```

[Federal Register Volume 78, Number 127 (Tuesday, July 2, 2013)]
[Proposed Rules]
[Pages 39654-39670]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-15887]

[[Page 39654]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R05-OAR-2011-0673; FRL-9830-2]

Approval, and Promulgation of Air Quality Implementation Plans; 
Michigan; Redesignation of the Detroit-Ann Arbor Area to Attainment of 
the 1997 Annual Standard and the 2006 24-Hour Standard for Fine 
Particulate Matter

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: On July 5, 2011, the Michigan Department of Environmental 
Quality (MDEQ) submitted a request for EPA to redesignate the Detroit-
Ann Arbor Michigan nonattainment area (Livingston, Macomb, Monroe, 
Oakland, St. Clair, Washtenaw, and Wayne Counties), referred to as the 
Detroit-Ann Arbor area, to attainment of the Clean Air Act (CAA or Act) 
1997 annual and the 2006 24-hour national ambient air quality standards 
(NAAQS or standard) for fine particulate matter (PM2.5). EPA 
is proposing to redesignate the area. EPA is also proposing several 
additional related actions. EPA is proposing to determine that the 
entire Detroit-Ann Arbor area continues to attain both the annual and 
24-hour PM2.5 standards. EPA is proposing to approve, as 
revisions to the Michigan state implementation plan (SIP), the state's 
plan for maintaining the 1997 annual and the 2006 24-hour 
PM2.5 NAAQS through 2022 in the area. EPA previously 
approved the base year emissions inventory for the Detroit-Ann Arbor 
area, which met the comprehensive emissions inventory requirement of 
the Act. Michigan's maintenance plan submission includes a budget for 
the mobile source contribution of PM2.5 and nitrogen oxides 
(NOX) to the Detroit-Ann Arbor Michigan PM2.5 
area for transportation conformity purposes, which EPA is proposing to 
approve. EPA is proposing to take this action in accordance with the 
CAA and EPA's implementation regulations regarding the 1997 and the 
2006 PM2.5 NAAQS.

DATES: Comments must be received on or before August 1, 2013.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R05-
OAR-2011-0673, by one of the following methods:
    1. www.regulations.gov: Follow the on-line instructions for 
submitting comments.
    2. Email: blakley.pamela@epa.gov.
    3. Fax: (312) 886-4447.
    4. Mail: Pamela Blakley, Chief, Control Strategies Section (AR-
18J), U.S. Environmental Protection Agency, 77 West Jackson Boulevard, 
Chicago, Illinois 60604.
    5. Hand Delivery: Pamela Blakley, Chief, Control Strategies Section 
(AR-18J), U.S. Environmental Protection Agency, 77 West Jackson 
Boulevard, Chicago, Illinois 60604. Such deliveries are only accepted 
during the Regional Office normal hours of operation, and special 
arrangements should be made for deliveries of boxed information. The 
Regional Office official hours of business are Monday through Friday, 
8:30 a.m. to 4:30 p.m. excluding Federal holidays.
    Instructions: Direct your comments to Docket ID No. EPA-R05-OAR-
2011-0673. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
www.regulations.gov, including any personal information provided, 
unless the comment includes information claimed to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Do not submit information that you consider to 
be CBI or otherwise protected through www.regulations.gov or email. The 
www.regulations.gov Web site is an ``anonymous access'' system, which 
means EPA will not know your identity or contact information unless you 
provide it in the body of your comment. If you send an email comment 
directly to EPA without going through www.regulations.gov your email 
address will be automatically captured and included as part of the 
comment that is placed in the public docket and made available on the 
Internet. If you submit an electronic comment, EPA recommends that you 
include your name and other contact information in the body of your 
comment and with any disk or CD-ROM you submit. If EPA cannot read your 
comment due to technical difficulties and cannot contact you for 
clarification, EPA may not be able to consider your comment. Electronic 
files should avoid the use of special characters, any form of 
encryption, and be free of any defects or viruses. For additional 
instructions on submitting comments, go to Section I of the 
SUPPLEMENTARY INFORMATION section of this document.
    Docket: All documents in the docket are listed in the 
www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in www.regulations.gov or in hard copy at the Environmental Protection 
Agency, Region 5, Air and Radiation Division, 77 West Jackson 
Boulevard, Chicago, Illinois 60604. This facility is open from 8:30 
a.m. to 4:30 p.m., Monday through Friday, excluding Federal holidays. 
We recommend that you telephone Carolyn Persoon, Environmental 
Engineer, at (312) 353-8290 before visiting the Region 5 office.

FOR FURTHER INFORMATION CONTACT: Carolyn Persoon, Environmental 
Engineer, Control Strategies Section, Air Programs Branch (AR-18J), 
Environmental Protection Agency, Region 5, 77 West Jackson Boulevard, 
Chicago, Illinois 60604, (312) 353-8290, persoon.carolyn@epa.gov.

SUPPLEMENTARY INFORMATION: This supplementary information section is 
arranged as follows:

I. What should I consider as I prepare my comments for EPA?
II. What actions is EPA proposing to take?
III. What is the background for these actions?
IV. What are the criteria for redesignation to attainment?
V. What is EPA's analysis of the state's request?
    1. Attainment
    2. The Area Has Met All Applicable Requirements Under Section 
110 and Part D and Has a Fully Approved SIP Under Section 110(k) 
(Section 107(d)(3)(E)(ii) and (v))
    3. The Improvement in Air Quality Is Due to Permanent and 
Enforceable Reductions in Emissions Resulting From Implementation of 
the SIPs and Applicable Federal Air Pollution Control Regulations 
and Other Permanent and Enforceable Reductions (Section 
107(d)(3)(E)(iii))
    4. Michigan Has a Fully Approved Maintenance Plan Pursuant to 
Section 175A of the CAA (Section 107(d)(3)(E)(iv))
    5. Motor Vehicle Emissions Budget (MVEBs) for the Mobile Source 
Contribution to PM2.5 and NOX
    6. 2005 Comprehensive Emissions Inventory
    7. Summary of Proposed Actions
VI. What are the effects of EPA's proposed actions?
VII. Statutory and Executive Order Reviews

I. What should I consider as I prepare my comments for EPA?

    When submitting comments, remember to:
    1. Identify the rulemaking by docket number and other identifying 
information (subject heading, Federal Register date and page number).

[[Page 39655]]

    2. Follow directions--The EPA may ask you to respond to specific 
questions or organize comments by referencing a Code of Federal 
Regulations (CFR) part or section number.
    3. Explain why you agree or disagree; suggest alternatives and 
substitute language for your requested changes.
    4. Describe any assumptions and provide any technical information 
and/or data that you used.
    5. If you estimate potential costs or burdens, explain how you 
arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
    6. Provide specific examples to illustrate your concerns, and 
suggest alternatives.
    7. Explain your views as clearly as possible, avoiding the use of 
profanity or personal threats.
    8. Make sure to submit your comments by the comment period deadline 
identified.

II. What actions is EPA proposing to take?

    EPA is proposing to take several actions related to redesignation 
of the Detroit-Ann Arbor area to attainment for the 1997 annual and 
2006 24-hour PM2.5 NAAQS.
    EPA is proposing to approve Michigan's PM2.5 maintenance 
plan for the Detroit-Ann Arbor area as a revision to the Michigan SIP, 
including the motor vehicles emissions budget for PM2.5 and 
NOX for the mobile source contribution of the Michigan 
portion of the Detroit-Ann Arbor PM2.5 area. EPA's analysis 
for this proposed action is discussed in Section V. of today's proposed 
rulemaking.
    EPA has previously approved (77 FR 66547) the 2005 primary 
PM2.5, NOX, volatile organic compounds (VOCs), 
ammonia, and sulfur dioxide (SO2) base year emissions 
inventory which satisfied the requirement in section 172(c)(3) for a 
current, accurate and comprehensive emission inventory.
    EPA also is proposing to find that Michigan meets the requirements 
for redesignation of the Detroit-Ann Arbor area to attainment of the 
1997 annual and the 2006 24-hour PM2.5 NAAQS under section 
107(d)(3)(E) of the CAA. EPA is thus proposing to grant Michigan's 
request to change the designation of its portion of the Detroit-Ann 
Arbor area from nonattainment to attainment for the 1997 annual and the 
2006 24-hour PM2.5 NAAQS.

III. What is the background for these actions?

    Fine particulate pollution can be emitted directly from a source 
(primary PM2.5) or formed secondarily through chemical 
reactions in the atmosphere involving precursor pollutants emitted from 
a variety of sources. Sulfates are a type of secondary particulate 
formed from SO2 emissions from power plants and industrial 
facilities. Nitrates, another common type of secondary particulate, are 
formed from combustion emissions of NOX from power plants, 
mobile sources, and other combustion sources.
    The first air quality standards for PM2.5 were 
promulgated on July 18, 1997, at 62 FR 38652. EPA promulgated an annual 
standard at a level of 15 micrograms per cubic meter ([micro]g/m\3\) of 
ambient air, based on a three-year average of the annual mean 
PM2.5 concentrations at each monitoring site. In the same 
rulemaking, EPA promulgated a 24-hour PM2.5 standard of 65 
[micro]g/m\3\, based on a three-year average of the annual 98th 
percentile of 24-hour PM2.5 concentrations at each 
monitoring site.
    On January 5, 2005, at 70 FR 944, EPA published air quality area 
designations for the 1997 annual PM2.5 standard based on air 
quality data for calendar years 2001-2003. In that rulemaking, EPA 
designated the Detroit-Ann Arbor area (Livingston, Macomb, Monroe, 
Oakland, St. Clair, Washtenaw, and Wayne Counties) as nonattainment for 
the 1997 annual PM2.5 standard.
    On October 17, 2006, (71 FR 61144), EPA promulgated a 24-hour 
standard of 35 [micro]g/m\3\ based on a 3-year average of the 98th 
percentile of 24-hour concentration, as set forth at 40 CFR 50.13. On 
December 13, 2009, (74 FR 58688), EPA made designation determinations, 
as required by CAA section 107(d)(1), for the 2006 24-hour 
PM2.5 NAAQS. In that action, EPA designated the Detroit-Ann 
Arbor area as nonattainment for the 2006 24-hour PM2.5 
NAAQS.
    EPA's rulemaking promulgating the revised 24-hour standard retained 
as the 2006 annual PM2.5 standard the 1997 annual standard 
of 15 [micro]g/m\3\ (2006 annual PM2.5 standard). In 
response to legal challenges of the 2006 annual PM2.5 
standard, the U.S. Court of Appeals for District of Columbia Circuit 
(D.C. Circuit or Court) remanded this standard to EPA for further 
consideration. See American Farm Bureau Federation and National Pork 
Producers Council, et al. v. EPA, 559 F.3d 512 (D.C. Cir. 2009). 
However, given that the 1997 and 2006 annual PM2.5 standards 
are essentially identical, attainment of the 1997 annual 
PM2.5 standard would also indicate attainment of the 
remanded 2006 annual standard. Since the Detroit-Ann Arbor area is 
designated only for 1997 annual standard and not the 2006 annual 
standard, today's proposed actions address the 1997 annual and the 2006 
24-hour PM2.5 standards.
    In this proposed redesignation, EPA takes into account two 
decisions of the D.C. Circuit. On August 21, 2012, in EME Homer City 
Generation, L.P. v. EPA, 696 F.3d 7 (D.C. Cir. 2012), the D.C. Circuit 
vacated and remanded the Cross State Air Pollution Rule (CSAPR) and 
ordered EPA to continue administering the Clean Air Interstate Rule 
(CAIR) ``pending . . . development of a valid replacement.'' EME Homer 
City at 38. The D.C. Circuit denied all petitions for rehearing on 
January 24, 2013. In the second decision, on January 4, 2013, the D.C. 
Circuit remanded to EPA the ``Final Clean Air Fine Particle 
Implementation Rule'' (72 FR 20586, April 25, 2007) and the 
``Implementation of the New Source Review (NSR) Program for Particulate 
Matter Less than 2.5 Micrometers (PM2.5)'' final rule (73 FR 
28321, May 16, 2008). Natural Resources Defense Council v. EPA, 706 
F.3d 428 (D.C. Cir. 2013).

IV. What are the criteria for redesignation to attainment?

    The CAA sets forth the requirements for redesignating a 
nonattainment area to attainment. Specifically, section 107(d)(3)(E) of 
the CAA allows for redesignation provided that: (1) The Administrator 
determines that the area has attained the applicable NAAQS based on 
current air quality data; (2) the Administrator has fully approved an 
applicable SIP for the area under section 110(k) of the CAA; (3) the 
Administrator determines that the improvement in air quality is due to 
permanent and enforceable emission reductions resulting from 
implementation of the applicable SIP, Federal air pollution control 
regulations, or other permanent and enforceable emission reductions; 
(4) the Administrator has fully approved a maintenance plan for the 
area meeting the requirements of section 175A of the CAA; and (5) the 
state containing the area has met all requirements applicable to the 
area for purposes of redesignation under section 110 and part D of the 
CAA.

V. What is EPA's analysis of the state's request?

    EPA is proposing to approve the redesignation of the Detroit-Ann 
Arbor area to attainment of the 1997 annual PM2.5 NAAQS and 
is proposing to approve Michigan's maintenance plan for the area and 
other related SIP revisions. The bases for these actions follow.

[[Page 39656]]

1. Attainment

    In accordance with section 179(c) of the CAA, 42 U.S.C. 7509(c) and 
40 CFR 51.1004(c), EPA is proposing to determine that Detroit-Ann Arbor 
Michigan has attained the 1997 annual and the 2006 24-hour 
PM2.5 NAAQS. This proposed determination is based upon 
complete, quality-assured, and certified ambient air monitoring data 
for the 2009-2011 and 2010-2012 monitoring period that shows this area 
has monitored attainment of both PM2.5 NAAQS.
    Under EPA's regulations at 40 CFR 50.7, the annual primary and 
secondary PM2.5 standards are met when the annual arithmetic 
mean concentration, as determined in accordance with 40 CFR part 50, 
appendix N, is less than or equal to 15.0 [micro]g/m\3\ at all relevant 
monitoring sites in the area. Under EPA regulations in 40 CFR 50.13 and 
in accordance with 40 CFR part 50, appendix N, the 24-hour primary and 
secondary PM2.5 standards are met when the 98th percentile 
24-hour concentration is less than or equal to 35 [micro]g/m\3\.
    EPA has reviewed the ambient air quality monitoring data in the 
Detroit-Ann Arbor area, consistent with the requirements contained at 
40 CFR part 50. EPA's review focused on data recorded in the EPA Air 
Quality System (AQS) database for the Detroit-Ann Arbor area for 
PM2.5 nonattainment area from 2009-2011 and 2010-2012.
    The Detroit-Ann Arbor area had fourteen monitors located in Macomb, 
Monroe, Oakland, St. Clair, Washtenaw, and Wayne Counties that reported 
design values from 2010-2012 for PM2.5 that ranged from 8.4 
to 11.5 [mu]g/m\3\ for the 1997 annual standard and 22 to 28 [mu]g/m\3\ 
for the 2006 24-hour standard, as shown in Table 1.
    All monitors in the Detroit-Ann Arbor area recorded complete data 
in accordance with criteria set forth by EPA in 40 CFR part 50 appendix 
N, where a complete year of air quality data comprises four calendar 
quarters, with each quarter containing data from at least 75% capture 
of the scheduled sampling days. Data available are considered to be 
sufficient for comparison to the NAAQS if three consecutive complete 
years of data exist. Recently state certified data for 2010-2012 show 
the area continues to attain.

 Table 1--Annual and 24-hour PM2.5 Design Values for Detroit-Ann Arbor Area Monitors With Complete Data for the 2009-2011 and 2010-2012 Design Values in
                                                                       [mu]g/m\3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                   Annual standard  24-Hour standard   Annual standard  24-Hour standard
                   County                                  Monitor                2009-2011 ([mu]g/ 2009-2011 ([mu]g/ 2010-2012 ([mu]g/ 2010-2012 ([mu]g/
                                                                                        m\3\)             m\3\)             m\3\)             m\3\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Macomb.....................................  New Haven 260990009................               9.0                25               8.4                22
Monroe.....................................  Luna Pier 261150005................               9.9                24               9.2                24
Oakland....................................  Oak Park 261250001.................               9.4                27               8.8                24
St. Clair..................................  Port Huron 261470005...............               9.3                26               9.6                25
Washtenaw..................................  Ypsilanti 261610008................               9.6                25               9.3                25
Wayne......................................  Allen Park 261630001...............              10.5                27               9.2                24
                                             Dearborn 261630033.................              11.6                32               9.3                23
                                             E 7 Mile 261630019.................               9.9                27              10.2                25
                                             FIA 261630039......................              10.4                28              10.9                25
                                             Linwood 261630016..................              10.1                28              10.0                26
                                             Livonia 261630025..................               9.5                26               9.7                28
                                             Newberry 261630038.................              10.3                27               9.4                24
                                             SW HS 261630015....................              10.9                28              11.5                28
                                             Wyandotte 261630036................               9.6                24               9.2                22
--------------------------------------------------------------------------------------------------------------------------------------------------------

    EPA has found that the Detroit-Ann Arbor area has attained both the 
1997 annual and the 2006 24-hour PM2.5 NAAQs, and has 
attained the standards by the attainment date.

2. The Area Has Met All Applicable Requirements Under Section 110 and 
Part D and Has a Fully Approved SIP Under Section 110(k) (Section 
107(d)(3)(E)(ii) and (v))

    We have determined that Michigan has met all currently applicable 
SIP requirements for purposes of redesignation for the Detroit-Ann 
Arbor area under section 110 of the CAA (general SIP requirements). We 
are also proposing to find that the Michigan submittal meets all SIP 
requirements currently applicable for purposes of redesignation under 
part D of title I of the CAA, in accordance with section 
107(d)(3)(E)(v). In addition, we are proposing to find that all 
applicable requirements of the Michigan SIP for purposes of 
redesignation have been approved, in accordance with section 
107(d)(3)(E)(ii). As discussed above, EPA previously approved 
Michigan's 2005 emissions inventory as meeting the section 172(c)(3) 
comprehensive emissions inventory requirement.
    In making these proposed determinations, we have ascertained which 
SIP requirements are applicable for purposes of redesignation, and 
concluded that the Michigan SIP includes measures meeting those 
requirements and that they are fully approved under section 110(k) of 
the CAA.
a. Michigan Has Met All Applicable Requirements for Purposes of 
Redesignation of the Detroit-Ann Arbor Area Under Section 110 and Part 
D of the CAA
i. Section 110 General SIP Requirements
    Section 110(a) of title I of the CAA contains the general 
requirements for a SIP. Section 110(a)(2) provides that the 
implementation plan submitted by a state must have been adopted by the 
state after reasonable public notice and hearing, and, among other 
things, must: include enforceable emission limitations and other 
control measures, means or techniques necessary to meet the 
requirements of the CAA; provide for establishment and operation of 
appropriate devices, methods, systems, and procedures necessary to 
monitor ambient air quality; provide for implementation of a source 
permit program to regulate the modification

[[Page 39657]]

and construction of any stationary source within the areas covered by 
the plan; include provisions for the implementation of part C, 
Prevention of Significant Deterioration (PSD) and part D, NSR permit 
programs; include criteria for stationary source emission control 
measures, monitoring, and reporting; include provisions for air quality 
modeling; and provide for public and local agency participation in 
planning and emission control rule development.
    Section 110(a)(2)(D) of the CAA requires that SIPs contain measures 
to prevent sources in a state from significantly contributing to air 
quality problems in another state. EPA believes that the requirements 
linked with a particular nonattainment area's designation are the 
relevant measures to evaluate in reviewing a redesignation request. The 
transport SIP submittal requirements, where applicable, continue to 
apply to a state regardless of the designation of any one particular 
area in the state. Thus, we believe that these requirements should not 
be construed to be applicable requirements for purposes of 
redesignation.
    Further, we believe that the other section 110 elements described 
above that are not connected with nonattainment plan submissions and 
not linked with an area's attainment status are also not applicable 
requirements for purposes of redesignation. A state remains subject to 
these requirements after an area is redesignated to attainment. We 
conclude that only the section 110 and part D requirements that are 
linked with a particular area's designation are the relevant measures 
which we may consider in evaluating a redesignation request. See 
Reading, Pennsylvania, proposed and final rulemakings (61 FR 53174-
53176 (October 10, 1996)) and (62 FR 24826 (May 7, 1997)); Cleveland-
Akron-Lorain, Ohio, final rulemaking (61 FR 20458 (May 7, 1996)); and 
Tampa, Florida, final rulemaking (60 FR 62748 (December 7, 1995)). See 
also the discussion on this issue in the Cincinnati, Ohio 1-hour ozone 
redesignation (65 FR 37890 (June 19, 2000)), and in the Pittsburgh, 
Pennsylvania 1-hour ozone redesignation (66 FR 50399 (October 19, 
2001)).
    We have reviewed the Michigan SIP and have concluded that it meets 
the general SIP requirements under section 110 of the CAA to the extent 
they are applicable for purposes of redesignation. EPA has previously 
approved provisions of Michigan's SIP addressing section 110 
requirements (including provisions addressing particulate matter), at 
40 CFR 52.1173.
    On December 6, 2007, September 19, 2008, and April 6, 2011, 
Michigan made submittals addressing ``infrastructure SIP'' elements 
required under CAA section 110(a)(2). EPA finalized approval of the 
December 6, 2007, submittal on July 13, 2011, at 76 FR 41075. An August 
15, 2011, submittal for the 2006 standard was approved on October 29, 
2012 (77 FR 65478). The requirements of section 110(a)(2), however, are 
statewide requirements that are not linked to the PM2.5 
nonattainment status of the Detroit-Ann Arbor area. Therefore, EPA 
believes that these SIP elements are not applicable requirements for 
purposes of review of the state's PM2.5 redesignation 
request.
ii. Part D Requirements
    EPA has determined that, upon approval of the base year emissions 
inventories discussed in section IV.C. of this rulemaking, the Michigan 
SIP will meet the applicable SIP requirements for the Detroit-Ann Arbor 
area applicable for purposes of redesignation under part D of the CAA. 
Subpart 1 of part D, found in sections 172-176 of the CAA, sets forth 
the basic nonattainment requirements applicable to all nonattainment 
areas.

1. Subpart 1

(a) Section 172 Requirements
    For purposes of evaluating this redesignation request, the 
applicable section 172 SIP requirements for the Detroit-Ann Arbor area 
are contained in sections 172(c)(1)-(9). A thorough discussion of the 
requirements contained in section 172 can be found in the General 
Preamble for Implementation of Title I (57 FR 13498, April 16, 1992).
    Section 172(c)(1) requires the plans for all nonattainment areas to 
provide for the implementation of all reasonably available control 
measures (RACM) as expeditiously as practicable and to provide for 
attainment of the primary NAAQS. EPA interprets this requirement to 
impose a duty on all states to consider all available control measures 
for all nonattainment areas and to adopt and implement such measures as 
are reasonably available for implementation in each area as components 
of the area's attainment demonstration. Because the Detroit-Ann Arbor 
area has reached attainment, Michigan does not need to address 
additional measures to provide for attainment, and section 172(c)(1) 
requirements are no longer considered to be applicable as long as the 
area continues to attain the standard until redesignation. (40 CFR 
51.918).
    The reasonable further progress (RFP) requirement under section 
172(c)(2) is defined as progress that must be made toward attainment. 
This requirement is not relevant for purposes of the Detroit-Ann Arbor 
redesignation because the area has monitored attainment of the 1997 
annual PM2.5 NAAQS. (General Preamble, 57 FR 13564). See 
also 40 CFR 51.918. The requirement to submit the section 172(c)(9) 
contingency measures is similarly not applicable for purposes of 
redesignation. Id.
    Section 172(c)(3) requires submission and approval of a 
comprehensive, accurate and current inventory of actual emissions. 
Michigan submitted a 2005 base year emissions inventory in the required 
attainment plan. As discussed previously, and below in section IV.C., 
EPA approved the 2005 base year inventory as meeting the section 
172(c)(3) emissions inventory requirement for the Detroit-Ann Arbor 
area on November 6,2012 (77 FR 66547).
    Section 172(c)(4) requires the identification and quantification of 
allowable emissions for major new and modified stationary sources in an 
area, and section 172(c)(5) requires source permits for the 
construction and operation of new and modified major stationary sources 
anywhere in the nonattainment area. EPA approved Michigan's current NSR 
program on January 27, 1982 (47 FR 3764), but has not approved updates 
since that time. Nonetheless, since PSD requirements will apply after 
redesignation, the area need not have a fully-approved NSR program for 
purposes of redesignation, provided that the area demonstrates 
maintenance of the NAAQS without part D NSR. A detailed rationale for 
this view is described in a memorandum from Mary Nichols, Assistant 
Administrator for Air and Radiation, dated October 14, 1994, entitled, 
``Part D New Source Review Requirements for Areas Requesting 
Redesignation to Attainment.'' Michigan has demonstrated that the 
Detroit-Ann Arbor area will be able to maintain the standard without 
part D NSR in effect; therefore, the state need not have a fully 
approved part D NSR program prior to approval of the redesignation 
request. The state's PSD program will become effective in the Detroit-
Ann Arbor area upon redesignation to attainment. See rulemakings for 
Detroit, Michigan (60 FR 12467-12468, March 7, 1995); Cleveland-Akron-
Lorain, Ohio (61 FR 20458, 20469-20470, May 7, 1996); Louisville, 
Kentucky (66 FR 53665, October 23, 2001); and Grand Rapids,

[[Page 39658]]

Michigan (61 FR 31834-31837, June 21, 1996).
    Section 172(c)(6) requires the SIP to contain control measures 
necessary to provide for attainment of the standard. Because attainment 
has been reached, no additional measures are needed to provide for 
attainment.
    Section 172(c)(7) requires the SIP to meet the applicable 
provisions of section 110(a)(2). As noted above, we believe the 
Michigan's SIP meets the applicable requirements of section 110(a)(2) 
for purposes of redesignation.
(b) Section 176 Conformity Requirements
    Section 176(c) of the CAA requires states to establish criteria and 
procedures to ensure that Federally-supported or funded activities, 
including highway projects, conform to the air quality planning goals 
in the applicable SIPs. The requirement to determine conformity applies 
to transportation plans, programs and projects developed, funded or 
approved under Title 23 of the U.S. Code and the Federal Transit Act 
(transportation conformity) as well as to all other Federally-supported 
or funded projects (general conformity). State transportation 
conformity regulations must be consistent with Federal conformity 
regulations relating to consultation, enforcement, and enforceability, 
which EPA promulgated pursuant to CAA requirements.
    EPA approved Michigan's general and transportation conformity SIPs 
on December 18, 1996 (61 FR 666079 and 61 FR 66609, respectively). 
Michigan has submitted an on-road motor vehicle emissions budget (MVEB) 
for the Detroit-Ann Arbor area calculated by the local metropolitan 
planning organization (MPO), SEMCOG. The area must use the MVEB from 
the maintenance plan in any conformity determination that is effective 
on or after the effective date of the maintenance plan approval.

2. Effect of the January 4, 2013, DC Circuit Decision Regarding 
PM2.5 Implementation Under Subpart 4

a. Background
    As discussed above, on January 4, 2013, in Natural Resources 
Defense Council v. EPA, the DC Circuit remanded to EPA the ``Final 
Clean Air Fine Particle Implementation Rule'' (72 FR 20586, April 25, 
2007) and the ``Implementation of the New Source Review (NSR) Program 
for Particulate Matter Less than 2.5 Micrometers (PM2.5)'' 
final rule (73 FR 28321, May 16, 2008) (collectively, ``1997 
PM2.5 Implementation Rule''). 706 F.3d 428 (DC Cir. 2013). 
The Court found that EPA erred in implementing the 1997 
PM2.5 NAAQS pursuant to the general implementation 
provisions of subpart 1 of part D of title I of the CAA, rather than 
the particulate-matter-specific provisions of subpart 4 of part D of 
title I. Although the Court's ruling did not directly address the 2006 
PM2.5 standard, EPA is taking into account the Court's 
position on subpart 4 and the 1997 PM2.5 standard in 
evaluating redesignations for the 2006 standard.
b. Proposal on This Issue
    EPA is proposing to determine that the Court's January 4, 2013, 
decision does not prevent EPA from redesignating the Detroit-Ann Arbor 
area to attainment. Even in light of the Court's decision, 
redesignation for this area is appropriate under the CAA and EPA's 
longstanding interpretations of the CAA's provisions regarding 
redesignation. EPA's longstanding interpretation is that requirements 
that are imposed, or that become due, after a complete redesignation 
request is submitted for an area that is attaining the standard are not 
applicable for purposes of evaluating a redesignation request. Second, 
even if EPA applies the subpart 4 requirements to the Detroit-Ann Arbor 
redesignation request and disregards the provisions of its 1997 
PM2.5 implementation rule recently remanded by the Court, 
the state's request for redesignation of this area still qualifies for 
approval. EPA's discussion takes into account the effect of the Court's 
ruling on the area's maintenance plan, which EPA views as approvable 
when subpart 4 requirements are considered.
i. Applicable Requirements for Purposes of Evaluating the Redesignation 
Request
    With respect to the 1997 PM2.5 Implementation Rule, the 
Court's January 4, 2013, ruling rejected EPA's reasons for implementing 
the PM2.5 NAAQS solely in accordance with the provisions of 
subpart 1, and remanded that matter to EPA, so that it could address 
implementation of the 1997 PM2.5 NAAQS under subpart 4 of 
part D of the CAA, in addition to subpart 1. For the purposes of 
evaluating Michigan's redesignation request for the area, to the extent 
that implementation under subpart 4 would impose additional 
requirements for areas designated nonattainment, EPA believes that 
those requirements are not ``applicable'' for the purposes of CAA 
section 107(d)(3)(E), and thus EPA is not required to consider subpart 
4 requirements with respect to the Detroit-Ann Arbor redesignation. 
Under its longstanding interpretation of the CAA, EPA has interpreted 
section 107(d)(3)(E) to mean that the part D provisions which are 
``applicable'' and which must be approved in order for EPA to 
redesignate an area include only those which came due prior to a 
state's submittal of a complete redesignation request. See ``Procedures 
for Processing Requests to Redesignate Areas to Attainment,'' 
Memorandum from John Calcagni, Director, Air Quality Management 
Division, September 4, 1992 (Calcagni memorandum). See also ``State 
Implementation Plan (SIP) Requirements for Areas Submitting Requests 
for Redesignation to Attainment of the Ozone and Carbon Monoxide (CO) 
NAAQS on or after November 15, 1992,'' Memorandum from Michael Shapiro, 
Acting Assistant Administrator, Air and Radiation, September 17, 1993 
(Shapiro memorandum); Final Redesignation of Detroit-Ann Arbor, (60 FR 
12459, 12465-66, March 7, 1995); Final Redesignation of St. Louis, 
Missouri, (68 FR 25418, 25424-27, May 12, 2003); Sierra Club v. EPA, 
375 F.3d 537, 541 (7th Cir. 2004) (upholding EPA's redesignation 
rulemaking applying this interpretation and expressly rejecting Sierra 
Club's view that the meaning of ``applicable'' under the statute is 
``whatever should have been in the plan at the time of attainment 
rather than whatever actually was in the plan and already implemented 
or due at the time of attainment'').\1\ In this case, at the time that 
Michigan submitted its redesignation request, requirements under 
subpart 4 were not due, (and indeed, were not yet known to apply.)
---------------------------------------------------------------------------

    \1\ Applicable requirements of the CAA that come due subsequent 
to the area's submittal of a complete redesignation request remain 
applicable until a redesignation is approved, but are not required 
as a prerequisite to redesignation. Section 175A(c) of the CAA.
---------------------------------------------------------------------------

    EPA's view that, for purposes of evaluating the Detroit-Ann Arbor 
redesignation, the subpart 4 requirements were not due at the time the 
state submitted the redesignation request is in keeping with the EPA's 
interpretation of subpart 2 requirements for subpart 1 ozone areas 
redesignated subsequent to the D.C. Circuit's decision in South Coast 
Air Quality Mgmt. Dist. v. EPA, 472 F.3d 882 (D.C. Cir. 2006). In South 
Coast, the Court found that EPA was not permitted to implement the 1997 
8-hour ozone standard solely under subpart 1, and held that EPA was 
required under the statute to implement the standard under the ozone-
specific requirements of subpart 2 as well. Subsequent to the South 
Coast decision,

[[Page 39659]]

in evaluating and acting upon redesignation requests for the 1997 8-
hour ozone standard that were submitted to EPA for areas under subpart 
1, EPA applied its longstanding interpretation of the CAA that 
``applicable requirements'', for purposes of evaluating a 
redesignation, are those that had been due at the time the 
redesignation request was submitted. See, e.g., Proposed Redesignation 
of Manitowoc County and Door County Nonattainment Areas (75 FR 22047, 
22050, April 27, 2010). In those actions, EPA therefore did not 
consider subpart 2 requirements to be ``applicable'' for the purposes 
of evaluating whether the area should be redesignated under section 
107(d)(3)(E).
    EPA's interpretation derives from the provisions of CAA Section 
107(d)(3). Section 107(d)(3)(E)(v) states that, for an area to be 
redesignated, a state must meet ``all requirements `applicable' to the 
area under section 110 and part D.'' Section 107(d)(3)(E)(ii) provides 
that the EPA must have fully approved the ``applicable'' SIP for the 
area seeking redesignation. These two sections read together support 
EPA's interpretation of ``applicable'' as only those requirements that 
came due prior to submission of a complete redesignation request. 
First, holding states seeking redesignation to an ongoing obligation to 
adopt new CAA requirements that arose after the state submitted its 
redesignation request would make it problematic or impossible for EPA 
to act on redesignation requests in accordance with the 18-month 
deadline Congress set for EPA action in section 107(d)(3)(D). If 
``applicable requirements'' were interpreted to be a continuing flow of 
requirements with no reasonable limitation, states, after submitting a 
redesignation request, would be forced continuously to make additional 
SIP submissions that in turn would require EPA to undertake further 
notice-and-comment rulemaking actions to act on those submissions. This 
would create a regime of unceasing rulemaking that would delay action 
on the redesignation request beyond the 18-month timeframe provided by 
the CAA for this purpose.
    Second, a fundamental premise for redesignating a nonattainment 
area to attainment is that the area has attained the relevant NAAQS due 
to emission reductions from existing controls. Thus, an area for which 
a redesignation request has been submitted would have already attained 
the NAAQS as a result of satisfying statutory requirements that came 
due prior to the submission of the request. Absent a showing that 
unadopted and unimplemented requirements are necessary for future 
maintenance, it is reasonable to view the requirements applicable for 
purposes of evaluating the redesignation request as including only 
those SIP requirements that have already come due. These are the 
requirements that led to attainment of the NAAQS. To require, for 
redesignation approval, that a state also satisfy additional SIP 
requirements coming due after the state submits its complete 
redesignation request, and while EPA is reviewing it, would compel the 
state to do more than is necessary to attain the NAAQS, without a 
showing that the additional requirements are necessary for maintenance.
    In the context of this redesignation, the timing and nature of the 
Court's January 4, 2013, decision in NRDC v. EPA compound the 
consequences of imposing requirements that come due after the 
redesignation request is submitted. The state submitted its 
redesignation request on July 5, 2011, but the Court did not issue its 
decision remanding EPA's 1997 PM2.5 implementation rule 
concerning the applicability of the provisions of subpart 4 until 
January 2013.
    To require the state's fully-completed and pending redesignation 
request to comply now with requirements of subpart 4 that the Court 
announced only in January 2013, would be to give retroactive effect to 
such requirements when the state had no notice that it was required to 
meet them. The D.C. Circuit recognized the inequity of this type of 
retroactive impact in Sierra Club v. Whitman, 285 F.3d 63 (D.C. Cir. 
2002),\2\ where it upheld the District Court's ruling refusing to make 
retroactive EPA's determination that the St. Louis area did not meet 
its attainment deadline. In that case, petitioners urged the Court to 
make EPA's nonattainment determination effective as of the date that 
the statute required, rather than the later date on which EPA actually 
made the determination. The Court rejected this view, stating that 
applying it ``would likely impose large costs on states, which would 
face fines and suits for not implementing air pollution prevention 
plans . . . even though they were not on notice at the time.'' Id. at 
68. Similarly, it would be unreasonable to penalize the state of 
Michigan by rejecting its redesignation request for an area that is 
already attaining the 1997 PM2.5 standard and that met all 
applicable requirements known to be in effect at the time of the 
request. For EPA now to reject the redesignation request solely because 
the state did not expressly address subpart 4 requirements of which it 
had no notice, would inflict the same unfairness condemned by the Court 
in Sierra Club v. Whitman.
---------------------------------------------------------------------------

    \2\ Sierra Club v. Whitman was discussed and distinguished in a 
recent D.C. Circuit decision that addressed retroactivity in a quite 
different context, where, unlike the situation here, EPA sought to 
give its regulations retroactive effect. National Petrochemical and 
Refiners Ass'n v. EPA. 630 F.3d 145, 163 (D.C. Cir. 2010), rehearing 
denied 643 F.3d 958 (D.C. Cir. 2011), cert denied 132 S. Ct. 571 
(2011).
---------------------------------------------------------------------------

    ii. Subpart 4 Requirements and Michigan Redesignation Request
    Even if EPA were to take the view that the Court's January 4, 2013, 
decision requires that, in the context of pending redesignations, 
subpart 4 requirements were due and in effect at the time the state 
submitted its redesignation request, EPA proposes to determine that the 
Detroit-Ann Arbor area still qualifies for redesignation to attainment. 
As explained below, EPA believes that the redesignation request for the 
Detroit-Ann Arbor area, though not expressed in terms of subpart 4 
requirements, substantively meets the requirements of that subpart for 
purposes of redesignating the area to attainment.
    With respect to evaluating the relevant substantive requirements of 
subpart 4 for purposes of redesignating the Detroit-Ann Arbor area, EPA 
notes that subpart 4 incorporates components of subpart 1 of part D, 
which contains general air quality planning requirements for areas 
designated as nonattainment. See Section 172(c). Subpart 4, itself, 
contains specific planning and scheduling requirements for 
PM10 \3\ nonattainment areas, and under the Court's January 
4, 2013, decision in NRDC v. EPA, these same statutory requirements 
also apply for PM2.5 nonattainment areas. EPA has 
longstanding general guidance that interprets the 1990 amendments to 
the CAA, making recommendations to states for meeting the statutory 
requirements for SIPs for nonattainment areas. See, ``State 
Implementation Plans; General Preamble for the Implementation of Title 
I of the Clear Air Act Amendments of 1990,'' 57 FR 13498 (April 16, 
1992) (the ``General Preamble''). In the General Preamble, EPA 
discussed the relationship of subpart 1 and subpart 4 SIP requirements, 
and pointed out that subpart 1 requirements were, to an extent, 
``subsumed by, or integrally related to, the more specific PM-10 
requirements.'' 57 FR 13538 (April 16, 1992). The subpart 1 
requirements include, among other things, provisions for attainment 
demonstrations, RACM,

[[Page 39660]]

RFP, emissions inventories, and contingency measures.
---------------------------------------------------------------------------

    \3\ PM10 refers to particulates nominally 10 
micrometers in diameter or smaller.
---------------------------------------------------------------------------

    For the purposes of this redesignation, in order to identify any 
additional requirements which would apply under subpart 4, we are 
considering the Detroit-Ann Arbor area to be a ``moderate'' 
PM2.5 nonattainment area. Under section 188 of the CAA, all 
areas designated nonattainment areas under subpart 4 would initially be 
classified by operation of law as ``moderate'' nonattainment areas, and 
would remain moderate nonattainment areas unless and until EPA 
reclassifies the area as a ``serious'' nonattainment area. Accordingly, 
EPA believes that it is appropriate to limit the evaluation of the 
potential impact of subpart 4 requirements to those that would be 
applicable to moderate nonattainment areas. Section 189(a) and (c) of 
subpart 4 applies to moderate nonattainment areas and includes the 
following: (1) An approved permit program for construction of new and 
modified major stationary sources (section 189(a)(1)(A)); (2) an 
attainment demonstration (section 189(a)(1)(B)); (3) provisions for 
RACM (section 189(a)(1)(C)); and (4) quantitative milestones 
demonstrating RFP toward attainment by the applicable attainment date 
(section 189(c)).
    The permit requirements of subpart 4, as contained in section 
189(a)(1)(A), refer to and apply the subpart 1 permit provisions 
requirements of sections 172 and 173 to PM10, without adding 
to them. Consequently, EPA believes that section 189(a)(1)(A) does not 
itself impose for redesignation purposes any additional requirements 
for moderate areas beyond those contained in subpart 1.\4\ In any 
event, in the context of redesignation, EPA has long relied on the 
interpretation that a fully approved nonattainment new source review 
program is not considered an applicable requirement for redesignation, 
provided the area can maintain the standard with a PSD program after 
redesignation. A detailed rationale for this view is described in a 
memorandum from Mary Nichols, Assistant Administrator for Air and 
Radiation, dated October 14, 1994, entitled, ``Part D New Source Review 
Requirements for Areas Requesting Redesignation to Attainment.'' See 
also rulemakings for Detroit, Michigan (60 FR 12467-12468, March 7, 
1995); Cleveland-Akron-Lorain, Ohio (61 FR 20458, 20469-20470, May 7, 
1996); Louisville, Kentucky (66 FR 53665, October 23, 2001); and Grand 
Rapids, Michigan (61 FR 31834-31837, June 21, 1996).
---------------------------------------------------------------------------

    \4\ The potential effect of section 189(e) on section 
189(a)(1)(A) for purposes of evaluating this redesignation is 
discussed below.
---------------------------------------------------------------------------

    With respect to the specific attainment planning requirements under 
subpart 4,\5\ when EPA evaluates a redesignation request under subpart 
1 and/or 4, any area that is attaining the PM2.5 standard is 
viewed as having satisfied the attainment planning requirements for 
these subparts. For redesignations, EPA has for many years interpreted 
attainment-linked requirements as not applicable for areas attaining 
the standard. In the General Preamble, EPA stated that:
---------------------------------------------------------------------------

    \5\ I.e., attainment demonstration, RFP, RACM, milestone 
requirements, contingency measures.

    The requirements for RFP will not apply in evaluating a request 
for redesignation to attainment since, at a minimum, the air quality 
data for the area must show that the area has already attained. 
Showing that the State will make RFP towards attainment will, 
---------------------------------------------------------------------------
therefore, have no meaning at that point.

    ``General Preamble for the Interpretation of Title I of the CAA 
Amendments of 1990''; (57 FR 13498, 13564, April 16, 1992).

    The General Preamble also explained that [t]he section 172(c)(9) 
requirements are directed at ensuring RFP and attainment by the 
applicable date. These requirements no longer apply when an area has 
attained the standard and is eligible for redesignation. 
Furthermore, section 175A for maintenance plans . . . provides 
specific requirements for contingency measures that effectively 
supersede the requirements of section 172(c)(9) for these areas.

Id.

    EPA similarly stated in its 1992 Calcagni memorandum that, ``[t]he 
requirements for reasonable further progress and other measures needed 
for attainment will not apply for redesignations because they only have 
meaning for areas not attaining the standard.''
    It is evident that, even if we were to consider the Court's January 
4, 2013, decision in NRDC v. EPA to mean that attainment-related 
requirements specific to subpart 4 should be imposed retroactively \6\ 
and thus are now past due, those requirements do not apply to an area 
that is attaining the 1997 and 2006 PM2.5 standard, for the 
purpose of evaluating a pending request to redesignate the area to 
attainment. EPA has consistently enunciated this interpretation of 
applicable requirements under section 107(d)(3)(E) since the General 
Preamble was published more than twenty years ago. Courts have 
recognized the scope of EPA's authority to interpret ``applicable 
requirements'' in the redesignation context. See Sierra Club v. EPA, 
375 F.3d 537 (7th Cir. 2004).
---------------------------------------------------------------------------

    \6\ As EPA has explained above, we do not believe that the 
Court's January 4, 2013 decision should be interpreted so as to 
impose these requirements on the states retroactively. Sierra Club 
v. Whitman, supra.
---------------------------------------------------------------------------

    Moreover, even outside the context of redesignations, EPA has 
viewed the obligation to submit attainment-related SIP planning 
requirements of subpart 4 as inapplicable for areas that EPA determines 
are attaining the standard. EPA's prior ``Clean Data Policy'' 
rulemakings for the PM10 NAAQS, also governed by the 
requirements of subpart 4, explain EPA's reasoning. They describe the 
effects of a determination of attainment on the attainment-related SIP 
planning requirements of subpart 4. See ``Determination of Attainment 
for Coso Junction Nonattainment Area,'' (75 FR 27944, May 19, 2010). 
See also Coso Junction proposed PM10 redesignation, (75 FR 
36023, 36027, June 24, 2010); Proposed and Final Determinations of 
Attainment for San Joaquin Nonattainment Area (71 FR 40952, 40954-55, 
July 19, 2006; and 71 FR 63641, 63643-47 October 30, 2006). In short, 
EPA in this context has also long concluded that to require states to 
meet superfluous SIP planning requirements is not necessary and not 
required by the CAA, so long as those areas continue to attain the 
relevant NAAQS.
    Elsewhere in this notice, EPA proposes to determine that the area 
has attained the 1997 and 2006 PM2.5 standards. Under its 
longstanding interpretation, EPA is proposing to determine here that 
the area meets the attainment-related plan requirements of subparts 1 
and 4.
    Thus, EPA is proposing to conclude that the requirements to submit 
an attainment demonstration under 189(a)(1)(B), a RACM determination 
under sections 172(c)1 and 189(a)(1)(c), a RFP demonstration under 
section 189(c)(1), and contingency measure requirements under section 
172(c)(9) are satisfied for purposes of evaluating the redesignation 
request.
iii. Subpart 4 and Control of PM2.5 Precursors
    The D.C. Circuit in NRDC v. EPA remanded to EPA the two rules at 
issue in the case with instructions to EPA to re-promulgate them 
consistent with the requirements of subpart 4. In this section, EPA 
addresses the Court's opinion with respect to PM2.5 
precursors. While past implementation of subpart 4 for PM10 
has allowed for control of PM10 precursors, such as 
NOX, from major stationary, mobile, and area sources in 
order to attain the standard as expeditiously as practicable, CAA 
section 189(e) specifically provides that

[[Page 39661]]

control requirements for major stationary sources of direct 
PM10 shall also apply to PM10 precursors from 
those sources, except where EPA determines that major stationary 
sources of such precursors ``do not contribute significantly to 
PM10 levels which exceed the standard in the area.''
    EPA's 1997 PM2.5 implementation rule, remanded by the 
D.C. Circuit, contained rebuttable presumptions concerning certain 
PM2.5 precursors applicable to attainment plans and control 
measures related to those plans. Specifically, in 40 CFR 51.1002, EPA 
provided, among other things, that a state was ``not required to 
address VOC [and ammonia] as . . . PM2.5 attainment plan 
precursor[s] and to evaluate sources of VOC [and ammonia] emissions in 
the State for control measures.'' EPA intended these to be rebuttable 
presumptions. EPA established these presumptions at the time because of 
uncertainties regarding the emission inventories for these pollutants 
and the effectiveness of specific control measures in various regions 
of the country in reducing PM2.5 concentrations. EPA also 
left open the possibility for such regulation of VOC and ammonia in 
specific areas where that was necessary.
    The Court in its January 4, 2013 decision made reference to both 
section 189(e) and 40 CFR 51. 1002, and stated that, ``[i]n light of 
our disposition, we need not address the petitioners' challenge to the 
presumptions in [40 CFR 51.1002] that volatile organic compounds and 
ammonia are not PM2.5 precursors, as subpart 4 expressly 
governs precursor presumptions.'' NRDC v. EPA, at 27, n.10.
    Elsewhere in the Court's opinion, however, the Court observed:

[a]mmonia is a precursor to fine particulate matter, making it a 
precursor to both PM2.5 and PM10. For a 
PM10 nonattainment area governed by subpart 4, a 
precursor is presumptively regulated. See 42 U.S.C. Sec.  7513a(e) 
[section 189(e)].

Id. at 21, n.7. For a number of reasons, EPA believes that its proposed 
redesignation of the Detroit-Ann Arbor area is consistent with the 
Court's decision on this aspect of subpart 4. First, while the Court, 
citing section 189(e), stated that ``for a PM10 area 
governed by subpart 4, a precursor is `presumptively regulated,' '' the 
Court expressly declined to decide the specific challenge to EPA's 1997 
PM2.5 implementation rule provisions regarding ammonia and 
VOC as precursors. The Court had no occasion to reach whether and how 
it was substantively necessary to regulate any specific precursor in a 
particular PM2.5 nonattainment area, and did not address 
what might be necessary for purposes of acting upon a redesignation 
request.
    However, even if EPA takes the view that the requirements of 
subpart 4 were deemed applicable at the time the state submitted the 
redesignation request, and disregards the implementation rule's 
rebuttable presumptions regarding ammonia and VOC as PM2.5 
precursors (and any similar provisions reflected in the guidance for 
the 2006 PM2.5 standard), the regulatory consequence would 
be to consider the need for regulation of all precursors from any 
sources in the area to demonstrate attainment and to apply the section 
189(e) provisions to major stationary sources of precursors. In the 
case of Detroit-Ann Arbor, EPA believes that doing so is consistent 
with proposing redesignation of the area for the 1997 PM2.5 
standard. The Detroit-Ann Arbor area has attained both standards 
without any specific additional controls of VOC and ammonia emissions 
from any sources in the area.
    Precursors in subpart 4 are specifically regulated under the 
provisions of section 189(e), which requires, with important 
exceptions, control requirements for major stationary sources of 
PM10 precursors.\7\ Under subpart 1 and EPA's prior 
implementation rule, all major stationary sources of PM2.5 
precursors were subject to regulation, with the exception of ammonia 
and VOC. Thus, we must address here whether additional controls of 
ammonia and VOC from major stationary sources are required under 
section 189(e) of subpart 4 in order to redesignate the area for the 
1997 PM2.5 standard. As explained below, we do not believe 
that any additional controls of ammonia and VOC are required in the 
context of this redesignation.
---------------------------------------------------------------------------

    \7\ Under either subpart 1 or subpart 4, for purposes of 
demonstrating attainment as expeditiously as practicable, a state is 
required to evaluate all economically and technologically feasible 
control measures for direct PM emissions and precursor emissions, 
and adopt those measures that are deemed reasonably available.
---------------------------------------------------------------------------

    In the General Preamble, EPA discusses its approach to implementing 
section 189(e). See 57 FR 13538-13542. With regard to precursor 
regulation under section 189(e), the General Preamble explicitly stated 
that control of VOCs under other Act requirements may suffice to 
relieve a state from the need to adopt precursor controls under section 
189(e) (57 FR 13542). EPA in this proposal proposes to determine that 
Michigan has met the provisions of section 189(e) with respect to 
ammonia and VOCs as precursors. This proposed supplemental 
determination is based on our findings that (1) the Detroit-Ann Arbor 
area contains no major stationary sources of ammonia, and (2) existing 
major stationary sources of VOC are adequately controlled under other 
provisions of the CAA regulating the ozone NAAQS.\8\ In the 
alternative, EPA proposes to determine that, under the express 
exception provisions of section 189(e), and in the context of the 
redesignation of the area, which is attaining the 1997 annual 
PM2.5 standard, at present ammonia and VOC precursors from 
major stationary sources do not contribute significantly to levels 
exceeding the 1997 PM2.5 standard in the Detroit-Ann Arbor 
area. See 57 FR 13539-42.
---------------------------------------------------------------------------

    \8\ The Detroit-Ann Arbor area has reduced VOC emissions through 
the implementation of various SIP approved VOC control programs and 
various on-road and nonroad motor vehicle control programs.
---------------------------------------------------------------------------

    EPA notes that its 1997 PM2.5 implementation rule 
provisions in 40 CFR 51.1002 were not directed at evaluation of 
PM2.5 precursors in the context of redesignation, but at SIP 
plans and control measures required to bring a nonattainment area into 
attainment of the 1997 annual PM2.5 NAAQS. By contrast, 
redesignation to attainment primarily requires the area to have already 
attained due to permanent and enforceable emission reductions, and to 
demonstrate that controls in place can continue to maintain the 
standard. Thus, even if we regard the Court's January 4, 2013, decision 
as calling for ``presumptive regulation'' of ammonia and VOC for 
PM2.5 under the attainment planning provisions of subpart 4, 
those provisions in and of themselves do not require additional 
controls of these precursors for an area that already qualifies for 
redesignation. Nor does EPA believe that requiring Michigan to address 
precursors differently than it has already would result in a 
substantively different outcome.
    Although, as EPA has emphasized, its consideration here of 
precursor requirements under subpart 4 is in the context of a 
redesignation to attainment, EPA's existing interpretation of subpart 4 
requirements with respect to precursors in attainment plans for 
PM10 contemplates that states may develop attainment plans 
that regulate only those precursors that are necessary for purposes of 
attainment in the area in question, i.e., states may determine that 
only certain precursors need be regulated for attainment and control

[[Page 39662]]

purposes.\9\ Courts have upheld this approach to the requirements of 
subpart 4 for PM10.\10\ EPA believes that application of 
this approach to PM2.5 precursors under subpart 4 is 
reasonable. Because the Detroit-Ann Arbor area has already attained the 
1997 annual and 2006 24-hour PM2.5 NAAQS with its current 
approach to regulation of PM2.5 precursors, EPA believes 
that it is reasonable to conclude in the context of this redesignation 
that there is no need to revisit the attainment control strategy with 
respect to the treatment of precursors. Even if the Court's decision is 
construed to impose an obligation to consider additional precursors 
under subpart 4 in evaluating this redesignation request, it would not 
affect EPA's approval here of Michigan's request for redesignation of 
the Detroit-Ann Arbor area. In the context of a redesignation, the area 
has shown that it has attained both standards. Moreover, the state has 
shown, and EPA has proposed to determine, that attainment in this area 
is due to permanent and enforceable emissions reductions on all 
precursors necessary to provide for continued attainment. It follows 
logically that no further control of additional precursors is 
necessary. Accordingly, EPA does not view the January 4, 2013, decision 
of the Court as precluding redesignation of the Detroit-Ann Arbor area 
to attainment for the 1997 PM2.5 NAAQS at this time.
---------------------------------------------------------------------------

    \9\ See, e.g., ``Approval and Promulgation of Implementation 
Plans for California--San Joaquin Valley PM-10 Nonattainment Area; 
Serious Area Plan for Nonattainment of the 24-Hour and Annual PM-10 
Standards,'' 69 FR 30006 (May 26, 2004) (approving a PM10 
attainment plan that impose controls on direct PM10 and 
NOX emissions and did not impose controls on 
SO2, VOC, or ammonia emissions).
    \10\ See, e.g., Assoc. of Irritated Residents v. EPA et al., 423 
F.3d 989 (9th Cir. 2005).
---------------------------------------------------------------------------

    In sum, even if Michigan were required to address precursors for 
the Detroit-Ann Arbor area under subpart 4 rather than under subpart 1, 
as interpreted in EPA's remanded PM2.5 implementation rule, 
EPA would still conclude that the area had met all applicable 
requirements for purposes of redesignation in accordance with section 
107(d)(3(E)(ii) and (v).
b. Michigan Has a Fully Approved Applicable SIP Under Section 110(k) of 
the CAA
    EPA has found that Michigan has a fully approved SIP under section 
110(k) of the CAA for all requirements applicable for purposes of 
redesignation to attainment for the 1997 annual and 2006 24-hour 
PM2.5 standards. EPA may rely on prior SIP approvals in 
approving a redesignation request (See page 3 of the September 4, 1992, 
John Calcagni memorandum; Southwestern Pennsylvania Growth Alliance v. 
Browner, 144 F.3d 984, 989-990 (6th Cir. 1998); Wall v. EPA, 265 F.3d 
426 (6th Cir. 2001)) plus any additional measures it may approve in 
conjunction with a redesignation action. See 68 FR 25413, 25426 (May 
12, 2003). Since the passage of the CAA of 1970, Michigan has adopted 
and submitted, and EPA has fully approved, provisions addressing 
various required SIP elements under particulate matter standards. EPA 
previously approved Michigan's 2005 base year emissions inventory for 
the Detroit-Ann Arbor area as meeting the requirement of section 
172(c)(3) of the CAA for the 1997 annual and 2006 24-hour 
PM2.5 standards.
c. Nonattainment Requirements
    Under section 172, states with nonattainment areas must submit 
plans providing for timely attainment and meeting a variety of other 
requirements. On April 5, 2008, Michigan submitted a state-wide 
attainment demonstration for the 1997 annual standard for 
PM2.5, including the Detroit-Ann Arbor area. However, 
pursuant to 40 CFR 51.1004(c), EPA's determination that the area has 
attained the 1997 annual and the 2006 24-hour PM2.5 
standards suspends the requirement to submit certain planning SIPs 
related to attainment, including attainment demonstration requirements, 
the Reasonably Available Control Technology (RACT)--RACM requirement of 
section 172(c)(1) of the CAA, the RFP and attainment demonstration 
requirements of sections 172(c)(2) and (6) and 182(b)(1) of the CAA, 
and the requirement for contingency measures of section 172(c)(9) of 
the CAA. The attainment demonstration requirement for the 2006 24-hour 
PM2.5 standard has a deadline of December 14, 2012, and, 
therefore, this action relieves Michigan of the requirement to submit 
an attainment demonstration for the 2006 24-hour standard.
    As a result, the only remaining requirement under section 172 to be 
considered is the emissions inventory required under section 172(c)(3). 
As discussed previously, EPA approved the inventory that Michigan 
submitted as part of its attainment plan as satisfying this requirement 
on November 6, 2012 (77 FR 66547). This approval included inventories 
for all four precursors (SO2, NOX, VOCs, and 
ammonia).
    No SIP provisions applicable for redesignation of the Detroit-Ann 
Arbor area are currently disapproved, conditionally approved, or 
partially approved. Michigan has, to date, a fully approved SIP for all 
requirements applicable for purposes of redesignation.

3. The Improvement in Air Quality Is Due to Permanent and Enforceable 
Reductions in Emissions Resulting From Implementation of the SIPs and 
Applicable Federal Air Pollution Control Regulations and Other 
Permanent and Enforceable Reductions (Section 107(d)(3)(E)(iii))

    EPA believes that Michigan has demonstrated that the observed air 
quality improvement in the Detroit-Ann Arbor area is due to permanent 
and enforceable reductions in emissions resulting from implementation 
of the SIPs, Federal measures, and other state-adopted measures.
    In making this demonstration, Michigan has calculated the change in 
emissions between 2005, one of the years used to designate the area as 
nonattainment, and 2008, one of the years the Detroit-Ann Arbor area 
monitored attainment. The reduction in emissions and the corresponding 
improvement in air quality over this time period can be attributed to a 
number of regulatory control measures that the Detroit-Ann Arbor area 
and contributing areas have implemented in recent years.
a. Permanent and Enforceable Controls Implemented
    The following is a discussion of permanent and enforceable measures 
that have been implemented in the area:
i. Federal Emission Control Measures
    Reductions in direct emissions of fine particles and in emissions 
of fine particle precursors have occurred statewide and in upwind areas 
as a result of Federal emission control measures, with additional 
emission reductions expected to occur in the future. Federal emission 
control measures include the following.
    Tier 2 Emission Standards for Vehicles and Gasoline Sulfur 
Standards. These emission control requirements result in lower 
NOX and SO2 emissions from new cars and light 
duty trucks, including sport utility vehicles. Emission standards 
established under EPA's rules became effective between 2004 and 2009. 
The EPA has estimated that, emissions of NOX from new 
vehicles have decreased by the following percentages: Passenger cars 
(light duty vehicles)--77%; light duty trucks, minivans, and sports 
utility vehicles--86%; and, larger sports utility vehicles, vans, and 
heavier trucks--69 to 95%. EPA expects fleet-wide average

[[Page 39663]]

emissions to decline by similar percentages as new vehicles replace 
older vehicles. The Tier 2 standards also reduced the sulfur content of 
gasoline to 30 parts per million (ppm) beginning in January 2006. Most 
gasoline sold in Michigan prior to January 2006 had a sulfur content of 
about 500 ppm.
    Heavy-Duty Diesel Engine Rule. EPA issued this rule in July 2000. 
This rule, which went into effect in 2004, includes standards limiting 
the sulfur content of diesel fuel. A second phase, which took effect in 
2007, reduced fine particle emissions from heavy-duty highway engines 
and further reduced the highway diesel fuel sulfur content to 15 ppm. 
The total program is estimated to have achieved a 90% reduction in 
direct PM2.5 emissions and a 95% reduction in NOX 
emissions for new engines using low sulfur diesel, compared to 
previously existing engines using higher sulfur content diesel. The 
reduction in fuel sulfur content also yielded an immediate reduction in 
sulfate particle emissions from all diesel vehicles.
    Nonroad Diesel Rule. In May 2004, EPA promulgated a new rule for 
large nonroad diesel engines, such as those used in construction, 
agriculture, and mining equipment, to be phased in between 2008 and 
2014. The rule reduces the sulfur content in nonroad diesel fuel by 
over 99%. Prior to 2006, nonroad diesel fuel averaged approximately 
3,400 ppm sulfur. This rule limited nonroad diesel sulfur content to 
500 ppm by 2006, with a further reduction to 15 ppm by 2010. The 
combined engine and fuel rules will reduce NOX and PM 
emissions from large nonroad diesel engines by over 90%, compared to 
nonroad engines using higher sulfur content diesel. It is estimated 
that compliance with this rule will cut NOX emissions from 
nonroad diesel engines by up to 90%. This rule achieved some emission 
reductions by 2008 and was fully implemented by 2010. The reduction in 
fuel sulfur content also yielded an immediate reduction in sulfate 
particle emissions from all diesel vehicles.
    Nonroad Large Spark-Ignition Engine and Recreational Engine 
Standards. In November 2002, EPA promulgated emission standards for 
groups of previously unregulated nonroad engines. These engines include 
large spark-ignition engines such as those used in forklifts and 
airport ground-service equipment; recreational vehicles using spark-
ignition engines such as off-highway motorcycles, all-terrain vehicles, 
and snowmobiles; and recreational marine diesel engines. Emission 
standards from large spark-ignition engines were implemented in two 
tiers, with Tier 1 starting in 2004 and Tier 2 in 2007. Recreational 
vehicle emission standards were phased in between 2006 and 2012. Marine 
Diesel engine standards were phased in from 2006 through 2009. With 
full implementation of the entire nonroad spark-ignition engine and 
recreational engine standards, EPA expects an 80% reduction in 
NOX emissions by 2020. Some of these emission reductions 
occurred by the 2008-2010 period used to demonstrate attainment, and 
additional emission reductions will occur during the maintenance 
period.
ii. Control Measures in Contributing Areas
    Given the significance of sulfates and nitrates in the Detroit-Ann 
Arbor area, the area's air quality is strongly affected by regulated 
emissions from power plants.
    NOX SIP Call. On October 27, 1998 (63 FR 57356), EPA issued a 
NOX SIP Call requiring the District of Columbia and 22 
states to reduce emissions of NOX. Affected states were 
required to comply with Phase I of the SIP Call beginning in 2004, and 
Phase II beginning in 2007. Emission reductions resulting from 
regulations developed in response to the NOX SIP Call are 
permanent and enforceable.
    CAIR. On May 12, 2005, EPA promulgated CAIR, which requires 
significant reductions in emissions of SO2 and 
NOX from electric generating units to limit the interstate 
transport of these pollutants and the ozone and fine particulate matter 
they form in the atmosphere. See 76 FR 70093. The Court initially 
vacated CAIR, North Carolina v. EPA, 531 F.3d 896 (D.C. Cir. 2008), but 
ultimately remanded the rule to EPA without vacatur to preserve the 
environmental benefits provided by CAIR, North Carolina v. EPA, 550 
F.3d 1176, 1178 (D.C. Cir. 2008). In response to the court's decision, 
EPA promulgated CSAPR to address interstate transport of NOX 
and SO2 in the eastern United States. See 76 FR 48208 
(August 8, 2011).
    On December 30, 2011, the D.C. Circuit issued an order addressing 
the status of CSAPR and CAIR in response to motions filed by numerous 
parties seeking a stay of CSAPR pending judicial review. In that order, 
the Court stayed CSAPR pending resolution of the petitions for review 
of that rule. The Court also indicated that EPA was expected to 
continue to administer CAIR in the interim until judicial review of 
CSAPR was completed.
    On August 21, 2012, the D.C. Circuit issued a decision to vacate 
CSAPR. In that decision, it also ordered EPA to continue administering 
CAIR ``pending the promulgation of a valid replacement.'' EME Homer 
City, 696 F.3d at 38. The D.C. Circuit denied all petitions for 
rehearing on January 24, 2013. EPA and other parties have filed 
petitions for certiorari to the U.S. Supreme Court, but those petitions 
have not been acted on to date.
    In light of these unique circumstances and for the reasons 
explained below, to the extent that attainment is due to emission 
reductions associated with CAIR, EPA is here proposing to determine 
that those reductions are sufficiently permanent and enforceable for 
purposes of CAA sections 107(d)(3)(E)(iii) and 175A. EPA therefore 
proposes to approve the redesignation request and the related SIP 
revision for Livingston, Macomb, Monroe, Oakland, St. Clair, Washtenaw, 
and Wayne Counties in Michigan, including Michigan's plan for 
maintaining attainment of the PM2.5 standard in the Detroit-
Ann Arbor area.
    As directed by the D.C. Circuit, CAIR remains in place and 
enforceable until substituted by a valid replacement rule. Michigan's 
SIP revision, which lists CAIR as a control measure, was approved by 
EPA on December 20, 2007 (72 FR 72256), for the purpose of reducing 
SO2 and NOX emissions. CAIR was thus in place and 
getting emission reductions when the Detroit-Ann Arbor began monitoring 
attainment of the 1997 annual and 2006 24-hour NAAQS. The quality-
assured, certified monitoring data used to demonstrate the area's 
attainment of the 1997 annual PM2.5 NAAQS by the April 2010 
attainment deadline was also impacted by CAIR.
    To the extent that the Detroit-Ann Arbor area relies on CAIR to 
maintain the standards, the recent directive from the D.C. Circuit in 
EME Homer City ensures that the reductions associated with CAIR will be 
permanent and enforceable for the necessary time period. EPA has been 
ordered by the Court to develop a new rule to address interstate 
transport to replace CSAPR and the opinion makes clear that after 
promulgating that new rule EPA must provide states an opportunity to 
draft and submit SIPs to implement that rule. Thus, CAIR will remain in 
place until EPA has promulgated a final rule through a notice-and-
comment rulemaking process, states have had an opportunity to draft and 
submit SIPs, EPA has reviewed the SIPs to determine if they can be 
approved, and EPA has taken action on the SIPs, including promulgating 
a FIP if appropriate. The Court's clear instruction to EPA that it must 
continue to administer CAIR until a valid replacement exists provides 
an

[[Page 39664]]

additional backstop: By definition, any rule that replaces CAIR and 
meets the Court's direction would require upwind states to have SIPs 
that eliminate significant contributions to downwind nonattainment and 
prevent interference with maintenance in downwind areas.
    Further, in vacating CSAPR and requiring EPA to continue 
administering CAIR, the D.C. Circuit emphasized that the consequences 
of vacating CAIR ``might be more severe now in light of the reliance 
interests accumulated over the intervening four years.'' EME Homer 
City, 696 F.3d at 38. The accumulated reliance interests include the 
interests of states that reasonably assumed they could rely on 
reductions associated with CAIR which brought certain nonattainment 
areas into attainment with the NAAQS. If EPA were prevented from 
relying on reductions associated with CAIR in redesignation actions, 
states would be forced to impose additional, redundant reductions on 
top of those achieved by CAIR. EPA believes this is precisely the type 
of irrational result the Court sought to avoid by ordering EPA to 
continue administering CAIR. For these reasons, EPA believes it is 
appropriate to allow states to rely on CAIR, and the existing emissions 
reductions achieved by CAIR, as sufficiently permanent and enforceable 
for purposes such as redesignation. Following promulgation of the 
replacement rule, EPA will review SIPs as appropriate to identify 
whether there are any issues that need to be addressed.
iii. Consent Decrees and Permanent Shutdowns
    Michigan has also submitted multiple permanent and enforceable 
measures to address PM2.5 and precursors at single sources, 
by retiring credits from permits once an emissions source has shut 
down. A discussion of single source shutdowns and their emissions are 
found in the Appendix to Michigan's submission. These single site 
emission reductions include multiple facility shutdowns, which have 
resulted in the retirement of permitted emission credits, including the 
following facilities: Ajax Materials Corporation, Edison Energy 
Services, Great Lakes Petroleum Terminal, LLC, and M-Lok Incorporated. 
These facility shutdowns resulted in an estimated reduction of over 100 
tpy of NOX and over 4 tpy of direct PM2.5. 
Michigan has also attributed emission reductions to various permanent 
and enforceable controls required at multiple point source facilities 
in the Detroit-Ann Arbor area. Controls required on facilities through 
permanent and Federally enforceable construction permits and consent 
orders through enforcement actions include: Baghouse controls on 
several blast furnace operations the basic oxygen furnace at Severstal 
steel mill (permit 182-05B) and baghouse upgrades on blast 
furnaces at US Steel (Consent Order 1-2005).
b. Emission Reductions
    Michigan developed an emissions inventory for NOX, 
direct PM2.5, and SO2 for 2005, one of the years 
used to designate the area as nonattainment, and 2008, one of the years 
the Detroit-Ann Arbor area monitored attainment of the standard. EPA 
previously approved the emissions inventory for the 2005 base year on 
November 6, 2012 (77 FR 66547).
    Emissions of SO2 and NOX from electric 
generating units (EGUs) were derived from EPA's Clean Air Market's acid 
rain database. These emissions reflect Michigan NOX emission 
budgets resulting from EPA's NOX SIP call. All other point 
source emissions were obtained from Michigan's source facility 
emissions reporting.
    Area source emissions the Detroit-Ann Arbor area for 2005 were 
taken from periodic emissions inventories.\11\ These 2005 area source 
emission estimates were extrapolated to 2008. Source growth factors 
were supplied by the Lake Michigan Air Directors Consortium (LADCO).
---------------------------------------------------------------------------

    \11\ Periodic emission inventories are derived by states every 
three years and reported to the EPA. These periodic emission 
inventories are required by the Federal Consolidated Emissions 
Reporting Rule, codified at 40 CFR Subpart A. EPA revised these and 
other emission reporting requirements in a final rule published on 
December 17, 2008, at 73 FR 76539.
---------------------------------------------------------------------------

    Nonroad mobile source emissions were extrapolated from nonroad 
mobile source emissions reported in EPA's 2005 National Emissions 
Inventory (NEI). Contractors were employed by LADCO to estimate 
emissions for commercial marine vessels and railroads.
    On-road mobile source emissions were calculated using EPA's mobile 
source emission factor model, MOVES2010a, in conjunction with 
transportation model results developed by local Metropolitan Planning 
Organization SEMCOG.
    All emissions estimates discussed below were documented in the 
submittals and appendices to Michigan's redesignation request submittal 
of July 5, 2011. For these data and additional emissions inventory 
data, the reader is referred to EPA's digital docket for this rule, 
http://www.regulations.gov, for docket number EPA-R05-OAR-2011-0673, 
which includes a digital copy of Michigan's submittal.
    Emissions data in tons per year (tpy) for the Detroit-Ann Arbor 
area are shown in Tables 2, 3, and 4 below.

 Table 2--Comparison of 2005 Emissions From the Nonattainment Year and 2008 Emissions for an Attainment Year for
                                     NOX in the Detroit-Ann Arbor Area (tpy)
----------------------------------------------------------------------------------------------------------------
                                                                                                   Net change
                                                                  2005              2008           (2005-2008)
----------------------------------------------------------------------------------------------------------------
Point (EGU)...............................................         69,756.71         70,008.00            251.29
Non-EGU...................................................         18,684.20         18,817.18            132.98
Area......................................................         15,949.67         17,157.57          1,207.90
Nonroad...................................................         28,829.50         24,065.61         -4,763.89
Marine, Air, and Rail.....................................          7,380.89          6,380.17         -1,000.72
On-road...................................................        154,294.00        119,194.00        -35,100.00
                                                           -----------------------------------------------------
    Total.................................................        294,894.98        255,622.53        -39,272.45
----------------------------------------------------------------------------------------------------------------

[[Page 39665]]

 Table 3--Comparison of 2005 Emissions From the Nonattainment Year and 2008 Emissions for an Attainment Year for
                                     SO2 in the Detroit-Ann Arbor Area (tpy)
----------------------------------------------------------------------------------------------------------------
                                                                                                Net change (2005-
                                                                  2005              2008              2008)
----------------------------------------------------------------------------------------------------------------
Point (EGU)...............................................        227,751.98        233,870.64          6,118.66
Non-EGU...................................................         16,240.13         19,793.49          3,553.36
Area......................................................          4,629.99          5,702.94          1,072.95
Nonroad...................................................          2,739.34            426.61         -2,312.73
Marine, Air, and Rail.....................................            681.42            588.82            -92.60
On-road...................................................          3,809.00          1,066.00         -2,743.00
                                                           -----------------------------------------------------
    Total.................................................        255,851.86        261,448.50          5,596.64
----------------------------------------------------------------------------------------------------------------

 Table 4--Comparison of 2005 Emissions From the Nonattainment Year and 2008 Emissions for an Attainment Year for
                                direct PM2.5 in the Detroit-Ann Arbor Area (tpy)
----------------------------------------------------------------------------------------------------------------
                                                                                                Net change (2005-
                                                                  2005              2008              2008)
----------------------------------------------------------------------------------------------------------------
Point (EGU)...............................................          1,105.51          1,375.31            269.80
Non-EGU...................................................          2,454.95          1,605.72           -849.23
Area......................................................          5,456.25          5,406.06            -50.19
Nonroad...................................................          2,203.67          1,773.31           -430.36
MAR.......................................................            193.09            165.62            -27.47
On-road...................................................          5,323.00          4,360.00           -963.00
                                                           -----------------------------------------------------
    Total.................................................         16,736.47         14,686.02         -2,050.45
----------------------------------------------------------------------------------------------------------------

    Table 2 and 4 show reductions in both NOX and direct 
PM2.5 emissions for the Detroit-Ann Arbor area by 39,272.45 
tpy for NOX, and 2,050.45 tpy for direct PM2.5 
between 2005, a nonattainment year and 2008, an attainment year.
    Although Table 3 shows an increase in SO2 emissions of 
5,596.64 tpy, the state submission includes sufficient evidence to show 
that, even with the increase in SO2, the area has reached 
attainment of the 1997 annual and 2006 24-hour PM2.5 NAAQS 
and will continue to maintain that designation into the future due to 
multiple actions by the state. The evidence submitted by the state 
contains modeling, monitoring, and trend analysis. Based on monitoring 
data, the trend analysis for the area shows a steady decline in 
PM2.5 emissions, with a significant drop in concentrations 
beginning in 2006. Since meteorology can play a large part in 
dispersion of PM2.5, which can greatly affect monitored 
concentrations, LADCO and the state have normalized the data to remove 
meteorological effects using a statistical analysis, and the state has 
shown in its submission that the concentrations observed are due to 
real reductions in PM2.5 and its precursors, not just 
meteorological effects.
    The state has also submitted monitored data showing 
PM2.5 composition. PM2.5 can be classified by its 
chemical composition, allowing the state and EPA to discern what 
percentage each major precursor contributes to PM2.5 
concentrations in the Detroit-Ann Arbor area. PM2.5 
composition attributed to SO2 is, on average, 20-30% of 
total PM2.5 monitored concentrations, so, although 
SO2 emissions have increased, NOX and 
PM2.5 emissions (which contribute 60-75% of the total 
PM2.5 monitored concentrations, and are both significant 
contributors under EPA guidance) have each been reduced by more than 
10%, and PM2.5 emissions have declined.
    Based on the information summarized above, Michigan has adequately 
demonstrated that the improvement in air quality is due to permanent 
and enforceable emissions reductions.

4. Michigan Has a Fully Approved Maintenance Plan Pursuant to Section 
175A of the CAA (Section 107(d)(3)(E)(iv))

    In conjunction with Michigan's request to redesignate the Detroit-
Ann Arbor nonattainment area to attainment status, Michigan has 
submitted a SIP revision to provide for maintenance of the 1997 annual 
and 2006 24-hour PM2.5 NAAQS in the area through 2022.
a. What is required in a maintenance plan?
    Section 175A of the CAA sets forth the required elements of a 
maintenance plan for areas seeking redesignation from nonattainment to 
attainment. Under section 175A, the plan must demonstrate continued 
attainment of the applicable NAAQS for at least ten years after EPA 
approves a redesignation to attainment. Eight years after 
redesignation, the state must submit a revised maintenance plan which 
demonstrates that attainment will continue to be maintained for ten 
years following the initial ten year maintenance period. To address the 
possibility of future NAAQS violations, the maintenance plan must 
contain contingency measures with a schedule for implementation as EPA 
deems necessary to assure prompt correction of any future 
PM2.5 violations.
    The September 4, 1992, Calcagni memorandum provides additional 
guidance on the content of a maintenance plan. The memorandum states 
that a maintenance plan should address the following items: The 
attainment emissions inventory, a maintenance demonstration showing 
maintenance for the ten years of the maintenance period, a commitment 
to maintain the existing monitoring network, factors and procedures to 
be used for verification of continued attainment of the NAAQS, and a 
contingency plan to prevent or correct future violations of the NAAQS.
    Section 175A requires a state seeking redesignation to attainment 
to submit a SIP revision to provide for the maintenance of the NAAQS in 
the area ``for at least 10 years after the redesignation.'' EPA has 
interpreted this as a showing of maintenance ``for a period of ten 
years following redesignation.'' Calcagni memorandum,

[[Page 39666]]

p. 9. Where the emissions inventory method of showing maintenance is 
used, its purpose is to show that emissions during the maintenance 
period will not increase over the attainment year inventory. Calcagni 
Memorandum, pp. 9-10.
    As discussed in detail in the section below, the state's 
maintenance plan submission expressly documents that the area's 
emissions inventories will remain below the attainment year inventories 
through 2022. In addition, for the reasons set forth below, EPA 
believes that the state's submission, in conjunction with additional 
supporting information, further demonstrates that the area will 
continue to maintain the 1997 annual and 2006 24-hour NAAQS at least 
through 2023. Thus, any EPA action to finalize its proposed approval of 
the redesignation request and maintenance plans in 2013, will be based 
on a showing, in accordance with section 175A, that the state's 
maintenance plan provides for maintenance for at least ten years after 
redesignation.
b. Attainment Inventory
    Michigan developed an emissions inventory for NOX, 
direct PM2.5, and SO2 for 2008, one of the years 
in the period during which the Detroit-Ann Arbor area monitored 
attainment of the 1997 annual PM2.5 standard, as described 
previously. The attainment level of emissions is summarized in Tables 
2, 3, and 4, above.
c. Demonstration of Maintenance
    Along with the redesignation request, Michigan submitted a revision 
to its PM2.5 SIP to include a maintenance plan for the 
Detroit-Ann Arbor area, as required by section 175A of the CAA. 
Michigan's plan demonstrates maintenance of the 1997 annual and 2006 
24-hour PM2.5 standard through 2022 by showing that current 
and future emissions of NOX, directly emitted 
PM2.5 and SO2 in the area remain at or below 
attainment year emission levels. Section 175A requires a state seeking 
redesignation to attainment to submit a SIP revision to provide for the 
maintenance of the NAAQS in the area ``for at least 10 years after the 
redesignation.'' EPA has interpreted this as a showing of maintenance 
``for a period of ten years following redesignation.'' Calcagni 
memorandum, p. 9. Where the emissions inventory method of showing 
maintenance is used, its purpose is to show that emissions during the 
maintenance period will not increase over the attainment year 
inventory. Calcagni Memorandum, pp. 9-10.
    As discussed in detail in the section below, the state's 
maintenance plan submission expressly documents that the area's 
emissions inventories will remain below the attainment year inventories 
through 2022. In addition, for the reasons set forth below, EPA 
believes that the state's submission, in conjunction with additional 
supporting information, further demonstrates that the area will 
continue to maintain the PM2.5 standard at least through 
2023. Thus, if EPA finalizes its proposed approval of the redesignation 
request and maintenance plans in 2013, it will be based on a showing, 
in accordance with section 175A, that the state's maintenance plan 
provides for maintenance for at least ten years after redesignation.
    Michigan's plan demonstrates maintenance of the 1997 annual and 
2006 24-hour PM2.5 NAAQS through 2022 by showing that 
current and future emissions of NOX, directly emitted 
PM2.5 and SO2 for the area remain at or below 
attainment year emission levels.
    The rate of decline in emissions of PM2.5, 
NOX, and SO2 from the attainment year 2008 
through 2022 indicates that emissions inventory levels not only 
significantly decline between 2008 and 2022, but that the reductions 
will continue in 2023 and beyond. The average annual rate of decline is 
1,367 tpy for SO2, 8,495 tpy of NOX, and 264 tpy 
of direct PM. These rates of decline are consistent with monitored and 
projected air quality trends, emissions reductions achieved through 
emissions controls and regulations that will remain in place beyond 
2023 and through fleet turnover that will continue beyond 2023, among 
other factors. We are proposing to find the mobile source contribution 
to these emissions is expected to remain insignificant in 2023 and 
beyond because of fleet turnover in upcoming years that will result in 
cleaner vehicles and cleaner fuels.
    A maintenance demonstration need not be based on modeling. See Wall 
v. EPA, 265 F.3d 426 (6th Cir. 2001), Sierra Club v. EPA, 375 F.3d 537 
(7th Cir. 2004). See also 66 FR 53094, 53099-53100 (October 19, 2001), 
68 FR 25413, 25430-25432 (May 12, 2003). Michigan uses emissions 
inventory projections for the years 2018 and 2022 to demonstrate 
maintenance for the entire Detroit-Ann Arbor area. The projected 
emissions were estimated by Michigan, with assistance from LADCO and 
SEMCOG, who used the MOVES2010a model for mobile source projections. 
Projection modeling of inventory emissions was done for the 2018 
interim year emissions using estimates based on the 2009 and 2018 LADCO 
modeling inventory, using LADCO's growth factors, for all sectors. The 
2022 maintenance year emission estimates were based on emissions 
estimates from the 2018 LADCO modeling. Table 5 shows the 2008 
attainment base year emission estimates and the 2018 and 2022 emission 
projections for the Detroit-Ann Arbor area, taken from Michigan's July 
5, 2011, submission.

 Table 5--Comparison of 2008, 2018 and 2022 NOX, Direct PM2.5, and SO2 Emission Totals (tpy) for the Detroit-Ann
                                                   Arbor Area
----------------------------------------------------------------------------------------------------------------
                                                                   SO2               NOX              PM2.5
----------------------------------------------------------------------------------------------------------------
2008 (baseline)...........................................        261,447.50        255,622.53         14,686.02
2018......................................................        231,218.01        146,017.66         11,363.91
2022......................................................        242,301.62        136,679.11         10,976.30
Net Change (2008-2022)....................................        -19,145.88       -118,943.42         -3,709.72
                                                                 8% decrease      47% decrease      26% decrease
----------------------------------------------------------------------------------------------------------------

    Table 5 shows that, for the period between 2008 and the maintenance 
projection for 2022, the Detroit-Ann Arbor area will reduce 
NOX emissions by 118,943.42 tpy; direct PM2.5 
emissions by 3,709.72 tpy; and SO2 emissions by 19,145.88 
tpy. The 2022 projected emissions levels are significantly below 
attainment year inventory levels, and, based on the rate of decline, it 
is highly improbable that any increases in these levels will occur in 
2023 and beyond. Thus, the emissions inventories set forth in Table 5 
show that the area will continue to maintain the annual and 24-hour 
PM2.5 standards during the maintenance period and at least 
through 2023.

[[Page 39667]]

    As Table 1 demonstrates, monitored PM2.5 design value 
concentrations in Detroit-Ann Arbor are well below the NAAQS in the 
years beyond 2008, an attainment year for the area. Further, those 
values are trending downward as time progresses. Based on the future 
projections of emissions in 2015 and 2022 showing significant emissions 
reductions in direct PM2.5, NOX, and 
SO2, it is very unlikely that monitored PM2.5 
values in 2023 and beyond will show violations of the NAAQS. 
Additionally, the 2009-2011 design values of 11.6 and 32 [mu]g/m\3\ 
(annual and 24-hour, respectively) provide a sufficient margin in the 
unlikely event emissions rise slightly in the future.

Maintenance Plan Evaluation of Ammonia and VOCs

    With regard to the redesignation of the Detroit-Ann Arbor area, in 
evaluating the effect of the Court's remand of EPA's implementation 
rule, which included presumptions against consideration of VOC and 
ammonia as PM2.5 precursors, EPA in this proposal is also 
considering the impact of the decision on the maintenance plan required 
under sections 175A and 107(d)(3)(E)(iv). To begin with, EPA notes that 
the area has attained the 1997 and 2006 PM2.5 standards and 
that the state has shown that attainment of those standards is due to 
permanent and enforceable emission reductions.
    EPA proposes to determine that the state's maintenance plan shows 
continued maintenance of the standards by tracking the levels of the 
precursors whose control brought about attainment of the 1997 and 2006 
PM2.5 standard in the Detroit-Ann Arbor area. EPA therefore 
believes that the only additional consideration related to the 
maintenance plan requirements that results from the Court's January 4, 
2013, decision is that of assessing the potential role of VOC and 
ammonia in demonstrating continued maintenance in this area. As 
explained below, based upon documentation provided by the state and 
supporting information, EPA believes that the maintenance plan for the 
Detroit-Ann Arbor area need not include any additional emission 
reductions of VOC or ammonia in order to provide for continued 
maintenance of the standard.
    First, as noted above in EPA's discussion of section 189(e), VOC 
emission levels in this area have historically been well-controlled 
under SIP requirements related to ozone and other pollutants. Second, 
total ammonia emissions throughout the Detroit-Ann Arbor area are very 
low, estimated to be less than 7,000 tpy. See Table 6 below. This 
amount of ammonia emissions appears especially small in comparison to 
the total amounts of SO2, NOX, and even direct 
PM2.5 emissions from sources in the area. Third, as 
described below, available information shows that no precursor, 
including VOC and ammonia, is expected to increase over the maintenance 
period so as to interfere with or undermine the state's maintenance 
demonstration.
    Michigan's maintenance plan shows that emissions of direct 
PM2.5, SO2, and NOX are projected to 
decrease by 3,709.72 tpy, 19,145.88 tpy, and 118,943.42 tpy, 
respectively, over the maintenance period. See Table 5 above. In 
addition, emissions inventories used in the regulatory impact analysis 
(RIA) for the 2012 PM2.5 NAAQS show that VOC and ammonia 
emissions are projected to decrease by 61,993 tpy and 577 tpy, 
respectively between 2007 and 2020. See Table 6 below. While the RIA 
emissions inventories are only projected out to 2020, there is no 
reason to believe that this downward trend would not continue through 
2022. Given that the Detroit-Ann Arbor area is already attaining the 
1997 annual and 2006 24-hour PM2.5 NAAQS even with the 
current level of emissions from sources in the area, the downward trend 
of emissions inventories would be consistent with continued attainment. 
Indeed, projected emissions reductions for the precursors that the 
state is addressing for purposes of the 1997 PM2.5 NAAQS 
indicate that the area should continue to attain the NAAQS following 
the precursor control strategy that the state has already elected to 
pursue. Even if VOC and ammonia emissions were to increase unexpectedly 
between 2020 and 2022, the overall emissions reductions projected in 
direct PM2.5, SO2, and NOX would be 
sufficient to offset any increases. For these reasons, EPA believes 
that local emissions of all of the potential PM2.5 
precursors will not increase to the extent that they will cause 
monitored PM2.5 levels to violate the 1997 or the 2006 
PM2.5 standard during the maintenance period.

             Table 6--Comparison of 2007 and 2020 VOC and Ammonia Emission Totals by Source Sector (tpy) for the Detroit-Ann Arbor Area \12\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                VOC                                           Ammonia
                                                         -----------------------------------------------------------------------------------------------
                         Sector                                                             Net change                                      Net change
                                                               2007            2020          2007-2020         2007            2020          2007-2020
--------------------------------------------------------------------------------------------------------------------------------------------------------
Point...................................................          15,250          15,324              73             210             566             356
Area....................................................          64,265          60,714          -3,552           4,531           4,627              96
Nonroad.................................................          25,717          13,823         -11,894              28              35               6
On-road.................................................          67,242          20,682         -46,561           2,119           1,104          -1,015
Fires...................................................             124             124               0             344             349               6
                                                         -----------------------------------------------------------------------------------------------
    Total...............................................         172,599         110,666         -61,933           6,897           6,341            -557
--------------------------------------------------------------------------------------------------------------------------------------------------------

     
    In addition, available air quality modeling analyses show continued 
maintenance of the standard during the maintenance period. The current 
air quality annual and 24-hour design values for the area are 11.6 and 
32 [micro]g/m\3\ (based on 2009-11 air quality data), which are well 
below the 1997 annual and 2006 24-hour PM2.5 NAAQS of 15 and 
35 [micro]g/m\3\. Moreover, the modeling analysis conducted for the RIA 
for the 2012 PM2.5 NAAQS indicates that the design values 
for this area are expected to continue to decline through 2020. In the 
RIA analysis, the highest 2020 modeled design value for the Detroit-Ann 
Arbor area is 11.6 [micro]g/m\3\. Given that precursor emissions are 
projected to decrease through 2022, it is reasonable to conclude that 
monitored PM2.5 levels in this area will also continue to 
decrease through 2022.
---------------------------------------------------------------------------

    \12\ These emissions estimates were taken from the emissions 
inventories developed for the RIA for the 2012 PM2.5 
NAAQS which can be found in the docket.
---------------------------------------------------------------------------

    Thus, EPA believes that there is ample justification to conclude 
that the Detroit-Ann Arbor area should be

[[Page 39668]]

redesignated, even taking into consideration the emissions of other 
precursors potentially relevant to PM2.5. After 
consideration of the D.C. Circuit's January 4, 2013 decision, and for 
the reasons set forth in this notice, EPA proposes to approve the 
state's maintenance plan and its request to redesignate the Detroit-Ann 
Arbor area to attainment for the PM2.5 1997 annual and 2006 
24-hour NAAQS.
    Based on the information summarized above, Michigan has adequately 
demonstrated maintenance of both PM2.5 standards in this 
area for a period extending in excess of ten years from expected final 
action on Michigan's redesignation request.
d. Monitoring Network
    Michigan's maintenance plan includes additional elements. 
Michigan's plan includes a commitment to continue to operate its EPA-
approved monitoring network, as necessary to demonstrate ongoing 
compliance with the NAAQS. Michigan currently operates 14 
PM2.5 monitors in the Detroit-Ann Arbor Michigan.
e. Verification of Continued Attainment
    Michigan remains obligated to continue to quality-assure monitoring 
data and enter all data into the AQS in accordance with Federal 
guidelines. Michigan will use these data, supplemented with additional 
information as necessary, to assure that the area continues to attain 
the standard. Michigan will also continue to develop and submit 
periodic emission inventories as required by the Federal Consolidated 
Emissions Reporting Rule (67 FR 39602, June 10, 2002) to track future 
levels of emissions. Both of these actions will help to verify 
continued attainment in accordance with 40 CFR part 58.
f. Contingency Plan
    The contingency plan provisions are designed to promptly correct or 
prevent a violation of the NAAQS that might occur after redesignation 
of an area to attainment. Section 175A of the CAA requires that a 
maintenance plan include such contingency measures as EPA deems 
necessary to assure that the state will promptly correct a violation of 
the NAAQS that occurs after redesignation. The maintenance plan should 
identify the contingency measures to be adopted, a schedule and 
procedure for adoption and implementation of the contingency measures, 
and a time limit for action by the state. The state should also 
identify specific indicators to be used to determine when the 
contingency measures need to be adopted and implemented. The 
maintenance plan must include a requirement that the state will 
implement all pollution control measures that were contained in the SIP 
before redesignation of the area to attainment. See section 175A(d) of 
the CAA.
    Michigan's contingency plan defines an Action Level Response. The 
Action Level Response will be prompted by standard two-year annual 
average of 15 [mu]g/m\3\ or higher (annual standard) and a two-year 
98th percentile average monitored value of 35 [mu]g/m\3\ or higher (24-
hour standard) within the maintenance area. If an Action Level Response 
is triggered, Michigan will adopt and implement appropriate control 
measures within 18 months from the end of the year in which monitored 
air quality triggering a response occurs.
    Michigan's candidate contingency measures include the following:
    i. Wood stove change-out program;
    ii. Steel mill controls;
    iii. Coke battery controls;
    iv. Diesel retrofit program;
    v. Reduced idling program;
    vi. ICI boiler controls;
    vii. Food preparation flame broiler control and;
    viii. EGU controls.
    Michigan further commits to conduct ongoing review of its data, and 
if monitored concentrations or emissions are trending upward, Michigan 
commits to take appropriate steps to avoid a violation if possible. 
Michigan commits to continue implementing SIP requirements upon and 
after redesignation. EPA believes that Michigan's contingency measures, 
as well as the commitment to continue implementing any SIP 
requirements, satisfy the pertinent requirements of section 175A(d).
    As required by section 175A(b) of the CAA, Michigan commits to 
submit to the EPA an updated PM2.5 maintenance plan eight 
years after redesignation of the Detroit-Ann Arbor area to cover an 
additional ten year period beyond the initial ten year maintenance 
period. As required by section 175A of the CAA, Michigan has also 
committed to retain the PM2.5 control measures contained in 
the SIP prior to redesignation.
    For all of the reasons set forth above, EPA is proposing to approve 
Michigan's 1997 annual and 2006 24-hour PM2.5 maintenance 
plan for the Detroit-Ann Arbor area as meeting the requirements of CAA 
section 175A.

5. Motor Vehicle Emissions Budget (MVEBs) for the Mobile Source 
Contribution to PM2.5 and NOX

a. How are MVEBs developed and what are the MVEBs for the Detroit-Ann 
Arbor area?
    Under the CAA, states are required to submit, at various times, 
control strategy SIP revisions and maintenance plans for 
PM2.5 nonattainment areas and for areas seeking 
redesignation to attainment of the PM2.5 standards. These 
emission control strategy SIP revisions (e.g., RFP and attainment 
demonstration SIP revisions) and maintenance plans create MVEBs based 
on on-road mobile source emissions for criteria pollutants and/or their 
precursors to address pollution from on-road transportation sources. 
The MVEBs are the portions of the total allowable emissions that are 
allocated to highway and transit vehicle use that, together with 
emissions from other sources in the area, will provide for attainment, 
RFP, or maintenance, as applicable.
    Under 40 CFR part 93, a MVEB for an area seeking a redesignation to 
attainment is established for the last year of the maintenance plan and 
could also be established for an interim year or years. The MVEB serves 
as a ceiling on emissions from an area's planned transportation system. 
The MVEB concept is further explained in the preamble to the November 
24, 1993, transportation conformity rule (58 FR 62188).
    Under section 176(c) of the CAA, new transportation plans and 
transportation improvement programs (TIPs) must be evaluated to 
determine if they conform to the purpose of the area's SIP. Conformity 
to the SIP means that transportation activities will not cause new air 
quality violations, worsen existing air quality violations, or delay 
timely attainment of the NAAQS or any required interim milestone. If a 
transportation plan or TIP does not conform, most new transportation 
projects that would expand the capacity of roadways cannot go forward. 
Regulations at 40 CFR part 93 set forth EPA policy, criteria, and 
procedures for demonstrating and assuring conformity of such 
transportation activities to a SIP.
    When reviewing SIP revisions containing MVEBs, including attainment 
strategies, rate-of-progress plans, and maintenance plans, EPA must 
affirmatively find adequate and/or approve the MVEBs for use in 
determining transportation conformity before the MVEBs can be used. 
Once EPA affirmatively approves and/or finds the submitted MVEBs to be 
adequate for transportation conformity purposes, the

[[Page 39669]]

MVEBs must be used by state and Federal agencies in determining whether 
proposed transportation plans and TIPs conform to the SIP as required 
by section 176(c) of the CAA. EPA's substantive criteria for 
determining the adequacy of MVEBs are set out in 40 CFR 93.118(e)(4). 
Additionally, to approve a motor vehicle emissions budget EPA must 
complete a thorough review of the SIP, in this case the 
PM2.5 maintenance plans, and conclude that the SIP will 
achieve its overall purpose, in this case providing for maintenance of 
the 1997 annual and 2006 24-hour PM2.5 standards in the 
Detroit-Ann Arbor area.
    The maintenance plans submitted by Michigan for the area contains 
new primary PM2.5 and NOX MVEBs for the area for 
the year 2022. Michigan calculated the MVEBs using MOVES2010(a). After 
approval of the MVEBs becomes effective, the budgets will have to be 
used in future conformity determinations and regional emissions 
analyses prepared by the SEMCOG, and will have to be based on the use 
of MOVES2010a or the most recent version of MOVES required to be used 
in transportation conformity determinations.\13\ The state has 
determined the 2022 MVEBs for the Detroit-Ann Arbor area to be 4,360 
tpy for primary PM2.5 and 119,194 tpy for NOX. 
The budget for the Detroit-Ann Arbor area is equal to the mobile source 
emissions calculated for the attainment year of 2008. Michigan has 
decided to include ``safety margins'' as provided for in 40 CFR 
93.124(a) (described below) of 3,049 tpy for primary PM2.5 
and 91,183 tpy for NOX in the 2022 MVEBs, respectively, to 
provide for on-road mobile source growth. Michigan did not provide 
emission budgets for SO2, VOCs, and ammonia because it 
concluded, consistent with EPA's presumptions regarding these 
precursors, that emissions of these precursors from on-road motor 
vehicles are not significant contributors to the area's 
PM2.5 air quality problem.
---------------------------------------------------------------------------

    \13\ EPA described the circumstances under which an area would 
be required to use MOVES in transportation conformity determinations 
in its March 2, 2010, Federal Register notice officially releasing 
MOVES2010 for use in SIPs and transportation conformity 
determinations. (75 FR 9413)
---------------------------------------------------------------------------

    In the Detroit-Ann Arbor area, the motor vehicle budgets including 
the safety margins and motor vehicle emission projections for both 
NOX and PM2.5 are equal to the levels in the 
attainment year.
    EPA has reviewed the submitted budgets for 2022 including the added 
safety margins using the conformity rule's adequacy criteria found at 
40 CFR 93.118(e)(4) and the conformity rule's requirements for safety 
margins found at 40 CFR 93.124(a). EPA has also completed a thorough 
review of the maintenance plan for the Detroit-Ann Arbor area. Based on 
the results of this review of the budgets and the maintenance plans, 
EPA is approving the 2022 direct PM2.5 and NOX 
budgets, including the requested safety margins for the Detroit-Ann 
Arbor area. Additionally, EPA, through this rulemaking, has found the 
submitted budgets to be adequate for use to determine transportation 
conformity in the Detroit-Ann Arbor area, because EPA has determined 
that the area can maintain the 1997 annual PM2.5 NAAQS for 
the relevant maintenance period with on-road mobile source emissions at 
the levels of the MVEBs including the requested safety margins. These 
budgets must be used in conformity determinations made on or after the 
effective date of the final rulemaking (40 CFR 93.118(f)(iii)). 
Additionally, transportation conformity determinations made after the 
effective date of this notice must be based on regional emissions 
analyses using MOVES2010a or a more recent version of MOVES that has 
been approved for use in conformity determinations.\14\
---------------------------------------------------------------------------

    \14\ EPA described the circumstances under which an area would 
be required to use MOVES in transportation conformity determinations 
in its March 2, 2010 Federal Register notice officially releasing 
MOVES2010 for use in SIPs and transportation conformity 
determinations. (75 FR 9413)
---------------------------------------------------------------------------

b. What is a safety margin?
    A ``safety margin'' is the difference between the attainment level 
of emissions (from all sources) and the projected level of emissions 
(from all sources) in the maintenance plan. As shown in Table 5, 
overall emissions in the Detroit-Ann Arbor area are projected to 
decline by 118,943.42 tpy and 3,709.72 tpy for NOX and 
PM2.5 in 2022, respectively, which is greater than the MVEB 
safety margin of 91,183 tpy for NOX and 3,049 for primary 
PM2.5.
    The transportation conformity rule allows areas to allocate all or 
a portion of a ``safety margin'' to the area's motor vehicle emissions 
budgets (40 CFR 92.124(a)). The MVEBs requested by Michigan contain 
NOX and PM2.5 safety margins for mobile sources 
in 2022, which are much smaller than the allowable safety margins 
reflected in the total emissions for the Detroit-Ann Arbor area. The 
state is not requesting allocation to the MVEBs of the entire available 
safety margins reflected in the demonstration of maintenance. 
Therefore, even though the state is requesting MVEBs that exceed the 
projected on-road mobile source emissions for 2022 contained in the 
demonstration of maintenance, the increase in on-road mobile source 
emissions that can be considered for transportation conformity purposes 
is within the safety margins of the overall PM2.5 
maintenance demonstration. As discussed above, EPA is proposing that if 
this approval is finalized in 2013, the area will continue to maintain 
the 1997 annual and 2006 24-hour NAAQS through at least 2023. 
Consistent with this proposal, EPA is proposing to approve the motor 
vehicle emissions budgets submitted by the state in its July 5, 2011, 
maintenance plan for the Detroit-Ann Arbor area. EPA is proposing that 
the submitted budgets are consistent with maintenance of the 1997 
annual and 2006 24-hour PM2.5 NAAQS through 2023, 
specifically because the area is using the attainment year emissions as 
the MVEB for the future, which would remain the same into 2023.
    Therefore, EPA believes that the requested budgets, including the 
requested portion of the safety margins, provide for a quantity of 
mobile source emissions that would be expected to maintain the 
PM2.5 standard. Once allocated to mobile sources, these 
portions of the safety margins will not be available for use by other 
sources.
c. What action is EPA taking on the submitted motor vehicle emissions 
budgets?
    EPA, through this rulemaking, is proposing to find adequate and is 
approving the MVEBs for use to determine transportation conformity in 
the Detroit-Ann Arbor area, because EPA has determined that the area 
can maintain attainment of the 1997 annual and 2006 24-hour 
PM2.5 NAAQS for the relevant maintenance period with mobile 
source emissions at the levels of the MVEBs including the requested 
safety margins. (40 CFR 93.118(f)(iii))

6. 2005 Comprehensive Emissions Inventory

    As discussed above, section 172(c)(3) of the CAA requires areas to 
submit a comprehensive emissions inventory including direct PM and all 
four precursors (SO2, NOX, VOCs, and ammonia). 
EPA approved the Michigan 2005 base year emissions inventory on 
November 6, 2012 (77 FR 66547), fulfilling this requirement. Emissions 
contained in the submittals cover the general source categories of 
point sources, area sources, on-road mobile sources, and nonroad mobile 
sources.

[[Page 39670]]

    Based upon EPA's previous action, the 2005 emissions inventory was 
complete and accurate, and met the requirement of CAA section 
172(c)(3).

7. Summary of Proposed Actions

    EPA is proposing to determine that the Detroit-Ann Arbor area is 
attaining and will continue to attain the 1997 annual and 2006 24-hour 
PM2.5 standards. EPA is proposing to approve Michigan's 
PM2.5 maintenance plan for the Detroit-Ann Arbor area as a 
revision to the Michigan SIP because the plan meets the requirements of 
section 175A of the CAA. EPA is further proposing that the Detroit-Ann 
Arbor area has met the requirements for redesignation under section 
107(d)(3)(E) of the CAA. Therefore, EPA is proposing to grant the 
request from Michigan to change the legal designation of the Detroit-
Ann Arbor area from nonattainment to attainment for the 1997 annual and 
2006 24-hour PM2.5 NAAQS. Finally, for transportation 
conformity purposes EPA is also proposing to approve Michigan's MVEBs 
for the Detroit-Ann Arbor area.

VI. What are the effects of EPA's proposed actions?

    If finalized, approval of the redesignation request would change 
the official designation of the Michigan portion of the Detroit-Ann 
Arbor area for the 1997 annual and 2006 24-hour PM2.5 NAAQS, 
found at 40 CFR part 81, from nonattainment to attainment. If 
finalized, EPA's proposal would approve as a revision to the Michigan 
SIP for the Detroit-Ann Arbor area, the maintenance plan for the 1997 
annual and 2006 24-hour PM2.5 standard.

VII. Statutory and Executive Order Reviews

    Under the CAA, redesignation of an area to attainment and the 
accompanying approval of a maintenance plan under section 107(d)(3)(E) 
are actions that affect the status of a geographical area and do not 
impose any additional regulatory requirements on sources beyond those 
imposed by state law. A redesignation to attainment does not in and of 
itself create any new requirements, but rather results in the 
applicability of requirements contained in the CAA for areas that have 
been redesignated to attainment. Moreover, the Administrator is 
required to approve a SIP submission that complies with the provisions 
of the Act and applicable Federal regulations. 42 U.S.C. 7410(k); 40 
CFR 52.02(a). Thus, in reviewing SIP submissions, EPA's role is to 
approve state choices, provided that they meet the criteria of the CAA. 
Accordingly, this action merely proposes to approve state law as 
meeting Federal requirements and, if finalized, will not impose 
additional requirements beyond those imposed by state law. For that 
reason, these actions:
     Are not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Order 
12866 (58 FR 51735, October 4, 1993);
     do not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     are certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     do not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     do not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     are not economically significant regulatory actions based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     are not significant regulatory actions subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     are not subject to requirements of Section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the Clean Air Act; and
     do not provide EPA with the discretionary authority to 
address, as appropriate, disproportionate human health or environmental 
effects, using practicable and legally permissible methods, under 
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, this rule does not have tribal implications as 
specified by Executive Order 13175 (65 FR 67249, November 9, 2000), 
because the SIP is not approved to apply in Indian country located in 
the state, and EPA notes that it will not impose substantial direct 
costs on tribal governments or preempt tribal law.

List of Subjects

40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Particulate matter.

40 CFR Part 81

    Environmental protection, Air pollution control, National parks, 
Wilderness areas.

    Dated: June 19, 2013.
Susan Hedman,
Regional Administrator, Region 5.
[FR Doc. 2013-15887 Filed 7-1-13; 8:45 am]
BILLING CODE 6560-50-P
```