The EPA Regional Administrator, Jared Blumenfeld signed the following rule on September 30, 2015 and EPA 

is submitting it for publication in the Federal Register (FR). While we have taken steps to ensure the accuracy of this 

version of this rule, it is not the official version. Please refer to the official version in a forthcoming FR publication 

appearing on the Government Printing Office website, http://fdsys.gpo.gov/fdsys/search/home.action, and on 

www.regulations.gov in Docket Number EPA-R09-OAR-2015-0204.

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R09-OAR-2015-0204; FRL- ]

Approval and Promulgation of Implementation Plans; Designation 

of Areas for Air Quality Planning Purposes; California; South 

Coast 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 standards (NAAQS) in the Los Angeles-South 

Coast Air Basin (South Coast) Moderate PM2.5 nonattainment area.

These SIP revisions are the 2012 PM2.5 Plan, submitted February 

13, 2013, and the 2015 Supplement, submitted March 4, 2015. The 

EPA is also proposing to reclassify the South Coast PM2.5

nonattainment area, including reservation areas of Indian 

Country and any other area of Indian Country within it where the 

EPA or a tribe has demonstrated that the tribe has jurisdiction,

as a Serious nonattainment area for the 2006 PM2.5 NAAQS based on 

EPA’s determination that the area cannot practicably attain this 
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September 30, 2015. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

2

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 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 [Federal Register Office: 

insert date 30 days after date of publication in the Federal 

Register].

ADDRESSES: Submit comments, identified by docket number EPA-R09-

OAR-2015-0204, by one of the following methods:

 Federal eRulemaking Portal: www.regulations.gov. 

Follow the on-line instructions.

 E-mail: tax.wienke@epa.gov.

 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 
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3

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 e-mail. 

The www.regulations.gov website 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 e-mail directly to the EPA, your e-mail 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-2015-

0204) for this proposed rule is available electronically on the 

www.regulations.gov website 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 
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September 30, 2015. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

4

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, (415) 

947-4192, tax.wienke@epa.gov

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 South Coast 2012 PM2.5 Plan and 2015 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
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G. Demonstration that Attainment by the Moderate Area Attainment 

Date is Impracticable

H. Reasonable Further Progress and Quantitative Milestones

I. Contingency Measures

J. Motor Vehicle Emission Budgets

K. General Conformity Budgets

V. Proposed Reclassification as Serious Nonattainment and 

Serious Area SIP Requirements

VI. Reclassification of Reservation Areas 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 standards (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 (μg/m3) to 35 μg/m3 (40 

CFR 50.13).

1 Epidemiological studies have shown statistically 

 

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 μg/m3 based on 

a 3-year average of annual mean PM2.5 concentrations and 24-hour (daily) 

standards of 65 μg/m3 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 μg/m3 (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 μg/m3 codified at 40 CFR 50.13.
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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

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 South Coast as nonattainment 

for the 2006 PM2.5 standard of 35 μg/m3 (74 FR 58688, November 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.
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2009). This designation became effective on December 14, 2009

(40 CFR 81.305). The South Coast area is also designated 

nonattainment for the 1997 annual and 24-hour PM2.5 standards.3 On 

June 2, 2014, the EPA classified the South Coast area as 

Moderate nonattainment for both the 1997 PM2.5 standards and the 

2006 PM2.5 standard under subpart 4 of part D, title I of the Act 

(79 FR 31566).

The South Coast PM2.5 nonattainment area is home to about 17 

million people, has a diverse economic base, and contains one of 

the highest-volume 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. 

Ambient PM2.5 levels in the South Coast have declined 

considerably in the past 15 years to levels just above the 2006 

PM2.5 NAAQS. For the 2011-2013 period, the 24-hour PM2.5 design 

value for the area, based on monitored readings at the Mira Loma

monitor, is 36 ug/m3.

4

 

3 See 70 FR 944 (January 5, 2005) and 40 CFR 81.305. In November 2007, 

California submitted the 2007 PM2.5 Plan to provide for attainment of the 1997 

PM2.5 standards in the South Coast. In November 2011, the EPA approved all but 

the contingency measures in the 2007 PM2.5 Plan (76 FR 69928, November 9, 

2011). In November 2011 and April 2013, the State submitted a revised 

contingency measure plan, which the EPA approved on October 29, 2013 (78 FR 

64402, October 29, 2013). 

4 See EPA, Air Quality System Report dated September 28, 2015 in the docket 

for today’s action. “Design value” means the calculated concentration 

according to the applicable appendix of 40 CFR part 50 for the highest site 

in an attainment or nonattainment area (40 CFR 58.1).
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The local air district with primary responsibility for 

developing a plan to attain the 2006 PM2.5 NAAQS in this area is 

the South Coast Air Quality Management District (District or 

SCAQMD). The District works cooperatively with the California 

Air Resources Board (CARB) in preparing these plans. Authority

for regulating sources under state jurisdiction in the South 

Coast 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.

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 
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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

In March of 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.

California had three years from the December 14, 2009 

effective date of the South Coast’s designation as nonattainment 

for the 2006 PM2.5 standard to submit a SIP for the South Coast

that addressed the applicable requirements of the Act.

7 On 

December 19, 2012, the District adopted the Final 2012 Air 

Quality Management Plan (AQMP), which addressed attainment of 

 

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)).

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.

7 See CAA section 172(b) and 40 CFR 51.1002(a).
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the 2006 PM2.5 NAAQS, among other CAA requirements. We refer 

herein to the portions of the 2012 AQMP that address attainment 

of the 2006 PM2.5 NAAQS as the ‘‘2012 PM2.5 Plan.’’ On January 25, 

2013, CARB adopted the 2012 PM2.5 Plan as an element of the 

California SIP and submitted it to the EPA on February 13, 2013.8

On January 4, 2013, several weeks after the District’s 

adoption of the Plan, the U.S. Court of Appeals for the D.C. 

Circuit issued its decision in a challenge to the EPA’s 2007 

PM2.5 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 4.9 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

 

8 See letter dated February 13, 2013, from James N. Goldstene, Executive 

Officer, CARB, to Jared Blumenfeld, Regional Administrator, EPA Region 9, , 

with attachments, and CARB Board Resolution 13-3.

9 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.
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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.’’

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.10

On February 6, 2015, the District adopted the ‘‘Supplement 

to the 24-Hour PM2.5 State Implementation Plan for the South 

Coast Air Basin’’ (‘‘2015 Supplement’’ or ‘‘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 March 4, 2015. The Supplement includes 

 

10 See 79 FR 69806, 69809 (November 21, 2013) and 79 FR 31566, 31568 (June 2, 

2014).
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information on the implementation of reasonably available 

controls for ammonia sources in the South Coast and the 

District’s demonstration that the 2012 PM2.5 Plan and 2015 

Supplement satisfy the requirements of subpart 4. As a 

consequence of the NRDC decision, we are reviewing the 2012 PM2.5

Plan and 2015 Supplement for compliance with the applicable 

requirements of both subpart 1 and subpart 4. 

The EPA provided its preliminary views on the CAA’s 

requirements for particulate matter plans under part D, title I 

of the Act in ‘‘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 attainment plans 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 
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[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).

Additionally, in a proposed rule published March 23, 2015 

(80 FR 15340), the EPA provided further interpretive guidance on 

the statutory SIP requirements that apply to areas designated 

nonattainment for the PM2.5 standards (hereafter “Proposed PM2.5

Implementation Rule”). We discuss these preliminary 

interpretations of the Act as appropriate in our evaluation of 

the 2012 PM2.5 Plan and 2015 Supplement in section IV of this 

proposed rule.

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,’’ submitted on February 13, 

2013, and the second is the 2015 Supplement, submitted on March 

4, 2015.

11,12

 

11 See footnote 8.

12 See Letter dated March 4, 2015 from Richard W. Corey, Executive Officer, 

California Air Resources Board, to Jared Blumenfeld, Regional Administrator 

EPA Region 9, with attachments, and CARB Resolution 15-3.
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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 

2012 PM2.5 Plan on December 7, 2012.13 CARB provided the required 

public notice and opportunity for public comment prior to its 

January 25, 2013 public hearing on the 2012 PM2.5 Plan.

14 The SIP 

submittal includes proof of publication of notices for these

public hearings. We find, therefore, that the 2012 PM2.5 Plan 

 

13 See 2012 PM2.5 Plan, Public hearing notices, SCAQMD Governing Board 

Resolution 12-19, “A Resolution of the South Coast Air Quality Management 

District (AQMD or District) Governing Board Certifying the Final Program 

Environmental Impact Report for the 2012 Air Quality Management Plan (AQMP), 

adopting the Draft final 2012 AQMP, to be referred to after Adoption as the 

Final 2012 AQMP, and to be submitted into the California State Implementation 

Plan,” December 7, 2012.

14 See CARB Resolution 13-3, “South Coast Air Basin 2012 PM2.5 and Ozone State 

Implementation Plans,” January 25, 2013.
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meets the procedural requirements for public notice and hearing 

in CAA sections 110(a) and 110(l).

The District adopted the 2015 Supplement after reasonable 

public notice and hearing.15 CARB adopted the Supplement for 

submittal as a SIP revision at its February 19, 2015 Board 

meeting after reasonable public notice.

16

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. A completeness review allows us to 

determine if the submittal includes all the necessary items and 

information we need to evaluate and act on it for substantive 

compliance with applicable requirements.

The February 13, 2013 submittal of the 2012 PM2.5 Plan 

became complete by operation of law on August 13, 2014. The 2015 

Supplement became complete by operation of law on September 4, 

2015 (see our Technical Support Document (TSD) at section I.B).

 

15 See Notice of Public Hearing to Adopt Supplemental Document to the 2012 

PM2.5 Plan for the 2006 PM2.5 Standard.

16 See CARB, Notice of Public Meeting to Consider a Minor Revision to the 

South Coast 2012 PM2.5 State Implementation Plan, and CARB Board Resolution 15-

2, February 19, 2015.
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IV. Review of the South Coast 2012 PM2.5 Plan and 2015 Supplement

We summarize our evaluation of the 2012 PM2.5 Plan and 2015 

Supplement below. Our detailed evaluation can be found in the 

TSD for this proposal which is available online at 

www.regulations.gov in docket number EPA-R09-OAR-2015-0204, on 

EPA Region 9’s website at 

http://www.epa.gov/region9/air/actions/southcoast/#PM25, 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 NAAQS, 

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.
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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. At the time the 2012 PM2.5 Plan and 2015 Supplement 

were developed, California was 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 submission 
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should include documentation explaining how the emissions 

projections were calculated. 

2. Emissions Inventories in the 2012 PM2.5 Plan

The annual average planning inventories for direct PM2.5 and 

all PM2.5 precursors (NOx, SOx, VOC, and ammonia) for the South 

Coast PM2.5 nonattainment area together with documentation for 

the inventories are found in Chapter 3 and Appendices III and V 

of the South Coast 2012 PM2.5 Plan and in Attachment A to the 

2015 Supplement. Additional inventory documentation specific to 

the air quality modeling is in Appendix V. Annual average 

inventories are provided for the 2008 base year, and for future 

years 2014 and the PM2.5 attainment year of 2015. (Additional 

years such as 2017, 2019, 2023 and 2030 are also provided, but 

these inventories are largely for the purposes of ozone 

attainment.) Baseline inventories reflect all control measures 

adopted by the District prior to June 2012 and by CARB prior to 

August 2011. Growth factors used to project these baseline 

inventories are derived mainly from data obtained from the 

Southern California Association of Governments (SCAG), the 

metropolitan planning organization (MPO) for the Los Angeles 

area (2012 PM2.5 Plan, page 3-1).
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Each inventory includes emissions from point, area, onroad, and non-road sources. Stationary sources include point and 

area sources. Point sources in the South Coast air basin that 

emit 4 tons per year or more of VOC, NOx, SOx or PM report 

annual emissions to the District. Point source emissions for the 

2008 base year emission inventory were based on emissions 

reported from the SCAQMD’s Annual Emissions Reporting Program.17

Area sources include smaller emissions sources distributed 

across the nonattainment area. CARB and the District estimate 

emissions for about 400 area source categories using activity 

information and emission factors. Activity data may come from 

national survey data or reports (e.g., from the DOE Energy 

Information Administration) or local sources such as the 

Southern California Gas Company, paint suppliers, and District 

databases. Emission factors can be based on a number of sources 

including source tests, compliance reports, and EPA’s AP-42.18

Emissions inventories are constantly being revised and 

improved. Between the finalization of the South Coast 2007 AQMP 

 

17 See http://www.aqmd.gov/home/regulations/compliance/annual-emissionreporting.

18 AP-42 is EPA’s Compilation of Air Pollutant Emission Factors, and has been 

published since 1972 as the primary source of EPA's emission factor 

information. It contains emission factors and process information for more 

than 200 air pollution source categories. A source category is a specific 

industry sector or group of similar emitting sources. The emission factors 

have been developed and compiled from source test data, material balance 

studies, and engineering estimates.
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and the development of the 2012 PM2.5 Plan, the District added new 

area source categories such as liquefied petroleum gas (LPG) 

transmission losses, storage tank and pipeline cleaning and 

degassing, and architectural colorants to the inventories in the 

2012 PM2.5 Plan. We provide more detail on these updates and 

revisions in section II.A. of the TSD. 

The on-road mobile inventories use EMFAC2011 for estimating 

motor vehicle emissions (2012 PM2.5 Plan, p. 3-1).19 Since 

EMFAC2011 was released in 2011, CARB has adopted additional 

regulations to control air pollution from mobile sources. For 

the 2012 PM2.5 Plan, the State adjusted EMFAC2011 emissions 

estimates for the advanced clean cars program, reformulated 

gasoline rules, and Smog Check program to reflect these new 

measures (2012 PM2.5 Plan, p. 3-5). Re-entrained paved road dust 

emissions were calculated using EPA’s AP-42 road dust 

methodology (2012 PM2.5 Plan, Appendix III, p. III-1-13 and 2015 

Supplement, Attachment B). SCAG, the MPO for the Los Angeles 

area, provided transportation activity data from the adopted 

2012 Regional Transportation Plan (RTP). 

Off-road emissions such as construction, mining, gardening 

and agricultural equipment emissions were calculated using 

 

19 EMFAC2011 was approved for use in SIPs and conformity on March 6, 2013 (see 

78 FR 14533).
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CARB’s 2011 In-Use Off-Road Fleet Inventory Model. The off-road 

equipment population was adjusted due to the recession, and 

equipment hours of use were adjusted based on reported activity. 

Equipment load factors were updated using a 2009 academic study 

and information provided by engine manufacturers. External 

adjustments were made to CARB’s off-road emissions estimates for 

locomotives, large-spark ignition engines, and nonagricultural 

internal combustion engines. CARB also calculated emissions from 

ocean-going vessels, commercial harbor craft, locomotives, and 

cargo handling equipment. Locomotive emissions reflect EPA 

regulations effective in 2008 and adjustments due to economic 

activity. The District estimated aircraft emissions. Future 

emissions forecasts are based largely on growth forecasts 

(demographic and economic information) from SCAG. 

A summary of the Plan’s 2008 base year inventory and the 

2014 projected inventory is provided in Table 1 below. For a 

more detailed discussion of the inventories, see the 2012 PM2.5

Plan, Appendix III.

Table 1. Summary of Emissions for the South Coast PM2.5 Nonattainment 

Area (annual average in tons per day)

2008 2014

Direct PM2.5

Stationary and Area 

Sources

48 50

On-Road Mobile 

Sources

19 12
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Table 1. Summary of Emissions for the South Coast PM2.5 Nonattainment 

Area (annual average in tons per day)

2008 2014

Off-Road Mobile 

Sources

13 8

Total 80 70

Nitrogen Oxides

Stationary and Area 

Sources

92 77

On-Road Mobile 

Sources

462 272

Off-Road Mobile 

Sources

204 157

Total 758 506

Sulfur Dioxide

Stationary and Area 

Sources

14 12

On-Road Mobile 

Sources

2 2

Off-Road Mobile 

Sources

38 4

Total 54 18

Volatile Organic Compounds

Stationary and Area 

Sources

257 234

On-Road Mobile 

Sources

209 117

Off-Road Mobile 

Sources

127 100

Total 593 451

Ammonia

Stationary and Area 

Sources

88.7 85.6

On-Road Mobile 

Sources

19.9 16.5

Off-Road Mobile 

Sources

0.1 0.1

Total 108.9 102.1
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Source: South Coast 2012 PM2.5 Plan, Chapter 3, Tables 3-2A, 

3-4A, Appendix III, Table III-1-5, and 2008 ammonia inventory 

from Appendix V, Table V-4-2.

3. Evaluation and Proposed Action

The emissions inventories in the 2012 PM2.5 Plan were made 

available to the public for comment and were subject to public 

hearing at both the District and State levels. See SCAQMD 

Governing Board Resolution 12-19, p. 3 and CARB Resolution 13-3, 

p. 4. 

The inventories in the South Coast 2012 PM2.5 Plan and 2015 

Supplement are based on the most current and accurate 

information available to the State and District at the time the 

2012 PM2.5 Plan and its inventories were being developed, 

including the latest EPA-approved version of California’s mobile 

source emissions model, EMFAC2011, and the EPA’s most recent AP42 methodology for paved road dust. The inventories 

comprehensively address all source categories in the South Coast 

and were developed consistent with the EPA’s inventory guidance. 

For these reasons, we are proposing to approve the 2008 base 

year emissions inventory in the 2012 PM2.5 Plan as meeting the 

requirements of CAA section 172(c)(3). We also propose to find 

that the baseline inventories in the Plan provide an adequate 
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basis for the reasonably available control measure (RACM), RFP,

and impracticability demonstrations in the 2012 PM2.5 Plan.

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, 

2015 Supplement, and July 28, 2015 letter include a 

demonstration that attainment by the Moderate attainment date is 

impracticable.

Air quality modeling is used to establish attainment 

emissions 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 performance is determined to be 

acceptable, future year changes to the emissions inventory are 

simulated with the model to determine the relationship between 
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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, Office of Air 

Quality Planning and Standards, EPA to Regional Air Program 

Managers, EPA (“Modeling Guidance Update”).20 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 projections by 

 

20 The EPA modeling guidance is 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/final03-pm-rh-guidance.pdf and

http://www.epa.gov/ttn/scram/guidance/guide/Update_to_the_24-

hour_PM25_Modeled_Attainment_Test.pdf.
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considering evidence other than the main air quality modeling 

attainment test.

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 implementation of the SIP 

control strategy (including RACM) does not result in attainment 

of the standard by the Moderate area attainment date. 

For an attainment demonstration, a thorough review of all 

modeling inputs and assumptions (including consistency with EPA 

guidance) is especially important, since the modeling must 

ultimately support a conclusion that the plan (including its 

control strategy) will provide for timely attainment of the 

applicable NAAQS. In contrast, for an impracticability 

demonstration, the end point is a reclassification to Serious, 

which triggers the requirement for a new Serious Area attainment 

plan with a new air quality modeling analysis, and a new control 

strategy. See CAA section 189(b)(1). Thus, the Serious Area 

planning process would provide an opportunity to refine the 

modeling analysis and/or correct any technical shortcomings in 

the impracticability demonstration. Therefore, the burden of 
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proof will generally be lower for an impracticability 

demonstration compared to an attainment demonstration. 

2. Air Quality Modeling in the 2012 PM2.5 Plan 

The 2012 PM2.5 Plan and 2015 Supplement contain a 

demonstration of attainment by the Moderate area attainment 

date, which is December 31, 2015. SCAQMD developed a modeling 

protocol for the 2012 PM2.5 Plan, which EPA reviewed during the 

District’s development of the Plan. The Plan discusses air 

quality modeling in Chapter 5, “Future Air Quality,” and in 

detail in Appendix V, “Modeling and Attainment Demonstrations.” 

The 2012 PM2.5 Plan’s attainment demonstration was based on 

photochemical modeling with the Community Multiscale Air Quality 

(CMAQ) model, using routinely available meteorological and air 

quality data as input. The 2012 PM2.5 Plan and the 2015 

Supplement contain an unmonitored area analysis as well as a 

weight of evidence (WOE) demonstration. The WOE demonstration in 

the 2015 Supplement accounts to some extent for the effect of 

the drought on ambient PM2.5 levels in the South Coast.

 In a letter dated July 28, 2015, the SCAQMD requested that 

EPA reclassify the South Coast Air Basin as Serious 

nonattainment for the 2006 24-hour PM2.5 NAAQS based on 

monitoring data indicating that attainment is not practicable by 
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the Moderate area attainment date, which is December 31, 2015.21

The SCAQMD also requested that the EPA treat the 2012 PM2.5 Plan 

and 2015 Supplement, together with the air quality data provided 

in the July 28, 2015 letter, as a demonstration that the area 

cannot practicably attain by the Moderate area attainment date. 

 Based on the request from the SCAQMD, the modeled 

attainment demonstration provided in the Plan, the 2015 

Supplement, and the monitoring data provided in the July 28, 

2015 letter, we are evaluating the State’s submittal as a 

demonstration that attainment by the Moderate area attainment 

date is impracticable. We provide a more detailed evaluation of 

the air quality modeling in the Plan in section II.B. of our 

TSD. 

3. Conclusion on Air Quality Modeling

Given the Plan’s extensive discussion of modeling 

procedures, tests, and performance analyses consistent with 

EPA’s guidance in the Modeling Protocol, and the good model 

performance, EPA finds that the modeling is adequate for 

purposes of supporting the RACM demonstration, the RFP 

 

21 See letter dated July 28, 2015, from Barry R. Wallerstein, Executive 

Officer, SCAQMD, to Elizabeth Adams, Acting Director, Air Division, US 

Environmental Protection Agency, Region 9.
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demonstration, and the demonstration of impracticability in the 

2012 PM2.5 Plan and Supplement.

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.

22

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.

23

The 2007 PM2.5 Implementation Rule contained rebuttable 

presumptions concerning the four PM2.5 precursors applicable to 

 

22 EPA, Air Quality Criteria for Particulate Matter (EPA/600/P-99/002aF,

October 2004), Chapter 3.

23 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. 
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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 

PM2.5 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)), 
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the court cited CAA section 189(e)

24

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 the 

state provides a demonstration adequate to rebut the

presumption for a particular precursor in a particular

nonattainment 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 

 

24 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.”
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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 mobiles 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, BACM and 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 to also determine, under appropriate circumstances, that 

regulation of certain PM2.5 precursors from other source

categories in a given nonattainment area is not necessary. For 
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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 PM2.5 levels in the 

nonattainment area.

25

We are evaluating the South Coast 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.

2. Evaluation of Precursors in 2012 PM2.5 Plan and 2015 

Supplement

The 2012 PM2.5 Plan and 2015 Supplement discuss the five 

primary pollutants that contribute to the mass of the ambient 

 

25 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).
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aerosol (i.e., ammonia, NOx, SOx, VOC, and directly emitted 

PM2.5), and states that various combinations of reductions in 

these pollutants could all provide a path to clean air.26 The 

Plan assesses and presents the relative value of each ton of 

precursor emission reductions, considering the resulting ambient 

microgram per cubic meter improvements in PM2.5 air quality.27 As 

presented in the weight of evidence discussion, trends of PM2.5

and NOx emissions suggest a direct response between lower 

emissions of PM2.5 and NOx and improved air quality. The CMAQ 

simulations in the Plan provide a set of response factors for 

direct PM2.5, NOx, SOx and VOCs, based on improvements to ambient 

24-hour PM2.5 levels resulting from reductions of each pollutant. 

The contribution of ammonia emissions is embedded as a component 

of the SOx and NOx factors since ammonium nitrate and ammonium 

sulfate are the resultant particulate species formed in the 

atmosphere. 

The 2012 PM2.5 Plan and 2015 Supplement describe how 

reductions in NOx, SO2, VOC and ammonia emissions contribute to 

 

26 2012 PM2.5 Plan, Appendix V, p. V-5-51 and Appendix V, Attachment 8, 

Relative Contributions of Precursor Emissions Reductions to Simulated 

Controlled Future-Year 24-hour PM2.5 Concentrations.

27 2012 PM2.5 Plan, Appendix V, Attachment 8, Relative Contributions of 

Precursor Emissions Reductions to Simulated Controlled Future-Year 24-hour 

PM2.5 Concentrations.
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attainment of the PM2.5 standard in the South Coast area and 

contain the District’s evaluation of available control measures 

for all four of these PM2.5 precursor pollutants, in addition to 

direct PM2.5, consistent with the regulatory presumptions under 

subpart 4. The 2015 Supplement also contains a discussion of the 

nonattainment New Source Review (NNSR) control requirements 

applicable to major stationary sources under CAA section 189(e) 

(see 2015 Supplement at Attachment E), which we are not 

addressing in this proposal.28 We discuss the state’s evaluation 

of potential control measures for direct PM2.5, NOx, SO2, VOC and 

ammonia in section IV.D of this rulemaking, ‘‘Reasonably 

Available Control Measures/Reasonably Available Control 

Technology.’’ 

D. Reasonably Available Control Measures/Reasonably Available 

Control Technology

1. Requirements for RACM/RACT

 

28 In a separate rulemaking to approve revisions to SCAQMD’s nonattainment New 

Source Review (NNSR) program, the EPA determined that the control 

requirements applicable under the SCAQMD SIP to major stationary sources of 

direct PM2.5 also apply to major stationary sources of NOx, SOx, and VOC, and 

that major stationary sources of ammonia do not contribute significantly to 

PM2.5 levels which exceed the PM2.5 standards in the area. See 80 FR 24821, May 

1, 2015. This rulemaking addressed the control requirements of CAA section 

189(e) only for NNSR purposes and not for attainment planning purposes under 

subpart 1 and 4 of part D, title I of the Act.
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The general subpart 1 attainment plan requirement for RACM 

and RACT is described in CAA section 172(c)(1), which requires

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.29 As part of the RACM/RACT 

 

29 This interpretation is consistent with guidance provided in the General 

Preamble at 13540.
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analysis, all available controls should be evaluated, and 

reasonable controls should be adopted.

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, onroad and non-road emission source that is technologically and 

economically feasible (General Preamble at 13540). 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). 

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).
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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 and 2015 Supplement

The 2012 PM2.5 Plan and 2015 Supplement’s RACM/RACT 

evaluation for direct PM2.5, NOx, VOC, ammonia, and SOx sources is 

presented in Appendix VI and in Attachment D to the 2015 

Supplement. SCAG’s RACM analysis for mobile sources is detailed 

in the 2012 PM2.5 Plan, Appendix IV-C (‘‘Regional Transportation 

Strategies and Control Measures’’). CARB’s RACM evaluation for 

mobile sources is included in Appendix VI of the 2012 PM2.5 Plan.

The evaluation of potential controls is presented by 

pollutant and then by rule type/source category. For stationary 

and area source categories, the comparison to recently-issued 

EPA CTGs is broken down by the current District rule or rules 
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that apply to that source category. See 2012 PM2.5 Plan, Appendix 

VI, and 2015 Supplement, Attachment D.

For the 2012 PM2.5 Plan, the District, CARB and SCAG each 

undertook a process to identify and evaluate potential measures 

that could contribute to expeditious attainment of the PM2.5

standards in the South Coast nonattainment area. We describe 

these processes below. 

The District conducted a multi-step process to identify 

candidate RACM measures for the South Coast 2012 PM2.5 Plan that 

are technologically and economically feasible. The first step 

was to conduct a 2012 Air Quality Technology Symposium in 

September of 2011. Technical experts from a wide variety of 

areas and the public were invited to provide new and innovative 

concepts to assist the South Coast area with attaining the PM 

and ozone NAAQS. The District also conducted ongoing outreach to 

engage stakeholders in the process. The following concepts were 

proposed as a result of these efforts:

 promote zero or near-zero emission technologies and 

provide incentives for mobile source and goods movement 

equipment upgrades,
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 further reduce VOC emissions from coatings, solvents, 

and various consumer products focusing on reformulations or 

alternatives to VOC-based solvents,

 conduct a technology review for NOx RECLAIM, and 

further reduce NOx emissions through the use of low NOx burners, 

fuel cells, biogas, and distributed power generation, 

 address energy-climate change and co-benefits, the 

need for electricity storage, or new fossil-fueled peaking 

plants, to compensate for fluctuation in renewable energy 

supply, and use outreach to promote energy efficiency, influence 

consumer behavior, expand carpools, increase gas taxes, and 

promote multiagency collaboration.

The second step in the District’s RACM process was to look 

at the EPA’s list of suggested control measures for PM2.5

nonattainment areas described in the 2007 PM2.5 Implementation 

Rule. The District summarized the results of this analysis in 

Table VI-3 in Appendix VI of the 2012 PM2.5 Plan. This analysis 

shows that the District either has a pre-existing rule or has 

developed a control measure for the 2012 PM2.5 Plan to address 

each of EPA’s suggested types of measures.

The third step in the District’s RACM process involved 

analyzing the District’s rules for compliance with the RACT 
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standard. The results of this analysis are summarized in Table 

VI-4, Appendix VI (page VI-10) of the 2012 PM2.5 Plan. The 

District further supplemented these analyses in the 2015 

Supplement, Attachment D, Tables D-4 to D-8 to address RACM and 

RACT requirements for direct PM2.5 and all PM2.5 precursors, and 

to provide reasoned justifications for control measures that 

were not adopted. A few examples of RACT-level rules in the 

South Coast include Rules 1146 and 1146.1, which control NOx 

from industrial and institutional boilers, Rule 1113.3, 

greenwaste composting, which in addition to providing a RACT 

level of control, also controls fugitives, Rule 1171, Solvent 

Cleaning, and Rule 1130, Graphic Arts.30

As part of these evaluations, the District compared its SIP 

rules with current rules, regulations and control measures 

implemented in other nonattainment areas. Specifically, the 

District re-evaluated all of its source category-specific rules 

and compared the requirements in these rules to more than 100 

 

30 The technical support documents for EPA’s rulemaking actions on these rules 

are available at: 

http://yosemite.epa.gov/r9/r9sips.nsf/AgencyProvision/5F5287B726E9E6F488257D7

90004839A/$file/1146+and+1146+1+June+2014.pdf?OpenElement, 

http://yosemite.epa.gov/r9/r9sips.nsf/AgencyProvision/5AD85F69581DEB9388257AC

50057D806?OpenDocument, 

http://yosemite.epa.gov/r9/r9sips.nsf/AgencyProvision/F65EA6DB0E3F7F068825792

10082BE8C?OpenDocument, and 

http://yosemite.epa.gov/r9/r9sips.nsf/AgencyProvision/865FFD6DBAC8018F88257E8

2007BA257/$file/1130+Jun+2015.pdf?OpenElement.
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rules from four other air districts in California (San Joaquin 

Valley, Sacramento Metropolitan, Ventura, and San Francisco Bay 

Area), the Dallas-Fort Worth and Houston-Galveston areas in 

Texas, New York, and New Jersey. A summary of this analysis is 

presented in the 2012 PM2.5 Plan, Appendix VI, Table VI-5 and in 

the 2015 Supplement, Attachment D. Table VI-5 identifies those 

rules from other areas that, based on the District’s review, may 

be more stringent in some respects than South Coast rules. With 

respect to South Coast Rules 1115, 1130, and 1168, the Plan 

states the District’s intention to provide further analyses at a 

later time. See 2012 PM2.5 Plan, Appendix VI, p. VI-9. Attachment 

D to the 2015 Supplement includes an updated RACM/RACT analysis 

with additional information on RACM for ammonia sources. The 

2015 Supplement also states that the District will further 

evaluate Rule 1115 and Rule 1168, and notes that Rule 1130 was 

recently amended to address the applicable CTG. See 2015 

Supplement, Attachment D, Table D-1 on p. D-5. 

According to the District, several of the requirements in 

South Coast Rule 1115, Motor Vehicle Assembly Line Coating 

Operations, are not as stringent as the recommendations in the 

2008 EPA CTG for a few coating processes emitting > 15 lbs/day. 

The two facilities subject to Rule 1115, however, have very 
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small emissions, a total of about 0.02 tpd of VOC.31 See 2015 

Supplement, Attachment D, page D-29. In December 2009, we 

approved Rule 1168, Adhesive and Sealant Applications, as 

satisfying VOC RACT requirements under CAA section 182(b)(2) 

(see 74 FR 67821, December 21, 2009). In 2014, the District 

amended South Coast Rule 1130, Graphic Arts, to reduce fountain 

solution VOC content to 16-85 g/L with optional control device 

efficiency of 90-95%, consistent with the EPA’s current CTG 

recommendations. On July 14, 2015, the EPA approved the revised 

South Coast Rule 1130 as satisfying VOC RACT requirements under 

CAA section 182(b)(2). (See 80 FR 40915.)

The RACM analyses and demonstrations conducted by CARB and 

SCAG for transportation and mobile source control measures are 

included in Appendix IV-C and its Attachment as well as the 

Attachment to Appendix VI of the 2012 PM2.5 Plan. CARB has unique 

authority under the CAA to adopt standards for most categories 

of on- and off-road engines and vehicles, subject in most 

instances to a waiver or authorization by EPA under CAA section 

209. The State of California has been a leader in the 

development of some of the most stringent control measures 

nationwide for on-road and off-road mobile sources and the fuels 

 

31 We note that 0.02 tpd is about 0.0044 percent of the total VOC inventory of 

451 tpd for 2014. See section II.A of the TSD. See email correspondence from 

Joseph Cassmassi, SCAQMD, to Stanley Tong, US EPA Region 9, dated November 

25, 2014 in the docket for today’s action.
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that power them. As part of its 2007 State Strategy as revised 

in 2009 and 2011 to support attainment plans in California for 

PM2.5 and 8-hour ozone, CARB undertook an extensive public 

consultation process to identify potential SIP measures. New 

measures adopted by CARB focused on cleaning up the in-use 

fleet, and increasing the stringency of emissions standards for 

a number of engine categories, fuels, and consumer products. 

CARB continues to expand its mobile source program to further 

reduce emission of direct PM2.5 and PM2.5 precursors. For example, 

in January 2012, CARB adopted the Advanced Clean Car program.32

SCAG focused its analysis on transportation control 

measures (TCMs) in the 2012-2035 Regional Transportation 

Plan/Sustainable Communities Strategy (RTP/SCS), and the 

analysis and results are described in Appendix IV-C of the 2012 

PM2.5 Plan, “Regional Transportation Strategy and Control 

Measures.” This evaluation considered transportation-related 

measures identified in section 108(f) of the CAA and measures 

adopted in other nonattainment areas of the country. SCAG 

provided a justification for measures that were determined to be 

infeasible for implementation in the South Coast nonattainment 

area. See 2012 PM2.5 Plan, Appendix IV-C.

 

32 See 78 FR 2112 (January 9, 2013).
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The inventory for ammonia, provided in Appendix V of the 

2012 PM2.5 Plan, indicates that the largest sources of ammonia 

include fuel combustion, waste disposal, miscellaneous sources, 

industrial sources, livestock, composting, domestic pets, and 

on-road mobile emissions. See Table 2 below (referencing 2012 

PM2.5 Plan at Appendix V, page V-4-2). The 2012 PM2.5 Plan and 2015 

Supplement identify five measures that control ammonia emissions 

sources in the South Coast. The five rules are Rule 223, 

Emissions Reduction Permits from Large Confined Animal Feeding 

Operations (adopted June 2, 2006); Rule 1105.1, Reductions of 

PM-10 and Ammonia Emissions from Fluid Catalytic Cracking Units 

(adopted November 7, 2003); Rule 1127, Emissions Reductions from 

Livestock Waste (adopted August 6, 2004); Rule 1133.2, Emission

Reductions from Co-Composting Operations (adopted January 10,

2003); and Rule 1133.3, Emission Reductions from Greenwaste

Composting Operations (adopted July 8, 2011).

Table 2. South Coast Ammonia Emissions Inventory for 2008 (tpd)

Source Category Ammonia 

Emissions

Livestock 18.6

Soil 1.8

Domestic 25.1

Landfill 3.6

Composting 17.8
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Fertilizer 1.5

Sewage Treatment 0.2

Wood Combustion 0.1

Industrial 20.2

On-Road Mobile 19.9

Off-road Mobile 0.1

TOTAL 108.9

Source: 2012 PM2.5 Plan, Appendix V, Table V-4-2.

 Rule 223, Emissions Reduction Permits from Large 

Confined Animal Feeding Operations (LCAF), is a work practice 

rule to control VOC and ammonia emissions from LCAFs. It 

requires operators and/or owners to implement management 

practices (e.g., feed according to National Research Council 

of the National Academy of Sciences guidelines, clean manure 

from corrals at least four times per year, land incorporate 

manure within 72-hours of removal, and allow liquid manure to 

stand in field no more than 24 hours after irrigation) for 

different components of the CAF operation, such as feeding, 

milking parlors, housing/bedding, manure management and land 

application. 

The EPA approved Rule 223 into the SIP on July 13, 2015 

(see 80 FR 39966). 

 Rule 1105.1, Reductions of PM10 and Ammonia Emissions 

from Fluid Catalytic Cracking Units (FCCU), is designed to 

limit PM10 and ammonia emissions from fluid catalytic cracking 
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units at oil refineries. The rule sets emission limits for PM10

and ammonia slip that result from the combination of FCCU 

emissions and ammonia injection used with electrostatic 

precipitators (ESP) to control FCCU emissions. Once in the 

atmosphere, ammonia emissions react with other compounds to 

produce secondary PM. The rule requires oil refineries to 

implement control technologies to meet the emissions limits 

including but not limited to dry and wet ESPs, sulfur oxide 

reducing agents, selective catalytic reduction, selective noncatalytic reduction, and wet gas scrubbers. The EPA approved 

this rule into the SIP on January 4, 2006 (see 71 FR 241). 

 Rule 1127, Emissions Reductions from Livestock Waste, 

requires dairies (and other types of dairy-cattle operations) 

to implement specific best management practices for manure 

management and disposal, and sets requirements for approving a 

facility as a manure processing operation. Specific 

requirements for ammonia include cleaning manure from corrals 

at least four times a year, disposing of manure only at 

approved manure processing operations, and applying it on 

agricultural land approved for that purpose. The EPA approved 

this rule into the SIP on May 23, 2013 (see 78 FR 30768). 
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 Rule 1133.2, Emission Reductions from Co-Composting

Operations, requires all new or existing co-composting 

operations to compost in an enclosure that meets certain 

technical requirements (e.g., inward face velocity of air 

through each opening shall be at least 100 feet per minute 

unless the opening contains closure seals), cure using an 

aeration system operating under negative pressure for no less 

than 90 percent of blower operating cycle, and vent the 

exhaust to an emission control system with a control 

efficiency for both VOC and ammonia of at least 80 percent, by 

weight, or submit a compliance plan for new operations that 

demonstrates an overall emission reduction for both VOC and

ammonia of 80 percent, by weight, based on emission factors 

specified in the rule. For existing operations, the required 

emission reduction is 70 percent, by weight, for both ammonia 

and VOC. Rule 1133.2 also specifies required compliance plan 

elements. The EPA approved this rule into the SIP on July 21, 

2004 (see 69 FR 43518).

 Rule 1133.3, Emission Reductions from Greenwaste

Composting Operations, requires all new or existing greenwaste 

(includes foodwaste) composting facilities to cover, water and 

turn active phase compost piles according to specific 

requirements (e.g., cover for seven days, turn only when top 
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of pile is sufficiently wet, based on test method) to minimize 

VOC and ammonia emissions. If total foodwaste throughput 

exceeds 5,000 tons per year, any active pile with more than 10 

percent foodwaste must be controlled by a device with an 

overall system control efficiency of 80 percent, by weight, 

each for VOC and ammonia emissions. The EPA approved this rule 

into the SIP on November 29, 2012 (see 77 FR 71129).

In addition, for livestock waste, the 2012 PM2.5 Plan and 

2015 Supplement indicate the District will evaluate control 

measure BCM-04, Further Ammonia Reductions from Livestock Waste, 

as a potential ammonia control measure. Phase I of this control 

measure, scheduled for the 2015-2016 timeframe, involves a 

technology assessment. The technology assessment will evaluate 

the technical and economic feasibility of applying sodium 

bisulfate (SBS) at local dairies in the South Coast. SBS 

application has been shown to be an effective method for 

reducing ammonia from fresh manure. (See 2012 PM2.5 Plan, 

Appendix IV, page IV-A-32). The 2015 Supplement states that rule 

development will follow if controls are determined to be 

technically feasible and cost-effective. See 2015 Supplement, 

page F-1 and Table F-1. 

We are proposing to reclassify the South Coast from 

Moderate to Serious nonattainment for the 2006 PM2.5 standard. A 
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final reclassification to Serious will trigger the requirement 

in CAA section 189(b)(1)(B) for the submittal of a SIP providing 

for the implementation of Best Available Control Measures 

(BACM),33 among other things, within 18 months. As part of the 

District’s development of a BACM control strategy for direct 

PM2.5 and those precursors subject to evaluation for potential 

controls in the South Coast (NOx, SO2, VOC, and ammonia), we 

encourage the District to consider additional measures 

previously identified by the EPA and the public in comments on 

the 2012 PM2.5 Plan, 2015 Supplement, and other individual rules 

and plans, as well as other potential innovative measures for 

reducing emissions. As part of this process, we suggest that the 

District consult with other state/local agencies and 

environmental and industry stakeholders. 

Condensable Fraction of Direct PM2.5 Emissions

EPA’s 2007 PM2.5 implementation rule states that “[a]fter 

January 1, 2011, for purposes of establishing emissions limits 

under 51.1009 and 51.1010, States must establish such limits 

 

33 The EPA defines BACM as, among other things, the maximum degree of 

emissions reduction achievable for a source or source category, which is 

determined on a case-by-case basis considering energy, environmental, and 

economic impacts. See Addendum at 42010, 42014. BACM must be implemented for 

all categories of sources in a serious PM2.5 nonattainment area unless the 

State adequately demonstrates that a particular source category does not 

contribute significantly to nonattainment of the PM2.5 standard. See id. At 

42011, 42012.
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taking into consideration the condensable fraction of direct 

PM2.5 emissions.” 40 CFR 51.1002(c). The South Coast 2012 PM2.5

Plan and 2015 Supplement rely on several SIP-approved rules 

regulating direct PM emissions as part of the PM2.5 control 

strategy (e.g., Wood Burning Fireplaces (Rule 445, adopted March 

7, 2008, most recently revised May 3, 2013), Wood Stoves and 

Under-Fired Charbroilers (Rule 1138, adopted November 14, 1997), 

and Particulate Matter (PM) Control Devices (Rule 1155, adopted 

December 4, 2009)). See 2015 Supplement, Attachment F, Table F-1 

and letter dated July 25, 2014 transmitting South Coast Rule 

1155 to EPA. As part of our action on any rules that regulate 

direct PM2.5 emissions, we evaluate the emission limits in the 

rule to ensure that they appropriately address CPM, as required 

by 40 CFR 51.1002(c). We note that the SIP-approved version of 

Rule 1138 requires testing according to the District’s Protocol, 

which requires measurement of both condensable and filterable PM 

in accordance with SCAQMD Test Method 5.1. See Rule 1138 

(adopted Nov. 14, 1997, approved July 11, 2011, see 66 FR 

36170), paragraph (c)(1) and (g) and SCAQMD Protocol paragraph 

3.1.34 We also note that the SIP-approved version of Rule 1155 

requires measurement of both condensable and filterable PM in 

 

34 See SCAQMD Protocol, Determination of Particulate and Volatile Organic 

Compound Emissions from Restaurant Operations, November 14, 1997 (available 

at 

http://yosemite.epa.gov/R9/R9Testmethod.nsf/0/3D4DEB4D21AB4AAF882570AD005DFF6

9/$file/SC%20Rest%20emiss.pdf).
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accordance with SCAQMD Test Methods 5.1, 5.2, or 5.3 as 

applicable. See Rule 1155 (adopted Dec. 4, 2009, approved March 

16, 2015, see 80 FR 13495), paragraph (e)(6).35 

3. Evaluation and Proposed Action

We find that the process followed in the 2012 PM2.5 Plan and 

2015 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 

control measures for sources of direct PM2.5, NOx, VOC, SO2, and 

ammonia in the South Coast. This list included measures 

suggested in public comments on the Plan. See 2012 PM2.5 Plan, 

Appendices VI and IV-C. As part of this process, the District, 

CARB, and SCAG 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 stated its intent to analyze potential rule 

improvements with respect to rules 1115, 1130, and 1168. See 

2012 PM2.5 Plan, Chapter 4 and Appendices VI, IV-A, and IV-C, and 

 

35 See SCAQMD Test Method 5.1, Determination of Particulate Matter Emissions 

from Stationary Sources Using a Wet Impingement Train, March 1989; SCAQMD 

Test Method 5.2, Determination of Particulate Matter Emissions from 

Stationary Sources Using Heated Probe and Filter, March 1989; and SCAQMD Test 

Method 5.3, Determination of Particulate Matter Emissions from Stationary 

Sources Using an in-Stack Filter, October 2005.
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2015 Supplement, Attachment D. Since submittal of the 2012 PM2.5

Plan in February 2013, the District has strengthened, adopted 

and submitted Rule 1130, which EPA approved on July 14, 2015 

(see 80 FR 40915). EPA approved Rule 1168 as satisfying VOC RACT 

on December 21, 2009 (see 74 FR 67821). With respect to Rule 

1115, as noted above, the emissions inventory for these sources 

is very small. 

We have reviewed the District’s determination in the 2012 

PM2.5 Plan and 2015 Supplement that its stationary and area 

source control measures represent RACM/RACT for direct PM2.5, NOx, 

VOC, ammonia and SO2. Our rulemaking actions on District rules 

generally provide the bases for our conclusions that the 

emission limits and/or other control requirements in the rules 

represent a RACT level of control, at minimum, for the relevant 

source categories.36 We also reviewed the potential additional 

control measures that the District considered, including those 

identified by public commenters during the State/District 

rulemaking processes, and believe that the District adequately 

justified its conclusions with respect to each of these 

measures.

 

36 A full list of the District’s rules, including citations to our most recent 

action on each rule can be found in Appendix A to this TSD. 
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Finally, we have reviewed the analysis of current and 

potentially available controls for both on-road and off-road 

mobile sources in Appendices IV-C and VI, as well as the 

Attachment to Appendix VI. As we have noted in previous actions 

on South Coast plans,37 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 South Coast through regulatory 

programs for both new and in-use vehicles and through incentive 

grant programs. See 2012 PM2.5 Plan, Appendix III, Table III-1-3. 

The District has also adopted measures to reduce emissions from 

mobile sources including its Surplus Opt-in for NOx (SOON) rule 

(Rule 2449) and on-road mobile sources including its employer 

trip reduction rule (Rule 2202) and has a well-funded incentive 

grants program focused on mobile sources. See 2012 PM2.5 Plan, 

Chapter 4. Overall, we believe that the State, District, and MPO 

programs provide for the implementation of RACM for emissions of 

direct PM2.5 and PM2.5 precursors from mobile sources in the South 

Coast.

For the foregoing reasons, we propose to find that the 2012 

PM2.5 Plan and 2015 Supplement provide for the implementation of 

 

37 See the proposed approvals of the South Coast 2007 [8-hour] Ozone Plan at 

76 FR 57872, 57879 (September 16, 2011) and the 2007 AQMP addressing the 1997 

PM2.5 NAAQS at 76 FR 41562. 41570 (July 14, 2011).
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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 South Coast 2012 PM2.5 Plan and 2015 

Supplement.38

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 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 (see General Preamble at 13539 and 13541 to 

42). The control requirements applicable to major stationary 

sources of direct PM2.5 and PM2.5 precursors in a Moderate PM2.5

nonattainment area include, at minimum, the requirements of a 

nonattainment new source review (NNSR) permit program meeting 

 

38 The 2012 PM2.5 Plan is the latest in a series of air quality plans and 

control strategies that the District, CARB and SCAG have developed to provide 

for attainment of the NAAQS in the South Coast. These plans include the 2003 

PM10 Plan (approved 70 FR 69081 (November 14, 2005)); the 2003 Extreme [1-

hour] Ozone Attainment Plan (approved 74 FR 10176 (March 8, 2009); the 2007 

[8-hour] Ozone Plan (approved 77 FR 12674 (March 1, 2012)); the 2007 State 

Strategy for the 1997 Ozone and PM2.5 standards (approved 76 FR 69928 (November 

9, 2011)); the 2007 PM2.5 SIP as revised in 2009 and 2011 (approved 66 FR 69928 

(November 9, 2011)); and the RACT SIP submitted in 2007 (approved 73 FR 76947 

(December 18, 2008)). In each of our rulemakings on these Plans, we approved 

a RACM and/or RACT demonstration that addressed one or more PM2.5 precursors. 
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the requirements of CAA section 172(c)(5) (see CAA 

189(a)(1)(A)). 

In a separate rulemaking to approve revisions to SCAQMD’s 

NNSR permit program, the EPA evaluated the District’s discussion 

of control requirements applicable to major stationary sources 

(Attachment E of the 2015 Supplement) and determined that the 

District’s SIP-approved NNSR program satisfies the requirements 

of CAA section 189(e) for direct PM2.5 and all PM2.5 precursors.39 

Accordingly, in this action, the EPA is not addressing the NNSR 

control requirements that apply to major stationary sources of 

direct PM2.5 and PM2.5 precursors in the South Coast area under 

CAA section 189(e). 

F. Adopted Control Strategy

1. Requirements for Control Strategies 

CAA section 110(a)(2)(A) provides that each SIP ‘‘shall 

include enforceable emission limitations and other control 

measures, means or techniques... as well as schedules and 

timetables for compliance, as may be necessary or appropriate to 

meet the applicable requirement of the Act.’’ Section 172(c)(6) 

of the Act, which applies to nonattainment area SIPs, is 

virtually identical to section 110(a)(2)(A).40 Measures necessary 

 

39 See n. 29, supra.

40 The language in sections 110(a)(2)(A) and 172(c)(6) is quite broad, 
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to meet RACM/RACT and the additional control requirements under 

section 172(c)(6) must be adopted by the State in an enforceable 

form (General Preamble at 13541) and submitted to the EPA for 

approval into the SIP under CAA section 110.

Commitments approved by the EPA under CAA section 110(k)(3) 

are enforceable by the EPA and citizens under CAA sections 113 

and 304, respectively. In the past, the EPA has approved 

enforceable commitments and courts have enforced actions against 

states that failed to comply with them.41 Additionally, if a 

state fails to meet its commitments, the EPA may make a finding 

of failure to implement the SIP under CAA section 179(a)(4), 

which starts an 18-month period for the state to correct the 

non-implementation before mandatory sanctions are imposed.

Once the EPA determines that circumstances warrant use of 

an enforceable commitment, the EPA considers three factors in 

determining whether to approve the use of an enforceable 

commitment to meet a CAA requirement: (a) does the commitment 

 

allowing a SIP to contain any enforceable “means or techniques” that EPA 

determines are “necessary or appropriate” to meet CAA requirements, such that 

the area will attain as expeditiously as practicable, but no later than the 

designated date. Furthermore, the express allowance for “schedules and 

timetables” demonstrates that Congress understood that all required controls 

might not be in place when a SIP is approved.

41 E.g., American Lung Ass'n of N.J. v. Kean, 670 F. Supp. 1285 (D.N.J. 1987), 

aff'd, 871 F.2d 319 (3rd Cir. 1989); NRDC, Inc. v. N.Y. State Dept. of Env. 

Cons., 668 F. Supp. 848 (S.D.N.Y. 1987); Citizens for a Better Env't v. 

Deukmejian, 731 F. Supp. 1448, recon. granted in par, 746 F. Supp. 976 (N.D. 

Cal. 1990); Coalition for Clean Air v. South Coast Air Quality Mgt. Dist., 

No. CV 97-6916-HLH, (C.D. Cal. Aug. 27, 1999).
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address a limited portion of the CAA-required program; (b) is 

the state capable of fulfilling its commitment; and (c) is the 

commitment for a reasonable and appropriate period of time.42

2. Control Strategy in the 2012 PM2.5 Plan and 2015 Supplement

For purposes of evaluating the 2012 PM2.5 Plan and 2015 

Supplement, we have divided the measures relied on to satisfy 

the applicable control requirements into two categories: 

baseline measures and control strategy measures.

As the term is used here, baseline measures are federal, 

State, and District rules and regulations adopted prior to June 

of 2012 for District rules, and prior to August of 2011 for CARB 

rules (i.e., prior to the development of 2012 PM2.5 Plan) that 

continue to achieve emissions reductions through the current 

attainment year of 2015 and beyond.43 The Plan describes many of 

these measures in Chapter 4 and in Appendices III, IV-B, IV-C 

and VI. Reductions from these baseline measures are incorporated 

into the baseline inventory and reductions from the District 

measures in the plan are individually quantified in Appendix 

 

42 The U.S. Court of Appeals for the Fifth Circuit upheld the EPA's 

interpretation of CAA section 110(a)(2)(A) and 172(c)(6) and the Agency's use 

and application of the three factor test in approving enforceable commitments 

in the Houston-Galveston ozone SIP in BCCA Appeal Group et al. v. EPA et al., 

355 F.3d 817 (5th Cir. 2003).

43 These measures are typically rules that have compliance dates that occur 

after the adoption date of a plan and mobile source measures that achieve 

reductions as older engines are replaced through attrition (e.g., through 

fleet turnover).
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III, Table III-2-2B. According to the Plan, these measures 

provide most of the emissions reductions projected to occur 

between the base year of 2008 and the Moderate area attainment 

date of 2015. See 2012 PM2.5 Plan, Chapter 4, and Appendix V, and 

2015 Supplement Attachment A; see also Appendix A of the TSD.

Control strategy measures are the new rules, rule 

revisions, commitments, and other measures that provide the 

additional increment of emissions reductions needed beyond the 

baseline measures to provide for attainment (when applicable), 

to demonstrate RFP, to meet the RACM/RACT requirement, or to 

provide for contingency measures.

The District included several new measures in the 2012 PM2.5

Plan and 2015 Supplement to provide for attainment of the 2006 

PM2.5 NAAQS. First, the District committed to adopt, submit, and 

implement amendments to two District rules (Rule 444 and Rule 

445) to reduce direct PM2.5 emissions from open burning and 

residential wood burning activities. See 2012 PM2.5 Plan, p. 4-8, 

Table 4-2 and SCAQMD Governing Board Resolution 12-19 (Dec. 7, 

2012), p. 8, as revised by 2015 Supplement, Attachment F, Table 

F-1 and SCAQMD Governing Board Resolution 15-2 (Feb. 19, 2015). 

Second, the District committed to achieve 11.7 tpd of direct 

PM2.5 emission reductions by 2015, either from these two amended 

rules or from substitute measures as necessary to address any 
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shortfall in emission reductions. Id. Third, the District 

committed to carry out technology assessments to address 

emissions from under-fired charbroilers and livestock waste in 

2015-2016 and 2017, respectively. Id. Finally, the District 

committed to adopt revisions to its NOx RECLAIM program to 

achieve an additional 2 tpd of NOx emission reductions in 2015, 

as a contingency measure, and to adopt backstop measures related 

to ports and port-related facilities in 2015. Id. Following the 

State’s submittal of the 2012 PM2.5 Plan to the EPA in 2013, the 

District adopted amendments to Rule 444 and Rule 445 and on June 

11, 2013, the District submitted these revised rules to the EPA 

for SIP approval, consistent with its commitments in the Plan. 

These measures and commitments are listed in Table 3 below. 
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Table 3. SCAQMD 2012 PM2.5 Plan and 2015 Supplement Specific Commitments

Rul

e 

Num

ber 

Measure Number & Description Adoption 

Date

Implement

ation 

Date

Emission 

Reductions

444 Further Reductions from Open 

Burning44

2013

2013

4.6 tpd 

PM2.5

445 Further Reductions from 

Residential Wood Burning45

2013

2013

7.1 tpd 

PM2.5

113

8

Emissions Reductions from 

Under-fired Charbroilers

2017 N/A TBD

112

7

Further Ammonia Emissions From 

Livestock Waste

2015-2016

Technology 

Assessment

N/A TBD

200

2

Further NOx Reductions from 

RECLAIM 2015 N/A 2 tpd NOx

400

1

Backstop Measures for Indirect 

Sources of Emissions from 

Ports and Port-related 

Facilities

2015 N/A N/A

Source: 2012 PM2.5 Plan, Chapter 4, Table 4-2, as amended by 2015 Supplement, 

Attachment F, Table F-1.

3. Evaluation and Conclusions

The Plan provides for the majority of the emissions 

reductions necessary for attainment to be achieved from baseline 

measures. These reductions come from a combination of District, 

State and federal stationary and mobile source measures.46 Over 

the past four decades, the District has adopted or revised 

 

44 Approved on September 26, 2013, see 78 FR 59249.

45 Ibid.

46 These federal measures include EPA’s national emissions standards for heavy 

duty diesel trucks (66 FR 5001 (January 18, 2001)), certain new construction 

and farm equipment (Tier 2 and 3 non-road engines standards, 63 FR 56968 

(October 23, 1998) and Tier 4 diesel non-road engine standards, 69 FR 38958 

(June 29, 2004)), and locomotives (63 FR 18978 (April 16, 1998) and 

73 FR 37045 (June 30, 2008)). States are allowed to rely on reductions from 

federal measures in attainment and RFP demonstrations and for other SIP 

purposes.
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almost 100 prohibitory rules that limit emissions of NOx, SO2, 

ammonia, VOC, and particulate matter from stationary sources. 

See Appendix A of this TSD. The vast majority of these rules are 

currently SIP-approved and as such, their emissions reductions 

are fully creditable in attainment-related SIPs. The District’s 

most recent amendments to Rule 444 and Rule 445 further tighten 

the District’s control strategy for direct PM2.5 emissions. 

California has also adopted standards for many categories of onand off-road vehicles and engines as well as standards for 

gasoline and diesel fuels. 

The State’s mobile source measures fall into two 

categories: measures for which the State has obtained or has 

applied to obtain a waiver of federal pre-emption under 

CAA section 209 (“section 209 waiver measures” or “waiver 

measures”) and those for which the State is not required to 

obtain a waiver (“non-waiver measures” or “SIP measures”).

Under the CAA, the EPA is charged with establishing 

national emission limits for mobile sources. States are 

generally preempted from establishing such limits except for 

California, which can establish these limits subject to EPA 

waiver or authorization under CAA section 209 (referred to 

herein as “waiver measures”). Over the years, the EPA has issued 

waivers or authorizations for many mobile source regulations 
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adopted by CARB. California attainment and maintenance plans 

rely on emissions reductions from implementation of the waiver 

measures through use of emissions models such as EMFAC, and the 

South Coast 2012 PM2.5 Plan is no exception.

Historically, the EPA has allowed California to take credit 

for such “waiver” measures even though the waiver measures 

themselves (i.e., CARB’s regulations) have not been adopted and 

approved as part of the California SIP. However, a recent 

decision by the Ninth Circuit Court of Appeals held that EPA’s 

longstanding practice in this regard was at odds with the CAA 

requirement that state and local emissions limits relied upon to 

meet the NAAQS be enforceable by the EPA or private citizens 

through adoption and approval of such limits in the SIP.47

In response to the court’s decision, CARB has adopted the 

necessary waiver measures as revisions to the California SIP and 

submitted them to EPA for approval.48 EPA intends to propose 

action on these waiver measures in a separate rulemaking. Once 

approved as part of the SIP, the measures will be enforceable by 

the EPA or private citizens under the CAA. In today’s action, 

the EPA is proposing to approve certain elements of the 2012 

PM2.5 Plan and 2015 Supplement in part based on our expectation 

 

47 See Committee for a Better Arvin v. EPA, 786 F.3d 1169 (9th Cir. 2015). 

48 See letter dated August 14, 2015, from Richard W. Corey, Executive Officer, 

California Air Resources Board, to Jared Blumenfeld, Regional Administrator, 

EPA Region 9.
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that these waiver measures will soon become federally

enforceable as a result of our approval of the measures as part 

of the SIP.

Non-waiver measures include improvements to California’s 

inspection and maintenance (I/M) program, SmogCheck, and cleaner 

burning gasoline and diesel regulations as well as the 

District’s stationary source and mobile source rules. See TSD at 

Appendix A for a list of District rules and EPA actions on them.

As discussed above, we generally consider three factors in 

determining whether to approve the use of enforceable 

commitments to meet a CAA requirement. In this case, however, 

the 2012 PM2.5 Plan and 2015 Supplement do not rely on either the 

rule amendment commitments or the emission reduction commitments 

in its impracticability demonstration, RACM demonstration, RFP 

demonstration, or quantitative milestones, or to meet any other 

CAA requirement. Therefore, we do not need to apply this threefactor test before proposing to approve the District’s 

commitments into the SIP. Approval of these commitments will 

strengthen the SIP and contribute to the SIP’s purpose of 

“eliminating or reducing the severity and number of violations 

of the [PM2.5 NAAQS] and achieving expeditious attainment of such 

standards.” See CAA 176(c)(1)(A). 
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We are proposing to approve the District’s commitments to 

adopt and implement specific control measures identified in 

Table 4-2 in the South Coast 2012 AQMP (as amended March 4, 2015 

by Table F-1 in Attachment F of the 2015 Supplement) and to 

achieve specified NOx emission reductions, to the extent that 

these commitments have not yet been fulfilled. Specifically, we 

are proposing to approve the District’s commitments to: (1)

carry out a technology assessment to address emissions from 

under-fired charbroilers by 2017, (2) conduct a technology 

assessment for livestock waste by 2016, (3) adopt revisions to 

its NOx RECLAIM program or other enforceable control measures to 

achieve an additional 2 tpd of NOx emission reductions in 2015, 

and (4) adopt backstop measures for indirect sources of 

emissions from ports and port-related facilities. See 2012 PM2.5

Plan, p. 4-8, Table 4-2 and SCAQMD Governing Board Resolution 

12-19 (Dec. 7, 2012), pp. 7-8, as revised by 2015 Supplement, 

Attachment F, Table F-1 and SCAQMD Governing Board Resolution 

15-2 (Feb. 19, 2015), pp. 2-3.

With respect to the commitments to adopt Rules 444 and 445 

and to achieve 11.7 tpd of direct PM2.5 emission reductions, the 

District has satisfied these commitments by submitting the fully 

adopted rules to EPA on June 11, 2013, together with technical 

documentation to support its conclusion that these rules will 
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achieve 11.7 tpd of direct PM2.5 emission reductions in 2015.49

The EPA approved Rule 444 and Rule 445 on September 26, 2013 

(see 79 FR 59249).50

G. Demonstration that Attainment by the Moderate Area Attainment 

Date is Impracticable

1. Requirements for Attainment/Impracticability of Attainment 

Demonstrations

CAA section 189(a)(1)(B) requires that each Moderate area 

attainment plan include a demonstration that the plan provides 

for attainment by the latest applicable Moderate area deadline

or, alternatively, that attainment by the latest applicable

attainment date is impracticable. A demonstration that the plan 

provides for attainment must be based on air quality modeling, 

and the EPA generally recommends that a demonstration of 

impracticability also be based on air quality modeling 

consistent with EPA’s modeling guidance (General Preamble at 

13538).51

 

49 See “Rule Evaluation Form,” South Coast Rules 444 and 445, and South Coast 

Air Quality Management District, Draft Final Staff Report, Proposed Amended 

Rule 445 – Wood-Burning Devices, Proposed Amended Rule 444 – Open Burning, 

May 2013, pp. 15-16.

50 See letter dated June 11, 2013, from Edie Chang, Deputy Executive Officer, 

California Air Resources Board, to Jared Blumenfeld, Regional Administrator, 

EPA Region 9, transmitting South Coast Rules 444 and 445.

51 For more information on the CAA’s air quality modeling requirements, please 

see section II.B of the TSD.
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CAA section 188(c) states, in relevant part, that the 

Moderate area attainment date “shall be as expeditiously as 

practicable but no later than the end of the sixth calendar year 

after the area’s designation as nonattainment....” For the South 

Coast area, which was initially designated as nonattainment for 

the 2006 PM2.5 standard effective December 14, 2009, the 

applicable Moderate area attainment date under section 188(c) is 

as expeditiously as practicable but no later than December 31, 

2015.

In SIP submissions to demonstrate impracticability, the 

State should document that its required control strategy in the 

attainment plan represents the application of RACM/RACT to 

existing sources. The EPA believes it is appropriate to require 

adoption of all available control measures that are reasonable 

(i.e., technologically and economically feasible) in areas that 

do not demonstrate timely attainment, even where those measures 

cannot be implemented within the 4-year timeframe for 

implementation of RACM under CAA section 189(a)(1)(C). The 

impracticability demonstration will then be based on a showing 

that the area cannot attain by the applicable attainment date, 

notwithstanding implementation of the required controls.
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2. Impracticability Demonstration for the 2012 PM2.5 Plan and 

2015 Supplement

By letter dated July 28, 2015, the District requested that 

the EPA reclassify the South Coast Air Basin to “Serious” for 

the 2006 PM2.5 NAAQS. The letter provided preliminary 2015 air 

quality monitoring data for the Mira Loma monitoring station 

supporting a conclusion that attainment of the 2006 PM2.5

standard by December 31, 2015 in the South Coast is 

impracticable.52

Based in part on the information contained in this letter 

and in the 2012 PM2.5 Plan and Supplement, we have conducted an 

analysis of recent PM2.5 monitoring data for the South Coast PM2.5

nonattainment area.53 For this analysis, the EPA used certified 

data for 2013, 2014 and preliminary data available for 2015.54

Although the State and District originally intended for the 2012 

PM2.5 Plan and 2015 Supplement to demonstrate that the area would 

attain the 2006 PM2.5 NAAQS by the Moderate area attainment date 

 

52 See letter dated July 28, 2015, from Barry R. Wallerstein, Executive 

Officer, SCAQMD, to Elizabeth Adams, Acting Director, Air Division, US 

Environmental Protection Agency, Region 9.

53 See Memorandum dated August 21, 2015 from Michael Flagg, U.S. EPA, Region 9 

Air Quality Analysis Office, to South Coast Docket EPA-R09-OAR-2015-0204, 

Subject: Practicability of South Coast 2015 Attainment of the 2006 24-hour PM 

NAAQS (“Flagg Memo”).

54 Some data in the 2nd, 3rd, and 4th quarter of 2014 may have been impacted by 

a temporary lab closure and other issues at SCAQMD and are under current 

review. As a precautionary measure, we conducted an additional analysis on 

the impracticability of attaining by December 31, 2015 that completely 

excluded these data. The outcome of the analysis further supported the 

impracticability of attainment by the applicable attainment date. See

Attachment to Flagg Memo, under “24-hour practicability” tab.
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of December 31, 2015, more recent monitoring data show that 24-

hour PM2.5 levels in the South Coast, with a current design value 

(2012-2014) of 38 μg/m3 at the Mira Loma monitoring site, 

continue to be above the 35 μg/m3 level of the 2006 PM2.5

standard, and the recent trends in the South Coast’s 24-hour 

PM2.5 levels are not consistent with a projection of attainment 

by the end of 2015.

The EPA calculated the maximum allowed 2015 concentrations 

for all monitors in the area, and compared them to the estimated 

2015 98th percentile. If the estimated 2015 98th percentile was 

greater than the maximum allowed 2015 98th percentile 

concentration, the EPA considered attainment at that monitoring 

site impracticable. For each monitor, the EPA estimated the 

2015 98th percentile from the 2015 data available in AQS as of 

August 2015, based a number of assumptions.55 The EPA assumed 

that the concentrations measured during the remainder of 2015 

would be no higher than those already recorded, so the 98th

percentile could be chosen from among the already recorded data. 

This is a conservative assumption for assessing the 

impracticability of attainment, since future concentrations and 

98th percentiles could be higher than recorded values. 

 

55 EPA also assumed that the sampling rate observed so far would continue 

throughout the year; this yielded an estimate of the number of total samples 

expected for 2015, and allowed for selection of the corresponding rank of the 

daily data available to use as the 98th percentile in accordance with 40 CFR 

part 50, appendix N, section 4.5. 
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The EPA’s analysis showed that during 2015, two monitoring

sites (Rubidoux and Mira Loma-Van Buren) had estimated 98th

percentiles greater than the maximum allowed 98th percentile 

concentration for 2015, which indicates that attainment of the 

2006 24-hour PM2.5 NAAQS by the end of 2015 is impracticable.

In a separate analysis, EPA assumed that Rubidoux and Mira 

Loma-Van Buren collected a minimum of 351 daily samples (i.e.

consistent with an everyday sampling frequency) in 2015, which 

would allow for selection of the 8th highest recorded value as 

the 98th percentile for 2015. This assumption resulted in 

selection of the lowest 98th percentile value possible for 2015, 

making the analysis more conservative than the previous 

approach. Even under this assumption, both Rubidoux and Mira 

Loma-Van Buren had estimated 2015 98th percentiles greater than 

the maximum allowed 2015 98th percentile.

3. Evaluation and Proposed Action

Our conservative assessment of recent PM2.5 air quality data 

indicates that attainment of the 2006 PM2.5 standard in the South 

Coast by December 31, 2015 is impracticable. We have also 

evaluated the RACM/RACT demonstration in the 2012 PM2.5 Plan and 

2015 Supplement and find that it provides for the expeditious 

implementation of all RACM that may feasibly be implemented at 
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this time, consistent with the requirements of CAA sections 

172(c)(1) and 189(a)(1)(C) for the 2006 PM2.5 NAAQS in the South 

Coast. See section II.D of this TSD. Implementation of this 

RACM/RACT control strategy appears, however, to be insufficient 

to bring the South Coast area into attainment by December 31, 

2015.

Based on this evaluation, we propose to approve the State’s 

demonstration in the 2012 PM2.5 Plan and 2015 Supplement that 

attainment of the 2006 PM2.5 standard by the Moderate area

attainment date in the South Coast is impracticable, consistent 

with the requirements of CAA section 189(a)(1)(B)(ii). Based on 

this proposal, we propose to reclassify the South Coast as 

Serious nonattainment, which would trigger requirements for the 

State to submit a Serious area plan consistent with the 

requirements of subparts 1 and 4 of part D, Title I of the Act 

(see Section III of this TSD).

H. Reasonable Further Progress and Quantitative Milestones

1. Requirements for Reasonable Further Progress and Quantitative 

Milestones

CAA section 172(c)(2) requires nonattainment area plans to 

provide for reasonable further progress (RFP). In addition, CAA 
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section 189(c) requires PM2.5 nonattainment area SIPs to include 

quantitative milestones to be achieved every 3 years until the 

area is redesignated to attainment and which demonstrate 

reasonable further progress (RFP), as defined in CAA section 

171(1). Section 171(1) defines RFP as "such annual incremental 

reductions in emissions of the relevant air pollutant as are 

required by [Part D] or may reasonably be required by the 

Administrator for the purpose of ensuring attainment of the 

applicable [NAAQS] by the applicable date.’’ Neither subpart 1 

nor subpart 4 of part D, title I of the Act requires that a set 

percentage of emissions reductions be achieved in any given year 

for purposes of satisfying the RFP requirement.

RFP has historically been met by showing annual incremental 

emission reductions sufficient generally to maintain at least 

linear progress toward attainment by the applicable deadline 

(Addendum at 42015). As discussed in the Addendum, requiring 

linear progress in reductions of direct PM2.5 and any individual 

precursor in a PM2.5 plan may be appropriate in situations where: 

 the pollutant is emitted by a large number and 

range of sources,

 the relationship between any individual source or 

source category and overall air quality is not well known, 

 a chemical transformation is involved (e.g., 

secondary particulate significantly contributes to PM2.5

levels over the standard), and/or
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 the emission reductions necessary to attain the 

PM2.5 standard are inventory-wide. Id.

The EPA’s guidance in the Addendum at 42015 recommends that 

requiring linear progress is less appropriate in other 

situations, such as:

 where there are a limited number of sources of 

direct PM2.5 or a precursor,

 where the relationships between individual 

sources and air quality are relatively well defined, and/or

 where the emission control systems utilized 

(e.g., at major point sources) will result in swift and 

dramatic emission reductions. Id.

In nonattainment areas characterized by any of these latter 

conditions, RFP may be better represented as step-wise progress 

as controls are implemented and achieve significant reductions 

soon thereafter. For example, if an area’s nonattainment problem 

can be attributed to a few major sources, EPA guidance indicates 

that ‘‘RFP should be met by ‘adherence to an ambitious 

compliance schedule’ which is likely to periodically yield 

significant emission reductions of direct PM2.5 or a PM2.5

precursor’’ (Addendum at 42015).

Plans for PM2.5 nonattainment areas should include detailed 

schedules for compliance with emission regulations in the area 

and provide corresponding annual emission reductions to be 

realized from each milestone in the schedule (Addendum at 

42016). In reviewing an attainment plan under subpart 4, EPA 
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evaluates whether the annual incremental emission reductions to 

be achieved are reasonable in light of the statutory objective 

of timely attainment. 

Section 189(c) provides that the quantitative milestones 

submitted by a state for an area also must be consistent with 

RFP for the area. Thus, the EPA determines an area’s compliance 

with RFP in conjunction with determining its compliance with the 

quantitative milestone requirement. Because RFP is an annual 

emission reduction requirement and the quantitative milestones 

are to be achieved every 3 years, when a state demonstrates an 

area’s compliance with the quantitative milestone requirement, 

it will demonstrate that RFP has been achieved during each of 

the relevant 3 years. Quantitative milestones should consist of 

elements that allow progress to be quantified or measured. 

Specifically, states should identify and submit quantitative 

milestones providing for the amount of emission reductions 

adequate to achieve the NAAQS by the applicable attainment date 

(Addendum at 42016). Implementation of control measures 

comprising the RFP plan may provide a means for satisfying the 

quantitative milestone requirement (see id.). The Act requires 

states to include RFP and quantitative milestones even for areas 

that cannot practicably attain.
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2. RFP Demonstration and Quantitative Milestones in the 2012 

PM2.5 Plan and 2015 Supplement 

South Coast’s 2012 PM2.5 Plan was originally developed in 

accordance with the requirements of subpart 1 and the 2007 PM2.5

Implementation Rule (see 75 FR 20586, April 25, 2007), which did 

not require a submittal of a separate RFP plan where the State 

submits a plan demonstrating attainment within five years of the 

date of designation (see 40 CFR 51.1009(b)). Because the 2012

PM2.5 Plan as originally adopted (in December 2012) included the 

State’s demonstration of attainment by December 14, 2014, which 

is five years from the date of designation,56 the Plan does not 

include a separate RFP demonstration. 

Following the D.C. Circuit’s January 2013 decision 

remanding the 2007 PM2.5 Implementation Rule (see NRDC v. EPA, 

706 F.3d 428 (D.C. Cir. 2013)) and the EPA’s June 2014 

promulgation of Moderate area classifications in the deadline 

and classifications rule (see 79 FR 31566, June 2, 2014), the 

District developed the 2015 Supplement to address the applicable 

subpart 4 requirements for the 2006 PM2.5 NAAQS. By the time the 

 

56 Section 172(a)(2)(A) of the CAA states, in relevant part, that the 

attainment date for a nonattainment area “shall be the date by which 

attainment can be achieved as expeditiously as practicable, but no later than 

5 years from the date such area was designated nonattainment under section 

[107(d)].” Because the EPA designated South Coast as nonattainment for the 

2006 24-hour standard effective December 14, 2009 (74 FR 58688, November 13, 

2009), under subpart 1 the area was required to attain this standard no later 

than December 14, 2014.
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State and District submitted this Supplement to EPA in early 

2015, less than a year remained before the December 31, 2015 

Moderate area attainment date applicable to the area under 

subpart 4, and ambient air quality monitoring data indicated the 

area was very close to attaining the 2006 PM2.5 standard. See 

2015 Supplement, p. 4. Accordingly, the 2015 Supplement does 

not contain a separate RFP or quantitative milestone 

demonstration.

3. Evaluation and Proposed Action

As a result of the NRDC decision remanding the 2007 PM2.5

Implementation Rule, the EPA has considered whether the 2012 

PM2.5 Plan and 2015 Supplement meet the RFP requirement in 

section 172(c)(2) of the Act and proposes to find that they do.

The 2012 PM2.5 Plan demonstrates that all RACM/RACT are being 

implemented as expeditiously as practicable and identifies 

projected emission levels for 2014 that reflect full 

implementation of the State’s and District’s RACM/RACT control 

strategy for the area.57 The Plan also shows steady reductions 

in direct PM2.5, NOx, VOC, SOx, and ammonia emissions during the 

2008-2014 period. Figures IIH-1 and IIH-2 show the emissions 

 

57 See 2012 PM2.5 plan at Chapter 4, pp. 4-4 through 4-13, Table 4-7, and 

Appendix III, Table III-2-2B (“Emission Reductions (Tons per Day) in the 

Baseline by District Rules”). 
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trajectories for direct PM2.5 and each PM2.5 precursor addressed 

in the control strategy which indicate generally linear 

reductions. We propose, therefore, to approve the 2012 PM2.5 Plan 

and 2015 Supplement as satisfying the requirement for RFP in CAA 

section 172(c)(2) for the 2006 PM2.5 standard.

With respect to quantitative milestones, the EPA is 

proposing to establish December 31, 2014 as the starting point 

for the first 3-year period under CAA section 189(e) for the 

2006 PM2.5 standard in the South Coast. This date is the due date 

for the State’s submittal of attainment-related SIPs necessary 

to satisfy the Moderate area requirements applicable to the 

South Coast area.58 Accordingly, the first quantitative milestone 

date for the South Coast area would be December 31, 2017 (3 

years after December 31, 2014). Because this date falls well 

after the applicable Moderate area attainment date for the area, 

which is December 31, 2015, we propose to find that quantitative 

milestones are not necessary in this particular Moderate area 

plan. If, however, EPA either finalizes this proposal to 

reclassify the South Coast area as Serious nonattainment for the 

2006 PM2.5 standard or determines that the area has failed to 

 

58 Subpart 4 requires states to submit attainment plans within 18 months after 

nonattainment designations (CAA 189(a)(2)). Due to unusual circumstances, 

however, the EPA has by rule created a later deadline for submittal of 

attainment plan submission date for the 2006 PM2.5 NAAQS in order to provide 

states a reasonable amount of time to address the requirements of subpart 4 

consistent with the NRDC decision. See 79 FR 31566 (June 2, 2014).
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attain by the December 31, 2015 attainment date, the State and 

District will be required to submit a Serious area plan that 

contains, among other things, quantitative milestones that 

demonstrate RFP at each milestone date, starting December 31, 

2017 and at subsequent 3-year intervals until the area is 

redesignated to attainment.

I. Contingency Measures

1. Requirements for Contingency Measures

Under CAA section 172(c)(9), PM2.5 plans must include 

contingency measures to be implemented if an area fails to meet 

RFP ("RFP contingency measures") and, where the SIP includes a 

demonstration of attainment (as opposed to a demonstration of 

impracticability), contingency measures to be implemented if an 

area fails to attain the PM2.5 standards by the applicable 

attainment date (‘‘attainment contingency measures’’). Under 

subpart 4, however, the EPA interprets section 172(c)(9) in 

light of the specific requirements for particulate matter 

nonattainment areas. Section 189(b)(1)(A) differentiates between 

attainment plans that provide for timely attainment and those 

that demonstrate that attainment is impracticable. Where a SIP 

includes a demonstration that attainment by the applicable 

attainment date is impracticable, the state need only submit 
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contingency measures to be implemented if an area fails to meet 

RFP.59

The purpose of contingency measures is to continue progress 

in reducing emissions while the SIP is being revised to meet the 

missed RFP milestone or to provide for attainment.

The principal requirements for contingency measures are:

 Contingency measures must be fully adopted rules or control 

measures that are ready to be implemented quickly upon 

failure to meet RFP or failure of the area to meet the 

standard by its attainment date.

 The SIP should contain trigger mechanisms for the 

contingency measures, specify a schedule for 

implementation, and indicate that the measures will be 

implemented without further action by the state or by the 

EPA. In general, we expect all actions needed to effect 

full implementation of the measures to occur within 60 days 

after the EPA notifies the state of a failure.

 

59 The EPA does not interpret the requirement for failure-to-attain 

contingency measures to apply to Moderate PM2.5 nonattainment areas that cannot 

practicably attain the NAAQS by the statutory attainment date. Rather, the 

EPA believes it is appropriate for the state to identify and adopt attainment 

contingency measures as part of the Serious area attainment plan that it will 

develop once the EPA reclassifies the area (Addendum at 42015). 
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 The contingency measures should consist of control measures 

for the area that are not relied on to demonstrate 

attainment or RFP. 

 The measures should provide for emissions reductions 

equivalent to approximately one year of reductions needed 

for RFP calculated as the overall level of reductions 

needed to demonstrate attainment divided by the number of 

years from the base year to the attainment year.

(General Preamble at 13543 and Addendum at 42014).

2. Contingency Measures in the 2012 PM2.5 Plan and 2015 

Supplement

Contingency measures for failure to attain are described in 

Chapter 6, pages 6-7 to 6-13 of the 2012 PM2.5 Plan. The 2012 

PM2.5 Plan and 2015 Supplement do not include contingency 

measures for failure to meet RFP. 

3. Evaluation and Proposed Action

Because we are proposing to approve the State’s 

demonstration that attainment by the applicable Moderate area 

attainment date of December 31, 2015 is impracticable in the 

South Coast and to reclassify the area to serious, contingency 

measures for failure to attain are not required as part of this 

Moderate area plan. Upon reclassification of the South Coast 
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area as a Serious area, California will be required to adopt 

attainment contingency measures as part of the Serious area 

attainment plan for the 2006 PM2.5 NAAQS.

We propose to find that the RFP contingency measure 

requirement for any RFP milestone year prior to 2014 is now moot 

as applied to the South Coast PM2.5 nonattainment area. The sole 

purpose of RFP contingency measures is to provide continued 

progress if an area fails to meet its RFP goal. Failure to meet 

any milestone year target prior to 2014 would have required 

California to implement RFP contingency measures in the South 

Coast and to revise the 2012 PM2.5 Plan to assure that it still 

provided for attainment by the applicable attainment date of 

December 31, 2015. In this case, however, the 2012 PM2.5 Plan and 

2015 Supplement demonstrate that actual emission levels in the 

years leading up to 2014 were consistent with RFP for direct 

PM2.5 and all four precursor pollutants (NOx, SOx, VOC and 

ammonia) regulated in the 2012 PM2.5 Plan. Accordingly, RFP 

contingency measures no longer have meaning or purpose, and 

therefore EPA proposes to find that the requirement for them is 

now moot. 

J. Motor Vehicle Emission Budgets

1. Requirements for Motor Vehicle Emissions Budgets
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CAA section 176(c) requires Federal actions in 

nonattainment and maintenance areas to conform to the SIP’s 

goals of eliminating or reducing the severity and number of 

violations of the NAAQS and achieving expeditious attainment of 

the standards. Conformity to the SIP’s goals means that such 

actions will not: (1) cause or contribute to violations of a 

NAAQS, (2) worsen the severity of an existing violation, or (3) 

delay timely attainment of any NAAQS or any interim milestone.

Actions involving Federal Highway Administration (FHWA) or 

Federal Transit Administration (FTA) funding or approval are 

subject to the EPA’s transportation conformity rule, codified at 

40 CFR part 93, subpart A. Under this rule, MPOs in 

nonattainment and maintenance areas coordinate with state and 

local air quality and transportation agencies, the EPA, FHWA, 

and FTA to demonstrate that an area’s RTP and transportation 

improvement program (TIP) conform to the applicable SIP. This 

demonstration is typically done by showing that estimated 

emissions from existing and planned highway and transit systems 

are less than or equal to the motor vehicle emissions budgets 

(budgets) contained in all control strategy SIPs. An attainment, 

maintenance, or RFP SIP should include budgets for the 

attainment year, each required RFP year, or the last year of the 

maintenance plan, as appropriate. Budgets are generally 
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established for specific years and specific pollutants or 

precursors and must reflect all of the motor vehicle control 

measures contained in the attainment and RFP demonstrations 

(40 CFR 93.118(e)(4)(v)).

PM2.5 plans should identify motor vehicle emission budgets 

for direct PM2.5 and all significant PM2.5 precursors for each RFP 

milestone year and the attainment year, if the plan demonstrates 

attainment. All direct PM2.5 SIP budgets should include direct 

PM2.5 motor vehicle emissions from tailpipe, brake wear, and tire 

wear. A state must also consider whether re-entrained paved and 

unpaved road dust or highway and transit construction dust are 

significant contributors and should be included in the direct 

PM2.5 budget. See 40 CFR 93.102(b) and 93.122(f) and the 

conformity rule preamble at 69 FR 40004, 40031–40036 

(July 1, 2004). 

2. Motor Vehicle Emissions Budgets in the 2012 PM2.5 Plan and 

2015 Supplement

The 2015 Supplement revised the attainment demonstration in 

the 2012 PM2.5 Plan to identify December 31, 2015 as the 

applicable attainment date, and included revised budgets for 

2015 for directly emitted PM2.5, NOx, and VOC. See 2015 

Supplement, Attachment C, Table C-1. These budgets reflect 

average annual daily emissions and are calculated using 
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EMFAC2011, the currently approved mobile source emission model 

for California, and transportation activity from SCAG’s adopted 

2012 Regional Transportation Plan (RTP), consistent with the 

methodology for developing the emissions inventories used in the 

attainment demonstration. Reductions from incentive measures 

were removed from the budgets, and off-model reductions for 

reformulated gasoline (RFG) and SmogCheck (California’s 

inspection and maintenance program) which were not in EMFAC2011

were included in the budgets, consistent with the emissions 

inventory used in the attainment demonstration. 

The direct PM2.5 budgets included tailpipe, brake wear, and 

tire wear emissions as well as paved and unpaved road dust and 

road construction dust. No budgets for SO2 were included in the 

2012 PM2.5 Plan or 2015 Supplement because on-road emissions of 

SO2 are a small part (11 percent) of the total SO2 inventory. No 

budgets for ammonia were included in the 2012 PM2.5 Plan or 2015 

Supplement. 

3. Conclusion and Proposed Actions 

We are not acting on the motor vehicle emission budgets for 

direct PM2.5, NOx, and VOC in the 2012 PM2.5 Plan or 2015 

Supplement. We previously approved motor vehicle emissions 

budgets for the 1997 annual and 24-hour PM2.5 standards (76 FR 
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69928, 69951 (November 9, 2011)), and these budgets will 

continue to apply in the South Coast for transportation 

conformity purposes for these standards. The same budgets will 

also continue to apply for the 2006 24-hour PM2.5 standard until 

we finalize our approval of new budgets in the Serious area plan 

for the 2006 PM2.5 NAAQS or find those budgets adequate.60

J. General Conformity Budgets

1. Requirements for General Conformity

Conformity is required under CAA section 176(c) to ensure 

that federal actions are consistent with (‘‘conform to’’) the 

purpose of the SIP. Conformity to the purpose of the SIP means 

that federal activities will not cause new air quality 

violations, worsen existing violations, or delay timely 

attainment of the relevant NAAQS or interim reductions and 

milestones. Conformity applies to areas that are designated 

nonattainment and to maintenance areas.

Section 176(c)(4) of the CAA establishes the framework for 

general conformity. The EPA first promulgated general conformity 

 

60 In 2012, the EPA revised the annual PM2.5 standard, lowering its level from 

15 μg/m3 to 12 μg/m3 (78 FR 3086 (January 15, 2013). We finalized designations 

for the 2012 standard in December, 2014 and these designations became 

effective April 15, 2015. See 80 FR 2206, January 15, 2015. For purposes of 

the 2012 PM2.5 standard, the regional conformity test requirements for all 

nonattainment and maintenance areas in 40 CFR 93.109 will apply one year 

after the effective date of EPA’s nonattainment designations in accordance 

with section 93.102(d) and until the effective date of revocation of such 

NAAQS.
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regulations in November 1993 (40 CFR part 51, subpart W, 40 CFR 

part 93, subpart B). Subsequently we revised the general 

conformity regulations on April 5, 2010 (75 FR 17254). Besides 

ensuring that federal actions not covered by the transportation 

conformity rule will not interfere with the SIP, the general 

conformity regulations encourage consultation between the 

federal agency and the state or local air pollution control 

agencies before and during the environmental review process, as 

well as public notification of and access to federal agency 

conformity determinations, and allows for air quality review of 

individual federal actions.

The general conformity regulations provides three phases: 

(A) applicability analysis, (B) conformity determination, and 

(C) review process. The applicability analysis phase under 40 

CFR 93.153 is used to find if a Federal action requires a 

conformity determination for a specific pollutant. If a 

conformity determination is needed, Federal agencies can use one 

of several methods to show that the project conforms to the SIP. 

In an area without a State Implementation Plan (SIP), a federal 

action may be shown to "conform" by demonstrating there will be 

no net increase in emission in the nonattainment or maintenance 

area from the Federal action. 
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In an area with a SIP, conformity to the applicable SIP can 

be demonstrated in one of several ways. For actions where the 

direct and indirect emissions exceeds the rates in 40 CFR 

93.153(b), the federal action can include mitigation efforts to 

bring emissions to levels below the thresholds or can show that 

the action will conform by meeting any of the following 

requirements:

 By showing that the net emission increases caused by an 

action are included in the SIP,

 by documenting that the State agrees to include the 

emission increases in the SIP,

 through offsetting the action’s emissions in the same or 

nearby area of equal or greater classification, or

 through an air quality modeling demonstration in some 

circumstances.

The general conformity regulations at 40 CFR 93.161 allow 

state and local air quality agencies working with federal 

agencies with large facilities (e.g., commercial airports, ports 

and large military bases) that are subject to the general 

conformity regulations to develop and adopt an emissions budget 

for those facilities in order to facilitate future conformity 

determinations. Such a budget, referred to as a facility-wide 
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emission budget, may be used by federal agencies to demonstrate 

conformity as long as the total facility-wide budget level 

identified in the SIP is not exceeded.

According to 40 CFR 93.161, the state or local agency 

responsible for implementing and enforcing the SIP can develop 

and adopt an emissions budget to be used for demonstrating 

conformity under 40 CFR 93.158(a)(1). The facility-wide budget 

must (1) be for a set time period; (2) cover the pollutants or 

precursors of the pollutants for which the area is designated 

nonattainment or maintenance; (3) the budgets are specific about 

what can be emitted on an annual or seasonal basis; (4) the 

emissions from the facility along with all other emissions in 

the area will not exceed the total SIP emissions budget for the 

nonattainment or maintenance area; (5) specific measures are 

included to ensure compliance with the facility-wide budget, 

such as periodic reporting requirements or compliance 

demonstrations when the Federal agency is taking an action that 

would otherwise require a conformity determination; (6) the 

budget must be submitted to EPA as a SIP revision; and (7) the 

SIP revision must be approved by EPA. Having or using a 

facility-wide emissions budget does not preclude a Federal 
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agency from demonstrating conformity in any other manner allowed 

by the conformity rule.

2. General Conformity Budget in the 2012 PM2.5 Plan and 2015 

Supplement

The 2012 PM2.5 Plan addresses general conformity beginning 

on page II-2-52 of Appendix III. The District identified the de 

minimis thresholds for general conformity in the South Coast as 

10 tpy of VOC and NOx because of its designation and 

classification as a severe ozone nonattainment area, and 100 tpy 

of PM2.5 because of its designation and classification as a 

moderate PM2.5 nonattainment area. The District examined 

historical records and noted that projects requiring general 

conformity determinations had historically not exceeded the PM2.5

de minimis levels. The main pollutant of concern during project 

construction was NOx, and to a lesser extent, VOC. To streamline 

the general conformity process for projects and to facilitate 

general conformity determinations, VOC and NOx general 

conformity budgets of 1 tpd of NOx and 0.2 tpd of VOC were 

established on an annual basis from 2013 to 2030. These general 

conformity budgets will be tracked via a tracking system that 

the District sets up for projects subject to general conformity 

determinations. The District will count project emissions 
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towards the applicable general conformity budget until the 

budget has been exhausted. Any unused portions will not carry 

forward from year to year. Once the budget is exhausted, federal 

projects can still demonstrate conformity using other provisions 

in the conformity rule. 

3. Evaluation and Proposed Action

We propose to approve the general conformity budgets in the 

2012 PM2.5 Plan for NOx and VOC for 2013 to 2030 as meeting the 

requirements of the CAA and the general conformity rule. If we 

finalize our approval of these budgets, Federal agencies can use 

these budgets to demonstrate that their projects conform to the 

SIP through a letter from the state and District confirming that 

the project emissions are accounted for in the SIP’s general 

conformity budgets. The District will be responsible for 

tracking emissions from all projects against the budgets. Once 

the budgets are used, future federal projects will need to 

demonstrate conformity using a different method. Any federal 

projects that emit criteria pollutants or pollutant precursors 

other than those for which general conformity budgets are 

established will still need to demonstrate conformity for those 

pollutants or precursors. 
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V. Proposed Reclassification as Serious Nonattainment and 

Serious Area SIP Requirements

A. Proposed Reclassification as Serious and Applicable 

Attainment Date

Section 188 of the Act outlines the process for 

classification of PM2.5 nonattainment areas and establishes the 

applicable attainment dates. Under the plain meaning of the 

terms of section 188(b)(1) of the Act, the EPA has general 

authority to reclassify at any time before the applicable 

attainment date any area that the EPA determines cannot 

practicably attain the standard by such date. Accordingly, 

section 188(b)(1) of the Act is a general expression of 

delegated rulemaking authority. In addition, subparagraphs (A) 

and (B) of section 188(b)(1) mandate that the EPA reclassify 

“appropriate” PM10 nonattainment areas at specified time frames 

(i.e., by December 31, 1991 for the initial PM10 nonattainment 

areas, and within 18 months after the SIP submittal due date for 

subsequent nonattainment areas). These subparagraphs do not 

restrict the EPA’s general authority but simply specify that, at 

a minimum, it must be exercised at certain times.61

 

61 For a general discussion of EPA’s interpretation of the reclassification 

provisions in section 188(b)(1) of the Act, see the General Preamble, 57 FR 

13498 at 13537-38 (April 16, 1992).
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We have reviewed recent PM2.5 monitoring data for the South 

Coast available in the EPA’s Air Quality System (AQS) database. 

These data show that 24-hour PM2.5 levels in the South Coast 

continue to be above 35 μg/m3, the level of the 2006 PM2.5

standard, and the recent trends in the South Coast’s 24-hour 

PM2.5 levels are not consistent with a projection of attainment 

by the end of 2015. (See Memorandum dated August 21, 2015, 

Michael Flagg, US EPA Region 9, Air Quality Analysis Office). 

In accordance with section 188(b)(1) of the Act, the EPA is 

proposing to reclassify the South Coast area from Moderate to 

Serious nonattainment for the 2006 24-hour PM2.5 standard of 35 

μg/m3, based on the EPA’s determination that the South Coast area 

cannot practicably attain this standard by the applicable 

attainment date of December 31, 2015.

Under section 188(c)(2) of the Act, the attainment date for 

a Serious area “shall be as expeditiously as practicable but no 

later than the end of the tenth calendar year beginning after 

the area’s designation as nonattainment....” The South Coast area 

was designated nonattainment for the 2006 PM2.5 standard 

effective December 14, 2009.62 Therefore, upon final 

reclassification of the South Coast area as a Serious 

nonattainment area, the latest permissible attainment date under 

 

62 See 74 FR 58688 (November 13, 2009).
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section 188(c)(2) of the Act, for purposes of the 2006 PM2.5

standard in this area, will be December 31, 2019. 

Under section 188(e) of the Act, a state may apply to EPA 

for a single extension of the Serious area attainment date by up 

to 5 years, which the EPA may grant if the State satisfies 

certain conditions. Before the EPA may extend the attainment 

date for a Serious area under section 188(e), the State must: 

(1) apply for an extension of the attainment date beyond the 

statutory attainment date; (2) demonstrate that attainment by 

the statutory attainment date is impracticable; (3) have 

complied with all requirements and commitments pertaining to the 

area in the implementation plan; (4) demonstrate to the 

satisfaction of the Administrator that the plan for the area 

includes the most stringent measures that are included in the 

implementation plan of any State or are achieved in practice in 

any State, and can feasibly be implemented in the area; and (5) 

submit a demonstration of attainment by the most expeditious 

alternative date practicable.63

 

63 For a discussion of EPA’s interpretation of the requirements of section 

188(e), see “State Implementation Plans for Serious PM10 Nonattainment Areas, 

and Attainment Date Waivers for PM10 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) (hereafter “Addendum”) 

at 42002; 65 FR 19964 (April 13, 2000) (proposed action on PM10 Plan for 

Maricopa County, Arizona); 66 FR 50252 (October 2, 2001) (proposed action on 

PM10 Plan for Maricopa County, Arizona); 67 FR 48718 (July 25, 2002) (final 

action on PM10 Plan for Maricopa County, Arizona); and Vigil v. EPA, 366 F.3d 

1025, amended at 381 F.3d 826 (9th Cir. 2004) (remanding EPA action on PM10

Plan for Maricopa County, Arizona but generally upholding EPA’s 

interpretation of CAA section 188(e)).
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B. Clean Air Act Requirements for Serious PM2.5 Nonattainment 

Area Plans

Upon reclassification as a Serious nonattainment area for 

the 2006 PM2.5 NAAQS, California will be required to submit 

additional SIP revisions to satisfy the statutory requirements 

that apply to Serious PM2.5 nonattainment areas, including the 

requirements of subpart 4 of part D, title I of the Act.

The Serious area SIP elements that California will be 

required to submit are as follows:

1. provisions to assure that the best available control 

measures (BACM), including best available control 

technology (BACT) for stationary sources, for the control 

of direct PM2.5 and PM2.5 precursors shall be implemented 

no later than 4 years after the area is reclassified (CAA 

section 189(b)(1)(B));

2. a demonstration (including air quality modeling) that the 

plan provides for attainment as expeditiously as 

practicable but no later than December 31, 2019, or where 

the State is seeking an extension of the attainment date 

under section 188(e), a demonstration that attainment by 

December 31, 2019 is impracticable and that the plan 

provides for attainment by the most expeditious 
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alternative date practicable and no later than December 

31, 2024 (CAA sections 188(c)(2) and 189(b)(1)(A)); 

3. plan provisions that require reasonable further progress 

(RFP) (CAA 172(c)(2));

4. quantitative milestones which are to be achieved every 3 

years until the area is redesignated attainment and which 

demonstrate RFP toward attainment by the applicable date 

(CAA section 189(c)); 

5. provisions to assure that control requirements applicable 

to major stationary sources of PM2.5 also apply to major 

stationary sources of PM2.5 precursors, except where the 

state demonstrates to the EPA’s satisfaction that such 

sources do not contribute significantly to PM2.5 levels 

that exceed the standard in the area (CAA section 

189(e));

6. a comprehensive, accurate, current inventory of actual 

emissions from all sources of PM2.5 and PM2.5 precursors in 

the area (CAA section 172(c)(3));

7. contingency measures to be implemented if the area fails 

to meet RFP or to attain by the applicable attainment 

date (CAA section 172(c)(9)); and 
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8. A revision to the nonattainment new source review (NSR) 

program to lower the applicable “major stationary 

source”64 thresholds from 100 tons per year (tpy) to 70 

tpy (CAA section 189(b)(3)).

Final reclassification of the South Coast area as Serious 

nonattainment for the 2006 PM2.5 standard may also lower the de 

minimis threshold under the CAA’s General Conformity 

requirements (40 CFR part 93, subpart B) from 100 tpy to 70 tpy 

for PM2.5 and PM2.5 precursors. See 80 FR 15339 at 15441.

In March of 2015, the EPA issued a proposed rulemaking to

provide guidance to states on the attainment planning 

requirements in subparts 1 and 4 of part D, title I of the Act 

that apply to areas designated nonattainment for PM2.5.65 In the 

interim, before the PM2.5 implementation rule is finalized, the 

EPA encourages the State to review the proposed rulemaking as 

well as the General Preamble and Addendum for guidance on how to 

implement these statutory requirements in the South Coast PM2.5

nonattainment area.66

 

64 For any Serious area, the terms “major source” and “major stationary 

source” include any stationary source that emits or has the potential to emit 

at least 70 tons per year of PM10 (CAA sections 189(b)(3)).

65 See 80 FR 15339, “Fine Particulate Matter National Ambient Air Quality 

Standards: State Implementation Plan Requirements,” March 23, 2015.

66 See generally the General Preamble, 57 FR 13498 (April 16, 1992) and 

Addendum, 59 FR 41998 (August 16, 1994).
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C. Statutory Deadline for Submittal of the Serious Area Plan

For an area reclassified as a Serious nonattainment area 

before the applicable attainment date under CAA section 

188(b)(1), section 189(b)(2) requires the State to submit the 

required BACM provisions “no later than 18 months after 

reclassification of the area as a Serious Area” and to submit 

the required attainment demonstration “no later than 4 years 

after reclassification of the area to Serious.” Section 

189(b)(2) establishes outer bounds on the SIP submission 

deadlines and does not preclude the EPA’s establishment of 

earlier deadlines as necessary or appropriate to assure 

consistency among the required submissions and to implement the 

statutory requirements.

If a final reclassification of the South Coast PM2.5

nonattainment area to Serious becomes effective by early 2016, 

the Act provides the State with up to 18 months after this date 

(i.e., until mid-2017) to submit the required BACM provisions. 

Because an up-to-date emissions inventory serves as the 

foundation for a state’s BACM and BACT determinations, the EPA 

also proposes to require the State to submit the emissions 

inventory required under CAA section 172(c)(3) within 18 months 

after the effective date of final reclassification. Similarly, 

because an effective evaluation of BACM and BACT measures 
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requires evaluation of the precursor pollutants that must be 

controlled to provide for expeditious attainment in the area, if 

the State chooses to submit an optional precursor insignificance 

demonstration to support a determination to exclude a PM2.5

precursor from the required control measure evaluations for the 

area, the EPA proposes to require the State to submit any such 

demonstration by this same date. An 18-month timeframe for 

submission of these plan elements is consistent with both the 

timeframe for submission of BACM provisions under CAA section 

189(b)(2) and the timeframe for submission of subpart 1 plan 

elements under section 172(b) of the Act.67

The EPA proposes to require the State to submit the 

attainment demonstration required under section 189(b)(1)(A) and 

the remaining attainment-related plan elements no later than 

three years after the effective date of final reclassification 

or by December 31, 2018, whichever is earlier. The attainmentrelated plan elements that we propose to require within the same 

3-year timeframe as the attainment demonstration are: (1) the 

RFP demonstration required under section 172(c)(2); (2) the 

quantitative milestones required under section 189(c); (3) any 

 

67 Section 172(b) requires the EPA to establish, concurrent with nonattainment 

area designations, a schedule extending no later than 3 years from the date 

of the nonattainment designation for states to submit plans or plan revisions 

meeting the applicable requirements of sections 110(a)(2) and 172(c) of the 

CAA.
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additional control measures necessary to meet the requirements 

of section 172(c)(6); and (4) the contingency measures required 

under section 172(c)(9). Although section 189(b)(2) generally 

provides for up to 4 years after a discretionary 

reclassification for the State to submit the required attainment 

demonstration, it is appropriate in this case for the EPA to 

establish an earlier SIP submission deadline to assure timely 

implementation of the statutory requirements. 

The EPA designated the South Coast area as nonattainment 

for the 2006 PM2.5 standard effective December 14, 2009.68 On 

January 4, 2013, the D.C. Circuit Court of Appeals issued its 

decision in NRDC remanding EPA’s 2007 PM2.5 Implementation Rule 

and directing the EPA to repromulgate it in accordance with the 

requirements of subpart 4.69 In response to the NRDC decision, 

the EPA undertook a rulemaking to classify all PM2.5

nonattainment areas as Moderate nonattainment and begin 

implementing the PM2.5 NAAQS under subpart 4. Effective July 2, 

2014, the EPA classified all areas previously designated 

nonattainment for the 1997 and/or 2006 PM2.5 NAAQS as Moderate 

nonattainment under subpart 4 and established a December 31, 

2014 deadline for states to submit Moderate area SIP elements 

 

68 74 FR 58688 (November 13, 2009).

69 NRDC v. EPA, 706 F.3d 428 (D.C. Cir. 2013). 
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required for these areas.70 These unusual circumstances have 

significantly shortened the timeframes ordinarily allowed under 

the Act for the EPA and the states to address the statutory SIP 

requirements following reclassification of an area from Moderate 

to Serious nonattainment under subpart 4.71

Our proposal to require the State to submit the attainment 

demonstration and other attainment-related plan elements no 

later than three years after reclassification or by December 31, 

2018, whichever is earlier, is supported by the overall 

structure and purpose of the attainment planning requirements in 

part D, title I of the Act. Section 188(b)(1) provides the EPA 

with discretionary authority to reclassify an area as Serious 

nonattainment at any time before the applicable attainment date, 

based on a determination that the area cannot practicably attain 

the NAAQS by the Moderate area attainment date. Under normal 

 

70 79 FR 31566 (June 2, 2014). The EPA notes that some states had already made 

SIP submissions intended to meet applicable nonattainment plan requirements 

as interpreted in the remanded 2007 PM2.5 Implementation Rule. Accordingly, 

the new SIP submission deadline provided the opportunity for states to revise 

or supplement their prior submissions, as necessary or appropriate to meet 

subpart 4 requirements.

71 For areas designated nonattainment after November 15, 1990, section 

188(b)(1)(B) of the Act requires that the EPA “reclassify appropriate areas 

within 18 months after the required date for the State’s submission of a SIP 

for the Moderate Area.” Read together with section 189(a)(2)(B), which 

requires states to submit Moderate Area plans within 18 months after 

nonattainment designations, section 188(b)(1)(B) generally contemplates that 

EPA would reclassify appropriate areas as Serious nonattainment no later than 

36 months (3 years) after initial nonattainment designations. Under these 

circumstances, the required Serious area attainment demonstration would 

normally be submitted no later than 7 years after initial designation (4 

years after reclassification), which is 3 years before the latest permissible 

attainment date under CAA section 188(c)(2).
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circumstances, where the EPA reclassifies an area within 3 years 

after its designation as nonattainment, as contemplated in CAA 

section 188(b)(1)(B),72 the required BACM provisions would be due 

no later than 18 months after reclassification (i.e., no later 

than 4.5 years after designation) and the required attainment 

demonstration would be due no later than 4 years after 

reclassification (i.e., no later than 7 years after 

designation).73 In these circumstances, the Serious area 

attainment demonstration would be due at least 3 years before 

the outermost Serious area attainment date for the area,74 thus 

providing the EPA with sufficient time to evaluate the submitted 

plan well in advance of the statutory attainment date. However, 

in situations such as this, where the EPA reclassifies an area 

pursuant to its discretionary reclassification authority later

than 3 years after the area’s designation as nonattainment, it 

is appropriate for the EPA to consider the outermost Serious 

area attainment date applicable to the area in setting a 

 

72 Id.

73 CAA section 189(b)(2). By contrast, for an area that is reclassified as 

Serious by operation of law after the applicable attainment date, which may 

be as late as the end of the 6th year after the area’s designation as 

nonattainment (CAA section 188(b)(1)), the state must submit both the BACM 

provisions and the Serious area attainment demonstration no later than 18 

months after reclassification. Id.

74 Under CAA section 188(c)(2), the latest permissible attainment date for a 

Serious PM2.5 nonattainment area is no later than the end of the tenth calendar 

year beginning after the area’s designation as nonattainment.
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deadline for the State to submit the required elements of the 

Serious area attainment plan. 

Upon reclassification as Serious, the South Coast PM2.5

nonattainment area will be subject to a Serious area attainment 

date no later than December 31, 2019.75 Sections 189(b)(1)(A) 

and 189(c) of the Act require the State to submit a 

demonstration that the plan provides for attainment of the PM2.5

standard by this date, including quantitative milestones which 

are to be achieved every 3 years until the area is redesignated 

attainment and which demonstrate reasonable further progress 

toward attainment by this date. If the EPA reclassifies the 

South Coast area effective in early 2016 and allows the State 4 

years following reclassification (i.e., potentially until early 

2020) to submit the attainment demonstration and related plan 

elements, these Serious area plan provisions would not be due 

until after the latest permissible statutory attainment date for 

the area (December 31, 2019) has come and gone. Thus, under 

such circumstances, allowing the maximum 4-year timeframe for 

submission of the required attainment demonstration and related 

plan elements would frustrate the statutory design and severely 

constrain the EPA’s ability to ensure that the State is 

 

75 Id.
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implementing the applicable statutory requirements in a timely 

manner. 

Therefore, it is appropriate for the EPA to require 

California to submit the required attainment demonstration and 

other attainment-related plan elements no later than 3 years 

after final reclassification or by December 31, 2018, whichever 

is earlier, so that the EPA has adequate time to review and act 

on the State’s submission prior to the latest permissible 

attainment date for the area under section 188(c)(2), which is 

December 31, 2019. This timeframe for the required Serious area 

plan submissions is appropriate to assure consistency among the

required submissions and to implement the statutory requirements 

in a timely manner.

Finally, the EPA proposes to require that the State submit 

revised nonattainment NSR program requirements no later than 18 

months after final reclassification. The Act does not specify a 

deadline for the State’s submission of SIP revisions to meet 

nonattainment NSR program requirements to lower the “major 

stationary source” threshold from 100 tons per year (tpy) to 70 

tpy (CAA section 189(b)(3)) and to address the control

requirements for major stationary sources of PM2.5 precursors 

(CAA section 189(e))76 following reclassification of a Moderate 

 

76 Section 189(e) requires that the control requirements applicable to major 

stationary sources of PM2.5 also apply to major stationary sources of PM2.5
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PM2.5 nonattainment area as Serious nonattainment under subpart 

4. Pursuant to the EPA’s gap-filling authority in CAA section 

301(a) and to effectuate the statutory control requirements in 

section 189 of the Act, the EPA proposes to require the State to 

submit these nonattainment NSR SIP revisions, as well as any 

necessary analysis of and additional control requirements for 

major stationary sources of PM2.5 precursors, no later than 18 

months after the effective date of final reclassification of the 

South Coast area as Serious nonattainment for the 2006 PM2.5

standard. This due date will ensure that necessary control 

requirements for major sources are established well in advance 

of the required attainment demonstration. An 18-month timeframe 

for submission of the NNSR SIP revisions also aligns with the 

statutory deadline for submission of BACM and BACT provisions 

and the broader analysis of PM2.5 precursors for potential 

controls on existing sources in the area. 

VI. Reclassification of Reservation Areas of Indian Country

Seven Indian tribes are located within the boundaries of 

the South Coast PM2.5 nonattainment area. These tribes are listed 

in Table 4 below.

 

precursors, except where the state demonstrates to the EPA’s satisfaction 

that such sources do not contribute significantly to PM2.5 levels that exceed 

the standard in the area.
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Table 4. Indian Tribes Located in South Coast PM2.5

Nonattainment Area

Cahuilla Band of Indians

Morongo Band of Cahuilla Mission Indians

Pechanga Band of Luiseno Mission Indians of the Pechanga 

Reservation

Ramona Band of Cahuilla

San Manuel Band of Serrano Mission Indians of the San 

Manuel Reservation

Santa Rosa Band of Cahuilla Indians

Soboba Band of Luiseno Indians

We have considered the relevance of our proposal to 

reclassify the South Coast area as Serious nonattainment for the 

2006 PM2.5 standard to each tribe located within the South Coast

area. We believe that the same facts and circumstances that 

support the proposal for the non-Indian country lands also 

support the proposal for reservation areas of Indian country77

and any other area of Indian country where the EPA or a tribe 

has demonstrated that the tribe has jurisdiction located within 

the South Coast nonattainment area. The EPA is therefore 

proposing to exercise our authority under CAA section 188(b)(1) 

 

77 “Indian country” as defined at 18 U.S.C. 1151 refers to: “(a) all land 

within the limits of any Indian reservation under the jurisdiction of the 

United States Government, notwithstanding the issuance of any patent, and, 

including rights-of-way running through the reservation, (b) all dependent 

Indian communities within the borders of the United States whether within the 

original or subsequently acquired territory thereof, and whether within or 

without the limits of a state, and (c) all Indian allotments, the Indian 

titles to which have not been extinguished, including rights-of-way running 

through the same.” 
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to reclassify areas of Indian country geographically located in 

the South Coast nonattainment area. Section 188(b)(1) broadly 

authorizes the EPA to reclassify a nonattainment area –

including any Indian country located within such an area – that 

EPA determines cannot practicably attain the relevant standard 

by the applicable attainment date.

Directly-emitted PM2.5 and its precursor pollutants (NOx, 

SO2, VOC, and ammonia) are emitted throughout a nonattainment 

area and can be transported throughout that nonattainment area. 

Therefore, boundaries for nonattainment areas are drawn to 

encompass both areas with direct sources of the pollution 

problem as well as nearby areas in the same airshed. Initial 

classifications of nonattainment areas are coterminous with, 

that is, they match exactly, their boundaries. The EPA believes 

this approach best ensures public health protection from the 

adverse effects of PM2.5 pollution. Therefore, it is generally 

counterproductive from an air quality and planning perspective 

to have a disparate classification for a land area located 

within the boundaries of a nonattainment area, such as the 

reservation areas of Indian country contained within the South 

Coast PM2.5 nonattainment area. Moreover, violations of the 2006 

PM2.5 standard, which are measured and modeled throughout the 

nonattainment area, as well as shared meteorological conditions, 
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would dictate the same conclusion. Furthermore, emissions 

increases in portions of a PM2.5 nonattainment area that are left 

classified as Moderate could counteract the effects of efforts 

to attain the standard within the overall area because less 

stringent requirements would apply in those Moderate portions

relative to those that would apply in the portions of the area 

reclassified to Serious. 

Uniformity of classification throughout a nonattainment 

area is thus a guiding principle and premise when an area is 

being reclassified. Equally, if the EPA believes it is likely 

that a given nonattainment area will not attain the PM2.5

standard by the applicable attainment date, then it may be an 

additional reason why it is appropriate to maintain a uniform 

classification within the area and thus to reclassify the 

reservation areas of Indian country and any other area where the 

EPA or a tribe has demonstrated that a tribe has jurisdiction

together with the balance of the nonattainment area. In this 

particular case, we are proposing to determine, based on the 

State’s demonstration and current ambient air quality trends, 

that the South Coast nonattainment area cannot practicably 

attain the 2006 PM2.5 standard by its applicable Moderate area 

attainment date of December 31, 2015. 
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In light of the considerations outlined above that support 

retention of a uniformly-classified PM2.5 nonattainment area, and

our finding that it is impracticable for the area to attain by 

the applicable attainment date, we propose to reclassify the

areas of Indian country within the South Coast nonattainment 

area as Serious nonattainment for the 2006 PM2.5 standard.

The effect of reclassification would be to lower the 

applicable “major source” threshold for purposes of the 

nonattainment new source review program and the Title V 

operating permit program from its current level of 100 tpy to 70 

tpy (CAA sections 189(b)(3) and 501(2)(B)), thus subjecting more 

new or modified stationary sources to these requirements. The 

reclassification may also lower the de minimis threshold under 

the CAA’s General Conformity requirements (40 CFR part 93, 

subpart B) from 100 tpy to 70 tpy. Under the General Conformity 

requirements, Federal agencies bear the responsibility of 

determining conformity of actions in nonattainment and 

maintenance areas that require Federal permits, approvals, or 

funding. Such permits, approvals or funding by Federal agencies 

for projects in these areas of Indian country may be more 

difficult to obtain because of the lower de minimis thresholds. 

Given the potential implications of the reclassification, 

the EPA has contacted tribal officials to invite government-to-
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government consultation on this rulemaking effort.78 The EPA 

specifically solicits additional comment on this proposed rule 

from tribal officials. We note that although eligible tribes may 

seek EPA approval of relevant tribal programs under the CAA, 

none of the affected tribes will be required to submit an 

implementation plan to address this reclassification.

VII. Summary of Proposed Actions and Request for Public Comment

Under CAA section 110(k)(3), the EPA is proposing to 

approve the following elements of the 2012 PM2.5 Plan and 2015 

Supplement submitted by California to address the CAA’s Moderate 

area planning requirements for the 2006 PM2.5 NAAQS in the South 

Coast nonattainment area:

1. the 2008 base year emissions inventories as meeting 

the requirements of CAA section 172(c)(3);

2. the reasonably available control measures/reasonably 

available control technology demonstration as meeting the 

requirements of CAA sections 172(c)(1) and 189(a)(1)(C);

3. the reasonable further progress demonstration as 

meeting the requirements of CAA section 172(c)(2);

 

78 We sent letters to seven tribal officials regarding government-togovernment consultation on September 4, 2015 and September 30, 2015. 
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4. the demonstration that attainment by the Moderate area 

attainment date of December 31, 2015 is impracticable as 

meeting the requirements of CAA section 189(a)(1)(B)(ii); and

5. SCAQMD's commitments to adopt and implement specific 

rules and measures in accordance with the schedule provided in

Chapter 4 of the 2012 PM2.5 Plan, as revised by Table F-1 of 

Attachment F of the 2015 Supplement, to achieve the emissions 

reductions shown therein, and to submit these rules and measures

to ARB for transmittal to EPA as a revision to the SIP, as 

stated on pp. 7-8 of SCAQMD Governing Board Resolution 12-19.

In addition, the EPA is proposing to approve the general 

conformity budgets for NOx and VOC for years 2013-2030 listed in 

Appendix III, p. III-2-53 of the 2012 PM2.5 Plan as meeting the 

requirements of the CAA and the general conformity rule. 

Finally, pursuant to CAA section 188(b)(1), the EPA is 

proposing to reclassify the South Coast PM2.5 nonattainment 

area, including the reservation areas of Indian country and any

other area where the EPA or a tribe has demonstrated that a 

tribe has jurisdiction within the South Coast area, as Serious 

nonattainment for the 2006 PM2.5 standard based on the agency’s 

determination that the South Coast area cannot practicably 

attain the standard by the Moderate area attainment date of 
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December 31, 2015. Upon final reclassification as a Serious 

area, California will be required to submit, within 18 months

after the effective date of the reclassification, provisions to 

assure that BACM shall be implemented no later than 4 years 

after the date of reclassification and to submit, within 3 years 

after the effective date of reclassification or by December 31, 

2018, which is sooner, a Serious area plan that satisfies the 

requirements of part D of title I of the Act. This plan must

include a demonstration that the South Coast area will attain

the 2006 PM2.5 standard as expeditiously as practicable but no 

later than December 31, 2019, or by the most expeditious 

alternative date practicable and no later than December 31, 

2024, in accordance with the requirements of CAA sections 189(b) 

and 188(e). 

In addition, because the EPA is proposing to similarly 

reclassify reservation areas of Indian country and any other 

area of Indian country where EPA or a tribe has demonstrated 

that the tribe has jurisdiction within the South Coast PM2.5 

nonattainment area as Serious nonattainment for the 2006 PM2.5 

standard, consistent with our proposed reclassification of the 

surrounding non-Indian country lands, the EPA has invited 

consultation with interested tribes concerning this issue. We 
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note that although eligible tribes may seek the EPA’s approval 

of relevant tribal programs under the CAA, none of the affected 

tribes will be required to submit an implementation plan to 

address this reclassification.

We will accept comments from the public on these proposals

for the next 30 days. The deadline and instructions for 

submission of comments are provided in the ‘‘Dates’’ and 

‘‘Addresses’’ sections at the beginning of this preamble.

VI. Statutory and Executive Order Reviews

Additional information about these statutes and Executive 

Orders can be found at http://www2.epa.gov/lawsregulations/laws-and-executive-orders. 

A. Executive Order 12866: Regulatory Planning and Review, and 

Executive Order 13563: Improving Regulation and Regulatory 

Review

This action is not a significant regulatory action and was 

therefore not submitted to the Office of Management and Budget 

(OMB) for review. 

B. Paperwork Reduction Act (PRA)

This action does not impose an information collection 

burden under the PRA because it does not contain any information 

collection activities. 
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C. Regulatory Flexibility Act (RFA)

I certify that this action will not have a significant 

economic impact on a substantial number of small entities under 

the RFA. This action will not impose any requirements on small 

entities. This proposed action would approve State law as 

meeting Federal requirements and would not impose additional 

requirements beyond those imposed by State law. Additionally, 

the proposed rule would reclassify the South Coast nonattainment 

area as Serious nonattainment for the 2006 PM2.5 NAAQS, and would 

not itself regulate small entities.

D. Unfunded Mandates Reform Act (UMRA)

This action does not contain an unfunded mandate of $100 

million or more as described in UMRA, and does not significantly 

or uniquely affect small governments. This proposed action would 

approve State law as meeting Federal requirements and would not 

impose additional requirements beyond those imposed by State 

law. Additionally, the proposed action would reclassify the 

South Coast nonattainment area as Serious nonattainment for the 

2006 PM2.5 NAAQS, and would not itself impose any federal 

intergovernmental mandate. The proposed action would not require 

any tribes to submit implementation plans.

E. Executive Order 13132: Federalism
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This action does not have federalism implications. It will 

not have substantial direct effects on the states, on the 

relationship between the national government and the states, or 

on the distribution of power and responsibilities among the 

various levels of government.

F. Executive Order 13175: Coordination with Indian Tribal 

Governments

Executive Order 13175, entitled ‘‘Consultation and 

Coordination with Indian Tribal Governments’’ (65 FR 67249, 

November 9, 2000), requires the EPA to develop an accountable 

process to ensure ‘‘meaningful and timely input by tribal 

officials in the development of regulatory policies that have 

tribal implications.’’ ‘‘Policies that have Tribal implications’’

is defined in the Executive Order to include regulations that 

have ‘‘substantial direct effects on one or more Indian tribes, 

on the relationship between the Federal government and the 

Indian tribes, or on the distribution of power and 

responsibilities between the Federal government and Indian 

Tribes.’’

Seven Indian tribes are located within the boundaries of 

the South Coast nonattainment area for the 2006 PM2.5 NAAQS: the 

Cahuilla Band of Indians, the Morongo Band of Cahuilla Mission 

Indians, the Pechanga Band of Luiseno Mission Indians of the 
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Pechanga Reservation, the Ramona Band of Cahuilla, the San 

Manuel Band of Serrano Mission Indians of the San Manuel 

Reservation, the Santa Rosa Band of Cahuilla Indians, and the 

Soboba Band of Luiseno Indians. 

The SIP is not approved to apply on any Indian reservation 

land or in any other area where EPA or an Indian tribe has 

demonstrated that a tribe has jurisdiction. In those areas of 

Indian country, the rule does not have tribal implications and 

will not impose substantial direct costs on tribal governments 

or preempt tribal law as specified by Executive Order 13175 (65 

FR 67249, November 9, 2000).

The EPA has concluded that this proposed rule might have 

tribal implications for the purposes of Executive Order 13175, 

but would not impose substantial direct costs upon the tribes, 

nor would it preempt Tribal law. We note that only one of the 

tribes located in the South Coast nonattainment area (the 

Pechanga Band of Luiseno Mission Indians of the Pechanga 

Reservation) has requested eligibility to administer programs 

under the CAA. The proposed rule would affect the EPA’s 

implementation of the new source review program because of the 

lower “major source” threshold triggered by reclassification (70 

tons per year for direct PM2.5 and precursors to PM2.5). The 

proposed rule may also affect new or modified stationary sources 

proposed in these areas that require Federal permits, approvals, 
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or funding. Such projects are subject to the requirements of 

EPA’s General Conformity rule, and Federal permits, approvals, 

or funding for the projects may be more difficult to obtain 

because of the lower de minimis thresholds triggered by 

reclassification. 

Given the potential implications, the EPA contacted tribal 

officials during the process of developing this proposed rule to 

provide an opportunity to have meaningful and timely input into 

its development. On September 4, 2015, we sent letters to 

leaders of the seven tribes with areas of Indian country in the 

South Coast nonattainment area inviting government-to-government 

consultation on the rulemaking effort. We requested that the 

tribal leaders, or their designated consultation 

representatives, provide input or request government-togovernment consultation by October 4, 2015. We intend to 

continue communicating with all seven tribes located within the 

boundaries of the South Coast nonattainment area for the 2006 

PM2.5 NAAQS as we move forward in developing a final rule. The 

EPA specifically solicits additional comment on this proposed 

rule from tribal officials.

G. Executive Order 13045, Protection of Children from 

Environmental Health Risks and Safety Risks
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The EPA interprets Executive Order 13045 as applying only 

to those regulatory actions that concern environmental health or 

safety risks that the EPA has reason to believe may 

disproportionately affect children, per the definition of 

‘‘covered regulatory action’’ in section 2-202 of the Executive 

Order. This proposed action is not subject to Executive Order 

13045 because it would approve a state action implementing a 

federal standard, and reclassify the South Coast nonattainment 

area as Serious nonattainment for the 2006 PM2.5 NAAQS, 

triggering Serious area planning requirements under the CAA. 

This proposed action does not establish an environmental 

standard intended to mitigate health or safety risks. 

H. Executive Order 13211, Actions that Significantly Affect 

Energy Supply, Distribution, or Use

This proposed action is not subject to Executive Order

13211, because it is not a significant regulatory action under 

Executive Order 12866.

I. National Technology Transfer and Advancement Act

This rulemaking does not involve technical standards. 

J. Executive Order 12898: Federal Actions to Address 

Environmental Justice in Minority Populations and Low-Income 

Population
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The EPA has determined that this action will not have 

potential disproportionately high and adverse human health or 

environmental effects on minority or low-income populations 

because it does not affect the level of protection provided to 

human health or the environment. This proposed action would only 

approve a state action implementing a federal standard, and 

reclassify the South Coast nonattainment area as Serious 

nonattainment for the 2006 PM2.5 NAAQS, triggering additional 

Serious area planning requirements under the CAA.

List of Subjects in 40 CFR Part 52

Environmental protection, Air pollution control, incorporation 

by reference, Intergovernmental relations, Oxides of nitrogen, 

Particulate matter, Reporting and recordkeeping requirements, 

Sulfur Oxides, Volatile organic compounds.

AUTHORITY: 42 U.S.C. 7401 et seq. 

______September 30, 2015___ ______/s/_______________________

Dated: Jared Blumenfeld,

Regional Administrator,

EPA Region 9