Document ID: EPA-R10-OAR-2021-0060-0001
Agency: epa
Document Type: Proposed Rule
Title: Air Quality State Implementation Plans; Approvals and Promulgations: Alaska, Fairbanks North Star Borough; 2006 24-Hour PM2.5 Serious Area Plan
Posted Date: 2021-02-22T05:00Z

[Federal Register Volume 86, Number 33 (Monday, February 22, 2021)]
[Proposed Rules]
[Pages 10511-10520]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-03064]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R10-OAR-2021-0060; FRL-10017-16-Region 10]

Air Plan Approval; AK, Fairbanks North Star Borough; 2006 24-hour 
PM2.5 Serious Area Plan

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve parts of state implementation plan (SIP) submissions, submitted 
by the State of Alaska (Alaska or the State) to address Clean Air Act 
(CAA or Act) requirements for the 2006 24-hour fine particulate matter 
(PM2.5) national ambient air quality standards (NAAQS) in 
the Fairbanks North Star Borough PM2.5 nonattainment area 
(Fairbanks PM2.5 Nonattainment Area). EPA is also proposing 
to approve rule revisions and an associated air quality control plan 
chapter submitted by Alaska into the Federally-approved SIP. Alaska 
made these submissions on December 13, 2019, (Fairbanks Serious Plan) 
and December 15, 2020.

DATES: Comments must be received on or before March 24, 2021.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R10-
OAR-2021-0060, at https://www.regulations.gov. Follow the online 
instructions for submitting comments. Once submitted, comments cannot 
be edited or removed from regulations.gov. 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. 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 EPA.

Table of Contents

I. Background
II. Clean Air Act Requirements for PM2.5 Serious Area 
Plans and Summary of Proposal
III. Review of the Fairbanks Serious Plan
    A. Base Year Emissions Inventory
    B. PM2.5 Precursor Demonstration
    C. SIP Strengthening Measures
IV. Summary of Proposed Action
V. Incorporation by Reference
VI. Statutory and Executive Order Reviews

I. Background

    In 2009, EPA designated a portion of the Fairbanks North Star 
Borough as ``nonattainment'' for the 2006 24-hour PM2.5 
NAAQS of 35 micrograms per cubic meter ([mu]g/m\3\) (Fairbanks 
PM2.5 Nonattainment Area) (74 FR 58688, November 13, 
2009).\1\ Effective July 2, 2014, EPA classified the area as 
``Moderate'' (79 FR 31566, June 2, 2014). Subsequently, Alaska 
submitted, and the EPA approved, a plan to meet

[[Page 10512]]

Moderate nonattainment area requirements (82 FR 42457, September 8, 
2017) (``Fairbanks Moderate Plan'').
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    \1\ See 40 CFR 81.302.
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    On May 10, 2017, EPA determined that the State failed to attain the 
2006 24-hour PM2.5 NAAQS in the area by the outermost 
Moderate area attainment date of December 31, 2015 (82 FR 21711). 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 meet additional SIP requirements for 
the Fairbanks PM2.5 Nonattainment Area. In particular, the 
State was required to submit a Serious area nonattainment plan 
satisfying the requirements of CAA title I, part D, including the 
requirements of subpart 4, for the 2006 24-hour PM2.5 NAAQS 
and attain the 2006 24-hour PM2.5 NAAQS in the area by no 
later than the end of the tenth calendar year following designation 
(i.e., December 31, 2019). Prior to submitting the Fairbanks Serious 
Plan, Alaska revised its regulations and planning elements to further 
limit visible emissions and promote the use of certified heating 
devices and cleaner burning practices in the Fairbanks PM2.5 
Nonattainment Area and submitted the revised regulations to EPA on 
October 25, 2018 and November 28, 2018.\2\
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    \2\ We approved the remainder of the 2018 submissions in prior 
actions on June 5, 2019 (84 FR 26019), August 29, 2019 (84 FR 
45419), December 18, 2019 (84 FR 69331), and December 23, 2019 (84 
FR 70428).
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    Alaska submitted the Fairbanks Serious Plan on December 13, 2019 to 
address the Serious nonattainment area requirements for the 2006 24-
hour PM2.5 NAAQS. The Fairbanks Serious Plan includes 
further changes to heating device and cleaner burning practices 
regulations, among other control measures and planning elements. 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). On January 9, 2020, in accordance with section 
110(k)(1)(B) and part D of title I of the CAA, 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 section 188(e) of the 
CAA. On September 2, 2020, 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 plan to meet additional 
CAA requirements set forth in section 189(d) of the CAA by December 31, 
2020. Alaska submitted the revised plan on December 15, 2020. Alaska's 
December 15, 2020, submission makes several changes to the State Air 
Quality Control Plan, adopted and incorporated by reference into State 
law at 18 AAC 50.030(a).\3\ In particular, Alaska made additions to 
several chapters of the State Air Quality Control Plan, including 
Chapter III.D.7.12 (``Fairbanks Emergency Episode Plan''). Alaska also 
withdrew and replaced several other chapters. EPA is proposing to 
approve the base year emissions inventory and the PM2.5 
precursor demonstration elements of the Fairbanks Serious Plan. Alaska 
did not withdraw these portions of the State Air Quality Control Plan 
as part of the December 15, 2020, submission.\4\ Also, EPA is proposing 
to approve the updated Fairbanks Emergency Episode Plan that was 
adopted by the State on November 18, 2020 and was submitted on December 
15, 2020. EPA will act on the remainder of the December 15, 2020, 
submission at a later date.
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    \3\ See Jason W. Brune, Commissioner Alaska Department of 
Environmental Conservation, to Chris Hladick, U.S. EPA Region 10, 
December 15, 2020, letter included in the docket for this proposed 
action.
    \4\ Note that Alaska submitted an additional base year emissions 
inventory and updated PM2.5 precursor demonstrations as 
part of the December 15, 2020, submission. EPA is not proposing 
action on the additional base year emissions inventory or the 
updated PM2.5 precursor demonstration. EPA will propose 
action on these portions of the December 15, 2020, submission at a 
later date.
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    Alaska also made SIP submissions on October 25, 2018 and November 
28, 2018 (in addition to the December 13, 2019 submission), requesting 
EPA approval of specific changes to Alaska Administrative Code Title 
18, Environmental Conservation, Chapter 50, Air Quality Control (18 AAC 
50) State effective September 15, 2018 and January 8, 2019. The 
requests included in the October 25, 2018, and November 28, 2018 SIP 
submissions are discussed in section C of this preamble.

II. Clean Air Act Requirements for PM[bdi2].[bdi5] Serious Area Plans 
and Summary of Proposal

    Upon reclassification of a Moderate nonattainment area as a Serious 
nonattainment area under subpart 4 of part D, title I of the CAA, the 
Act requires the State to submit a Serious area nonattainment plan that 
addresses specific requirements.\5\ On August 24, 2016, EPA promulgated 
the final rule entitled, ``Fine Particulate Matter National Ambient Air 
Quality Standards: State Implementation Plan Requirements'' 
(PM2.5 SIP Requirements Rule).\6\ The PM2.5 SIP 
Requirements Rule is codified at 40 CFR part 51, subpart Z. The 
PM2.5 SIP Requirements Rule establishes regulatory 
requirements and provides interpretive guidance on the statutory SIP 
requirements that apply to states with areas designated nonattainment 
for the PM2.5 standards. In accordance with subpart 4 of 
part D, title I of the CAA and the PM2.5 SIP Requirements 
Rule at 40 CFR 51.1003(b), Serious area nonattainment plans must 
address the following requirements:
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    \5\ CAA section 189(b), 42 U.S.C. 7513a(b); see also 81 FR 
58010, 58074-58075, August 24, 2016.
    \6\ 81 FR 58010. Prior to promulgating the PM2.5 SIP 
Requirements Rule, EPA provided its interpretations of the CAA's 
requirements for particulate matter plans under part D, title I of 
the Act in the following guidance documents: (1) ``State 
Implementation Plans; General Preamble for the Implementation of 
Title I of the Clean Air Act Amendments of 1990'' (``General 
Preamble''); (2) ``State Implementation Plans; General Preamble for 
the Implementation of Title I of the Clean Air Act Amendments of 
1990; Supplemental'' (``General Preamble Supplement''); and (3) 
``State Implementation Plans for Serious PM-10 Nonattainment Areas, 
and Attainment Date Waivers for PM-10 Nonattainment Areas Generally; 
Addendum to the General Preamble for the Implementation of Title I 
of the Clean Air Act Amendments of 1990'' (``General Preamble 
Addendum'').
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    1. Base year emissions inventory meeting the requirements of CAA 
section 172(c)(3) and 40 CFR 51.1008(b)(1));
    2. Attainment projected emissions inventory meeting the 
requirements of CAA section 172(c)(1) and 40 CFR 51.1008(b)(2);
    3. Serious area nonattainment plan control strategy meeting the 
requirements of CAA section 189(b)(1)(B) and 40 CFR 51.1010, including 
provisions to assure that the best available control measures (BACM) 
and best available control technologies (BACT), for the control of 
direct PM2.5 and PM2.5 precursors are implemented 
no later than four years after the area is reclassified (CAA section 
189(b)(1)(B));
    4. Attainment demonstration and modeling meeting the requirements 
of CAA sections 188(c)(2) and 189(b)(1)(A) and 40 CFR 51.1011;
    5. Reasonable further progress (RFP) provisions meeting the 
requirements of CAA section 172(c)(2) and 40 CFR 51.1012;
    6. Quantitative milestones meeting the requirements of CAA section 
189(c) and 40 CFR 51.1013;

[[Page 10513]]

    7. An 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 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;
    8. Contingency measures meeting the requirements of CAA section 
172(c)(9) and 40 CFR 51.1014; and
    9. Nonattainment new source review provisions meeting the 
requirements of CAA section 189(b)(3) and 40 CFR 51.165.
    In the Serious area nonattainment plan, states must also satisfy 
the requirements for Moderate area plans in CAA section 189(a), to the 
extent the state has not already met those requirements in the Moderate 
area plan submitted for the area (see CAA section 189(b)(1), 40 CFR 
51.1003(b), and 81 FR 58010, 58075, August 24, 2016). In addition, the 
Serious area nonattainment plan must meet the general requirements 
applicable to all SIP submissions under section 110 of the CAA, 
including the requirement to provide necessary assurances that the 
implementing agencies have adequate personnel, funding, and authority 
under section 110(a)(2)(E), and the requirements concerning enforcement 
provisions in section 110(a)(2)(C).
    EPA is proposing to approve parts of the Fairbanks Serious Plan as 
meeting the base year emission inventory requirements and certain 
optional PM2.5 precursor demonstration requirements. EPA is 
also proposing to approve rule revisions and an associated air quality 
control plan chapter submitted by Alaska into the Federally-approved 
SIP (SIP strengthening). Therefore, the ensuing evaluation of the 
Fairbanks Serious Plan focuses on only the statutory and regulatory 
requirements applicable to these Serious area nonattainment plan 
provisions. Additionally, we are not evaluating whether the Fairbanks 
Serious Plan or the December 15, 2020, submission meets the additional 
planning obligations of CAA section 189(d) or 40 CFR 51.1003(c). We 
note that EPA approved the nonattainment new source review element of 
the Fairbanks Serious Plan on August 29, 2019 (84 FR 45419). We will 
take action on the remaining elements of the Fairbanks Serious Plan and 
the December 15, 2020, submission at a later date.

III. Review of the Fairbanks Serious Plan

A. Base Year Emissions Inventory

1. Statutory and Regulatory Requirements
    CAA section 172(c)(3) requires that states submit a comprehensive, 
accurate, 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. EPA discussed the emissions inventory 
requirements that apply to PM2.5 nonattainment areas, 
including Serious area nonattainment plan requirements, in the 
PM2.5 SIP Requirements Rule. The EPA codified these 
requirements in 40 CFR 51.1008.\7\ EPA has also issued additional 
guidance concerning emissions inventories for PM2.5 
nonattainment areas.\8\
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    \7\ 81 FR 58010, August 24, 2016, at pp. 58078-58079.
    \8\ ``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/air-emissions-inventory-guidance-implementation-ozone-and-particulate.
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    The base year emissions inventory for a Serious PM2.5 
nonattainment area must be one of the three years for which monitored 
data were used by EPA to reclassify the area to Serious, or another 
technically appropriate year justified by the state in its Serious area 
nonattainment plan SIP submission.\9\ 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 a 
particular NAAQS pollutant. 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. In the 
Serious area plan SIP submission, the state must include a rationale 
for providing annual or seasonal emission inventories, and 
justification for the period used for any seasonal emissions 
calculations.\10\
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    \9\ 40 CFR 51.1008(b)(1).
    \10\ 40 CFR 51.1008.
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    For the PM2.5 NAAQS, the base year inventory must 
include direct PM2.5 emissions, separately reported 
filterable and condensable PM2.5 emissions,\11\ and 
emissions of all chemical precursors to the formation of secondary 
PM2.5: nitrogen oxides (NOX), sulfur dioxide 
(SO2), volatile organic compounds (VOC), and ammonia 
(NH3).\12\
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    \11\ The Emissions Inventory Guidance identifies the types of 
sources for which EPA expects states to provide condensable PM 
emission inventories. Emissions Inventory Guidance, section 4.2.1 
(``Condensable PM Emissions''), 63-65.
    \12\ 40 CFR 51.1008.
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    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. In estimating 
mobile source emissions, a state should use the latest emissions models 
and planning assumptions available at the time the SIP is developed. 
States are also required to use EPA's ``Compilation of Air Pollutant 
Emission Factors'' (``AP-42'') road dust method for calculating re-
entrained road dust emissions from paved roads. 13 14
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    \13\ 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 emission tests 
results. 76 FR 6328 (February 4, 2011).
    \14\ AP-42 has been published since 1972 as the primary source 
of EPA's emission factor information. https://www.epa.gov/air-emissionsfactors-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.
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2. Summary of State's Submission
    The base year planning emissions inventory for direct 
PM2.5 and PM2.5 precursors (NOX, 
SO2, VOC, and ammonia) and the documentation for the 
inventory for the Fairbanks PM2.5 Nonattainment Area are 
located in Chapter III.D.7.6 (``Emissions Inventory Data'') and 
Appendix III.D.7.6 of the Fairbanks Serious Plan.
    The State developed the inventory using data sources and emission 
calculation methodologies from the approved Fairbanks PM2.5 
Moderate Plan as its starting point and then updated the emissions 
totals based on additional source and activity data collected since 
preparation of that inventory.
    The State based the 2013 base year emissions inventory on 
historical source activity data in calendar year 2013 for all source 
sectors. For point sources, the State updated emissions data for the 
2013 base year emissions inventory based on annual fuel use/process 
throughput by individual facility and emission unit.\15\ The State also 
included fuel-based ammonia emissions for point

[[Page 10514]]

sources in the 2013 inventory. Additional home heating survey data 
collected in winters 2012 through 2015 were used by the State to 
augment the estimates of residential space heating device/fuel mix and 
usage in the Moderate Plan based on the singular 2011 Home Heating 
survey. The State combined this broader sample of survey data to better 
reflect residential space heating activity within the nonattainment 
area for calendar year 2013. For both on-road and non-road vehicles, 
the State used EPA's latest vehicle emissions model, MOVES2014b, to 
replace emission estimates from the Moderate SIP based on its 
predecessor, MOVES2010a. Alaska used MOVES2014b emission factors based 
on local fleet/fuel characteristics and augmented with Fairbanks North 
Star Borough wintertime vehicle warmup and plug-in emission testing 
data. On-road vehicle activity (VMT and speeds) was based by the State 
on 2013 baseline travel demand model outputs from the Fairbanks 
Metropolitan Area Transportation System (FMATS) 2040 Metropolitan 
Transportation Plan (MTP) and 2045 MTP. Alaska used the 2014 National 
Emissions Inventory to represent Source Classification Code (SCC)-level 
annual emissions for fugitive dust, which were estimated to have no 
emissions during episodic wintertime conditions.
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    \15\ For directly emitted PM2.5, condensable and 
filterable components are separately reported, see Appendix 
III.D.7.6, Table 7-6-76. Alaska and EPA have determined that the 
point source sector is the only Source Classification Code (SCC) 
category that must include condensable and filterable 
PM2.5 information in the Fairbanks PM2.5 
Nonattainment Area.
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    The 2013 base year emissions inventory in the Fairbanks Serious 
Plan has its foundations in the emissions inventory development work 
conducted for the Moderate Plan, which was based on emission estimates 
for two historical calendar year 2008 episodes (January 23-February 10, 
2008 and November 2-17, 2008). The Fairbanks North Star Borough, Alaska 
Department of Environmental Conservation, and EPA collectively 
determined that these ``seasonal'' modeling episodes typify 
atmospheric/meteorological conditions and source activity/emission 
patterns within the nonattainment season when ambient PM2.5 
concentrations exceed the standard at design day or high percentile 
levels.\16\ Alaska believes that the average of emissions across the 
combined 35 days of the two historical episodes are well suited not 
just for attainment modeling, but also to satisfy seasonal planning 
inventory requirements. Similar to their development of a base year 
inventory for their Moderate Area Plan, Alaska used the meteorological 
scenarios and modeling from 2008 historical episodes as the basis for 
generating their 2013 base year planning inventory within this Serious 
SIP as provided in the PM2.5 SIP Requirements Rule.
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    \16\ The inventory is based on emissions estimated during the 
two 2008 episodes that represent weather conditions when exceedances 
of the 2006 24-hour PM2.5 NAAQS typically occur. The 
inventory is an average of emissions across all days in the two 
episodes. It represents the average season-day emissions, in which 
the emission inventory season is the wintertime episodes of cold and 
calm weather that coincide with exceedances of the standard (82 FR 
9035, February 2, 2017).
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    Table 1 in this preamble provides a summary of the episodic (24-
hour) average inventories in tons per day (tpd) of direct 
PM2.5 and PM2.5 precursors (NOX, 
SO2, VOC, and ammonia) for the 2013 base year.

 Table 1--Fairbanks PM2.5 Nonattainment Area 2013 Base Year Episode Average Daily Emissions (tons/day) by Source
                                                     Sector
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                                   Direct PM2.5
          Source sector                                 NOX             SO2             VOC           Ammonia
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Point Sources...................            1.23           10.45            7.22            0.23           0.051
Area, Space Heating (Total).....            2.59            2.34            3.62            9.50           0.136
Area, Space Heat, Wood..........            2.43            0.40            0.08            9.29           0.091
Area, Space Heat, Oil...........            0.06            1.72            3.42            0.10           0.003
Area, Space Heat, Coal..........            0.08            0.05            0.10            0.11           0.013
Area, Space Heat, Other.........            0.01            0.16            0.02            0.01           0.028
Area, Other \1\.................            0.22            1.72            0.03            2.27           0.045
On-Road Mobile..................            0.27            3.36            0.02            4.07           0.054
Non-Road Mobile \2\.............            0.15            0.86            6.10            0.41           0.000
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    Totals......................            4.46           18.73           17.00           16.48           0.286
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Source: Fairbanks Serious Plan, Chapter III.D.7.6, Table 7.6-10.
\1\ The ``Area, Other'' category includes minor stationary sources (e.g., asphalt plants, coffee roasters, etc.)
 
\2\ The ``non-road mobile'' category includes recreational vehicles, logging equipment, agricultural equipment,
  etc.

3. EPA's Evaluation and Proposed Action
    The 2013 base year emissions inventory meets the requirements of 
CAA section 172(c)(3) and 40 CFR 51.1008. Calendar year 2013 is an 
appropriate base year for the Fairbanks Serious Plan because it is one 
of the three years used in the reclassification from a Moderate area to 
a Serious area. The base year emissions inventory is a seasonal 
inventory, based on two meteorological episodes exemplifying the range 
of meteorological conditions that lead to exceedances of the 24-hour 
NAAQS. This is an appropriate temporal scope for a base year emissions 
inventory where anthropogenic exceedances of the 24-hour NAAQS are 
exclusively in winter.
    The emissions inventory is of actual emissions in 2013, as required 
in the PM2.5 SIP Requirements Rule and guidance.\17\ The 
emissions inventory also includes separate reporting for filterable and 
condensible PM2.5 for the relevant emissions sectors and SCC 
codes. The base year 2013 emissions inventory is based on methodologies 
used by the State and vetted by EPA in the Fairbanks Moderate Plan and 
applied to the new year 2013. Therefore, the inventory reports 
emissions of point sources consistent with the Air Emissions Reporting 
Rule (AERR) and contains the detail and data elements required by 40 
CFR part 51, subpart A. For these reasons, we are proposing to approve 
the 2013 base year emissions inventory in the Fairbanks Serious Plan as 
meeting the requirements of CAA section 172(c)(3) and 40 CFR 51.1008.
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    \17\ 40 CFR 51.1008(a)(1)(ii).
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B. PM2.5 Precursor Demonstration

1. Statutory and Regulatory Requirements
    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

[[Page 10515]]

contribute significantly to PM2.5 levels that exceed the 
NAAQS in the nonattainment area.\18\ 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.'' \19\ EPA has identified 
SO2, NOX, VOCs, and ammonia as precursors to the 
formation of PM2.5.\20\ Accordingly, the attainment plan 
requirements of subpart 4 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 the Act (e.g., CAA section 
189(e)).
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    \18\ 40 CFR 51.1006; See 81 FR 58010, August 24, 2016, at pp. 
58017-58020.
    \19\ CAA section 302(g).
    \20\ 81 FR 58010, August 24, 2016, at p. 58015.
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    A large number of chemical reactions, often non-linear in nature, 
can convert gaseous SO2, NOX, VOCs, and ammonia 
to PM2.5, making them precursors to PM2.5.\21\ 
Formation of secondary PM2.5 also depends on atmospheric 
conditions, including solar radiation, temperature, and relative 
humidity, and the interactions of precursors with particles and with 
cloud or fog droplets.\22\ According to the Fairbanks Serious Plan, 
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 Chapter III.D.7.8.1-7).
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    \21\ ``Air Quality Criteria for Particulate Matter'' (EPA/600/P-
99/002aF), EPA, October 2004, Ch. 3.
    \22\ ``Regulatory Impact Analysis for the Final Revisions to the 
National Ambient Air Quality Standards for Particulate Matter'' 
(EPA/452/R-12-005), EPA, December 2012), 2-1.
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    Section 189(e) of the Act requires that the control requirements 
for major stationary sources of direct PM10 \23\ also apply 
to major stationary sources of PM10 precursors, except where 
the Administrator determines that such sources do not contribute 
significantly to PM10 levels that exceed the standard in the 
area. Section 189(e) contains the only express exception to the control 
requirements under subpart 4 (e.g., requirements for 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 section 189(e) 
explicitly addresses only major stationary sources, EPA interprets the 
Act as authorizing it also to determine, under appropriate 
circumstances, that regulation of specific PM2.5 precursors 
from other source categories in a given nonattainment area is not 
necessary.\24\ For example, under 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,\25\ 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 levels in the nonattainment area.\26\
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    \23\ The 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.
    \24\ 81 FR 58010, August 24, 2016, at pp. 58018-58019.
    \25\ General Preamble, 57 FR 13498, April 16, 1992, at pp. 
13539-42.
    \26\ Courts have upheld this approach to the requirements of 
subpart 4 for PM10. See, e.g., Assoc. of Irritated 
Residents v. EPA, et al., 423 F.3d 989 (9th Cir. 2005).
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    Under the PM2.5 SIP Requirements Rule, a state may elect 
to submit to 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 in the area.\27\ If EPA 
determines that the contribution of the precursor to PM2.5 
levels in the area is not significant and approves the demonstration, 
the state is not required to control emissions of the relevant 
precursor from existing sources in the attainment plan.\28\
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    \27\ 40 CFR 51.1006(a)(1).
    \28\ 40 CFR 51.1006(a)(1).
---------------------------------------------------------------------------

    In addition, in May 2019, 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.\29\
---------------------------------------------------------------------------

    \29\ ``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.
---------------------------------------------------------------------------

    EPA evaluated the Fairbanks Serious 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 considered 
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.\30\
---------------------------------------------------------------------------

    \30\ 40 CFR 51.1006(a)(1)(i) and (ii).
---------------------------------------------------------------------------

2. Summary of State's Submission
    Alaska includes its PM2.5 precursor analysis in Chapter 
III.D.7.8, section 7.8.12, of the Fairbanks Serious Plan. The State 
provides both concentration-based and sensitivity-based analyses of 
precursor contributions to ambient PM2.5 concentrations in 
the Fairbanks PM2.5 Nonattainment Area. These analyses led 
the State to conclude that SO2 and ammonia emissions 
contribute significantly to ambient PM2.5 levels that exceed 
the PM2.5 NAAQS in the Fairbanks PM2.5 
Nonattainment Area, while NOX and VOCs do not contribute 
significantly to such exceedances, as discussed below. Consistent with 
this conclusion, the State focused the control strategy and attainment 
demonstration on sources of PM2.5, SO2, and 
ammonia emissions. Importantly, Alaska's precursor analysis did not 
address nonattainment NSR requirements. The State made the prior 
determination to regulate all four EPA-identified legal precursors to 
PM2.5 in the nonattainment NSR regulations applicable to the 
Fairbanks PM2.5 Nonattainment Area. The EPA approved 
Alaska's October 25, 2018, SIP revision as meeting the nonattainment 
NSR requirements triggered upon reclassification of the area to Serious 
(August 29, 2019, 84 FR 45419).
    Alaska applied a tiered approach to the precursor demonstrations in 
the Fairbanks PM2.5 Nonattainment Area. The tiered analysis 
included: (1) A concentration-based analysis of ambient data; (2) a 
concentration-based analysis using air quality modeling (zero-out); and 
(3) sensitivity-based analysis using air quality modeling. For the 
concentration-based analysis using

[[Page 10516]]

ambient data, Alaska assessed the contribution of SO2, 
NOX, and ammonia for all four monitor sites between 2011 and 
2015 on the highest concentration days. Alaska did not perform a 
concentration-based analysis using ambient data for VOCs. Through these 
analyses, Alaska identified that ammonia was a significant precursor in 
the Fairbanks PM2.5 Nonattainment Area.
    For the concentration-based analysis using air quality modeling, 
Alaska utilized version 4.7.1 of the Community Multiscale Air Quality 
(CMAQ) photochemical model. The modeling relied on many elements from 
the precursor analysis provided by the State in the Fairbanks Moderate 
Plan (e.g., meteorological inputs, emissions processing methods, nested 
modeling grids).
    Alaska performed modeling analyses using both the base year 
emissions inventory (2013) and the future year emissions inventory 
(2019) for VOCs and NOX. First, the State evaluated 
precursor significance using a zero-out approach that compared a 
baseline model run with a model run where a precursor's emissions were 
set to zero in order to determine the influence of that precursor on 
PM2.5 formation. For VOCs, Alaska performed a single 
analysis where it zeroed out all anthropogenic VOC emissions. For 
NOX, Alaska performed two zero-out analyses: One where all 
anthropogenic NOX emissions were zeroed out and one where 
only major stationary source NOX emissions were zeroed out. 
Next, Alaska further evaluated NOX precursor significance 
through a 75% sensitivity analysis. In this analysis, the State 
compared a baseline model run with a model run where all anthropogenic 
NOX emissions were reduced by 75%. Alaska concluded that 
these analyses showed that VOCs and NOX were not significant 
precursors in the Fairbanks PM2.5 Nonattainment Area.
    Alaska performed two SO2 precursor analyses using 
modeling elements from the Moderate Area Plan and updated baseline and 
future year emission inventories, as described previously in this 
preamble for the VOC and NOX modeling. Alaska first 
performed a zero-out analysis where it zeroed out major stationary 
source SO2 emissions. To address concerns about model 
underprediction of secondary sulfate, Alaska next performed an analysis 
that incorporated the base case model performance evaluation to 
estimate the impact of removing all major stationary source 
SO2 emissions. Based on these analyses, Alaska concluded 
that SO2 was a significant precursor in the Fairbanks 
PM2.5 Nonattainment Area.
    Additionally, on March 18, 2020, Alaska provided clarifications on 
the precursor analyses, included in the docket for this action. 
Included in these clarifications were further calculations projecting 
NOX significance at a 50% sensitivity level (i.e., the 
comparison of a baseline model run with a model run including a 50% 
reduction of all anthropogenic NOX emissions).
3. EPA's Evaluation and Proposed Action
    EPA has evaluated the State's precursor demonstration for the 
Serious area nonattainment plan consistent with the PM2.5 
SIP Requirements Rule and the recommendations in the PM2.5 
Precursor Guidance. Additional details of EPA's evaluation of Alaska's 
precursor PM2.5 analyses are included in a Technical Support 
Document included in the docket for this action.\31\ Based on this 
evaluation, EPA agrees that SO2 and ammonia emissions 
contribute significantly to ambient PM2.5 levels that exceed 
the 2006 PM2.5 NAAQS in the Fairbanks PM2.5 
Nonattainment Area and that SO2 and ammonia emission 
sources, therefore, remain subject to control requirements under 
subparts 1 and 4 of part D, title I of the Act.
---------------------------------------------------------------------------

    \31\ ``Review of Fairbanks Nonattainment Area Precursor 
Demonstrations for Volatile Organic Compounds and Nitrogen Oxides in 
the 2019 State Implementation Plan Submission.'' Nicole Briggs and 
Robert Kotchenruther, November 4, 2020.
---------------------------------------------------------------------------

    For the reasons provided in this preamble and further detailed in 
the Technical Support Document, EPA proposes to approve the State's 
demonstration that NOX and VOC emissions do not contribute 
significantly to ambient PM2.5 levels that exceed the 2006 
PM2.5 NAAQS in the Fairbanks PM2.5 Nonattainment 
Area. Our proposed approval of Alaska's precursor demonstration does 
not extend to nonattainment NSR requirements for the area. The State 
did not address the issue of precursors for purposes of nonattainment 
NSR requirements in the Fairbanks Serious Plan because Alaska 
previously determined that it was appropriate to regulate 
NOX, SO2, VOCs, and ammonia 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).
    Regarding the State's analytical approach, EPA proposes to find 
that the State used the appropriate methods and data to evaluate 
PM2.5 formation in the Fairbanks PM2.5 
Nonattainment Area from precursor emissions. Alaska began with 
concentration-based analyses for the precursors and proceeded with 
sensitivity-based analyses if necessary, which is an acceptable 
progression of analyses under the PM2.5 SIP Requirements 
Rule. The State utilized the appropriate threshold recommended in the 
EPA's guidance (1.5 [mu]g/m\3\) in evaluating the significance of 
precursor emissions to the formation of 24-hour PM2.5 and 
utilized data from all four monitors in the Fairbanks PM2.5 
Nonattainment Area.
    Regarding the results of the State's analysis, the concentration-
based modeling (Alaska's second tier precursor) analysis of VOC 
emissions demonstrates that anthropogenic VOCs have impacts on 
PM2.5 concentrations in the Fairbanks PM2.5 
Nonattainment Area that are well below the 1.5 [mu]g/m\3\ significance 
threshold. Therefore, we propose to concur with the State's conclusion 
that VOCs are not significant for PM2.5 formation in the 
Fairbanks PM2.5 Nonattainment Area.
    Further, we propose to find that the weight of evidence presented 
in the Fairbanks Serious Plan and Alaska's March 18, 2020, 
clarification document suggests that NOX emitted from all 
sources is an insignificant contributor to local PM2.5 
concentrations, based on the following evidence. First, the 
NOX 100% major stationary source reduction analysis 
demonstrated that NOX emissions are insignificant 
contributors to PM2.5 concentrations at the four monitor 
locations. Second, the NOX 75% all source reduction 
sensitivity analysis demonstrated that only 10% of the modeled days 
showed significant contributions of NOX to PM2.5 
concentrations at the Fairbanks monitors, and no days with significant 
contributions at the North Pole monitors. Third, the 75% all source 
reduction sensitivity analysis was conservative given that EPA guidance 
recommends evaluation of 30-70% reductions of the pollutant for 
analytical purposes.\32\ Lastly, Alaska's projected 50% reduction of 
NOX from all sources sensitivity analysis suggested there 
would be insignificant contributions

[[Page 10517]]

from NOX to PM2.5 concentrations on all modeled 
days at all monitors. Most of these days would have NOX 
contributions to PM2.5 concentrations well below the 1.5 
[mu]g/m\3\ significance threshold.
---------------------------------------------------------------------------

    \32\ ``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. Page 29.
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C. SIP Strengthening Measures

1. Summary of State's Submission
    In the October 25, 2018, November 28, 2018, and December 13, 2019 
submissions, Alaska requested EPA approval of specific changes to 
Alaska Administrative Code Title 18, Environmental Conservation, 
Chapter 50, Air Quality Control (18 AAC 50) State effective September 
15, 2018, January 8, 2019, and January 12, 2020. The requests included 
in the October 25, 2018 and November 28, 2018 SIP submissions (i.e., 
not the Fairbanks Serious Plan submission (December 13, 2019)) are 
noted below. The State adopted these regulatory revisions to strengthen 
the existing Alaska SIP and to meet the new Serious area planning 
requirements for BACM for certain source categories.
    This evaluation section discusses how the submitted rule revisions 
strengthen the current, Federally-approved SIP and why the EPA believes 
the rules are approvable. As such, our discussion focuses on the most 
recently submitted change to any particular rule provision. EPA is 
proposing to approve the submitted revisions to 18 AAC 50 and Volume 
III, Section III.D.7.12 of the State Air Quality Control Plan (the 
Fairbanks Emergency Episode Plan) as SIP strengthening and is not 
proposing to determine whether the submitted revisions satisfy, in 
whole or in part, the control strategy requirements in CAA section 189 
and 40 CFR 51.1010 nor the contingency measure requirements in CAA 
section 172(c)(9) and 40 CFR 51.1014.\33\
---------------------------------------------------------------------------

    \33\ As noted previously, EPA is proposing approval of the 
Fairbanks Emergency Episode Plan that was submitted on December 15, 
2020, and is included in the docket. A version of the Fairbanks 
Emergency Episode Plan was submitted as part of the Fairbanks 
Serious Plan on December 13, 2019, but this has been superseded by 
the version submitted December 15, 2020, as part of the revised 
plan.
---------------------------------------------------------------------------

2. EPA's Evaluation and Proposed Action
a. State Air Quality Control Plan
    In the submissions, Alaska repealed and readopted 18 AAC 50.030, 
the rule section into which all State air quality control provisions 
are adopted by reference. The revised version of the rule section 
contains two distinct paragraphs: Paragraph (a) adopts the State Air 
Quality Control Plan by reference into State rules; and paragraph (b) 
requires that sources subject to specific control measures and 
technologies in the State Air Quality Control Plan comply with those 
requirements. Alaska only submitted paragraph (b) to EPA for SIP 
approval.\34\
---------------------------------------------------------------------------

    \34\ Paragraph (a) of 18 AAC 50.030 is not appropriate for SIP 
approval because the EPA acts directly, as appropriate, on the 
specific provisions in the State Air Quality Control Plan that have 
been submitted by Alaska.
---------------------------------------------------------------------------

    Paragraph (b) makes clear that any source subject to Reasonably 
Available Control Technology (RACT), Best Available Control Measures 
(BACM), and Best Available Control Technology (BACT) under the State 
Air Quality Control Plan must comply with those applicable 
requirements. RACT, BACM, and BACT are terms defined in the Clean Air 
Act and in the EPA's implementing regulations, and Alaska has adopted 
these Federal definitions by reference into State regulation at 18 AAC 
50.990.\35\ Please see Section D.2.G in this preamble for further 
discussion.
---------------------------------------------------------------------------

    \35\ Alaska requested approval of this new regulation in the 
November 28, 2018, SIP submission. This submission is included in 
the docket of this action.
---------------------------------------------------------------------------

    The addition of paragraph (b) improves the enforceability of State-
adopted control measures, including those adopted for sources subject 
to RACT, BACM, and BACT in the Fairbanks PM2.5 Nonattainment 
Area. This enables Alaska to ensure that emission control measures as 
RACT, BACM, and BACT in the State Air Quality Control Plan are adopted 
and implemented. However, EPA's proposed approval of 18 AAC 50.030(b) 
does not constitute a proposed determination regarding whether the 
control measures the State identified as BACM or BACT in the Fairbanks 
Serious Plan satisfy, in whole or in part, the control strategy 
requirements in CAA section 189 and 40 CFR 51.1010. Therefore, we are 
proposing to approve and incorporate 18 AAC 50.030(b) by reference into 
the Alaska SIP.
b. Emission Standards for Solid Fuel-Fired Heating Devices
    Solid fuel-fired heating device visible emissions standards are 
found in 18 AAC 50.075. Alaska submitted revisions to paragraph (e) 
that clarify and strengthens the compliance requirements associated 
with PM2.5 air episode declaration that prohibits operation 
of solid fuel-fired heating devices. To comply, operators must withhold 
fuel from the device and ensure that burning has ceased within three 
hours of the effective time of the declaration. The changes to 
paragraph (e) make clear how to comply with such an air episode 
declaration and thus strengthen this rule section. Therefore, we 
propose to approve and incorporate by reference this change to 18 AAC 
50.075.
    Alaska also added paragraph (f) to 18 AAC 50.075. Paragraph (f) 
establishes a 20 percent opacity limit applicable in the Fairbanks 
PM2.5 Nonattainment Area, regardless of whether the State 
has called an air episode. This limit is similar to the 20 percent 
opacity limit established in Fairbanks North Star Borough ordinance 
2015-01, adopted into the Alaska SIP and approved by the EPA as part of 
the Fairbanks Moderate Plan on September 8, 2017 (82 FR 42457). We are 
deferring action on paragraph (f) because we intend to address it in a 
separate action.
c. Requirements for Wood Sellers
    The current version of 18 AAC 50.076 in the Alaska SIP requires 
commercial wood sellers serving the Fairbanks North Star Borough to 
register with Alaska Department of Environmental Conservation, if the 
Fairbanks PM2.5 Nonattainment Area is reclassified from 
Moderate to Serious. On May 10, 2017, the EPA reclassified the 
Fairbanks PM2.5 Nonattainment Area to Serious, effective 
June 9, 2017, therefore mandating wood seller registration. Because 
this provision has been triggered by the reclassification to Serious 
and is now in effect, Alaska removed the trigger language.
    The revisions to this rule section also require that registered 
commercial wood sellers serving the Fairbanks North Star Borough 
conduct moisture testing in accordance with this rule. Furthermore, the 
requirements become more stringent on October 1, 2021. Upon that date 
and going forward, commercial wood sellers serving the Fairbanks North 
Star Borough must ensure all dry wood is processed and monitored so as 
to remain dry, and may sell wet wood only if certain conditions 
designed to prevent burning of the wet wood are met. These conditions 
include minimum size requirements, moisture disclosure requirements, 
and a confirmation from the seller in writing that a buyer is capable 
of drying the wood by the next winter season. Wood sellers must 
document and report periodically on these practices and those that fail 
to comply will be subject to remedial training, a notice of violation, 
revocation of their registration, and/or enforcement action. Non-
commercial wood sellers are prohibited from selling wet wood in the 
Fairbanks PM2.5 Nonattainment Area. These rule revisions 
constitute more stringent

[[Page 10518]]

requirements for wood sellers, so we are approving these revisions as 
SIP strengthening.
    Consistent with our prior action on September 8, 2017, we propose 
to approve but not incorporate by reference the enforcement provision 
at paragraph (g)(11) to avoid conflict with the EPA's independent 
authorities (82 FR 42457).
d. Standards for Wood-Fired Heating Devices
    Wood-fired heating device standards are found in 18 AAC 50.077. The 
State submitted changes to this section that require removal of 
unapproved and uncertified wood-fired heating devices when residences 
are sold and leased, prevent the installation of wood-fired heating 
devices as the primary heat source in new construction, and restrict 
the sale and advertising of devices that do not meet the stricter 
standards. In addition, Alaska revised the regulations regarding non-
certified device removal upon sale of property and a mandatory dry wood 
compliance program. Prior to these revisions, these regulations became 
effective only upon an EPA determination that, among other things, the 
Fairbanks PM2.5 Nonattainment Area failed to attain the 2006 
PM2.5 NAAQS by the Moderate area attainment date. EPA made 
such a determination on May 10, 2017 (82 FR 21711). Accordingly, Alaska 
revised the regulation to remove the now-irrelevant contingency 
language and to make these regulations fully effective.
    Within the new wood-fired heating device standards, Alaska included 
a new rule section, 18 AAC 50.077(n) that adopted two contingency 
measures that will be triggered upon any of the determinations listed 
in 40 CFR 51.1014(a). 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. Control measures targeting the older EPA certified devices 
will provide additional emission reduction benefits beyond Alaska's 
current home heating control measures. Estimates of the projected 
emissions reductions attributable to these measures are included in the 
docket for this proposed action. These measures impose more stringent 
requirements on owners of solid-fuel heating devices in the Fairbanks 
PM2.5 Nonattainment Area, so we propose to approve these 
measures as SIP strengthening.
    Therefore, we propose to approve and incorporate 18 AAC 50.077(n) 
by reference into the Alaska SIP. As stated previously, however, we are 
not proposing to determine whether the submitted revisions to this rule 
satisfy, in whole or in part, the 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. Upon final approval, the 
Alaska SIP will incorporate 18 AAC 50.077 by reference, State effective 
January 8, 2020, except paragraphs (g) and (q). These paragraphs were 
not submitted for approval.
e. Limits on Sulfur Content of Fuel Oil
    Alaska submitted a new rule section, 18 AAC 50.078, designed to 
limit the sulfur content of fuel oil used in oil-fired equipment such 
as residential space heaters. This limit applies after September 1, 
2022. We propose to approve and incorporate 18 AAC 50.078(a) and (b) by 
reference into the Alaska SIP because these measures constitute more 
stringent standards on fuel sulfur content in the Fairbanks 
PM2.5 Nonattainment Area than what is currently in the SIP. 
In addition, 18 AAC 50.078(c) and 18 AAC 50.078(d) include new 
requirements for small area sources of PM2.5 including 
commercial charbroilers, commercial incinerators, commercial used oil 
burners, and commercial coffee roasters. We are deferring action on 18 
AAC 50.078(c) and 18 AAC 50.078(d).
f. Provisions for Coal-Fired Heating Devices
    Alaska added a new rule section, 18 AAC 50.079, to address 
emissions from coal-fired heating devices and submitted follow-up 
revisions to this rule section. The regulation at 18 AAC 50.079 
prohibits a person who owns or operates a coal-fired heating device 
from installing or reinstalling, supplying, selling, leasing, 
distributing, conveying, or advertising for sale within the 
nonattainment area. Coal-fired heating devices must be rendered 
inoperable when properties change hands or no later than December 31, 
2024.
    We note that this provision includes two exemptions, at paragraphs 
(d) and (e). Alaska submitted paragraph (d) for approval. This 
paragraph exempts devices that have passed approved wintertime emission 
source tests from certain requirements. The emission source test must 
be approved by ADEC, use a Federally approved method (40 CFR part 60, 
appendix A-3, Method 5), and the maximum emission rate for any 
individual test run does not exceed 18 g/hr of total particulate 
matter. We have reviewed the exemption under 18 AAC 50.079(d) and find 
it to be appropriately bounded, with specific criteria for an 
exemption. Alaska did not submit paragraph 18 AAC 50.079(e) for 
approval.
    In this action, we propose to approve and incorporate the submitted 
revisions to 18 AAC 50.079 by reference into the Alaska SIP. These 
revisions constitute more stringent standards for owners and operators 
of coal-fired heating devices than what is currently in the SIP. 
Accordingly, EPA proposes to approve these measures as SIP 
strengthening. Upon final approval, the Alaska SIP will include 18 AAC 
50.079, except paragraph (e).
g. Definitions
    The submissions revised 18 AAC 50.990 to update several air quality 
definitions. Alaska clarified the definition of ``particulate matter'' 
for the purpose of meeting the wood-fired heating device emissions 
standards established in 18 AAC 50.077.\36\ For this purpose, 
``particulate matter'' corresponds with the definition in 40 CFR 
60.531, subpart AAA Standards of Performance for New Residential Wood 
Heaters, and includes total particulate matter, as defined in that 
federal provision. Alaska DEC also revised the definition of ``solid 
fuel-fired heating device'' to make clear that certain dual-purpose 
centralized heat distribution systems are excluded from this 
definition.\37\
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    \36\ Alaska requested approval of this revised regulation in the 
November 28, 2018, SIP submission. This submission is included in 
the docket of this action.
    \37\ Alaska requested approval of this revised regulation in the 
November 28, 2018, SIP submission. This submission is included in 
the docket of this action.
---------------------------------------------------------------------------

    As discussed previously in this document, the submissions revised 
the Alaska SIP to adopt by reference the federal definitions of 
``RACT'', ``BACM'', and ``BACT'', as of July 1, 2017.\38\ ``RACT'' is 
defined as the federal definition in 40 CFR 51.100(o), ``BACM'' is 
defined as the definition in 40 CFR 51.1000, and ``BACT'' is defined as 
the definition in 40 CFR 52.21(b), except that it is limited to the 
nonattainment pollutant and its defined

[[Page 10519]]

precursors as they apply in the Fairbanks PM2.5 
Nonattainment Area.
---------------------------------------------------------------------------

    \38\ Alaska requested approval of this new regulation in the 
November 28, 2018, SIP submission. This submission is included in 
the docket of this action.
---------------------------------------------------------------------------

    Alaska DEC also added definitions for the terms ``catalytic 
oxidizer'', ``charbroiler'', ``chain-driven charbroiler'', and ``used 
oil'' to support the new information collection requirements for small 
area sources in 18 AAC 50.078.\39\
---------------------------------------------------------------------------

    \39\ Alaska requested approval of this new regulation in the 
Fairbanks Serious Plan submission.
---------------------------------------------------------------------------

    The added and revised definitions in 18 AAC 50.990 are consistent 
with Clean Air Act requirements, therefore, we propose to approve and 
incorporate the submitted revised definitions by reference into the 
Alaska SIP.
h. Emergency Episode Plan
    EPA approved the Fairbanks Emergency Episode Plan as meeting 
certain Moderate area control strategy requirements on September 8, 
2017 (82 FR 42457). EPA subsequently approved the plan for purposes of 
CAA section 110(a)(2)(G) requirements for the 2006 24-hour 
PM2.5 NAAQS (November 28, 2018, 83 FR 60769). Alaska revised 
the Fairbanks Emergency Episode Plan and submitted the updated plan as 
part of the Fairbanks Serious Plan submission on December 13, 2019. 
However, EPA did not act on the Fairbanks Serious Plan version, and 
Alaska has since revised the Emergency Episode Plan and submitted the 
updates for approval on December 15, 2020. EPA's most recent approval 
of the Fairbanks Emergency Episode Plan (Volume II, Section III.D.5.11) 
occurred on June 5, 2019 (84 FR 26019).
    As noted previously, on December 15, 2020, Alaska submitted an 
updated Fairbanks Emergency Episode Plan as it applies to the Fairbanks 
PM2.5 Nonattainment Area (Volume II, Section III.D.7.12). 
Generally, the submitted plan strengthens the solid fuel burning device 
curtailment program implemented via 18 AAC 50.075(e) and makes the 
control measures within this emissions source category more stringent. 
The submitted plan includes lower (more stringent) thresholds for air 
quality episodes and advisory/alerts, along with updated exceptions 
that have a limited duration and incentivize upgrading heating devices.
    In particular, Alaska revised the Air Quality Episode Thresholds 
and Exceptions used to declare the two-stage curtailment program. Both 
of the alert stages were lowered by 5 micrograms per cubic meter 
([mu]g/m\3\) in this submission. The Stage 1 Air Alert requires solid 
fuel burning devices to cease operation once PM2.5 
concentrations exceed 20 [mu]g/m\3\.\40\ The Emergency Episode Plan 
provides an exception during periods of power outage (Volume II, 
Section III.D.7.12, Table 7.12-1). Otherwise, operation of a solid fuel 
burning device during an air quality episode is prohibited unless the 
device qualifies for a temporary waiver. Operation of a solid fuel 
burning device during the Stage 1 Air Alert is allowed only if the 
device meets certain qualifications and conditions (see Volume II, 
Section III.D.7.12, Table 7.12-6 of the Fairbanks Serious Plan). 
Specifically, the waiver is limited in duration and requires older 
devices to be replaced in order to maintain the waiver. The Stage 2 Air 
Alert requires solid fuel burning devices to cease operation once 
PM2.5 concentrations rise above 30 micrograms per cubic 
meter ([mu]g/m\3\). Waivers for Stage 1 and Stage 2 Alerts are provided 
for a device owner or operator that qualifies for a No Other Adequate 
Source of Heat (NOASH) waiver (see Volume II, Section III.D.7.12, Table 
7.12-5 of the Fairbanks Serious Plan), but these waivers are also 
limited in duration and require older devices to be replaced in order 
to maintain the waiver. The Fairbanks Emergency Episode Plan included 
in the December 15, 2020, submission includes a control measure that 
will take effect upon an EPA finding under 40 CFR 51.1014(a) (``Stage 2 
Air Alert Contingency Measure''). If triggered, the control measure 
will lower the Stage 2 Air Alert threshold from 30 [mu]g/m\3\ to 25 
[mu]g/m\3\. See Table 1 below.
---------------------------------------------------------------------------

    \40\ According to the Emergency Episode Plan, ADEC air quality 
specialists use an air quality forecasting tool called the AQ Alert 
Model to issue forecasted curtailments by 2:00 p.m. local time. 
Before declaring a curtailment on the operation of solid fuel-fired 
heating devices, DEC reviews the relevant and available 
meteorological data, weather forecasts, affected area, strength of 
the inversion, and potential duration of the inversion. Other inputs 
include the afternoon forecast of dispersion conditions issued by 
the National Weather Service forecasting office in Fairbanks and the 
assessment by ADEC personnel of many factors based on their long-
standing experience in observing air quality in Fairbanks, including 
the rate of change in concentrations at the monitors and the 
location and movement of weather fronts seen in satellite photos. 
DEC sometimes calls an Alert that does not include a curtailment if 
weather conditions indicate a clearing prior to any impact of a 
curtailment taking effect.

                                      Table 1--Alaska's Table 7.12-1 Air Quality Episode Thresholds and Exceptions
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                       Stage 2 air alert  contingency
           Episode feature                       Stage 1 air alert                      Stage 2 air alert                          measure
--------------------------------------------------------------------------------------------------------------------------------------------------------
PM2.5 Threshold, micrograms per cubic  20...................................  30..................................  25.
 meter, ([mu]g/m\3\).
Exceptions During a Power Outage.....  Yes..................................  Yes.................................  Yes.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The Fairbanks Emergency Episode Plan also includes Air Advisories 
that allow Alaska to request voluntary curtailment actions prior to 
reaching PM2.5 concentrations that trigger the Air Alerts 
and mandatory curtailment requirements. Air Advisories are declared 
when PM2.5 concentrations exceed 15 [mu]g/m\3\ (24-hour 
rolling average). The Air Advisory was lowered by 5 [mu]g/m\3\ in this 
submission. See Table 2 below.

           Table 2--Alaska's Table 7.12-3 Advisory/Alert Level
------------------------------------------------------------------------
                                                        24-hour average
                                                             PM2.5
                        Type                             concentration
                                                          ([mu]g/m3)
------------------------------------------------------------------------
Advisory Alert......................................                 15
------------------------------------------------------------------------

    Alaska's revisions to the Fairbanks Emergency Episode Plan improve 
the State's ability to implement the solid fuel burning device 
curtailment program via 18 AAC 50.075(e) and make the related control 
measures more stringent. Specifically, the revised PM2.5 
thresholds for the two-stage program will result in reduced emissions 
from solid fuel burning devices, particularly during the winter months. 
Therefore, we propose to approve and incorporate Volume II, Section 
III.D.7.12 of the State Air Quality Control Plan by reference into the 
Alaska SIP. As stated earlier, EPA is proposing to approve the 
Fairbanks Emergency Episode Plan as SIP strengthening and is not 
proposing to determine whether the Plan satisfies, in whole or in part, 
the control strategy requirements in CAA section 189 and 40 CFR 51.1010 
or the contingency

[[Page 10520]]

measure requirements in CAA section 172(c)(9) and 40 CFR 51.1014.

IV. Summary of Proposed Action

    In this action, EPA is proposing to approve the submitted revisions 
to the Alaska SIP as meeting the following Serious Plan required 
elements for the 2006 24-hour PM2.5 NAAQS Fairbanks 
Nonattainment Area:
     The 2013 base year emissions inventory (CAA section 
172(c)(3); 40 CFR 51.1008(b)(1));
     The State's PM2.5 precursor demonstration for 
NOX and VOC emissions (CAA section 189(e) 40 CFR 
51.1006(a)); and
    The EPA is proposing to approve the submitted sections of the 
Alaska Air Quality Control Plan for the Fairbanks PM2.5 
Nonattainment Area, State effective January 8, 2020:
     Volume II Section III.D.7.06 and Volume III Section 
III.D.7.06 Emissions Inventory for purposes of the 2013 base year 
emissions inventory;
     Volume II Section III.D.7.08 Precursor Demonstration, for 
the purposes of NOX and VOC emissions as it relates to BACM/
BACT control measure requirements; and
    Further, the EPA is proposing to approve the submitted section of 
the Alaska Air Quality Control Plan for the Fairbanks PM2.5 
Nonattainment Area, State effective December 25, 2020:
     Volume II Section III.D.7.12, Emergency Episode Plan.\41\
---------------------------------------------------------------------------

    \41\ Submitted on December 15, 2020 and included in the docket. 
EPA is not at this time proposing to determine whether this updated 
planning chapter, in conjunction with the associated regulatory 
changes, meets other Serious area nonattainment plan requirements 
for the 2006 24-hour PM2.5 NAAQS in the Fairbanks 
PM2.5 Nonattainment Area.
---------------------------------------------------------------------------

    EPA is also proposing to approve and incorporate by reference 
submitted regulatory changes into the Alaska SIP. EPA is not at this 
time proposing to determine whether these provisions also meet other 
Serious area nonattainment plan requirements for the 2006 24-hour 
PM2.5 NAAQS in the Fairbanks PM2.5 Nonattainment 
Area. Upon final approval, the Alaska SIP will include:
     18 AAC 50.030, except (a), State effective January 12, 
2018;
     18 AAC 50.075, except (d)(2) and (f), State effective 
January 8, 2020;
     18 AAC 50.076, except (g)(11), State effective January 8, 
2020;
     18 AAC 50.077, except (g) and (q), State effective January 
8, 2020;
     18 AAC 50.078, except (c) and (d), State effective January 
8, 2020;
     18 AAC 50.079, except (e), State effective January 8, 
2020; and
     18 AAC 50.990(71), (138), (149), (150), (151), (152), 
(153), (154), and (155), State effective January 8, 2020.
    EPA is soliciting public comments on these proposed actions.

V. Incorporation by Reference

    In this document, 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, EPA is proposing to incorporate by 
reference the regulations described in Section IV of this preamble. 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 
INFORMATION CONTACT section of this preamble for more information).

VI. Statutory and Executive Order Reviews

    Under the Clean Air Act, the Administrator is required to approve a 
SIP submission that complies with the provisions of the Act and 
applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). 
Thus, in reviewing SIP submissions, EPA's role is to approve State 
choices, provided that they meet the criteria of the Clean Air Act. 
Accordingly, this proposed action merely proposes to approve State law 
as meeting Federal requirements and does not impose additional 
requirements beyond those imposed by State law. For that reason, this 
proposed action:
     Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Orders 
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 
2011);
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the Clean Air Act; and
     Does not provide the EPA with the discretionary authority 
to address, as appropriate, disproportionate human health or 
environmental effects, using practicable and legally permissible 
methods, under Executive Order 12898 (59 FR 7629, February 16, 1994).
    The SIP obligations discussed herein do not apply on any Indian 
reservation land or in any other area where EPA or an Indian tribe has 
demonstrated that a tribe has jurisdiction. This proposed action does 
not have tribal implications and will not impose substantial direct 
costs on tribal governments or preempt tribal law as specified by 
Executive Order 13175 (65 FR 67249, November 9, 2000).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, 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: February 9, 2021.
Michelle L. Pirzadeh,
Acting Regional Administrator, Region 10.
[FR Doc. 2021-03064 Filed 2-19-21; 8:45 am]
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