Federal Register: November 22, 2010 (Volume 75, Number 224)

DOCID: fr22no10-19 FR Doc 2010-29235

ENVIRONMENTAL PROTECTION AGENCY

Treasury Department

CFR Citation: 40 CFR Part 52

EPA ID: [EPA-R09-OAR-2009-0366; FRL-9229-3]

NOTICE: Part III

DOCID: fr22no10-19

DOCUMENT ACTION: Proposed rule.

SUBJECT CATEGORY:

Approval and Promulgation of Implementation Plans; State of California; 2007 South Coast State Implementation Plan for 1997 Fine Particulate Matter Standards; 2007 State Strategy; PM[ihel2].[ihel5]

DATES: Any comments must arrive by January 21, 2011.

DOCUMENT SUMMARY:

EPA is proposing to approve in part and disapprove in part State implementation plan (SIP) revisions submitted by the State of California to provide for attainment of the 1997 annual and 24hour PM2.5 national ambient air quality standard (NAAQS) in the Los AngelesSouth Coast Air Basin area (South Coast nonattainment area). The submitted SIP revisions are contained in the South Coast 2007 Air Quality Management Plan (South Coast 2007 AQMP) and portions of the 2007 State Strategy as revised in 2009. Specifically, EPA is proposing to approve the emissions inventories as meeting the requirements of the Clean Air Act (CAA) and EPA's fine particulate implementing regulations. EPA is also proposing to approve commitments to propose specific measures and meet specific aggregate emissions reductions by the South Coast Air Quality Management (District) and the California Air Resources Board (CARB) because the commitments strengthen the SIP. Finally, EPA is proposing to approve the air quality modeling demonstration as meeting the requirements of the CAA and EPA guidance. EPA is proposing to disapprove the attainment demonstration because it does not provide sufficient emissions reductions from adopted and EPA approved measures to provide for attainment of the NAAQS. As a result, EPA is also proposing to disapprove the reasonably available control measures/reasonably available control technology (RACM/RACT) and reasonable further progress (RFP) demonstrations and proposing not to grant California's request to extend to April 5, 2015 the deadline for the South Coast nonattainment area to attain the 1997 PM2.5 NAAQS because these requirements are linked to approving the attainment demonstration under the 1997 PM2.5 implementation rule. We are also proposing to disapprove the assignment of 10 tpd of NOX to the federal government. Finally, EPA is proposing to disapprove PM2.5 contingency measures and the motor vehicle emissions budgets (budgets) for the area's RFP years and attainment year. To the extent that the State can remedy the shortfall in emissions reductions for the attainment demonstration, which is the basis for the proposed disapproval of the attainment demonstration, EPA believes that many of the noted deficiencies could be addressed.

SUMMARY:

Environmental Protection Agency

SUPPLEMENTAL INFORMATION

Throughout this document, ``we,'' ``us'' and ``our'' refer to EPA.
Table of Contents
I. The PM2.5 NAAQS and the South Coast PM2.5 Nonattainment Area
II. California's State Implementation Plan Submittals to Address PM2.5 Attainment in the South Coast Nonattainment Area

A. California's SIP Submittals

1. 2007 South Coast AQMP

2. 2007 State Strategy

3. Additional SIP Submittal Related to Motor Vehicle Emissions Budgets (Budgets)

B. CAA Procedural and Administrative Requirements for SIP Submittals
III. CAA and Regulatory Requirements for PM2.5 Attainment SIPs
IV. Review of the South Coast 2007 AQMP and the South Coast Portion of the Revised 2007 State Strategy

A. Summary of EPA's Proposed Actions

B. Emission Inventories

1. Requirements for Emission Inventories

2. Emission Inventories in the South Coast 2007 AQMP

3. Proposed Action on the Emission Inventories

C. Reasonably Available Control Measures (RACM)/Reasonably Available Control Technology (RACT) and Adopted Control Strategy

1. Requirement for RACM/RACT

2. RACM/RACT Demonstration in the SIP

a. District's RACM/RACT Analysis and Adopted Control Strategy

b. CARB's RACM Analysis and Adopted Control Strategy

c. The Local Jurisdiction's RACM Analysis

3. Proposed Actions on RACM/RACT Demonstration and Adopted Control Strategy

D. Attainment Demonstration

1. Requirements for Attainment Demonstration

2. Air Quality Modeling in the South Coast 2007 AQMP

3. PM2.5 Precursors Addressed in the South Coast 2007 AQMP

4. Extension of the Attainment Date
[[Page 71295]]

5. Attainment Demonstration

a. Enforceable Commitments

i. The Commitments Do Not Represent a Limited Portion of Required Reductions

ii. The State Is Capable of Fulfilling Its Commitment

iii. The Commitment Is for a Reasonable and Appropriate Period of Time

b. Federal Reductions

6. Proposed Action on the Attainment Demonstration

E. Reasonable Further Progress Demonstration

1. Requirements for RFP

2. RFP Demonstration in the South Coast 2007 AQMP

3. Proposed Action on the RFP Demonstration

F. Contingency Measures

1. Requirements for Contingency Measures

2. Contingency Measures in the South Coast 2007 AQMP

3. Proposed Action on the Contingency Measures

G. Motor Vehicle Emissions Budgets for Transportation Conformity

H. MidCourse Review
V. EPA's Proposed Actions

A. EPA's Proposed Approvals and Disapprovals

B. CAA Consequences of a Final Disapproval
VI. Statutory and Executive Order Reviews
I. The PM[bdi2].[bdi5] NAAQS and the South Coast PM[bdi2].[bdi5] Nonattainment Area

On July 18, 1997 (62 FR 36852), EPA established new national ambient air quality standards (NAAQS) for PM2.5, particulate matter with a diameter of 2.5 microns or less, including annual standards of 15.0 [mu]g/m\3\ based on a 3year average of annual mean PM2.5 concentrations, and 24hour (or daily) standards of 65 [mu]g/m\3\ based on a 3year average of the 98th percentile of 24hour concentrations. 40 CFR 50.7 EPA established the standards based on substantial evidence from numerous health studies demonstrating that serious health effects are associated with exposures to
PM2.5 concentrations above the levels of these standards.

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, as well as new evidence for more subtle indicators of cardiovascular health. Individuals particularly sensitive to PM2.5 exposure include older adults, people with heart and lung disease, and children. See, EPA, Air Quality Criteria for Particulate Matter, No. EPA/600/P99/002aF and EPA/600/P99/002bF, October 2004.

PM2.5 can be emitted directly into the atmosphere as a solid or liquid particle (``primary'' or ``direct PM2.5'') or can be formed in the atmosphere as a result of various chemical reactions from precursor emissions of nitrogen oxides (NOX), sulfur dioxide (SO2), volatile organic compounds (VOC) and ammonia (NH3) (``secondary PM2.5''). See 72 FR 20586, 20589 (April 25, 2007)

Following promulgation of a new or revised NAAQS, EPA is required by CAA section 107(d) to designate areas throughout the United States as attaining or not attaining the NAAQS. On January 5, 2005, EPA published initial air quality designations for the 1997
PM2.5 NAAQS, based on air quality monitoring data for three year periods of 20012003 or 20022004. (70 FR 944). These designations became effective on April 5, 2005.

EPA designated the ``Los AngelesSouth Coast Air Basin'' area (South Coast nonattainment area), including Orange County, the southwestern twothirds of Los Angeles County, southwestern San Bernardino County, and western Riverside County as nonattainment for both the 1997 24hour and the annual PM2.5 standards. The South Coast PM2.5 nonattainment area is home to about 17 million people, has a diverse economic base, and contains one of the highestvolume port areas in the world. For a precise description of the geographic boundaries of the South Coast PM2.5 nonattainment area, See 40 CFR 81.305.\1\ The local air district with primary responsibility for developing a plan to attain the PM2.5 NAAQS in this area is the South Coast Air Quality Management District (District).
\1\ On October 17, 2006, EPA strengthened the 24hour
PM2.5 NAAQS by lowering the level to 35 [mu]g/m\3\. At the same time, we retained the level of the annual PM2.5 standard at 15.0 [mu]g/m\3\. 71 FR 61144. On November 13, 2009, EPA designated areas, including the South Coast, with respect to the revised 24hour NAAQS. 74 FR 58688. California is now required to submit an attainment plan for the 35 [mu]g/m\3\ standards by December 14, 2012. In this preamble, all references to the PM2.5 NAAQS, unless otherwise specified, are to the 1997 24hour PM2.5 standards of 65 [mu]g/m\3\ and annual standards of 15 [mu]g/m\3\.

Ambient annual PM2.5 levels in the South Coast are among the highest recorded in the United States at 18.8 [mu]g/m\3\ for the 20072009 period.\2\ In the South Coast, the levels and composition of PM2.5 differ by geographic location, with higher PM2.5 concentrations typically occurring in metropolitan Los Angeles and in the inland valley areas of San Bernardino and metropolitan Riverside Counties. The higher PM2.5 concentrations in Los Angeles County are mainly due to secondary formation of particulates. See South Coast 2007 AQMP, pages 213. \2\ See the Air Quality Subsystem (AQS) Preliminary Design Value Report dated August 26, 2010 in the docket for today's action. 18.8 [mu]g/m\3\ is the highest design value in the South Coast
nonattainment area. The design value is the three year average of annual means of a single monitoring site. (See 40 CFR 50 Appendix N Section 1(c)(1)).
II. California's State Implementation Plan Submissions to Address PM[bdi2].[bdi5] Nonattainment in the South Coast Nonattainment Area

A. California's SIP Submittals

Designation of an area as nonattainment starts the process for a state to develop and submit to EPA a State implementation plan (SIP) under title 1, part D of the CAA. This SIP must include, among other things, a demonstration of how the NAAQS will be attained in the nonattainment area as expeditiously as practicable, but no later than the date required by the CAA. Under CAA section 172(b), a State has up to three years after an area's designation to nonattainment to submit its SIP to EPA. For the 1997 PM2.5 NAAQS, these nonattainment SIPs were due no later than April 5, 2008.

California has made several SIP submittals to address PM2.5 nonattainment in the South Coast nonattainment area. The two principal ones are the District's 2007 PM2.5 Plan (South Coast 2007 AQMP) and the CARB's State Strategy for California's 2007 State Implementation Plan (2007 State Strategy).

1. 2007 South Coast AQMP

On November 28, 2007, the California Air Resources Board (CARB or State) submitted the ``Final 2007 Air Quality Management Plan, June 2007.'' \3\ This Plan was adopted by the District on June 1, 2007 and submitted to CARB on October 24, 2007.\4\ The South Coast
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2007 AQMP includes a PM2.5 attainment demonstration for the South Coast. In order to meet relevant CAA requirements for the PM2.5 NAAQS, the South Coast 2007 AQMP includes base and projected year PM2.5 emissions inventories for the South Coast nonattainment area; air quality monitoring data; short, medium and longterm District control measures; a summary of CARB's control measures; transportation control measures (TCMs); a demonstration of RFP; a modeled attainment demonstration; a demonstration of RACM/RACT; contingency measures for the 1997 PM2.5 RFP and for attainment for the South Coast PM2.5 nonattainment area; and a request to extend the attainment date for the 1997 PM2.5 NAAQS to April 5, 2015.\5\ The South Coast 2007 AQMP submittal also includes District Governing Board Resolution 079 adopting the final South Coast 2007 AQMP. The South Coast 2007 AQMP also contains documentation of the District's public process, including written responses to all public comments received.
\3\ The South Coast 2007 AQMP is the first South Coast Plan to address PM2.5. We have previously acted on numerous South Coast air quality plans for ozone, PM10, carbon monoxide, and NO2, such as the 1997/1999 AQMP. We approved the ozone portion of the 1997 South Coast AQMP, as amended in 1999, on April 10, 2000 (See 65 FR 18903). Our most recent action on a SIP addressing the CAA requirements for the South Coast ozone
nonattainment area was our partial approval and partial disapproval of the 2003 AQMP (See 74 FR 10176, March 10, 2009). Because the District prepares integrated plans that address multiple pollutants, and also controls VOC and NOX as precursors to
PM2.5, we will refer to control measures and control measure commitments from the 2003 AQMP further in this notice. \4\ See November 28, 2007 letter to Wayne Nastri, Regional Administrator, EPA Region 9, from James N. Goldstene, Executive Officer, CARB, with enclosures.
\5\ While the attainment date for PM2.5 areas with a full fiveyear extension would be April 5 2015, reductions must be implemented by 2014 to achieve attainment by that date. See 40 CFR 51.1007(b). We refer, therefore, to 2014 as the ``attainment year'' and April 5, 2015 as the ``attainment date.''

2. 2007 State Strategy

To demonstrate attainment, the South Coast 2007 AQMP relies in part on measures in the 2007 State Strategy. The 2007 State Strategy was adopted by CARB on September 27, 2007 and submitted to EPA on November 16, 2007.\6\ It discusses CARB's overall approach to addressing, in conjunction with local plans, attainment of both the 1997
PM2.5 and 8hour ozone NAAQS not only in the South Coast nonattainment area but also in California's other nonattainment areas such as the San Joaquin Valley and the Sacramento area. It also includes CARB's commitments to propose 15 defined State measures\7\ and to obtain specific amounts of aggregate emissions reductions of direct PM2.5, NOX, VOC and SOX in the South Coast from sources under the State's jurisdiction, primarily on and offroad motor vehicles and engines.
\6\ See CARB Resolution No. 0728, September 27, 2007 with attachments and letter from James N. Goldstene, Executive Officer, CARB, to Wayne Nastri, Regional Administrator, EPA Region 9, November 16, 2007 with enclosures.
\7\ The 2007 State Strategy also includes measures to be implemented by the California Bureau of Automotive Repair (Smog Check improvements) and the California Department of Pesticide Regulation (VOC reductions from pesticide use). See 2007 State Strategy, p. 6465 and CARB Resolution 728, Attachment B, p. 8.

On August 12, 2009, CARB submitted the ``Status Report on the State Strategy for California's 2007 State Implementation Plan (SIP) and Proposed Revision to the SIP Reflecting Implementation of the 2007 State Strategy'', dated March 24, 2009, adopted April 24, 2009 (``2009 State Strategy Status Report''),\8\ which updates the 2007 State Strategy to reflect its implementation during 2007 and 2008. \8\ See CARB Resolution No. 0934, April 24, 2009 and letter, James N. Goldstene, Executive Officer, CARB to Wayne Nastri, Regional Administrator, EPA Region 9, August 12, 2009 with enclosures. Only pages 1127 of the 2009 State Strategy Status Report are submitted as a SIP revision. The balance of the report is for informational purposes only. See Attachment A to CARB Resolution No. 0934.

In today's proposal, we are evaluating only those portions of the 2007 State Strategy as revised in 2009 \9\ that are relevant for attainment of the 1997 PM2.5 standards in the South Coast. \9\ We will also refer to the 2007 State Strategy as revised in 2009 as the ``revised 2007 State Strategy.''
3. Additional SIP Submittal Related to Motor Vehicle Emissions Budgets (Budgets)

In addition to the SIP submittals for the 1997 PM2.5 NAAQS mentioned above, on April 4, 2008, the District Governing Board approved an alternative approach for transportation conformity motor vehicle emission budgets for the South Coast nonattainment area. This new approach was based on the 2007 SIP baseline emissions reflecting only the regulations adopted as of October 2006 for all milestone years up to the attainment years. The CARB Governing Board approved Resolution 0827 itemizing the modifications to the South Coast nonattainment area transportation conformity emission budgets. The revised PM2.5 motor vehicle emissions budgets were submitted as an amendment to the California SIP on April 30, 2008. We are acting on those budgets today.
B. CAA Procedural and Administrative Requirements for SIP Submittals

CAA sections 110(a)(1) and (2) and 110(l) require a 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 a public hearing was held consistent with EPA's implementing regulations in 40 CFR 51.102.

Both the District and CARB have satisfied applicable statutory and regulatory requirements for reasonable public notice and hearing prior to adoption and submittal of the South Coast 2007 AQMP. The District conducted public workshops, provided public comment periods, and held public hearings prior to the adoption of the South Coast 2007 AQMP on June 1, 2007 (District Governing Board Resolution No. 079). CARB provided the required public notice and opportunity for public comment prior to its September 27, 2007 public hearing on the plan. See CARB Resolution No. 0741.

CARB conducted public workshops, provided public comment periods, and held a public hearing prior to the adoption of the 2007 State Strategy on September 27, 2007. (CARB Resolution No. 0728). CARB also provided the required public notice, opportunity for public comment, and a public hearing prior to its April 24, 2009 adoption of the 2009 State Strategy Status Report. See CARB Resolution 0934, April 24, 2009.

The SIP submittals include proof of publication for notices of the District and CARB public hearings, as evidence that all hearings were properly noticed. We therefore find that the submittals meet the procedural requirements of CAA sections 110(a) and 110(l).

CAA section 110(k)(1)(B) requires EPA to determine whether a SIP submittal is complete within 60 days of receipt. This section also provides that any plan that EPA has not affirmatively determined to be complete or incomplete will become complete 6 months after the date of submittal by operation of law. EPA's SIP completeness criteria are found in 40 CFR part 51, Appendix V.

The South Coast 2007 AQMP became complete by operation of law on May 28, 2008. The November 16, 2007 submission of the 2007 State Strategy and the 2009 revisions to the Strategy became complete by operation of law on May 16, 2008 and February 12, 2010, respectively. III. CAA and Regulatory Requirements for PM[bdi2].[bdi5] Attainment SIPs

EPA is implementing the PM2.5 NAAQS under Title 1, Part D, subpart 1 of the CAA, which includes section 172, ``Nonattainment plan provisions.'' Section 172(a)(2) establishes the attainment date for a PM2.5 nonattainment area ``as expeditiously as practicable'' but no later than five years after the area's designation as nonattainment. This section also allows EPA to grant up to a five year extension of an area's attainment date based on the severity of the area's nonattainment and
[[Page 71297]]
the availability and feasibility of controls. EPA designated the South Coast as a nonattainment area effective April 5, 2005, and thus the applicable attainment date is no later than April 5, 2010 or, should EPA grant a full fiveyear extension, no later than April 5, 2015.

Section 172(c) contains the general statutory planning requirements applicable to all nonattainment areas, including the requirements for emissions inventories, RACM/RACT, attainment demonstrations, RFP demonstrations, and contingency measures.

On April 25, 2007, EPA issued the Clean Air Fine Particle Implementation Rule for the 1997 PM2.5 NAAQS. 72 FR 20586, codified at 40 CFR part 51, subpart Z (PM2.5 implementation rule). The PM2.5 implementation rule and its preamble address the statutory planning requirements for emissions inventories, RACM/RACT, attainment demonstrations including air quality modeling requirements, RFP demonstrations, and contingency measures. This rule also addresses other matters such as which PM2.5 precursors must be addressed by the State in its PM2.5 attainment SIP, applicable attainment dates, and the requirement for midcourse reviews.\10\ We will discuss each of these CAA and regulatory requirements for attainment plans in more detail below.
\10\ In June 2007, a petition to the EPA Administrator was filed on behalf of several public health and environmental groups requesting reconsideration of four provisions in the
PM2.5 implementation rule. See EarthJustice, Petition for Reconsideration, ``In the Matter of Final Clean Air Fine Particle Implementation Rule,'' June 25, 2007. These provisions are (1) the presumption that compliance with the Clean Air Interstate Rule satisfies the NOX and SO2 RACT requirements for electric generating units; (2) the deferral of the requirement to establish emission limits for condensable particulate matter (CPM) until January 1, 2011; (3) revisions to the criteria for analyzing the economic feasibility of RACT; and (4) the use of out ofarea emissions reductions to demonstrate RFP. These provisions are found in the PM2.5 implementation rule and preamble at 2062320628, 40 CFR 51.1002(c), 2061920620, and 20636,
respectively. On May 13, 2010, EPA granted the petition with respect to the fourth issue. Letter, Gina McCarthy, EPA, to David Baron and Paul Cort, Earthjustice, May 13, 2010. EPA is currently considering the other issues raised in the petition.

Neither the District nor the State relied on the first, third, or fourth of these provisions in preparing the South Coast 2007 AQMP or 2007 State Strategy. The District has deferred CPM limits in its rules. EPA does not believe that this deferral adversely affects the Plan's RACT or expeditious attainment demonstrations. See section II.D.3 of the TSD for this proposal. EPA will evaluate any rule adopted or revised by the District after January 1, 2011 to assure that it appropriately addresses CPM.
IV. Review of the South Coast 2007 AQMP and the South Coast Portion of the 2007 State Strategy

A. Summary of EPA's Proposed Actions

EPA is proposing to approve in part and disapprove in part those portions of the South Coast 2007 AQMP and those portions of the 2007 State Strategy as revised in 2009 specific to the 1997 PM2.5 NAAQS in the South Coast. We are proposing to approve the base year and baseline emissions inventories in these SIP revisions as meeting the applicable requirements of the CAA and the PM2.5 implementation rule. We are also proposing to approve the District's and CARB's commitments to propose specific measures and to meet specific aggregate emissions reductions in these revisions as strengthening the SIP, as well as the District's air quality modeling demonstration as meeting the applicable requirements of the CAA and EPA guidance.

We are proposing to disapprove the attainment demonstration, RACM/ RACT analysis, RFP demonstration, and California's request to extend the attainment date to 2015 as not meeting the applicable requirements of the CAA and the PM2.5 implementation rule because they are dependent on the approval of the attainment demonstration (See 40 CFR 51.1009 and 51.1010). For the attainment demonstration, we are proposing to approve the air quality modeling, but we are proposing to disapprove the overall demonstration because it relies too extensively on commitments to emissions reductions in lieu of fully adopted and submitted rules. Rules that have either not been adopted in final form or have not been submitted to EPA cannot be credited toward the attainment demonstration. We are proposing to disapprove the motor vehicle emissions budgets for the RFP milestone years and the attainment year, because they are derived from RFP and attainment demonstrations which we are proposing to disapprove. Finally, we are proposing to disapprove the RFP and attainment contingency measures as not meeting the applicable requirements of the CAA and the PM2.5 implementation rule. To the extent that the State can remedy the shortfall in emissions reductions for the attainment demonstration, which is the basis for the proposed disapproval of the attainment demonstration, EPA believes that many of the noted deficiencies could be addressed.

EPA's analysis and findings are summarized below and are described in more detail in the technical support document (TSD) for this proposal, which is available on line at http://www.regulations.gov in the docket for this proposal (EPAR09OAR20090366), or from the EPA contact listed at the beginning of this notice.
B. Emissions Inventories

1. Requirements for Emissions Inventories

CAA section 172(c)(3) requires states to submit a ``comprehensive, accurate, current inventory of actual emissions from all sources of the relevant pollutant.'' The PM2.5 implementation rule requires states to include direct PM2.5 emissions and emissions of all PM2.5 precursors in this inventory, even if it has determined that control of any of these precursors is not necessary for expeditious attainment. 40 CFR Sec. 51.1008(a)(2) and 72 FR 20586, at 20648. Direct PM2.5 includes condensable particulate matter. See 40 CFR 51.1000. PM2.5 precursors are NOX, SO2, VOC, and ammonia (NH3).\11\ Id. The inventories should meet the data requirements of EPA's Consolidated Emissions Reporting Rule (codified at 40 CFR part 51 subpart A) and include any additional inventory information needed to support the SIP's attainment demonstration and (where applicable) RFP
demonstration. 40 CFR 51.1008(a)(1) and (2).
\11\ The District controls sulfur oxides (SOX), which includes SO2, and considers the two terms interchangeable for emissions purposes. We will use SOX in this notice.

A baseline emission inventory is required for the attainment demonstration and for meeting RFP requirements. As determined on the date of designation, the base year for this inventory should be the most recent calendar year for which a complete inventory was required to be submitted to EPA. The baseline emission inventory for calendar year 2002 or other suitable year should be used for attainment planning and RFP plans for areas initially designated nonattainment for the PM2.5 NAAQS in 2005. 40 CFR 51.1008(b).

EPA has provided additional guidance for PM2.5 emission inventories in ``Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter NAAQS and Regional Haze Regulations,'' November 2005 (EPA454/R05001).

2. Emissions Inventories in the South Coast 2007 AQMP

The baseline planning inventories for direct PM2.5 and all PM2.5 precursors for the South Coast nonattainment area together with additional documentation for the inventories are found in [[Page 71298]]
Appendix III of the South Coast 2007 AQMP. Average annual day baseline inventories are provided for the years 2002, 2005 (the reference year for the air quality modeling) and for the years 2008, 2010, 2011, and 2014. The baseline inventories incorporate reductions from federal, state, and District measures adopted prior to 2007 (``baseline measures''). South Coast 2007 AQMP, page 31. The District also provided both summer and winter planning inventories for
PM2.5 and PM2.5 precursors. South Coast 2007 AQMP, Appendix III, page III123.

Table 1 is a summary of the average annual day inventories for directlyemitted PM2.5 and for the PM2.5 precursors NOX, VOC, and SOX for the baseline modeling year of 2005 and the targeted attainment year of 2014 from the South Coast 2007 AQMP (derived from Appendix A, Table A2). It is these inventories that provide the basis for the control measure analysis and the RFP and attainment demonstrations in the South Coast 2007 AQMP. Table 1South Coast Nonattainment Area Emissions Inventory Summary for PM[ihel2].[ihel5] and PM[ihel2].[ihel5] Precursors for the 2005 Baseline Year and 2014 Attainment Year [Annual average day emissions in tons per day] \a\ NOX VOC PM2.5 SOX NH3 Emissions inventory category
2005 2014 2005 2014 2005 2014 2005 2014 2005 2014 Stationary/Areawide Sources..... 87 71 259 260 58 63 22 17 75 68 Onroad Mobile Sources.......... 526 287 264 159 20 17 4 2 29 15 Offroad Mobile Sources......... 360 293 208 157 22 18 37 25 n/a n/a

Total....................... 972 650 731 566 101 98 63 45 104 83 \a\ Numbers may not add due to rounding.

As a starting point for the South Coast 2007 AQMP's inventories, the District used CARB's 2002 base year inventory. An example of this inventory and CARB's documentation for its inventories can be found in Appendices A and F, respectively, of the 2007 State Strategy. The 2002 inventory for the South Coast nonattainment area was projected to 2005 and future years using CARB's California Emission Forecasting and Planning Inventory System (CEFIS). South Coast 2007 AQMP, Appendix III, page III11. Both base year and baseline inventories use the current version of California's mobile source emissions model approved by EPA for use in SIPs, EMFAC2007 V2.3, for estimating onroad motor vehicle emissions. 73 FR 3464 (January 18, 2008). Offroad inventories were developed using the CARB offroad model. Ammonia emissions estimates were provided separately by the District.\12\
\12\ Electronic mail from Kathy Hsiao, SCAQMD to Wienke Tax, EPA Region 9, RE: NH3 numbers for SCAB, dated October 29, 2010. 3. Proposed Action on the Emission Inventories

We have reviewed the emissions inventories in the South Coast 2007 AQMP and the inventory methodologies used by the District and CARB for consistency with CAA requirements, the PM2.5 implementation rule, and EPA's guidance. We find that the base year and projected baseline year inventories are comprehensive, accurate, and current inventories of actual or projected emissions of PM2.5 and PM2.5 precursors in the South Coast nonattainment area as of the date of their submittal. We therefore propose to approve these inventories as meeting the requirements of CAA section 172(c)(3), the PM2.5 implementation rule and applicable EPA guidance. We provide more detail on our review of the inventories in section II.A. of the TSD for this proposal.
C. Reasonably Available Control Measures (RACM)/Reasonably Available Control Technology (RACT) and Adopted Control Strategy

1. Requirements for RACM/RACT

CAA section 172(c)(1) requires that each attainment plan ``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 national primary ambient air quality standards.'' EPA defines RACM as measures that a State finds are both reasonably available and contribute to attainment as expeditiously as practicable in its nonattainment area. Thus, what constitutes RACM/RACT in a PM2.5 attainment plan is closely tied to that plan's expeditious attainment demonstration. 40 CFR 51.1010; 72 FR 20586 at 20612. States are required to evaluate RACM/ RACT for direct PM2.5 and all of its attainment plan precursors. 40 CFR 51.1002(c).

For PM2.5 attainment plans, EPA is requiring a combined approach to RACM and RACT under subpart 1 of Part D of the CAA. Subpart 1, unlike subparts 2 and 4, does not identify specific source categories for which EPA must issue control technology documents or guidelines, or identify specific source categories for State and EPA evaluation during attainment plan development. 72 FR 20586, at 20610. Rather, under subpart 1, EPA considers RACT to be part of an area's overall RACM obligation. Because of the variable nature of the PM2.5 problem in different nonattainment areas, which may require States to develop attainment plans that address widely disparate circumstances, EPA determined that states should have flexibility with respect to RACT and RACM controls but also that in areas needing significant emission reductions to attain the standards, RACT/RACM controls on smaller sources may be necessary to reach attainment as expeditiously as practicable. 72 FR 20586, at 20612, 20615. Thus, under the PM2.5 implementation rule, RACT and RACM are those reasonably available measures that contribute to attainment as expeditiously as practicable in the specific nonattainment area. 40 CFR 51.1010; 72 FR 20586, at 20612. Specifically, the PM2.5 implementation rule requires that attainment plans include the list of measures the state considered and information sufficient to show that a state met all requirements for the determination of what constitutes RACM/RACT in the specific nonattainment area. 40 CFR 51.1010(a). In addition, the rule requires that the state, in determining whether a particular emissions reduction measure or set of measures must be adopted as
[[Page 71299]]
RACM/RACT, consider the cumulative impact of implementing the available measures and adopt as RACM/RACT any potential measures that are reasonably available considering technological and economic feasibility if, considered collectively, they would advance the attainment date by one year or more. Any measures that are necessary to meet these requirements that are not already either federally promulgated, part of the state's SIP, or otherwise creditable in SIPs must be submitted in enforceable form as part of a state's attainment plan for the area. 72 FR 20586, at 20614.

A more comprehensive discussion of the RACM/RACT requirement for PM2.5 attainment plans and EPA's guidance for it can be found in the PM2.5 implementation rule preamble at 20609 20633 and in section II.D. of the TSD for this proposal.

2. RACM/RACT Demonstration in the SIP

CARB and the District have rulemaking processes for development, adoption and implementation of RACM/RACT that have been in place for decades. Many of the measures being implemented in California and the South Coast nonattainment area are the most stringent in the nation and are often adopted for implementation in other areas. In addition, the State and District have adopted new measures since 2002, the base year for the South Coast 2007 AQMP, and included enforceable commitments for measures that are scheduled to be adopted in the future. The RACM/RACT analysis for the South Coast 2007 AQMP includes an evaluation of the State's, District's, and the Southern California Association of Governments' (SCAG's) new stationary, area and mobile sources measures that have been adopted since the base year and those that are being committed to for adoption in the future. See CARB Staff Report, ``Proposed 2007 State Implementation Plan for the South Coast Air BasinPM2.5 Annual Average and 8Hour ozone National Ambient Air Quality Standards'' (September 21, 2007); South Coast 2007 AQMP, Appendix VI; and 2007 State Strategy, Appendix G. A more detailed discussion of the District, State and SCAG measures is provided below. a. District's RACM/RACT Analysis and Adopted Control Strategy

The District's RACM/RACT analysis, which focuses on stationary and area source controls, is described in Chapter 6 and Appendix VI of the South Coast 2007 AQMP.

Since the 1970s, the District has adopted stationary source control rules that have resulted in significant improvement of air quality in the South Coast nonattainment area. When command and control rules were no longer within the limitations of economic efficiency, the District began using economic incentive approaches with programs such as the Regional Clean Air Incentives Market (RECLAIM) and the Carl Moyer program.\13\ While the District still relies on command and control regulations, the District's control strategies are now supplemented by market incentive and compliance flexibility approaches where appropriate. These regulations and strategies have yielded significant emissions reductions from sources under the District's jurisdiction. In developing the South Coast 2007 AQMP, the District conducted a process to identify RACM for the South Coast that involved public meetings to solicit input, evaluation of EPA suggested RACM and RACT, and evaluation of other air agencies' regulations. See South Coast 2007 AQMP, Appendix VI.
\13\ The Carl Moyer Memorial Air Quality Standards Attainment Program (``Carl Moyer Program'') provides incentive grants for engines, equipment and other sources of pollution that are cleaner than required, providing early or extra emission reductions. Eligible projects include cleaner onroad, offroad, marine, locomotive and stationary agricultural pump engines. The program achieves nearterm reductions in emissions of NOX, PM, and VOC or reactive organic gas (ROG) which are necessary for California to meet its clean air commitments under the SIP.

To determine which measures would be feasible for the South Coast, the District looked at measures implemented in other nonattainment areas' plans (including the San Joaquin Valley, the San Francisco Bay Area, Sacramento, Ventura, DallasFort Worth, the HoustonGalveston area, and by the Lake Michigan Air Directors Consortium, or LADCO), and held meetings with CARB, technical experts, local government representatives, and the public during development of the South Coast 2007 AQMP. The District sponsored an AQMP summit, which generated 200 potential control measures. In addition, the District reviewed the list of control measures in EPA's PM2.5 implementation rule. The District also reevaluated all 82 District rules and regulations. The District then screened the identified measures and rejected those that affected few or no sources in the South Coast, had already been adopted as rules, or were in the process of being adopted. The remaining measures were evaluated using baseline inventories, available control technologies, and potential emission reductions as well as whether the measure could be implemented on a schedule that would contribute to attainment of the PM2.5 standard assuming a 2015 deadline. South Coast 2007 AQMP, Appendix VI.

In general, EPA believes that the District's current rules and regulations are equivalent to or more stringent with respect to emissions of PM2.5 and PM2.5 precursors than those developed by other air districts, with a few exceptions where improvements are possible. The District is exploring several options for reducing emissions further. These include the feasibility of lowering emission limits and increasing levels of control in order to promote cleaner stationary source technologies; lowering the VOC content of coatings and solvents; establishing standards and test methods for generic equipment and lowering release or leak thresholds; improving leak detection, repair, inspection and maintenance; and adding best management practices to rules.

Based on its RACM/RACT evaluation for stationary and area sources under its jurisdiction, the District developed 37 stationary source control measures that contained all measures included in other districts' AQMPs, as well as some new innovative measures. The District determined that the few available measures that District staff did not include would not advance the attainment date or contribute to RFP due to the insignificant or unquantifiable emissions reductions they would potentially generate. Since submittal of the AQMP in 2007, the District has completed action on the majority of these rules and submitted them to EPA for approval into the SIP.

From October 2002 through June 2006, the District adopted approximately 17 rules to address its commitment to achieve the reductions committed to in the 2003 AQMP for the South Coast. These rules included controls on VOC emissions from refineries and chemical plants, cocomposting operations, architectural coatings, solvent cleaning operations, oil and gas production wells, and livestock waste. Many of the adopted rules achieved more estimated reductions in VOC, NOX and SOX than were expected in the 2003 AQMP. A summary of these rules, which are included in the baseline emissions estimates for the South Coast 2007 AQMP, is provided in Table 12 of the South Coast 2007 AQMP. See South Coast 2007 AQMP, Chapter 1, Table 12 and Chapter 4, page 46, and Table B1 in Appendix B of the TSD for today's action.

[[Page 71300]]

In addition to the rules adopted for 2003 AQMP, the District has also made new commitments in its South Coast 2007 AQMP to achieve further reductions from VOC, NOX, SOX and direct PM2.5 sources in the South Coast Area. The District committed to adopt and submit measures that will achieve the following additional emissions reductions: 32 tpd NOX, 10 tpd VOC, 4 tpd direct PM2.5 and 3 tpd SOX.\14\ See CARB Staff Report on the South Coast 2007 AQMP, page ES2 to ES4. The District expects to meet its emissions reductions commitments for each of the pollutants by adopting new control measures and programs found in the Table 42A of the South Coast 2007 AQMP (See South Coast 2007 AQMP, page 410 and CARB Staff Report on South Coast 2007 AQMP, p. 18) and from additional actions summarized in the CARB Staff Report on the South Coast 2007 AQMP (See CARB Staff Report on South Coast 2007 AQMP, p. 17). The new control measures and additional actions are estimated to achieve more of the District's NOX and VOC emission reduction commitments. They include new rules to regulate lubricants, consumer products, nonRECLAIM ovens, dryers and furnaces, space heaters, facility modernizations, livestock waste, residential wood burning, commercial cooking, and continuation of the Carl Moyer program. The South Coast 2007 AQMP also identifies 22 measures (beyond the new control measures and additional actions just discussed) for further review which may also yield additional reductions towards the District's commitments. As discussed above, the District's commitment is to achieve the estimated total tonnage reductions of each pollutant because specific control measures and actions as adopted may provide more or less reductions than estimated in the South Coast 2007 AQMP. \14\ CARB uses the term ROG (reactive organic gases) where we use the term VOC. We will use the term ``VOC'' in this notice to refer to both ROG and VOC.

Finally, EPA notes that since the adoption of the South Coast 2007 AQMP, the District has already adopted and submitted several new rules that help fulfill the District's enforceable commitments for additional emission reductions of NOX, VOC, direct PM2.5 and SOX in the South Coast area. Tables 2 and 3 below summarize the status of these new rules.
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Table 3Submittal and Approval Status of District Rules in the 2007 PM[ihel2].[ihel5] Plan Rule 445Woodburning fireplaces and SIPapproved........... 74 FR 27716, 6/11/09. wood stoves.
Rule 1144Vanishing oils and rust SIPapproved........... 75 FR 40726, 07/14/10. inhibitors.
Rule 1143Consumer Paint Thinners Not yet submitted New rule; no previous version approved into the and MultiPurpose Solvents. adopted 07/09/10. SIP; District is revising rule. Rule 1145Plastic, Rubber, Leather SIPapproved........... 75 FR 40726, 07/14/10. and Glass Coatings.
Rule 1147NOX reductions from SIPapproved........... 75 FR 46845, 08/04/10. miscellaneous sources.
Rule 2002Further SOX reductions Not yet adopted........ Most recent approval 08/29/06, 71 FR 51120. from RECLAIM.
Rule 1111Further NOX reductions SIPapproved........... 75 FR 46845, 08/04/10. from space heaters.
Rule 1110.2Liquid and gaseous SIPapproved........... 74 FR 18995, 4/27/09. fuelsstationary ICEs.
Rule 1146NOX from industrial, Submitted.............. Most recent approval04/08/02, 67 FR 16640. institutional, commercial boilers,
steam generators, and process
heaters.
Rule 1146.1NOX from small Submitted.............. Most recent approval09/06/95, 60 FR 46220. industrial, institutional,
commercial boilers, steam
generators, and process heaters.
Rule 1127Livestock Waste........... Submitted to EPA on 10/ Found complete on 10/25/06. 05/06.
Refinery Pilot Program............... Not yet adopted........ N/A. [[Page 71302]]
Rule 2301Indirect Source Review.... Not yet adopted........ N/A. Carl Moyer program................... No rule associated with Ongoing. this measure.
AB923 Light duty vehicle high emitter No rule associated with N/A. program. this measure.
AB923 Light duty vehicle high emitter No rule associated with N/A. program. this measure.

b. CARB's RACM Analysis and Adopted Control Strategy

Source categories for which CARB has primary responsibility for reducing emissions in California include most new and existing on and offroad engines and vehicles, motor vehicle fuels, and consumer products. In addition, California has unique authority under CAA section 209 (subject to a waiver by EPA) to adopt and implement new emission standards for many categories of onroad vehicles and engines, and new and inuse offroad vehicles and engines.

Given the need for significant emissions reductions from mobile and area sources to meet the NAAQS in California nonattainment areas, the State of California has been a leader in the development of some of the most stringent control measures nationwide for onroad and offroad mobile sources and the fuels that power them. These standards have reduced new car emissions by 99 percent and new truck emissions by 90 percent from uncontrolled levels. 2007 State Strategy, p. 37. The State is also working with EPA on goods movement activities and is implementing programs to reduce emissions from ship auxiliary engines, locomotives, harbor craft and new cargo handling equipment. In addition, the State has standards for lawn and garden equipment, recreational vehicles and boats, and other offroad sources that require newly manufactured equipment to be 8098% cleaner than their uncontrolled counterparts. Id. Finally, the State has adopted many measures that focus on achieving reductions from inuse mobile sources that include more stringent inspection and maintenance (I/M) or ``Smog Check'' requirements, truck and bus idling restrictions, and various incentive programs. Since 1994 alone, the State has taken more than 45 rulemaking actions and achieved most of the emissions reductions needed for attainment in the State's nonattainment areas. See 2007 State Strategy, pp. 3640. As is noted in the 2007 State Strategy, EPA has approved California's mobile source program as representing best available control measures. See 2007 State Strategy, Appendix G, 69 FR 5412 (February 4, 2004), 69 FR 30006 (May 26, 2004) (proposed and final approval of San Joaquin Valley PM10 plan).

CARB developed its proposed 2007 State Strategy after an extensive public consultation process to identify potential SIP measures.\15\ From this process, CARB identified and committed to propose 15 new defined measures. These measures focus on cleaning up the inuse fleet as well as increasing the stringency of emissions standards for a number of engine categories, fuels, and consumer products. Many, if not most, of these measures are being proposed for adoption for the first time anywhere in the nation. They build on CARB's already comprehensive program described above that addresses emissions from all types of mobile sources and consumer products, through both regulations and incentive programs. See Appendix A of the TSD. Table 4 below lists the new defined measures in the 2007 State Strategy that include one measure each from the California Bureau of Automotive Repair and the California Department of Pesticide Regulation.
\15\ More information on this public process including presentations from the workshops and symposium that proceeded the adoption of the 2007 State Strategy can be found at http:// www.arb.ca.gov/planning/sip/2007sip/2007sip.htm.
Table 42007 State Strategy Defined Measures Scheduled for Consideration and Current Status Primary area (SC and/or Defined state measure SJV) Adoption year Current status Smog Check Improvements............... Both..................... 20072008............... Elements approved 75 FR 38023 (July 1, 2010). Expanded Vehicle Retirement........... Both..................... 20082014............... Adopted CARB June 2009; Bureau of Automotive Repair September 2010. Revisions to Reformulated Gasoline Both..................... 2007.................... Approved, See 75 FR 26653 (May 2, 2010). Program.
Cleaner Inuse Heavy Duty Trucks...... Both..................... 2008.................... Adopted 2008, pending revisions. Auxiliary Ship Cold Ironing and Other SC....................... 20072008............... Adopted December 2007. Clean Technologies.
Cleaner Main Ship Engines and Fuels... SC....................... Fuel: 2007, Engines: Adopted July 2007. 2009. Port Truck Modernization.............. SC....................... 20072008............... Adopted December 2007 and December 2008. Accelerated Introduction of Cleaner Both..................... 20072008............... In progress. Locomotives.
Clean Up Existing Harbor Crafts....... SC....................... 2007.................... Adopted November 2007, revised June 2010. Cleaner InUse OffRoad Engines....... Both..................... 2007.................... Adopted 2007, pending revisions. Cleaner InUse Agricultural Equipment. SJV...................... 2009.................... In progress using incentive funds. New Emissions Standards for Both..................... 20092010............... Partial adoption, 2008; additional regulation in public Recreational Boats. review. [[Page 71303]]
Expanded OffRoad Recreational Vehicle Both..................... By 2010................. Adopted November 2008. Emissions Standards.
Enhanced Vapor Recovery for Above Both..................... 2007.................... Adopted June 2007. Ground Storage Tanks.
Additional Evaporative Emissions Both..................... By 2010................. Partial adoption, 2008. Standards.
Consumer Products Program (I & II).... Both..................... 2008 & 20102012........ Phase IApproved 74 FR 57074 (November 4, 2009). Department of Pesticide Regulation.... SJV...................... 2008.................... Adopted 2008, amended 2009. SC = South Coast nonattainment area; SJV = San Joaquin Valley. Source: 2009 State Strategy Status Report, p. 23 (footnotes in original not included).

Appendix A of the TSD includes a list of all measures adopted by CARB between 1990 and the beginning of 2007. These measures, reductions from which are reflected in the South Coast 2007 AQMP's baseline inventories, fall into two categories: Measures that are subject to a waiver of Federal preemption under CAA section 209 (``section 209 waiver measures'' or ``waiver measures'') and those for which the State is not required to obtain a waiver (``nonwaiver measures''). Emissions reductions from waiver measures are fully creditable in attainment and RFP demonstrations and may be used to meet other CAA requirements, such as contingency measures. See EPA's proposed approval of the San Joaquin Valley 1hour ozone plan at 74 FR 33933, 33938 (July 14, 2009) and final approval at 75 FR 10420 (March 8, 2010). The State's baseline nonwaiver measures have generally all been approved by EPA into the SIP and as such are fully creditable for meeting CAA requirements.

In addition to the State's commitments to propose defined new measures, the 2007 State Strategy includes enforceable commitments for direct PM2.5, NOX, VOC, and SOX emissions reductions from mobile source categories that are that are crucial for attainment of the PM2.5 NAAQS in the South Coast nonattainment area. For the South Coast nonattainment area, the revised 2007 State Strategy includes State commitments to achieve 152 tpd of NOX, 46 tpd of VOC, 9 tpd of direct PM2.5, and 20 tpd of SOX (See 2007 State Strategy, p. 63 and CARB Resolution 0728, Attachment B, p. 6). The 2007 State Strategy indicates that the State expects to achieve these emission reductions in the South Coast nonattainment area by the projected attainment year of 2014 from the measures listed in Table 4 or other similar measures. In the 2007 State Strategy, CARB provides an estimated emissions reduction for each measure to show that, when considered together, these measures can meet the total commitment. CARB states, however, that its enforceable commitment is to achieve the aggregate emissions reductions for each pollutant by the given dates and not for a specific level of reductions from any specific measure. See 2007 State Strategy, p. 58. A summary of the estimates from the proposed measures is provided in Table 5 below.

As mentioned above, CARB's commitment is also to propose specific new measures that are identified and defined in the 2007 Strategy State. See 2007 State Strategy, pp. 6465 and 2009 State Strategy revisions, pp. 2223. Table 5 below lists these defined measures. As shown in this table, the State has adopted many of the measures. Table 5Expected Emissions Reductions from Defined Measures in the 2007 State Strategy for the South Coast (2014 Tons per Day) 2014 Direct Measure 2014 NOX 2014 VOC PM2.5 2014 SOX Smog Check Improvements (BAR) [partial]......... 2.0 4.1 .............. .............. Modifications to Reformulated Gasoline Program.. .............. 4.4 .............. .............. Cleaner InUse HeavyDuty Trucks................ 59.7 5.0 3.5 .............. Ship Auxiliary Engine Cold Ironing & Clean 25.4 0.1 0.5 0.3 Technology.....................................
Cleaner Main Ship Engines and Fuel [fuel portion 1.3 .............. 1.9 17.0 only]..........................................
Clean Up Existing Harbor Craft.................. 2.4 0.1 0.1 .............. Cleaner InUse OffRoad Equipment (> 25hp)...... 10.5 2.7 2.6 .............. Consumer Products Program [partial]............. .............. 1.8 .............. ..............
Totals.......................................... 101.3 18.2 8.6 17.3 Source: 2009 CARB Staff Report on the State Strategy, p. 5. Only defined measures with reductions in the South Coast nonattainment area are shown here.

c. The Local Jurisdiction's RACM Analysis

The local jurisdiction's RACM analysis was conducted by the metropolitan planning organization (MPO) for the South Coast region, the Southern California Association of Governments (SCAG). This analysis, which focused on transportation control measures (TCMs), and its results are described in Appendix IVC of the South Coast 2007 AQMP. The TCMs in the South Coast 2007 AQMP are derived from TCM projects in the 2006 SCAG Regional Transportation Improvement Program (RTIP). This evaluation, described beginning on page 49 of Appendix IV C of the South Coast 2007 AQMP, resulted in extensive local government commitments to implement
[[Page 71304]]
programs to reduce auto travel and improve traffic flow. South Coast 2007 AQMP page 66 and Appendix IVC. SCAG also provided reasoned justifications for any measures that it did not adopt. Attachment A to Appendix IVC contains an extensive list of TCMs in process and newly programmed TCMs. The enforceable commitment from SCAG and the transportation agencies was to fund and implement projects in the first two years of the 2006 Regional Transportation Improvement Program (RTIP).
3. Proposed Actions on RACM/RACT and Adopted Control Strategy

Under the PM2.5 implementation rule, RACM/RACT are the set of measures necessary for expeditious attainment. The measures must address emissions of PM2.5 and all PM2.5 attainment plan precursors that are necessary to result in such expeditious attainment. In order for a PM2.5 plan to demonstrate that it provides for RACM/RACT, it must also demonstrate that it provides for expeditious attainment. 72 FR 20586, p. 20612 20623. As discussed further below in section D.5., we are proposing to disapprove the PM2.5 attainment demonstration for the South Coast nonattainment area because it relies too heavily on commitments to reduce emissions in lieu of fully adopted measures. Absent an approvable attainment demonstration, we are unable to propose to approve and must instead propose to disapprove the AQMP's RACM/RACT demonstration. It appears, however, that the District, State and local jurisdictions have identified and otherwise provided for the implementation of a comprehensive set of measures that are among the most stringent in the nation and, should the State correct the deficiencies in the attainment demonstration, we expect to be able to propose to approve the plan's RACM/RACT demonstration.

Because they will strengthen the California SIP, we are proposing to approve the District's commitments to the adoption and
implementation schedule for specific control measures given in Table 7 3 in the South Coast 2007 AQMP, to the extent that these commitments have not yet been fulfilled, and to achieve specific aggregate emissions reductions of direct PM2.5, NOX, VOC, and SOX by specific years as given in Table 410 of the South Coast 2007 AQMP.

We are also proposing to approve, as a SIP strengthening measure, CARB's commitments to propose certain defined measures, as given on page 23 of the 2009 State Strategy Status Report, to achieve aggregate emissions reductions of 152 tpd NOX, 46 tpd VOC, 9 tpd PM2.5, and 20 tpd SOX in the South Coast by 2014. D. Attainment Demonstration

1. Requirements for Attainment Demonstrations

CAA section 172 requires a State to submit a plan for each of its nonattainment areas that demonstrates attainment of the applicable ambient air quality standard as expeditiously as practicable but no later than the specified attainment date. Under the PM2.5 implementation rule, this demonstration should consist of four parts: (1) Technical analyses that locate, identify, and quantify sources of emissions that are contributing to violations of the
PM2.5 NAAQS;
(2) analyses of future year emissions reductions and air quality improvement resulting from alreadyadopted national, State, and local programs and from potential new State and local measures to meet the RACT, RACM, and RFP requirements in the area;
(3) adopted emissions reduction measures with schedules for implementation; and
(4) contingency measures required under section 172(c)(9) of the CAA.

See 40 CFR 51.1007; 72 FR 20586, at 20605.

The requirements for the first two parts are described in the sections on emissions inventories and RACM/RACT above and in the sections on air quality modeling, PM2.5 precursors, extension of attainment date, and attainment demonstrations that follow immediately below. Requirements for the third and fourth parts are described in the sections on the control strategy and the contingency measures, respectively.

2. Air Quality Modeling in the South Coast 2007 AQMP

The procedures for modeling attainment of the PM2.5 NAAQS as part of an attainment SIP are contained in EPA's ``Guidance on the Use of Models and Other Analyses for Demonstrating Attainment of Air Quality Goals for the 8Hour Ozone and PM2.5 NAAQS and Regional Haze.'' \16\ A brief description of the modeling used to support South Coast's attainment demonstration follows. For more detailed information about the modeling, please refer to the TSD associated with this rulemaking, which can be found in the docket for today's action.
\16\ The guidance is available at http://www.epa.gov/ttn/scram/ guidance_sip.htm and in the docket for today's action.

Air quality modeling is used to establish emission attainment targets, a combination of emissions of PM2.5 and PM2.5 precursors that the nonattainment area can accommodate without exceeding the NAAQS, and to assess whether the proposed control strategy will result in attainment of the NAAQS by the applicable attainment date. Air quality modeling is performed for a base year and compared to air quality monitoring data to determine model performance. Once the performance is determined to be acceptable, future year emission inventory changes are simulated to determine the relationship between emission reductions and changes in ambient air quality throughout the nonattainment area.

The attainment demonstration for the South Coast nonattainment area is based on the CAMx model using the ``one atmosphere'' approach comprised of the carbon bond IV (CBIV) gas phased chemistry and a static twomode particle size aerosol.\17\ CAMx annual average PM2.5 modeling simulations were generated for 2005 and 2014 baseline emissions scenarios and for a 2014 controlled emissions scenario by the District. District staff compared the base year model output to speciated particulate data measured in 2005 as part of the Multiple Air Toxics III (MATESIII) program. Model specifications, such as boundary conditions, domain size, and resolution, meet EPA criteria and are discussed in the TSD. Model performance for total mass (the sum of specific individual species), as well as specific individual species, is adequate and is discussed in the TSD.
\17\ CAMx is the Comprehensive Air Quality Model with
extensions, an Eulerian photochemical dispersion model that allows for integrated ``oneatmosphere'' assessments of gaseous and particulate air pollution (ozone, PM2.5, PM10, air toxics) over many scales ranging from suburban to continental.

The District's attainment analysis follows EPA's guideline technique of applying componentspecific relative response factors (RRF) to monitored data throughout the South Coast nonattainment area. A RRF is the ratio of the model's future to current (baseline) predictions at a monitor. Future PM2.5 concentrations are estimated at existing monitoring sites by multiplying a modeled RRF at the grid cell locations of each monitor by the observationbased, monitorspecific, ``baseline'' design value. A separate RRF is calculated for each of the PM2.5 precursors. Future PM2.5 design values were estimated by District staff at existing monitoring sites throughout the South Coast nonattainment area by multiplying modeled RRFs for each
[[Page 71305]]
monitor times the observed ``componentspecific design value''. The future PM2.5 design values were then compared to the annual and 24hour NAAQS to demonstrate attainment at each site. The maximum 2014 predicted 24hour PM2.5 design value at any site is 56.6 [mu]g/m\3\; this is lower than the 24hour PM2.5 NAAQS at 65 [mu]g/m\3\. The maximum 2014 predicted PM2.5 annual design value is 15.0 [mu]g/m\3\; a predicted design value of 15.04 [mu]g/m\3\ or lower is considered modeled attainment of the annual standard.

EPA guidance also recommends the use of supplemental data analyses to support the air quality modeling. The District used air quality trends and emission inventory trends as ``weight of evidence'' to support the air qualit

FOR FURTHER INFORMATION CONTACT

Wienke Tax, Air Planning Office (AIR- 2), U.S. Environmental Protection Agency, Region IX, (415) 9474192, tax.wienke@epa.gov

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