29222 Federal Register / Vol. 86, No. 103 / Tuesday, June 1, 2021 / Proposed Rules 

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 CAA; and 

• Does not provide the EPA with the 

discretionary authority to address 

disproportionate human health or 

environmental effects with practical, 

appropriate, and legally permissible 

methods under Executive Order 12898 

(59 FR 7629, February 16, 1994). 

In addition, this proposed action does 

not have Tribal implications as 

specified by Executive Order 13175 (65 

FR 67249, November 9, 2000), because 

the SIP obligations discussed herein do 

not apply to Indian Tribes and thus this 

proposed action will not impose 

substantial direct costs on Tribal 

governments or preempt Tribal law. 

Nonetheless, the EPA intends to notify 

the Cocopah and Fort Yuma (Quechan) 

tribes, which have lands within the 

Yuma NAA. 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Incorporation by 

reference, Intergovernmental relations, 

Particulate Matter, Pollution. 

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

Dated: May 24, 2021. 

Deborah Jordan, 

Acting Regional Administrator, Region IX. 

[FR Doc. 2021–11395 Filed 5–28–21; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R03–OAR–2021–0017; FRL–10023– 

69–Region 3] 

Air Plan Approval; Maryland; Baltimore 

Area Base Year Inventory for the 2015 

Ozone National Ambient Air Quality 

Standards 

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 Baltimore, Maryland 

marginal nonattainment area (Baltimore 

Area) for the 2015 ozone national 

ambient air quality standards (NAAQS). 

This action is being taken under the 

Clean Air Act (CAA). 

DATES: Written comments must be 

received on or before July 1, 2021. 

ADDRESSES: Submit your comments, 

identified by Docket ID No. EPA–R03– 

OAR–2021–0017 at https://

www.regulations.gov, or via email to 

David.Talley@epa.gov. For comments 

submitted at Regulations.gov, follow the 

online instructions for submitting 

comments. Once submitted, comments 

cannot be edited or removed from 

Regulations.gov. 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: 

Serena Nichols, 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) 

814–2053. Ms. Nichols can also be 

reached via electronic mail at 

Nichols.Serena@epa.gov. 

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- 

Hour Ozone NAAQS (0.070 ppm) 

Marginal Area State Implementation 

Plan for the Baltimore, MD 

Nonattainment Area, SIP #20–08.’’ This 

SIP revision, referred to in this 

rulemaking action as the ‘‘Baltimore 

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 Baltimore Area, 

consisting of Anne Arundel, Baltimore, 

Carroll, Harford, and Howard Counties 

and the City of Baltimore, all in 

Maryland, 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 Baltimore base 

year inventory SIP addresses a base year 

inventory requirement for the Baltimore 

Area. 

II. Summary of SIP Revision and EPA 

Analysis 

A. EPA’s Evaluation of the Baltimore 

Base Year Inventory SIP 

EPA’s review of Maryland’s base year 

inventory SIP for the Baltimore Area 

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 reasonable 

further progress (RFP) plan because it is 

the year of the most recent triennial 

inventory. MDE included actual ozone 

season emissions, pursuant to 40 CFR 

51.1315(c). 

EPA prepared a Technical Support 

Document (TSD) in support of this 

rulemaking. In that TSD, EPA reviewed 

the results, procedures, and 


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1On 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, No. 15–1465 (D.C. Cir.) 

(mandate not yet issued). The other provisions of 

EPA’s ozone implantation rule at issue in the case 

are not relevant for this rulemaking. 

2The Appendix A—2017 Base Year SIP Emission 

Inventory Methodologies, submitted with the 2015 

8-Hour Ozone NAAQS Marginal Area State 

Implementation Plan for the Baltimore, MD 

Nonattainment Area is included in the docket for 

this rulemaking available online at https://

www.regulations.gov, Docket ID: EPA–R03–OAR– 

2021–0017. 

3The 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– 

2021–0017. 

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 http://

www.regulations.gov, Docket ID No. 

EPA–R03–OAR–2021–0017. 

B. Base Year Inventory Requirements 

In EPA’s December 6, 2018 (83 FR 

62998) rule, ‘‘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 were 

codified at 40 CFR 51.1315. As required 

by 40 CFR 51.1315(a), 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. 

Also, 40 CFR 51.1315(a) requires that 

the inventory year be selected consistent 

with the baseline year for the 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 

EPA under the provisions of subpart A 

of 40 CFR 51, Air Emissions Reporting 

Requirements, 40 CFR 51.1–50. 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 Further, 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 

sates: 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. Baltimore Base Year Inventory SIP 

The Baltimore base year inventory SIP 

contains an explanation of MDE’s 2017 

base year emissions inventory for 

Baltimore (2017 Baltimore BYE) for 

stationary, non-point, non-road, and onroad anthropogenic sources, as well as 

biogenic sources, in the Baltimore Area. 

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 Baltimore 

BYE with the following source 

categories of anthropogenic emissions 

sources: Point, quasi-point, non-point, 

non-road, on-road, biogenic, and 

commercial marine vessels, airport, and 

railroad emissions sources (MAR). 

Appendix A of the Baltimore 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.2

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 

Baltimore 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. MDE’s compliance 

program identifies other point sources 

though facility inspections and 

investigations. In addition, facilities are 

required by Maryland’s emissions 

statement regulations, Code of Maryland 

Regulations (COMAR) 26.11.01.05–1 

and 26.11.02.19D to certify the air 

emissions for the past calendar year. 

The certified emissions are used for 

inventory and planning purposes. 

MDE’s Air and Radiation Management 

Administration (ARMA) developed the 

point source data for the 2017 base year 

inventory. The point source inventory 

contains emissions for electric 

generating units (EGU) and Non-EGU 

sources in the nonattainment area 

(NAA). EPA guidance for emissions 

inventory development provides that 

ozone season day emissions are used for 

the base year inventory for the NAA. 

ARMA 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.3

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. In Appendix A, MDE states that 

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. 


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4Emission 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–2021–0017 PG 130. 

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 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 Baltimore 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 (bakeries, breweries, wineries, 

distilleries), catastrophic/accidental 

releases (e.g., oil spills), solid waste 

disposal treatment, and recovery (e.g., 

open burning), small stationary source 

fossil fuel use (e.g., small utility boilers), 

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 Mobile Sources 

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 NAAQS 

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 

and further stratifies equipment types 

by horsepower rating. Fuel types 

include gasoline, diesel, compressed 

natural gas (CNG), and liquefied 

petroleum gas (LPG). 

5. Marine Vessels, Airport, Railroad 

Locomotives (MAR) Sources 

MAR is a non-road sub-category. MDE 

states in its Baltimore 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 

Administration (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.4 Details of 

the development of emissions for these 

sources along with other non-road 

model sources are provided in 

Appendix A of Maryland’s July 30, 2020 

submittal. 

6. On-Road Mobile 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 sources should be estimated by 

the latest recommended on-road mobile 

source models. Currently, that means 

EPA’s MOVES model for all states but 

California. 

In addition to emissions from 

vehicles’ exhaust, the MOVES model 

estimates evaporative emissions for 

mobile sources, which must be included 

in the inventory. Volatile hydrocarbons 

evaporate from the fuel system 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. 

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 such as 

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 

emission. 

In order to estimate both 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’d 

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. 

7. 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 


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5Emission Inventory Guidance for 

Implementation of Ozone and Particulate Matter 

National Ambient Air Quality Standards (NAAQS) 

and Regional Haze Regulations, Page 100, included 

in the docket for this rulemaking available online 

at https://www.regulations.gov, Docket ID: EPA– 

R03–OAR–2021–0017 PG 130. 

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.5

8. Emissions Summary 

The Baltimore base year inventory SIP 

contains a summary of 2017 ozone 

season day emissions by source 

category, which is presented in Table 1 

of this document. Tables 2 through 7 of 

this document present the 2017 

Baltimore BYE by source category and 

county. In the Baltimore base year 

inventory SIP, MDE notes that the 

biogenic emissions in Table 1 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 Baltimore Area and 

then added together to develop the 

Baltimore Area total. 

TABLE 1—2017 BALTIMORE BYE SUMMARY

[Tons per ozone season day] 

Source category VOC NOX CO 

Point ......................................................................................................................................................... 5.729 47.530 18.902 

Quasi-Point .............................................................................................................................................. 1.310 7.274 6.549 

Non-Point ................................................................................................................................................. 72.233 10.931 26.954 

Non-Road ................................................................................................................................................. 21.314 13.164 330.888 

MAR ......................................................................................................................................................... 0.930 7.440 3.848 

On-Road Mobile ....................................................................................................................................... 25.860 53.720 365.010 

Anthropogenic Total ......................................................................................................................... 127.379 140.060 752.152 

Biogenic ................................................................................................................................................... 227.640 2.740 24.550 

TABLE 2—2017 BALTIMORE BYE POINT SOURCE EMISSIONS

[Tons per ozone season day] 

County name VOC NOX CO 

Anne Arundel County .............................................................................................................................. 0.885 13.079 5.523 

Baltimore County ..................................................................................................................................... 0.876 11.531 2.788 

Carroll County .......................................................................................................................................... 0.390 8.342 5.568 

Harford County ........................................................................................................................................ 0.471 3.110 0.422 

Howard County ........................................................................................................................................ 1.036 1.266 0.920 

Baltimore City .......................................................................................................................................... 2.070 10.202 3.682 

Baltimore Area Total ......................................................................................................................... 5.729 47.530 18.900 

TABLE 3—2017 BALTIMORE BYE QUASI-POINT SOURCE EMISSIONS

[Tons per ozone season day] 

County name VOC NOX CO 

Anne Arundel County .............................................................................................................................. 0.793 4.009 4.554 

Baltimore County .....................................................................................................................................

Carroll County ..........................................................................................................................................

Harford County ........................................................................................................................................ 0.451 2.451 1.634 

Howard County ........................................................................................................................................

Baltimore City .......................................................................................................................................... 0.066 0.815 0.361 

Baltimore Area Total ......................................................................................................................... 1.310 7.274 6.549 

TABLE 4—2017 BALTIMORE BYE NON-POINT SOURCE EMISSIONS

[Tons per ozone season day] 

County name VOC NOX CO 

Anne Arundel County .............................................................................................................................. 16.532 2.090 2.836 

Baltimore County ..................................................................................................................................... 20.168 3.200 4.206 

Carroll County .......................................................................................................................................... 4.810 0.595 2.922 


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TABLE 4—2017 BALTIMORE BYE NON-POINT SOURCE EMISSIONS—Continued 

[Tons per ozone season day] 

County name VOC NOX CO 

Harford County ........................................................................................................................................ 9.111 1.007 12.685 

Howard County ........................................................................................................................................ 7.745 1.375 1.617 

Baltimore City .......................................................................................................................................... 13.867 2.665 2.689 

Baltimore Area Total ......................................................................................................................... 72.233 10.931 26.954 

TABLE 5—2017 BALTIMORE BYE NON-ROAD SOURCE EMISSIONS

[Tons per ozone season day] 

County name VOC NOX CO 

Anne Arundel County .............................................................................................................................. 5.818 3.263 80.901 

Baltimore County ..................................................................................................................................... 6.421 4.725 102.577 

Carroll County .......................................................................................................................................... 1.572 0.980 26.043 

Harford County ........................................................................................................................................ 2.645 1.590 30.234 

Howard County ........................................................................................................................................ 2.712 1.500 53.191 

Baltimore City .......................................................................................................................................... 2.145 1.107 37.943 

Baltimore Area Total ......................................................................................................................... 21.314 13.164 330.888 

TABLE 6—2017 BALTIMORE BYE MAR SOURCE EMISSIONS

[Tons per ozone season day] 

County name VOC NOX CO 

Anne Arundel County .............................................................................................................................. 0.113 1.623 0.776 

Baltimore County ..................................................................................................................................... 0.634 2.277 1.833 

Carroll County .......................................................................................................................................... 0.027 0.188 0.497 

Harford County ........................................................................................................................................ 0.031 0.469 0.321 

Howard County ........................................................................................................................................ 0.013 0.302 0.075 

Baltimore City * ........................................................................................................................................ 0.112 2.582 0.348 

Baltimore Area Total ......................................................................................................................... 0.930 7.440 3.848 

* Emissions from marine vessels at the Port of Baltimore are included here. 

TABLE 7—2017 BALTIMORE BYE MOBILE SOURCE EMISSIONS

[Tons per ozone season day] 

County name VOC NOX CO 

Anne Arundel County .............................................................................................................................. 6.17 12.33 85.88 

Baltimore County ..................................................................................................................................... 8.12 17.72 117.58 

Carroll County .......................................................................................................................................... 2.13 3.10 21.86 

Harford County ........................................................................................................................................ 2.73 5.26 35.31 

Howard County ........................................................................................................................................ 3.12 8.21 54.20 

Baltimore City .......................................................................................................................................... 3.60 7.10 50.18 

Baltimore Area Total ......................................................................................................................... 25.86 53.72 365.01 

III. Proposed Action 

EPA’s review of this material 

indicates the Baltimore base year 

inventory SIP meets the base year 

inventory requirement for the 2015 

ozone NAAQS for the Baltimore Area. 

Therefore, EPA is proposing to approve 

the Baltimore 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, 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 


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Federal Register / Vol. 86, No. 103 / Tuesday, June 1, 2021 / Proposed Rules 29227 

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 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 base year inventory SIP 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, Nitrogen dioxide, Volatile 

organic compounds. 

Dated: May 19, 2021. 

Diana Esher, 

Acting Regional Administrator, Region III. 

[FR Doc. 2021–11441 Filed 5–28–21; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R09–OAR–2021–0333; FRL–10023– 

88–Region 9] 

Air Plan Limited Approval and Limited 

Disapproval, California; Mojave Desert 

Air Quality Management District 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is proposing a limited 

approval and limited disapproval of 

revisions to the Mojave Desert Air 

Quality Management District’s 

(MDAQMD or District) portion of the 

California State Implementation Plan 

(SIP). This revision concerns oxides of 

nitrogen (NOX) emissions from 

stationary internal combustion engines. 

We are proposing action on a local rule 

that regulates these emission sources 

under the Clean Air Act (CAA or the 

Act). We are taking comments on this 

proposal and plan to follow with a final 

action. 

DATES: Comments must be received on 

or before July 1, 2021. 

ADDRESSES: Submit your comments, 

identified by Docket ID No. EPA–R09– 

OAR–2021–0333 at http://

www.regulations.gov. For comments 

submitted at Regulations.gov, follow the 

online instructions for submitting 

comments. Once submitted, comments 

cannot be edited or removed from 

Regulations.gov. The EPA may publish 

any comment received to its public 

docket. Do not submit electronically any 

information you consider to be 

Confidential Business Information (CBI) 

or other information whose disclosure is 

restricted by statute. Multimedia 

submissions (audio, video, etc.) must be 

accompanied by a written comment. 

The written comment is considered the 

official comment and should include 

discussion of all points you wish to 

make. The EPA will generally not 

consider comments or comment 

contents located outside of the primary 

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

other file sharing system). For 

additional submission methods, please 

contact the person identified in the FOR

FURTHER INFORMATION CONTACT section. 

For the full EPA public comment policy, 

information about CBI or multimedia 

submissions, and general guidance on 

making effective comments, please visit 

http://www.epa.gov/dockets/ 

commenting-epa-dockets. If you need 

assistance in a language other than 

English or if you are a person with 

disabilities who needs a reasonable 

accommodation at no cost to you, please 

contact the person identified in the FOR

FURTHER INFORMATION CONTACT section. 

FOR FURTHER INFORMATION CONTACT: 

Kevin Gong, EPA Region IX, 75 

Hawthorne St., San Francisco, CA 

94105. By phone: (415) 972–3073 or by 

email at gong.kevin@epa.gov. 

SUPPLEMENTARY INFORMATION: 

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

and ‘‘our’’ refer to the EPA. 

Table of Contents 

I. The State’s Submittal 

A. What rule did the State submit? 

B. Are there other versions of this rule? 

C. What is the purpose of the submitted 

rule revision? 

II. The EPA’s Evaluation and Action 

A. How is the EPA evaluating the rule? 

B. Does the rule meet the evaluation 

criteria? 

C. What are the rule deficiencies? 

D. Proposed Action and Public Comment 

III. Incorporation by Reference 

IV. Statutory and Executive Order Reviews 

I. The State’s Submittal 

A. What rule did the State submit? 

Table 1 lists the rule addressed by this 

proposal with the dates that it was 

adopted by the MDAQMD and 

submitted by the California Air 

Resources Board. 

TABLE 1—SUBMITTED RULE

Rule No. Rule title Amended Submitted 

1160 ............... Internal Combustion Engines ...................................................................................................... 01/22/2018 05/23/2018 

On November 23, 2018 the submittal 

for MDAQMD Rule 1160 was deemed by 

operation of law to meet the 

completeness criteria in 40 CFR part 51 

Appendix V, which must be met before 

formal EPA review. 

B. Are there other versions of this rule? 

We approved an earlier version of 

Rule 1160 into the SIP on November 1, 

1996 (61 FR 56470). 


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