Federal Register / Vol. 90, No. 12 / Tuesday, January 21, 2025 / Rules and Regulations 6823 

1 89 FR 26817. 

2SCAQMD, ‘‘Final Coachella Valley Extreme 

Area Plan for the 1997 8-Hour Ozone Standard,’’ 

December 2020. 

3Letter dated December 28, 2020, from Richard 

W. Corey, Executive Officer, CARB, to John W. 

Busterud, Regional Administrator, EPA Region 9 

(submitted electronically December 29, 2020). 

4CARB, Staff Report, ‘‘2020 Coachella Valley 

Vehicle Miles Traveled Emissions Offset 

Demonstration,’’ release date January 22, 2021. 

5Letter dated March 15, 2021, from Richard W. 

Corey, Executive Officer, CARB, to Deborah Jordan, 

Acting Regional Administrator, EPA Region 9 

(submitted electronically March 18, 2021). 

6 89 FR 49815. 

7 89 FR 26817, 26826. 

8See Coachella Valley Ozone Plan, pp. 4–4 

through 4–17. 

EPA-APPROVED OHIO REGULATIONS—Continued 

Ohio 

citation Title/subject Ohio effective date EPA approval date Notes 

*******

* * * * * 

[FR Doc. 2025–00968 Filed 1–17–25; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R09–OAR–2023–0448; FRL–11677– 

03–R9] 

Approval and Promulgation of 

Implementation Plans; State of 

California; Coachella Valley; Extreme 

Attainment Plan for 1997 8-Hour Ozone 

Standards 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Final rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is taking final action to 

approve elements of a state 

implementation plan (SIP) submittal 

from the State of California to meet 

Clean Air Act (CAA) ‘‘Extreme’’ 

nonattainment area requirements for the 

1997 8-hour ozone national ambient air 

quality standards (NAAQS) in the 

Riverside Co. (Coachella Valley), CA 

nonattainment area (‘‘Coachella 

Valley’’). We are specifically approving 

the reasonable further progress (RFP) 

demonstration and the vehicle miles 

traveled demonstration. 

DATES: This rule is effective February 

20, 2025. 

ADDRESSES: The EPA has established a 

docket for this action under Docket ID 

No. EPA–R09–OAR–2023–0448. All 

documents in the docket are listed on 

the https://www.regulations.gov 

website. Although listed in the index, 

some information is not publicly 

available, e.g., Confidential Business 

Information (CBI) or other information 

whose disclosure is restricted by statute. 

Certain other material, such as 

copyrighted material, is not placed on 

the internet and will be publicly 

available only in hard copy form. 

Publicly available docket materials are 

available through https://

www.regulations.gov, or please contact 

the person identified in the FOR FURTHER

INFORMATION CONTACT section for 

additional availability information. If 

you need assistance in a language other 

than English or if you are a person with 

a disability 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: Tom 

Kelly, Geographic Strategies and 

Modeling Section (AIR–2–2), EPA 

Region IX, 75 Hawthorne Street, San 

Francisco, CA 94105; phone: (415) 972– 

3856; or email: kelly.thomasp@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Throughout this document, ‘‘we,’’ ‘‘us,’’ 

and ‘‘our’’ refer to the EPA. 

Table of Contents 

I. Proposed Action 

II. Public Comments and the EPA’s 

Responses 

III. The EPA’s Action 

IV. Statutory and Executive Order Reviews 

I. Proposed Action 

A. Summary 

On April 16, 2024,1 the EPA proposed 

to approve two SIP submittals from the 

South Coast Air Quality Management 

District (SCAQMD or ‘‘District’’) and the 

California Air Resources Board (CARB) 

addressing the Extreme area planning 

requirements for the 1997 ozone 

NAAQS in Coachella Valley. The first 

submittal, the ‘‘Final Coachella Valley 

Extreme Area Plan for the 1997 8-Hour 

Ozone Standard’’ (‘‘Coachella Valley 

Ozone Plan’’ or ‘‘Plan’’),2 was prepared 

by the SCAQMD and submitted by 

CARB on December 29, 2020.3 We 

proposed to approve all elements of the 

Plan except the reasonably available 

control technology (RACT) 

demonstration, which we plan to 

address in a subsequent rulemaking. 

The second submittal, the ‘‘2020 

Coachella Valley Vehicle Miles Traveled 

Emissions Offset Demonstration’’ 

(‘‘VMT Offset Demonstration’’),4 was 

prepared by CARB and submitted on 

March 18, 2021.5 We proposed to 

approve the entire VMT Offset 

Demonstration. Our proposed action 

contains more information on the two 

submittals and our evaluation. 

On June 12, 2024, we finalized our 

proposed action on certain portions of 

the Coachella Valley Ozone Plan.6

Specifically, we finalized approval of 

the reasonably available control 

measures demonstration, the attainment 

demonstration, and the State’s 

demonstration that it has satisfied the 

clean fuels for boilers requirement for 

the Coachella Valley nonattainment 

area. Our June 12, 2024, notice stated 

that we intended to take final action on 

the remaining VMT Offset 

Demonstration and RFP demonstration 

in a future rulemaking. We are finalizing 

approval of these elements in this 

notice. 

B. Correction 

In summarizing the State’s 

photochemical modeling and the 

associated control measures, the EPA’s 

proposed rule incorrectly stated that the 

Coachella Valley control strategy for the 

1997 ozone NAAQS relies on aggregate 

emissions reduction commitments from 

the ‘‘Final 2016 Air Quality 

Management Plan’’ (‘‘2016 AQMP’’).7

While the Coachella Valley Ozone Plan 

discusses rules addressing the area’s 

progress related to commitments needed 

for the area to meet the 2008 ozone 

NAAQS by 2026, the emissions 

reductions associated with these rules 

are not reflected in the area’s inventory, 

and the Plan does not rely on the 

commitments to attain the 1997 ozone 

NAAQS in 2023.8

II. Public Comments and the EPA’s 

Responses 

The EPA’s proposed action provided 

a 30-day public comment period. During 

this period, we received comments from 

Air Law for All (ALFA), dated May 16, 

2024. These comments relate to our 

proposed action on the RFP 

demonstration. No comments were 

received on other parts of the proposal. 

The comments are summarized and 

addressed below. 


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9For example, in addition to the contingency 

measures submittal noted previously, the EPA 

recently received the State’s submittal to address 

the fee requirements of CAA section 185 for the 

Coachella Valley. Letter from Steven S. Cliff, CARB, 

to Martha Guzman, EPA, dated August 9, 2024, and 

submitted electronically on August 13, 2024. 

10See, e.g., 85 FR 8181 (February 13, 2020), 85 

FR 11817 (February 27, 2020) (acting separately on 

Imperial Valley RACT element and ozone plan, 

respectively, for the 2008 ozone NAAQS). 

11Contingency measures were submitted on 

November 28, 2007, in the SCAQMD ‘‘Final 2007 

Air Quality Management Plan,’’ transmitted to the 

EPA in a letter from James N. Goldstene, CARB, to 

Wayne Nastri, EPA, and withdrawn by the District, 

in a letter dated April 7, 2020, from Wayne Nastri, 

SCAQMD to Richard Corey, CARB, and withdrawn 

by CARB in a letter dated April 28, 2020, from 

Richard Corey, CARB, to John W. Busterud, EPA. 

12See esp. Bahr v. EPA, 836 F.3d 1218 (9th Cir. 

2016); Sierra Club v. EPA, 21 F.4th 815 (D.C. Cir. 

2021); Association of Irritated Residents v. EPA, 10 

F.4th 937 (9th Cir. 2021). 

13 88 FR 17571 (March 23, 2023). 

Comment #1: ALFA criticizes the 

EPA’s proposal to decline to act on the 

area’s contingency measures and new 

source review (NSR) submittals for the 

1997 ozone NAAQS. The commenter 

argues that the EPA lacks discretion to 

act on selected portions of submittals 

when the 18-month statutory deadline 

for action has passed. The commenter 

states that CAA section 110(k) does not 

explicitly grant the EPA authority to act 

on selected portions of submittals, and 

argues that when an agency exercises 

discretion, it must give permissible 

reasons for doing so. The commenter 

asserts that the EPA has not given a 

permissible reason for acting on only 

portions of the submittal and speculates 

that the EPA has done so only to delay 

disapproval of the provisions and avoid 

starting the associated sanctions and 

federal implementation plan clocks. The 

commenter also points out that the EPA 

noted in the proposal that the State has 

not yet submitted certain required 

portions of the plan, and states that EPA 

has not offered an explanation for not 

making a finding of failure to submit for 

those missing portions of the attainment 

plan. 

Response to Comment #1: As a 

general matter, comments regarding SIP 

elements not addressed in the proposed 

rule are outside the scope of this action. 

The EPA intends to address all required 

planning elements for the Coachella 

Valley for the 1997 ozone NAAQS in 

subsequent actions.9

While the EPA has a statutory 

deadline by which to act on all SIP 

submittals under CAA section 110(k)(2), 

the EPA is not obligated to act on all SIP 

submittals or all SIP elements for a 

nonattainment area in the same action. 

The EPA routinely takes separate 

actions on submittals or portions of 

submittals that address unique CAA 

requirements.10 The EPA strives to meet 

all statutory deadlines; however, the 

EPA acknowledges that we are 

sometimes delayed due to resource 

limitations and other practical 

constraints. 

With respect to the Coachella Valley 

contingency measures, the EPA notes 

that CARB and the SCAQMD previously 

made a submittal addressing the 

contingency measures requirement for 

the 1997 ozone NAAQS that was 

subsequently withdrawn,11 and the EPA 

has no obligation to act on withdrawn 

submittals. The EPA’s current approach 

for evaluating contingency measures 

submittals has been shaped by several 

recent court decisions.12 In response to 

these decisions, the EPA has issued the 

draft guidance cited in our proposed 

action, titled ‘‘DRAFT: Guidance on the 

Preparation of State Implementation 

Plan Provisions that Address the 

Nonattainment Area Contingency 

Measure Requirements for Ozone and 

Particulate Matter.’’ 13 Following our 

issuance of this draft guidance 

document, the District and CARB 

submitted Coachella Valley contingency 

measures for the 1997 ozone NAAQS to 

the EPA on April 3, 2024. The EPA 

notes that the statutory deadline to act 

on that submittal under CAA section 

110(k)(2) has not yet passed. 

Comment #2: ALFA comments that 

the submittal fails to show that the 

substitute NOX emissions reductions 

will ‘‘result in a reduction of ozone 

concentrations at least equivalent’’ to 

the required 3 percent per annum VOC 

emissions reductions, and that as a 

result, the EPA’s proposed approval is 

arbitrary and capricious and contrary to 

law. The commenter describes the 

relative roles of VOC and NOX in ozone 

formation, including the existence of an 

‘‘optimum’’ VOC to NOX ratio for a 

given level of VOC (i.e., a NOX

concentration at which the maximum 

amount of ozone is produced). As 

explained by the commenter, in a ‘‘NOX

saturated’’ situation where NOX levels 

exceed this optimum ratio, a reduction 

in NOX levels can lead to increases in 

ozone levels, and in a ‘‘NOX limited’’ 

situation with NOX levels below the 

optimum ratio, VOC reductions toward 

the optimum ratio may have little effect 

on ozone levels. As a result, the 

commenter says, ozone response to 

precursor control can vary greatly 

between areas. The commenter argues 

that language in the CAA, including 

CAA sections 185B, 182(f), and 

182(c)(2)(C), indicates that Congress was 

aware of these issues, including that in 

some scenarios NOX reductions may not 

decrease ozone concentrations. 

The commenter also points to the 

EPA’s consideration of the relative 

effectiveness of NOX and VOC controls 

for interpollutant offset trading under 

the new source review (NSR) permitting 

program and in applying requirements 

for major stationary sources of VOC to 

NOX sources under CAA 182(f), noting 

that in these situations EPA guidance 

indicates that photochemical grid 

modeling of multiple scenarios should 

be conducted to support demonstrations 

related to the relative effectiveness of 

controls. Through these comparisons, 

the commenter suggests that the 

Coachella Valley submittal should have 

included similar photochemical grid 

modeling to determine whether the 

substitute NOX emissions reductions 

result in equivalent ozone reductions. 

While acknowledging that ozone 

isopleths, which are graphs of ozone 

levels resulting from various levels of 

emissions reductions for each 

monitoring station, are a technically 

sound method of comparing the relative 

benefits of reducing NOX and VOC 

emissions, the commenter states that the 

EPA’s overall analysis is insufficient 

and that there are missing steps in going 

from isopleths to a justification for the 

percentage method in the NOX

Substitution Guidance. The commenter 

states, ‘‘if EPA plans to rely on the 

isopleths’’ as the justification for NOX

substitution, ‘‘EPA must re-propose its 

action with an explanation that is 

reasonably detailed enough for the 

public to be able to comment on it.’’ The 

commenter further states that CAA 

section 182(c)(2)(C)’s use of the plural 

‘‘ozone concentrations’’ means that an 

equivalency demonstration at a single 

monitoring site would be contrary to the 

CAA and argues that Congress intended 

the equivalence requirement to apply 

throughout the nonattainment area. 

Response to Comment #2: We 

disagree with the commenter’s 

characterization of the District’s 

submittal and the EPA’s proposed 

approval. As described further in this 

document, the EPA concludes that the 

analysis included with the modeling 

and control strategy in the Coachella 

Valley Ozone Plan adequately 

demonstrates that plan reductions of 

VOC and NOX would result in a 

reduction in ozone concentrations at 

least equivalent to that resulting from 

VOC emissions reductions. This 

condition is required under CAA 

182(c)(2)(C) for substituting NOX

reductions for VOC reductions. We 

therefore conclude that the District’s use 

of NOX substitution in the RFP 

demonstration for the Coachella Valley 

is appropriate in this circumstance. 


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14See file titled ‘‘D.1.a. Riverside NOX & VOC 

Emissions.xlsx’’ in the docket for this rulemaking, 

which displays information from the EPA’s 

Emissions Inventory Gateway (https://

www.epa.gov/air-emissions-inventories/emissionsinventory-system-eis-gateway). 

15 Id. 

16Wildfire emissions are a large source of NOX

emissions and are included the model evaluation 

but are not factored into the base and future year 

attainment modeling. Additionally, the influence of 

wildfire can be excluded from an EPA attainment 

finding as an exceptional event, in accordance with 

the EPA’s Exceptional Events Rule 81 FR 68216 

(October 3, 2016). 

17Coachella Valley Ozone Plan, p. 2–3, figure 2– 

3. 

18 2018 Coachella Valley Ozone Plan, p. 3–6, table 

3–3. 

19The VOC:NOX ratio increases due to chemical 

conversion to HNO3 and due to the process of 

deposition to surfaces, which removes NOX (in the 

form of HNO3) from the air more quickly than VOC. 

Barbara J. Finlayson-Pitts and James N. Pitts Jr., 

1993, ‘‘Atmospheric Chemistry of Tropospheric 

Ozone Formation: Scientific and Regulatory 

Implications,’’ Journal of the Air and Waste 

Management Association, 43:8, 1091–1100, https:// 

doi.org/10.1080/1073161X.1993.10467187. 

20The isopleths include biogenic VOCs in the 

analysis as constant values, showing changes only 

to anthropogenic emissions. 

21Coachella Valley Ozone Plan, p. 5–8, Figure 5– 

5. See also 89 FR 26817, 26826 (citing isopleth and 

surrounding discussion). 

22 2016 AQMP, appendix V, Attachment 5, page 

10. 

24 Id. 

One factor, not discussed in the 

Coachella Valley Ozone Plan, that 

contributes to the NOX-limited 

conditions is biogenic VOC emissions 

from vegetation. Biogenic VOC 

emissions are not required to be 

reported in nonattainment area 

inventories. Biogenic emissions are, 

however, included in the inventory 

used to model attainment in the Plan, 

and do contribute to the formation of 

ozone in the area. The most recent 

National Emissions Inventory estimates 

that biogenic VOC emissions represent 

more than 37 percent of VOC emissions 

in Riverside County.14 California’s 

statewide estimate for biogenic VOC 

emissions represents nearly 43 percent 

of the total VOC inventory. Biogenic 

NOX, in comparison, represent only 3.4 

percent of Riverside County NOX

emissions and 7.7 percent of statewide 

NOX.15 Because biogenic VOC is such a 

large portion of the inventory, reducing 

anthropogenic VOC emissions 

represents a smaller reduction in total 

VOC than a corresponding reduction of 

anthropogenic NOX compared to total 

NOX reductions.16 When biogenic 

emissions are taken into account, the 

amount of NOX relative to VOC is 

smaller, tending to make the ozone 

chemistry more NOX-limited. That is, 

reductions of NOX are even more 

effective than VOC reductions at 

reducing ozone, and appropriate to 

substitute for VOC reductions to achieve 

equivalent ozone concentration 

reductions. 

The Coachella Valley Ozone Plan 

provides ample documentation that the 

transport of ozone and ozone precursors 

in the South Coast Air Basin is the 

primary cause of high ozone 

concentrations in the Coachella Valley, 

such as the correlation between the 

annual number of exceedance days for 

the two areas.17 The Plan relies on 

upwind reductions within the South 

Coast Air Basin, where NOX and VOC 

emissions are respectively more than 20 

and nearly 27 times larger than those 

within Coachella Valley.18 By the time 

ozone precursors have been transported 

to the Coachella Valley, NOX has been 

preferentially removed by chemical and 

physical processes.19 At the same time, 

there are fewer NOX emissions and more 

biogenic VOC emissions in moving from 

the more developed Los Angeles urban 

area to the more rural Coachella area. 

This leaves less NOX available to form 

ozone, creating a NOX-limited condition 

where NOX emissions reductions are 

more effective than VOC emissions 

reductions at decreasing ozone 

concentrations. 

The isopleth diagrams in the 

Coachella Valley Ozone Plan show that 

NOX reductions are more effective than 

VOC reductions at decreasing ozone 

across a wide range of VOC emissions 

quantities, which is all that is needed to 

show that substitution on a 1–1 basis 

yields a reduction in ozone 

concentrations at least equivalent to the 

required VOC reductions.20 The District 

generated these diagrams by using 

photochemical grid modeling to 

simulate various combinations of NOX

and VOC emissions reductions and then 

plotting the resulting ozone 

concentrations for the monitor. Thus, 

while the commenter suggests that the 

submittal should have included 

photochemical modeling, that modeling 

is the basis of the analysis already 

provided in the form of the isopleth 

diagrams. The isopleth diagrams have 

VOC emissions on the horizontal x-axis 

and NOX emissions on the vertical yaxis. Isopleth lines represent the ozone 

concentration at different levels of VOC 

and NOX emissions, and a 45-degree 

line sloping from upper left to lower 

right would indicate that NOX and VOC 

emissions reductions are equally 

effective at reducing ozone 

concentrations. 

For the Palm Springs monitor, which 

is the only monitor in the Coachella 

Valley exceeding the 1997 ozone 

NAAQS, the diagram shows nearly 

horizontal isopleth lines.21 This 

indicates a very small ozone response to 

VOC reductions, so that ozone 

formation in the Palm Springs area is 

much more responsive to NOX

emissions reductions than to VOC 

reductions. The 2016 AQMP’s isopleth 

for Indio-Jackson Street monitor near 

the center of the nonattainment area 

shows a similarly flat slope.22

In other words, the graphs show that 

when NOX emissions are reduced, the 

level of ozone decreases substantially, 

and that, in contrast, reducing the level 

of VOC emissions results in much less 

reduction in the level of ozone. The 

curve of the line on the graphs indicates 

that reductions in NOX emissions will 

be considerably more effective than 

VOC reductions in reducing ozone 

concentrations on both a mass and 

percentage basis, and that VOC 

reductions will achieve only minor 

reductions in ozone concentrations even 

under scenarios involving large VOC 

reductions relative to current levels. 

Because NOX reductions are more 

effective than VOC reductions at 

reducing ozone concentrations, the 

Plan’s NOX to VOC substitution ratio of 

one to one (equivalent on a percentage 

basis) is a conservative way to 

determine the amount of NOX

reductions needed to replace VOC 

emissions reductions and result in at 

least an equivalent ozone decrease in 

ozone concentration as required under 

CAA section 182(c)(2). 

In fact, the isopleths show that a given 

percentage of NOX reductions provide 

more of a reduction in ozone 

concentration than the same percentage 

of VOC reductions.23 Thus, the Plan’s 

NOx to VOC substitution ratio of one to 

one is an appropriate ratio here and the 

analysis is not missing steps, as the 

commenter has alleged. As explained, 

the isopleths for the two Coachella 

Valley monitoring sites (Indio-Jackson 

Street and Palm Springs-Fire Station) 

show that ozone concentrations are 

more sensitive to reductions in NOX

than reductions in VOC across a wide 

range of VOC emissions quantities. In 

addition, the Plan provides multiple 

lines of evidence to support its 

statement that ‘‘ozone concentration in 

Palm Springs is much more sensitive to 

changes in NOX emissions than to 

changes in VOC emissions and indicates 

that NOX emission reduction is key for 

ozone attainment in the Coachella 

Valley.’’ 24 Thus, as the Coachella Valley 

Ozone Plan’s modeling and control 

strategy demonstrates, NOX reductions 

are more effective than VOC reductions 

in reducing ozone concentration for this 


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25E.g., CAA section 107(e)(2); CAA section 

110(a)(5)(D). 

26NOX Substitution Guidance, Office of Air 

Quality Planning and Standards, U.S. 

Environmental Protection Agency, December 1993, 

available at https://archive.epa.gov/ttn/ozone/web/ 

html/index-13.html. 

27E.g., CAA 182(b)(1) and (c)(2)(B); see also CAA 

171(1) (defining RFP as ‘‘such annual incremental 

reductions in emissions of the relevant air pollutant 

as are required by this part or may reasonably be 

required by the Administrator for the purpose of 

ensuring attainment of the applicable national 

ambient air quality standard by the applicable 

date’’). 

28NOX Substitution Guidance, Office of Air 

Quality Planning and Standards, U.S. 

Environmental Protection Agency, December 1993. 

29See id. at 8 (quoting H. Rept. No. 490, 101st 

Cong., 2d Sess. 239 (1990)) (‘‘NOX reductions may 

not be substituted for VOC reductions in a manner 

that delays attainment of the ozone standard or that 

results in lesser annual reductions in ozone 

concentration than provided for in the attainment 

demonstration.’’). 

30See 86 FR 37918, 37923–24 (July 19, 2021). 

31See EPA, ‘‘Guideline for Determining the 

Applicability of Nitrogen Oxide Requirements 

under Section 182(f)’’ (December 16, 1993), 1; 

Memorandum dated January 14, 2005, from 

Stephen D. Page, Director, Office of Air Quality 

Planning and Standards, U.S. EPA, to EPA Regional 

Air Directors, Regions I–X, Subject: ‘‘Guidance on 

Limiting Nitrogen Oxides (NOX) Requirements 

Related to 8-Hour Ozone Implementation,’’ 3; EPA– 

454/R–18–004, ‘‘Technical Guidance for 

Demonstration of Inter-Precursor Trading (IPT) for 

Ozone in the Nonattainment New Source Review 

Program,’’ Office of Air Quality Planning and 

Standards (May 2018) (‘‘IPT Guidance’’), 2. The IPT 

Guidance specifically excludes applicability to RFP 

demonstrations. IPT Guidance at 2, n.1. 

area based on a one to one substitution 

ratio, and the underlying requirement in 

CAA section 182(c)(2)(C) has been met. 

The EPA disagrees with the 

commenter’s suggestion that our 

approval relies on demonstration of 

equivalence at a ‘‘a single monitoring 

site’’ and is therefore contrary to the 

CAA. As explained in this notice, this 

demonstration includes the analysis of 

isopleth graphs for both the Palm 

Springs-Fire Station and Indio-Jackson 

Street monitoring sites, which are the 

only two monitoring sites in the 

Coachella Valley nonattainment area. 

Moreover, the EPA disagrees that CAA 

section 182(c)(2)(C)’s use of the term 

‘‘ozone concentrations’’ warrants the 

narrow interpretation that equivalence 

must be specifically demonstrated 

throughout a nonattainment area. As an 

initial matter, we note that the Act 

commonly uses the term 

‘‘concentrations’’ to refer generally to 

ambient pollution levels at one or more 

(but not necessarily multiple) monitors 

or locations.25 CAA section 182(c)(2)(C) 

grants the EPA discretion to define the 

conditions under which NOX reductions 

may be substituted for or combined with 

VOC reductions ‘‘in order to maximize 

the reduction in ozone air pollution’’ 

and does not further specify the 

conditions that represent an 

‘‘equivalent’’ reduction in ozone; for 

instance, it does not require a specific 

concentration test at every monitor or at 

specific locations within an area.26 No 

such requirement appears in the Act’s 

other provisions governing the RFP 

demonstration, which define specific 

percentage reductions aimed at ensuring 

timely attainment of the NAAQS,27 or in 

the EPA’s 1993 NOX Substitution 

Guidance, which describes a 

recommended procedure for states to 

follow to utilize NOX substitution.28 We 

interpret CAA section 182(c)(2)(C) and 

these supporting authorities as properly 

reflecting Congress’ intent to allow NOX

reductions to be considered to substitute 

for the required VOC reductions so long 

as these reductions are at least as 

effective in reducing ozone 

concentrations and consistent with the 

area’s demonstration of timely 

attainment.29

Further, we believe that the 

commenter’s comparison to the EPA’s 

requirements and recommendations for 

interpollutant trading and exemption 

from NOX requirements under CAA 

182(f) misunderstands the purpose of 

and requirements for NOX substitution 

under CAA 182(c)(2)(B) relative to these 

other examples. First, interpollutant 

trading is no longer allowed for ozone.30

Second, the guidance documents cited 

by the commenter for these examples 

are non-binding and do not constrain 

the EPA’s discretion to adopt a different 

approach where appropriate.31 The 

documents recommend photochemical 

grid modeling in some scenarios but do 

not require this approach or any other 

specific demonstration. This reflects the 

EPA’s acknowledgement that the level 

of analysis required for any particular 

demonstration related to NOX and VOC 

reductions will differ based on context 

and local conditions, such as those 

noted by the commenter regarding the 

relative effectiveness of controlling 

each. In the context of CAA 182(c)(2)(C), 

in an area where isopleths generated 

through photochemical grid modeling 

and accompanying analysis indicate 

that the VOC reductions required under 

CAA 182(c)(2)(B) will be less effective 

for reducing ozone concentrations than 

a corresponding percentage reduction in 

NOX emissions, no additional modeling 

or demonstration is required. 

For the reasons described herein, the 

EPA disagrees that additional 

justification is needed to show that 

equal percentage reductions of NOX

emissions can substitute for VOC 

emissions to meet the CAA 

requirements for RFP in this context. 

We find that the District has provided 

ample evidence to demonstrate that 

NOX reductions will be more effective at 

reducing ozone concentrations in 

Coachella Valley, and that the 

photochemical grid modeling conducted 

for the attainment demonstration, in 

combination with the supporting 

analysis accompanying the control 

strategy and other demonstrations, is 

sufficient to support the District’s use of 

NOX substitution. 

Comment #3: ALFA faults the EPA’s 

NOX Substitution Guidance, contending 

that it recommends a procedure that 

fails to demonstrate any equivalence 

between VOC and NOX reductions, as 

required by CAA Section 182(c)(2)(C); 

relies on incorrect policy assumptions; 

and gives legal justifications that are 

without merit. 

Response to Comment #3: Comments 

relating solely to the NOX Substitution 

Guidance are outside the scope of this 

rulemaking action. Our proposed 

approval of the Plan’s use of NOX

substitution is consistent with the 

recommended approach outlined in the 

NOX Substitution Guidance, which, 

while non-binding and not having the 

force of regulation, provides a 

recommended procedure for 

substituting NOX emissions reductions 

for VOC reductions on a percentage 

basis, consistent with a state’s ozone 

attainment plan, control strategy, 

modeled attainment demonstration, and 

RFP milestones and requirements. As 

noted in our response to Comment #2 

above, our approval of the District’s use 

of NOX substitution is supported by 

local conditions and needs as 

documented in the modeling and 

analysis included in the Coachella 

Valley Ozone Plan and the 2016 

AQMP’s use of NOx substitution in this 

RFP demonstration is consistent with 

the requirements of CAA 182(c)(2)(C) for 

the reasons described in this notice. 

III. The EPA’s Action 

Pursuant to section 110(k)(3) of the 

CAA, and for the reasons provided in 

our April 16, 2024 proposed rule and 

this final action and response to 

comments, the EPA is taking final action 

to approve into the California SIP the 

RFP demonstration of the ‘‘Final 

Coachella Valley Extreme Area Plan for 

the 1997 8-Hour Ozone Standard,’’ 

dated December 2020, as meeting the 

requirements of CAA sections 172(c)(2) 

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

51.1105(a)(1) and 51.1100(o)(4). 

In addition, the EPA is taking final 

action to approve CARB’s ‘‘2020 

Coachella Valley Vehicle Miles Traveled 

Emissions Offset Demonstration,’’ 

release date January 22, 2021, as 

meeting the requirements of CAA 


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Federal Register / Vol. 90, No. 12 / Tuesday, January 21, 2025 / Rules and Regulations 6827 

32 89 FR 49815, 49816. 

section 182(d)(1)(A) and 40 CFR 

51.1105(a)(1) and 51.1100(o)(10). 

IV. 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 action merely 

approves State law as meeting Federal 

requirements and does not impose 

additional requirements beyond those 

imposed by State law. For that reason, 

this 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 14094 (88 FR 

21879, April 11, 2023); 

• 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 subject to Executive Order 

13045 (62 FR 19885, April 23, 1997) 

because it approves a State program; 

• Is not a significant regulatory action 

subject to Executive Order 13211 (66 FR 

28355, May 22, 2001); and 

• 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 

applications of those requirements 

would be inconsistent with the Clean 

Air Act. 

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 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). 

Executive Order 12898 (Federal 

Actions to Address Environmental 

Justice in Minority Populations and 

Low-Income Populations, 59 FR 7629, 

February. 16, 1994) directs Federal 

agencies to identify and address 

‘‘disproportionately high and adverse 

human health or environmental effects’’ 

of their actions on communities with 

environmental justice (EJ) concerns to 

the greatest extent practicable and 

permitted by law. Executive Order 

14096 (Revitalizing Our Nation’s 

Commitment to Environmental Justice 

for All, 88 FR 25251, April 26, 2023) 

builds on and supplements Executive 

Order 12898 and defines EJ as, among 

other things, ‘‘the just treatment and 

meaningful involvement of all people, 

regardless of income, race, color, 

national origin, Tribal affiliation, or 

disability, in agency decision-making 

and other Federal activities that affect 

human health and the environment.’’ 

The State did not evaluate EJ 

considerations as part of its SIP 

submittal; the CAA and applicable 

implementing regulations neither 

prohibit nor require such an evaluation. 

Our June 12, 2024 final action on other 

elements of the Plan includes additional 

discussion about how SCAQMD 

responded to comments related to EJ 

concerns during development of the 

Plan.32 The EPA did not perform an EJ 

analysis and did not consider EJ in this 

action. Due to the nature of the action 

being taken here, this action is expected 

to have a neutral to positive impact on 

the air quality of the affected area. 

Consideration of EJ is not required as 

part of this action, and there is no 

information in the record inconsistent 

with the stated goal of Executive Orders 

12898 and 14096 of achieving EJ for 

communities with EJ concerns. 

This action is subject to the 

Congressional Review Act, and the EPA 

will submit a rule report to each House 

of the Congress and to the Comptroller 

General of the United States. This action 

is not a ‘‘major rule’’ as defined by 5 

U.S.C. 804(2). 

Under section 307(b)(1) of the Clean 

Air Act, petitions for judicial review of 

this action must be filed in the United 

States Court of Appeals for the 

appropriate circuit by March 24, 2025. 

Filing a petition for reconsideration by 

the Administrator of this final rule does 

not affect the finality of this action for 

the purposes of judicial review nor does 

it extend the time within which a 

petition for judicial review may be filed 

and shall not postpone the effectiveness 

of such rule or action. This action may 

not be challenged later in proceedings to 

enforce its requirements. (See section 

307(b)(2)). 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Incorporation by 

reference, Intergovernmental relations, 

Nitrogen oxides, Ozone, and Reporting 

and recordkeeping requirements, and 

Volatile organic compounds. 

Dated: January 8, 2025. 

Martha Guzman Aceves, 

Regional Administrator, Region IX. 

For the reasons stated in the 

preamble, the EPA amends Chapter I of 

Title 40 of the Code of Federal 

Regulations as follows: 

PART 52—APPROVAL AND 

PROMULGATION OF 

IMPLEMENTATION PLANS 

■ 1. The authority citation for part 52 

continues to read as follows: 

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

Subpart F—California 

■ 2. Section 52.220 is amended by 

adding paragraphs (c)(614)(ii)(A)(2) and 

(c)(624) to read as follows: 

§ 52.220 Identification of plan—in part. 

* * * * * 

(c) * * * 

(614) * * * 

(ii) * * * 

(A) * * * 

(2) ‘‘South Coast Air Quality 

Management District, Final Coachella 

Valley Extreme Area Plan for the 1997 

8-Hour Ozone Standard,’’ dated 

December 2020, the section titled 

‘‘Reasonable Further Progress,’’ pages 6– 

1 through 6–7. 

* * * * * 

(624) The following plan was 

submitted electronically on March 18, 

2021, by the Governor’s designee as an 

attachment to a letter dated March 15, 

2021. 

(i) [Reserved] 

(ii) Additional materials. 

(A) California Air Resources Board. 

(1) California Air Resources Board, 

Staff Report, ‘‘2020 Coachella Valley 

Vehicle Miles Traveled Emissions Offset 

Demonstration,’’ Release Date: January 

22, 2021. 

(2) [Reserved] 

(B) [Reserved] 

[FR Doc. 2025–01110 Filed 1–17–25; 8:45 am] 

BILLING CODE 6560–50–P 


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