# Technical Support Document

for the Proposed Action on the South Coast

20 12 PM 2.5 

## Plan and 2015 Supplement and Proposed

Reclassification of the South Coast as Serious

Nonattainment for the 2006 PM 2.5 

## Standard

Air Division U.S. EPA Region 9 September 201 5For further information on this technical support document, please contact:

Wienke Tax Office of Air Planning (AIR

- 2)

U.S. Environmental Protection Agency

- Region 9

75 Hawthorne Street San Francisco, California 94105 (415) 9 4 7

- 41 9 2

Tax.wienke @epa.gov

D ocuments referenced in this technical support document may be found in the docket for this rulemaking , docket no. EPA

- R09

- OAR

- 20 1 5

- 0204

, which may be found at www.regulations.gov

or at the address listed above

.

## Table of Contents

I. Background and SIP Submittals 5

A. History of PM 2.5 NAAQS Implementation and PM 2.5 Planning in the South Coast 5

B. PM 2.5 Air Quality Data for the South Coast Air Basin 9

C. California SIP Submittals for the 2006 PM 2.5 Standard in the South Coast 1 5

D. Public Notice and Hearing Requirements for and Completeness of SIP Submittals 1 6

II. Evaluation of the South Coast 2012 PM 2.5 Plan and 2015 Supplement 2 1

A. Emissions Inventories 22

B. Air Quality Modeling 26

C

. PM 2.5 Precursors 51

D. Reasonably Available Control Measures/Reasonably Available Control Technology (RACM/RACT) 54

E. Major Stationary Source Control Requirements Under CAA Section 189(e) 63

F. Adopted Control Strategy 64

G. Demonstration of Impracticability 69

H. Reasonable Further Progress and Quantitative Milestones 72

I. Contingency Measures 76

J. Motor Vehicle Emissions Budgets 78

K. General Conformity Budgets 80

III. Proposed Reclassification as Serious Nonattainment and Serious Area SIP Requirements 84

A. Proposed Reclassification as Serious and Applicable Attainment D ate 85

B. Clean Air Act Requirements for Serious PM 2.5 Nonattainment Areas 86

C. Statutory Deadline for Submittal of a Serious Area Plan 87

D. Reclassification of Reservation Areas of Indian Country 91

## Acronyms and Abbreviations

μ: micron (one millionth)

AB: California Assembly Bill

AERR: Air Emissions Report Rule, 40 CFR part 51, subpart A

ARB: California Air Resources Board (also CARB)

APCD: air pollution control district AQMD: air quality managemen t district

CARB: California Air Resources Board (also ARB)

CCR: California Code of Regulations

CERR: Consolidated Emissions Reporting Rule, 40 CFR part 51, subpart A

CFR: Code of Federal Regulations CMAQ: Congestion Mitigation and Air Quality funds CMAQ: Community Multiscale Air Quality [model]

CMB: c hemical mass balance

CPM: condensable particulate matter CRPAQS: California Regional Particulate Air Quality Study

District: South Coast Air Quality Management District

EC: elemental carbon

EPA: United States Environmental Protection Agency

FHWA: Federal Highway Administration Fine particulate: PM 2.5 FMVCP: Federal motor vehicle control program

FR: Federal Register

FRM: Federal Reference Method

FTA: Federal Transit Administration

HNO 3 : nitric acid

I/C: internal combustion

km: kilometer

m: meter

m 3 : cubic meter

mb: millibars

MFB: mean fractional bias

MFE : mean fractional error

MM5: a mesoscale model

MMP A : m eteorological m odel p erformance a nalysis

MOZART: Model for Ozone And Related C hemical Tracers

MPO: metropolitan planning organization

MVEB: motor vehicle emissions budget NAAQS: national ambient air quality standard

NH 3 : ammonia

NH 4 NO 3 : ammonium nitrate

NNSR: nonattainment new source review

NO 2 : nitrogen dioxide

## Acronyms and Abbreviations

NO
x : oxides of nitrogen

NSR: new source review NYQ: not yet quantified

O 3 : ozone OC: organic carbon

OH: hydroxyl radical OTAQ: EPA’s Office of Transportation and Air Quality

PBL: p lanetary b oundary l ayer PM: particulate matter

PM 10 : particulate matter with a diameter of 10 μm or less, includes PM 2.5 PM 2.5 : particulate matter with a diameter of 2.5 μm or less

PMC: coarse particulate matter

PMF: positive matrix factorization

RACM: reasonably available control measures

RACT: reasonably available control technology

RFP : reasonable further progress

R MD: Receptor Modeling Documentation

RMPA: Regional Modeling Performance Analysis

RRF: r elative response factor

RTP: regional transportation plan

SANDWICH : S ulfate , adjusted nitrate, derived water, inferred carbonaceous material balance approach

SC: South Coast SCAQMD: South Coast Air Quality Management District

SIP: state implementation plan

SJV: San Joaquin Valley

SJVAPCD /SJVUAPCD : San Joaquin Valley (Unified) Air Pollution Control District

SMAT: Speciated Modeled Attainment Test

SO 2 : sulfur dioxide

SOA: secondary organic aerosol

STN: Speciation Trends Network

SO
x : oxides of sulfur

TCM: transportation control measures tpd: tons per day

TIP: transportation improvement program

TSD: technical support document

VMT: vehicle miles traveled

VOC: vola tile organic compounds

WOE: weight of evidence WRF: Weather Research and Forecasting ModelTSD

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## Technical Support Document

for the Proposed Action on the South Coast

20 12 PM 2.5 

## Plan and 2015 Supplement and Proposed

Reclassification of the South Coast as Serious

Nonattainment for the 2006 PM 2.5 

## Standard

This document provides i nformation and analysis supporting the EPA’s proposed approval of the portions of the South Coast Air Quality Manag e ment District’s Final 20 12 Air Quality Management Plan (December 2012) (“2012 PM 2.5 Plan”) and Supplement to the 24

- Hour P M 2.5 State Implementation Plan for the South Coast Air Basin , January 2015 (“ 2015 Supplement ”) that address attainment of the 2006 P M 2.5 NAAQS and EPA’s proposed

reclassification of the South Coast as Serious nonattainment for the 2006 PM 2.5 standard

. The

2012 PM 2.5 Plan and 2015 Supplement address the Clean Air Act’s requirements for attainment

of the 2006 24

- hour PM 2.5 national ambient air quality standard in areas designated as

nonattainment and classified as moderate. The South Coast is c urrently designated nonattainment

and classified as moderate for the 2006 PM 2.5 standard

. See 79 FR 31566 (June 2, 2014) and 40 CFR § 81.305. 1



## I. Background and SIP Submittals

A. History of PM 2.5 

### NAAQS Implementation and PM 2.5 

### Plan ni ng in the S outh

Coast

On July 18, 1997, the EPA revised the primary and secondary national ambient air quality standards ( “ NAAQS ” or “ standards ” ) for particulate matter (PM) to add new annual and

24

- hour standards for PM 2.5 , particulate matter with a diameter of 2.5 microns or less

. 2 The

annual standards were set at a level of 15 micrograms per cubic meter (μ/m 3 ), as determined by

the 3

- year average of annual mean PM 2.5 concentrations. The 24

- hour standards were set at a

level of 65 μ/m 3 , as determined by the 3

- year average of the 98th percentile of 24

- hour

concentrations

.

In April 2005, we designated areas for the 1997 standar ds including designating the

South Coast as nonattainment for both the annual and 24

- hour PM 2.5 standards

. These

1 The South Coast includes Orange County, the southwestern two

- thirds of Los Angeles County, southwestern San Bernardino County, and western Riverside County (see 40 CFR 81.305.)

2 62 FR 38652 (July 18, 1997) and 40 CFR § 50.7. Prior to 1997, the EPA had ad dressed ambient particulate matter through other means, first by regulating “total suspended particles” and then, in 1987, by regulating PM 10 (particulate matter with a diameter of 10 microns or less). For more information on the particulate matter standar ds prior to 1997, see 78 FR 3086, 3090 (January 15, 2013). In addition to annual and 24

- hour PM 2.5 standards, the

current suite of PM standards includes a 24

- hour PM 10 standard of 150 ug/m 3 that was originally set in 1987 (52 FR 24663 (July 1, 1987)). The South Coast is designated as attainment for the PM 10 NAAQS. 40 CFR 81.305.TSD

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- Region 9 Page 6 designations b ecame effective on April 5, 2005. 3 In April 2007, the EPA issued an implementation rule to assist states with the development of SIP submissions to meet attainment planning requirements for the 1997 standards (the “2007 PM 2.5 Implementation Rule”) ( 72 FR 20583, ( April 25, 2007 ) ). The EPA premised the 2007 PM 2.5 Implementation Rule on its prior interpretation of the Act as allowing for implementation of the PM 2.5 standards solely pursuant to the general nonattainment area provisions of subpart 1, part D of title I of the CAA (“subpart 1”). Among other things, the 2007 PM 2.5 Implementation Rule included nationally applicable presumptions regarding the need to evaluate and potentially control emissions of certain PM 2.5

precursors. 4

In November 2007, Califo rnia submitted the South Coast 2007 AQMP to address the provisions of subpart 1 and the 2007 PM 2.5 I mplementation R ule for the 1997 PM 2.5 standards. 5

T hat plan inclu ded a demonstration that the South Coast would attain the 1997 PM 2.5 standards by April 5, 2015, 10 years after the nonattainment designation a nd the latest attainment date

allowed under subpart 1 ( CAA section 172(b) ) . In November 2011, we approved a ll but one

element of that p lan

. 6

On October 17, 2006, the EPA revised the 24

- hour PM 2.5 standard by lowering it to 35 μg/m 3 (“2006 PM 2.5 standard.”) and retained the annual standard at 15 μg/m 3

. 7 We designated

South Coast as nonattainment for the 2006 24

- hour standard effective December 1 4, 2009 (74 FR 58688 (November 13, 2009)). 8 In March 2012, the EPA issued a guidance document to aid states in preparing SIPs to meet attainment plan requirements for the 2006 24

- hour PM 2.5

3 70 FR 944 (January 5, 2005)

. CAA section 107(d) generally requires the EPA to designate areas as either nonattainment or attainment no later than 3 years after the promulgation of a new standard. The delay in designations following the promulgation of the first PM 2.5 standards in 199 7 was a result of extended litigation on those standards and Congressional action. For further information, see 70 FR 944, 945.

4 Specifically, in 40 CFR 51.1002(c), the EPA provided, among other things, that a state was “not required to address VOC [and a mmonia] as . . . PM 2.5 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 o f these pollutants “significantly contribute” to PM 2.5 concentrations in the nonattainment area (40 CFR 51.1002(c)(3), (4) and 72 FR 20586 at 20589

- 97 (April 25, 2007)).

5 The 2007 AQMP addressing the PM 2.5 NAAQS relied in part on the California Air Resour ces Board’s 2007 State Strategy (revised in 2011) for the additional mobile source measures needed to demonstrate attainment of the 1997

PM 2.5 standards in the South Coast. The State revised and updated the 2007 State Strategy in 2009 and both the 2007 AQM P and the 2007 State Strategy in 2011. For more information on the 2007 State Strategy and 2007 AQMP, see 76 FR 41562, 41563

- 5 (July 14, 2011). In these rulemaking actions, we refer to the 2007 AQMP and 2007 State Strategy and their revisions collectively as the “South Coast 2007 AQMP.”

6 76 FR 69928 (November 9, 2011). We disapproved the PM 2.5 contingency measures provisions in the 2007 AQMP. In November 2011 and April 2013 the State submitted revised contingency measure which we approved in October

2013 (78 FR 64402, October 29, 2013).

7 71 FR 61144 (October 17, 2006). On December 14, 2012, the EPA revised the annual PM 2.5 standard by lowering the level of primary (health

- based) annual PM 2.5 standard to 12.0 μg/m 3 and changing its form. No changes were

ma de to the 24

- hour PM 2.5 standards or the secondary (welfare

- based) annual PM 2.5 standards (78 FR 3086 (January 15, 2013)). On January 15, 2015, the EPA published nonattainment area designations for the 2012 PM 2.5 standard, including designation and classif ication of the South Coast Air Basin as moderate nonattainment for this NAAQS (80 FR 2206, 2215

- 16). Unless otherwise noted, all references to the “PM 2.5 standard” in this action are to the 2006

24

- hour PM 2.5 standard as codified in 40 CFR 50.13.

8 74 FR 58688 (November 13, 2009).TSD

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- Region 9 Page 7 NAAQS. 9 The 2012 guidance was based, in large part, on the require ments in the 2007 PM 2.5 Implementation Rule.

California had three years from the December 14 , 2009 effective date of the South Coast’s designation as nonattainment for the 2006 PM 2.5 NAAQS to submit a SIP for the South Coast that addressed the applicable requirements of the Act. 10 On December 7, 2012, the District adopted the Final 2012 Air Quality Management Plan , and on January 25, 2013, CARB adopted the plan as an element of the California SIP and submitted it to EPA on February 13, 2013. 11 On January 4 , 2013, several weeks after the District’s adoption of the 2012 PM 2.5 Plan, the U.S. Court of Appeals for th e D.C. Circuit issued its decision in a challeng e to EPA’s 2007 PM 2.5 I mplementation R ule

. See NRDC v. EPA , (706 F.3d 428 (D. C. Cir. 2013). In NRDC

, the court

held that the EPA had erred in implementing the 1997 PM 2.5 standard s solely pursuant to the general implementation requirements of subpart 1, without also considering the require ments specific to particulate matter nonattainment areas in subpa rt 4, part D of title I of the CAA (“subpart 4”). 12 The court reasoned that the plain meaning of the CAA requires implementation

of the 1997 PM 2.5 NAAQS under subpart 4 because PM 2.5 particles fall within the statutory

definition of PM 10 and are thus subjec t to the same statutory requirements as PM 10

. T he court

remanded the 2007 PM 2.5 Implementation R ule in its entirety, including the presumptions concerning VOC and ammonia in 40 CFR 51.1002, and instructed EPA “to repromulgate these rules pursuant to Subpart 4 consistent with this opinion.”

Consistent with the NRDC decision, o n June 2, 2014 (79 FR 31566), the EPA published a

final rule classif

ying all areas currently designated nonattainment for the 1997 and /or 2006 PM 2.5

s tandards as “Moderate” unde r 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

action s in both the proposed and final classification/deadline rule. See 78 FR 69806, 69809 (November 21, 2013 ) and 79 FR 31566, 31568 (June 2, 2014).

On February 6, 2015, the District adopted the Supplement to the 24

- Hour PM 2.5 State Implementation Plan (SIP) for the South Coast Air Basin (“2015 Supplement”) as a revision to

the 2012 PM 2.5 Plan. The District adopted the 2015 Supplement to address subpart 4 requirements for the 2006 PM 2.5 standard to the extent that these requirements are not adequately

address ed in the 2012 PM 2.5 Plan. CARB submitted the 2015 Supplement to EPA on March 4,

2015. The 2012 PM 2.5 Plan and the 2015 Supplement are the subject of today’s proposal. The

2015 Supplement includes information on the implementation of reasonably available c ontrol

measures for ammonia sources in the South Coast and the District’s demonstration that the 2012

PM 2.5 Plan and 2015 Supplement satisfy the requirements of subpart 4

. As a consequence of the

9 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 (PM 2.5 ) National Ambient Air Quality Standards (NAAQS)” (“2012 Guidance”)

Available at: http://epa.gov/ttn/naaqs/pm/pm25_guide.html

. 10 See CAA section 172(b) and 40 CFR § 51.1002(a).

11 This document will be r eferenced in this TSD an d the Federal Register proposal as the “2012 PM 2.5 Plan”, the

“South Coast 2012 PM 2.5 Plan”, or simply “the Plan”.

12 This NRDC decision also remanded the EPA’s 2008 final rule to implement the nonattainment New Source Review (NNSR) permitting requirements for the 1997 PM 2.5 standards (73 FR 28231 (May 16, 2008)) which, like

the 2007 PM 2.5 Implementation Rule, was premised on the requirements of subpart 1. We are not addressing requirements for NNSR programs in this proposal.TSD

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- Region 9 Page 8 NRDC decision, we are reviewing the South Coast 2012 PM 2.5 Plan and the 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) (the “General Preamble” ) and “State Implementation Plans for Serious PM

– 10 Nonattainment Areas, and Attainment D ate 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) (the “Addendum”). Th e General

Preamble at 13538 discusses the re lationship between 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 re lated to, the more specific [subpart 4] requirements.” S ome 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 conti nues to

govern. Other provisions of subpart 1 are subsumed or superseded by more specific requirements

in subpart 4 (e.g., certain provisions concerning attainment date s ).

Additionally, in a proposed rule published March 23, 2015 (80 FR 15340), the EPA

pro vided further interpretive guidance on the statutory SIP requirements that apply to areas designated nonattainment for the PM 2.5 standards (hereafter “Proposed PM 2.5 Implementation Rule”). We discuss these preliminary interpretations of the Act as appropriate in our evaluation

of the 2012 PM 2.5 plan and 2015 Supplement in section II of this TSD.

As part of this proposal, the EPA is proposing to determine that the South Coast cannot practicably attain the 2006 PM 2.5 standard by the Moderate area att ainment date of December 31, 2015, and to reclassify the 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, from Moderate to Serious n onattainment under subpart 4. Should EPA finalize this proposal to reclassify the South Coast area as a Serious area, the State will be required to adopt and submit a new plan addressing the Serious area requirements in subparts 1 and 4 of part D,

title 1 of the Act. We discuss these Serious area requirements in more detail in Section III below.TSD

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### B. PM 2.5 

### Air Quality Data for the South Coast Air Basin

The South Coast PM 2.5 nonattainment area is located in the southern part of California. It comprises port ions of Los Angeles County, all of Orange County, and the urbanized portions of San Bernardino and Riverside Counties. It is home to almost 18 million people and is one of the nation’s leading area for goods movement. See Figure IB

- 1 for a map of the South Coast nonattainment area and the major sources of air pollution in the nonattainment area. The local

air district with primary responsibility for developing a plan to attain the PM 2.5 NAAQS in this

area is the South Coast Air Quality Management District (“SCAQMD” or “District”). For a complete description of the PM 2.5 nonattainment area, please refer to 40 CFR part 81.305.

1. PM 2.5 Levels in the South Coast

Ambient PM 2.5 levels in the South Coast have declined considerably in the past 15 years

to levels just above the 2006 PM 2.5 NAAQS. For the 2011

- 2013 period, the 24

- hour PM 2.5 design value for the area, based on monitored readings at the Mira Loma monitor, is 36 ug/m 3

. 13

, 14
Figure IB

- 2 is a map of the current monitoring system in the South Coast.

Since co mprehensive monitoring began for PM 2.5 in the South Coast in the late 1990s, the area has seen a significant decline in ambient levels. All data have been certified by SCAQMD

for the 2012

- 2014 period. Data for all sites meets quarterly 75% completeness bu t four sites have at least one quarter with completeness less than 75% in the 2012

- 2014 period: Burbank, Pasadena, Ontario Fire Station, and San Bernardino.

13 AQS Design Value Report, AMP 480, September 28, 2015. “ 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).

14 Some data in the 2 nd , 3 rd and 4 th quarter of 2014 may have been impacted by a temporary lab closure and other issues at SCAQMD and are currently under review. Therefore, the 2012

- 2014 design value may be subject to change.TSD

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- 2

-

Figure IB

- 1. South Coast Nonattainment Area and Location of Major Sources of Air

PollutionTSD

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### Figure IB

- 2

– Ambient PM 2.5 

### Monitoring Locations In the South Coast Air BasinTSD

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- Region 9 Page 12 2. Chemical Composition of PM 2.5 in the South Coast

PM 2.5 in the air is a complex mixture of components. Common components include: nitrate (NO 3 ); sulfate (SO 4 ); ammonium; elemental carbon; a great variety of organic compounds; and inorganic material (including metals, dust, sea salt, and other trace elements)

g enerally referred to as “crustal” material, although it may contain material from other sources. “Primary” particles are emitted directly into the air as a solid or liquid particle (e.g., elemental carbon from diesel engines or fire activities, or condensa ble organic particles from gasoline engines). “Secondary” particles (e.g., nitrate and sulfate) form in the atmosphere as a result of chemical reactions between precursor pollutants such as NO
x , SO 2 , VOC, and ammonia. The

South Coast 2012 PM 2.5 Plan inclu des an updated ammonia inventory. Understanding the compounds that impact an area’s PM 2.5 problem is necessary in order to develop control strategies that are effective for attaining the 1997 PM 2.5 NAAQS.

PM 2.5 in the South Coast Air Basin is overwhelmingly formed as a secondary pollutant. (South Coast 2007 AQMP, page ES

- 9). Therefore, the South Coast 2007 AQMP relies on reducing precursors to PM 2.5 and some directly

- emitted PM 2.5 rather than fugitive dust. In general, the organic carbon (OC) m ass accounts for approximately 30 percent of the total mass at each station. Ammonium, sulfate and nitrates account for an approximate 45 percent of the total

mass at each monitoring location. The Rubidoux and Fontana monitors are the most heavily impacted by nitrates. Sulfate is highest in the near coastal or ports of Los Angeles/Long Beach areas, particularly Wilmington and Long Beach. Elemental carbon (EC) and metals measurements were highest at Wilmington, accounting for almost 24 percent of the mass wh en combined. All sites observed measurable concentrations of sodium and chloride ions reflecting the influence of the marine air as it is transported inland. Figure IB

- 3 shows the annual

distribution of PM 2.5 species in the South Coast PM 2.5 nonattainment area

.

Figure IB

- 3: MATES

- III 2005 Annual Distribution of PM 2.5 Species (μg/m3) 15

15 South Coast 2007 AQMP, Appendix V, p. V

- 2

- 4.TSD

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- Region 9 Page 13 More recent data collected for the Multiple Air Toxics Exposure Study IV (MATES IV) is presented below. To characterize the ambient level of pollutants in the South Coast Air Basin,

PM 2.5 , PM 10 and Total Suspended Particles (TSP) samples were collected once every six days at 10 monitoring stations from July, 2012 to June, 2013.

Figure IB

- 4 below illustrates the chemical closure of PM 2.5 . Overall, OM is the most

dominant cat egory, contributing an average of 44.2 ± 1.0% to the reconstructed mass. The levels of OM are relatively higher in sites that are further from the coast, namely Pico Rivera (annual avg. = 6.53 μg/m 3 ), Burbank (annual avg. = 6.73 μg/m 3 ), Inland Valley San B ernardino (annual avg. = 6.77 μg/m 3 ) and Rubidoux (annual avg. = 6.47 μg/m 3 ), although their contributions to the reconstruction mass are similar with other sites. The group of inorganic ions (36.0 ± 1.5%) is another major source category, with 16.0, 11.2 and 8.7% attributable to nitrate, sulfate and ammonia, respectively. EC accounts for an average of 8.6% of the reconstructed mass, and higher fractions are found at Pico Rivera (9.5%) and West Long Beach (9.3%). In general, the

standard deviations of the site

- wide annual average contribution of EC, OM and inorganic ions are less than 10% of their corresponding averages, highlighting the relatively low spatial variation of the three major source categories in this Basin. Approximately 5.9% of the

reconstru cted mass is attributed to crustal materials, with higher fractions at West Long Beach (8.1%) and Inland Valley San Bernardino (7.8%). Sea salt accounts for 5.3% of the reconstructed mass. Higher fractions are observed at West Long Beach (6.8%) and North L ong Beach (7.2%), while the inland stations of Inland Valley San Bernardino and Rubidoux record lower fractions at 3.6% and 3.7%, respectively.

Figure IB

- 4: MATES

- IV Annual Average (July 2012

– June 2013) Chemical Composition

and Gravimetric Mass Concentrations in PM2.5 Species (μg /m3) 16

16 Multiple Air Tox ics Exposure Study IV (MATES IV), Final Report, May 2015, SCAQMD. Appendix X, The Spatial and Temporal Trends of PM2.5, PM10, and TSP Components in the South Coast Air Basin

.TSD

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- Region 9 Page 14 The Multiple Air Toxics Exposure Study IV (MATES IV) is a monitoring and evaluation study conducted in the South Coast Air Basin. The study is a follow up to previous air toxics studies in the Basin (MATES II, MATE S III) and is part of the SCAQMD Governing Board Environmental Justice Initiative. The measurements for MATES IV spanned July 1, 2012, to June 30, 2013. The measurements for the previous study, MATES III, spanned April 2004 to

March 2006. A network of 10 fixed sites was used to monitor toxic air contaminants once every six days for one year. The locations of the sites for MATES IV were generally the same as in the MATES III study to allow for comparisons over time. The one exception is the West Long

Beach site, which was about 0.8 mile northwest of the location used in MATES III.TSD

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### C. California SIP Submittals for the 2006 PM 2.5 

### NAAQS in the S outh Coast

We are proposing to act on the two submittal s that California has made to address applicable CAA planning requirements for the 2006 PM 2.5 NAAQS in the South Coast

.

1. SCA Q MD, Final 20 12 Air Quality Management Plan (December 7, 2012)

CARB submitted th e 2012 PM 2.5 Plan as a SIP revision on February 13 , 2013. See letter,

dated February 13 , 2013, James N. Goldstene, Executive Officer, California Air Resources Board, to Jared Blumenfeld, Regional Administrator, EPA Region 9, with enclosures. The Plan

was adopted on December 7 , 2012 by the South Coast Air Quality Management District (S CAQM D or District) and on January 2 5 , 2013 by CARB

. See SCAQM D Governing Boar d

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 A QMP, to be referred to after adoption as the Final 2012 AQMP, and to be submitted into the California State Implementation Plan,” December 7 , 2012 and CARB Reso lution 13

- 3

, “ South Coast Air Basin

2012 PM 2.5 and Ozone State Implementation Plan s
, ” January 25 , 2013

. This document will be

r eferenced in this TSD and the Federal Register proposal as the “ 2012 PM 2.5 Plan ” , the “ South

Coast 2012 PM 2.5 Plan

, ” or simply “ the Plan

. ”

2. SCAQMD, Draft Supplement to the 24

- Hour PM 2.5 State Implementation Plan for the South Coast Air Basin, January 2015

CARB submitted the 2015 Supplement as a SIP revision on March 4 , 2015. See letter,

dated March 4 , 2015, Richard D. Corey , Executive Officer, California Air Resources Board, to Jared Blumenfeld, Regional Administrator, EPA Region 9, with enclosures. The 2015 Supplement was adopted on February 6 , 2015 by the South Coast Air Quality Management District (SCAQM D or District) and on February 19 , 2015 by CARB

. See SCAQMD Governing

Board Resolution 15

- 3 “A Resolution of the South Coast Air Quality Management District (SCAQMD) Governing Board approving the Supplement to the 24

- Hour PM2.5 State Implementation Plan (SIP) for the South Coast Air Basin, and S ubmitt al into the SIP ,” February

6 , 2015 and CARB Resolution 15

- 2

, “ Minor Revision to the South Coast Air Basin 2012 PM 2.5 State Implementation Plan ” February 19 , 2015. This document will be r eferenced in this TSD

and the Federal Register proposal as the “2015 Supplement” or “Supplement

. ”TSD

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### D

. Public Notice and Hearing Requirements for and Completeness of SIP

Submittal s

1. Public Notice and Hearing Requirements for SIP Submittals

CAA sections 1 10(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. T o meet this requirement , every SIP submittal must include evidence that adequate public notice was given and that an opportunity to request 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 heari ng prior to adoption and submittal of the 20 12 PM 2.5 Plan and 2015 Supplement

. T he District conducted public workshops, provided public comment periods, and held a public hearing prior to the adoption of the Plan on December 7 , 2012

. See S C AQM D Governing Board Resolution

, page 3

. CARB also provide d the required public notice and opportunity for public comment prior to its January 25 , 2013 public hearing on the Plan. See

Notice of Pub ic Meeting to Consider Approval of the South Coast Air Basin 2012 PM 2.5 an d

Ozone State Implementation Plan s
, December 21 , 2012.

For the 2015 Supplement, t he District made the Supplement available for public review

and comment on December 19 , 201 4

, more than 30 days in advance of the February 6, 2015 Board hearing. See S C AQM D Governing Board Resolution 15

- 3 , page 2

. CARB also provided the required public notice and opportunity for public comment prior to its February 19 , 2015 public hearing on the Supplement

. See Notice of Public Meeting to Consider a Minor Revision to

the Sout h Coast 2012 PM 2.5 State Implementation Plan,” February 9 , 2015.

The SIP submittals include proof of publication of notices for these public hearings. We find, therefore, that the 2012 PM 2.5 Plan and 2015 Supplement meet the procedural requirements

for public notice and hearing in CAA sections 110(a) and 110(l).

2. Completeness Determination s on SIP Submittals

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 t hat any plan that we have not affirmatively determined to be complete or incomplete will become complete by operation of

law six months after the da te of submittal

. A completeness review allows us to determine if the submittal includes all the necessary it ems and information we need to evaluate and act on it for substantive compliance with applicable requirements

. We make completeness determinations using criteria we have established in

40 CFR part 51, Appendix V

. These criteria fall into two categories: ad ministrative information and technical support information

. The administrative information provides documentation that

the state has followed basic administrative procedures during the SIP adoption process and thus we have a legally

- adopted SIP revision before us

. The technical support information provides us the information we need to determine the impact of the proposed revision on attainment and maintenance of the air quality standards.

We notify a state of our completeness determination by letter unle ss the submittal bec a me complete by operation of law

. A finding of completeness does not approve the submittal as partTSD

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S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 17 of the SIP nor does it indicate that the submittal is approvable

. It does start the 12

- month clock

we have to act on the SIP submittal un der CAA section 110(k)(2).

CARB’s February 1 3, 2013 submittal of the 20 12 PM 2.5 Plan became complete by operation of law on August 1 3, 2013

. The 2015 Supplement became complete by operation of law on September 4, 2015 . See Table I

- 1 below.TSD

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EPA

- Region 9 Page 18

Table I

- 1

. Completeness Evaluation for the South Coast 2012 PM 2.5 Plan and the 201 5 Supplement

Administrative Materials (per Appendix V, Section 2.1)

(a) Submittal letter from Governor/designee Y 2012 PM 2.5 Plan : Letter, James N. Goldstene, Executive Officer, California Air Resources Board, to Jared Blumenfeld, Regional Admi nistrator, EPA Region 9, February 13 , 2013. 2015 Supplement : Letter, Richard Corey , Executive Officer, California Air Resources Board, to Jared Blumenfeld, Regional Admi nistrator, EPA Region 9, March 4 , 2015

. CARB is the governor’s designee for the purposes of SIP submittals.

(b) Evidence of adoption Y 2012 PM 2.5 Plan : SCAQM D 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

CARB Resolution 13

- 3

, South Coast PM 2.5 and Ozone State Implementation Plan s , January

25 , 2013.

2015 Supplement : SCAQM D Governing Board Resolution 15

- 3, “ A Resolution of the South Coast Air Quality Management District (AQMD or District) Governing Board approving the Supplement to the 24

- hour PM 2.5 State Implementation Plan (SIP) for the South Coast Air Basin and Submittal into the SIP,” February 6, 2015.

CARB Resolution 15

- 2: “ Minor Revision to the South Coast Air Basin 2012 PM 2.5 State Implementation Plan ” February 19, 2015

. (c) State/District legal authority to adopt Y District: California H&SC 40600(b)

CARB: California H&SC 41650(a)

(d1) Copy of actual rule/plan Y 2012 PM 2.5 Plan : S C AQM D

, 2012 PM 2.5 Plan (main volume plus 10 Appendices), adopted

December 7 , 2012 and CARB “Staff Report on Proposed Revision s to the PM 2.5 and Ozone State Implementation Plan s for the South Coast Air Basin ,” Release Date: January 11, 20 13.

2015 Supplement : “Draft Supplement to the 24

- Hour PM 2.5 State Implementation Plan for the South Coast Air Basin,” January 2015.

(d2) Rule changes indicated by underline/cross

out N/A No previous version of this SIP has been adopted or submitted.

(e) Proof that action met procedural requirements Y See items (f) and (g) below.TSD

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EPA

- Region 9 Page 19

Table I

- 1

. Completeness Evaluation for the South Coast 2012 PM 2.5 Plan and the 201 5 Supplement

(f) Copy of public notice Y 2012 PM 2.5 Plan : District: Proofs of Publication of S C A QM D’s notice s of public hearing

, dated July 27, 2012, October 4, 2012, and November 7

, 2012.

CARB: Notice of Pub l ic Meeting to Consider Approv al of the South Coast Air Basin 2012

PM 2.5 and Ozone State Implementation Plan s
, ” December 21 , 2012.

2015 Supplement : District: Proofs of Publication of S C A QM D’s notice s of public hearing

, dated December 19, 2014.

CARB : Notice of Public Meeting to Consider a Minor Revision to the South Coast 2012

PM 2.5 State Implementation Plan,” February 9, 2015.

(g) Certification that hearing fulfilled public

notice Y 2012 PM 2.5 Plan : See 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 20 12 AQMP, to be referred to after adoption as the Final 2012 AQMP, and to be submitted into the California State Implementation Plan. ,” December 20, 2012, p. 4.

CARB Resolution 13

- 3

, South Coast Air Basin 2012 PM 2.5 and Ozone State Implementation

Plan s
, January 24, 2013, p. 6.

2015 Supplement :

(h) Public comments & agency response Y 2012 PM 2.5 Plan : S outh Coast 2012 PM 2.5 Plan , Response to Comments and copies of written comments received by CARB on the South Coast 2012 PM 2.5 Plan

. 2015 Supplement : Minutes from SCAQMD Board M eeting on Feb ruary 6 , 2015, included in SIP submittal package from CARB to EPA, dated March 4 , 2015

.

Technical Support (per Appendix V, Section 2.2)

(a) Regulated pollutants identified Y 2012 PM 2.5 Plan : Chapter s 4 and 5 and Appendix V, and

2015 Supplement : Attachments D and E

(b) Affected sources & attainment status

identified Y 2012 PM 2.5 Plan : Chapter 1

2015 Supplement : Main body of Supplement

(c) Rule/plan emissions impact Y 2012 PM 2.5 Plan : Chapters 4, 5 and Appendix III

2015 Supplement : Attachments A and FTSD

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- Region 9 Page 20

Table I

- 1

. Completeness Evaluation for the South Coast 2012 PM 2.5 Plan and the 201 5 Supplement

(d) Attainment, PSD & other required

demonstration Y 2012 PM 2.5 Plan , Chapter 5 and Appendix V , and Supplement, Attachment A

2015 Supplement : Attachments A and D

(e) Modeling support as appropriate Y 2012 PM 2.5 Plan : Chapter 5 and Appendi x V

2015 Supplement : Attachment A

(f) Reliance on continuous emission reductions Y 2012 PM 2.5 Plan : Chapter 4 and Appendix III

2015 Supplement : Attachment F

(g) Evidence of limits & other needed requirements Y 2012 PM 2.5 Plan : Chapter 4 and Appendices IV

- A, VI, IV

- C

2015 Supplement : Attachment D

(i) Justification for deviation from EPA policy N/A

OVERALL COMPLETENESS Submittal s are complete per 40 CFR part 51, Appendix V

## II. Evaluation of the South Coast 20 12 PM 2.5 

## P lan and 2015 SupplementTSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 22 A. Emission s I nventor ies

1. Requirements for Emissions I nvento ries

In addition to the requirements of subpart 4, SIP s for M oderate PM 2.5 nonattainment areas

must also meet the general provisions applicable to all nonattainment areas in subpart 1 of part
D, to the extent that these provisions are not superseded by more specific requirements in subpart 4. Among these subpart 1 provisions is the requirement in CAA section 172(c)(3) that a state
submit a SIP revision that includes a “comprehensive, ac curate, current inventory of actual emissions from all sources of the relevant pollutant or pollutants in [the] area.. .”

B y requiring an accounting of actual emissions from all sources of the relevant pollutants

in the area

, CAA section 172(c)(3) provides for the “base year” inventory to include all emissions that contribute to the formation of a particular NAAQS pollutant. F or the 2006 24

- hour PM 2.5 NAAQS , this would include pr imary PM 2.5 (also referred to as direct PM 2.5 ) as well

as the main chemical precursors to the formation of secondary PM 2.5 : NO
x , SO 2 , volatile organic compounds (VOC), and ammonia (NH 3 )

. Primary PM 2.5 includes condensable and filterable particulate matter (40 CFR § 51.50 “Particulate Matter”).

The EPA has issued the “Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations,” EPA

– 454/R

– 05

– 00 1 , November 2005 ( EI Guidance) 17 t o assist States in developing the required inventories

.
The emissions inventor y required under section 172(c)(3) is a SI P provision that must be approved by the EPA under CAA section 110(k) and is therefore subject to public hearing requirements pursuant to section s 110(a) (1),(a) (2)

, and (l)

. 18 A s tate should include in its SIP

submittal documentation explaining how the emissions data were calculated (EI Guidance, p.

37 )

. In estimating mobile source emissions

, a state should use the latest emissions models and planning assumptions available at the time the SIP is d eveloped (EI Guidance, p. 16)

. California is required to use EMFAC2011 to estimate tailpipe and brake and tire w ear emissions of PM 2.5 , NO
x , SO 2 , and VOC from on

- road mobile sources ( 78 FR 14533 ( March 6, 2013 ) ). States are require d to use the EPA’s AP

– 42 road dust method for calculating re

- entrained road dust

emissions from paved roa ds (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 s tate should 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 (EI Guidance, p. 7). By “ baseline

inventories” (also referred to as “projected baseline inventories ” ) , we mean projected emissions

17 Available at www.epa.gov/ttn/chief/eidocs/eiguid/index.html ) or in the docket for this proposed rule. We note that this guidance was developed to address requirements for the initial implementation of the 1997 ozone and PM 2.5 NAAQS and therefore, certain elements (e.g., the selection of 2002 as the inventory base year) are no longer

relevant.

18 See Memorandum dated September 29, 1992, John Calcagni, Director, Air Quality Management Division, Office

of A ir Quality Planning and Standards, EPA and William Laxton, Director, Technical Support Division, Office of Air Quality Planning and Standards, EPA, to Air Division Directors, Region I

- X, “Public Hearing Requirements for

1990 Base

- Year Emissions Inventories for Ozone and Carbon Monoxide Nonattainment Areas.”TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 23 inventories for future years that account for, among other things, the ongoing effects of economic growth and adopted emissions control requirements

. The SIP submission should include documentation explaining how the emissions project ion s were calculated

.

2. Emissions Inventories in the 2012 PM 2.5 Plan and 2015 Supplement

The annual average planning inventories for direct PM 2.5 and all PM 2.5 precursors (NO
x , SO
x , VOC, and ammonia ) for the South Coast PM 2.5 nonattainment area together with

documentation for the inventories are found in Chapter 3 and Appendix III of the South Coast

20 12 PM 2.5 Plan and in Attachment A to the 2015 Supplement

. 19 Additional inventory documentation, specific to the air qu ality mode ling, is in Appendix V

. Annual average invento ries are provided for the 2008 base year and for future years 2014 and the PM 2.5 attainment year of 201 5

. (Additional years such as 2017, 2019, 2023 and 2030 are also provided,

but these inventories are largely for 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 facto rs used to project these baseline inventories are derived mainly from data

obtained from the Southern California Association of Governments (SCAG), the met ropolitan planning organization (MPO) for the Los Angeles area (2012 PM 2.5 Plan, page 3

- 1 ).

Each inventor y include s emissions from point, area, on

- road, 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, N O
x , SO
x or PM report annual emissions to the District.

Point source emissions for the 2008 base year emission s inventory we re based on emissions reported from the SCAQMD’s Annual Emissions Reporting Program. 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. 20

Emissions inventorie s are constantly being revised a n d improved. Between the finalization of the South Coast 2007 AQMP and the development of the 2012 PM 2.5 Plan , the District added new area source categories such as liquefied petroleum gas (LPG) transmission losses, storage tank and pipeline cleaning and degassing, an d architectural colorants to the

inventories in the 2012 PM 2.5 Plan

. Emissions estimates for o ther source categories such as commercial and industrial internal combustion engines, landfills, composting waste, metal

coating operations, and livestock waste w ere adjusted based on new information available to the

District. See 2012 PM 2.5 Plan, pages 3

- 3 and 3

- 4, and Appendix III. Mobile Sources include on

-

19 Additional information, including a detailed breakdown of source categories, can be found on CARB’s website at http://www.arb.ca.gov/ei/emissiondata.htm.

20 AP

- 42 is EPA’s Compilation of Air Pollutant E mission Factors , and has been published since 1972 as the primary compilation 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 indu stry 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.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 24 road and off

- road (also called nonroad) sources. The on

- road mobile inventories use

EMFAC2011 for estimatin g motor vehicle emissions ( 2012 PM 2.5 Plan, p. 3

- 1 )

. 21

Since EMFAC2011 was released in 2011, CARB has adopted additional regulations to control air pollution from mobile sources . For the 2012 PM 2.5 Plan, the State adjusted

EMFAC2011 emissions estimates for the advanced clean cars program , reformulated gasoline

rules , and the Smog Check program to reflect this new information ( 2012 PM 2.5 Plan, p. 3

- 5 )

. Re

entrained paved road dust emissions were calc ulated using EPA’s AP

- 42 road dust methodology ( 2012 PM 2.5 Plan, Appendix III, p. III

- 1

- 13 and 2015 Supplement, Attachment B )

. SCAG, t he MPO for the Los Angeles area, provided transportation activity data from the adopted 2012 Regional Transportation Plan (RTP ). CARB’s EMFAC2011 was updated to reflect the most recent vehicle population, activity, and emissions data from the California Department of Motor Vehicles as well as rules adopted since EMFAC2007 including on

- road diesel f leet rules, clean

car standa rds, the low carbon fuel standard, and CARB’s Truck and Bus Rule.

Off

- road emissions such as c onstruction, mining, gardening and agricultural equipment emissions were calculated using CARB’s 2011 In

- Use Off

- road Fleet Inventory Model. The off

road equipme nt population was adjusted due to the 200 7

- 20 09 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 adjus tments 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 reduced economic activity. The District estimated aircraft emissions. Future emissions forecasts are based largely on growth forecasts (demographic a nd economic information) from SCAG. See 2012 PM 2.5 Plan, Appendix III, p. III

- 1

- 16 through II

- 1

- 23 and III

- 2

- 5

. A summary of the Plan’s 2008 base year inventory and the 2014 projected in ventory is provided in Table A

- 1 below. For a more detailed discussion of the inventories, see the 2012

PM 2.5 Plan, Appendix III

.

3

. Evaluation and Proposed Action

The emissions inventories in the 2012 PM 2.5 Plan were made available to the public for comment and were subject to public hearing a t both the District and State levels. See S C A QM D

Gov erning Board Resolution 12

- 19 , p. 3 and CARB Resolution 13

- 3 , p. 4

.
The inventories in the South Coast PM 2.5 SIP are based on the most current and accurate

information available to the State and District at the time the Plan and its inventories were being developed in 2011 and 2012

, including the latest EPA

- approved version of California’s mobile

source emission s model, EMFAC20 11 and the EPA’s most recent AP

- 42 methodology for paved

road dust. The inventories comprehensively address all source categories in the South Coast and were developed consistent with EPA’s i nventory guidance. For these reasons, we are prop osing to approve the 200 8 base year emissions inventor y in the 2012 PM 2.5 Plan as meeting the requirements of CAA section 172(c)(3). We also propose to find that the baseline inventories in

21 EMFAC2011 was approved for use in SIPs and conformity on March 6, 2013 (se e 78 FR 14533).TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 25 the Plan provide an adequate basis for the reasonably available control measure (RACM)

, reasonable further progress (RFP) and attainment demonstrations in the 2012 PM 2.5 Plan

.

Table A

- 1

. Summary of Emissions for the South Coast PM 2.5 Nonattainment Area

( annual average in tons per day )

200 8 2014

Direct PM 2.5

Stationary and Area Sources 48 50

On

- Road Mobile Sources 19 12

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

Source: South Coast 20 12 PM 2.5 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.TSD for the Proposed Action

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- Region 9 Page 26 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.

Air quality modeling is used to establish attainment emissions targets, the combination of

emissions of PM 2.5 and PM 2.5 precursors that the area can accommodate and still attain the standard, and to assess whether the proposed control strat egy 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 accept able, future year changes to the emissions inventory are simulated with the model to determine the relationship between emissions reductions and changes in ambient air quality. To project future design values, the model response to emission reductions, in the form of Relative Response Factors (RRFs), is applied to monitored design values from the base year.

For demonstrating attainment, the EPA’s recommendations for model input preparation, model performance evaluation, use of the model output for the attai nment 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

, PM 2.5 , and Regional Haze , EPA

454/B

- 07

- 002, April 2007 (“Modeling Guidance”), as amended by “Update to the 24 Hour PM 2.5 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”). 22 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 considering evidence other than the main air qual ity 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 a n 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.

22 T h e E P A m od el i n g g u i d a n ce is a v aila b le o n E P A ’ s S C R AM w eb s ite, w eb p a g e: h tt p :/ / ww w .e p a

. g o v / s c r a m 001 / g u i d a n c e_ s i p

. h t m ; d ire c t li nk s : h tt p : // ww w .e p a

. g ov / s c r a m 0 01 / gu i d a n c e / g u i d e / f

i n a l

- 03

- p m

- r h

- g u i d a n c e

. pd f a n d

h t t p :/ / ww w .e p a

. g o v / t t n / s c r a m

/ g u i d a n c e / g u i d e/U pd ate

_ t o_ t h e _2 4

- h o u r_ P M 2 5_ M o d ele d

_ A ttai n m e n t

_ T est. pd f.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 27 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 strate gy) 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 proof will generally be lower for an impracticability demonstration compared to an attainment demonstration.

2. Air Quality Modeling in the 2012 PM 2.5 Plan and 2015 Supplement

The 2012 PM 2.5 Plan’s attainment demonstration used photochemical modeling with the Community Multiscale Air Quality (CMAQ) model, with routinely available meteorological and air quality data as input. The Plan discusses air quality modeling in Chapter 5, “Future Air Qu ality” and in detail in Appendix V, Modeling and Attainment Demonstrations.

In its letter dated July 28, 2015, the SCAQMD requested that EPA reclassify the South

Coast Air Basin as Serious nonattainment for the 24

- hour PM 2.5 NAAQS based on monitoring data indicating that attainment is not practicable by the Moderate area attainment date, which is December 31, 2015. SCAQMD staff also requested that EPA treat the 2012 PM 2.5 Plan and 2015 Supplement, 23 together with the air quality data provided in the let ter, as a demonstration that the area cannot practicably attain by the Moderate area attainment date.

The data provided in the July 28, 2015 letter indicates that the Mira Loma air quality monitoring station exceeds the 24

- hour PM 2.5 NAAQS, and prelimin ary ambient 24

- hour PM 2.5 measurements at that station for the first quarter of 2015 indicate that the Basin will not attain the NAAQS by the moderate area deadline of 2015. The letter attributes the inability to attain the NAAQS largely to the lack of ra iny days in January and February of 2014 and 2015, which experienced 33 percent of the average rainfall. The District also discussed the effect of the drought on air quality in the 2015 Supplement. 24

Based on the request from the SCAQMD, the modeled atta inment 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 an impracticability demonstration.

a. Conceptual Description

23 Draft Supplement to the 24

- Hour PM2.5 State Implementation Plan for the South Coast Air Basin, January 2015.

24 Ibid.TSD for the Proposed Action

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- Region 9 Page 28 A conceptual descriptio n is a qualitative way of characterizing the nature of an area’s nonattainment problem. It can be helpful for developing a modeling protocol and in identifying potential stakeholders. It can also influence the choice of air quality model, modeling domain, grid cell size, priorities for quality assuring and refining emissions estimates, and the choice of initial diagnostic tests to identify potentially effective control strategies. In general, a conceptual description is useful for helping a state identify p riorities and allocate resources in performing a modeled attainment demonstration.

The Modeling Guidance lists 13 elements that should be addressed in the conceptual description at pp. 128

- 130. These are:

1. nature of nonattainment problem (e.g., local versus regional)

2. relative importance of primary and secondary components of PM 2.5

3. most prevalent components of measured PM 2.5

4. components of measurements versus emissions

5. areas with large gradients

6. indications of limiting precursor for secondary formation

7. monitored violations at locations subject to mesoscale wind patterns (e.g., at a coastline)
differing from the general wind flow

8. recent changes in PM emissions in or near the nonattainment area

9. trends in design values or other air quality indicators that have accompanied emissions changes

10. spatial patterns to trends in design values or other air quality indicators

11. past modeling results

12. distinctive meteorological measurements coinciding with e xceedances

13. correlations of PM or components with each other and other pollutantsTSD for the Proposed Action

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- Region 9 Page 29 The Plan’s conceptual model is discussed in 2. Chemical Composition of PM 2.5 in the
South Coast, above. The EPA f inds t h a t t he c on ce ptual d e s c ription of the P M 2

. 5 probl e m i n

pro v ided in the P lan is a d e qu a te l y do c u ment e d, c onvinci n g
, a nd fo r ms an a d e q u a te b a sis f or the d e v e lo p ment of the mod e l i ng proto c ol a n d the a ir qu a l i t y a n a l y sis wo r k i t s e lf.

b. Modeling Protocol

A modeling protocol should detail and formalize the procedures for conducting all phases of the modeling study, such as describing the background and objectives for the study, creating a schedule and organizational structure for the study, developing the input data, conducting model performance evaluations, interpreting modeling results, describing procedures for using the model to demonstrate whether proposed strategies are sufficient to attain the NAAQS, and producing documentation to be submitted for EPA Regional Office review and approval. The Modeling G uidance at pp. 133

- 134 describes a minimum list of topics to be addressed in the modeling protocol:

1. Overview of Modeling/Analysis Project

a. Management structure
b. Technical committees or other communication procedures to be used

c. Particip ating organizations
d. Schedule for completion of attainment demonstration
e. Description of the conceptual model for the nonattainment area (or Class I area(s))

2. Model and Modeling Inputs
f. Rationale for the selection of air quality, meteorologi cal, and emissions models
g. Modeling domain

h. Horizontal and vertical resolution
i. Specification of initial and boundary conditions
j. Episode selection
k. Description of meteorological model setup
l. Development of emissions inputs
m. Geograph ic area identified for application of the attainment test(s)
n. Methods used to quality

- assure emissions, meteorological, and other model inputs

3. Model Performance Evaluation
o. Description of the ambient air quality data base

p. Description of the evaluation procedures
q. Identification of possible diagnostic testing that could be used to improve model performanceTSD for the Proposed Action

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- Region 9 Page 30 4. Supplemental Analyses

r. Description of the additional analyses to be completed to corroborate the model

attainment test

s. Outline of the plans for conducting a weight of evidence determination, should it be

necessary

5. Procedural Requirements

t. Identification of how modeling and other analyses will be archived and documented
u. Identification of specific deliverables t o EPA Regional Office

2012 PM 2.5 Plan Modeling Protocol 25

Table V

- 2

- 1 in Appendix V of the 2012 PM 2.5 Plan provides a side

- by

- side comparison of

the 2012 PM 2.5 Plan and 2007 AQMP modeling protocols. The differences between the modeling structure focus on a limited number of areas. In general, changes to emissions inventories, future year simulations and episode selection evaluation are specific to the base year selected and the level of the non

- attainment designation. As such, these changes are expected to occur as part of each modeling update. The more substantive changes to the 2012

PM 2.5 Plan protocol reflect the use of CMAQ as the primary modeling platform, Weather Research and Forecasting as the meteorological modeling platform, and the changes to the size of the modeling region, vertical structure and grid size. For this set of modeling analyses, CMAQ was selected as the primary dispersion modeling platform. One element in the decision to use CMAQ as the primary modeling platform was the fact that it w as a publicly

- available model with numerous computational features and ongoing support in the modeling community. When evaluated for possible use in the attainment demonstration, both CMAQ and CAMx exhibited similar model performance in predicting 24

- hour and annual PM 2.5 levels. CMAQ however tended to predict monitored ozone concentrations with higher accuracy than CAMx. The migration to WRF from MM5 (a mesoscale meteorological model) as the primary meteorology modeling tool follows its ongoing use as the mainstay in weather forecasting by the National Weather Service, and its continuing development and support by the National Oceanic and Atmospheric Administration and U.S. EPA.

The P roto c ol cov e rs the top i c s listed above, a l t ho u g h s o me m e teo r ol o g ic a l and a i r qu a l i t y model a n a l y s e s lack detail. EPA finds the Protocol to be an adequate b a sis for the P l a n’s

mod e l i ng w o rk.

c. Air Quality Model Selection

A model should meet several general criteria for it to be considered in the development of

an attainment d emonstration (Modeling Guidance, p. 136). These general criteria are consistent with requirements in 40 CFR § 51.112 and 40 CFR part 51, Appendix W, EPA’s Guideline on

25 2012 PM 2.5 Plan, Appendix V, Table V

- 2

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- Region 9 Page 31 Air Quality Models . The EPA does not recommend a specific model for use in PM 2.5 attainm ent demonstrations. At present, no single model has been extensively tested and shown to be clearly superior to its alternatives. Thus, 40 CFR Part 51 Appendix W does not identify a preferred model for use in attainment demonstrations for the PM 2.5 standards. Based on the language in Appendix W, models used for these purposes should meet requirements in the Appendix for alternative models.

States should use a non

- proprietary model, that is, a model whose source code is available for free (or for a r easonable cost) and whose code can be revised by the state in order to perform diagnostic analyses and/or to improve the model’s ability to describe observations in a credible manner. A model should meet several additional prerequisites before being used t o support an attainment demonstration. It should be:

1. revised in response to a scientific peer review,

2. appropriate for the specific application on a theoretical basis,

3. used with a data base which is adequate to support its application,

4. shown to have performed well in past ozone or PM modeling applications (or if it is the first application, then the state should note why it believes the new model is expected to perform sufficiently); and

5. applied consistently with a protocol on methods and procedures.

In the 2012 PM 2.5 Plan, CMAQ was selected as the primary dispersion modeling platform based on the CMAQ is publicly

- available model with numerous computational features and ongoing support in the modeling community. In addition, when evaluated for possib le use in the attainment demonstration, both CMAQ and CAMx exhibited similar model performance in predicting 24

- hour and annual PM 2.5 levels. CMAQ however tended to predict monitored ozone concentrations with higher accuracy than CAMx.

The EPA finds that the c hoice of t h e CMAQ model is a d e qu a te l y jus t ifi e d b e c a use the

r a t i on a le pro v ided in the plan meets the 5 requirements listed above. The database, past performance, and protocol are discussed in more detail in the plan and below. T he EP A

sponsor e d CM A Q is e x pl i c i t l y mentioned in t he Mod e l i ng Guid a n c e (p. 138) a s b e ing a suitable mo d e l. The ability of CMAQ to predict monitored ozone concentrations with higher accuracy than CAMx is important because it provides a consistent platform for modeling ozone and particulate matter in the South Coast Air Basin.

d. Episode Selection

The Mo deling Guidance recommends one of two possible approaches in modeling for the

24

- hour PM 2.5 NAAQS (Modeling Guidance, p. 147):TSD for the Proposed Action

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- Region 9 Page 32 1) Model every day for a full year (or multiple years). This is recommended for both dispersion modeling of primary PM 2.5 component s and photochemical modeling of secondary and primary components. Many areas that violate the 24

- hour PM 2.5 NAAQS

will also violate the annual PM 2.5 NAAQS. Therefore, full year modeling may already exist or be planned for the annual NAAQS attainment test. Modeling at least a full year will also help ensure that a sufficient number of days is included in the relative reduction factor (RRF) calculations. 2) Model episodes when high PM 2.5 concentrations occur. Similar to modeling for the ozone NAAQS, episodes should be selected where PM 2.5 concentrations are greater than the NAAQS (in this case, the 2006 standard of 35 μg/m 3 ) and are close to the baseline design value (the design value in t he planning baseline year). Also similar to ozone modeling, data analyses can be completed to help select a variety of meteorological episodes which lead to high PM 2.5 concentrations. In some cases, very limited conditions may lead to high 24

- hour

average PM 2.5 concentrations, and in other cases there may be a wide variety of conditions. The specific situation in each nonattainment area will determine the number of episodes and the time periods which need to be modeled. For example, if exceedance

- level PM 2. 5 concentrations in an area only occur in the winter, then a limited number of winter days can be modeled. In other areas, exceedance days may occur in all seasons. We also recommend that the modeling “focus on the high end of the distribution of days in e ach quarter, (e.g. the top 10% of PM 2.5 days) assuming that the high days are representative of days that violate the NAAQS.” (Modeling Guidance Update, p. B

- 1).

For modeling purposes, “base case” means the historical period that is simulated in the air quality modeling, including its meteorology, air quality, and emissions inventory. This period is chosen during the episode selection process, based on representati ve meteorology and air quality, and the availability of meteorological, air quality, and emission inventory data for input to the modeling. The term “baseline” refers to the starting point for controls are applied; it can be the same year as the base case, or it could be a period convenient for planning purposes, e.g. because of emission inventory availability. (CARB refers to this as the “reference year”.)

The modeling approach in the plan used the first approach of modeling every day for an entire year. CMAQ simulations were conducted for each day in 2008. The simulations included 8784 consecutive hours from which daily 24

- hour average PM2.5 concentrations (0000

- 2300 hours) were calculated. The EPA finds the modeling approach of modeling every day in 20 08 to be adequate.

e. Domain, Domain Size, and Spatial Resolution

i. Domain Size
The principal determinants of model domain size are the nature of the PM 2.5 problem and the scale of the emissions which impact the nonattainment area. Isolated nonattainment areas that are not affected by regional transport of PM and its precursors may be able to use a relatively small domain. Some areas of the western U.S. may fall into this category. The modeling domain should be designed so that all major upwind source are as that influence the downwind nonattainment area are included in the modeling domain. The influence of boundary conditions should be minimized to the extent possible (Modeling Guidance, p. 153).TSD for the Proposed Action

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- Region 9 Page 33 In domain size and spatial resolution is discussed in Chapt er 2 of Appendix V in the 2012

PM 2.5 Plan. The most significant changes to the modeling analyses in South Coast’s 2012 PM 2.5 Plan, compared with that defined in the 2007 PM 2.5 Plan, occur in the size of the domain, reduced grid size and increased vertical structure. First and foremost, both PM 2.5 and ozone will be simulated together using the same domain specification. The size of the domain has been expanded 65 km further west to attempt to incorporate clean boundaries into the modeling region, and 40 km t o the south to include a greater percentage of northern Mexico emissions. 26
See Figure II

- B

- 1.

FIGURE II

- B

- 1. South Coast Modeling Domain 27 (Source: South Coast 2012 PM2.5 Plan, Appendix V, Figure V

- 2

- 2)

ii. Horizontal Resolution

The EPA recommends that states use grid cell sizes as large as 12 kilometers (km) for urban scale applications addressing secondary components of particulate matter. However, in addressing the primary components of PM 2.5

, in some cases, cells as small as 4 km (or possibly

smaller ) may be needed. Alternatively, large sources of primary PM can be modeled with a

26 2012 PM 2.5 Plan, Appendix V, p. V

- 2

- 2.

27 2012 PM 2.5 Plan, Appendix V, p. V

- 2

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- Region 9 Page 34 dispersion model or a combination of grid and dispersion models. For the regional outer nest of the domain, grid cells as large as 36 km may be used (Modeling Guidance, p. 157).
In the South Coast 2012 attainment plan modeling, the grid size has been reduced from 5 x 5 km to 4 x 4 km. The reduced grid size better enabled the merging of the statewide emissions inventory, which is set at the 4 km grid scale based on a Lambert Conformal projection. 28

Another clear benefit of the modification to the grid size was the smoother coupling of the meteorological modeling field development. 29 The WRF analyses are initialized from the

National Cen ters for Environmental Prediction (NCEP) model output at 36 km grid level, then scaled downward based on a 3:1 scaling ratio to a 12 km grid inner

- modeling domain covering most of California to set the regional meteorological boundary conditions for the 4 km grid modeling domain

iii. Vertical Layers

There is no specified minimum number of vertical layers needed in an attainment demonstration. The vertical resolution will vary depending on the application. Greater resolution allows more precise estimation of mixing heights and avoids unrealistic step

i ncreases in mixing; alignment with the layers in the meteorological model can affect accuracy; the lowest layer should generally be no more than 50 meters thick; resolution above the boundary layer can generally be coarser. Recent applications of one atmos phere models (with model tops at 100 millibars (mb)) have used anywhere from 12 to 21 vertical layers with 8

- 15 layers approximately within the boundary layer (below 2500 m) and 4

- 6 layers above the Planetary Boundary Layer (PBL) (Modeling Guidance p. 159)

.

Table II

- B

- 1 below indicates the vertical layers used in the 2012 PM 2.5 Plan.

Table II

- B

- 1

. 2012 PM2. 5 Plan Modeling Vertical Layer Structure 30

WRF

Layer

Index Mid

- Point

Height (m) CMAQ

Layer

Index Mid

- Point

Height (m)

28 2012 PM2. 5 Plan, Appendix V, p. V

- 2

- 5

29 2012 PM2.5 Plan, Appendix V, p. V

- 2

- 6

30 2012 PM 2.5 Plan, Appendix V, p. V

- 2

- 7, Table V

- 2

- 3

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- Region 9 Page 35

30 19268 15 19268

29 17355

28 15755

27 14337 14 14337

26 13028

25 11791

24 10598

23 9429

22 8271 13 8271

21 7118

20 5994

19 4992

18 4153

17 3449 12 3449

16 2858

15 2361

14 1944 11 1944

13 1595

12 1302

11 1057

10 851 10 851

9 681 9 681

8 538 8 538

7 418 7 418

6 318 6 318

5 235 5 235

4 165 4 165

3 107 3 107

2 59 2 59

1 18 1 18

The layer structure in the vertical domain for the modeling region has been increased to 15 layers from the previous the eight layers used in the CAMx PM 2.5 attainment demonstration

simulations. Table V

- 2

- 3 in Appendix V of the 2012 PM 2.5 Plan provides a definition of the 15 layer vertical structure used in the air quality simulations. Also listed is the corresponding 30 layer structure of the WRF modeling vertical domain that matches the CMAQ domain at the top height. Table II

- B

- 2 indicat es the coordinates of the modeling domain used in the 2012

PM 2.5 Plan.

TABLE II

- B

- 2. 31 Final 2012 PM2.5 Plan Modeling Domain

31 2012 PM 2.5 Plan, Appendix V, p. V

- 2

- 5, Table V

- 2

- 2

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- Region 9 Page 36 The EPA f

inds t he doma i n to be a d e qu a t e
, a nd c o n si s tent with E P A Mod e l i ng Guid a n ce

. T h e inner domain me e ts all of the Mod e l i ng Guid a n c e domain c h a ra c te r is t ics li s ted a bove f o r

sp a t i a l r e solu t ion and l a y e r thi c k n e ss.

f. Initial and Boundary Conditions

If there is no larger regional model application available, then we recommend that background boundary conditions be used to specify initial and boundary concentrations for the attainment demonstration modeling. However, concentration fields derived from a larger domain regional or global chemistry model (i.e., the nesting approach) is considered more credible than the assumption of static concentrations, since the pollutant concentration fields reflect simulated atmospheric chemical and physical processes driven by assimilated meteorological observations. Therefore, the EPA recommends using boundary conditions derived from a regional or global scale model, whenever possible. We also recommend using a ramp

- up period by beginning a simulation prior to the per iod of interest to diminish the importance of initial conditions. The recommended ramp

- up period is at least 5

- 10 days for PM 2.5 . Diagnostic testing which indicates a large impact on the model results from initial or boundary conditions may indicate that t he domain is not large enough or the ramp

- up period is too short. In either case, it should generally be assumed that initial and boundary conditions do not change in the future. The use of altered initial or boundary conditions in the future year should b e documented and justified (Guidance, p. 153).

As discussed in Chapter 4 of Appendix V of the 2012 PM 2.5 Plan, the initial concept for establishing boundary conditions for the regional modeling analyses focused on using global

chemical simulation model ou tput to define key species concentrations at the edge of the modeling domain. The Model for Ozone and Related Chemical Tracers (MOZART) was selected to provide the characterization. However, after evaluation, it was discontinued in favor of using a

U.S. EP A “clean boundary 32 approach that has been incorporated in previous attainment

demonstrations. 33 The boundary conditions are listed in Table II

- B

- 3. Boundary Profile

Concentrations , below.

32 Guidelin e For Regulatory Application of the Urban Airshed Model, USEPA, 1991

33 2012 PM 2.5 Plan, Appendix V, p. V

- 4

- 10.



### Projection L a m bert C o n f or m al

P r ojection Latitude of Origin 37 N Modeling D o m ain 156 x 102 x 18

Vertical L a y e r Struc t u r e Variable up to 50 h Pa ( m b )

Central Me r idian 120.5 W

Standard P arallel 30 N, 60 N

Horizontal Grid S i ze 4 k m x 4 k m Southwest Origin (

- 84 k m
, - 552 k m )TSD for the Proposed Action

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- Region 9 Page 37 This decision was discussed in greater detail in Chapters 1 and 3 of Appendix V of the

2012 PM 2.5 Plan. Lateral and vertical boundary conditions were designated using an “U.S. EPA clean boundary profile.” The analysis tested the use of MOZART (Model of Ozone and Related Chemical Tracers, [Horowitz, L.W., et. Al., 2003]), g lobal chemical simulation model output to specify the lateral and vertical boundary conditions used for the CMAQ modeling. Grid scale matching using MOZART at 60 x 60 km compared with the CMAQ 4 x 4 km grid introduced significant uncertainty to the boundar y concentration profiles and subsequent regional simulations. Background simulations including the MOZART boundary specification while excluding anthropogenic emissions depicted large variations in background concentrations.

Discussions conducted at the Sc ientific Technical Modeling Peer Review Advisory Group suggested that a finer scale MOZART output might dampen the variable impact to the regional air quality simulations. While this recommendation was acknowledged, the resources and time requirements need ed to generate new global modeling output were prohibitive. The final simulations reverted to the more stable clean boundary assumption.

Table II

- B

- 3. Boundary Profile Concentrations (ppb) 34

SAPRC99 Species (ppb) SAPRC99 Species (ppb)

HCHO 0.930 ARO1 0.210

CCHO 0.530 ARO2 0.070

RCHO 0.250 OLE1 0.180

0.020 OLE2 e

- 13

MEOH 0.100

ETOH 0.050 O3 40.0

ETHE 0.180 CO 200.

ALK1 2.500

ALK2 2.300 NO 0.100

ALK3 0.930 NO2 (surf) 2.000

ALK4 e

- 13 NO2 (aloft) 0.100

ALK5 e

- 13

The EPA finds the boundary conditions procedures adequate for this demonstration that attainment by the Moderate area attainment date is impracticable, although the basis for this selection was sparsely documented. EPA expects more complete documentation of boundary

condition evalu ation and selection for an attainment demonstration, given that the resource and time constraints needed to generate new global modeling output should be less.

Meteorological Model
i. Meteorological Model Selection

34 2012 PM 2.5 Plan, Appendix V, p. V

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- Region 9 Page 38 A description of the methods used to gen erate the meteorological fields should be included in the modeling protocol. In cases in which standard meteorological modeling (e.g. MM5, RAMS (Regional Atmospheric Modeling System) or WRF in a retrospective analysis model is not used, the EPA recommends that a detailed description of the technique that will be used to generate the three

- dimensional meteorological fields be shared with the appropriate EPA Regional Office prior to conducting the air quality modeling analysis (Modeling Guidance, p. 161).

Th e meteorological model selection is discussed in Chapter 3 of Appendix V of the 2012

PM 2.5 Plan. The Final 2012 AQMP regional modeling relied on WRF model applications for 2008. The migration to WRF was based on two factors: First, WRF is the state

- of

- th e

- art meteorological forecast model used by the NWS and scientific community. It is under continual review and benefits from updates to critical modeling parameters. In moving to a new meteorological model, several analyses were conducted to compare WRF a nd MM5 meteorological fields to confirm the portability of the CMAQ modeling system to the new

model.

The Plan describes the meteorological model, the comparison between WFR and MM5, the selection of the vertical stability parameterization, land use, and initial and boundary

conditions used in the 24

- hour PM2.5 attainment demonstration. Based on the model performance evaluation presented in the plan, the E P A f inds t h a t t he meteorological model

c hoice is a d e qu a te l y j ust i fi e d.

ii. Meteorological Model Domai n

Most attainment demonstrations will cover large areas and use nested grids. The outermost grid should capture all upwind areas that can reasonably be expected to influence

local concentrations of PM 2.5 . In terms of selecting an appropriate meteorological modeling domain, a state should extend the grid 3 to 6 cells beyond the domains of each air quality modeling grid to avoid boundary effects. For example, if 4 km grid cells are to be used in the fine portion of a nested regional air quality model, then the meteorological fields at this detail

would need to extend 12

- 24 km beyond the bounds of the 4 km grid used for air quality predictions. In terms of grid resolution, the EPA recommends that the dynamic meteorological models use the same grid resolution as desired for the air quality model applications. In some cases, however, this may not be feasible. One possible reason for modeling with meteorology using a different grid resolution is in the case of unacceptable model performance from the

m eteorological model at the desired grid resolution. In other instances, the need for finer resolution may be emissions

- driven more than meteorologically

- driven and the costs do not warrant the generation of additional resolution in the meteorological data. In these specific situations, it is recommended that the air quality model application use available results from meteorological models on the next coarser scale (i.e., 36 km for a desired 12 km estimate, 12 km for a desired 4 km estimate). The coarse gri d meteorological fields can be mapped to the more finely resolved air quality modeling domain.TSD for the Proposed Action

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- Region 9 Page 39 The Meteorological Model Domain is discussed in Chapter 3 of the plan. WRF simulations were conducted with three nested domains of which grid resolutions were 3 6, 12 and 4 km. The innermost domain has 163 by 115 grid points in abscissa and ordinate, respectively, which spans 652 km by 460 km in east

- west and north

- south directions, respectively. Geographically, the domain encompasses the greater Los Angeles and s uburban areas, its surrounding mountains, and seas off the coast of the Basin as shown in Figure II

- B

- 2, below. The relative locations and sizes of the three nested grids are shown as well.

Figure II

- B

- 2. Three nested modeling domains employed in the WRF simulations 35

iii. Physics Options

Most meteorological models have a suite of physics options that allows users to select how a given feature will be simulated. For example, there may be several options for specifying the planetary boundary layer scheme or the cumulus parameterization. In m any situations, the

35 2012 PM 2.5 Plan, Appendix V. p. V

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- Region 9 Page 40 optimal configuration cannot be determined without performing an initial series of sensitivity tests which consider various combinations of physics options over specific time periods and regions. While these tests may not ultimately con clude that any one configuration is clearly superior at all times and in all areas, it is recommended that these sensitivity tests be completed, as they should lead to a modeling analysis that is best

- suited for the domain and period being simulated. Typic ally, the model configuration which yields predictions that provide the best statistical match with observed data over the most cases (episodes, regions, etc.) is the one that should be chosen, although other more qualitative information can also be consid ered in choosing a model configuration. Additionally, model configurations should be designed to account for the pollutants and time periods that are of most interest. As an example, a wintertime PM simulation in the Midwest (with high measured nitrate con centrations) may need a meteorological model configuration that employs a land

- surface model that properly

handles snow

- covered fields and their effects on boundary layer humidities and temperatures.

The physics option selection process and sensitivity te sts are discussed in Chapter 3 of the plan. YSU was chosen as the planetary boundary layer (PBL) scheme for the current attainment demonstration. Three land surface models (LSM) were considered for WRF modeling: the five

- layer thermal diffusion scheme, an d the Noah and Pleim

- Xiu schemes. By comparison to the effect of using different PBL schemes, modifications to the LSM caused significant responses in near surface variables. First, wind was generally overpredicted during the daytime and under

- predicted d uring the nighttime. The difference between the two schemes was signified during the nocturnal stable period, which occurred in temperature predictions as well. As for wind, the Noah showed a better agreement with observations, while temperature prediction was worse. The 5

- layer slab model agreed better with the measurements, as evident in the warmer surface temperature fields and the convective boundary layer predicted to be deeper in the Noah scheme

The EPA f

inds t h a t t he met e orol o g ic a l do m a in and model physics options a re a c ce pt a ble

a n d c onsistent with EPA Mod e l i ng Guid a n ce

.

h. Meteorological Model Performance

The EPA recommends that states devote appropriate effort to the process of evaluating the meteorological inputs to the air quality model, as we believe good meteorological model performance will yield more confidence in the predictions from the air quality model. This evaluation should determine if the meteorological model output fields represent a reasonable approximation of the actual meteorolog y that occurred during the modeling period. This can be done via an operational evaluation (i.e., quantitative, statistical, and graphical comparisons). A second objective of the evaluation should be to identify and quantify the existing biases and

errors in the meteorological predictions in order to allow for a downstream assessment of how the air quality modeling results are affected by issues associated with the meteorological data. This evaluation can be done via a more phenomenological assessment (i.e. , generally qualitative comparisons of observed features versus their depiction in the model data) (Modeling Guidance, p. 163).TSD for the Proposed Action

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- Region 9 Page 41 Operational Evaluation (Modeling Guidance, p. 163): The operational evaluation results

should focus on the values and distribut ions of specific meteorological parameters as paired with and compared to observed data. The observation

- model matching should be paired as closely as possible in space and time. Typical statistical comparisons of the key meteorological parameters will inc lude: comparisons of the means, mean bias, mean normalized bias, mean absolute error, mean absolute normalized error, root mean square error (systematic and unsystematic), and an index of agreement. For modeling exercises over large domains and

entire seas ons or years, we recommend that the operational evaluation be broken down into individual segments such as geographic sub

- regions and/or months/seasons to allow for a more comprehensive assessment of the meteorological strengths and weaknesses.

Phenomenol ogical Evaluation (Modeling Guidance, p. 167): Within the conceptual description of a particular modeling exercise, EPA recommends that a state identify and qualitatively rank in importance the specific meteorological parameters that influence air quality. When evaluating meteorological models or any other source of meteorological data, the focus of the phenomenological evaluation should be on those specific meteorological phenomena that are thought to strongly affect air pollution formation and transport w ithin the scope of a specific analysis. It is expected that this event

- oriented evaluation will need to summarize model performance in terms of statistical metrics such as probability of detection and false alarm rate. As an example of a potential phenomen ological analysis, many regional air quality modeling exercises attempt to assess the effects of transport of emissions from one area to a downwind

area with an intent to establish source

- receptor relationships. For these types of modeling analyses, accura te transport wind trajectories are needed to properly establish these source

receptor linkages. In this type of model application, a useful event

- based meteorological evaluation would be to compare model

- derived trajectories versus those based on ambient data

to determine what error distance can be associated with the model fields.

The statistical performance evaluation is discussed in detail in Chapter 3 and Attachment

1: WRF METSTAT Model Graphical Performance Statistics of Appendix V of the 2012 PM 2.5 Plan. A set of statistical variables were generated using the METSTAT software to evaluate the WRF modeling performance quantitatively. The list of statistical parameters included bias, gross error and root mean square error and the Index of Agreement (IOA ). The IOA was calculated following the approach of Willmont (1981). This metric condenses all the differences between model estimates and observations within a given analysis region and for a given time period (hourly and daily) into one statistical quant ity.

Overall, the daily WRF simulation for 2008 provided representative meteorological

fields that well characterized the observed conditions. The EPA f inds t he met e o rolo g i c a l m od e l

p e r f o rm a n c e is a d e qu a t e.

i. Emissions Inventory
Air quality modeling requires emissions inputs for base case, baseline, and future modeling years. Preparation of emissions data for air quality models for the base and future years requires several steps. First, a state needs to compile base

- year inventor ies for its modelingTSD for the Proposed Action

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- Region 9 Page 42 region (e.g., the state and tribal areas in the modeling grid). For PM model applications, emissions inventories should include emissions of anthropogenic and biogenic VOC (speciated), NOx, carbon monoxide, SO2, NH 3 , PM 2.5 (speciated), and PM coarse (PMC). Second, modelers must collect ancillary data associated with the inventories, which describes the spatial, temporal, and chemical speciation information about the emissions inventory. Third, modelers use the ancillary data for emissio ns modeling. Emissions models spatially, temporally, chemically, and vertically allocate emissions inventories to the resolution needed by the air quality model. Fourth, modelers must collect data on growth rates and existing control programs for use in

pr ojecting the base year emissions inventories to the future year, and then use an emissions model to prepare that future year inventory data for input to the air quality model. Fifth,

emissions inventories that reflect the emissions reductions needed for at tainment will have to be prepared for air quality modeling.

Chapter 3 of Appendix V of the 2012 PM 2.5 Plan provides the baseline and controlled modeling emissions inventories used for modeling and alternative analyses. The CMAQ

simulations were based on the annual average inventory, with adjustments made for weekly and daily temperature variations. A brief characterization of the annual day emissions used for the modeling analysis follows is discussed. An extensive discussion of the overall emissions

inve ntory is summarized in Appendix III of the Final 2012 AQMP. The EPA f inds t he mode l ing

e m i ss i ons inv e nto r y pr e p a r a t i on p r o ce d u r e s w e re a d e qu a te.

j. Air Quality Model Performance

PM 2.5 consists of many components and is typically measured with a 24

- hour averaging time. The individual components of PM 2.5 should be evaluated individually. In fact, it is more important to evaluate the components of PM 2.5 than to evaluate total PM 2.5 itself. Apparent good performance for total PM 2.5 does not indicate whether modeled PM 2.5 is predicted for the right reasons (the proper mix of components). If performance of the major components is good, then performance for total PM 2.5 should also be good. The EPA recommends calculating statistics for components of PM 2.5 and PM 2.5 precursors. Useful metrics include mean fractional bias and mean fractional error, normalized mean bias, and normalized mean error. Formulas for estimating these metrics are given in the Modeling Guidance (Modeling Guidance, p. 203

- 204).

Other statisti cs such as mean bias, mean error, root mean square error, correlation coefficients, etc. should also be calculated to the extent that they provide meaningful information.

Since modeling for the PM 2.5 NAAQS will likely require modeling different times of

y ear, season

- specific statistics and graphic displays are helpful for evaluating and diagnosing model performance. Statistics and graphics can be averaged for various time scales. For example, statistical metrics and scatter plots can show daily averaged am bient modeled pairs, monthly averaged pairs, quarterly (or seasonal averaged) pairs, or annual average pairs. Each of these averaging times can provide useful information. The EPA recommends a range of different averaging times for annual or seasonal model ing. At a minimum, a state should examine daily averaged pairs and seasonal (or quarterly) averaged pairs. Because statistics and plots tend to look “better” as the averaging time increases from daily to monthly to quarterly to annual, dailyTSD for the Proposed Action

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- Region 9 Page 43 pairs should a lways be examined to ensure a detailed look at model performance on the time scale of the Federal Reference Method (FRM) and Speciation Trends Network (STN) measurements (24

- hour average).

Soccer plots provide a convenient way to display a summary of mode l performance (including bias and error at the same time). Bugle plots 36 have variable bias and error goals, based on ambient concentrations. This allows for a higher percentage error and bias at very low concentrations. This recognizes the fact that models often have difficulty in accurately predicting near background concentrations and may be useful to prioritize examination of model performance within and near the non

- attainment area(s) of interest. Additionally, priority may be placed on examination of t he days that are potentially used in the attainment test (e.g., the days with ambient concentrations above 35 μg/m 3 for the 2006 24

- hour PM 2.5 NAAQS.)

The performance evaluation is presented in Chapter 5 of Appendix V of the 2012 PM 2.5 Plan. The CMAQ 2008 base

- year 24

- hour PM2.5 Component Species performance statistics are presented. The analysis includes predicted concentrations and observations for the six component species and total mass at the 6 SASS sites, as well as estimates of bias and error for ea ch component at each monitoring site.

The three western Basin Los Angeles County sites analyzed had a total mass absolute prediction accuracy that exceeded 25 percent of the observed average. Prediction accuracy estimated for the three remaining sites me asured approximately 20 percent or lower. In general, normalized bias was lowest for nitrate and highest for sulfate. The only systematic bias was evident for EC, whereby the tendency was to under predict observations.

One element observed during the 2008 simulation evaluation was that the eastern portion of the Basin predicted low concentrations of secondary aerosols when high wind “Santa Ana” conditions were observed. This generalized wind condition also impacted the western portion of

the Basin but to a lesser extent. The days impacted by the high winds were clustered in the first and fourth quarters.

The plan also discusses the base

- year model performance stress test evaluation. EPA’s modeling guidance as well as the draft modeling protocol outline a series of basic stress tests that can be applied to the base case simulation to determine the level of sensitivity of model performance to key parameters defining the simulations. These stress tests include modifying the boundary conditions, and introducin g gross changes in the meteorological and emissions profiles. The goal for these analyses is to see if any one factor is unduly biasing model performance and in doing so jeopardizing the validity of the analysis. The plan presents the suite of performance stress tests applied to the CMAQ (and CAMx) PM2.5 simulations. The results of the tests are not presented, be the summary of the outcome of the CMAQ testing indicated that

36 Fr a cti o n al e rro r a n d b ias te n d to b e la r g e at s m all c o n c e n tra t i o ns
, s i n ce t h e n t h e u n c er t a i n t y c a n b e n e ar l y as b ig as

t h e c o n c e n trati o n

. S i n ce f r a c ti o n al e rro r v a r ies r elati v e l y s l o w l y w i t h c o n c e n trati o n
, b u t t h e n g r o w s la r g er at l o w

c o n c e n trati on s
, t h e sh a p e o f t h e p l o t r es e m b l e s a l o n g t ub e w i t h a f

la r ed e n d at l o w c o n c e n tra t i o ns
, r e m i n i s ce n t o f a b ug le.TSD for the Proposed Action

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- Region 9 Page 44 the model responded in an expected manner to the changes in simulation parameters an d emissions profiles outlined in the stress tests.

The EPA f

inds t he a ir q u a l i t y model p e r fo r ma n c e is a d e qu a te. More c o mp l e te
do c umentation of the stress test evaluation results would h a v e b ee n d e si r a ble.

k. Modeled Attainment Test

A modeled attainment test is an exercise in which an air quality model is used to simulate current and future air quality. If future estimates of PM 2.5 concentrations are less than the NAAQS, then this element of the attainment test is satisfied. The EPA’s r ecommended test is one in which model estimates are used in a relative rather than absolute sense. That is, we take the ratio of the model’s future to current (baseline) predictions at monitors. We call these ratios relative response factors (RRF). Future PM 2.5 concentrations are estimated at existing monitoring sites by multiplying a modeled relative response factor at locations near each monitor by the observation

- based, monitor

- specific, baseline design value. The resulting predicted future concentration s are compared to the NAAQS.

The PM 2.5 attainment test reflects the fact that PM 2.5 is a mixture. In the test, ambient

PM 2.5 is divided into major species components, so EPA’s test is called the Speciated Modeled

Attainment Test (SMAT). There is mass asso ciated with sulfates, nitrates, ammonium, organic carbon, elemental carbon, particle

- bound water, other primary inorganic particulate matter, and passively collected mass. Note that FRM monitors do not measure the same components and do

not retain all of t he PM 2.5 that is measured by routine speciation samplers, and therefore cannot be directly compared to speciation measurements from the STN. By design, the FRM mass

measurement does not retain all ammonium nitrate and other semi

- volatile materials (negativ e sampling artifacts) and includes particle

- bound water associated with sulfates, nitrates and other hygroscopic species (positive sampling artifacts). This results in concentrations (and percent contributions to PM 2.5 mass) which may be different than the ambient levels of some

PM 2.5 chemical constituents. Therefore, we recommend a SMAT technique which uses an FRM mass construction methodology which results in reduced nitrates (relative to the amount measured by routine speciation networks), higher mass as sociated with sulfates and nitrates (reflecting water included in gravimetric FRM measurements) and a measure of organic

carbonaceous mass which is derived from the difference between measured PM 2.5 and its non

organic carbon components. This approach is sometimes called SANDWICH, for s ulfate,

a djusted n itrate, d erived water, inferred c arbonaceous material balance approac h (Modeling Guidance, p. 47).

The modeled attainment test in the plan was based on the following steps:

1. A separate RRF is calculated for each monitoring site for each of the PM 2.5 components (except passive mass, represented by a field blank concentration of 0.3

- 0.5 μg/m 3 ).

2. Future PM 2.5 design values are estimated at existing monitoring sites by multiplying modeled

RRFs near each mo nitor by the observed component

- specific design value. This latter quantityTSD for the Proposed Action

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- Region 9 Page 45 is estimated using measured site

- specific design values for PM 2.5 in concert with available measured composition data.

3. Future site

- specific PM 2.5 design values at a site are est imated by adding the future year

values of the seven PM 2.5 components. If all future site

- specific PM 2.5 design values are less than or equal to the concentration specified in the NAAQS, the test is passed (Modeling Guidance, pp. 15

- 16).

The future year modeling for the 2012 PM2.5 Plan is discussed in Chapter 5 of Appendix V. A set of RRFs were generated for each future year simulation. RRFs were generated for the ammonium ion (NH4), nitrate ion (NO3), sulfate ion (SO4), organic carbon (OC), elemental

car bon (EC) and a combined grouping of crustal, sea salts and metals (Others). A total of 24 RRFs were generated for each future year simulation. Water vapor was determined using U.S. EPA’s regression model approximation of the AIM model based on simulated c oncentrations of the ammonium, nitrate and sulfate ions.

Future year concentrations of the six component species were calculated by applying the model generated quarterly RRFs to the speciated 24

- hour PM2.5 (FRM) data sorted by quarter

for each of the fiv e years used in the design value calculation. The 32 days in each year were

then re

- ranked to establish a new 98th percentile concentration. The resulting future year 98th percentile concentrations for the 5

- years were subjected to weighted averaging for t he attainment demonstration. Future year PM2.5 24

- hour average design values are presented for 2014, and 2019 to (1) demonstrate the future baseline concentrations if no further controls are implemented; (2) identify the amount of air quality improvement n eeded to advance the attainment date to 2014; and (3) confirm the attainment demonstration with implementation of the proposed PM2.5 control strategy. The results are presented in Table II

- B

- 4 , CMAQ 2014 24

- hour PM2.5 Controlled Predictions (in μg/m 3 ).

TableII

- B

- 4 : CMAQ 2014 24

- hour PM2.5 Controlled Predictions (μg/m 3 )

Locations NH4 NO3 SO4 OC EC Others Water Blank Mass

Anaheim 2.89 7.52 2.20 6.61 2.79 3.53 1.45 0.50 27.49

S. Long Beach 2.96 6.86 2.52 5.55 3.06 1.98 1.37 0.50 24.79

Fontana 4.71 11.80 1.86 5.26 3.27 3.45 2.10 0.50 32.94

N. Long Beach 3.76 8.24 3.39 5.79 2.80 2.08 1.70 0.50 28.27

Los Angeles 4.56 10.49 3.32 5.62 2.68 2.64 2.00 0.50 31.80

Mira Loma 4.92 12.84 1.96 5.61 2.88 3.24 2.33 0.50 34.28

Rubidoux 4.71 12.95 1.95 4.73 2.47 2.77 2.44 0.50 32.51

Source: 2012 Plan, Appendix V., page V

- 5

- 40TSD for the Proposed Action

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- Region 9 Page 46 The EPA f

inds t he P lan ’ s a t t a in m e nt t e st pro c e dure to be a d e qu a te for the impr ac t i ca bi l i t y d e m onstr a t i on.

l. Unmonitored Area Analysis

In addition to a modeled attainment demonstration, the EPA recommends use of an unmonitored area analysis (UAA). This type of analysis is intended to ensure that a control strategy leads to reductions in ozone or PM 2.5 at other locations which could have b ase year and future baseline (projection year) design values exceeding the NAAQS if a monitor were deployed there.

The UAA should identify areas where future year design values are predicted to be greater than the NAAQS. The UAA for a particular nonattain ment area is intended to address potential problems within or near that nonattainment area. The analysis should include, at a minimum, all nonattainment counties and counties surrounding the nonattainment area (located within the state). In order to examin e unmonitored areas in all portions of the domain, the EPA recommends that a state use interpolated spatial fields of ambient data combined with gridded modeled outputs (Modeling Guidance, p. 29).

Gradient adjusted spatial fields are first created for the base year. Future year estimates can then be created by applying gridded RRFs to the gradient adjusted spatial fields. The basic steps are as follows (Modeling Guidance, p. 30):

1. Interpolate base year ambient data to create a set of spatial fields.

2. Adjust the spatial fields using gridded model output gradients (base year values).

3. Apply gridded model RRFs to the gradient adjusted spatial fields.

4. Determine if any unmonitored areas are predicted to exceed the NAAQS in the future.

As de scribed earlier in this chapter, speciation profiles from Speciation Air Sampling System ( SASS) sites in adjacent or collocated grid cells are used in the formal attainment demonstration for Mira Loma and also South Long Beach. 37 With interpolation of the S ASS speciation profiles, attainment demonstrations can be directly conducted for the remaining grid

cells where FRM mass data has been collected over the 5

- year period (2006

- 2010). To date, no specific test has been proposed by the EPA to address testing a ttainment at grid cells where no speciated and/or FRM data is available. The form of the revised attainment test adds

37 2012 PM 2.5 Plan, Appendix V, p. V

- 5

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- Region 9 Page 47 complication in that it requires assessing the impacts for 32 days per year, for five years, at each unmonitored grid cell.

The methodolo gy used to assess the unmonitored grid cell impact follows. First, a subset of the full modeling domain covering the Basin was selected for the analysis. The western most grid column (70) was aligned with coastal Los Angeles. The eastern most column (100) touched Banning Pass, the southern boundary was located in row 45 in northern San Diego, and the northern most row (65) corresponding to the northern portion of the San Fernando Valley extending across the San Gabriel and San Bernardino Mountains. A review of the 24

- hour

PM 2.5 FRM data and design values from sites located outside of this inner domain indicated that concentrations were significantly lower than in those observed in the primary non

attainment portion of the Basin.

The next task included spat ial interpolation (1/r) of the six SASS speciation splits to define the split profiles for each grid cell. The split percentages were then multiplied by the

simulation

- derived RRFs, for each of the four seasons. FRM data, based on every third day sampling from 21 Basin monitoring sites which were extracted from the EPA’s Air Quality System database for each year of the 5

- year period. The highest 8 concentrations sampled in each quarter were selected to generate a data set that included 160 days. The data fo r each day were then interpolated throughout the inner

- domain using an inverse distance weighted scheme (1/r) to develop a matrix of grid

- specific 24

- hour PM 2.5 concentrations for all 160 days. Note that extraction of data on a frequency of every third day was selected so that there was consistency in the numbers of FRM data samples used in the analysis. In general, the number of valid yearly samples using the third day extraction was between 100

- 150 days, and thus allowed the analysis to focus on the proje cted 3rd highest value (of the 32 days evaluated) in each year as the 98th percentile value.

The interpolated FRM data were then multiplied by the seasonally sorted, RRF

interpolated species fractions to project the future year 24

- hour PM 2.5 distribution for each of the five years. The attainment calculation then tested the weighted 5

- year average 98th percentile concentration at each grid. Table V

- 5

- 23, shown below, provides a summary of the unmonitored area analysis. Listed are the top 15 projected grid cell center concentrations for the 2014 controlled scenario and the respective 2008 interpolated center grid concentration. The second set of columns provides the list of grid cells with the maximum projected 2014

controlled 24

- hour PM 2.5 design value mod eled as if every grid in the Basin had Mira Loma’s species profile. This calculation was conducted to test the distance

- weighted interpolation hypothesis and the impacts of varying species profiles and RRFs.

The interpolated 2008 grid center design values and 2014 projected determined from the unmonitored area analysis lined up closely with the station design values. The 2014 controlled maximum projected 24

- hour PM 2.5 design value of 31.2 μg/m 3 occurred at the center of the Mira Loma grid cell (89,58). Since no cell in the modeling domain was projected to have a 2014 controlled design value above that of cell (89,58), the Basin passes the unmonitored area portion of the 24

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- Region 9 Page 48 This analysis demonstrates that the relative response to the control program is more effective in the Eastern Basin while portions of the western Basin do not exhibit the equivalent response to the implementation of the proposed control strategy.

The EPA finds that the UAA is ad e q u a te for purp os e s of t h e i m pr a c t i ca bi l i t y d e monstr a t i on.

m. Weight of Evidence

States should perform complementary analyses of air quality, emissions and meteorological data and consider modeling outputs other than the results of the attainment test. Such analyses are instrumental in guiding an air quality modeling application. The r esults of corroboratory analyses may sometimes be used in a weight of evidence determination to show that attainment is likely despite modeled results, which may be inconclusive. The further the attainment test is from being passed ( i.e., the higher the mo deled pollutant levels are above attainment levels), the more compelling contrary evidence produced by corroboratory analyses must be to draw a conclusion different from that implied by the modeled attainment test results. (Modeling Guidance, p. 17). Suppl emental analyses could include additional modeling using alternative models and inputs, modeling apportionment and process analysis tools, alternative metrics (such as change in the number of grid cells above the NAAQS), trends in ambient air quality, tren ds in emissions, receptor modeling, and indicator species approaches.

The weight of evidence in the plan is based on trends in emissions. The plan concluded that while the projected NOx and direct PM2.5 emissions trends decrease at a reduced rate

between 2012 and 2019, it is clearly evident that the overall significant reductions will continue to result in lower nitrate and direct particulate contributions to 24

- hour PM2.5 design values.

The EPA finds that the weight of evidence presented in the plan is ad e q u a te for purp os e s of t h e i m pr a c t i ca bi l i t y d e monstr a t i on.

3. Data in the July 28, 2015, Request to U.S. EPA to Reclassify the South Coast Air Basin as

Serious Nonattainment for the 24

- hour PM2.5 National Ambient Air Quality Standard (NAAQS)

In a lett er dated July 28, 2015, the SCAQMD requested that the EPA reclassify the South

Coast Air Basin as a Serious nonattainment area for the 24

- hour PM 2.5 NAAQS based on monitoring data indicating attainment is not practicable by the December 31, 2015 attainment date. SCAQMD staff also requested that the EPA approve any applicable elements in the Moderate SIP submitted previously and consider the data submit ted herewith in conjunction with the 2012 and 2015 submittals as a demonstration that the area cannot practicably attain by the

Moderate area date.TSD for the Proposed Action

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- Region 9 Page 49 Air quality measured at t he Mira Loma air quality monitoring station exceeds the 24

- hour

PM 2.5 NAAQS, and preliminary ambient 24

- hour PM 2.5 measurements at that station for the first quarter of 2015 indicate that the Basin will not attain the NAAQS by the moderate area statutory deadline of 2015. The letter attributes the inability to attain the NAAQS largel y to the lack of rainy days in January and February of 2014 and 2015, which experienced 33 percent of average rainfall. The effect of the drought on air quality was also discussed in the Draft Supplement to the 24

- Hour PM 2.5 State Implementation Plan for the South Coast Air Basin. 38

4. Weight of Evidence in the Supplement to the 24

- Hour PM 2.5 State Implementation Plan for

the South Coast Air Basin

The Supplement provided an update to the analysis and a discussion of the d rought’s impact on air quality. 39 The west coast of the U.S. has experienced a severe drought for the past several years with 2013 annual rainfall total measured at Downtown Los Angeles of 3.6 inches, far below the 14.9 inch long term average.

 Rainfall events of 0.01 inches of rain or mo re were 25 percent lower than the average of 28 days typically occurring during the 1 st and 4 th quarters of the year.

 Under the drought conditions, Mira Loma 24

- hour PM 2.5 98 th percentile concentrations experienced a reversal in the long

- term trend of dec lining concentrations rising from a 2012 value of 35.1 μg/m 3 to 37.5 in 2013.

 Based on a conservative analysis of the impact of rain fall events on the 98 th percentile concentration, the drought accounted for roughly 1.6 μg/m 3 additional mass to the

obser ved 98 th percentile concentration. 40

A discussion of the rain event

- concentration impact was provided in Attachment B to the 2015 Supplement, and is discussed below. Based on this analysis, the SCAQMD anticipated

that the 2014 Basin 24

- hour PM 2.5 design value (measured at Mira Loma) based on the 2012

- 2014 3

- year average of the 98 th percentile concentration will exceed 35.4 μg/m 3 due to the observed continuation of the drought.

Background

The 2014 attainment demonstration was based on simulated RRFs appl ied to a weighted 2008 design value. The 5

- year weighted PM 2.5 design value incorporated 98 th percentile concentrations from 2006 through 2010. The five

- year period used for the design calculation covered a meteorological period, when assessed for the fre quency of rainfall events and precipitation accumulations, was essentially average compared to the long term (50+ year)

38 Draft Supplement to the 24

- Hour PM2.5 State Implementation Plan for the South Coast Air Basin, January 2015

39 2015 Supplement, Attachment A, p. A

- 2.

40 Ibid. (?)TSD for the Proposed Action

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- Region 9 Page 50 statistics. As a consequence, the 2014 projected 24

- hour PM 2.5 design value for Mira Loma assumed a similar window of average precipita tion events and rainfall totals with the concurrent natural pollution dispersion potential associated with the unstable weather.

Through October, the drought continued and only 8 rain days were observed at Downtown Los Angeles in 2014. More specifically , no rain fell in January with only two days of minor precipitation in February before the 26 th of the month. Note that historically, the majority of exceedances of the standard occur between November and February.

SCAQMD evaluated the impact of the drought on 24

- hour PM 2.5 levels by first developing a methodology to correct for variations in rainfall frequency and then applying that methodology to the trend of ambient PM2.5 to determine the likelihood of future comp liance.

Accounting for Seasonal Variations in Rainfall Frequency

As described above, the West Coast of the U.S. has been impacted by a multi

- year drought that has reduced the frequency of rain events and increased the likelihood for atmospheric stagnatio n. A question has arisen as to what would be the impact to the 2015 attainment demonstration if the drought continues beyond 2014. To assess this potential situation, an algorithm was generated to adjust the predicted annual PM 2.5 98 th percentile

concentra tion based on the deviation from the average expected rain frequency.

Estimating the Impact of the Drought on the PM 2.5 Trend

The supplemental analysis first presents the 24

- hour PM 2.5 data for the Mira Loma design site including the observed 98 th percen tile concentration from 2006 through 2013 and the three year average design value for 2008 through 2013. It then outlines the steps to estimate the drought impact to the observed Mira Loma annual 98 th percentile concentration and the methodology to estimat e the impact to both 2014 and 2015.

The EPA finds that the weight of evidence presented in the supplement to the plan useful

for the purp os e of t h e i m pr a c t i ca bi l i t y d e monstr a t i on, because it contributes to the understanding of current air quality and the d rought’s impact on air quality.

5. 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 demonstration, and the demonstration of impracticability in the 2012

PM 2.5 Plan and Supplement.TSD for the Proposed Action

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- Region 9 Page 51 

### C

. PM 2 .5 

### P recur s o r s

1. R e quir e ments for the Control of P M 2 .5 P r e c ur s ors

The c omposi t ion of P M 2 .5 is compl e x a nd hi g h l y v a ri a ble due in p a rt to the la r g e

c ontribution of s ec ond ar y P M 2 .5 to to t a l fine p a rt i c le m a ss i n most l o ca t i ons, a nd to t he

c omp l e x i t y of s ec ond a r y p a rti c le f or m a t i on p r o ce s s e s. A large num b e r of p oss i ble c h e m i ca l

r e ac t i ons, oft e n no n

- l i n e a r in n a tur e
, c a n c on v e rt g a s e ous S O 2 , N O
x , V O C a nd a m m onia to

P M 2

. 5 , making them p re c urso r s to PM 2

. 5

. 41 F orm a t i o n of s ec ond a r y P M 2 .5 may a lso d e p e nd on

a t m osph e ric c ondi t ion s , including sol a r r a diation, temp e r a tu r e
, a nd r e lative hum i di t y
, a nd the

in t e r a c t i ons of p r ec urso r s with pr ee x is t ing p a rti c l e s a nd with cloud or f o g d ropl e ts

. 42

The 2007 P M 2

. 5 I

mp l e ment a t i on Rule c ontain e d r e but t a ble p re sumpt i ons c on ce rni n g the

f o u r P M 2

. 5 pr e c urso r s a ppl i c a ble to a t t a in m e nt p l a ns a nd c ontrol m ea sur e s r e la t e d to t hose plans.

S e e 40 C F R 51.1002 (c ). Alt h ou g h the rule includ e d p r e sumpt i ons th a t s t a tes should add re s s S O 2

a nd N O x e m i ss i ons in their a t tainment plans, it a lso i n c luded p re sumpt i ons th a t r e g ulation of

V OCs a nd a m m onia wa s not n e ce ssa r y

. S p e c ifi ca l l y , in 40 C F R 51.1002 (c ), the EPA p r ovided,

a mo n g other th i n g s, that a sta t e w a s “ not r e qu i r e d to add r e ss VOC [ a nd a m m onia] a s . . . P M 2

. 5

a t t a in m e nt p l a n pr e c u rso r[ s] a nd to ev a luate sour c e s of V OC [ a nd a m m onia] e m i ss i ons in the

state for c ontrol m e a sur e s,” unless the state or the EPA p r ovided a n a p p ro p ri a te t ec hni c a l

d e monstr a t i on showing t h a t emissions f r om s o urc e s of th e se pol l utants “ s i g nifi c a nt l y c ontribut e ”

to P M 2 .5 c on ce ntr a t i ons in the non a t t a in m e nt a r e a

. 40 C F R 51.1002 (c ) ( 3 ), ( 4); s e e a lso 2007

P M 2

. 5 I mp l e men t a t i on Rule, 72 F R 20586 a t 205 8 9

- 97 ( A pril 25, 2007).

I n NR D C , ho w e v e r, t h e D.C. C ir c uit r e mand e d t h e EPA ’ s 2007 P M 2

. 5 I mp l e ment a t i on Rule in i ts entir e t y , including t he pr e sumpt i ons c on c e r n ing V O C a nd a m m onia in 40 C F R

51.1002. S e e NR D C v . EPA , 706 F .3d 428 ( D .C. Cir. 2013 ) . Althou g h the c o u rt e x pr e ss l y d e c l i n e d to d ec ide the sp e c ific c h a l le n g e to t h e s e pr e sumpt i o n s ( s e e 706 F .3d a t 437, n. 10
( D .C. Cir. 2013 ) ), the c ourt c i t e d CAA s e c t i on 189 (e ) 43 to support its o bs e rv a t i on that

“ [ a ] m m onia is a pr e c u rsor to fine p a rti c ulate m a t t e r, m a king it a p r ec u rsor to b o th P M 2 .5 a nd

P M 1 0 ” a nd that “ [ f

] or a P M 10 non a t t a in m e nt a r e a g ov e r n e d b y sub p a rt 4, a p r e c u rsor is

pr e sumpt i v e l y regulat e d.” 706 F .3d a t 436, n. 7 ( c i t ing CAA s e c t i on 189 (e ) ) . Consistent with

t he NR D C d ec is i on, EPA now in t e rp re ts the Ac t t o r e qui r e that u n d e r subp a rt 4, a state must

e v a luate a ll P M 2 .5 pr e c urso r s f or re g ulation unless the st a te provid e s a d e monstr a t i on a d e q u a te

to r e but t he pr e sumpt i on f o r a p a rti c ular pr e c urs o r in a p a rti c u l a r non a t t a in m e nt a r ea

.

The provisions of subpart 4 do not define the term “precursor ” for purposes of PM 2.5 , nor do they explicitly require the control of any specifically identified particulate matter (PM)

41 E P A

, A ir Q u ali t y C r ite r ia f o r P a r tic u late M a tter ( E P A / 600 / P

- 99 / 002 aF, Oct ob er 20 0 4)

, Ch a p ter 3

. 42 E P A

, R e g u lat o r y I m

p a c t A n a l y s i s f

o r t h e F i n al R e v i s i o n s to t h e Nati o n al A m b i e n t A ir Q u ali t y St a n d a rd s f o r
P a r tic u late M a tter ( E P A

- 452 /R

- 12

- 005

, De c e m b er 2012)

, p

. 2

- 1.

43 Secti o n 189( e) o f t h e C AA s t ates t h at “ [ t ] h e c o n tr o l r e q u ire m e n ts a pp lica b le u n d er p la n s i n e f f e c t un d er t h is p a r t
f o r m a j o r s tati o n a r y s o u r c e s o f P M 10 sh all also a pp l y to m a j o r s tati o n a r y s o u r c e s o f P M 10 pr e c u r s or s
, e x c ep t w h e r e

t h e A d m i n i s trat o r d ete r m i n e s t h at s u ch s o u r c e s d o n o t co n tr i b u te s i gn i f ic a n t l y to P M 10 le v e ls w h i c h e x c e ed t h e

s ta n d a r d in t h e a r e a .”TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 52 precursor. The statutory definition of “air pollutant

, ” however, provide s that the term

“ includes any precursors to the f or mation of a n y a ir pollut a nt, t o the e x tent the A dm i nis t r a tor

h a s identifi e d su c h pr e c u rsor or p r e c u r s ors f or the p a rti c ular pu rpose for whi c h t h e te r m ‘ a ir pollutant’ is u s e d.” CAA s ec t i on 302 ( g ). T h e EPA h a s identifi e d S O 2 , N O x , V O C, a nd

a m m onia a s pr e c urso r s to t he fo r mation of P M 2

. 5

. A cc ordin g l y , the a t t a in m e nt p l a n

r e qui r e ments of subp a rt 4 p re sumpt i v e l y a pp l y to e m i ss i ons of a ll four pre c ursor pol l utants

a nd dir ec t P M 2 .5 f

r om all t y p e s of s t a t i on a r y
, a r e a
, a nd mob i les sou r ce s, e x ce pt as oth e r w ise

p r ovided in the A c t ( e .g. C AA s ec t i on 189 ( e ) )

.

S ec t i on 189 (e ) of the A c t r e quir e s t h a t the c ontrol r e quir e ments f o r m a jor s t a t i on a r y

sour c e s of di rec t P M 1 0 a lso app l y to m a jor stationa r y so u rc e s of P M 1 0 pr e c urso r s, e x ce pt wh e r e
the Admin i str a tor d e te r m i n e s that su c h sour ce s do n o t cont r ibu t e si g nifi c a nt l y to PM 1 0 lev e ls

t h a t e x cee d the st a nd a rd in the a re a

. S ec t i on 189 ( e ) c o ntains the on l y e x pr e ss ex ce pt i on to t he

c ontrol r e quir e ments und e r sub p a rt 4 ( e .g., r e quir e m e nts f or RACM and RACT, B ACM and

B ACT, most strin g e nt m ea su r e s, a nd NS R ) f or sou r c e s of dir ec t P M 2 .5 a nd P M 2 .5 pr e c ursor

e m i ss i ons. Althou g h s e c t i on 189 (e ) e x pl i c i t l y a dd r e sses on l y major stationa r y sour c e s, the E P A

inte r pr e ts the Ac t as a uthori z ing it t o a lso det e rmin e , und e r appro p ri a te c i r c ums t a n c e s, that

r e g ulation of ce rt a in P M 2 .5 pr e c urso r s f r om o t h e r sou r c e ca t e g o r ies in a g iven no n a t t a in m e nt

a r e a is not n ece ss a r y

. F o r e x a mp l e , und e r t he EPA ’ s lo n g st a nding in t e rp r e tation of t h e c ontrol

r e qui r e ments that a pp l y to s t a t i on a r y
, a r e a
, a nd mob i le s ou r ce s o f P M 1 0 pr e c urso r s a re a

- w ide

und e r CAA s ec t i on 172 (c ) (1) a nd su b p a rt 4 ( s e e G e n e r a l P re a mb le , 57 F R 13498 a t 1 3 539

- 42),

a state m a y d e monstr a te in a S I P su b m i t t a l that c ontrol of a c e rt a in pr ec u rsor pol l utant is not

ne ce ssa r y in l i g ht of its in s i g n i fi ca nt c ontribution t o a mb i e nt PM 2.5 lev e ls i n the non a t t a in m e nt

a rea

. 44

W e a re e v a luating t h e S outh Coast P M 2

. 5 P lan in acc ord a n c e with t he pr e sumpt i on

e mbod i e d with i n subp a rt 4 th a t all P M 2

. 5 p r e c urs o rs must be a dd r e ssed in the st a te ’ s e v a luation of pot e nt i a l cont r ol me a sur e s, unl e ss t he sta t e a d e q u a te l y d e monstr a t e s that e m i ss i ons of a

p a rti c ular p r ec ursor do not c ontribute si g nifi c a nt l y t o a mb i e nt P M 2

. 5 lev e ls t h a t e x cee d the P M 2 .5 N A A Qs in the non a t t a in m e nt a r e a.

2. Ev a luation of P r e c u rsors in 2012 P M 2 .5 P lan a nd 2015 S upplem e nt

The 2012 P M 2 .5 P lan discusses the five primary pollutants that contribute to the mass of

the ambient aerosol ( i.e., ammonia, NOx, SOx, VOC, and directly emitted PM 2.5 ) , and states that various combinations of reductions in these pollutants could all provide a path to clean air. 45 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 PM 2.5 air quality

. 46 As presented in the weight of evid ence discussion, trends of PM 2.5 and NOx emissions

44 C o u r ts h a v e u p h eld t h is a ppro a c h to t h e r e q u ir e m e n t s o f s u b p a r t 4 f o r P M 10

. S e e , e

. g. , A ss o c. o f I rr it a ted

Reside n ts v. EPA, et a l

., 4 2 3 F. 3 d 98 9 ( 9 th C ir. 2005)

. 45 2012 PM 2.5 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 PM 2.5 Concentrations.

46 2012 PM 2.5 Plan, Appendix V, Attachment 8, Relative Contributions of Precursor Emissions Reductions to

Simulated Controlled Future

- Year 24

- hour PM2.5 Concentrations.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 53 suggest a direct response between lower emissions of PM 2.5 and NOx and improved air quality.

The Community Multi

- Scale Air Quality model ( CMAQ ) simulations in the Plan provide a set of

response factors for direct PM 2.5 , SOx, NOx, and VOCs , based on i mprovements to ambient 24

- hour PM 2.5 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.

T he 2012 PM 2.5 Pl a n and 2015 Supplement d e s c ribe how r e du c t i ons in NOx , SO 2 , VOC

and ammonia e m i ss i ons c ontribute to attainment of the P M 2

. 5 stand a rd in the South Coast a r e a and contains the District’s evaluation of available control measures for all four of these P M 2

. 5 precursor pollutants, in addition to direct P M 2

. 5 , consist e nt wi t h the r eg u l ato r y presumpt i ons under subpart 4. The Plan 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. 47 W e discuss t he state’s e v aluation of potential control mea s ur e s for direct P M 2

. 5

, N O x , S O 2 , VOC and

a m m onia in section II. D, “Reasonably Available Control Measures/Reasonably Available Control Technology.”

47 In a separate rulemaking to approve revisions to SCAQMD’s nonattainment New Source Review (NNSR) program, the EPA det ermined that the control requirements applicable under the SCAQMD SIP to major stationary

sources of direct PM 2.5 also apply to major stationary sources of NOx, SOx, and VOC, and that major stationary sources of ammonia do not contribute significantly to P M 2.5 levels which exceed the PM 2.5 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.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 54 

### D. Reasonably Available Control Measures/Reasonably Available Control Technology (RACM/RACT)

1. Requirement s for RACM/RACT

T he general subpart 1 attainment plan requirement for RACM and RACT is described in CAA section 172(c)(1)

, which requir es that attainment plan submissions “provide for the implementation of all reasonabl y 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 PM 2.5

u nder subpart 4 likewise impose upon states an obligation to develop attainment plans that require RACM on sources of direct PM 2.5 and those PM 2.5 precursors determined to be subject to the RACM/RACT requirement

. CAA s ection 189(a)(1)(C) requires that Moderate area PM 2.5 SIPs contain provisions to assure that RACM are implemented by no later than 4 years after designation of the are a

. 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 PM 2.5 and PM 2.5 precursors in the

nonattainment ar ea as expeditiously as practicable but no later than 4 years after designation. 48

Under the RACM and RACT requirement s, all available controls should be evaluated, and reasonable controls should be adopted.

The terms RACM and RACT are not specifically defin ed in the Act , nor do the provisions of subpart 4 specify how states are to meet the RACM and RACT requirements. In longstanding guidance, however, the EPA has interpreted the RACM requirement to include any potential control measure for a point, area, on

- road and non

- road emission source that is technologically and economically feasible (General Preamble at 13540). The EPA has historically define d RACT as the lowest emission limitation that a particular stationary source is capable of meeting by the applic ation of control technology ( e.g. , devices, systems, process

modification s , 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 t echn olog ic al 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 (i.e., increased water pollution, waste disposal, and energy requirements. ( 57 FR 18070, 18073 ).

An evaluation of e conomic feasibility should include consideration of factors such as cost per ton of pollution reduced (cost

- effectiveness)

, capital costs, a nd annualized cost (57 FR 18070, 18074)

. Absent other indications, t he 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 oth er sources in a source category have in fact applied the control technology

, process change, or measure in question in similar circumstances. Id

.

48 This inte rpretation is consistent with guidance provided in the General Preamble at 13540.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 55 2

. RACM/RACT Analysis in the 2012 PM 2.5 Plan and 2015 Supplement

The 2012 PM 2.5 Plan’s RACM/RACT evaluation for direct PM 2.5 , NO
x
, VOC , NH 3 and

SO
x sources is presented in Appendix VI and in Attachment D to the 2015 Supplement . SCAG’s RACM analysis for mobile sources is detailed in Appendix IV

- C ( “ Regional Transportation Strategies and Control Measur es ” ). CARB’s RACM evaluation for mobile sources is included in Appendix VI of the 2012 PM 2.5 Plan

. The evaluation of potential controls is presented by pollutant and then by rule type/ source category. For stat ionary and area source categor ies , the comparison to recent ly

- issued EPA

CTGs is broken down by the current District rule or rules that apply to that source category. See

2012 PM 2.5 Plan, Appendix VI, and 2015 Supplement, Attachment D )

.
For the 20 12 PM 2.5 Plan , the District, CARB and SCAG each undertook a process to identify and evaluate potential measures that could contribute to expeditious attainment of the

PM 2.5 standards in the South Coast nonattainment area. We describe these processes below.

The Distric t conducted a multi

- step process to identify candidate RACM measures for for

the 2012 PM 2.5 P lan that are technologically and economically feasible. The first step was t o 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. T he 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

,

 further reduce VOC emissions from coatings, solvents, and various consumer
products focusing on reformulations or alternatives to VOC

- based solvents,

 conduct a technology revi ew 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 pl ants, 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 p rocess was to look at EPA’s list of suggested

control measures for PM 2.5 nonattainment areas described in the 2007 PM 2.5 Implementation Rule. The District summarized the results of this analysis in Table VI

- 3

, Appendix VI of the

2012 PM 2.5 Plan. This analy sis shows that the District either has a pre

- existing rule or has developed a control measure for the 2012 PM 2.5 Plan to address each of EPA ’s suggested types

of measures

.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 56 The third step in the District’s RACM process involved analyzing the District’s rules for compliance with the RACT standard . The results of this analysis are summarized in Table VI

- 4

, Appendix VI ( page VI

- 10 ) of the 2012 PM 2.5 P lan . The District further su pplemented these analyses in the 2015 Supplement, Attachment D , Tables D

- 4 to D

- 8 to address RACM and

RACT requirements for direct PM 2.5 and all PM 2.5 precursors
, and to provide reasoned justifications for control measures that were not adopted

. A few ex amples of RACT

- level rules in the South Coast include Rules 1146 and 1146.1, which control NOx from industrial and institutional boilers, R ule 11 3 3.3 , g reenwaste composting , which in addition to providing a RACT level of control, also controls fugitives

, R ule 1171, Solvent Cleaning, and Rule 1130, Graphic Arts. 49

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 rules from four other air districts in California (San Joaquin Valley, Sacramento Metropolitan, Ventura, and San Francisco B ay Area)

, the Dallas

- Fort Worth and

Houston

- Galveston areas in T exas , New York

, and New Jersey. A summary of this analysis is presented in the 2012 PM 2.5 Plan, Appendix VI, Table VI

- 5 and in the 2015 Supplement,

Attachment D . Table VI

- 5 identifies those ru les from other areas that, based on the District’s
review, may be more stringent in some respects than South Coast rules. With respect to rules 1115, 1130, and 1168 , the Plan states the District ’s intention to provide further analyses at a later

time

. See 2012 PM 2.5 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 S upplement also states that the Distric t 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 t he 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. T he two facilities subject to

Rule 1115 , however, have very small emissions

, a total of about 0.02 tpd of VOC. 50 See 201 5 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)

49 The technical support documents for EPA’s rulemaking actions on these rules are available at: http://yosemite.epa.gov/r9/r9sips.nsf/AgencyProvision/5F5287B726E9E6F488257D790004839A/$file/1146+and+1 146+1+June+2014.pdf?OpenElement

, http://yosemite.epa.gov/r9/r9sips.nsf/AgencyProvision/5AD85F69581DEB9388257AC50057D806?OpenDocument

, http://yosemite.epa.gov/r9/r9sips.nsf/AgencyProvision/F65EA6DB0E3F7F06882579210082BE8C?OpenDocument

, and http://yosemite.epa.gov/r9/r9sips.nsf/AgencyProvision/865FFD6DBAC8018F88257E82007BA257/$file/1130+Jun+ 2015.pdf?OpenElement

.

50 We note that 0.02 tpd is about 0.0044 percent of the total V OC 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.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 57 (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 EPA’s current CTG recommendations

. On Jul y 14

, 2015,

EPA approve d the revised SC Rule 1130 as satisf ying 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 th e Attachment to Appendix VI of the 2012 PM 2.5 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 that power

them. As part of its 2007 State Strategy as revised in 20 0 9 and 2011 to support attainment plans

in California for PM 2.5 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 increasin g 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 PM 2.5 and PM 2.5 precursors. For example, in January 2012, CARB adopted the Advanced Clean Car program. 51

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 I V

- C of the 2012 PM 2.5 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 p rovided a justification for measures that were determined to be infeasible for implementation in the South Coast nonattainment area. See 2012 PM 2.5 Plan, Appendix IV

- C.

The inventory for ammonia, provided in Appendix V of the 2012 PM 2.5 Plan, indicates

that the largest sources of ammonia include fuel combustion, waste disposal, miscellaneous sources, industrial sources, livestock, composting, domestic, and on

- road mobile emissions. See

Table D

- 1 (referencing 2012 PM 2.5 Plan at Appendix V, page V

- 4

- 2 ) . T he 2012 PM 2.5 Plan and 2015 Supplement identif

y 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 110 5.1, 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 (ad opted January 10, 2003 ) ; and Rule 1133.3,

Emission Reductions from Greenwaste Composting Operations (adopted July 8, 2011).

51 See 78 FR 2112 (January 9, 2013).TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 58 Table D

- 1 . 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

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 PM 2.5 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 Researc h 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

diff erent components of the CAF operation, such as feeding, milking parlors, housing/bedding, manure management and land application

.

EPA approve d Rule 223 into the SIP o n July 13

, 2015 (see 80 FR 39966 ) . In our technical support document (TSD ) for that rulemaking action, we recommend ed that the District

consider , at its next rulemaking opportunity, control provisions similar to those in SJV Rule 4570 in 2010 ( approved by EPA at 77 FR 2228, January 17, 2012), including lowering the

threshold for rule applicability from 1,000 milk cows to 500 milk cows per facility, and from 650,000 broilers/ducks and layers to 400,000.

 Rule 1105.1, Reductions of PM 10 and Ammonia Emissions from Fluid Catalytic Cracking Units (FCCU), is designed to limit PM 10 and ammonia emissions from fluid catalytic cracking units at oil refineries. The rule sets emission limits for PM 10 and ammonia slip that result from the combination of FCCU emissions and ammonia injection used with electrostatic precipitators (ESP) to c ontrol FCCU emissions. Once in the atmosphere, ammonia emissions react with other compounds to produce secondary PM. The rule requiresTSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 59 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 non

- catalytic reduction, and wet gas scrubbers. 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 amm onia 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, 201 3 (see 78 FR 30768)

.

 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 sea ls), 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 wei ght, 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 reductio n is 70 percent, by weight, for both ammonia and VOC. Rule 1133.2 also specifies required compliance plan elements. 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 of pile is sufficiently we t, 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 pe rcent, by weight, each for VOC and ammonia

emissions. EPA approved this rule into the SIP on November 29, 2012 (see 77 FR 71129).

In addition, for livestock waste, the 2012 PM 2.5 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 technical 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 PM 2.5 Plan, Appendix IV, page IV

- A

- 32). The Supplement states that rule development will follow i f controls are determined to be technically

feasible and cost

- effective. See 2015 Supplement, page F

- 1 and Table F

- 1.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 60 We are proposing to reclassify the So uth Coast from Moderate to Serious nonattainment for the

2006 PM 2.5 standard. A 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), 52 among other things, within 18 months. As part of the District’s development of a BACM control strategy for direct PM 2.5 and those precursors subject to evaluation for potential controls in the South Coast (NO
x , SO 2 , VOC, and ammonia), we encourage the District to consider additional measures previously identified by EPA and the public in comments on the 2012 PM 2.5 Plan, 2015 Supplement, and other individual rules and plans, as well as other potential innovative measures for reducing emiss ions. As part of this process, we suggest that the District consult with other state/local agencies and environmental and industry stakeholders.

Examples of potential rule revisions include:

 lowering the curtailment threshold for Rule 445 (Wood Burning Devices), and further revising Rule 445 by requiring old wood burning stoves be changed out upon home resale, retrofitting wood burning fireplaces with natural gas fireplaces upon major home

rem odeling, and requiring homes that use wood burning as their sole source of heat demonstrate that they maintain a device that meets EPA Phase II emission limits,

 revising Rule 1140 (Abrasive Blasting) to have a 20% opacity limit

,

 expanding coverage of Rul e 1118, Refinery Flares, to include flares at large oil production facilities, similar to San Joaquin Rule 4311

,

 lowering the threshold for rule applicability in Rule 223 from 1,000 milk cows to 500 milk cows per facility, and from 650,000 broilers/ducks and layers to 400,000

, and

 evaluating/encouraging the use of warm

- mix asphalt over hot

- mix asphalt on public and private roads and lots.

Condensable Fraction of Direct PM 2.5 Emissions

EPA’s 2007 PM 2.5 implementation rule state s that “[a]fter January 1, 2011, for purposes of establishing emissions limits under 51.1009 and 51.1010, States must establish such limits taking into consideration the condensable fraction of direct PM 2.5 emissions.” 40 CFR 51.1002(c). The South Coast 2 0 12 AQMP and 2015 Supplement rely on several SIP

- approved rules regulating direct PM emissions as part of the PM 2.5 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 201 5 Supplement,

52 The EP A 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 PM 2.5 nonattainment area unless the State adequately demonstrates that a particular source category does not contribute significantly to nonattainment of the PM 2 .5 standard. See id . At 42011, 42012.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 61 Attachment F, Table F

- 1 and letter dated July 25, 2014 transmitting SC Rule 1155 to EPA

. As part of our action on any rule s that regulate direct PM 2.5 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 requ ires 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. 53 We also note that the SIP

- approved version of Rule 1155 requires measurement of both condensable and filterable PM in 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). 54

3

. Evaluation and Proposed Actio n

We find that t he process followed in the 2012 PM 2.5 Plan and 2015 Supplement to identify RACM/RACT is generally c onsistent with the E PA’s recommendations in the General

Preamble

. The process included compiling a comprehensive list of potential control measures for

sources of direct PM 2.5 , NO
x , VOC, SO 2 , and ammonia in the South Coast . This list i nclud ed

measures suggested in public comments on the Plan

. See 2012 PM 2.5 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 provide d justifications for the rejection of certain identified measure s

. 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 PM 2.5 Plan

, Chapter 4 and Appendices VI, IV

- A, and IV

- C, and 2015 Supplement, Attachment D

. Since submittal of the 2012 PM 2.5 Plan in February 2013, the

District has strengthened, adopted and submitted Rule 1130 , which EPA approved on July 14

, 2015 (see 80 FR 40915 ). Th e EPA ap proved 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

f or these sources is very small

.
We have reviewed the District’s determination in the 2012 PM 2.5 Plan and 2015 Supplement that its stationary and area source control measures represent RACM/ RACT for

direct PM 2.5 , NO
x , VOC, NH 3 and SO 2

. Our rulemaking actions on District rules generally provide the bases for our conclusions that the emission limits and/ or o ther control requirements

in the rule s represent a RAC T level of control , at minimum, for the relevant source categories

. 55

53 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/0/3D4DEB4D21AB4AAF882 570AD005DFF69/$file/SC%20Rest%2 0emiss.pdf).

54 See SCAQMD Test Method 5.1, Determination of Particulate Matter Emissions from Stationary Sources Using a Wet Impingement Train , March 1989 (available at http://aqmd.gov/tao/methods/stm/stm

- 005

- 1.pdf ); SCAQMD Test Method 5.2, Determination of Particulate Matter Emissions from Stationary Sources Using Heated Probe and

Filter , March 1989 (available at http://aqmd.gov/tao/methods/stm/stm

- 005

- 2.pdf ); and SCAQMD Test Method 5.3, Determination of Particulate Matter Emissions from Stationary Sources Using an in

- Stack Filter , October 2005 (available at http://aqmd.gov/tao/methods/stm/stm

- 005

- 3.pdf).

55 A full list of the District’s rules, including citations to our most recent final or proposed rulemaking on each rule can be found in Appendix A to this TSD.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 62 W e also reviewed the potential additional control measures that the District considered

, including those identified by public comment er s during the State/District rulemaking processes

, and believe that the District adequately justified its conclusions with respect to each of these

measures

. Finally, we have reviewed the analysis of current and p otential ly available controls for

both on

- road and off

- road mobile sources in Appendi ces IV

- C and VI, as well as the Attachment to Appendix VI . As we have noted in previous actions on S outh Coast plans

, 56 California is a leader in the development and implementation of stringent control measures for on

- road and off

road mobile sources

. Its current program address es the full range of mobile sources in the S outh

Coast through regulatory programs for both new and in

- use vehicles and through incentive grant

programs. See 2012 PM 2.5 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

- fund ed incentive grants program focused on mobile sources. See 2012

PM 2.5 Plan, Chapter 4

. Overall, we believe that the State, District, and MPO programs provide for the implementation of RACM for emissions of direct PM 2.5 and PM 2.5 precursors from

mobile sources in the S outh Coast

. For the foregoing reasons, w e propos e to find that the 20 12 PM 2.5 Plan and 2015 Supplement provide for the implementation of all RACM/RACT that can be implemented prior to the applicable M oderate 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 PM 2.5 Plan and 2015 Supplement

. 57

56 See the proposed approvals of the South Coast 2007 [8

- hour] Ozone Plan at 76 FR 57872, 5787 9 (September 16, 2011) and the 2007 AQMP addressing the 1997 PM 2.5 NAAQS at 76 FR 41562. 41570 (July 14, 2011).

57 The 2012 PM 2.5 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

PM 10 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 PM 2.5 standards (approved 76 FR 69928 (Nove mber 9, 2011)); the

2007 PM 2.5 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 RA CT demonstration that addressed one or more PM 2.5 precursors.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 63 

### E

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

1. Requirements for Major Stationary Sources of PM 2.5 Precursors

CAA section 189(e) specifically requires that the control requirements applicable to major stationary sources of direct PM 2.5 also apply to major stationary sources of PM 2.5

precursors, exc ept where the Administrator determines that such sources do not contribute significantly to PM 2.5 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 PM 2.5 and PM 2.5 precursors in a Moderate PM 2.5 nonattainment area include, at minimum, the requirements of a nonattainment new source review (NNSR) permit program meeting the requirements of CAA section 172(c)(5) ( see CAA 189(a)(1)(A))

.

2

. Evaluation of Major Source Control Requirements in the 2012 PM 2.5 Plan and 2015 Supplement

In Attachment E to the 2015 Supplement, the District address ed the NNSR control requirements that apply to major stationary sources of direct PM 2.5 and PM 2.5 precursors in the

S outh Coast nonattainment area.

3. Evaluation and Proposed Action

I n a separate rulemaking to approve revisions to SCAQMD’s NNSR permit program

, EPA evaluated the District’s discussion of con trol requirements applica ble to major stationary

sources ( Attachment E of the 2015 Supplement ) and determined that the District’s SIP

- approved

N NSR program satisfies the requirements of CAA section 189(e) for direct PM 2.5 and all PM 2.5

precursors

. 58 Accordingly, in this action, EPA is not addressing the NNSR con trol requirements that apply to major stationary sources of direct PM 2.5 and PM 2.5 precursors in the South Coast

area under CAA section 189(e)

.

58 See n. 27, supra.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 64 

### F

. Adopted Control Strategy

1. Requirements for Control Strategies

CAA section 1 10 ( 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

requ irements of the Act. ” Section 172(c)(6) of the Act, which applies to nonattainment area SIPs, is virtually identical to section 1 10 ( a )( 2 ) (A). 59 Measures necessary to meet RACM/RACT and the additional control requirements under section 172(c)(6) must be adop ted 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 sect ions 113 and 304 , respectively

. In the past, the EPA has approved enforceable commitments and courts have enforced actions against state s that failed to comply with them

. 60 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 address a limited port ion of

the CAA

- required program; (b) is the state cap able of fulfilling its commitment; and (c) is the commitment for a reasonable and appropriate period of time. 61

2

. Control Strategy in the S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement

For purposes of evaluating the S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement

, we have divide d 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, S tate, and D istrict r ules and regulations adopted prior to June 2012 for District rules and prior to August 2011 for CARB

rules (i.e., prior to the development of the 20 12 PM 2.5 Plan) that continue to achieve emissions

59 The language in sections 110(a)(2)(A) and 172(c)(6) is quite broad, allowing a SIP to contain any enforceable “means or techniques” that EPA determines are “necessary or a ppropriate” 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 req uired controls might not have to be in place when a SIP is approved.

60 See , 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).

61 Courts hav e upheld EPA’s use of this “three

- factor test” to ensure that a state’s use of such commitments is a limited component of a comprehensive strategy for attaining the NAAQS. See BCCA Appeal Group v. EPA, 355 F.3d 817 (5th Cir. 2003), reh’g denied, 2004 U.S. App. LEXIS 215 (5th Cir., January 8, 2004) and Environmental Defense v. EPA , 369 F.3d 193 (2d Cir. 2004).TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 65 reductions t hrough the current a ttainment year of 201 5 and beyond

. 62 The Plan describes many of these measures in Chapter 4 and in Appendices III, IV

- A

, IV

- C, and VI

. Reductions from

these baseline measures are incorporated into the baseline inventory and reductions from the

District measures in particular are quantified in Appendix III, Table III

- 2

- 2B

. According to the Plan, t hese measures provide most of the emissions reductions projected to occur between the base year of 2008 and the Moderate area attainment date of 2015 and, based on the model

predicted lev el of emission reductions needed to meet the 2006 PM 2.5 sta ndard in the S outh Coast, the majority of the reductions needed to meet that standard. See 2012 PM 2.5 Plan , Chapter 4 and Appendix V and 2015 Supplement, Attachment A

. According to the Plan, t hese measures provide most the emissions reductions projected to

occur between the base year of 200 8 and the modeled attainment year of 2015

. See 2012 PM 2.5 Plan , Chapter 4 and Appendix V and 2015 Supplement, Attachment A

.

Control strategy measures are the new rules, rule revisions, commitments and other

measures that provide the additional increment of emission s reductions needed beyond the

baseline measures to provide for attainment, to demonstrat e RFP, to meet the RACM/RACT requirement, or to provide for contingency measures. We discuss the control strategy measures

and commitments in this section . District b aseline measures are listed in Appendi x A of this

TSD.

T he District included several new measures in the 2012 PM 2.5 Plan and 2015 Supplement

to provid e for attain ment of the 2006 PM 2.5 NAAQS

. First , the District committed to adopt, submit, and implement amendments to two District rules (Rule 444 and Rule 445) to reduce

direct PM 2.5 emissions from open burning and residential wood burning activities

. See 2012

PM 2.5 Plan, p. 4

- 8 , Table 4

- 2 and S CAQMD 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, t he District committed to achie ve 1 1. 7 tpd of direct

PM 2.5 emission reductions by 201 5

, either from these two amended rules or from substitute measures as necessary to address any shortfall in emission reductions

. I d

. Third , the District committed to carry out technology assessment s 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 201 5

, as a contingency measure , and to adopt backstop me asures related to ports and port

- related f acilities in 2015

. Id

. Following the State’s submittal of the

2012 PM 2.5 Plan to 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 EPA for SIP approval, consistent

with its commitments in the Plan. All of t hese measures and commitments are listed in Table F

- 1

below.

62 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).TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 66 Table F

- 1 . SCAQMD 2012 PM 2.5 Plan and 2015 Supplement Specific Rule

Commitments

District Rule

Number Measure Number & Description Adoption

Date Implementati

on Date Emission

Reductions

444 Further Reductions from Open

Burning 63 2013 May 3, 2013 4.6 tpd PM2.5

445 Further Reductions from Residential

Wood Burning 64 2013 May 3, 2013 7.1 tpd PM2.5

1138 Emissions Reductions from Under

fired Charbroilers 2017 N/A TBD

1127 Further Ammonia Emissions From

Livestock Waste 2015

- 2016

Technology

Assessment N/A TBD

2002 Further NOx Reductions from

RECLAIM 2015 N/A 2 tpd NOx

4001 Backstop Measures for Indirect Sources

of Emissions from Ports and Port

related Facilities 2015 N/A N/A

Source: 20 12 PM 2.5 Plan, Chapter 4, Table 4

- 2

, as amended by 2015 Supplement, Attachment F, Table F

- 1.

3

. Evaluation and Conclusion s

T he Plan provides for the majority of the emission s reductions ne cessary for attainment

to be achieved from baseline measures . These reductions come from a combination of District

, State and federal stationary and mobile source measures. 65 Over the past four decades, the

District has adopted or revised almost 100 prohibitory rules that limit emissions of NO
x , SO 2

, ammonia, VOC

, and particulate matter from stationary sources

. See Appendix A of this TSD. The vast majority of these rule s 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 PM 2.5 emissions. California has als o adopted standards for many categories of on

- and 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 o btain a waiver of federal pre

- emption under CAA section 209

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

64 Ibid.

65 These federal measures include EPA’s national emissions standards for heavy duty diesel trucks (66 FR 50 01 (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.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 67 (“section 209 waiver measure s ” or “waiver measure s ”) and those for which the State is not required to obtain a waiver (“non

- waiver measure s ” or “SIP measures” ).

Under the Clean Air Act, the EPA i s 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 (refe rred to herein as “waiver measures”). Over the years, the EPA has issued waivers or authorizations for many mobile source regulations adopted by CARB. California attainment and maintenance plans rely on emissions reductions from implementation of the

waive r measures through use of emissions models such as EMFAC, and the South Coast 2012

PM 2.5 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 r egulations) 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 the EPA’s longstanding practice in this regard was at odds with the CAA requirement that state and loca l emissions limits relied upon to meet the NAAQS be

enforceable by EPA or private citizens through adoption and approval of such limits in the SIP. 66

In response to the court’s decision, CARB has adopt ed the necessary waiver measures as

revisions to the California SIP and submitt ed them to EPA for approval. 67 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. I n today’s action, the EPA is proposing to approve certain elements of the 2012 PM 2.5 Plan and 2015 Supplement in part based on our expectation 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.

As disc ussed 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 PM 2.5 Plan and 2015 Supplement do not rely on either the rule amendment

commitm ents or the emission reduction commitments in its impracticability demonstration, RACM demonstration, RFP demonstration, or quantitative milestones, or to meet any other CAA requirement

. T herefore, we do not need to apply this three

- factor test before prop osing 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 [PM 2.5 NAAQS] and achieving expedit ious attainment of such standards.” See CAA 176(c)(1)(A).

W e 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 i n Attachment F of the 2015 Supplement ), and to achieve specified NO
x emission reductions

, to the extent that these commitme nts have not yet been fulfilled

.

66 See Committee for a Better Arvin v. EPA

, 786 F.3d 1169 (9th Cir. 2015).

67 See lette r dated August 14, 2015, from Richard W. Corey, Executive Officer, California Air Resources Board, to Jared Blumenfeld, Regional Administrator, EPA Region 9.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 68 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 measure s to achieve an additional 2 tpd of NOx emission

reductions in 2015 , and 4) adopt backstop m easures for indirect sources of e mi ssions from ports and port

- related f

acilities

. See 2012 PM 2.5 Plan, p. 4

- 8, Table 4

- 2 and SCAQMD Governing

Board Resolution 12

- 19 (Dec. 7, 2012) , p p

. 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 PM 2.5 emission reductions , the District has satis fied these commitments by submitt ing the fully adopted rules to EPA on June 11, 2013

, together with technical documentation to support its conclusion that these rules will achieve 11.7 tpd of direct PM 2.5 emission reductions in 2015. 68
EPA approved Rule 444 and Rule 445 on September 26, 2013 (see 79 FR 59249 ). 69

68 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.

69 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.TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 69 

### G. Demonstration that Attainment by the Moderate Area Attainment Date is Impracticable

1. Requirements for Attainment/Impracticability of Attainment Demonstrations

CAA s ection 189(a) (1)(B) require s that each Moderate area attainment plan include a

demonstration that the plan provides for attainment by the latest applicable Moderate area

deadline or, a lternatively, t hat attainment by the latest applicable attainment date i s im practicable . A demonstra tion 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

1 3538). 70

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 PM 2.5 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 RAC M/RACT to existing sources. The EPA believes i t 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 und er 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.

2. Impracticability Demonstration for th e 2012 PM 2.5 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 PM 2.5 NAAQS. The letter provided preliminary 2015 air quality monitoring data for the Mi ra Loma monitoring station supporting a conclusion that

attainment of the 2006 PM 2.5 standard by December 31, 2015 in the South Coast is impracticable. 71

Based in part on the information contained in this letter and in the 2012 PM 2.5 Plan and Supplement, we have conducted an analysis of recent PM 2.5 monitoring data for the South Coast

PM 2.5 nonattainment area. 72 For this analysis, the EPA use d certified data for 2013, 2014 and

70 For more information on the applicable air quality modeling requirements, please see section II.B of the TSD.

71 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.

72 Se e 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”).TSD for the Proposed Action

S outh Coast 20 12 PM 2.5 Plan and 2015 Supplement September 2015

EPA

- Region 9 Page 70 preliminary data available for 2015. 73 Although the State and District originally in tended for the

2012 PM 2.5 Plan and 2015 Supplement to demonstrate that the area would attain the 2006 PM 2.5 NAAQS by the Moderate area attainment date of December 31, 2015, more recent monitoring

data show that 24

- hour PM 2.5 levels in the South Coast, with a current design value (2012

- 2014) of 38 μg/m 3 at the Mira Loma monitoring site, continue to be above the 35 μg/m 3 level of the

2006 PM 2.5 standard, and the recent trends in the South Coast’s 24

- hour PM 2.5 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 98 th percentile. If the estimated 2015 98 th

perc entile was greater than the maximum allowed 2015 98 th percentile concentration, the EPA considered attainment at that monitoring site impracticable. For each monitor, the EPA

estimated the 2015 98 th percentile from the 2015 data available in AQS as of Aug ust 2015, based a number of assumptions. 74 The EPA assumed that the concentrations measured during the remainder of 2015 would be no higher than those already recorded, so the 98 th 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 98 th percentiles could be higher than recorded values.

The EPA’s analysis showed that during 2015, two monitoring sites (Rubidoux and Mira

Loma

- Van B uren) had estimated 98 th percentiles greater than the maximum allowed 98 th
percentile concentration for 2015, which indicates that attainment of the 2006 24

- hour PM 2.5 NAAQS by the end of 2015 is impracticable.

In a separate analysis, EPA assumed that Rubi doux 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 8 th highest recorded value as the 98 th percentile for 2015. This assumption resulted in selection of the lowest 98 th 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 98 th percentiles greater than the

ma ximum allowed 2015 98 th percentile.

73 Some d ata in the 2 nd , 3 rd , and 4 th 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 compl etely 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.

74 EPA also assumed that the sampling rate obser ved 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 98 th percentile in accordance with 40 CF R part 50, appendix N, section 4.5.TSD for the Proposed Action

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- Region 9 Page 71 3. Evaluation and Proposed Action

Our conservative assessment of recent PM 2.5 air quality data indicates that attainment of

the 2006 PM 2.5 standard in the South Coast by December 31, 2015 is impracticable. We have

also evaluated the RACM/RACT demonstration in the 2012 PM 2.5 Plan and 2015 Supplement and find that it provides for the expeditious implementation of all RACM that may feasibly be implemented at this time, consistent with the requirements of CAA sections 172(c) (1) and 189(a)(1)(C) for the 2006 PM 2.5 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 th is evaluation , we propose to approve the State’s demonstration in the 2012

PM 2.5 Plan and 2015 Supplement that attainment of the 2006 PM 2.5 standard by the Moderate area attainment date in the South Coast is impracticable, consistent with the require ments 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 an d 4 of part D, Title I of the Act (see Section III of this TSD).TSD for the Proposed Action

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### 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 section 189(c) requires PM 2.5 nonattainment area SIP s

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 1 of the Act requires that a set percentage of emissions reducti ons 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)

. A s discussed in the EPA’s guidance in the Addendum

, r equiring linear progress in reductions of direct PM 2.5 and any individual precursor in a PM 2.5 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 P M 2.5 levels over the standard ) , and/or

 the emission reductions ne cessary to attain the PM 2.5 standard are inventory

- wide. Id

.

T he EPA’s guidance in the Addendum at 42105 recommends that requiring linear progress is less appropriate in other situations

, such as :

 w here there is a limited number of sources of direc t PM 2.5 or a precursor
,

 w here the relationships between individual sources and air quality are relatively well

defined , and/or

 w here 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

s oon 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 em ission reductions of

direct PM 2.5 or a PM 2.5 precursor .” (Addendum at 42015.)

Plans for PM 2.5 nonattainment areas should include detailed schedules for compliance with emission regulations in the area and provide corr esponding annual emission reductions to

be realized from each milestone in the schedule (Addendum at 42016). In reviewing anTSD for the Proposed Action

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- Region 9 Page 73 attainment plan under subpart 4, the EPA 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 complia nce 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 the state demonstrates compliance with the quantitative milestone requirement, i t will demonstrate that RFP has been achieved during each of the relevant 3 years. Quantitative milestones should consist of elements that allow progress

toward attainment to be quantified or measured. Specifically, states should identify and submit quantitative milestones providing for the amount of emissions reductions adequate to achieve the NAAQs by the applicable attainment date ( see 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.

2. RFP Demonstration and Quantitative Milestones in the 20 12 PM 2.5 Plan and 2015 Supplement

South Coast’s 2012 PM 2.5 Plan was originally developed in accordance with the requirements of subpart 1 and the 2007 PM 2.5 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 PM 2.5 Plan as originally adopted (in December 2012) included the Sta te’s

demonstration of attainment by December 14, 2014 , which is five years from the date of designation, 75 the Plan does not include a separate RFP demonstration

.

Following the D.C. Circuit’s January 2013 decision remanding the 2007 PM 2.5 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 PM 2.5 NAAQS . By the time the 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 PM 2.5 standard.

75 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 y ears 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.TSD for the Proposed Action

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- Region 9 Page 74 See 2015 Supplement, p. 4

. Accordingly, the 2015 Supplement does not contain a separate RFP or quantit ative milestone demonstration

.

3

. Evaluation and Proposed Action

As a result of the NRDC decision remanding the 2007 PM 2.5 Implement ation Rule

, the

EPA has considered whether the 2012 PM 2.5 Plan and 2015 Supplement meet the RFP requirement in section 172(c)(2) of the Act and pr oposes to find that they do

.

The 2012 PM 2.5 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. 76 The

Plan also shows steady reductions in direct PM 2.5 , NOx, VOC, SOx, and ammonia emissions during the 2008

- 2014 period

. Figure s II H

- 1 and II H

- 2 show the emissions trajectories for direct

PM 2.5 and each PM 2.5 precursor addressed in the control strategy which indicate generally linear

reductions

. We propose, therefore, to approve the 2012 PM 2.5 Plan and 2015 Supplement as satisfying the requirement for RFP in CAA section 172(c) (2) for the 2006 PM 2.5 standard.

With respect to quantitative milestones, t he 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 PM 2.5 standard in the South Coast. This date is the due date for the State’s submittal of attainment

related SIPs nec essary to satisfy the Moderate area requirements applicable to the South Coast

area. 77 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 af ter 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 th is proposal to reclassify the South Coast area as Serious

nonattainment for the 2006 PM 2.5 standard or determines that the area has failed to 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.

76 See 2012 PM 2.5 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”)

.

77 Subpa rt 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 PM 2.5 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).TSD for the Proposed Action

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- Region 9 Page 75 Source for Figures II H

- 1 and II H

- 2 : 2012 AQMP, Chapter 3, Tables 3

- 2A, 3

- 4A, Appendix III, Table III

- 1

- 5 , and 2008 ammonia inventory from Appendix V, Table V

- 4

- 2.

0 100 200 300 400 500 600 700 800

2008 2014 tons per day (tpd)

year 

### Figure IIH

- 1. Reduction in Overall NOx and VOC Emissions,

2008

- 2014

NOx VOC

0 20 40 60 80 100 120

2008 2014 tons per day (tpd)

year 

### Figure IIH

- 2. Reduction in Overall PM2.5, SOx, and Ammonia

Emissions, 2008

- 2014

PM2.5 SOx NH3TSD for the Proposed Action

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### I

. Contingency Measures

1. Requirement s for Contingency Measures

Under CAA section 172(c)(9), PM 2.5 plans must include contingency measures to be implemented if an area fails to meet RFP ( “ RFP contingency measures ” ) or fails to attain the

PM 2.5 NAAQS 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 particu late 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 the SIP includes a demonstration that attainment by the appl icable attainment date is impracticable, the state need only submit contingency measures to be implemented if an area fails to meet RFP. 78

Th e purpose of contingency measures is to continue progress in reducing emissions while

the SIP is being revised to me et the missed RFP milestone or to provide for attainment

.
The princip al requirements and recommendations for contingency measures are:

 Contingency measures must be fully adopted rules or control measures that are ready to be implemented quickly upon failu re 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 fur ther action by the state or by the EPA

. In general, we expect all actions needed to e ffect full implementation of the measures to occur within 60 days after the EPA notifies the state of a failure.

 C ontingency measures should consist o f control measures for the area that are not

relied on to demonstrate attainment or RFP.

 The measures should provide for emission s reductions equivalent to approximately one year of reductions needed for RFP calculated as the overall

level of reductions ne eded to demonstrate attainment divided by the number of years from the base year to the attainment year

.

See General Preamble at 135 43 and Addendum at 42014.

2

. Contingency Measures in the 2012 PM 2.5 Plan and 2015 Supplement

Contingency measures for failure to attain are described in Chapter 6, pages 6

- 7 to 6

- 13

of the 2012 PM 2.5 Plan. The 2012 PM 2.5 Plan and 2015 Supplement do not include contingency

measures for failure to meet RFP.

78 The EPA does not interpret the requirement for failure

- to

- attain contingency measures to apply to Moderate PM 2.5 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).TSD for the Proposed Action

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- Region 9 Page 77 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 t o attain are not required as part of this Moderate area plan. Upon reclassification of the South Coast 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 PM 2 .5 NAAQS.

W e 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 PM 2.5 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 me asures in the South Coast and to revise the

2012 PM 2.5 Plan to assure that it still provided for attainment by the applicable attainment date of December 31, 2015. In this case, however, the 2012 PM 2.5 Plan and 2015 Supplement

demonstrate that actua l emiss ion 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, an d therefore EPA proposes to find that the requirement for them is now moot.TSD for the Proposed Action

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### J

. Motor Vehicle Emissions Budgets

1. Requirements for Motor Vehicle Emissions Budgets

CAA section 176(c) requi res 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 viol ations 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 a re 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, EPA, FHWA, and FTA to demon strate that an area’s RTP and transportation improvement programs (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. B udgets are generally 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 de monstrations (40 CFR § 93.118(e)(4)(v)).

PM 2.5 plans should identify motor vehicle emission budgets for direct PM 2.5 and all significant PM 2.5 precursors for each RFP milestone year and the attainment year, if the plan

demonstrates attainment . All direct PM 2.5 SIP budgets should include direct PM 2.5 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 PM 2.5 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 PM 2.5 Plan and 2015 Supplement

The 2015 Supplement revised the attainment demonstra tion in the 2012 PM 2.5 Plan to identify December 31, 2015 as the applicable attainment date, and included revised budgets for 2015 for directly emitted PM 2.5 , NOx, and VOC. See 20 15 Supplement, Attachment C, Table C

1. These budgets reflect average annual daily emissions and are calculated using 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 PM 2.5 budgets included tailpipe, brake wear, and tire wear emissions as well as paved and unpaved road dust and r oad construction dust

. No budgets for SO 2 were included inTSD for the Proposed Action

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- Region 9 Page 79 the 2012 PM 2.5 Plan or 2015 Supplement because on

- road emissions of SO 2 are a small part (1 1 percent) of the total SO 2 inventory

. No budgets for a mmonia were included in the 2012 PM 2.5 Plan or 2015 Supplement

.

3. Conclusion and Proposed Actions

We are not acting on the motor vehicle emission budgets for direct PM 2.5 , NOx, and VOC

in the 2012 PM 2.5 Plan or 2015 Supplement. We have previously approved motor vehicle emissions budgets for the 1997 annual and 24

- hour PM 2.5 standards ( 76 FR 69 928 , 699 51 (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 PM 2.5 standard until we finalize our approval of new budgets in the Serious area plan for the 2006 PM 2.5 NAAQS or find th ose budgets adequate. The budgets approved in 2011 will continue to apply in the S outh Coast for determining transportation

confo rmity for the 1997 PM 2.5 annual and 24

- hour standards. 79

79 In 2012, the EPA revised the annual PM 2.5 standard, lowering its leve l from 15 μg/m 3 to 12 μg/m 3 (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 PM 2.5 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 r evocation of such NAAQS

.TSD for the Proposed Action

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- Region 9 Page 81 

### K . 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 1 76(c)(4) of the CAA establishes the framework for g eneral conformit y. The EPA first promulgated general conformity 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 c onformity 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 dete rminations, and allows for air quality

review of individual federal actions.

The general conformity regulations provide three phases: (A) applicability analysis, (B) conformity determination, and (C) review process. The applicability analysis phase under 4 0

CFR § 93.153 is used to determine whether 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 tha t 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.

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 they 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 circumstan ces.

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 emission budget, may be used by federal agencies to demonstrate conformity as l ong as the total facility

- wide budget level identified in the SIP is not

exceeded.TSD for the Proposed Action

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- Region 9 Page 82 According to 40 CFR 93.161, the state or local agency responsible for implementing and enforcing the SIP can develop and adopt a n emissions budget to be used for demonstrati ng 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 t o 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 agency from demonstrating conformity in any other manner allowed by the conformity rule.

2. General Conf

ormity Budget in the 2012 PM 2.5 Plan and 2015 Supplement

The 2012 PM 2.5 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 V OC and NOx because of its designation and classification as a severe ozone nonattainment area, and 100 tpy of PM 2.5 because of its designation and classification as a

moderate PM 2.5 nonattainment area. 80 The District examined historical records and noted th at projects requiring general conformity determinations had historically not exceeded the PM 2.5 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 tracki ng system that the District sets up for projects subject to general conformity determinations . The District will count project emissions towards the applicable general conformity budget until the budget has been used. Any unused portions will not carry forward from year to year. Once the budget is used, federal projects can still

demonstration con formity using other provisions in the conformity rule. And 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 poll utants or

precursors.

3. Evaluation and Proposed Action

We propose to approve the general conformity budgets in the 2012 PM 2.5 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 S tate and District

80 Final reclassification of the South Coast area as Serious nonattainment for the 2006 PM 2.5 standard may 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 PM 2.5 and PM 2.5 precursors. See 80 FR 15339 at 15441; see also Section III of this TSD.TSD for the Proposed Action

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- Region 9 Page 83 confirm ing that the project ’s 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 exhausted, future federal projects will need to demonstrate conformity using a different method.TSD for the Proposed Action

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- Region 9 Page 84 

## II I

. Proposed Recl assification as Serious Nonattainment and

Serious Area SIP RequirementsTSD

- Proposed Approval

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### A. Proposed Reclassification as Serious and Applicable Attain ment Date

Section 188 of the Act outlines the process for classification of PM 2.5 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 re classify 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 additio n, subparagraphs (A) and (B) of section 188(b)(1)

mandate that the EPA reclassify “appropriate” PM 10 nonattainment areas at specified time frames ( i.e., by December 31, 1991 for the initial PM 10 nonattainment areas, and within 18 months after

the SIP submi ttal 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. 81

We have reviewed recent PM 2.5 monitoring data for the South C oast available in the EPA’s Air Quality System (AQS) database. These data show that 24

- hour PM 2.5 levels in the

South Coast continue to be above 35 μg/m 3 , the level of the 2006 PM 2.5 standard, and the recent

trends in the South Coast’s 24

- hour PM 2.5 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

S outh Coast area from Moderate to Serious nonattainment for the 2006 24

- hour PM 2.5 standard

of 35 μg/m 3 , based on the EPA’s determination that the S outh Coast area cannot practicably

attain this standard by the applicabl e attainment date of December 31, 2015

.

81 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 a t 13537

- 38 (April 16, 1992).TSD for the Proposed Rulemaking on the

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- Region 9 Page 86 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 S outh Coast area was designated nonattainment for

the 2006 PM 2.5 standard effective December 14, 2009. 82 Therefore, upon final re classification of

the S outh Coast area as a Serious nonattainment area, the latest permissible attainment date under section 188(c)(2) of the Act, for purposes of the 2006 PM 2.5 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 EPA may grant if the State satisfies certain conditions. Before EPA may extend the attainment date for a Serious area under section 188(e), th e 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 t he 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. 83



### B. Clean Air Act Requirements for Serious PM 2.5 

### Nonattainment Area Plan s

Upon reclassification as a Serious nonattainment area for the 2006 PM 2.5 NAAQS, California will be required to submit additional SIP revisions to satisfy the statutory requirements that apply to Serious PM 2.5 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 cont rol of direct PM 2.5 and PM 2.5 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 provide s 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 alternative date practicable and no later than December 31, 2024 (CAA sections 188(c)(2) and 189(b)(1)(A));

82 See 74 FR 58688 (November 13, 2009).

83 For a discussion of EPA’s interpretation of the requirements of section 188(e), see “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) (hereafter “Addendum”) at 42002; 65 FR 19964 (April 13, 2000) (proposed action on

PM 1 0 Plan for Maricopa County, Arizona); 66 FR 50252 (October 2, 2001) (proposed action on PM 10 Plan for Maricopa County, Arizona); 67 FR 48718 (July 25, 2002) (final action on PM 10 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 PM 10 Plan for Maricopa County, Arizona but generally upholding EPA’s interpretation of CAA section 188(e)).TSD for the Proposed Rulemaking on the

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- Region 9 Page 87 3. plan provisions that require reasonable further progress (RFP) (CAA 172(c)(2));

4. quantitative m ilestones which are to be achieved every 3 years until the area is redesignated

attainment and which demonstrat e RFP toward attainment by the applicable date (CAA section 189(c));

5. p rovisions to assure that control requirements applicable to major stationa ry sources of

PM 2.5 also apply to major stationary sources of PM 2.5 precursor s, except where the s tate
demonstrates to the EPA’s satisfaction that such sources do not contribute significantly to

PM 2.5 levels that exceed the standa r d in the area (CAA sectio n 189(e));

6. a comprehensive, accurate, current inventory of actual emissions from all sources of PM 2.5 and PM 2.5 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 applica ble attainment date (CAA section 172(c)( 9 )) ; and

8. A revision to the nonattainment new source review ( N NSR) program to lower the applicable “major stationary source” 84 threshold s 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 PM 2.5 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 PM 2.5 and PM 2 .5 precursors. See 80 FR 15339 at 15441.

The EPA recently 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 PM 2.5

. 85 In the interim

, before the PM 2. 5 implementation rule is

finalized , 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

S outh Coast PM 2.5 nonattainment area. 86



### 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.

I f a final reclassification of the South Coast PM 2.5 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

84 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 PM 10 (CAA sections 189(b)(3)).

85 See 80 FR 15339, “Fine Particulate Matter National Ambient Air Quality Standards: State Implementation Plan Requirements,” March 23, 201 5.

86 See generally the General Preamble, 57 FR 13498 (April 16, 1992) and Addendum, 59 FR 41998 (August 16, 1994).TSD for the Proposed Rulemaking on the

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- Region 9 Page 88 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 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 option al precursor insignificance demonstration to support a determination to exclude a PM 2.5 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

- mo nth 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. 87

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 attainment

- related 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 requi red under section 189(c); (3) any 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.

Th e EPA designated the South Coast area as nonattainment for the 2006 PM 2.5 standard effective December 14, 2009. 88 On January 4, 2013, the D.C. Circuit Court of Appeals issued its

decision in NRDC remanding EPA’s 2007 PM 2.5 Implementation Rule and directing the EPA to repromulgate it in accordance with the requirements of subpart 4. 89 In response to the NRDC decision, the EPA undertook a rulemaking to classify all PM 2.5 nonattainment areas as Moderate nonattainment and begin implementing the PM 2.5 NAAQS unde r subpart 4. Effective July 2, 2014, the EPA classified all areas previously designated nonattainment for the 1997 and/or 2006 PM 2.5 NAAQS as Moderate nonattainment under subpart 4 and established a December 31, 2014 deadline for states to submit Moderate area SIP elements required for these areas. 90 These unusual circumstances have significantly shortened the timeframes ordinarily all owed under the Act for the

87 Section 172(b) requires 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.

88 74 FR 58688 (November 13, 2009).

89 NRDC v. EPA , 706 F.3d 428 (D.C. Cir. 2013).

90 79 FR 31566 (June 2, 2014). 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 deadli ne provided the opportunity for states to revise or supplement their prior submissions, as necessary or appropriate to meet subpart 4 requirements.TSD for the Proposed Rulemaking on the

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- Region 9 Page 89 EPA and the states to address the statutory SIP requirements following reclassification of an area from Moderate to Serious nonattainment under subpart 4. 91

Our proposal to require the State to submit the attainment demonstratio n 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 Moder ate area attainment date. Under normal circumstances, where the EPA reclassifies an area within 3 years after its designation as nonattainment, as contemplated in CAA section 188(b)(1)(B), 92 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). 93 In these circumstances, the Ser ious area attainment demonstration would be due at least 3 years before the outermost Serious area attainment date for the area, 94 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 Serio us area attainment date applicable to the area in setting a deadline for the State to submit the required elements of the Serious area attainment plan.

Upon reclassification as Serious, the South Coast PM 2.5 nonattainment area will be subject

to a Serio us area attainment date no later than December 31, 2019. 95 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 PM 2.5 standard by this date, including quantitative milestones w hich 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 y ears following reclassification ( i.e., potentially until early 2020) to submit the attainment demonstration and related plan elements, these Serious area plan

91 For areas designated nonattainment after November 15, 1990, section 188(b)(1)(B) of the Act requires that 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 nona ttainment 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 Se rious 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).

92 Id

.

93 CAA sectio n 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 6 th 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.

94 Under CAA section 188(c)(2), th e latest permissible attainment date for a Serious PM 2.5 nonattainment area is no later than the end of the tenth calendar year beginning after the area’s designation as nonattainment.

95 Id.TSD for the Proposed Rulemaking on the

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- Region 9 Page 90 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 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

- rel ated 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 N SR 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 PM 2.5 precursors (CAA section 189(e)) 96 following reclassification of a Moderate PM 2.5 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 pr oposes 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 PM 2.5 precursors, no later than 18 months after the effective date of fina l

reclassification of the South Coast area as Serious nonattainment for the 2006 PM 2.5 standard. This due date will ensure that necessary control requirements for major sources are established well in advance of the required attainment demonstration. An 1 8

- month timeframe for submission of the

N NSR SIP revisions also aligns with the statutory deadline for submission of BACM and BACT provisions and the broader analysis of PM 2.5 precursors for potential controls on existing sources in

the area.

96 Section 189(e) requires that the control requirements applicabl e to major stationary sources of PM 2.5 also apply to major stationary sources of PM 2.5 precursors, except where the state demonstrates to EPA’s satisfaction that such sources do not contribute significantly to PM 2.5 levels that exceed the standard in the a rea.TSD for the Proposed Rulemaking on the

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### D. R eclassification of Reservation Areas of Indian Country 97

Seven Indian tribes are loca ted within the boundaries of the South Coast PM 2.5 nonattainment area. These tribes are listed in Table III

- 2 below.

Table III

- 2. Indian Tribes Located in South Coast PM 2.5 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 B and of Luiseno Indians

We have considered the relevance of our proposal to reclassify the S outh Coast area as Serious nonattainment for the 2006 PM 2.5 standard to each tribe located within the S outh Coast

area. We believe that the same facts and circumstances that support the proposal for the non

- Indian country lands also support t he proposal for reservation areas of Indian country and any other area of Indian country where the EPA or a tribe has demonstrate d that the tribe has jurisdiction located

within the S outh Coast nonattainment area. The EPA is therefore proposing to exercise our authority under CAA section 188(b)(1) to reclassify areas of Indian country geographically located

in the S outh 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 att ainment date.

Directly

- emitted PM 2.5 and its precursor pollutants (NO
x , SO 2 , 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 approa ch best ensures public health protection from the adverse effects of PM 2.5 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 with in the S outh Coast PM 2.5

97 “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 runni ng 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 allotme nts, the Indian titles to which have not been extinguished, including rights

- of

- way running through the same.”TSD for the Proposed Rulemaking on the

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- Region 9 Page 92 nonattainment area. Moreover, violations of the 2006 PM 2.5 standard, which are measured and modeled throughout the nonattainment area, as well as shared meteorological conditions, would

dictate the same conclusion . Furthermore, emissions increases in portions of a PM 2.5 nonattainment

area that are left classified as Moderate could counteract the effects of efforts to attain the standard

within th e overall area because less stringent requirements would apply in those Moderate portions

relative to those that would apply in the portions of the area re classifi ed to Serious

. Uniformity of classification throughout a nonattainment area is thus a guiding principle and premise when an area is being reclassified. Equally, i f the EPA believes i t is likely that a given

nonattainment area will not attain the PM 2.5 standard by the app licable 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 demonstra ted 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 S outh Coast nonattainment are a cannot practicably

attain the 2006 PM 2.5 standard by its applicable Moderate area attainment date of December 31,

2015.

I n light of the considerations outlined above that support retention of a uniformly

- classified

PM 2.5 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 PM 2.5 standard.

T he 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 f rom its current level of 100 tpy to 70 tpy (CAA section s 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 Conf ormity r equirements

, 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 agenci es for projects in these areas of Indian country may be more difficult to

ob tain because of the lower de minimis thresholds.

Given the potential implications of the reclassification

, the EPA has contact ed tribal

officials to invite government

- to

- government consultation on th is rulemaking effort. 98 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 program s under the CAA, none of the affected tribes will be required to submit an implementation plan to address th is

reclassification.

98 We sent letters to seven tribal officials regarding government

- to

- government consultation on September 4, 2015 and September 30, 2015

.