2318 Federal Register / Vol. 86, No. 7 / Tuesday, January 12, 2021 / Proposed Rules 

quotations on the Expert Market? Where 

possible, please provide data or identify 

sources of information the Commission 

could use to analyze the impact of the 

relief on liquidity and price discovery. 

6. Does the proposed policies and 

procedures condition provide 

appropriate assurance that real-time and 

delayed quotations published or 

submitted on the Expert Market would 

not be accessible to the general public, 

including retail investors, other than the 

Qualified Experts? Please explain why 

or why not. If not, please explain how 

the condition should be modified, 

including the minimum requirements 

that should be included in OTC Link’s 

policies and procedures to (1) ensure 

that only Qualified Experts can view 

quotations published or submitted on 

the Expert Market and (2) address 

concerns about fraud and manipulation? 

7. Does the proposed recordkeeping 

condition for OTC Link LLC provide 

appropriate means to facilitate the 

Commission’s oversight of the Expert 

Market, including of Subscribers that 

publish or submit quotations on the 

Expert Market and the distribution of 

such quotations? Please explain why or 

why not. If not, please explain how the 

condition should be modified. 

8. Are the proposed safeguards 

appropriate to ensure that only investors 

who are able to assess the risks and 

merits of investment in the categories of 

securities proposed to be included in 

the Expert Market are able to access 

quotations? Are the proposed conditions 

of this exemptive order (in conjunction 

with FINRA rules that govern this 

market) sufficient to prevent the general 

public from accessing quotations 

published or submitted in the Expert 

Market, or should the Commission 

impose additional conditions? Are there 

any other safeguards that should be 

implemented in the Expert Market to 

protect investors? 

9. Are there additional conditions that 

the exemptive order providing the relief 

proposed herein should include to help 

prevent persons who are not Qualified 

Experts from accessing quotations 

published or submitted on the Expert 

Market? If yes, please specify such 

condition and explain how this 

suggestion would be necessary or 

appropriate in the public interest and 

consistent with the protection of 

investors. 

10. Should the exemptive order 

providing the relief proposed herein 

include a sunset provision so that the 

relief would expire on a particular date? 

If yes, what would be an appropriate 

date on which the relief should expire 

(e.g., one year after the issuance of the 

exemptive order, etc.) and why? Please 

discuss the costs and benefits of 

including such a sunset provision in the 

exemptive order. Additionally, please 

explain why such a sunset provision 

would be necessary or appropriate in 

the public interest and consistent with 

the protection of investors. 

Alternatively, please explain why the 

exemptive order should omit a sunset 

provision, including a discussion of the 

benefits and costs of such omission or 

any distortive effects on the market. 

Lastly, please discuss whether there are 

alternative means of achieving any 

benefits of a sunset provision. 

By the Commission. 

Dated: December 22, 2020. 

Vanessa A. Countryman, 

Secretary. 

[FR Doc. 2020–28700 Filed 1–11–21; 8:45 am] 

BILLING CODE 8011–01–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R09–OAR–2019–0440; FRL–10018– 

44–Region 9] 

Clean Air Plans; 2008 8-Hour Ozone 

Nonattainment Area Requirements; 

Western Nevada County, California 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is proposing to approve, 

or conditionally approve, all or portions 

of a state implementation plan (SIP) 

revision submitted by the State of 

California to meet Clean Air Act (CAA 

or ‘‘Act’’) requirements for the 2008 8- 

hour ozone national ambient air quality 

standards (NAAQS or ‘‘standards’’) in 

the Nevada County (Western part), 

California ozone nonattainment area 

(‘‘Western Nevada County’’). The SIP 

revision is the ‘‘Ozone Attainment Plan, 

Western Nevada County, State 

Implementation Plan for the 2008 

Primary Federal 8-Hour Ozone Standard 

of .075 ppm’’ (‘‘2018 Western Nevada 

County Ozone Plan’’ or ‘‘Plan’’). The 

2018 Western Nevada County Ozone 

Plan addresses the Serious 

nonattainment area requirements for the 

2008 ozone NAAQS, including the 

requirements for emissions inventories, 

attainment demonstration, reasonable 

further progress, reasonably available 

control measures, and contingency 

measures, among others; and establishes 

motor vehicle emissions budgets. The 

EPA is proposing to approve the 2018 

Western Nevada County Ozone Plan as 

meeting all the applicable ozone 

nonattainment area requirements except 

for the contingency measures 

requirement, for which the EPA is 

proposing conditional approval. In 

addition, the EPA is beginning the 

adequacy process for the 2020 motor 

vehicle emissions budgets in the 2018 

Western Nevada County Ozone Plan 

through this proposed rulemaking. 

DATES: Written comments must arrive 

on or before February 11, 2021. 

ADDRESSES: Submit your comments, 

identified by Docket ID No. EPA–R09– 

OAR–2019–0440 at https://

www.regulations.gov. For comments 

submitted at Regulations.gov, follow the 

online instructions for submitting 

comments. Once submitted, comments 

cannot be edited or removed from 

Regulations.gov. The EPA may publish 

any comment received to its public 

docket. Do not submit electronically any 

information you consider to be 

Confidential Business Information (CBI) 

or other information whose disclosure is 

restricted by statute. Multimedia 

submissions (audio, video, etc.) must be 

accompanied by a written comment. 

The written comment is considered the 

official comment and should include 

discussion of all points you wish to 

make. The EPA will generally not 

consider comments or comment 

contents located outside of the primary 

submission (i.e., on the web, cloud, or 

other file sharing system). For 

additional submission methods, please 

contact the person identified in the FOR

FURTHER INFORMATION CONTACT section. 

For the full EPA public comment policy, 

information about CBI or multimedia 

submissions, and general guidance on 

making effective comments, please visit 

https://www.epa.gov/dockets/ 

commenting-epa-dockets. If you need 

assistance in a language other than 

English or if you are a person with 

disabilities who needs a reasonable 

accommodation at no cost to you, please 

contact the person identified in the FOR

FURTHER INFORMATION CONTACT section. 

FOR FURTHER INFORMATION CONTACT: T. 

Khoi Nguyen, Air Planning Office (AIR– 

2), EPA Region IX, 75 Hawthorne Street, 

San Francisco, CA 94105, (415) 947– 

4120, or by email at nguyen.thien@

epa.gov. 

SUPPLEMENTARY INFORMATION: 

Throughout this document, ‘‘we,’’ 

‘‘us,’’ and ‘‘our’’ refer to the EPA. 

Table of Contents 

I. Regulatory Context 

A. Ozone Standards, Area Designations, 

and SIPs 

B. The Western Nevada County Ozone 

Nonattainment Area 


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1The State of California refers to reactive organic 

gases (ROG) rather than VOC in some of its ozonerelated SIP submissions. As a practical matter, ROG 

and VOC refer to the same set of chemical 

constituents, and for the sake of simplicity, we refer 

to this set of gases as VOC in this proposed rule. 

2 ‘‘Fact Sheet—2008 Final Revisions to the 

National Ambient Air Quality Standards for Ozone’’ 

dated March 2008. 

3 44 FR 8202 (February 8, 1979). 

4 56 FR 56694 (November 6, 1991). 

5 62 FR 38856 (July 18, 1997). The 1-hour ozone 

standard was revoked effective June 15, 2005. See 

70 FR 44470 (August 3, 2005). 

6 69 FR 23857 (April 30, 2004). 

7 77 FR 28423 (May 14, 2012). For more details 

on the revised classification, see 77 FR 56775, 

56776 (September 14, 2012). 

8 77 FR 71551 (December 3, 2012). 

9 73 FR 16436 (March 27, 2008). The EPA further 

tightened the 8-hour ozone NAAQS to 0.070 ppm 

in 2015, but today’s proposed action relates to the 

requirements for the 2008 ozone NAAQS only. 

Information on the 2015 ozone NAAQS is available 

at 80 FR 65292 (October 26, 2015). 

10 77 FR 30088 (May 21, 2012). 

11 81 FR 26697 (May 4, 2016). 

12 83 FR 56781 (November 14, 2018). 

13See letter dated December 2, 2018, from 

Richard W. Corey, Executive Officer, CARB, to 

Michael Stoker, Regional Administrator, EPA 

Region IX, and letter dated November 14, 2018 from 

Gretchen Bennitt, Executive Director, NSAQMD, to 

Richard W. Corey, Executive Officer, CARB, subject 

‘‘Submittal of the Northern Sierra Air Quality 

Management District Ozone Attainment Plan for the 

2008 Federal 8-hour Ozone Standard.’’ 

14 84 FR 44238. The notice for this action 

acknowledges CARB’s request for voluntary 

reclassification, and notes that the EPA’s 

determination resulted in the same outcome as 

would occur with an approval of that request. 

C. CAA and Regulatory Requirements for 

2008 Ozone Nonattainment Area SIPs 

II. The 2018 Western Nevada County Ozone 

Plan 

A. Summary of Submission 

B. Clean Air Act Procedural Requirements 

for Adoption and Submission of SIP 

Revisions 

III. Evaluation of the 2018 Western Nevada 

County Ozone Plan 

A. Emissions Inventories 

B. Emissions Statements 

C. Reasonably Available Control Measures 

Demonstration 

D. Attainment Demonstration 

E. Rate of Progress Plan and Reasonable 

Further Progress Demonstration 

F. Contingency Measures 

G. Motor Vehicle Emissions Budgets for 

Transportation Conformity 

H. Other Clean Air Act Requirements 

Applicable to Serious Ozone 

Nonattainment Areas 

IV. Proposed Action 

V. Statutory and Executive Order Reviews 

I. Regulatory Context 

A. Ozone Standards, Area Designations, 

and SIPs 

Ground-level ozone pollution is 

formed from the reaction of volatile 

organic compounds (VOC) and oxides of 

nitrogen (NOX) in the presence of 

sunlight.1 These two pollutants, referred 

to as ozone precursors, are emitted by 

many types of sources, including on-and 

off-road motor vehicles and engines, 

power plants and industrial facilities, 

and smaller area sources such as lawn 

and garden equipment and paints. 

Scientific evidence indicates that 

adverse public health effects occur 

following exposure to ozone, 

particularly in children and adults with 

lung disease. Breathing air containing 

ozone can reduce lung function and 

inflame airways, which can increase 

respiratory symptoms and aggravate 

asthma or other lung diseases.2

Under section 109 of the CAA, the 

EPA promulgates NAAQS for pervasive 

air pollutants, such as ozone. The 

NAAQS are concentration levels that, 

the attainment and maintenance of 

which, the EPA has determined to be 

requisite to protect public health and 

welfare. Section 110 of the CAA 

requires states to develop and submit 

SIPs to implement, maintain, and 

enforce the NAAQS. 

In 1979, the EPA established the 1- 

hour ozone NAAQS of 0.12 parts per 

million (ppm) (referred to herein as the 

‘‘1-hour ozone NAAQS’’).3 All of 

Nevada County was designated 

‘‘Unclassifiable/Attainment’’ for the 1- 

hour standard on November 15, 1990.4

In 1997, the EPA revised the NAAQS 

for ozone, setting it at 0.08 ppm 

averaged over an 8-hour timeframe 

(referred to herein as the ‘‘1997 ozone 

NAAQS’’) to replace the existing 1-hour 

ozone NAAQS.5 In 2004, the EPA 

initially designated and classified 

Western Nevada County as a ‘‘Subpart 

1’’ nonattainment area for the 1997 

ozone NAAQS.6 In response to a 

decision of the United States Court of 

Appeals for the District of Columbia 

Circuit vacating the EPA’s subpart 1 

designations, the EPA in 2012 revised 

the area’s classification for the 1997 

ozone NAAQS to ‘‘Moderate,’’ with an 

outermost attainment date of June 15, 

2011.7 In 2011, the design value for the 

area was 0.079 ppm, and the EPA 

published a clean data determination on 

December 3, 2012, suspending 

attainment-related planning 

requirements for the 1997 ozone 

NAAQS.8

In 2008, the EPA lowered the 8-hour 

ozone NAAQS to 0.075 ppm (referred to 

herein as the ‘‘2008 ozone NAAQS’’) to 

replace the 1997 ozone NAAQS of 0.08 

ppm.9 In 2012, the EPA designated 

Western Nevada County as 

nonattainment for the 2008 ozone 

NAAQS and classified the area as 

Marginal.10 Areas classified as Marginal 

must attain the NAAQS within 3 years 

of the effective date of the 

nonattainment designation. For Western 

Nevada County, the applicable Marginal 

area attainment date was as 

expeditiously as practicable but no later 

than July 20, 2015. The area failed to 

attain the 2008 ozone NAAQS by this 

date, and the EPA published a 

reclassification to Moderate on May 4, 

2016.11 Upon reclassification, Western 

Nevada County was required to attain 

the 2008 ozone NAAQS as 

expeditiously as practicable but no later 

than July 20, 2018. 

In November 2018, pursuant to CAA 

section 181(b)(2), the EPA proposed to 

determine that the Western Nevada 

County Moderate nonattainment area 

failed to attain the 2008 ozone NAAQS 

by the Moderate area attainment date.12

Additionally, following the EPA’s 

November 2018 proposal, the California 

Air Resources Board (CARB) submitted 

a request under CAA section 181(b)(3) 

to voluntarily reclassify the Western 

Nevada County nonattainment area from 

Moderate to Serious nonattainment for 

the 2008 ozone standards accompanied 

by a SIP revision to address planning 

elements for a Serious area.13

In a final rule dated August 23, 2019, 

the EPA found that Western Nevada 

County failed to attain the 2008 ozone 

NAAQS by the applicable attainment 

date, and reclassified the area as Serious 

by operation of law, effective September 

23, 2019.14 Once reclassified to Serious, 

the area is required to attain the 

standard as expeditiously as practicable, 

but no later than 9 years after the initial 

designation as nonattainment, i.e., July 

20, 2021. 

The SIP revision that is the subject of 

today’s proposed action addresses the 

Serious nonattainment area 

requirements that apply to Western 

Nevada County for the 2008 ozone 

NAAQS. 

B. The Western Nevada County Ozone 

Nonattainment Area 

The Western Nevada County 

nonattainment area for the 2008 ozone 

NAAQS consists of the portion of 

Nevada County west of the ridge of the 

Sierra Nevada mountains. Western 

Nevada County encompasses an area of 

approximately 800 square miles. The 

nonattainment area is bounded on the 

north by the Middle Yuba River and 

most of the southern border is defined 

by the Bear River. The eastern boundary 

is a line running north/south that 

generally follows the ridge of the Sierra 


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15For a precise definition of the boundaries of the 

Western Nevada County 2008 ozone nonattainment 

area, see 40 CFR 81.305. 

16 2018 Western Nevada County Ozone Plan, page 

12. 

17 Isolated rural nonattainment and maintenance 

areas are defined in 40 CFR 93.101 as areas that do 

not contain or are not part of any metropolitan 

planning area as designated under the 

transportation planning regulations. 

18 80 FR 12264 (March 6, 2015). 

19South Coast Air Quality Management District v. 

EPA, 882 F.3d 1138 (D.C. Cir. 2018). The term 

‘‘South Coast II’’ is used in reference to the 2018 

court decision to distinguish it from a decision 

published in 2006 also referred to as ‘‘South Coast.’’ 

The earlier decision involved a challenge to the 

EPA’s Phase 1 implementation rule for the 1997 

ozone NAAQS. South Coast Air Quality 

Management Dist. v. EPA, 472 F.3d 882 (D.C. Cir. 

2006). 

20Letter dated December 2, 2018, from Richard 

Corey, Executive Officer, CARB, to Mike Stoker, 

Regional Administrator, U.S. Environmental 

Protection Agency Region 9. 

21NSAQMD Board Resolution 2018–7, October 

22, 2018; CARB Board Resolution 18–36, 2018 

Ozone Attainment Plan for Western Nevada County. 

22Letter dated November 16, 2020, from Richard 

Corey, Executive Officer, CARB, to John Busterud, 

Regional Administrator, EPA Region IX. CARB’s 

letter also forwarded the District’s commitment 

letter to the EPA. The District’s letter is dated 

October 26, 2020, from Gretchen Bennitt, NSAQMD 

Air Pollution Control Officer, to Richard Corey, 

CARB Executive Officer. 

23See attachment to email dated October 27, 2020 

from Nesamani Kalandiyur, CARB, to Khoi Nguyen 

and Karina O’Connor, EPA Region 9. 

Nevada mountains.15 The population of 

the Western Nevada County 

nonattainment area is about 83,000 

people.16

Air quality in Western Nevada County 

is regulated jointly by the Northern 

Sierra Air Quality Management District 

(NSAQMD or ‘‘District’’) and CARB. The 

Nevada County Transportation 

Commission (NCTC) is the regional 

transportation planning agency for the 

County of Nevada. For transportation 

planning purposes, the area is an 

isolated rural area.17

C. CAA and Regulatory Requirements 

for 2008 Ozone Nonattainment Area 

SIPs 

States must implement the 2008 

ozone NAAQS under title I, part D of 

the CAA, including sections 171–179B 

of subpart 1, ‘‘Nonattainment Areas in 

General,’’ and sections 181–185 of 

subpart 2, ‘‘Additional Provisions for 

Ozone Nonattainment Areas.’’ To assist 

states in developing effective plans to 

address ozone nonattainment problems, 

in 2015, the EPA issued a SIP 

Requirements Rule (SRR) for the 2008 

ozone NAAQS (‘‘2008 Ozone SRR’’) that 

addressed implementation of the 2008 

standards, including attainment dates, 

requirements for emissions inventories, 

attainment and reasonable further 

progress (RFP) demonstrations, among 

other SIP elements, as well as the 

transition from the 1997 ozone NAAQS 

to the 2008 ozone NAAQS and 

associated anti-backsliding 

requirements.18 The 2008 Ozone SRR is 

codified at 40 CFR part 51, subpart AA. 

We discuss the CAA and regulatory 

requirements for the elements of 2008 

ozone plans relevant to this proposal in 

more detail in Section III of this 

document. 

The EPA’s 2008 Ozone SRR was 

challenged, and on February 16, 2018, 

the U.S. Court of Appeals for the D.C. 

Circuit (‘‘D.C. Circuit’’) published its 

decision in South Coast Air Quality 

Management. District v. EPA (‘‘South 

Coast II’’) 19 vacating portions of the 

2008 Ozone SRR. The only aspect of the 

South Coast II decision that relates to 

this proposed action is the vacatur of 

the alternative baseline year for RFP 

plans. More specifically, the 2008 

Ozone SRR required states to develop 

the baseline emissions inventory for 

RFP plans using the emissions 

inventory for the most recent calendar 

year for which states submit a triennial 

inventory to the EPA under subpart A, 

‘‘Air Emissions Reporting 

Requirements,’’ of 40 CFR part 51, 

which was 2011. The 2008 Ozone SRR, 

however, allowed states to use an 

alternative year, between 2008 and 

2012, for the baseline emissions 

inventory provided the state 

demonstrated why the alternative 

baseline year was appropriate. In the 

South Coast II decision, the D.C. Circuit 

vacated the provisions of the 2008 

Ozone SRR that allowed states to use an 

alternative baseline year for 

demonstrating RFP. 

II. The 2018 Western Nevada County 

Ozone Plan 

A. Summary of Submission 

On December 2, 2018, CARB 

submitted the 2018 Western Nevada 

County Ozone Plan to the EPA as a 

revision to the California SIP to address 

the nonattainment area requirements for 

Western Nevada County for the 2008 

ozone NAAQS.20 The 2018 Western 

Nevada County Ozone Plan includes 

various chapters and appendices, 

described further below, plus the 

District’s resolution of adoption for the 

Plan (District Resolution 2018–07) and 

CARB’s resolution of adoption of the 

Plan as a revision to the California SIP 

(CARB Resolution 18–36).21 The Plan 

addresses the CAA requirements for 

emissions inventories, air quality 

modeling demonstrating attainment, 

reasonably available control measures 

(RACM), RFP, and motor vehicle 

emissions budgets, among other 

requirements. 

The 2018 Western Nevada County 

Ozone Plan begins with an executive 

summary, an introductory section 

discussing ozone pollution and the 

Western Nevada County nonattainment 

area generally, a discussion about 

specific challenges in meeting air 

quality standards in the area, and a 

formal request to reclassify the area to 

Serious for the 2008 ozone NAAQS. 

Chapters IV through XIII address 

specific planning elements for a Serious 

area, including emissions inventory, 

transportation conformity budgets, 

emissions statements, new source 

review (NSR), RACM, RFP, attainment 

demonstration, and contingency 

measures. The Plan also includes eight 

appendices providing additional 

information on emissions inventories, 

CARB control measures, CARB analysis 

of key mobile source regulations and 

programs, a mobile sources and 

consumer products RACM 

demonstration, and the modeled 

attainment demonstration, a modeling 

emissions inventory for the 

nonattainment area, a description of the 

conceptual model for the nonattainment 

area, and CARB’s modeling protocol 

used for the photochemical modeling. 

Additionally, to further supplement 

the contingency measures element of 

the 2018 Western Nevada County Ozone 

Plan, CARB forwarded an October 26, 

2020 letter from the District 22

committing to adopt as a rule the most 

recent Architectural Coatings Suggested 

Control Measure (SCM) developed and 

approved by CARB to serve as a 

contingency measure that would be 

triggered if the area fails to meet an RFP 

milestone for the 2008 ozone NAAQS or 

to reach attainment by a July 20, 2021 

attainment date. In the letter forwarding 

this commitment, dated November 16, 

2020, CARB commits to submit the new 

District rule to the EPA as a SIP revision 

within 12 months of the EPA’s final 

action on the contingency measures 

element of the 2018 Western Nevada 

County Ozone Plan. 

In a technical memorandum 

submitted by email on October 27, 2020, 

CARB provided additional information 

related to the motor vehicle emissions 

budgets in the 2018 Western Nevada 

County Ozone Plan.23 Additionally, 

CARB has provided a copy of the 2019 

emissions inventory for the 


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24Email dated May 14, 2020 from Earl 

Withycombe, CARB, to Khoi Nguyen, EPA Region 

9, for attachment of the 2019 emission inventory for 

the nonattainment area. 

25Email dated August 17, 2020 from Webster 

Tasat, CARB, to Khoi Nguyen, EPA Region 9, for 

clarifications of the emission tables. 

26Affidavit of Publication from Nevada County 

Publishing Company including a copy of the proof 

of publication and of the September 21, 2018 notice 

for the October 22, 2018 public hearing. 

27See NSAQMD Resolution #2018–07, October 

22, 2018. 

28Notice of Public Meeting to Consider the Ozone 

Attainment Plan for Western Nevada County, 

signed by Richard Corey, Executive Officer, CARB, 

October 12, 2018. 

29CARB Resolution 18–36. 30Letter dated June 20, 2019, from Elizabeth 

Adams, Director, Air and Radiation Division, EPA 

Region IX, to Richard Corey, Executive Officer, 

CARB. The Plan was deemed complete by operation 

of law on June 2, 2019, 6 months after submittal, 

but the EPA completeness finding for the following 

SIP elements: Contingency measures for VOC and 

NOX; emissions statement; ozone attainment 

demonstration; and RFP demonstration for VOC 

and NOX for moderate nonattainment areas was 

necessary to stop clocks for mandatory sanctions in 

the Western Nevada nonattainment area under 

section 179(a) of the CAA resulting from a 

December 11, 2017 finding of failure to submit. See 

82 FR 58118. 

31 2008 Ozone SRR at 40 CFR 51.1115(a) and the 

Air Emissions Reporting Requirements at 40 CFR 

part 51, subpart A. 

32 ‘‘Emissions Inventory Guidance for 

Implementation of Ozone and Particulate Matter 

National Ambient Air Quality Standards (NAAQS) 

and Regional Haze Regulations,’’ EPA–454/B–17– 

002, May 2017. At the time the 2018 Western 

Nevada County Ozone Plan was developed, the 

following EPA emissions inventory guidance 

applied: ‘‘Emissions Inventory Guidance for 

Implementation of Ozone and Particulate Matter 

National Ambient Air Quality Standards (NAAQS) 

and Regional Haze Regulations,’’ EPA–454–R–05– 

001, August 2005. 

33 40 CFR 51.1115(a) and (c), and 40 CFR 

51.1100(bb) and (cc). 

34 80 FR 12264, at 12290 (March 6, 2015). 

35 ‘‘Staff Report: CARB Review of the Ozone 

Attainment Plan for Western Nevada County,’’ 

CARB, October 12, 2018, page 6 (‘‘CARB Staff 

Report’’). 

nonattainment area,24 and clarifications 

to emissions tables in the Plan.25

B. Clean Air Act Procedural 

Requirements for Adoption and 

Submission of SIP Revisions 

CAA sections 110(a) and 110(l) 

require a state to provide reasonable 

public notice and opportunity for public 

hearing prior to the adoption and 

submission of a SIP or SIP revision. To 

meet this requirement, every SIP 

submittal should include evidence that 

adequate public notice was given and an 

opportunity for a public hearing was 

provided consistent with the EPA’s 

implementing regulations in 40 CFR 

51.102. 

Both the District and CARB have 

satisfied the applicable statutory and 

regulatory requirements for reasonable 

public notice and hearing prior to the 

adoption and submittal of the 2018 

Western Nevada County Ozone Plan. On 

September 21, 2018, the District 

published a notice in the local 

newspaper of a public hearing to be 

held on October 22, 2018, for the 

adoption of the 2018 Western Nevada 

County Ozone Plan.26 The District 

adopted the Plan through Resolution 

#2018–07 at the October 22, 2018 

hearing, and directed the Executive 

Director to forward the Plan to CARB for 

inclusion in the California SIP.27

CARB also provided public notice and 

opportunity for public comment on the 

2018 Western Nevada County Ozone 

Plan. On October 12, 2018, CARB 

released for public review its Staff 

Report for the Plan and published a 

notice of public meeting to be held on 

November 15, 2018, to consider 

adoption.28 At the November 15, 2018 

hearing, CARB adopted the Plan as a 

revision to the California SIP, excluding 

those portions not required to be 

submitted to the EPA, and directed the 

Executive Officer to submit the Plan to 

the EPA for approval into the California 

SIP. On December 2, 2018, the 

Executive Officer of CARB submitted 

the Plan to the EPA, including the 

CARB Board resolution adopting the 

2018 Western Nevada County Ozone 

Plan.29 On June 20, 2019, the EPA 

determined that certain portions of this 

submittal applicable to the 2008 ozone 

NAAQS were complete.30

Based on information provided in the 

SIP revision summarized above, the 

EPA has determined that all hearings 

were properly noticed. Therefore, we 

find that the submittal of the 2018 

Western Nevada County Ozone Plan 

meets the procedural requirements for 

public notice and hearing in CAA 

sections 110(a) and 110(l) and 40 CFR 

51.102. 

III. Evaluation of the 2018 Western 

Nevada County Ozone Plan 

A. Emissions Inventories 

1. Statutory and Regulatory 

Requirements 

CAA sections 172(c)(3) and 182(a)(1) 

require states to submit for each ozone 

nonattainment area a ‘‘base year 

inventory’’ that is a comprehensive, 

accurate, current inventory of actual 

emissions from all sources of the 

relevant pollutant or pollutants in the 

area. In addition, the 2008 Ozone SRR 

requires that the inventory year be 

selected consistent with the baseline 

year for the RFP demonstration, which 

is the most recent calendar year for 

which a complete triennial inventory is 

required to be submitted to the EPA 

under the Air Emissions Reporting 

Requirements.31

The EPA has issued guidance on the 

development of base year and future 

year emissions inventories for ozone 

and other pollutants.32 Emissions 

inventories for ozone must include 

emissions of VOC and NOX and 

represent emissions for a typical ozone 

season weekday.33 States should 

include documentation explaining how 

the emissions data were calculated. In 

estimating mobile source emissions, 

states should use the latest emissions 

models and planning assumptions 

available at the time the SIP is 

developed.34

Future baseline emissions inventories 

must reflect the most recent population, 

employment, travel and congestion 

projections for the area. In this context, 

future ‘‘baseline’’ emissions inventories 

refer to emissions estimates for a given 

year and area that reflect rules and 

regulations and other measures that are 

already adopted and that consider 

expected growth. Future baseline 

emissions inventories are necessary to 

show the projected effectiveness of SIP 

control measures. Both the base year 

and future year inventories are 

necessary for photochemical modeling 

to demonstrate attainment. 

2. Summary of State’s Submission 

The 2018 Western Nevada County 

Ozone Plan includes base year (2011) 

and future year (2012, 2014, 2017, 2020, 

and 2021) baseline inventories for NOX

and VOC for the Western Nevada 

County ozone nonattainment area. 

Documentation for the inventories are 

found in Chapter IV, ‘‘Emissions 

Inventory Background,’’ Chapter V, 

‘‘Summary of Emissions Inventory 

Methodologies,’’ Appendix A, 

‘‘Emissions Inventories for 2011, 2012, 

2014, 2017, 2020 and 2021,’’ and 

Appendix F, ‘‘Modeling Emission 

Inventory for the 8-Hour Ozone State 

Implementation Plan in Western Nevada 

County Non-attainment Area (WNNA).’’ 

The emissions inventories represent 

average summer day emissions, 

consistent with the observation that 

higher ozone levels in Western Nevada 

County typically occur from May 

through October. The 2011 base year 

and future year inventories in the 2018 

Western Nevada County Ozone Plan 

reflect District rules and CARB 

regulations submitted through 

November 2016.35 The mobile source 

portions of both base year and projected 

future year inventories were developed 

using California’s EPA-approved mobile 

source emissions model, EMFAC2014, 


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36EMFAC is short for EMission FACtor. In 

December 2015, the EPA approved EMFAC2014 for 

SIP development and transportation conformity 

purposes in California. 80 FR 77337 (December 14, 

2015). EMFAC2014 was the most recently approved 

version of the EMFAC model that was available at 

the time of preparation of the Western Nevada 

County Ozone Attainment Plan. The EPA recently 

approved an updated version of the EMFAC model, 

EMFAC2017, for future SIP development and 

transportation purposes in California. 84 FR 41717 

(August 15, 2019). 

37The Air Pollution Control Officer of the 

NSAQMD may waive the applicability of the 

reporting required by District Rule 513 for certain 

classes or categories of sources with actual 

emissions or potential to emit less than 10 tons per 

year of actual facility-wide VOC or NOX emissions 

if the emissions for the class or category of source 

are included in the base year and periodic emission 

inventories and the emissions are calculated using 

emission factors established by the EPA or other 

methods acceptable to the EPA. As described in 

Section B of this document, this approach is 

consistent with CAA section 182(a)(3)(B)(ii). 

38 2018 Western Nevada County Ozone Plan, page 

23. 

for estimating on-road motor vehicle 

emissions.36

Emissions estimates of VOC and NOX

in the 2018 Western Nevada County 

Ozone Plan are grouped into three 

categories: (1) Stationary point sources, 

(2) areawide sources, (3) on-road and 

other mobile sources. Stationary point 

sources refer to larger sources that have 

a fixed geographic location, such as 

power plants, industrial engines, and oil 

storage tanks. This inventory includes 

emissions from stationary internal 

combustion engines and gasoline 

dispensing facilities; these are not 

inventoried individually but estimated 

as a group and reported as an aggregated 

total. Areawide sources are emissions 

sources occurring over a wide 

geographic area, such as consumer 

products and architectural coatings. The 

on-road sources include light-duty 

automobiles, light-, medium-, and 

heavy-duty trucks, and motorcycles. 

Other mobile (off-road) sources include 

aircraft, recreational boats, and off-road 

equipment. 

For the 2018 Western Nevada County 

Ozone Plan, stationary point source 

emissions for the 2011 base year 

emissions inventory are based on 

reported data from all stationary point 

sources in Western Nevada County 

using the District’s annual emissions 

reporting program, which applies under 

District Rule 513, ‘‘Emissions 

Statements and Recordkeeping,’’ to 

stationary sources that emit VOC or 

NOX.37 Areawide sources include 

smaller emissions sources distributed 

across the nonattainment area. CARB 

and the District estimate emissions for 

areawide sources using the most recent 

models and methodologies, including 

publicly available emission factors and 

activity information. CARB also 

reviewed the growth profiles for point 

and areawide source categories and 

updated them as necessary to ensure 

that the emission projections are based 

on data that reflect historical trends, 

current conditions, and recent economic 

and demographic forecasts. Growth 

forecasts for most point and areawide 

sources were developed by CARB. 

On-road emissions inventories in the 

2018 Western Nevada County Ozone 

Plan are based on 2012 travel activity 

data provided by the California 

Department of Motor Vehicles. CARB 

provided emissions inventories for offroad equipment, including locomotives, 

pleasure craft and recreational vehicles, 

in-use off-road equipment, transport 

refrigeration units, cargo handling 

equipment, diesel agricultural 

equipment, and fuel storage and 

handling. Emissions from off-road 

sources were estimated using a suite of 

category-specific models or, where a 

new model was not available, the 

OFFROAD2007 model. A detailed list of 

the updates made to specific emissions 

inventory categories can be found in 

Chapter V. 

CARB developed the emission 

forecasts in the 2018 Western Nevada 

County Ozone Plan by applying growth 

and control profiles to the base year 

inventory. Growth profiles for stationary 

point and areawide sources are derived 

from surrogates such as economic 

activity, fuel usage, population, housing 

units, etc. Growth projections were 

obtained from government entities with 

expertise in developing forecasts for 

specific sectors, and from econometric 

models. Control profiles, which account 

for emissions reductions resulting from 

adopted rules and regulations, are 

derived from data provided by the 

regulatory agencies responsible for the 

affected emission categories.38

Table 1 provides a summary of the 

District’s 2011 base year, 2012 baseline 

year for modeling, and 2020 attainment 

year baseline VOC and NOX emissions 

estimates in tons per day (tpd) for an 

average summer day. All inventory 

years in the 2018 Western Nevada 

County Ozone Plan are derived from the 

2011 base year inventory, except that 

2012 is used as the baseline year for 

attainment modeling. These inventories 

provide the basis for the control 

measure analysis and the attainment 

demonstration in the Plan. Based on the 

inventory for 2011, mobile sources are 

the predominant sources for both VOC 

and NOX emissions. For a more detailed 

discussion of the inventories, see 

Appendix A of the Plan. 

TABLE 1—WESTERN NEVADA 2011 BASE YEAR, 2012 BASELINE YEAR FOR MODELING, AND 2020 ATTAINMENT YEAR

EMISSIONS INVENTORIES

[Summer planning inventory, tpd] 

Category 

2011 2012 2020 

VOC NOX VOC NOX VOC NOX

Stationary ................................................. 0.7620 0.0999 0.7006 0.0997 0.7843 0.0918 

Area Sources ........................................... 1.4109 0.1452 1.3946 0.1349 1.5150 0.1377 

On-Road and Other Mobile Sources ....... 3.3227 5.4415 3.1131 4.9124 1.9559 2.8886 

Total for Western Nevada County 

Nonattainment Area ...................... 5.4956 5.6866 5.2083 5.1470 4.2552 3.1181 

Source: 2018 Western Nevada County Ozone Plan, Appendix A. The sum of the emissions values may not equal the total shown due to

rounding of the numbers. 

3. The EPA’s Review of the State’s 

Submission 

We have reviewed the 2011 base year 

emissions inventory in the 2018 

Western Nevada County Ozone Plan and 

the inventory methodologies used by 

the District and CARB for consistency 

with CAA requirements and EPA 

guidance. First, as required by EPA 

regulation, we find that the 2011 

inventory includes estimates for VOC 

and NOX for a typical ozone season 


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39See 81 FR 39424 (June 16, 2016), 82 FR 14446 

(March 21, 2017), and 83 FR 23232 (May 18, 2018). 

40 80 FR 12264, at 12291 (March 6, 2015). 

41 82 FR 28240. 

42 40 CFR 51.1112(c). 

43See General Preamble, 57 FR 13498 at 13560 

(April 16, 1992) and memorandum dated November 

30, 1999, from John Seitz, Director, OAQPS, to 

Regional Air Directors, titled ‘‘Guidance on the 

Reasonably Available Control Measure Requirement 

and Attainment Demonstration Submissions for 

Ozone Nonattainment Areas.’’ 

weekday, and that the Plan provides 

adequate documentation explaining 

how the emissions are calculated. 

Second, we find that the 2011 base 

year emissions inventory in the Plan 

reflects appropriate emissions models 

and methodologies, and, therefore, 

represents a comprehensive, accurate, 

and current inventory of actual 

emissions during that year in the 

Western Nevada County nonattainment 

area. Therefore, the EPA is proposing to 

approve the 2011 emissions inventory 

in the 2018 Western Nevada County 

Ozone Plan as meeting the requirements 

for a base year inventory set forth in 

CAA section 182(a)(1) and 40 CFR 

51.1115. 

With respect to future year baseline 

projections, we have reviewed the 

growth and control factors and find 

them acceptable and conclude that the 

future baseline emissions projections in 

the 2018 Western Nevada County Ozone 

Plan reflect appropriate calculation 

methods and the latest planning 

assumptions. 

Furthermore, we note that the future 

year baseline projections take into 

account emissions reductions from 

control measures in adopted state and 

local rules and regulations. As a general 

matter, the EPA will approve a SIP 

revision that takes emissions reduction 

credit for such control measures only 

where the EPA has approved the control 

measures as part of the SIP. See 

Appendix B of the 2018 Western 

Nevada County Ozone Plan, ‘‘CARB 

Control Measures, 1985 to 2016,’’ 2018 

Western Nevada County Ozone Plan for 

the list of control measures. 

With respect to mobile sources, the 

EPA has taken action in recent years to 

approve CARB mobile source 

regulations into the California SIP.39 We 

therefore find that the future year 

baseline projections in the 2018 Western 

Nevada County Ozone Plan are properly 

supported by SIP-approved stationary 

and mobile source control measures. 

B. Emissions Statements 

1. Statutory and Regulatory 

Requirements 

Section 182(a)(3)(B)(i) of the Act 

requires each state to submit a SIP 

revision requiring owners or operators 

of stationary sources of VOC or NOX to 

provide the state with statements of 

actual emissions from such sources. 

Statements must be submitted at least 

every year and must contain a 

certification that the information 

contained in the statement is accurate to 

the best knowledge of the individual 

certifying the statement. Section 

182(a)(3)(B)(ii) of the Act allows states 

to waive the emissions statement 

requirement for any class or category of 

stationary sources that emit less than 25 

tpy of VOC or NOX, if the state provides 

an inventory of emissions from such 

class or category of sources as part of the 

base year or periodic inventories 

required under CAA sections 182(a)(1) 

and 182(a)(3)(A), based on the use of 

emission factors established by the EPA 

or other methods acceptable to the EPA. 

The preamble of the 2008 Ozone SRR 

states that if an area has a previously 

approved emissions statement rule for 

the 1997 ozone NAAQS or the 1-hour 

ozone NAAQS that covers all portions 

of the nonattainment area for the 2008 

ozone NAAQS, such rule should be 

sufficient for purposes of the emissions 

statement requirement for the 2008 

ozone NAAQS.40 The state should 

review the existing rule to ensure it is 

adequate and, if so, may rely on it to 

meet the emission statement 

requirement for the 2008 ozone NAAQS. 

Where an existing emissions statement 

program is still adequate to meet the 

requirements of this rule, states can 

provide the rationale for that 

determination to the EPA in a written 

statement in the SIP to meet this 

requirement. States should identify the 

various requirements and how each is 

met by the existing emissions statement 

program. Where an emissions statement 

requirement is modified for any reason, 

states must provide the revision to the 

emissions statement as part of its SIP. 

2. Summary of the State’s Submission 

The 2018 Western Nevada County 

Ozone Plan addresses compliance with 

the emissions statement requirement in 

CAA section 182(a)(3)(B) for the 2008 

ozone NAAQS by reference to District 

Rule 513, ‘‘Emission Statements and 

Recordkeeping,’’ which, among other 

things, requires emissions reporting 

from all stationary sources of NOX and 

VOC greater than or equal to 10 tpy. The 

EPA approved District Rule 513 as a 

revision to the California SIP on June 

21, 2017, finding that Rule 513 fulfills 

the relevant emissions statement 

requirements of CAA section 

182(a)(3)(B)(i).41

3. The EPA’s Review of the State’s 

Submission 

We find that District Rule 513 applies 

within the entire ozone nonattainment 

area; applies to all stationary sources 

emitting NOX and VOC, except those 

emitting less than 10 tpy for which the 

District has waived the requirement 

(consistent with CAA section 

182(a)(3)(B)(ii)); and requires reporting, 

on an annual basis, of total emissions of 

VOC and NOX. Also, as required under 

CAA section 182(a)(3)(B), District Rule 

513 requires certification that the 

information provided to the District is 

accurate to the best knowledge of the 

individual certifying the emissions data. 

Therefore, for the reasons described in 

the preceding paragraph, we propose to 

find that District Rule meets the 

emissions statement requirements for 

the 2008 ozone NAAQS under CAA 

section 182(a)(3)(B). 

C. Reasonably Available Control 

Measures Demonstration 

1. Statutory and Regulatory 

Requirements 

CAA section 172(c)(1) requires that 

each attainment plan provide for the 

implementation of all RACM as 

expeditiously as practicable (including 

such reductions in emissions from 

existing sources in the area as may be 

obtained through implementation of 

reasonably available control technology 

(RACT)), and also provide for 

attainment of the NAAQS. The 2008 

Ozone SRR requires that, for each 

nonattainment area required to submit 

an attainment demonstration, the state 

concurrently submit a SIP revision 

demonstrating that it has adopted all 

RACM necessary to demonstrate 

attainment as expeditiously as 

practicable and to meet any RFP 

requirements.42

The EPA has previously provided 

guidance interpreting the RACM 

requirement in the General Preamble for 

the Implementation of the CAA 

Amendments of 1990 (‘‘General 

Preamble’’) and in a memorandum 

entitled ‘‘Guidance on the Reasonably 

Available Control Measure Requirement 

and Attainment Demonstration 

Submissions for Ozone Nonattainment 

Areas.’’ 43 In short, to address the 

requirement to adopt all RACM, states 

should consider all potentially 

reasonable control measures for source 

categories in the nonattainment area to 

determine whether they are reasonably 

available for implementation in that 

area and whether they would, if 

implemented individually or 

collectively, advance the area’s 


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44 Id. See also 44 FR 20372 (April 4, 1979), and 

memorandum dated December 14, 2000, from John 

S. Seitz, Director, OAQPS, to Regional Air 

Directors, titled ‘‘Additional Submission on RACM 

From States with Severe One-Hour Ozone 

Nonattainment Area SIPs.’’ 

45For ozone nonattainment areas classified as 

Moderate or above, CAA section 182(b)(2) also 

requires implementation of RACT for all major 

sources of VOC and for each VOC source category 

for which the EPA has issued a control techniques 

guideline. CAA section 182(f) requires that RACT 

under section 182(b)(2) also apply to major 

stationary sources of NOX. In Serious areas, a major 

source is a stationary source that emits or has the 

potential to emit at least 50 tpy of VOC or NOX (see 

CAA section 182(c) and (f)). Under the 2008 Ozone 

SRR, states were required to submit SIP revisions 

meeting the RACT requirements of CAA sections 

182(b)(2) and 182(f) no later than 24 months after 

the effective date of designation for the 2008 Ozone 

NAAQS and to implement the required RACT 

measures as expeditiously as practicable but no 

later than January 1 of the 5th year after the 

effective date of designation (see 40 CFR 

51.1112(a)). California submitted the CAA section 

182 RACT SIP for Western Nevada County for the 

2008 ozone NAAQS on June 7, 2018. Although 

Western Nevada County was classified as Moderate 

nonattainment for the 2008 ozone NAAQS at the 

time of submittal, the RACT SIP evaluated the area 

for compliance with applicable RACT requirements 

based on the 50 tpy Serious major source 

thresholds, in anticipation of the area’s 

reclassification to the higher classification. The EPA 

found this submission complete on November 29, 

2018 (see letter dated November 29, 2018 from 

Elizabeth Adams, Acting Director, Air Divison, EPA 

Region IX, to Richard Corey, Executive Officer, 

California Air Resources Board, and finalized the 

RACT SIP submission on January 15, 2020 (85 FR 

2313). 

46The EPA approved the District’s RACT SIP on 

January 15, 2020. 85 FR 2313. 

47 2018 Western Nevada County Ozone Plan, page 

42. 

48For a further breakdown of the area’s NOX and 

VOC sources, see Table 3 of the EPA’s December 3, 

2020 memorandum to file. 

49Architectural coatings is Western Nevada 

County’s third largest VOC source category. The 

largest VOC source categories in the area are 

consumer products and asphalt paving/roofing, and 

they are already regulated, respectively, by multiple 

CARB regulations and District Rule 227. See Table 

3 of our December 3, 2020 memorandum to file. 

50The emission reductions from the adopting an 

architectural coatings rule for VOC (0.010 tpd) is 

less than the value needed to advance attainment 

by a year for VOC (0.075 tpd), as calculated below 

in Section III.C.3. 

51Transportation Plan, Appendix D, page D–1. 

attainment date by one year or more.44

Any measures that are necessary to meet 

these requirements that are not already 

either federally promulgated, or part of 

the state’s SIP, must be submitted in 

enforceable form as part of the state’s 

attainment plan for the area.45

2. Summary of the State’s Submission 

For the 2018 Western Nevada County 

Ozone Plan, the District and CARB each 

undertook a process to identify and 

evaluate potential RACM that could 

contribute to expeditious attainment of 

the 2008 ozone NAAQS in Western 

Nevada County. We describe each 

agency’s efforts below. 

a. District’s RACM Analysis 

The District’s RACM demonstration 

for the 2008 ozone NAAQS is described 

in Chapter X, ‘‘Reasonably Available 

Control Measures Demonstration,’’ of 

the 2018 Western Nevada County Ozone 

Plan. This discussion summarizes the 

District’s analysis of potential additional 

control measures for stationary sources 

conducted in the District’s RACT SIP,46

and describes additional controls in 

place for ‘‘areawide’’ source categories, 

such as architectural and automotive 

coatings. Chapter X and Appendices B– 

D discuss CARB’s mobile source and 

consumer products RACM assessment. 

The District concludes that there are no 

additional control measures reasonably 

available in the area that can advance 

attainment by a year or more. 

The District’s RACM analysis builds 

upon a foundation of District rules 

developed for earlier ozone plans and 

approved as part of the SIP.47 The 

District has adopted rules to address 

various source categories of NOX and 

VOC. We provide a list of the District’s 

NOX and VOC rules approved into the 

California SIP in Table 1 of our 

December 3, 2020 memorandum to file 

in the docket for this proposed action. 

The SIP-approved District VOC or NOX

rules listed in Table 1 of our 

memorandum establish emission limits 

or other types of emissions controls for 

a wide range of sources, including 

incinerator burning, orchard or citrus 

heaters, fossil fuel steam generator 

facilities, gas stations, and more. These 

rules have already provided significant 

and ongoing reductions toward 

attainment of the 2008 ozone NAAQS 

by 2021. 

Tables 2 and 3 of the December 3, 

2020 memorandum provide a crosswalk 

of the area’s top-emitting stationary and 

area source categories of NOX and VOC 

with related District control rules. As 

shown in these tables, the area’s 2020 

stationary and area source emissions 

inventory includes about 0.23 tpd of 

NOX and 2.20 tpd of VOC. The top NOX

source categories for this year are 

residential fuel combustion (0.13 tpd; 

4.26 percent of 2020 inventory) and 

service/commercial fuel combustion 

(0.04 tpd; 1.25 percent of 2020 

inventory); all other categories each 

represent less than 1 percent of the 2020 

inventory.48 The top VOC source 

categories for this year are consumer 

products (0.44 tpd; 10.28 percent of 

2020 inventory), asphalt paving/roofing 

(0.38 tpd; 8.98 percent of 2020 

inventory), and architectural coatings 

(0.32 tpd; 7.55 percent of 2020 

inventory). 

The District’s October 26, 2020 

commitment letter for contingency 

measures includes further analysis of 

potential additional controls for 

regulated high-emission source 

categories. As mentioned above, the two 

largest NOX source categories are 

residential fuel combustion and service/ 

commercial fuel combustion. For 

residential fuel combustion, the District 

evaluated Sacramento Metropolitan Air 

Quality Management District 

(SMAQMD) Rule 414 for water heaters, 

boilers, and process heaters rated less 

than a million BTU per hour. Based on 

its analysis, and considering especially 

the low population in the 

nonattainment area, the District 

concluded that potential cumulative 

reductions in NOX from a similar rule in 

the District would produce only about 

0.0005 tpd each year, and that these 

reductions would occur too slowly to 

make any meaningful difference in 

attainment. For service/commercial fuel 

combustion, the District evaluated 

SMAQMD Rule 419 for miscellaneous 

combustion units. The District 

concluded that emission reductions 

from applying Rule 419 controls in the 

area would be approximately zero, 

because applying the rule would not be 

feasible for two of the three sources in 

the nonattainment area that would be 

subject to the rule and would not result 

in a more stringent emissions limit for 

the last applicable source in the 

nonattainment area. For VOC 

reductions, the District evaluated state 

measures for architectural coatings and 

automotive coatings,49 and found that 

reductions would be equivalent to 0.010 

tpd and 0.003 tpd, respectively. The 

District found that the estimated 

reductions for automotive coatings was 

negligible and not cost effective but 

committed to adopting a rule for 

architectural coatings as a contingency 

measure.50

Transportation Control Measures 

(TCMs) are projects that reduce air 

pollutants from transportation sources 

by reducing vehicle use, traffic 

congestion, or vehicle miles traveled. 

The Nevada County Regional 

Transportation Plan 2015–2035 

(‘‘Transportation Plan’’), prepared by 

NCTC in January 2018, summarizes and 

highlights TCMs in Nevada County, 

including the Western portion of 

Nevada County, and is included in the 

docket for this action. Sample measures 

in Western Nevada County are included 

within the TCM categories of CAA 

section 108(f)(1)(A). They include 

proposed bikeways, for example, in 

Grass Valley,51 a 511 traveler 


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52Transportation Plan, page 126. 

53Transportation Plan, Tables 42–46. 

54See, e.g., the EPA’s approval of standards and 

other requirements to control emissions from in-use 

heavy-duty diesel-powered trucks, at 77 FR 20308 

(April 4, 2012), revisions to the California on-road 

reformulated gasoline and diesel fuel regulations at 

75 FR 26653 (May 12, 2010), and revisions to the 

California motor vehicle inspection and 

maintenance program at 75 FR 38023 (July 1, 2010). 

55 2018 Western Nevada County Ozone Plan, page 

51 and Appendix D, ‘‘Reasonably Available Control 

Measures Assessment for Mobile Sources and 

Consumer Products.’’ 

56CARB’s consumer product measures are found 

in Title 17 California Code of Regulations section 

94500 et seq. The compilation of such measures 

that have been approved into the California SIP, 

including Federal Register citations, is available at: 

https://www.epa.gov/sips-ca/epa-approvedregulations-california-sip. EPA’s most recent 

approval of amendments to California’s consumer 

products regulations was in 2014. 79 FR 62346 

(October 17, 2014). 

57Appendix VI–A, Attachment VI–A–3, page VI– 

A–106. 

58 2018 Western Nevada County Ozone Plan, page 

41. As explained in Section III.D.2.a of this 

document, Western Nevada County is ‘‘NOX

limited’’ because ozone formation in the area is 

driven primarily by NOX emissions. As a result, 

reducing NOX emissions is more effective for 

reducing ozone than reducing VOC emissions. 

59The Plan’s RACM analysis incorrectly 

identifies the necessary year-to-year reductions as 

0.06 tpd of VOC and 0.23 tpd of NOX, based on a 

comparison of 2020 and 2021 inventories. Given the 

small discrepancy in these numbers, relative to the 

emission reductions available in the area, we find 

that the District’s RACM analysis is adequately 

supported. 

60 63 FR 48819 (September 11, 1998). 

information system that provides 

information on ridesharing and directs 

drivers to other regional resources for 

carpools and vanpools,52 and programs 

for improved public transit,53 including 

improvements and maintenance for bus 

stops and shelters. 

As explained above, the District 

identified potential candidate measures 

for RACM based upon categories with 

high NOX and VOC emissions and 

relevant local or state measures. This 

analysis was included in the District’s 

commitment letter for contingency 

measures and is further described in 

Section III.F.2. Based on its evaluation 

of all available measures and the NOXlimited nature of the nonattainment 

area, the District concludes that the 

District’s existing rules for stationary 

and area sources are generally as 

stringent as, or more stringent than the 

analogous rules in other districts. 

Further, the District concludes that, 

based on its comprehensive review and 

evaluation of potential candidate 

measures, the District meets the RACM 

requirement for the 2008 ozone NAAQS 

for all sources under the District’s 

jurisdiction. 

b. CARB’s RACM Analysis 

CARB’s RACM analysis is contained 

in Chapter X as well as Appendices 

B–D of the 2018 Western Nevada 

County Ozone Plan. CARB’s RACM 

analysis provides a general description 

of CARB’s existing mobile source 

programs. A more detailed description 

of CARB’s mobile source control 

program, including a comprehensive 

table listing on- and off-road mobile 

source regulatory actions taken by 

CARB since 1985, is contained in 

Appendix A. The RACM assessment 

contains CARB’s evaluation of mobile 

source and other statewide control 

measures that reduce emissions of NOX

and VOC in Western Nevada County. 

Source categories for which CARB has 

primary responsibility for reducing 

emissions in California include most 

new and existing on- and off-road 

engines and vehicles, motor vehicle 

fuels, and consumer products. 

Given the need for substantial 

emissions reductions from mobile and 

area sources to meet the NAAQS in 

California nonattainment areas, CARB 

has established stringent control 

measures for on-road and off-road 

mobile sources and the fuels that power 

them. California has authority under 

CAA section 209 (subject to a waiver by 

the EPA) to adopt and implement new 

emission standards for many categories 

of on-road vehicles and engines, and 

new and in-use off-road vehicles and 

engines. 

CARB’s mobile source program 

extends beyond regulations that are 

subject to the waiver or authorization 

process set forth in CAA section 209 to 

include standards and other 

requirements to control emissions from 

in-use heavy-duty trucks and buses, 

gasoline and diesel fuel specifications, 

and many other types of mobile sources. 

Generally, these regulations have been 

submitted and approved as revisions to 

the California SIP.54

CARB’s Consumer Products Program 

has established regulations that limit 

VOC emissions from 129 consumer 

product categories, which apply in 

Western Nevada County.55 The EPA has 

approved many CARB measures into the 

California SIP that limit VOC emissions 

from a wide array of products, including 

antiperspirants and deodorants, aerosol 

coating products, and other consumer 

products.56

CARB’s RACM analysis determines 

that, with the current mobile source 

program and proposed measures, there 

are no additional RACM that would 

advance attainment of the 2008 ozone 

NAAQS in Western Nevada County. As 

a result, CARB concludes that 

California’s mobile source programs 

fully meet the RACM requirement.57

3. The EPA’s Review of the State’s 

Submission 

As described above and in our 

December 3, 2020 memorandum to file 

in the docket for this proposed action, 

the District has implemented rules to 

reduce VOC and NOX emissions from 

stationary sources in the Western 

Nevada nonattainment area. For the 

2018 Western Nevada County Ozone 

Plan, the District indicates that its ozone 

precursor control strategy focuses on 

NOX emission reductions due to the 

NOX-limited nature of the 

nonattainment area.58

The District evaluated a range of 

potentially available measures and was 

unable to find a combination of 

potential additional control measures 

for RACM. The EPA further calculated 

the additional reductions that would be 

necessary to advance attainment by a 

year. Subtracting the District’s 2020 

attainment year emissions inventory 

from the 2019 emissions inventory 

yields a difference of 0.21 tpd NOX and 

0.075 tpd VOC, equivalent to the 

reductions needed to advance 

attainment by a year.59 Based on our 

review of the District’s analysis, we 

agree that no additional control 

measures are available for stationary 

and area source categories in the 

nonattainment area that would provide 

the emissions reductions needed to 

advance attainment by a year. 

With respect to mobile sources, 

CARB’s current program addresses the 

full range of mobile sources in the 

Western Nevada County nonattainment 

area through regulatory programs for 

both new and in-use vehicles. With 

respect to TCMs, we find that the TCMs 

being implemented in Western Nevada 

County (i.e., the TCMs described in the 

Transportation Plan) are inclusive of all 

TCM RACM to be reasonably justified 

and supported. 

We also find that CARB’s consumer 

products program comprehensively 

addresses emissions from consumer 

products in the Western Nevada County 

nonattainment area. CARB measures are 

more stringent than the EPA’s consumer 

products regulation promulgated in 

1998,60 and generally exceed the 

controls in place throughout other areas 

of the country. 

Based on our review of these RACM 

analyses and the District’s and CARB’s 

adopted rules, we propose to find that 

there are, at this time, no additional 

RACM (including RACT) that would 

advance attainment of the 2008 ozone 

NAAQS in Western Nevada County. For 

the foregoing reasons, we propose to 

find that the 2018 Western Nevada 


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61 77 FR 30088 (May 21, 2012). 

62 81 FR 26697 (April 4, 2015). 

63 84 FR 44238 (August 23, 2019). 

64Nine years after the initial designation, 84 FR 

44244. 

65 ‘‘Modeling Guidance for Demonstrating 

Attainment of Air Quality Goals for Ozone, PM2.5, 

and Regional Haze,’’ EPA 454/R–18–009, EPA 

OAQPS, November 2018; available at https://

www.epa.gov/scram/state-implementation-plan-sipattainment-demonstration-guidance. See also 

December 2014 draft of this guidance, available at 

https://www3.epa.gov/ttn/scram/guidance/guide/ 

Draft-O3-PM-RH-Modeling_Guidance-2014.pdf. The 

December 2014 draft guidance was available during 

development of the Plan; the final version differs 

mainly in organization, and in updates to the 

regional haze portion and to other document 

references. Additional EPA modeling guidance can 

be found in 40 CFR 51 Appendix W, Guideline on 

Air Quality Models, 82 FR 5182 (January 17, 2017); 

available at https://www.epa.gov/scram/clean-airact-permit-modeling-guidance. 

66Modeling Guidance section 2.7.1, 35. 

67 Id. 

68See also CAA section 110(a)(2)(A). 

69 40 CFR 51.1108(d). 

70 40 CFR 51.1100(h). 

71 ‘‘Staff Report: CARB Review of the Ozone 

Attainment Plan for Western Nevada County,’’ 

CARB, October 12, 2018. 

72CARB Staff Report, 2 and 20. 

73The summer 2020 emissions inventories for the 

Sacramento nonattainment area and Western 

Nevada Nonattainment NOX are 63.2 and 3.1 tpd, 

respectively; VOC emissions are 86.8 and 4.3 tpd, 

respectively, 2018 Western Nevada County Ozone 

Plan, E–27. The 2020 Sacramento County 

population is 1,543,522, about 14 times the size of 

the Nevada County population of 104,343, Almanac 

of Emissions & Air Quality, California Air 

Resources Board, 2013, Appendix C, available at 

https://ww2.arb.ca.gov/our-work/programs/ 

resource-center/technical-assistance/air-qualityand-emissions-data/almanac. 

County Ozone Plan provides for the 

implementation of all RACM as required 

by CAA section 172(c)(1) and 40 CFR 

51.1112(c). 

D. Attainment Demonstration 

1. Statutory and Regulatory 

Requirements 

Section 182(c)(2)(A) of the CAA 

requires that a plan for an ozone 

nonattainment area classified Serious or 

above include a ‘‘demonstration that the 

plan . . . will provide for attainment of 

the ozone [NAAQS] by the applicable 

attainment date. This attainment 

demonstration must be based on 

photochemical grid modeling or any 

other analytical method determined 

. . . to be at least as effective.’’ The 

attainment demonstration predicts 

future ambient concentrations for 

comparison to the NAAQS, making use 

of available information on measured 

concentrations, meteorology, and 

current and projected emissions 

inventories of ozone precursors, 

including the effect of control measures 

in the Plan. 

Areas classified Serious for the 2008 

ozone NAAQS must demonstrate 

attainment as expeditiously as 

practicable, but no later than 9 years 

after the effective date of designation as 

nonattainment. Western Nevada County 

was designated as a Marginal 

nonattainment area for the 2008 ozone 

NAAQS effective July 20, 2012.61 It was 

subsequently reclassified to Moderate,62

and then to Serious,63 and accordingly 

must demonstrate attainment of the 

standards by no later than July 20, 

2021.64 An attainment demonstration 

must show attainment of the standards 

for a full calendar year before the 

attainment date, so in practice, Serious 

nonattainment areas must demonstrate 

attainment for the attainment year 2020. 

The EPA’s recommended procedures 

for modeling ozone as part of an 

attainment demonstration are contained 

in ‘‘Modeling Guidance for 

Demonstrating Attainment of Air 

Quality Goals for Ozone, PM2.5, and 

Regional Haze’’ (‘‘Modeling 

Guidance’’).65 The Modeling Guidance 

includes recommendations for a 

modeling protocol, model input 

preparation, model performance 

evaluation, use of model output for the 

numerical NAAQS attainment test, and 

modeling documentation. Air quality 

modeling is performed using 

meteorology and emissions from a base 

year, and the predicted concentrations 

from this base case modeling are 

compared to air quality monitoring data 

from that year to evaluate model 

performance. Once the model 

performance is determined to be 

acceptable, future year emissions are 

simulated with the model. The relative 

(or percent) change in modeled 

concentration due to future emissions 

reductions provides a relative response 

factor (RRF). Each monitoring site’s RRF 

is applied to its monitored base year 

design value to give the future design 

value for comparison to the NAAQS. 

The Modeling Guidance also 

recommends supplemental air quality 

analyses, which may be used as part of 

a weight of evidence (WOE) analysis. A 

WOE analysis corroborates the 

attainment demonstration by 

considering evidence other than the 

main air quality modeling attainment 

test, such as trends and additional 

monitoring and modeling analyses. 

Unlike the RFP demonstration and the 

emissions inventory requirements, the 

2008 SRR does not specify that a 

specific year must be used for the 

modeled base year for the attainment 

demonstration. The Modeling Guidance 

also does not require a particular year to 

be used as the base year for 8-hour 

ozone plans.66 The Modeling Guidance 

states that the most recent year of the 

National Emissions Inventory may be 

appropriate for use as the base year for 

modeling, but that other years may be 

more appropriate when considering 

meteorology, transport patterns, 

exceptional events, or other factors that 

may vary from year to year.67 Therefore, 

the base year used for the attainment 

demonstration need not be the same 

year used to meet the requirements for 

emissions inventories and RFP. 

With respect to the list of adopted 

measures, CAA section 172(c)(6) 

requires that nonattainment area plans 

include enforceable emissions 

limitations, and such other control 

measures, means or techniques 

(including economic incentives such as 

fees, marketable permits, and auctions 

of emission rights), as well as schedules 

and timetables for compliance, as may 

be necessary or appropriate to provide 

for timely attainment of the NAAQS.68

Under the 2008 Ozone SRR, all control 

measures needed for attainment must be 

implemented no later than the 

beginning of the attainment year ozone 

season.69 The attainment year ozone 

season is defined as the ozone season 

immediately preceding a nonattainment 

area’s maximum attainment date; 70 in 

the case of the Western Nevada County 

area, the attainment year is 2020. 

2. Summary of the State’s Submission 

a. Photochemical Modeling 

CARB performed the air quality 

modeling for the Western Nevada Ozone 

Plan, and has included documentation 

of this modeling within the Plan and the 

Staff Report that accompanied CARB’s 

submittal of the 2018 Ozone Plan 

(‘‘CARB Staff Report’’).71 The modeling 

relies on a 2012 base year and projects 

design values for 2020. The Plan’s 

modeling protocol is in Appendix H of 

the 2018 Western Nevada County Ozone 

Plan and contains all the elements 

recommended in the Modeling 

Guidance, with the exception of a 

conceptual description and a WOE 

analysis, which appear in the CARB 

Staff Report.72 The area is dominated by 

transport of ozone and precursors from 

the Sacramento Metro nonattainment 

area, which has a much higher 

population and emissions about twenty 

times larger.73 Concentrations at 

Western Nevada County’s single 

monitor, Grass Valley, have paralleled 

those in the eastern portions of the 

Sacramento area for the past two 

decades. The Western Nevada County 

area has multiple valleys extending 

from southwest to northeast into the 

higher elevations of the Sierra Nevada 

mountain range. Upslope-downslope 


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74Ozone is generally NOX-limited in rural areas 

and downwind suburban areas. See pages 24 and 

38 of CARB Staff Report and also Chapter 2.1 Ozone 

Chemistry, ‘‘Final Ozone NAAQS Regulatory 

Impact Analysis,’’ March 2008, EPA Office of Air 

Quality Planning and Standards, available at 

https://www3.epa.gov/ttnecas1/regdata/RIAs/452_

R_08_003.pdf. The term ‘‘NOX-limited’’ can mean 

either that reducing NOX emissions decrease ozone 

(as opposed to increasing it); or that reducing NOX

is much more effective at decreasing ozone than is 

reducing VOC. As discussed below and on page 42 

of CARB Staff Report, ozone in Western Nevada 

County are decreased by reducing NOX emissions. 

75 2018 Western Nevada Ozone Plan, page H–16. 

76Appendix E, section 3.2, E–17; also, refer to 

supplemental figures S.1–S.11, E–48. 

77Appendix E, section 5.2, E–32; also, refer to 

supplemental figures S.12–S.16, E–55. 

78Because only the relative response to emissions 

changes (RRF) from the modeling is used, the 

underprediction of absolute ozone concentrations 

does not mean that future concentrations will be 

underestimated. 

79Simon, H., Baker, K.R., Phillips, S, 2012, 

Compilation and Interpretation of Photochemical 

Model Performance Statistics Published Between 

2006 and 2012, Atmos. Environ., 61, 124–139. 

doi:10.1016/j.atmosenv.2012.07.012. 

80 2018 Western Nevada County Ozone Plan, 

Appendix H, ‘‘Modeling Protocol,’’ H–31; Modeling 

Guidance, 63. 

81See ‘‘Diagnostic Evaluation’’ in Appendix E 

section 5.2.1, E–36. 

82 2018 Western Nevada County Ozone Plan, 

Appendix E, E–40. 

83 Id. at 57, and Appendix H, ‘‘Modeling 

Protocol,’’ section 10.3, H–34. 

flows in those valleys lead to 

recirculation of pollutants, and the 

Sierra crest tends to block flow further 

east; both of these enhance ozone 

concentrations. The area is mainly rural, 

with generally low NOX emissions and 

relatively high VOC emissions, so that 

ozone formation there is expected to be 

NOX-limited.74 The recirculation and 

the lack of NOX emissions prevents the 

removal of ozone through the NOX

titration process. This allows carryover 

of pollution from the previous day, 

leading to high ozone values that persist 

through the night at the start of the 

following morning, unlike the typical 

pattern for areas with ozone caused by 

locally generated emissions.75

The modeling and the modeled 

attainment demonstration are described 

in Chapter XII of the 2018 Western 

Nevada County Ozone Plan and in more 

detail in Appendix E, which provides a 

description of model input preparation 

procedures and various model 

configuration options. Appendix F of 

the 2018 Western Nevada County Ozone 

Plan provides the coordinates of the 

modeling domain and thoroughly 

describes the development of the 

modeling emissions inventory, 

including its chemical speciation, its 

spatial and temporal allocation, its 

temperature dependence, and quality 

assurance procedures. The modeling 

analysis uses version 5 of the 

Community Multiscale Air Quality 

(CMAQ) photochemical model 

developed by the EPA, using the 2007 

version of the Statewide Air Pollution 

Research Center (SAPRC07) chemical 

mechanism. The CMAQ modeling 

domain covers most of California, 

nested within a domain covering the 

entire state. To prepare meteorological 

inputs for CMAQ, CARB used the 

Weather and Research Forecasting 

model version 3.6 (WRF) from the 

National Center for Atmospheric 

Research. The WRF domain covers the 

entire state of California, nested within 

a domain covering most of the western 

United States. The modeling used 

inputs prepared from routinely available 

meteorological and air quality data 

collected during 2012. Those data cover 

May through September, a period that 

spans the period of highest ozone 

concentrations in Western Nevada 

County. The Modeling Guidance 

recognizes both CMAQ and WRF as 

technically sound, state-of-the-art 

models. The areal extent and the 

horizontal and vertical resolution used 

in these models is adequate for 

modeling Western Nevada County 

ozone. 

The WRF meteorological model 

results and performance statistics are 

described in Appendix E.76 The 

performance evaluation focuses on a 

smaller area than the full domain but 

encompassing the Western Nevada 

County nonattainment area and the 

greater Sacramento area, with special 

attention on the winds for high ozone 

days. There is a slight overprediction of 

wind speeds and underprediction of 

temperatures in the eastern portion of 

the nonattainment area, but overall, 

modeled wind speed, wind direction, 

and temperature all track observations 

very well, as shown in scatter and time 

series plots. The modeling replicates 

some important meteorological features 

such as the upslope-downslope flows in 

the Sierra Nevada foothills, and the 

‘‘Schulz eddy’’ known to occur in the 

greater Sacramento area. The 2018 

Western Nevada County Ozone Plan 

states that the bias and error are 

relatively small and are comparable to 

those seen in previous meteorological 

modeling of central California and cited 

in the Plan. In summary, the 2018 

Western Nevada County Ozone Plan’s 

meteorological modeling performance 

statistics appear satisfactory. 

Ozone model performance statistics 

are described in the 2018 Western 

Nevada County Ozone Plan at Appendix 

E.77 Appendix E includes tables of 

statistics recommended in the Modeling 

Guidance for 8-hour and 1-hour daily 

maximum ozone concentrations. 

Predicted concentrations have a small 

negative bias (underprediction) of 4.1 

ppb.78 This compares well to the range 

of 2.7 to 10.8 ppb seen in a previous 

modeling exercise for central California 

that is cited in the Plan; bias and error 

are both at the low end of those seen in 

a comparative study of 69 modeling 

exercises.79 The Plan’s supplemental 

figures with hourly time series show 

good performance; although some 

individual daily ozone peaks are missed 

in May and September, there are days 

for which the modeled highest 

concentration is close to the value of the 

highest observed concentration. This 

supports the adequacy of the model for 

use in the attainment demonstration. 

As noted in the 2018 Western Nevada 

County Ozone Plan’s modeling protocol, 

the Modeling Guidance recognizes that 

limited time and resources can 

constrain the extent of the diagnostic 

and dynamic evaluation of model 

performance undertaken.80 The Plan 

describes a dynamic evaluation 81 in 

which model predictions of ozone 

concentrations for weekdays and 

weekends were compared to each other 

and to observed concentrations. This 

evaluation provides useful information 

on how well the model simulates the 

effect of emissions changes, since NOX

emissions are lower on weekends than 

on weekdays, but the days are otherwise 

similar. The modeled ozone decreased 

in response to the weekend NOX

reductions, which matches the observed 

decrease, and indicates that the model 

is simulating the chemistry correctly. 

The Plan also contains results of an 

analysis of weekday and weekend ozone 

concentrations during the 2000–2015 

period. It notes a shift over the years 

toward lower ozone on weekends, 

especially after 2010, showing that 

lower NOX emissions lead to lower 

ozone concentrations.82 Both the 

modeling and the observed weekdayweekend trends show that ozone 

responds to NOX emissions reductions, 

i.e., that ozone formation is NOXlimited. The modeled 2012 base year is 

also NOX-limited, with the weekdayweekend difference comparable to those 

seen historically. This match lends 

confidence to the modeling. 

After accepting the model 

performance for the 2012 base case, 

CARB used the model to develop RRFs 

for the attainment demonstration.83 This 

entailed running the model with the 

same meteorological inputs as before, 

but with emissions inventories to reflect 


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84 Id. at Appendix H, H–33; and, Appendix F, 

‘‘Modeling Emissions Inventory,’’ F–35. To include 

the fires in the base year but not the future year 

would effectively credit the Plan’s control measures 

with eliminating emissions from the fire. 85 Id. at 57, and Appendix H, ‘‘Modeling 

Protocol,’’ section 10.3, H–34. The combination of 

years used is illustrated in Appendix E, Table 1, 

E–11. 

86The Modeling Guidance recommends that 

RRFs be applied to the average of three three-year 

design values, for the base year and the two 

subsequent years. This amounts to a 5-year 

weighted average of individual year 4th high 

concentrations, centered on the base year, and so 

is referred to as a weighted design value. 87 2018 Western Nevada County Ozone Plan, 

Appendix E, E–10; also Plan, 58. 

88 2018 Western Nevada County Ozone Plan, 

Appendix E, section 5.4, E–41. 

89Modeling Guidance section 4.7, 138. 

90The R Project for Statistical Computing, https:// 

www.r-project.org. 

91 2018 Western Nevada County Ozone Plan, page 

41. 

the expected changes between the 2012 

base year and the 2020 future year. 

These modeling inventories exclude 

‘‘emissions events which are either 

random and/or cannot be projected to 

the future . . . wildfires, and events 

such as the [San Francisco Bay Area] 

Chevron refinery fire.’’ 84 The future 

inventories project the base year with 

these exclusions into the future by 

including the effect of economic growth 

and emissions control measures. 

The 2018 Western Nevada County 

Ozone Plan carries out the attainment 

test procedure consistent with the 

Modeling Guidance. The RRF is 

calculated as the ratio of future to base 

year concentrations; these are then 

applied to the 2013 weighted design 

values for the Grass Valley monitor to 

arrive at a future year design value.85

Typically the RRFs would be applied to 

a weighted design value for 2012, the 

model base year,86 but in this case 

CARB used the somewhat higher value 

for 2013, considering the upward trend 

design values starting in 2013.87 The 

predicted 2020 ozone design value is 67 

ppb or 0.067 ppm, well below the level 

of the 2008 8-hour ozone NAAQS of 

0.075 ppm. 

Finally, the 2018 Western Nevada 

County Ozone Plan modeling includes 

an ‘‘Unmonitored Area Analysis’’ (UAA) 

to assess whether locations without a 

monitor are able to reach attainment; the 

standard attainment test procedure 

covers only locations with a monitor.88

The Modeling Guidance describes a 

procedure utilizing ‘‘gradient adjusted 

spatial fields,’’ as well as the EPA 

software used to carry it out.89 This 

procedure uses a form of interpolation, 

combining monitored concentrations 

and modeled gradients (modeled 

changes in concentration with distance 

from a monitor) to estimate future 

concentrations at locations without a 

monitor. The 2018 Western Nevada 

County Ozone Plan describes a UAA 

carried out using software developed by 

CARB and implemented in ‘‘R,’’ 90 using 

a procedure virtually the same as that 

outlined in the Modeling Guidance. The 

Plan states that the 2020 results show 

concentrations below 75 ppb at all 

locations in the nonattainment area; it 

did not examine the surrounding area. 

Because the results are well below the 

2008 ozone NAAQS level of 75 ppb, the 

UAA supports the demonstration that 

all locations in Western Nevada County 

will attain the NAAQS in 2020. 

In addition to the formal attainment 

demonstration, the Plan also contains a 

WOE analysis within Appendix A to the 

CARB Staff Report. It mainly shows the 

long-term downward trends that 

continue through 2017, the latest year 

available prior to development of the 

2018 Western Nevada County Ozone 

Plan. As described in the WOE, Western 

Nevada County has shown a general 

downward trend in measured ozone 

concentrations and number of days 

above the ozone NAAQS but has 

recently seen increases in 2017 and 

2018. Atypical high ozone 

concentrations were observed in 2017, 

though CARB’s staff analysis does not 

point to specific anthropogenic or 

biogenic emission increases or 

meteorology as likely causes for the 

unusual number of exceedances. 

Additionally, the area may have 

experienced higher than normal ozone 

concentrations in 2018 due to wildfire 

impacts in the surrounding areas during 

the summer and fall months. Despite the 

recent exceptions, there are strong 

downward trends in emissions of ozone 

and of the ozone precursors NOX and 

VOC, both within the Western Nevada 

County area and in the upwind 

Sacramento and San Francisco Bay 

areas.91 These all show the substantial 

air quality progress made in the Western 

Nevada County Area and add support to 

the attainment demonstration for 2020. 

b. Control Strategy 

The control strategy for attainment of 

the 2008 ozone NAAQS is detailed in 

Chapter IV of the 2018 Western Nevada 

County Ozone Plan. The Plan’s strategy 

relies primarily on emissions reductions 

from control measures that have been 

adopted by the Districts and CARB prior 

to the submittal of the Plan. The District 

has adopted rules for reducing 

emissions from a broad scope of 

stationary and area sources into its 

RACT SIP. Additionally, a detailed 

description of the mobile source control 

programs and a comprehensive list of 

CARB regulations are included in 

Appendices B and C of the Plan. CARB’s 

comprehensive strategy to reduce 

emissions from mobile sources consists 

of emissions standards for new vehicles, 

in-use programs to reduce emissions 

from existing vehicle and equipment 

fleets, cleaner fuels, and incentive 

programs to accelerate the penetration 

of the cleanest vehicles beyond that 

achieved by regulations alone. 

As Table 2 and Table 3 show, the vast 

majority of emissions reductions relied 

upon by the Plan’s control strategy are 

from the on- and off-road mobile source 

inventory and can be largely attributed 

to control measures adopted by CARB, 

subsequently approved by the EPA, and 

cited in detail in Section III.C. 

Generally, the bulk of the emissions 

reductions on which the control 

strategies rely is expected to come from 

already-adopted measures, which are 

discussed in Section III.C of this 

document. For the 2008 ozone NAAQS, 

already-adopted measures are expected 

to achieve all of the reductions needed 

from the 2012 base year to attain the 

NAAQS in 2020. 

TABLE 2—2012 AND 2020 NOX EMISSIONS FOR WESTERN NEVADA COUNTY

[Summer planning inventory, tpd] 

Source category 2012 2020 

Emissions 

difference from 

2012 to 2020 

Percentage of total 

emissions change 

(%) 

Stationary Sources ........................................................................ 0.106 0.096 ¥0.010 ¥9.4 

Area Sources ................................................................................. 0.135 0.138 +0.003 2.2 

On-Road Mobile Sources .............................................................. 3.976 2.160 ¥1.816 ¥45.7 

Other Mobile Sources .................................................................... 0.944 0.738 ¥0.206 ¥21.8 


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92Modeling Guidance, section 4.1.1, 

‘‘Establishing the Base Design Value,’’ 103. 

93Modeling Guidance, section 3.1, ‘‘Overview of 

Model Performance Evaluation,’’ 68. 

94 Docket EPA–R09–OAR–2020–0425, item A–85, 

‘‘Modeling Technical Support Document (TSD) for 

the ‘2017 Sacramento Regional Ozone Plan’, 2008 

8-hour ozone National Ambient Air Quality 

Standard,’’ September 14, 2020, Air and Radiation 

Division, EPA Region IX. 

TABLE 2—2012 AND 2020 NOX EMISSIONS FOR WESTERN NEVADA COUNTY—Continued 

[Summer planning inventory, tpd] 

Source category 2012 2020 

Emissions 

difference from 

2012 to 2020 

Percentage of total 

emissions change 

(%) 

Total ........................................................................................ 5.160 3.131 ¥2.029 ¥39.3 

Source: 2018 Western Nevada County Ozone Plan, Chapter XII, Table 11, 57. The sum of the emissions values may not equal the total 

shown due to rounding. 

TABLE 3—2012 AND 2020 ANTHROPOGENIC VOC EMISSIONS FOR WESTERN NEVADA COUNTY

[Summer planning inventory, tpd] 

Source category 2012 2020 

Emissions 

difference from 

2012 to 2020 

Percentage of total 

emissions change 

(%) 

Stationary Sources ........................................................................ 0.702 0.785 +0.083 11.8 

Area Sources ................................................................................. 1.394 1.515 +0.121 8.7 

On-Road Mobile Sources .............................................................. 1.793 1.007 ¥0.786 ¥43.8 

Other Mobile Sources .................................................................... 1.327 0.958 ¥0.369 ¥27.8 

Total ........................................................................................ 5.215 4.265 ¥0.950 ¥18.2 

Source: 2018 Western Nevada County Ozone Plan, Chapter XII, Table 11, 57. The sum of the emissions values may not equal the total 

shown due to rounding. 

c. Attainment Demonstration 

Chapter XII of the Plan describes the 

attainment demonstration in general 

terms, including photochemical 

modeling results, while Appendix E to 

the Plan provides more detail 

concerning photochemical modeling. 

Other aspects of this demonstration are 

included throughout the Plan, including 

emissions inventory forecasts included 

in Appendix A and the control strategy 

described in Chapter IV. The WOE 

analysis in Appendix A to the CARB 

Staff Report includes additional 

supporting information to complement 

the photochemical modeling and to 

provide context for this attainment 

demonstration, such as analyses of 

anthropogenic emissions, ambient 

ozone data, and meteorological 

analyses. 

3. The EPA’s Review of the State’s 

Submission 

a. Photochemical Modeling 

To approve a SIP’s attainment 

demonstration, the EPA must make 

several findings. First, we must find that 

the demonstration’s technical bases, 

including the emissions inventories and 

air quality modeling, are adequate. As 

discussed above in Section III.A of this 

document, we are proposing to approve 

the base year emissions inventory and to 

find that the future year emissions 

projections in the 2018 Western Nevada 

County Ozone Plan reflect appropriate 

calculation methods and that the latest 

planning assumptions are properly 

supported by SIP-approved stationary 

and mobile source measures. 

The modeling followed the Modeling 

Guidance in essentially all respects, and 

both the meteorological and the 

photochemical models showed good 

performance. One difference between 

CARB’s modeling and the Modeling 

Guidance was that the state applied 

RRFs to a weighted design value based 

on the year 2013, instead of 2012, as 

would be typical for modeling of a 2012 

base year. The Modeling Guidance 

recognizes that there is no one correct 

method for choosing base design 

values,92 and provides for other 

calculations with appropriate 

justification, such as consideration of 

unusual meteorological conditions. As 

noted above, the state’s choice of 2013 

was based on design values increasing 

relative to 2012. Since a higher starting 

point base design value will yield a 

higher 2020 attainment year design 

value, the state’s use of 2013 adds 

conservatism to the attainment 

demonstration. 

An important difference from the 

Modeling Guidance is that the state 

presented a model performance 

evaluation only for the single 

monitoring site in the nonattainment 

area, in Grass Valley. The Modeling 

Guidance recommends a performance 

evaluation using all available ambient 

monitoring data.93 This is of particular 

importance for the Western Nevada 

County area. As described in the 

conceptual description in the Plan 

discussed above, ozone in the area is 

largely due to emissions in and 

transport from the upwind Sacramento 

area. The chemical evolution of the 

pollutant plume as it travels from 

Sacramento to Nevada County 

necessitates evaluation at more than a 

single downwind location. This means 

that the submitted modeling 

performance evaluation alone may not 

be adequate for assessing the 

performance model, which is influenced 

by emissions from a much larger area, 

with various meteorological and terrain 

impacts. However, because the 2012 

modeling exercise in the Plan was 

essentially the same as that undertaken 

for the 2017 Sacramento Regional Ozone 

Plan, the EPA is relying on the latter 

plan’s more complete model 

performance evaluation. As discussed in 

the technical support document 94

accompanying the EPA’s proposed 

action on the Sacramento plan, the state 

followed EPA recommended modeling 

procedures and the modeling had good 

performance. That was shown in 

statistical and dynamic performance 

analyses that covered a larger portion of 

the modeling domain than the analyses 

in the submittal for the 2018 Western 

Nevada County Ozone Plan, 

encompassing the Western Nevada 

County as well as the Sacramento area. 

Overall, the EPA therefore considers the 

modeling in the 2018 Western Nevada 


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95 40 CFR 51.1110(a)(2)(i)(C) and 40 CFR 

51.1110(a)(2)(ii)(B); and 70 FR 12264, at 12271 

(March 6, 2015). 

96 70 FR 12264, 12271 (March 6, 2015). For more 

information about how the RFP requirement of 

section 172(c)(2) applies in such areas, see 84 FR 

28132, 28157 (June 17, 2019). 

97As explained above in Section I, for the 1979 

1-hour ozone NAAQS, the EPA classified Western 

Nevada County as Unclassifiable/Attainment and, 

thus, it was not subject to the ROP requirement. 62 

FR 38856 (July 18, 1997). For the 1997 8-hour ozone 

NAAQS, the EPA initially designated Western 

Nevada County as a ‘‘Subpart 1’’ nonattainment 

area and later reclassified the area to Moderate, 

triggering the ROP requirement, but subsequently 

issued a clean data determination, which 

suspended attainment-related planning 

requirements, including the ROP requirement. 69 

FR 23857 (April 30, 2004); 77 FR 28423 (May 14, 

2012); 77 FR 71551 (December 3, 2012). 

98 40 CFR 51.1110(a)(7). 

99See 40 CFR 51.1110(b). 

County Ozone Plan to be adequate for 

establishing modeling performance. 

The modeling shows that existing 

control measures from CARB and the 

Districts are sufficient to attain the 2008 

8-hour ozone NAAQS by 2020 at all 

monitoring sites in the Western Nevada 

County area. The Plan follows the 

procedures recommended in the EPA 

Modeling Guidance, properly 

incorporates all modeling and input 

preparation procedures, tests, and 

performance analyses called for in the 

modeling protocol, demonstrates good 

model performance, and responds to 

emission changes consistent with 

observations. Therefore, based on the 

documentation included in the 

modeling performance analysis, UAA, 

and WOE analysis, the EPA finds that 

the photochemical modeling is adequate 

for purposes of supporting the 

attainment demonstration. 

b. Control Strategy 

As discussed above, the 2018 Western 

Nevada County Ozone Plan relies on 

previously adopted measures to achieve 

all of the emissions reductions needed 

to attain the 2008 ozone NAAQS in 

2020. For the reasons described above, 

we find that the emissions reductions 

that are relied on for attainment are 

creditable and are sufficient to provide 

for attainment. 

c. Attainment Demonstration 

The 2018 Western Nevada County 

Ozone Plan follows the modeling 

procedures recommended in the EPA’s 

Modeling Guidance and shows excellent 

performance in simulating observed 

ozone concentrations in the 2012 base 

year. Given the extensive discussion of 

modeling procedures, tests, and 

performance analyses called for in the 

modeling protocol, the good model 

performance, and the model response to 

emissions changes consistent with 

observations, the EPA finds that the 

modeling is adequate for purposes of 

supporting the attainment 

demonstration. Based on our review of 

the 2018 Western Nevada County Ozone 

Plan and our proposed findings that the 

photochemical modeling and control 

strategy are acceptable and demonstrate 

attainment by the applicable attainment 

date, we propose to approve the 

attainment demonstration for the 2008 

ozone NAAQS in the Western Nevada 

County Ozone Plan as meeting the 

requirements of CAA section 

182(c)(2)(A) and 40 CFR 51.1108. 

E. Rate of Progress Plan and Reasonable 

Further Progress Demonstration 

1. Statutory and Regulatory 

Requirements 

Requirements for RFP for ozone 

nonattainment areas are specified in 

CAA sections 172(c)(2), 182(b)(1), and 

182(c)(2)(B). CAA section 172(c)(2) 

requires that plans for nonattainment 

areas provide for RFP, which is defined 

at CAA section 171(1) as such annual 

incremental reductions in emissions of 

the relevant air pollutant as are required 

under part D, ‘‘Plan Requirements for 

Nonattainment Areas,’’ or may 

reasonably be required by the EPA for 

the purpose of ensuring attainment of 

the applicable NAAQS by the applicable 

date. CAA section 182(b)(1) specifically 

requires that ozone nonattainment areas 

that are classified as Moderate or above 

demonstrate a 15 percent reduction in 

VOC within the first six years of the 

planning period. The EPA has typically 

referred to section 182(b)(1) as the Rate 

of Progress (ROP) requirement. For 

ozone nonattainment areas classified as 

Serious or higher, section 182(c)(2)(B) 

requires reductions averaged over each 

consecutive 3-year period, beginning 6 

years after the baseline year until the 

attainment date, of at least 3 percent of 

baseline emissions per year. CAA 

section 182(c)(2)(B)(ii) allows an 

amount less than 3 percent of such 

baseline emissions each year if the state 

demonstrates to the EPA that a plan 

includes all measures that can feasibly 

be implemented in the area in light of 

technological achievability. To meet 

CAA sections 172(c)(2) and 182(c)(2)(B) 

RFP requirements, the state may 

substitute NOX emissions reductions for 

VOC reductions.95

The 2008 Ozone SRR provides that 

areas classified Moderate or higher for 

the 2008 8-hour ozone standard will 

have met the ROP requirements of CAA 

section 182(b)(1) if the area has a fully 

approved 15 percent ROP plan for the 

1979 1-hour or 1997 8-hour ozone 

standards, provided the boundaries of 

the ozone nonattainment areas are the 

same.96 Western Nevada County does 

not have a fully approved 15 percent 

ROP plan for either the 1979 1-hour or 

the 1997 8-hour ozone standards.97

Therefore, the 15 percent ROP 

requirement of section 182(b)(1) remains 

applicable to Western Nevada County, 

and the area must show a 15 percent 

reduction in VOC within the first six 

years of the planning period. 

Except as specifically provided in 

CAA section 182(b)(1)(C), emissions 

reductions from all SIP-approved, 

federally promulgated, or otherwise SIPcreditable measures that occur after the 

baseline year are creditable for purposes 

of demonstrating that the RFP targets are 

met. Because the EPA has determined 

that the passage of time has caused the 

effect of certain exclusions to be de 

minimis, the RFP demonstration is no 

longer required to calculate and 

specifically exclude reductions from 

measures related to motor vehicle 

exhaust or evaporative emissions 

promulgated by January 1, 1990; 

regulations concerning Reid vapor 

pressure promulgated by November 15, 

1990; measures to correct previous 

RACT requirements; and, measures 

required to correct previous inspection 

and maintenance (I/M) programs.98

The 2008 Ozone SRR requires the RFP 

baseline year to be the most recent 

calendar year for which a complete 

triennial inventory was required to be 

submitted to the EPA. For the purposes 

of developing RFP demonstrations for 

the 2008 ozone NAAQS, the applicable 

triennial inventory year is 2011. As 

discussed previously, the 2008 Ozone 

SRR provided states with the 

opportunity to use an alternative 

baseline year for RFP,99 but this 

provision was vacated by the D.C. 

Circuit in the South Coast II decision. 

2. Summary of the State’s Submission 

Documentation for the Western 

Nevada County RFP baseline and 

milestone emissions inventories is 

found in the 2018 Western Nevada 

County Ozone Plan on pages 21–34, 54– 

56, and in Appendix A. Consistent with 

the South Coast II decision, CARB’s RFP 

demonstration for Western Nevada 

County uses a 2011 RFP baseline 

emissions inventory.100 To develop the 

2011 RFP baseline inventory, CARB 

relied on actual emissions reported from 

industrial point sources for year 2011 

and backcasted emissions from smaller 

stationary sources and area sources from 


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101 2018 Western Nevada County Ozone Plan, 

page 23. 

102See also 40 CFR 51.1110(a)(2)(i)(C) and 40 CFR 

51.1110(a)(2)(ii)(B); and 70 FR 12264, at 12271 

(March 6, 2015). The District’s RFP demonstration 

substitutes NOX reductions for VOC reductions on 

a percentage basis. See EPA, NOX Substitution 

Guidance (December 1993). 

103As discussed above, modeling for the 

Sacramento nonattainment area used a modeling 

domain that encompassed the Western Nevada 

nonattainment area, and was used to create an 

isopleth diagram showing ozone for various levels 

of NOX and VOC emissions. Sacramento Regional 

2008 NAAQS 8-hour Attainment and Reasonable 

Further Progress Plan (‘‘2017 Sacramento Regional 

Ozone Plan’’), July 24, 2017, Appendix B–4, p.B– 

158, Figure 16, available at https://ww2.arb.ca.gov/ 

resources/documents/2017-sacramento-regional2008-8-hour-ozone-attainment-and-furtherreasonable. The EPA used this information to 

estimate the sensitivity of ozone to NOX reductions 

and to VOC reductions, and found NOX reductions 

to be 23 times as effective at reducing ozone as VOC 

reductions, on a tonnage basis, and 13 times as 

effective on a percentage basis. Docket EPA–R09– 

OAR–2020–0425, item A–86, ‘‘Assessment of 

Sacramento Metro NAA Conformity Motor Vehicle 

Emissions Budget Consistency with O3 NAAQS 

Attainment,’’ September 14, 2020, Air and 

Radiation Division, EPA Region IX. 

2012 to 2011 using the same growth and 

control factors used for future years.101

The Plan indicates that the 2012 

inventory base year for modeling and 

the 2011 baseline year inventory for RFP 

are consistent with each other since 

they both use actual emissions for 

stationary sources and the same growth 

profiles. Emissions estimates in the 

baseline emissions inventory reflect 

District and CARB rules submitted to 

the EPA through November 2016. 

The RFP demonstration for Western 

Nevada County for the 2008 ozone 

NAAQS is shown in Table 10 of the 

2018 Western Nevada County Ozone 

Plan, which is reproduced as Table 4 

below. As Western Nevada County is a 

Serious nonattainment area without a 

previously approved ROP plan, the Plan 

demonstrates a reduction in VOC of 15 

percent from baseline emissions within 

six years of the RFP baseline year 

period, consistent with CAA 182(b)(1). 

The Plan shows an additional 3 percent 

reduction of VOC or NOX emissions, 

averaged over each consecutive 3-year 

period until the attainment year. The 

RFP demonstration calculates future 

year VOC targets from the 2011 baseline, 

consistent with CAA 182(c)(2)(B)(i), and 

it substitutes NOX reductions for VOC 

reductions beginning in milestone year 

2020 to meet VOC emission targets as 

allowed under CAA section 

182(c)(2)(C).102 CARB concludes that 

the RFP demonstration meets the 

applicable requirements for each 

milestone year as well as the attainment 

year. 

TABLE 4—2008 OZONE RFP DEMONSTRATION WESTERN NEVADA COUNTY

[Summer planning inventory, tpd or percent] 

VOC 

2011 2017 2020 

Baseline VOC .......................................................................................................................................... 5.50 4.50 4.20 

Required change since 2011 (VOC or NOX), % ..................................................................................... .................... 15 24 

Target VOC level ..................................................................................................................................... .................... 4.7 4.2 

Apparent shortfall (¥)/surplus (+) in VOC .............................................................................................. .................... +0.2 ¥0.1 

Apparent shortfall (¥)/surplus (+) in VOC, % ......................................................................................... .................... +3.2 ¥1.4 

Actual VOC shortfall (¥)/surplus (+), % ................................................................................................. .................... +3.2 ¥1.4 

NOX

2011 2017 2020 

Baseline NOX ........................................................................................................................................... 5.69 3.74 2.89 

Change in NOX since 2011 ..................................................................................................................... .................... 1.95 2.8 

Change in NOX since 2011, % ................................................................................................................ .................... 34 49 

NOX reductions used for VOC substitution through last milestone year, % ........................................... .................... .................... 3.1 

NOX reductions since 2011 available for VOC substitution in this milestone year, % ........................... .................... 34 49 

NOX reductions since 2011 used for VOC substitution in this milestone year, % ................................. .................... 0 3.1 

NOX reductions since 2011 surplus after meeting VOC substitution needs in this milestone year, % .. .................... 34 45.9 

Total shortfall for RFP ............................................................................................................................. .................... 0 0 

RFP met? ................................................................................................................................................. .................... Yes Yes 

Source: 2018 Western Nevada County Ozone Plan, Table 10, p. 55. 

3. The EPA’s Review of the State’s 

Submission 

Based on our review of the emissions 

inventory documentation in the 2018 

Western Nevada County Ozone Plan, we 

find that CARB and the District have 

used the most recent planning and 

activity assumptions, emissions models, 

and methodologies in developing the 

RFP baseline and milestone year 

emissions inventories. We have also 

reviewed the calculations in Table 10 of 

the Plan and presented in Table 4 above 

and find that the District and CARB 

have used an appropriate calculation 

method to demonstrate RFP. 

We have also reviewed the 

comparison of the VOC emission 

reductions against the 15 percent ROP 

requirement. As shown in Table 4, the 

RFP demonstration shows that Western 

Nevada County meets the 15 percent 

reduction in VOC emissions with an 

additional 3.2 percent surplus in VOC 

emissions reductions from 2011 to 2017. 

Such reductions satisfy the ROP 

requirement for Western Nevada County 

for the 2008 ozone NAAQS. As a result, 

we find that the District and CARB have 

met the ROP requirements of CAA 

section 182(b)(1) for Western Nevada 

County with respect to the 2008 ozone 

NAAQS. 

We find that the District’s use of 

substitution of NOX reductions for VOC 

reductions in this demonstration is 

appropriate under CAA section 

182(c)(2)(C). As described in Section 

III.D.2.a of this document, ozone 

formation in Western Nevada County is 

NOX-limited, and the substituted NOX

reductions are expected to achieve an 

equal or greater reduction in ozone 

concentrations as would result from the 

VOC emissions reductions described in 

CAA section 182(c)(2)(B).103


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104 70 FR 71612 (November 29, 2005). See also 

2008 Ozone SRR, 80 FR 12264, at 12285 (March 6, 

2015). 

105 80 FR 12264 at 12285 (March 6, 2015). 

106See, e.g., 62 FR 15844 (April 3, 1997) (direct 

final rule approving an Indiana ozone SIP revision); 

62 FR 66279 (December 18, 1997) (final rule 

approving an Illinois ozone SIP revision); 66 FR 

30811 (June 8, 2001) (direct final rule approving a 

Rhode Island ozone SIP revision); 66 FR 586 

(January 3, 2001) (final rule approving District of 

Columbia, Maryland, and Virginia ozone SIP 

revisions); and 66 FR 634 (January 3, 2001) (final 

rule approving a Connecticut ozone SIP revision). 

107See, e.g., LEAN v. EPA, 382 F.3d 575 (5th Cir. 

2004) (upholding contingency measures that were 

previously required and implemented where they 

were in excess of the attainment demonstration and 

RFP SIP). 

108Bahr v. EPA, 836 F.3d 1218, at 1235–1237 (9th 

Cir. 2016). 

109 Id. at 1235–1237. 

110The Bahr v. EPA decision involved a challenge 

to an EPA approval of contingency measures under 

the general nonattainment area plan provisions for 

contingency measures in CAA section 172(c)(9), 

but, given the similarity between the statutory 

language in section 172(c)(9) and the ozone-specific 

contingency measures provision in section 

182(c)(9), we find that the decision affects how both 

sections of the Act must be interpreted. 

111CARB Staff Report, Section D, 10–11. 

112Letter dated October 26, 2020, from Gretchen 

Bennitt, Executive Director, NSAQMD, to Richard 

Corey, Executive Officer, CARB. 

113Appendix to Letter dated October 26, 2020, 

from Gretchen Bennitt, Executive Director, 

NSAQMD, to Richard Corey, Executive Officer, 

CARB. 

For these reasons, we have 

determined that the 2018 Western 

Nevada County Ozone Plan 

demonstrates RFP in each milestone 

year and the attainment year, consistent 

with applicable CAA requirements and 

EPA guidance. We therefore propose to 

approve the RFP demonstrations for the 

Western Nevada County nonattainment 

area for the 2008 ozone NAAQS under 

sections 172(c)(2), 182(b)(1) and 

182(c)(2)(B) of the CAA and 40 CFR 

51.1110(a)(2)(ii). 

F. Contingency Measures 

1. Statutory and Regulatory 

Requirements 

Under the CAA, 8-hour ozone 

nonattainment areas classified under 

subpart 2 as Moderate or above must 

include in their SIPs contingency 

measures consistent with sections 

172(c)(9) and 182(c)(9). Contingency 

measures are additional controls or 

measures to be implemented in the 

event the area fails to make reasonable 

further progress or to attain the NAAQS 

by the attainment date. The SIP should 

contain trigger mechanisms for the 

contingency measures, specify a 

schedule for implementation, and 

indicate that the measure will be 

implemented without significant further 

action by the state or the EPA.104

Neither the CAA nor the EPA’s 

implementing regulations establish a 

specific level of emissions reductions 

that implementation of contingency 

measures must achieve, but the EPA’s 

2008 Ozone SRR reiterates the EPA’s 

policy that contingency measures 

should generally provide for emissions 

reductions approximately equivalent to 

one year’s worth progress, amounting to 

reductions of 3 percent of the baseline 

emissions inventory for the 

nonattainment area.105

It has been the EPA’s longstanding 

interpretation of CAA section 172(c)(9) 

that states may rely on federal measures 

(e.g., federal mobile source measures 

based on the incremental turnover of the 

motor vehicle fleet each year) and local 

measures already scheduled for 

implementation that provide emissions 

reductions in excess of those needed to 

provide for RFP or expeditious 

attainment. The key is that the Act 

requires that contingency measures 

provide for additional emissions 

reductions that are not relied on for RFP 

or attainment and that are not included 

in the RFP or attainment demonstrations 

as meeting part or all of the contingency 

measures requirements. The purpose of 

contingency measures is to provide 

continued emissions reductions while 

the plan is being revised to meet the 

missed milestone or attainment date. 

The EPA has approved numerous SIPs 

under this interpretation, i.e., SIPs that 

use as contingency measures one or 

more federal or local measures that are 

in place and provide reductions that are 

in excess of the reductions required by 

the attainment demonstration or RFP 

plan,106 and there is case law 

supporting the EPA’s interpretation in 

this regard.107 However, in Bahr v. EPA, 

the United States Court of Appeals for 

the Ninth Circuit (‘‘Ninth Circuit’’) 

rejected the EPA’s interpretation of CAA 

section 172(c)(9) as allowing for early 

implementation of contingency 

measures.108 The Ninth Circuit 

concluded that contingency measures 

must take effect at the time the area fails 

to make RFP or attain by the applicable 

attainment date, not before.109 Thus, 

within the geographic jurisdiction of the 

Ninth Circuit, states cannot rely on 

early-implemented measures to comply 

with the contingency measures 

requirements under CAA section 

172(c)(9) and 182(c)(9).110

2. Summary of the State’s Submission 

In the 2018 Western Nevada County 

Ozone Plan, CARB calculates the extent 

of surplus emission reductions (i.e., 

surplus to meeting the RFP milestone 

requirement for a given milestone year) 

in the milestone years and estimates the 

incremental emissions reductions in the 

year following the attainment year.111 In 

light of the Bahr v. EPA decision, 

however, the 2018 Western Nevada 

County Ozone Plan does not rely on the 

surplus or incremental emissions 

reductions to comply with the 

contingency measures requirements of 

sections 172(c)(9) and 182(c)(9) but, 

rather, to provide context in which to 

evaluate the adequacy of Bahrcompliant (i.e., to take effect if triggered) 

contingency measures for the 2008 

ozone NAAQS. 

To comply with sections 172(c)(9) and 

182(c)(9), as interpreted in the Bahr v. 

EPA decision, the state must develop, 

adopt and submit a contingency 

measure to be triggered upon a failure 

to meet RFP milestones or failure to 

attain the NAAQS by the applicable 

attainment date regardless of the extent 

to which already-implemented 

measures would achieve surplus 

emissions reductions beyond those 

necessary to meet RFP milestones and 

beyond those predicted to achieve 

attainment of the NAAQS. Therefore, to 

fully address the contingency measures 

requirement for the 2008 ozone NAAQS 

in the Western Nevada nonattainment 

area, the District has committed to 

develop, adopt and submit a 

contingency measure to CARB in 

sufficient time to allow CARB to submit 

the contingency measure as a SIP 

revision to the EPA within 12 months of 

the EPA’s final conditional approval of 

the contingency measures element of 

the 2018 Western Nevada County Ozone 

Plan.112

The District’s commitment is to adopt 

the 2019 (or most recent) Architectural 

Coatings Suggested Control Measure 

(SCM), developed and approved by 

CARB, as a rule to take effect upon 

adoption throughout the nonattainment 

area upon a determination that the 

Western Nevada County nonattainment 

area failed to meet an RFP milestone or 

failed to attain the 2008 ozone NAAQS 

by the applicable attainment date. The 

District estimates that adoption of this 

new measure will yield an estimated 

0.010 tpd in VOC emissions reductions 

in the nonattainment area. The District 

also evaluated three other additional 

categories for potential contingency 

measures. The categories are automotive 

coatings, water heaters, boilers, and 

process heaters rated less than a million 

BTU per hour, and miscellaneous 

combustion units. However, the District 

determined that these categories did not 

yield meaningful reductions.113

CARB attached the District’s 

commitment to a letter committing 

CARB to adopt and submit the revised 


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114Letter dated November 16, 2020, from Richard 

W. Corey, Executive Officer, CARB, to John 

Busterud, Regional Administrator, EPA Region IX. 

115CAA section 182(g)(2) provides that states 

must submit RFP milestone compliance 

demonstrations within 90 days after the date on 

which an applicable milestone occurs, except 

where the milestone and attainment date are the 

same and the standard has been attained. 

116One year’s worth of RFP for Western Nevada 

County corresponds to 3 percent of the 2011 RFP 

baseline year inventories for VOC (5.496 tpd) and 

NOX (5.687 tpd). 

117Estimates for the emissions reductions in the 

year following the attainment year are based on the 

emissions inventories for Western Nevada County 

in Appendix A of the Plan. The estimate of the 

reductions in emissions of 0.048 tpd of VOC and 

0.23 tpd of NOX in 2021 (relative to 2020) amounts 

to approximately 29 percent and 132 percent of one 

year’s worth of progress, respectively in this area 

based on the 2011 RFP baseline inventory. 

NSAQMD rule to the EPA within one 

year of the EPA’s final conditional 

approval of the contingency measures 

element of the 2018 Western Nevada 

County Ozone Plan.114

3. The EPA’s Review of the State’s 

Submission 

CAA sections 172(c)(9) and 182(c)(9) 

require contingency measures to address 

potential failures to achieve RFP 

milestones or to attain the NAAQS by 

the applicable attainment date through 

implementation of additional emissions 

controls in the event the area fails to 

make RFP or to attain the NAAQS by 

the applicable attainment date. 

Contingency measures must provide for 

the implementation of additional 

emissions controls, if triggered, without 

significant further action by the state or 

the EPA. For the purposes of evaluating 

the adequacy of the emissions 

reductions from the contingency 

measures (once adopted and submitted), 

we find it useful to distinguish between 

contingency measures to address 

potential failure to achieve RFP 

milestones (‘‘RFP contingency 

measures’’) and contingency measures 

to address potential failure to attain the 

NAAQS (‘‘attainment contingency 

measures’’). 

With respect to the RFP contingency 

measures requirement, we have 

reviewed the surplus emissions 

estimates in each of the RFP milestone 

years, as shown in CARB’s Staff Report, 

and find that the calculations are 

correct. We therefore agree that the 2018 

Western Nevada County Ozone Plan 

provides surplus emissions reductions 

well beyond those necessary to 

demonstrate RFP in all of the RFP 

milestone years. While such surplus 

emissions reductions in the RFP 

milestone years do not represent 

contingency measures themselves, we 

believe they are relevant in evaluating 

the adequacy of RFP contingency 

measures that are submitted (or will be 

submitted) to meet the requirements of 

sections 172(c)(9) and 182(c)(9). 

The attainment year for the 2008 

ozone NAAQS in Western Nevada 

County coincides with the 2020 RFP 

milestone, and thus, we have reviewed 

the emissions reductions estimated by 

the District for the committed 

contingency measures in light of the 

facts and circumstances in Western 

Nevada County in the year following the 

attainment year, to determine whether 

there will be sufficient continued 

progress in that area in the event the 

area fails to achieve the 2020 RFP 

milestone or fails to attain the 2008 

ozone NAAQS by the 2020 attainment 

year.115

As discussed above, 2018 Western 

Nevada County Ozone Plan provides 

estimates of emissions reductions that 

are surplus of the reductions necessary 

for RFP or attainment, but does not 

include measures that would implement 

additional emissions controls, if 

triggered, without significant further 

action by the state or the EPA. However, 

CARB and the District have submitted 

commitments to adopt and submit a 

revised District rule with the necessary 

provisions as a SIP revision within one 

year of the EPA’s final action on the 

contingency measures element of the 

Plan. The specific revisions the District 

has committed to make, such as 

tightening control efficiencies or 

establishing content limits, upon a 

failure to achieve a milestone or a 

failure to attain, would comply with the 

requirements in CAA sections 172(c)(9) 

and 182(c)(9) because the additional 

controls would be undertaken if the area 

fails to achieve a milestone or fails to 

attain, and would take effect without 

significant further action by the State or 

the EPA. 

We find that the contingency 

measures described in the District and 

CARB’s commitment letters would 

provide adequate emissions reductions 

when triggered. Neither the CAA nor the 

EPA’s implementing regulations for the 

ozone NAAQS establish a specific 

amount of emissions reductions that 

implementation of contingency 

measures must achieve, but we 

generally expect that contingency 

measures should provide for emissions 

reductions approximately equivalent to 

one year’s worth of RFP, which, for 

ozone, amounts to reductions of 3 

percent of the RFP baseline year 

emissions inventory for the 

nonattainment area. For the 2008 ozone 

NAAQS in Western Nevada County, one 

year’s worth of RFP is approximately 

0.16 tpd of VOC or 0.17 tpd of NOX

reductions.116 The District’s 

commitment letter estimates the 

potential additional emission reductions 

from its contingency measure 

commitment at 0.010 tpd VOC. 

However, emissions in the year 

following the attainment year (2021) in 

Western Nevada County are expected to 

be approximately 0.048 tpd lower for 

VOC and 0.23 tpd lower for NOX than 

in the attainment year (2020).117 The 

downward trend in emissions reflects 

the continuing benefits of alreadyimplemented measures and is primarily 

the result of vehicle turnover, which 

refers to the ongoing replacement by 

individuals, companies, and 

government agencies of older, more 

polluting vehicles and engines with 

newer vehicles and engines. While the 

continuing reductions from such 

already-implemented measures do not 

constitute contingency measures 

themselves, they provide context in 

which we evaluate the adequacy of the 

contingency measures submitted (or, in 

this case, to be submitted) to fulfill the 

requirements of CAA sections 172(c)(9) 

and 182(c)(9). 

In this instance, we find that the 

emissions reductions from the to-beadopted contingency measures together 

with the reductions expected to occur 

due to already-implemented measures 

are consistent with our guidance 

recommending that contingency 

measures provide for one year’s worth 

of progress in the event of a failure to 

meet an RFP milestone or a failure to 

attain the NAAQS by the applicable 

attainment date. Therefore, in light of 

the year-to-year reductions in the VOC 

and NOX inventories, we find that the 

contingency measures described in the 

District’s and CARB’s commitment 

letters would provide sufficient 

emissions reductions even though 

reductions from the measures would be 

lower than the EPA normally 

recommends for such measures. 

For these reasons, and in light of 

commitments from the District and 

CARB to adopt and submit a District 

rule that will apply tighter limits or 

requirements upon a failure to achieve 

an RFP milestone or the 2008 ozone 

NAAQS by the applicable attainment 

date, we propose to approve 

conditionally the contingency measures 

element of the 2018 Western Nevada 

County Ozone Plan as meeting the 

contingency measures requirements of 

CAA sections 172(c)(9) and 182(c)(9). 

Our proposed approval is conditional 

because it relies upon commitments to 

adopt and submit a specific enforceable 


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118As mentioned in Section I.B, Western Nevada 

County is an isolated rural area. Isolated rural areas 

do not have federally required metropolitan 

transportation plans and transportation 

improvement programs, and they are not subject to 

the frequency requirements for conformity 

determinations on transportation plans and 

transportation improvement programs (40 CFR 

93.104(b), (c), and (e)). Instead, in an isolated rural 

area, a conformity determination is required for the 

2008 ozone and other applicable NAAQS only 

when a non-exempt FHWA/FTA project(s) needs 

funding or approval, based on the conformity 

requirements for isolated rural areas at 40 CFR 

93.109(g). See also ‘‘Transportation Conformity 

Guidance for 2008 Ozone Nonattainment Areas,’’ 

July 2012, EPA Office of Transportation and Air 

Quality, Transportation and Climate Division, 

available at https://www3.epa.gov/ttn/naaqs/ 

aqmguide/collection/cp2/20120701_otaq_epa-420_

b-12-045_guidance_transport_conformity_2008_

oxone_naaqs.pdf. 

119 40 CFR 93.102(b)(2)(i). 

120 40 CFR 93.118(e)(4)(iii), (iv) and (v). For more 

information on the transportation conformity 

requirements and applicable policies on budgets, 

please visit our transportation conformity website 

at: http://www.epa.gov/otaq/stateresources/ 

transconf/index.htm. 

121 40 CFR 93.118(f)(2). 

122This is addressed in more detail in our 

memorandum for the budgets, as detailed in Section 

III.G.3. 

123Under the transportation conformity 

regulations, the EPA may review the adequacy of 

submitted motor vehicle emission budgets 

simultaneously with the EPA’s approval or 

disapproval of the submitted implementation plan. 

40 CFR 93.118(f)(2). 

contingency measure (i.e., a revised 

District rule or rules with contingent 

provisions). Conditional approvals are 

authorized under CAA section 110(k)(4). 

G. Motor Vehicle Emissions Budgets for 

Transportation Conformity 

1. Statutory and Regulatory 

Requirements 

Section 176(c) of the CAA requires 

federal actions in nonattainment and 

maintenance areas to conform to the 

SIP’s goals of eliminating or reducing 

the severity and number of violations of 

the NAAQS and achieving expeditious 

attainment of the standards. Conformity 

to the SIP’s goals means that such 

actions will not: (1) Cause or contribute 

to violations of a NAAQS, (2) worsen 

the severity of an existing violation, or 

(3) delay timely attainment of any 

NAAQS or any interim milestone. 

Actions involving Federal Highway 

Administration (FHWA) or Federal 

Transit Administration (FTA) funding 

or approval are subject to the EPA’s 

transportation conformity rule, codified 

at 40 CFR part 93, subpart A. Under this 

rule, metropolitan planning 

organizations in nonattainment and 

maintenance areas coordinate with state 

and local air quality and transportation 

agencies, the EPA, the FHWA, and the 

FTA to demonstrate that an area’s 

regional transportation plans and 

transportation improvement programs 

conform to the applicable SIP.118 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. Budgets are generally 

established for specific years and 

specific pollutants or precursors. Ozone 

plans should identify budgets for onroad emissions of ozone precursors 

(NOX and VOC) in the area for each RFP 

milestone year and, if the plan 

demonstrates attainment, the attainment 

year.119

For budgets to be approvable, they 

must meet, at a minimum, the EPA’s 

adequacy criteria (40 CFR 93.118(e)(4)) 

and be approvable under all pertinent 

SIP requirements. To meet these 

requirements, the budgets must be 

consistent with the attainment and RFP 

requirements and reflect all of the motor 

vehicle control measures contained in 

the attainment and RFP 

demonstrations.120

The EPA’s process for determining 

adequacy of a budget consists of three 

basic steps: (1) Providing public 

notification of a SIP submission; (2) 

providing the public the opportunity to 

comment on the budget during a public 

comment period; and (3) making a 

finding of adequacy or inadequacy.121

2. Summary of the State’s Submission 

Chapter VI of the 2018 Western 

Nevada County Ozone Plan includes 

budgets for the 2020 RFP milestone and 

attainment year. The budgets were 

derived from the 2011 base year. The 

budgets were calculated using 

EMFAC2014, CARB’s then-current and 

latest approved version of the EMFAC 

model for estimating emissions from onroad vehicles operating in California 

and are rounded up to the nearest whole 

number. The budgets in the Plan reflect 

updated VMT estimates from the NCTC 

2015–2035 Regional Transportation 

Plan, adopted by NCTC in January 2018, 

which are lower than the conservative 

estimate of on-road emissions in the 

emissions inventory. Given the use of 

updated travel data and CARB’s 

convention of rounding emissions up to 

the next tenth (0.1), there are some 

differences between the budgets and the 

emissions inventories in the Plan for the 

RFP and attainment demonstrations. 

CARB’s addendum to the technical 

clarification memorandum dated 

October 27, 2020 indicates that the 

differences are quite small (VOC: 0.55 

tpd; NOX: 0.26 tpd) and do not impact 

the RFP or attainment 

demonstrations.122 The conformity 

budgets for NOX and VOC in the Plan 

for the Western Nevada County area are 

provided in Table 5 below. 

TABLE 5—TRANSPORTATION CONFORMITY BUDGETS FOR 2020 FOR THE 2008 OZONE NAAQS IN WESTERN NEVADA

COUNTY

[Summer planning inventory, tpd] 

2020 

VOC NOX

Motor vehicle emissions budget .............................................................................................................................. 0.8 1.7 

Source: Table 7 of the 2018 Western Nevada County Ozone Plan. 

3. The EPA’s Review of the State’s 

Submission 

As part of our review of the 

approvability of the budgets in the 2018 

Western Nevada County Ozone Plan, we 

have evaluated the budgets using our 

adequacy criteria in 40 CFR 93.118(e)(4) 

and (5). We will complete the adequacy 

review concurrent with our final action 

on the 2018 Western Nevada County 

Ozone Plan. The transportation 

conformity rule does not require the 

EPA to find budgets adequate prior to 

proposing approval of them.123 Today, 

the EPA is announcing the beginning of 

the adequacy process for these budgets, 

and the public has 30 days to comment 

on their adequacy, per the 

transportation conformity regulation at 

40 CFR 93.118(f)(2)(i) and (ii). 

As documented in a separate 

memorandum included in the docket for 


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124Memorandum dated December 4, 2020, from 

Khoi Nguyen, Air Planning Office, EPA Region 9, 

to the docket for this proposed rulemaking, titled 

‘‘Adequacy Documentation for Plan Motor Vehicle 

Emission Budgets in 2018 Western Nevada County 

Ozone Plan.’’ 

125 40 CFR 93.118(e)(1). 

126CARB’s request to limit the duration of the 

approval of the Western Nevada County ozone 

budgets is contained in a letter dated December 2, 

2018, from Richard Corey, Executive Officer, CARB, 

to Mike Stoker, Regional Administrator, EPA 

Region IX. 

127See email dated August 17, 2020 from 

Nesamani Kalandiyur, CARB, to EPA Region 9. 

128 2008 Ozone SRR, 80 FR 12264, 12283 (March 

6, 2015). 

129 2018 Western Nevada County Ozone Plan, 

page 50. 

130 80 FR 12264 (March 6, 2015). 

131 2018 Western Nevada County Ozone Plan, 40. 

132 85 FR 74263 (November 20, 2020). 

133 64 FR 46849 (August 27, 1999). 

this rulemaking, we preliminarily 

conclude that the budgets in the 2018 

Western Nevada County Ozone Plan 

meet each adequacy criterion.124 While 

adequacy and approval are two separate 

actions, reviewing the budgets in terms 

of the adequacy criteria informs the 

EPA’s decision to propose to approve 

the budgets. We have completed our 

detailed review of the 2018 Western 

Nevada County Ozone Plan and are 

proposing herein to approve the SIP’s 

attainment and RFP demonstrations. We 

have also reviewed the budgets in the 

2018 Western Nevada County Ozone 

Plan and found that they are consistent 

with the attainment and RFP 

demonstrations for which we are 

proposing approval, are based on 

control measures that have already been 

adopted and implemented, and meet all 

other applicable statutory and 

regulatory requirements including the 

adequacy criteria in 40 CFR 

93.1118(e)(4) and (5). Therefore, we are 

proposing to find adequate and approve 

the 2020 budgets in the 2018 Western 

Nevada County Ozone Plan (and shown 

in Table 5, above). If we finalize our 

adequacy determination and approval of 

the budgets for the 2008 ozone NAAQS 

in the Plan as proposed, then they will 

be approved for use in transportation 

conformity determinations. 

Under our transportation conformity 

rule, as a general matter, once budgets 

are approved, they cannot be 

superseded by revised budgets 

submitted for the same CAA purpose 

and the same period of years addressed 

by the previously approved SIP until the 

EPA approves the revised budgets as a 

SIP revision. In other words, as a 

general matter, such approved budgets 

cannot be superseded by revised 

budgets found adequate, but rather only 

through approval of the revised budgets, 

unless the EPA specifies otherwise in its 

approval of a SIP by limiting the 

duration of the approval to last only 

until subsequently submitted budgets 

are found adequate.125

In this instance, CARB originally 

requested that we limit the duration of 

our approval of the budgets in the 2018 

Western Nevada County Ozone Plan 

only until the effective date of the EPA’s 

adequacy finding for any subsequently 

submitted budgets.126 However, in an 

email dated August 17, 2020, CARB 

indicated its decision to no longer 

request limited approval of the budgets 

for Western Nevada.127

H. Other Clean Air Act Requirements 

Applicable to Serious Ozone 

Nonattainment Areas 

In addition to the SIP requirements 

discussed in the previous sections, the 

CAA includes certain other SIP 

requirements applicable to Serious 

ozone nonattainment areas, such as 

Western Nevada County. We describe 

these provisions and their current status 

below for informational purposes only. 

1. Enhanced Vehicle Inspection and 

Maintenance Programs 

Section 182(c)(3) of the CAA requires 

states with ozone nonattainment areas 

classified under subpart 2 as Serious or 

above to implement an enhanced motor 

vehicle I/M program in each urbanized 

area within the nonattainment area, as 

defined by the Bureau of the Census, 

with a 1980 population of 200,000 or 

more. The requirements for those 

programs are provided in CAA section 

182(c)(3) and 40 CFR part 51, subpart S. 

Consistent with the 2008 Ozone SRR, 

no new I/M programs are currently 

required for nonattainment areas for the 

2008 ozone NAAQS.128 Further, because 

there are no urbanized areas in Nevada 

County, the Western Nevada County 

nonattainment area is not required to 

implement an enhanced I/M program. 

Nevada County has had a basic smog 

check program in place since 1998.129

2. New Source Review Rules 

Section 182(a)(2)(C) of the CAA 

requires states to develop SIP revisions 

containing permit programs for each of 

its ozone nonattainment areas. The SIP 

revisions are to include requirements for 

permits in accordance with CAA 

sections 172(c)(5) and 173 for the 

construction and operation of each new 

or modified major stationary source for 

VOC and NOX anywhere in the 

nonattainment area. The 2008 Ozone 

SRR includes provisions and guidance 

for nonattainment NSR programs.130

The 2018 Western Nevada County 

Ozone Plan cites District Rule 428, 

‘‘New Source Review Requirements for 

New and Modified Major Sources in 

Federally Designated Non-attainment 

Areas,’’ as amended by the District on 

June 27, 2016, as the rule that meets 

Serious area requirements for 

nonattainment NSR.131 Since the Plan’s 

submittal, the District rescinded the 

previously adopted Rule 428 and 

concurrently adopted a new Rule 428, 

‘‘NSR Requirements for New and 

Modified Major Sources in 

Nonattainment Areas,’’ on November 

25, 2019. The rule was submitted to the 

EPA on February 19, 2020. We approved 

this version of Rule 428 into the SIP on 

November 20, 2020.132

3. Clean Fuels Fleet Program 

Sections 182(c)(4)(A) and 246 of the 

CAA require California to submit to the 

EPA for approval into the SIP measures 

to implement a Clean Fuels Fleet 

Program. Section 182(c)(4)(B) of the 

CAA allows states to opt out of the 

federal clean-fuel vehicle fleet program 

by submitting a SIP revision consisting 

of a program or programs that will result 

in at least equivalent long-term 

reductions in ozone precursors and 

toxic air emissions. 

In 1994, CARB submitted a SIP 

revision to the EPA to opt out of the 

federal clean-fuel fleet program. The 

submittal included a demonstration that 

California’s low-emissions vehicle 

program achieved emissions reductions 

at least as large as would be achieved by 

the federal program. The EPA approved 

the SIP revision to opt out of the federal 

program on August 27, 1999.133 There 

have been no changes to the federal 

Clean Fuels Fleet program since the 

EPA approved the California SIP 

revision to opt out of the federal 

program, and thus, no corresponding 

changes to the SIP are required. Thus, 

we find that the California SIP revision 

to opt out of the federal program, as 

approved in 1999, meets the 

requirements of CAA sections 

182(c)(4)(A) and 246 for Western 

Nevada County for the 2008 ozone 

NAAQS. 

4. Gasoline Vapor Recovery 

Section 182(b)(3) of the CAA requires 

states to submit a SIP revision by 

November 15, 1992, that requires 

owners or operators of gasoline 

dispensing systems to install and 

operate gasoline vehicle refueling vapor 

recovery (‘‘Stage II’’) systems in ozone 

nonattainment areas classified as 

Moderate and above. California’s ozone 

nonattainment areas implemented Stage 


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134 General Preamble, 57 FR 13498 at 13514 

(April 16, 1992). 

135 77 FR 28772, at 28774 (May 16, 2012). 

136See 40 CFR 51.126(b). 

137 76 FR 44493 (July 26, 2011). 

138 58 FR 8452 (February 12, 1993). 

139 71 FR 61236 (October 17, 2006). 

140 40 CFR 58.2(b) now provides ‘‘The 

requirements pertaining to provisions for an air 

quality surveillance system in the SIP are contained 

in this part.’’ 

141The 2008 ozone SRR addresses PAMS-related 

requirements at 80 FR 12264, at 12291 (March 6, 

2015). 

142Letter dated November 5, 2020, from Gwen 

Yoshimura, Manager, Air Quality Analysis Office, 

EPA Region IX, to Ravi Ramalingam, Chief, 

Consumer Products and Air Quality Assessment 

Branch, Air Quality Planning and Science Division, 

CARB. 

143Letter dated November 9, 2020, from Dr. 

Michael T. Benjamin, Chief, Air Quality Planning 

and Science Division, CARB, to Meredith Kurpius, 

Assistant Director, EPA Region 9, enclosing the 

‘‘2020 Monitoring Network Assessment (October 

2020).’’ The assessment includes a five-year 

network assessment and an updated enhanced 

monitoring plan, as required by 40 CFR 58, 

Appendix D, Section 5(a). 

II vapor recovery well before the passage 

of the CAA Amendments of 1990.134

Section 202(a)(6) of the CAA requires 

the EPA to promulgate standards 

requiring motor vehicles to be equipped 

with onboard refueling vapor recovery 

(ORVR) systems. The EPA promulgated 

the first set of ORVR system regulations 

in 1994 for phased implementation on 

vehicle manufacturers, and since the 

end of 2006, essentially all new 

gasoline-powered light and mediumduty vehicles are ORVR-equipped.135

Section 202(a)(6) also authorizes the 

EPA to waive the SIP requirement under 

CAA section 182(b)(3) for installation of 

Stage II vapor recovery systems after 

such time as the EPA determines that 

ORVR systems are in widespread use 

throughout the motor vehicle fleet. 

Effective May 16, 2012, the EPA waived 

the requirement of CAA section 

182(b)(3) for Stage II vapor recovery 

systems in ozone nonattainment areas 

regardless of classification.136 Thus, a 

SIP submittal meeting CAA section 

182(b)(3) is not required for the 2008 

ozone NAAQS. 

While a SIP submittal meeting CAA 

section 182(b)(3) is not required for the 

2008 ozone NAAQS, under California 

State law (i.e., Health and Safety Code 

section 41954), CARB is required to 

adopt procedures and performance 

standards for controlling gasoline 

emissions from gasoline marketing 

operations, including transfer and 

storage operations. State law also 

authorizes CARB, in cooperation with 

local air districts, to certify vapor 

recovery systems, to identify defective 

equipment and to develop test methods. 

CARB has adopted numerous revisions 

to its vapor recovery program 

regulations and continues to rely on its 

vapor recovery program to achieve 

emissions reductions in ozone 

nonattainment areas in California. 

In Western Nevada County, the 

installation and operation of CARBcertified vapor recovery equipment is 

required and enforced through 

NSAQMD Rule 215, ‘‘Phase II Vapor 

Recovery System Requirements,’’ which 

was most recently approved into the SIP 

on July 26, 2011.137

5. Enhanced Ambient Air Monitoring 

Section 182(c)(1) of the CAA requires 

that all ozone nonattainment areas 

classified as Serious or above 

implement measures to enhance and 

improve monitoring for ambient 

concentrations of ozone, NOX, and VOC, 

and to improve monitoring of emissions 

of NOX and VOC. The enhanced 

monitoring network for ozone is referred 

to as the Photochemical Assessment 

Monitoring Station (PAMS) network. 

The EPA promulgated final PAMS 

regulations on February 12, 1993.138

Prior to 2006, the EPA’s ambient air 

monitoring regulations in 40 CFR part 

58, ‘‘Ambient Air Quality Surveillance,’’ 

set forth specific SIP requirements (see 

former 40 CFR 52.20). In 2006, the EPA 

significantly revised and reorganized 40 

CFR part 58.139 Under revised 40 CFR 

part 58, SIP revisions are no longer 

required; rather, compliance with EPA 

monitoring regulations is established 

through review of required annual 

monitoring network plans.140 The 2008 

Ozone SRR made no changes to these 

requirements.141

The 2018 Western Nevada County 

Ozone Plan does not specifically 

address the enhanced ambient air 

monitoring requirement in CAA section 

182(c)(1). However, we note that CARB 

includes the ambient monitoring 

network within Western Nevada 

County, in its annual monitoring 

network plan that is submitted to the 

EPA, and that we have approved the 

most recent annual monitoring network 

plan (‘‘Annual Network Plan Covering 

Monitoring Operations in 25 California 

Air Districts, July 2020’’ or ‘‘2020 ANP’’) 

with respect to Western Nevada 

County.142 In addition, CARB has 

fulfilled the requirement under 40 CFR 

part 58, Appendix D, section 5(h), to 

submit an enhanced monitoring plan for 

Western Nevada County.143 Based on 

our review and approval of the 2020 

ANP with respect to Western Nevada 

County and CARB’s submittal of an 

enhanced monitoring plan for Western 

Nevada County, we propose to find that 

CARB and the NSAQMD meet the 

enhanced monitoring requirements 

under CAA section 182(c)(1) for 

Western Nevada County with respect to 

the 2008 ozone NAAQS. 

IV. Proposed Action 

For the reasons discussed in this 

notice, under CAA section 110(k)(3), the 

EPA is proposing to approve as a 

revision to the California SIP the 

following portions of the 2018 Western 

Nevada County Ozone Plan submitted 

by CARB on December 2, 2018: 

• Base year emissions inventory 

element as meeting the requirements of 

CAA sections 172(c)(3) and 182(a)(1) 

and 40 CFR 51.1115 for the 2008 ozone 

NAAQS; 

• RACM demonstration element as 

meeting the requirements of CAA 

section 172(c)(1) and 40 CFR 51.1112(c) 

for the 2008 ozone NAAQS; 

• Attainment demonstration element 

for the 2008 ozone NAAQS as meeting 

the requirements of CAA section 

182(c)(2)(A) and 40 CFR 51.1108; 

• ROP demonstration element as 

meeting the requirements of CAA 

182(b)(1) and 40 CFR 51.1110(a)(4)(i) for 

the 2008 ozone NAAQS; 

• RFP demonstration element as 

meeting the requirements of CAA 

sections 172(c)(2), 182(b)(1), and 

182(c)(2)(B), and 40 CFR 

51.1110(a)(4)(iii) for the 2008 ozone 

NAAQS; 

• Motor vehicle emissions budgets for 

the RFP milestone and attainment year 

of 2020 (see Table 5) because they are 

consistent with the RFP and attainment 

demonstrations for the 2008 ozone 

NAAQS proposed for approval herein 

and meet the other criteria in 40 CFR 

93.118(e); 

We are also proposing to find that the: 

• California SIP revision to opt-out of 

the federal Clean Fuels Fleet Program 

meets the requirements of CAA sections 

182(c)(4)(A) and 246 and 40 CFR 

51.1102 for the 2008 ozone NAAQS 

with respect to Western Nevada County; 

and 

• Requirements for enhanced 

monitoring under CAA section 182(c)(1) 

and 40 CFR 51.1102 for Western Nevada 

County for the 2008 ozone NAAQS have 

been met. 

In addition, we are proposing, under 

CAA section 110(k)(4), to approve 

conditionally the contingency measures 

element of the 2018 Western Nevada 

County Ozone Plan as meeting the 

requirements of CAA sections 172(c)(9) 

and 182(c)(9) for RFP and attainment 

contingency measures. Our proposed 

approval is based on commitments by 

the District and CARB to supplement 

the element through submission, as a 

SIP revision (within one year of our 


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final conditional approval action), of a 

new District rule that would add new 

limits or other requirements if an RFP 

milestone is not met or if Western 

Nevada County fails to attain the 2008 

ozone NAAQS by the applicable 

attainment date. 

V. Statutory and Executive Order 

Reviews 

Under the Clean Air Act, the 

Administrator is required to approve a 

SIP submission that complies with the 

provisions of the Act and applicable 

federal regulations. 42 U.S.C. 7410(k); 

40 CFR 52.02(a). Thus, in reviewing SIP 

submissions, the EPA’s role is to 

approve state choices, provided that 

they meet the criteria of the Clean Air 

Act. Accordingly, this proposed action 

merely proposes to approve, or 

conditionally approve, state plans as 

meeting federal requirements and does 

not impose additional requirements 

beyond those imposed by state law. For 

that reason, this proposed action: 

• Is not a ‘‘significant regulatory 

action’’ subject to review by the Office 

of Management and Budget under 

Executive Orders 12866 (58 FR 51735, 

October 4, 1993) and 13563 (76 FR 3821, 

January 21, 2011); 

• Is not an Executive Order 13771 (82 

FR 9339, February 2, 2017) regulatory 

action because SIP approvals are 

exempted under Executive Order 12866; 

• Does not impose an information 

collection burden under the provisions 

of the Paperwork Reduction Act (44 

U.S.C. 3501 et seq.); 

• Is certified as not having a 

significant economic impact on a 

substantial number of small entities 

under the Regulatory Flexibility Act (5 

U.S.C. 601 et seq.); 

• Does not contain any unfunded 

mandate or significantly or uniquely 

affect small governments, as described 

in the Unfunded Mandates Reform Act 

of 1995 (Pub. L. 104–4); 

• Does not have federalism 

implications as specified in Executive 

Order 13132 (64 FR 43255, August 10, 

1999); 

• Is not an economically significant 

regulatory action based on health or 

safety risks subject to Executive Order 

13045 (62 FR 19885, April 23, 1997); 

• Is not a significant regulatory action 

subject to Executive Order 13211 (66 FR 

28355, May 22, 2001); 

• Is not subject to requirements of 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act of 1995 (15 U.S.C. 272 note) because 

application of those requirements would 

be inconsistent with the Clean Air Act; 

and 

• Does not provide the EPA with the 

discretionary authority to address 

disproportionate human health or 

environmental effects with practical, 

appropriate, and legally permissible 

methods under Executive Order 12898 

(59 FR 7629, February 16, 1994). 

In addition, the SIP is not approved 

to apply on any Indian reservation land 

or in any other area where the EPA or 

an Indian tribe has demonstrated that a 

tribe has jurisdiction. In those areas of 

Indian country, the proposed rule does 

not have tribal implications and will not 

impose substantial direct costs on tribal 

governments or preempt tribal law as 

specified by Executive Order 13175 (65 

FR 67249, November 9, 2000). 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Incorporation by 

reference, Intergovernmental relations, 

Nitrogen dioxide, Ozone, Reporting and 

recordkeeping requirements, Volatile 

organic compounds. 

Authority: 42 U.S.C. 7401 et seq. 

Dated: December 21, 2020. 

John Busterud, 

Regional Administrator, Region IX. 

[FR Doc. 2020–28885 Filed 1–11–21; 8:45 am] 

BILLING CODE 6560–50–P 

FEDERAL COMMUNICATIONS 

COMMISSION 

47 CFR Parts 2 and 95 

[ET Docket No. 20–382; FCC 20–180; FRS 

17351] 

Allowing Earlier Equipment Marketing 

and Importation Opportunities 

AGENCY: Federal Communications 

Commission. 

ACTION: Proposed rule. 

SUMMARY: The Commission proposes to 

update its radiofrequency (RF) device 

marketing and importation rules in 

order to allow equipment manufacturers 

to better gauge consumer interest and 

prepare for new product launches. In 

particular, the Commission proposes 

limited exceptions to its requirement 

that RF devices receive equipment 

authorization prior to marketing in or 

importation to the United States and it 

seeks comment on the conditions 

necessary to ensure that parties who 

utilize such exceptions ultimately bring 

such devices into full compliance with 

the Commission’s equipment 

authorization rules. 

DATES: Comments are due February 11, 

2021. Reply comments are due February 

26, 2021. 

FOR FURTHER INFORMATION CONTACT: 

Brian Butler, Office of Engineering and 

Technology, 202–418–2702, 

Brian.Butler@fcc.gov, or Thomas Struble 

at 202–418–2470 or Thomas.Struble@

fcc.gov. 

SUPPLEMENTARY INFORMATION: This is a 

summary of the Commission’s Notice of 

Proposed Rulemaking (NPRM), FCC 20– 

180, ET Docket No. 20–382, adopted 

December 10, 2020, and released 

December 10, 2020. The full text of this 

document is available for public 

inspection and can be downloaded at: 

https://www.fcc.gov/document/fccproposes-rules-expedite-release-newdevices-and-technologies-0 or by using 

the search function for ET Docket No. 

20–382 on the Commission’s ECFS web 

page at www.fcc.gov/ecfs. 

Synopsis 

1. Discussion. In June 2020 CTA filed 

a petition seeking modification of the 

equipment authorization rules 

pertaining to the marketing and 

importation of radiofrequency devices. 

An FCC-issued Public Notice seeking 

comment on CTA’s petition yielded 

eight comments and two reply 

comments. The Commission took this 

record into consideration when it issued 

this rulemaking proposal. The 

Commission observed that the existing 

rules often limit the ability of device 

manufacturers to market and import 

radiofrequency devices in the most 

efficient and cost-effective manner and 

proposed specific rule changes that 

would allow device manufacturers to 

take full advantage of modern marketing 

and importation practices. Specifically, 

the proposals relate to the marketing 

and importation of radiofrequency 

devices. Although CTA also asked the 

Commission to grant a rule waiver to 

permit conditional sales to consumers 

during the pendency of the rulemaking 

proceeding and other parties asked for 

similar action, the Commission 

determined that an interim waiver was 

not warranted in this case. The 

Commission notes that it would need to 

consider several complex issues before 

allowing conditional sales of 

radiofrequency devices, or additional 

imports of radiofrequency devices, prior 

to the receipt of equipment 

authorization. 

2. The Commission’s equipment 

authorization rules are based on Section 

302 of the Communications Act of 1934, 

as amended (the Act), 47 U.S.C. 302a, 

which gives the Commission authority 

to make reasonable regulations 

governing the interference potential of 

devices that emit radiofrequency energy 

and can cause harm to consumers or 


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