[Federal Register Volume 79, Number 32 (Tuesday, February 18, 2014)]
[Proposed Rules]
[Pages 9134-9152]
[FR Doc No: 2014-03314]

-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52 and 81

[EPA-R05-OAR-2012-0464; FRL-9906-41-Region-5]

Approval and Promulgation of Air Quality Implementation Plans;
Wisconsin; Redesignation of the Milwaukee-Racine 2006 24-Hour Fine
Particle Nonattainment Area to Attainment

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

-----------------------------------------------------------------------

SUMMARY: On June 8, 2012, the State of Wisconsin, through the Wisconsin
Department of Natural Resources (WDNR) submitted a request for the
Environmental Protection Agency (EPA) to redesignate the Milwaukee-
Racine fine particle (PM2.5) nonattainment area
(``Milwaukee-Racine Area'' or ``Area'') to attainment for the 2006 24-
hour PM2.5 National Ambient Air Quality Standard (NAAQS),
and to approve a state implementation plan (SIP) revision containing a
maintenance plan for the Area. The Milwaukee-Racine Area is comprised
of Milwaukee, Racine and Waukesha Counties. EPA is proposing to grant
the state's request to redesignate the Area to attainment for the 2006
24-hour PM2.5 NAAQS. EPA's proposed approval involves
several additional related actions. EPA is proposing to approve the
state's plan for maintaining the 2006 24-hour PM2.5 NAAQS
through 2025. EPA is proposing to approve the ammonia, volatile organic
compounds (VOC), nitrogen oxides (NOX), direct
PM2.5, and sulfur dioxide (SO2) inventories
submitted by the state as meeting the comprehensive emissions inventory
requirement of the Clean Air Act (CAA). Finally, EPA finds adequate and
is proposing to approve Wisconsin's NOX, direct
PM2.5, SO2, and VOC motor vehicle emission
budgets (MVEBs) for 2020 and 2025 for the Milwaukee Area. EPA is also
addressing a number of additional issues, including the effects of two
decisions of the United States Court of Appeals for the District of
Columbia (D.C. Circuit or Court): The Court's August 21, 2012, decision
to vacate and remand to EPA the Cross-State Air Pollution Rule (CSAPR);
and the Court's January 4, 2013, decision to remand two final rules
implementing the 1997 annual PM2.5 standard.

DATES: Comments must be received on or before March 20, 2014.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R05-
OAR-2012-0464, by one of the following methods:
    1. www.regulations.gov: Follow the on-line instructions for
submitting comments.
    2. Email<EMAIL_ADDRESS>    3. Fax:<PHONE_NUMBER>.
    4. Mail: Douglas Aburano, Chief, Attainment Planning and
Maintenance Section, Air Programs Branch (AR-18J), U.S. Environmental
Protection Agency, 77 West Jackson Boulevard, Chicago, Illinois 60604.
    5. Hand Delivery: Douglas Aburano, Chief, Attainment Planning and
Maintenance Section, Air Programs Branch (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-
2012-0464. 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 Gilberto Alvarez, Environmental
Scientist, at

(312) 886-6143 before visiting the Region 5 office.

FOR FURTHER INFORMATION CONTACT: Gilberto Alvarez, Environmental
Scientist, Attainment Planning and Maintenance Section, Air Programs
Branch (AR-18J), Environmental Protection Agency, Region 5, 77 West
Jackson Boulevard, Chicago, Illinois 60604,<PHONE_NUMBER>,
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,''
``us,'' or ``our'' is used, we mean EPA. This SUPPLEMENTARY INFORMATION
section is arranged as follows:

I. What should I consider as I prepare my comments for EPA?
II. What is the background for the proposal?
III. What are the criteria for redesignation to attainment?
IV. What is EPA's analysis of the state's request?
    A. Attainment Determination and Redesignation
    1. The Area Has Attained the 2006 24 PM2.5 NAAQS.
(Section 107(d)(3)(E)(i))
    2. The Area Has Met All Applicable Requirements Under Section
110 and part D; and the Area Has a Fully Approved SIP Under Section
110(k) of the CAA. (Sections 107(d)(3)(E)(v) and 107(d)(3)(E)(ii))
    3. The Improvement in Air Quality Is Due to Permanent and
Enforceable Reductions in Emissions Resulting from Implementation of
the SIP and Applicable Federal Air Pollution Control Regulations and
Other Permanent and Enforceable Reductions. (Section
107(d)(3)(E)(iii))
    4. The Area Has a Fully Approved Maintenance Plan Pursuant to
Section 175A of the CAA. (Section 107(d)(3)(E)(iv))
    B. Ammonia and VOC Comprehensive Emissions Inventories
    C. Wisconsin's MVEBs
    1. How are MVEBs Developed?
    2. What are the MVEBs for the Milwaukee-Racine area?
V. Summary of Proposed Actions
VI. 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).
    2. Follow directions--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 is the background for the proposal?

    Fine particulate pollution can be emitted directly from a source
(direct 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 ([mu]g/m\3\) of
ambient air, based on a three-year average of annual mean
PM2.5 concentrations at each monitoring site. In the same
rulemaking, EPA promulgated a 24-hour PM2.5 standard at 65
[mu]g/m\3\, based on a three-year average of the 98th percentile of 24-
hour PM2.5 concentrations at each monitoring site.
    On October 17, 2006, at 71 FR 61144, EPA retained the annual
PM2.5 standard at 15 [mu]g/m\3\ (2006 annual
PM2.5 standard), but revised the 24-hour standard to 35
[mu]g/m\3\, based again on the three-year average of the 98th
percentile of 24-hour PM2.5 concentrations at each monitor.
    On November 13, 2009, at 74 FR 58688, EPA published air quality
area designations for the 2006 24-hour PM2.5 standard. In
that rulemaking, EPA designated the Milwaukee-Racine Area as
nonattainment for the 2006 24-hour PM2.5 standard and
defined the area to include Milwaukee, Racine and Kenosha Counties.
    In response to legal challenges of the 2006 annual PM2.5
standard, the D.C. Circuit 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). On
December 14, 2012, EPA finalized a rule revising the PM2.5
annual standard to 12 [mu]g/m\3\ based on current scientific evidence
regarding the protection of public health. EPA is not addressing the
2012 annual PM2.5 standard in this proposal.
    On April 24, 2012, and December 28, 2012, EPA proposed and
reproposed, respectively, to determine that the Area was in attainment
for the 2006 24-hour PM2.5 NAAQS (77 FR 24436 and 77 FR
76427), based on certified ambient monitoring data for the 2008-2010
monitoring period.
    On June 8, 2012, the Wisconsin Department of Natural Resources
(WDNR), submitted a request for EPA to redesignate the Milwaukee-Racine
Area to attainment for the 2006 24-hour PM2.5 NAAQS, and for
EPA approval of the SIP revision containing an emissions inventory and
a maintenance plan for the area.
    On May 30, 2013, WDNR submitted ammonia and VOC emissions
inventories to supplement previously submitted emissions inventories.
    In this proposed redesignation, EPA takes into account two
decisions of the D.C. Circuit. In the first of the two Court decisions,
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), vacated and remanded 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, in
Natural Resources Defense Council v. EPA, 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), 706 F.3d
428 (D.C. Cir. 2013).

III. 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 and 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.

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

A. Attainment Determination and Redesignation

    As noted above, on April 24, 2012, at 77 FR 24436, EPA proposed to
determine that the Milwaukee-Racine Area attained the 2006 24-hour
PM2.5 standard by the applicable attainment date. EPA is
here updating and elaborating upon that proposal. We received comments
and we are updating the information, based on those comments, within
this proposed redesignation. EPA is proposing to determine that the
area continues to attain the 2006 24-hour PM2.5 standard
with certified 2010-2012 monitoring data. EPA is also proposing to
approve Wisconsin's maintenance plan for the area and to determine that
the area has met all other applicable redesignation criteria under CAA
section 107(d)(3)(E). The basis for EPA's proposed approval of the
redesignation request is as follows:
1. The Area Has Attained the 2006 24-Hour PM2.5 NAAQS.
(Section 107(d)(3)(E)(i))
    In this action EPA is proposing to redesignate the Milwaukee-Racine
Area as having attained the 2006 24-hour PM2.5 NAAQS based
on quality-assured, certified data for the 2010-2012 monitoring period.
Data available for 2013 indicate that the area continues to attain the
standard. EPA's determination that an area has attained the 2006 24-
hour PM2.5 NAAQS is made in accordance with 40 CFR 50.13 and
part 50, appendix N, based on three consecutive calendar years of
complete quality-assured air quality monitoring data. For an area to
attain the 2006 24-hour PM2.5 standard, the three-year
average of the 98th percentile 24-hour concentrations must not exceed
35 [mu]g/m\3\ at all relevant monitoring sites in the subject area.
Under 40 CFR part 50, appendix N 4.2(a), a year of 24-Hour
PM2.5 data meets completeness requirements when at least 75
percent of the scheduled sampling days for each quarter have valid
data. Section 4.2(b) provides further that ``The use of less than
complete data is subject to the approval of EPA which may consider
factors such as monitoring site closures/moves, monitoring diligence,
and nearby concentrations in determining whether to use such data for
comparisons to the NAAQS.''
    The state's redesignation request for the Milwaukee-Racine area
includes monitoring data for the 2008-2010 time period. In addition,
certified monitoring data are also now available for the 2009-2011,
2010-2012 and 2013 time periods. In addition, on January 23, 2013, WDNR
submitted draft 2013 data for the area. Table 1, below, provides a
summary of the PM2.5 24-hour air quality monitoring data for
the years 2008-2012. Table 2, below, provides the design values for the
2008-2010, 2009-2011 and 2010-2012 (through mid-November) time periods.
Exceedances in the Milwaukee area generally occur in the first quarter
of the year, so that the data that are available for 2013 are likely to
be a good indication of air quality for the full year.

       Table 1--98th Percentile 24-Hour PM2.5 Concentrations for the Milwaukee-Racine Area ([micro]g/m\3\)
----------------------------------------------------------------------------------------------------------------
                                                        98th Percentile 24-hour concentrations
           Site name                Monitor    -----------------------------------------------------------------
                                                   2008       2009       2010       2011       2012       2013
----------------------------------------------------------------------------------------------------------------
Milw-DNR SERHQ................       550790026       27.5       39.0       32.6       21.3       24.6       19.0
Waukesha......................       551330027       29.9       32.0       35.9       25.3       20.9       23.6
Milw-16th CHC.................       550790010       27.3       39.1       30.9       27.0       30.4       23.7
Milw-FAA/College Ave..........       550790058         **      *26.5      *35.3      *25.4       27.3       19.2
Virginia Street...............       550790043       27.4       41.7         **         **         **         **
Wells Street..................       550790099       29.0       40.3         **         **       30.2       19.7
----------------------------------------------------------------------------------------------------------------
2013 data are complete through mid-November.
* Indicates incomplete data.
** Indicates no data due to monitor not operating.

        Table 2--2006 24-Hour PM2.5 Standard Design Values for the Milwaukee-Racine Area ([micro]g/m\3\)
----------------------------------------------------------------------------------------------------------------
                    Site name                         Monitor        2008-2010       2009-2011       2010-2012
----------------------------------------------------------------------------------------------------------------
Milw-DNR SERHQ..................................       550790026              33              31              26
Waukesha........................................       551330027              33              31              27
Milw-16th CHC...................................       550790010              32              32              29
Milw-FAA/College Ave............................       550790058             *31             *29             *29
Virginia Street.................................       550790043         **35/34             ***             ***
Wells Street....................................       550790099         **35/34             ***             ***
----------------------------------------------------------------------------------------------------------------
* Indicates invalid three-year averages due to missing data.
** First value is computed from an incomplete set of monitoring data; second value also considers imputed
  values.
*** No averages calculated because data were missing from one or more years.

    The data in Tables 1 and 2 show that all relevant PM2.5
monitors in the Milwaukee-Racine Area have recorded PM2.5
concentrations attaining the 2006 24-hour PM2.5 NAAQS during
the 2008-2010, 2009-2011, 2010-2012 and 2013 time periods (no violation
of the 2006 24-hour PM2.5 NAAQS has been recorded at any
monitoring site). As demonstrated in Table 1, the data for 2013 through
mid-November continue to support a final determination of attainment of
the 24-hour PM2.5 NAAQS for the Milwaukee area. However,
because the area experienced data completeness issues due to the
shutdown of two monitors (Virginia Street, 550790043 and Wells Street,

5507900099, respectively) in 2010, EPA has evaluated whether the data
may still be used, pursuant to the provisions of 50 CFR Appendix N
section 4.2(b). EPA conducted an analysis of the data, deriving the
concentrations that might have been expected at the shutdown monitoring
sites during the shutdown period, based on observed concentrations at
nearby sites, as explained below.
    Aside from Virginia and Wells monitors, EPA notes that the design
value for the College Avenue monitor in table 2 is based on incomplete
data. However, this is not the design value monitor (i.e., it is not
the monitor that had the highest value at the time of designation) for
the area and a comparison of the values from the remaining monitors
within the nonattainment area indicate that those values are reflective
of values that one would expect at College Avenue, which are all below
the 2006 24-hour PM2.5 NAAQS. As shown in Table 1, the data
continue to show a decline in concentrations.
    On April 24, 2012, and December 28, 2012, EPA proposed and
reproposed, respectively, to determine that the area was in attainment
(77 FR 24436 and 77 FR 76427), based on certified ambient monitoring
data for the 2008-2010 monitoring period. EPA is here updating and
elaborating upon that proposal. We received comments and we are
updating the information, based on those comments, within this proposed
redesignation.
    EPA received two comments from one commenter, Midwest Environmental
Defense Center, on our April 24, 2012, proposed rule. The first comment
objected to the EPA's use of a statistical analysis to impute a design
value for the Wells Street monitor (Site Number 550790099), which did
not record data during 2010 and 2011, and which had previously recorded
data showing nonattainment. The commenter contended that EPA erred in
substituting a design value for this monitor and that EPA's analysis
does not establish a direct correlation between the shut down monitors
and a nearby operating monitor. On December 14, 2011, EPA requested the
restart of the Wells Street monitor (Site Number 55079099). The monitor
restarted operation on January 1, 2012, and it has been recording data
since that time. The state was diligent in restarting the monitor in
consultation with EPA. Data available to date for this monitor site
through 2013 are consistent with continued attainment. Data for all
four quarters of 2012 is complete and 2013 data has 3 complete
quarters.
    EPA relied on the data imputation technique because two of the
monitors were shut down (Site Numbers 550790043 and 550790099) and did
not record data during 2010. As discussed in the proposal, EPA relied
on this statistical analysis technique because * * * ``In situations
like those in Milwaukee, where there are missing or incomplete data due
to monitor shutdown or other factors, EPA believes that it is often
appropriate to use historical data along with statistical techniques to
impute missing data, use those imputed data to estimate the three-year
design value that would likely have occurred if complete data had been
obtained, and thereby determine if the monitor in question would likely
have met the NAAQS.'' (77 FR 24436)
    The commenter stated that we incorrectly implied ``. . . that the
compared monitors recorded similar data, when in truth, there is not a
direct correlation between the data.'' EPA disagrees that there is not
enough correlation between the shut down monitor site and the
comparison monitor site. In fact, all four monitoring sites in the
nonattainment area correlate very well with the replaced monitor.
Wisconsin has provided EPA with an analysis comparing the correlations
between the shut down monitor to the other four monitors within the
nonattainment area, using data from January 1, 2012, through April 9,
2012, when all monitors collected data. The correlations from that
analysis are summarized in Table 3.
    EPA understands that the publicly available data we relied upon for
our imputation is technically listed as ``invalid'', due to the
shutdown of several monitors, resulting in incomplete data. However,
section 4.2(b) provides that ``The use of less than complete data is
subject to the approval of EPA which may consider factors such as
monitoring site closures/moves, monitoring diligence, and nearby
concentrations in determining whether to use such data for comparisons
to the NAAQS.
    Therefore, based upon our statistical analysis, for the purposes of
this redesignation, we believe all the monitors are meeting the 2006
24-hour PM2.5 NAAQS. In addition, Wisconsin restarted one of
the shutdown monitors, and data from 2012 and the available data from
2013 for this site show concentrations well below the standard, and
these data show that concentrations at the site continue to be well
correlated with concentrations at the other monitoring site from which
EPA estimated imputed values for 2010. Other data available to date
from 2013 and included in Table 1 are also consistent with continued
attainment.

                     Table 3--Correlations Analysis
------------------------------------------------------------------------
                                                   Site      Correlation
                   Site name                      number       factor
------------------------------------------------------------------------
Milw-DNR SERHQ................................   550790026         0.997
Waukesha......................................   551330027         0.919
Milw-16th CHC.................................   550790010         0.992
Milw-FAA/College Ave..........................   550790058         0.997
------------------------------------------------------------------------

    Moreover, in order to account for the uncertainty inherent within
the analysis, EPA used another statistical technique to account for the
variability in the data from the original site as well as the data from
the correlated comparison monitors. The statistical analysis, known as
``bootstrapping'' was developed by the Office of Air Quality Planning
and Standards to aid in predicting annual PM2.5 design
values in areas which did not meet specific data completeness
requirements. A more detailed description of the bootstrapping analysis
can be found within the technical support document to our April 24,
2012, notice proposing approval of a determination of attainment (77 FR
24436). In summary, a series of mathematical equations using
observations yields linear regression to relate the concentrations from
the shutdown sites to a base site containing 2010 data.
    The results of that analysis provided EPA with further evidence to
support a final determination of attainment of the 24-hour
PM2.5 NAAQS for the Milwaukee area.
    EPA's use of these data analysis techniques to address incomplete
data in making attainment determinations for the PM2.5 NAAQS
is well established. See 75 FR 45076 (August 2, 2010) (New York-NJ-CT
1997 annual PM2.5 NAAQS) and 76 FR 27290 (May 11, 2011)
Huntington-Ashland (OH, WV, KY) 1997 annual PM2.5 NAAQS.
    Therefore, pursuant to 50 CFR Appendix N, section 4.2(b), EPA is
expressly approving the use of less than complete data after
considering relevant factors. These include site closures and moves,
monitoring diligence, nearby concentrations and monitor correlations,
as well as additional complete data acquired in 2012 and 2013 that show
continued attainment in the area.

2. The Area Has Met All Applicable Requirements Under Section 110 and
Part D; and the Area Has a Fully Approved SIP Under Section 110(k).
(Sections 107(d)(3)(E)(v) and 107(d)(3)(E)(ii))
    We have determined that Wisconsin's SIP meets all applicable SIP
requirements for purposes of redesignation for the Milwaukee-Racine
Area under section 110 of the CAA (general SIP requirements) and 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, with the exception of the emissions
inventory under section 172(c)(3), we have approved all applicable
requirements of the Wisconsin SIP for purposes of redesignation, in
accordance with section 107(d)(3)(E)(ii). As discussed below, in this
action EPA is proposing to approve Wisconsin's 2006 and 2010 emissions
inventories as meeting the section 172(c)(3) comprehensive emissions
inventory requirement.
    In making these determinations, we have ascertained which SIP
requirements are applicable to the area for purposes of redesignation,
and have determined that there are SIP measures meeting those
requirements and that they are fully approved under section 110(k) of
the CAA.
a. The Milwaukee-Racine Area Has Met All Applicable Requirements for
Purposes of Redesignation 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: (1) Include enforceable emission limitations and other
control measures, means or techniques necessary to meet the
requirements of the CAA; (2) provide for establishment and operation of
appropriate devices, methods, systems, and procedures necessary to
monitor ambient air quality; (3) provide for implementation of a source
permit program to regulate the modification and construction of any
stationary source within the areas covered by the plan; (4) include
provisions for the implementation of part C, Prevention of Significant
Deterioration (PSD) and part D, New Source Review (NSR) permit
programs; (5) include criteria for stationary source emission control
measures, monitoring, and reporting; (6) include provisions for air
quality modeling; and (7) 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 holds 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 conclude that these requirements should not
be construed to be applicable requirements for purposes of
redesignation.
    Further, 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. Only the
section 110 and part D requirements that are linked with a particular
area's designation are the relevant measures that we may consider in
evaluating a redesignation request. This approach is consistent with
EPA's existing policy on applicability of conformity and oxygenated
fuels requirements for redesignation purposes, as well as with section
184 ozone transport requirements. 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 Wisconsin SIP and have concluded that it meets
the general SIP requirements under section 110 of the CAA to the extent
these requirements are applicable for purposes of redesignation. EPA
has previously approved provisions of Wisconsin's SIP addressing
section 110 requirements, including provisions addressing particulate
matter, at 40 CFR 52.1870. On January 24, 2011, and June 29, 2012,
Wisconsin submitted ``infrastructure SIP'' elements required by section
110(a)(2) of the CAA. EPA approved elements of Wisconsin's submittals
on October 29, 2012, at 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 Milwaukee-Racine Area.
Therefore, EPA believes that these SIP requirements are not applicable
for purposes of review of the state's PM2.5 redesignation
requests.
ii. Part D Requirements
    EPA is proposing to determine that, upon approval of the
comprehensive emissions inventories discussed in section IV.B. of this
rulemaking, the Wisconsin SIP will meet the applicable SIP requirements
for the Milwaukee-Racine 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. Subpart 4 of part D, found in sections 185-
190 of the CAA, provides more specific requirements for particulate
matter nonattainment areas.
(1) Subpart 1
(a) Section 172 Requirements
    For purposes of evaluating these redesignation requests, the
applicable section 172 SIP requirements for the Milwaukee-Racine Area
are contained in sections 172(c)(1)-(9) of the CAA. 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 (health-based NAAQS). EPA interprets
this requirement to impose a duty on all nonattainment areas to
consider all available control measures 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 attainment
has been reached in the Milwaukee-Racine Area, no additional measures
are needed 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 is finalized.
See 40 CFR 51.1004(c).
    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 redesignation because the Milwaukee-Racine Area is
monitoring attainment of the 2006 24-hour PM2.5 NAAQS. Id.
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.
Wisconsin submitted 2006 emissions inventories for direct
PM2.5, NOX, SO2 and VOC along with its
redesignation request and supplemented the inventories with 2007
ammonia emissions on May 30, 2013. As discussed below in section IV.B.,
EPA is proposing to approve the emission inventories submitted by
Wisconsin as meeting the section 172(c)(3) emissions inventory
requirement for the Milwaukee-Racine Area.
    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 Wisconsin's current
NSR program on January 18, 1995 (60 FR 3538). 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'' (Nichols memorandum).
Wisconsin has demonstrated that the Milwaukee-Racine 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 Milwaukee-Racine 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, 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 find that the
Wisconsin SIP meets the section 110(a)(2) requirements applicable 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).
    Section 176(c) of the CAA was amended by provisions contained in
the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A
Legacy for Users (SAFETEA-LU), which was signed into law on August 10,
2005, (Public Law 109-59). Among the changes Congress made to this
section of the CAA were streamlined requirements for state
transportation conformity SIPs. State transportation conformity
regulations must be consistent with Federal conformity regulations and
address three specific requirements related to consultation,
enforcement and enforceability.
    EPA interprets the conformity SIP requirements as not applying for
purposes of evaluating the redesignation request under section 107(d)
because the requirement to submit SIP revisions to comply with the
conformity provisions of the CAA continues to apply to areas after
redesignation to attainment, since such areas would be subject to a
section 175A maintenance plan. Therefore, because areas are subject to
the conformity requirements regardless of whether they are redesignated
to attainment, it is reasonable to view these requirements as not
applying for purposes of evaluating a redesignation request. See Wall
v. EPA, 265 F.3d 426 (6th Cir. 2001), upholding this interpretation.
See also 60 FR 62748, 62749-62750 (Dec. 7, 1995) (Tampa, Florida). EPA
approved Wisconsin's general and transportation conformity SIPs on July
29, 1996, (61 FR 39329) and August 27, 1996, (61 FR 43970),
respectively. Wisconsin is in the process of updating its approved
transportation conformity SIP, and EPA will review its provisions when
they are submitted.
    Wisconsin has submitted onroad MVEBs for the Milwaukee-Racine Area
of 2.33 tons per winter day \1\ (tpwd) and 2.16 tpwd direct
PM2.5 and 32.62 tpwd and 28.69 tpwd NOX for the
years 2020 and 2025, respectively. The area must use the MVEBs from the
maintenance plan in any conformity determination that is made on or
after the effective date of the adequacy finding and maintenance plan
approval.
---------------------------------------------------------------------------

    \1\ Wisconsin's nonattainment violations occurred for 24-hour
average time periods. Therefore, it was necessary to construct
emissions inventories for a time period that is most associated with
elevated levels of 24-hour PM2.5 concentrations. A
Wisconsin-specific study identified the meteorological winter months
of December, January, January and February as having both the
highest monthly average PM2.5 concentrations and the
highest monthly percentage of site-days with 24-hour concentrations
greater than 30 [micro]g/m\3\. Accordingly, Wisconsin designed and
constructed emission inventories for this PM2.5
redesignation request to focus on pollution-related activity levels
during the winter months (more specifically--for an average January
weekday). Thus, emissions inventory values are referenced as tons
per winter day (tpwd).
---------------------------------------------------------------------------

(2) Effect of the January 4, 2013, D.C. 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 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) (collectively, ``1997
PM2.5 Implementation Rule''). 706 F.3d 428 (D.C. Cir. 2013).
The Court found that EPA erred in implementing the 1997 annual
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 24-
hour PM2.5 standard, EPA is taking into account the Court's
position on subpart 4 and the 1997 annual 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 Milwaukee-Racine 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 of the
redesignation provisions of the CAA hold 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. Even if
EPA applies the subpart 4 requirements to the Milwaukee-Racine
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 and
the voluntary remand of the 2006 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 and
2006 PM2.5 NAAQS under subpart 4 of part D of the CAA, in
addition to subpart 1. For the purposes of evaluating Wisconsin'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 Milwaukee-Racine redesignation. Under its longstanding
interpretation of the CAA, EPA has interpreted section 107(d)(3)(E) to
mean, as a threshold matter, 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)
National Ambient Air Quality Standards (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'').\2\ In this case, at the time that Wisconsin
submitted its redesignation request, requirements under subpart 4 were
not due, and indeed, were not yet known to apply, as the state's
submittal was prior to the D.C. Circuit's decision.
---------------------------------------------------------------------------

    \2\ 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 Milwaukee-Racine
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, 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 to an ongoing obligation to adopt new CAA
requirements that arose after the state submitted its redesignation
request, in order to be redesignated, 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 June 8, 2012, but the Court did not issue its
decision remanding EPA's 1997 PM2.5 implementation rule and
the voluntary remand of the 2006 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 its January, 2013, decision on the 1997
PM2.5 Implementation rule, 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),\3\ 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 Wisconsin by
rejecting its redesignation request for an area that is already
attaining the 2006 24-hour 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.
---------------------------------------------------------------------------

    \3\ 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 Wisconsin's Redesignation Request
    Even if EPA were to take the view that the Court's January 4, 2013,
decision requires that, in the context of a pending redesignation for
the 2006 PM2.5 standard, subpart 4 requirements were due and
in effect at the time the state submitted its redesignation request,
EPA finds that the Milwaukee-Racine Area still qualifies for
redesignation to attainment. As explained below, EPA believes that the
redesignation request for the Milwaukee-Racine 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 Milwaukee-Racine 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 \4\ 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, RFP, emissions inventories, and contingency
measures.
---------------------------------------------------------------------------

    \4\ PM10 refers to particulates nominally 10
micrometers in diameter or smaller.
---------------------------------------------------------------------------

    For the purposes of this redesignation, in order to identify any
additional requirements that would apply under subpart 4, we are
considering the Milwaukee-Racine Area to be a ``moderate''
PM2.5 nonattainment area. Under section 188 of the CAA, all
areas designated nonattainment 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 areas as ``serious'' nonattainment areas. 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. Sections 189(a) and (c) of
subpart 4 apply to moderate nonattainment areas and include 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.\5\ 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 the
Nichols memorandum. 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).
---------------------------------------------------------------------------

    \5\ 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,\6\ when EPA evaluates a redesignation request under either
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 consistently interpreted
attainment-linked requirements as not applicable for areas attaining
the standard. In the General Preamble, EPA stated that:
---------------------------------------------------------------------------

    \6\ 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 Clean
Air Act 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, ``The
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 \7\
and thus are now past due, those requirements do not apply to an area
that is attaining the 2006 24-hour 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).
---------------------------------------------------------------------------

    \7\ 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 2006 24-hour PM2.5 standard, because 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 section 172(c)(1) and section 189(a)(1)(c), a RFP demonstration
under 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. EPA, in this section
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 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, ``In 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 its opinion, however, the Court observed:

    Ammonia 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 Milwaukee-Racine 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
the Milwaukee-Racine Area, EPA believes that proposing redesignation of
the Milwaukee-Racine area for the 2006 24-hour PM2.5
standard is consistent with section 189(e) of the CAA. The Milwaukee-
Racine Area has attained the standard without any specific additional
controls of ammonia emissions from any sources in the area.
    Precursors in subpart 4 are specifically regulated under the
provisions of section 189(e), which require, with important exceptions,
control requirements for major stationary sources of PM10
precursors.\8\ 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 2006 24-hour 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.
---------------------------------------------------------------------------

    \8\ 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 VOC under other CAA requirements may suffice to relieve
a state from the need to adopt precursor controls under section 189(e).
57 FR 13542. EPA proposes to determine that the SIP has met the
provisions of section 189(e) with respect to ammonia and VOCs as
precursors. This proposed determination is based on our findings that:
(1) The Milwaukee-Racine 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.\9\ 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 2006
24-hour PM2.5 standard, at present ammonia and VOC
precursors from major stationary sources do not contribute
significantly to PM2.5 levels exceeding the 2006 24-hour
PM2.5 standard in the Milwaukee-Racine Area. See 57 FR
13539-42.
---------------------------------------------------------------------------

    \9\ The Milwaukee-Racine Area has reduced VOC emissions through
the implementation of various control programs including VOC
Reasonably Available Control Technology regulations and various
onroad and nonroad motor vehicle control programs.
---------------------------------------------------------------------------

    EPA's 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 2006 24-hour 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 Wisconsin to address precursors
differently than they have 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
purposes.\10\ Courts have upheld this approach to the requirements of
subpart 4 for PM10.\11\ EPA believes that application of
this approach to PM2.5 precursors under subpart 4 is
reasonable. Because the Milwaukee-Racine Area has already attained the
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, in evaluating this redesignation request, to
consider additional precursors under subpart 4, it would not affect
EPA's approval here of Wisconsin's request for redesignation of the
Milwaukee-Racine Area. In the context of a redesignation, the area has
shown that it has attained the standard. 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 Milwaukee-Racine Area to
attainment for the 2006 24-hour PM2.5 NAAQS at this time.
---------------------------------------------------------------------------

    \10\ 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).
    \11\ See, e.g., Assoc. of Irritated Residents v. EPA et al., 423
F.3d 989 (9th Cir. 2005).
---------------------------------------------------------------------------

    In sum, even if Wisconsin was required to address precursors for
the Milwaukee-Racine 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).
(iv) Maintenance Plan and Evaluation of Precursors
    A discussion of the impact of the Court's decision on the
maintenance plan required under sections 175A and 107(d)(3)(E)(iv) can
be found in section IV.A.5.d., below.
b. The Milwaukee-Racine Area Has a Fully Approved Applicable SIP Under
Section 110(k) of the CAA
    Upon final approval of Wisconsin's comprehensive emissions
inventory, EPA will have fully approved the Wisconsin SIP for the
Milwaukee-Racine Area under section 110(k) of the CAA for all
requirements applicable for purposes of redesignation. EPA may rely on
prior SIP approvals in approving a redesignation request (See page 3 of
the

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, Wisconsin has adopted
and submitted, and EPA has fully approved, provisions addressing
various required SIP elements under particulate matter standards. In
this action, EPA is proposing to approve Wisconsin's 2006 comprehensive
emissions inventory for VOC, SO2, NOX and
PM2.5 as well as the 2007 supplemental inventory for ammonia
for the Milwaukee-Racine Area as meeting the requirement of section
172(c)(3) of the CAA. No Milwaukee-Racine Area SIP provisions are
currently disapproved, conditionally approved, or partially approved.
3. The Improvement in Air Quality Is Due to Permanent and Enforceable
Reductions in Emissions Resulting From Implementation of the SIP and
Applicable Federal Air Pollution Control Regulations and Other
Permanent and Enforceable Reductions (Section 107(d)(3)(E)(iii))
    EPA finds that Wisconsin has demonstrated that the observed air
quality improvement in the Milwaukee-Racine Area is due to permanent
and enforceable reductions in emissions resulting from implementation
of the SIP, Federal measures, and other state-adopted measures.
    In making this showing, Wisconsin has calculated the change in
emissions between 2006, one of the years in the period during which the
Milwaukee-Racine Area monitored nonattainment, and 2010, one of the
years in the period during which the Milwaukee-Racine 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 Milwaukee-Racine Area
and upwind 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. Consent Decrees
    A May 7, 2010, consent decree with Saint-Gobain Containers required
the Burlington Plant, located in Burlington, Wisconsin, to install oxy-
fuel technology and to be subjected to a NOX emission limit
of 1.3 pounds per ton of glass produced. The facility is also subjected
to an SO2 emissions limit of 0.8 pounds per ton of glass
produced. An August 2, 2010, consent decree requires Silgan Containers
Manufacturing Plants in Menomonee Falls and Oconomowoc to reduce VOC
emissions by approximately 10 tons per year (tpy) in Oconomowoc and to
eliminate another 86.3 tpy of VOC emissions from their Menomonee Falls
facility.
ii. Federal Emission Control Measures
    Reductions in fine particle precursor emissions 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 VOC,
NOX, and SO2 emissions from new cars and light
duty trucks, including sport utility vehicles. The Federal rules were
phased in between 2004 and 2009. The EPA has estimated that, by the
time post-2009 vehicles have entirely replaced pre-2009 vehicles, the
following vehicle NOX emission reductions will have occurred
nationwide: Passenger cars (light duty vehicles) (77 percent); light
duty trucks, minivans, and sports utility vehicles (86 percent); and,
larger sports utility vehicles, vans, and heavier trucks (69 to 95
percent). Some of the emissions reductions resulting from new vehicle
standards occurred during the 2008-2010 attainment period; however,
additional reductions will continue to occur throughout the maintenance
period 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. Gasoline sold in the region including
Wisconsin prior to implementation of the Tier 2 sulfur content limits
had an average sulfur content of 276 ppm.\12\
---------------------------------------------------------------------------

    \12\ See Regulatory Impact Analysis--Control of Air Pollution
From New Motor Vehicles: Tier 2 Motor Vehicle Emissions Standards
and Gasoline Sulfur Control Requirements, December 1999, EPA420-R-
99-023, p. IV-42.
---------------------------------------------------------------------------

    Heavy-Duty Diesel Engine Rule. This rule, which EPA issued in July
2000, limited the sulfur content of diesel fuel beginning in 2004. A
second phase took effect in 2007 which 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
achieve a 90 percent reduction in direct PM2.5 emissions and
a 95 percent reduction in NOX emissions for these new
engines using low sulfur diesel, compared to existing engines using
higher sulfur content diesel. The reductions in fuel sulfur content
occurred by the 2008-2010 attainment period. Some of the emissions
reductions resulting from new vehicle standards occurred during the
2008-2010 attainment period, however additional reductions will
continue to occur throughout the maintenance period as the fleet of
older heavy duty diesel engines turns over. 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, which established engine emission
standards to be phased in between 2008 and 2014. The rule also required
reductions to the sulfur content in nonroad diesel fuel by over 99
percent. 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 percent,
compared to current nonroad engines using higher sulfur content diesel.
The reduction in fuel sulfur content yielded an immediate reduction in
sulfate particle emissions from all diesel vehicles. In addition, some
emissions reductions from the new engine emission standards were
realized over the 2008-2010 time period, although most of the
reductions will occur over the maintenance period as the fleet of older
nonroad diesel engines turns over.
    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 are being phased in from 2006 through 2012.
Marine Diesel engine standards were phased in from 2006 through 2009.
With full

implementation of all of the nonroad spark-ignition engine and
recreational engine standards, an overall 72 percent reduction in VOC,
80 percent reduction in NOX and 56 percent reduction in
carbon monoxide (CO) emissions are expected by 2020. Some of these
emission reductions occurred by the 2008-2010 attainment period and
additional emission reductions will occur during the maintenance period
as the fleet turns over.
iii. Control Measures Implemented in Wisconsin and in Upwind Areas
    CAIR and CSAPR. EPA promulgated CSAPR (76 FR 48208, August 8,
2011), to replace CAIR, which has been in place since 2005. See 76 FR
59517. CAIR 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 D.C. Circuit 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).
    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 in EME Homer City (No. 11-1302 and consolidated cases).
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 filed petitions
for certiorari to the U.S. Supreme Court. On June 24, 2013, the Supreme
Court granted certiorari and agreed to review the D.C. Circuit's
decision in EME Homer City. The Supreme Court's grant of certiorari, by
itself, does not alter the status of CAIR or CSAPR. At this time, CAIR
remains in place.
    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 requests and the related SIP
revisions for the Milwaukee-Racine Area, including Wisconsin's plan for
maintaining attainment of the PM2.5 standard.
    As directed by the D.C. Circuit, CAIR remains in place and
enforceable until substituted by a valid replacement rule. Wisconsin
submitted a CAIR SIP which was approved by EPA on October 16, 2007 (72
FR 58542). In its redesignation request, Wisconsin notes that all
potential emission reductions resulting from CAIR and CSAPR have been
left out of the maintenance emission inventory projections.
    Although Wisconsin is not relying on CAIR in its maintenance plan,
the 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 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 who 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 also, 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.
b. Emission Reductions
    Wisconsin developed annual emissions inventories for VOC,
NOX, direct PM2.5, and SO2 for 2006,
one of the years the Milwaukee-Racine Area monitored nonattainment 2006
24-hour PM2.5 standard, and 2010, one of the years the area
monitored attainment of the standard. In some circumstances, seasonal
inventories may be useful for the 24-hour standard. For example, in
some nonattainment areas, all of the highest PM2.5
concentrations occur in one season. In the case of the Milwaukee-Racine
Area, Wisconsin analyzed the PM2.5 monitoring data and found
that violations occurred for 24-hour average time periods during the
Winter.
    Therefore, it was necessary to construct emission inventories for a
time period that is most associated with elevated levels of 24-hour
PM2.5 concentrations. Within Wisconsin's redesignation
request package, the state references a 2011 PM2.5 study
that evaluated the collective month-of-year profiles of average 24-hour
FRM PM2.5 levels during 1999-2010. This assessment
identified the meteorological winter months of December, January, and
February as having both the highest monthly average PM2.5
concentrations and the highest monthly percentage of site-days with 24-
hour PM2.5 concentrations greater than 30 [mu]g/m3.
Accordingly, the state designed and constructed emission inventories
for their PM2.5 redesignation request to focus on pollution-
related activity levels during the winter months (more specifically--
for an average January weekday).
    The emission inventories submitted by Wisconsin were developed with
the assistance of the Lake Michigan Air Directors Consortium (LADCO).
The main purpose of LADCO is to provide technical assessments for and
assistance to its member states on problems of air

quality. LADCO's primary geographic focus is the area encompassed by
its member states (Illinois, Indiana, Michigan, Ohio, Minnesota and
Wisconsin) and any areas which affect air quality in its member states.
    The 2006 nonattainment inventory was developed as described below.
Point source emissions for 2006 were estimated using linear
interpolations from 2005 to 2008 emissions inventories. The 2005 and
2008 emissions inventories were created using annually reported point
source emissions, EPA's Clean Air Markets Database and approved U.S.
EPA techniques for emissions calculation (e.g., emission factors).
Whenever feasible, Federal, state and local controls were factored into
the emission calculations. Emissions were estimated by collecting
process level information from each facility that qualifies for
inclusion into the state's point source database.
    Area source sector emissions were created by backcasting the
Wisconsin 2008 base year emissions inventory submitted to EPA in 2010
for the National Emissions Inventory. The backcasting factors were
primarily based on growth factors from the Economic Growth and Analysis
System model.
    The 2006 nonroad mobile emission estimates were created by using
EPA's National Mobile Inventory (NMIM) model (2009/05/04 Version). The
2006 aircraft, marine and rail emissions were estimated using linear
interpolation from the 2005 and 2008 emissions inventories. Pechan
provided marine and rail emission estimates via LADCO for Wisconsin.
Pechan is an independent contractor, which, through contracts with
LADCO, has developed state-specific emission inventory data, including
growth factors, for the entire LADCO region. Aircraft emissions were
calculated using the Federal Aviation Administration's Emissions and
Dispersion Modeling System (EDMS).
    The 2006 onroad mobile emission estimates were created by using the
EPA's MOVES2010a model.
    The 2010 attainment year inventories were developed using the same
techniques as those used to develop the nonattainment year inventories.
    NOX, direct PM2.5, SO2, and VOC
emissions data are shown in Table 4 below.

           Table 4--Comparison of 2006 and 2010 NOX, direct PM2.5, SO2, and VOC Emission Totals by Source Sector in Tons per Winter Day (tpwd)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                   2006                                    2010                            Net change 2006-2010
             Sector              -----------------------------------------------------------------------------------------------------------------------
                                    PM2.5      NOX       SO2       VOC      PM2.5      NOX       SO2       VOC      PM2.5      NOX       SO2       VOC
--------------------------------------------------------------------------------------------------------------------------------------------------------
Point...........................      1.05     29.44     61.43     11.36      0.02     29.98     61.82      8.12     -1.03      0.54      0.39     -3.24
Area............................     18.62     20.05      4.56     70.58     18.89     20.40      4.53     72.27      0.27      0.35     -0.03      1.69
Nonroad.........................      1.24     21.66      1.98     12.13      1.23     18.02      0.50      9.77     -0.01     -3.64     -1.48     -2.36
Onroad..........................      4.62     93.10      1.49     47.56      3.45     65.71      0.47     37.24     -1.17    -27.39     -1.02    -10.32
                                 -----------------------------------------------------------------------------------------------------------------------
    Total.......................     25.53    164.25     69.46    141.63     23.59    134.11     67.32     127.4     -1.94    -30.14     -2.14    -14.23
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Table 4 shows that the Milwaukee-Racine Area reduced direct
PM2.5, NOX, SO2, and VOC emissions by
1.94 tpwd, 30.14 tpwd, 2.14 tpwd, and 14.23 tpwd, respectively, between
2006 and 2010. Based on the information summarized above, Wisconsin has
adequately demonstrated that the improvement in air quality is due to
permanent and enforceable emissions reductions. On May 30, 2013,
Wisconsin submitted supplemental information regarding emissions of
ammonia. This information is reviewed below. Ammonia levels remain
constant from the nonattainment year to the attainment year and we do
not expect that to change during the maintenance period. However, EPA
believes that the improvement in air quality is attributable to the
PM2.5, NOX, SO2, and VOC emission
reductions described above and is not significantly affected by any
changes in ammonia emissions.
4. The Area Has a Fully Approved Maintenance Plan Pursuant to Section
175A of the CAA. (Section 107(d)(3)(E)(iv))
    In conjunction with Wisconsin's requests to redesignate the
Milwaukee-Racine Area to attainment status, Wisconsin submitted SIP
revisions to provide for maintenance of 2006 24-hour PM2.5
NAAQS in the area through 2025.
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, John 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 inventories, 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.
b. Attainment Inventory
    The Wisconsin DNR developed annual emissions inventories for
NOX, direct PM2.5, and SO2 for 2010,
one of the years the area monitored attainment of the 2006 24-hour
PM2.5 standard, as described in section IV.A.3.b.. The
attainment level of emissions is summarized in Table 4, above.
c. Demonstration of Maintenance
    Along with the redesignation requests, Wisconsin submitted
revisions to the Wisconsin PM2.5 SIP to include maintenance
plans for the Milwaukee-Racine Area, as required by section 175A of the
CAA. 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, Wisconsin's
maintenance plan submissions expressly document that the area's
emissions inventories will remain below the attainment year inventories
through 2025. In addition, for the reasons set forth below, EPA
believes that the state's submissions, in conjunction with additional
supporting information, further demonstrate that the area will continue
to maintain the PM2.5 standard at least through 2025. Thus,
if EPA finalizes its proposed approval of the redesignation requests
and maintenance plan in 2013, it is 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.
    Wisconsin's plan demonstrates maintenance of the 2006 24-hour
PM2.5 NAAQS through 2025 by showing that current and future
emissions of NOX, directly emitted PM2.5,
SO2, and VOC for the area remain at or below attainment year
emission levels. 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). As
discussed below, a comparison of current and future emissions
inventories for ammonia show relatively constant emissions, which
further support a finding that the area will continue to maintain the
standard.
    For NOX, directly emitted PM2.5,
SO2, and VOC, Wisconsin is using emissions inventory
projections for the years 2020 and 2025 to demonstrate maintenance. The
projected emissions were estimated by the WDNR, with assistance from
LADCO. As discussed in section IV.A.4.a., above, many of the control
programs that helped to bring the area into attainment of the standard
will continue to achieve additional emission reductions over the
maintenance period. These control programs include Tier 2 emission
standards for vehicles and gasoline sulfur standards, the heavy-duty
diesel engine rule, the nonroad diesel rule, and the nonroad large
spark-ignition engine and recreation engine standards. Emissions data
for all sources by source sector are shown in Tables 5 through 7,
below.

Table 5--Comparison of 2006, 2010, 2020, and 2025 NOX Emission Totals by Source Sector (tpwd) for the Milwaukee-
                                                   Racine Area
----------------------------------------------------------------------------------------------------------------
                                                                        NOX
                                  ------------------------------------------------------------------------------
              Sector                                                                                Net change
                                        2006            2010            2020            2025         2010-2025
----------------------------------------------------------------------------------------------------------------
Point............................           29.44           29.98           23.94           19.97        -10.017
Area.............................           20.05           20.40           18.20           17.87         -2.53
Nonroad..........................           21.66           18.02            7.57            5.65        -12.37
Onroad \14\......................           93.10           65.71           32.62           28.69        -37.02
                                  ------------------------------------------------------------------------------
    Total........................          164.25          134.11           82.33           72.18        -61.93
----------------------------------------------------------------------------------------------------------------

 Table 6--Comparison of 2006, 2010, 2020, and 2025 Direct PM2.5 Emission Totals by Source Sector (tpwd) for the
                                              Milwaukee-Racine Area
----------------------------------------------------------------------------------------------------------------
                                                                  Direct PM2.5
                              ----------------------------------------------------------------------------------
            Sector                                                                             Net change  2010-
                                    2006            2010            2020            2025              2025
----------------------------------------------------------------------------------------------------------------
Point \13\...................            1.05            0.02            0.32            0.44               0.42
Area.........................           18.62           18.89           17.39           17.20              -1.69
Nonroad......................            1.24            1.23            0.64            0.50              -0.73
Onroad \14\..................            4.62            3.45            2.33            2.16              -1.29
                              ----------------------------------------------------------------------------------
    Total....................           25.53           23.59           20.68           20.30              -3.29
----------------------------------------------------------------------------------------------------------------

---------------------------------------------------------------------------

    \13\ Includes Electric generating units.
    \14\ Emissions projections for the onroad sector were generated
using the MOVES model. Wisconsin submitted the MOVES based
NOX and direct PM2.5 emissions projections and
MVEBs for the onroad sector on January 17, 2013, to replace the
MOBILE6.2 based onroad emissions projections and MVEBs submitted as
part of the maintenance plan.

Table 7--Comparison of 2006, 2010, 2020, and 2025 SO2 Emission Totals by Source Sector (tpwd) for the Milwaukee-
                                                   Racine Area
----------------------------------------------------------------------------------------------------------------
                                                                        SO2
                                 -------------------------------------------------------------------------------
             Sector                                                                                Net change
                                       2006            2010            2020            2025          2010-2025
----------------------------------------------------------------------------------------------------------------
Point...........................           61.43           61.82           27.84           10.45          -51.37
Area............................            4.56            4.53            3.88            3.68           -0.85

Nonroad.........................            1.98            0.50            0.39            0.37           -0.13
Onroad \15\.....................            1.49            0.47            0.39            0.38           -0.09
                                 -------------------------------------------------------------------------------
    Total.......................           69.46           67.32           32.50           14.88          -52.44
----------------------------------------------------------------------------------------------------------------

Table 8--Comparison of 2006, 2010, 2020, and 2025 VOC Emission Totals by Source Sector (tpwd) for the Milwaukee-
                                                   Racine Area
----------------------------------------------------------------------------------------------------------------
                                                                        NOX
                                 -------------------------------------------------------------------------------
             Sector                                                                                Net change
                                       2006            2010            2020            2025          2010-2025
----------------------------------------------------------------------------------------------------------------
Point...........................           11.36            8.12           10.31           11.40            3.28
Area............................           70.58           72.27           71.70           75.05            2.78
Nonroad.........................           12.13            9.77            7.91            8.27           -1.50
Onroad \14\.....................           47.56           37.24           15.89           11.98          -25.26
                                 -------------------------------------------------------------------------------
    Total.......................          141.63          127.40          105.81          106.70          -20.70
----------------------------------------------------------------------------------------------------------------

---------------------------------------------------------------------------

    \15\ Onroad sector emissions were projected using the MOBILE6.2
emissions model.
---------------------------------------------------------------------------

    Tables 5-8 show that emissions of NOX, direct
PM2.5, SO2, and VOC, are projected to decrease by
92.07 tpwd, 2.46 tpwd, 54.58 tpwd, and 20.70 tpwd respectively, between
2010 and 2025. Furthermore, fleet turnover in onroad and nonroad
vehicles that will continue to occur after 2025 will continue to
provide additional significant emission reductions.
    In addition, as Tables 1 and 2 demonstrate, monitored
PM2.5 design value concentrations in the Milwaukee-Racine
Area are well below the NAAQS in the years beyond 2010, 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
2025 showing significant emissions reductions in direct
PM2.5, NOX, SO2, and VOC, it is very
unlikely that monitored PM2.5 values in 2025 and beyond will
show violations of the NAAQS. Additionally, the 2010-2012 design value
of 29 [mu]g/m\3\ for 24-hour standard provides a sufficient margin in
the unlikely event emissions rise slightly in the future.
    Based on the information summarized above, Wisconsin has adequately
demonstrated maintenance of the PM2.5 standard for a period
extending ten years from the date that EPA may be expected to complete
rulemaking on the state's redesignation request.
d. Maintenance Plan and Evaluation of Precursors
    With regard to the redesignation of the Milwaukee-Racine
nonattainment 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 2006
PM2.5 standard and that the state has shown that attainment
of that standard is due to permanent and enforceable emission
reductions.
    EPA finds that the state's maintenance plan shows continued
maintenance of the standard by tracking the levels of the precursors
whose control brought about attainment of the 2006 24-hour
PM2.5 standard in the Milwaukee-Racine Area, NOX,
direct PM2.5, SO2, and VOC. 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 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 Milwaukee-
Racine Area need not include any additional emission reductions of
ammonia in order to provide for continued maintenance of the standard.
    Total ammonia emissions throughout the Milwaukee-Racine Area are
very low, estimated to be less than 2,400 tons per year. See Table 9
below. This amount of ammonia emissions is small in comparison to the
total amounts of SO2, NOX, VOC, and even direct
PM2.5 emissions from sources in the area. Moreover, as
described below, available information shows that no precursor,
including ammonia, is expected to increase over the maintenance period
so as to interfere with or undermine the state's maintenance
demonstration.
    Wisconsin's maintenance plan shows that emissions of direct
PM2.5, SO2, NOX, and VOC are projected
to decrease by 5.23 tpwd, 54.58 tpwd, 92.07 tpwd, and 20.70 tpwd,
respectively, over the maintenance period. See Tables 5-8 above. In
addition, emissions inventories used in the regulatory impact analysis
(RIA) for the 2012 PM2.5 NAAQS show that ammonia emissions
are projected to decrease by 65 tpy between 2007 and 2020. See Table 9
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 2025. Given that the Milwaukee-Racine Area is already
attaining the 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 2006 24-hour 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 ammonia emissions were to increase unexpectedly between
2020 and 2025, the overall emissions reductions projected in direct
PM2.5, SO2, NOX, and VOC 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 2006 PM2.5
NAAQS during the maintenance period.

  Table 9--Comparison of 2007 and 2020 Ammonia Emission Totals by Source Sector (tpwd) for the Milwaukee-Racine
                                                    Area \16\
----------------------------------------------------------------------------------------------------------------
                                                                                Net change
                             Sector                                    2007            2020          2007-2020
----------------------------------------------------------------------------------------------------------------
Point...........................................................              33             149             116
Area............................................................           1,848           1,885              37
Nonroad.........................................................               8              10               1
Onroad..........................................................             529             309            -219
Fires...........................................................               5               5               0
                                                                 -----------------------------------------------
    Total.......................................................           2,423           2,358             -65
----------------------------------------------------------------------------------------------------------------

    In addition, available air quality modeling analyses show continued
maintenance of the standard during the maintenance period.
---------------------------------------------------------------------------

    \16\ These emissions estimates were taken from the emissions
inventories developed for the RIA for the 2012 PM2.5
NAAQS.
---------------------------------------------------------------------------

    Wisconsin modeling using Round 5 emission files from LADCO updated
``Modeled Attainment Test Software (MATS--October 2012)'' from EPA, was
completed in March, 2013. The predicted 2018 design value is 33 [mu]g/
m\3\, below the 2006 24-hour PM2.5 NAAQS. Future utility
fuel projections could be updated, likely resulting in even lower
PM2.5 design values.
    Thus, EPA believes that there is ample justification to conclude
that the Milwaukee-Racine Area should be 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 Milwaukee-Racine Area to attainment for the 2006 24-
hour PM2.5 standard.
e. Monitoring Network
    Wisconsin currently operates five monitors for purposes of
determining attainment with the 2006 24-hour PM2.5 standard
in the Milwaukee-Racine Area. Wisconsin has committed to continue to
operate and maintain these monitors and will consult with EPA prior to
making any changes to the existing monitoring network. WDNR remains
obligated to continue to quality assure monitoring data in accordance
with 40 CFR part 58 and enter all data into the AQS in accordance with
Federal guidelines.
f. Verification of Continued Attainment
    Continued attainment of the PM2.5 NAAQS in the
Milwaukee-Racine Area depends, in part, on the state's efforts toward
tracking indicators of continued attainment during the maintenance
period. Wisconsin's plan for verifying continued attainment of the 24-
hour PM2.5 standard in the Milwaukee-Racine Area consists of
continued ambient PM2.5 monitoring in accordance with the
requirements of 40 CFR part 58. Wisconsin DNR will also continue to
develop and submit periodic emission inventories as required by the
Federal Consolidated Emissions Reporting Rule (codified at 40 CFR part
51 subpart A) to track future levels of emissions.
g. 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 measures with respect to control of the pollutant(s) that
were contained in the SIP before redesignation of the area to
attainment. See section 175A(d) of the CAA.
    As required by section 175A of the CAA, Wisconsin has adopted a
contingency plan for the Milwaukee-Racine Area to address possible
future 24-hour PM2.5 air quality problems. Under Wisconsin's
plan, if a violation of the 2006 24-hour PM2.5 standard
occurs, WDNR will evaluate existing but not fully implemented,
forthcoming, and, if necessary, new control measures to correct the
violation of the standard within 18 months. Wisconsin has confirmed
EPA's interpretation that this commitment means that the measure will
be adopted and implemented within 18 months of the triggering event. In
addition, it is EPA's understanding that to acceptably address a
violation of the standard, existing and forthcoming control measures
must be in excess of emissions reductions included in the projected
maintenance inventories. Wisconsin's potential candidate contingency
measures include the following:
    i. Broaden the application of the NOX RACT program to
include a larger geographic area, and/or include sources with potential
emissions of 50 tpy, and/or increase the cost effectiveness thresholds
utilized as a basis for Wisconsin's NOX RACT Program;
    ii. Consideration of PM2.5 and SO2 RACT;
    iii. Diesel reduction emissions strategies;
    iv. Ammonia emission reduction strategies.
    EPA believes that Wisconsin's contingency plan satisfies the
pertinent requirements of section 175A(d).
h. Provisions for Future Updates of the 24-Hour PM2.5
Maintenance Plan
    As required by section 175A(b) of the CAA, Wisconsin commits to
submit to EPA an updated maintenance plan eight years after
redesignation of the

Milwaukee-Racine Area to attainment of the 2006 24-hour
PM2.5 standard to cover an additional ten-year period beyond
the initial ten year maintenance period. As required by section 175A of
the CAA, Wisconsin has committed to retain the control measures
contained in the SIP prior to redesignation, and to submit to EPA for
approval as a SIP revision, any changes to its rules or emission limits
applicable to SO2, NOX, or direct
PM2.5 sources as required for maintenance of the 2006 24-
hour PM2.5 standard in the Milwaukee-Racine Area.
    EPA has concluded that the maintenance plan adequately addresses
the five basic components of a maintenance plan: attainment inventory,
maintenance demonstration, monitoring network, verification of
continued attainment, and a contingency plan.

B. Comprehensive Emissions Inventories

    As discussed above in section IV.A.2.a.ii., section 173(c)(3) of
the CAA requires areas to submit a comprehensive, accurate and current
emissions inventory. As part of the redesignation request, Wisconsin
submitted 2006 and 2010 emissions inventories for NOX,
direct PM2.5 and SO2, and VOC. These emissions
inventories are discussed in section IV.A.3.b., above, and the data are
shown in Table 4.
    On May 30, 2013, WDNR supplemented its submittal with a 2007/2008
emissions inventory for ammonia. The additional emissions inventory
information provided by the state addresses emissions of ammonia from
the general source categories of point sources, area sources, onroad
mobile sources, and nonroad mobile sources. The state-submitted
emissions inventories were based upon information generated by LADCO in
conjunction with its member states and are presented in Table 10 below.
    LADCO ran the EMS model using data provided by the state of
Wisconsin to generate point source emissions estimates. The point
source data supplied by the state was obtained from Wisconsin's source
facility emissions reporting.
    For area sources, LADCO ran the EMS model using the 2008 National
Emissions Inventory (NEI) data provided by Wisconsin. LADCO followed
Eastern Regional Technical Advisory Committee (ERTAC) recommendations
on area sources when preparing the data. Agricultural ammonia emissions
were not taken from NEI; instead emissions were based on Carnegie
Mellon University's Ammonia Emission Inventory for the Continental
United States (CMU). Specifically, the CMU 2002 annual emissions were
grown to reflect 2007 conditions. A process-based ammonia emissions
model developed for LADCO was then used to develop temporal factors to
reflect the impact of average meteorology on livestock emissions.
    Nonroad mobile source emissions were generated using the NMIM2008
emissions model. LADCO also accounted for three other nonroad
categories not covered by the NMIM model: Commercial marine vessels,
aircraft, and railroads. Marine emissions were based on reports
prepared by Environ entitled ``LADCO Nonroad Emissions Inventory
Project for Locomotive, Commercial Marine, and Recreational Marine
Emission Sources, Final Report, December 2004'' and ``LADCO 2005
Commercial Marine Emissions, Draft, March 2, 2007.'' Aircraft emissions
were provided by Wisconsin and calculated using AP-42 emission factors
and landing and take-off data provided by the Federal Aviation
Administration. Rail emissions were based on the 2008 inventory
developed by ERTAC.
    Onroad mobile source emissions were generated using EPA's
MOVES2010a emissions model.
    EPA notes that the emissions inventory developed by LADCO is
documented in ``Regional Air Quality Analyses for Ozone,
PM2.5, and Regional Haze: Base C Emissions Inventory''
(September 12, 2011).

 Table 10--Milwaukee-Racine Area Ammonia Emissions (tpwd) for 2007/2008
                            by Source Sector
------------------------------------------------------------------------
                            Sector                              Ammonia
------------------------------------------------------------------------
Point........................................................       0.08
Area.........................................................       4.51
Nonroad......................................................       0.01
Onroad.......................................................       1.78
                                                              ----------
  Total......................................................       6.38
------------------------------------------------------------------------

    EPA has concluded that the 2007/2008 ammonia emissions inventory
provided by the state is complete and as accurate as possible given the
input data available for the relevant source categories. EPA also
believes that the inventory provides information about ammonia as a
PM2.5 precursor in the context of evaluating redesignation
of the Milwaukee-Racine Area under subpart 4. Therefore, we are
proposing to approve the ammonia emissions inventory submitted by the
state, in conjunction with the NOX, direct PM2.5,
SO2, and VOC emissions inventories, as fully meeting the
comprehensive inventory requirement of section 172(c)(3) of the CAA for
the Milwaukee-Racine Area for the 2006 24-hour PM2.5
standard.

C. Wisconsin's MVEBs

1. How are MVEBs developed?
    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
redesignations to attainment of the PM2.5 standard. These
emission control strategy SIP revisions (e.g., RFP and attainment
demonstration SIP revisions) and maintenance plans create MVEBs based
on onroad mobile source emissions for criteria pollutants and/or their
precursors to address pollution from onroad 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.
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, transportation plans and
transportation improvement programs (TIPs) must be evaluated to
determine if they conform with 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'' or approve for use in determining
transportation conformity before the MVEBs can be used. Once EPA
affirmatively approves or finds the submitted MVEBs to be adequate for
transportation conformity purposes, the MVEBs must be used by state and

Federal agencies in determining whether 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 plan, and conclude that the
SIP will achieve its overall purpose, in this case providing for
maintenance of the 2006 24-hour PM2.5 standard.
    EPA's process for determining adequacy of a MVEB consists of three
basic steps: (1) Providing public notification of a SIP submission; (2)
providing the public the opportunity to comment on the MVEB during a
public comment period; and, (3) EPA taking action on the MVEB. The
process for determining the adequacy of submitted SIP MVEBs is codified
at 40 CFR 93.118.
2. What are the MVEBs for the Milwaukee-Racine area?
    The maintenance plan submitted by Wisconsin for the Milwaukee-
Racine Area contains direct PM2.5, SO2, VOC, and
NOX MVEBs for the area for the years 2020 and 2025. The 2020
and 2025 MVEBs are set forth in Table 11 below.

                         Table 11--MVEBs for the Milwaukee-Racine Area for 2020 and 2025
----------------------------------------------------------------------------------------------------------------
                                                        NOX            PM2.5            SO2             VOC
----------------------------------------------------------------------------------------------------------------
2020............................................           32.62            2.33            0.39           15.89
2025............................................           28.69            2.16            0.38           11.98