[Federal Register Volume 80, Number 8 (Tuesday, January 13, 2015)]
[Proposed Rules]
[Pages 1815-1846]
[FR Doc No: 2015-00270]

Vol. 80

Tuesday,

No. 8

January 13, 2015

Part III

Environmental Protection Agency

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

40 CFR Parts 52 and Part 81

Approval and Promulgation of Implementation Plans; Designation of Areas
for Air Quality Planning Purposes; California; San Joaquin Valley
Moderate Area Plan and Reclassification as Serious Nonattainment for
the 2006 PM2.5 NAAQS; Proposed Rule

Federal Register / Vol. 80 , No. 8 / Tuesday, January 13, 2015 /
Proposed Rules

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

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and Part 81

[EPA-R09-OAR-2014-0636; FRL-9921-48-Region 9]

Approval and Promulgation of Implementation Plans; Designation of
Areas for Air Quality Planning Purposes; California; San Joaquin Valley
Moderate Area Plan and Reclassification as Serious Nonattainment for
the 2006 PM2.5 NAAQS

AGENCY: U.S. Environmental Protection Agency.

ACTION: Proposed rule.

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

SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve state implementation plan (SIP) revisions submitted by
California to address Clean Air Act (CAA or Act) requirements for the
2006 24-hour fine particulate matter (PM2.5) national
ambient air quality standard (NAAQS) in the San Joaquin Valley (SJV)
Moderate PM2.5 nonattainment area. These SIP revisions are
the 2012 PM2.5 Plan, submitted March 4, 2013, and the
Supplement, submitted November 6, 2014. The EPA is also proposing to
disapprove interpollutant trading ratios identified in these SIP
submittals for nonattainment new source review permitting purposes.
Finally, the EPA is proposing to reclassify the SJV area, including
Indian country within it, as a Serious nonattainment area for the 2006
PM2.5 NAAQS based on EPA's determination that the area
cannot practicably attain this standard by the applicable Moderate area
attainment date of December 31, 2015. Upon final reclassification as a
Serious area, California will be required to submit a Serious area plan
including a demonstration that the plan provides for attainment of the
2006 PM2.5 NAAQS in the SJV area by the applicable Serious
area attainment date, which is no later than December 31, 2019, or by
the most expeditious alternative date practicable, in accordance with
the requirements of part D of title I of the CAA.

DATES: Any comments must arrive by February 27, 2015.

ADDRESSES: Submit comments, identified by docket number EPA-R09-OAR-
2014-0636, by one of the following methods:
     Federal eRulemaking Portal: www.regulations.gov. Follow
the on-line instructions.
     Email<EMAIL_ADDRESS>     Mail or deliver: Wienke Tax, Office of Air Planning (AIR-
2), U.S. Environmental Protection Agency Region 9, 75 Hawthorne Street,
San Francisco, CA 94105.
    Instructions: All comments 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 Confidential Business Information (CBI) or other information
whose disclosure is restricted by statute. Information that you
consider CBI or otherwise protected should be clearly identified as
such and should not be submitted through www.regulations.gov or email.
The www.regulations.gov Web site is an ``anonymous access'' system, and
the EPA will not know your identity or contact information unless you
provide it in the body of your comment. If you send email directly to
the EPA, your email address will be automatically captured and included
as part of the public comment. If the EPA cannot read your comments due
to technical difficulties and cannot contact you for clarification, the
EPA may not be able to consider your comment.
    Docket: The index to the docket (docket number EPA-R09-OAR-2014-
0636) for this proposed rule is available electronically on the
www.regulations.gov Web site and in hard copy at EPA Region 9, 75
Hawthorne Street, San Francisco, California, 94105. While all documents
in the docket are listed in the index, some information may be publicly
available only at the hard copy location (e.g., copyrighted material),
and some may not be publicly available at either location (e.g., CBI).
To inspect the hard copy materials, please schedule an appointment
during normal business hours with the contact listed in the FOR FURTHER
INFORMATION CONTACT section below.

FOR FURTHER INFORMATION CONTACT: Wienke Tax, Air Planning Office (AIR-
2), U.S. Environmental Protection Agency, Region 9,<PHONE_NUMBER>,
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us'' and
``our'' refer to the EPA.

Table of Contents

I. Background for Proposed Actions
II. Clean Air Act Requirements for Moderate PM2.5
Nonattainment Area Plans
III. Clean Air Act Procedural Requirements for SIP Submittals
IV. Review of the San Joaquin Valley 2012 PM2.5 Plan and
Supplement
    A. Emissions Inventory
    B. Air Quality Modeling
    C. PM2.5 Precursors
    D. Reasonably Available Control Measures/Reasonably Available
Control Technology
    E. Major Stationary Source Control Requirements Under CAA
Section 189(e)
    F. Adopted Control Strategy
    G. Demonstration That Attainment by the Moderate Area Attainment
Date Is Impracticable
    H. Reasonable Further Progress and Quantitative Milestones
    I. Contingency Measures
    J. Interpollutant Trading Ratios for Nonattainment New Source
Review Permits
    K. Motor Vehicle Emission Budgets
V. Reclassification as Serious Nonattainment and Serious Area SIP
Requirements
    A. Reclassification as Serious and Applicable Attainment Date
    B. Clean Air Act Requirements for Serious PM2.5
Nonattainment Area Plans
    C. Statutory Deadline for Submittal of the Serious Area Plan
VI. Reclassification of Indian Country
VII. Summary of Proposed Actions and Request for Public Comment
VIII. Statutory and Executive Order Reviews

I. Background for Proposed Actions

    On October 17, 2006, the EPA revised the 24-hour national ambient
air quality standard (NAAQS or standard) for PM2.5,
particulate matter with a diameter of 2.5 microns or less, to provide
increased protection of public health by lowering its level from 65
micrograms per cubic meter ([mu]g/m\3\) to 35 [mu]g/m\3\ (40 CFR
50.13).\1\ Epidemiological studies have shown statistically significant
correlations between elevated PM2.5 levels and premature
mortality. Other important health effects associated with
PM2.5 exposure include aggravation of respiratory and
cardiovascular disease (as indicated by increased hospital admissions,
emergency room visits, absences from school or work, and restricted
activity days), changes in lung function and increased respiratory
symptoms. Individuals particularly sensitive to PM2.5
exposure include older adults, people with heart and lung disease, and
children (78 FR 3086 at 3088, January 15, 2013). PM2.5 can
be emitted directly into the atmosphere as a solid or liquid particle
(``primary PM2.5'' or ``direct PM2.5'') or can be
formed in the atmosphere as a result of

various chemical reactions among precursor pollutants such as nitrogen
oxides, sulfur oxides, volatile organic compounds, and ammonia
(``secondary PM2.5'').\2\
---------------------------------------------------------------------------

    \1\ See 71 FR 61224 (October 17, 2006). The EPA set the first
NAAQS for PM2.5 on July 18, 1997 (62 FR 36852), including
annual standards of 15.0 [mu]g/m\3\ based on a 3-year average of
annual mean PM2.5 concentrations and 24-hour (daily)
standards of 65 [mu]g/m\3\ based on a 3-year average of 98th
percentile 24-hour concentrations (40 CFR 50.7). In 2012, the EPA
revised the annual standard to lower its level to 12 [mu]g/m\3\ (78
FR 3086, January 15, 2013, codified at 40 CFR 50.18). Unless
otherwise noted, all references to the PM2.5 standard in
this notice are to the 2006 24-hour standard of 35 [mu]g/m\3\
codified at 40 CFR 50.13.
    \2\ See EPA, Regulatory Impact Analysis for the Final Revisions
to the National Ambient Air Quality Standards for Particulate Matter
(EPA-452/R-12-005, December 2012), p. 2-1.
---------------------------------------------------------------------------

    Following promulgation of a new or revised NAAQS, the EPA is
required by CAA section 107(d) to designate areas throughout the nation
as attaining or not attaining the NAAQS. On November 13, 2009, the EPA
designated the SJV as nonattainment for the 2006 PM2.5
standard of 35 [mu]g/m\3\ (74 FR 58688, November 13, 2009). This
designation became effective on December 14, 2009 (40 CFR 81.305). The
SJV area is also designated nonattainment for the 1997 annual and 24-
hour PM2.5 standards.\3\
---------------------------------------------------------------------------

    \3\ See 70 FR 944 (January 5, 2005) and 40 CFR 81.305. In June
2008, California submitted the 2008 PM2.5 Plan to provide
for attainment of the 1997 PM2.5 standards in the SJV. In
November 2011, the EPA approved all but the contingency measures in
the 2008 PM2.5 Plan (76 FR 69896, November 9, 2011). In
July 2013, the State submitted a revised contingency measure plan,
which the EPA approved in May 2014 (79 FR 29327, May 22, 2014).
---------------------------------------------------------------------------

    The SJV PM2.5 nonattainment area is home to 4 million
people and is the nation's leading agricultural region. Stretching over
250 miles from north to south, it is partially enclosed by the Coast
Mountain range to the west, the Tehachapi Mountains to the south, and
the Sierra Nevada range to the east. It encompasses over 23,000 square
miles and includes all or part of eight counties: San Joaquin,
Stanislaus, Merced, Madera, Fresno, Tulare, Kings, and the valley
portion of Kern. For a precise description of the geographic boundaries
of the San Joaquin Valley PM2.5 nonattainment area, see 40
CFR 81.305.
    The local air district with primary responsibility for developing
plans to attain the NAAQS in the area is the San Joaquin Valley Air
Pollution Control District (SJVAPCD or District). The District works
cooperatively with the California Air Resources Board (CARB) in
preparing these plans. Authority for regulating sources under state
jurisdiction in the SJV is split between the District, which has
responsibility for regulating stationary and most area sources, and
CARB, which has responsibility for regulating most mobile sources.
    Ambient 24-hour PM2.5 NAAQS design value levels in the
San Joaquin Valley are among the highest recorded in the United States
for the 2011-2013 period.\4\ Exceedances of the 24-hour
PM2.5 standard occur almost exclusively during the late fall
and winter months from October to March, when ambient PM2.5
is dominated by ammonium nitrate (a secondary particulate formed from
nitrogen oxides (NOX) and ammonia emissions) and directly-
emitted particulates, such as wood smoke. During the winter, the SJV
experiences extended periods of stagnant weather with cold foggy
conditions which encourage wood burning and are conducive to the
formation of ammonium nitrate (2012 PM2.5, Appendix G, pp. 7
to 9).
---------------------------------------------------------------------------

    \4\ See U.S. EPA, 2013 Design Value Reports, PM2.5
Detailed Information Updated 8/24/14, available at http://www.epa.gov/airtrends/values.html
(``PM2.5_DesignValues_20112013_FINAL_08_28_14'')
(hereafter ``2013 PM2.5 Design Value Reports''). ``Design
values'' are the 3-year average NAAQS metrics that are compared to
the NAAQS levels to determine when a monitoring site meets or does
not meet the NAAQS. See 40 CFR part 50 Appendix N, Section 1.0(c).
---------------------------------------------------------------------------

II. Clean Air Act Requirements for PM2.5 Moderate
Nonattainment Area Plans

    In April 2007, the EPA issued the Clean Air Fine Particle
Implementation Rule (``2007 PM2.5 Implementation Rule'') to
assist states with the development of SIPs to meet the Act's attainment
planning requirements for the 1997 PM2.5 standards (72 FR
20583, April 25, 2007, codified at 40 CFR part 51, subpart Z). This
rule was premised on the EPA's prior interpretation of the Act as
allowing for implementation of the PM2.5 NAAQS solely
pursuant to the general nonattainment area provisions in subpart 1 of
part D, title I of the CAA (``subpart 1'') and not the more specific
provisions for particulate matter nonattainment areas in subpart 4 of
part D, title I of the Act (``subpart 4''). Among other things, the
2007 PM2.5 Implementation Rule included nationally
applicable presumptions regarding the need to evaluate and potentially
control emissions of certain PM2.5 precursors.\5\
---------------------------------------------------------------------------

    \5\ Specifically, in 40 CFR 51.1002(c), the 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,'' unless the State or the EPA provided an
appropriate technical demonstration showing that emissions from
sources of these pollutants ``significantly contribute'' to
PM2.5 concentrations in the nonattainment area (40 CFR
51.1002(c)(3), (4) and 72 FR 20586 at 20589-97 (April 25, 2007)).
---------------------------------------------------------------------------

    In March 2012, the EPA issued a guidance document to aid states in
preparing SIPs to meet the Act's attainment planning requirements for
the 2006 24-hour PM2.5 standard.\6\ The 2012 guidance was
based, in large part, on the requirements in the 2007 PM2.5
Implementation Rule, which the EPA based solely upon the statutory
requirements of subpart 1.
---------------------------------------------------------------------------

    \6\ See Memorandum, dated March 2, 2012 (withdrawn June 6,
2013), from Stephen D. Page, Director, Office of Air Quality
Planning and Standards, to EPA Regional Air Directors, Regions I-X
re: ``Implementation Guidance for the 2006 24-Hour Fine Particle
(PM2.5) National Ambient Air Quality Standards (NAAQS)''
(``2012 Guidance'') Available at: http://epa.gov/ttn/naaqs/pm/pm25_guide.html.
---------------------------------------------------------------------------

    California had three years from the effective date of SJV's
designation as nonattainment for the 2006 PM2.5 standard to
submit a SIP for the SJV that addressed the applicable requirements of
the Act.\7\ On December 20, 2012, the District adopted the 2012
PM2.5 Plan to provide for attainment of the 2006
PM2.5 standard. On January 24, 2013, CARB adopted the Plan
as an element of the California SIP and submitted it to the EPA on
March 4, 2013.
---------------------------------------------------------------------------

    \7\ See CAA section 172(b) and 40 CFR 51.1002(a).
---------------------------------------------------------------------------

    On January 4, 2013, several weeks after the District's adoption of
the Plan, the U.S. Court of Appeals for the DC Circuit issued its
decision in a challenge to the EPA's 2007 mPM2.5
Implementation Rule (NRDC v. EPA, 706 F.3d 428 (D.C. Cir. 2013)). In
NRDC, the court held that the EPA erred in implementing the 1997
PM2.5 standards solely pursuant to the general
implementation requirements of subpart 1, without also considering the
requirements specific to particulate matter nonattainment areas in
subpart 4.\8\ The court reasoned that the plain meaning of the CAA
requires implementation of the 1997 PM2.5 standards under
subpart 4 because PM2.5 particles fall within the statutory
definition of PM10 and are thus subject to the same
statutory requirements as PM10. The court remanded the 2007
PM2.5 Implementation Rule in its entirety, including the
presumptions concerning VOC and ammonia in 40 CFR 51.1002, and
instructed the EPA ``to repromulgate these rules pursuant to Subpart 4
consistent with this opinion.''
---------------------------------------------------------------------------

    \8\ The NRDC decision also remanded the EPA's 2008 final rule to
implement the nonattainment New Source Review (NNSR) permitting
requirements for PM2.5 (73 FR 28231, May 16, 2008) which,
like the 2007 PM2.5 Implementation Rule, was premised on
the requirements of subpart 1. Today's proposal does not address
requirements for NNSR programs other than the requirements
concerning PM2.5 precursors in CAA section 189(e), which
we discuss in Section IV.C below, and PM2.5
interpollutant trading ratios, which we discuss in Section IV.J
below.
---------------------------------------------------------------------------

    Consistent with the NRDC decision, on June 2, 2014 (79 FR 31566),
the EPA published a final rule classifying all areas currently
designated nonattainment for the 1997 and/or 2006 PM2.5
standards as ``Moderate'' under subpart 4 and establishing a deadline
of December 31, 2014 for states to submit

any attainment-related and nonattainment new source review (NNSR) SIP
elements required for these areas pursuant to subpart 4. The EPA
provided its rationale for these actions in both the proposed and final
classification/deadline rule.\9\
---------------------------------------------------------------------------

    \9\ See 79 FR 69806, 69809 (November 21, 2013) and 79 FR 31566,
31568 (June 2, 2014).
---------------------------------------------------------------------------

    On September 18, 2014, the District adopted the ``Supplemental
Document, Clean Air Act Subpart 4: The 2012 PM2.5 Plan for
the 2006 PM2.5 Standard and District Rule 2201 (New and
Modified Stationary Source Review)'' (``Supplement'') as a revision to
the 2012 PM2.5 Plan. The District adopted the Supplement to
address subpart 4 requirements for the 2006 PM2.5 standard
to the extent that these requirements were not adequately addressed in
the 2012 PM2.5 Plan. CARB submitted the Supplement to the
EPA on November 6, 2014. The Supplement includes information on the
implementation of reasonably available controls for ammonia sources in
the SJV and the District's demonstration that attainment by the
Moderate area attainment date of December 31, 2015 is impracticable
(``impracticability demonstration''). As a consequence of the NRDC
decision, we are reviewing the 2012 PM2.5 Plan and
Supplement for compliance with the applicable requirements of both
subpart 1 and subpart 4.
    The EPA has longstanding guidance interpreting the subpart 4
requirements for particulate matter nonattainment areas (see ``State
Implementation Plans; General Preamble for the Implementation of Title
I of the Clean Air Act Amendments of 1990'' (57 FR 13498, April 16,
1992) (``General Preamble'') and ``State Implementation Plans for
Serious PM-10 Nonattainment Areas, and Attainment Date Waivers for PM-
10 Nonattainment Areas Generally; Addendum to the General Preamble for
the Implementation of Title I of the Clean Air Act Amendments of 1990''
(59 FR 41998, August 16, 1994) (``Addendum'')). The General Preamble at
13538 discusses the relationship of subpart 1 and subpart 4 SIP
requirements, and notes that SIPs for moderate nonattainment areas must
meet the general provisions in subpart 1 to the extent that these
provisions are not otherwise ``subsumed by, or integrally related to,
the more specific [subpart 4] requirements.'' Some subpart 1 provisions
have no subpart 4 equivalent (e.g., the emission inventories (CAA
section 172(c)(3)) and contingency measures (CAA section 172(c)(9)) and
for these provisions, subpart 1 continues to govern. Other provisions
of subpart 1 are subsumed or superseded by more specific requirements
in subpart 4 (e.g., certain provisions concerning attainment dates).
    Because the 2012 PM2.5 Plan was initially developed and
submitted to meet the requirements of subpart 1 and the 2007
PM2.5 Implementation Rule, certain elements of the Plan
address provisions of subpart 1 rather than the applicable provisions
of subpart 4. Specifically, these elements are the State's request for
an attainment date extension from 2014 to 2019 under CAA section
172(a)(2)(A); the demonstration of attainment by 2019; those portions
of the reasonably available control measure (RACM) demonstration that
show there are no section 172(c)(1) RACM that would expedite attainment
from 2019 to 2018; the transportation conformity motor vehicle emission
budgets for 2019; and the contingency measures for failure to attain.
We are not proposing any action on these specific SIP elements at this
time.
    As part of this proposal, the EPA is proposing to determine that
the SJV cannot practicably attain the 2006 PM2.5 standard by
the Moderate area attainment date of December 31, 2015 and to
reclassify the area from Moderate to Serious nonattainment under
subpart 4. Should the EPA finalize this proposal to reclassify the SJV
area as a Serious area, the State will be required to adopt and submit
a new plan addressing the Serious area requirements in subpart 4. We
discuss these Serious area requirements in more detail in section V.
below.

III. Clean Air Act Procedural Requirements for SIP Submittals

    We are proposing action on two California SIP submittals. The first
is the ``2012 PM2.5 Plan,'' which the State submitted to EPA
on March 4, 2013 (hereafter ``2012 PM2.5 Plan'' or ``the
Plan'') \10\ and the second is the ``Supplemental Document, Clean Air
Act Subpart 4: The 2012 PM2.5 Plan for the 2006
PM2.5 Standard and District Rule 2201 (New and Modified
Stationary Sources),'' which the State submitted to EPA on November 6,
2014 (hereafter ``the Supplement'').\11\
---------------------------------------------------------------------------

    \10\ See Letter dated March 4, 2013, from James N. Goldstene,
Executive Officer, California Air Resources Board, to Jared
Blumenfeld, Regional Administrator, EPA Region 9, with enclosures.
    \11\ See Letter dated November 6, 2014, from James N. Goldstene,
Executive Officer, California Air Resources Board, to Jared
Blumenfeld, Regional Administrator, EPA Region 9, with enclosures.
---------------------------------------------------------------------------

    CAA sections 110(a)(1) and (2) and 110(l) require each state to
provide reasonable public notice and opportunity for public hearing
prior to the adoption and submittal of a SIP or SIP revision. To meet
this requirement, every SIP submittal should include evidence that
adequate public notice was given and an opportunity for a public
hearing was provided consistent with the EPA's implementing regulations
in 40 CFR 51.102.
    Both the District and CARB satisfied applicable statutory and
regulatory requirements for reasonable public notice and hearing prior
to adoption and submittal of the 2012 PM2.5 Plan. The
District conducted public workshops, provided public comment periods,
and held a public hearing prior to the adoption of the Plan on December
20, 2012.\12\ CARB provided the required public notice and opportunity
for public comment prior to its January 24, 2013 public hearing on the
Plan.\13\ The SIP submittal includes proof of publication of notices
for these public hearings. We find, therefore, that the 2012
PM2.5 Plan meets the procedural requirements for public
notice and hearing in CAA sections 110(a) and 110(l).
---------------------------------------------------------------------------

    \12\ See 2012 PM2.5 Plan, p. ES-6 and SJVAPCD
Governing Board Resolution 2012-12-19, ``In the Matter of Adopting
the San Joaquin Valley Unified Air Pollution Control District 2012
PM2.5 Plan,'' December 20, 2012.
    \13\ See CARB Resolution 13-2, ``San Joaquin Valley
PM2.5 State Implementation Plan,'' January 24, 2013.
---------------------------------------------------------------------------

    The District adopted the Supplement after reasonable public notice
and hearing.\14\ CARB adopted the Supplement for submittal as a SIP
revision at its October 24, 2014 Board meeting after reasonable public
notice.\15\
---------------------------------------------------------------------------

    \14\ See Notice of Public Hearing to Adopt Supplemental Document
to the 2012 PM2.5 Plan for the 2006 PM2.5 Standard and New Source
Review Rule to address Clean Air Act Subpart 4 requirements,
available at http://www.valleyair.org/Air_Quality_Plans/docs/NPH_SD_PM25Plan_09_2014.pdf.
    \15\ See CARB, Notice of Public Meeting to Consider the
Supplemental Document for the San Joaquin Valley 24-Hour
PM2.5 SIP, September 23, 2014, and CARB Board Resolution
14-37, October 24, 2014.
---------------------------------------------------------------------------

    CAA section 110(k)(1)(B) requires the EPA to determine whether a
SIP submittal is complete within 60 days of receipt. This section also
provides that any plan that the EPA has not affirmatively determined to
be complete or incomplete will become complete by operation of law six
months after the date of submittal. The EPA's SIP completeness criteria
are found in 40 CFR part 51, Appendix V.
    The March 4, 2013 submittal of the 2012 PM2.5 Plan
became complete by operation of law on September 4, 2014. We find that
the Supplement satisfies the completeness criteria in 40 CFR part

51, appendix V (see our Technical Support Document at section I.B).

IV. Review of the San Joaquin Valley 2012 PM2.5 Plan and
Supplement

    We summarize our evaluation of the 2012 PM2.5 Plan and
Supplement below. Our detailed evaluation can be found in the Technical
Support Document (TSD) for this proposal which is available online at
www.regulations.gov in docket number EPA-R09-OAR-2014-0636, on EPA
Region 9's Web site at www.epa.gov/region9/air/sjv-pm25/index.html, or
from the EPA contact listed at the beginning of this notice.

A. Emissions Inventory

1. Requirements for Emissions Inventories
    CAA section 172(c)(3) requires that each SIP include a
``comprehensive, accurate, current inventory of actual emissions from
all sources of the relevant pollutant or pollutants in [the] area. . .
.'' By requiring an accounting of actual emissions from all sources of
the relevant pollutants in the area, this section provides for the base
year inventory to include all emissions that contribute to the
formation of a particular NAAQS pollutant. For the 2006 24-hour
PM2.5 standard, this includes direct PM2.5 as
well as the main chemical precursors to the formation of secondary
PM2.5: NOX, SO2, VOC, and ammonia
(NH3). Primary PM2.5 includes condensable and
filterable particulate matter.
    A state should include in its SIP submittal documentation
explaining how the emissions data were calculated. In estimating mobile
source emissions, a state should use the latest emissions models and
planning assumptions available at the time the SIP is developed.
California is required to use EMFAC2011 to estimate tailpipe and brake
and tire wear emissions of PM2.5, NOX,
SO2, and VOC from on-road mobile sources (78 FR 14533, March
6, 2013). States are required to use the EPA's AP-42 road dust method
for calculating re-entrained road dust emissions from paved roads (76
FR 6328, February 4, 2011).
    In addition to the base year inventory submitted to meet the
requirements of CAA section 172(c)(3), the state must also submit
future ``baseline inventories'' for the projected attainment year and
each reasonable further progress (RFP) milestone year, and any other
year of significance for meeting applicable CAA requirements. By
``baseline inventories'' (also referred to as ``projected baseline
inventories''), we mean projected emissions inventories for future
years that account for, among other things, the ongoing effects of
economic growth and adopted emissions control requirements. The SIP
should include documentation explaining how the emissions projections
were calculated.
2. Emissions Inventories in the 2012 PM2.5 Plan
    The planning inventories for direct PM2.5 and all
PM2.5 precursors (NOX, SO2, VOC, and
ammonia) for the SJV PM2.5 nonattainment area together with
documentation for the inventories are found in Appendix B of the 2012
PM2.5 Plan. Winter daily average inventories, representing
conditions in the period November through April, are provided for the
base year 2007 and the baseline year of 2012 and each baseline year
from 2014 to 2019. A winter inventory is used because exceedances of
the 35 [mu]g/m\3\ PM2.5 standard in the SJV occur mostly
during the winter months (p. 3-4 and Appendix G, p. G-6). Baseline
inventories reflect all control measures adopted prior to January 2012.
Growth factors used to project these baseline inventories are derived
from data obtained from a number of sources such as the California
Energy Commission and Department of Finance as well as studies
commissioned by the SJV's metropolitan planning organizations (pp. B-21
to B-30).
    Each inventory includes emissions from point, area, on-road, and
non-road sources. The inventories use EMFAC2011 for estimating on-road
motor vehicle emissions (p. B-26). After EMFAC2011 was released in
2011, new information on statewide diesel fuel usage and economic
forecasts became available to the State. For the 2012 PM2.5
Plan, CARB adjusted EMFAC2011 emissions estimates for heavy-duty trucks
to reflect this new information (p. B-26). The EPA allowed the use of
these adjustment factors in transportation conformity determinations in
the SJV.\16\ Re-entrained paved road dust emissions were calculated
using the EPA's AP-42 road dust methodology (Appendix B, p. B-25).
---------------------------------------------------------------------------

    \16\ Letter dated January 14, 2014, Matthew Lakin, Chief, Air
Planning Office, EPA-Region 9 to John Taylor, Branch Chief,
Transportation Planning Branch, CARB; Subject: Use of San Joaquin
Valley Heavy Duty Diesel Vehicle Recession Adjustment Methodology.
---------------------------------------------------------------------------

    Table 1 provides a summary of the winter daily average inventories
of direct PM2.5 and PM2.5 precursors for the base
year of 2007. These inventories provide the basis for the control
measure analysis and the RFP and attainment demonstrations in the 2012
PM2.5 Plan.

   Table 1--San Joaquin Valley Emissions Inventory Summary for Direct PM[ihel2].[ihel5] and PM[ihel2].[ihel5]
                                        Precursors for the 2007 Base Year
                                         [Winter daily average in tons]
----------------------------------------------------------------------------------------------------------------
                                     Direct
                               PM[ihel2].[ihel5]        NOX          SO[ihel2]          VOC           Ammonia
----------------------------------------------------------------------------------------------------------------
Stationary Sources...........               9.4             45.6            10.4            96.2            19.8
Area Sources.................              62.5             19.0             0.8           213.2           342.2
On-Road Mobile Sources.......               9.1            296.5             0.6            67.3             5.3
Off-Road Mobile Sources......               6.1            103.9             1.0            38.0             0.0
                              ----------------------------------------------------------------------------------
    Total....................              87.1            465.1            12.8           414.8           367.3
----------------------------------------------------------------------------------------------------------------
Source: 2012 PM[ihel2].[ihel5] Plan, Appendix B, Tables B-1 to B-5.

3. Evaluation and Proposed Action
    The inventories in the 2012 PM2.5 Plan are based on the
most current and accurate information available to the State and
District at the time the Plan and its inventories were being developed
in 2011 and 2012, including the latest EPA-approved version of
California's mobile source emissions model, EMFAC2011. The inventories
comprehensively address all source categories in the SJV and were
developed consistent with the EPA's inventory guidance. For these
reasons, we are proposing to approve the 2007 base year emissions
inventory in the 2012 PM2.5 Plan as meeting the requirements
of CAA section 172(c)(3).

We are also proposing to find that the baseline inventories in the Plan
provide an adequate basis for the RACM, RFP, and impracticability
demonstrations.

B. Air Quality Modeling

1. Requirements for Air Quality Modeling
    CAA section 189(a)(1)(B) requires each state in which a Moderate
area is located to submit a plan that includes a demonstration either
(i) that the plan will provide for attainment by the applicable
attainment date, or (ii) that attainment by that date is impracticable.
The 2012 PM2.5 Plan and Supplement include a demonstration
that attainment by the Moderate area attainment date is impracticable.
    Air quality modeling is used to establish emissions attainment
targets, the combination of emissions of PM2.5 and
PM2.5 precursors that the area can accommodate and still
attain the standard, and to assess whether the proposed control
strategy will result in attainment of the standard. Air quality
modeling is performed for a base year and compared to air quality
monitoring data collected during that year in order to determine model
performance. Once the model performance is determined to be acceptable,
future year changes to the emissions inventory are simulated with the
model to determine the relationship between emissions reductions and
changes in ambient air quality. To project future design values, the
model response to emission reductions, in the form of Relative Response
Factors (RRFs), is applied to monitored design values from the base
year.
    For demonstrating attainment, the EPA's recommendations for model
input preparation, model performance evaluation, use of the model
output for the attainment demonstration, and modeling documentation are
described in Guidance on the Use of Models and Other Analyses for
Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5, and
Regional Haze, EPA-454/B-07-002, April 2007 (``Modeling Guidance''), as
amended by ``Update to the 24 Hour PM2.5 NAAQS Modeled
Attainment Test,'' Memorandum dated June 28, 2011, from Tyler Fox, Air
Quality Modeling Group, OAQPS, EPA to Regional Air Program Managers,
EPA (``Modeling Guidance Update'').\17\ The EPA has not issued modeling
guidance specific to impracticability demonstrations but believes that
a state seeking to make such a demonstration generally should provide
air quality modeling similar to that required for an attainment
demonstration. The main difference is that for an impracticability
demonstration, the model's projected design value on the required
attainment date would be above the NAAQS, despite full implementation
of the SIP control strategy including all reasonably available control
measures (RACM). Alternatively, a model projection could show that the
implementation of the SIP control strategy (including RACM) results in
attainment of the standard, but that this is achieved only after the
applicable attainment date. We are using the latter alternative in
evaluating the 2012 PM2.5 Plan, since its modeling focuses
on an attainment year of 2019, instead of 2015, which is the Moderate
area attainment year for this area under subpart 4 (CAA
section188(c)(1)).\18\
---------------------------------------------------------------------------

    \17\ The EPA Modeling Guidance and Modeling Guidance Update are
available on EPA's SCRAM Web site, Web page: http://www.epa.gov/scram001/guidance_sip.htm; direct links: http://www.epa.gov/scram001/guidance/guide/final-03-pm-rh-guidance.pdf and http://www.epa.gov/ttn/scram/guidance/guide/Update_to_the_24-hour_PM25_Modeled_Attainment_Test.pdf.
    \18\ The District developed the Plan to address the requirements
of subpart 1 as interpreted in the 2007 p.m.2.5 Implementation Rule
(prior to the D.C. Circuit's remand of this rule in NRDC) which
authorized the EPA to extend the attainment date as appropriate for
a period no greater than 10 years from the date of designation,
considering the severity of nonattainment and the availability and
feasibility of pollution control measures (see CAA section
172(a)(2)(A) and 40 CFR 51.1004). Because the SJV areas was
designated nonattainment effective December 14, 2009 (74 FR 58688
(November 13, 2009), the date ``10 years from the date of
designation'' would be December 14, 2019.
---------------------------------------------------------------------------

    The EPA recommends that states prepare modeling protocols as part
of their modeled attainment demonstrations (Guidance, p. 133). The
Guidance (at pp. 133-134) describes the topics to be addressed in this
modeling protocol. A modeling protocol should detail and formalize the
procedures for conducting all phases of the modeling analysis, such as
describing the background and objectives, creating a schedule and
organizational structure, developing the input data, conducting model
performance evaluations, interpreting modeling results, describing
procedures for using the model to demonstrate whether proposed
strategies are sufficient to attain the applicable standard, and
producing documentation to be submitted for EPA Regional Office review
and approval prior to actual modeling.
    In addition to a modeled attainment demonstration, which focuses on
locations with an air quality monitor, EPA's Guidance describes an
Unmonitored Area Analysis (UAA). This analysis is intended to ensure
that a control strategy leads to reductions in PM2.5 at
other locations that have no monitor but that might have base year and
future baseline (projection year) ambient PM2.5 levels
exceeding the standard.
    Finally, as discussed below, the Modeling Guidance recommends
supplemental air quality analyses. These may be used as part of a
Weight of Evidence analysis (WOEA), which assesses attainment by
considering evidence other than the main air quality modeling
attainment test. While supplemental analyses can increase confidence in
the reliability of the modeling, they are less important for evaluating
the impracticability demonstration per se. That is, the level of rigor
in the modeling analyses supporting the Plan's conclusion that
attainment will occur by 2019 is less important when the object is to
demonstrate that attainment is not practicable by 2015. Supplemental
analyses to support a demonstration of attainment by the end of 2019
will be necessary in a new Serious area plan.
2. Air Quality Modeling in the 2012 PM2.5 Plan
    A brief description of the modeling in 2012 PM2.5 Plan
and our evaluation of it follows. More detailed information about the
modeling is available in section II.B. of the TSD.
    CARB and the District jointly performed the air quality modeling
for the 2012 PM2.5 Plan. The modeling analysis uses the
Community Multiscale Air Quality (CMAQ) photochemical model, developed
by the EPA.\19\ It incorporates routinely available meteorological and
air quality data collected during 2007. The MM5 (Mesoscale Model
version 5) was used to prepare meteorological input for CMAQ. Air
Quality modeling was performed only for the first and fourth quarters
(Q1 and Q4) of 2007 which is sufficient for modeling the 2006 24-hour
PM2.5 standard in the SJV because the high 24-hour
PM2.5 concentrations occur only during the colder part of
the year. Only the top 10 percent of modeled days is required for
projecting the 98th percentile-based design values into the future.
(Modeling Guidance Update, p. B-1) The 2012 PM2.5 Plan's
modeling protocol is contained in Appendix F and includes descriptions
of the photochemical modeling. Additional

description of the photochemical modeling is also covered in the Weight
of Evidence Analysis (''WOEA'').\20\ The protocol was reviewed by the
EPA and a number of academic experts, and covers all of the topics
recommended in the Guidance, including thorough discussions of past
modeling results and emission inventory preparation procedures.
---------------------------------------------------------------------------

    \19\ The 2012 PM2.5 Plan also included receptor
modeling source apportionment analyses, using both the Chemical Mass
Balance (CMB) model and the Positive Matrix Factorization (PMF)
model. These models distinguish the ambient PM2.5
contributions of several broad emissions source categories based on
how they match the chemical species components of PM2.5
measurements. These results generally corroborated results from the
photochemical modeling, but were not themselves part of the
attainment demonstration.
    \20\ The WOEA is Appendix B to the ``[CARB] Staff Report,
Proposed Revision to the PM2.5 State Implementation Plan
(SIP) for the San Joaquin Valley,'' Release Date: January 11, 2013
(``Staff Report''), which can be found in the docket for this
proposed rule. Appendix G to the 2012 PM2.5 Plan also
contains a weight of evidence analysis which is identical to the one
in the CARB Staff Report except for the two additional appendices 5
and 6.
---------------------------------------------------------------------------

    The air quality modeling and results are summarized in Chapter 4 of
the Plan (section 4.5, p. 4-22) and in the WOEA (section 10, p. 62).
The Plan's meteorological model and air quality model performance
statistics and graphics are available from the CARB Web site
(``Meteorology and Air Quality Modeling for the 2012 24-Hour
PM2.5 Plan for the San Joaquin Valley'', http://arb.ca.gov/eos/SIP_Modeling_PM25/24hr_PM25_ModelingPage.htm). The air quality
model performance appears to be quite good, with bias within the
criteria for acceptance, and usually within the original performance
goals; performance is very good for total PM2.5 and for
nitrate, the largest component of PM2.5; however, time
series plots show that some high PM2.5 periods were
underestimated.
    The 2012 PM2.5 Plan included a UAA in Appendix 6 of the
Weight of Evidence Analysis in Appendix G of the Plan (p. G-175). (ARB
Staff Report Appendix B is identical to Plan Appendix G, except that it
does not include the latter's Appendices 5 and 6).
3. Evaluation of the Air Quality Modeling in the 2012 PM2.5
Plan
    The modeling showed that existing State and District control
measures are not sufficient to attain the 2006 PM2.5
standard by 2019 at all monitoring sites in the SJV. Modeling of the
additional measures in the Plan (additional direct PM2.5
reductions from residential wood burning and from commercial
charbroiling) showed attainment at all sites by 2019. Id.
    Given the extensive discussion of modeling procedures, tests, and
performance analyses called for in the Modeling Protocol and the good
model performance, the EPA finds that the modeling is adequate for
purposes of supporting the RACM demonstration, the RFP demonstration,
and the demonstration of impracticability in the 2012 PM2.5
Plan and Supplement. To satisfy the statutory requirements for a
serious area attainment demonstration, however, the State will need to
address documentation gaps outlined in the TSD (section II.B. of the
TSD).
    While the State included a UAA in the Plan, it makes no difference
for the impracticability demonstration we are concerned with here. Any
unmonitored peaks with concentrations higher than at the monitors would
merely strengthen the case for attainment being impracticable by the
required date. A demonstration that attainment is impracticable at
monitor locations is sufficient to meet the requirements of section
189(a)(1)(B)(ii). The EPA finds that the supplemental analyses
presented in the WOEA are useful in a weight of evidence analysis, and
support the demonstration of the impracticability of attainment by
2015.
    We note finally that existing ambient air quality monitoring data
also support the modeled demonstration that attainment of the 2006
PM2.5 standard by December 31, 2015 is impracticable.
Compliance with the 2006 24-hour PM2.5 standard is assessed
using the three-year average of the yearly 98th percentile
concentrations. The most recent monitored PM2.5
concentrations show that compliance with the 2006 standard is not
possible by the end of 2015. See discussion in section II.F.3 of the
TSD and section V.A. of this proposal.

C. PM2.5 Precursors

1. Requirements for the Control of PM2.5 Precursors
    The composition of PM2.5 is complex and highly variable
due in part to the large contribution of secondary PM2.5 to
total fine particle mass in most locations, and to the complexity of
secondary particle formation processes. A large number of possible
chemical reactions, often non-linear in nature, can convert gaseous
SO2, NOX, VOC and ammonia to PM2.5,
making them precursors to PM2.5.\21\ Formation of secondary
PM2.5 may also depend on atmospheric conditions, including
solar radiation, temperature, and relative humidity, and the
interactions of precursors with preexisting particles and with cloud or
fog droplets.\22\
---------------------------------------------------------------------------

    \21\ EPA, Air Quality Criteria for Particulate Matter (EPA/600/
P-99/002aF, October 2004), Chapter 3.
    \22\ EPA, Regulatory Impact Analysis for the Final Revisions to
the National Ambient Air Quality Standards for Particulate Matter
(EPA-452/R-12-005, December 2012), p. 2-1.
---------------------------------------------------------------------------

    The 2007 PM2.5 Implementation Rule contained rebuttable
presumptions concerning the four PM2.5 precursors applicable
to attainment plans and control measures related to those plans. See 40
CFR 51.1002(c). Although the rule included presumptions that states
should address SO2 and NOx emissions in their attainment
plans, it also included presumptions that regulation of VOCs and
ammonia was not necessary. Specifically, in 40 CFR 51.1002(c), the 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,'' unless the state or the EPA provided
an appropriate technical demonstration showing that emissions from
sources of these pollutants ``significantly contribute'' to
PM2.5 concentrations in the nonattainment area. 40 CFR
51.1002(c)(3), (4); see also 2007 p.m.2.5 Implementation Rule, 72 FR
20586 at 20589-97 (April 25, 2007).
    In NRDC, however, the D.C. Circuit remanded the EPA's 2007
PM2.5 Implementation Rule in its entirety, including the
presumptions concerning VOC and ammonia in 40 CFR 51.1002. See NRDC v.
EPA, 706 F.3d 428 (D.C. Cir. 2013). Although the court expressly
declined to decide the specific challenge to these presumptions (see
706 F.3d at 437, n. 10 (D.C. Cir. 2013)), the court cited CAA section
189(e) \23\ to support its observation that ``[a]mmonia is a precursor
to fine particulate matter, making it a precursor to both
PM2.5 and PM10'' and that ``[f]or a
PM10 nonattainment area governed by subpart 4, a precursor
is presumptively regulated.'' 706 F.3d at 436, n. 7 (citing CAA section
189(e)). Consistent with the NRDC decision, EPA now interprets the Act
to require that under subpart 4, a state must evaluate all
PM2.5 precursors for regulation unless it provides a
demonstration adequate to rebut the presumption for a particular
precursor in a particular nonattainment area.
---------------------------------------------------------------------------

    \23\ Section 189(e) of the CAA states that ``[t]he control
requirements applicable under plans in effect under this part for
major stationary sources of PM10 shall also apply to
major stationary sources of PM10 precursors, except where
the Administrator determines that such sources do not contribute
significantly to PM10 levels which exceed the standard in
the area.''
---------------------------------------------------------------------------

    The provisions of subpart 4 do not define the term ``precursor''
for purposes of PM2.5, nor do they explicitly require the
control of any specifically identified particulate matter (PM)
precursor. The statutory definition of ``air pollutant,'' however,
provides that the term ``includes any precursors to the formation of
any air pollutant, to the

extent the Administrator has identified such precursor or precursors
for the particular purpose for which the term `air pollutant' is
used.'' CAA section 302(g). The EPA has identified SO2,
NOX, VOC, and ammonia as precursors to the formation of
PM2.5. Accordingly, the attainment plan requirements of
subpart 4 presumptively apply to emissions of all four precursor
pollutants and direct PM2.5 from all types of stationary,
area, and mobile sources, except as otherwise provided in the Act (e.g.
CAA section 189(e)).
    Section 189(e) of the Act requires that the control requirements
for major stationary sources of direct PM10 also apply to
major stationary sources of PM10 precursors, except where
the Administrator determines that such sources do not contribute
significantly to PM10 levels that exceed the standard in the
area. Section 189(e) contains the only express exception to the control
requirements under subpart 4 (e.g., requirements for RACM and RACT,
best available control measures (BACM) and best available control
technology (BACT), most stringent measures, and NSR) for sources of
direct PM2.5 and PM2.5 precursor emissions.
Although section 189(e) explicitly addresses only major stationary
sources, the EPA interprets the Act as authorizing it also to
determine, under appropriate circumstances, that regulation of specific
PM2.5 precursors from other source categories in a given
nonattainment area is not necessary. For example, under the EPA's
longstanding interpretation of the control requirements that apply to
stationary, area, and mobile sources of PM10 precursors
area-wide under CAA section 172(c)(1) and subpart 4 (see General
Preamble, 57 FR 13498 at 13539-42), a state may demonstrate in a SIP
submittal that control of a certain precursor pollutant is not
necessary in light of its insignificant contribution to ambient
PM10 levels in the nonattainment area.\24\
---------------------------------------------------------------------------

    \24\ Courts have upheld this approach to the requirements of
subpart 4 for PM10. See, e.g., Assoc. of Irritated
Residents v. EPA, et al., 423 F.3d 989 (9th Cir. 2005).
---------------------------------------------------------------------------

    We are evaluating the SJV PM2.5 Plan in accordance with
the presumption embodied within subpart 4 that all PM2.5
precursors must be addressed in the state's evaluation of potential
control measures, unless the state adequately demonstrates that
emissions of a particular precursor do not contribute significantly to
ambient PM2.5 levels that exceed the PM2.5 NAAQs
in the nonattainment area. In reviewing any determination by the state
to exclude a PM2.5 precursor from the required evaluation of
potential control measures, we consider both the magnitude of the
precursor's contribution to ambient PM2.5 concentrations in
the nonattainment area and the sensitivity of ambient PM2.5
concentrations in the area to reductions in emissions of that
precursor.
2. Evaluation of Precursors in SJV PM2.5 Plan and Supplement
    In the 2012 PM2.5 Plan, the State and District identify
NOX, and SOX as the precursors that it must
control in order to attain the 2006 PM2.5 standard in the
San Joaquin Valley within 10 years of the area's designation as
nonattainment for the PM2.5 NAAQS (i.e., by 2019).\25\
Although no technical demonstration is necessary to support a
conclusion consistent with the regulatory presumptions under subpart 4,
the Plan nevertheless provides supporting evidence describing the need
for NOX and SOX controls. The Plan states that
further reductions in VOC and ammonia emissions would not contribute to
attainment of the PM2.5 standard in the area and provides
analyses to support this position. In the following, we discuss the
technical basis that the District provided in the Plan to support its
positions with respect to SO2, NOX, VOC, and
ammonia.
---------------------------------------------------------------------------

    \25\ This identification is made in the 2012 PM2.5
Plan, Appendix G, ``PM2.5 Weight of Evidence Analysis''
(``WOEA'') at pp. iv and 66, and in the CARB, ``Staff Report,
Proposed Revision to the PM2.5 State Implementation Plan
(SIP) for the San Joaquin Valley,'' Release Date: January 11, 2013
(``Staff Report'') at p. 9, which can be found in the docket for
this proposed rule. The WOEA is also included as Appendix B to the
Staff Report.
---------------------------------------------------------------------------

a. SO2
    The 2012 PM2.5 Plan recognizes that emissions of
SO2 contribute significantly to ambient PM2.5
levels in the San Joaquin Valley, and that ambient PM2.5
concentrations are sensitive to reductions in SO2.
    The 2012 PM2.5 Plan shows the measured contribution of
SO2 emissions to ambient PM2.5 concentrations in
pie charts portraying the contribution of various pollutant species.
Depending on time period and location, the ammonium sulfate
contribution is 6 to 9 percent,\26\ and the corresponding contribution
of just the sulfate part of the ammonium sulfate molecules is 4 to 7
percent of ambient PM2.5. The Plan's ``Weight of Evidence
Analysis'' (``WOEA'') also gives the ammonium sulfate portion of the
2007 design value concentration, 4.7 [mu]g/m\3\ at Bakersfield.\27\ The
corresponding sulfate-only portion is 3.4 [mu]g/m\3\. These
contribution levels are substantial, although smaller than the
contributions of some other components.
---------------------------------------------------------------------------

    \26\ 2009-2010 peak day average in 2012 PM2.5 Plan
Appendix A, Figures A-29 and A-30, p. A-52; 2009-2011 peak day
average in WOEA Figure 7, p. 10.
    \27\ WOEA at Table 5, p. 63.
---------------------------------------------------------------------------

    Ambient PM2.5 sensitivity to reductions of
SO2 emissions is also presented in the Plan in the form of
modeling results. The results from the sensitivity modeling is cited
and discussed below in the NOX subsection. The
SO2-specific results are that a 25% reduction in Valley-wide
SO2 emissions would result in a 0.18 [mu]g/m\3\ decrease in
ambient PM2.5 concentrations at the design value monitoring
site, Bakersfield-California. It can also be inferred from the modeling
that there is an ambient PM2.5 decrease of 0.08 [mu]g/m\3\
per ton of SO2 reduction (WOEA, Tables 6 and 7, p. 65). The
0.18 [mu]g/m\3\ PM2.5 decrease for a 25% SO2
reduction is considerably lower than the 3.75 [mu]g/m\3\ decrease that
would result from a 25% NOX reduction, but the 0.08 [mu]g/
m\3\ PM2.5 decrease per ton of emissions reduction is the
same for SO2 as it is for NOX. The reason the 25%
NOX reduction provides a larger reduction in ambient
PM2.5 levels than a 25% SO2 reduction is simply
that the NOX emission inventory for the area is much larger
than the SO2 inventory. The 2007 winter planning inventory
for SO2 is just 12.8 tpd, whereas for NOX it is
465.1 tpd, more than 35 times larger (see 2012 PM2.5 Plan at
Appendix B, Emission Inventory, grand totals in tables B-3 for
SO2 and B-2 for NOX.) Even though the relatively
small SO2 contribution to ambient PM2.5
concentrations leaves little scope for reductions, the sensitivity of
ambient PM2.5 to SO2 emission reductions
indicates that SO2 emissions contribute significantly to
PM2.5 levels above the standards.
    Based on the technical analyses provided in the Plan, the EPA
agrees with the State's and District's conclusion that SO2
controls must be included in the evaluation of potential control
measures for the 2006 PM2.5 standard in the SJV, consistent
with the requirements of subpart 4.
b. NOX
    The 2012 PM2.5 Plan recognizes that emissions of
NOX contribute significantly to ambient PM2.5
levels in the San Joaquin Valley, and that ambient PM2.5
concentrations are sensitive to reductions in NOX. The Plan
discusses NOX in conjunction with ammonia, because these
precursors react together to create ammonium

nitrate, the largest component of ambient PM2.5 particles by
species in the SJV.\28\ The chemical products of ammonia and
NOX (ammonium and nitrate) combine in a 1:1 molecular ratio,
but as discussed below, this ratio does not mean that emissions
controls for the two precursor pollutants would be equally effective at
reducing ambient PM2.5. The Plan provides several lines of
evidence to indicate that reductions in NOX emissions are
effective in reducing PM2.5 concentrations exceeding the
standard, and also that they are more effective than reductions in
ammonia emissions. The evidence includes ambient contributions, model
simulations of NOX emission reductions, historical trends,
and the relative amounts of NOX and ammonia.
---------------------------------------------------------------------------

    \28\ 2012 PM2.5 Plan Appendix A, Figures A-30 and A-
29, p. A-52.
---------------------------------------------------------------------------

    The Plan indicates that the ambient contribution of NOX
to PM2.5 levels in the SJV is substantial. Ammonium nitrate
is the largest chemical component of ambient PM2.5 in the
SJV, comprising 65 percent of the 2009-2011 average peak 24-hour
PM2.5 concentration at Bakersfield (WOEA, p. 10). Using the
2009-2011 24-hour PM2.5 design value of 61.8 [mu]g/m\3\,\29\
the ammonium nitrate concentration on peak PM2.5 days is
approximately 40.2 [mu]g/m\3\. If only nitrate itself is considered
(i.e., the nitrate part of the ammonium nitrate molecules), the
contribution of NOX represents approximately 50.3 percent of
the 2009-2011 average peak 24-hour PM2.5 concentration at
Bakersfield, which is an ambient contribution of 31.1 [mu]g/m\3\.\30\
Whether considered as ammonium nitrate or simply as nitrate,
NOX is clearly a significant contributor to ambient
PM2.5 levels above the standard in the SJV.
---------------------------------------------------------------------------

    \29\ See 2012 PM2.5 Plan, p. A-10. The design value
for Bakersfield-California for 2009-2011 is given as a rounded value
of 62 [mu]g/m\3\ in Table A-5 in Appendix A of the Plan. For greater
precision in estimating species contributions, we have used the
unrounded value of 61.8 [mu]g/m\3\ calculated as the average of the
98th percentiles values for each year (66.7, 53.3, and 65.5) as
listed in Table A-4.
    \30\ The nitrate fraction of ammonia nitrate is calculated as
molecular weight of nitrate (62) divided by the molecular weight of
ammonium nitrate (80) and equals 77.5 percent.
---------------------------------------------------------------------------

    In addition to this evidence on the contribution of NOX
to PM2.5 concentrations, the Plan provides evidence that
ambient PM2.5 concentrations are sensitive to NOX
reductions (i.e., nitrate PM2.5 concentrations go down when
NOX emissions are reduced). The evidence is from modeling,
historical trends, and relative proportions of NOX and
ammonia. The 2012 PM2.5 Plan provides evidence from past and
current photochemical modeling simulations that ambient ammonium
nitrate is sensitive to NOX reductions. The Plan describes
past modeling studies that were documented in academic journals.\31\ In
the various studies, when NOX emissions were reduced by 50
percent, ambient ammonium nitrate decreased by 25 to 50 percent,
depending on the episode modeled and the geographic location.\32\
Modeling for the 2012 PM2.5 Plan also shows substantial
sensitivity of ambient PM2.5 concentrations to reductions in
NOX emissions. In the Plan, the State modeled a 25 percent
reduction in NOX emissions and showed a decrease in
Bakersfield PM2.5 concentrations of 3.75 [mu]g/m\3\, a 6
percent decrease in the 2009-2011 design value of 61.8 [mu]g/m\3\ and
similar levels of ambient decreases at other monitors (WOEA, Table 6,
p. 65).
---------------------------------------------------------------------------

    \31\ The academic journal papers and are described in Appendix
F, section 2.7 (p. 28), and in WOEA, section 5.c (p. 64).
    \32\ Kleeman, M.J., Ying, Q., and Kaduwela, A., Control
strategies for the reduction of airborne particulate nitrate in
California's San Joaquin Valley, Atmospheric Environment, 2005, 39,
5325-5341. Liang, J., G[uuml]rer, K., Allen, P.D., Zhang, K.M.,
Ying, Q., Kleeman, M., Wexler, A., and Kaduwela, A., 2006, A
photochemical model investigation of an extended winter PM episode
observed in Central California: Model Performance Evaluation,
Proceedings of the 5th Annual CMAQ Models-3 User's Conference,
Chapel Hill, NC. Pun, B.K., Balmori R.T.F, and Seigneur, C., 2009,
Modeling wintertime particulate matter formation in Central
California, Atmospheric Environment, 43, 402-409. Different models
and emission inventories in these studies conducted over the years
also contribute to the variation in results.
---------------------------------------------------------------------------

    The 2012 PM2.5 Plan provides additional (non-modeling)
evidence on the effectiveness of NOX reductions. The
historical downward trends of NOX emissions and of ambient
nitrate concentrations are discussed in Chapter 4 and the WOEA of the
Plan.\33\ Daily NOX emissions levels and winter nitrate
concentrations appear correlated over time on an annual basis. Both
have decreased by about a third during the period 2004 to 2011. This is
evidence that existing NOX controls are effective at
reducing ammonium nitrate. The evidence is strengthened by the fact
that this reduction in ambient nitrate occurred despite an increase in
emissions of ammonia, the other precursor to ammonium nitrate, during
the same period (Plan p. 4-8).
---------------------------------------------------------------------------

    \33\ 2012 PM2.5 Plan, Chapter 4, p. 4-8 and Figure 4-
7, p. 4-10; more detail in WOEA section 9, p. 58, Figures 49-52.
---------------------------------------------------------------------------

    The Plan further describes the effectiveness of NOX
controls by characterizing it as the ``limiting precursor'' in ammonium
nitrate formation, based on the relative amounts of NOX and
ammonia. Based on monitored concentrations and the emissions inventory,
the Plan concludes that NOX is the limiting precursor. The
limiting precursor concept is illustrated briefly in Chapter 4 and
described more fully in the WOEA.\34\ One molecule of each of
NOX and ammonia is required to form each molecule of
ammonium nitrate. If NOX is in short supply relative to
ammonia, then NOX is the limiting factor in ammonium nitrate
formation.\35\
---------------------------------------------------------------------------

    \34\ Chapter 4, Figures 4-4 and 4-5 (Plan, p. 4-9); WOEA,
section 5b, p. 16. See also CARB Staff Report, p. E-3.
    \35\ As noted below in the ammonia subsection, the ``limiting
precursor'' concept is not absolute, and must be used with caution.
However, for NOX it does support evidence from the
modeling results that NOX significantly contributes to
PM2.5 exceedances.
---------------------------------------------------------------------------

    The WOEA includes plots (Figures 16 and 17, p. 19) of ammonia and
nitric acid (which contains nitrate) concentrations at two monitoring
sites in the SJV (Angiola and Fresno) that were measured during the
winter 2000-2001 CRPAQS \36\ study and reported in Lurmann et al.
(2006).\37\ The Plan notes that ammonia concentrations are at least an
order of magnitude larger than those of nitrate and notes Lurmann et
al.'s conclusion that NOX is the limiting precursor.
---------------------------------------------------------------------------

    \36\ CRPAQS is the California Regional Particulate Air Quality
Study. More information is available about CRPAQS at http://www.arb.ca.gov/airways/ccaqs.htm.
    \37\ Lurmann, F.W., Brown, S.G., McCarthy, M.C., and Roberts,
P.T., December 2006, Processes Influencing Secondary Aerosol
Formation in the San Joaquin Valley during Winter, Journal of Air
and Waste Management Association, 56, 1679-1693.
---------------------------------------------------------------------------

    The WOEA also considers emissions inventories to support the
argument that NOX is the limiting precursor. The WOEA
normalized NOX emissions using the relative molecular
weights of NOX and ammonia, in order to reflect the number
of molecules of each available to react with each other (p. 18, Table
1). In 2000, the amount of NOX available was only about two-
thirds the amount of ammonia; in 2011 NOX was only one-third
of ammonia. This shows the scarcity of NOX relative to
ammonia and implies that NOX is the limiting precursor in
the formation of ammonium nitrate.
    Based on the range of technical analyses provided in the Plan and
other information available to EPA, the EPA agrees with the State's and
District's conclusion that NOX controls must be included in
the evaluation of potential control measures for the 2006
PM2.5 standard in the SJV, consistent with the requirements
of subpart 4.
c. Ammonia
    The 2012 PM2.5 Plan and Supplement state that
``[b]ecause of the regional

surplus in ammonia, even substantial ammonia emissions reductions yield
a relatively small reduction in nitrate'' (Plan p. 4-8) and that
``ammonia reductions would not significantly contribute to the Valley's
attainment of the 2006 PM2.5 standard'' (Plan p. 4-11). To
support this finding, the Plan and Supplement discuss the ambient
contribution of ammonia to measured PM2.5 levels in the SJV,
and the sensitivity of ambient PM2.5 to ammonia reductions.
The latter includes discussion of the relative abundance of
NOX and ammonia, and of modeled simulations of further
reductions in ammonia emissions.
    The Plan indicates that ammonia contributes to ambient
concentrations of PM2.5, in the form of ammonium nitrate and
ammonium sulfate. As noted above in the NOX discussion,
ammonium nitrate contributes 65 percent of the 2009-2011 average peak
PM2.5 ambient levels at Bakersfield. Ammonium sulfate
contributes an additional 7 percent (p. G-10; WOEA, p. 10). Thus,
ammonium nitrate and ammonium sulfate together account for a total of
72 percent of the peak 24-hour PM2.5 concentrations, or 44.5
[mu]g/m\3\, and ammonia emissions are essential to the formation of
both of these components of the ambient particulate matter. If only the
ammonium portion of these molecules is considered, the corresponding
figures are 16.6 percent of peak PM2.5 ambient levels, or
10.3 [mu]g/m\3\.\38\ This level of contribution is a substantial
fraction of the SJV's 2009-2011 design value of 61.8 [mu]g/m\3\, and
indicates that emissions of ammonia contribute significantly to ambient
PM2.5 concentrations that exceed the 24-hour
PM2.5 standard in the SJV.
---------------------------------------------------------------------------

    \38\ The ammonium fraction of ammonia nitrate is calculated as
molecular weight of ammonium (18) divided by the molecular weight of
ammonium nitrate (80) and equals 23.5 percent. The ammonium fraction
of ammonia sulfate is calculated as molecular weight of ammonium
portion (36) divided by the molecular weight of ammonium sulfate
(132) and equals 27.3 percent.
---------------------------------------------------------------------------

    Next we examine information in the Plan regarding the sensitivity
of ambient PM2.5 levels in the SJV to ammonia emission
control. On this issue there is conflicting evidence. Based on evidence
that ammonia is not the limiting precursor and that modeled ammonia
reductions are relatively ineffective, the Plan concludes that controls
for ammonia are not warranted. However, a detailed evaluation of the
modeling shows that ammonia controls can be effective at reducing
ambient PM2.5 in some locations.
    The Plan's evidence discussed above to support the argument that
NOX is the limiting precursor for ammonia nitrate formation
is also presented as evidence that ammonia is not the limiting
precursor, and so ambient PM2.5 would not be sensitive to
ammonia reductions (WOEA, p. 16-20). The Plan notes that there is both
an abundance of ambient ammonia relative to ambient nitrate, and an
abundance of ammonia emissions relative to NOX emissions.
The Plan also indicates that there is an abundance of gaseous ammonia
relative to particulate ammonium at multiple locations during the 2000-
2001 winter episode in the CRPAQS study (WOEA, p. 20 and Figure 18).
This abundance suggests that even under conditions favorable to
ammonium nitrate formation, a substantial amount of unreacted ammonia
remains. Based on these multiple pieces of evidence on the abundance of
ammonia, the Plan concludes that ammonia is not the limiting factor for
ammonium nitrate formation and, thus, that reducing ammonia emissions
would not reduce ambient PM2.5 in the SJV.
    The 2012 PM2.5 Plan also considered air quality modeling
analyses to evaluate the effectiveness of reducing ammonia as compared
to other precursors, and to PM2.5 decreases needed for
attainment. Modeling for the 2012 PM2.5 Plan indicated that
a 25 percent reduction in ammonia emissions resulted in a 0.55 [mu]g/
m\3\ decrease in ambient PM2.5 (WOEA, p. 65, Table 6). This
benefit is roughly one-seventh the corresponding benefit for a 25
percent reduction in NOX. Id. Restating the inventory
reduction percentages in terms of tons per day reductions, the Plan
notes that reducing ammonia emissions by one ton per day is only about
10 percent as effective as reducing one ton per day of NOX
(Plan p. 4-11). Thus, based on this air quality modeling, the Plan
concludes that additional ammonia control is considerably less
effective than NOX control.
    The Plan also notes that, assuming the same rate of improvement in
ambient PM2.5 concentration per ton of ammonia reduced, it
would take a 34 percent reduction in ammonia emissions to decrease
ambient PM2.5 by 1 [mu]g/m\3\, the amount that would have
been needed to advance projected attainment by one year from 2019 to
2018. The Plan considers this to be ``an infeasible amount, since there
are no control strategies that exist or have been identified which
could achieve such large reductions'' (Plan, p. 4-11).
    The Plan assumes that additional ammonia control, as modeled, would
provide limited benefit for attainment planning purposes. The Plan
concludes, based upon the various information and analyses described
above, that ``ammonia reductions would not significantly contribute to
the Valley's attainment of the 2006 PM2.5 standard'' (Plan
p. 4-11), and therefore additional control measures should not be
evaluated.
    After reviewing the information discussed above, EPA believes that
the information provided by the State and District in the Plan and
Supplement shows that ammonia contributes to a large fraction of
measured PM2.5 concentrations in the SJV area, in the form
of ammonium nitrate and ammonium sulfate. Additionally, modeling
analyses submitted by the State and studies available to EPA indicate
that although ammonia control is generally less effective at reducing
PM2.5 concentrations when compared to NOX
control, it remains true that reducing ammonia emissions in the SJV
would reduce PM2.5 by varying amounts throughout the
nonattainment area. Moreover, reductions in ammonia in conjunction with
reductions of SO2 and NOX would help to provide
for attainment of the NAAQS in the SJV.
    While EPA finds the modeling and other analyses presented in the
2012 PM2.5 plan to be credible, the fact remains that the
modeling analyses show that additional reductions in ammonia may reduce
ambient PM2.5 levels to varying degrees. In the various
studies, when ammonia emissions were reduced by up to 50 percent,
ambient ammonium nitrate decreased by 5 to 25 percent, depending on the
episode modeled and the geographic location evaluated. (WOEA, p. 64)
These percentages for ammonia benefits are generally smaller than those
for NOX reductions, but these modeling results show that
reductions in ammonia emissions under certain circumstances can
effectively reduce ambient PM2.5. The fact that all the
modeling studies, including the modeling done for the current Plan,
find at least some benefit from ammonia control shows that the concept
of a ``limiting precursor'' discussed above is not absolute. In
addition, the test for determining whether emission reduction measures
for a particular precursor must be evaluated for purposes of timely
attainment should not be exclusively based on the control effectiveness
of the precursor relative to other precursors, but should also consider
whether emissions of the precursor ``contribute significantly'' to
ambient PM2.5 levels which exceed the PM2.5
standard in the nonattainment area.
    Regarding the Plan's statement that it would take a 34 percent
reduction in

ammonia emissions to decrease ambient PM2.5 by 1 [mu]g/m\3\,
the amount needed to advance attainment by one year from 2019 to 2018,
EPA notes that the test for advancing the attainment date is based not
on an evaluation of control measures for a single pollutant but rather
on an evaluation of potential control measures for direct
PM2.5 and all PM2.5 precursors from all types of
sources in the nonattainment area. We also note that the appropriate
inquiry in this context is whether reasonably available control
measures would advance attainment by one year from 2015 to 2014 (not
from 2019 to 2018), given under subpart 4 the applicable attainment
date for the SJV area for the 2006 PM2.5 NAAQS is December
31, 2015.
    In summary, the information provided by the State and District in
the Plan and Supplement shows that ammonia contributes to a large
fraction of measured PM2.5 concentrations in the SJV area,
in the form of ammonium nitrate and, to a lesser extent, ammonium
sulfate. Additionally, modeled evidence submitted by the State and
studies available to EPA indicate that although ammonia control is less
effective at reducing PM2.5 concentrations compared to
NOX control, reducing ammonia emissions in the SJV would
reduce PM2.5 by some amount in parts of the Valley. Given
the severity of the PM2.5 nonattainment problem in the SJV,
the demonstration that attainment in SJV by 2015 is impracticable, and
the documentation in the 2012 PM2.5 Plan showing that
ammonia emissions are responsible for more than 10 [mu]g/m\3\ of
ambient PM2.5 concentrations in the SJV area, EPA does not
agree with the statement in the Plan that additional ammonia controls
need not be evaluated to satisfy CAA requirements for the 2006
PM2.5 standard in the SJV.
    While stating that additional ammonia reductions are not necessary,
the State nevertheless provided in the Supplement an evaluation of
ammonia control measures currently implemented in the SJV and other
potential ammonia control measures. We discuss the State's ammonia
control evaluation in section D, below (``Reasonably Available Control
Measures/Reasonably Available Control Technology'').
d. VOC
    The 2012 PM2.5 Plan states that further reductions in
VOC emissions would not contribute to PM2.5 attainment in
the San Joaquin Valley. To support this finding, the Plan discusses the
ambient contribution of VOC to measured PM2.5 levels in the
Valley, the indirect role of VOC in ammonium nitrate formation, and
modeled simulations of further reductions in VOC emissions.
    There are two routes by which VOC can contribute to ambient
PM2.5. The first is through various chemical reactions
leading to the formation of Secondary Organic Aerosols (SOA). The
second is through photochemical reactions that create oxidants such as
ozone and the hydroxyl radical (OH), which in turn oxidize
NOX emissions to nitrate, leading to the formation of
particulate ammonium nitrate. The Plan's Chapter 4 (p. 4-12) discussed
both routes in section 4.4.2. The WOEA discusses SOA in section 6
(WOEA, p. 32) and the oxidant route in section 5d (WOEA, p. 24).
    For the direct contribution of VOC to PM2.5, SOA, the
2012 PM2.5 Plan states that modeling for annual average
PM2.5 for the 2008 PM2.5 Plan found that
anthropogenic SOA were about 3 to 5 percent of total organic aerosol,
and that SOA were mainly formed during the summer from nonanthropogenic
sources. The winter anthropogenic contribution that is of interest for
the 24-hour PM2.5 standard would necessarily be lower, since
SOA formation is less at winter temperatures, which are lower than the
annual average. The Plan also cites a study by Chen et al. \39\ for the
winter 2000-2001 CRPAQS episode. This study found that the SOA portion
of total organic aerosol had a maximum value of 4.26 [mu]g/m\3\ with
concentrations at Fresno and Bakersfield of 2.46 and 2.28 [mu]g/m\3\,
respectively, which represent 6 percent and 4 percent of the total
organic aerosol at those locations. Applying this roughly 5 percent SOA
proportion to the organic carbon portion of the measured 2009-2011
winter PM2.5 composition shows that SOA is around 0.9
percent of total ambient PM2.5 at Bakersfield, and 1.5
percent of ambient PM2.5 at Fresno.\40\ Because
anthropogenic SOA is only a portion of the total, the portion due to
controllable anthropogenic sources would be even less. These modeling
studies show that SOA is not a substantial component of ambient
PM2.5 in the SJV and that the potential for reducing ambient
PM2.5 through VOC emission reductions is very limited.
---------------------------------------------------------------------------

    \39\ Chen, J., Ying, Q., and Kleeman, M.J., 2010, Source
apportionment of wintertime secondary organic aerosol during the
California regional PM10/PM2.5 air quality
study, Atmospheric Environment, 44(10), 1331-1340.
    \40\ The contribution of Organic Matter to 2009-2011 peak day
PM2.5 levels was 17 percent at Bakersfield and 29 percent
at Fresno (see Staff Report, Appendix B, p. 10 [pdf.52], Figure 6.
Five percent of these gives 0.85 percent SOA at Bakersfield and 1.45
percent at Fresno. As a fraction of the 2007 design values of 66
[mu]g/m\3\ at Bakersfield and 63 [mu]g/m\3\ at Fresno, these give
SOA contributions of 0.56 and 0.91 [mu]g/m\3\ at Bakersfield and
Fresno, respectively.
---------------------------------------------------------------------------

    For the indirect contribution of VOC to PM2.5, nitrate
formation via daytime photochemistry, it appears that this route is
also not a substantial contributor, based on modeled sensitivity to VOC
reductions. For one such study there were relatively low modeled
concentrations of ozone, which did not appear consistent with nitrate
formation via daytime oxidant (ozone) photochemistry, which would be
expected to have elevated ozone levels.\41\ The Plan reviews the same
studies that the State relied on in the 2008 PM2.5 Plan for
attainment of the 1997 PM2.5 standards (Plan Modeling
Protocol, p. F-31). The EPA's review of these studies and of the 2008
PM2.5 Plan's examination of them is covered in the TSD for
the EPA's final action on the 2008 PM2.5 Plan.\42\ The
findings from those reviews remain the same for the current Plan: past
modeling studies vary on whether controlling VOC reduces
PM2.5, but the most reliable ones show VOC control has
little benefit, or even a disbenefit. As detailed in that previous TSD
and in the Plan's Modeling Protocol, the studies for which VOC control
showed a benefit at some times and places are less reliable because
they used unrealistic emissions levels, unrealistic control scenarios,
or the effect occurred at PM2.5 concentrations no longer
reached in the SJV. The Protocol also suggested that there is
sufficient background ozone flowing in from outside the SJV area to
perform the oxidizing role, even in the absence of oxidants generated
from VOC emissions within the SJV,\43\ implying that VOC reductions
would have little effect on ambient PM2.5 levels exceeding
the standard in the SJV. The overall conclusion is that the effect of
reducing VOC emissions is somewhat uncertain, but in general produces
little benefit or

even a disbenefit in PM2.5 concentrations.
---------------------------------------------------------------------------

    \41\ Pun, B.K., Balmori R.T.F, and Seigneur, C., 2009, Modeling
Wintertime Particulate Matter Formation in Central California,
Atmospheric Environment, 43: 402-409. doi: 10.1016/
j.atmosenv.2008.08.040.
    \42\ EPA-Region 9, Technical Support Document and Responses to
Comments Final Rule on the San Joaquin Valley 2008 PM2.5
State Implementation Plan,'' September 30, 2011, section II.C.
    \43\ Kleeman, M.K., Ying, Q., and Kaduwela, A., 2005, Control
strategies for the reduction of airborne particulate nitrate in
California's San Joaquin Valley, Atmospheric Environment, 39: 5325-
5341 September 2005. doi:10.1016/j.atmosenv.2005.05.044; cited in
Plan Modeling Protocol. p. F-36).
---------------------------------------------------------------------------

    Added to this evidence from past studies is the 2012 Plan's current
modeling, which indicates a disbenefit from controlling VOC at
important geographic locations. This is shown by negative
PM2.5 sensitivities (that is, decreased VOC emissions result
in increased PM2.5 levels) for multiple locations.\44\ In
addition, diagrams of model PM2.5 response at Bakersfield to
various combinations of NOX and VOC reductions show
graphically that VOC reductions increase PM2.5, for any
given level of NOX.\45\ For all the monitoring sites, these
NOX vs. VOC diagrams show either no decrease or an actual
increase in PM2.5 as VOC emissions are reduced. The current
modeling provides strong evidence that additional VOC reductions would
not decrease ambient PM2.5 concentrations in the SJV.
---------------------------------------------------------------------------

    \44\ See VOC columns of WOEA Tables 6 and 7 (p. 65) for
Bakersfield, Visalia, Corcoran, and Merced.
    \45\ WOEA Figure 54 (p. 67) shows the model PM2.5
response at Bakersfield to reductions in various combinations of
precursors. Subfigure ``b)'' shows NOX reductions plotted
against VOC reductions. For a given level of NOX, in
decreasing VOC by moving leftward along a horizontal line
(representing constant NOX), one crosses the lines of
constant PM2.5 (isopleths) into regions of increased
PM2.5. The Plan presents similar diagrams in Chapter 4,
Figures 4-15 through 4-23 (pp. 4-31ff) for the various monitoring
sites.
---------------------------------------------------------------------------

    In sum, the information provided by the State and District in the
Plan and Supplement shows that: (a) wintertime levels of secondary
organic aerosol measured in the SJV are low and therefore the direct
products of VOC emissions do not directly contribute significantly to
PM2.5 levels above the standard in the SJV; and (b)
wintertime reductions in VOC emissions in the SJV, when
PM2.5 concentrations are high, would not reduce ambient
PM2.5 levels, and therefore the indirect products of VOC
emissions also do not directly contribute significantly to
PM2.5 levels above the standard in the SJV. Based on this
information, we propose to determine that at this time VOC emissions do
not contribute significantly to ambient PM2.5 levels that
exceed the 2006 PM2.5 standard in the SJV nonattainment
area.
3. Proposed Action
    Based on a review of the information provided by the District and
other information available to EPA, we propose to determine that at
this time VOC emissions do not contribute significantly to ambient
PM2.5 levels which exceed the 2006 PM2.5 standard
in the SJV and, therefore, that VOCs may be excluded from the State's
evaluation of potential control measures for purposes of this standard
in this area. Consistent with the regulatory presumptions under subpart
4, all other PM2.5 precursors (NOX,
SO2, and ammonia) must be included in the State's evaluation
of potential control measures for the 2006 PM2.5 standard in
the SJV area, including NNSR provisions to implement the requirements
of subpart 4.\46\ We discuss the State's evaluation of potential
control measures for NOX, SO2, and ammonia, as
well as direct PM2.5, in section D (``Reasonably Available
Control Measures/Reasonably Available Control Technology'').
---------------------------------------------------------------------------

    \46\ Absent a demonstration to EPA's satisfaction that major
stationary sources of ammonia emissions do not contribute
significantly to ambient PM2.5 levels that exceed the
NAAQS in the SJV area, under CAA section 189(e) major stationary
sources of ammonia are subject to the control requirements that
apply to major stationary sources of direct PM2.5,
including NNSR requirements. We intend to evaluate the adequacy of
SJV's NNSR program for PM2.5 purposes in a separate
rulemaking.
---------------------------------------------------------------------------

D. Reasonably Available Control Measures/Reasonably Available Control
Technology

1. Requirements for RACM/RACT
    CAA section 172(c) under subpart 1 describes the general attainment
plan requirement for RACM and RACT, requiring that attainment plan
submissions ``provide for the implementation of all reasonably
available control measures as expeditiously as practicable (including
such reductions in emissions from existing sources in the area as may
be obtained through the adoption, at a minimum, of reasonably available
control technology) and shall provide for attainment'' of the NAAQS.
The attainment planning requirements specific to PM2.5 under
subpart 4 likewise impose upon states an obligation to develop
attainment plans that require RACM on sources of direct
PM2.5 and those PM2.5 precursors determined to be
subject to the RACM/RACT requirement. CAA section 189(a)(1)(C) requires
that Moderate area PM2.5 SIPs contain provisions to assure
that RACM are implemented by no later than 4 years after designation of
the area. The EPA reads CAA sections 172(c)(1) and 189(a)(1)(C)
together to require that attainment plans for Moderate nonattainment
areas must provide for the implementation of RACM and RACT for existing
sources of PM2.5 and PM2.5 precursors in the
nonattainment area as expeditiously as practicable but no later than 4
years after designation.\47\ As part of the RACM/RACT analysis, all
available controls should be evaluated, and reasonable controls should
be adopted.
---------------------------------------------------------------------------

    \47\ This interpretation is consistent with guidance provided in
the General Preamble at 13540.
---------------------------------------------------------------------------

    The terms RACM and RACT are not specifically defined in the Act,
nor do the provisions of subpart 4 specify how states are to meet the
RACM and RACT requirements. In longstanding guidance, however, the EPA
has interpreted the RACM requirement to include any potential control
measure for a point, area, on-road and non-road emission source that is
technologically and economically feasible (General Preamble at 13540)
and is not ``absurd, unenforceable, or impracticable'' (General
Preamble at 13560). The EPA has historically defined RACT as the lowest
emission limitation that a particular stationary source is capable of
meeting by the application of control technology (e.g., devices,
systems, process modifications, or other apparatus or techniques that
reduce air pollution) that is reasonably available considering
technological and economic feasibility. See General Preamble at 13541
and 57 FR 18070, 18073-74 (April 28, 1992).
    The EPA recommends that states use the following process to
identify RACM/RACT:

    1. Develop a comprehensive list of available control measures
for all source categories in the nonattainment area. In developing
this list, the state should identify existing control measures
currently being implemented in the area and also include any control
measures suggested in public comments.
    2. Remove from the list any measure that is unreasonable because
emissions from the affected source or source category are
insignificant (i.e., de minimis). The state should appropriately
document any determination that a source or source category is
insignificant.
    3. Evaluate each remaining available control measure for its
``reasonableness,'' considering technological and economic
feasibility and any potentially adverse impacts. The state should
provide a reasoned justification if it rejects a listed control
measure as unreasonable.
    4. Include in its submitted Moderate area attainment plan, in
enforceable form, each control measure found to be reasonable unless
the measure is already either federally promulgated, part of the
state's SIP, or otherwise creditable in SIPs. In areas that
demonstrate attainment by the Moderate area attainment date, the
state may justify rejection of an otherwise reasonable measure by
demonstrating that the measure would not, individually or
collectively with other reasonable measures being rejected, advance
attainment by one year or more. For areas that demonstrate that
attainment by the Moderate area attainment date is impracticable,
the state must provide for the implementation of all available
control measures that are technologically and economically feasible.

See General Preamble at 13540-13544.
    An evaluation of technological feasibility should include
consideration of factors such as a source's process and operating
conditions, raw materials, physical plant layout, and non-air quality
and energy impacts (e.g., increased water pollution, waste disposal,
and energy requirements) (57 FR 18070, 18073).
    An evaluation of economic feasibility should include consideration
of factors such as cost per ton of pollution reduced (cost-
effectiveness), capital costs, and annualized cost (57 FR 18070,
18074). Absent other indications, the EPA presumes that it is
reasonable for similar sources to bear similar costs of emissions
reductions. Economic feasibility of RACM and RACT is thus largely
informed by evidence that other sources in a source category have in
fact applied the control technology, process change, or measure in
question in similar circumstances. Id.
2. RACM/RACT Analysis in the 2012 PM2.5 Plan
    The 2012 PM2.5 Plan's RACM/RACT evaluation for direct
PM2.5, NOX and SO2 sources is
summarized in section 9.2 (p. 9-3) and detailed in Appendices C
(``Mobile Source Control Strategies'') and D (``Stationary and Area
Source Control Strategy Evaluation''). RACM for ammonia sources is
discussed in Attachment A of the Supplement. The Plan includes a short
discussion of the District's current VOC control measures (p. 5-17 and
Supplement, p. 13) but includes no detailed evaluation of them. The
treatment of VOCs is thus consistent with the District's determination
that additional VOC controls are not necessary in the SJV area for
purposes of attaining the PM2.5 NAAQS.
    The evaluation of potential controls in the 2012 PM2.5
Plan is presented by source category. For stationary and area source
categories, the evaluation is broken down by the current District rule
or rules that apply to that source category. The evaluation also
addresses a number of source categories that are not currently subject
to emission controls (e.g., fireworks). See 2012 Plan, Appendix D, p.
D-163.
    The following information is provided in Appendix D for each
stationary or area source category or District rule or, for ammonia
sources, in Attachment A to the Supplement:

     A description of the sources within the category or
sources subject to the rule;
     base year (2007), current year (2012), and projected
baseline year emissions (for every year from 2014 to 2019) in the
source category or affected by the rule;
     a discussion of the current rule requirements and/or
listing and discussion of existing rules, regulations, or other
control efforts that address the source category; and
     identification and discussion of potential new
controls, including in many cases, a discussion of the technological
and economic feasibility of the new controls. Rules adopted by other
agencies (including the EPA, South Coast AQMD, and Bay Area AQMD)
are discussed and compared to existing SJV rules. Measures proposed
by the public for the source category/rule are also identified and
discussed. In addition, non-regulatory approaches to reducing
emissions in each stationary and area source category are discussed,
including the use of incentives, opportunities for technology
advancement programs, policy initiatives, and education/outreach
programs.

    The following information is provided in Appendix C for each major
on- and off-road mobile source category:

     A description of the type of sources in the category;
     base year (2007), current year (2012), and projected
baseline year emissions (for every year from 2014 to 2019) in the
source category;
     a discussion of the current rule requirements and/or
listing and discussion of existing rules, regulations, or other
control efforts that address the source category; and
     identification and discussion of potential new
controls. Measures proposed by the public for the source category/
rule are also identified and discussed with the majority of this
discussion presented in the responses to comments in Appendix I, pp.
I-10 to I-13.

    Through this evaluation process, the District identified 5 new
control measures for adoption. The 2012 PM2.5 plan includes
enforceable commitments to adopt these measures. See 2012
PM2.5 Plan, section 5.3.1 (p. 5-21) and Table 2 below.

                      Table 2--SJVAPCD 2012 PM2.5 Plan Specific Rule Amendment Commitments
----------------------------------------------------------------------------------------------------------------
                            Measure number and
   District rule No.           description          Amend date  Comply date       Rule amendment commitment
----------------------------------------------------------------------------------------------------------------
4308..................  Boilers, Steam                    2013         2015  Lower the NOX emission limit for
                         Generators, and Process                              instantaneous water heaters in the
                         Heaters 0.075 to <2                                  size range of 0.075-0.4 MMBtu/hr
                         MMBtu/hr.                                            from the current level of 55 ppmv
                                                                              to 20 ppmv.
4692..................  Commercial Charbroiling..         2016         2017  Add requirements for under-fired
                                                                              charbroilers.
                                                                             1. Lower the threshold level for
                                                                              calling wood-burning curtailments
                                                                              from 30 [mu]g/m3 to >=20 [mu]g/m3.
                                                                             2. Review the meteorological
                                                                              conditions that lead to elevated
                                                                              PM2.5, to prevent the buildup of
                                                                              PM2.5 that may lead to a potential
                                                                              exceedance day.
4901..................  Wood Burning Fireplaces           2016    2016/2017  3. Consider expanding the wood
                         and Wood Burning Heaters.                            burning season to include October
                                                                              and/or March.
                                                                             4. Analyze the feasibility of
                                                                              allowing the use of the cleanest
                                                                              certified wood burning devices at
                                                                              specified curtailment levels.
4905..................  Natural Gas-Fired, Fan            2014         2015  Lower the NOX emission limits for
                         Type Residential Central                             residential furnaces and examine
                         Furnaces.                                            the possibility of incorporating
                                                                              NOX limits for natural gas-fired,
                                                                              fan-type, commercial central
                                                                              furnaces into the rule.
9610..................  SIP Creditability of              2013         2013  Establish appropriate mechanisms
                         Incentives.                                          for the District to take SIP
                                                                              credit for eligible incentive
                                                                              programs.
----------------------------------------------------------------------------------------------------------------
Source: 2012 PM2.5 Plan, p. 5-21, Table 5-3, and section 5.3.1.

    The District also identified a number of source categories for
which existing information is inadequate to determine the feasibility
of additional controls. These categories and the additional controls to
be studied are discussed in section 5.3.3. (p. 5-24). The schedule for
these studies is given in Table 5-4 (p. 5-24).
    The Plan also includes descriptions of the District's incentive
programs

(Chapter 6); its technology advancement program (Chapter 7), and its
public outreach program (Chapter 8).
    The efforts by the SJV's eight metropolitan planning organizations
(MPO) \48\ to implement cost-effect transportation control measures
(TCM) are described in Appendix C, section C-11-4 (p. C-33). While no
additional TCMs were identified by the MPOs, the Plan includes a
discussion of the on-going implementation of a broad range of TCMs in
the Valley. There is also a discussion of the MPOs' Congestion
Management and Air Quality (CMAQ) funding policy which is a
standardized process across the Valley for distributing 20 percent of
the CMAQ funds to projects that meet a minimum cost-effectiveness.
During the comment period for the 2012 PM2.5 Plan, a number
of TCMs were suggested by the public for consideration. See Appendix I,
pp. I-10 to I-13. The feasibility of these measures is discussed in the
District's responses to comments. Id.
---------------------------------------------------------------------------

    \48\ These eight MPOs represent the eight counties in the San
Joaquin Valley air basin: the San Joaquin Council of Governments,
the Stanislaus Council of Governments, the Merced County Association
of Governments, the Madera County Transportation Commission, the
Council of Fresno County Governments, Kings County Association of
Governments, the Tulare County Association of Governments and the
Kern Council of Governments.
---------------------------------------------------------------------------

    The Supplement identifies three categories of ammonia
(NH3) emission sources in the SJV, which are estimated to
account for 96% of ammonia air emissions in the Valley--farming
operations, including confined animal facilities (239.2 tpd),
evaporation from agricultural fertilizers (66.1 tpd), and composting
solid waste operations (20.5 tpd) (see Supplement at 11). Information
presented in the Supplement then compares District rules for confined
animal facility (CAF) and composting operations to analogous
requirements in other areas and discusses water quality measures for
agricultural fertilizer application that may also reduce air emissions
(see generally Supplement at Attachment A).
    Farming operations: The Supplement states that the control measures
in SIP-approved Rule 4570 (Confined Animal Facilities, adopted 2010)
\49\ have a secondary benefit of limiting NH3 emissions and
have reduced ammonia emissions by more than 100 tpd (see Supplement at
A-2, citing Staff Report for June 2009 re-adoption of Rule 4570 (June
2009) at Appendix F). Rule 4570 is a work practice rule that requires
farmers to implement management practices (e.g., feed according to NRCS
guidelines, remove manure from corrals at least four times per year)
for different components of the CAF operation, such as feeding, milking
parlors, housing/bedding, manure management and land application. Rule
4570 applies to livestock operations, including dairy, beef, poultry
and swine, above certain size thresholds. The District assumes in its
RACM analysis that, for most control measures, the ammonia control
efficiencies are the same as the VOC control efficiencies. The District
compares Rule 4570 to livestock rules in seven other California air
districts, including the South Coast Air Quality Management District
(SCAQMD), Bay Area Air Quality Management District (BAAQMD), and the
Sacramento Metropolitan Air Quality Management District (SMAQMD). Based
on a review of the number of work practices required by the other
California rules, the District concludes that Rule 4570 is at least as
stringent as the air quality rules for livestock operations in these
other areas. In cases where the work practice standards in other rules
may be more stringent than the requirements in Rule 4570, the District
considers these measures beyond RACT or the emissions differences not
significant (see, e.g., Supplement at A-7, noting frequency of
mitigation requirements in South Coast Rule 223, adopted June 2, 2006).
---------------------------------------------------------------------------

    \49\ See 77 FR 2228 (January 17, 2012) (final rule approving
Rule 4570 into the California SIP).
---------------------------------------------------------------------------

    The Supplement also compares Rule 4570 to the Idaho Department of
Environmental Quality's (IDEQ) dairy ammonia permit by rule, adopted in
2009 (Idaho rule).\50\ While Rule 4570 is based on implementing a
certain number of BMPs in specific categories, the Idaho rule is based
on a ``points'' system, where each BMP is assigned a certain number of
points based on control effectiveness. The District states that Rule
4570 is more stringent than the Idaho rule based on Rule 4570's lower
applicability threshold (e.g., 500 milking cows v. 1,638 cows (@1,400
lbs) for free stall/flush dairies), more stringent requirements and
greater number of required mitigation measures (see Supplement at A-25
and A-29). The District also states that Rule 4570 is more stringent
regarding temporary suspension and substitution of mitigation measures,
and contains more stringent testing, monitoring and recordkeeping
requirements. It also states that Rule 4570 is more stringent because
it provides specific mitigation measures for various operations at
dairies, while the Idaho rule is based on what the District
characterizes as an ``arbitrary'' point system that does not guarantee
a specific degree of control (see Supplement at A-24 to A-29).\51\
---------------------------------------------------------------------------

    \50\ The Idaho rule requires dairy farms above specified
threshold numbers of cows or animal units to register with Idaho DEQ
and to implement industry best management practices (BMPs) to
control ammonia emissions. A list of BMPs is contained in the rule.
Each BMP is assigned a point value based on relative effectiveness
in reducing ammonia. Dairy farms must employ BMPs totaling 27
points. See Idaho Administrative Procedure Act (IDAPA) 58.01.01
Sections 760-764: Rules for the Control of Ammonia from Dairy Farms
(adopted March 30, 2007; amended May 8, 2009).
    \51\ Citing IDEQ's technical documentation for the Idaho rule,
the Supplement states that the Idaho rule's point system is
``arbitrary'' and that overall ammonia emission reductions from the
rule may not be substantial given the flexibility in the rule and
the absence of a direct correlation between the points required and
the amount of emission reductions achieved (see Supplement at A-25).
---------------------------------------------------------------------------

    Fertilizer application: The Supplement identifies fertilizer
application to crops as the second largest source of ammonia emissions
in the Valley and suggests that research to identify maximum efficiency
of nitrogen use for various crop types could lead to a reduction of
excess nitrogen in the soil that is susceptible to leaching and
volatilization. The Supplement also refers to a ``Regional Board
General Order'' issued by the Central Valley Regional Water Quality
Control Board as a control measure that has ``significantly reduced
losses of nitrogen compounds to the environment, including leaching of
nitrogen compounds to groundwater and air emissions such as ammonia and
nitrous oxide'' (Supplement at A-25 to A-27).\52\ The Supplement does
not, however, identify any state or local air pollution control measure
that limits ammonia emissions from fertilizer application operations.
---------------------------------------------------------------------------

    \52\ See Reissued Waste Discharge Requirements General Order for
Existing Milk Cow Dairies, California Regional Water Quality Control
Board Central Valley Region Order R5-2013-0122, October 3, 2013,
available at http://www.waterboards.ca.gov/centralvalley/board_decisions/adopted_orders/general_orders/r5-2013-0122.pdf
---------------------------------------------------------------------------

    Composting: The District compares its two SIP-approved composting
rules, Rule 4566 (Organic Water Materials, adopted in 2011) \53\ and
Rule 4565 (Biosolids, Animal Manure, and Poultry Litter Operations,
adopted in 2007),\54\ to analogous rules adopted by the SCAQMD, Rule
1133.3 (Emission Reductions from Greenwaste Composting Operations,
adopted in 2011) and Rule 1133.2 (Emission Reductions from Co-
Composting Operations, adopted in 2003). For this analysis, the
District assumes that ammonia control efficiencies achieved by these
rules are the same as the VOC

control efficiencies. In its comparison of Rule 4566 with SCAQMD Rule
1133.3, the District acknowledges that Rule 1133.3 has a much lower
size threshold for implementing most stringent controls (80% control
efficiency) but notes that neither SCAQMD nor the District currently
has any facilities that trigger the most stringent controls. Therefore,
the District states that, in practice, the controls are equivalent. In
its comparison of Rule 4565 with SCAQMD Rule 1133.2, the District finds
that the controls in Rule 4565 are generally more stringent than Rule
1133.2 for small facilities but less stringent than Rule 1133.2 for
large facilities. The Supplement states that the most stringent
measures in Rule 1133.2 are not cost-effective for facilities in the
Valley.
---------------------------------------------------------------------------

    \53\ See 77 FR 71129 (November 29, 2012) (final rule approving
Rule 4566 into California SIP).
    \54\ See 77 FR 2228 (January 17, 2012) (final rule approving
Rule 4565 into California SIP).
---------------------------------------------------------------------------

3. Evaluation and Proposed Action
    The process followed by the District in the 2012 PM2.5
Plan and Supplement to identify RACM/RACT is generally consistent with
the EPA's recommendations in the General Preamble. The process included
compiling a comprehensive list of potential controls measures for
sources of direct PM2.5, NOX, SO2, and
ammonia in the SJV. This list included measures suggested in public
comments on the Plan. See 2012 PM2.5 Plan, Appendices C, D,
and I. No source categories were identified as insignificant except by
implication for a few source categories of ammonia which collectively
contributed less than 5 percent to the base year ammonia inventory
(Supplement, p. A-1.) As part of this process, the District evaluated
potential controls for all relevant source categories for economic and
technological feasibility and provided justifications for the rejection
of certain identified measures. Id. After completing this evaluation,
the District included enforceable commitments to adopt and
expeditiously implement those measures it found to be reasonable. See
2012 PM2.5 Plan, Table 5-3, p. 21 and Table D-1 above. Since
submittal of the 2012 PM2.5 Plan in March 2013, the District
has adopted all but two of these measures. One measure, amendments to
Rule 4905 (Natural Gas-Fired, Fan Type Residential Central Furnaces) is
scheduled for adoption this winter. The second measure, amendments to
Rule 4692 (Commercial Charbroiling), is not scheduled until 2016.
Research and development of cost-effective control technology are
currently underway for certain measures in Rule 4692, the addition of
PM2.5 emission limits for under-fired charbroilers (Plan, p.
5-22 and Supplement, p. 8).
    We have reviewed the District's determination in the 2012
PM2.5 Plan that its stationary and area source control
measures represent RACM/RACT for direct PM2.5,
NOX, and SO2. As discussed in Section II.C. of
the TSD, the EPA is proposing to determine that at this time, VOCs do
not contribute significantly to ambient PM2.5 levels that
exceed the 2006 PM2.5 standard in the SJV and that a VOC
control evaluation therefore is not necessary for purposes of this
standard in this area.\55\ In our review, we relied mainly on our
previous evaluations of the District's rules in connection with our
approval of the SJV RACT SIP for the 1997 8-hour ozone standard, our
comments on the 2012 PM2.5 Plan, and our comments on the
District's RACT SIP for the 2008 8-hour ozone standard.\56\ We also
reviewed measures suggested by the public in comments on the 2012
PM2.5 Plan. Based on this review, we believe that the
District's rules provide for the implementation of RACM/RACT for
stationary and area sources of direct PM2.5, NOX,
and SO2.\57\
---------------------------------------------------------------------------

    \55\ VOC sources in the San Joaquin Valley are currently subject
to a broad range of controls measures adopted by the District and
CARB as part of their strategy to attain the ozone standards in the
area. The SJV is currently designated nonattainment and classified
as extreme for the 1-hour ozone standard and for both the 1997 and
2008 8-hour ozone standards. See 40 CFR 81.305. Extreme ozone
nonattainment areas are required by CAA section 172(c)(1) to
implement RACM for VOC sources and by section 182(b)(2) to the
implement RACT for all major sources of VOC and certain other
sources of VOC. A major source of VOC in an extreme ozone
nonattainment area is a source that emits or has the potential to
emit 10 tons per year or more of VOC (CAA section 182(e)) which is
much lower than the 100 tpy threshold for major stationary sources
in Moderate PM2.5 nonattainment areas (CAA section
302(j)). In 2012, the EPA approved the RACM demonstration in SJV's
SIP for attainment of the 1997 8-hour ozone standard (77 FR 12652,
12670 (March 1, 2012)) and found that the State had met the section
182(b)(2) RACT control requirement for the 1997 8-hour ozone
standards (limited approval, 77 FR 1417 (January 10, 2012); final
corrective rule approval, 77 FR 71129 (November 29, 2012)).
    As noted in the General Preamble, Congress recognized that PM
precursors may be otherwise controlled and expressly recommended
that the EPA consider other provisions of the CAA in addressing
precursors (General Preamble at 13542, n. 22). Accordingly, the
General Preamble provides that a state may demonstrate in a SIP
submittal that control of VOC under other CAA requirements relieves
it from the need to adopt additional controls for VOC as a precursor
under section 189(e). Id. at 13542.
    \56\ See 77 FR 1417 (January 10, 2012); EPA Region 9, Technical
Support Document for EPA's Notice of Proposed Rulemaking for the
California State Implementation Plan--EPA's Evaluation of San
Joaquin Valley Unified Air Pollution Control District's Reasonably
Available Control Technology (RACT) Demonstration for Ozone State
Implementation Plan (SIP), Adopted April 16, 2009 (dated August 29,
2011); letter dated October 19, 2012, from Kerry Drake, Associate
Director, Air Division EPA-Region 9 to Samir Sheikh, SJVAPCD; and
letter dated June 4, 2014, from Andrew Steckel, Chief, Rules Office,
EPA Region 9 to Errol Villegas, Planning Manager, SJVAPCD.
    \57\ A full list of the District's rules, including cites to our
most recent final or proposed rulemaking on each can be found in
Appendix B to the TSD.
---------------------------------------------------------------------------

    We have also reviewed the District's analysis of current and
potentially available ammonia controls for the three largest sources of
ammonia emissions in the SJV: CAF operations, agricultural fertilizer
application, and composting operations. Collectively these sources
account for 96 percent of total base year (2007) ammonia emissions.\58\
See 2012 PM2.5 Plan, Appendix B, Table B-5.
---------------------------------------------------------------------------

    \58\ The balance of the ammonia inventory is spread among a
number of source categories from electric utilities to gasoline-
powered on-road vehicles. The largest of these sources, at 6.3 tpd
in 2007 (1.7 percent of the total ammonia inventory), is the area
source category ``Other (Miscellaneous Processes).'' See 2012
PM2.5 Plan, Appendix B, Table B-5. Ammonia emissions in
this category are from domestic sources including pets, untreated
human waste (e.g., diapers), and perspiration. See ENVIRON
International Corporation, ``Final Work Plan California Regional
PM10/PM2.5 Air Quality Study--Ammonia
Emissions Improvement Projects in Support of CRPAQS Aerosol Modeling
and Data Analyses: Draft Ammonia Inventory Development,'' April 13,
2001, p. 2-16, found at http://www.arb.ca.gov/ei/areasrc/nh3environworkplan.pdf.
    We note that two of the remaining source categories (open
burning and residential wood burning at a combined 2.9 tpd in 2007)
are covered by SIP-approved rules that prohibit and/or curtail
burning and therefore also reduce ammonia emissions from these
sources.
---------------------------------------------------------------------------

    Farming Operations and Composting: The District adopted Rule 4565,
Rule 4566 and Rule 4570 primarily to control VOC emissions, and EPA has
determined that the control requirements in each of these rules
represent RACT-level controls for VOCs. See 77 FR 2228 (January 17,
2012) (final rule approving Rule 4565 and Rule 4570 into California
SIP) and 77 FR 71129 (November 29, 2012) (final rule approving Rule
4566 into California SIP). Although the Supplement does not provide a
detailed analysis of the extent to which these rules also reduce
ammonia emissions, the District's general conclusion that the work
practice standards in these rules reduce ammonia emissions appears to
be factually correct. The District's evaluation of Rule 4565, Rule 4566
and Rule 4570 generally supports a conclusion that these SIP-approved
rules for CAFs and composting operations are as stringent as analogous
rules implemented in other California districts.
    With respect to the Idaho rule, because it is based on a point
system and Rule 4570 is based on numbers of BMPs for different
components of the CAF operation, it is difficult to compare the
requirements in these two rules

directly. Both rules contain options for controlling ammonia emissions
in different parts of the CAF operation, but Rule 4570 may be more
prescriptive in requiring a certain number of BMPs for each component,
while the Idaho rule does not set a specific number of BMPs and instead
requires that the points associated with the selected BMPs total to at
least 27. It appears that in some respects Rule 4570 has more stringent
provisions than the Idaho rule (e.g., rule applicability threshold, and
provisions for temporary suspension/substitution, testing and records
retention). On the other hand, the Idaho rule contains options (e.g.,
chemical amendments, lagoon nitrification/de-nitrification systems,
lagoon covers, tunnel ventilation with biofilter, incorporation of
manure within 24 hours of land application) that do not appear to be
included in Rule 4570. It is not clear whether these control options
are commonly implemented in Idaho or reasonably available or
appropriate for use in the SJV.
    In the absence of specific information regarding more stringent
ammonia air emission control measures that may be technologically and
economically feasible for implementation in the SJV area, we find the
District's evaluation of Rule 4565, Rule 4566 and Rule 4570 in
comparison to analogous rules adopted elsewhere is adequate to
demonstrate that the District is implementing all available control
measures for ammonia emissions from CAFs and composting operations that
are technologically and economically feasible for implementation in the
SJV at this time. We note, however, that the District's analyses of
these rules appear to rest on certain assumptions concerning ammonia
emissions reductions that are not supported by specific documentation
or analyses (e.g., assumptions concerning ammonia control efficiencies
based on VOC control efficiencies). The point system in the Idaho rule
appears to be based upon detailed scientific studies on the ammonia
control efficiencies of the identified BMPs,\59\ some of which may be
available for implementation in the SJV. We note also that the timing
of the NRDC decision in early 2013 may have constrained the State's and
District's ability to fully evaluate additional ammonia control
measures as part of a RACM/RACT control strategy ahead of the
applicable Moderate area attainment date (December 31, 2015). Taking
these unique circumstances into account, we find the District's ammonia
control evaluation adequate for RACM/RACT purposes at this time but
recommend that the State and District conduct a more thorough
evaluation of all available ammonia control measures for farming and
composting operations as part of its development of a Serious area
plan. Specifically, we encourage the District to revisit its control
evaluation for CAFs and composting operations at its earliest
opportunity, both to specifically consider the ammonia control
efficiencies and cost effectiveness of Rule 4565, Rule 4566 and Rule
4570, and to address any additional control options that may be
technologically and economically feasible for implementation in the
SJV, e.g., the BMPs identified in the Idaho rule and other control
options identified by EPA or by citizens during the District's
rulemaking processes.
---------------------------------------------------------------------------

    \59\ IDEQ's technical documentation indicates that under the
Idaho rule, BMP points are awarded based on a detailed assessment of
each BMP's relative effectiveness in controlling ammonia emissions.
See IDEQ, ``Scientific Basis for the Control of Ammonia from Dairy
Farms Best Management Practices,'' July 18, 2006, available at
http://www.deq.idaho.gov/media/635665-58_0101_0502_scientific_basis_final.pdf.
---------------------------------------------------------------------------

    Fertilizer application: Although certain water pollution control
and other requirements contained in the ``Regional Board General
Order'' cited in the Supplement may indirectly reduce ammonia emissions
to the air from fertilizer application operations, these requirements
have not been approved into the SIP for purposes of attainment of the
NAAQS and therefore cannot provide a basis for approval of a RACM
demonstration under the CAA. We are not aware, however, of ammonia air
emission control measures that have been adopted and implemented for
fertilizer application operations elsewhere. In the absence of
information regarding air emission control measures for agricultural
fertilizer application that may be technologically and economically
feasible for implementation in the SJV area, we find the District's
analysis in the Supplement acceptable for RACM purposes at this time.
We note also that the timing of the NRDC decision in early 2013 may
have constrained the State's and District's ability to fully evaluate
additional ammonia control measures as part of a RACM/RACT control
strategy ahead of the applicable Moderate area attainment date
(December 31, 2015). Taking these unique circumstances into account, we
find the District's ammonia control evaluation adequate for RACM/RACT
purposes at this time, but we encourage the District to revisit its
control evaluation for fertilizer application at its earliest
opportunity to specifically evaluate the technical and economic
feasibility of potential air pollution control measures that may reduce
ammonia emissions from fertilizer application in the SJV.
    Mobile Sources: Finally, we have reviewed the analysis of current
and potentially available controls for both on and off-road mobile
sources in Chapter 5 and Appendix C. As we have noted in previous
actions on SJV plans,\60\ California is a leader in the development and
implementation of stringent control measures for on-road and off-road
mobile sources. Its current program addresses the full range of mobile
sources in the SJV through regulatory programs for both new and in use
vehicles and through incentive grant programs. See 2012
PM2.5 Plan, Table 5-2 and Appendix A of the TSD. The
District has also adopted measures to reduce emissions from mobile
sources including its indirect source review rule (Rule 9510) and
employer trip reduction rule (Rule 9410) and has a well-funded
incentive grants program focused on mobile sources. See Chapter 6. The
MPOs also have a program to fund cost-effective TCMs. See Appendix C,
p. C-33. Overall, we believe that the State, District, and MPO programs
provide for the implementation of RACM for PM2.5 and its
precursors from mobile sources in the SJV.
---------------------------------------------------------------------------

    \60\ The proposed approvals of the SJV 2007 [8-hour] Ozone Plan
at 76 FR 57846, 57852 (September 16, 2011) and the 2008
PM2.5 Plan at 76 FR 41338, 41345 (July 13, 2011) include
discussions of California's control programs for mobile sources.
---------------------------------------------------------------------------

    For the foregoing reasons, we propose to find that the 2012
PM2.5 Plan and Supplement provide for the implementation of
all RACM/RACT that can be implemented prior to the applicable Moderate
area attainment date as required by CAA sections 189(a)(1)(C) and
172(c)(1) and to approve the RACM/RACT demonstration in the Plan.\61\
---------------------------------------------------------------------------

    \61\ The 2012 PM2.5 Plan is the latest in a series of
air quality plans and control strategies that the District and CARB
have adopted to provide for attainment of the NAAQS in the SJV.
These plans include the 2003 PM10 Plan (approved 69 FR
30005 (May 26, 2004)); the 2004 Extreme [1-hour] Ozone Attainment
Plan (approved 75 FR 10420 (March 8, 2010), approval withdrawn 77 FR
70376 (November 26, 2012)); the 2007 [8-hour] Ozone Plan (approved
77 FR 12652 (March 1, 2012)); the 2008 PM2.5 SIP
(approved 76 FR 69896 (November 9, 2011)); and the 2009 RACT SIP
(limited approval January 10, 2012 (77 FR 1417); last corrective
rule approval November 29, 2012 (77 FR 71129)).
---------------------------------------------------------------------------

E. Major Stationary Source Control Requirements Under CAA Section
189(e)

    CAA section 189(e) specifically requires that the control
requirements applicable to major stationary sources of

direct PM2.5\62\ also apply to major stationary sources of
PM2.5 precursors, except where the Administrator determines
that such sources do not contribute significantly to PM2.5
levels that exceed the standard in the area (General Preamble at 13539
and 13541 to 42). The Supplement contains a discussion of the
District's Rule 2201 (New and Modified Stationary Source Review Rule)
(Supplement at 17-20) and three potential major stationary sources of
ammonia operating in the SJV (Supplement at A-39 to A-41). The EPA is
not proposing to act on these components of the Plan at this time and
will do so in a separate rulemaking to address the control requirements
specific to major stationary sources of direct PM2.5 and
PM2.5 precursors under section 189(e) in the SJV.
---------------------------------------------------------------------------

    \62\ The control requirements applicable to major stationary
sources of direct PM2.5 in a Moderate area include, at
minimum, the requirements of a nonattainment new source review
(NNSR) permit program meeting the requirements of CAA section
172(c)(5) (see CAA 189(a)(1)(A)).
---------------------------------------------------------------------------