Rule2022-25134
Control of Air Pollution From Aircraft Engines: Emission Standards and Test Procedures
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
November 23, 2022
Effective
December 23, 2022
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is finalizing particulate matter (PM) emission standards and test procedures applicable to certain classes of engines used by civil subsonic jet airplanes (engines with rated output of greater than 26.7 kilonewtons (kN)) to replace the existing smoke standard for those engines. The EPA is adopting these standards under our authority in the Clean Air Act (CAA). These standards and test procedures are equivalent to the engine standards adopted by the United Nations' International Civil Aviation Organization (ICAO) in 2017 and 2020 and will apply to both new type design aircraft engines and in-production aircraft engines. The EPA, as well as the U.S. Federal Aviation Administration (FAA), actively participated in the ICAO proceedings in which the ICAO requirements were developed. These standards reflect the importance of the control of PM emissions and U.S. efforts to secure the highest practicable degree of uniformity in aviation regulations and standards. Additionally, the EPA is migrating, modernizing, and streamlining the existing regulations into a new part in the Code of Federal Regulations. As part of this update, the EPA is also aligning with ICAO by applying the smoke number standards to engines less than or equal to 26.7 kilonewtons rated output used on supersonic airplanes.
Full Text
<html>
<head>
<title>Federal Register, Volume 87 Issue 225 (Wednesday, November 23, 2022)</title>
</head>
<body><pre>
[Federal Register Volume 87, Number 225 (Wednesday, November 23, 2022)]
[Rules and Regulations]
[Pages 72312-72357]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2022-25134]
[[Page 72311]]
Vol. 87
Wednesday,
No. 225
November 23, 2022
Part III
Environmental Protection Agency
-----------------------------------------------------------------------
40 CFR Parts 9, 87, 1030, et al.
Control of Air Pollution From Aircraft Engines: Emission Standards and
Test Procedures; Final Rule
Federal Register / Vol. 87, No. 225 / Wednesday, November 23, 2022 /
Rules and Regulations
[[Page 72312]]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 9, 87, 1030, and 1031
[EPA-HQ-OAR-2019-0660; FRL-7558-02-OAR]
RIN 2060-AU69
Control of Air Pollution From Aircraft Engines: Emission
Standards and Test Procedures
AGENCY: Environmental Protection Agency (EPA)
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: The Environmental Protection Agency (EPA) is finalizing
particulate matter (PM) emission standards and test procedures
applicable to certain classes of engines used by civil subsonic jet
airplanes (engines with rated output of greater than 26.7 kilonewtons
(kN)) to replace the existing smoke standard for those engines. The EPA
is adopting these standards under our authority in the Clean Air Act
(CAA). These standards and test procedures are equivalent to the engine
standards adopted by the United Nations' International Civil Aviation
Organization (ICAO) in 2017 and 2020 and will apply to both new type
design aircraft engines and in-production aircraft engines. The EPA, as
well as the U.S. Federal Aviation Administration (FAA), actively
participated in the ICAO proceedings in which the ICAO requirements
were developed. These standards reflect the importance of the control
of PM emissions and U.S. efforts to secure the highest practicable
degree of uniformity in aviation regulations and standards.
Additionally, the EPA is migrating, modernizing, and streamlining the
existing regulations into a new part in the Code of Federal
Regulations. As part of this update, the EPA is also aligning with ICAO
by applying the smoke number standards to engines less than or equal to
26.7 kilonewtons rated output used on supersonic airplanes.
DATES: This final rule is effective on December 23, 2022. The
incorporation by reference of certain material listed in this rule is
approved by the Director of the Federal Register as of December 23,
2022.
ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-HQ-OAR-2019-0660. All documents in the docket are
listed on the <a href="http://www.regulations.gov">www.regulations.gov</a> website. Although listed in the
index, some information is not publicly available, e.g., confidential
business information or other information whose disclosure is
restricted by statute. Certain other material, such as copyrighted
material is not placed on the internet and will be publicly available
only in hard copy form. Publicly available docket materials are
available either electronically through <a href="http://www.regulations.gov">www.regulations.gov</a> or in hard
copy at the EPA Docket Center, WJC West Building, Room 3334, 1301
Constitution Ave. NW, Washington, DC. The Docket Center's hours of
operations are 8:30 a.m.-4:30 p.m., Monday-Friday (except Federal
Holidays). For further information on the EPA Docket Center services
and the current status, see: <a href="https://www.epa.gov/dockets">https://www.epa.gov/dockets</a>.
FOR FURTHER INFORMATION CONTACT: Bryan Manning, Office of
Transportation and Air Quality, Assessment and Standards Division
(ASD), Environmental Protection Agency, 2000 Traverwood Drive, Ann
Arbor, MI 48105; telephone number: (734) 214-4832; email address:
<a href="/cdn-cgi/l/email-protection#9ff2fef1f1f6f1f8b1fdede6fef1dffaeffeb1f8f0e9"><span class="__cf_email__" data-cfemail="a3cec2cdcdcacdc48dc1d1dac2cde3c6d3c28dc4ccd5">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. General Information
A. Does this action apply to me?
B. Executive Summary
C. EPA Future Work on Aircraft Engine PM Standards Beyond the
Scope of This Final Rule
D. Judicial Review, Administrative Reconsideration, and
Severability
II. Introduction: Context for This Action
A. The EPA Statutory Authority and Responsibilities Under the
Clean Air Act
B. The Role of the United States in International Aircraft
Agreements
C. The Relationship Between the EPA's Regulation of Aircraft
Engine Emissions and International Standards
III. Particulate Matter Impacts on Air Quality and Health
A. Background on Particulate Matter
B. Health Effects of Particulate Matter
C. Environmental Effects of Particulate Matter
D. Near-Source Impacts on Air Quality and Public Health
E. Contribution of Aircraft Emissions to PM in Selected Areas
F. Other Pollutants Emitted by Aircraft
G. Environmental Justice
IV. Details of the Rule
A. PM Mass Standards for Aircraft Engines
B. PM Number Standards for Aircraft Engines
C. PM Mass Concentration Standard for Aircraft Engines
D. Test and Measurement Procedures
E. Annual Reporting Requirement
F. Response to Key Comments
V. Aggregate PM Inventory Methodology and Impacts
A. Aircraft Engine PM Emissions Modeling Methodologies
B. PM Emission Inventory
C. Projected Reductions in PM Emissions
VI. Technological Feasibility and Economic Impacts
A. Market Considerations
B. Conceptual Framework for Technology
C. Technological Feasibility
D. Costs Associated With the Rule
E. Summary of Benefits and Costs
VII. Technical Amendments
A. Migration of Regulatory Text to New Part
B. Deletion of Unnecessary Provisions
C. Other Technical Amendments and Minor Changes
VIII. Statutory Authority and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
B. Paperwork Reduction Act (PRA)
C. Regulatory Flexibility Act (RFA)
D. Unfunded Mandates Reform Act (UMRA)
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
G. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution or Use
I. National Technology Transfer and Advancement Act (NTTAA) and
1 CFR Part 51
J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
K. Congressional Review Act
I. General Information
A. Does this action apply to me?
This action will potentially affect companies that design and/or
manufacture civil subsonic jet aircraft engines with a rated output of
greater than 26.7 kN and those that design and/or manufacture civil jet
engines with a rated output at or below 26.7 kN for use on supersonic
airplanes. These potentially affected entities include the following:
------------------------------------------------------------------------
Examples of
Category NAICS code \a\ potentially affected
entities
------------------------------------------------------------------------
Industry....................... 336412 Manufacturers of new
aircraft engines.
------------------------------------------------------------------------
\a\ North American Industry Classification System (NAICS).
[[Page 72313]]
This table lists the types of entities that the EPA is now aware
could potentially be affected by this action. Other types of entities
not listed in the table could also be regulated. To determine whether
your activities are regulated by this action, you should carefully
examine the relevant applicability criteria in 40 CFR parts 87, 1030,
and 1031. If you have any questions regarding the applicability of this
action to a particular entity, consult the person listed in the
preceding FOR FURTHER INFORMATION CONTACT section.
For consistency purposes across the U.S. Code of Federal
Regulations (CFR), common definitions for the words ``airplane,''
``aircraft,'' ``aircraft engine,'' and ``civil aircraft'' are found at
14 CFR 1.1 and are used as appropriate throughout this new regulation
under 40 CFR parts 87, 1030, and 1031.
B. Executive Summary
1. Summary of the Major Provisions of the Regulatory Action
The EPA is regulating PM emissions from certain aircraft engines
through the adoption of domestic PM regulations that match the ICAO PM
standards, which will be implemented and enforced in the United States.
The covered engines are subsonic turbofan and turbojet aircraft engines
with rated output (maximum thrust available for takeoff) of greater
than 26.7 kN. These aircraft engines are used by civil subsonic jet
airplanes generally for the purpose of commercial passenger and freight
aircraft, as well as larger business jets. The EPA is adopting three
different forms of PM standards: a PM mass standard in milligrams per
kilonewton (mg/kN), a PM number standard in number of particles per
kilonewton (#/kN), and a PM mass concentration standard in micrograms
per cubic meter ([micro]g/m\3\). The applicable dates and coverage of
these standards vary, as described in the following paragraphs, and
more fully in sections IV.A, IV.B, and IV.C respectively.
First, the EPA is finalizing PM engine emission standards, in the
form of both PM mass (mg/kN) and PM number (#/kN), for both new type
design and in-production covered engines. The standards for in-
production engines apply to those engines that are manufactured on or
after January 1, 2023. The standards for new type designs apply to
those engines whose initial type certification application is submitted
on or after January 1, 2023. The in-production standards have different
emission levels limits than the standards for new type designs. The
different emission limits for new type designs and in-production
engines depend on the rated output of the engines. Compliance with the
PM mass and number standards will be done in accordance with the
standard landing and take-off (LTO) test cycle, which is currently used
for demonstrating compliance with gaseous emission standards (oxides of
nitrogen (NO<INF>X</INF>), hydrocarbons (HC), and carbon monoxide (CO)
standards) for the covered engines.
Second, the EPA is adopting a PM engine emission standard in the
form of maximum mass concentration ([micro]g/m\3\) for covered engines
manufactured on or after January 1, 2023.\1\ Compliance with the PM
mass concentration standard will be done using the same test data that
is developed to demonstrate compliance with the LTO-based PM mass and
number standards. The PM mass concentration standard applies to the
highest concentration of PM measured across the engine operating thrust
range, not just at one of the four LTO thrust settings.
---------------------------------------------------------------------------
\1\ The implementation date for ICAO's PM maximum mass
concentration standards is on or after January 1, 2020. The PM
maximum mass concentration standards finalized in this action will
have an implementation date of January 1, 2023 (instead of January
1, 2020).
---------------------------------------------------------------------------
The PM mass concentration standard was developed by ICAO to
provide, through a PM mass measurement, the equivalent smoke opacity or
visibility control as afforded by the existing smoke number standard
for the covered engines. Thus, the EPA is no longer applying the
existing smoke number standard for new engines that will be subject to
the PM mass concentration standard after January 1, 2023, but the EPA
is maintaining smoke number standards for new engines not covered by
the PM mass concentration standard (e.g., in-production aircraft
turbofan and turbojet engines with rated output less than or equal to
26.7 kN) and for engines already manufactured. This approach will
essentially change the existing standard for covered engines from being
based on a smoke measurement to a PM measurement.
Third, the EPA is finalizing testing and measurement procedures for
the PM emission standards and various updates to the existing gaseous
exhaust emissions test procedures. These test procedure provisions will
implement the recent additions and amendments to the ICAO's
regulations, which are codified in ICAO Annex 16, Volume II. As we have
historically done, we are incorporating these test procedure additions
and amendments to the ICAO Annex 16, Volume II into our regulations by
reference.
The aircraft engine PM standards, test procedures and associated
regulatory requirements are equivalent to the international PM
standards and test procedures adopted by ICAO in 2017 and 2020 and
promulgated in Annex 16, Volume II.\2\ The United States and other
member States of ICAO, as well as the world's aircraft engine
manufacturers and other interested stakeholders, participated in the
deliberations leading up to ICAO's adoption of the international
aircraft engine PM emission standards.
---------------------------------------------------------------------------
\2\ ICAO, 2017: Aircraft Engine Emissions, International
Standards and Recommended Practices, Environmental Protection, Annex
16, Volume II, Fourth Edition, July 2017. Available at <a href="https://www.icao.int/publications/catalogue/cat_2022_en.pdf">https://www.icao.int/publications/catalogue/cat_2022_en.pdf</a> (last accessed
October 31, 2022). The ICAO Annex 16 Volume II is found on page 17
of the ICAO Products & Services Catalog, English Edition of the 2022
catalog, and it is copyright protected; Order No. AN16-2. The ICAO
Annex 16, Volume II, Fourth Edition, includes Amendment 10 of
January 1, 2021. Amendment 10 is also found on page 17 of this ICAO
catalog, and it is copyright protected; Order No. AN 16-2/E/12.
---------------------------------------------------------------------------
In addition to the PM standards just discussed, the EPA is
migrating most of the existing aircraft engine emissions regulations
from 40 CFR part 87 to a new 40 CFR part 1031, and all the aircraft
engine standards and requirements are specified in this new 40 CFR part
1031. Along with this migration, the EPA is restructuring the
regulations to allow for better ease of use and allow for more
efficient future updates. The EPA is also deleting some unnecessary
definitions and regulatory provisions. Finally, the EPA is adopting
several other minor technical amendments to the regulations, including
applying smoke number standards to engines of less than or equal to
26.7 kilonewtons (kN) rated output used in supersonic airplanes.
2. Purpose of the Regulatory Action
In developing these standards, the EPA took into consideration the
Agency's legal authority and the explicit requirements under CAA
section 231, including those relating to safety, noise, lead time and
costs. The EPA further considered the importance of controlling PM
emissions, international harmonization of aviation requirements, and
the international nature of the aircraft industry and air travel. In
addition, the EPA gave significant weight to the United States' treaty
obligations under the Chicago Convention, as discussed in Section II.B,
in determining the need for and appropriate levels of PM standards.
These considerations led the EPA to conclude that adopting standards
for PM emissions from certain classes of
[[Page 72314]]
covered aircraft engines that are equivalent in scope, stringency, and
effective date to the PM standards adopted by ICAO are appropriate at
this time.
One of the core functions of ICAO is to adopt Standards and
Recommended Practices on a wide range of aviation-related matters,
including aircraft emissions. As a member State of ICAO, the United
States actively participates in the development of new environmental
standards, within ICAO's Committee on Aviation Environmental Protection
(CAEP), including the PM standards adopted by ICAO in both 2017 and
2020. Due to the international nature of the aviation industry, there
is an advantage to working within ICAO to secure the highest
practicable degree of uniformity in international aviation regulations
and standards. Uniformity in international aviation regulations and
standards is a goal of the Chicago Convention, because it ensures that
passengers and the public can expect similar levels of protection for
safety and human health and the environment regardless of manufacturer,
airline, or point of origin of a flight. Further, it helps reduce
barriers in the global aviation market, benefiting both U.S. aircraft
engine manufacturers and consumers.
When developing new emission standards, ICAO/CAEP seeks to capture
the technological advances made in the control of emissions through the
adoption of anti-backsliding standards reflecting the current state of
technology. The PM standards that the EPA is adopting were developed
using this approach. Thus, the adoption of these aviation standards
into U.S. law will simultaneously prevent aircraft engine PM levels
from increasing beyond their current levels, align U.S. domestic
standards with the ICAO standards for international harmonization, and
meet the United States' treaty obligations under the Chicago
Convention.
These standards will also allow U.S. manufacturers of covered
aircraft engines to remain competitive in the global marketplace (as
described in Section IV). In the absence of U.S. standards implementing
the ICAO aircraft engine PM emission standards, U.S. civil aircraft
engine manufacturers could be forced to seek PM emissions certification
from an aviation certification authority of another country (not the
FAA) to market and operate their aircraft engines internationally. U.S.
manufacturers could be at a significant disadvantage if the United
States fails to adopt standards that are at least as stringent as the
ICAO standards for PM emissions. The ICAO aircraft engine PM emission
standards have been adopted by other ICAO member states that certify
aircraft engines.\3\ The action to adopt in the U.S. PM standards that
match the ICAO standards will help ensure international consistency and
acceptance of U.S.-manufactured engines worldwide.
---------------------------------------------------------------------------
\3\ Aside from the FAA in the United States, the only other
civil aviation authorities that routinely certify airplane engines
are Transport Canada and the European Union Aviation Safety Agency,
both of which have already adopted the ICAO airplane engine
particulate matter emission standards.
---------------------------------------------------------------------------
3. Environmental Justice
The EPA defines environmental justice as the fair treatment and
meaningful involvement of all people regardless of race, color,
national origin, or income with respect to the development,
implementation, and enforcement of environmental laws, regulations, and
policies. Section III.G discusses the potential environmental justice
concerns associated with exposure to aircraft PM near airports.
Studies have reported that many communities in close proximity to
airports are disproportionately represented by people of color and low-
income populations (as described in Section III.G). Separate from this
rulemaking, the EPA is conducting an analysis of communities residing
near airports where jet aircraft operate to more fully understand
disproportionately high and adverse human health or environmental
effects on people of color, low-income populations, and/or Indigenous
peoples. The results of this analysis could help inform additional
policies to reduce pollution in communities living in close proximity
to airports.
As described in Section V.C, while newer aircraft engines typically
have significantly lower emissions than existing aircraft engines, the
standards in this final rule are technology-following to align with
ICAO's standards and are not expected to, in and of themselves, result
in further reductions in PM from these engines. Therefore, we do not
anticipate the standards to result in an improvement in air quality for
those who live near airports where these aircraft operate.
C. EPA Future Work on Aircraft Engine PM Standards Beyond the Scope of
This Final Rule
While the EPA believes that adopting PM standards that match those
developed and adopted by ICAO is the proper course of action in this
final rule, the EPA views the standards adopted in this action as just
one appropriate step in our efforts to control PM emissions from
aircraft engines. Consistent with our statutory authority, which
directs the EPA to issue, and permits the EPA to revise, standards
``from time to time,'' CAA section 231(a)(2)(A) and (a)(3), after
consultation with the FAA (CAA section 231(a)(2)(B)(i)), the EPA views
our regulation of aircraft PM emissions as a long-term process, with
the potential for successive standards of increasing stringency. Future
stringencies may include technology-forcing standards, where
appropriate, provided that such standards do not significantly increase
noise and adversely affect safety in accordance with CAA section
231(a)(2)(B)(ii). The EPA intends to continue to assess available
emission control technologies and associated lead times, so that if the
EPA were to pursue more stringent standards in the future, the EPA
would provide the necessary time to permit the development and
application of the requisite technology--giving appropriate
consideration to the cost of compliance within such period.
The EPA continues to believe that ICAO is the most appropriate
venue in which to undertake such work. To that end, the U.S. delegation
to ICAO/CAEP, with significant input from EPA, developed a position
paper to the CAEP/12 meeting in February 2022.\4\ In this paper, the
United States proposed several topics for CAEP to consider for future
work on emissions items. Among the U.S. proposals was a call to update
the PM standards beyond those already adopted by CAEP that would
reflect best available technologies for future, to-be-developed,
standards. The United States also proposed work to develop an updated
metric to improve the effectiveness of future NO<INF>X</INF> emission
standards, as well as an integrated standards-setting process to
simultaneously update both PM and NO<INF>X</INF> standards for aircraft
engines given the strong interdependency between engine NO<INF>X</INF>
and PM levels.\5\ The EPA also advocated for improved modeling
techniques that would better reflect the costs and emission reductions
and better inform decision making around proposed CAEP emission
standard levels.
---------------------------------------------------------------------------
\4\ U.S. EPA, Mueller, J. Memorandum to Docket ID No. EPA-HQ-
OAR-2019-0660, ``United States Position Papers to CAEP/12 Meeting,''
August 19, 2022.
\5\ In this context, the metric is the form of the standard (in
this case, mass of pollutant per unit of thrust), as well as the
form of the regulatory limit line and any correlating parameters
included. In the case of aircraft engine NO<INF>X</INF>, the
regulatory limit line is a function of engine overall pressure
ratio.
---------------------------------------------------------------------------
[[Page 72315]]
CAEP did not accept the U.S. request to work on updated aircraft
engine NO<INF>X</INF> and PM standards during the current CAEP/13 cycle
due to concerns that the resources needed for such work would
negatively impact efforts to update the international airplane
CO<INF>2</INF> and noise standards. However, work on an improved
NO<INF>X</INF> metric was approved and is underway this CAEP cycle,
with an understanding that it is laying the groundwork for a potential
update of the NO<INF>X</INF> and PM standards during the next CAEP
cycle.\6\ Further, improving the cost and emission reduction modeling
methodology has been agreed to as a work item for this CAEP cycle. The
EPA is actively working within CAEP on both these efforts, and the EPA
will continue to advocate for efforts in CAEP that will result in the
development of future PM emission standards which reflect best
available technologies.
---------------------------------------------------------------------------
\6\ ICAO, 2022: Committee on Aviation Environmental Protection
(CAEP), Report of the Twelfth Meeting, Montreal, February 7-17,
2022, Doc 10176, CAEP/12.
---------------------------------------------------------------------------
D. Judicial Review, Administrative Reconsideration, and Severability
This final action is ``nationally applicable'' within the meaning
of CAA section 307(b)(1) because it is expressly listed in the section
(i.e., ``any standard under section [231] of this title''). Under CAA
section 307(b)(1), petitions for judicial review of this action must be
filed in the U.S. Court of Appeals for the District of Columbia Circuit
within 60 days from the date this final action is published in the
Federal Register. Filing a petition for reconsideration by the
Administrator of this final action does not affect the finality of the
action for the purposes of judicial review, nor does it extend the time
within which a petition for judicial review must be filed and shall not
postpone the effectiveness of such rule or action. Under CAA section
307(b)(2), the requirements established by this final rule may not be
challenged separately in any civil or criminal proceedings brought by
the EPA to enforce the requirements.
CAA section 307(d)(7)(B) further provides that only an objection to
a rule or procedure which was raised with reasonable specificity during
the period for public comment (including any public hearing) may be
raised during judicial review. This section also provides a mechanism
for the EPA to reconsider the rule if the person raising an objection
can demonstrate to the Administrator that it was impracticable to raise
such objection within the period for public comment or if the grounds
for such objection arose after the period for public comment (but
within the time specified for judicial review) and if such objection is
of central relevance to the outcome of the rule. Any person seeking to
make such a demonstration should submit a Petition for Reconsideration
to the Office of the Administrator, U.S. EPA, Room 3000, WJC South
Building, 1200 Pennsylvania Ave. NW, Washington, DC 20460, with a copy
to both the person listed in the FOR FURTHER INFORMATION CONTACT
section, and the Associate General Counsel for the Air and Radiation
Law Office, Office of General Counsel (Mail Code 2344A), U.S. EPA, 1200
Pennsylvania Ave. NW, Washington, DC 20460. In addition, the EPA
requests that an electronic copy of the Petition for Reconsideration
also be sent to the person listed in the FOR FURTHER INFORMATION
CONTACT section.
The following portions of this rulemaking are mutually severable
from each other: (1) the PM mass concentration standard in Section
IV.C; (2) the PM mass and number standards in sections IV.A and IV.B;
(3) the test and measurement procedures in Section IV.D; (4) the
reporting requirements in Section IV.E; (5) those changes to 40 CFR
parts 87 and 1031 described in Section VII that are not intended solely
to implement the new PM standards; and (6) the changes to 40 CFR part
1030 described in Section VII.C.\7\ The PM mass concentration standard
and the PM mass and number standards serve different purposes, as
described in more detail in Section IV. The reporting requirements
(including those for PM) in Section IV.E predate this final rule as
they were established by a prior Information Collection Request and are
simply being added to the CFR in this action for the convenience of the
entity required to provide a production report. Similarly, while the
test and measurement procedures in Section IV.D will be used in
determining compliance with the new PM standards, they are not
dependent on the PM standards, and they are also required to be used to
comply with the reporting requirements separate from the actual PM
standards. The regulatory migration and other technical amendments in
Section VII are not related to the implementation of the new PM
standards. If any of the portions of this rule the EPA has identified
as mutually severable from each other are vacated by a reviewing court,
the EPA intends for the portions of this rule which are not vacated by
a reviewing court to remain effective, and would only take action to
remove the portions of the rule which are vacated from the CFR, leaving
the other portions of the rule in effect.\8\ Finally, if a reviewing
court were to vacate the PM mass concentration standard in Section
IV.C, the EPA intends to reinstate the smoke number standard contained
in 40 CFR 1031.60(a)(5) for engines with a rated output of greater than
26.7 kN, such that the smoke number standard would go back into effect
for those engines.
---------------------------------------------------------------------------
\7\ Certain portions may also be internally severable.
\8\ The EPA considers those sections of regulatory text which
are included only to implement the new PM standards to all be within
40 CFR part 1031. Specifically, the regulatory text solely related
to implementing the PM mass concentration standard is contained in
Sec. Sec. 1031.30(a)(2)(ii), 1031.60(a)(6), and 1031.130(c)(1)(v),
as well as the phrase ``before January 1, 2023'' in Sec.
1031.60(a)(5), while the regulatory text solely related to
implementing the PM mass and number standards is contained in
Sec. Sec. 1031.30(a)(2)(iii) and (iv), 1031.60(b), and
1031.130(c)(1)(vi) and (vii). All other regulatory changes are
severable from the PM standards and are intended to remain in effect
if any of the PM standards were to be set aside by a reviewing
court.
---------------------------------------------------------------------------
II. Introduction: Context for This Action
The EPA has been regulating PM emissions from aircraft engines
since the 1970s when the first smoke number standards were adopted.
This section provides context for the final rule, which adopts three PM
standards for aircraft engines (a PM mass standard, a PM number
standard, and a PM mass concentration standard). This section includes
a description of the EPA's statutory authority, the U.S. role in ICAO
and developing international emission standards, and the relationship
between the U.S. standards and the ICAO international standards.
A. The EPA's Statutory Authority and Responsibilities Under the Clean
Air Act
CAA section 231(a)(2)(A) directs the Administrator of the EPA to,
from time to time, propose aircraft engine emission standards
applicable to the emission of any air pollutant from classes of
aircraft engines which in his or her judgment causes or contributes to
air pollution that may reasonably be anticipated to endanger public
health or welfare.\9\ CAA section 231(a)(2)(B) directs the EPA to
consult with the Administrator of the Federal Aviation Administration
(FAA) on such standards, and it prohibits the EPA from changing
aircraft emission standards if such a change would significantly
increase noise and adversely affect safety.\10\ CAA section 231(a)(3)
provides that after we provide notice and an opportunity for a public
hearing on standards, the Administrator shall issue such standards
``with such modifications as he deems
[[Page 72316]]
appropriate.'' \11\ In addition, under CAA section 231(b) the EPA is
required to ensure, in consultation with the U.S. Department of
Transportation (DOT), that the effective date of any standard provides
the necessary time to permit the development and application of the
requisite technology, giving appropriate consideration to the cost of
compliance within such period.\12\
---------------------------------------------------------------------------
\9\ 42 U.S.C. 7571(a)(2)(A).
\10\ 42 U.S.C. 7571(a)(2)(B)(i)-(ii).
\11\ 42 U.S.C. 7571(a)(3).
\12\ 42 U.S.C. 7571(b).
---------------------------------------------------------------------------
Consistent with its longstanding approach \13\ and the District of
Columbia (D.C.) Circuit precedent,\14\ the EPA interprets its authority
under CAA section 231 as providing the Administrator wide discretion in
determining what standards are appropriate, after consideration of the
statute and other relevant factors, such as applicable international
standards. While the statutory language of CAA section 231 is not
identical to other provisions of Title II of the CAA that direct the
EPA to establish technology-based standards for various types of mobile
sources, the EPA interprets its authority under CAA section 231 to be
similar to those provisions that authorize us to identify a reasonable
balance of specified emissions reduction, cost, safety, noise, and
other factors.\15\ However, we are not compelled under CAA section 231
to obtain the ``greatest degree of emission reduction achievable'' as
per CAA sections 202(a)(3)(A) and 213(a)(3). The EPA does not interpret
the Act as requiring the agency to give subordinate status to other
factors such as cost, safety, and noise in determining what standards
are reasonable for aircraft engines.\16\ Rather, the EPA has great
flexibility under CAA section 231 in determining what standard is most
reasonable for aircraft engines. Moreover, in light of the U.S.
ratification of the Chicago Convention, EPA has historically given
significant weight to uniformity with international requirements as a
factor in setting aircraft engine standards. The fact that most
airplanes already meet the standards does not in itself mean that the
standards are inappropriate, provided the agency has a reasonable basis
after considering all the relevant factors. By the same token, a
technology-forcing standard would not be precluded by CAA section 231,
in light of the forward-looking language of CAA section 231(b).\17\
---------------------------------------------------------------------------
\13\ See 70 FR 69664, 69676 (November 17, 2005); 86 FR 2136,
2157 (January 11, 2021).
\14\ The U.S. Court of Appeals for the D.C. Circuit has held
that CAA section 231 confers an unusually ``broad'' degree of
discretion on EPA to ``weigh various factors'' and adopt aircraft
engine emission standards as the Agency determines are reasonable.
Nat'l Ass'n of Clean Air Agencies v. EPA, 489 F.3d 1221, 1229-30
(D.C. Cir. 2007).
\15\ See, e.g., Husqvarna AB v. EPA, 254 F.3d 195 (D.C. Cir.
2001) (upholding the EPA's promulgation of technology-based
standards for small non-road engines under CAA section 213(a)(3)).
\16\ Cf. Sierra Club v. EPA, 325 F.3d 374, 378-380 (D.C. Cir.
2003) (holding that even a Clean Air Act provision requiring the
``greatest emission reduction achievable'' did not bind the Agency
to weigh ``pure technological capability'' to the exclusion of other
factors like cost, lead time, safety nor ``resolve how [the EPA]
should weigh all these factors'').
\17\ See 38 FR19088 (July 17, 1973); 41 FR 34722 (August 16,
1976); see also NACAA, 489 F.3d at 1229-30.
---------------------------------------------------------------------------
Thus, as in past rulemakings, the EPA notes its authority under the
CAA to issue reasonable aircraft engine standards with either
technology-following or technology-forcing results, provided that, in
either scenario, the Agency has a reasonable basis after considering
all the relevant factors for setting the standard.\18\ Once the EPA
adopts standards, CAA section 232 then directs the Secretary of
Transportation to prescribe regulations to ensure compliance with the
EPA's standards.\19\ Finally, CAA section 233 vests the authority to
promulgate emission standards for aircraft or aircraft engines only in
the Federal Government. States are preempted from adopting or enforcing
any standard respecting aircraft or aircraft engine emissions unless
such standard is identical to the EPA's standards.\20\
---------------------------------------------------------------------------
\18\ See 70 FR 69664, 69676 (November 17, 2005); 86 FR 2136,
2139-2140 (January 11, 2021).
\19\ 42 U.S.C. 7572.
\20\ 42 U.S.C. 7573.
---------------------------------------------------------------------------
B. The Role of the United States in International Aircraft Agreements
The Convention on International Civil Aviation (commonly known as
the Chicago Convention) was signed in 1944 at the Diplomatic Conference
held in Chicago. It was ratified by the United States on August 9,
1946. The Chicago Convention establishes the legal framework for the
development of international civil aviation. The primary objective is
``that international civil aviation may be developed in a safe and
orderly manner and that international air transport services may be
established on the basis of equality of opportunity and operated
soundly and economically.'' \21\ In 1947, ICAO was established, and
later in that same year, ICAO became a specialized agency of the United
Nations (UN). ICAO sets international standards for aviation safety,
security, efficiency, capacity, and environmental protection and serves
as the forum for cooperation in all fields of international civil
aviation. ICAO works with the Chicago Convention's member States and
global aviation organizations to develop international Standards and
Recommended Practices (SARPs), which member States reference when
developing their domestic civil aviation regulations. The United States
is one of 193 currently participating ICAO member
States.<SUP>22 23</SUP> ICAO standards are not self-implementing. They
must first be adopted into domestic law to be legally binding in any
member State.
---------------------------------------------------------------------------
\21\ ICAO, 2006: Convention on International Civil Aviation,
Ninth Edition, Document 7300/9. Available at: <a href="http://www.icao.int/publications/Documents/7300_9ed.pdf">http://www.icao.int/publications/Documents/7300_9ed.pdf</a> (last accessed October 31,
2022).
\22\ Members of ICAO's Assembly are generally termed member
States or contracting States.
\23\ There are currently 193 contracting States (member States)
according to ICAO's website. The list of ICAO member States is
available in the docket for this rulemaking under document
identification number EPA-HQ-OAR-2019-0660-0011.
---------------------------------------------------------------------------
In the interest of global harmonization and international air
commerce, the Chicago Convention urges its member States to
``collaborate in securing the highest practicable degree of uniformity
in regulations, standards, procedures and organization in relation to
aircraft, [. . .] in all matters which such uniformity will facilitate
and improve air navigation.'' \24\ The Chicago Convention also
recognizes that member States may adopt national standards that are
more or less stringent than those agreed upon by ICAO or standards that
are different in character or that comply with the ICAO standards by
other means. Any member State that finds it impracticable to comply in
all respects with any international standard or procedure, or that
determines it is necessary to adopt regulations or practices differing
in any particular respect from those established by an international
standard, is required to give notification to ICAO of the differences
between its own practice and that established by the international
standard.\25\
---------------------------------------------------------------------------
\24\ ICAO, 2006: Convention on International Civil Aviation,
Article 37, Ninth Edition, Document 7300/9.
\25\ Id.
---------------------------------------------------------------------------
ICAO's work on the environment focuses primarily on those problems
that benefit most from a common and coordinated approach on a worldwide
basis, namely aircraft noise and engine emissions. SARPs for the
certification of aircraft noise and aircraft engine emissions are
covered by Annex 16 of the Chicago Convention. To continue to address
aviation environmental issues, in 2004, ICAO established three
environmental goals: (1) limit or reduce the number of people affected
by significant aircraft noise; (2) limit or reduce the impact of
aviation emissions
[[Page 72317]]
on local air quality; and (3) limit or reduce the impact of aviation
greenhouse gas (GHG) emissions on the global climate.
The Chicago Convention has a number of other features that govern
international commerce. First, member States that wish to use aircraft
in international transportation must adopt emission standards that are
at least as stringent as ICAO's standards if they want to ensure
recognition of their airworthiness certificates by other member States.
Member States may ban the use of any aircraft within their airspace
that does not meet ICAO standards.\26\ Second, the Chicago Convention
indicates that member States are required to recognize the
airworthiness certificates issued or rendered valid by the contracting
State in which the aircraft is registered provided the requirements
under which the certificates were issued are equal to or above ICAO's
minimum standards.\27\ Third, to ensure that international commerce is
not unreasonably constrained, a member State that cannot meet or deems
it necessary to adopt regulations differing from the international
standard is obligated to notify ICAO of the differences between its
domestic regulations and ICAO standards.\28\
---------------------------------------------------------------------------
\26\ Id., Article 33.
\27\ Id.
\28\ Id., Article 38.
---------------------------------------------------------------------------
ICAO's Committee on Aviation Environmental Protection (CAEP), which
consists of members and observers from States as well as
intergovernmental and non-governmental organizations representing the
aviation industry and environmental interests, undertakes ICAO's
technical work in the environmental field. The Committee is responsible
for evaluating, researching, and recommending measures to the ICAO
Council that address the environmental impacts of international civil
aviation. CAEP's terms of reference indicate that ``CAEP's assessments
and proposals are pursued taking into account: technical feasibility;
environmental benefit; economic reasonableness; interdependencies of
measures (for example, among others, measures taken to minimize noise
and emissions); developments in other fields; and international and
national programs.'' \29\ The ICAO Council reviews and adopts the
recommendations made by CAEP. It then reports to the ICAO Assembly, the
highest body of the organization, where the main policies on aviation
environmental protection are adopted and translated into Assembly
Resolutions. If ICAO adopts a CAEP proposal for a new environmental
standard, it then becomes part of ICAO standards and recommended
practices (Annex 16 to the Chicago Convention).<SUP>30 31</SUP>
---------------------------------------------------------------------------
\29\ ICAO: CAEP Terms of Reference. A copy of the CAEP Terms of
reference is available in the docket for this rulemaking under
document identification number EPA-HQ-OAR-2019-0660-0006.
\30\ ICAO, 2017: Aircraft Engine Emissions, International
Standards and Recommended Practices, Environmental Protection, Annex
16, Volume II, Fourth Edition, July 2017. The ICAO Annex 16 Volume
II is found on page 17 of the ICAO Products & Services English
Edition of the 2022 catalog, and it is copyright protected; Order
No. AN16-2. The ICAO Annex 16, Volume II, Fourth Edition, includes
Amendment 10 of January 1, 2021. Amendment 10 is also found on page
17 of this ICAO catalog, and it is copyright protected; Order No. AN
16-2/E/12.
\31\ CAEP develops new emission standards based on an assessment
of the technical feasibility, cost, and environmental benefit of
potential requirements.
---------------------------------------------------------------------------
The FAA plays an active role in ICAO/CAEP, including serving as the
representative (member) of the United States at annual ICAO/CAEP
Steering Group meetings, as well as the ICAO/CAEP triennial meetings,
and contributing technical expertise to CAEP's working groups. The EPA
serves as an advisor to the U.S. member at the annual ICAO/CAEP
Steering Group and triennial ICAO/CAEP meetings, while also
contributing technical expertise to CAEP's working groups and assisting
and advising the FAA on aviation emissions, technology, and
environmental policy matters. In turn, the FAA assists and advises the
EPA on aviation environmental issues, technology, and airworthiness
certification matters.
CAEP's predecessor at ICAO, the Committee on Aircraft Engine
Emissions (CAEE), adopted the first international SARPs for aircraft
engine emissions which were proposed in 1981.\32\ These standards
limited aircraft engine emissions of HC, CO, and NO<INF>X</INF>. The
1981 standards applied to newly manufactured engines, which are those
engines manufactured after the effective date of the regulations--also
referred to as in-production engines. In 1993, ICAO adopted a CAEP/2
proposal to tighten the original NO<INF>X</INF> standard by 20 percent
and amend the test procedures.\33\ These 1993 standards applied both to
newly certificated turbofan engines (those engine models that received
their initial type certificate after the effective date of the
regulations, also referred to as new type design engines) and to in-
production engines; the standards had different effective dates for
newly certificated engines and in-production engines. In 1995, CAEP/3
recommended a further tightening of the NO<INF>X</INF> standards by 16
percent and additional test procedure amendments, but in 1997 the ICAO
Council rejected this stringency proposal and approved only the test
procedure amendments. At the CAEP/4 meeting in 1998, the Committee
adopted a similar 16 percent NO<INF>X</INF> reduction proposal, which
ICAO approved in 1998. Unlike the CAEP/2 standards, the CAEP/4
standards applied only to new type design engines after December 31,
2003, and not to in-production engines, leaving the CAEP/2 standards
applicable to in-production engines. In 2004, CAEP/6 recommended a 12
percent NO<INF>X</INF> reduction, which ICAO approved in
2005.<SUP>34 35</SUP> The CAEP/6 standards applied to new engine
designs certificated after December 31, 2007, again leaving the CAEP/2
standards in place for in-production engines before January 1, 2013. In
2010, CAEP/8 recommended a further tightening of the NO<INF>X</INF>
standards by 15 percent for new engine designs certificated after
December 31, 2013.<SUP>36 37</SUP> The Committee also recommended that
the CAEP/6 standards be applied to in-production engines on or after
January 1, 2013, which cut off the production of CAEP/2 and CAEP/4
compliant engines with the exception of spare engines; ICAO adopted
these as standards in 2011.\38\
---------------------------------------------------------------------------
\32\ ICAO, 2017: Aircraft Engine Emissions: Foreword,
International Standards and Recommended Practices, Environmental
Protection, Annex 16, Volume II, Fourth Edition, July 2017. The ICAO
Annex 16, Volume II, Fourth Edition, includes Amendment 10 of
January 1, 2021.
\33\ CAEP conducts its work triennially. Each 3-year work cycle
is numbered sequentially, and that identifier is used to
differentiate the results from one CAEP meeting to another by
convention. The first technical meeting on aircraft emission
standards was CAEP's predecessor, i.e., CAEE. The first meeting of
CAEP, therefore, is referred to as CAEP/2.
\34\ CAEP/5 did not address new aircraft engine emission
standards.
\35\ ICAO, 2017: Aircraft Engine Emissions, International
Standards and Recommended Practices, Environmental Protection, Annex
16, Volume II, Fourth Edition, July 2017. The ICAO Annex 16, Volume
II, Fourth Edition, includes Amendment 10 of January 1, 2021.
\36\ CAEP/7 did not address new aircraft engine emission
standards.
\37\ ICAO, 2010: Committee on Aviation Environmental Protection
(CAEP), Report of the Eighth Meeting, Montreal, February 1-12, 2010,
CAEP/8-WP/80. Available in Docket EPA-HQ-OAR-2010-0687.
\38\ ICAO, 2017: Aircraft Engine Emissions, International
Standards and Recommended Practices, Environmental Protection, Annex
16, Volume II, Fourth Edition, July 2017, Amendment 10. CAEP/8
corresponds to Amendment 7 effective on July 18, 2011. The ICAO
Annex 16, Volume II, Fourth Edition, includes Amendment 10 of
January 1, 2021.
---------------------------------------------------------------------------
At the CAEP/10 meeting in 2016, the Committee agreed to the first
airplane
[[Page 72318]]
carbon dioxide (CO<INF>2</INF>) emission standards, which ICAO approved
in 2017. The CAEP/10 CO<INF>2</INF> standards apply to new type design
airplanes for which the application for a type certificate will be
submitted on or after January 1, 2020, some modified in-production
airplanes on or after January 1, 2023, and all applicable in-production
airplanes manufactured on or after January 1, 2028.
At the CAEP/10 and CAEP/11 meetings in 2016 and 2019, the Committee
agreed to three different forms of international PM standards for
aircraft engines. Maximum PM mass concentration standards were agreed
to at CAEP/10, and PM mass and number standards were agreed to at CAEP/
11. ICAO adopted the PM maximum mass concentration standards in 2017
and the PM mass and number standards in 2020. The CAEP/10 PM standards
apply to in-production engines on or after January 1, 2020, and the
CAEP/11 PM standards apply to new-type and in-production engines on or
after January 1, 2023. In addition to CAEP/10 agreeing to a maximum PM
mass concentration standard, CAEP/10 adopted a reporting requirement
where aircraft engine manufacturers were required to provide PM mass
concentration, PM mass, and PM number emissions data--and other related
parameters--by January 1, 2020 for in-production engines.\39\
---------------------------------------------------------------------------
\39\ More specifically, the international PM maximum mass
concentration standard applies to all turbofan and turbojet engines
of a type or model, and their derivative versions, with a rated
output greater than 26.7 kN and whose date of manufacture of the
individual engine is on or after January 1, 2020 (or those engines
manufactured on or after January 1, 2020).
---------------------------------------------------------------------------
C. The Relationship Between the EPA's Regulation of Aircraft Engine
Emissions and International Standards
Domestically, as required by the CAA, the EPA has been engaged in
reducing harmful air pollution from aircraft engines for over 40 years,
regulating gaseous exhaust emissions, smoke, and fuel venting from
engines.\40\ We have periodically revised these regulations.\41\ The
EPA's actions to regulate certain pollutants emitted from aircraft
engines come directly from the authority in CAA section 231, and we
have aligned the U.S. emission requirements with those adopted by ICAO.
As described in Section II.B, the ICAO/CAEP terms of reference includes
technical feasibility.\42\ Technical feasibility has been interpreted
by CAEP as technology demonstrated to be safe and airworthy and
available for application over a sufficient range of newly certificated
aircraft.\43\ This interpretation resulted in all previous ICAO
emission standards, and the EPA's standards reflecting them, being
anti-backsliding standards (i.e., the standards would not reduce
aircraft PM emissions below current engine emission levels), which are
technology-following.
---------------------------------------------------------------------------
\40\ Emission Standards and Test Procedures for Aircraft; Final
Rule, 38 FR 19088 (July 17, 1973).
\41\ The following are the most recent EPA rulemakings that
revised these regulations. Control of Air Pollution from Aircraft
and Aircraft Engines; Emission Standards and Test Procedures; Final
Rule, 62 FR 25355 (May 8, 1997); Control of Air Pollution from
Aircraft and Aircraft Engines; Emission Standards and Test
Procedures; Final Rule, 70 FR 69664 (November 17, 2005); Control of
Air Pollution from Aircraft and Aircraft Engines; Emission Standards
and Test Procedures; Final Rule, 77 FR 36342 (June 18, 2012);
Control of Air Pollution From Airplanes and Airplane Engines: GHG
Emission Standards and Test Procedures; Final Rule, 86 FR 2136
(January 11, 2021).
\42\ ICAO: CAEP Terms of Reference. Available in the docket for
this rulemaking under document identification number EPA-HQ-OAR-
2019-0660-0006.
\43\ ICAO, 2019: Report of the Eleventh Meeting, Montreal, 4-15
February 2019, Committee on Aviation Environmental Protection,
Document 10126, CAEP/11. It is found on page 27 of the English
Edition of the ICAO Products & Services 2022 Catalog and is
copyright protected: Order No. 10126. The statement on technological
feasibility is located in Appendix C of Agenda Item 3 of this report
(see page 3C-4, paragraph 2.2).
---------------------------------------------------------------------------
For many years the EPA has regulated aircraft engine PM emissions
with smoke number standards.\44\ Since setting the original smoke
number standards in 1973, the EPA has periodically revised these
standards. The EPA amended its smoke standards to align with ICAO's
smoke standards in 1982 \45\ and again in 1984.\46\ Additionally, the
EPA has amended the test procedures for measuring smoke emissions \47\
and modified the effective dates and compliance schedule for smoke
emission standards periodically.\48\ Now, we are adopting three
different forms of aircraft engine PM standards: a PM mass
concentration standard ([mu]g/m\3\), a PM mass standard (mg/kN), and PM
number standard (#/kN). These aircraft engine PM emission standards are
a different way of regulating and/or measuring \49\ aircraft engine PM
emissions in comparison to smoke number emission standards.
---------------------------------------------------------------------------
\44\ See 40 CFR 87.1 (July 1, 2021). ``Smoke means the matter in
exhaust emissions that obscures the transmission of light, as
measured by the test procedures specified in subpart G of this
part.'' ``Smoke number means a dimensionless value quantifying smoke
emission as calculated according to ICAO Annex 16.''
\45\ Control of Air Pollution From Aircraft and Aircraft
Engines; Emission Standards and Test Procedures, Final Rule, 47 FR
58462 (December 30, 1982).
\46\ Control of Air Pollution From Aircraft and Aircraft
Engines; Smoke Emission Standard, Final Rule, 49 FR 31873 (August 9,
1984) (bifurcating EPA's smoke standard for new engines into two
regimes--one for engines with rated output less than 26.7
kilonewtons and one for engines with rated output equal to or
greater than 26.7 kilonewtons).
\47\ 62 FR 25356 (harmonizing EPA procedures with recent
amendments to ICAO test procedures); 70 FR 69664 (same); 77 FR
36342.
\48\ Amendment to Standards, Final Rule, 43 FR 12614 (March 24,
1978) (setting back by two years the effective date for all gaseous
emission standards for newly manufactured aircraft and aircraft gas
turbine engines); Control of Air Pollution from Aircraft and
Aircraft Engines; Extension of Compliance Date for Emission
Standards Applicable to JT3D Engines, Final Rule, 44 FR 64266
(November 6, 1979) (extending the final compliance date for smoke
emission standards applicable to the JT3D aircraft engines by
roughly 3.5 years); Control of Air Pollution from Aircraft;
Amendment to Standards, Final Rule, 45 FR 86946, (December 31, 1980)
(setting back by two years the effective date for all gaseous
emission standards which would otherwise have been effective on
January 1,1981, for aircraft gas turbine engines); Control of Air
Pollution from Aircraft and Aircraft Engines, Final Rule, 46 FR 2044
(January 8, 1981) (extending the applicability of the temporary
exemption provision of the standards for smoke and fuel venting
emissions from some in-use aircraft engines); Control of Air
Pollution From Aircraft and Aircraft Engines; Smoke Emission
Standard, Final Rule, 48 FR 46481 (October 12, 1983) (staying the
smoke regulations for new turbojet and turbofan engines rated below
26.7 kN thrust).
\49\ Also, as described in Section IV.D, the final PM standards
employ a different method for measuring aircraft engine PM emissions
compared to the historical smoke number emission standards.
---------------------------------------------------------------------------
Internationally, the EPA and the FAA have worked within the
standard-setting process of ICAO (CAEP and its predecessor, CAEE) since
the 1970s to help establish international emission standards and
related requirements, which individual member States adopt into
domestic law and regulations. Historically, under this approach,
international emission standards have first been adopted by ICAO, and
subsequently the EPA has initiated rulemakings under CAA section 231 to
establish domestic standards that are harmonized with ICAO's standards.
After the EPA promulgates aircraft engine emission standards, CAA
section 232 requires the FAA to issue regulations to ensure compliance
with the EPA aircraft engine emission standards when certificating
aircraft pursuant to its authority under title 49 of the U.S. Code.
This rulemaking will continue this historical rulemaking approach.
The EPA and FAA worked from 2009 to 2019 within the ICAO/CAEP
standard-setting process on the development of the three different
forms of international aircraft engine PM emission standards (a PM mass
concentration standard, a PM mass standard, and a PM particle number
standard). In this action, we are adopting PM standards equivalent to
ICAO's three different forms of aircraft engine PM emission standards.
Adoption of these standards will meet
[[Page 72319]]
the United States' obligations under the Chicago Convention and will
also help ensure global acceptance of FAA airworthiness certification.
In December 2018, the EPA issued an information collection request
(ICR) that matches the CAEP/10 PM reporting requirements described in
Section II.B.\50\ In addition to the PM standards, this rulemaking
codifies the reporting requirements implemented by this 2018 EPA ICR
into the EPA regulations, as described in Section IV.E. Also, in a
similar time frame as this rulemaking, the EPA will be renewing this
ICR (the ICR needs to be renewed triennially).
---------------------------------------------------------------------------
\50\ Information Collection Request Submitted to OMB for Review
and Approval; Comment Request; Aircraft Engines--Supplemental
Information Related to Exhaust Emissions (Renewal), 83 FR 44621
(August 31, 2018). U.S. EPA, Aircraft Engines--Supplemental
Information Related to Exhaust Emissions (Renewal), OMB Control
Number 2060-0680, ICR Reference Number 201809-2060-08, December 17,
2018.
---------------------------------------------------------------------------
III. Particulate Matter Impacts on Air Quality and Health
A. Background on Particulate Matter
Particulate matter (PM) is a highly complex mixture of solid
particles and liquid droplets distributed among numerous atmospheric
gases which interact with solid and liquid phases. Particles range in
size from those smaller than 1 nanometer (10<SUP>-9</SUP> meter) to
over 100 micrometers ([micro]m, or 10<SUP>-6</SUP> meter) in diameter.
For reference, a typical strand of human hair is 70 [mu]m in diameter
and a grain of salt is about 100 [mu]m. Atmospheric particles can be
grouped into several classes according to their aerodynamic and
physical sizes. Generally, the three broad classes of particles include
ultrafine particles (UFPs, generally considered as particulates with a
diameter less than or equal to 0.1 [mu]m (typically based on physical
size, thermal diffusivity or electrical mobility)), ``fine'' particles
(PM<INF>2.5</INF>; particles with a nominal mean aerodynamic diameter
less than or equal to 2.5 [mu]m), and ``thoracic'' particles
(PM<INF>10</INF>; particles with a nominal mean aerodynamic diameter
less than or equal to 10 [mu]m). Particles that fall within the size
range between PM<INF>2.5</INF> and PM<INF>10</INF>, are referred to as
``thoracic coarse particles'' (PM<INF>10-2.5</INF>, particles with a
nominal mean aerodynamic diameter less than or equal to 10 [mu]m and
greater than 2.5 [mu]m).
Particles span many sizes and shapes and may consist of hundreds of
different chemicals. Particles are emitted directly from sources and
are also formed through atmospheric chemical reactions between PM
precursors; the former are often referred to as ``primary'' particles,
and the latter as ``secondary'' particles. Particle concentration and
composition varies by time of year and location, and, in addition to
differences in source emissions, is affected by several weather-related
factors, such as temperature, clouds, humidity, and wind. Ambient
levels of PM are also impacted by particles' ability to shift between
solid/liquid and gaseous phases, which is influenced by concentration,
meteorology, and especially temperature.
Fine particles are produced primarily by combustion processes and
by transformations of gaseous emissions (e.g., sulfur oxides
(SO<INF>X</INF>), NO<INF>X</INF> and volatile organic compounds (VOCs))
in the atmosphere. The chemical and physical properties of
PM<INF>2.5</INF> may vary greatly with time, region, meteorology, and
source category. Thus, PM<INF>2.5</INF> may include a complex mixture
of different components including sulfates, nitrates, organic
compounds, elemental carbon, and metal compounds. These particles can
remain in the atmosphere for days to weeks and travel through the
atmosphere hundreds to thousands of kilometers.
Particulate matter is comprised of both volatile and non-volatile
PM. PM emitted from the engine is known as non-volatile PM (nvPM), and
PM formed from transformation of an engine's gaseous emissions are
defined as volatile PM.\51\ Because of the difficulty in measuring
volatile PM, which is formed in the engine's exhaust plume and is
significantly influenced by ambient conditions, the EPA is adopting
standards only for the emission of nvPM.
---------------------------------------------------------------------------
\51\ ICAO 2019 Environmental Report. This document is available
in the docket for this rulemaking under document identification
number EPA-HQ-OAR-2019-0660-0022. See pages 98, 100, and 101 for a
description of non-volatile PM and volatile PM.
``During the combustion of hydrocarbon-based fuels, aircraft
engines generate gaseous and particulate matter (PM) emissions. At
the engine exhaust, particulate emissions consist mainly of
ultrafine soot or black carbon emissions. These particles, referred
to as ``non-volatile'' PM (nvPM), are present at high temperatures,
in the engine exhaust. Compared to conventional diesel engines, gas
turbine engines emit non-volatile particles of smaller mean
diameter. Their characteristic size ranges roughly from 15 to 60
nanometers. . . . These particles are invisible to the human eye and
are ultrafine.'' (page 98.)
``Additionally, gaseous emissions from engines can also condense
to produce new particles (i.e., volatile particulate matter--vPM) or
coat the emitted soot particles. Gaseous emissions species react
chemically with ambient chemical constituents in the atmosphere to
produce the so-called secondary particulate matter. Volatile
particulate matter is dependent on these gaseous precursor
emissions. While these precursors are controlled by gaseous
emissions certification and the fuel composition (e.g., sulfur
content) for aircraft gas turbine engines, the volatile particulate
matter is also dependent on the ambient air background
composition.'' (pages 100 and 101.)
---------------------------------------------------------------------------
B. Health Effects of Particulate Matter
Scientific studies show exposure to ambient PM is associated with a
broad range of health effects. These health effects are discussed in
detail in the U.S. EPA's Integrated Science Assessment for Particulate
Matter (PM ISA), which was finalized in December 2019 (2019 PM ISA),
with a more targeted evaluation of studies published since the
literature cutoff date of the 2019 PM ISA in the Supplement to the
Integrated Science Assessment for PM (Supplement).<SUP>52 53</SUP>
Further discussion of PM-related health effects can also be found in
the 2022 Policy Assessment for the review of the PM National Ambient
Air Quality Standards (NAAQS).<SUP>54 55</SUP>
---------------------------------------------------------------------------
\52\ U.S. EPA. Integrated Science Assessment (ISA) for
Particulate Matter (Final Report, 2019). U.S. Environmental
Protection Agency, Washington, DC, EPA/600/R-19/188, 2019.
\53\ U.S. EPA. Supplement to the 2019 Integrated Science
Assessment for Particulate Matter (Final Report, 2022). U.S.
Environmental Protection Agency, Washington, DC, EPA/600/R-22/028,
2022.
\54\ U.S. EPA. Policy Assessment for the Reconsideration of the
National Ambient Air Quality Standards for Particulate Matter (Final
Report, 2022). U.S. Environmental Protection Agency, Washington, DC,
EPA-452/R-22-004, 2022.
\55\ U.S. EPA. Integrated Science Assessment (ISA) for
Particulate Matter (Final Report, 2019). U.S. Environmental
Protection Agency, Washington, DC, EPA/600/R-19/188, 2019.
---------------------------------------------------------------------------
The 2019 PM ISA concludes that human exposures to ambient
PM<INF>2.5</INF> are associated with a number of adverse health effects
and characterizes the weight of evidence for broad health categories
(e.g., cardiovascular effects, respiratory effects, etc.).\56\ The 2019
PM ISA additionally notes that stratified analyses (i.e., analyses that
directly compare PM-related health effects across groups) provide
strong evidence for racial and ethnic differences in PM<INF>2.5</INF>
exposures and in PM<INF>2.5</INF>-related health risk. Recent studies
evaluated in the Supplement support the conclusion of the 2019 PM ISA
with respect to disparities in both PM<INF>2.5</INF> exposure and
health risk by race and ethnicity and provide additional support for
[[Page 72320]]
disparities for lower socioeconomic status populations. As described in
Section III.D, concentrations of PM increase with proximity to an
airport. Further, studies described in Section III.G report that many
communities in close proximity to airports are disproportionately
represented by people of color and low-income populations.
---------------------------------------------------------------------------
\56\ The causal framework draws upon the assessment and
integration of evidence from across epidemiological, controlled
human exposure, and toxicological studies, and the related
uncertainties that ultimately influence our understanding of the
evidence. This framework employs a five-level hierarchy that
classifies the overall weight of evidence and causality using the
following categorizations: causal relationship, likely to be causal
relationship, suggestive of a causal relationship, inadequate to
infer a causal relationship, and not likely to be a causal
relationship (U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F, Table 1-3).
---------------------------------------------------------------------------
The EPA has concluded that recent evidence in combination with
evidence evaluated in the 2009 PM ISA supports a ``causal
relationship'' between both long- and short-term exposures to
PM<INF>2.5</INF> and mortality and cardiovascular effects and a
``likely to be causal relationship'' between long- and short-term
PM<INF>2.5</INF> exposures and respiratory effects.\57\ Additionally,
recent experimental and epidemiologic studies provide evidence
supporting a ``likely to be causal relationship'' between long-term
PM<INF>2.5</INF> exposure and nervous system effects, and long-term
PM<INF>2.5</INF> exposure and cancer. Because of remaining
uncertainties and limitations in the evidence base, the EPA determined
a ``suggestive of, but not sufficient to infer, a causal relationship''
for long-term PM<INF>2.5</INF> exposure and reproductive and
developmental effects (i.e., male/female reproduction and fertility;
pregnancy and birth outcomes), long- and short-term exposures and
metabolic effects, and short-term exposure and nervous system effects.
---------------------------------------------------------------------------
\57\ Short term exposures are usually defined as less than 24
hours duration.
---------------------------------------------------------------------------
More detailed information on the health effects of PM can be found
in a memorandum to the docket.\58\ The EPA is reconsidering a 2020
decision to retain the PM NAAQS.\59\
---------------------------------------------------------------------------
\58\ U.S. EPA, Cook, R. Memorandum to Docket EPA-HQ-OAR-2019-
0660, ``Health and environmental effects of non-GHG pollutants
emitted by turbine engine aircraft--final rule version,'' August 11,
2022.
\59\ Id., p. 6.
---------------------------------------------------------------------------
C. Environmental Effects of Particulate Matter
Environmental effects that can result from particulate matter
emissions include visibility degradation, plant and ecosystem effects,
deposition effects, and materials damage and soiling. These effects are
briefly summarized here and discussed in more detail in the memo to the
docket cited in Section III.B.
PM<INF>2.5</INF> emissions also adversely impact visibility.\60\ In
the Clean Air Act Amendments of 1977, Congress recognized visibility's
value to society by establishing a national goal to protect national
parks and wilderness areas from visibility impairment caused by manmade
pollution.\61\ In 1999, the EPA finalized the regional haze program to
protect the visibility in Mandatory Class I Federal areas.\62\ There
are 156 national parks, forests and wilderness areas categorized as
Mandatory Class I Federal areas.\63\ These areas are defined in CAA
section 162 as those national parks exceeding 6,000 acres, wilderness
areas and memorial parks exceeding 5,000 acres, and all international
parks which were in existence on August 7, 1977. The EPA has also
concluded that PM<INF>2.5</INF> causes adverse effects on visibility in
other areas that are not targeted by the Regional Haze Rule, such as
urban areas, depending on PM<INF>2.5</INF> concentrations and other
factors such as dry chemical composition and relative humidity (i.e.,
an indicator of the water composition of the particles). The secondary
(welfare-based) PM NAAQS provide protection against visibility effects.
In recent PM NAAQS reviews, EPA evaluated a target level of protection
for visibility impairment that is expected to be met through attainment
of the existing secondary PM standards.\64\
---------------------------------------------------------------------------
\60\ U.S. EPA. Integrated Science Assessment (ISA) for
Particulate Matter (Final Report, 2019). U.S. Environmental
Protection Agency, Washington, DC, EPA/600/R-19/188, 2019.
\61\ See CAA section 169(a).
\62\ Regional Haze Regulations; Final Rule, 64 FR 35714 (July 1,
1999).
\63\ National Ambient Air Quality Standards for Particulate
Matter; Final Rule, 62 FR 38652 (July 18, 1997).
\64\ Cook, op. cit., p. 6.
---------------------------------------------------------------------------
1. Deposition of Metallic and Organic Constituents of PM
Several significant ecological effects are associated with
deposition of chemical constituents of ambient PM such as metals and
organics.\65\ Like all internal combustion engines, turbine engines
covered by this rule may emit trace amounts of metals due to fuel
contamination or engine wear. Ecological effects of PM include direct
effects to metabolic processes of plant foliage; contribution to total
metal loading resulting in alteration of soil biogeochemistry and
microbiology, plant and animal growth and reproduction; and
contribution to total organics loading resulting in bioaccumulation and
biomagnification.\66\
---------------------------------------------------------------------------
\65\ U.S. EPA. 2018. Integrated Science Assessment (ISA) for
Oxides of Nitrogen, Oxides of Sulfur and Particulate Matter
Ecological Criteria Second External Review Draft). EPA-600-R-18-097.
Washington, DC. December.
\66\ U.S. EPA. Integrated Science Assessment (ISA) for
Particulate Matter (Final Report, 2019). U.S. Environmental
Protection Agency, Washington, DC, EPA/600/R-19/188, 2019.
---------------------------------------------------------------------------
2. Materials Damage and Soiling
Deposition of PM is associated with both physical damage (materials
damage effects) and impaired aesthetic qualities (soiling effects). Wet
and dry deposition of PM can physically affect materials, adding to the
effects of natural weathering processes, by potentially promoting or
accelerating the corrosion of metals, by degrading paints and by
deteriorating building materials such as stone, concrete and
marble.\67\
---------------------------------------------------------------------------
\67\ U.S. Environmental Protection Agency (U.S. EPA). 2018.
Integrated Science Assessment (ISA) for Oxides of Nitrogen, Oxides
of Sulfur and Particulate Matter Ecological Criteria Second External
Review Draft). EPA-600-R-18-097. Washington, DC. December.
---------------------------------------------------------------------------
D. Near-Source Impacts on Air Quality and Public Health
Airport activity can adversely impact air quality in the vicinity
of airports. Furthermore, these adverse impacts may disproportionately
impact sensitive subpopulations. A recent study by Yim et al (2015)
assessed global, regional, and local health impacts of civil aviation
emissions, using modeling tools that address environmental impacts at
different spatial scales.\68\ The study attributed approximately 16,000
premature deaths per year globally to global aviation emissions, with
87 percent attributable to PM<INF>2.5</INF>. The study concludes that
about a third of these mortalities are attributable to PM<INF>2.5</INF>
exposures within 20 kilometers of an airport. Another study focused on
the continental United States estimated 210 deaths per year
attributable to PM<INF>2.5</INF> from aircraft activity at
airports.\69\ While there are considerable uncertainties associated
with such estimates, these results suggest that in addition to the
contributions of PM<INF>2.5</INF> emissions to regional air quality,
impacts on public health of these emissions in the vicinity of airports
are an important public health concern.
---------------------------------------------------------------------------
\68\ Yim, S.H.L., Lee, G.L., Lee, I.H., Allrogen, F., Ashok, A.,
Caiazzo, F., Eatham, S.D., Malina, R., Barrett, S.R.H. 2015. Global,
regional, and local health impacts of civil aviation emissions.
Environ. Res. Lett. 10: 034001.
\69\ Brunelle-Yeung, E., Masek, T., Rojo, J., Levy, J.,
Arunachalam, S., Miller, S., Barrett, S., Kuhn, S., Waitz, I. 2014.
Assessing the impact of aviation environmental policies on public
health. Transport Policy 34: 21-28.
---------------------------------------------------------------------------
A significant body of research has addressed pollutant levels and
potential health effects in the vicinity of airports. Much of this
research was synthesized in a 2015 report published by the Airport
Cooperative Research Program (ACRP), conducted by the Transportation
Research Board.\70\ The
[[Page 72321]]
report concluded that PM<INF>2.5</INF> concentrations in and around
airports vary considerably, ranging from ``relatively low levels to
those that are close to the NAAQS, and in some cases, exceeding the
standards.'' \71\
---------------------------------------------------------------------------
\70\ Kim, B., Nakada, K., Wayson, R., Christie, S., Paling, C.,
Bennett, M., Raper, D., Raps, V., Levy, J., Roof, C. 2015.
Understanding Airport Air Quality and Public Health Studies Related
to Airports. Airport Cooperative Research Program, ACRP Report 135.
\71\ Id.
---------------------------------------------------------------------------
Furthermore, the report states that ``existing studies indicate
that ultrafine particle concentrations are highly elevated at an
airport (i.e., near a runway) with particle counts that can be orders
of magnitude higher than background with some persistence many meters
downwind (e.g., 600 m).'' \72\ Finally, the report concludes that
PM<INF>2.5</INF> dominates overall health risks posed by airport
emissions.\73\ Moreover, one recently published study concluded that
emissions from aircraft play an etiologic role in pre-term births,
independent of noise and traffic-related air pollution exposures.\74\
---------------------------------------------------------------------------
\72\ Id. at 40.
\73\ Id. at 41.
\74\ Wing, S.E., Larson, T.V., Hudda, N., Boonyarattaphan, S.,
Fruin, S., Ritz, B. 2020. Preterm birth among infants exposed to in
utero ultrafine particles from aircraft emissions. Environ. Health
Perspect. 128(4).
---------------------------------------------------------------------------
Since the publication of the 2015 ACRP literature review, a number
of studies conducted in the United States have been published which
concluded that ultrafine particle number concentrations were elevated
downwind of commercial airports, and that proximity to an airport also
increased particle number concentrations within residences. Hudda et
al. investigated ultrafine particle number concentrations (PNC) inside
and outside 16 residences in the Boston metropolitan area. They found
elevated outdoor PNC within several kilometers of the airport. They
also found that aviation-related PNC infiltrated indoors and resulted
in significantly higher indoor PNC.\75\ In another study in the
vicinity of Logan airport, Hudda et al. analyzed PNC impacts of
aviation activities.\76\ They found that, at sites 4.0 and 7.3 km from
the airport, average PNCs were 2 and 1.33-fold higher, respectively,
when winds were from the direction of the airport compared to other
directions, indicating that aviation impacts on PNC extend many
kilometers downwind of Logan airport. Stacey (2019) conducted a
literature survey and concluded that the literature consistently
reports that particle numbers close to airports are significantly
higher than locations distant and upwind of airports, and that the
particle size distribution is different from traditional road traffic,
with more extremely fine particles.\77\ Similar findings have been
published from European studies.<SUP>78 79 80 81 82 83</SUP> Results of
a monitoring study of communities near Seattle-Tacoma International
Airport also found higher levels of ultrafine PM near the airport, and
an impacted area larger than at near-roadway sites.\84\ The PM
associated with aircraft landing activity was also smaller in size,
with lower black carbon concentrations than near-roadway samples. As
discussed in Section III.B, PM<INF>2.5</INF> exposures are associated
with a number of serious, adverse health effects. Further, the PM
attributable to aircraft emissions has been associated with potential
adverse health impacts.<SUP>85 86</SUP> For example, He et al. (2018)
found that particle composition, size distribution and internalized
amount of particles near airports all contributed to promotion of
reactive organic species in bronchial epithelial cells.
---------------------------------------------------------------------------
\75\ Hudda, N., Simon, N.C., Zamore, W., Durant, J.L. 2018.
Aviation-related impacts on ultrafine number concentrations outside
and inside residences near an airport. Environ. Sci. Technol. 52:
pp. 1765-1772.
\76\ Hudda, N., Simon, M.C., Zamore, W., Brugge, D., Durant,
J.L. 2016. Aviation emissions impact ultrafine particle
concentrations in the greater Boston area. Environ. Sci. Technol.
50: pp. 8514-8521.
\77\ Stacey, B. 2019. Measurement of ultrafine particles at
airports: A review. Atmos. Environ. 198: pp. 463-477.
\78\ Masiol M., Harrison R.M. Quantification of air quality
impacts of London Heathrow Airport (UK) from 2005 to 2012. Atmos
Environ 2017; 116:308-19.
\79\ Keuken, M.P., Moerman, M., Zandveld, P., Henzing, J.S.,
Hoek, G., 2015. Total and size-resolved particle number and black
carbon concentrations in urban areas near Schiphol airport (the
Netherlands). Atmos. Environ. 104: pp. 132-142.
\80\ Pirhadi, M., Mousavi, A., Sowlat, M.H., Janssen, N.A.H.,
Cassee, F.R., Sioutas, C., 2020. Relative contributions of a major
international airport activities and other urban sources to the
particle number concentrations (PNCs) at a nearby monitoring site.
Environ. Pollut, 260: 114027.
\81\ Stacey, B., Harrison, R.M., Pope, F., 2020. Evaluation of
ultrafine particle concentrations and size distributions at London
Heathrow Airport. Atmos. Environ., 222: 117148.
\82\ Ungeheuer, F., Pinxteren, D., Vogel, A. 2021.
Identification and source attribution of organic compounds in
ultrafine particles near Frankfurt International Airport. Atmos.
Chem. Phys. 21: pp. 3763-3775.
\83\ Zhang, X., Karl, M. Zhang, L. Wang, J., 2020. Influence of
Aviation Emission on the Particle Number Concentration near Zurich
Airport. Environ. Sci. Technol. 54: pp. 14161-14171.
\84\ University of Washington. 2019. Mobile Observations of
Ultrafine Particles: The Mov-UP study report.
\85\ Habre. R., Zhou, H., Eckel, S., Enebish, T., Fruin, S.,
Bastain, T., Rappaport, E. Gilliland, F. 2018. Short-term effects of
airport-associated ultrafine particle exposure on lung function and
inflammation in adults with asthma. Environment International 118:
pp. 48-59.
\86\ He, R.-W., Shirmohammadi, F., Gerlofs-Nijland, M.E.,
Sioutas, C., & Cassee, F.R. 2018. Pro-inflammatory responses to PM
(0.25) from airport and urban traffic emissions. The Science of the
total environment, 640-641, pp. 997-100.
---------------------------------------------------------------------------
Because of these potential impacts, a systematic literature review
was recently conducted to identify peer-reviewed literature on air
quality near commercial airports and assess the quality of the
studies.\87\ The systematic review identified seventy studies for
evaluation. These studies consistently showed that particulate matter,
in the form of UFP, is elevated in and around airports. Furthermore,
many studies showed elevated levels of black carbon, criteria
pollutants, and polycyclic aromatic hydrocarbons as well. Finally, the
systematic review, while not focused on health effects, identified a
limited number of references reporting adverse health effects impacts,
including increased rates of premature death, pre-term births,
decreased lung function, oxidative deoxyribonucleic acid (DNA) damage
and childhood leukemia. As indicated in the proposal, more research is
needed linking particle size distributions to specific airport
activities, and proximity to airports, characterizing relationships
between different pollutants, evaluating long-term impacts, and
improving our understanding of health effects.
---------------------------------------------------------------------------
\87\ Riley, K., Cook, R., Carr, E., Manning, B. 2021. A
Systematic Review of The Impact of Commercial Aircraft Activity on
Air Quality Near Airports. City and Environment Interactions,
100066.
---------------------------------------------------------------------------
A systematic review of health effects associated with exposure to
jet engine emissions in the vicinity of airports was also recently
published.\88\ This study concluded that literature on health effects
was sparse, but jet engine emissions have physicochemical properties
similar to diesel exhaust particles, and that exposure to jet engine
emissions is associated with similar adverse health effects as exposure
to diesel exhaust particles and other traffic emissions. A 2010
systematic review by the Health Effects Institute (HEI) concluded that
evidence was sufficient to support a causal relationship between
exposure to traffic-related air pollution and exacerbation of asthma
among children, and suggestive of a causal relationship for childhood
asthma, non-asthma respiratory symptoms, impaired lung function and
cardiovascular mortality.\89\
---------------------------------------------------------------------------
\88\ Bendtsen, K.M., Bengtsen, E., Saber, A., Vogel, U. 2021. A
review of health effects associated with exposure to jet engine
emissions in and around airports. Environ. Health 20:10.
\89\ Health Effects institute. ``Special Report 17: A Special
Report of the Institute's Panel on the Health Effects of Traffic-
Related Air Pollution.'' January 2010.
---------------------------------------------------------------------------
[[Page 72322]]
E. Contribution of Aircraft Emissions to PM in Selected Areas
This section provides background on the contribution of aircraft
engine emissions to local PM concentrations. In some areas with large
commercial airports, turbine engine aircraft can make a significant
contribution to ambient PM<INF>2.5</INF>. To evaluate these potential
impacts, we identified the 25 airports where commercial aircraft
operations are the greatest, based on data for 2017 from the FAA Air
Traffic Data System (ATADS). These 25 commercial airports are located
in 24 counties and 22 metropolitan statistical areas (MSAs). We
compared the contributions of these airports to emissions at both the
county and MSA levels. Comparisons at both scales provide a fuller
picture of how airports are impacting local air quality. Figure III-1
depicts the contribution to county-level PM<INF>2.5</INF> direct
emissions from all turbine aircraft in that county with rated output of
greater than 26.7 kN. Emissions data were obtained from the EPA 2017
National Emissions Inventory (NEI).\90\ Inventory estimates for turbine
engine aircraft were adjusted to account for an improved methodology
for estimating PM from nvPM measurements. This adjustment is described
in detail in Section V.B. The contributions of engines greater than
26.7 kN rated output to total turbine engine emissions at individual
airports were estimated based on FAA data.\91\ At the county level,
contributions to total mobile source PM<INF>2.5</INF> emissions range
from less than 1 to about 16 percent. However, it should be noted that
two airports cross county lines--Hartsfield-Jackson Atlanta
International Airport (Clayton and Fulton counties) and O'Hare (Cook
and DuPage counties). For those airports, percentages are calculated
for the sum of the two counties. In addition, five of these counties
are in nonattainment for either the PM<INF>2.5</INF> or PM<INF>10</INF>
standard. When emissions from these airports are considered as part of
the entire MSA, the contribution is much smaller. Figure III-2 depicts
the contributions at the metropolitan statistical area (MSA) instead of
the county level, and contributions across airports range from about
0.5 to 3 percent. Details of this analysis are described in a
memorandum to the docket.\92\
---------------------------------------------------------------------------
\90\ 2017 National Emissions Inventory: Aviation Component,
Eastern Research Group, Inc., June 25, 2020, EPA Contract No. EP-C-
17-011, Work Order No. 2-19. See section 3.2 for airports and
aircraft related emissions in the Technical Supporting Document for
the 2017 National Emissions Inventory, January 2021 Updated Release.
It should be noted that while identification of the 25 airports with
the greatest commercial activity uses 2017 ATADS data, the 2017 NEI
relies on 2014 ATADS data.
\91\ These data were obtained using radar-informed data from the
FAA Enhanced Traffic Management System (ETMS). The annual fuel burn
and emissions inventories at selected top US airports were based on
the 2015 FAA flight operations database. The fraction of total PM
emissions from aircraft covered by the final PM standards is based
on the ratio of total PM emissions from flights by engines with
thrust rating greater than 26.7 kN compared to PM emissions from the
whole fleet at each airport.
\92\ U.S. EPA, Cook, R. Memorandum to Docket EPA-HQ-OAR-2019-
0660, ``Estimation of 2017 Emissions Contributions of Turbine
Aircraft >26.7 kN to NO<INF>X</INF> and PM<INF>2.5</INF> as a
Percentage of All Mobile PM<INF>2.5</INF> for the Counties and MSAs
in Which the Airport Resides, 25 Largest Carrier Operations--Final
Rule,'' June 14, 2022.
---------------------------------------------------------------------------
BILLING CODE 6560-50-P
[GRAPHIC] [TIFF OMITTED] TR23NO22.165
Figure III-1
[[Page 72323]]
[GRAPHIC] [TIFF OMITTED] TR23NO22.166
BILLING CODE 6560-50-C
Figure III-2
F. Other Pollutants Emitted by Aircraft
In addition to particulate matter, a number of other criteria
pollutants are emitted by the aircraft subject to this final rule.
These pollutants, which are not covered by the rule, include
NO<INF>X</INF>, including nitrogen dioxide (NO<INF>2</INF>), VOC, CO,
and sulfur dioxide (SO<INF>2</INF>). Aircraft also contribute to
ambient levels of hazardous air pollutants (HAP), compounds that are
known or suspected human or animal carcinogens, or that have noncancer
health effects. These compounds include, but are not limited to,
benzene, 1,3-butadiene, formaldehyde, acetaldehyde, acrolein,
polycyclic organic matter (POM), and certain metals. Some POM and HAP
metals are components of PM<INF>2.5</INF> mass measured in turbine
engine aircraft emissions.\93\
---------------------------------------------------------------------------
\93\ Kinsey, J.S., Hays, M.D., Dong, Y., Williams, D.C. Logan,
R. 2011. Chemical characterization of the fine particle emissions
from commercial aircraft engines during the aircraft particle
emissions experiment (APEX) 1-3. Environ. Sci. Technol. 45:3415-
3421.
---------------------------------------------------------------------------
The term polycyclic organic matter (POM) defines a broad class of
compounds that includes the polycyclic aromatic hydrocarbon compounds
(PAHs). POM compounds are formed primarily from combustion and are
present in the atmosphere in gas and particulate form. Metal compounds
emitted from aircraft turbine engine combustion include chromium,
manganese, and nickel. Several POM compounds, as well as hexavalent
chromium, manganese compounds and nickel compounds are included in the
National Air Toxics Assessment, based on potential carcinogenic
risk.\94\ In addition, as mentioned previously, deposition of metallic
compounds can have ecological effects. Impacts of POM and metals are
further discussed in the memorandum to the docket referenced in Section
III.B.
---------------------------------------------------------------------------
\94\ U.S. EPA, Air Toxics Screening Assessment.
---------------------------------------------------------------------------
G. Environmental Justice
The EPA's June 2016 ``Technical Guidance for Assessing
Environmental Justice in Regulatory Analysis'' provides recommendations
on conducting the highest quality analysis feasible, recognizing that
data limitations, time and resource constraints, and analytic
challenges will vary by media and regulatory context.\95\ The EPA
defines environmental justice as the fair treatment and meaningful
involvement of all people regardless of race, color, national origin,
or income with respect to the development, implementation, and
enforcement of environmental laws, regulations, and policies.\96\
---------------------------------------------------------------------------
\95\ ``Technical Guidance for Assessing Environmental Justice in
Regulatory Analysis.'' Environmental Protection Agency (June 2016).
\96\ Fair treatment means that ``no group of people should bear
a disproportionate burden of environmental harms and risks,
including those resulting from the negative environmental
consequences of industrial, governmental and commercial operations
or programs and policies.'' Meaningful involvement occurs when ``(1)
potentially affected populations have an appropriate opportunity to
participate in decisions about a proposed activity [e.g.,
rulemaking] that will affect their environment and/or health; (2)
the public's contribution can influence [the EPA's rulemaking]
decision; (3) the concerns of all participants involved will be
considered in the decision-making process; and (4) [the EPA will]
seek out and facilitate the involvement of those potentially
affected''. A potential EJ concern is defined as ``the actual or
potential lack of fair treatment or meaningful involvement of
minority populations, low-income populations, tribes, and Indigenous
peoples in the development, implementation and enforcement of
environmental laws, regulations and policies.'' See ``Guidance on
Considering Environmental Justice During the Development of an
Action.'' Environmental Protection Agency.
---------------------------------------------------------------------------
When assessing the potential for disproportionately high and
adverse health or environmental impacts of regulatory actions on
minority populations, low-income populations, tribes, and/or Indigenous
peoples, the EPA strives to answer three broad questions: (1) Is there
evidence of potential EJ concerns in the baseline (the state of the
world absent the regulatory action)? Assessing the baseline will allow
the EPA to
[[Page 72324]]
determine whether pre-existing disparities are associated with the
pollutant(s) under consideration (e.g., if the effects of the
pollutant(s) are more concentrated in some population groups). (2) Is
there evidence of potential EJ concerns for the regulatory option(s)
under consideration? Specifically, how are the pollutant(s) and its
effects distributed for the regulatory options under consideration?
And, (3) do the regulatory option(s) under consideration exacerbate or
mitigate EJ concerns relative to the baseline? It is not always
possible to quantitatively assess these questions.
The EPA's 2016 Technical Guidance does not prescribe or recommend a
specific approach or methodology for conducting an environmental
justice analysis, though a key consideration is consistency with the
assumptions underlying other parts of the regulatory analysis when
evaluating the baseline and regulatory options. Where applicable and
practicable, the Agency endeavors to conduct such an analysis. Going
forward, the EPA is committed to conducting environmental justice
analysis for rulemakings based on a framework similar to what is
outlined in the EPA's Technical Guidance, in addition to investigating
ways to further weave environmental justice into the fabric of the
rulemaking process.
Numerous studies have found that environmental hazards such as air
pollution are more prevalent in areas where people of color and low-
income populations represent a higher fraction of the population
compared with the general population, including near transportation
sources.\97\ \98\ \99\ \100\ \101\
---------------------------------------------------------------------------
\97\ Rowangould, G.M. (2013) A census of the near-roadway
population: public health and environmental justice considerations.
Trans Res D 25: pp. 59-67.
\98\ Marshall, J.D., Swor, K.R., Nguyen, N.P. (2014)
Prioritizing environmental justice and equality: diesel emissions in
Southern California. Environ Sci Technol 48: pp. 4063-4068.
\99\ Marshall, J.D. (2000) Environmental inequality: air
pollution exposures in California's South Coast Air Basin. Atmos
Environ 21: pp. 5499-5503.
\100\ Tessum, C.W., Paolella, D.A., Chambliss, SE, Apte, J.S.,
Hill, J.D., Marshall, J.D. (2021) PM<INF>2.5</INF> polluters
disproportionately and systemically affect people of color in the
United States. Science Advances 7:eabf4491.
\101\ Mohai, P., Pellow, D., Roberts Timmons, J. (2009)
Environmental justice. Annual Reviews 34: pp. 405-430.
---------------------------------------------------------------------------
As described in Section III.D, concentrations of PM increase with
proximity to an airport. Air pollution can disproportionately impact
sensitive subpopulations near airports. Henry et al. (2019) studied
impacts of several California airports on surrounding schools and found
that over 65,000 students spend 1 to 6 hours a day during the academic
year being exposed to airport pollution, and the percentage of impacted
students was higher for those who were economically disadvantaged.\102\
Rissman et al. (2013) studied PM<INF>2.5</INF> at the Hartsfield-
Jackson Atlanta International Airport and found that the relationship
between minority population percentages and aircraft-derived PM was
found to grow stronger as concentrations increased.\103\
---------------------------------------------------------------------------
\102\ Henry, R.C., Mohan, S., Yazdani, S. (2019) Estimating
potential air quality impact of airports on children attending the
surrounding schools. Atmospheric Environment, 212: pp. 128-135.
\103\ Rissman, J., Arunachalam, S., BenDor, T., West, J.J.
(2013) Equity and health impacts of aircraft emissions at the
Hartfield-Jackson Atlanta International Airport, Landscape and Urban
Planning 120: pp. 234-247.
---------------------------------------------------------------------------
Additional studies have reported that many communities in close
proximity to airports are disproportionately represented by minorities
and low-income populations. McNair (2020) describes nineteen major
airports that underwent capacity expansion projects between 2000 and
2010, thirteen of which met characteristics of race, ethnicity,
nationality and/or income that indicate a disproportionate impact on
these residents.\104\ Woodburn (2017) reports on changes in communities
near airports from 1970-2010, finding suggestive evidence that at many
hub airports over time, the presence of marginalized groups residing in
close proximity to airports increased.\105\
---------------------------------------------------------------------------
\104\ McNair, A. (2020) Investigation of environmental justice
analysis in airport planning practice from 2000 to 2010. Transp.
Research Part D 81:102286.
\105\ Woodburn, A. (2017) Investigating neighborhood change in
airport-adjacent communities in multiairport regions from 1970 to
2010. Journal of the Transportation Research Board, 2626, pp. 1-8.
---------------------------------------------------------------------------
Although not being conducted as part of this rulemaking, the EPA is
conducting a demographic analysis to explore whether populations living
nearest the busiest runways show patterns of racial and socioeconomic
disparity.\106\ This will help characterize the state of environmental
justice concerns and inform potential future actions. Finely resolved
population data (i.e., 30 square meters) will be paired with census
block group demographic characteristics to evaluate if people of color,
children, Indigenous populations, and low-income populations are
disproportionately living near airport runways compared to populations
living further away. The results of this analysis could help inform
additional policies to reduce pollution in communities living in close
proximity to airports.
---------------------------------------------------------------------------
\106\ EPA anticipates that the results of the study will be
released publicly in a separate document from the final rule.
---------------------------------------------------------------------------
The final in-production standards for both PM mass and PM number
are levels that all aircraft engines in production currently meet to
align with ICAO's standards. Thus, the final standards are not expected
to result in emission reductions, beyond the business-as-usual fleet
turnover that would occur absent the final standards. Therefore, we do
not anticipate an improvement in air quality for those who live near
airports where these aircraft operate, beyond what may occur as a
result of fleet turnover and from any reductions in emissions from
other sectors contributing to air quality near airports.
Response to comments on Section III of this action can be found in
the Response to Comments document. In addition, all website addresses
for references cited in this section are provided in a memorandum to
the docket.\107\
---------------------------------------------------------------------------
\107\ U.S. EPA, Cook, R. Memorandum to Docket EPA-HQ-OAR-2019-
0660, ``Web addresses for references cited in Section III of the
preamble for Control of Air Pollution from Aircraft Engines:
Emission Standards and Test Procedures; Final Rule,'' November 9,
2022.
---------------------------------------------------------------------------
IV. Details of the Final Rule
In determining what final PM standards are appropriate under CAA
section 231 and after consultation with FAA, the EPA considered the
level of standards that could be met with the application of requisite
technology within the necessary period of time that would allow the
United States to meet its obligations under the Chicago Convention to
at least match the ICAO standards, and gave appropriate consideration
to the cost of compliance within this period. This determination also
took into account the requirement that EPA's revised standards not
significantly increase noise and adversely affect safety. The EPA
considered the statutory requirements in CAA section 231 and other
relevant factors as described in Section VI of both the proposed rule
and this final rule, and we concluded that it was reasonable and
appropriate to finalize the new PM standards that match the
international standards in scope, stringency, and effective date. The
EPA has consulted with FAA and believes sufficient lead time has been
provided since the technology has already been developed and
implemented by manufacturers to comply with the new PM standards. Also,
as described in Section IV.F.1, the EPA is confident that the final
standards will not significantly increase noise and adversely affect
[[Page 72325]]
safety. Further, as described in Section VI.D, the EPA does not project
any costs associated with these standards because all in-production
engines meet the in-production standards, nearly all in-production
engines meet the new type design standard, and future new type designs
are expected to meet the new type design standard. In addition to the
statutory requirements of CAA section 231, the EPA, after consultation
with FAA, also took into consideration the importance of controlling PM
emissions, international harmonization of aviation requirements, and
the international nature of the aircraft industry. The EPA gave
significant weight to the United States' treaty obligations under the
Chicago Convention in determining the need for and appropriate levels
of PM standards. U.S. manufacturers could be at a significant
disadvantage if the United States fails to adopt standards by the
international implementation date. Also, given the short timeframe from
this final action and the international implementation date, there
would not be enough lead time for manufacturers to respond to more
stringent standards that would require them to develop and implement
new technologies.
These considerations led the EPA to determine that adopting
aircraft engine PM standards based on engine standards adopted by ICAO
is appropriate at this time. When developing the PM standards, ICAO
adopted three different methods of measuring the amount of PM emitted.
The first is PM mass, or a measure of the total weight of the particles
produced over the test cycle. This is how the EPA has historically set
PM emission standards for other sectors. The second is PM number, or
the number of particles produced by the engine over the test cycle.
These are two different methods of measuring the same pollutant, PM,
but each provides distinct and valuable information. Third, ICAO
developed PM mass concentration standards, as a replacement to the
existing standards based on smoke number.
The EPA's final action will apply to subsonic turbofan and turbojet
engines of a type or model with a rated output (maximum thrust
available for takeoff) greater than 26.7 kN, hereinafter referred to as
covered engines, and consists of three key parts: (1) PM mass and
number emission standards for covered engines, (2) a change in test
procedure and form of the existing standards for covered engines--from
smoke number to PM mass concentration, and (3) new testing and
measurement procedures for the PM emission standards and various
updates to the existing gaseous exhaust emissions test procedures.
Sections IV.A through IV.C describe the final mass, number, and
mass concentration standards for aircraft engines. Section IV.D
describes the test procedures and measurement procedures associated
with the PM standards. Section IV.E presents information related to the
reporting requirements.
As discussed in Section III.A, PM<INF>2.5</INF> consists of both
volatile and non-volatile PM (nvPM), although only non-volatile PM will
be covered by the adopted standards. Only non-volatile PM is present at
the engine exit because the exhaust temperature is too high for
volatile PM to form. The volatile PM (or secondary PM) is formed as the
engine exhaust plume cools and mixes with the ambient air. The result
of this is that the volatile PM is significantly influenced by the
ambient conditions (or ambient air background composition). Because of
this complexity, a test procedure to measure volatile PM has not yet
been developed for aircraft engines. To directly measure non-volatile
PM, ICAO agreed to adopt a measurement procedure, as described in
Section IV.D, which is based on conditions that prevent the formation
of volatile PM upstream of the measurement instruments. The intent of
this approach is to improve the consistency and repeatability of the
non-volatile PM measurement procedure.
Due to the international nature of the aviation industry, there is
an advantage to working within ICAO to secure the highest practicable
degree of uniformity in international aviation regulations and
standards. Uniformity in international aviation regulations and
standards is a goal of the Chicago Convention, because it ensures that
passengers and the public can expect similar levels of protection for
safety and human health and the environment regardless of manufacturer,
airline, or point of origin of a flight. Further, it helps prevent
barriers in the global aviation market, benefiting both U.S. aircraft
engine manufacturers and consumers.
When developing new emission standards, ICAO/CAEP seeks to capture
the technological advances made in the control of emissions through the
adoption of anti-backsliding standards reflecting the current state of
technology. The PM standards the EPA is adopting were developed using
this approach. Thus, the adoption of these aircraft engine standards
into U.S. law will simultaneously prevent aircraft engine PM levels
from increasing beyond their current levels, align U.S. domestic
standards with the ICAO standards for international harmonization, meet
the United States' treaty obligations under the Chicago Convention.
These standards will also allow U.S. manufacturers of covered
aircraft engines to remain competitive in the global marketplace. The
ICAO aircraft engine PM emission standards have been, or are being,
adopted by other ICAO member states that certify aircraft engines. In
the absence of U.S. standards implementing the ICAO aircraft engine PM
emission standards, the United States would not be able to certify
aircraft engines to the PM standards. In this case, U.S. civil aircraft
engine manufacturers could be forced to seek PM emissions certification
from an aviation certification authority of another country to market
and operate their aircraft engines internationally. Foreign
certification authorities may not have the resources to certify
aircraft engines from U.S. manufacturers in a timely manner, which
could lead to delays in these engines being certified. Thus, U.S.
manufacturers could be at a disadvantage if the United States does not
adopt standards that are at least as stringent as the ICAO standards
for PM emissions. This action to adopt, in the United States, PM
standards that match the ICAO standards will help ensure international
consistency and acceptance of U.S.-manufactured engines worldwide.
The EPA considered whether to propose standards more stringent than
the ICAO standards. See 87 FR 6324, 6337 (February 3, 2022). As noted
in the preceding paragraphs, the EPA, after consultation with FAA,
considered the statutory requirements under CAA section 231, the
importance of controlling PM emissions, international harmonization of
aviation requirements, the international nature of the aircraft
industry and air travel, and the United States' obligations under the
Chicago Convention in evaluating which stringency of standards to
propose. These considerations have historically led the EPA to adopt
international standards developed through ICAO. The EPA concluded that
proposing and now adopting standards equivalent to the ICAO PM
standards in place of more stringent standards is appropriate in part
because international uniformity and regulatory certainty are important
elements of these standards. This is especially true for these final
standards because they change our approach to regulating aircraft PM
emissions from past smoke measurements to the measurement of nvPM mass
concentration, nvPM mass, and nvPM number for the first time. It is
[[Page 72326]]
appropriate to gain experience from the implementation of these nvPM
standards before considering whether to adopt more stringent nvPM mass
and/or nvPM number standards, or whether another approach to PM
regulation would better address the health risks of PM emissions from
aircraft engines. Additionally, the U.S. Government, through the FAA,
State Department, and the EPA, played a significant role in the
development of these standards through a multi-year process. The EPA
believes that international cooperation on aircraft emissions brings
substantial benefits overall to the United States. Given that the EPA
and FAA invested significant effort and considerable resources to
develop these standards and obtain international consensus for ICAO to
adopt these standards, a decision by the United States to deviate from
them might well undermine future efforts by the United States to seek
international consensus on aircraft emission standards. For these
reasons, the EPA placed significant weight on international regulatory
uniformity and certainty and is finalizing standards that match the
standards which the EPA worked to develop and adopt at ICAO.
A. PM Mass Standards for Aircraft Engines
1. Applicability of Standards
These standards for PM mass, like the ICAO standards, will apply to
covered engines whose date of manufacture is on or after January 1,
2023.\108\ These standards will not apply to engines manufactured prior
to this applicability date.
---------------------------------------------------------------------------
\108\ ICAO, 2017: Aircraft Engine Emissions, International
Standards and Recommended Practices, Environmental Protection, Annex
16, Volume II, Fourth Edition, July 2017, III-4-3 & III-4-4pp. The
ICAO Annex 16, Volume II, Fourth Edition, includes Amendment 10 of
January 1, 2021.
\109\ In most cases, the engine manufacturer applies to the FAA
for the type certification; however, in some cases the applicant may
be different than the manufacturer (e.g., designer).
---------------------------------------------------------------------------
The level of the standard will vary based on when the initial type
certification application is submitted.\109\ Covered engines for which
the type certificate application was first submitted on or after
January 1, 2023 will be subject to the new type level in Section
IV.A.2. These engines are new engines that have not been previously
certificated.
Covered engines manufactured on or after January 1, 2023 will be
subject to the in-production level, in Section IV.A.3.
2. New Type nvPM Mass Numerical Emission Limits for Aircraft Engines
Covered engines whose initial type certification application is
submitted to the FAA on or after January 1, 2023 shall not exceed the
level, as defined by Equation IV-1. As described in Section IV.D, the
nvPM mass limit is based on milligram (mg) of PM, as determined over
the LTO cycle, divided by kN of rated output (rO).
[GRAPHIC] [TIFF OMITTED] TR23NO22.167
3. In Production nvPM Mass Numerical Emission Limits for Aircraft
Engines
Covered engines that are manufactured on or after January 1, 2023
shall not exceed the level, as defined by Equation IV-2.
[GRAPHIC] [TIFF OMITTED] TR23NO22.168
4. Graphical Representation of nvPM Mass Numerical Emission Limits
Figure IV-1 shows how the nvPM mass emission limits compare to
known in-production engines. Data shown in this figure is from the ICAO
Engine Emissions Databank (EEDB) \110\.
---------------------------------------------------------------------------
\110\ ICAO Aircraft Engine Emissions Databank, July 20, 2021,
``edb-emissions-databank v28C (web).xlsx'', European Union Aviation
Safety Agency (EASA), <a href="https://www.easa.europa.eu/domains/environment/icao-aircraft-engine-emissions-databank">https://www.easa.europa.eu/domains/environment/icao-aircraft-engine-emissions-databank</a>.
---------------------------------------------------------------------------
BILLING CODE 6560-50-P
[[Page 72327]]
[GRAPHIC] [TIFF OMITTED] TR23NO22.169
Figure IV-1--nvPM mass standards compared to in-production engine LTO
emission rates
B. PM Number Standards for Aircraft Engines
1. Applicability of Standards
These standards for PM number, like the ICAO standards, will apply
to covered engines whose date of manufacture is on or after January 1,
2023.\111\ These standards will not apply to engines manufactured prior
to this applicability date.
---------------------------------------------------------------------------
\111\ ICAO, 2017: Aircraft Engine Emissions, International
Standards and Recommended Practices, Environmental Protection, Annex
16, Volume II, Fourth Edition, July 2017, III-4-4pp. The ICAO Annex
16, Volume II, Fourth Edition, includes Amendment 10 of January 1,
2021.
---------------------------------------------------------------------------
The level of the standard will vary based on when the initial type
certification application is submitted. Covered engines for which the
type certificate application was first submitted on or after January 1,
2023 will be subject to the new type level in Section IV.B.2. These are
new engines that have not been previously certificated.
Covered engines manufactured on or after January 1, 2023 will be
subject to the in-production level, in Section IV.B.3.
2. New Type nvPM Number Numerical Emission Limits for Aircraft Engines
Covered engines whose initial type certification application is
submitted to the FAA on or after January 1, 2023 shall not exceed the
level, as defined by Equation IV-3. As described in Section IV.D, the
nvPM number limit is based on number of particles, as determined over
the LTO cycle, divided by kN of rO.
[GRAPHIC] [TIFF OMITTED] TR23NO22.170
3. In Production nvPM Number Numerical Emission Limits for Aircraft
Engines
Covered engines that are manufactured on or after January 1, 2023
shall not exceed the level, as defined by Equation IV-4.
[[Page 72328]]
[GRAPHIC] [TIFF OMITTED] TR23NO22.171
4. Graphical Representation of nvPM Number Numerical Emission Limits
Figure IV-2 shows how the nvPM number emission limits compare to
known in-production engines. Data shown in this figure is from the ICAO
Engine Emissions Databank (EEDB).\112\
---------------------------------------------------------------------------
\112\ ICAO Aircraft Engine Emissions Databank, July 20, 2021,
``edb-emissions-databank v28C (web).xlsx,'' European Union Aviation
Safety Agency (EASA).
[GRAPHIC] [TIFF OMITTED] TR23NO22.172
---------------------------------------------------------------------------
BILLING CODE 6560-50-C
Figure IV-2--nvPM number standards compared to in-production engine LTO
emission rates
C. PM Mass Concentration Standard for Aircraft Engines
The previous smoke number-based standards were adopted to reduce
the visible smoke emitted by aircraft engines. Smoke number is
quantified by measuring the opacity of a filter after soot has been
collected upon it during the test procedure. Another means of
quantifying the smoke from an engine exhaust is through PM mass
concentration (PM<INF>mc</INF>).
ICAO developed a PM mass concentration standard during the CAEP/10
cycle and adopted it in 2017.\113\ This PM mass concentration standard
was developed to provide equivalent exhaust visibility control as the
existing smoke number standard starting on January 1, 2020. With the
EPA's involvement, the ICAO PM mass concentration limit line was
developed using measured smoke number and PM mass concentration data
from several engines to derive a smoke number-to-PM mass concentration
correlation. This correlation was then used to transform the existing
smoke number-based limit line into a generally equivalent PM mass
concentration limit line, which was ultimately adopted by ICAO as the
CAEP/10 p.m. mass concentration standard. The intention when the
equivalent PM mass concentration standard was adopted was that
equivalent visibility control would be maintained and testing would
coincide with the PM mass and PM number measurement, thus removing the
need to separately test and measure smoke number. In addition to CAEP/
10 agreeing to a maximum PM mass concentration standard, CAEP/10
adopted a reporting requirement where aircraft engine manufacturers
were required to provide PM mass concentration, PM mass, and PM number
emissions data--and other related parameters--by January 1, 2020 for
in-production engines.
---------------------------------------------------------------------------
\113\ ICAO, 2016: Tenth Meeting Committee on Aviation
Environmental Protection Report, Doc 10069, CAEP/10.
---------------------------------------------------------------------------
While the ICAO PM mass concentration standard was intended to have
equivalent visibility control as the existing smoke number standard,
the method used to derive it was based on limited data and needed to be
confirmed for regulatory purposes. Additional analysis was conducted
during the CAEP/11 cycle to confirm this equivalence. The EPA followed
this work as it progressed, provided input
[[Page 72329]]
during the process, and ultimately concurred with the results.\114\ The
analysis, based on aerosol optical theory and visibility criterion,
demonstrated with a high level of confidence that the ICAO PM mass
concentration standard did indeed provide equivalent visibility control
as the existing smoke number standard. This provided the justification
for ICAO to agree to end applicability of the existing smoke number
standard for engines subject to the PM mass concentration standard,
effective January 1, 2023.
---------------------------------------------------------------------------
\114\ ICAO, 2019: Report of Eleventh Meeting, Montreal, 4-15
February 2019, Committee on Aviation Environmental Protection,
Document 10126, CAEP/11. The analysis performed to confirm the
equivalence of the PM mass concentration standard and the SN
standard is located in Appendix C (starting on page 3C-33) of this
report.
---------------------------------------------------------------------------
1. PM Mass Concentration Standard
The EPA is adopting a PM mass concentration standard for all
covered engines manufactured on or after January 1, 2023.\115\ This
standard has the same form, test procedures, and stringency as the
CAEP/10 p.m. mass concentration standard adopted by ICAO in 2017. Note,
the applicability date of the mass concentration standard, finalized in
this action, represents a delay from the January 1, 2020 date agreed to
by ICAO \116\. The PM mass concentration standard is based on the
maximum concentration of PM emitted by the engine at any thrust
setting, measured in micrograms ([micro]g) per meter cubed (m\3\). This
is similar to the previous smoke standard, which is also based on the
measured maximum at any thrust setting. Section IV.D describes the
measurement procedure. Like the LTO-based PM mass and PM number
standards discussed in Section IV.A and Section IV.B (and described in
the introductory paragraphs of Section IV), this is based on the
measurement of nvPM only, not total PM emissions.
---------------------------------------------------------------------------
\115\ ICAO, 2017: Aircraft Engine Emissions, International
Standards and Recommended Practices, Environmental Protection, Annex
16, Volume II, Fourth Edition, July 2017, III-4-3. The ICAO Annex
16, Volume II, Fourth Edition, includes Amendment 10 of January 1,
2021.
\116\ A second component of the CAEP/10 agreement was data
collection by January 1, 2020, so the EPA implemented domestically
by updating the Aircraft Engine Emission ICR (EPA ICR Number
2427.04, OMB Control Number 2060-0680) on December 31, 2018 to
include PM emission data.
---------------------------------------------------------------------------
To determine compliance with the PM mass concentration standard,
the maximum nvPM mass concentration [[mu]g/m\3\] will be obtained from
measurements at sufficient thrust settings such that the emission
maximum can be determined. The maximum value will then be converted to
a characteristic level in accordance with the procedures in ICAO Annex
16, Volume II, Appendix 6. The resultant characteristic level must not
exceed the regulatory level determined from the following formula:
[GRAPHIC] [TIFF OMITTED] TR23NO22.178
Engines certificated under the new PM mass concentration standard
will not need to certify smoke number values and will not be subject to
in-use smoke standards. It is important to note that other smoke number
standards remain in effect for turbofan and turbojet aircraft engines
at or below 26.7 kN rated output and for turboprop engines. Also, the
in-use smoke standards will continue to apply to some already
manufactured aircraft engines that were certified to smoke number
standards. In this final rule, the EPA did not reexamine or reopen the
existing smoke number standards. Any comments we received on the
existing smoke number standards are beyond the scope of this
rulemaking.\117\
---------------------------------------------------------------------------
\117\ The EPA proposed to extend the applicability of the smoke
standards to engines of less than or equal to 26.7 kilonewtons (kN)
rated output used in supersonic airplanes, and so the single comment
received on the extended applicability is within the scope of this
rulemaking and is responded to in the Response to Comments document.
---------------------------------------------------------------------------
2. Graphical Representation of nvPM Mass Concentration Numerical
Emission Limit
Figure IV-3 shows how the nvPM mass concentration emission limits
compare to known in-production engines, which all were certified to the
previous smoke standard. Data shown in this figure is from the ICAO
Engine Emissions Databank (EEDB).\118\
---------------------------------------------------------------------------
\118\ ICAO Aircraft Engine Emissions Databank, July 20, 2021,
``edb-emissions-databank v28C (web).xlsx,'' European Union Aviation
Safety Agency (EASA).
---------------------------------------------------------------------------
[[Page 72330]]
[GRAPHIC] [TIFF OMITTED] TR23NO22.173
BILLING CODE 6560-50-C
Figure IV-3--nvPM Mass Concentration Standard
D. Test and Measurement Procedures
1. Aircraft Engine PM Emissions Metrics
When developing the PM standards, ICAO adopted three different
methods of measuring the amount of PM emitted. The first is PM mass, or
a measure of the total weight of the particles produced over the test
cycle. This is how the EPA has historically measured PM emissions
subject to standards for other sectors. The second is PM number, or the
number of particles produced by the engine over the test cycle. These
are two different methods of measuring the same pollutant, PM, but each
provides valuable information. Third, ICAO developed PM mass
concentration standards, as an alternative to the existing visibility
standards based on smoke.
The EPA is incorporating by reference the metrics agreed at ICAO
and incorporated into Annex 16 Volume II, to measure PM mass (Equation
IV-6) and PM number (Equation IV-7). These metrics are based on a
measurement of the nvPM emissions, as measured at the instrument, over
the LTO cycle and is normalized by the rated output of the engine (rO).
[GRAPHIC] [TIFF OMITTED] TR23NO22.174
The EPA is adopting the PM mass concentration standard based on the
maximum mass concentration, in micrograms per meter cubed, produced by
the engine at any thrust setting.
Regulatory compliance with the emission standards is based on the
product of Equation IV-6 or Equation IV-7 or mass concentration divided
by the appropriate factor from Table IV-2, to obtain the characteristic
level that is used to determine compliance with emission standards (see
Section IV.D.4).
2. Test Procedure
The EPA is incorporating by reference the PM test and measurement
procedures in ICAO Annex 16, Volume II. These procedures were developed
in conjunction with the Society of Automotive Engineers (SAE) E-31
Aircraft Exhaust Emissions
[[Page 72331]]
Measurement Committee \119\ in close consultation between government
and industry, and subsequently they were adopted by ICAO and
incorporated into ICAO Annex 16, Volume II.
---------------------------------------------------------------------------
\119\ The E-31 Committee develops and maintains standards for
measurement of emissions from aircraft engines. (See <a href="https://www.sae.org/works/committeeHome.do?comtID=TEAE31">https://www.sae.org/works/committeeHome.do?comtID=TEAE31</a>, last accessed
October 31, 2022).
---------------------------------------------------------------------------
These procedures build off the existing ICAO Annex 16, Volume II
aircraft engine measurement procedures for gaseous pollutants. As
described in the Annex 16, at least three engine tests need to be
conducted to determine the emissions rates. These tests can be
conducted on a single engine or multiple engines.\120\ A representative
sample of the engine exhaust is sampled at the engine exhaust exit. The
exhaust then travels through a heated sample line where it is diluted
and kept at a constant temperature prior to reaching the measurement
instruments.
---------------------------------------------------------------------------
\120\ For example, all three tests could be conducted on a
single engine. Or two tests could be conducted on one engine and one
test on a second engine. Or three separate engines could each be
tested a single time.
---------------------------------------------------------------------------
The methodology for measuring PM from aircraft engines differs from
certain other EPA test procedures for mobile source PM<INF>2.5</INF>
standards in two ways. First, as discussed in the introductory
paragraphs of Section IV, the procedure is designed to measure only the
non-volatile component of PM. The measurement of volatile PM is very
dependent on the environment where it is measured. The practical
development of a standardized method of measuring volatile PM from
aircraft engines has proved challenging. Therefore, the development of
a procedure for measuring nvPM was prioritized by ICAO and SAE E-31and
the result is adopted in this final rule.
Second, the sample is measured continuously rather than being
collected on a filter and measured after the test. This approach was
taken primarily for the practical reasons that, due to high dilution
rates leading to relatively low concentrations of PM in the sample,
collecting enough particulate on a filter to analyze has the potential
to take hours. Given the high fuel flow rates of these engines, such
lengthy test modes would be very expensive. Additionally, because of
the high volume of air required to run a jet engine and the extreme
engine exhaust temperatures, it is not possible to collect the full
exhaust stream in a controlled manner as is done for other mobile
source PM<INF>2.5</INF> measurements.
Included in the procedures now incorporated by reference by the EPA
are measurement system specifications and requirements, instrument
specifications and calibration requirements, fuel specifications, and
corrections for fuel composition, dilution, and thermophoretic losses
in the collection part of the sampling system.
To create a uniform sampling system design that works across gas
turbine engine testing facilities, the test procedure calls for a 35-
meter sample line. This results in a significant portion of the PM
being lost in the sample lines, on the order of 50 percent for PM mass
and 90 percent for PM number. These particle losses in the sampling
system are not corrected for in the standards. Compliance with the
standard is based on the measurement at the instruments rather than the
exit plane of the engine (instruments are 35 meters from engine exit).
This is due to the lack of robustness of the sampling system particle
loss correction methodology and that a more stringent standard at the
instrument will lead to a reduction in the nvPM emissions at the engine
exit plane. A correction methodology has been developed to better
estimate the actual PM emitted into the atmosphere. This correction is
described in Section V.A.2.
3. Test Duty Cycles
Mass and number PM emissions are measured over the LTO cycle shown
in Table IV-1. This is the same duty cycle used to measure gaseous
emissions from aircraft engines and is intended to represent operations
and flight under an altitude of 3,000 feet near an airport. Emissions
rates for each mode can be calculated by testing the engine(s) over a
sufficient range of thrust settings such that the emission rates at
each condition in Table IV-1 can be determined.
Table IV-1--Landing and Take-Off Cycle Thrust Settings and Time in Mode
\121\
------------------------------------------------------------------------
Time in
LTO operating mode Thrust setting operating mode
percent rO minutes
------------------------------------------------------------------------
Take-off................................ 100 0.7
Climb................................... 85 2.2
Approach................................ 30 4.0
Taxi/ground idle........................ 7 26.0
------------------------------------------------------------------------
The previous smoke number standard was adopted to reduce the
visible smoke emitted from aircraft engines. Smoke number has been
determined by measuring the visibility or opacity of a filter after
soot has been collected upon it during the test procedure. Another
means of measuring this visibility is by direct measurement of the
particulate matter mass concentration. By measuring visibility based on
mass concentration rather than smoke number, the number of tests needed
can be reduced, and mass concentration data can be collected
concurrently with other PM measurements. Like the previous smoke
standard, the PM mass concentration standard is be based on the maximum
value at any thrust setting. The engine(s) will be tested over a
sufficient range of thrust settings that the maximum can be determined.
This maximum could be at any thrust setting and is not limited to the
LTO thrust points in Table IV-1.
---------------------------------------------------------------------------
\121\ ICAO, 2017: Aircraft Engine Emissions, International
Standards and Recommended Practices, Environmental Protection, Annex
16, Volume II, Fourth Edition, July 2017, III-4-2. The ICAO Annex
16, Volume II, Fourth Edition, includes Amendment 10 of January 1,
2021.
---------------------------------------------------------------------------
The EPA is incorporating by reference ICAO's Annex 16 to the
Convention on International Civil Aviation, Environmental Protection,
Volume II--Aircraft Engine Emissions, Fourth Edition, July 2017.
4. Characteristic Level
EPA is incorporating by reference Appendix 6 to ICAO Annex 16,
Volume II--International Standards and Recommended Practices for
correcting engine measurements to characteristic value. Like existing
gaseous standards, compliance with the PM standards adopted in this
action is based on the characteristic level of the engine. The
characteristic level is a statistical
[[Page 72332]]
method of accounting for engine-to-engine variation in the measurement
based on the number of engines tested. A minimum of three engine
emissions tests is needed to determine the engine type's emissions
rates for compliance with emission standards. The more engines that are
used for testing increases the confidence that the emissions rate
measured is from a typical engine rather than a high or low engine.
Table IV-2 is reproduced from Annex 16 Volume II Appendix 6 Table
A6-1 and shows how these factors change based on the number of engines
tested.\122\ As the number of engines tested increases, the factor also
increases resulting in a smaller adjustment and reflecting the
increased confidence that the emissions rate is reflective of the
average engine off the production line. In this way, there is an
incentive to test more engines to reduce the characteristic adjustment
while also increasing confidence that the measured emissions rate is
representative of the typical production engine.
---------------------------------------------------------------------------
\122\ ICAO, 2017: Aircraft Engine Emissions, International
Standards and Recommended Practices, Environmental Protection, Annex
16, Volume II, Fourth Edition, July 2017, App 6-2pp. The ICAO Annex
16, Volume II, Fourth Edition, includes Amendment 10 of January 1,
2021.
[GRAPHIC] [TIFF OMITTED] TR23NO22.177
For PM mass and PM number, the characteristic level is based on the
mean of all engines tested, and appropriately corrected, divided by the
factor corresponding to the number of engine tests performed in Table
IV-1. For PM mass concentration, the characteristic level is based on
the mean of the maximum values of all engines tested, and appropriately
corrected, divided by the factor corresponding to the number of engine
tests performed in Table IV-2.
For example, an engine type where three measurements were obtained
from the same engine has an nvPM mass metric value of 100 mg/kN (mean
metric value of all engine tests). The nvPM LTO mass factor (or nvPM
mass characteristic factor) from Table IV-2 for three engines is
0.7194. The metric value, with applicable corrections applied, is then
divided by the factor to obtain the characteristic level of the engine.
Therefore, the resulting characteristic level for this engine type, to
determine compliance with the nvPM mass standard is 139.005 mg/kN. If
instead three engines are each tested once, the characteristic factor
would be 0.8858 and the nvPM mass characteristic level to determine
compliance with the standard would be 112.892 mg/kN.
An engine type's characteristic level can also be further improved
by testing additional engines. For example, if 10 separate engines were
tested of the same type, the nvPM mass characteristic factor becomes
0.9375. The resulting characteristic level (assuming the average nvPM
mass metric value remains 100 mg/kN) would be 106.667 mg/kN. This
approach could be used if an engine exceeds the standard at the time it
is initially tested or there is a desire to increase the margin to the
standard for whatever reason. Table IV-3 shows these three different
examples for nvPM LTO Mass.
Table IV-3--Impact of the Number of Engines Tested on Resulting Characteristic Level
----------------------------------------------------------------------------------------------------------------
Number of Measured nvPM
Number of engines tested tests per LTO Mass (mg/ Characteristic Characteristic
engine kN) factor level (mg/kN)
----------------------------------------------------------------------------------------------------------------
1............................................... 3 100 0.7194 139.005
3............................................... 1 100 0.8858 112.892
10.............................................. 1 100 0.9375 106.667
----------------------------------------------------------------------------------------------------------------
[[Page 72333]]
5. Derivative Engines for Emissions Certification Purposes
Aircraft engine types can remain in production for many years and
be subject to numerous modifications during their production life. As
part of the certification process for any change, the type certificate
applicant will need to show if the change will have an impact the
engine emissions. While some of these changes could impact engine
emissions rates, many of them will not. To simplify the certification
process and reduce burden on both type certificate applicant and
certification authorities, ICAO developed criteria to determine whether
there has been an emissions change that requires new testing. Such
criteria already exist at ICAO and in the EPA regulations for gaseous
and smoke standards.
ICAO recommends \123\ that if the characteristic level for an
engine was type certificated at a level that is at or above 80 percent
of the PM mass, PM number, or PM mass concentration standard, the type
certificate applicant would be required to test the proposed derivative
engine. If the engine is below 80 percent of the standard, engineering
analysis can be used to determine new emission rates for the proposed
derivative engines. The EPA is implementing these ICAO recommended
practices in this final rule as the regulatory standard in the United
States.
---------------------------------------------------------------------------
\123\ ICAO, 2020, Environmental Technical Manual, Doc 9501,
Volume II--Procedures for the Emissions Certification of aircraft
Engines, Fourth Edition, Section 2, Part III, Chapter 2.
---------------------------------------------------------------------------
ICAO evaluated the measurement uncertainty to develop criteria for
determining if a proposed derivative engine's emissions are similar to
the previously certificated engine's emissions. The EPA is adopting
these ICAO criteria in this final rule.\124\
---------------------------------------------------------------------------
\124\ Id.
---------------------------------------------------------------------------
For PM mass measurements described in Section IV.A, the following
values apply:
<bullet> 80 mg/kN if the characteristic level for
nvPM<INF>mass</INF> emissions is below 400 mg/kN.
<bullet> <plus-minus>20% of the characteristic level if the
characteristic level for nvPM<INF>mass</INF> emissions is greater than
or equal to 400 mg/kN.
For PM number measurements, described in Section IV.B, the
following values apply:
<bullet> 4x10\14\ particles/kN if the characteristic level for
nvPM<INF>num</INF> emissions is below 2x10\15\ particles/kN.
<bullet> <plus-minus>20% of the characteristic level if the
characteristic level for nvPM<INF>num</INF> emissions is greater than
or equal to 2x10\15\ particles/kN.
For PM mass concentration measurements described in Section IV.C,
the following values apply:
<bullet> <plus-minus>200 [mu]g/m\3\ if the characteristic level of
maximum nvPM mass concentration is below 1,000 [mu]g/m\3\.
<bullet> <plus-minus>20% of the characteristic level if the
characteristic level for maximum nvPM mass concentration is at or above
1,000 [mu]g/m\3\.
If a type certificate applicant can demonstrate that the engine's
emissions are within these ranges, then new emissions rates will not
need to be developed and the proposed derivative engine for emissions
certification purposes will keep the existing emissions rates.
If the engine is not determined to be a derivative engine for
emissions certification purposes, the type certificate applicant will
need to certify the new emission rates for the engine.
E. Annual Reporting Requirement
In 2012, the EPA adopted an annual reporting requirement as part of
a rulemaking to adopt updated aircraft engine NO<INF>X</INF>
standards.\125\ This provision, adopted into 40 CFR 87.42, requires the
manufacturers of covered engines to annually report data to the EPA
which includes information on engine identification and
characteristics, emissions data for all regulated pollutants, and
production volumes. In 2018, the EPA issued an information collection
request (ICR) which renewed the existing ICR and added PM information
to the list of required data.<SUP>126</SUP> <SUP>127</SUP> However,
that 2018 ICR was not part of a rulemaking effort, and the new PM
reporting requirements were not incorporated into the CFR at that time.
Further, that 2018 ICR is currently being renewed (in an action
separate from this rulemaking), and the EPA is including as part of
that effort some additional data elements to the ICR (specifically, the
emission indices for HC, CO, and NO<INF>X</INF> at each mode of the LTO
cycle).<SUP>128</SUP> <SUP>129</SUP> The EPA is now formally
incorporating all aspects of that ICR, as proposed to be renewed, into
40 CFR 1031.150. It is important to note that the incorporation of the
PM reporting requirements into the CFR will not create a new
requirement for the manufacturers of aircraft engines. Rather, it will
simply incorporate the existing reporting requirements (as proposed to
be amended and renewed in a separate action) into the CFR for ease of
use by having all the reporting requirements readily available in the
CFR.
---------------------------------------------------------------------------
\125\ 77 FR 36342 (June 18, 2012).
\126\ 83 FR 44621 (August 31, 2018).
\127\ U.S. EPA, Aircraft Engines--Supplemental Information
Related to Exhaust Emissions (Renewal), OMB Control Number 2060-
0680, ICR Reference Number 201809-2060-08, December 17, 2018.
Available at <a href="https://www.reginfo.gov/public/do/PRAViewICR?ref_nbr=201809-2060-008">https://www.reginfo.gov/public/do/PRAViewICR?ref_nbr=201809-2060-008</a>, last accessed June 8, 2022.
\128\ Proposed Information Collection Request; Comment Request;
Air Emissions Reporting Requirements (Renewal); EPA ICR No. 2170.08,
OMB Control No. 2060-0580, 86 FR 24614 (May 7, 2021).
\129\ Documentation and Public comments are available at:
<a href="https://www.regulations.gov/docket/EPA-HQ-OAR-2016-0546">https://www.regulations.gov/docket/EPA-HQ-OAR-2016-0546</a>, last
accessed June 8, 2022.
---------------------------------------------------------------------------
The EPA uses the collection of information to help conduct
technology assessments, develop aircraft emission inventories (for
current and future inventories), and inform our policy decisions--
including future standard-setting actions. The information enables the
EPA to further understand the characteristics of aircraft engines that
are subject to emission standards--and engines subject to the PM
emission standards--and engines' impact on emission inventories. In
addition, the information helps the EPA set appropriate and achievable
emission standards and related requirements for aircraft engines.
Annually updated information helps in assessing technology trends and
their impacts on national emissions inventories. Also, it assists the
EPA to stay abreast of developments in the aircraft engine industry.
As discussed in Section VII, the EPA is finalizing the proposal to
migrate the existing 40 CFR part 87 regulatory text to a new 40 CFR
part 1031. This effort includes clarifying portions of the regulatory
text for ease of use. In the old 40 CFR 87.42(c)(6), the regulatory
text did not specifically spell out some required data, but instead
relied on incorporation by reference of ICAO Annex 16, Volume II's data
reporting requirements and listed the data from this Annex that is not
required by the EPA's reporting requirement. For future ease of use, 40
CFR 1031.150 explicitly lists all the required items rather than
continuing the incorporation by reference approach in the existing
reporting regulations. Finally, the EPA is incorporating by reference
Appendix 8 of Annex 16, Volume II, which outlines procedures used to
estimate measurement system losses, which are a required element of the
reporting provisions.
F. Response to Key Comments
The EPA received numerous comments on the proposed rulemaking
[[Page 72334]]
which are summarized in the Response to Comments document along with
the EPA's responses to those comments. Comments in their entirety are
available in the docket for this rulemaking action. The following
sections summarize the comments related to the stringency of the
standards and the EPA's response to these comments. Some adverse
comments are addressed more fully in the Response to Comments document.
1. Comments in Support of the Proposed Standards
Comment summary: Some commenters stated that the proposed standards
adhere to the statutory requirements of CAA section 231. They say that
the proposed standards are well supported by an extensive
administrative record. The commenters point out that the D.C. Circuit
ruled in 2007 that CAA section 231 confers a broad degree of discretion
on the EPA in setting aircraft engine emission standards.\130\
---------------------------------------------------------------------------
\130\ National Association of Clean Air Agencies v. EPA, 489
F.3d 1221, 1229-30 (D.C. Cir. 2007) (``When Congress enacted Sec.
231 providing that the Administrator could, `from time to time,' act
`in his judgment,' as `he deems appropriate,' it conferred broad
discretion to the Administrator to weigh various factors in arriving
at appropriate standards.'').
---------------------------------------------------------------------------
Response: EPA is finalizing the standards as proposed. We agree
that the proposed standards, as well as the final standards, satisfy
our statutory obligations and are well-supported. The EPA acknowledges
that the D.C. Circuit recognized the EPA's broad authority in CAA
section 231 in National Association of Clean Air Agencies v. EPA, 489
F.3d 1221, 1229-30 (D.C. Cir. 2007) (NACAA).
Comment summary: Several commenters expressed their support of the
EPA adopting PM standards that match the international PM standards
because doing so is vital to the competitiveness of U.S. industry and
regulatory certainty. They say it would protect U.S. jobs and
strengthen the U.S. aviation industry by ensuring the global acceptance
of U.S.-manufactured aircraft engines. They also say it will make sure
U.S.-manufactured aircraft engines are available to aircraft
manufacturers and U.S. airlines, while enabling U.S. airlines to obtain
aircraft and aircraft engines at market-driven, competitive prices.
Response: The EPA agrees this rule has the benefit of helping to
ensure the acceptance of U.S.-manufactured aircraft engines by member
States, aircraft (airframe) manufacturers, and airlines around the
world. The EPA notes that under the terms of the Chicago Convention,
ICAO member States must recognize as valid certificates of
airworthiness issued by other ICAO member States, provided the
requirements under which such certificates were issued are as least as
stringent as the minimum ICAO standards.\131\
---------------------------------------------------------------------------
\131\ ICAO, 2006: Convention on International Civil Aviation,
Article 33, Ninth Edition, Document 7300/9.
---------------------------------------------------------------------------
Comment summary: Some commenters urged the EPA to promptly issue
the final rule with the standards matching the international standards.
They say that this EPA rulemaking and the subsequent FAA certification
rulemaking must be completed to start the certification process in the
United States. Thus, they believe that prompt EPA action is necessary
to provide sufficient time for FAA to promulgate their certification
rulemaking and U.S. aircraft engine manufacturers to conduct the
lengthy and expensive steps to demonstrate compliance with the
standards, for all aircraft engines that will be in-production in 2023.
They note that January 1, 2023, is the implementation date for the ICAO
standards.
Response: The EPA acknowledges that the international effective
date for the ICAO mass concentration standards was January 1, 2020, and
that the international effective date for the mass and number standards
is January 1, 2023. The EPA also acknowledges that FAA will need to
conduct a separate, subsequent certification rulemaking process to
implement the EPA's PM standards finalized in this action.
In this action, the EPA is aiming to minimize disruption by
finalizing this action before the January 1, 2023, the international
effective date of the PM mass and number standards.
For comparison, the EPA notes the EPA finalized the domestic GHG
standards for airplanes on January 11, 2021, after the international
effective date for new type planes; \132\ however, disruption was
avoided in practice because no manufacturers applied to FAA for a type
certificate for a new type design airplane between January 1, 2020, and
January 11, 2021.
---------------------------------------------------------------------------
\132\ CAEP/10 airplane CO<INF>2</INF> standards apply to new
type design airplanes for which the application for a type
certificate was or will be submitted on or after January 1, 2020,
some modified in-production airplanes on or after January 1, 2023,
and all applicable in-production airplanes manufactured on or after
January 1, 2028.
---------------------------------------------------------------------------
Comment summary: Some commenters state that the proposed standards
are identical to ICAO's aircraft engine PM standards and that adopting
them is consistent with the 1944 Chicago Convention treaty obligations.
They say that these standards continue the long collaborative tradition
between the EPA and ICAO. The commenters say that the objective of the
Chicago Convention is to foster global cooperation and encourage an
atmosphere where international civil aviation could be developed in a
safe and orderly manner, while being operated soundly and economically.
The commenters say that, with both the FAA and the EPA playing key
leadership roles, it was only after significant deliberation and
technical and economic analyses that CAEP agreed to the ICAO PM
standards. The commenters say that the EPA's adoption of standards that
align with ICAO standards supports international harmonization and
regulatory uniformity.
Response: The EPA agrees adopting the PM standards in this action
satisfies the United States' treaty obligations under the Chicago
Convention. The EPA also agrees that the EPA and the FAA had key
leadership roles in the ICAO PM standard-setting process, and the EPA
recognizes the significant deliberations and economic analyses that
occurred in CAEP. The EPA agrees that this action promotes
international cooperation and harmonization.
Comment summary: Some commenters say that the standards are
consistent with the CAEP terms of reference which provide that
standards be technologically feasible, economically reasonable,
environmentally beneficial, and balanced against interdependencies
(aircraft noise and competing emission reductions of other pollutants,
such as NO<INF>X</INF>). The commenters say that the CAEP terms of
reference align well with the considerations in CAA section 231, and
ICAO's assessment of each of the criteria of the terms of reference is
directly related to the decisions the EPA must make when issuing
aircraft engine emission standards. The commenters assert that CAA
section 231(b) requires that aircraft engine emission standards allow
sufficient lead time for the development of the necessary technology,
while giving consideration of the cost to comply within this time
period.
Response: The EPA agrees that the final standards are consistent
with the CAEP terms of reference and that the standards also meet the
requirements of CAA section 231. The EPA would not adopt ICAO standards
domestically without exercising the Agency's own independent evaluation
of appropriate domestic standards under CAA section 231, which is what
the EPA has done in
[[Page 72335]]
this rulemaking. Any domestic aircraft engine standards adopted by the
EPA must comport with the requirements in CAA section 231.
Comment summary: Some commenters say that CAA section
231(a)(2)(B)(ii) expressly prohibits changes in aircraft engine
emission standards that ``would significantly increase noise and
adversely affect safety.'' The commenters point out that, as the EPA
describes in the proposed rulemaking, ICAO/CAEP evaluates
``technological feasibility'' using the Technology Readiness Level
(``TRL'') scale and deems technologies that have attained TRL8 (defined
as the ``actual system completed and `flight qualified' through test
and demonstration'') to be ``technologically feasible.'' Therefore, the
commenters conclude, the use of TRL8 to evaluate ``technological
feasibility'' makes sure aircraft engine emission standards reflect
what technologies can safely deliver, instead of hypothetical
``technology forcing'' standards that could pose a potential threat to
air safety.\133\
---------------------------------------------------------------------------
\133\ Any reference to technology-forcing standards in this
rulemaking is not based on the level of the final PM standards, but
it is intended to respond to comments.
---------------------------------------------------------------------------
Response: The EPA agrees that TRL8 \134\ is an adequate and
appropriate criteria for identifying proven technologies that are
demonstrably safe and of an acceptable noise level for purposes of this
rulemaking. The EPA relies on TRL8 to support the PM standards
finalized in this rule because TRL8 was used to justify the PM
standards by ICAO, as described in Section VI.B. ICAO treats TRL8 as a
proxy for what is technologically feasible in the course of
establishing new international standards. This conservative approach
allows ICAO to ensure that all technology being considered is safe and
of acceptable noise level without having to conduct additional
evaluation of specific technologies. The EPA agrees this use of TRL8 is
a valid means for ICAO to develop standards that will, by definition,
be based on technologies that have been proven safe, of acceptable
noise level, and technologically feasible. The EPA also agrees that
ICAO's use of TRL8 means that technologies considered have been proven
safe and of an acceptable noise level, and therefore, that the final PM
standards do not adversely affect safety and do not significantly
increase noise. In setting the international standards, ICAO considered
the emissions performance of aircraft engines assumed to be in-
production on the implementation date for the PM mass and number
standards, January 1, 2023. Thus, the technology was already
demonstrated to be safe and of acceptable noise levels for these
standards, and ICAO did not view that a new safety and noise analysis
was necessary.
---------------------------------------------------------------------------
\134\ As described in Section VI.B, TRL is a measure of
Technology Readiness Level. CAEP has defined TRL8 as the ``actual
system completed and `flight qualified' through test and
demonstration.'' TRL is a scale from 1 to 9, TRL1 is the conceptual
principle, and TRL9 is the ``actual system `flight proven' on
operational flight.'' The TRL scale was originally developed by
NASA. ICF International, CO2 Analysis of CO2-Reducing Technologies
for Aircraft, Final Report, EPA Contract Number EP-C-12-011, see
page 40, March 17, 2015.
---------------------------------------------------------------------------
However, in the EPA's view, ICAO's use of TRL8 to define
technological feasibility is not the only means to ensure a standard
does not adversely affect safety and does not significantly increase
noise. The EPA does not view TRL8 to represent the most stringent level
of technology that could be required in an EPA aircraft standard
setting rulemaking. Nor does the EPA agree with the premise that
standards based on technology below TRL8 would necessarily be
technology forcing or inherently have a negative effect on safety and
noise. In establishing U.S. aircraft engine emission standards, the EPA
is not constrained to ICAO's definition of technological feasibility in
assessing appropriate aircraft engine standards under CAA section
231(a). See NACAA, 489 F.3d at 1229-30. In fact, the EPA has adopted
technology-forcing standards under CAA section 231 in the past and
found them to be safe and not to significantly increase noise.\135\ In
the future, if the EPA were to consider setting emission standards
based on technology that was not yet at TRL8 or not expected to be at
TRL8 by the implementation date of the standards,\136\ the Agency, just
as it did in this action, in consultation with the FAA, would evaluate
the safety and noise impact (also lead time and cost) of such standards
before making a determination in this regard. CAA section 231(a)(2)(B)
and (a)(3). Any assessment of safety and noise (also lead time and
cost) in the context of hypothetical technology-forcing standards would
have to occur in the context of the specific standards under
consideration.
---------------------------------------------------------------------------
\135\ See 38 FR 19088 (July 17, 1973); 41 FR 34722 (August 16,
1976).
\136\ As described in Section VI.B, for the ICAO PM standard
setting, ICAO referred to technical feasibility as any technology
demonstrated to be safe and airworthy proven to Technology Readiness
Level 8 and available for application over a sufficient range of
newly certificated aircraft. This means that the ICAO analysis that
informed the international standard considered the emissions
performance of aircraft engines assumed to be in-production on the
ICAO implementation date for the PM mass and number standards,
January 1, 2023.
---------------------------------------------------------------------------
2. Comments in Support of More Stringent Standards
Comment summary: Several commenters were dissatisfied with the
level of stringency of the PM standards. One commenter argued that CAA
section 231 requires the EPA to adopt technology-forcing standards.
Other comments argued CAA section 231 requires the EPA to set standards
according to expectations of the development of technology over time.
Some commenters say that, at a minimum, the EPA should establish
standards that reduce emissions based on available engine technology. A
number of commenters supported these arguments by pointing to the text
of the statute, the underlying legislative intent, legislative history,
and the purpose of the CAA.
Response: The statutory-based arguments presented by commenters
that the level of stringency of the PM standards are not authorized by
CAA section 231 import requirements into the statute that do not exist.
As described in Section II.A, CAA section 231(a)(2)(A) directs the
Administrator of the EPA to, from time to time, propose aircraft engine
emission standards applicable to the emission of any air pollutant from
classes of aircraft engines which in the Administrator's judgment
causes or contributes to air pollution that may reasonably be
anticipated to endanger public health or welfare. CAA section 231(a)(3)
provides that after the EPA proposes standards, the Administrator shall
issue such standards ``with such modifications as he deems
appropriate.'' CAA section 231(b) requires that any emission standards
``take effect after such period as the Administrator finds necessary .
. . to permit the development and application of the requisite
technology, giving appropriate consideration to the cost of compliance
during such period.'' The D.C. Circuit has held that the delegation of
authority in CAA section 231 ``is both explicit and extraordinarily
broad'' and that the text confers ``broad discretion . . . to weigh
various factors in arriving at appropriate standards.'' NACAA, 489 F.3d
1221, 1229-30.
The statutory language of CAA section 231 is not identical to other
provisions in the CAA that direct the EPA to establish technology-based
standards. CAA section 231(a) states that the EPA must ``issue proposed
emission standards applicable to the emission of any air pollutant''
from aircraft engines
[[Page 72336]]
and to finalize ``such regulations'' with those modifications the EPA
``deems appropriate.'' CAA section 231(a)(2)(A) and (a)(3). This
language is in contrast to Congress' direction in other parts of the
Act, where it required the EPA to set standards that achieve a
particular degree of emission reduction or environmental or public
health protection. For example, in setting technology-based emission
standards for hazardous air pollutants under CAA section 112(d)(2) and
(3), the EPA must ``require the maximum degree of reduction . . . that
the Administrator . . . determines is achievable,'' taking into account
cost and non-air quality health and environmental impacts. CAA section
112(d)(2). Those standards also ``shall not be less stringent than''
explicitly prescribed levels. CAA section 112(d)(3). Health- and
environmental quality-based NAAQS under CAA section 109 must be set at
levels ``requisite to protect the public health'' and ``requisite to
protect the public welfare from any known or anticipated adverse
effects associated with the presence of [the] air pollutant in the
ambient air.'' CAA section 109(b)(1) and (2). When regulating certain
pollutants from motor vehicles and nonroad engine emissions under CAA
sections 202(a)(3) and 213(a)(3) and (5), the EPA's standards must
``reflect the greatest degree of emission reduction achievable . . . ,
giving appropriate consideration to cost, energy, and safety factors
associated with the application of such technology.'' CAA sections
202(a)(3) and 213(a)(3) and (5).
CAA section 231 lacks comparable language requiring it to meet a
particular threshold of protectiveness, emission reduction, or
technological stringency, despite this clear evidence that Congress
knew how to impose such obligations when it wished. See generally CAA
section 231. ``Where Congress uses certain language in one part of a
statute and different language in another, it is generally presumed
that Congress acts intentionally.'' Nat'l Fed'n of Indep. Bus. v.
Sebelius, 567 U.S. 519, 544 (2012); Sosa v. Alvarez-Machain, 542 U.S.
692, 711 n.9 (2004) (citing a treatise on statutory construction and
calling this principle the ``usual rule'' of judicial interpretation).
In certain respects, the EPA's authority is broader than it is under
other CAA provisions, in that the EPA is not required in setting
aircraft emission standards to achieve a specified degree of emissions
reduction.
Some commenters also presented a textual comparison of the House
and Senate bills to conclude that Congress intended for CAA section 231
to be based on a consideration of pollution impacts and technological
feasibility because the final CAA section 231(a)(1) required the EPA to
conduct a study within 90 days after December 31, 1970 of air
pollutants from aircraft to determine impact on air quality and
technological feasibility of controlling such pollutants. S. Rep. No.
91-1196, at 24, 1 Leg. Hist. at 424; H.R. Rep. No. 91-1783, at 55
(Conf. Rep.). One commenter alleged this means ``the necessary premise
[is] that such study should inform the standards themselves.'' \137\
However, the study requirement in CAA section 231(a)(1) does not
establish a requirement for aircraft engine standards to be forward-
looking technology-based regulation. That provision required EPA to
conduct a one-time ``study and investigation'' ``to determine'' the
extent of aircraft emissions' impacts on air quality and the
feasibility of controlling them ``[w]ithin 90 days after December 31,
1970.'' The single study required in CAA section 231(a)(1) is not a
continuing obligation that pertains to each exercise of the standard-
setting authority under CAA section 231(a)(2) and (3), which contain no
discussion of technological feasibility and under which standards are
set and may be revised ``from time to time.'' Cf. Sierra Club, 325 F.3d
374, 377 (D.C. Cir. 2003) (holding that a provision requiring EPA to
set standards ``based on'' such a study did not make the validity of
the standards dependent on their connection to that study).
---------------------------------------------------------------------------
\137\ Comments of California, Connecticut, Illinois, Maryland,
Massachusetts, New Jersey, New York, Oregon, Pennsylvania, Vermont,
Washington, and Wisconsin at 13. See also Comment of Sierra Club at
7-8.
---------------------------------------------------------------------------
The commenters also quoted to a Senate report accompanying the CAA
1970 amendment Senate bill to suggest CAA section 231 requires
standards to be based on the degree of harm caused by aircraft
pollution and the technology that can be developed in the future to
reduce it. The statement cited by commenters from the Senate Report
does not constrain the EPA where the plain text of the statute does
not, and where Congress knew how, but declined, to make such
constraints mandatory on the Agency. ``Congress' authoritative
statement is the statutory text, not the legislative history.'' Chamber
of Com. Of U.S. v. Whiting, 563 U.S. 582, 599 (2011) (quoting Exxon
Mobil Corp. v. Allapattah Services, Inc., 545 U.S. 546, 568 (2005)
(internal quotation marks omitted). Further, the NACAA Court rejected
an argument that similar statements in the 1970 Senate Report
established Congress' intent that the EPA prioritize forward-looking
standards. NACAA, 489 F.3d at 1229-30; Sierra Club v. EPA, 325 F.3d
374, 379-380 (D.C. Cir. 2003).
The EPA's interpretation of CAA section 231 is not categorically at
odds with the Clean Air Act's general protective purpose. The Act's
general goal of reducing air pollution does not, in itself, prescribe
regulatory factors for specific programs, nor does it restrict the
EPA's discretion as to how best effectuate that goal in a specific
action or in a regulatory program over time. Accordingly, while the
EPA's discretion under CAA section 231 would allow it to select more
stringent standards when appropriate, it does not mandate that the EPA
elevate pollution reduction over all relevant factors in the
consideration of any particular aircraft standard. See NACAA, 489 F.3d
at 1229-30.
The final PM standards fall squarely within the EPA's statutory
authority under CAA section 231 to promulgate. As described in Section
I.B.2 and the introductory text of Section IV, in proposing and
adopting the final PM standards, the EPA considered the statutory
requirements of CAA section 231. The EPA also took into account the
need to control PM emissions, the importance of international
harmonization, avoiding adverse impacts that could result from delaying
adoption of PM standards at least as stringent as ICAO's PM standards,
and gaining experience from the novel approach to implementing PM
standards. Further, based on the EPA's independent view that technology
at the TRL8 has been demonstrated to be safe and of an acceptable
noise-level, the EPA is confident that the final standards will not
significantly increase noise or adversely affect safety. The EPA
reached the same conclusion as ICAO that a new noise and safety
analysis was not necessary. For the same reasons, the EPA believes
sufficient lead time has been provided since the technology has already
been developed. Costs information for the standards is described in
Section VI.D. Based on this assessment, the EPA concludes that it is
reasonable to finalize PM standards that match the international
standards in scope, stringency, and effective date.
Additional legal issues raised by these comments are addressed in
the Response to Comments document.
Comment summary: Some commenters claim the EPA has an obligation to
consider the feasibility, costs, and benefits of more stringent
standards, including technology-forcing standards, or at least explain
why it did
[[Page 72337]]
not do so. A few commenters proposed suggestions to alternative PM
controls such as de-rated takeoff, accelerated implementation of
Optimized Profile Descents, reduced power during taxiing, improved taxi
time, and reduced usage of auxiliary power units (APUs).
Response: The focused scope of the EPA's proposed PM standards was
informed by the January 1, 2023, international effective date for the
mass and number PM standards, as well as the other considerations
identified elsewhere throughout this preamble. The EPA does not believe
it would be feasible to repropose more stringent PM standards and also
meet the international effective date of the new mass and number
standards. Should the United States miss the January 1, 2023, deadline,
U.S. airplane and engine manufacturers could be forced to seek PM
emissions certification from an aviation certification of another
country to market and operate their airplanes and engines
internationally. The United States would also miss its obligations
under the Chicago Convention.
The EPA believes that the limited scope of the proposal is
permissible under CAA section 231 and, based on the plain language of
the statute, disagrees with the premise that the statute requires the
Agency to propose multiple levels of stringency of standards. To the
extent commenters identified specific alternative levels of stringency
they would prefer, the comments did not provide sufficient information
about safety, noise, lead time, and costs of those alternatives to
support the EPA finalizing more stringent standards in this rulemaking.
In light of the reasons the EPA has provided for adopting the PM
standards as proposed, the EPA does not view these ``modifications''
requested by commenters to be ``appropriate'' to incorporate into the
PM standards adopted in this rulemaking. See CAA section 231(a)(3). The
EPA's current and intended future work related to addressing PM
emissions from aircraft engines is described in Section I.C.
A number of commenters also provided suggested ideas for
alternative methods to regulating PM emissions (e.g., de-rated takeoff,
reduced power during taxiing, and improved taxi time). The EPA has
carefully reviewed the alternatives raised by the commenters, but has
decided not to adopt them in this final rulemaking. The EPA does not
believe it would be feasible to assess the legal, technical, and policy
issues raised by suggested alternatives put forward by commenters;
repropose standards; take public comment; and meet the international
effective date of January 1, 2023. More specific comments related to
suggested alternative PM controls are addressed in the Response to
Comments document.
Comment summary: According to some commenters, the EPA
impermissibly factored international harmonization, adverse impacts on
U.S. industry, or other non-statutory considerations into its rationale
supporting the PM standards.
Response: The EPA's past practice and the D.C. Circuit's holding in
NACAA that the EPA's historical approach of taking international
harmonization into account in setting domestic standards as not
``manifestly contrary to the statute'', NACAA, 489 F.3d at 1230, affirm
that the EPA's broad discretion includes the ability to weigh
considerations such as international harmonization and the competitive
effects of the EPA's standards on international aviation. Nothing in
CAA section 231 precludes such considerations. Aircraft and their
engines are manufactured and sold around the world, and routinely
operate in international airspace. Furthermore, CAA section 231 does
not list or dictate the EPA's consideration of particular factors and
enables the EPA to identify and apply relevant considerations in
determining what standards are ``appropriate''. CAA section 231(a)(3).
The D.C. Circuit rejected an argument similar to the commenters' in
NACAA: ``Finding nothing in the text or structure of the statute to
indicate that the Congress intended to preclude the EPA from
considering `[factors other than air quality],' we refused to infer
from congressional silence an intention to preclude the agency from
considering factors other than those listed in a statute.'' 489 F.3d at
1230 (quoting George E. Warren Corp. v. EPA, 159 F.3d 61, 623-24 (D.C.
Cir. 1998)). Moreover, the Chicago Convention, ratified by the United
States, has the force of Federal law, and therefore, the EPA acts
appropriately in implementing our Clean Air Act authorities in a manner
that is harmonious and consistent with the Chicago Convention and the
United States' international obligations under the treaty.
Having invested significant effort and resources, working with the
FAA and the Department of State, to gain international consensus within
ICAO to adopt the international PM standards for aircraft engines, the
EPA believes that meeting the United States' obligations under the
Chicago Convention by aligning domestic standards with the ICAO
standards, rather than adopting more stringent standards, will have
substantial benefits for future international cooperation on aircraft
engine emission standards, and such cooperation is the key for
achieving worldwide emission reductions. Deviating from the
international PM standards could undermine future efforts by the United
States to seek international consensus on aircraft emission standards
in general, including more stringent future standards for PM. Reaching
this conclusion is not tantamount to a determination that it would
never be appropriate for the EPA to adopt more stringent PM standards
than ICAO's standards. However, at this time, the EPA finds it
appropriate to finalize the standards as proposed.
In addition, the ICAO applicability date of the mass and number
standards of January 1, 2023, is fast approaching. The U.S. aircraft
engine manufacturers, aircraft manufacturers, and airlines are urging
the EPA to promptly promulgate this final rulemaking to adopt ICAO's
standards, which were adopted back in 2017 and 2020, so they can build
(and sell) or have access to U.S. engines to remain competitive in the
global marketplace. Furthermore, the EPA understands that U.S. aircraft
engine manufacturers need time to certify their products, after the
subsequent FAA rulemaking to enforce the standards, to ensure the
aircraft engines comply with standards. Also, the EPA did not conduct
the analyses needed to support more stringent standards in the proposed
rulemaking, or otherwise develop a sufficient record for more stringent
standards, that would be necessary to support finalizing such standards
in this final rule. We do not believe we could finalize more stringent
standards without conducting significant additional analyses and
undertaking a new round of notice and comment, which would certainly
cause a significant delay in meeting the United States' obligations
under the Chicago Convention. We have decided that the most appropriate
course, under CAA section 231, is to adopt aircraft engine PM standards
that are harmonized with the standards adopted by ICAO in 2017 and
2020.
In determining what final PM standards are appropriate under CAA
section 231 and after consultation with FAA, the EPA considered the
level of standards that could be met with the application of requisite
technology within the necessary period of time that would allow the
United States to meet its obligations under the Chicago Convention to
at least match the ICAO standards, and gave appropriate consideration
to the cost of compliance within this period. This determination also
took into account the requirement
[[Page 72338]]
that EPA's revised standards not significantly increase noise and
adversely affect safety.
Comment summary: Some commenters argued that the EPA's position
that it would be appropriate to gain experience from implementation of
the novel approach to implementing PM standards before considering
whether to adopt more stringent regulations is arbitrary and
capricious.
Response: As described the introductory paragraphs of Section IV,
these final standards change the approach to regulating aircraft engine
PM emissions from past smoke measurements to the measurement of mass
and number for the first time for U.S. manufacturers, and international
regulatory uniformity and certainty are key elements for these
manufacturers as they become familiar with adhering to these standards
and test procedures. Further, some manufacturers are still adapting to
how best control aircraft engine PM since they designed recent in-
production engines to optimize NO<INF>X</INF> control, as explained in
the succeeding paragraphs.\138\ We think that considering the novelty
of these approaches and the industry's response to them falls well
within our discretion. Moreover, they also pertain to the statutory
directive to consider the lead time necessary for the development and
application of the requisite technology. See CAA section 231(b).
---------------------------------------------------------------------------
\138\ ICAO, 2019: Independent Expert Integrated Technology Goals
Assessment and Review for Engines and Aircraft, Document 10127. It
is found on page 34 of the English Edition of the ICAO Products &
Services 2022 Catalog and is copyright protected; Order No. 10127.
---------------------------------------------------------------------------
Comment summary: Some commenters say that proposed standards are
far less stringent than PM emission levels that existing aircraft
engine technologies already achieve. Some commenters assert that more
stringent PM standards compared to the proposed standards are feasible
for in-production and new type design aircraft engines. Some commenters
argue that the proposed PM standards are not anti-backsliding. These
comments say that all in-production engines already meet the proposed
standards for in-production engines and most meet the proposed
standards for new type design engines by a considerable margin;
therefore, no backsliding could reasonably happen absent these
standards.
Response: While it may be true that more stringent PM standards
compared to the final standards are feasible for some in-production and
new type design aircraft engines, for the reasons explained in the
proposal and again in this final rule the EPA does not consider more
stringent standards than those adopted in this action, applicable to
all in-production and new type design engines, to be appropriate at
this time. Additionally, the EPA did not propose more stringent
standards, and the existing record that has been developed does not
support finalizing more stringent standards absent significant
additional analyses.
The EPA disagrees that the standards are not anti-backsliding.
Although the PM mass concentration standard is replacing the smoke
standard for some engines, the PM mass and number standards are the
first of their kind. In that regard, PM mass and number are currently
unregulated from aircraft engines and the standards finalized in this
action represent a new regulatory backstop of those two forms of
previously uncontrolled PM emissions. Further, all three PM standards
will prevent backsliding by ensuring that all new type design and in-
production aircraft engines will not exceed those regulatory levels in
the future.
CAEP meets triennially, and in the future, we anticipate ICAO/CAEP
considering more stringent aircraft engine PM standards. The U.S.
Interagency Group on International Aviation (IGIA) facilitates
coordinated recommendations to the Secretary of State on issues
pertaining to international aviation (and ICAO/CAEP), and the FAA is
the chair of IGIA. Representatives of domestic states, non-governmental
organizations, and industry can participate in IGIA to provide input
into future standards for ICAO/CAEP. U.S. manufacturers will be better
prepared for any future standard change due to their experience with
measuring nvPM mass and number for the first time for these final
standards. The PM standards adopted in this rulemaking, within the
larger context of international aircraft standard-setting, send an
important signal that PM emissions is a factor that manufacturers need
to consider when building aircraft engines now and going forward--with
the anticipation that ICAO/CAEP will consider more stringent PM
standards in the future.
In response to the comments that the standards are far less
stringent than PM emission levels of existing aircraft engine
technologies, the EPA notes that there is a wide range of PM levels for
in-production aircraft engines. As described in Section VI.C, for some
manufacturers new technologies aimed at reducing aircraft engine
NO<INF>X</INF>, which were implemented for in-production engines that
were recently built, also resulted in an order of magnitude reduction
in PM in comparison to most in-service engines. Specifically, the
current lean-burn engines and some advanced Rich-Quench-Lean (RQL)
engines developed for the purpose of achieving low NO<INF>X</INF>
emissions coincidentally provided order of magnitude reductions in PM
emissions in comparison to existing RQL engines.\139\ Other
manufacturers did not develop or implement such technologies that
resulted in such PM reduction, and thus, their recent in-production
aircraft engines are not achieving similar PM control. The final PM
standards are anti-backsliding for these aircraft engines by ensuring
that they will not exceed the final standards in the future. Further,
this information shows that available engine technology includes a wide
range of technologies, and the EPA's final standards are standards that
can be met by all engines expected to be in production by the
implementation date of the PM mass and number standards, January 1,
2023.
---------------------------------------------------------------------------
\139\ ICAO, 2019: Independent Expert Integrated Technology Goals
Assessment and Review for Engines and Aircraft, Document 10127. It
is found on page 34 of the English Edition of the ICAO Products &
Services 2022 Catalog and is copyright protected; Order No. 10127.
---------------------------------------------------------------------------
Comment summary: Some commenters argued that the EPA is not bound
by the Chicago Convention to adopt standards equivalent to ICAO's
standards, and relatedly some commenters asserted the EPA is not
prohibited from adopting standards more stringent than ICAO's
standards. Some comments argued that the EPA cannot allow international
agreements to dictate its domestic regulation of PM from aircraft
engines.
Response: As explained in the introductory text of Section IV and
in Section VI, and reiterated throughout the responses to comments, the
EPA conducted its independent assessment of the appropriateness of the
ICAO standards for domestic application in the United States and finds
it appropriate to adopt domestic PM standards aligned with the
international PM standards in this action. The EPA agrees that the
United States could adopt standards at a different stringency than
ICAO's, even more stringent standards. Under the terms of the Chicago
Convention, ICAO member States must recognize as valid certificates of
airworthiness issued by other ICAO member States, provided the
requirements under which such certificates were issued are as least as
[[Page 72339]]
stringent as the minimum ICAO standards.\140\
---------------------------------------------------------------------------
\140\ ICAO, 2006: Convention on International Civil Aviation,
Article 33, Ninth Edition, Document 7300/9.
---------------------------------------------------------------------------
The need for direct cooperation between countries gave rise to
ICAO, an active regulatory body that sets and revises standards. As
described in Section II.B, ICAO's work on the environment focuses
primarily on those problems that benefit most from a common and
coordinated approach on a worldwide basis, namely aircraft noise and
engine emissions. Compliance with ICAO's standards, including its
emission standards, is essential to ensure acceptance by other
countries as people, aircraft, and cargo move in international
commerce. The EPA recognizes nations have authority to vary from ICAO
standards, provided they give the required notice. Also, the EPA has
not concluded that the unique features of the aviation industry
necessitate a policy to never adopt more stringent emission standards
compared to ICAO standards. However, adopting more stringent PM
standards than ICAO's PM standards, which change the approach to
regulating aircraft engine PM emissions, would risk disruption to
international cooperation. The EPA considered the timing of the ICAO PM
mass and number standards for new type design and in-production
engines, which have a January 1, 2023 implementation date. Given the
limited time frame and potential implications of the EPA not adopting a
standard, the EPA has acted reasonably in this rulemaking by giving
significant weight to the value of international harmonization and to
the fact that, in the EPA's judgment, international harmonization would
promote ongoing cooperation to control global pollution of PM.
Comment summary: Some commenters urged the EPA to withdraw the
proposed rule and issue a proposed rule that would assess the full
range of feasible stringency options and propose emission standards
that reduce aircraft PM emissions.
Response: The EPA is finalizing the PM standards as proposed.
However, as explained in Section I.C, the EPA remains committed to
analyzing this issue and will continue to work with the United States'
international partners to revisit these standards in the future. We do
not believe it would be appropriate to withdraw the proposed rule and
issue a new proposal for the reasons stated in the preceding
paragraphs.
V. Aggregate PM Inventory Methodology and Impacts
The PM emissions inventory is presented here to provide information
on the contribution of aircraft engine emissions to local inventories
as context for this regulatory effort. This PM emissions inventory is
from the aviation portion of the EPA's 2017 National Emissions
Inventory (NEI).<SUP>141 142 143</SUP> The NEI contains comprehensive
emissions data for criteria pollutants and hazardous air pollutants for
mobile, point, and nonpoint sources covering both natural and
anthropogenic contribution to the overall national PM emissions
inventory. For this PM rulemaking, we updated the aviation portion of
the PM emissions inventory using newly available measured data reported
for most in-production engines and an improved approximation method for
engines without measurement data, as described in this section.
---------------------------------------------------------------------------
\141\ 2017 National Emissions Inventory: Aviation Component,
Eastern Research Group, Inc., June 25, 2020, EPA Contract No. EP-C-
17-011, Work Order No. 2-19.
\142\ See section 3.2 for airports and aircraft related
emissions in the Technical Supporting Document for the 2017 National
Emissions Inventory, January 2021 Updated Release.
\143\ U.S. EPA, 2017 National Emissions Inventory (NEI) Data.
---------------------------------------------------------------------------
The inventory is developed from using actual operations at
airports. The number of aircraft operations or landings and takeoffs
affects PM emissions that contribute to the local air quality near
airports. The landing and take-off (LTO) emissions are defined as
emissions between ground level and an altitude of about 3,000 feet.
These LTO emissions directly affect the ground level air quality at the
vicinity of the airport since they are within the local mixing height.
They are composed of emissions during departure operations (taxi-out
movement from gate to runway, aircraft take-off run and climb-out to
3,000 feet), and during arrival operations (approach at or below 3,000
feet down to landing on the ground and taxi-in from runway to gate).
Depending on the meteorological conditions, the emissions will be mixed
with ambient air down to ground level, dispersed, and transported to
areas downwind from the airport with elevated concentration
levels.\144\
---------------------------------------------------------------------------
\144\ A local air quality ``emissions inventory for aircraft
focuses on the emission characteristics of this source relative to
the vertical column of air that ultimately affects ground level
pollutant concentrations. This portion of the atmosphere, which
begins at the earth's surface and is simulated in air quality
models, is often referred to as the mixing zone'' or mixing height.
(page 137.) The air in this mixing height is completely mixed and
pollutants emitted anywhere within it will be carried down to ground
level. (page 143.) ``The aircraft operations of interest within the
[mixing height] are defined as the [LTO] cycle.'' (page 137.) The
default mixing height in the U.S. is 3,000 feet. (EPA, 1992:
Procedures for Emission Inventory Preparation--Volume IV: Mobile
Sources, EPA420-R-92-009.
---------------------------------------------------------------------------
As described in Section III.A, aircraft PM emissions are composed
of both volatile and non-volatile PM (nvPM) components.\145\ With a
precisely controlled air-fuel mixture, a typical aircraft engine yields
combustion products on the order of 27.6 percent water
(H<INF>2</INF>O), 72 percent CO<INF>2</INF>, about 0.02 percent
SO<INF>X</INF>, and only about 0.4 percent incomplete residual
products. These incomplete residual products can be broken down to 84
percent NO<INF>X</INF>, 11.8 percent CO, 4 percent unburned
hydrocarbons (UHC), 0.1 percent PM, and trace amounts of other
products.\146\ Although the PM emissions are a small fraction of total
engine exhaust, the composition and morphology of PM are complex and
dynamic. While the emissions certification test procedures focus only
on measuring non-volatile PM (black carbon), our emissions inventory
includes estimates for volatile PM (organic, lubrication oil residues
and sulfuric acid) as well.
---------------------------------------------------------------------------
\145\ ICAO: 2019, ICAO Environmental Report. A copy of this
document is available in the docket for this rulemaking under
document identification number EPA-HQ-OAR-2019-0660-0022. See pages
100 and 101 for a description of non-volatile PM and volatile PM.
``At the engine exhaust, particulate emissions mainly consist of
ultrafine soot or black carbon emissions. Such particles are called
`non-volatile' (nvPM). They are present at the high temperatures at
the engine exhaust and they do not change in mass or number as they
mix and dilute in the exhaust plume near the aircraft. The geometric
mean diameter of these particles is much smaller than
PM<INF>2.5</INF> (geometric mean diameter of 2.5 Microns) and ranges
roughly from 15nm to 60nm (0.06 Microns). These are classified as
ultrafine particles (UFP).'' (See page 100.) ``The new ICAO standard
is a measure to control the ultrafine non-volatile particulate
matter emissions emitted at the engine exit[.]'' (See page 101.)
``Additionally, gaseous emissions from engines can also condense
to produce new particles (i.e., volatile particulate matter--vPM),
or coat the emitted soot particles. Gaseous emissions species react
chemically with ambient chemical constituents in the atmosphere to
produce the so called secondary particulate matter. Volatile
particulate matter is dependent on these gaseous precursor
emissions. While these precursors are controlled by gaseous
emissions certification and the fuel composition (e.g., sulfur
content) for aircraft gas turbine engines, the volatile particulate
matter is also dependent on the ambient air background
composition.'' (See pages 100 and 101.)
\146\ European Monitoring and Evaluation Programme/European
Environment Agency, Air Pollutant Emission Inventory Guidebook 2019.
---------------------------------------------------------------------------
A. Aircraft Engine PM Emissions Modeling Methodologies
This section describes the nvPM approximation method we used in the
proposed rulemaking, the use of newly available measured nvPM data, and
[[Page 72340]]
improvement to the nvPM approximation method for the final rulemaking.
1. PM Emission Indices Used in the Rulemaking
Measured PM data were not available when the EPA first developed
the 2017 inventory. Thus, to calculate the baseline aircraft engine PM
emissions, we used the First Order Approximation Version 3.0 (FOA3)
method defined in the Society of Automotive Engineers (SAE) Aerospace
Information Report, AIR5715.\147\ For nvPM mass, the FOA3 method is
based on an empirical correlation of Smoke Number (SN) values and the
nvPM mass concentrations of aircraft engines. The nvPM mass
concentration (g/m\3\) derived from SN can then be converted into an
nvPM mass emission index (EI) in gram of nvPM per kg fuel using the
method developed by Wayson et al.\148\ based on a set of empirically
determined Air Fuel Ratios (AFR) and engine volumetric flow rates at
the four ICAO LTO thrust settings (see Table IV-1). Subsequently, the
nvPM mass EI can be used to calculate the nvPM mass for the four LTO
modes with engine fuel flow rate and time-in-mode information. As the
name suggests,
[…truncated; see source link]Indexed from Federal Register on November 23, 2022.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.