[Federal Register Volume 87, Number 10 (Friday, January 14, 2022)]
[Proposed Rules]
[Pages 2385-2389]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-00468]



40 CFR Part 52

[EPA-R03-OAR-2021-0834; FRL-9382-01-R3]

Air Plan Approval; Maryland; Philadelphia Area Base Year 
Inventory for the 2015 Ozone National Ambient Air Quality Standard

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.


SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve a state implementation plan (SIP) revision submitted by the 
State of Maryland. This revision consists of the base year inventory 
for the Maryland portion of the Philadelphia-Wilmington-Atlantic City, 
PA-NJ-MD-DE marginal nonattainment area (Philadelphia Area) for the 
2015 ozone national ambient air quality standard (NAAQS). This action 
is being taken under the Clean Air Act (CAA).

DATES: Written comments must be received on or before February 14, 

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R03-
OAR-2021-0834 at https://www.regulations.gov, or via email to 
[email protected]. For comments submitted at Regulations.gov, follow 
the online instructions for submitting comments. Once submitted, 
comments cannot be edited or removed from Regulations.gov. For either 
manner of submission, EPA may publish any comment received to its 
public docket. Do not submit electronically any information you 
consider to be confidential business information (CBI) or other 
information whose disclosure is restricted by statute. Multimedia 
submissions (audio, video, etc.) must be accompanied by a written 
comment. The written comment is considered the official comment and 
should include discussion of all points you wish to make. EPA will 
generally not consider comments or comment contents located outside of 
the primary submission (i.e., on the web, cloud, or other file sharing 
system). For additional submission methods, please contact the person 
identified in the FOR FURTHER INFORMATION CONTACT section. For the full 
EPA public comment policy, information about CBI or multimedia 
submissions, and general guidance on making effective comments, please 
visit https://www.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Adam Yarina, Planning & Implementation 
Branch (3AD30), Air & Radiation Division, U.S. Environmental Protection 
Agency, Region III, 1650 Arch Street, Philadelphia, Pennsylvania 19103. 
The telephone number is (215) 814-2103. Mr. Yarina can also be reached 
via electronic mail at [email protected].

SUPPLEMENTARY INFORMATION: On July 30, 2020, the Maryland Department of 
the Environment (MDE), on behalf of the State of Maryland, submitted a 
revision to the Maryland SIP entitled, ``2015 8-

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Hour Ozone NAAQS (0.070 ppm) Marginal Area State Implementation Plan 
for the Cecil County, MD Nonattainment Area, SIP #20-09.'' Cecil County 
comprises the Maryland portion of the Philadelphia Area. This SIP 
revision, referred to in this rulemaking action as the ``Cecil County 
base year inventory SIP,'' addresses the base year inventory 
requirement for the 2015 ozone NAAQS.

I. Background

    On October 1, 2015, EPA strengthened the 8-hour ozone NAAQS, 
lowering the level of the NAAQS from 0.075 ppm parts per million (ppm) 
to 0.070 ppm. 80 FR 65292 (October 26, 2015). Effective August 3, 2018, 
EPA designated the Philadelphia Area, which consists of Cecil County in 
Maryland and counties in Delaware, New Jersey, and Pennsylvania, as 
marginal nonattainment for the 2015 ozone NAAQS. 83 FR 25776 (June 4, 
2018). CAA section 182(a)(1) requires ozone nonattainment areas 
classified as marginal or above to submit a comprehensive, accurate, 
current inventory of actual emissions from all emissions sources in the 
nonattainment area, known as a ``base year inventory.'' The Cecil 
County base year inventory SIP addresses a base year inventory 
requirement for the Philadelphia Area.

II. Summary of SIP Revision and EPA Analysis

A. EPA Evaluation of the Cecil County Base Year Inventory SIP

    EPA's review of the Maryland's base year inventory SIP indicates 
that it meets the base year inventory requirements for the 2015 ozone 
NAAQS. As required by 40 CFR 51.1315(a), MDE selected 2017 for the base 
year inventory, which is consistent with the baseline year for the RFP 
because it is the year of the most recent triennial inventory. MDE 
included actual ozone season day emissions, pursuant to 40 CFR 
    EPA has prepared a technical support document (TSD) in support of 
this rulemaking. In that TSD, EPA reviewed the results, procedures, and 
methodologies for the SIP base year, and found them to be acceptable 
and developed in accordance with EPA's technical guidance. The TSD is 
available online at https://www.regulations.gov, Docket ID No. EPA-R03-

B. Base Year Inventory Requirements

    In EPA's December 6, 2018 (83 FR 62998) rulemaking, 
``Implementation of the 2015 National Ambient Air Quality Standards for 
Ozone: Nonattainment Area State Implementation Plan Requirements,'' 
known as the ``SIP Requirements Rule,'' EPA set out nonattainment area 
requirements for the 2015 ozone NAAQS. The SIP Requirements Rule 
established base year inventory requirement, which are codified at 40 
CFR 51.1315. 40 CFR 51.1315(a) requires each 2015 ozone nonattainment 
area to submit a base year inventory within 2 years of designation, 
i.e., by no later than August 3, 2020.
    40 CFR 51.1315(a) also requires that the inventory year be selected 
consistent with the baseline year for the reasonable further progress 
(RFP) plan as required by 40 CFR 51.1310(b), which states that the 
baseline emissions inventory shall be the emissions inventory for the 
most recent calendar year for which a complete triennial inventory is 
required to be submitted to the EPA under the provisions of subpart A 
of 40 CFR part 51, Air Emissions Reporting Requirements, 40 CFR 51.1 
through 50. The most recent triennial inventory year conducted for the 
National Emissions Inventory (NEI) pursuant to the Air Emissions 
Reporting Requirements (AERR) rule is 2017. 73 FR 76539 (December 17, 
2008). Maryland selected 2017 as their baseline emissions inventory 
year for RFP. This selection comports with EPA's implementation 
regulations for the 2015 ozone NAAQS because 2017 is the inventory 
year. 40 CFR 51.1310(b).\1\

    \1\ On January 29, 2021 the Court of Appeals for the D.C. 
Circuit issued its decision regarding multiple challenges to EPA's 
implementation rule for the 2015 ozone NAAQS which included, among 
other things, upholding this provision allowing states to use an 
alternative baseline year for RFP. Sierra Club v. EPA, 985 F.3d 1055 
(D.C. Cir.). The other provisions of EPA's ozone implantation rule 
at issue in the case are not relevant for this rulemaking.

    40 CFR 51.1315(c) requires emissions values included in the base 
year inventory to be actual ozone season day emissions as defined by 40 
CFR 51.1300(q), which states:

    Ozone season day emissions means an average day's emissions for 
a typical ozone season work weekday. The state shall select, subject 
to EPA approval, the particular month(s) in the ozone season and the 
day(s) in the work week to be represented, considering the 
conditions assumed in the development of RFP plans and/or emissions 
budgets for transportation conformity.

C. Cecil County Base Year Inventory SIP

    The Cecil County base year inventory SIP contains an explanation of 
MDE's 2017 base year emissions inventory for Cecil County (2017 Cecil 
County BYE) for stationary, non-point, non-road, and on-road 
anthropogenic sources, as well as biogenic sources, in the Cecil County 
Area. The Cecil County Area consists solely of Cecil County, MD. MDE 
estimated anthropogenic emissions for volatile organic compound (VOC), 
nitrogen oxide (NOX), and carbon monoxide (CO) for a typical 
ozone season workweek day.
    MDE developed the 2017 Cecil County BYE with the following source 
categories of anthropogenic emissions sources: Point, quasi-point, non-
point, non-road, on-road, and commercial marine vessels, airport, and 
railroad emissions sources (MAR). Appendix A of the Cecil County base 
year inventory SIP, 2017 Base Year SIP Emissions Inventory 
Methodologies (Appendix A), sets out the methodologies MDE used to 
develop its base year inventory.
1. Point Sources
    Point sources are larger sources that are located at a fixed, 
stationary location. As defined by the AERR in 40 CFR 51.50, point 
sources are large, stationary (non-mobile), identifiable sources of 
emissions that release pollutants into the atmosphere. A point source 
is a facility that is a major source under 40 CFR part 70 for one or 
more of the pollutants for which reporting is required by 40 CFR 
51.15(a)(1). These point sources can be associated with a single point 
or group of points in space. Examples of point source emissions 
categories include power plants, industrial boilers, petroleum 
refineries, cement plants, and other industrial plants.
    As stated in Appendix A, for the 2017 Cecil County BYE, MDE defined 
a point source located within a designated ozone nonattainment area as 
a stationary commercial or industrial facility that operations and 
emits more than 10 tons per year (tpy) of VOC; or 25 tons per year of 
NOX; or a 100 tpy of CO, sulfur oxides (SOX), 
particulate matter with an aerodynamic diameter less than 10 
micrometers (PM10), diameter less than 2.5 micrometers 
(PM2.5), and total suspended particulates (TSP).
    In Appendix A, MDE explains that it used several methods of source 
identification to ensure the point source inventory is as complete as 
possible. MDE's primary data source is its permitting program, and 
MDE's compliance program identifies other point sources through 
facility inspections and investigations. In addition, facilities are 
required by Maryland's emissions statement regulations, Code of 
Maryland Regulations (COMAR) and to certify 
the air

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emissions for the past calendar year. The certified emissions are used 
for inventory and planning purposes.
    MDE developed the point source data for the 2017 base year 
inventory. The point source inventory contains emissions for electric 
generating units (EGUs) and Non-EGU sources in the nonattainment area. 
EPA guidance for emissions inventory development provides that ozone 
season day emissions are used for the base year inventory for the 
nonattainment area. MDE developed their 2017 inventory by using 
emissions directly reported to the agency by facilities as required by 
Maryland air quality regulations. These emissions are also reported to 
EPA, and after going through EPA's quality assurance (QA) and quality 
control (QC) process, are included in EPA's National Emissions 
Inventory (NEI). The emissions for this base year can be found in EPA's 
2017 NEI.\2\

    \2\ Technical Support Document (TSD) for the Base Year Inventory 
Submitted with the 2015 8-Hour Ozone NAAQS Marginal Area State 
Implementation Plan for the Baltimore, MD Nonattainment Area, 
included in the docket for this rulemaking available online at 
https://www.regulations.gov, Docket ID: EPA-R03-OAR-2021-0834.

2. Quasi-Point Sources
    MDE defines quasi-point sources as that are generally considered 
part of the non-point or non-road emissions sectors but are included in 
the point source emissions inventory for a particular reason. Such 
reasons include Federal guidance, as in the case of certain airports, 
or to facilitate future general conformity determinations, as in the 
case of military bases, ports, and other similar facilities. EPA has 
reviewed the source categories included in the quasi-point sources and 
has found this to be a reasonable approach to handle these sources. MDE 
has not identified any quasi-point sources in Cecil County.
3. Non-Point Sources
    Non-point sources are also called ``area sources.'' These sources 
collectively represent individual sources of emissions that have not 
been inventoried as either specific point or mobile sources. These 
individual sources treated collectively as non-point sources are 
typically too small, numerous, or difficult to inventory using the 
methods for the other classes of sources.
    Non-point sources that MDE evaluated for the 2017 Cecil County BYE 
include petroleum distribution losses (e.g., tank truck unloading and 
auto refueling), stationary source solvent application (e.g., dry 
cleaners, auto refinishing), bioprocess emissions sources (e.g., 
bakeries, breweries, wineries, distilleries), catastrophic/accidental 
releases (e.g., oil spills and leaking underground storage tanks), 
solid waste disposal, treatment, and recovery (e.g., incineration, open 
burning), small stationary source fossil fuel use (e.g., small utility 
boilers, wood combustion, commercial cooking), fugitive sources (e.g., 
construction activity and unpaved roads), fire sources (e.g., 
agricultural burning and vehicle fires), and ammonia sources (e.g., 
agricultural livestock production operations). Appendix A sets out the 
methodologies MDE used to estimate emissions for each of these non-
point source categories. These methods are consistent with the most 
recent EPA emission inventory guidance.
4. Non-Road
    Non-road mobile sources are also called ``off-highway'' mobile 
sources. These are defined as a non-road engine or non-road vehicle. As 
per 40 CFR 51.50, a non-road engine is an internal combustion engine 
(including the fuel system) that is not used in an on-road motor 
vehicle or a vehicle used solely for competition, or that is not 
affected by sections 111 or 202 of the CAA. Also defined by 40 CFR 
51.50, a non-road vehicle (rather than engine) is a vehicle that is run 
by a non-road engine and that is not an on-road motor vehicle or a 
vehicle used solely for competition. Examples of non-road mobile 
sources include airport ground support equipment, agricultural and 
construction equipment powered by an internal combustion engine, and 
lawn and garden engines and equipment.
    As explained in Appendix A, consistent with EPA's Emission 
Inventory Guidance for Implementation of Ozone and Particulate Matter 
National Ambient Air Quality Standards and Regional Haze Regulations, 
MDE used the most current version of EPA's NONROAD2008a model, which is 
incorporated into EPA's Motor Vehicle Emission Simulator (MOVES) model, 
specifically MOVES2014a, to develop the inventory for non-road mobile 
sources. The NONROAD2008a model includes more than 80 basic and 260 
specific types of non-road equipment (e.g., agricultural, airport 
support, commercial, construction, industrial, recreational vehicles, 
recreational watercraft, lawn and garden, railway maintenance, etc.) 
and further stratifies equipment types by horsepower rating. Fuel types 
include gasoline, diesel, compressed natural gas (CNG), and liquefied 
petroleum gas (LPG).
    Marine Vessels, Airport, Railroad Locomotives (MAR) Sources are a 
non-road subcategory. MDE states in its Cecil County base year 
inventory SIP that, for MAR sources, MDE calculated emissions by 
collecting data directly from surveyed sources, or activity from state 
and federal reporting agencies. To develop the commercial marine 
vehicle emissions for the base year, Maryland used EPA's 2016 beta 
modeling platform. This platform was used because it provided the most 
recent descriptions and methodologies for calculation of marine vessel 
emissions. To estimate emissions for aircraft, Maryland used airport 
activity statistics from the Federal Aviation Agency (FAA), landing and 
takeoff cycle information from the Maryland Aviation Administration, 
and statewide survey information for landing and takeoffs, engine type, 
location, and usage data. Railroad emission estimates were developed 
using activity and fuel consumption estimates collected from the rail 
companies and proportioned to each county by the amount of track miles 
each company utilized in a county. MDE applied EPA emission factors 
using EPA guidance and methodologies or the best engineering method. 
These methods of calculating emissions are consistent with the most 
recent EPA emission inventory guidance.\3\ Details of the development 
of emissions for these sources along with other non-road model sources 
are provided in Appendix A.

    \3\ Emission Inventory Guidance for Implementation of Ozone and 
Particulate Matter National Ambient Air Quality Standards (NAAQS) 
and Regional Haze Regulations, Page 130, included in the docket for 
this rulemaking available online at https://www.regulations.gov, 
Docket ID: EPA-R03-OAR-2021-0834 PG 130.

5. On-Road Sources
    On-road mobile sources are also called ``highway mobile sources.'' 
These sources are the motor vehicles (e.g., automobiles, buses, trucks) 
traveling on local and highway roads. On-road mobile source emission 
estimates should utilize the latest recommended on-road mobile source 
models; currently, that means the EPA's MOVES model for all states 
except California.
    The MOVES model estimates emissions from vehicle exhaust and from 
mobile source evaporative emissions, both of which must be included in 
the inventory. Volatile hydrocarbons evaporate from fuel systems while 
a vehicle is refueling, parked, or driving. Evaporative processes 
differ from exhaust emissions because they don't directly involve 
combustion, which is the main process driving exhaust emissions.

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    As stated in Appendix A, MDE used EPA's MOVES2014a model to 
estimate the 2017 annual emissions as well as 2017 daily emissions from 
on-road vehicles and total energy consumption in Maryland. Emissions 
were estimated based on emission factors and vehicle activity. Emission 
factors for vehicles were based on vehicle type (e.g., passenger cars, 
passenger trucks), vehicle age, and the vehicle's operating modes. 
Operating modes for running, start, and idle emissions are included in 
MOVES. The emission factors varied over a range of conditions, such as 
the ambient air temperature, speed, traffic conditions, road types, 
road topography, etc. The generated emission factors were then 
multiplied by the appropriate vehicle miles traveled (VMT) to estimate 
    To estimate the rate at which emissions are being generated and to 
calculate VMT, MDE examined its road network and fleet to estimate 
vehicle activity. For the annual inventories, this was done for each of 
the twelve months in 2017 and aggregated for the entire year. MDE used 
computer models to perform these calculations by simulating the travel 
of vehicles on the Maryland's roadway system.
    EPA has reviewed the results, procedures, and methodologies for the 
SIP base year, as well as comparing the inventory with previously QA/QC 
data in EPA's 2017 NEI for any data discrepancies and found none. EPA 
has therefore determined the base year inventory to be acceptable and 
developed in accordance with EPA's technical guidance.
6. Biogenic Emissions
    MDE also inventoried biogenic emissions, which are not included in 
the anthropogenic total. Biogenic emissions come from natural sources, 
including vegetation, soils, volcanic emissions, lightning, and sea 
salt. They need to be accounted for in photochemical grid models, as 
most types are widespread and ubiquitous contributors to background 
formation of ozone. However, they are not included in the RFP baseline.
    Biogenic emissions are typically computed using a model which 
utilizes spatial information on vegetation and land use and 
environmental conditions of temperature and solar radiation. The model 
inputs are typically horizontally allocated (gridded) data, and the 
outputs are gridded biogenic emissions which can then be speciated and 
utilized as input to photochemical grid models.
    In Appendix A, MDE explains that it used the data files created and 
made available by EPA. MDE computed biogenic emissions with a modified 
version of EPA's Biogenic Emission Inventory System (BEIS) model that 
utilized county land use data from EPA's land use inventory and 
temperature and cloud cover data from the National Weather Service. 
This method is acceptable under EPA's emission inventory guidance.
7. Emissions Summary
    The Cecil County base year inventory SIP contains a summary of 2017 
ozone season day emissions by source category, which is presented in 
Table 1 in this document. MDE notes that the biogenic emissions are 
taken from EPA's NEI 2014 database. Total biogenic emissions for July 
2014 were divided by 31 days to develop average ozone season day 
emissions for each jurisdiction in the region and then added together 
to develop the regional total.

                                     Table 1--2017 Cecil County BYE Summary
                                           [Tons per ozone season day]
                         Source category                                VOC             NOX             CO
Point...........................................................           0.415           1.604           0.472
Quasi-Point.....................................................           0.000           0.000           0.000
Non-Point.......................................................           2.729           0.333           1.272
Non-Road........................................................           2.315           1.019          15.546
MAR.............................................................           0.063           1.463           0.259
On-Road Mobile..................................................           1.468           4.460          19.110
    Anthropogenic Total.........................................           6.990           8.879          36.660
Biogenic........................................................          33.776           0.555           4.079

III. Proposed Action

    EPA's review of this material indicates the Cecil County base year 
inventory SIP meets the base year inventory requirement for the 2015 
ozone NAAQS for Maryland's portion of the Philadelphia Area, which 
consists solely of Cecil County, Maryland. Therefore. EPA is proposing 
to approve the Cecil County base year inventory SIP, which was 
submitted on July 30, 2020. EPA is soliciting public comments on the 
issues discussed in this document. These comments will be considered 
before taking final action.

IV. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP 
submission that complies with the provisions of the CAA 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 CAA. Accordingly, this 
action merely approves state law as meeting Federal requirements and 
does not impose additional requirements beyond those imposed by state 
law. For that reason, this 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, 
     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);

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     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 CAA; and
     Does not provide 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).
    In addition, this proposed rulemaking, proposing to approve 
Maryland's portion of the Philadelphia nonattainment area base year 
inventory for the 2015 ozone NAAQS, does not have tribal implications 
as specified by Executive Order 13175 (65 FR 67249, November 9, 2000), 
because the SIP is not approved to apply in Indian country located in 
the State, and EPA notes that it will not impose substantial direct 
costs on tribal governments or preempt tribal law.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Carbon monoxide, 
Incorporation by reference, Intergovernmental relations, Ozone, 
Reporting and recordkeeping requirements, Volatile organic compounds.

    Dated: January 3, 2022
Diana Esher,
Acting Regional Administrator, Region III.
[FR Doc. 2022-00468 Filed 1-13-22; 8:45 am]