3.epa.gov/airqualitv/greenbk/kindex.html for all related FR notices and latest area
designations status.
8 See 78 FR 3086, January 15, 2013.
9 See 80 FR15340, March 23, 2015.
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2.3 How will retention of the 1997 annual PM2.s NAAQS as a secondary NAAQS be
addressed?
As discussed above in Section 2.2, EPA retained the 1997 annual PM2.5 NAAQS as a
secondary NAAQS as part of our review of the PM NAAQS in December 2012. In the
near term, this does not result in any changes in transportation conformity requirements
for nonattainment and maintenance areas for the 1997 annual PIVh.s NAAQS since the
1997 primary and secondary annual NAAQS are identical and transportation conformity
applies to both primary and secondary NAAQS.10
As discussed in Section 2.2 above, in March 2015, EPA proposed an implementation rule
for the PM2.5 NAAQS, and discussed the retention of the secondary NAAQS (include
specific FR cite). After the PM implementation rule is finalized, EPA will provide
additional transportation conformity-related guidance on the transportation conformity
web page, http://www.epa.gov/otaq/stateresources/transconf/policy.htm.
2.4 Making initial 2012 PM2.s conformity determinations
Nonattainment Areas with One or More MPO
An MPO and DOT must make a conformity determination with regard to the 2012 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 the determination is completed by April 15, 2016. However, if the
MPO and/or DOT miss the deadline, the nonattainment area would enter a conformity
"lapse." See Section 2.5 for more information on lapses.
MPOs must continue to meet conformity requirements for any other applicable NAAQS,
including any other applicable PM2.5 NAAQS. 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 transportation plan and/or TIP is adopted). The procedures
for the interagency consultation process found in 40 CFR 93.105 or a state's approved
conformity SIP must be used in making conformity determinations for transportation
plans and TIPs. See Section 3 for more information on interagency consultation.
Conformity determinations done by an MPO (or MPOs) must also include any donut
areas11 within the 2012 PM2.5 NAAQS area (40 CFR 93.122(a)(l)). Each newly
designated nonattainment area that includes a donut portion must use the interagency
process to determine how best to include donut area emissions in the MPO's regional
emissions analysis and transportation plan and TIP conformity determination (40 CFR
93.105(c)(3) or the state's conformity SIP). For more discussion on how conformity
10 CAA section 176(c)(6).
11 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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determinations should be made for donut areas, see the preamble to the July 1, 2004
conformity rule (69 FR 40013) and EPA's Multi-jurisdictional Guidance.
Isolated Rural Nonattainment and Maintenance Areas
In isolated rural areas,12 as in other newly designated nonattainment areas, the one-year
conformity grace period for the 2012 PIVh.s NAAQS began on the effective date of an
isolated rural area's initial nonattainment designation, April 15, 2015. 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)). Therefore, such areas are
not required to complete a conformity determination by the end of the one-year grace
period. Instead, in an isolated rural area, a conformity determination is required for the
2012 PM2.5 and other applicable NAAQS only when a non-exempt FHWA/FTA
project(s) needs funding or approval, based on the conformity requirements for isolated
rural areas at 40 CFR 93.109(g).
2.5 What happens if a 2012 PMi.s NAAQS nonattainment area with an MPO
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
2012 PM2.5 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
(i.e., exempt projects, project phases that were approved before the lapse, and
transportation control measures (TCMs) in approved SIPs). 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 for newly designated nonattainment areas at
the end of the one-year conformity grace period.13
12 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.
13 See 73 FR 4423-4424 (January 24, 2008) and the Multi-jurisdictional Guidance for additional details
about the lapse grace period.
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Section 3. Completing Conformity Determinations for the 2012 PIVh.s
NAAQS
The conformity rule provides several tests for determining whether transportation plans,
TIPs, and projects not from a conforming plan or TIP conform, and describes which test
or tests are required in specific circumstances (40 CFR 93.109). The budget test (40 CFR
93.118) is used when an area has either adequate or approved budgets for a pollutant in a
SIP. Therefore, when a 2012 PIVh.s NAAQS area has adequate or approved budgets for
any PIVh.s NAAQS, the budget test requirements in 40 CFR 93.118 must be met. When a
2012 PM2.5 NAAQS area does not have adequate or approved budgets for any PIVb.s
NAAQS, an interim emissions test must be used (40 CFR 93.119). There are also some
cases, prior to 2012 PM2.5 SIP budgets being available, where both the budget test and an
interim emissions test are required. How these tests are applied is described in more
detail in this section.
Note that, once 2012 PIVh.s SIP budgets are found adequate or approved, areas must use
the budget test with those budgets to determine 2012 PIVh.s conformity (40 CFR
93.109(c)(l)). This section focuses on how 2012 PIVh.s areas determine conformity
before such 2012 PM2.5budgets are available (40 CFR 93.109(c)(2) and (3)).
3.1 Overview of requirements of a conformity determination for a transportation
plan and TIP for the 2012 PM25NAAQS
For all areas where transportation conformity applies, including the 2012 PIVh.s NAAQS
areas, Table 1 found in 40 CFR 93.109(b) lists the conformity criteria that apply for
transportation plans, TIPs, and projects in 40 CFR 93.110 through 93.119.
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);14
• Pass the appropriate conformity test - the budget test and/or the interim emissions
test (40 CFR 93.118 and 93.119).
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);
• Timely implementation of TCMs in approved SIPs (40 CFR 93.113).
Please refer to the sections of the transportation conformity regulation noted above for
additional information that is not covered in this guidance.
14 See Section 4 for more information about which emissions model should be used for regional conformity
analyses for the 2012 PM25 NAAQS.
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3.2 For which direct PM2.spollutants and PM2.5precursors must conformity be
determined in areas designated nonattainment for the 2012 PM2.5 NAAQS?
If the newly designated 2012 PIVh.s nonattainment area doesn't have any PIVh.s SIP
budgets, the area should complete its regional conformity analysis for PIVh.s and NOx
emissions. If the area does have budgets for another PM2.5 NAAQS, the area should
complete conformity for the PIVb.s pollutants addressed by the adequate or approved
budgets.
3.3 Conformity tests for the first conformity determination for the 2012 PM2.s
NAAQS
It is not expected that SIP budgets for the 2012 PIVb.s NAAQS will be available in time
for the first conformity determination. Most if not all 2012 PIVh.s areas will have to rely
on the conformity tests in 40 CFR 93.109(c)(2) and (3).
Are budgets available?
If 1997 or 2006 PM2.5 NAAQS budgets
are available, for each analysis year in a
conformity determination for the 2012
PM2.5 NAAQS
If no PM2.5 budgets are available at all, for
each analysis year in a conformity
determination for the 2012
Use these budgets/tests
Use 1997 or 2006 PM2.5 budgets that are
established for that year or the most recent
prior year (see Sections 3.4 and 3.5).
Use an interim emissions test, (see
Sections 3.6 through 3.7)
When using the budget test, consistency with budgets must be demonstrated for each year
for which there are adequate or approved PIVb.s SIP budget(s) (40 CFR 93.118(b)) and for
analysis years (40 CFR 93.118(d)(2)). In each of these years, emissions must be less than
or equal to the budget(s) established for that year (40 CFR 93.118(b)(l)(i)); when no
budget(s) have been established for that year, then emissions must be less than or equal to
budget(s) established for the most recent prior year (40 CFR 93.118(b)(l)(ii)). A budget
cannot be used for an analysis year if it is established for a year later than the analysis
year.
In addition, the interagency consultation process described in 40 CFR 93.105 must be
used to determine how conformity applies in a specific area. Additional decisions will
need to be made through interagency consultation if the area covers multiple
jurisdictions, for example, if the area is covered by more than one MPO.
EPA will work with DOT and state and local transportation and air quality agencies to
determine which conformity test(s) applies in each 2012 PM2.5 NAAQS area for the first
determination. See Section 1.3 for EPA contact information.
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3.4 Using budgets from a previous PM2.sNAA QSfor 2012 PM2.s conformity
In general, if an area does not have adequate or approved SIP budgets for the 2012
NAAQS, but has budgets for the previous 1997 or 2006 PM2.5 NAAQS, these budgets
must be used in the budget test. Where such budgets do not cover the entire area, the
interim emissions test may also have to be used (40 CFR 93.109(c)(2)(iii) and (iv)).
A 2006 court decision established the legal parameters for using existing budgets as the
regional conformity test (EnvironmentalDefense v. EPA, 467 F.3d 1329 (DC Cir. 2006)).
EPA incorporated the court's decision for ozone conformity tests in its January 24, 2008
final rule (73 FR 4424). While the court's decision concerned the 1997 ozone NAAQS,
EPA believes the court's holding is relevant for other pollutants and NAAQS for which
conformity must be demonstrated. Therefore, EPA incorporated the court's decision
regarding conformity tests in its March 24, 2010 final rule (the "PM Amendments" rule,
75 FR 14260). In its "Conformity Restructuring Rule" (77 FR 14979), EPA reorganized
40 CFR 93.109(c) so that the court's decision is incorporated in the regulation for all
NAAQS for which conformity applies.
As described in the Conformity Restructuring Rule, there are four generic scenarios for
how an area's boundaries for the relevant NAAQS relate to boundaries covered by
budgets for another NAAQS of the same pollutant. For purposes of the 2012 PM2.5
NAAQS areas that have budgets from a previous PM2.5 NAAQS, the relevant scenarios
are:
• Scenario 1: Boundaries for both the 2012 PM2.5 NAAQS and previous PM2.5
NAAQS areas are identical.
• Scenario 2: Boundary of the 2012 PIVh.s area is smaller than and completely
within the area designated for the previous PM2.5 NAAQS.
Some areas designated nonattainment for the 2012 PM2.5 NAAQS will be "Scenario 1"
areas (that is, will have identical boundaries for both the 2012 PIVh.s NAAQS and a
previous PM2.5 NAAQS). Consistent with the CAA as interpreted in the court decision
described above, these areas must demonstrate conformity by meeting the budget test for
the 2012 PM2.5 NAAQS using existing adequate or approved SIP budgets for the
previous PM2.5 NAAQS until adequate or approved budgets for the 2012 PIVh.s NAAQS
are effective (40 CFR 93.109(c)(2)(i)).
There are also a few "Scenario 2" areas, where areas have budgets for a previous PIVh.s
NAAQS that cover an area larger than that designated for the 2012 PIVh.s NAAQS. In
these cases, the interagency consultation process should be used to determine how to
apply the budget test in those areas (40 CFR 93.109(c)(2)(ii)). The regulations further
describe using interagency consultation to determine budgets for other NAAQS where
such portion(s) can reasonably be identified. 40 CFR 93.109(c)(2)(ii)(B) describes if
additional emissions reductions are necessary to meet the budget test, the emissions
reductions must come from within such nonattainment area.
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For all areas, given that there are several factors to consider, such as what previous
NAAQS budgets are available, the geographic area they cover, and the years in which
they are established, the interagency consultation process should be used to determine
what test or tests will be used for an analysis year and how it should be applied to the
area. In addition, Section 3.9 gives some examples of how the various tests might be
applied in certain 2012 PIVh.s NAAQS situations.
3.5 Multi-jurisdictional 2012 PM2.5 NAAQS areas that have budgets for a previous
PM25NAAQS
For 2012 PM2.5 areas that have budgets for a previous PM2.5 NAAQS but also include
more than one MPO, an MPO and a donut area, and/or more than one state, Section 4 of
the Multi-jurisdictional Guidance provides detailed guidance for preparing conformity
determinations. The most relevant information from the Multi-jurisdictional Guidance
has been adapted and included here for the 2012 PM2.5 NAAQS, but please refer to the
Multi-jurisdictional Guidance for further information regarding how a regional emissions
analysis could be completed for these areas.
Subarea budgets. Where subarea budgets15 exist for a previous PM2.5 NAAQS, these
subarea budgets must also be used in the 2012 PM2.5 conformity determinations (40 CFR
93.109(c)(2) and 93.124(d)). Using the existing budgets will ensure that air quality
progress to date is maintained. In general, EPA and DOT believe it is necessary for the
first conformity determination in such areas under the 2012 PM2.5 NAAQS to be
performed as follows:
• Each MPO would demonstrate conformity of its transportation plan and TIP to the
2012 PM2.5 NAAQS using the subarea budgets for the previous PM2.5 NAAQS.
• All of the MPOs' transportation plan/TIP conformity determinations would then
be submitted to DOT.
• DOT will not make its conformity determination on any of the transportation
plans or TIPs for the 2012 PM2.5 NAAQS until every MPO in the area has made a
conformity determination for its transportation plan and TIP.
All MPOs within the area must have a conformity determination for the 2012 PM2.5
NAAQS by the end of the one-year grace period under 40 CFR 93.102(d). If any do not,
DOT will be unable to make any conformity determinations for the MPOs within the
2012 PM2.5 area, and all of the MPOs' transportation plans and TIPs will lapse.16
15 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 4 of the
Multi-jurisdictional Guidance for more information.
16 In general, for subsequent conformity determinations, the individual MPOs can make conformity
determinations independently as long as all other MPOs in the area have a conforming transportation 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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3.6 Using an interim emissions test to determine 2012 PM2.s conformity
As mentioned in Sections 3.2 and 3.3, some 2012 PM2.5 NAAQS areas will need to use
one of the interim emissions tests (40 CFR 93.119(d)). For example, an interim
emissions test must be used if an area does not have adequate or approved budgets for
any PIVh.s NAAQS that it can use for an analysis year. This is expected to be the case for
all analysis years of the conformity determination in 2012 PM2.5 NAAQS areas that are
"brand new" to PM2.5 conformity (that is, have not previously been designated
nonattainment for any previous PM2.5NAAQS (40 CFR 93.109(c)(3))). The relevant
interim emissions tests include the no-greater-than form of the build/no-build test and
baseline year test.
3.7 Baseline year for the baseline year test
For any NAAQS promulgated after 1997, the conformity rule at 40 CFR 93.119(e)(4)
defines the baseline year for the baseline year test as the most recent year for which
EPA's Air Emissions Reporting Rule requires submission of on-road mobile source
emissions inventories as of the effective date of designations.17 For the 2012 PIVh.s
NAAQS, this year is 2014. Conformity determinations using the baseline year test as an
interim emissions test must therefore use 2014 as the baseline year. See
www.epa.gov/otaq/stateresources/transconf/baseline.htm for more information on
baseline years.
Note that the baseline year emissions need to be modeled rather than interpolated, based
on the latest planning assumptions, latest emissions model and appropriate methods for
estimating travel and speeds as required by 40 CFR 93.110, 93.111, and 93.122. See
Section 4.1 for more information about emissions models to be used when implementing
the 2012 PM2.5 NAAQS.
3.8 Analysis years for 2012 PM2.s conformity
The years required to be analyzed for 2012 PIVh.s conformity depends on what test(s) are
being used to demonstrate conformity for a particular area.
When using the budget test
When using the budget test for the 2012 PM2.5 NAAQS, 40 CFR 93.122(d)(2) requires
the regional emissions analysis to be performed for:
• The attainment year for the 2012 PIVh.s NAAQS, if it is within the timeframe of
the transportation plan and conformity determination,
• The last year of the timeframe of the conformity determination, and
• Intermediate years as necessary, such that analysis years are no more than ten
years apart.
This change was made in the final Conformity Restructuring Rule (77 FR 14979).
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Note that the analysis years chosen must meet 40 CFR 93.118(d)(2) for all NAAQS that
apply. During the one-year grace period for newly designated 2012 PM2.5 areas when the
1997 or 2006 PM2.s NAAQS also applies18, the 2012 PM2.s areas with adequate or
approved 1997 or 2006 PM2.5 SIP budgets can determine conformity for both of these
NAAQS at the same time.
In addition, in areas that have budgets for a previous PlVb.5 NAAQS that are established
for years in the timeframe of the conformity determination, consistency with those
budgets must also be determined (40 CFR 93.118(b)). This consistency can be
demonstrated by interpolating between the years for which regional emissions analyses
are performed (40 CFR 93.118(d)(2)).19
When using an interim emissions test
Regardless of whether the area uses the baseline year test or the build/no-build test, the
required analysis years when using an interim emissions test, based on 40 CFR
93.119(g)(l), are:
• A year no more than 5 years beyond the year in which the conformity
determination is being made;
• The last year of the timeframe of the conformity determination, and
• Intermediate years as necessary, such that analysis years are not more than ten
years apart.
When using a combination of both the budget test and an interim emissions test
In cases when both the budget test and an interim emissions test are used to demonstrate
conformity to the 2012 PIVh.s NAAQS, the interagency consultation process must be used
to determine which analysis years should be selected for regional emissions analyses.
This situation may occur either because budgets are not available for some analysis
years20 or because budgets do not cover the entire 2012 PIVh.s area. The area may choose
analysis years that satisfy both the budget and interim emissions test requirements (40
CFR93.118(d)(2)and93.119(g)(l)).
The EPA Regional Office is available to discuss what analysis years apply in different
situations. See EPA contact information in Section 1.3.
18 If an area has both 1997 and 2006 PM2 5 NAAQS, the area should consult with their EPA Regional
Office.
19 Interpolating emissions for a particular year is only possible when an analysis has been done for a year
earlier and a year later than that year.
20 There can be limited cases where an area has a budget for another NAAQS of the same pollutant that
cannot be used for all analysis years because it is established for a later year. When this occurs, the interim
emissions test would be used for analysis years that are earlier than the budget year. For example, suppose
there is a 2012 PM25 area that is a Scenario 1 area. This area has 1997 PM25 NAAQS maintenance budgets
for the year 2022, and that is the only year for which PM2 5 budgets exist. In this case, the 2012 PM2 5 area
must use the budget test according to 40 CFR 93.118 for 2022 and later years, and the interim emissions
test according to 40 CFR 93.119 for analysis years earlier than 2022.
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3.9 Examples for 2012 PM2.s conformity determinations
Below are two hypothetical examples of how an area would apply the conformity tests.
In one example the area has SIP budgets for the 1997 PM2.s NAAQS and in the second
example the area does not have budgets for any PM2.s NAAQS.
Example 1
A 1997 PM2.5 nonattainment area is designated nonattainment for the 2012 PM2.s
NAAQS and is a Scenario 1 area (i.e., the boundaries of the 1997 PM2.s NAAQS and
2012 PM2.s NAAQS areas are identical). The attainment date for the 2012 PM2.5 NAAQS
is December 31, 2021. The area has 1997 PM2.s budgets from an approved maintenance
plan for 2020.
In March 2016, the MPO is making a conformity determination for both the 1997 and
2012 PM2.5 NAAQS for its transportation plan and TIP. The transportation plan runs
through 2040. In addition to needing to analyze 2021 (its attainment year for the 2012
PM2.5 NAAQS) and 2040 (the last year of the timeframe of the conformity
determination). The area analyzes 2020 because it is the budget year from the 1997
maintenance plan and, the area decides to analyze 2030 (an intermediate year so that
analysis years are no more than 10 years apart).
This table summarizes how the conformity tests would be done for this example:
Year
2020
2021
2030
2040
Analysis Required? (40 CFR 93.118(d)(2))
Yes -budget year for 1997 PM2.5 NAAQS
Yes - attainment year for 2012 PM2.5 NAAQS
Yes - intermediate year
Yes - last year of the transportation plan
Test Used
1997 PM2.5 budgets for 2020
1997 PM2.5 budgets for 2020
1997 PM2.5 budgets for 2020
1997 PM2.5 budgets for 2020
Example 2
An area is designated nonattainment for the 2012 PM2.s NAAQS. This area was not
designated nonattainment for any prior PM2.s NAAQS and therefore does not have any
previous PM2.s SIP budgets.
It is March 2016 and this area is making its initial 2012 PM2.s conformity determination
for its transportation plan and TIP. The transportation plan ends in 2040. In addition to
needing to analyze 2040 (the last year of the timeframe of the conformity determination),
the area decides to analyze 2020 (a year within five years of the year the conformity
determination is being made) and 2030 (an intermediate year so that analysis years are no
more than 10 years apart).
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This table summarizes how the conformity tests would be done for this example:
Year
2020
2030
2040
Analysis Required? (40 CFR
93.119(g))
Yes - a year within five years of the year
the conformity determination is being
made
Yes - intermediate year
Yes - last year of the transportation plan
Test Used
The build-no-greater-than-no-
build test or
The no-greater-than-baseline year
emissions test
Same selection as above
Same selection as above
Note that only one of the interim emissions tests is required. The area would select from
the two available tests and use the same test for all the analysis years.
3.10 Relying on a previous PMi.s regional emissions analysis when making a
conformity determination for the 2012 PMi.sNAAQS
A 2012 PM2.5 NAAQS area can rely upon a regional emissions analysis completed for the
1997 PM2.5 NAAQS, provided that it meets the requirements in 40 CFR 93.122(g). In
particular, the regionally significant projects in the transportation plan/TIP must be
consistent with those assumed in the previous regional emissions analysis, and the design
concept and scope of each regionally significant project cannot be significantly different
from that assumed in the previous regional emissions analysis. In addition, the previous
regional emissions analysis must be consistent with the requirements of 40 CFR 93.118
or 93.119, as appropriate. In particular, if the budget test is being performed, the 2012
PM2.5 attainment year must be included as an analysis year, and the regional emissions
analysis must demonstrate conformity to all currently applicable budgets.
If the previous emissions analysis did not analyze the 2012 PM2.5 NAAQS attainment
year, the area would, at a minimum, have to perform a new analysis for the new
attainment year. If nothing else has changed for analysis years examined in the last
conformity determination and emissions would be exactly the same as what would be
generated if a new analysis was performed (i.e., the planned projects, latest planning
assumptions, and emissions models have not changed), the modeling for those analysis
years would not have to be repeated. In these cases, an area could include the applicable
analyses from the previous conformity determination in its new determination.
Note that relying the previous regional emissions analysis may satisfy the 12-month grace
period to make a conformity determination for the 2012 PM2.5 NAAQS; however, it
does not reset the 4-year frequency clock in 40 CFR 93.104 required to determine
conformity for transportation plans and TIPs.
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Section 4. Emissions Models to Be Used When Implementing the 2012
PM25NAAQS
4.1 What emissions model do I use when completing 2012 PM2.sNAAQS
conformity determinations?
The conformity rule requires that conformity determinations must be based on the latest
emissions model available (40 CFR 93.111). This requirement can be met through the
use of the latest emission model approved by EPA, as explained below.
Using MOVES2014 and Subsequent Revisions
In October 7, 2014, EPA announced the release of the latest update of the MOVES2014
(MOtor Vehicle Emissions Simulator) (79 FR 60343). Upon the release of MOVES2014,
EPA established a two-year grace period before MOVES was to be used for regional
conformity determinations. In November 2015, EPA released MOVESZOHa which allows
MOVES users to benefit from several improvements to the model. MOVESZOHa does not
significantly change the criteria pollutant emissions results of MOVESZ014 and therefore is
not considered a new model for SIP and transportation conformity purposes.
Until October 7, 2016, areas can still use MOVES2010, MOVES2010a, or
MOVES2010b for conformity determinations, including conformity determinations for
the 2012 PM2.5 NAAQS. Given that the first conformity determination for this NAAQS
is due before the end of the MOVES2014 grace period, these areas can choose either
MOVES2014a, MOVES2014, MOVES2010a or MOVES2010b for this first conformity
determination.
Areas with budgets for a previous PM2.5 NAAQS that were prepared using MOBILE or
previous versions of MOVES should consider the impacts of needing to use
MOVES2014/MOVES2014a for future transportation plan and TIP conformity
determinations. Through interagency consultation, these areas can decide whether and
when SIPs and budgets can be revised with MOVES2014/MOVES2014a (or
transportation plan and TIPs can be revised, as appropriate) prior to the end of the
regional conformity grace period.
MOVES2014 (and any subsequent minor updates) will be the latest emission model for
new regional conformity analyses for the 2012 PM2.5 NAAQS areas outside of California
that begin after October 7, 2016 (or when EPA finds adequate or approves MOVES2014-
based budgets that will be used for conformity for the 2012 PM2.5 NAAQS, whichever
comes first. These budgets could be for the 1997, 2006, or 2012 PM2.s NAAQS in an
area, as described above in Section 3.3.
For further information on the implementation of the MOVES regional conformity grace
period and the use of MOVES for SIP development, see EPA's "Policy Guidance on the
Use of MOVES2014 for State Implementation Plan Development, Transportation
Conformity, and Other Purposes" (EPA-420-B-14-008, July 2014), available online at:
www.epa.gov/otaq/stateresources/transconf/policy.htmtfmodels.
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Using EMFAC2011
EMFAC2011 is currently the latest approved model for use in transportation conformity
analyses in California and should be used for all regional conformity analyses for the
2012 PM2.5NAAQS until EPA announces otherwise.
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