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1See 40 CFR 81.302. 

2We note that Alaska submitted a SIP revision on 

October 25, 2018, to address the preconstruction 

permitting new source review (NSR) requirements 

for the Fairbanks Serious nonattainment area, 

among other things. The EPA approved the 

submission as meeting the nonattainment NSR 

requirements for the Fairbanks Serious Plan on 

August 29, 2019 (84 FR 45419). 

3We note that 18 AAC 50.030(a) is not submitted, 

rather Alaska submits the adopted provisions 

separately for EPA approval. 

4 40 CFR 51.1003(c). 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R10–OAR–2024–0595; FRL–12391– 

02–R10] 

Air Plan Approval; AK, Fairbanks North 

Star Borough; 2006 24-Hour PM2.5

Serious Area and 189(d) Plan 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is proposing to approve 

the state implementation plan (SIP) 

revisions submitted by the State of 

Alaska (Alaska or the State) on 

December 4, 2024, to address Clean Air 

Act requirements for the 2006 24-hour 

fine particulate matter (PM2.5) national 

ambient air quality standards in the 

Fairbanks North Star Borough Serious 

PM2.5 nonattainment area. Alaska’s 

submission includes SIP revisions to 

meet nonattainment planning 

requirements for emissions inventories, 

modeling and sulfur dioxide precursor 

demonstration for major stationary 

sources, control measures, attainment 

projections and progress to attainment 

and associated motor vehicle emissions 

budgets, and contingency measures. The 

EPA is also starting the adequacy 

process for the budgets. 

DATES: Comments. Written comments 

must be received on or before February 

7, 2025. 

ADDRESSES: Submit your comments, 

identified by Docket ID No. EPA–R10– 

OAR–2024–0595, at https://

www.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 the disclosure of which 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, 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. 

FOR FURTHER INFORMATION CONTACT: 

Matthew Jentgen, EPA Region 10, 1200 

Sixth Avenue, Suite 155, Seattle, WA 

98101, (206) 553–0340, 

jentgen.matthew@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Throughout this document wherever 

‘‘we,’’ ‘‘us,’’ or ‘‘our’’ is used, it is 

intended to refer to the EPA. 

Table of Contents 

I. Background 

II. Review of the SIP Revisions to the 

Fairbanks Serious Plan and Fairbanks 

189(d) Plan 

A. Emissions Inventory 

B. Pollutants Addressed 

C. Control Strategy 

D. Attainment Demonstration and 

Modeling 

E. Reasonable Further Progress 

F. Quantitative Milestones 

G. Contingency Measures 

H. Motor Vehicle Emission Budgets for 

Transportation Conformity 

III. Summary of Proposed Action 

A. Proposed Approval 

B. Adequacy Process 

IV. Interim Final Determination and Deferral 

of Sanctions 

V. Incorporation by Reference 

VI. Statutory and Executive Order Reviews 

I. Background 

In 2009, the EPA designated a portion 

of the Fairbanks North Star Borough as 

‘‘nonattainment’’ for the 2006 24-hour 

PM2.5 National Ambient Air Quality 

Standards (NAAQS), which is set at the 

level of 35 micrograms per cubic meter 

(mg/m3) (Fairbanks PM2.5 Nonattainment 

Area) (74 FR 58688, November 13, 

2009).1 Effective July 2, 2014, the EPA 

classified the area as ‘‘Moderate’’ (79 FR 

31566, June 2, 2014). Subsequently, 

Alaska submitted, and the EPA 

approved, a plan to meet the Moderate 

nonattainment area requirements (82 FR 

42457, September 8, 2017) (Fairbanks 

Moderate Plan). 

On May 10, 2017, the EPA determined 

that the Fairbanks PM2.5 Nonattainment 

Area failed to attain the 2006 24-hour 

PM2.5 NAAQS in the area by the 

outermost statutory Moderate area 

attainment date of December 31, 2015 

(82 FR 21711). The outermost 

attainment date is the latest date by 

which an area can attain the NAAQS 

per statute. As a result, the Fairbanks 

PM2.5 Nonattainment Area was 

reclassified as a ‘‘Serious’’ 

nonattainment area by operation of law. 

Upon reclassification as a Serious 

PM2.5 nonattainment area, the State was 

required to submit a Serious area 

attainment plan satisfying the 

requirements of Clean Air Act (CAA or 

Act) sections 172, 189(b), and 189(c) 

and 40 CFR 51.1003(b). In accordance 

with CAA section 188(c)(2), the 

outermost attainment date for a Serious 

area is no later than the end of the tenth 

calendar year following designation 

(i.e., December 31, 2019). 

Alaska submitted a plan to address 

the Serious PM2.5 nonattainment area 

requirements on December 13, 2019 

(Fairbanks Serious Plan).2 Along with 

the required planning elements, the 

Fairbanks Serious Plan included more 

stringent performance and operating 

requirements for residential and 

commercial heating devices, new 

regulations for wood sellers, and some 

requirements for stationary sources in 

the nonattainment area. The Fairbanks 

Serious Plan is comprised of revisions 

to Title 18, Chapter 50, of the Alaska 

Administrative Code (18 AAC 50) and 

the State Air Quality Control Plan, 

adopted and incorporated by reference 

into State law at 18 AAC 50.030(a).3 On 

January 9, 2020, in accordance with 

CAA section 110(k)(1)(B), the EPA 

determined that the Fairbanks Serious 

Plan was administratively and 

technically complete (85 FR 7760, 

February 11, 2020). 

Within the Fairbanks Serious Plan, 

the State sought an extension of the 

otherwise applicable attainment date 

through CAA section 188(e). On 

September 2, 2020, the EPA determined 

that the area failed to attain by the 

Serious area attainment date and denied 

the State’s Serious area attainment date 

extension request (85 FR 54509). As a 

result, Alaska was required to submit a 

revised SIP submission to meet both the 

Serious area attainment plan 

requirements and the additional 

requirements set forth in CAA section 

189(d) by December 31, 2020.4 Alaska 

submitted the revised plan on December 

15, 2020 (Fairbanks 189(d) Plan). The 

Fairbanks 189(d) Plan updated a 

number of chapters of the narrative 

portion of the State Air Quality Control 

Plan, adopted and incorporated by 

reference into State law at 18 AAC 

50.030(a). 

On September 24, 2021, the EPA 

approved the 2013 base year emissions 

inventory and the PM2.5 precursor 


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5State Air Quality Control Plan, Vol. II, section 

III.D.7.12 (i.e., Alaska’s planning chapter related to 

air quality forecasting and curtailment levels). 

6For a description of the specific control 

measures addressed across the State’s SIP 

submissions, see 86 FR 52997, September 24, 2021. 

7 88 FR 84626, December 5, 2023. 

demonstration elements of the 

Fairbanks Serious Plan as meeting the 

Serious area planning requirements (86 

FR 52997). In the same action, the EPA 

approved other plan components as SIP 

strengthening, including: (1) the 

updated Fairbanks Emergency Episode 

Plan 5 that the State adopted on 

November 18, 2020, and submitted on 

December 15, 2020; and (2) the 

regulatory control measures included in 

the SIP submissions on October 25, 

2018, and November 28, 2018 (in 

addition to the December 13, 2019, 

submission).6 The EPA did not 

determine as part of the September 24, 

2021, approval whether these SIP 

strengthening components met specific 

nonattainment plan requirements, 

including control strategy requirements 

in CAA section 189 and 40 CFR 51.1010 

or the contingency measure 

requirements in CAA section 172(c)(9) 

and 40 CFR 51.1014. 

Finally, on December 5, 2023, the 

EPA acted on the remaining elements 

required for a Serious nonattainment 

area that failed to attain by the Serious 

area attainment date. Table 1 of this 

preamble provides a summary of the 

December 5, 2023, final rule approving 

in part and disapproving in part the 

Fairbanks Serious Plan and Fairbanks 

189(d) Plan.7

TABLE 1—SUMMARY OF THE EPA’S DECEMBER 5, 2023, FINAL RULE

Description of CAA planning requirement Approval Disapproval 

Base year emissions inventory for Serious areas subject to 

CAA section 189(b) * (CAA section 172(c)(3); 8 40 CFR 

51.1008(b)(1)).

Approval of the 2013 base year emissions inventory.

Base year emissions inventory for areas subject to CAA 

section 189(d) (CAA section 172(c)(3); 40 CFR 

51.1008(c)(1)).

Approval of the 2019 base year emissions inventory.

Attainment projected emissions inventory (CAA section 

172(c)(1); 9 40 CFR 51.1008(c)(2)).

................................................................................. Disapproval. 

Serious area nonattainment plan control strategy that ensures that best available control measures (BACM), including best available control technologies (BACT), for the 

control of direct PM2.5 and PM2.5 precursors are implemented in the nonattainment area (CAA section 

189(b)(1)(B); 10 40 CFR 51.1010(a)).

Partial approval of the control strategy as meeting 

BACM and BACT requirements under CAA section 189(b)(1)(B) 11 and 40 CFR 51.1010(a) for 

the solid fuel home heating device source category and residential and commercial fuel oil 

combustion source category; 

Partial approval of the control strategy approved 

as meeting BACM and BACT requirements 

under CAA section 189(b)(1)(B) 12 and 40 CFR 

51.1010(a) for the charbroiler, used oil burner, 

and mobile source categories (except for rejection of vehicle anti-idling requirements); 

Approval of specific regulations under 18 AAC 

50.075 through 077 (except the requirements 

for dry wood sellers under 18 AAC 50.076(k)), 

and Fairbanks Emergency Episode Plan (except the contingency measure portion); 

Disapproval of the control strategy BACM and 

BACT requirements (CAA section 

189(b)(1)(B) 13 and 40 CFR 51.1010(a)) for the 

following emissions source categories: (1) Requirements for wood sellers; (2) Coal-fired heating devices; (3) Coffee roasters; (4) Weatherization and energy efficiency measures; (5) Mobile source category (disapproving for lack of 

vehicle anti-idling requirements); 

Disapproval of the control strategy BACM and 

BACT requirements (CAA section 

189(b)(1)(B) 14 and 40 CFR 51.1010(a)) for 

PM2.5 and sulfur dioxide (SO2) for the DoyonFort Wainwright Central Heating and Power 

Plant, University of Alaska Fairbanks Campus 

Power Plant, Zehnder Power Plant, and North 

Pole Power Plant. 

Partial approval as meeting applicable control 

strategy BACM and BACT requirements (CAA 

section 189(b)(1)(B) and 40 CFR 51.1010(a)) 

for ammonia (NH3) for the Chena Power Plant, 

Doyon-Fort Wainwright Central Heating and 

Power Plant, University of Alaska Fairbanks 

Campus Power Plant, Zehnder Power Plant, 

and North Pole Power Plant; 

Partial approval of Alaska’s PM2.5 and NH3 BACT 

determinations for the Doyon-Fort Wainwright 

Central Heating and Power Plant; PM2.5 and 

NH3 BACT determination for the University of 

Alaska Fairbanks Campus Power Plant, except 

for the three small diesel fired engines (EUs 23, 

26, and 27); PM2.5 and NH3 BACT determinations for the Zehnder Power Plant; PM2.5 and 

NH3 BACT determinations for the North Pole 

Power Plant.

Additional measures (beyond those already adopted in previous nonattainment plan SIP submissions for the area as 

RACM/RACT, BACM/BACT, and Most Stringent Measures (MSM) 15 (if applicable)) that provide for attainment 

of the NAAQS as expeditiously as practicable and, from 

the date of such submission until attainment, demonstrate 

that the plan will at a minimum achieve an annual five 

percent reduction in emissions of direct PM2.5 or any 

PM2.5 plan precursor. (CAA section 189(d); 16 40 CFR 

51.1010(c)).

................................................................................. Disapproval. 

Attainment demonstration and modeling (CAA sections 

188(c)(2) and 189(b)(1)(A); 17 40 CFR 51.1003(c) and 

51.1011).

................................................................................. Disapproval. 

Reasonable further progress (RFP) provisions (CAA section 

172(c)(2); 18 40 CFR 51.1012).

................................................................................. Disapproval. 

Quantitative milestones (CAA section 189(c); 19 40 CFR 

51.1013).

................................................................................. Disapproval. 


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8 42 U.S.C. 7502(c)(3). 

9 42 U.S.C. 7502(c)(1). 

10 42 U.S.C. 7513a(b)(1)(B). 11 42 U.S.C. 7513a(b)(1)(B). 12 Id. 13 42 U.S.C. 7513a(b)(1)(B). 14 42 U.S.C. 7513a(b)(1)(B). 15MSM is applicable if the EPA has previously 

granted an extension of the attainment date under 

CAA section 188(e) for the nonattainment area and 

NAAQS at issue. The EPA denied Alaska’s request 

to extend the Serious area attainment date for the 

Fairbanks PM2.5 Nonattainment Area. 16 42 U.S.C. 7513a(d). 17 42 U.S.C. 7513(c)(2) and 7513a(b)(1)(A). 18 42 U.S.C. 7502(c)(2). 19 42 U.S.C. 7513a(c). 20 42 U.S.C. 7513a(e). 21 42 U.S.C. 7502(c)(9). 22 42 U.S.C. 7502(c)(9). 23The EPA finalized a limited approval of the 

Fairbanks Emergency Episode Plan, State Air 

Quality Control Plan, Vol. II, section III.D.7.12, as 

SIP-strengthening on September 24, 2021. 86 FR 

52997, September 24, 2021, at pp. 52997, 53004. 24 42 U.S.C. 7502(c)(5), 7513a(b)(3), 7513a(d), and 

7513a(e). 

25See ‘‘SIP Submittal Checklist for the Fairbanks 

North Star Borough PM2.5 Nonattainment Area— 

2024 SIP revision,’’ EPA Region 10, Air and 

Radiation Division, included in the docket for this 

action. 26Fine Particulate Matter National Ambient Air 

Quality Standards: State Implementation Plan 

Requirements, 81 FR 58010, August 24, 2016, at p. 

58149. 

TABLE 1—SUMMARY OF THE EPA’S DECEMBER 5, 2023, FINAL RULE—Continued 

Description of CAA planning requirement Approval Disapproval 

Motor vehicle emission budgets (CAA section 176, 40 CFR 

51.1003(d) and 93.118).

................................................................................. Disapproval. 

An adequate evaluation by the state of sources of all four 

PM2.5 precursors for regulation, and implementation of 

controls on all such precursors, unless the state provides 

a demonstration establishing that it is either not necessary 

to regulate a particular precursor in the nonattainment 

area at issue in order to attain by the attainment date, or 

that emissions of the precursor do not make a significant 

contribution to PM2.5 levels that exceed the standard.* 

(CAA section 189(e); 20 40 CFR 51.1006).

Approval of the State’s comprehensive PM2.5 precursor demonstrations for NOX and VOC emissions.

Contingency measures applicable to Serious areas subject 

to CAA section 189(b) (CAA section 172(c)(9); 21 40 CFR 

51.1014).

................................................................................. Disapproval of the contingency measures requirements of CAA section 172(c)(9) 22 and 40 CFR 

51.1014 applicable to Serious areas subject to 

CAA sections 189(b) and 189(d). 

Contingency measures applicable to Serious areas subject 

to CAA section 189(d) (CAA section 172(c)(9); 40 CFR 

51.1014).

................................................................................. The EPA finalized a limited disapproval of the

Fairbanks 189(d) Plan contingency measure because the contingency measure did not fully 

meet the contingency measure requirements of 

CAA section 172(c)(9) and 40 CFR 51.1014 but 

otherwise strengthened the SIP.23

Nonattainment new source review provisions (CAA sections 

172(c)(5), 189(b)(3), 189(d), and 189(e), and 40 CFR 

51.165, 40 CFR 51.1003(b)(1)(viii), and 40 CFR 

51.1003(c)(1)(viii) 24.

Approval.

* The EPA finalized approval of this requirement on September 24, 2021 (86 FR 52997). 

On December 4, 2024, Alaska made a 

SIP submission (Fairbanks Revised 

189(d) Plan) intended to address the 

nonattainment requirements that were 

disapproved as part of the EPA’s 

December 5, 2023, final rule. CAA 

sections 110(a)(1) and (2) and 110(l) 

require each state to provide reasonable 

public notice and opportunity for public 

hearing prior to the adoption and 

submission of a SIP or SIP revision to 

the EPA. To meet this requirement, 

every SIP submission must include 

evidence that the state provided 

adequate public notice and an 

opportunity for a public hearing 

consistent with the EPA’s implementing 

regulations in 40 CFR 51.102. 

On March 11, 2024, Alaska notified 

the public of the opportunity to review 

and comment on proposed regulatory 

changes related to the Fairbanks 

nonattainment area and announced two 

formal public hearings on April 10, 

2024. The public comment period 

closed on May 10, 2024. Later, on 

August 26, 2024, Alaska opened a 

public comment period to solicit public 

review of amendments to numerous SIP 

sections and appendices and to notify 

the public of two hearings scheduled on 

September 26, 2024. On September 20 

and 23, 2024, Alaska opened comment 

periods for the public to review each 

proposed permit revision to implement 

the State’s proposed regulatory changes. 

The comment periods closed on October 

22 and 25, 2024, respectively. The SIP 

submission includes evidence of the 

public notices and copies of written and 

oral comments received, with the State’s 

associated responses. Therefore, we find 

that the submission meets the 

procedural requirements for public 

notice and hearing in CAA sections 

110(a) and 110(l) and 40 CFR 51.102. 

CAA section 110(k)(1)(B) requires the 

EPA to determine whether a SIP 

submission is complete within 60 days 

of receipt. This section also provides 

that any plan that the EPA has not 

affirmatively determined to be complete 

or incomplete will become complete by 

operation of law six months after the 

date of submission. The EPA reviewed 

the submission and finds it complete 

based on the EPA’s SIP completeness 

criteria in 40 CFR part 51, appendix V.25

Section II of this document 

summarizes the EPA’s review of 

Alaska’s SIP submission against the 

relevant CAA requirements. The EPA’s 

technical analysis is detailed in 

technical support documents in the 

docket for this action. 

II. Review of the SIP Revisions to the 

Fairbanks Serious Plan and Fairbanks 

189(d) Plan 

A. Emissions Inventory 

1. Statutory and Regulatory 

Requirements 

CAA section 172(c)(3) requires that 

states submit a comprehensive, 

accurate, and current inventory of actual 

emissions from all sources of the 

relevant pollutant or pollutants in the 

nonattainment area as part of a 

nonattainment plan for such area. On 

August 24, 2016, the EPA finalized 

regulations implementing SIP 

requirements for states with areas 

designated as nonattainment for the 

PM2.5 NAAQS.26 This rule is codified at 

40 CFR part 51, subpart Z and is 

referred to herein as the PM2.5 SIP 

Requirements Rule. The PM2.5 SIP 

Requirements Rule at 40 CFR 51.1008 

contains the requirements for emissions 


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27 81 FR 58010, August 24, 2016, at pp. 58078– 

58079. 

28 ‘‘Emissions Inventory Guidance for 

Implementation of Ozone and Particulate Matter 

National Ambient Air Quality Standards (NAAQS) 

and Regional Haze Regulations,’’ EPA, May 2017 

(‘‘Emissions Inventory Guidance’’), available at: 

https://www.epa.gov/air-emissions-inventories/airemissions-inventory-guidance-implementationozone-and-particulate. 

29 40 CFR 51.1008(b)(1). 

30 40 CFR 51.1008(c)(1). 

31 40 CFR 51.1008. 

32 40 CFR 51.1008(c); (a)(1)(v); 81 FR 58010, 

August 24, 2016, at pp. 58027–29. 

33See CAA section 172(c)(3). 

34The EPA released an update to AP–42 in 

January 2011 that revised the equation for 

estimating paved road dust emissions based on an 

updated data regression that included new 

emissions tests results. 76 FR 6328 (February 4, 

2011). 

35AP–42 has been published since 1972 as the 

primary source of the EPA’s emission factor 

information. https://www.epa.gov/airemissionsfactors-and-quantification/ap-42- 

compilation-airemissions-factors. It contains 

emission factors and process information for more 

than 200 air pollution source categories. A source 

category is a specific industry sector or group of 

similar emitting sources. The emission factors have 

been developed and compiled from source test data, 

material balance studies, and engineering estimates. 

36State Air Quality Control Plan, Vol. II, section 

III.D.7.6.9. 

inventories.27 The EPA has also issued 

additional guidance concerning 

emissions inventories for PM2.5

nonattainment areas.28 In accordance 

with 40 CFR 51.1008, the attainment 

plan must include a base year emissions 

inventory and attainment projected 

emissions inventory. 

The base year emissions inventory for 

a Serious PM2.5 nonattainment area 

must be one of the three years for which 

the EPA used monitored data to 

reclassify the area to Serious, or another 

technically appropriate year justified by 

the state in its Serious area 

nonattainment plan SIP submission.29

Similarly, the base year emissions 

inventory for a nonattainment area 

subject to CAA section 189(d) must be 

one of the three years for which 

monitored data were used by the EPA to 

determine the area failed to attain the 

PM2.5 NAAQS by the applicable Serious 

area attainment date, or another 

technically appropriate year justified by 

the state in its Serious area 

nonattainment plan SIP submission.30

The base year emissions inventory 

should provide a state’s best estimate of 

actual emissions from all sources, i.e., 

all emissions that contribute to the 

formation of PM2.5. The emissions must 

be either annual total emissions, 

average-season day emissions, or both, 

as appropriate for the relevant annual 

versus 24-hour PM2.5 NAAQS. The state 

must include a rationale for providing 

annual or seasonal emissions 

inventories, and justification for the 

period used for any seasonal emissions 

calculations.31

According to 40 CFR 51.1008, the 

Fairbanks Revised 189(d) Plan must 

include an attainment projected 

inventory for the nonattainment area. 

The year of the projected inventory shall 

be the most expeditious year for which 

projected emissions show modeled 

PM2.5 concentrations below the level of 

the NAAQS. The emissions values shall 

be projected emissions of the same 

sources included in the base year 

inventory for the nonattainment area 

(i.e., those only within the 

nonattainment area) and any new 

sources. The state shall include in this 

inventory projected emissions growth 

and contraction from both controls and 

other causes during the relevant period. 

The temporal period of emissions shall 

be the same temporal period (annual, 

average-season-day, or both) as the base 

year inventory for the nonattainment 

area. The same sources reported as point 

sources in the base year inventory for 

the nonattainment area shall be 

included as point sources in the 

attainment projected inventory for the 

nonattainment area. Stationary nonpoint 

and mobile source projected emissions 

shall be provided using the same detail 

(e.g., state, county, and process codes) 

as the base year inventory for the 

nonattainment area. The same detail of 

the emissions included shall be 

consistent with the level of detail and 

data elements as in the base year 

inventory for the nonattainment area 

(i.e., as required by 40 CFR part 51, 

subpart A). Consistent with the base 

year inventory for the nonattainment 

area, the inventory shall include direct 

PM2.5 emissions, separately reported 

PM2.5 filterable and condensable 

emissions, and emissions of the 

scientific PM2.5 precursors, including 

precursors that are not significant PM2.5

plan precursors pursuant to a precursor 

demonstration under 40 CFR 51.1006. 

A state’s SIP submission must include 

documentation explaining how it 

calculated emissions data for the 

inventory and be consistent with the 

data elements required by 40 CFR part 

51, subpart A.32 In estimating mobile 

source emissions, a state must use the 

latest emissions models and planning 

assumptions available at the time the 

SIP is developed.33 States are also 

required to use the EPA’s ‘‘Compilation 

of Air Pollutant Emission Factors’’ 

(‘‘AP–42’’) road dust method for 

calculating re-entrained road dust 

emissions from paved roads.34 35

2. Summary of the EPA’s Prior 

Rulemaking Regarding the Emissions 

Inventory 

On December 5, 2023, the EPA 

finalized approval of the base year 

emissions inventory, but the EPA 

finalized disapproval of the projected 

attainment year emissions inventory. 

The EPA stated that, due to the 

insufficient control strategy, the 

attainment projected emissions 

inventory did not necessarily take into 

consideration all required emissions 

reductions. 

3. Summary of the State’s Submission 

Regarding the Emissions Inventory 

Based on the EPA’s approval of the 

initial Fairbanks 189(d) Plan’s base year 

emissions inventory, Alaska retained 

State Air Quality Control Plan, Vol. II, 

section III.D.7.6.2. However, Alaska has 

since updated the modeling platform 

and included a 2020 base year 

emissions inventory in the Fairbanks 

Revised 189(d) Plan. The modeling 

platform includes key elements such as 

the meteorological modeling, air quality 

modeling, and model emissions 

inventories. The base year planning 

emissions inventory for direct PM2.5 and 

PM2.5 precursors (nitrogen oxides 

(NOX), SO2, volatile organic compounds 

(VOC), and ammonia (NH3)) and the 

documentation for the inventory for the 

Fairbanks PM2.5 Nonattainment Area are 

located in the updated Fairbanks 

Emissions Inventory section.36

For projecting attainment, the 2020 

base year emissions inventory 

incorporates the ambient monitoring 

data used to establish the baseline 

design value. Alaska stated that the 

2020 base year emissions inventory 

accounts for emissions reductions from 

control measures adopted and 

implemented through December 31, 

2019. Projected control measure-driven 

emissions reductions are then applied to 

evaluate the appropriate attainment 

date. Alaska also noted that, for 

planning purposes, the base year 

emissions inventory represents a 

baseline of nonattainment area 

emissions to demonstrate five percent 

per year emissions reductions. 

Alaska stated that the Fairbanks 

Revised 189(d) Plan includes an entirely 

new photochemical modeling platform 

and, for the emissions inventory, 

features a new, more current winter 

2019–2020 modeling episode. Episodic 

emissions for the 2020 base year 

inventory were based on activity 

collected to represent this 74-day 2019– 

2020 period. 


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37For a description of the ‘‘back-cast’’ method, 

see Kotchenruther, Robert. (November 21, 2024). 

Technical support document for Alaska 

Department of Environmental Conservation’s 

amendments to: State Air Quality Control Plan, 

Emission Inventory Data (version August 19, 2024). 

U.S. Environmental Protection Agency, Region 10, 

Laboratory Services and Applied Science Division, 

EPA–R10–OAR–2024–0595, section 1.5. 

38For more details of the 2019 base year 

emissions inventory, see 88 FR 1454, January 10, 

2023, at p. 1460. 

For point sources, day- and hourspecific fuel use for the new 2019–2020 

modeling episode were obtained by 

Alaska from each of the point source 

facilities within the nonattainment area. 

Alaska noted that unlike the base year 

emissions inventories from earlier 

versions of the nonattainment plan, 

which projected episodic emissions 

from 2008 to 2013 and 2019, 

respectively, Alaska stated that the 2020 

base year point source emissions 

inventory was based on the actual data 

during the modeling episodes. 

Alaska stated that, for space heating 

area sources, space heating energy usage 

estimates for the 2020 base year 

emissions inventory were based on a 

comprehensive new Fairbanks Home 

Heating survey, conducted in the spring 

of 2023. Respondents were asked to 

provide information on fuel usage by 

device in their household for the most 

recent two calendar years (2021 and 

2022) as well as the six-month winter 

period between October 2022 and 

March 2023. Data from this 2023 survey 

were used to replace projected space 

heating emissions developed under 

previous SIP revisions using earlier 

2011–2015 surveys. Alaska noted that 

decreases in the fraction of wood 

devices used in the nonattainment area 

and the amount of wood use per device 

from the survey respondents tracked 

well with downward trajectories of 

wood use expected from existing and 

on-going control programs such as the 

Fairbanks North Star Borough’s (FNSB) 

Wood Stove Change Out Program and 

the Alaska DEC’s Solid Fuel-Burning 

Appliance Curtailment Program. Alaska 

stated that survey results were then 

back-casted to calendar year 2020 to 

provide a more realistic estimate of 

wood-fired heating use for the 2020 base 

year emissions inventory.37

For on-road and non-road mobile 

sources, Alaska noted that the previous 

base year emissions inventories 

included on-road vehicle populations 

and age distributions based on 2014 and 

2018 department of motor vehicle 

(DMV) registration data, respectively. 

For the Fairbanks Revised 189(d) Plan, 

2020 DMV registration data were used 

to align with the 2020 base year 

emissions inventory year. For on-road 

mobile sources, these 2020 DMV data 

were used to develop vehicle 

population, age distribution, and fuel 

type/technology inputs to the MOVES3 

vehicle emissions model. For aircraft 

activity specifically, a recent adjustment 

to aircraft activity in the initial 

Fairbanks 189(d) Plan was made to 

reflect lower aircraft activity during the 

winter months. Otherwise, the estimates 

of aircraft activity in the Fairbanks 

Revised 189(d) Plan were unchanged. 

Table 2 of this preamble includes a 

summary of the base year emissions 

inventory. 

TABLE 2—2020 BASE YEAR EPISODE AVERAGE DAILY EMISSIONS BY SOURCE SECTOR

Source sector 

2020 base year emissions inventory 

(tons/day) 

PM2.5 NOX SO2 VOC NH3

Point Sources ............................................................................................................... 0.58 13.54 6.63 0.04 0.888 

Area, Space Heating .................................................................................................... 1.97 2.17 3.61 6.66 0.109 

Area, Space Heat, Wood ............................................................................................. 1.89 0.23 0.04 6.55 0.067 

Area, Space Heat, Oil .................................................................................................. 0.06 1.72 3.54 0.10 0.003 

Area, Space Heat, Coal ............................................................................................... 0.00 0.00 0.00 0.00 0.00 

Area, Space Heat, Other ............................................................................................. 0.02 0.22 0.02 0.01 0.039 

Area, Other .................................................................................................................. 0.11 0.36 0.03 2.21 0.047 

Mobile, On-Road .......................................................................................................... 0.07 1.18 0.000 1.42 0.040 

Mobile, Aircraft ............................................................................................................. 0.12 0.43 5.44 0.15 0.000 

Mobile, Non-Road excluding aircraft ........................................................................... 0.09 0.29 0.00 2.64 0.0001 

Totals .................................................................................................................... 2.95 17.96 15.71 13.04 0.285 

Source: State Air Quality Control Plan, Vol. II, section III.D.7.6, Table 7.6–9. 

Alaska noted for PM2.5 overall, the 

2020 base year emissions in the 

Fairbanks Revised 189(d) Plan are nine 

percent lower than the 2019 base year 

emissions inventory in the initial 

Fairbanks 189(d) Plan, with differences 

coming from space heating and mobile 

sources that are likely the result of ongoing emissions controls.38

Alaska stated that NOX and SO2

emissions in the Fairbanks Revised 

189(d) Plan are 17 and nine percent 

higher respectively than in the initial 

Fairbanks 189(d) Plan. Alaska asserted 

that these emissions increases are 

largely driven by changes in the Point 

(and Other Area) source emissions, 

since the new 74-day 2019–2020 

modeling episode was based on actual 

emissions. In addition, the increases in 

NOX and SO2 emissions for the Other 

Area source sector under the Fairbanks 

Revised 189(d) Plan are due to moving 

stationary source emissions from 

Eielson AFB to this sector. Under the 

previous base year emissions 

inventories, stationary source emissions 

from Eielson were contained in the 

Point source portion of the inventory. 

The reductions in VOC emissions in 

the Fairbanks Revised 189(d) Plan are 

due to mobile source sector reductions 

in the MOVES3 model. The initial 

Fairbanks 189(d) Plan inventory was 

based on an earlier version of MOVES 

that reflected higher VOC emission 

factors. In addition, Alaska stated that 

VOC reductions in the Space Heating 

sector are likely the result of differences 

in the mix of wood use by device 

between the two inventories. The 

Fairbanks Revised 189(d) Plan inventory 

reflects higher usage fractions of 

certified and pellet-based wood burning 

devices based on data from new 2023 

Home Heating survey, and these devices 

have lower VOC emission factors. 

Finally, Alaska noted that the 

difference in overall NH3 emissions 

between the two base year inventories is 

very modest (one percent lower under 


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39State Air Quality Control Plan, Vol. II, section 

III.D.7.6, Table 7.6–11. 

40 Kotchenruther, Robert. (November 21, 2024). 

Technical support document for Alaska 

Department of Environmental Conservation’s 

amendments to: State Air Quality Control Plan, 

Emission Inventory Data (version August 19, 2024). 

U.S. Environmental Protection Agency, Region 10, 

Laboratory Services and Applied Science Division, 

EPA–R10–OAR–2024–0595. 

the Fairbanks Revised 189(d) base year 

emissions inventory). These source 

sector-specific variations mirror the 

adjustments made to PM2.5, SO2, NOX, 

and VOC emissions discussed earlier in 

this section II.A of this preamble. 

Building from Alaska’s new 2020 base 

year emissions inventory, Alaska 

developed its attainment projections. As 

a first step, Alaska constructed a 2027 

baseline emissions inventory that 

reflected projected activity growth 

factors, previously implemented control 

measures, and other adjustments to 

point sources and wood usage.39

As a second step, Alaska developed 

the 2027 projected attainment emissions 

inventory by adjusting the 2027 baseline 

inventory to account for projected 

emissions reductions from the control 

strategy included in the Fairbanks 

Revised 189(d) Plan. For a complete list 

of measures included in Alaska’s 

control strategy, see Table 4 in section 

II.D of this preamble below. Notably, as 

part of the control strategy, the Wood 

Stove Change Out Program and the OilTo-Gas Conversion Program are 

managed by the local Fairbanks North 

Star Borough. Direct PM2.5 reductions 

from these programs in 2020 through 

2026 totaled over 1.3 tons per episode 

day. The State of Alaska manages the 

Solid Fuel-Burning Appliance 

Curtailment Program as well as seven 

other control measures for which 

emissions benefits were quantified and 

incorporated into the 2027 attainment 

projected inventory. Notably, the State 

recently increased the stringency of the 

curtailment program by lowering the 

alert stages to 20 mg/m3 and 30 mg/m3, 

respectively. Alaska also utilized 

funding from the 2019–2020 Targeted 

Airshed Grant (TAG) to purchase three 

dynamic message highway signs and an 

infrared camera and to expand staffing 

to increase compliance. For details of 

these projected emissions reductions, 

see the spreadsheet calculations in the 

State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.6. 

Alaska concluded that, after 

considering the emissions reductions 

from these control measures, the 

Fairbanks PM2.5 Nonattainment Area 

could demonstrate attainment by 2027, 

based on the 2027 attainment year 

emissions inventory, as summarized in 

Table 3 of this preamble. 

TABLE 3—2027 PROJECTED ATTAINMENT EMISSIONS INVENTORY, AVERAGE DAILY EMISSIONS BY SOURCE SECTOR

Source sector 

2027 Projected attainment emissions inventory 

(tons/day) 

PM2.5 NOX SO2 VOC NH3

Point Sources ............................................................................................................... 0.62 14.60 7.15 0.04 0.095 

Area, Space Heating .................................................................................................... 0.74 2.34 1.98 8.01 0.124 

Area, Space Heat, Wood ............................................................................................. 0.70 0.28 0.04 7.90 0.081 

Area, Space Heat, Oil .................................................................................................. 0.02 1.83 1.91 0.10 0.004 

Area, Space Heat, Coal ............................................................................................... 0.00 0.00 0.00 0.00 0.00 

Area, Space Heat, Other ............................................................................................. 0.02 0.22 0.02 0.01 0.039 

Area, Other .................................................................................................................. 0.13 0.40 0.03 2.33 0.051 

Mobile, On-Road .......................................................................................................... 0.05 0.65 0.00 1.08 0.038 

Mobile, Aircraft ............................................................................................................. 0.12 0.45 5.70 0.17 0.000 

Mobile, Nonroad excluding aircraft .............................................................................. 0.08 0.32 0.00 2.22 0.002 

Totals .................................................................................................................... 1.74 18.75 14.86 13.85 0.310 

Source: State Air Quality Control Plan, Vol. II, section III.D.7.6, Table 7.6–19. 

Alaska observed that the 2027 

projected attainment emissions 

inventory provides reductions in total 

PM2.5 and SO2 emissions within the 

nonattainment area of 41 percent and 

five percent respectively. Within the 

space heating sector, which has a 

proportionally higher impact on 

ambient PM2.5, Alaska noted that the 

2027 projected attainment emissions 

inventory reductions were 63 percent 

and 45 percent for direct PM2.5 and SO2, 

respectively. 

4. EPA Evaluation and Proposed Action 

Regarding the Emissions Inventory 

a. 2020 Base Year Emissions Inventory 

The EPA proposes to approve the 

2020 base year emissions inventory as 

meeting the requirements of CAA 

section 172(c)(3) and 40 CFR 51.1008. 

The EPA is proposing to determine that 

Alaska has justified that 2020 is a 

technically appropriate inventory year 

consistent with 40 CFR 51.1008(c)(1). 

The base year emissions inventory 

includes actual emissions of all sources 

within the nonattainment area. The EPA 

proposes to determine that a seasonal 

episode daily average inventory is 

appropriate for the Fairbanks PM2.5

Nonattainment Area because the area 

experiences episodic elevated 

concentrations of PM2.5 during 

wintertime cold weather events. The 

emissions inventory includes direct 

PM2.5 emissions, separately reported as 

filterable and condensable emissions, as 

well as all scientific PM2.5 precursors 

(SO2, NOX, VOC, and NH3). Alaska 

reported emissions for point sources 

according to the point source emissions 

thresholds of the Air Emissions 

Reporting Rule in 40 CFR part 51, 

subpart A. Finally, the emissions 

inventory is consistent with the detail 

and data elements required by 40 CFR 

part 51, subpart A. For the EPA’s full 

evaluation, see the EPA’s technical 

evaluation of Alaska’s emissions 

inventory included in the docket for this 

action.40

b. 2027 Projected Attainment Emissions 

Inventory 

The EPA proposes to approve the 

2027 projected attainment emissions 

inventory as meeting the requirements 

of CAA section 172(c)(3) and 40 CFR 

51.1008. The EPA is proposing to 

determine that 2027 is the most 

expeditious year for which projected 

emissions show modeled PM2.5

concentrations below the level of the 

NAAQS. As discussed in section II.D of 

this preamble, Alaska included a model 

output for 2026 that resulted in 

emissions levels exceeding the 2006 24- 


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1606 Federal Register / Vol. 90, No. 5 / Wednesday, January 8, 2025 / Proposed Rules 

41 Kotchenruther, Robert. (November 21, 2024). 

Technical support document for Alaska 

Department of Environmental Conservation’s 

amendments to: State Air Quality Control Plan, 

Emission Inventory Data (version August 19, 2024). 

U.S. Environmental Protection Agency, Region 10, 

Laboratory Services and Applied Science Division, 

EPA–R10–OAR–2024–0595. 

42 40 CFR 51.1006, 51.1010; See 81 FR 58010, 

August 24, 2016, at pp. 58017–58020. 

43CAA section 302(g). 

44 81 FR 58010, August 24, 2016, at p. 58015. 

45 ‘‘Policy Assessment for the Reconsideration of 

the National Ambient Air Quality Standards for 

Particulate Matter’’ (EPA/452/R–22–004), EPA, May 

2022), p. 2–10. 

46The requirements for attainment plans for the 

2006 24-hour PM2.5 NAAQS include the general 

nonattainment area planning requirements in CAA 

section 172 of title I, part D, subpart 1 and the 

additional planning requirements specific to 

particulate matter in CAA sections 188 and 189 of 

title I, part D, subpart 4. 81 FR 58010, August 24, 

2016, at pp. 58012–58014. 

47The general attainment plan requirements of 

subpart 1, part D, of title I of the CAA in addition 

to the specific requirements in subpart 4, part D, of 

Title I of the CAA apply to both PM10 and PM2.5. 

See 81 FR 58010, August 24, 2016, at pp. 58013. 

48 81 FR 58010, August 24, 2016, at pp. 58018– 

58019. 

49State Implementation Plan; General Preamble 

for the Implementation of Title I of the Clean Air 

Act Amendments of 1990 (‘‘General Preamble’’), 57 

FR 13498, April 16, 1992, at pp. 13539–42. 

50 40 CFR 51.1006. See also 81 FR 58010, 58033. 

Courts have upheld this approach to the 

requirements of subpart 4 for PM10. See, e.g., Assoc. 

of Irritated Residents v. EPA, et al., 423 F.3d 989 

(9th Cir. 2005). 

51 40 CFR 51.1006(a)(1). 

52 40 CFR 51.1006(a)(1). 

53 40 CFR 51.1006(a)(2). 

54 40 CFR 51.1006(a)(2)(iii). 

hour PM2.5 NAAQS. The attainment 

projected inventory includes the sources 

in the base year emissions inventory 

and accounts for growth and contraction 

from both controls and other causes. 

Consistent with the base year emissions 

inventory, the attainment projected 

emissions inventory is based on episode 

average daily emissions. The attainment 

projected emissions inventory includes 

direct PM2.5 emissions, separately 

reported as filterable and condensable 

emissions, as well as all scientific 

precursors. The attainment projected 

emissions inventory includes the same 

level of emissions detail for the same 

point sources and for mobile sources 

reported in the base year emissions 

inventory. For the EPA’s full evaluation, 

see the EPA’s technical evaluation of 

Alaska’s emissions inventory, included 

in the docket for this action.41

B. Pollutants Addressed 

1. Statutory and Regulatory 

Requirements Regarding the Pollutants 

Addressed 

Under subpart 4 of part D, title I of the 

CAA and the PM2.5 SIP Requirements 

Rule, each state containing a PM2.5

nonattainment area must evaluate all 

PM2.5 precursors for regulation unless, 

for any given PM2.5 precursor, the state 

demonstrates to the Administrator’s 

satisfaction that such precursor does not 

contribute significantly to PM2.5 levels 

that exceed the NAAQS in the 

nonattainment area.42 The provisions of 

subpart 4 do not define the term 

‘‘precursor’’ for purposes of PM2.5, nor 

do they explicitly require the control of 

any specifically identified PM2.5

precursor. The statutory definition of 

‘‘air pollutant,’’ however, provides that 

the term ‘‘includes any precursors to the 

formation of any air pollutant, to the 

extent the Administrator has identified 

such precursor or precursors for the 

particular purpose for which the term 

‘air pollutant’ is used.’’ 43 The EPA has 

identified SO2, NOX, VOCs, and NH3 as 

precursors to the formation of PM2.5.44

Accordingly, the attainment plan 

requirements of part D, title I of the 

CAA and the PM2.5 SIP Requirements 

Rule apply to emissions of all four 

precursors and direct PM2.5 from all 

types of stationary, area, and mobile 

sources, except as otherwise provided in 

CAA section 189(e)., 

As noted in the EPA’s Final Policy 

Assessment for the reconsideration of 

the PM2.5 NAAQS, secondary 

particulate matter is formed in the 

atmosphere by photochemical oxidation 

reactions of both inorganic and organic 

gas-phase precursors. Precursor gases 

include SO2, NOX, NH3, and VOC gases 

of anthropogenic or natural origin. 

Anthropogenic SO2 and NOX are the 

predominant precursor gases in the 

formation of secondary PM2.5 sulfate 

and nitrate, and NH3 is the gas-phase 

precursor for PM2.5 ammonium. PM2.5

ammonium formation is enhanced by 

particle acidity resulting from sulfuric 

acid and nitric acid condensation onto 

particles. Atmospheric oxidation of 

VOCs, both anthropogenic and biogenic, 

is an important source of organic 

aerosols, particularly in summer. The 

semi-volatile and nonvolatile products 

of VOC oxidation reactions can 

condense onto existing particles or can 

form new particles.45

According to the State, total 

wintertime PM2.5 concentrations in the 

Fairbanks PM2.5 Nonattainment Area are 

a function of both primary PM2.5

emissions and secondary PM2.5 formed 

from precursors (see State Air Quality 

Control Plan, Vol. II, section III.D.7.8.1). 

CAA section 189(e) requires that the 

control requirements for major 

stationary sources of direct PM10 46 and 

PM2.5 47 also apply to major stationary 

sources of PM10 and PM2.5 precursors, 

except where the Administrator 

determines that such sources do not 

contribute significantly to PM10 or PM2.5

levels that exceed the standard in the 

area. CAA section 189(e) contains the 

only express exception to the control 

requirements under subpart 4 (e.g., 

requirements for reasonably available 

control measures (RACM) and 

reasonably available control technology 

(RACT), BACM and BACT, Most 

Stringent Measures (MSM), and New 

Source Review (NSR) for sources of 

direct PM2.5 and PM2.5 precursor 

emissions). Although CAA section 

189(e) explicitly addresses only major 

stationary sources, the EPA interprets 

this provision as authorizing it also to 

determine, under appropriate 

circumstances, that regulation of 

specific PM10 or PM2.5 precursors from 

other source categories in a given 

nonattainment area is not necessary.48

For example, under the EPA’s 

longstanding interpretation of the 

control requirements that apply to 

stationary, area, and mobile sources of 

PM10 precursors in the nonattainment 

area under CAA section 172(c)(1) and 

subpart 4,49 a state may demonstrate in 

a SIP submission that control of a 

certain precursor pollutant is not 

necessary in light of its insignificant 

contribution to ambient PM10 or PM2.5

levels in the nonattainment area.50

Under the PM2.5 SIP Requirements 

Rule, a state may elect to submit to the 

EPA a ‘‘comprehensive precursor 

demonstration’’ for a specific 

nonattainment area to show that 

emissions of a particular precursor from 

all existing sources located in the 

nonattainment area do not contribute 

significantly to PM2.5 levels that exceed 

the NAAQS at issue in the 

nonattainment area.51 If the EPA 

determines that the contribution of the 

precursor to PM2.5 levels in the area is 

not significant and approves the 

demonstration, then the state is not 

required to control emissions of the 

relevant precursor from existing sources 

in the attainment plan.52

Relatedly, under the PM2.5 SIP 

Requirements Rule, a state may submit 

to the EPA a ‘‘major stationary source 

precursor demonstration’’ for a specific 

nonattainment area that shows that 

emissions of a particular precursor from 

all existing major stationary sources 

located in the nonattainment area do not 

contribute significantly to PM2.5 levels 

that exceed the standard in the area.53

If the EPA approves a major stationary 

source precursor demonstration, then 

the state is not required to control 

emissions of the relevant precursor from 

existing major stationary sources in the 

current attainment plan.54


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55 ‘‘PM2.5 Precursor Demonstration Guidance,’’ 

EPA–454/R–19–004, May 2019, including Memo 

dated May 30, 2019, from Scott Mathias, Acting 

Director, Air Quality Policy Division and Richard 

Wayland, Director, Air Quality Assessment 

Division, Office of Air Quality Planning and 

Standards (OAQPS), EPA to Regional Air Division 

Directors, Regions 1–10, EPA. 

56 40 CFR 51.1006(a)(1)(i) and (ii). 

57 88 FR 84626, December 5, 2023, at p. 84675. 

58See State Air Quality Control Plan, Vol. II., 

section III.D.7.8.15, Table 7.8.18–1. 

59 ‘‘PM2.5 Precursor Demonstration Guidance,’’ 

EPA–454/R–19–004, May 2019, including Memo 

dated May 30, 2019, from Scott Mathias, Acting 

Director, Air Quality Policy Division and Richard 

Wayland, Director, Air Quality Assessment 

Division, Office of Air Quality Planning and 

Standards (OAQPS), EPA to Regional Air Division 

Directors, Regions 1–10, EPA. 

60Briggs, Nicole. (December 2, 2024). Review of 

Attainment Demonstration Modeling and SO2

Precursor Demonstration in the 2024 State 

Implementation Plan Submission for the Fairbanks 

24-hour PM2.5 Nonattainment Area. U.S. 

Environmental Protection Agency, Region 10, 

Laboratory Services and Applied Science Division, 

EPA–R10–OAR–2024–0595. 

In addition, in May 2019, the EPA 

issued the ‘‘PM2.5 Precursor 

Demonstration Guidance’’ (‘‘PM2.5

Precursor Guidance’’), which provides 

recommendations to states for analyzing 

nonattainment area PM2.5 emissions and 

developing such optional precursor 

demonstrations, consistent with the 

PM2.5 SIP Requirements Rule.55

The EPA evaluated the Fairbanks 

Revised 189(d) Plan in accordance with 

the presumption embodied within 

subpart 4 that the State must address all 

PM2.5 precursors in the evaluation and 

implementation of potential control 

measures, unless the State adequately 

demonstrates that emissions of a 

particular precursor or precursors do 

not contribute significantly to ambient 

PM2.5 levels that exceed the PM2.5

NAAQS in the nonattainment area. In 

reviewing any determination by the 

state to exclude a PM2.5 precursor from 

the required evaluation of potential 

control measures, we consider both the 

magnitude of the precursor’s 

contribution to ambient PM2.5

concentrations in the nonattainment 

area and the sensitivity of ambient PM2.5

concentrations in the area to reductions 

in emissions of that precursor.56

2. Summary of the EPA’s Prior 

Rulemaking Regarding the Pollutants 

Addressed 

On December 5, 2023, the EPA 

finalized approval of Alaska’s precursor 

demonstration that NOX and VOCs are 

not significant precursors to PM2.5

formation in the Fairbanks PM2.5

Nonattainment Area.57

3. Summary of the State’s Submission 

Regarding the Pollutants Addressed 

In the Fairbanks Revised 189(d) Plan, 

in accordance with 40 CFR 

51.1006(a)(2), Alaska included a 

demonstration that SO2 emissions from 

major stationary sources do not 

significantly contribute to PM2.5

formation in the Fairbanks PM2.5

Nonattainment Area. As discussed in 

the State Air Quality Control Plan, Vol. 

II, section III.D.7.8.15, Alaska stated that 

it utilized a new model platform that 

accurately simulated the formation of 

precursors into PM2.5 in the Fairbanks 

environment. The new model platform 

also demonstrated marked improvement 

in the simulation of sulfate formation 

from SO2 emissions as compared to 

prior platforms used by Alaska. Using 

the new model platform, Alaska 

performed a concentration-based 

contribution analysis using air quality 

modeling with ‘‘zero-out’’ model runs. 

Alaska’s analysis showed that major 

stationary sources contributed 0.21 mg/ 

m3 PM2.5 at regulatory monitoring sites 

in Fairbanks including the North Pole 

monitor (Hurst Road), which is below 

the 1.5 mg/m3 PM2.5 threshold included 

in the EPA’s guidance.58

According to Alaska, the updated 

analysis of precursor impacts on PM2.5

utilized a photochemical grid model 

(PGM) that accounted for the non-linear 

secondary effects of precursor gases. 

PGMs account for the atmospheric 

chemistry, transport, and deposition of 

pollutants using local emissions and 

meteorological data. The zero-out 

approach compared a baseline model 

run with a model run where a 

precursor’s emissions are set to zero to 

determine the influence of that 

precursor on PM2.5 formation. 

Alaska noted that a concentrationbased analysis was completed that 

excluded all sources of SO2. The 

monitored filter sulfate and the 

concentrations from the 5-year design 

value showed total sulfate from all 

sectors was 5.9 mg/m3 or 21 percent of 

the PM2.5 at an air quality monitor 

located in the City of Fairbanks (NCore) 

and 5.9 mg/m3 or nine percent of the 

PM2.5 at the North Pole air quality 

monitor (Hurst Road). When accounting 

for all emissions sources, SO2 remained 

a significant precursor to PM2.5

formation in the Fairbanks PM2.5

Nonattainment Area. 

After completing the first step, the 

major stationary source sector SO2

precursor model runs were then 

performed based on the emissions for 

the 2020 base year and a model run that 

excluded SO2 emissions. The difference 

in sulfate for a model simulation using 

base year emissions and a second model 

simulation with major stationary-source 

SO2 emissions set to zero was compared 

with the 1.5 ug/m3 threshold. Alaska 

stated that this concentration-based 

modeling demonstrated the 

insignificance of SO2 from major 

stationary sources when compared with 

the 1.5 mg/m3 threshold in the EPA’s 

guidance, and therefore, a sensitivitybased contribution analysis was not 

needed, in accordance with 40 CFR 

51.1006(a)(2)(ii). 

4. The EPA’s Evaluation and Proposed 

Action Regarding the Pollutants 

Addressed 

The EPA evaluated the State’s 

precursor demonstration included in the 

Fairbanks Revised 189(d) Plan. The EPA 

proposes to determine that Alaska’s 

submission meets the requirements of 

40 CFR 51.1006(a)(2) and is consistent 

with the EPA guidance.59 Regarding the 

State’s analytical approach, the EPA 

proposes to find that the State used 

appropriate methods and data to 

evaluate PM2.5 formation in the 

Fairbanks PM2.5 Nonattainment Area 

from precursor emissions. Consistent 

with 40 CFR 51.1006(a)(2), Alaska’s 

submission includes a concentrationbased contribution analysis. The 

concentration-based analysis shows that 

the SO2 emissions from major stationary 

sources do not significantly contribute 

to PM2.5 formation in the Fairbanks 

PM2.5 Nonattainment Area. Specifically, 

Alaska’s analysis shows that SO2

emissions from major stationary sources 

contribute 0.21 mg/m3 of PM2.5 at the 

North Pole Hurst Road air quality 

monitor—far below the 1.5 mg/m3

threshold included in the EPA 

guidance. For the EPA’s full evaluation, 

see EPA’s Technical Support 

Document.60 Therefore, the EPA 

proposes to approve Alaska’s precursor 

demonstration submitted as part of the 

Fairbanks Revised 189(d) Plan as 

demonstrating that the contribution of 

SO2 from existing major stationary 

sources to PM2.5 levels in the Fairbanks 

PM2.5 Nonattainment Area is not 

significant in accordance with 40 CFR 

51.1006(a)(2)(i). If the EPA finalizes 

approval as proposed, Alaska will not 

be required to control SO2 emissions 

from existing major stationary sources 

in the Fairbanks PM2.5 Nonattainment 

Area, pursuant to CAA section 189 and 

40 CFR 51.1010. For purposes of the 

Fairbanks Revised 189(d) Plan, the 

PM2.5 plan precursors are: NH3 and SO2

for all sources except for major 

stationary sources. 

Consistent with its past actions, if 

finalized, the EPA’s approval of Alaska’s 


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61 Id. 

62 40 CFR 51.1010(a)(3)(i); 81 FR 58010, August 

24, 2016, at p. 58084. 

63 40 CFR 51.1010(a)(3)(ii); 81 FR 58010, August 

24, 2016, at p. 58085. 

64 81 FR 58010, August 24, 2016, at p. 58085. 

65 Id. at p. 58080 (‘‘Consistent with past policy, 

BACT determinations for PM2.5 NAAQS 

implementation are to follow the same process and 

criteria that are applied to the BACT determination 

process for the PSD program.’’). 

66 Id. at pp. 58084–85. 

67 Id. at p. 58081. 

68State Implementation Plans for Serious PM–10 

Nonattainment Areas, and Attainment Date Waivers 

for PM–10 Nonattainment Areas Generally; 

Addendum to the General Preamble for the 

Implementation of Title I of the Clean Air Act 

Amendments of 1990 (‘‘Addendum to the General 

Preamble’’), 59 FR 41998, at p. 42011 (August 16, 

1994); 81 FR 58010, August 24, 2016, at p. 58081. 

69 Id. 

70 Id. at p. 58082. 

71CAA section 189(d), 42 U.S.C. 7513a(d), and 40 

CFR 51.1010(c). 

precursor demonstration would not 

extend to nonattainment NSR 

requirements for the area. Alaska 

previously determined that it was 

appropriate to regulate NOX, SO2, VOCs, 

and NH3 as precursors to PM2.5 with 

respect to nonattainment NSR and 

submitted rule changes to that effect on 

October 25, 2018. The EPA approved 

the submitted revised program as 

meeting nonattainment NSR 

requirements triggered upon 

reclassification of the Fairbanks PM2.5

Nonattainment Area to Serious (84 FR 

45419, August 29, 2019). 

C. Control Strategy 

1. Statutory and Regulatory 

Requirements Regarding the Control 

Strategy 

CAA section 189(b) and 40 CFR 

51.1010(a) contain the control measure 

requirements for Serious areas. CAA 

section 189(d) and 40 CFR 51.1010(c) 

contain the control measure 

requirements for Serious areas that fail 

to attain. 

Pursuant to CAA section 189(b) and 

40 CFR 51.1010(a), the state must 

identify, adopt, and implement best 

available control measures, including 

best available control technologies, on 

sources of direct PM2.5 emissions and 

sources of emissions of PM2.5 plan 

precursors located in any Serious PM2.5

nonattainment area or portion thereof 

located within the state. This level of 

control stringency is commonly called 

‘‘BACM’’ and ‘‘BACT.’’ The regulation 

at 40 CFR 51.1010(a) specifies the 

requirements states must meet to 

identify potential control measures and 

in determining the measures states must 

include in the control strategy as BACM 

or BACT for the nonattainment area: 

The state must identify all sources of 

direct PM2.5 emissions and sources of 

emissions of PM2.5 precursors in the 

nonattainment area, in accordance with 

the emissions inventory requirements in 

40 CFR 51.1008(b). 

The state must identify all potential 

control measures to reduce emissions 

from all sources of direct PM2.5

emissions and sources of emissions of 

PM2.5 plan precursors in the 

nonattainment area. The state must 

survey other NAAQS nonattainment 

areas in the U.S. and identify any 

measures for direct PM2.5 and PM2.5

plan precursors not previously 

identified by the state during the 

development of the Moderate area or 

Serious area attainment plan for the 

area. 

The state must identify, adopt, and 

implement the best available control 

measures for each emission source. 

However, the state may demonstrate 

that any measure identified under 40 

CFR 51.1010(a)(2) is not technologically 

or economically feasible to implement 

in whole or in part by the end of the 

tenth calendar year following the 

effective date of designation of the area 

and may eliminate such whole or partial 

measure from further consideration. 

Overall, economic feasibility is a less 

significant factor in the BACM and 

BACT determination process.61 There 

are considerations for technological 

feasibility of a potential control 

measure, where a state may consider 

factors including but not limited to a 

source’s processes and operating 

procedures, raw materials, physical 

plant layout, and potential 

environmental impacts such as 

increased water pollution, waste 

disposal, and energy requirements.62

There are also considerations for 

economic feasibility of a potential 

control measure where a state may 

consider capital costs, operating and 

maintenance costs, and cost 

effectiveness of the measure.63 In 

assessing whether a control measure or 

technology is BACM or BACT, the state 

must consider emissions reduction 

measures with higher costs per ton 

compared to the economic feasibility 

criteria applied in their RACM or RACT 

analysis.64 With respect to determining 

BACT pursuant to CAA section 189(b), 

the EPA expects that states use the topdown BACT analysis process used in 

the Prevention of Significant 

Deterioration (PSD) Program.65

Pursuant to CAA section 189(b), a 

state with a Serious nonattainment area 

must include provisions to assure the 

implementation of BACM and BACTlevel controls on sources of direct PM2.5

and PM2.5 plan precursors no later than 

4 years after the date the area is 

classified (or reclassified) as a Serious 

area. 

In the preamble to the final PM2.5 SIP 

Requirements Rule, the EPA 

recommended the following the 5-Step 

BACM/BACT selection process that 

states should follow to satisfy the 

analytical and substantive requirements 

of 40 CFR 51.1010(a) and CAA section 

189(b): 66

Step 1: Develop a comprehensive 

inventory of sources and source 

categories of directly emitted PM2.5 and 

PM2.5 precursors. 

Step 2: Identify potential control 

measures for all such sources. 

Step 3: Determine whether an 

available control measure or technology 

is technologically feasible. 

Step 4: Determine whether an 

available control measure or technology 

is economically feasible. 

Step 5: Determine the earliest date by 

which a control measure or technology 

can be implemented in whole or in part 

in the area. 

The EPA interprets CAA section 

189(b) to require the state to determine 

what is BACM or BACT for a particular 

source or source category.67 The EPA’s 

longstanding interpretation of the CAA 

is that BACM and BACT determinations 

are to be generally independent of 

attainment for purposes of 

implementing the PM2.5 NAAQS.68 The 

EPA interprets the CAA requirement to 

impose BACM/BACT level control as 

requiring more emphasis on what 

controls are the best for the relevant 

source and whether those controls are 

feasible rather than on the attainment 

needs of the area.69 States also may not 

decline to evaluate, or to control as 

necessary, sources or source categories 

on the basis that they are de minimis.70

Subsequently, for a state with a 

Serious PM2.5 nonattainment area that 

has failed to attain by the applicable 

attainment date, the state must submit a 

revised attainment plan with a control 

strategy that demonstrates that each year 

the area will achieve at least a five 

percent reduction in emissions of direct 

PM2.5 or a five percent reduction in 

emissions of a PM2.5 plan precursor 

based on the most recent emissions 

inventory for the area; and that the area 

will attain the standard as expeditiously 

as practicable consistent with the 

attainment date requirements under 40 

CFR 51.1004(a)(3).71 The regulation at 

40 CFR 51.1010(c) specifies the 

following process the state must follow 

in determining which measures must be 

included in the control strategy: 

The state shall identify all sources of 

direct PM2.5 emissions and sources of 


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72Control measures must be incorporated by 

reference into the regulatory portion of the SIP 

(52.70(c) and (d)) with appropriate monitoring and 

reporting requirements. See CAA section 

110(a)(2)(A); 42 U.S.C. 7410(a)(2)(A); 81 FR 58010, 

August 24, 2016, at pp. 58046–47; 57 FR 13498, 

April 16, 1992, at pp.13567–68. 

73 81 FR 58010, August 24, 2016, at pp. 58046– 

47; 57 FR 13498, April 16, 1992, at pp. 13567–68; 

67 FR 22168, May 2, 2002, at p. 22170; 80 FR 

33840, June 12, 2015, at pp. 33843, 33865; Montana 

Sulphur & Chemical Co. v. EPA, 666 F.3d 1174, at 

pp. 1189–1190 (9th Cir. 2012). 

74 67 FR 22168, May 2, 2022, at p. 22170; 

Montana Sulphur & Chemical Co. v. EPA, 666 F.3d 

1174, at pp. 1189–1190 (9th Cir. 2012). 

75 88 FR 84626, December 5, 2023, at p. 84674. 

76 88 FR 84626, December 5, 2023, at pp. 84699, 

84673–84675. 

77 Id. 

78 Id. 

emissions of PM2.5 precursors in the 

nonattainment area in accordance with 

the emissions inventory requirements in 

40 CFR 51.1008(b). 

The state shall identify all potential 

control measures to reduce emissions 

from all sources of direct PM2.5

emissions and sources of emissions of 

PM2.5 plan precursors in the 

nonattainment area. For the sources and 

source categories represented in the 

emissions inventory for the 

nonattainment area, the state shall 

identify the most stringent measures 

(MSM) for reducing direct PM2.5 and 

PM2.5 plan precursors adopted into any 

SIP or used in practice to control 

emissions in any state, as applicable. 

The state shall also reconsider and 

reassess any measures previously 

rejected by the state during the 

development of any Moderate area or 

Serious area attainment plan control 

strategy for the area. Similar to the 

requirements for Serious area plans, the 

state may make a demonstration for a 

189(d) plan that a measure is not 

technologically or economically feasible 

to implement in whole or in part within 

5 years or such longer period as the EPA 

may determine is appropriate after the 

EPA’s determination that the area failed 

to attain by the Serious area attainment 

date and may eliminate such whole or 

partial measure from further 

consideration. There are considerations 

for technological feasibility of a 

potential control measure, as described 

under 40 CFR 51.1010(c)(3)(i), where a 

state may consider factors including but 

not limited to a source’s processes and 

operating procedures, raw materials, 

physical plant layout, and potential 

environmental impacts such as 

increased water pollution, waste 

disposal, and energy requirements. 

There are also considerations for 

economic feasibility of a potential 

control measure, under 40 CFR 

51.1010(c)(3)(ii), where a state may 

consider capital costs, operating and 

maintenance costs, and cost 

effectiveness of the measure. Unless the 

state has demonstrated that the measure 

is not technologically or economically 

feasible, the state shall adopt and 

implement all potential control 

measures identified. 

Finally, control measures adopted as 

part of the state’s control strategy must 

be permanent, enforceable as a practical 

matter, and quantifiable.72 In order to be 

enforceable as a practical matter, the 

state must adopt into the SIP not only 

the control measure or emissions limit 

itself but also appropriate monitoring, 

recordkeeping, and reporting 

requirements to ensure compliance with 

the control measure.73 Without 

appropriate monitoring, recordkeeping, 

and reporting requirements, violations 

of the control measure could go 

undetected.74

2. Summary of the EPA’s Prior 

Rulemaking Regarding the Control 

Strategy 

On December 5, 2023, the EPA 

finalized an approval in part and 

disapproval in part of the BACM 

requirements for the Fairbanks PM2.5

Nonattainment Area. The EPA’s action 

for each emissions source category is 

described in the following paragraphs. 

a. Alaska’s Identification and Adoption 

of BACM for Home Heating and Other 

Area Sources 

i. Solid Fuel-Burning 

The EPA approved in part and 

disapproved in part Alaska’s analysis 

and adoption of control measures for 

this source category as meeting the 

BACM requirements for PM2.5 and SO2

emissions.75 The EPA approved 

Alaska’s analysis that found no NH3- 

specific emissions controls for this 

source category. The EPA also 

previously approved as SIP 

strengthening and federally enforceable 

many of the control measures submitted 

as part of the Fairbanks Serious Plan 

and prior SIP submissions in 2018 as 

part of a separate action (86 FR 52997, 

September 24, 2021). 

Alaska identified a number of solid 

fuel-burning control measures that have 

been adopted by other states and local 

authorities to identify the full range of 

potential BACM/BACT measures for 

this source category. This analysis took 

into account technical and economic 

feasibility and other considerations 

included in the PM2.5 SIP Requirements 

Rule. 

Alaska’s two-stage Solid Fuel-Burning 

Appliance Curtailment Program, 

included in the Fairbanks Emergency 

Episode Plan, adopts air quality 

thresholds that are at least as stringent 

as comparable curtailment programs in 

Idaho, Utah, and California. Alaska 

accounted for the differences in natural 

gas availability, seasonal climate 

conditions, and wood stove change-out 

incentives in establishing the two-stage 

thresholds at 20 mg/m3 (Stage 1) and 30 

mg/m3 (Stage 2), respectively. Alaska 

also had an advisory level set at 15 mg/ 

m3 as part of the curtailment program. 

Alaska placed further limitations on the 

‘‘No Other Adequate Source of Heat’’ 

(NOASH) waiver (available to 

households as a temporary waiver from 

certain curtailment requirements), 

limiting applicability to those that have 

economic needs based on objective 

criteria and limiting the number of years 

NOASH waivers are available. 

Therefore, the EPA approved the Solid 

Fuel-Burning Appliance Curtailment 

Program and associated updates to the 

NOASH waivers and temporary 

exemption as BACM for the solid-fuel 

burning source category (i.e., Alaska 

state regulations 18 AAC 50.075 (e)(3), 

(f)(2)) for PM2.5 and SO2 emissions.76

Alaska identified and evaluated as 

BACM the heating device performance 

standards adopted previously by 

Missoula County, Montana. Alaska 

adopted a regulation modeled after the 

rule in Missoula County. Under 18 AAC 

50.077(c), Alaska’s regulations require 

that wood stoves meet emissions 

standards that are more stringent than 

the EPA’s New Source Performance 

Standards (NSPS) requirement for 

residential wood heaters at 40 CFR part 

60 and also include one-hour testing 

requirements to ensure only the lowestemitting wood stoves are allowed to be 

sold and installed in the nonattainment 

area. The EPA approved these measures 

as BACM for the solid-fuel burning 

source category (i.e., 18 AAC 50.077 (a– 

j)) for PM2.5 and SO2 emissions.77

Alaska’s regulation 18 AAC 50.075(f), 

applicable to the Fairbanks PM2.5

Nonattainment Area, prohibits the 

operation of a solid fuel-fired heating 

device emissions when visible 

emissions exceed 20 percent opacity for 

more than six minutes in any one hour, 

except during the first 15 minutes after 

initial firing of the device, when the 

opacity limit must be less than 50 

percent. The rule also prohibits visible 

emissions from crossing property lines. 

These opacity limits provide a visual 

indicator for the proper operation of a 

solid-fuel heating device. The EPA 

approved this measure as BACM.78

The EPA approved as BACM the 

additional removal or render inoperable 


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79 Id. 

80 Id. 

81 88 FR 84626, December 5, 2023, at pp. 84670, 

84675–76. 

82 88 FR 84626, December 5, 2023, at p. 84674– 

75. 

83 Id. 

84 88 FR 84626, December 5, 2023, at p. 84676; 

See also 81 FR 58010, August 24, 2016, at p. 58047. 

85 88 FR 84626, December 5, 2023, at pp. 84641, 

84676; See also 81 FR 58010, August 24, 2016, at 

p. p. 58085. 

86 88 FR 84626, December 5, 2023, at p 84675– 

76. 

87 Id. 

88 Id. 

89 88 FR 84626, December 5, 2023, at pp. 84670– 

71, 84675–76. 

90 Id. 

restrictions placed on non-certified EPA 

wood stoves, non-pellet outdoor 

hydronic heaters, coal-fired heating 

devices, and EPA-certified wood stoves 

greater than 25 years-old meet BACM 

requirements for PM2.5 and SO2

emissions.79 These devices are to be 

removed or rendered inoperable by 

December 31, 2024, or if a building or 

residence with such a device is sold 

prior to that date (or if a wood-fired 

heating device is 25 years old prior to 

that date). These include Alaska state 

regulations 18 AAC 50.077 (l–m). The 

EPA approved the other solid-fuel 

burning regulations adopted by Alaska, 

including device registration under 18 

AAC 50.077(h) and dry wood 

requirements for wood sellers 18 AAC 

50.076, which are at least as stringent as 

similar regulations adopted by other 

states and local authorities, and 

therefore represent BACM for PM2.5 and 

SO2 emissions for the solid-fuel burning 

source category.80 These include Alaska 

state regulations 18 AAC 50.076 (d–e), 

(g), (j–l). 

However, the EPA partially 

disapproved as BACM Alaska’s 

measures regarding dry wood seller 

requirements and coal-fired heating 

devices.81 The EPA recommended 

Alaska revise 18 AAC 50.076(k)(3) to 

require a specific frequency wood 

sellers are required to measure the 

moisture content of the seller’s wood 

stock. Likewise, the EPA also 

recommended Alaska revise the 

regulations at 18 AAC 50.079(d), (e) and 

(f) to remove (or revise to BACM and 

BACT-level stringency) the testing 

exemption in (d), remove or properly 

bound the waiver provision in (e), and 

add requirements to verify compliance 

with the requirement for the owner and 

operator to render the device 

inoperative. 

ii. Residential and Commercial Fuel Oil 

Combustion 

Alaska adopted the regulation at 18 

AAC 50.078(b) that imposed a limit of 

1,000 parts per million sulfur (diesel no. 

1) for residential and commercial 

heating. This was a switch from diesel 

no. 2 (approximately 2,000 parts per 

million sulfur) to diesel no. 1. Alaska 

also evaluated the potential for adopting 

ULSD for fuel oil combustion, but the 

State determined that this measure is 

economically infeasible. The EPA 

approved 18 AAC 50.078(b) as meeting 

the SO2 BACM and BACT requirements 

for the space heating area source 

category.82

iii. Small Commercial Area Sources 

The EPA approved Alaska’s 

determination that there were no 

incinerators in the nonattainment area. 

Therefore, Alaska need not identify, 

adopt, or implement controls for the 

incinerator source category. The EPA 

also approved Alaska’s BACM 

infeasibility demonstrations for add-on 

control for charbroilers and restrictions 

on used oil burners. By extension, the 

EPA approved 18 AAC 50.055 as 

BACM/BACT for the charbroiler source 

category.83

However, the EPA disapproved 

Alaska’s BACM requirements for coffee 

roasters. The EPA cited a number of 

deficiencies with Alaska’s adopted 

control measure for coffee roasters at 18 

AAC 50.078(d).84

iv. Weatherization and Energy 

Efficiency 

The EPA disapproved Alaska’s BACM 

analysis with respect to potential energy 

efficiency and weatherization measures. 

The State provided a number of reasons 

for declining to adopt and implement 

any such measures, each of which the 

EPA rejected as bases to not adopt 

weatherization and energy efficiency 

measures.85

v. Emissions From Mobile Sources 

The EPA approved Alaska’s rejection 

of the CARB vehicle standards as 

economically infeasible. The EPA 

likewise finalized approval of Alaska’s 

rejection of school bus retrofits, road 

paving, and controls on road sanding 

and salting as technologically infeasible. 

The EPA approved Alaska’s rejection of 

a motor vehicle inspection and 

maintenance (I/M) program. The EPA 

approved Alaska’s determination that 

no NH3-specific emissions controls exist 

for this source category.86

The EPA approved Alaska’s rejection 

of other transportation measures as 

either technologically infeasible (HOV 

lanes) or economically infeasible (traffic 

flow improvements, diesel retrofit 

projects, and ridesharing programs).87

However, the EPA approved in part 

and disapproved in part Alaska’s 

rejection of vehicle idling restrictions 

and other transportation measures.88

Specifically, the EPA approved Alaska’s 

rejection of vehicle idling restrictions 

for heavy-duty diesel vehicles as 

economically infeasible. However, the 

EPA disapproved Alaska’s rejection of 

vehicle idling restrictions for light-duty 

vehicles at schools and commercial 

establishments. The EPA determined 

that Alaska had not demonstrated that 

vehicle anti-idling restrictions for lightduty passenger vehicles are infeasible. 

b. Alaska’s Identification and Adoption 

of BACT for Major Stationary Sources 

In its December 5, 2023, action, the 

EPA partially approved and partially 

disapproved the Fairbanks Serious Plan 

as meeting the BACM and BACT 

requirements for major stationary 

sources. 

i. Chena Power Plant 

The EPA partially approved and 

partially disapproved Alaska’s BACM/ 

BACT evaluation for the Chena Power 

Plant. The EPA partially disapproved 

the BACT determination because Alaska 

did not identify, adopt, and implement 

BACT for PM2.5 and SO2. The EPA 

approved Alaska’s BACT analysis for 

NH3 emissions controls for the Chena 

Power Plant.89

ii. Doyon-Fort Wainwright Central 

Heating and Power Plant 

The EPA partially approved and 

partially disapproved Alaska’s BACM/ 

BACT determinations for PM2.5 controls 

for each of the emission sources at 

Doyon-Fort Wainwright Central Heating 

and Power Plant. The EPA partially 

approved the BACT determinations 

because Alaska’s BACT findings for 

PM2.5 (embodied in State Air Quality 

Control Plan, Vol. II, section III.D.7.7, 

Tables 7.7–11 and 7.7–13 and section 

III.D.7.7.8.3.4) were consistent with 

CAA section 189(b) and 40 CFR 

51.1010(a). The EPA partially 

disapproved the BACT determinations 

because the Fairbanks Serious Plan and 

initial Fairbanks 189(d) Plan lacked 

provisions necessary to ensure the 

BACT determinations for PM2.5 are 

enforceable as a practical matter as 

required by CAA sections 110(a)(2)(A) 

and 172(c)(7).90

On September 25, 2023, Alaska 

withdrew its SO2 BACT determinations 

for Doyon-Fort Wainwright Central 

Heating and Power Plant. Therefore, the 

EPA finalized disapproval of Alaska’s 

SO2 BACT determinations because the 


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91 Id. 

92 Id. at p. 84657 

93 Id. at pp. 84670–71, 84675–76. 

94 Id. 

95 Id. 

96 Id. 

97 Id. 

98State Air Quality Control Plan, Vol. II, section 

III.D.7.7.13. 

Fairbanks Serious Plan and initial 

Fairbanks 189(d) Plan did not identify, 

adopt, and implement BACT for SO2 at 

the Doyon-Fort Wainwright Central 

Heating and Power Plant. The EPA 

approved Alaska’s analysis that found 

no NH3-specific emissions controls for 

the sources at this facility.91

iii. University of Alaska Fairbanks 

Campus Power Plant 

The EPA disapproved Alaska’s 

BACM/BACT determination for PM2.5

controls for the Small Diesel-Fired 

Engines (EU IDs 23, 26, and 27). The 

EPA partially approved and partially 

disapproved the Alaska’s BACT 

determinations for PM2.5 controls for the 

remaining emission units. The EPA 

partially approved the PM2.5 BACT 

determinations because Alaska’s BACT 

determinations embodied in State Air 

Quality Control Plan, Vol. II, section 

III.D.7.7, Table 7.7–16 and section 

III.D.7.7.8.6 were consistent with CAA 

section 189(b) and 40 CFR 51.1010(a). 

The EPA partially disapproved Alaska’s 

BACT determinations because the 

Fairbanks Serious Plan and initial 

Fairbanks 189(d) Plan lacked provisions 

necessary to ensure the BACT 

determinations are enforceable as a 

practical matter as required by CAA 

sections 110(a)(2)(A) and 172(c)(7).92

On September 25, 2023, Alaska 

withdrew its SO2 BACT determinations 

for the Fairbanks Campus Power Plant. 

Therefore, the EPA disapproved 

Alaska’s SO2 BACT determinations 

because the Fairbanks Serious Plan and 

initial Fairbanks 189(d) Plan did not 

identify, adopt, and implement BACT 

for SO2 at the Fairbanks Campus Power 

Plant. The EPA approved Alaska’s 

analysis that found no NH3-specific 

emissions controls for the sources at this 

facility.93

iv. Zehnder Power Plant 

The EPA partially approved and 

partially disapproved Alaska’s BACM/ 

BACT provisions for PM2.5 controls for 

all emission units at the Zehnder Power 

Plant. The EPA partially approved the 

PM2.5 BACT determination because 

Alaska’s BACT determinations 

embodied in the State Air Quality 

Control Plan, Vol. II, section III.D.7.7, 

Table 7.7–14 and Appendix III.D.7.7.8.4 

are consistent with CAA section 189(b) 

and 40 CFR 51.1010(a). The EPA 

partially disapproved Alaska’s PM2.5

BACT determinations because the 

Fairbanks Serious Plan and initial 

Fairbanks 189(d) Plan lacked provisions 

necessary to ensure the PM2.5 BACT 

determinations are enforceable as a 

practical matter as required by CAA 

sections 110(a)(2)(A) and 172(c)(7).94

On September 25, 2023, Alaska 

withdrew its SO2 BACT determinations 

for the Zehnder Power Plant. Therefore, 

the EPA partially disapproved the SO2

BACT determinations because Fairbanks 

Serious Plan and initial Fairbanks 

189(d) Plan did not identify, adopt, and 

implement BACT for SO2 at the Zehnder 

Power Plant. The EPA approved 

Alaska’s analysis that found no NH3- 

specific emissions controls for the 

sources at this facility.95

v. North Pole Power Plant 

The EPA partially approved and 

partially disapproved Alaska’s BACM/ 

BACT provisions for PM2.5 controls for 

all emission units at the North Pole 

Power Plant. The EPA partially 

approved Alaska’s PM2.5 BACT 

determinations because these findings 

embodied in State Air Quality Control 

Plan, Vol. II, section III.D.7.7, Table 7.7– 

14 and Appendix III.D.7.7.8.5 are 

consistent with CAA section 189(b) and 

40 CFR 51.1010(a). The EPA partially 

disapproved Alaska’s PM2.5 BACT 

determinations because the Fairbanks 

Serious Plan and initial Fairbanks 

189(d) Plan lacked provisions necessary 

to ensure the BACT determinations are 

enforceable as a practical matter as 

required by CAA sections 110(a)(2)(A) 

and 172(c)(7).96

On September 25, 2023, Alaska 

withdrew its SO2 BACT determinations 

for the North Pole Power Plant. 

Therefore, the EPA partially 

disapproved Alaska’s SO2 BACT 

determinations because the Fairbanks 

Serious Plan and initial Fairbanks 

189(d) Plan did not identify, adopt, and 

implement BACT for SO2 at the North 

Pole Power Plant. The EPA approved 

Alaska’s analysis that found no NH3- 

specific emissions controls for the 

sources at this facility. 

c. NH3 Emissions Controls 

With respect to NH3 controls, for 

residential and commercial area 

sources, the EPA approved certain 

measures as meeting the BACM/BACT 

requirement for NH3 emissions. In other 

cases, the EPA approved Alaska’s 

BACM/BACT analysis that concluded 

there are no NH3-specific controls for 

the emission source categories 

contributing to PM2.5 formation in the 

Fairbanks PM2.5 Nonattainment Area, 

but that there are likely to be NH3

emissions co-benefits of measures 

designed to reduce emissions of direct 

PM2.5.97

3. Summary of the State’s Submission 

and the EPA’s Evaluation and Proposed 

Action Regarding the Control Strategy 

a. Updates to the Identification and 

Adoption of BACM 

Below is a summary of the regulations 

and SIP revisions adopted as part of the 

Fairbanks Revised 189(d) Plan, 

organized by source category, 

responding to EPA’s December 5, 2023, 

disapproval.98

i. Solid-Fuel Burning 

Alaska revised the dry wood seller 

measure, adopted as regulation 18 AAC 

50.076(k)(3), by setting a frequency at 

monthly intervals to measure the 

moisture content. Alaska also revised 

regulation 18 AAC 50.076(k)(1) by 

improving the labeling to indicate ‘‘dry 

wood.’’ 

Regarding the EPA’s disapproval of 

coal-fired heating device requirements, 

Alaska revised 18 AAC 50.079 by 

lowering the emissions threshold to test 

out of the mandatory removal 

requirements in 18 AAC 50.079(d) from 

18 grams per hour to 0.10 pounds per 

million British thermal units (Btu) 

which is equivalent to the pellet 

hydronic heater limit in 18 AAC 50.077. 

Alaska amended 18 AAC 50.079(d) to 

require a testing protocol be approved 

by the department prior to any test 

attempting to exempt a coal device from 

the mandatory removal requirement. 

Alaska revised 18 AAC 50.079(e) limit 

the duration of the waiver to one 

calendar year. 

The EPA previously approved 18 

AAC 50.079(f), which requires the 

owner of a coal-fired heating device to 

render it inoperable not later than 

December 31, 2024. As a consequence of 

Alaska’s revisions to 18 AAC 50.079(f), 

the latest an individual with a coal-fired 

heating device could remove that device 

is December 31, 2025—provided the 

individual meets the eligibility 

requirements in 18 AAC 50.079(e). 

Alaska stated that 18 AAC 50.079(f) is 

revised for clarity by adding section (3), 

which requires coal-fired heating 

devices to be rendered inoperable after 

the expiration of a waiver granted under 

subsection (e) of 18 AAC 50.079. Alaska 

stated that newly adopted section 18 

AAC 50.079(h) requires documentation 

on the removal and rendering of the 

device inoperable and submitting an 

affidavit that the coal stove will not be 


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99 88 FR 84626, December 5, 2023, at pp. 84669, 

84674. 

100 82 FR 42457, September 8, 2017; State Air 

Quality Control Plan, Vol. III, Appendix III.D.5.7, 

adopted December 24, 2014, at p. 43; State Air 

Quality Control Plan, Vol. III, Appendix III.D.5.12, 

adopted December 24, 2014, at p. 43. 

101There are nearly 10,000 plug-ins available in 

the nonattainment area. See State Air Quality 

Control Plan, Appendix III.D.7.7 (adopted 

November 19, 2019), at p. 17. 

102 88 FR 84626, December 5, 2023, at pp. 84649, 

84652 (determining that anti-idling restrictions on 

heavy-duty vehicles had a cost effectiveness of over 

$400,000 per ton of SO2 reduced). 

103State Air Quality Control Plan Vol. II, 

Appendix III.D.7.7 (adopted November 5, 2024). 

reinstalled in the Fairbanks PM2.5

Nonattainment Area. 

Based on these updates, the EPA 

proposes to approve the submitted 

revisions to 18 AAC 50.076 and 18 AAC 

50.079 as meeting the requirements of 

CAA sections 110(a)(2)(A), 172(c)(7), 

and 189(b) and 40 CFR 51.1010(a). 

Accordingly, the EPA proposes to 

determine that the Fairbanks Revised 

189(d) Plan rectifies the disapproved 

portions of the Fairbanks Serious Plan 

and initial Fairbanks 189(d) Plan for the 

solid fuel-burning source category. 

ii. Residential and Commercial Fuel Oil 

Combustion 

In the EPA’s December 5, 2023, rule, 

the EPA approved as BACM Alaska’s 

regulation under 18 AAC 50.078(b) that 

imposes a limit of 1,000 parts per 

million sulfur content in fuel limit 

(diesel no. 1) for residential and 

commercial heating.99 This was a switch 

from diesel no. 2 (approximately 2,000 

parts per million sulfur content in fuel 

limit) to diesel no. 1. The EPA agreed 

with Alaska’s demonstration that further 

strengthening this requirement to 15 

parts per million sulfur (i.e., Ultra-low 

sulfur diesel) was economically 

infeasible. 

iii. Small Commercial Area Sources 

Alaska revised its regulations for 

coffee roasters, under 18 AAC 50.078(d). 

These updated regulations clarify the 

specific emission limit required for this 

source category and ensures the limit is 

enforceable as a practical matter. The 

EPA proposes to approve the submitted 

revisions to 18 AAC 50.078(d) as 

meeting the requirements of CAA 

section 110(a)(2), 172(c)(7), and 189(b) 

and 40 CFR 51.1010(a) for this source 

category. Accordingly, the EPA 

proposes to determine that the 

Fairbanks Revised 189(d) Plan rectifies 

the disapproved portions of the 

Fairbanks Serious Plan and initial 

Fairbanks 189(d) Plan for coffee 

roasters. 

iv. Energy Efficiency and 

Weatherization 

To address the EPA’s disapproval, 

Alaska reviewed weatherization and 

energy efficiency measures adopted by 

other jurisdictions. Based on this 

review, Alaska adopted a weatherization 

and energy efficiency measure at 18 

AAC 50.081. The measure mandates 

that a building owner have an energy 

rating completed on the building before 

listing it for sale. The rule requires that 

the seller provide the energy rating 

report to the buyer. Alaska also 

committed to a robust advertising and 

education program that includes best 

practices to improve efficiency in an 

arctic environment and available 

economic and practical mechanisms 

that can assist homeowners in 

improving both efficiency and 

regulatory compliance. Alaska asserted 

that these components will improve the 

compliance rate for other control 

measures, including the solid fuel-fired 

heating device curtailment program and 

the requirement to remove older, 

uncertified heating appliances. Alaska 

noted that any improvements identified 

by the energy rater will be voluntary. 

Alaska evaluated adopting building 

energy efficiency codes or mandatory 

weatherization requirements and 

dismissed them as technologically 

infeasible. According to Alaska, there is 

a lack of technical expertise and 

resources to implement (lack of energy 

auditors and training resources), 

enforce, and ensure code compliance. 

Alaska further contended that the 

earliest date Alaska can implement 

building codes exceeded not only the 

statutory requirement for the 

implementation of BACM by December 

31, 2024, but also beyond the 2027 

attainment date identified in the 

Fairbanks Revised 189(d) Plan. 

The EPA proposes to approve the 

submitted revisions to 18 AAC 50.081 as 

meeting the requirements of CAA 

sections 110(a)(2), 172(c)(7), and 189(b) 

and 40 CFR 51.1010(a) with respect to 

weatherization and energy efficiency. 

Accordingly, the EPA proposes to 

determine that the Fairbanks Revised 

189(d) Plan rectifies the disapproved 

portions of the Fairbanks Serious Plan 

and initial Fairbanks 189(d) Plan for 

weatherization and energy efficiency. 

v. Emissions From Mobile Sources 

The EPA previously approved as part 

of Fairbanks Moderate Plan, a 

requirement that businesses with 275 or 

more parking spaces provide power to 

electrical outlets at temperatures of 20 

degrees Fahrenheit or lower for engine 

block heaters.100 In addition, Alaska 

continues to install new plug-ins 

throughout the Fairbanks PM2.5

Nonattainment Area.101

As part of the Fairbanks Revised 

189(d) Plan, Alaska re-evaluated antiidling for light-duty vehicles as a 

potential control measure. Alaska 

provided additional analysis 

demonstrating that such a measure is 

technologically and economically 

infeasible in the Fairbanks PM2.5

Nonattainment Area. In particular, 

Alaska noted that other jurisdictions 

that implement this measure include a 

temperature threshold, below which 

restrictions do not apply. These 

temperature cut offs range from 40 

degrees Fahrenheit to 10 degrees 

Fahrenheit. These thresholds are 

intended to protect human health and 

safety. 

Accordingly, Alaska evaluated 

implementing idling restrictions during 

the winter months of October through 

March at temperatures above 21 degrees 

Fahrenheit. Given that episodic 

emissions contributing to PM2.5

concentrations occur at sub-zero 

temperatures, Alaska’s evaluation 

indicates that the measure would not 

achieve any emissions reductions. 

The EPA notes that in order to 

achieve emissions reductions in the 

extreme Fairbanks environment, Alaska 

would have to prohibit idling regardless 

of ambient temperature, which presents 

unacceptable risks to human health. In 

light of these concerns, rather than 

regulate the vehicle users, Alaska 

requires owners of parking areas to 

provide electricity for engine-block 

heaters. Alaska and the EPA have 

previously determined that expanding 

plug-in availability is economically 

infeasible.102 Therefore, the EPA 

proposes to approve Alaska’s current 

plug-in program as meeting BACM and 

BACT requirements for light-duty 

vehicles. 

Accordingly, the EPA proposes to 

determine that Alaska has rectified the 

EPA’s December 5, 2023, disapproval of 

the Fairbanks Serious Plan and initial 

Fairbanks 189(d) Plan with respect to 

control strategy requirements for mobile 

sources. 

b. Alaska’s Identification and Adoption 

of BACT for Major Stationary Sources 

Alaska submitted revisions to its 

BACM/BACT determinations for the 

five major stationary sources in the 

Fairbanks PM2.5 Nonattainment Area, as 

described in the following 

paragraphs.103 Alaska also submitted 

permits for each of the five major 


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104See State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–164. Note, Alaska’s prior SIP 

submissions only evaluated BACT for the coal-fired 

boilers. 

105See State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–187. 

106See Hedgpeth and Sorrels. (August 24, 2022). 

Review of Best Available Control Technology 

analyses submitted for the Aurora Energy, LLC 

Chena Power Plant as part of the Fairbanks PM2.5

Nonattainment SIP. U.S. Environmental Protection 

Agency, Region 10, Laboratory Services and 

Applied Science Division, EPA–R10–OAR–2022– 

0115. 

107See State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–173. 

108See section III.A of this preamble for the 

specific permit conditions proposed for approval. 

109Alaska evaluated potential NOX controls for 

each emission unit, but because Alaska determined 

and the EPA approved that NOX emissions are not 

significant for PM2.5 formation in the Fairbanks 

PM2.5 Nonattainment Area, Alaska does not plan to 

require implementation of BACT for NOX. See 88 

FR 84626, December 5, 2023. Thus, EPA is not 

discussing Alaska’s BACT analysis for NOX here. 

110See State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–202. 

111See State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–248. 

112See Hedgpeth, Z. (August 24, 2022). Review of 

Best Available Control Technology analyses 

submitted for Fort Wainwright-US Army Garrison 

Alaska (FWA) and Doyon Utilities, LLC (DU) as part 

of the Fairbanks PM2.5 Nonattainment SIP. U.S. 

Environmental Protection Agency, Region 10, 

Laboratory Services and Applied Science Division, 

EPA–R10–OAR–2022–0115. 

113See State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–217; State Air Quality Control 

Plan, Vol. III, Appendix III.D.7.7–225. 

stationary sources that adopt and 

implement BACT for direct PM2.5. 

i. Chena Power Plant 

Chena Power Plant is an existing 

stationary source owned and operated 

by Aurora Energy, LLC, which consists 

of four existing coal-fired boilers: three 

76 million British Thermal Units 

(MMBtu) per hour overfeed traveling 

grate stoker type boilers and one 269 

MMBtu per hour spreader-stoker type 

boiler that burn coal to produce steam 

for heating and power (497 MMBtu per 

hour combined). The source also 

includes a coal preparation plant, coal 

stockpile, ash vacuum pump exhaust, 

and truck bay ash loadout. 

Alaska revised its State Air Quality 

Control Plan to include its BACT 

determinations for PM2.5 and SO2 for 

each of the emission units at the Chena 

Power Plant.104 We note that Alaska 

removed its BACT evaluation and 

determinations for NOX because the 

EPA approved a comprehensive NOX

precursor demonstration. Alaska also 

submitted conditions from Air Quality 

Control Minor Permit AQ0315MSS02 

Revision 1 for the Aurora Energy, LLC— 

Chena Power Plant (Aurora Permit). The 

Aurora Permit conditions include 

enforceable PM2.5 BACT emissions 

limitations for the emission units at the 

Chena Power Plant comprised of 

numerical emissions limits and work 

practice standards and associated 

monitoring, recordkeeping and 

reporting requirements. The permits are 

included in the docket for this action.105

The EPA previously reviewed 

Alaska’s BACM/BACT evaluation for 

the Chena Power Plant.106 Alaska has 

since clarified that PM2.5 BACT for the 

coal-fired boilers is operating and 

maintaining fabric filters (full steam 

baghouse) during operation.107 Thus, in 

this action, the EPA is proposing to 

approve Alaska’s PM2.5 BACT 

determinations for the Chena Power 

Plant, the submitted revisions to State 

Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7, related to direct 

PM2.5 emissions and the submitted 

Aurora Permit conditions108 as 

satisfying CAA section 189(b) and 40 

CFR 51.1010. 

The EPA is not proposing to take 

action on Alaska’s SO2 BACT 

determinations in State Air Quality 

Control Plan, Vol. III, Appendix 

III.D.7.7, at this time. As discussed in 

the preceding paragraphs, the EPA is 

proposing to approve Alaska’s SO2

precursor demonstration for major 

stationary sources. If approved, Alaska 

will not be required to identify, adopt, 

or implement SO2 BACT for the Chena 

Power Plant. If the EPA does not finalize 

approval of the SO2 precursor 

demonstration, then the EPA will 

propose action on Alaska’s SO2 BACT 

determinations in a separate, future 

action. 

ii. Doyon-Fort Wainwright Central 

Heating and Power Plant 

Fort Wainwright is an existing U.S. 

Army installation. Emission units 

located within the military installation 

include units such as boilers and 

generators that are owned and operated 

by the U.S. Army Garrison Alaska 

(referred to as FWA). The Central 

Heating and Power Plant (CHPP), also 

located within the installation footprint, 

is owned and operated by Doyon 

Utilities, LLC (DU), the regional Alaska 

Native corporation for Interior Alaska. 

The two entities, DU and FWA, 

comprise a single stationary source 

operating under two permits. 

The CHPP is comprised of six 

spreader-stoker type coal-fired boilers, 

each rated at 230 MMBtu per hour, that 

burn coal to produce steam for 

stationary source-wide heating and 

power. In addition to the CHPP, the 

source contains emission units 

comprised of small and large emergency 

engines, fire pumps, and generators, 

diesel-fired boilers, and material 

handling equipment. Alaska’s BACM/ 

BACT analysis in the Fairbanks Serious 

Plan for the stationary source evaluated 

potential controls to reduce NOX, PM2.5, 

and SO2 emissions from each of these 

emissions units at the stationary 

source.109

As part of the Fairbanks Revised 

189(d) Plan, Alaska revised its Air 

Quality Control Plan sections related to 

the Doyon-Fort Wainwright CHPP to 

reflect new engines powering lift pumps 

and generators, correct typographical 

errors, improve clarity, and to include 

updated SO2 BACT determinations.110

With respect to the new engines, all are 

EPA-certified engines ranging in size 

from 74 horsepower to 324 horsepower. 

Alaska updated its PM2.5 BACT 

determinations for these new engines. 

Alaska removed its BACT evaluation 

and determinations for NOX because the 

EPA approved a comprehensive NOX

precursor demonstration. 

Alaska also submitted conditions 

from two Air Quality Control Minor 

Permits: AQ0236MSS03 Revision 2 

(U.S. Army Garrison—USAG Alaska 

Fort Wainwright) and AQ1121MSS04 

Revision 1 (Doyon Utilities, LLC—Fort 

Wainwright) (collectively referred to as 

the Fort Wainwright Permits). The Fort 

Wainwright Permits include enforceable 

PM2.5 BACT emissions limitations for 

the emission units at Fort Wainwright 

comprised of numerical emissions 

limits and work practice standards and 

associated monitoring, recordkeeping 

and reporting requirements. The permits 

are included in the docket for this 

action.111

The EPA previously reviewed 

Alaska’s BACM/BACT evaluation for 

the Doyon-Fort Wainwright Central 

Heating and Power Plant.112 In addition 

to the submitted conditions discussed in 

this section x.x.ii of this preamble, 

Alaska’s updated BACT determination 

clarified the maintenance and testing 

requirements for the diesel-fired boilers 

and added enclosed conveying system 

requirements.113 The EPA previously 

approved Alaska’s BACT 

determinations for older pump engines 

and generator engines. Alaska updated 

its BACT determinations and associated 

permit limits to reflect grams per hour 

emission limits appropriate to the size 

and model year of the engine. Alaska 

also imposed limits on the hours of 

operations of these engines. Thus, in 

this action, the EPA is proposing to 

approve Alaska’s updated PM2.5 BACT 

determinations for the emissions units 


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114 Industrial coal-fired boilers; diesel-fired 

boilers; diesel-fired engines, fire pumps, and 

generators; and material handling equipment. 

115The EPA is not proposing to approve the NOX

related emissions limits as meeting BACT for NOX. 

For some emission units, Alaska imposed NOX

emissions limits as surrogates for direct PM2.5

emissions. 

116See section III.A of this preamble for the 

specific permit conditions proposed to be approved. 

117See State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–356. 

118Alaska noted that it previously selected a 

0.012 lb/MMBtu limit erroneously. This limit is 

associated with industrial boilers while the boilers 

at the Fairbanks Campus Power Plant are 

commercial boilers. 

119State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–369. 

120 In comments, the University of Alaska 

Fairbanks clarified that EU 23 has been 

permanently removed from service and are no 

longer permitted EUs at the facility. See Comments 

on Proposed Rule—Air Plan Partial Approval and 

Partial Disapproval; AK, Fairbanks North Star 

Borough; 2006 24-Hour PM2.5 Serious Area and 

189(d) Plan, at p. 9, Docket ID No. EPA–R10–OAR– 

2022–0115. 

121State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–372. 

122See Hedgpeth and Sorrels. (August 24, 2022). 

Review of Best Available Control Technology 

analyses submitted for the University of Alaska, 

Fairbanks as part of the Fairbanks PM2.5

Nonattainment SIP, p.15. U.S. Environmental 

Protection Agency, Region 10, Laboratory Services 

and Applied Science Division, EPA–R10–OAR– 

2022–0115. 

123State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–374. 

124 88 FR 84626, December 5, 2023. 

125See State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–414. 

126See Hedgpeth and Sorrels. (August 24, 2022). 

Review of Best Available Control Technology 

analyses submitted for the University of Alaska, 

Fairbanks as part of the Fairbanks PM2.5

Nonattainment SIP. U.S. Environmental Protection 

Agency, Region 10, Laboratory Services and 

Applied Science Division, EPA–R10–OAR–2022– 

0115. 

127The EPA is not proposing to approve the NOX

related emissions limits as meeting BACT for NOX. 

For some emission units, Alaska imposed NOX

emissions limits as surrogates for direct PM2.5

emissions. 

at Doyon-Fort Wainwright CHPP,114 the 

submitted revisions to State Air Quality 

Control Plan, Vol. III, Appendix III.D.7.7 

related to direct PM2.5 emissions from 

the Doyon-Fort Wainwright CHPP,115

and the submitted conditions from the 

Fort Wainwright Permits116 as satisfying 

CAA section 189(b) and 40 CFR 

51.1010. 

The EPA is not proposing to take 

action on Alaska’s SO2 BACT 

determinations in State Air Quality 

Control Plan, Vol. III, Appendix III.D.7.7 

at this time for the same reasons 

discussed in the preceding paragraphs 

regarding the Chena Power Plant. If the 

EPA does not finalize approval of the 

SO2 precursor demonstration, then the 

EPA will propose action on Alaska’s 

SO2 BACT determinations in a separate, 

future action. 

iii. University of Alaska Fairbanks 

Campus Power Plant 

The Fairbanks Campus Power Plant is 

an existing stationary source owned and 

operated by the University of Alaska 

Fairbanks, which consists of two coalfired boilers installed in 1962 that were 

later replaced by a circulating fluidized 

bed (CFB) dual fuel-fired boiler (coal 

and biomass) rated at 295.6 MMBtu per 

hour. Other emission units at the source 

include a backup diesel generator, 

diesel-fired boilers, engines, and a coal 

handling system for the new dual-fuel 

fired boiler. 

In the Fairbanks Revised 189(d) Plan, 

Alaska updated its Air Quality Control 

Plan regarding the Fairbanks Campus 

Power Plant to reflect permanently 

removed emission units, add new diesel 

boilers and engines, update the PM2.5

BACT determinations for small dieselfired boilers and large and small 

engines, correct typographical errors, 

and improve clarity.117 Alaska also 

added updated SO2 BACT 

determinations for the Fairbanks 

Campus Power Plant. 

With respect to the small diesel-fired 

boilers (EUs 17 through 22), Alaska 

updated its BACT determination for 

PM2.5 to consist of a partial limit on 

hours of operation, an emission limit of 

0.016 lb/MMBtu,118 compliance with 40 

CFR part 63, subpart JJJJJJ, and work 

practice standards. Alaska evaluated 

whether installation of a scrubber was 

feasible for these boilers and determined 

that it was economically infeasible.119

Alaska noted that taking into 

consideration the enforceable limit on 

operation, the combined potential to 

emit of PM2.5 for the six boilers is two 

tons per year. 

With respect to large diesel fired 

engines (EUs 8 and 35) and small diesel 

fired engines (EUs 24, 26, 27, 29, and 

34), 120 Alaska reevaluated the 

feasibility of add-on PM2.5 controls, 

namely a diesel particulate filter 

(DPF).121 EUs 24, 29, and 34 are limited 

to 100 hours per year of non-emergency 

operation, so additional BACT controls 

were not evaluated for these units. 

Alaska determined that a DPF is not 

technologically feasible for EU 8 due to 

an unacceptable increase in back 

pressure. Alaska determined that DPFs 

were technologically feasible for the 

other engines, but Alaska determined 

that the high cost per unit of emissions 

reductions rendered them economically 

infeasible. Updating the costeffectiveness analysis to reflect 

comments from the EPA’s Technical 

Support Document,122 Alaska 

determined that the cost-effectiveness 

ranged from over $17,000 at EU 26 to 

over $20,000 per ton of PM2.5 reduced 

at EU 27. Alaska stated that EU 35 has 

potential PM2.5 emissions of 0.03 tons 

per year, which is an order of magnitude 

lower than the two other diesel engines, 

EUs 26 and 27. Therefore, Alaska did 

not perform a cost analysis for installing 

and operating a DPF on EU 35 as it 

would have an even higher cost per ton 

estimate than EUs 26 and 27. 

Furthermore, Alaska noted that EU 35 is 

limited to 100 hours per calendar year 

of non-emergency operation and 

required to combust ULSD under the 

existing Federal NSPS Subpart IIII 

requirements.123

Alaska removed its BACT evaluation 

and determinations for NOX because the 

EPA approved a comprehensive NOX

precursor demonstration.124

Alaska also submitted conditions 

from Air Quality Control Minor Permit 

AQ0316MSS08 Revision 1 (University 

of Alaska Fairbanks (UAF)—University 

of Alaska Fairbanks Campus) (UAF 

Permit). The UAF Permit conditions 

include enforceable PM2.5 BACT 

emissions limitations comprised of 

numerical emissions limits and work 

practice standards with associated 

monitoring, recordkeeping, and 

reporting. The permits are included in 

the docket for this action.125

The EPA previously reviewed 

Alaska’s BACT evaluation for the 

Fairbanks Campus Power Plant.126 In 

this action, the EPA is proposing to 

approve Alaska’s updated PM2.5 BACT 

determinations for the small diesel-fired 

boilers (EUs 17 through 22), large dieselfired engines (EUs 8 and 35), and small 

diesel-fired engines (EUs 24, 26, 27, 29, 

and 34) at the Fairbanks Campus Power 

Plant. The EPA previously approved 

Alaska’s PM2.5 BACT determinations for 

EUs 8, 17–19, 24, and 29. Alaska’s 

updates are consistent with these past 

approvals. With respect to EUs 26, 27, 

and 35, the EPA proposes to approve 

Alaska’s economic infeasibility 

demonstrations for DPFs. The EPA is 

proposing to approve Alaska’s PM2.5

BACT emissions limits for small dieselfired boilers (EUs 17 through 22), large 

diesel-fired engines (EUs 8 and 35), and 

small diesel-fired engines (EUs 24, 26, 

27, 29, and 34) at the Fairbanks Campus 

Power Plant, which consist of numerical 

emissions limits, limits on operation, 

fuel requirements, and work practice 

standards. 

Therefore, the EPA proposes to 

approve the submitted revisions to State 

Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7 related to direct 

PM2.5 emissions and NOX emissions127

from the Fairbanks Campus Power Plant 


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128See section III.A of this preamble for the 

specific permit conditions proposed to be approved. 

129State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–316. 

130See State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–342. 

131State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–327. 

132See Hedgpeth, Z. (August 24, 2022). Review of 

Best Available Control Technology analyses 

submitted for the Golden Valley Electric 

Association (GVEA) Zehnder and North Pole Power 

Plants as part of the Fairbanks PM2.5

Nonattainment SIP. U.S. Environmental Protection 

Agency, Region 10, Laboratory Services and 

Applied Science Division, EPA–R10–OAR–2022– 

0115. 

133 Id. at p. 11. 

134The EPA is not proposing to approve the NOX

related emissions limits as meeting BACT for NOX. 

For some emission units, Alaska imposed NOX

emissions limits as surrogates for direct PM2.5

emissions. 

135State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–267. 

136See State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7–300. 

137See Hedgpeth, Z. (August 24, 2022). Review of 

Best Available Control Technology analyses 

submitted for the Golden Valley Electric 

Association (GVEA) Zehnder and North Pole Power 

Plants as part of the Fairbanks PM2.5

Nonattainment SIP. U.S. Environmental Protection 

Agency, Region 10, Laboratory Services and 

Applied Science Division, EPA–R10–OAR–2022– 

0115. 

138 Id. at p. 11. 

139The EPA is not proposing to approve the NOX

related emissions limits as meeting BACT for NOX. 

For some emission units, Alaska imposed NOX

emissions limits as surrogates for direct PM2.5

emissions. 

140See section III.A of this preamble for the 

specific permit conditions proposed to be approved. 

and the submitted conditions from the 

UAF Permit128 as satisfying CAA 

section 189(b) and 40 CFR 51.1010. 

The EPA is not proposing to take 

action on Alaska’s SO2 BACT 

determinations in State Air Quality 

Control Plan, Vol. III, Appendix III.D.7.7 

at this time for the same reasons 

discussed in the preceding paragraphs 

regarding the Chena Power Plant. If the 

EPA does not finalize approval of the 

SO2 precursor demonstration, then the 

EPA will propose action on Alaska’s 

SO2 BACT determinations in a separate, 

future action. 

iv. Zehnder Facility 

The Zehnder Facility (Zehnder) is an 

electric generating facility that combusts 

distillate fuel in combustion turbines to 

provide power to the Golden Valley 

Electric Association (GVEA) grid. The 

power plant contains two fuel oil-fired 

simple cycle gas combustion turbines 

(each unit rated at 268 MMBtu per hour) 

and two diesel-fired generators (electromotive diesels) used for emergency 

power and to serve as black start 

engines for the GVEA generation 

system. The primary fuel is stored in 

two 50,000 gallon above-ground storage 

tanks. Turbine startup fuel and electromotive diesels primary fuel is stored in 

a 12,000 gallon above ground storage 

tank. 

In the Fairbanks Revised 189(d) Plan, 

Alaska revised its Air Quality Control 

Plan for the Zehnder Facility to correct 

errors and improve clarity.129 Alaska 

also submitted conditions from Air 

Quality Control Minor Permit 

AQ0109MSS01 Revision 1 (Golden 

Valley Electric Association—Zehnder 

Facility) (Zehnder Permit). The Zehnder 

Permit contains enforceable PM2.5 BACT 

emissions limitations for the emission 

units at the Zehnder Facility comprised 

of numerical emissions limits and work 

practice standards with associated 

monitoring, recordkeeping, and 

reporting. The permits are included in 

the docket for this action.130

Similar to the small diesel-fired 

boilers (EUs 17 through 22) at the 

Fairbanks Campus Power Plant 

discussed in the preceding paragraphs 

of section II.C of this preamble, Alaska 

imposed, in the Fairbanks Serious Plan 

and Fairbanks 189(d) Plan, an erroneous 

emissions limit on the small diesel fired 

boilers at the Zehnder Facility. The 

revised Air Quality Control Plan and 

associated conditions in the Zehnder 

Permit reflect the corrected limit.131

The EPA previously reviewed 

Alaska’s BACT evaluation for the 

Zehnder Facility.132 In EPA’s prior 

analysis, the EPA agreed with Alaska’s 

BACT determinations for PM2.5. For the 

turbines, no technologically feasible 

add-on control options exist to reduce 

PM2.5 emissions. For the emergency 

generators, the EPA agreed that the 

limits on annual hours of operation of 

100 hours per year or less will result in 

add-on control equipment such as DPF 

being cost prohibitive. Further, the EPA 

stated that similar to the turbines, no 

technologically feasible add-on control 

options exist to reduce PM2.5 emissions 

from the small diesel and propane fired 

boilers.133

Thus, in this action, the EPA proposes 

to approve the submitted revisions to 

State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.7 related to direct 

PM2.5 emissions and NOX134 emissions 

from Zehnder and the submitted 

Zehnder Permit conditions as satisfying 

CAA section 189(b) and 40 CFR 

51.1010. 

The EPA is not proposing to take 

action on Alaska’s SO2 BACT 

determinations in State Air Quality 

Control Plan, Vol. III, Appendix III.D.7.7 

at this time for the same reasons 

discussed in the preceding paragraphs 

regarding the Chena Power Plant. If the 

EPA does not finalize approval of the 

SO2 precursor demonstration, then the 

EPA will propose action on Alaska’s 

SO2 BACT determinations in a separate, 

future action. 

v. North Pole Power Plant 

The North Pole Power Plant is an 

electric generating facility that combusts 

distillate fuel in combustion turbines to 

provide power to the Golden Valley 

Electric Association (GVEA) grid. The 

power plant contains two fuel oil-fired 

simple cycle gas combustion turbines 

(each unit rated at 672 MMBtu per 

hour), two fuel oil-fired combined cycle 

gas combustion turbines (each unit rated 

at 455 MMBtu per hour), one fuel oilfired emergency generator, and two 

propane-fired boilers. 

In the Fairbanks Revised 189(d) Plan, 

Alaska revised its Air Quality Control 

Plan for the North Pole Power Plant to 

correct errors and improve clarity.135

Alaska also submitted conditions from 

Air Quality Control Minor Permit 

AQ0110MSS01 Revision 1 (Golden 

Valley Electric Association—North Pole 

Power Plant) (NPPP Permit). The NPPP 

Permit conditions include enforceable 

PM2.5 BACT emissions limitations for 

the emission units at the North Pole 

Power Plant comprised of numerical 

emissions limits and work practice 

standards with associated monitoring, 

recordkeeping, and reporting. The 

permits are included in the docket for 

this action.136

The EPA previously reviewed 

Alaska’s BACT evaluation for the North 

Pole Power Plant.137 Similar to the 

Zehnder facility discussion in the 

preceding paragraphs in this section 

II.C, the EPA agreed with Alaska that no 

additional PM2.5 BACT controls are 

feasible for emissions units at the North 

Pole Power Plant.138 Thus, in this 

action, the EPA proposes to approve the 

submitted revisions to State Air Quality 

Control Plan, Vol. III, Appendix III.D.7.7 

related to direct PM2.5 emissions and 

NOX139 emissions from the North Pole 

Power Plant and the submitted NPPP 

Permit conditions 140 as satisfying CAA 

section 189(b) and 40 CFR 51.1010. 

The EPA is not proposing to take 

action on Alaska’s SO2 BACT 

determinations in State Air Quality 

Control Plan, Vol. III, Appendix III.D.7.7 

at this time for the same reasons 

discussed in the preceding paragraphs 

regarding the Chena Power Plant. If the 

EPA does not finalize approval of the 

SO2 precursor demonstration, then the 

EPA will propose action on Alaska’s 

SO2 BACT determinations separately. 


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1616 Federal Register / Vol. 90, No. 5 / Wednesday, January 8, 2025 / Proposed Rules 

141State Air Quality Control Plan, Vol. II, section 

III.D.7.7.12 (adopted November 5, 2024). 

142State Air Quality Control Plan, Vol. II, section 

III.D.7.9.2.3, Table 7.9–9. 

143The term ‘‘applicable attainment date’’ is 

defined at 40 CFR 51.1000 to mean: ‘‘the latest 

statutory date by which an area is required to attain 

a particular PM2.5 NAAQS, unless EPA has 

approved an attainment plan for the area to attain 

such NAAQS, in which case the applicable 

attainment date is the date approved under such 

attainment plan. If EPA grants an extension of an 

approved attainment date, then the applicable 

attainment date for the area shall be the extended 

date.’’ 

144 40 CFR 51.1011(b)(5). 

145 88 FR 84626, December 5, 2023, at p. 84676. 

146State Air Quality Plan, Vol. II, section III.D.7.9 

(adopted November 5, 2024). 

c. Alaska’s Identification and Adoption 

of Additional Measures and 

Demonstration of Five Percent 

Reduction in Emissions Pursuant to 

CAA Section 189(d) 

The Fairbanks Revised 189(d) Plan 

retained the identification of all sources 

of direct PM2.5 emissions and PM2.5 plan 

precursors, identification of all potential 

controls to reduce direct PM2.5

emissions and PM2.5 plan precursors, 

and reevaluation of previously rejected 

control measures included in the initial 

Fairbanks 189(d) Plan, as well as 

identification of the MSMs adopted into 

any SIP or used in practice to control 

emissions in any state. 

As part of its reevaluation of control 

measures, Alaska provided additional 

information for many of the control 

measures considered in the BACM 

analysis. The Fairbanks Revised 189(d) 

Plan includes additional consideration 

of banning installation of solid-fuel 

devices in new construction, limiting 

heating oil to ultra-low sulfur diesel, dry 

wood requirements, emissions controls 

for small area sources, mobile sources, 

and MSMs.141

Alaska identified a burn-down period 

as part of other jurisdictions’ solid fuelfired heating device curtailment 

program. Accordingly, Alaska adopted a 

burn down period of three hours for 

solid-fuel heating devices that begins 

upon the effective date and time of a 

curtailment announcement. In addition, 

Alaska added specific requirements to 

document economic hardship as part of 

a NOASH curtailment program waiver 

for solid-fuel devices. 

Regarding the requirement to 

demonstrate five percent annual 

reductions, Alaska included in the 

Fairbanks Revised 189(d) Plan a control 

strategy analysis that demonstrates 

annual reductions of PM2.5 are greater 

than five percent through 2027, Alaska’s 

projected attainment year.142 Alaska 

noted that the State can demonstrate 

either five percent annual reductions in 

emissions of direct PM2.5 or a five 

percent annual reductions in emissions 

of a PM2.5 plan precursor. Alaska elected 

to demonstrate five percent annual 

reductions in direct PM2.5 emissions. 

Thus, the EPA is proposing to approve 

the control strategy included in the 

Fairbanks Revised 189(d) Plan as 

meeting the requirements of CAA 

section 189(d) and 40 CFR 51.1010(c). 

D. Attainment Demonstration and 

Modeling 

1. Statutory and Regulatory 

Requirements Regarding the Attainment 

Demonstration and Modeling 

Pursuant to CAA sections 188(c) and 

189(b) and 40 CFR 51.1003(b) and 

51.1011(b), for nonattainment areas 

reclassified as Serious, the state must 

submit an attainment demonstration as 

part of the Serious Plan that meets the 

requirements of 40 CFR 51.1011. 

Similarly, pursuant to 40 CFR 

51.1003(c), for Serious areas subject to 

CAA section 189(d) for failing to attain 

by the Serious area attainment date, the 

state must submit an attainment 

demonstration as part of the 189(d) plan 

that meets the requirements of 40 CFR 

51.1011. On September 2, 2020, the EPA 

determined that the Fairbanks PM2.5

Nonattainment Area failed to attain the 

2006 24-hour PM2.5 NAAQS by the 

December 31, 2019, Serious area 

attainment date. Therefore, the EPA is 

proposing to evaluate any previously 

unmet Serious area planning obligations 

based on the current, applicable 

attainment date appropriate under CAA 

section 189(d) and not the original 

Serious area attainment date.143 In 

accordance with CAA section 

172(a)(2)(A) and 40 CFR 51.1004(a)(3), 

the projected attainment date for 

Serious nonattainment areas subject to 

CAA section 189(d) shall be as 

expeditious as practicable, but no later 

than five years following the effective 

date of the EPA’s finding that the area 

failed to attain by the original Serious 

area attainment date, except that the 

Administrator may extend the 

attainment date to the extent the 

Administrator deems appropriate, for a 

period no greater than 10 years from the 

effective date of the EPA’s 

determination that the area failed to 

attain, considering the severity of 

nonattainment and the availability and 

feasibility of pollution control measures. 

In accordance with 40 CFR 51.1011, the 

attainment demonstration must meet 

four requirements: 

a. Identify the projected attainment 

date for the Serious nonattainment area 

that is as expeditious as practicable; 

b. Meet the requirements of 40 CFR 

part 51, appendix W and include 

inventory data, modeling results, and 

emissions reduction analyses on which 

the state has based its projected 

attainment date; 

c. The base year for the emissions 

inventories shall be one of the 3 years 

used for designations or another 

technically appropriate inventory year if 

justified by the state in the plan 

submission; and 

d. The control strategies modeled as 

part of a Serious area attainment 

demonstration shall be consistent with 

the control strategies required pursuant 

to 40 CFR 51.1003 and 51.1010 

(including the specific requirements in 

40 CFR 51.1010(c)) for Serious areas that 

fail to attain. 

Further, in accordance with 40 CFR 

51.1011(b)(5), the attainment plan must 

provide for implementation of all 

control measures needed for attainment 

as expeditiously as practicable. 

Additionally, all control measures must 

be implemented no later than the 

beginning of the year containing the 

applicable attainment date, 

notwithstanding the BACM 

implementation deadline requirements 

in 40 CFR 51.1010.144

2. Summary of the EPA’s Prior 

Rulemaking Regarding Attainment 

Demonstration and Modeling 

The EPA disapproved Alaska’s 

attainment demonstration in the initial 

Fairbanks 189(d) Plan because it did not 

fully meet CAA requirements.145 As part 

of the attainment demonstration, the 

state must identify the projected 

attainment date that is as expeditious as 

practicable. Alaska did not adopt and 

implement all available control 

measures. The correct identification of 

the most expeditious attainment date 

requires an evaluation based upon 

expeditious implementation of the 

required emissions controls. Therefore, 

the EPA could not assess whether 

Alaska identified the expeditious 

attainment date for modeling purposes. 

3. Summary of the State’s Submission 

Regarding Attainment Demonstration 

and Modeling 

The State included an updated 

attainment demonstration in the 

Fairbanks Revised 189(d) Plan.146 In the 

plan, Alaska asserted that calendar year 

2027 reflects attainment ‘‘as 

expeditiously as practicable,’’ based on 

air quality improvements from the base 

year to attainment year, as measured by 

the quantified emissions reductions 


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147State Air Quality Plan, Vol. II, section III.D.7.9. 148State Air Quality Plan, Vol. II, section III.D.7.6, 

Table 7.6–10. 

149State Air Quality Plan, Vol. II, section III.D.7.9, 

Table 7.9–1. 

associated with the implementation of 

control measures.147

Alaska noted that for attainment 

modeling, five-year design values are 

generally recommended. For the earlier 

Fairbanks Serious Plan, the base year 

modeling design value was 131.6 mg/m3. 

However, the latest five-year (2017– 

2021) design value is 64.9 mg/m3 at the 

North Pole air quality monitor (Hurst 

Road), the area of expected highest 

PM2.5 concentrations in the Fairbanks 

PM2.5 Nonattainment Area. As part of 

updating its attainment analysis, Alaska 

identified this five-year design value of 

64.9 mg/m3 as the base year modeling 

design value for the Fairbanks Revised 

189(d) Plan. 

Building on the 2020 base year 

emissions inventory, Alaska developed 

a series of future year emissions 

inventories for each calendar year from 

2020 through 2029. Alaska noted that 

each of these future year inventories 

accounted for growth in source activity 

over time (e.g., increases in residential 

heating emissions resulting from 

forecasted housing growth). The 

emissions inventory also accounted for 

emissions reductions associated with 

both on-going state and local control 

programs (such as the Wood Stove 

Change Out and Solid Fuel-Burning 

Appliance Curtailment programs), along 

with other control measures included in 

the SIP that were adopted since the area 

was classified as a Serious area. 

Alaska stated that source activity 

growth rates used to project the 2020 

base year inventory emissions in 

calendar years 2021 through 2029 were 

generally based on the 2020–2024 and 

2024–2035 annualized growth rates by 

source sector included in the Fairbanks 

Revised 189(d) Plan.148 However, 

Alaska noted that the source activity 

growth rate for space heating was 

capped after model year 2027, and 

claimed this is due to the difficulty in 

reliably forecasting long-term energy 

prices and the likely peak in energy 

costs in 2024. Alaska also stated that the 

effects of the Federal mobile source and 

fuel control programs in projecting 

mobile source emissions from 2021 

through 2029 were accounted for using 

the EPA’s MOVES3 vehicle emissions 

model. 

Alaska included a list of the state and 

local control measures for which 

emissions benefits were quantified and 

included in the attainment date 

analysis.149 Further, Alaska included a 

phase-in forecast for each control 

measure for 2020–2027 inventory years. 

See Table 4 of this preamble for a 

summary of these control measures: 

TABLE 4—ALASKA CONTROL MEASURES AND PHASE-IN SCHEDULE

Control measure 

Percent compliance 2027 Projected emissions 

(tons per episodic day) 

2020 Details 

Base 

year 

2027 

Attainment 

year PM2.5 SO2

Fairbanks Wood Stove Change 

Out Program.

2,791 5,628 1.09 ........................................... 0.11 ........................................... Based on funding from the 

2016, 2017, 2018, 2019– 

2020, 2021, and 2022 Targeted Airshed Grants. 

Solid Fuel-Burning Appliance 

Curtailment Program.

30% 38% Stage 1: 0.02; Stage 2: 0.12 ..... Stage 1:—0.000; Stage 2:— 

0.02.

In winter 2022–2023, Alaska 

conducted an observational 

field study from which compliance was estimated to be 

38.1%. 

Shift to diesel no. 1 fuel oil ....... n/a 50% 0.02 ........................................... 1.73 ........................................... This measure required a onetime shift from the current mix 

of diesel no. 2 and diesel no. 

1 heating oil refined and sold 

in the nonattainment area by 

September 2022. 

Requires commercially sold 

wood to be dry before sale.

n/a 50% 0.06 ........................................... Less than 0.01 .......................... Requires commercially sold 

wood after October 1, 2021, 

to be dry, or if sold as 8-ft 

length rounds, requires proof 

of proper/adequate storage 

for drying by the buyer. 

Removal of all uncertified devices & cordwood outdoor 

hydronic heaters.

0% 30% 0.25 ........................................... ¥0.01 ........................................ 2024 is first year of implementation. Compliance rate estimates based on existing and 

on-going public education and 

outreach efforts. 

2.0 g/hr and 0.10 lb/MMBtu certified emission rates for new 

or re-conveyed wood devices.

22% 35% 0.09 ........................................... Less than 0.01 .......................... The compliance rate estimated 

for this measure reflect the 

volume of home sales (projected from historical data) 

coupled with the requirement 

to register wood-fired heating 

devices upon sale or conveyance of a property. 

Removal of coal heaters ........... n/a 25% Less than 0.01 .......................... Less than 0.01.


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1618 Federal Register / Vol. 90, No. 5 / Wednesday, January 8, 2025 / Proposed Rules 

150See State Air Quality Plan, Vol. III, Appendix 

III.D.7.9. 

TABLE 4—ALASKA CONTROL MEASURES AND PHASE-IN SCHEDULE—Continued 

Control measure 

Percent compliance 2027 Projected emissions 

(tons per episodic day) 

2020 Details 

Base 

year 

2027 

Attainment 

year PM2.5 SO2

Wood-fired devices may not be 

primary or only heating 

source.

0% 20% 

(existing 

homes); 

40% (new 

homes) 

0.09 ........................................... Less than 0.01 .......................... Beginning in 2024, compliance 

rates of 20% for new home 

sales (discounted for large 

lot, 2-acre cabin exemption) 

and 40% for home resales. 

The new home sale compliance rate is discounted from 

40% to 20% to account for 

the estimated portion of large 

lot (greater than 2 acre) cabins which are exempted from 

this requirement. 

NOASH/Exemption requirements.0% 50% Less than 0.01 .......................... Less than 0.01 .......................... Compliance rates reflect projected penetration rate increases associated with annual renewal and device registration requirements, proper 

installation and maintenance 

determinations from thirdparty verifiers, and requirements for catalyst replacement when manufacturer-recommended catalyst useful life 

is reached (estimated at six 

years averaged across manufacturers). These elements 

are also coupled with projected impacts from the 

NOASH reduction program 

funded under currently secured TAGs. 

Alaska noted that, based on these 

phase-in forecasts, a detailed 

spreadsheet was developed to calculate 

PM2.5 and SO2 emissions reductions 

within the space heating sector for each 

measure in each inventory year. 150 The 

source activity data includes device and 

fuel splits, emission factors, and 

methods used to calculate control 

measure emissions benefits to support 

the control inventories developed for 

the attainment date analysis. Alaska 

further stated that the control measure 

emissions benefits calculations also 

account for the effects of overlap 

between measures that impact the same 

source category, properly eliminating 

double counting. 

Alaska stated that projected emissions 

control inventories for each year from 

2020 through 2029 were prepared to 

support the analysis of expeditious 

attainment. Full modeling runs were 

completed for 2029, 2027, and 2026 in 

that order. After the 2029 modeling 

results demonstrated attainment of the 

PM2.5 NAAQS, 2027 was selected as the 

next year to evaluate expeditious 

attainment. 

To begin analyzing the 2027 

attainment year, Alaska noted that the 

2027 episodic modeling inventory was 

incorporated into the CMAQ air quality 

model. Modeled concentration outputs 

for this 2027 control inventory run were 

post-processed for each grid cell 

corresponding to ambient air quality 

monitors for which design values could 

be computed and processed through 

Alaska’s Speciated Modeled Attainment 

Test (SMAT) tool (see State Air Quality 

Control Plan, Vol. II, section III.D.7.8.9). 

Alaska stated that the modeled design 

value at the controlling North Pole 

(Hurst Road) air quality monitor was 

found to be 31.9 mg/m3, below the 35 mg/ 

m3 NAAQS for 24-hour PM2.5 and thus 

demonstrating modeled attainment by 

2027. 

To evaluate whether attainment could 

be advanced any sooner than 2027, 

Alaska compiled another emissions 

inventory for the 2026 model year. The 

2026 CMAQ gridded outputs were then 

post-processed for the key monitorbased grid cells through the SMAT tool 

to develop modeled design values that 

reflected penetration of the State’s 

control strategy package in 2026. Alaska 

stated that the 2026 modeled design 

value at the North Pole (Hurst Road) 

monitor was found to be 38.1 mg/m3, 

which exceeds the 35 mg/m3 NAAQS. 

As shown in Table 5 of this preamble, 

modeled design values in 2027 at all 

three regulatory air quality monitor 

locations in the Fairbanks PM2.5

Nonattainment Area are below the 35 

mg/m3 24-hour PM2.5 NAAQS. Alaska 

noted that the modeled design value at 

the controlling North Pole (Hurst Road) 

monitor is 31.9 mg/m3, more than 3 mg/ 

m3 below the NAAQS, which provides 

a ‘‘buffer’’ to account for concentrations 

in unmonitored grid cells across the 

nonattainment area. Modeled 2027 

design values at the other two monitors 

near downtown Fairbanks are well 

below the PM2.5 NAAQS. 


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Federal Register / Vol. 90, No. 5 / Wednesday, January 8, 2025 / Proposed Rules 1619 

151State Air Quality Control Plan, Vol. II, section 

III.D.7.9.3 

152State Air Quality Control Plan, Vol. II, section 

III.D.7.10, Table 7.10–4. 

153State Air Quality Control Plan, Vol. III, 

Appendix III.D.7.9, at p. Appendix III.D.7.14–12. 

TABLE 5—FAIRBANKS MODELED ATTAINMENT SUMMARY

Fairbanks PM2.5 air quality 

monitor 

Base year 2020 

5-year PM2.5

modeling design 

value (μg/m3), 

2017–2021 

Future 5-year 

PM2.5 modeling 

design value 

(μg/m3), 2026 

Future 5-year 

PM2.5 modeling 

design value 

(μg/m3), 2027 

North Pole (Hurst Road) ............................................................................................ 64.9 38.1 31.9 

NCORE ...................................................................................................................... 27.7 19.8 18.4 

A Street ...................................................................................................................... 34.8 24.5 22.7 

Source: State Air Quality Plan, Vol. II, section III.D.7.9, Table 7.9–12. 

Alaska noted that even if emission 

controls were applied for precursor 

pollutants within applicable source 

sectors for which precursor significance 

determinations have been made (i.e., 

SO2 emissions from major stationary 

sources in the Fairbanks PM2.5

Nonattainment Area), the reduction in 

secondary PM2.5 from such controls 

would not be sufficient to advance 

attainment sooner than 2027.151

Therefore, Alaska asserted that this 

evaluation demonstrates that 2027 is the 

most expeditious attainment date based 

on currently available data and 

demonstrate attainment ‘‘as 

expeditiously as practicable.’’ 

4. The EPA’s Evaluation and Proposed 

Action Regarding the Attainment 

Demonstration and Modeling 

The EPA proposes to approve 

Alaska’s attainment demonstration as 

meeting the requirements under 40 CFR 

51.1011(b). Alaska demonstrated that 

the 2027 projected attainment date for 

the Serious nonattainment area is as 

expeditious as practicable. The 

attainment demonstration meets the 

requirements of Appendix W and 

includes inventory data, modeling 

results, and emissions reduction 

analyses on which the state has based 

its projected attainment date. As 

discussed in section II.A of this 

preamble, the base year for the 

emissions inventories for Alaska was 

2020, which the EPA is proposing to 

determine is the technically appropriate 

inventory year. The EPA is proposing to 

determine that the control strategies in 

Alaska’s SIP as rectified by the 

Fairbanks Revised 189(d) Plan satisfy 

the requirements of 40 CFR 51.1010. 

Therefore, the control strategies 

modeled as part of the attainment 

demonstration are consistent with the 

control strategies required pursuant to 

40 CFR 51.1003 and 51.1010. With 

respect to the required timeframe for 

obtaining emissions reductions, all 

control measures needed for attainment 

will be implemented as expeditiously as 

practicable and implemented to attain 

the PM2.5 NAAQS by 2027. 

Pursuant to CAA section 172(a)(2)(A) 

and 40 CFR 51.1004(a)(3), the EPA is 

proposing to extend the attainment date 

for the Fairbanks PM2.5 Nonattainment 

Area to December 31, 2027. As shown 

in Table 5 of this preamble, the 2020 

base year design value at the Hurst Road 

monitoring station is 64.9 mg/m3. This 

design value is well above the PM2.5 24- 

hour NAAQS of 35 mg/m3, indicating 

the air quality problem in the Fairbanks 

PM2.5 Nonattainment Area remains 

severe. However, Alaska has 

demonstrated that attainment earlier 

than 2027 is not feasible. Moreover, the 

EPA has reviewed Alaska’s evaluations 

(and re-evaluations) of available control 

measures and proposes to determine 

that Alaska’s control strategy meets the 

requirements of CAA section 189(b) and 

189(d) and 40 CFR 51.1010. By 

extension, the EPA proposes to 

determine that there are no other 

feasible measures that Alaska could 

implement that would advance 

attainment to a date earlier than 

December 31, 2027. 

As discussed in section II.E of this 

preamble regarding Reasonable Further 

Progress, the primary drivers of 

emissions reductions will be continued 

implementation of the wood stove 

change out program, the Solid FuelBurning Appliance Curtailment 

Program, and the switch from diesel no. 

2 fuel oil to diesel no. 1 fuel oil. The rate 

of wood stove change-outs in a single 

season is constrained based on the 

availability of certified installers and 

residential demand. Similarly, higher 

sulfur fuel cannot feasibly be eliminated 

from the Fairbanks PM2.5 Nonattainment 

Area until 2026152 due to the time 

necessary to expend all residual diesel 

no. 2 fuel oil and for diesel no. 1 to fully 

flush out any remaining higher sulfur 

residue. Finally, Alaska conducted a 

recent assessment of compliance with 

the Solid Fuel-Burning Appliance 

Curtailment Program that indicated a 

compliance rate of 38 percent.153 Given 

the variability of compliance with this 

program in past, Alaska does not project 

a near-term improvement in the 

compliance rate. Therefore, the EPA has 

considered the severity of 

nonattainment and the availability and 

feasibility of control measures as 

required under CAA section 

172(a)(2)(A) and 40 CFR 51.1004(a)(3). 

E. Reasonable Further Progress 

1. Statutory and Regulatory 

Requirements Regarding Reasonable 

Further Progress 

Pursuant to CAA section 172(c) and 

40 CFR 51.1012, each attainment plan 

for a PM2.5 nonattainment area shall 

include Reasonable Further Progress 

(RFP) provisions that demonstrate that 

control measures in the area will 

achieve such annual incremental 

reductions in emissions of direct PM2.5

and PM2.5 plan precursors as are 

necessary to ensure attainment of the 

applicable PM2.5 NAAQS as 

expeditiously as practicable. As 

discussed in section I of this preamble, 

on September 2, 2020, the EPA 

determined that the Fairbanks PM2.5

Nonattainment Area failed to attain the 

2006 24-hour PM2.5 NAAQS by the 

applicable December 31, 2019, Serious 

area attainment date. Therefore, the EPA 

is proposing to evaluate any previously 

unmet Serious area planning 

obligations, including RFP and 

quantitative milestone requirements, 

based on the current, applicable 

attainment date appropriate under CAA 

section 189(d) and not the original 

Serious area attainment date. In 

accordance with 40 CFR 51.1012, the 

RFP plan shall include all of the 

following: 

a. A schedule describing the 

implementation of control measures 

during each year of the applicable 

attainment plan. Control measures for 

Moderate area attainment plans are 

required in 40 CFR 51.1009, and control 


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1620 Federal Register / Vol. 90, No. 5 / Wednesday, January 8, 2025 / Proposed Rules 

154For an evaluation of motor vehicle emission 

budgets, see section II.H of this preamble. 

155 88 FR 84626, December 5, 2023, at p. 84676. 

156Adopted November 5, 2024. 

157RFP provisions in prior SIP submissions for 

the Fairbanks PM2.5 Nonattainment Area reflected 

varying projected attainment dates. Initially Alaska 

submitted an RFP plan in the Fairbanks Serious 

Plan based on the projected attainment year of 

2029. Alaska withdrew and replaced the RFP plan 

in the Fairbanks 189(d) plan based on the revised 

2024 attainment projection. 

158See State Air Quality Plan, Vol. II, section 

III.D.7.10.2. 

159State Air Quality Plan, Vol. II, section 

III.D.7.9.1.1. 

160 Id. 

161State Air Quality Plan, Vol. II, section 

III.D.7.10.3.3. 

162 Id. 

163 Id. 

measures for Serious area attainment 

plans are required in 40 CFR 51.1010. 

b. RFP projected emissions for direct 

PM2.5 and all PM2.5 plan precursors for 

each applicable milestone year, based 

on the anticipated implementation 

schedule for control measures required 

by 40 CFR 51.1009 and 51.1010. For 

purposes of establishing motor vehicle 

emissions budgets for transportation 

conformity purposes (as required in 40 

CFR part 93, subpart A) for a PM2.5

nonattainment area, the state shall 

include in its RFP submission an 

inventory of on-road mobile source 

emissions in the nonattainment area for 

each milestone year.154

c. An analysis that presents the 

schedule of control measures and 

estimated emissions changes to be 

achieved by each milestone year, and 

that demonstrates that the control 

strategy will achieve reasonable 

progress toward attainment between the 

applicable base year and the attainment 

year. The analysis shall rely on 

information from the base year 

inventory for the nonattainment area 

required in 40 CFR 51.1008(a)(1) and 

the attainment projected inventory for 

the nonattainment area required in 40 

CFR 51.1008(a)(2), in addition to the 

RFP projected emissions required in 40 

CFR 51.1012(a)(2). 

d. An analysis that demonstrates that 

by the end of the calendar year for each 

milestone date for the area determined 

in accordance with 40 CFR 51.1013(a), 

pollutant emissions will be at levels that 

reflect either generally linear progress or 

stepwise progress in reducing emissions 

on an annual basis between the base 

year and the attainment year. A 

demonstration of stepwise progress 

must be accompanied by appropriate 

justification for the selected 

implementation schedule. 

2. Summary of the EPA’s Prior 

Rulemaking Regarding Reasonable 

Further Progress 

The EPA disapproved the RFP 

provisions in the Fairbanks Serious Plan 

and Fairbanks 189(d) Plan because the 

control strategies in those prior plans 

did not include all required control 

measures.155 This caused uncertainty as 

to whether the RFP provisions of those 

plans accurately projected progress 

towards the most expeditious 

attainment year, per CAA section 

172(c)(2) and 40 CFR 51.1012. 

3. Summary of the State’s Submission 

Regarding Reasonable Further Progress 

The Fairbanks Revised 189(d) Plan 

includes updated RFP provisions at 

State Air Quality Control Plan, Vol. II, 

section III.D.7.10.156 Consistent with the 

attainment demonstration provisions 

discussed in the preceding paragraphs, 

these updated RFP provisions reflect the 

attainment year of 2027.157 The updated 

RFP analysis includes a schedule that 

includes 2020 as the base year, 2027 as 

the attainment year, and the following 

years as RFP and quantitative milestone 

analysis years: 2023, 2026, and 2029.158

Alaska included an analysis of 

implementation of all control measures 

that establishes the scheduled phase-in 

of each measure adopted and estimation 

of emissions reductions for each 

significant pollutant (also accounting for 

the overlapping of measures to 

eliminate double counting) for each 

milestone year based on the phase-in 

schedule. Alaska calculated the RFP and 

quantitative milestone (QM) milestone 

year emissions reduction targets based 

on linear progress towards attainment 

by 2027. Based on the control measure 

phase-in schedule, Alaska calculated 

projected emissions reductions for each 

pollutant in each milestone year and 

compared these emissions reductions to 

their targets to evaluate linear progress 

toward attainment. 

Alaska has continued to assess the 

appropriate compliance rate estimate. 

As Alaska noted in the Fairbanks 

Revised 189(d) Plan, the State is 

currently utilizing funding from the 

2019–2020 TAG to purchase three 

dynamic message highway signs and an 

infrared camera and to expand staffing 

to increase compliance.159 Alaska 

continues to conduct field studies 

during the wintertime to observe 

compliance rates. Based on the recent 

2022–2023 wintertime field study, 

Alaska determined that the combined 

compliance rate in Fairbanks and the 

North Pole is 38.1 percent. Based on 

these observations and the increased use 

of TAG funding to improve compliance, 

Alaska increased its compliance 

estimate with the curtailment program 

to 38 percent for the 2023 model year, 

an increase from 30 percent in 2020. 

Alaska plans to conduct additional 

wintertime curtailment program 

compliance observations to inform 

anticipated improvements in 

compliance beyond 2023. For the 

attainment year projected emissions 

inventory, Alaska stated that it 

conservatively assumed no further 

compliance rate increases pending 

further evaluation of additional 

wintertime compliance observations.160

Alaska stated that direct PM2.5

emissions reductions achieved within 

the first two milestone years (2023 and 

2026) achieve stepwise progress.161

However, reductions in direct PM2.5

emissions in the attainment year of 2027 

reflect linear progress. According to 

Alaska’s submission, this is attributable 

to a spike in participation in the wood 

stove change out program anticipated by 

2027 (based on increased incentives and 

deadlines for older device turnover) and 

gradual improvements in household 

compliance with control strategies 

impacting solid fuel-burning devices. 

With respect to SO2, Alaska stated 

that SO2 emissions reductions are 

expected to be non-linear but includes 

early year (2023 and 2026) progress that 

significantly exceeds the linear progress 

trajectory.162 Alaska stated that this 

non-linearity in control measure 

reductions for SO2 is due to two causes. 

First, most of the measures designed to 

reduce direct PM2.5 through removal, 

curtailment, or replacement of solid-fuel 

devices trigger a shift from space 

heating devices that emit high levels of 

direct PM2.5 to oil-fired devices that 

emit very low levels of direct PM2.5 (but 

can lead to higher levels of SO2

emissions depending on the fuel sulfur 

content). Second, initial reductions in 

SO2 emissions are the result of Alaska 

implementing an SO2-specific control 

measure in 2022 mandating a shift from 

diesel no. 2 to diesel no. 1 heating oil. 

Thus, emissions reductions for SO2

exhibit stepwise rather than linear 

progress. 

Regarding NH3, Alaska stated that 

linearly established targets for NH3 will 

not be met until the forecasted 2027 

attainment year.163 Alaska noted that 

the increases in NH3 emissions are not 

due to control measure benefits or lack 

thereof. Although Alaska adopted and 

implemented control measures to 

reduce NH3, Alaska did not calculate 

any NH3 emissions reductions for these 

measures for the purposes of RFP due to 


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164 Id. at section III.D.7.10.3.2; See also State Air 

Quality Control Plan, Vol. III, Appendix III.D.7.10. 165 Id. at section III.D.7.10.3.3, Table 7.10–5. 166 Id. at section III.D.7.10.3.2, Table 7.10–4. 167 Id. at section III.D.7.10.3, Tables 7.10–4–7.10– 

5; Figures 7.10–3–7.10–5. Note that NH3 emissions 

are projected to increase from base year to the 

projected attainment year. As discussed in the 

preceding paragraphs regarding the control strategy, 

the EPA either has previously approved Alaska’s 

control strategy as meet planning requirements for 

sources of NH3. This is primarily because there are 

either no controls for sources of NH3 emissions in 

the Fairbanks PM2.5 Nonattainment Area or the 

direct PM2.5 emissions controls are sufficient to 

control NH3 emissions. 

168See CAA section 189, 42 U.S.C. 7513a, 

Addendum to the General Preamble, 59 FR 41998 

(August 16, 1994), at p. 42016. 

169 88 FR 84626, December 5, 2023, at p. 84636 

170 40 CFR 51.1013(a)(3). 

171 40 CFR 51.1013(a)(3)(ii). 

172 Id. 

173 81 FR 58010, Aug. 24, 2016, at pp. 58064, 

58104. 

174 Id. 

175 88 FR 84626, December 5, 2023, at p. 84676. 

the large uncertainty in NH3 emissions 

factors for key sources. 

4. The EPA’s Evaluation and Proposed 

Action Regarding Reasonable Further 

Progress 

The EPA is proposing to approve the 

Fairbanks Revised 189(d) Plan as 

meeting the RFP requirements in CAA 

section 172(c)(2) and 40 CFR 51.1012. 

The RFP provisions in the Fairbanks 

Revised 189(d) Plan meet each of the 

requirements in 40 CFR 51.1012(a)(1)– 

(4). First, the RFP provisions include a 

schedule describing the implementation 

of control measures during each year of 

the applicable attainment plan.164

Second, the Fairbanks Revised 189(d) 

Plan includes RFP projected emissions 

for direct PM2.5 and all PM2.5 plan 

precursors for each applicable milestone 

year based on the phase-in schedule.165

Third, the Fairbanks Revised 189(d) 

Plan includes an analysis that presents 

the schedule of control measures and 

estimated emissions changes to be 

achieved by each milestone year: 2023, 

2026, and 2029.166 This analysis relies 

on information from the base year 

inventory and attainment projected 

inventories in State Air Quality Control 

Plan, Vol. II, section III.D.7.8, as well as 

the RFP projected emissions. The 

analysis demonstrates that the control 

strategy will achieve reasonable 

progress toward attainment between the 

applicable base year and the attainment 

year.167

Finally, the Fairbanks Revised 189(d) 

Plan includes an analysis that 

demonstrates that by the end of the 

calendar year for each milestone date, 

pollutant emissions will be at levels that 

reflect either linear progress or stepwise 

progress in reducing emissions on an 

annual basis between the base year and 

attainment year. As discussed in section 

II.E.3 of this preamble, Alaska’s 

projections for reductions in direct 

PM2.5 reductions closely track linear 

progress. The EPA proposes to 

determine that the slight deviations 

from linear progress in the initial years 

of implementation are justified. The 

EPA recognizes the episodic nature of 

wood-stove change outs and the time lag 

between state enforcement and 

deterrence. 

With respect to SO2 emissions 

reductions, Alaska projects emissions 

well below linear progress in 2023 and 

2026 milestone years. As discussed in 

section II.E.3 of this preamble, the earlyyear reductions are due to near-term 

implementation of the control strategy 

requirement to switch to lower sulfur 

fuels. These early reductions are 

consistent with the overall goal of 

achieving attainment as expeditiously as 

practicable.168 The EPA proposes to 

determine that Alaska adequately 

justified the leveling off of SO2

emissions reductions in 2027 as due to 

the near-term implementation of the 

fuel switch as well as the increase in 

SO2 emissions from residents switching 

from solid fuel-fired heating devices to 

liquid fuel-fired heating devices to 

comply with other measures in the 

control strategy targeting sources of 

direct PM2.5. 

Finally, with respect to NH3, the EPA 

proposes to determine that Alaska 

adequately justified the increase in 

emissions. The EPA has previously 

approved Alaska control strategy for 

NH3, noting that sources in the 

Fairbanks PM2.5 Nonattainment Area 

emit a negligible amount of NH3 and 

there are no specific controls for the 

types of sources in the area.169

Therefore, the EPA is proposing to 

approve the Fairbanks Revised 189(d) 

Plan as meeting the RFP requirements in 

CAA section 172(c)(2) and 40 CFR 

51.1012. 

F. Quantitative Milestones 

1. Statutory and Regulatory 

Requirements Regarding the 

Quantitative Milestones 

In accordance with CAA section 

189(c)(1) and 40 CFR 51.1013, the state 

must submit in each attainment plan for 

a PM2.5 nonattainment area specific 

quantitative milestones that provide for 

objective evaluation of RFP toward 

timely attainment of the applicable 

PM2.5 NAAQS in the area. 

For an attainment plan submission for 

a Serious area subject to the 

requirements of CAA section 189(d) and 

40 CFR 51.1003(c), each plan shall 

contain quantitative milestones that 

provide for objective evaluation of 

reasonable further progress toward 

timely attainment of the applicable 

PM2.5 NAAQS in the area.170 At a 

minimum, each plan for an area subject 

to CAA section 189(d) must include 

QMs for tracking progress achieved in 

implementing the SIP control measures 

by each milestone date.171

In the preamble to the PM2.5 SIP 

Requirements Rule, the EPA stated that 

it interprets the CAA as allowing states 

to identify milestones that are suitable 

for the specific facts and circumstances 

of the attainment area.172 The EPA 

suggested possible metrics, including 

tracking air quality improvement, 

tracking emissions reductions, 

percentage implementation of control 

strategies, or percent compliance with 

implemented control measures.173

Finally, the EPA stated in the preamble 

that quantitative milestones will be met 

by showing that emissions reductions 

scheduled to be made between the SIP 

due date and the attainment date were 

actually achieved.174

Regarding the specific timeframe for 

the Fairbanks PM2.5 Nonattainment 

Area, per 40 CFR 51.1013(a)(4), each 

attainment plan submission for an area 

designated nonattainment for the 1997 

and/or 2006 PM2.5 NAAQS before 

January 15, 2015, shall contain 

quantitative milestones to be achieved 

no later than 3 years after December 31, 

2014, and every 3 years thereafter until 

the milestone date that falls within 3 

years after the applicable attainment 

date. 

2. Summary of the EPA’s Prior Action 

Regarding the Quantitative Milestones 

The EPA disapproved the quantitative 

milestones in the Fairbanks Serious 

Plan and Fairbanks 189(d) Plan because 

the control strategies in those prior 

plans did not include all required 

control measures.175 This caused 

uncertainty as the whether the 

quantitative milestones were based on 

progress towards the most expeditious 

attainment year. 

3. Summary of the State’s Submission 

Regarding the Quantitative Milestones 

Alaska submitted revised quantitative 

milestones in the Fairbanks Revised 

189(d) Plan. As noted in section II.E of 

this preamble, Alaska’s updated RFP 

analysis is based on a schedule that 

includes 2020 as the base year, 2027 as 

the attainment year, and the following 

years as quantitative milestone years: 


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176See State Air Quality Control Plan, Vol. II, 

section III.D.7.10.2. 

177 Id. 

178 Id. at section III.D.7.10.3.3, Table 7.10–5. 

179 Id. at section III.D.7.10.2. 

180 Id. 

181See 40 CFR 51.1013(a)(3)(ii) (‘‘At a minimum, 

each quantitative milestone plan must include a 

milestone for tracking progress achieved in 

implementing the SIP control measures by each 

milestone date.’’) (emphasis added). 

2023, 2026, and 2029.176 Alaska used 

emissions reductions achieved 

compared to projected emissions 

reductions as the metric to objectively 

evaluate progress toward attainment.177

Alaska calculated expected emissions 

reductions based on the control measure 

phase-in schedule.178 In its Quantitative 

Milestone Reports required by CAA 

section 189(c) and 40 CFR 51.1013(b), 

Alaska reported the emissions 

reductions achieved by the end of the 

milestone year compared to the 

projected emissions reductions included 

in the quantitative milestone provisions 

in the Fairbanks Revised 189(d) Plan, 

specifically, State Air Control Quality 

Plan, Vol. II, section III.D.7.10.3. Alaska 

made clear that the state will include in 

its QM reports completion statistics and 

phase-in percentages for each measure 

included in the Fairbanks Revised 

189(d) Plan.179

According to the Fairbanks Revised 

189(d) Plan, one of Alaska’s reasons for 

selecting emissions reductions achieved 

compared to projected emissions 

reductions as the objective metric is 

because doing so allows Alaska to take 

credit for emissions reductions from 

voluntary measures that are not part of 

its control strategy.180 Alaska provided 

the example of emissions reductions 

attributable to natural gas expansion. As 

discussed further below in section II.F.4 

of this preamble, the EPA disagrees with 

this specific rationale for allowing the 

state to take credit for emissions 

reductions from voluntary measures that 

are not part of its control strategy. 

4. The EPA’s Evaluation and Proposed 

Action Regarding the Quantitative 

Milestones 

The EPA is proposing to approve the 

Fairbanks Revised 189(d) Plan as 

meeting the quantitative milestone 

requirements of CAA section 189(c)(1) 

and 40 CFR 51.1013. First, in 

accordance with 40 CFR 

51.1013(a)(3)(ii) and (4), the Fairbanks 

Revised 189(d) Plan includes 

quantitative milestones for the years 

2023, 2026, and 2029. Second, the 

Fairbanks Revised 189(d) Plan includes 

phase-in metrics for each measure in the 

control strategy, including measures 

necessary to meet the BACM and BACT 

requirements in CAA section 189(b) and 

40 CFR 51.1010(a) and the requirements 

of CAA section 189(d) and 40 CFR 

51.1010(c). 

Finally, the measures allow for 

objective evaluation of RFP. As stated in 

the preceding paragraphs, the EPA 

interprets the CAA as allowing states to 

identify milestones that are suitable for 

the specific facts and circumstances of 

the attainment area. The EPA proposes 

to determine that Alaska’s quantitative 

milestones provide objective evaluation 

of RFP and are suitable for the specific 

facts and circumstances for the 

Fairbanks PM2.5 Nonattainment Area. 

Although the EPA agrees that comparing 

emissions reductions achieved to 

projected emissions reductions allows 

for objective evaluation of RFP for the 

Fairbanks PM2.5 Nonattainment Area, 

the EPA disagrees with Alaska’s stated 

rationale for selecting this metric. The 

purpose of QMs is to provide an 

objective evaluation of the state’s 

implementation of the SIP control 

measures.181 Therefore, crediting 

emissions reductions attributable to 

non-SIP measures toward achieving a 

QM is inconsistent with CAA section 

189(c) and 40 CFR 51.1013. 

Nevertheless, using emissions 

reductions as the metric is appropriate 

for the Fairbanks Revised 189(d) Plan 

because of the overlapping nature of 

control measures and associated 

emissions reductions, particularly those 

focused on the space heating area source 

sector. Specifically, the implementation 

of specific measures designed to reduce 

emissions from solid fuel-fired burning 

devices impacts nearly all other areasource controls measures. For example, 

the wood stove change out program 

removes wood stoves from the 

emissions inventory. This reduces direct 

PM2.5 emissions, but also impacts the 

emissions reductions achieved by the 

Solid Fuel-Burning Appliance 

Curtailment Program and dry wood 

requirements. 

Alaska could achieve more wood 

stove change-outs than it projects in a 

milestone year and, thus, achieve more 

emissions reductions attributable to that 

measure. However, that measure, by its 

nature, changes the makeup of the 

remaining wood stove users and their 

collective compliance with dry wood 

requirements and the curtailment 

program. Thus, there could be an 

instance where Alaska overperforms on 

one wood stove control measure, and 

that overperformance causes an 

underperformance on one or more other 

similar measures, but that collectively 

the measures achieve RFP. 

Relatedly, the wood stove change out 

program has the potential to moderate 

the benefits of measures designed to 

reduce SO2 emissions by increasing the 

number of residences using oil fuel-fired 

heating devices. Comparing emissions 

reductions achieved to projected 

emissions reductions as the milestone 

metric allows Alaska to take into 

consideration these complex 

interactions and ultimately provides a 

more meaningful assessment of whether 

Alaska’s plan is achieving RFP. 

In addition to the emissions reduction 

metric, the Fairbanks Revised 189(d) 

Plan includes several other objective 

metrics for RFP, including the number 

of wood stoves changed out, compliance 

percentage for tracking the progress of 

the solid-fuel burning device change out 

program, and percent implementation as 

metrics for the fuel sulfur content shift 

mandate, dry wood requirements, 

mandatory wood device removal, and 

more stringent no other adequate source 

of heat requirements. 

Alaska has demonstrated its ability to 

include emissions reduction statistics in 

its quantitative milestone reports. On 

March 29, 2024, Alaska submitted its 

quantitative milestone report for 

quantitative milestone year 2023 (‘‘2023 

QM Report’’). The EPA determined the 

2023 QM Report was adequate on 

November 14, 2024. Both the 2023 QM 

Report and the EPA’s adequacy 

determination are included in the 

docket for this action. 

The 2023 QM Report included a 

certification from the Governor’s 

designee that the control strategy in the 

Fairbanks Revised 189(d) Plan is being 

implemented consistent with the RFP 

provisions in the Fairbanks Revised 

189(d) Plan. The 2023 QM Report also 

included calculations and associated 

technical support for emissions 

reductions attributable to the measures 

in the control strategy. The report 

compared emissions reductions 

achieved to date to those projected 

based on the control measure phase-in 

schedule. The report also included, for 

example, the number of wood stoves 

changed out as of 2023 as well as the 

basis for implementation percentages 

and compliance rates for each control 

measure. Finally, the 2023 QM Report 

included a discussion as to whether the 

area will attain the PM2.5 NAAQS by 

2027. Therefore, the EPA proposes to 

approve the Fairbanks Revised 189(d) 

Plan as meeting the quantitative 

milestone requirements of CAA section 

189(c)(1) and 40 CFR 51.1013. 


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182 40 CFR 51.1014(a). 

183 81 FR 58010, August 24, 2016, at p. 58066; see 

also Addendum to the General Preamble for the 

Implementation of Title I of the Clean Air Act 

Amendments of 1990, 59 FR 41998, August 16, 

1994, at 42015 (‘‘General Preamble Addendum’’). 

184 81 FR 58010, August 24, 2016, at p. 58066; see 

also General Preamble at pp. 13512, 13543–13544, 

and General Preamble Addendum, at pp. 42014– 

42015. 

185 General Preamble, at p. 13511. 

186 ‘‘Guidance on the Preparation of State 

Implementation Plans Provisions that Address the 

Nonattainment Area Contingency Measure 

Requirements for Ozone and Particulate Matter,’’ 

Joseph Goffman, U.S. Environmental Protection 

Agency, Assistant Administrator, Office of Air and 

Radiation, December 3, 2024. 

187 81 FR 58010, August 24, 2016, at p. 58066; see 

also General Preamble, at pp. 13511, 13543–13544, 

and General Preamble Addendum, at pp. 42014– 

42015. 

188 81 FR 58010, August 24, 2016, at p. 58066. 

189 Id. at p. 58067. 

190Bahr v. EPA, 836 F.3d 1218, 1235–1237 (9th 

Cir. 2016). See also Sierra Club v. EPA, 21 F.4th 

815, 827–28 (D.C. Cir. 2021). 

191Assoc. of Irritated Residents v. EPA, 10 F.4th 

937, 946–47 (9th Cir. 2021) (‘‘AIR v. EPA’’ or 

‘‘AIR’’). 

G. Contingency Measures 

1. Statutory and Regulatory 

Requirements Regarding the 

Contingency Measures 

Under CAA section 172(c)(9), states 

required to make an attainment plan SIP 

submission must include contingency 

measures to be implemented if the area 

fails to meet RFP or fails to attain the 

NAAQS by the applicable attainment 

date. Under the PM2.5 SIP Requirements 

Rule, states must include contingency 

measures that the state will implement 

following a determination by the EPA 

that the state has failed: (1) to meet any 

RFP requirement in the approved SIP; 

(2) to meet any QM in the approved SIP; 

(3) to submit a required QM report; or 

(4) to attain the applicable PM2.5

NAAQS by the applicable attainment 

date.182

In accordance with the statute, 

contingency measures must be fully 

adopted rules or control measures that 

are ready to be implemented upon the 

EPA determination of a failure of any of 

the four types specified by statute and 

regulation for purposes of the PM2.5

NAAQS at issue.183 The contingency 

measures must be included in the state’s 

SIP and explicitly provide that they will 

take effect in the case of any such 

finding of failure, without further 

significant action by the State or the 

EPA. In general, the EPA expects all 

actions needed to effect full 

implementation of the measures to 

occur within 60 days after the EPA 

notifies the state of a failure to meet RFP 

or of a failure to attain.184 The EPA has 

historically recommended that the 

additional emissions reductions from 

the contingency measures should be 

achieved within a year of the triggering 

event.185 The EPA has recently revised 

its guidance concerning the period of 

time during which contingency 

measures should provide emissions 

reductions, and now recommends that it 

may be appropriate for contingency 

measures to achieve emissions 

reductions within two years under 

certain circumstances.186 The purpose 

of contingency measures is to continue 

progress toward attainment, as the state 

develops and submits, and the EPA acts 

on, a SIP submission to address the 

underlying deficiency. 

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 has 

historically recommended that 

contingency measures should provide 

for emissions reductions equivalent to 

approximately one year of reductions 

needed for RFP in the nonattainment 

area.187 For PM2.5 NAAQS SIP planning 

purposes, prior to issuing the recent 

contingency measure guidance, the EPA 

has recommended that RFP should be 

calculated as the overall level of 

reductions needed to demonstrate 

attainment divided by the number of 

years from the base year to the 

attainment year.188 As part of the 

attainment plan SIP submission, the 

EPA expects states to explain the 

amount of anticipated emissions 

reductions that the contingency 

measures will achieve. In the event that 

a state is unable to identify and adopt 

contingency measures that will provide 

for approximately one year’s worth of 

emissions reductions, then the EPA 

recommends that the state provide a 

reasoned justification why the smaller 

amount of emissions reductions is 

appropriate.189 As further described 

below, the EPA revised and updated its 

guidance concerning the amount of 

emissions reductions that contingency 

measures should achieve and expanded 

its recommendations concerning how 

states may justify having contingency 

measures that achieve fewer reductions, 

in light of recent court decisions and the 

changed factual circumstances. 

To satisfy the contingency measure 

requirements of 40 CFR 51.1014, the 

contingency measures adopted as part of 

a PM2.5 NAAQS attainment plan must 

consist of control measures for sources 

in the area that are not otherwise 

required to meet other attainment plan 

requirements (e.g., BACM or BACT 

requirements). By definition, 

contingency measures are measures that 

are over and above what a state must 

adopt and impose to meet RFP and to 

provide for attainment by the applicable 

attainment date. Contingency measures 

serve the purpose of providing 

additional emissions reductions during 

the period after a failure to meet RFP or 

failure to attain as the state prepares a 

new SIP submission to rectify the 

problem. Accordingly, contingency 

measures must provide such additional 

emissions reductions during an 

appropriate period and must specify the 

timeframe by which their requirements 

would become effective following any of 

the EPA determinations specified in 40 

CFR 51.1014(a). 

To comply with CAA section 

172(c)(9), contingency measures must be 

both conditional and prospective, so 

that they will go into effect and achieve 

emissions reductions only in the event 

of a future triggering event such as a 

failure to meet RFP or a failure to attain. 

In the 2016 Bahr v. EPA decision,190 the 

Ninth Circuit Court of Appeals held that 

CAA section 172(c)(9) does not allow 

EPA approval of already-implemented 

control measures as contingency 

measures. Thus, already-implemented 

measures cannot serve as contingency 

measures under CAA section 172(c)(9). 

For purposes of the PM2.5 NAAQS, a 

state must develop, adopt, and submit 

one or more contingency measures to be 

triggered upon a failure to meet any RFP 

requirement, failure to meet a 

quantitative milestone requirement, 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 or 

quantitative milestone requirements and 

beyond those predicted to achieve 

attainment of the NAAQS. 

In another recent decision concerning 

contingency measures for the ozone 

NAAQS, the Ninth Circuit Court of 

Appeals held that the surplus emissions 

reductions from already-implemented 

measures cannot be relied upon to 

justify the approval of a contingency 

measure that would achieve far less 

than one year’s worth of RFP as 

sufficient by itself to meet the 

contingency measure requirements of 

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

the nonattainment area.191

a. Revised Contingency Measure 

Guidance 

On December 3, 2024, the EPA issued 

new guidance addressing the 

contingency measures requirement of 

CAA section 172(c)(9), herein referred to 

as the ‘‘Contingency Measure 


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1624 Federal Register / Vol. 90, No. 5 / Wednesday, January 8, 2025 / Proposed Rules 

192 ‘‘Guidance on the Preparation of State 

Implementation Plans Provisions that Address the 

Nonattainment Area Contingency Measure 

Requirements for Ozone and Particulate Matter,’’ 

Joseph Goffman, U.S. Environmental Protection 

Agency, Assistant Administrator, Office of Air and 

Radiation, December 3, 2024. 

193See 81 FR 58010, Aug. 24, 2016, at p. 58067. 

194Contingency Measure Guidance, at p. 23. 

195Contingency Measure Guidance, at p. 46 

196 Id. 

197See 81 FR 58010, Aug. 24, 2016, at p. 58067. 

198Contingency Measure Guidance, at p. 33. 

199 Id. 

200Contingency Measure Guidance, at p. 34. 

201 85 FR 54509, September 2, 2020, at pp. 54509– 

10. 

202 ‘‘Contingency measures in nonattainment and 

maintenance areas identified in 18 AAC 50.015(b), 

Guidance.’’192 The principal differences 

between the latest Contingency Measure 

Guidance and prior guidance on 

contingency measures relate to the 

EPA’s recommendations concerning the 

specific amount of emissions reductions 

that implementation of contingency 

measures should achieve and to the 

timing for when the emissions 

reductions from the contingency 

measures should occur. The 

Contingency Measure Guidance also 

provides recommended procedures for 

developing a demonstration, if 

applicable, that the area lacks sufficient 

feasible measures to achieve one year’s 

worth of reductions, building on 

existing guidance that the state may 

provide a reasoned justification why the 

smaller amount of emissions reductions 

is appropriate.193

The EPA has historically 

recommended that contingency 

measures should achieve approximately 

one year’s worth of RFP, calculated 

based upon the initial emissions 

inventory of the attainment plan for the 

area in question. As explained in the 

updated guidance, however, the EPA is 

revising its interpretation of the 

requirements of CAA section 172(c)(9). 

Under the Contingency Measure 

Guidance, the EPA recommends that the 

amount of emissions reductions that 

contingency measures should achieve 

should be one year’s worth of 

‘‘progress,’’ as opposed to one year’s 

worth of RFP.194 One year’s worth of 

‘‘progress’’ is calculated by determining 

the average annual reductions between 

the base year emissions inventory and 

the projected attainment year emissions 

inventory, determining what percentage 

of the base year emissions inventory this 

amount represents, then applying that 

percentage to the projected attainment 

year emissions inventory to determine 

the amount of reductions appropriate 

from contingency measures to ensure 

ongoing progress if the measures are 

triggered. 

With respect to the time period that 

reductions from contingency measures 

should occur, the EPA previously 

recommended that contingency 

measures take effect within 60 days of 

being triggered, and that the resulting 

emissions reductions generally occur 

within one year of the triggering event. 

Under the Contingency Measure 

Guidance, in instances where there are 

insufficient contingency measures 

available to achieve the recommended 

amount of emissions reductions within 

one year of the triggering event, the EPA 

is recommending that contingency 

measures that provide reductions within 

two years of the triggering event would 

be appropriate to consider towards 

achieving the recommended amount of 

emissions reductions.195 The 

Contingency Measure Guidance does 

not alter the 60-day recommendation for 

the contingency measures to take initial 

effect.196

If, after adequately evaluating 

additional control measures, the state is 

unable to identify contingency measures 

that would provide a sufficient amount 

of emissions reductions, the EPA 

recommends that the state provide an 

analysis to establish that there are no 

additional feasible contingency 

measures. The EPA has recommended 

this approach for attainment plans for 

the PM2.5 NAAQS since promulgating 

the PM2.5 SIP Requirements Rule.197 In 

the Contingency Measure Guidance, the 

EPA provides additional guidance to 

states for establishing that there are no 

additional feasible contingency 

measures. The EPA recommends that 

the state should provide a reasoned 

justification that explains and 

documents how it has evaluated all 

existing and potential control measures 

relevant to the appropriate source 

categories and pollutants in the 

nonattainment area, and has reached 

reasonable conclusions regarding 

whether such measures are feasible as 

contingency measures.198

As explained in the Contingency 

Measure Guidance, while the EPA notes 

that CAA section 172(c)(9) and section 

182(c)(9) do not explicitly provide for 

consideration of whether specific 

measures are feasible, the Agency 

believes that the best reading of these 

provisions is that they do not require 

states to adopt contingency measures 

regardless of any technological or cost 

constraints whatsoever.199 Thus, the 

EPA views the contingency measure 

requirements as not to require air 

agencies to adopt and impose infeasible 

measures. The statutory provisions 

applicable to other nonattainment area 

plan control measure requirements, 

including RACM/RACT (for ozone and 

PM), BACM/BACT (for PM), and MSM 

(for PM), allow air agencies to exclude 

certain control measures that are 

deemed unreasonable or infeasible 

(depending on the requirement). For 

example, the MSM provision in CAA 

section 188(e) requires plans to include 

‘‘the most stringent measures that are 

included in the implementation plan of 

any state or are achieved in practice in 

any state, and can feasibly be 

implemented in the area.’’ The EPA 

concludes that Congress similarly did 

not expect air agencies to satisfy the 

contingency measure requirement with 

infeasible measures. Thus, the EPA 

anticipates that a demonstrated lack of 

feasible measures would be a reasoned 

justification for adopting contingency 

measures that only achieve a lesser 

amount of emissions reductions.200

2. Summary of the EPA’s Prior Action 

Regarding the Contingency Measures 

In the Fairbanks Serious Plan, Alaska 

submitted revisions to 18 AAC 

50.077(n) that included two contingency 

measures purporting to meet the 

requirements of CAA section 172(c)(9) 

and 40 CFR 51.1014. The first measure 

requires owners of older EPA-certified 

wood fired heating devices with an 

emission rating above 2.0 grams per 

hour (g/hr), manufactured 25 years prior 

to the effective date of an EPA finding 

that triggers this measure, to remove the 

device upon the sale of a property or by 

December 31, 2024, whichever is earlier. 

The second measure requires owners of 

EPA-certified devices that were 

manufactured less than 25 years prior to 

the EPA finding to remove the device 

prior to reaching 25 years from the date 

of manufacture. On September 24, 2021, 

the EPA approved the submitted 

revisions to 18 AAC 50.077(n) as SIPstrengthening, but otherwise did not 

determine whether the revisions 

satisfied the contingency measure 

requirement of CAA section 172(c)(9) 

and 40 CFR 51.1014. 

On September 2, 2020, the EPA issued 

a determination that the Fairbanks PM2.5

Nonattainment Area failed to attain the 

2006 24-hour NAAQS by the Serious 

area attainment date.201 This action 

triggered the contingency measures 

included in the Fairbanks Serious Plan 

at 18 AAC 50.077(n). 

In the initial Fairbanks 189(d) Plan, 

Alaska: (1) retained the revisions to 18 

AAC 50.077(n); (2) submitted a revision 

to state regulations at 18 AAC 50.030(c), 

to act as a central trigger mechanism for 

all contingency measures contained in 

Alaska’s nonattainment plans,202 and (3) 


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(d), and (e) must be implemented as described in 

the State Air Quality Control Plan for an area 

upon. . .the effective date of an EPA finding that 

the area failed (i) to attain the applicable NAAQS 

by the applicable attainment date; (ii) to meet a 

quantitative milestone; (iii) to submit a required 

quantitative milestone report; or (iv) to meet a 

reasonable further progress requirement.’’ 

203State Air Quality Control Plan, Vol. II, section 

III.D.7.11.2.1 (adopted November 5, 2024). 

204 Id. at section III.D.7.10, Table 7.10–8. 205 Id. at section III.D.7.11.2.2. 206 Id. at section III.D.7.11.3.3.8. 207 Id. at section III.D.7.11.3.3.1.1. 208 Id. at section III.D.7.11.3.3.1 209 Id. at section III.D.7.11.3.3.1.3. According to 

the Fairbanks Revised 189(d) Plan, requiring 

residents to repair their fuel oil boilers would 

achieve at most 0.001 tons per day of SO2 emissions 

reductions. Requiring replacement of fuel oil boilers 

would achieve at most 0.006 tons per day of SO2

emissions reductions. 

210 Id. at section III.D.7.11.3.3. 

211 Id. at section III.D.7.11.3.3.3. 

212 Id. 

213 Id. 

214 Id. at section III.D.7.11.3.3.2. 

215 Id. 

216 Id. at section III.D.7.11.3.3.5. 

217 18 AAC 50.076(g). 

included an additional contingency 

measure, as a revision to State Air 

Quality Control Plan, Vol. II, section 

III.D.7.12 (Fairbanks Emergency Episode 

Plan) that, if triggered, lowers the wood 

stove curtailment Stage 2 alert threshold 

from 30 mg/m3 to 25 mg/m3. 

On January 10, 2023, the EPA 

approved the submitted revisions to 18 

AAC 50.030(c) as consistent with the 

triggering events in 40 CFR 51.1014. The 

EPA also approved as SIP-strengthening 

the submitted revisions to the Fairbanks 

Emergency Episode Plan regarding the 

wood stove curtailment thresholds. 

However, the EPA determined that the 

revisions to 18 AAC 50.077(n) did not 

meet contingency measures 

requirements because they were already 

triggered and implemented. 

With respect to the revision in the 

Fairbanks Emergency Episode Plan, the 

EPA determined that this measure alone 

is insufficient to meet contingency 

measures requirements, and Alaska did 

not provide a reasoned justification for 

why the state could not adopt additional 

contingency measures. Thus, the EPA 

disapproved the Fairbanks Serious Plan 

and initial Fairbanks 189(d) Plan with 

respect to the contingency measures 

element. The State is addressing this 

prior disapproval for the contingency 

measures element by submitting new 

provisions intended to meet the 

requirement in the Fairbanks Revised 

189(d) Plan. 

3. Summary of the State’s Submission 

Regarding the Contingency Measures 

In the Fairbanks Revised 189(d) Plan, 

Alaska includes: (1) calculations of one 

year’s worth of progress and RFP 

metrics; (2) an evaluation of potential 

contingency measures; (3) three 

contingency measures purporting to 

meet the requirements of CAA section 

172(c)(9) and 40 CFR 51.1014; and (4) 

an evaluation of whether the 

contingency measures achieve sufficient 

emissions reductions. 

a. Alaska’s Calculation of One Year’s 

Worth of Progress 

Alaska used the one year’s worth of 

progress metric to demonstrate that its 

contingency measures achieve sufficient 

emissions reductions.203 According to 

the Fairbanks Revised 189(d) Plan, the 

one year’s worth of progress target is 

0.102 tons per episode day for direct 

PM2.5 emissions and 0.115 tons per 

episode day for SO2 emissions. Alaska 

also calculated the one year’s worth of 

RFP target for direct PM2.5 and SO2 as 

0.172 tons per episode day and 0.122 

tons per episode day, respectively.204

b. Alaska’s Identification and Evaluation 

of Contingency Measures 

Alaska evaluated 25 potential 

measures as contingency measures.205

Alaska evaluated measures to reduce 

SO2 emissions and direct PM2.5

emissions. Alaska determined that there 

were no NH3 control measures that 

could serve as contingency measures.206

With respect to SO2 emissions, Alaska 

evaluated requiring the use of ULSD 

heating oil (i.e., a 15 parts per million 

sulfur content fuel oil requirement). 

According to Alaska, the ULSD mandate 

would significantly reduce SO2

emissions from the residential space 

heating source category. However, 

Alaska determined that the ULSD 

mandate could not achieve emissions 

reductions until year three of 

implementation and also posed 

technological feasibility concerns.207

Alaska also identified major 

stationary source SO2 controls, aircraft 

SO2 controls, residential fuel oil boilers 

repair and replacement requirements as 

potential measures. Alaska determined 

that, based on the major stationary 

source SO2 precursor demonstration, 

SO2 controls on these sources would 

achieve negligible reductions in sulfate 

formation in the nonattainment area.208

Similarly, Alaska determined that 

requiring residents to replace or upgrade 

their fuel oil boilers would result in 

negligible SO2 emissions reductions.209

With respect to aircraft, Alaska 

explained that the State does not have 

authority to regulate fuel sulfur content 

for commercial aircraft. Thus, Alaska 

determined that there were no 

technologically feasible contingency 

measures for SO2. 

Alaska also evaluated several 

potential contingency measures 

designed to reduce emissions of direct 

PM2.5. Specifically, Alaska evaluated 

enhancements to the existing 

curtailment program, enhancements to 

the existing wood device removal 

program, used oil burning restrictions, 

vehicle idling restrictions, making 

existing control measures more 

stringent, and various economic 

incentive programs suggested by 

commenters.210 Alaska ultimately 

determined that enhancing the existing 

curtailment program and existing wood 

device removal program were the only 

technologically feasible measures that 

would achieve more than negligible 

emissions reductions. 

Alaska determined that prohibiting 

small ‘‘pot burners’’ and used oil 

burners would achieve negligible 

emissions reductions.211 According to 

the Fairbanks Revised 189(d) Plan, 

prohibiting small pot burners would 

achieve emissions reductions of 0.002 

tons per episode day of direct PM2.5.212

Likewise, prohibiting used oil burners 

would achieve less than 0.0001 tons per 

episode day of direct PM2.5 emissions 

reductions.213 Similarly, Alaska 

determined that imposing vehicle idling 

restrictions would achieve 0.002 tons 

per episode day of direct PM2.5

emissions reductions. 

Alaska also evaluated adopting a 1.0 

grams per hour PM emissions standard 

for new solid fuel-fired heating devices, 

similar to the measure implemented by 

Missoula, Montana.214 Alaska 

determined that this measure would 

achieve emissions reductions through 

attrition (phase-out of old stoves) and 

would not achieve significant emissions 

reductions in the aggregate given 

Alaska’s already stringent restrictions 

on new wood stoves.215 Alaska also 

noted that the measure effectively 

restricts new solid-fuel burning devices 

to pellet-fuel fired stoves. Alaska 

explained that pellet stoves require 

electricity to operate. According to 

Alaska, Fairbanks experiences frequent 

power outages during the winter months 

and residents must have a reliable 

source of heat during these periods. 

According to Alaska, this renders the 

measure technologically infeasible as a 

contingency measure. 

In addition, Alaska evaluated 

reducing the allowable moisture content 

in commercial dry wood.216 Under 

Alaska’s current regulations, all 

commercial dry wood must have a 

moisture content of 20 percent or 

less.217 Alaska determined that reducing 

the moisture content percentage to 15 


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218State Air Quality Control Plan, Vol. II, section 

III.D.7.11.3.3.5. 

219 Id. at section III.D.7.11.3.3.6; Id. at section 

III.D.7.11.3.3.4. 

220 Id. 

221 Id. at section III.D.7.11.3.3.6. 

222 Id. at section III.D.7.11.3.3.7. 

223 Id. 

224 Id. 

225 18 AAC 50.075(e); State Air Quality Control 

Plan, Vol. II, section III.D.7.11.4. 

226 Id. 

227 Id. 

228State Air Quality Control Plan, Vol. II, section 

III.D.7.12.2. 

229 Id. See also State Air Quality Control Plan, 

Vol. II, section III.D.7.12, Table 7.12–1. 

230State Air Quality Control Plan, Vol. II, section 

III.D.7.11.3.1. 

231 18 AAC 50.075(e); State Air Quality Control 

Plan, Vol. II, section III.D.7.12. See State Air Quality 

Control Plan, Vol. II, section III.D.7.11.4.3. 

232State Air Quality Control Plan, Vol. II, section 

III.D.7.11.4.1. 

233 Id.; See also State Air Quality Control Plan, 

Vol. II, section III.D.7.10.3.2. 

234 Id. at section III.D.7.11.4.1. 

235 Id. at section III.D.7.11.4.3. 

236 Id. 

237 Id. 

238 Id. at section III.D.7.11.4.2. 

239 Id. at section III.D.7.11.4.3. 

240 Id. 

would reduce PM2.5 emissions by 0.011 

tons per episode day, while reducing 

the moisture percentage to 10 would 

reduce PM2.5 emissions by 0.022 tons 

per episode day. However, Alaska 

determined that achieving these 

emissions reductions within two years 

of a triggering event is not 

technologically feasible due to 

infrastructure constraints.218 According 

to Alaska, there is a single dry wood 

kiln in Fairbanks that supplies 31 

percent of the commercial dry wood in 

the area. Requiring the kiln to achieve 

lower wood moisture content would 

require longer dry times, which would 

restrict the availability of dry wood in 

the area unless the kiln expanded 

capacity. 

Alaska also evaluated granting 

citation authority to the Alaska 

Department of Environmental 

Conservation and increasing civil 

penalties for SIP violations as potential 

contingency measures.219 Alaska 

determined that neither measure would 

improve compliance or achieve 

emissions reductions.220 Alaska 

explained that it has broad and efficient 

state judicial authority to enforce 

violations of the SIP. Alaska included a 

discussion of its process for enforcing 

SIP violations. Alaska also explained 

that its civil penalty authority under 

Alaska Statute 46.03.760(e) does not set 

a maximum penalty for SIP 

violations.221

Finally, Alaska evaluated whether 

several economic incentive programs 

suggested by commenters could satisfy 

contingency measure requirements.222

These included subsidizing the cost of 

ULSD, subsidizing natural gas, and 

various electricity cost subsidy 

programs.223 Alaska determined that 

each of these programs would not be 

enforceable contingency measures. 

Alaska also noted that implementing the 

programs would require more than 

minimal further effort on the part of the 

state.224 Therefore, Alaska concluded 

that these economic incentive programs 

would not meet the legal requirements 

for contingency measures. 

c. Alaska’s Contingency Measures 

Included in the Fairbanks Revised 

189(d) Plan 

Based on the analysis discussed in the 

preceding paragraphs, Alaska concluded 

that the only technologically feasible 

contingency measures were enhancing 

the solid fuel burning device 

curtailment and removal programs. 

Therefore, in the Fairbanks Revised 

189(d) Plan, the State includes three 

measures intended to meet the 

contingency measures requirements: (1) 

lower alert levels under the Solid FuelBurning Appliance Curtailment 

Program; (2) an enforceable commitment 

to increase the staff hours dedicated to 

implementing the Solid Fuel-Burning 

Appliance Curtailment Program; and (3) 

an enforceable commitment to increase 

staff hours dedicated to compliance and 

enforcement with the state regulations 

requiring replacement of older wood 

stoves by December 31, 2024.225

Alaska’s current EPA-approved Solid 

Fuel-Burning Appliance Curtailment 

Program includes two stages. Alaska 

calls a Stage 1 burn ban when Alaska 

projects ambient PM2.5 concentrations to 

be at or above 20 mg/m3. Under a Stage 

1 burn ban, individuals may only 

operate their solid fuel-burning device if 

the individual has an Alaska-approved 

‘‘no other adequate source of heat’’ 

(NOASH) waiver or an Alaska-approved 

solid fuel-burning device that meets 

specific stage 1 waiver age and emission 

rate criteria.226 Under the current 

curtailment program, Alaska calls a 

Stage 2 burn ban when the state projects 

ambient PM2.5 concentrations to exceed 

30 mg/m3. Under a Stage 2 burn ban, 

individuals may only operate their solid 

fuel burning device if they have an 

Alaska-approved NOASH waiver.227

As the first intended contingency 

measure, the State adopted revisions to 

the Fairbanks Emergency Episode Plan 

that would reduce the alert levels under 

the Solid Fuel-Burning Appliance 

Curtailment Program.228 Upon a 

triggering event, such as failure to attain 

or failure to meet a QM, the Stage 1 alert 

level will be lowered to 15 mg/m3 and 

the Stage 2 alert level will be lowered 

to 20 mg/m3.229 The State anticipates 

that lowering these alert levels would 

result in Alaska calling burn bans more 

frequently and for longer durations, thus 

lowering the emissions from the solid 

fuel burning device source category.230

Alaska projected this first contingency 

measure will result in emissions 

reductions of 0.086 tons per day PM2.5

but increase SO2 emissions by 0.047 

tons per day. 

As a second intended contingency 

measure in the Fairbanks Revised 189(d) 

Plan, the State submitted an enforceable 

commitment to increase the Alaska 

Department of Environmental 

Conservation staff hours dedicated to 

the compliance and enforcement of the 

Solid Fuel-Burning Appliance 

Curtailment Program to 2,800 hours per 

year, within 60 days of any triggering 

event.231 This would be an increase 

from the current 2,200 hours per 

year.232 Under the current allocation of 

staff hours, Alaska achieved 38 percent 

compliance with the curtailment 

program.233 Alaska projected that with 

the additional staff hours, the 

compliance rate would increase to 65 

percent.234 Alaska committed to 

maintain the increased allocation of 

staff hours, unless or until the state 

could later relax the measure through a 

SIP revision.235 Alaska further 

committed to publishing an annual 

report that includes the staff hours 

dedicated to compliance and 

enforcement of the Solid Fuel-Burning 

Appliance Curtailment Program and the 

results of the Alaska Department of 

Environmental Conservation’s annual 

assessments of the compliance rate.236

As the third intended contingency 

measure, the State submitted a second 

enforceable commitment to dedicate 300 

staff hours to compliance and 

enforcement with the SIP-approved 

rules requiring replacement of older 

wood stoves (18 AAC 50.077(l–n)).237

Alaska projects this staffing level would 

increase the compliance rate from 30 

percent to 45 percent.238 Alaska 

committed to maintaining the allocation 

of staffing hours unless or until the state 

can relax the measure through a SIP 

revision.239 Alaska further committed to 

publishing an annual report that 

includes the staff hours dedicated to 

compliance and enforcement with the 

regulations mandating replacement of 

older wood stoves.240


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241 Id. at section III.D.7.11.2.1. 

242 Id. 

243 Id. 

244 Id. 

245 Id. at section III.D.7.10, Table 7.10–8. 

246 Id. at section III.D.7.10.3.4. 

247 Jentgen, Matthew. (December 4, 2024). 

Contingency Measure assessment of available 

control measures in the Fairbanks Revised 189(d) 

Plan. U.S. Environmental Protection Agency, 

Region 10, Air and Radiation Division, EPA–R10– 

OAR–2024–0595. 

248 88 FR 84626, December 5, 2023, at p. 84635. 

249 88 FR 84626, December 5, 2023, at p. 84636. 

250 Id. at pp. 84,638–49. 

d. Emissions Reductions From Alaska’s 

Contingency Measures 

Alaska projected that these three 

contingency measures would achieve 

emissions reductions of 0.151 tons per 

episode day of direct PM2.5 emissions 

(0.142 tons per day when accounting for 

some overlap) and increase SO2

emissions by 0.038 tons per episode 

day. As stated in the preceding 

paragraphs, Alaska proposed to use the 

one year’s worth of progress metric for 

contingency measures. According to the 

Fairbanks Revised 189(d) Plan, the one 

year’s worth of progress target is 0.102 

tons per episode day for direct PM2.5

and 0.115 tons per episode day for SO2. 

Alaska purported to justify the 

increase in SO2 emissions with the 

surplus emissions reductions of direct 

PM2.5 emissions through ‘‘interpollutant trading.’’ 241 Alaska developed 

a 5:1 ratio to compare reductions of 

direct PM2.5 emissions to reductions of 

SO2 emissions. For the purposes of 

developing the ratio, Alaska 

conservatively estimated that SO2

emissions contribute 20 percent of 

ambient PM2.5 levels in the area.242

Thus, Alaska calculated that achieving 

an additional 0.023 tons per episode day 

(0.125 tons per episode day total) of 

direct PM2.5 emissions would achieve 

the required one year’s worth of 

attainment for both direct PM2.5 and SO2

emissions.243 Because Alaska’s 

contingency measures would achieve 

0.151 tons per episode day of direct 

PM2.5 emissions, Alaska stated that its 

contingency measures would achieve 

sufficient emissions reductions.244

Alaska also compared the projected 

emissions reductions from its 

contingency measures to the one year’s 

worth of RFP metric. Alaska calculated 

that the one year’s worth of RFP target 

for direct PM2.5 and SO2 emissions as 

0.172 tons per episode day and 0.122 

tons per episode day respectively.245

The State acknowledged that its 

contingency measures would not 

achieve emissions reductions equivalent 

to one year’s worth of RFP even taking 

into consideration inter-pollutant 

trading.246

4. The EPA’s Evaluation and Proposed 

Action 

The EPA has reviewed the three 

measures that the State included in the 

Fairbanks Revised 189(d) Plan to meet 

the contingency measures requirement 

for the 2006 24-hour PM2.5 NAAQS. For 

the reasons explained in the following 

sections and the accompanying TSD, the 

EPA: (i) proposes to approve one of the 

State’s submitted measures as a 

contingency measure; (ii) proposes to 

approve the other two measures as SIPstrengthening; (iii) proposes to find that 

the State has provided an adequate 

reasoned justification that no other 

contingency measures are feasible; and 

(iv) proposes to approve the Fairbanks 

Revised 189(d) Plan as meeting the 

contingency measure requirements in 

CAA Section 179(c)(9) and 40 CFR 

51.1014(a). 

a. Alaska’s Calculation of One Year’s 

Worth of Progress 

Alaska proposed to use the one year’s 

worth of progress metric to measure the 

sufficiency of its contingency measures. 

The EPA proposes to determine this is 

an appropriate metric. As discussed 

above, CAA section 172(c)(9) does not 

specify the amount of emissions 

reductions contingency measures must 

achieve. The EPA’s recent revised 

guidance explains its view that one 

year’s worth of progress approach is 

consistent with the primary objective of 

attaining the NAAQS. 

This approach takes into account the 

declining emissions inventories 

between the base year and attainment 

year. The EPA expects that Alaska’s 

control strategy in the Fairbanks 

Revised 189(d) Plan will achieve 

projected emissions reductions prior to 

any triggering event. Specifically, public 

participation in the wood stove change 

out program should continue given the 

mandatory change out requirements in 

18 AAC 50.077(l)–(n), along with the 

EPA grant funding through the Targeted 

Airshed Grant program. Moreover, the 

continued phase-in of diesel no. 1 fuel 

oil in place of diesel no. 2 fuel oil will 

reduce SO2 emissions. 

b. Alaska’s Identification and Evaluation 

of Contingency Measures 

As summarized in section II.G.3 of 

this preamble, Alaska evaluated several 

control measures that could serve as 

contingency measures to reduce 

emissions of the relevant pollutants 

from the relevant sources. The EPA has 

reviewed the State’s identification and 

evaluation of potential contingency 

measures. The EPA’s detailed review is 

included in a Technical Support 

Document included in the docket for 

this action.247 For the reasons stated in 

the following paragraphs, as well as in 

the Technical Support Document, the 

EPA is proposing to determine that 

Alaska adequately identified and 

evaluated potential contingency 

measures. 

In a prior action, the EPA approved 

comprehensive NOX and VOC precursor 

demonstrations submitted by Alaska. 

Therefore, these are not regulatory 

pollutants for purposes of the 2006 24- 

hour PM2.5 NAAQS in the Fairbanks 

PM2.5 Nonattainment Area. Accordingly, 

the State is not required to evaluate and 

adopt contingency measures for these 

pollutants.248 In this action, the EPA is 

proposing to approve an SO2 precursor 

demonstration for major stationary 

sources. If the EPA finalizes an approval 

of this precursor demonstration, then 

stationary sources that emit SO2 will not 

be subject to BACM/BACT. 

Accordingly, the State would not be 

required to evaluate and adopt 

contingency measures for SO2 emissions 

from such sources, but Alaska would 

still be required to evaluate and adopt 

SO2 emissions controls from other area 

and mobile sources. 

With respect to NH3, the EPA has 

previously approved Alaska’s 

determination that there are no NH3

controls for major stationary sources in 

the nonattainment area.249 The EPA also 

previously approved as BACM for NH3

Alaska’s suite of controls for direct 

PM2.5 on area sources.250 The EPA 

agrees with Alaska’s determination that 

there are no additional NH3 controls 

that could serve as potential 

contingency measures. 

Alaska focused its evaluation of 

potential contingency measures on 

measures that could reduce direct PM2.5

emissions and SO2 emissions from areas 

sources and mobile sources. The EPA is 

proposing to approve the State’s 

approach to identifying and adopting 

potential contingency measures for 

these specific pollutants and sources as 

part of its proposed approval of the 

contingency measures element of the 

Fairbanks Revised 189(d) Plan. 

With respect to contingency measures 

to reduce SO2 emissions, the EPA 

proposes to approve Alaska’s 

determinations that (1) mandating ULSD 

is not technologically feasible as a 

contingency measure because it would 

not achieve emissions reductions within 

two years of being triggered; (2) 

requiring residents to repair or replace 

their fuel oil boilers would achieve 


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251State Air Quality Control Plan, Vol. II, section 

III.D.7.11.3.3.1.1. 

252 Id. 

253 42 U.S.C. 7573. 254 88 FR 84626, December 5, 2023, at p. 84664. 

255State Air Quality Control Plan, Vol. II, section 

III.D.7.11.3.3.5. 

negligible emissions reductions; and (3) 

regulating aircraft emissions is not 

viable as a contingency measure because 

of limitations on legal authority. 

Regarding mandating ULSD, the EPA 

agrees with the State that, if 

implemented, such a contingency 

measure could reduce SO2 emissions 

from the residential home heating 

source category, which is the dominant 

contributor to sulfate formation in the 

nonattainment area. However, the EPA 

agrees with Alaska’s determination that 

mandating USLD would not achieve 

emissions reductions until at least three 

years following the triggering event.251

This is due to the need to improve 

storage and distribution infrastructure 

in the area, the need to allow the 

distribution market to shift to new 

demands, and the time needed to phase 

out higher-sulfur fuels from existing 

storage vessels in the area.252 A 

contingency measure that required the 

use of ULSD fuel factually could not be 

implemented quickly following a 

triggering event, or achieve emissions 

reductions until several years following 

the triggering event. Thus, mandating 

ULSD as a contingency measure would 

not satisfy the key purpose of 

contingency measures of continuing 

progress towards attainment between 

the triggering event and submission of a 

revised plan. Based upon this analysis, 

the EPA agrees that a measure 

mandating sale and use of ULSD fuel in 

the Fairbanks PM2.5 Nonattainment Area 

is not viable as a contingency measure 

because of the time it would take to 

achieve emissions reductions. 

In addition, the EPA has reviewed 

Alaska’s emissions reductions 

calculations, including for the fuel oil 

boiler measures, and determined 

Alaska’s methodology is reasonable. 

Based on these calculations, the fuel oil 

boiler measures would achieve 

negligible emissions reductions. 

Regarding emissions from aircraft, states 

are prohibited under CAA section 233 

from adopting more stringent standards 

than those set by the Federal 

Government.253 Therefore, the EPA 

agrees that none of these potential 

measures are viable as contingency 

measures. 

Regarding potential contingency 

measures to control direct PM2.5

emissions, the EPA proposes to approve 

Alaska’s determinations of: (1) measures 

that would only achieve negligible 

emissions reductions; (2) measures that 

are technologically infeasible as 

contingency measures because they 

would not achieve emissions reductions 

within two years of being triggered; and 

(3) other measures that are 

technologically infeasible due to 

infrastructure constraints and local 

conditions. The EPA agrees that 

prohibiting operation and sale of small 

pot burners, used oil burners, and 

restricting vehicle idling would achieve 

negligible emissions reductions. The 

EPA also agrees that granting citation 

authority to the Alaska Department of 

Environmental Conservation and 

increasing state penalties for SIP 

requirement violations would have 

negligible emissions benefits as a 

contingency measure. 

The EPA also reviewed Alaska’s 

evaluation of a potential requirement 

that all new solid fuel-burning devices 

meet a 1.0 gram per hour PM2.5

emissions standard as a potential 

contingency measure. The EPA agrees 

that, in practice, the only wood heaters 

that can achieve this standard are pelletfuel fired stoves and certain highly 

controlled cordwood stoves. The EPA 

also notes that, this measure has the 

potential to reduce direct PM2.5

emissions from the solid fuel-burning 

source category. However, the EPA 

agrees with Alaska’s assessment that 

this requirement would necessarily be 

an attrition-based measure that only 

achieves emissions reductions as 

homeowners replace older stoves. In its 

prior action on the Fairbanks Serious 

Plan, the EPA disapproved a similar 

Alaska contingency measure mandating 

the removal of older certified wood 

stoves, in part because the measure 

would have achieved virtually no 

emissions reductions in the first year of 

implementation.254

In addition, the EPA agrees that this 

measure is technologically infeasible as 

a contingency measure. In particular, as 

Alaska states in the Fairbanks Revised 

189(d) Plan, pellet stoves require 

electricity to function, whereas 

cordwood stoves do not, and Fairbanks 

experiences power outages during the 

winter months. The EPA agrees that 

given the extremely cold temperatures 

residents experience, having a source of 

heat that does not rely on electricity 

remains a necessity. Based upon this 

analysis, the EPA agrees that a measure 

mandating that all new solid fuelburning devices meet a 1.0 gram per 

hour PM2.5 emissions standard in the 

Fairbanks area is not viable as a 

contingency measure because emissions 

reductions could not be achieved within 

two years and the measure is otherwise 

technologically infeasible. 

Regarding reducing the required 

moisture content for dry cordwood, the 

EPA notes that this measure has the 

potential to reduce emissions of direct 

PM2.5. Alaska estimated that a measure 

requiring all dry wood to meet a 10 

percent moisture content would reduce 

PM2.5 emissions by 0.022 tons per 

episode day, which equates to 18 

percent of one’s years-worth of 

progress.255 However, the EPA agrees 

with Alaska’s assessment that 

mandating a reduction in moisture 

content as a contingency measure would 

not be technologically feasible given the 

constraint on the dry wood supply in 

Fairbanks. In order to further reduce the 

moisture content of cordwood while 

satisfying consumer demand for 

commercial dry wood, additional kilns 

would need to be built in the Fairbanks 

area. This type of large capital project is 

unlikely to be accomplished quickly 

such that dry wood at less than 10 

percent moisture content could be 

reliably supplied to residents to achieve 

emissions reductions within two years 

of a triggering event. 

Therefore, the EPA proposes to 

determine that, to the extent the 

contingency measures in the Fairbanks 

Revised 189(d) Plan fall short of the 

emissions reductions necessary for one 

year’s worth of attainment, Alaska has 

provided an adequate reasoned 

justification for not adopting additional 

measures as contingency measures. 

c. Evaluation of Submitted Contingency 

Measures 

i. Lowered Alert Levels 

The submitted contingency measure 

lowering the alert levels for the Solid 

Fuel-Burning Appliance Curtailment 

Program is subject to Alaska’s regulation 

at 18 AAC 50.030(c) that is consistent 

with the triggers in 40 CFR 51.1014(a). 

The measure is thus conditional and 

prospective, as required by statute. This 

measure will take effect with minimal 

further effort from the State or the EPA. 

Neither Alaska nor the EPA will need to 

engage in any additional rulemaking or 

other significant action to implement 

the measure. Alaska already issues 

alerts through its preexisting program 

approved into the SIP. Thus, 

implementing the contingency measure 

will be ministerial, in terms of adjusting 

the curtailment alert thresholds. 

At the time of adoption and 

submission to the EPA, these 

contingency measure alert levels are not 

otherwise included in the control 

strategy to meet any other attainment 

plan requirements. This measure 


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256Applying Alaska’s interpollutant trading 

mechanism, the combined emissions reductions for 

PM2.5 and SO2 are estimated to be 0.077 tons per 

day, representing 62 percent of the one year’s of 

interpollutant emissions reductions for PM2.5 and 

SO2. See State Air Quality Control Plan, Vol. II, 

section III.D.7.11.5.2; see also State Air Quality 

Control Plan, Vol. II, section III.D.7.11, Table 7.11– 

6. 

257See Comm. for a Better Arvin v. EPA, 786 F.3d 

1169, 1181 (9th Cir. 2015). 

258See 75 FR 74518, November 30, 2010, at pp. 

74535–56; see also BCCA Appeal Grp. v. EPA, 355 

F.3d 817, 840 (5th Cir. 2003). 

259See, e.g., Approval of Air Quality 

Implementation Plans; California; South Coast; 

Attainment Plan for 1997 PM2.5 Standards, 76 FR 

69928, November 9, 2011, at p. 69941; Approval 

and Promulgation of Implementation Plans; 

Arizona—Maricopa County PM–10 Nonattainment 

Area; Serious Area Plan for Attainment of the 

Annual PM–10 Standard, 65 FR 19964, April 13, 

2000, at pp. 19983–19984. 

260The enhanced enforcement of the curtailment 

program is expected to yield 0.090 tons per day in 

PM2.5 emissions reductions and increase SO2

emissions by 0.038 tons per day (the increase in 

SO2 caused by the shift from wood burning to 

heating oil). See State Air Quality Control Plan, Vol. 

II, section III.D.7.11.5.1. 

261State Air Quality Control Plan, Vol. II, section 

III.D.7.11.5. 

262 Id. at section III.D.7.11.6. 

263See, e.g., Approval of Air Quality 

Implementation Plans; California; South Coast; 

Attainment Plan for 1997 PM2.5 Standards, 76 FR 

69928, November 9, 2011, at p. 69941. 

addresses the largest source category of 

direct PM2.5 emissions in the 

nonattainment area and is not otherwise 

included in the Fairbanks Revised 

189(d) Plan control strategy. The EPA 

expects this continency measure would 

produce emissions benefits in addition 

to the projected emissions reductions 

under the control strategy and were not 

required to meet RFP or to attain by the 

attainment date. 

This contingency measure would go 

into effect once triggered by an EPA 

determination, as provided in 18 AAC 

50.030(c). Alaska projected this first 

contingency measure will result in 

emissions reductions of 0.086 tons per 

day PM2.5 but increase SO2 emissions by 

0.047 tons per day.256 This contingency 

measure represents 84 percent of one 

year’s worth of progress for direct PM2.5

reductions, but, the increase in SO2

emissions would not meet the one year’s 

worth of progress metric for SO2. 

For the reasons provided in the 

preceding paragraphs, the EPA is 

proposing to determine that this 

measure meets the requirements for 

contingency measures in 40 CFR 

51.1014 and CAA Section 172(c)(9). In 

section II.G.4.d of this preamble, we 

address whether approval of this 

contingency measure also supports 

approval of the overarching attainment 

plan contingency measures element of 

the Fairbanks Revised 189(d) Plan for 

purposes of the 2006 24-hour PM2.5

NAAQS in the Fairbanks PM2.5

Nonattainment Area. 

ii. Enforceable Commitments To 

Enhance Enforcement of the Solid FuelBurning Appliance Curtailment Program 

and Removal of Wood Stoves 

These submitted measures take the 

form of enforceable commitments. 

According to Alaska, these measures 

would achieve surplus emissions 

reductions by increasing the compliance 

rate with the curtailment program from 

38 percent to 65 percent and the wood 

stove removal measure from 30 percent 

to 45 percent. For the reasons stated in 

the following paragraphs, the EPA 

proposes to determine that these 

measures meet the CAA requirements 

for enforceable commitments. The EPA 

is further proposing to approve these 

commitments into the Alaska SIP as 

SIP-strengthening but not as 

contingency measures. 

First, Alaska’s commitments meet the 

CAA’s requirements for enforceable 

commitments. Under the CAA, an 

enforceable commitment must be: (1) a 

specific enforceable requirement, not 

merely an aspirational goal; and (2) 

enforceable as a practical matter (i.e., 

the public will have sufficient 

information to enforce the state’s 

compliance with its commitment).257 In 

the submitted measures, Alaska 

committed to increase the allocation of 

annual staff hours by a specific number 

of hours dedicated to implementing and 

enforcing specific SIP measures. Thus, 

the commitment is sufficiently concrete 

and not merely an aspirational goal. 

Moreover, Alaska committed to publish 

a report of its compliance with these 

commitments. The report will not only 

include the number of hours dedicated 

to implementing and enforcing the 

specific measures, but also other 

compliance metrics such as number of 

warning letters and the number of wood 

stoves removed. Thus, the commitments 

are enforceable as a practical matter. 

In addition to the two criteria above, 

the EPA has assessed whether to 

approve an enforceable commitment 

based on consideration of the following 

three factors: (1) whether the 

commitment addresses a limited portion 

of the CAA requirement; (2) whether the 

state is capable of fulfilling its 

commitment; and (3) whether the 

commitment is for a reasonable and 

appropriate period of time.258 Regarding 

the first factor, in the past, states have 

relied on enforceable commitments as 

part of their overall control strategy to 

achieve the NAAQS.259 Thus, the EPA 

has typically assessed whether the 

emissions reductions attributable to the 

state’s enforceable commitments are a 

limited portion of the emissions 

reductions necessary to achieve 

attainment or RFP. 

The EPA notes that Alaska structured 

its enforceable commitments as 

contingency measures. Thus, in the 

Fairbanks Revised 189(d) Plan, Alaska 

assessed the amount of emissions 

reductions that the commitments could 

achieve with respect to the one year’s 

worth of progress and one year’s worth 

of RFP metrics for contingency 

measures. Alaska determined that the 

emissions reductions attributable to the 

commitments are a small portion of the 

emissions reductions towards the 

recommended one year’s worth of 

progress and one year’s worth of RFP 

metrics for contingency measures, 

respectively.260 Alaska projected that 

emissions reductions attributable to the 

commitments will yield 38 percent of 

the emissions reductions towards oneyear’s work of progress target.261

The EPA is proposing to determine 

that Alaska’s enforceable commitments 

included in State Air Quality Control 

Plan, Vol. II, section III.D.7.11.2.1 

address a limited portion of the CAA 

requirement. The EPA is not proposing 

to approve these commitments as 

contingency measures under CAA 

section 172(c)(9). If the EPA finalizes 

approval, these commitments will 

become part of Alaska’s overall control 

strategy. Viewed in this light, Alaska 

would not rely on the enforceable 

commitments to achieve attainment or 

RFP. 

As to the second enforceable 

commitments factor, Alaska has 

demonstrated that it can fulfill its 

commitments. According to Alaska, the 

commitment to re-allocate staff hours is 

within the Alaska Department of 

Environmental Conservation Air Quality 

Division’s existing budget and control. 

In the Fairbanks Revised 189(d) Plan, 

Alaska stated that it has the capacity to 

implement the reallocation of staffing 

hours it is making in the enforceable 

commitments and to maintain them 

indefinitely.262

Finally, the commitments are for a 

reasonable and appropriate period of 

time. For this factor, the EPA typically 

assesses the state’s schedule for 

promulgating specific control measures 

to achieve the promised emissions 

reductions and whether the schedule 

comports with the RFP and attainment 

deadlines.263 Here, Alaska is not relying 

on the enforceable commitment to 

achieve RFP or attainment. Therefore, 

the EPA proposes to determine that this 

factor is not determinative with respect 

to Alaska’s enforceable commitments. 


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264State Air Quality Control Plan, Vol. II, section 

III.D.7.11.4.3. 

265 40 CFR 51.1014(a). See Clean Air Plans; 2008 

8-Hour Ozone Nonattainment Area Requirements; 

San Joaquin Valley, California, 84 FR 11198, March 

25, 2019, at pp. 11200, 11203. 

266See Approval and Promulgation of Air Quality 

Implementation Plans; Michigan; Federal 

Implementation Plan for the Detroit Sulfur Dioxide 

Nonattainment Area, 87 FR 61514, Oct. 12, 2022, 

at p. 61522; see also SO2 Guideline Document, U.S. 

Environmental Protection Agency, Office of Air 

Quality Planning and Standards, Research Triangle 

Park, NC 27711, EPA–452/R–94–008, February 1994 

(1994 SO2 Guideline); Guidance for 1-Hour SO2

Nonattainment Area SIP Submissions, Office of Air 

Quality Planning and Standards, Stephen D. Page, 

April 23, 2014. 

267 Id. 268 Guidance for 1-Hour SO2 Nonattainment Area 

SIP Submissions, Office of Air Quality Planning 

and Standards, Stephen D. Page, April 23, 2014, at 

p. 69. 

269 87 FR 61514, Oct. 12, 2022, at p. 61522. 

270 Id. 

271State Air Quality Control Plan, Vol. II, section 

III.D.7.6.9.3. 

272 Id. 

273 Id. 

Rather, Alaska structured the 

commitments as contingency measures 

triggered upon any of the EPA findings 

in 40 CFR 51.1014. Once triggered, 

Alaska committed to increasing staff 

hours within 60 days of the triggering 

event and maintain the staff hours 

unless and until the State could revise 

them through a SIP revision.264

The EPA is proposing to approve the 

measures as SIP-strengthening but not 

as contingency measures under CAA 

section 172(c)(9) for the following 

reasons. The EPA acknowledges that the 

enforceable commitments meet many of 

the regulatory requirements in 40 CFR 

51.1014. Specifically, the enforceable 

commitments are subject to Alaska’s 

regulation 18 AAC 50.030(c) that is 

consistent with the triggers in 40 CFR 

51.1014(a). The Fairbanks Revised 

189(d) Plan also includes a description 

of the specific trigger mechanisms for 

the commitment. The commitments also 

specify the timeframe within which 

they would become effective. Finally, 

Alaska is not relying on the emissions 

reductions that may occur as a result of 

increased compliance rates attributable 

to the enforceable commitments as part 

of its control strategy, to meet RFP 

requirements, or in its attainment 

demonstration. 

However, outside of the SO2

nonattainment context, the EPA has not 

considered increased enforcement of 

existing measures in the control strategy 

as ‘‘implementation of specific 

measures’’ that would ‘‘take effect with 

minimal further action by the state of 

the EPA’’ following a triggering 

event.265 The EPA has approved 

enhanced enforcement as satisfying the 

contingency measure requirement in the 

context of SO2 NAAQS nonattainment 

areas.266 This is for several reasons. 

First, the procedures and methods for 

quantifying and predicting SO2

concentrations are less uncertain than 

for other criteria pollutants, especially 

those that may result from secondary 

formation from multiple precursors, 

such as PM2.5.267 Second, the regulated 

sources in SO2 nonattainment areas are 

typically one or a few major stationary 

sources that are the main cause of 

exceedances of the SO2 NAAQS.268

Third, the control efficiencies for SO2

control measures are well understood 

and are less prone to uncertainty than 

for other criteria pollutants.269 Thus, the 

EPA has reasoned in the context of SO2

NAAQS nonattainment areas that if the 

nonattainment area fails to meet RFP or 

achieve attainment, then that failure is 

likely due to violations of the control 

strategy by the major stationary source 

regulated in the attainment plan 

—rather than an inadequacy of the 

control strategy.270 Hence, for purposes 

of the SO2 NAAQS, contingency 

measures comprised of a comprehensive 

enforcement program are sufficient. 

By contrast, PM2.5 NAAQS 

nonattainment areas typically include 

hundreds or thousands of individual 

sources (including multiple categories 

of major stationary, area, and mobile 

sources) of emissions of direct PM2.5 and 

multiple PM2.5 precursors. Thus, it is 

not appropriate for a state or the EPA to 

presume that a failure to meet RFP or to 

attain is presumptively the result of a 

single easily identified source to have 

violated the emissions limitations in an 

attainment plan for the PM2.5 NAAQS. 

Accordingly, the EPA has assessed 

whether the situation in the Fairbanks 

PM2.5 Nonattainment Area is 

sufficiently analogous to an SO2

nonattainment area to warrant 

extending the EPA’s approach to SO2

contingency measures to Alaska’s 

enforceable commitments. The EPA 

acknowledges that the emissions 

inventories and RFP provisions of the 

Fairbanks Revised 189(d) Plan make 

clear that the dominant contributor to 

elevated PM2.5 concentrations in the 

nonattainment area is the solid fuelburning device source category, i.e., 

wood stoves. The EPA has approved 

Alaska’s control strategy as meeting 

BACM for this source category and is 

proposing to determine that the 

Fairbanks Revised 189(d) Plan meets the 

CAA section 189(d) requirements. Thus, 

a failure to achieve RFP or QM 

requirements, or to achieve attainment 

could be attributable to widespread 

noncompliance with preexisting 

measures limiting emissions from the 

solid fuel-burning device source 

category. Although comprised of 

numerous relatively small sources, 

widespread noncompliance could 

cumulatively be comparable to that by 

a single major stationary source. 

Therefore, if the State were to fail to 

meet an RFP or QM requirement or fail 

to attain the NAAQS by the applicable 

attainment date, then improving 

compliance with the Solid Fuel-Burning 

Appliance Curtailment Program and 

date certain removal requirement could 

be critical to ensuring the area achieves 

progress towards attainment. As 

previously discussed, the EPA is 

proposing to approve the State’s 

determination that there are no other 

feasible measures that would meet 

contingency measures requirements. 

The EPA also acknowledges that 

Alaska’s methods of assessing current 

and predicting future compliance rates 

with its control strategy have improved 

over time. This is evident by the results 

of Alaska’s Fairbanks Winter Home 

Heating Energy Model and Multiple 

Residential Heating Surveys.271 In these 

ways, the situation in Fairbanks shares 

similarities to SO2 nonattainment areas. 

However, critical distinctions remain 

that suggest the Fairbanks PM2.5

Nonattainment Area should not be 

treated the same as an SO2

nonattainment area for the purposes of 

contingency measures requirements. In 

particular, the major contributors to 

ambient PM2.5 levels in Fairbanks are 

wood stoves, which emit direct PM2.5, 

and oil furnaces, which emit SO2, a 

PM2.5 precursor for area source 

purposes. There are tens of thousands of 

these area sources throughout the 

nonattainment area.272 They vary in 

make, model, age, and emissions 

potential.273 Importantly, actual 

emissions are highly dependent on 

operator behavior—particularly for 

wood stoves. This is different from the 

single or handful of major stationary 

sources that a state typically regulates in 

SO2 NAAQS nonattainment areas. 

By extension, measuring and 

predicting compliance with controls on 

wood stoves and oil furnaces is less 

precise than SO2 emissions controls on 

major stationary sources. In addition, 

assuring compliance by thousands of 

individual wood stove operators is 

significantly more resource intensive 

than enforcement against an SO2

source—particularly in detecting 

violations. Thus, while a comprehensive 

enforcement program to assure 

compliance by major stationary sources 

in SO2 nonattainment areas satisfies the 


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274The EPA solicits comments on this assessment 

and conclusion. Given that Alaska’s enforceable 

commitments meet all other requirements in 40 

CFR 51.1014, the EPA may approve these 

commitments as contingency measures if 

commenters provide a compelling basis to show 

that the EPA should treat the Fairbanks PM2.5

Nonattainment Area as analogous to an SO2

nonattainment area for the purposes of contingency 

measures. 

275Applying Alaska’s interpollutant trading 

mechanism, the combined emissions reductions for 

PM2.5 and SO2 are estimated to be 0.077 tons per 

day, representing 62 percent of the one year’s of 

interpollutant emissions reductions for PM2.5 and 

SO2. See State Air Quality Control Plan, Vol. II, 

section III.D.7.11.5.2; see also State Air Quality 

Control Plan, Vol. II, section III.D.7.11, Table 7.11– 

6. 

276For further information on transportation 

conformity rulemakings, policy guidance and 

outreach materials, see the EPA’s website at https:// 

www.epa.gov/state-and-local-transportation. 

277 88 FR 84626, December 5, 2023, at p. 84676. 

278See section II.B.2. Note that 40 CFR 

93.102(b)(2)(iv) indicates that NOX would apply in 

transportation conformity unless the appropriate 

finding has been made or if the SIP does not 

establish a budget for NOX. 

CAA requirement that contingency 

measures be comprised of ‘‘specific 

measures’’ that would ‘‘take effect with 

minimal further action by the state or 

EPA’’ following a triggering event, this 

is not the case for PM2.5 nonattainment 

areas.274

Thus, the EPA proposes to approve 

the enforceable commitments in State 

Air Quality Control Plan, Vol. II, section 

III.D.7.2.1 as SIP-strengthening that will 

enhance the State’s overall approach to 

attaining and maintaining the NAAQS 

in the Fairbanks PM2.5 Nonattainment 

Area. 

d. Sufficiency of Emissions Reductions 

From Alaska’s Contingency Measures 

Alaska’s contingency measure, 

reducing the solid fuel-burning device 

curtailment thresholds, would achieve 

approximately 0.086 tons per day PM2.5

emissions reductions with an increase 

of 0.047 tons per day SO2 emissions.275

This falls short of the one year’s worth 

of progress metric for both pollutants, 

0.102 tons per episode day of direct 

PM2.5 emissions and 0.115 tons per day 

of SO2 emissions. The estimates of 

emissions reductions from the other two 

contingency measures related to 

enhanced enforcement are not included 

in this calculation because the EPA is 

proposing to approve them as SIPstrengthening measures. However, as 

discussed in section II.G.3 of this 

preamble, the EPA proposes to 

determine that Alaska has provided a 

reasoned justification for why the state 

cannot adopt additional contingency 

measures to make up the shortfall. 

Based on the reasons in the preceding 

paragraphs, the EPA is proposing to 

approve the Fairbanks Revised 189(d) 

Plan as meeting the contingency 

measures requirements in CAA section 

172(c)(9) and 40 CFR 51.1014. 

H. Motor Vehicle Emission Budgets for 

Transportation Conformity 

1. Statutory and Regulatory 

Requirements Regarding the Motor 

Vehicle Emission Budgets 

CAA section 176(c) requires Federal 

activities in nonattainment and 

maintenance areas to conform to the 

SIP’s purpose of eliminating or reducing 

the severity and number of violations of 

the NAAQS and achieving expeditious 

attainment of the standards. Conformity 

to the SIP means that such activities 

will not: (1) cause or contribute to any 

new violation of a NAAQS; (2) increase 

the frequency or the severity of an 

existing violation; or (3) delay timely 

attainment of any NAAQS or interim 

milestones. 

Transportation plans, transportation 

improvement programs (TIPs), and 

transportation projects involving 

Federal Highway Administration 

(FHWA) or Federal Transit 

Administration (FTA) funding or 

approval are subject to the 

transportation conformity rule (40 CFR 

51.390 and part 93, subpart A). Under 

this rule, metropolitan planning 

organizations (MPOs) in nonattainment 

and maintenance areas coordinate with 

state air quality and transportation 

agencies, the EPA, FHWA and FTA to 

demonstrate that an area’s 

transportation plan and TIP conform to 

the applicable SIP. This demonstration 

typically includes a regional emissions 

analysis that shows that estimated 

emissions from existing and planned 

highway and transit systems are less 

than or equal to the SIP’s motor vehicle 

emissions budgets (‘‘budgets’’) that the 

EPA has found adequate or approved. 

An attainment plan for the PM2.5

NAAQS should include budgets for the 

attainment year and each required RFP 

year, as appropriate. Budgets are 

generally established for specific years 

and specific pollutants or precursors 

and reflect all of the motor vehicle 

control measures contained in the 

attainment and RFP demonstrations (40 

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

Attainment plans for PM2.5 NAAQS 

would identify motor vehicle emission 

budgets for the attainment year and each 

RFP year for direct PM2.5 and typically 

for NOX (unless certain criteria are met 

in the transportation conformity rule, 

see 40 CFR 93.102(b)(2)(iv)), and for 

VOCs, SO2, and NH3 if certain criteria in 

the transportation conformity rule are 

met (see 40 CFR 93.102(b)(2)(v)). Direct 

PM2.5 emission budgets would include 

direct PM2.5 motor vehicle emissions 

from tailpipe, brake wear, and tire wear. 

A state should also consider whether reentrained paved and unpaved road dust 

are significant contributors and should 

be included in the direct PM2.5 budget. 

See 40 CFR 93.102(b) and 93.122(f) and 

the conformity rule preamble at 69 FR 

40004, July 1, 2004, at pp. 40031– 

40036.276

2. Summary of the EPA’s Prior Action 

Regarding the Motor Vehicle Emission 

Budgets 

The EPA disapproved the budgets for 

the Fairbanks PM2.5 Nonattainment Area 

in the December 5, 2023, final rule.277

The EPA evaluated the motor vehicle 

emissions budgets developed by Alaska 

against our adequacy criteria in 40 CFR 

93.118(e)(4) as part of our review of the 

submitted SIP. The EPA found that the 

budgets were clearly identified and 

precisely quantified using 

MOVES2014b, with appropriate 

consultation among Federal, State, and 

local agencies. However, the EPA found 

that the budgets did not meet other 

adequacy criteria: the budgets, when 

considered together with all other 

emissions sources, must be consistent 

with applicable RFP or attainment 

requirements, and must be consistent 

with and clearly related to the emissions 

inventory and the control measures in 

the SIP, see 40 CFR 93.118(e)(4)(iv) and 

(v). Because the control strategy in the 

Fairbanks Serious Plan and Fairbanks 

189(d) Plan did not include all required 

control measures, the budgets did not 

reflect all the required control measures. 

3. Summary of the State’s Submission 

Regarding the Motor Vehicle Emission 

Budgets 

The Fairbanks Revised 189(d) Plan 

includes budgets for direct PM2.5 for 

each of the upcoming RFP years (2023, 

2026, and 2029) and the 2027 

attainment year identified by Alaska. 

Budgets for NOX were not included 

because Alaska demonstrated that NOX

does not significantly contribute to 

PM2.5 formation in the Fairbanks PM2.5

Nonattainment Area, and the EPA 

finalized approval of that precursor 

demonstration on December 5, 2023.278

For VOC, SO2 and NH3, in accordance 

with 40 CFR 93.102(b)(2)(v), 

transportation-related emissions of these 


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279Under 40 CFR 93.102(b)(2)(v), the 

requirements of the transportation conformity rule 

apply for VOC, SO2, and/or NH3 in a PM2.5 area if 

either (1) the EPA Regional Administrator or the 

director of the state air agency makes a finding that 

transportation-related emissions of any of these 

precursors within the nonattainment area are a 

significant contributor to the PM2.5 nonattainment 

problem and has so notified the MPO and DOT, or 

(2) if the applicable implementation plan or 

submission establishes an approved or adequate 

budget for such emissions as part of the reasonable 

further progress, attainment or maintenance 

strategy. Because neither criterion is met for the 

Fairbanks area, budgets were not included for VOC, 

SO2, and NH3. 

280 40 CFR 93.118(e)(4)(i). 

281 40 CFR 93.118(e)(4)(ii). 

282 40 CFR 93.118(e)(4)(vi). 

283 40 CFR 93.118(e)(4)(vi). 

284However, the budgets in submitted 

implementation plans do not supersede the budgets 

in an approved SIP submission for the same CAA 

requirement and the period of years addressed by 

the previously approved SIP submission, unless the 

EPA specifies otherwise in its approval of a SIP 

submission. 40 CFR 93.118(e)(4)(1). 

285 42 U.S.C. 7513a(d). 

286 42 U.S.C. 7502(c)(3). 

precursors have not been found to be 

significant.279

The direct PM2.5 budgets were 

calculated using the MOVES3 vehicle 

emissions model, which was the latest 

on-road mobile sources emissions 

model available at the time Alaska 

started developing the attainment plan 

inventory. Although a major model 

update was released in September 2023, 

MOVES4, the motor vehicle emission 

budgets were developed using 

MOVES3.0.3 (released January 2022) as 

significant work had already been 

completed on the SIP amendment prior 

to the release of MOVES4. The use of 

MOVES3 was agreed upon following 

consultation with applicable Federal, 

state, and local agencies. 

Alaska used local fleet and fuel inputs 

and the Fairbanks Area Surface 

Transportation Planning (FAST 

Planning) travel demand model to 

generate local vehicle travel activity 

estimates over the six-month 

nonattainment season (October through 

March). The average winter day 

emissions were used by Alaska to set 

the motor vehicle emissions budgets. 

Exceedances of the 2006 24-hour PM2.5

NAAQS in the Fairbanks PM2.5

Nonattainment Area occur almost 

exclusively during the winter months. 

Alaska executed MOVES3 with locally 

developed inputs representative of 

wintertime 2019–2020 conditions. Table 

6 of this preamble summarizes the 

regional average winter day on-road 

vehicle PM2.5 emission budgets and the 

related CAA milestone for the 

nonattainment area. 

TABLE 6—PM2.5 MOTOR VEHICLE

EMISSION BUDGETS BY MILESTONE

YEAR

Calendar 

year 

PM2.5

on-road 

budgets 

(tons per day) 

CAA-related 

milestone 

2020 ......... 0.074 Base year. 

2023 ......... 0.062 RFP. 

2026 ......... 0.054 RFP. 

2027 ......... 0.052 Attainment. 

TABLE 6—PM2.5 MOTOR VEHICLE

EMISSION BUDGETS BY MILESTONE

YEAR—Continued 

Calendar 

year 

PM2.5

on-road 

budgets 

(tons per day) 

CAA-related 

milestone 

2029 ......... 0.049 RFP. 

Source: State Air Quality Control Plan, Vol 

II, section III.D.7.14, Table 7.14–2. 

4. The EPA’s Evaluation and Proposed 

Action Regarding the Motor Vehicle 

Emission Budgets 

We have evaluated the motor vehicle 

emissions budgets developed by Alaska 

against our adequacy criteria in 40 CFR 

93.118(e)(4) as part of our review. 

Because the EPA believes the budgets 

meet the criteria in the transportation 

conformity regulation at 40 CFR 

93.118(e)(4), the EPA proposes to 

approve them as part of this SIP 

submission that addresses attainment 

and RFP. 

The Fairbanks Revised 189(d) Plan 

was submitted by the Alaska Governor’s 

designee—the Commissioner of Alaska 

Department of Environmental 

Conservations.280 Consultation among 

Federal, State, and local agencies 

occurred prior to Alaska’s submission of 

the Fairbanks Revised 189(d) Plan.281

This consultation is documented in the 

State Air Quality Control Plan, Vol. II, 

section III.D.7.14. The budgets are 

clearly identified and precisely 

quantified (40 CFR 93.118(e)(4)(iii)).282

The EPA proposes to find that the 

budgets are consistent with applicable 

RFP and attainment requirements (40 

CFR 93.118(e)(4)(iv)), as well as the 

emissions inventory and control 

measures in the Fairbanks Revised 

189(d) Plan (40 CFR 93.118(e)(4)(v)). 

The Fairbanks Revised 189(d) Plan also 

includes Alaska’s explanations and 

documentation for any revisions to the 

Fairbanks Serious Plan and initial 

Fairbanks 189(d) Plan, including 

revisions to control measures, 

previously submitted budgets, and prior 

attainment projections.283

In addition to proposing approval of 

the budgets, the EPA is also initiating 

the adequacy review process for the 

budgets in this proposed rulemaking. 

When reviewing submitted SIPs 

containing budgets, the EPA reviews 

budgets for adequacy. Once the EPA 

affirmatively finds the submitted budget 

is adequate for transportation 

conformity purposes, that budget must 

be used by state and Federal agencies in 

determining whether proposed 

transportation activities conform to the 

SIP as required by section 176(c) of the 

CAA. See 40 CFR 93.118(e)(4)(1).284 The 

EPA may find budgets adequate before 

the SIP is approved in a final rule. 

The substantive criteria the EPA uses 

for determining adequacy of a budget 

are set out in 40 CFR 93.118(e)(4); these 

criteria were discussed above as the 

basis for the EPA’s proposed approval. 

The process for determining adequacy is 

found in 40 CFR 93.118(f) and consists 

of three basic steps: (1) public 

notification of a SIP submission; (2) a 

public comment period; and (3) the 

EPA’s adequacy determination. The 

EPA can begin an adequacy review 

through a proposed rulemaking in the 

Federal Register based on the 

transportation conformity regulation at 

40 CFR 93.118(f)(2). This proposed 

rulemaking notifies the public that the 

EPA has received a SIP submission with 

budgets that the EPA will review for 

adequacy and begins the public 

comment period. The EPA invites the 

public to comment on the adequacy of 

budgets as well as other actions the EPA 

is proposing in this proposed 

rulemaking. Comments must be 

submitted by the close of the comment 

period. See the DATES section of this 

document for details. 

Interested members of the public can 

access the Fairbanks Revised 189(d) 

Plan and other relevant information at 

https://www.regulations.gov, under 

Docket ID No. EPA–R10–OAR–0595. 

Following the EPA’s public comment 

period, the EPA will consider any 

comments received. 

III. Summary of Proposed Action 

A. Proposed Approval 

In this action, the EPA is proposing to 

approve the submitted revisions to the 

Alaska SIP as meeting the following 

Serious Plan and CAA section 189(d) 285

required elements for the 2006 24-hour 

PM2.5 NAAQS Fairbanks Nonattainment 

Area: 

1. The 2020 base year emissions 

inventory (CAA section 172(c)(3); 286 40 

CFR 51.1008(c)(1)) for areas subject to 

CAA section 189(d)); 


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287 42 U.S.C. 7502(c)(1). 

288 42 U.S.C. 7513a(e). 

289 42 U.S.C. 7513a(b)(1)(B). 

290 Id. 

291 42 U.S.C. 7513a(d). 

292 42 U.S.C. 7513(c)(2); 7513a(b)(1)(A). 

293 42 U.S.C. 7502(c)(2). 

294 42 U.S.C. 7513a(c). 

295 42 U.S.C. 7502(c)(9). 

296The EPA is not proposing to take action on 

Alaska’s SO2 BACT determinations in State Air 

Quality Control Plan, Vol. III, Appendix III.D.7.7 at 

this time. If the EPA does not finalize approval of 

the SO2 precursor demonstration, then the EPA will 

propose action on Alaska’s SO2 BACT 

determinations separately. 

2. The 2027 attainment projected 

emissions inventory (CAA section 

172(c)(1); 287 40 CFR 51.1008(c)(2)); 

3. The State’s PM2.5 major stationary 

source precursor demonstration for SO2

emissions (CAA section 189(e); 288 40 

CFR 51.1006(a)); 

4. The control strategy as meeting the 

BACM requirements under CAA section 

189(b)(1)(B) 289 and 40 CFR 51.1010(a) 

for the following emission source 

categories: 

a. Requirements for wood sellers; 

b. Coal-fired heating devices; 

c. Coffee roasters; 

d. Weatherization and energy 

efficiency measures; and 

e. Mobile source emissions; 

5. Control strategy BACT 

requirements for direct PM2.5 emissions 

(CAA section 189(b)(1)(B) 290 and 40 

CFR 51.1010(a)) for the following 

emission sources: 

a. Chena Power Plant; 

b. Doyon-Fort Wainwright Central 

Heating and Power Plant; 

c. University of Alaska Fairbanks 

Power Plant; 

d. Zehnder Facility; 

e. North Pole Power Plant; 

6. Additional measures (beyond those 

already adopted in previous 

nonattainment plan SIP submissions for 

the area as RACM/RACT, BACM/BACT, 

and Most Stringent Measures (MSM) (if 

applicable) under CAA section 

189(d) 291 and 40 CFR 51.1010(c); 

7. Attainment demonstration and 

modeling meeting the requirements of 

CAA sections 188(c)(2) and 

189(b)(1)(A) 292 and 40 CFR 51.1003(c) 

and 51.1011; 

8. Reasonable further progress 

provisions meeting the requirements of 

CAA section 172(c)(2) 293 and 40 CFR 

51.1012; 

9. Motor vehicle emission budgets 

meeting the requirements under 40 CFR 

93.118; 

10. Quantitative milestones meeting 

the requirements of CAA section 

189(c) 294 and 40 CFR 51.1013; 

11. Contingency measures meeting the 

requirements of CAA section 

172(c)(9) 295 and 40 CFR 51.1014 

applicable to Serious areas subject to 

CAA section 189(b) and 189(d). 

The EPA is proposing to approve the 

following submitted sections of the 

State Air Quality Control Plan for the 

Fairbanks PM2.5 Nonattainment Area, 

State effective December 14, 2024: 

1. Volume II, section III.D.7.06 

Emissions Inventory; 

2. Volume II, section III.D.7.07 

Control Strategy; 

3. Volume II, section III.D.7.08 

Modeling; 

4. Volume II, section III.D.7.09 

Attainment Demonstration; 

5. Volume II, section III.D.7.10 

Reasonable Further Progress and 

Quantitative Milestones; 

6. Volume II, section III.D.7.11 

Contingency Measures; 

7. Volume II, section III.D.7.12 

Emergency Episode Plan; 

8. Volume II, section III.D.7.14 

Conformity and Motor Vehicle Emission 

Budgets; 

9. Volume III, Appendix III.D.7.06 

Emissions Inventory; 

10. Volume III, Appendix III.D.7.07 

Control Strategy; 296

11. Volume III, Appendix III.D.7.08 

Modeling; 

12. Volume III, Appendix III.D.7.09 

Attainment Demonstration; 

13. Volume III, Appendix III.D.7.10 

Reasonable Further Progress and 

Quantitative Milestones; 

14. Volume III, Appendix III.D.7.14 

Conformity and Motor Vehicle Emission 

Budgets. 

The EPA is also proposing to approve 

and incorporate by reference submitted 

regulatory changes into the Alaska SIP. 

Upon final approval, the Alaska SIP will 

include the following regulations, State 

effective December 8, 2024: 

1. 18 AAC 50.055 (industrial 

processes and fuel-burning equipment 

requirements), except (d)(2)(B); 

2. 18 AAC 50.076 (solid fuel-fired 

heating device fuel requirements; 

registration of commercial wood 

sellers), except (g)(11); 

3. 18 AAC 50.077 (standards for wood 

fired heating devices), except (g); 

4. 18 AAC 50.078 (additional control 

measures for a serious PM2.5

nonattainment area), except (c); 

5. 18 AAC 50.079 (provisions for coalfired heating devices); and 

6. 18 AAC 50.081 (Real estate 

transaction requirements; 

weatherization and energy efficiency). 

The EPA is also proposing to approve 

and incorporate by reference submitted 

permits into the Alaska SIP. Upon final 

approval, the Alaska SIP will include: 

1. Minor Permit AQ1121MSS04 Rev. 

1, Title Page, Table of Contents, List of 

Abbreviations and Acronyms, Section 1, 

Section 3, Section 4, and Section 6, 

only, State effective December 14, 2024 

(Doyon Utilities, LLC—Fort Wainwright 

(Privatized Emission Units); 

2. Minor Permit AQ0236MSS03 Rev. 

2, Title Page, Table of Contents, List of 

Abbreviations and Acronyms, Section 1, 

Section 3, Section 4, and Section 6, only 

State effective December 14, 2024 (U.S. 

Army Garrison Fort Wainwright); 

3. Minor Permit AQ0110MSS01 Rev. 

1, Title Page, Table of Contents, List of 

Abbreviations and Acronyms, Section 1, 

Section 3, Section 4, and Section 6, 

only, State effective December 14, 2024 

(Golden Valley Electric Association, 

North Pole Power Plant); 

4. Minor Permit AQ0109MSS01 Rev. 

2, Title Page, Table of Contents, List of 

Abbreviations and Acronyms, Section 1, 

Section 3, Section 4, and Section 6, 

only, State effective December 14, 2024 

(Golden Valley Electric Association, 

Zehnder Facility); 

5. Minor Permit AQ0315MSS02 

Revision 1, Title Page, Table of 

Contents, List of Abbreviations and 

Acronyms, Section 1, Section 3, Section 

4, and Section 6, only, State effective 

December 14, 2024 (Aurora Energy LLC, 

Chena Power Plant); 

6. Minor Permit AQ0316MSS08 

Revision 1, Title Page, Table of 

Contents, List of Abbreviations and 

Acronyms, Section 1, Section 3, Section 

4, and Section 6, only, State effective 

December 14, 2024 (University of 

Alaska Fairbanks, University of Alaska 

Fairbanks Campus). 

B. Adequacy Process 

In this action, the EPA is also 

initiating the adequacy process for the 

PM2.5 budgets included in this SIP 

submission. For further details, see 

section II.H.4. 

IV. Interim Final Determination and 

Deferral of Sanctions 

Please see the EPA’s Interim Final 

Determination published in the ‘‘Rules’’ 

section of this Federal Register. 

V. Incorporation by Reference 

In this document, the EPA is 

proposing to include regulatory text in 

an EPA final rule that includes 

incorporation by reference. In 

accordance with requirements of 1 CFR 

51.5, the EPA is proposing to 

incorporate by reference the regulations 

described in section III. of this 

document. The EPA has made, and will 

continue to make, these materials 

generally available through https://

www.regulations.gov and at the EPA 

Region 10 Office (please contact the 

person identified in the FOR FURTHER


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1634 Federal Register / Vol. 90, No. 5 / Wednesday, January 8, 2025 / Proposed Rules 

INFORMATION CONTACT section of this 

document for more information). 

VI. Statutory and Executive Order 

Reviews 

Additional information about these 

statutes and Executive Orders can be 

found at https://www.epa.gov/lawsregulations/laws-and-executive-orders. 

A. Executive Order 12866: Regulatory 

Planning and Review as Amended by 

Executive Order 14094: Modernizing 

Regulatory Review 

This action is not a significant 

regulatory action and was therefore not 

submitted to the Office of Management 

and Budget (OMB) for review. 

B. Paperwork Reduction Act (PRA) (44 

U.S.C. 3401 et. seq.) 

This action does not impose an 

information collection burden under the 

PRA, because this proposed SIP 

approval, if finalized, will not in-and-of 

itself create any new information 

collection burdens, but will simply 

approve certain State requirements for 

inclusion in the SIP. 

C. Regulatory Flexibility Act (RFA) (5 

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

I certify that this action will not have 

a significant economic impact on a 

substantial number of small entities 

under the RFA. This action will not 

impose any requirements on small 

entities. This proposed SIP approval, if 

finalized, will not in-and-of itself create 

any new requirements but will simply 

approve certain State requirements for 

inclusion in the SIP. 

D. Unfunded Mandates Reform Act 

(UMRA) (Pub. L. 104–4) 

This action does not contain any 

unfunded mandate as described in 

UMRA, 2 U.S.C. 1531–1538, and does 

not significantly or uniquely affect small 

governments. This action proposes to 

approve certain pre-existing 

requirements under State or local law 

and imposes no new requirements. 

Accordingly, no additional costs to 

State, local, or Tribal governments, or to 

the private sector, result from this 

action. 

E. Executive Order 13132: Federalism 

This action does not have federalism 

implications. It will not have substantial 

direct effects on the states, on the 

relationship between the national 

government and the states, or on the 

distribution of power and 

responsibilities among the various 

levels of government. 

F. Executive Order 13175: Coordination 

With Indian Tribal Governments 

This action does not have Tribal 

implications, as specified in Executive 

Order 13175, because the SIP revision 

that EPA is proposing to approve would 

not 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, and will 

not impose substantial direct costs on 

Tribal governments or preempt Tribal 

law. Thus, Executive Order 13175 does 

not apply to this action. 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

The EPA interprets Executive Order 

13045 as applying only to those 

regulatory actions that concern 

environmental health or safety risks that 

the EPA has reason to believe may 

disproportionately affect children, per 

the definition of ‘‘covered regulatory 

action’’ in section 2–202 of the 

Executive Order. This action is not 

subject to Executive Order 13045 

because this proposed SIP approval, if 

finalized, will not in-and-of itself create 

any new regulations, but will simply 

approve certain State requirements for 

inclusion in the SIP. 

H. Executive Order 13211: Actions That 

Significantly Affect Energy Supply, 

Distribution, or Use 

This action is not subject to Executive 

Order 13211, because it is not a 

significant regulatory action under 

Executive Order 12866. 

I. National Technology Transfer and 

Advancement Act (NTTAA) 

Section 12(d) of the NTTAA directs 

the EPA to use voluntary consensus 

standards in its regulatory activities 

unless to do so would be inconsistent 

with applicable law or otherwise 

impractical. The EPA believes that this 

action is not subject to the requirements 

of section 12(d) of the NTTAA because 

application of those requirements would 

be inconsistent with the CAA. 

J. Executive Order 12898: Federal 

Actions To Address Environmental 

Justice in Minority Populations and 

Low-Income Population 

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, or Tribal affiliation, or 

disability in agency decision-making 

and other Federal activities that affect 

human health and the environment.’’ 

The air agency did not evaluate EJ 

considerations as part of its SIP 

submission; the CAA and applicable 

implementing regulations neither 

prohibit nor require such an evaluation. 

The EPA did not perform an EJ analysis 

and did not consider EJ in this action. 

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 Order 

12898/14096 of achieving EJ for 

communities with EJ concerns. 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Carbon monoxide, 

Incorporation by reference, 

Intergovernmental relations, Lead, 

Nitrogen dioxide, Ozone, Particulate 

matter, Reporting and recordkeeping 

requirements, Sulfur oxides, Volatile 

organic compounds. 

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

Dated: December 17, 2024. 

Casey Sixkiller, 

Regional Administrator, Region 10. 

[FR Doc. 2024–30648 Filed 1–7–25; 8:45 am] 

BILLING CODE 6560–50–P 


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