[Federal Register Volume 79, Number 81 (Monday, April 28, 2014)]
[Rules and Regulations]
[Pages 23413-23886]
[FR Doc No: 2014-06954]

Vol. 79

Monday,

No. 81

April 28, 2014

Part II

 Environmental Protection Agency

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40 CFR Parts 79, 80, 85, et al.

 Control of Air Pollution From Motor Vehicles: Tier 3 Motor Vehicle
Emission and Fuel Standards; Final Rule

Federal Register / Vol. 79 , No. 81 / Monday, April 28, 2014 / Rules
and Regulations

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 79, 80, 85, 86, 600, 1036, 1037, 1039, 1042, 1048,
1054, 1065, and 1066

[EPA-HQ-OAR-2011-0135; FRL 9906-86-OAR]
RIN 2060-AQ86

Control of Air Pollution From Motor Vehicles: Tier 3 Motor
Vehicle Emission and Fuel Standards

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This action establishes more stringent vehicle emissions
standards and will reduce the sulfur content of gasoline beginning in
2017, as part of a systems approach to addressing the impacts of motor
vehicles and fuels on air quality and public health. The gasoline
sulfur standard will make emission control systems more effective for
both existing and new vehicles, and will enable more stringent vehicle
emissions standards. The vehicle standards will reduce both tailpipe
and evaporative emissions from passenger cars, light-duty trucks,
medium-duty passenger vehicles, and some heavy-duty vehicles. This will
result in significant reductions in pollutants such as ozone,
particulate matter, and air toxics across the country and help state
and local agencies in their efforts to attain and maintain health-based
National Ambient Air Quality Standards. Motor vehicles are an important
source of exposure to air pollution both regionally and near roads.
These vehicle standards are intended to harmonize with California's Low
Emission Vehicle program, thus creating a federal vehicle emissions
program that will allow automakers to sell the same vehicles in all 50
states. The vehicle standards will be implemented over the same
timeframe as the greenhouse gas/fuel efficiency standards for light-
duty vehicles (promulgated by EPA and the National Highway Safety
Administration in 2012), as part of a comprehensive approach toward
regulating emissions from motor vehicles.

DATES: This final rule is effective on June 27, 2014. The incorporation
by reference of certain publications listed in this regulation is
approved by the Director of the Federal Register as of June 27, 2014.

ADDRESSES: EPA has established a docket for this action under Docket ID
No. EPA-HQ-OAR-2011-0135. All documents in the docket are listed on the
www.regulations.gov Web site. Although listed in the index, some
information is not publicly available, e.g., CBI 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 in www.regulations.gov or
in hard copy at the Air and Radiation Docket and Information Center,
EPA/DC, EPA West, Room 3334, 1301 Constitution Ave. NW., Washington,
DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday
through Friday, excluding legal holidays. The telephone number for the
Public Reading Room is<PHONE_NUMBER>, and the telephone number for the
Air Docket is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: JoNell Iffland, Office of
Transportation and Air Quality, Assessment and Standards Division
(ASD), Environmental Protection Agency, 2000 Traverwood Drive, Ann
Arbor MI 48105; Telephone number:<PHONE_NUMBER>; Fax number: (734)
214-4816; Email address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this action apply to me?

    Entities potentially affected by this rule include gasoline
refiners and importers, ethanol producers, ethanol denaturant
producers, butane and pentane producers, gasoline additive
manufacturers, transmix processors, terminals and fuel distributors,
light-duty vehicle manufacturers, independent commercial importers,
alternative fuel converters, and manufacturers and converters of
vehicles between 8,500 and 14,000 lbs gross vehicle weight rating
(GVWR).
    Potentially regulated categories include:

----------------------------------------------------------------------------------------------------------------
                                                                                Examples of potentially
           Category                  NAICS\a\ Code              SIC\b\ Code              affected entities
----------------------------------------------------------------------------------------------------------------
Industry.....................  324110..................  2911....................  Petroleum refineries
                                                                                (including importers).
Industry.....................  325110..................  2869....................  Butane and pentane
                                                                                manufacturers.
Industry.....................  325193..................  2869....................  Ethyl alcohol manufacturing.
Industry.....................  324110, 211112..........  2911, 1321..............  Ethanol denaturant
                                                                                manufacturers.
Industry.....................  211112..................  1321....................  Natural gas liquids
                                                                                extraction and
                                                                                fractionation.
Industry.....................  325199..................  2869....................  Other basic organic chemical
                                                                                manufacturing.
Industry.....................  486910..................  4613....................  Natural gas liquids
                                                                                pipelines, refined petroleum
                                                                                products pipelines.
Industry.....................  424690..................  5169....................  Chemical and allied products
                                                                                merchant wholesalers.
Industry.....................  325199..................  2869....................  Manufacturers of gasoline
                                                                                additives.
Industry.....................  424710..................  5171....................  Petroleum bulk stations and
                                                                                terminals.
Industry.....................  493190..................  4226....................  Other warehousing and storage-
                                                                                bulk petroleum storage.
Industry.....................  336111, 336112..........  3711....................  Light-duty vehicle and light-
                                                                                duty truck manufacturers.
Industry.....................  811111, 811112, 811198..  7538, 7533, 7534........  Independent commercial
                                                                                importers.
Industry.....................  335312, 336312, 336322,   3621, 3714, 3519, 3599,   Alternative fuel converters.
                                336399, 811198.           7534.
Industry.....................  333618, 336120, 336211,   3699, 3711, 3713, 3714..  On-highway heavy-duty engine
                                336312.                                             & vehicle (>8,500 lbs GVWR)
                                                                                manufacturers.
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\a\ North American Industry Classification System (NAICS).
\b\ Standard Industrial Classification (SIC).

    This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by this
action. This table lists the types of entities that EPA is now aware
could potentially be regulated 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 applicability criteria in 40 CFR parts 79,

80, 85, 86, 600, 1036, 1065, and 1066 and the referenced regulations.
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.

B. Did EPA conduct a peer review before issuing this action?

    This regulatory action was supported by influential scientific
information. Therefore, EPA conducted peer reviews in accordance with
OMB's Final Information Quality Bulletin for Peer Review. EPA conducted
several peer reviews in connection with data supporting the Tier 3
program, including new research on the effects of fuel properties
changes (including sulfur effects) on exhaust and evaporative emissions
of Tier 2 vehicles. The refinery-by-refinery cost model was also peer
reviewed. The peer review reports are located in the docket for today's
action, as well as the agency's response to the peer review comments.

Table of Contents

I. Executive Summary and Program Overview
    A. Introduction
    B. Overview of the Tier 3 Program
    1. Major Public Comments and Key Changes From the Proposal
    2. Key Components of the Tier 3 Program
    C. What will the impacts of the standards be?
II. Why is EPA taking this action?
    A. Basis for Action Under the Clean Air Act
    1. Clean Air Act Section 202
    2. Clean Air Act Section 211
    B. Overview of Public Health Impacts of Motor Vehicles and Fuels
    1. Ozone
    2. Particulate Matter
    3. Oxides of Nitrogen and Sulfur
    4. Carbon Monoxide
    5. Mobile Source Air Toxics
    6. Near-Roadway Pollution
    7. Environmental Impacts of Motor Vehicles and Fuels
III. How would this rule reduce emissions and air pollution?
    A. Effects of the Vehicle and Fuel Changes on Mobile Source
Emissions
    1. How do vehicles produce the emissions addressed in this
action?
    2. How will the changes to gasoline sulfur content affect
vehicle emissions?
    B. How will emissions be reduced?
    1. NOX
    2. VOC
    3. CO
    4. Direct PM2.5
    5. Air Toxics
    6. SO2
    7. Greenhouse Gases
    C. How will air pollution be reduced?
    1. Ozone
    2. Particulate Matter
    3. Nitrogen Dioxide
    4. Air Toxics
    5. Visibility
    6. Nitrogen and Sulfur Deposition
    7. Environmental Justice
IV. Vehicle Emissions Program
    A. Tier 3 Tailpipe Emission Standards for Light-Duty Vehicles,
Light-Duty Trucks, and Medium-Duty Passenger Vehicles
    1. How the Tier 3 Program is harmonized with the California LEV
III Program
    2. Summary of the Tier 3 FTP and SFTP Tailpipe Standards
    3. FTP Standards
    4. SFTP Standards
    5. Feasibility of the NMOG+NOX and PM Standards
    6. Impact of Gasoline Sulfur Control on the Effectiveness of the
Vehicle Emission Standards
    7. Other Provisions
    B. Tailpipe Emissions Standards for Heavy-Duty Vehicles
    1. Overview and Scope of Vehicles Regulated
    2. HDV Exhaust Emissions Standards
    3. Supplemental FTP Standards for HDVs
    4. HDV Emissions Averaging, Banking, and Trading
    5. Feasibility of HDV Standards
    6. Other HDV Provisions
    C. Evaporative Emissions Standards
    1. Tier 3 Evaporative Emission Standards
    2. Program Structure and Implementation Flexibilities
    3. Technological Feasibility
    4. Heavy-Duty Gasoline Vehicle (HDGV) Requirements
    5. Evaporative Emission Requirements for FFVs
    6. Test Procedures and Certification Test Fuel
    D. Improvements to In-Use Performance of Fuel Vapor Control
Systems
    1. Reasons for Adding a Leak Test Standard
    2. Nature, Scope and Timing of Leak Standard
    3. Leak Standard Test Procedure
    4. Certification and Compliance
    a. In-Use Verification Program (IUVP) Requirements for the Leak
Standard
    E. Onboard Diagnostic System Requirements
    1. Onboard Diagnostic (OBD) System Regulation Changes--Timing
    2. Revisions to EPA OBD Regulatory Requirements
    3. Provisions for Emergency Vehicles
    4. Future Considerations
    F. Emissions Test Fuel
    1. Gasoline Emissions Test Fuel: Ethanol Content and Volatility
    2. Other Gasoline Emissions Test Fuel Specifications
    3. Flexible Fuel Vehicle Exhaust Emissions Test Fuel
    4. Implementation Schedule
    5. Implications of Emission Test Fuel Changes on CAFE Standards,
GHG Standards, and Fuel Economy Labels
    6. Consideration of Test Fuel for Nonroad Engines and Highway
Motorcycles
    7. CNG and LPG Emissions Test Fuel Specifications
    G. Small Business Provisions
    1. Lead Time and Relaxed Interim Standards
    2. Assigned Deterioration Factors
    3. Reduced Testing Burden and OBD Requirements
    4. Hardship Relief
    5. Eligibility for the Flexibilities
    H. Compliance Provisions
    1. Exhaust Emission Test Procedures
    2. Reduced Test Burden
    3. Miscellaneous Provisions
    4. Manufacturer In-Use Verification Program (IUVP) Requirements
    V. Fuel Program
    A. Overview
    1. Background
    2. Summary of Final Tier 3 Fuel Program Standards
    B. Annual Average Sulfur Standard
    C. Per-Gallon Sulfur Caps
    1. Standards
    2. Requirements for Gasoline Additives
    D. Averaging, Banking, and Trading Program
    1. How will the ABT Program assist with compliance?
    2. ABT Modeling
    3. Eligibility
    4. Credit Generation and Use
    5. Credit Trading Provisions
    6. ABT Provisions for Small Refiners and Small Volume Refineries
    7. Deficit Carryforward
    E. Additional Program Flexibilities
    1. Regulatory Flexibility Provisions
    2. Provisions for Refiners Facing Hardship Situations
    F. Compliance Provisions
    1. Registration, Reporting, and Recordkeeping Requirements
    2. Sampling and Testing Requirements
    3. Small Refiner Compliance
    4. Small Volume Refinery Compliance
    5. Attest Engagements, Violations, and Penalties
    6. Special Fuel Provisions and Exemptions
    G. Standards for Oxygenates (Including Denatured Fuel Ethanol)
and Certified Ethanol Denaturants
    H. Standards for Fuel Used in Flexible Fueled Vehicles
    I. Sulfur Standards for Purity Butane and Purity Pentane Streams
Blended into Gasoline
    J. Standards for CNG and LPG
    K. Refinery Air Permitting Interactions
    1. Proposal
    2. Updated Assessment of Tier 3 Refinery Changes and Permitting
Implications
    3. Comments and Responses
    L. Refinery Feasibility
    1. Comments Received
    2. Is it feasible for refiners to comply with a 10 ppm average
sulfur standard?
    3. Can refiners meet the January 1, 2017 start date?
    M. Statutory Authority for Tier 3 Fuel Controls
    1. Section 211(c)(1)(A)
    2. Section 211(c)(1)(B)
    3. Section 211(c)(2)(B)
    4. Section 211(c)(2)(C)
VI. Technical Amendments and Regulatory Streamlining
    A. Fuel Program Amendments
    1. Fuels Program Regulatory Streamlining
    2. Performance-Based Measurement Systems (PBMS)
    3. Downstream Pentane Blending

    4. Acceptance of Top Tier Deposit Control Test Data
    5. Potential Broader Regulatory Streamlining Through Program
Restructuring
    B. Engine, Vehicle and Equipment Programs Amendments
    1. Fuel Economy Labeling
    2. Removing Obsolete Regulatory Text
    3. Motorcycle Driving Schedules
    4. Updating Reference Procedures
VII. What are the cost impacts of the rule?
    A. Estimated Costs of the Vehicle Standards
    1. What changes have been made to vehicle program costs since
proposal?
    2. Summary of Vehicle Program Costs
    B. Estimated Costs of the Fuel Program
    1. Overview
    2. Methodology
    3. Fuel Program Costs
    4. Other Cost Estimates
    C. Summary of Program Costs
VIII. What are the estimated benefits of the rule?
    A. Overview
    B. Quantified Human Health Impacts
    C. Monetized Benefits
    D. What are the limitations of the benefits analysis?
    E. Illustrative Analysis of Estimated Monetized Impacts
Associated With the Rule in 2018
    IX. Alternatives Analysis
    A. Vehicle Emission Standards
    1. Shorter NMOG+NOX Standard Phase-in
    2. NMOG+NOX Standards Phase-in and Early Tier 3
Credits
    3. NMOG+NOX Standards
    4. PM Standards
    5. Higher Ethanol Content of Emissions Test Fuel
    B. Fuel Sulfur Standards
    1. Annual Average Sulfur Standard
    2. Refinery Gate Sulfur Cap
    C. Program Start Date
X. Economic Impact Analysis
    A. Introduction
    B. Vehicle Sales Impacts
    C. Impacts on Petroleum Refinery Sector Production
    D. Employment Impacts
    1. Employment Impacts in the Auto Sector
    2. Refinery Employment Impacts
XI. Public Participation
XII. Statutory 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
    C. Regulatory Flexibility Act
    1. Overview
    2. Background
    3. Reason for Today's Rule
    4. Legal Basis for Agency Action
    5. Summary of Potentially Affected Small Entities
    6. Reporting, Recordkeeping, and Compliance
    7. Related Federal Rules
    8. Steps Taken To Minimize the Economic Impact on Small Entities
    D. Unfunded Mandates Reform Act
    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
    J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
    K. Congressional Review Act
XIII. Statutory Provisions and Legal Authority

I. Executive Summary and Program Overview

A. Introduction

    In this action, EPA is finalizing a major program designed to
reduce air pollution from passenger cars and trucks. This program
includes new standards for both vehicle emissions and the sulfur
content of gasoline, considering the vehicle and its fuel as an
integrated system. We refer to this program as the ``Tier 3'' vehicle
and fuel standards.
    This rule is part of a comprehensive approach to address the
impacts of motor vehicles on air quality and public health. Over 149
million Americans are currently experiencing unhealthy levels of air
pollution, which are linked with respiratory and cardiovascular
problems and other adverse health impacts that lead to increased
medication use, hospital admissions, emergency department visits, and
premature mortality.\1\ Motor vehicles are a particularly important
source of exposure to air pollution, especially in urban areas. By
2018, we project that in many areas that are not attaining health-based
ambient air quality standards (i.e., ``nonattainment areas''),
passenger cars and light trucks will contribute 10-25 percent of total
nitrogen oxides (NOX) emissions, 15-30 percent of total
volatile organic compound (VOC) emissions, and 5-10 percent of total
direct particulate matter (PM2.5) emissions.\2\ These
compounds form ozone, PM, and other air pollutants, whose health and
environmental effects are described in more detail in Section II. Cars
and light trucks also continue to be a significant contributor to air
pollution directly near roads, with gasoline vehicles accounting for
more than 50 percent of near-road concentrations of some criteria and
toxic pollutants.\3\ More than 50 million people live, work, or go to
school in close proximity to high-traffic roadways, and the average
American spends more than one hour traveling along roads each
day.4 5 Over 80 percent of daily trips use personal
vehicles.\6\
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    \1\ The 149 million represents people living in O3,
PM2.5, PM10, and SO2 nonattainment
areas. Data come from Summary Nonattainment Area Population Exposure
Report, current as of December 5, 2013 at: http://www.epa.gov/oar/oaqps/greenbk/popexp.html and contained in Docket EPA-HQ-OAR-2011-
0135.
    \2\ Mobile source contributions derived from inventories
developed for this rule. For more information on these inventories
see the Emissions Inventory Technical Support Document (TSD) for the
final Tier 3 Rule, Docket ID No. EPA-HQ-OAR-2011-0135.
    \3\ For example, see Fujita, E.M; Campbell, D.E.; Zielinska, B.;
Arnott, W.P.; Chow, J.C. (2011) Concentrations of Air Toxics in
Motor Vehicle-Dominated Environments. Health Effects Institute
Research Report 156. Available at http://www.healtheffects.org.
    \4\ U.S. Census Bureau (2011). Current Housing Reports, Series
H150/09, American Housing Survey for the United States: 2009. U.S.
Government Printing Office, Washington, DC. Available at http://www.census.gov/hhes/www/housing/ahs/ahs09/ahs09.html. (Note that
this survey includes estimates of homes within 300 feet of highways
with four or more lanes, railroads, and airports.)
    \5\ Drago, R. (2011). Secondary activities in the 2006 American
Time Use Survey. U.S. Bureau of Labor Statistics Working Paper 446.
Available at http://www.bls.gov.
    \6\ Santos, A.; McGuckin, N, Yukiko Nakamoto, H.; Gray, D.;
Liss, S. (2011) Summary of Travel Trends: 2009 National Household
Travel Survey. Federal Highway Administration report no FHWA-PL-11-
022. Available at http://nhts.ornl.gov/publications.shtml.
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    The standards set forth in this rule will significantly reduce
levels of multiple air pollutants (such as ambient levels of ozone, PM,
nitrogen dioxide (NO2), and mobile source air toxics
(MSATs)) across the country, with immediate benefits from the gasoline
sulfur control standards starting in 2017. These reductions will help
state and local agencies in their effort to attain and maintain health-
based National Ambient Air Quality Standards (NAAQS). Few other
national strategies exist that will deliver the same magnitude of
multi-pollutant reductions and associated public health protection that
is projected to result from the Tier 3 standards. Without this action
to reduce nationwide motor vehicle emissions, areas would have to adopt
other, less cost-effective measures to reduce emissions from other
sources under their state or local authority. In the absence of
additional controls, certain areas would continue to have ambient ozone
concentrations exceeding the NAAQS in the future. See Section III.C for
more details.
    The Clean Air Act authorizes EPA to establish emissions standards
for motor vehicles to address air pollution that may reasonably be
anticipated to endanger public health or welfare

(section 202). EPA also has authority to establish fuel controls to
address such air pollution (section 211). These statutory authorities
are described in Section II.A.
    The vehicle and gasoline sulfur standards we are finalizing
represent a ``systems approach'' to reducing vehicle exhaust and
evaporative emissions by addressing the vehicle and fuel as a system.
The systems approach enables emission reductions that are both
technologically feasible and cost-effective beyond what would be
possible looking at vehicle and fuel standards in isolation. We first
applied such an approach with our Tier 2 vehicle/gasoline sulfur
standards (finalized in 2000).\7\ We believe that a similar approach
for the Tier 3 standards is a cost-effective way to achieve substantial
additional emissions reductions.
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    \7\ 65 FR 6698 (February 10, 2000).
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    The Tier 3 standards include new light- and heavy-duty vehicle
emission standards for exhaust emissions of VOC (specifically, non-
methane organic gases, or NMOG), NOX, and PM, as well as new
evaporative emissions standards. The fully phased-in standards for
light-duty vehicle, light-duty truck, and medium-duty passenger vehicle
tailpipe emissions are an 80 percent reduction in fleet average
NMOG+NOX compared to current standards, and a 70 percent
reduction in per-vehicle PM standards. The fully phased-in Tier 3
heavy-duty vehicle tailpipe emissions standards for NMOG+NOX
and PM are on the order of 60 percent lower than current standards.
Finally, the fully phased-in evaporative emissions standards represent
a 50 percent reduction from current standards.
    The vehicle emission standards, combined with the reduction of
gasoline sulfur content from the current 30 parts per million (ppm)
average down to a 10 ppm average, will result in dramatic emissions
reductions for NOX, VOC, direct PM2.5, carbon
monoxide (CO) and air toxics. For example, in 2030, when Tier 3
vehicles will make up the majority of the fleet as well as vehicle
miles traveled, NOX and VOC emissions from on-highway
vehicles will be reduced by about 21 percent, and CO emissions will be
reduced by about 24 percent. National emissions of many air toxics from
on-highway vehicles will also be reduced by 10 to nearly 30 percent.
Reductions will continue beyond 2030 as more of the fleet is composed
of vehicles meeting the fully phased-in Tier 3 standards. For example,
the Tier 3 program will reduce on-highway emissions of NOX
and VOC nearly 31 percent by 2050, when vehicles meeting the fully
phased-in Tier 3 standards will comprise almost the entire fleet.
    Gasoline vehicles depend to a great degree on catalytic converters
to reduce levels of pollutants in their exhaust, including NMOG and
NOX, as well as PM (specifically, the volatile hydrocarbon
fraction), CO, and most air toxics. The catalytic converters become
significantly less efficient when exposed to sulfur. The Tier 2
rulemaking required refiners to take steps to reduce sulfur levels in
gasoline by approximately 90 percent, to an average of 30 ppm. As
discussed in Section IV.A.6, subsequent research provides a compelling
case that even this level of sulfur not only degrades the emission
performance of vehicles on the road today, but also inhibits necessary
further reductions in vehicle emissions performance to reach the Tier 3
standards. Thus, the 10 ppm average sulfur standard for Tier 3 is
significant in two ways: it enables vehicles designed to the Tier 3
tailpipe exhaust standards to meet these standards in-use for the
duration of their useful life, and it facilitates immediate emission
reductions from all the vehicles on the road at the time the fuel
sulfur controls are implemented. EPA is not the first regulatory agency
to recognize the need for lower-sulfur gasoline. Agencies in Europe and
Japan have already imposed gasoline sulfur caps of 10 ppm, and the
State of California is already averaging 10 ppm sulfur with a per
gallon cap of 20 ppm. Other states are preempted by the Clean Air Act
from adopting new fuel programs to meet air quality objectives.
Consequently, they could not receive the air quality benefits of lower
sulfur gasoline without federal action.
    This action is one aspect of a comprehensive national program
regulating emissions from motor vehicles. EPA's final rule for reducing
greenhouse gas (GHG) emissions from light-duty (LD) vehicles starting
with model year (MY) 2017 (referred to here as the ``2017 LD GHG''
standards) is another aspect of this comprehensive program.\8\ The Tier
3 program addresses interactions with the 2017 LD GHG rule in a manner
that aligns implementation of the two actions, to achieve significant
criteria pollutant and GHG emissions reductions while providing
regulatory certainty and compliance efficiency. As vehicle
manufacturers introduce new vehicle platforms for compliance with the
GHG standards, they will be able to design them for compliance with the
Tier 3 standards at the same time. The Tier 3 standards are also
closely coordinated with California's Low Emission Vehicle (LEV) III
program to create a vehicle emissions program that will allow
automakers to sell the same vehicles in all 50 states. (In December
2012 EPA approved a waiver of Clean Air Act preemption for the
California Air Resources Board's (CARB's) LEV III program with
compliance beginning in 2015. Twelve states adopted the LEV III program
under Section 177 of the Clean Air Act.\9\) We have worked closely with
individual vehicle manufacturers and their trade associations, who have
emphasized the importance of a harmonized national program. Together,
the Tier 3, 2017 LD GHG, and LEV III standards will provide significant
reductions in GHGs, criteria pollutants and air toxics from motor
vehicles while streamlining programs and enabling manufacturers to
design a single vehicle for nationwide sales, thus reducing their costs
of compliance. In this way, the Tier 3 program responds to the May 21,
2010 Presidential Memorandum that requested that EPA develop a
comprehensive approach toward regulating motor vehicles, including
consideration of non-GHG emissions standards.\10\
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    \8\ EPA's GHG standards are part of a joint National Program
with the National Highway Traffic Safety Administration, which also
set coordinated standards for Corporate Average Fuel Economy (CAFE).
77 FR 62623 (October 15, 2012).
    \9\ These states include Connecticut, Delaware, Maryland, Maine,
Massachusetts, New Jersey, New York, Oregon, Pennsylvania, Rhode
Island, Washington, and Vermont.
    \10\ The Presidential Memorandum is found at: http://www.whitehouse.gov/the-press-office/presidential-memorandum-regarding-fuel-efficiency-standards.
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    As part of the systems approach to this program, we have considered
the types of fuels on which vehicles will be operating in the future.
In particular, the renewable fuels mandate that was revised by the
Energy Independence and Security Act (EISA) and is being implemented
through the Renewable Fuel Standards program (RFS2) \11\ is resulting
in the use of significant amounts of ethanol-blended gasoline. We are
updating the specifications of the emissions test fuel with which
vehicles demonstrate compliance with emissions standards, in order to
better reflect the ethanol content and other properties of gasoline
that is in use today and is expected in future years.
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    \11\ 75 FR 14670 (March 26, 2010).
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    Section I provides an overview of the vehicle and fuel standards we
are finalizing as well as the impacts of the standards. The public
health issues and statutory requirements that have prompted this action
are described in Section II, and our discussion of how

the Tier 3 standards will reduce emissions and air pollution is
presented in Section III. Details of the standards and how they will be
implemented can be found in Sections IV through VI. Sections VII
through X contain our discussion of the standards' technological
feasibility and costs, benefits, and economic impacts. Sections XI
through XIII address public participation, statutory and executive
orders, and statutory provisions and legal authority under the Clean
Air Act covered in this rulemaking.
    This final rule is based on extensive public input received in
response to EPA's Tier 3 proposal. The proposal was signed and posted
on the EPA Web site on March 29, 2013, and published in the Federal
Register on May 21, 2013. EPA held two public hearings in Philadelphia
and Chicago in April 2013. In response to stakeholder requests, EPA
extended the public comment period to July 1, 2013. We received more
than 200,000 public comments. A broad range of stakeholders provided
comments, including state and local governments, auto manufacturers,
emissions control suppliers, refiners, fuel distributors and others in
the petroleum industry, renewable fuels providers, environmental
organizations, consumer groups, labor groups, private citizens, and
others. Some of the issues raised in comments included lead time and
the program's start date, the vehicle manufacturers' support for a 50-
state program harmonized with California, the need for and degree of
gasoline sulfur control (including the level of the sulfur cap), the
ethanol content of vehicle certification test fuel, and various details
on the flexibilities and other program design features of both the
vehicle and fuels standards.

B. Overview of the Tier 3 Program

    In the 14 years since EPA established the Tier 2 Vehicle Program,
manufacturers of light-duty vehicles and automotive technology
suppliers have continued to develop a wide range of improved
technologies capable of reducing vehicle emissions. The California LEV
II program has been instrumental in the continuous technology
improvements by requiring year after year reductions in fleet average
hydrocarbon levels, in addition to requiring the introduction of
advanced exhaust and evaporative emission controls in partial zero
emission vehicles (PZEVs). This technological progress has made it
possible for manufacturers to achieve emission reductions well beyond
the requirements of the Tier 2 program if gasoline sulfur levels are
lowered further.
    As a result, in conjunction with lower gasoline sulfur standards,
we are establishing new Tier 3 standards for exhaust emissions of NMOG,
NOX, and PM, as well as for evaporative hydrocarbon
emissions. These vehicle emissions standards will phase in beginning
with MY 2017. The structure of the Tier 3 standards is very similar to
that of the existing Tier 2 program. As with the Tier 2 program, the
standards will apply to all light-duty vehicles (LDVs, or passenger
cars), light-duty trucks (LDT1s, LDT2s, LDT3s, and LDT4s) and Medium-
Duty Passenger Vehicles (MDPVs). We also are establishing separate but
closely related standards for heavy-duty vehicles up to 14,000 lbs
Gross Vehicle Weight Rating (GVWR).\12\ We have concluded that the
vehicle emissions standards, in conjunction with the reductions in fuel
sulfur also required by this action, are feasible across the fleet in
the timeframe provided.
---------------------------------------------------------------------------

    \12\ These heavy-duty vehicles were not included in the Tier 2
program but were subject to standards in a subsequent rule covering
the heavy-duty sector (66 FR 5002, January 18, 2001).
---------------------------------------------------------------------------

    Auto manufacturers have stressed the importance of being able to
design, produce, and sell a single fleet of vehicles in all 50 states
that complies with both the Tier 3 and California LEV III programs, as
well as the greenhouse gas (GHG)/Corporate Average Fuel Economy (CAFE)
programs in the same timeframe. To that end, we worked closely with the
California Air Resources Board and vehicle manufacturers to align the
two programs as closely as possible. This consistency among the federal
and California programs means that manufacturers do not need to design
unique versions of vehicles with different emission control hardware
and calibrations for different geographic areas. This allows
manufacturers to avoid the additional costs of parallel design,
development, calibration, and manufacturing. We also have designed the
Tier 3 program to be implemented in the same timeframe as the GHG
emissions and fuel economy standards for model years 2017-2025. We
expect that in response to these programs, manufacturers will be
developing entirely new powertrains for most of their vehicles. Because
the Tier 3 standards will phase in over the same timeframe,
manufacturers are in a better position to simultaneously respond to all
of these requirements.
    Overall, the final Tier 3 program is very similar to the program we
proposed. As discussed below and throughout this preamble, the program
phases in over several years--with the primary vehicle emission
standards starting in Model Year (MY) 2017 (2018 for heavier vehicles)
and the gasoline sulfur control provisions beginning in 2017.
    As discussed above, we received a large number and wide range of
comments on the proposed rule. Several comments raise particularly
significant issues concerning some fundamental components of the Tier 3
program, including when the vehicle-related and fuel-related
requirements begin. We briefly discuss these key issues in this
section, and in more detail later in this preamble. The Summary and
Analysis of Comments document provides our responses to the comments we
received; it is located in the docket for this rulemaking and also on
EPA's Web site at www.epa.gov/otaq/tier3.htm.
1. Major Public Comments and Key Changes From the Proposal
a. Start Date and Lead Time Issues
(1) Gasoline Sulfur Control Program
    Many stakeholders commented on the proposed 2017 start date of the
Tier 3 program, with state and NGO organizations supporting finalizing
the standards as proposed. Conversely, refiners, importers, and others
in the fuel industry commented that they believed the proposed start
date would not provide a sufficient amount of lead time to meet the
requirements of the Tier 3 program, and that EPA has historically
provided at least four years of lead time in previous fuels
rulemakings. These commenters noted that five years of lead time is
needed to allow for necessary refinery changes to be made during a
refinery's normal turnaround/shutdown schedule (these occur every four
years, on average) and to allow adequate time for the permitting
process. These commenters also stated that, given the proposed
flexibility provisions for vehicles, that a 2017 fuel program start
date was not truly needed to enable the vehicle technology. Further,
these commenters stated that they believed insufficient lead time would
drive up the costs for regulated entities as they would need to do
unscheduled shutdowns to install and/or revamp equipment to meet the
proposed standards. Lastly, they stated that the uncertainty regarding
the potential availability of credits would make meeting a 2017 start
date more challenging.
    As discussed in greater detail in Section V below, we are
finalizing the proposed start date of January 1, 2017. We understand
refiners' concerns,

including their concerns over the necessary capital investments and
potential off-cycle turnarounds/shutdowns to make refinery
modifications for Tier 3. In light of these concerns, we are finalizing
additional flexibilities beyond those already in the proposal and we
are confident that the program being finalized today addresses these
concerns. Considering all the flexibilities offered to regulated
parties, there is, in effect, nearly 6 years of time to comply provided
for those refineries that may need it. As discussed in Section V.D, we
are finalizing a credit averaging, banking, and trading (ABT) program
that will allow for a smooth transition from the Tier 2 to Tier 3 ABT
programs (including provisions for early credit generation beginning in
2014). These early credit provisions, coupled with the ability to carry
over credits from Tier 2 into Tier 3 (an additional flexibility being
finalized today that was not part of the proposal), will allow for
early actions to reduce sulfur levels by some refineries to be used to
delay the need for actions at other refineries until 2020. This
structure of the ABT program allows refiners and importers the
flexibility to choose the most economical compliance strategy--
investment in technology, use of credits, or both--for meeting the Tier
3 average gasoline sulfur standard. In addition, approved small
refiners and small volume refineries are given an additional three
years from the January 1, 2017, Tier 3 program start date to comply
(January 1, 2020).
    We proposed that the Tier 2 ABT program would not only be separate
from the Tier 3 ABT program, but that it would also end at the start of
the Tier 3 program in 2017. The implications of this meant that any
Tier 2 credits generated after 2012 would run the risk of expiring
before the end of their full five-year life if they were not used
before January 1, 2017. Commenters requested that EPA consider allowing
such Tier 2 ``banked'' credits to receive their full five-year life.
This would eliminate any incentive refiners may have to use these
credits prior to the end of the Tier 2 program to raise their in-use
sulfur levels. The ABT program that we are finalizing today enables a
seamless transition from Tier 2 to Tier 3, including an allowance for
Tier 2 banked credits to be used for their full five-year life or
through December 31, 2019, whichever is earlier. Not only does this
provision effectively provide more lead time and flexibility for
refiners and importers, but we believe these banked credits will help
to provide certainty of the availability of credits for refiners and
importers who may want to rely on them for compliance.
    Finally, as discussed in Section V.E.2, we are also finalizing
hardship provisions that allow refiners to petition for delayed
compliance, on a case-by-case basis, for situations of extreme hardship
or extreme unforeseen circumstances. These provisions, similar to those
implemented in past fuel rulemakings, provide a safety valve should all
the other flexibilities provided prove insufficient. As part of these
hardship provisions, we are finalizing the ability for refiners to
carry a deficit for up to 3 years, providing them with yet additional
flexibility during the transition to Tier 3 should it prove necessary.
(2) Vehicle Emission Control Program
    There were no major concerns raised for the proposed MY 2017 start
date for lighter light-duty vehicles, although commenters from the auto
manufacturing industry raised concerns about the lead time we proposed
for heavier light-duty vehicles. Specifically, commenters pointed to
Clean Air Act section 202(a)(3)(C) that, for vehicles over 6,000 lbs
GVWR, requires that EPA emission standards provide at least four years
of lead time and three years of regulatory stability.
    In light of this statutory requirement, in addition to the primary
declining fleet average standards starting in MY 2018 for heavier
vehicles, EPA proposed an alternative phase-in schedule for any
manufacturer that prefers a longer lead time and annual stability for
these vehicles in lieu of the declining fleet average standards option.
The commenters stated that the proposed alternative pathway would be
too difficult to take advantage of in comparison to the primary program
and thereby failed to comply with the Clean Air Act.
    In considering these comments, EPA also considered that during the
development of the Tier 3 program and in their comments, the same auto
industry commenters consistently urged EPA to design the Tier 3 program
to harmonize with the California LEV III standards as closely and as
early as possible. As discussed in detail below in Section IV.A,
extensive data that EPA has generated or received continue to support
the conclusion that the primary fleet-average standards provide a
compliance path that is feasible across the industry and that closely
harmonizes with LEV III. EPA believes that we have reasonably resolved
these somewhat competing concerns--early harmonization vs. additional
lead time--by finalizing the primary declining fleet average standards
as proposed while also finalizing revised alternative phase-in
compliance schedules (see Section IV.A.2.c). In response to the
comments on this topic, we have revised the alternative phase-in
schedules to reduce their associated burden for manufacturers, while
still maintaining environmental benefits that are equivalent to the
primary program. We also include provisions in the percent-of-sales
phase-in alternatives that allow manufacturers to exclude vehicle
models that begin their 2019 model year production early in 2018, in
order to provide four years of lead time.
b. Emissions Test Fuel
    In-use gasoline has changed considerably since EPA last revised
specifications for the test gasoline used in emissions testing of
light- and heavy-duty vehicles. Perhaps most importantly, gasoline
containing 10 percent ethanol by volume (E10) has replaced non-
oxygenated gasoline (E0) across the country. As a result, we are
updating federal emissions test fuel specifications to better match in-
use fuel.
    In the NPRM, EPA proposed that the specified gasoline for emissions
testing be changed from E0 to E15 as a forward-looking approach. Since
then, several factors have led EPA to reconsider that approach,
including minimal proliferation on a national scale of stations
offering E15 and the complexities that E15 would introduce for long-
term harmonization with California's use of E10 in their LEVIII
program. We received comments from a broad set of stakeholders
including the auto and oil industries, states, and NGOs with a general
consensus that E15 would not be appropriate as the official test fuel
at this time. Ethanol industry commenters supported E15 certification
fuel, but provided no timeline by which this blend level would be
representative of in-use fuel. In light of the comments received and
EPA's assessment of the current and projected levels of ethanol in
gasoline in use, we are finalizing E10 as the new emissions test fuel.
    In deciding to finalize E10 test fuel, EPA considered whether to
change the volatility of the test fuel, typically expressed as pounds
per square inch (psi) Reid Vapor Pressure (RVP). As discussed in detail
in Section IV.F, after considering technical and policy implications as
well as stakeholder comments, we have concluded that the most
appropriate approach is to maintain an RVP of 9 psi for the E10
emissions test fuel at this time. EPA considered raising test fuel RVP
to 10

psi, but decided to leave it unchanged at 9 psi based on what would
have been the associated increase in stringency of the Tier 3
evaporative standard with 10 psi and the loss of regulatory harmony on
evaporative emissions with California's LEV III program.
    As a result, after reassessing market trends and considering
comments, EPA concludes that the most appropriate approach is to
finalize an ethanol content of 10 percent and an RVP of 9 psi for
emissions test gasoline. We will continue to monitor ethanol trends in
the gasoline market, as discussed later in this preamble.
c. Gasoline Sulfur Caps
    As described in more detail in Section V.C. we proposed two options
for the Tier 3 per-gallon sulfur caps--maintaining the Tier 2 refinery
gate sulfur cap of 80 ppm (with a 95 ppm downstream sulfur cap), and
lowering to a 50 ppm refinery gate sulfur cap beginning January 1, 2020
(with a 65 ppm downstream cap). We received comments supporting lower
per-gallon caps which noted potential environmental benefits, greater
certainty that vehicles would see lower and more uniform gasoline
sulfur levels, and the ability to enable new vehicle technologies
requiring very low sulfur levels. Conversely, comments received in
support of maintaining the Tier 2 per-gallon caps cited concerns on
cost, flexibility for turnarounds/unplanned shutdowns (due to refinery
fires, natural disasters, etc.), and gasoline supply and/or price
impacts.
    Analysis performed since the time of the proposal found that a
lower refinery gate cap would likely result in higher costs to the
fuels industry and a decreased ability to handle off-spec product
(potentially impacting gasoline supply and pricing), without any
significant increase in the nationwide emissions reductions provided by
the Tier 3 program. Thus, in today's action we are retaining the Tier 2
per-gallon sulfur caps. The 80 ppm refinery gate cap will provide
refiners needed flexibility in allowing for naturally-occurring fuel
batch variability, as well as more certainty that they will be able to
continue producing and distributing gasoline during turnarounds/upsets
to avoid a total shutdown. It will also provide more certainty for
transmix processors, additive manufacturers, and other downstream
parties in producing gasoline.
    However, we do understand commenters' concerns that retaining the
Tier 2 sulfur caps might create regional differences in the benefits of
the Tier 3 program. Therefore we will continue to monitor in-use sulfur
levels and their impact on vehicle emissions to ascertain whether a
future reduction in the per-gallon cap may be necessary.
d. Effect of Gasoline Sulfur on Tier 3 Vehicle Emissions
    The need for and level of gasoline sulfur control was a key issue
raised in public comments. The petroleum industry raised concerns that
there was insufficient basis for the proposed 10 ppm average sulfur
level, while auto manufacturers and emissions control equipment
manufacturers stressed that the feasibility of the Tier 3 vehicle
standards was dependent on near-zero gasoline sulfur levels. This issue
is discussed in detail below in Section IV.A.6. In sum, EPA believes
that the range of studies conducted by EPA and others in recent years,
along with the comments submitted by the auto industry and emissions
control manufacturers during the comment period and more recently,
strongly reinforce our conclusion that the impact of gasoline sulfur
poisoning on exhaust catalyst performance is significant.
    Sulfur is a well-known catalyst poison. The nature of sulfur's
interactions with active catalytic materials is complex and varies with
catalyst composition, exhaust gas composition, and exhaust temperature.
Thus, even if a manufacturer were able to certify a new vehicle to the
new stringent standards, the manufacturer's ability to maintain the
emission performance of that vehicle in-use is greatly jeopardized if
the vehicle is being operated on gasoline sulfur levels greater than 10
ppm. In fact, due to the variation in actual vehicle operation, any
amount of gasoline sulfur will deteriorate catalyst efficiency. Vehicle
manufacturers and suppliers, both individually and through their trade
associations, stressed the need for gasoline sulfur to be reduced to
near zero levels in order for them to meet the proposed standards.
However, we believe that a 10 ppm average sulfur level is sufficiently
low to enable compliance with the Tier 3 vehicle standards, and as
described below and in Section V, reducing sulfur levels further would
cause sulfur control costs to quickly escalate.
    Taken together, this information provides a compelling argument
that the fleetwide Tier 3 vehicle standards are achievable only with a
reduction of gasoline sulfur content from the current 30 ppm average
down to a 10 ppm average.
e. SFTP (US06) PM Standard for Light-Duty Vehicles
    The final Tier 3 vehicle standards are largely unchanged from their
proposed levels. One change from the proposal is the PM emissions
standards as measured on the US06 test cycle. The US06 cycle is part of
the composite Supplemental Federal Test Procedure (SFTP) and simulates
aggressive driving. The US06 PM standards are part of the suite of Tier
3 tailpipe standards that limit emissions under a wide range of common
vehicle driving conditions. Newer emissions test data presented in the
NPRM, as well as more recent additional test data submitted in public
comments, show that a numerically lower US06 PM standard is feasible
and appropriately reflects the actual emissions performance achieved by
many vehicles in the fleet today while preventing increased emissions
in the future.
    Taken together, the test results clearly show that most current
light-duty vehicles--regardless of engine technology, emission control
strategy, or vehicle size--are performing at much lower US06 emission
levels than previously documented. Based on these newer data, we
believe that it is appropriate to finalize a numerically lower US06 PM
emission standard for LDVs, LDTs, and MDPVs, and to set a single
standard for both lighter and heavier vehicles in this vehicle segment.
In general, the final US06 PM standard for these vehicles begins to
phase in at a level of 10 mg/mi in MYs 2017 and 2018, stepping down to
a level of 6 mg/mi in MY2019. See Section IV.A.4.b for additional
discussion of the US06 standards and how they will phase in.
2. Key Components of the Tier 3 Program
a. Tailpipe Standards for Light-Duty Vehicle, Light-Duty Truck, and
Medium-Duty Passenger Vehicle Tailpipe Emissions
    We are establishing a comprehensive program that includes new
fleet-average standards for the sum of NMOG and NOX tailpipe
emissions (presented as NMOG+NOX) as well as new per-vehicle
standards for PM.\13\ These standards, when applied in conjunction with
reduced gasoline sulfur content, will result in very significant
improvements in vehicle emissions from the levels of the Tier 2
program. For these pollutants, the standards are measured on test
procedures that represent a range of

vehicle operation, including the Federal Test Procedure (or FTP,
simulating typical driving) and the Supplemental Federal Test Procedure
(or SFTP, a composite test simulating higher ambient temperatures,
higher vehicle speeds, and quicker accelerations). In addition to the
standards, we are extending the regulatory useful life period during
which the standards apply (see Section IV.A.7.b below) and making test
fuel more representative of expected real-world fuel (see Section
I.B.2.e below). The final standards are in most cases identical to
those of California's LEVIII program, which provides the 50-state
harmonization strongly supported by the auto industry.
---------------------------------------------------------------------------

    \13\ A discussion of the reasons for combining NMOG and
NOX for this purpose is in Section IV.A.3.a below.
---------------------------------------------------------------------------

    As proposed, the new Tier 3 FTP and SFTP NMOG+NOX
standards are fleet-average standards, meaning that a manufacturer
calculates the average emissions of the vehicles it sells in each model
year and compares that average to the applicable standard for that
model year. The manufacturer certifies each of its vehicles to a per-
vehicle ``bin'' standard (see Section IV.A.2) and sales-weights these
values to calculate its fleet-average NMOG+NOX emissions for
each model year. Table I-1 summarizes the fleet average standards for
NMOG+NOX evaluated over the FTP. The standards for light-
duty vehicles begin in MY 2017 at a level representing a 46 percent
reduction from the Tier 2 requirements. For the light-duty fleet over
6000 lbs GVWR, and MDPVs, the standards apply beginning in MY 2018. As
shown, these fleet-average standards decline during the first several
years of the program, becoming increasingly stringent until ultimately
reaching an 81 percent reduction when the transition is complete. The
FTP NMOG+NOX program includes two separate sets of declining
fleet-average standards, with LDVs and small light trucks in one
grouping and heavier light trucks and MDPVs in a second grouping, that
converge at 30 milligrams per mile (mg/mi) in MY 2025 and later. As
mentioned above, we are also providing alternative percent phase-in
schedules for this and the other light-duty standards.

                                        Table I-1--Tier 3 LDV, LDT, and MDPV Fleet Average FTP NMOG+NOX Standards
                                                                         [mg/mi]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Model year
                                                      --------------------------------------------------------------------------------------------------
                                                                                2025 and
                                                        2017 \a\     2018       2019       2020       2021       2022       2023       2024      later
--------------------------------------------------------------------------------------------------------------------------------------------------------
LDV/LDT1 \b\.........................................         86         79         72         65         58         51         44         37         30
LDT2,3,4 and MDPV....................................        101         92         83         74         65         56         47         38         30
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ For LDV and LDTs above 6000 lbs GVWR and MDPVs, the fleet average standards apply beginning in MY 2018.
\b\ These standards apply for a 150,000 mile useful life. Manufacturers can choose to certify some or all of their LDVs and LDT1s to a useful life of
  120,000 miles. If a vehicle model is certified to the shorter useful life, a proportionally lower numerical fleet-average standard applies, calculated
  by multiplying the respective 150,000 mile standard by 0.85 and rounding to the nearest mg. See Section IV.A.7.c.

    Similarly, as proposed, the NMOG+NOX standards measured
over the SFTP are fleet-average standards, declining from MY 2017 until
MY 2025, as shown in Table I-2. In this case, the same standards apply
to both lighter and heavier vehicles in the light-duty fleet. In MY
2025, the SFTP NMOG+NOX standard reaches its final fleet
average level of 50 mg/mi.

                                       Table I-2--Tier 3 LDV, LDT, and MDPV Fleet Average SFTP NMOG+NOX Standards
                                                                         [mg/mi]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Model year
                                             -----------------------------------------------------------------------------------------------------------
                                                                                2025 and
                                               2017 \a\      2018        2019        2020        2021        2022        2023        2024        later
--------------------------------------------------------------------------------------------------------------------------------------------------------
NMOG + NOX..................................        103          97          90          83          77          70          63          57          50
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ For LDVs and LDTs above 6000 lbs GVWR and MDPVs, the fleet average standards apply beginning in MY 2018.

    As proposed, manufacturers can also earn credits if their fleet
average NMOG+NOX performance is better than the applicable
standard in any model year. Credits that have been previously banked or
obtained from other manufacturers can be used, or credits can be traded
to other manufacturers. Manufacturers would also be allowed to carry
forward deficits in their credit balance. (See Sections IV.A.7.a and
IV.A.7.m).
    We are also establishing PM standards as part of the Tier 3
program, for both the FTP and US06 cycles (as described above, US06 is
a component of the SFTP test). Research has demonstrated that the level
of PM from gasoline light-duty vehicles is more significant than
previously thought.\14\ Although many vehicles today are performing at
or near the levels of the new standards, the data indicate that
improvements, especially in high-load fuel control and in the
durability of engine components, are possible.
---------------------------------------------------------------------------

    \14\ Nam, E.; Fulper, C.; Warila, J.; Somers, J.; Michaels, H.;
Baldauf, R.; Rykowski, R.; and Scarbro, C. (2008). Analysis of
Particulate Matter Emissions from Light-Duty Gasoline Vehicles in
Kansas City, EPA420-R-08-010. Assessment and Standards Division
Office of Transportation and Air Quality U.S. Environmental
Protection Agency Ann Arbor, MI, April 2008.
---------------------------------------------------------------------------

    Under typical driving, as simulated by the FTP, the PM emissions of
most current-technology gasoline vehicles are fairly low at
certification and in use, well below the Tier 2 PM standards. At the
same time we see considerable variation in PM emissions among vehicles
of various makes, models, and designs. As a result, as proposed, we are
setting the new FTP PM standard at a level that will ensure that all
new vehicles perform at the level already being achieved by well-
designed Tier 2 vehicles. The PM standards apply to each vehicle
separately (i.e., not as a fleet average). Also, in contrast to the
declining NMOG+NOX standards, the

PM standard on the FTP for certification testing is 3 mg/mi for all
vehicles and for all model years. As for the NMOG+NOX
standards, for vehicles over 6000 lbs GVWR, the FTP PM standard applies
beginning in MY 2018. Manufacturers can phase in their vehicle models
as a percent of U.S. sales through MY 2022. Most vehicles are already
performing at this stringent PM level, and the primary intent of the
standard is to bring all light-duty vehicles to the typical level of PM
performance being demonstrated by many of today's vehicles.
    As proposed, the Tier 3 program also includes a temporary in-use
FTP PM standard of 6 mg/mi for the testing of in-use vehicles that
applies during the percent phase-in period only. This in-use standard
will address the in-use variability and durability uncertainties that
accompany the introduction of new technologies. Table I-3 presents the
FTP certification and in-use PM standards and the phase-in percentages.

                                 Table I-3--Phase-In for Tier 3 FTP PM Standards
----------------------------------------------------------------------------------------------------------------
                                                                                2022 and
                                                 2017 \a\     2018       2019       2020       2021      later
----------------------------------------------------------------------------------------------------------------
Phase-In (percent of U.S. sales)..............     \b\ 20         20         40         70        100        100
Certification Standard (mg/mi)................          3          3          3          3          3          3
In-Use Standard (mg/mi).......................          6          6          6          6          6          3
----------------------------------------------------------------------------------------------------------------
\a\ For LDVs and LDTs above 6000 lbs GVWR and MDPVs, the FTP PM standards apply beginning in MY 2018.
\b\ Manufacturers comply in MY 2017 with 20 percent of their LDV and LDT fleet under 6,000 lbs GVWR, or
  alternatively with 10 percent of their total LDV, LDT, and MDPV fleet.

    Finally, as discussed in Section I.B.1.e above, the Tier 3 program
includes PM standards evaluated over the US06 driving cycle (the US06
is one part of the SFTP procedure) of 10 mg/mi through MY 2018 and of 6
mg/mi for 2019 and later model years, for light-duty vehicles. As in
the case of the FTP PM standards, the intent of the US06 PM standard is
to bring the emission performance of all vehicles to that already being
demonstrated by many vehicles in the current light-duty fleet.
b. Heavy-Duty Vehicle Tailpipe Emissions Standards
    As discussed in detail in Section IV.B, we are setting Tier 3
exhaust emissions standards for complete heavy-duty vehicles (HDVs)
between 8,501 and 14,000 lbs GVWR. Vehicles in this GVWR range are
often referred to as Class 2b (8,501-10,000 lbs) and Class 3 (10,001-
14,000 lbs) vehicles, and are typically heavy-duty pickup trucks and
work or shuttle vans. Most are built by companies with even larger
light-duty truck markets, and as such they frequently share major
design characteristics and emissions control technologies with their
LDT counterparts. However, in contrast to the largely gasoline-fueled
LDT fleet, roughly half of the heavy-duty pickup and van fleet in the
U.S. is diesel-fueled. This is an important consideration in setting
emissions standards, as diesel engine emissions control strategies
differ from those of gasoline engines.
    As proposed, the key elements of the Tier 3 program for HDVs
parallel those being adopted for passenger cars and LDTs, with
adjustments in standard levels, emission test requirements, and
implementation schedules appropriate to this sector. These key elements
include combined NMOG+NOX declining fleet average standards,
a phase-in of PM standards, adoption of a new emissions test fuel for
gasoline-fueled vehicles, extension of the regulatory useful life to
150,000 miles or 15 years (whichever occurs first), and a first-ever
requirement for HDVs to meet standards over an SFTP drive cycle that
addresses real-world driving modes not well-represented by the FTP
cycles.
    We are adopting the Class 2b and Class 3 fleet average
NMOG+NOX standards shown in Table I-4, as proposed. The
standards become more stringent in successive model years from 2018 to
2022, with voluntary standards made available in 2016 and 2017, all of
which are set at levels that match those of California's LEV III
program for these classes of vehicles. Each covered HDV sold by a
manufacturer in each model year contributes to this fleet average based
on the mg/mi NMOG+NOX standard level of the ``bin'' declared
for it by the manufacturer, who chooses from a set of seven discrete
Tier 3 bins specified in the regulations. These bin standards then
become the compliance standards for the vehicle over its useful life,
with some adjustment provided for in-use testing in the early model
years of the program.
    As proposed, manufacturers can also earn credits for fleet average
NMOG+NOX levels below the standard in any model year. Tier 3
credits that were previously banked, obtained from other manufacturers,
or transferred across the Class 2b/Class 3 categories can be used to
help demonstrate compliance. Unused credits expire after 5 model years.
Manufacturers will also be allowed to carry forward deficits in their
credit balance for up to 3 model years.

                                               Table I-4--Tier 3 HDV Fleet Average FTP NMOG+NOX Standards
                                                                         [mg/mi]
--------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                      Voluntary
                                                                   Required program
--------------------------------------------------------------------------------------------------------------------------------------------------------
Model Year....................................       2016       2017       2018       2019       2020       2021  2022 and later.
Class 2b......................................        333        310        278        253        228        203  178.
Class 3.......................................        548        508        451        400        349        298  247.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We are adopting the proposed FTP PM standards of 8 mg/mi and 10 mg/
mi for Class 2b and Class 3 HDVs, respectively, phasing in as an
increasing percentage of a manufacturer's sales per year. We are
adopting the same phase-in schedule as for the light-duty sector during
model years 2018-2019-2020-2021: 20-40-70-100 percent, respectively,
and a more flexible but equivalent alternative PM phase-in is also
being adopted. Tier 3 HDVs will

also be subject to CO and formaldehyde exhaust emissions standards that
are more stringent than the existing standards.
    Finally, we are setting first-ever nationwide SFTP standards for
HDVs to ensure a robust overall control program that precludes high
off-FTP cycle emissions by having vehicle designers consider them in
their choice of compliance strategies. As for light-duty vehicles, we
are requiring that SFTP compliance be based on a weighted composite of
measured emissions from testing over the FTP cycle, the SC03 cycle, and
an aggressive driving cycle, with the latter tailored to various HDV
sub-categories: the US06 cycle for most HDVs, the highway portion of
the US06 cycle for low power-to-weight Class 2b HDVs, and the LA-92 (or
``Unified'') cycle for Class 3 HDVs. The SFTP standards are the same as
those adopted for California LEV III vehicles, and apply to
NMOG+NOX, PM, and CO emissions.
    The HDV program outlined above and described in detail in Section
IV.B is substantially what we proposed. Commenters generally supported
the scope, stringency, and implementation phase-in of this program.
However, some industry commenters requested changes to some specific
provisions of the proposal, and the program we are adopting reflects
improvements we have made in response. These are: (1) A limited
allowance for engine certification of Class 3 complete diesel vehicles
to avoid a potential need for dual chassis- and engine-based
certification and to better harmonize with LEV III, (2) relaxed interim
in-use testing standards to facilitate a smooth transition to the Tier
3 standards and to better harmonize with LEV III, (3) adoption of
combined NMOG+NOX standards for the two highest (interim)
bins, with a restriction placed on NOX levels in
certification testing, to enhance the utility of these bins and to
better harmonize with LEV III, and (4) a provision in the percent-of-
sales phase-in alternative to allow manufacturers to exclude vehicle
models that begin their 2019 model year production early in 2018, in
order to provide four years of lead time. Commenters also requested
relaxed standards for testing at high altitudes and changes to the
credits program structure for generation of early credits and use of
LEV III-based ``vehicle emission credits'', but we did not adopt these
for reasons explained in Section IV.B.
    Overall, we expect the Tier 3 program we are adopting for HDVs to
result in substantial reductions in harmful emissions from this large
fleet of work trucks and vans. The fully-phased in Tier 3 standards
levels for NMOG+NOX and PM are on the order of 60 percent
lower than the current standards that took full effect in the 2009
model year.
c. Evaporative Emission Standards
    Gasoline vapor emissions from vehicle fuel systems occur when a
vehicle is in operation, when it is parked, and when it is being
refueled. These evaporative emissions, which occur on a daily basis
from gasoline-powered vehicles, are primarily functions of temperature,
fuel vapor pressure, and activity. EPA first instituted evaporative
emission standards in the early 1970s to address emissions when
vehicles are parked after being driven. These are commonly referred to
as hot soak plus diurnal emissions. Over the subsequent years the test
procedures have been modified and improved and the standards have
become more numerically stringent. We have addressed emissions which
arose from new fuel system designs by putting in place new requirements
such as running loss emission standards and test procedure provisions
to address permeation emissions. Subsequently standards were put in
place to control refueling emissions from all classes of gasoline-
powered motor vehicles up to 10,000 lbs GVWR. Evaporative and refueling
emission control systems have been in place for most of these vehicles
for many years. These controls have led to significant reductions, but
evaporative and refueling emissions still constitute 30-40 percent of
the summer on-highway mobile source hydrocarbon inventory. These fuel
vapor emissions are ozone and PM precursors, and also contain air
toxics such as benzene.
    To control evaporative emissions, EPA is establishing more
stringent standards that will require covered vehicles to have
essentially zero fuel vapor emissions in use. These include more
stringent evaporative emissions standards, new test procedures, and a
new fuel/evaporative system leak emission standard. The program also
includes refueling emission standards for all complete heavy-duty
gasoline vehicles (HDGVs) over 10,000 lbs GVWR. EPA is including phase-
in flexibilities as well as credit and allowance programs. The
standards, harmonized with California's ``zero evap'' standards, are
designed to allow for a use of common technology in vehicle models sold
throughout the U.S. The level of the standard remains above zero to
account for nonfuel background emissions from the vehicle hardware.
    Requirements to meet the Tier 3 evaporative emission regulations
phase in over a six model year period. We are finalizing three options
for the 2017 model year, but after that the sales percentage
requirements are 60 percent for MYs 2018 and 2019, 80 percent for model
years 2020 and 2021, and 100 percent for model years 2022 and later. In
Table I-5 we present the Tier 3 evaporative hot soak plus diurnal
emission standards by vehicle class. The standards are approximately a
50 percent reduction from the existing standards. To enhance
flexibility and reduce costs, EPA is finalizing provisions that allow
manufacturers to generate allowances through early certifications
(basically before the 2017 model year) and to demonstrate compliance
using averaging concepts. Manufacturers may comply on average within
each of the four vehicle categories, but not across these categories.
EPA is not making any changes to the existing light-duty running loss
or refueling emission standards, with the exception of the
certification test fuel requirement discussed in Section I.B.2 below.

            Table I-5--Tier 3 Evaporative Emission Standards
                                [g/test]
------------------------------------------------------------------------
                                                    Highest hot soak +
                                                   diurnal level  (over
                 Vehicle class                    both 2-day and  3-day
                                                      diurnal tests)
------------------------------------------------------------------------
LDV, LDT1......................................                    0.300
LDT2...........................................                    0.400
LDT3, LDT4, MDPV...............................                    0.500
HDGVs..........................................                    0.600
------------------------------------------------------------------------

    Flexible Fuel Vehicles (FFVs) must meet the same evaporative
emission standards as non-FFVs using Tier 3 emissions certification
test fuel. However, FFVs must meet the refueling emission standards
using 10 psi RVP fuel to account for emissions resulting from
commingling with non-E85 blends that may be in the vehicle's fuel tank.
    EPA is establishing the canister bleed emission test procedure and
emission standard to help ensure fuel vapor emissions are eliminated.
Under this provision, manufacturers are required to measure diurnal
emissions over the 2-day diurnal test procedure from just the fuel tank
and the evaporative emission canister and comply with a 0.020 gram per
test (g/test) standard for all LDVs, LDTs, and MDPVs, without
averaging. The corresponding canister bleed test standard for HDGVs is
0.030 g/test. The Tier 3 evaporative emission standards will be phased
in over a period of six model years between MY 2017 and MY

2022, with the leak test phasing in beginning in 2018.
    Data from in-use evaporative emissions testing indicates that vapor
leaks from vehicle fuel/evaporative systems are found in the fleet and
that even very small leaks have the potential to make significant
contributions to the mobile source VOC inventory. To help address this
issue, we are also adding a new standard and test procedure to control
vapor leaks from vehicle fuel and vapor control systems. The standard
will prohibit leaks with a cumulative equivalent diameter of 0.02
inches or greater. We are adding this simple and inexpensive test and
emission standard to help ensure vehicles maintain zero fuel vapor
emissions over their full useful life. New LDV, LDT, MDPV, and HDGV
equal to or less than 14.000 lbs GVWR meeting the Tier 3 evaporative
emission regulations are also required to meet the leak standard
beginning in the 2018 model year. Manufacturers must comply with the
leak standard phase-in on the same percentage of sales schedule as that
for the Tier 3 evaporative emission standards. Manufacturers will
comply with the leak emission standard during certification and in use.
The leak emission standard does not apply to HDGVs above 14,000 lbs
GVWR.
    EPA is also establishing new refueling emission control
requirements for all complete HDGVs equal to or less than 14,000 lbs
GVWR (i.e., Class 2b/3 HDGVs), starting in the 2018 model year, and for
all larger complete HDGVs by the 2022 model year. The existing
refueling emission control requirements apply to complete Class 2b
HDGVs, and EPA is extending those requirements to other complete HDGVs,
since the fuel and evaporative control systems on these vehicles are
very similar to those on their lighter-weight Class 2b counterparts.
d. Onboard Diagnostic Systems (OBD)
    EPA and CARB both have OBD regulations applicable to the vehicle
classes covered by the Tier 3 emission standards. In the past the
requirements have been very similar, so most manufacturers have met
CARB OBD requirements and, as permitted in our regulations, EPA has
generally accepted compliance with CARB's OBD requirements as
satisfying EPA's OBD requirements. Over the past several years CARB has
upgraded its requirements to help improve the effectiveness of OBD in
ensuring good in-use exhaust and evaporative system emissions
performance. We have reviewed these provisions and agree with CARB that
these revisions will help to improve in-use emissions performance,
while at the same time harmonizing with the CARB program. Toward that
end, we are adopting and incorporating by reference the current CARB
OBD regulations, effective for the 2017 MY, with a few minor
differences including phase-in flexibility provisions and specific
additions to enhance the implementation of the leak standard. EPA is
retaining the provision that certifying with CARB's program would
permit manufacturers to seek a separate EPA certificate on that basis.
e. Emissions Test Fuel
    As described above, after reassessing market trends and considering
comments, EPA is finalizing E10 as the ethanol blend level in emissions
test gasoline for Tier 3 light-duty and heavy-duty gasoline vehicles.
We will continue to monitor the in-use gasoline supply and based on
such review may initiate rulemaking action to revise the specifications
for emissions test fuel to include a higher ethanol blend level. EPA is
also making additional changes that are consistent with CARB's LEV III
emissions test fuel specifications, including new specifications for
octane, distillation temperatures, aromatics, olefins, sulfur and
benzene. (See Section IV.F below for a detailed discussion of all the
revised emission test fuel parameters.)
    As discussed in Sections IV.A.7.d (tailpipe emission testing) and
IV.C.5.b (evaporative emission testing), we are requiring certification
of all Tier 3 light-duty and chassis-certified heavy-duty gasoline
vehicles on federal E10 test fuel. The new test fuel specifications
will apply to new vehicle certification, assembly line, and in-use
testing.
    With a change in the ethanol content of the test fuel, EPA also
needed to consider whether a change is warranted in the volatility of
the test fuel, typically expressed as pounds per square inch (psi) Reid
Vapor Pressure (RVP). As discussed in detail in Section IV.F below,
after considering several technical and policy implications as well as
stakeholder comments, EPA has concluded that the most appropriate
approach is to maintain an RVP of 9 psi for the E10 certification fuel
at this time.
    In addition to finalizing a new E10 emissions test fuel, we are
also finalizing detailed specifications for the E85 emissions test fuel
used for flexible fuel vehicle (FFV) certification, as discussed in
Section IV.F.3.\15\ This will resolve uncertainty and confusion in the
certification of FFVs designed to operate on ethanol levels up to 83
percent. Furthermore, we allow vehicle manufacturers to request
approval for an alternative certification fuel such as a high-octane 30
percent ethanol by volume blend (E30) for vehicles that may be
optimized for such fuel.
---------------------------------------------------------------------------

    \15\ Flexible fuel vehicles are currently required to meet
emissions certification requirements using both E0 and E85 test
fuels. However, there were no detailed regulatory specifications
regarding the composition of E85 test fuels before those finalized
today.
---------------------------------------------------------------------------

f. Fuel Standards
    Under the Tier 3 fuel program, gasoline must contain no more than
10 ppm sulfur on an annual average basis beginning January 1, 2017.
Similar to the Tier 2 gasoline program, the Tier 3 program will apply
to gasoline in the U.S. and the U.S. territories of Puerto Rico and the
Virgin Islands, excluding California. The program will result in
gasoline that contains, on average, two-thirds less sulfur than it does
today. In addition, following discussions with numerous refiners and
other segments of the fuel market (e.g., pipelines, terminals,
marketers, ethanol industry representatives, transmix processors,
additive manufacturers, etc.), the Tier 3 fuel program contains
considerable flexibility to ease both initial and long-term
implementation of the program. The program that we are finalizing today
includes an averaging, banking, and trading (ABT) program that allows
refiners and importers to spread out their investments over nearly a 6-
year period through the use of an early credit program and then rely on
ongoing nationwide averaging to meet the 10 ppm sulfur standard. In
addition there is a three-year delay for small refiners and ``small
volume refineries''. As a result of the early credit program, we
anticipate considerable reductions in gasoline sulfur levels prior to
2017, with a complete transition to the 10 ppm average occurring by
January 1, 2020. For more information on the gasoline sulfur program
flexibilities, refer to Section V.E.
    Under today's Tier 3 gasoline sulfur program, we are maintaining
the current 80 ppm refinery gate and 95 ppm downstream per-gallon caps.
We also evaluated and sought comment on the potential of lowering the
per-gallon caps. While there are advantages and disadvantages with each
of the sulfur cap options that we proposed, we believe that retaining
the current Tier 2 sulfur caps is prudent at this time, as explained in
more detail in Section V.C. Further, the stringency of the 10 ppm
annual average standard will result in reduced gasoline sulfur levels
nationwide. Today's program requires

that manufacturers of gasoline additives that are used downstream of
the refinery at less than 1 volume percent must limit the sulfur
contribution to the finished gasoline from the use of their additive to
less than 3 ppm when the additive is used at the maximum recommended
treatment rate (see Section V.C.2). This requirement will preclude the
unnecessary use of high sulfur content additives in gasoline.
    The vehicle emissions standards finalized today are fuel-neutral
(i.e., they are applicable regardless of the type of fuel that the
vehicle is designed to use). There currently are no sulfur standards
for the fuel used in compressed natural gas (CNG) and liquid propane
gas (LPG) vehicles. We requested comment on whether it is necessary for
EPA to establish sulfur standards for CNG and LPG to enable them
meeting more stringent vehicle emissions standards. EPA is deferring
finalizing in-use sulfur requirements for CNG/LPG in this final rule to
provide additional time to work with stakeholders to collect data on
current CNG/LPG sulfur content, to determine whether additional control
of in-use CNG/LPG sulfur content is needed, and to evaluate the
feasibility and costs associated with potential additional sulfur
controls (see Section V.J). Given that the information provided
suggests that CNG/LPG sulfur levels tend to be low already, the vehicle
emissions standards finalized today will apply to CNG/LPG vehicles in
addition to vehicles fueled on gasoline, diesel fuel, or any other
fuel. The sulfur content of highway diesel fuel is already required to
meet a 15 ppm sulfur cap, which is sufficient for diesel fuel vehicles
to meet the Tier 3 emissions standards.
    As the number of flex-fuel vehicles (FFVs) in the in-use fleet
increases, it is becoming increasingly important that all fuels used in
FFVs, not just gasoline, meet fuel quality standards. A lack of clarity
regarding the standards that apply to fuels used in FFVs could also act
to impede the further expansion of ethanol blended fuels with
concentrations greater than 15 volume percent, which is important to
satisfying the requirements of the RFS2 program. Hence, we sought
comment on appropriate regulatory mechanisms to implement in-use
quality standards for E51-83 and E16-50 in the Tier 3 proposal.
Additional work is needed on some issues that could not be accommodated
within the timeline for this Tier 3 final rule. Therefore, we are
choosing not to finalize these provisions at this time. We intend to
finalize in-use fuel quality standards for E51-83 and perhaps E16-50 as
well in a follow-up final rule.
g. Regulatory Streamlining and Technical Amendments
    This action also includes a number of items to help streamline the
in-use fuels regulations at 40 CFR parts 79 and 80. The majority of
these items involve clarifying vague or inconsistent language, removal
or updating of outdated provisions, and decreasing in frequency and/or
volume of reporting burden where data are no longer needed or are
redundant with other EPA fuels programs. In general, we believe that
these changes will reduce the burden on industry and allow the
standards and resulting environmental benefits to be achieved as early
as possible with no expected loss in environmental control. In some
cases, these regulatory streamlining items are non-substantive
amendments that correct minor errors or inconsistencies in the
regulations.
    The regulatory streamlining items that we are finalizing for the
in-use fuels regulations are changes that we believe are
straightforward and should be made quickly.
    This action also includes a variety of technical amendments to
certification-related requirements for engine and vehicle emission
standards; adjusting the fuel economy label provisions to correspond to
the new Tier 3 standards, removing obsolete regulatory text, and making
several minor corrections and clarifications.
    Please refer to Section VI for a complete discussion of technical
amendments and regulatory streamlining provisions and issues.

C. What will the impacts of the standards be?

    The final Tier 3 vehicle and fuel standards together will reduce
dramatically emissions of NOX, VOC, PM2.5, and
air toxics. The gasoline sulfur standards, which will take effect in
2017, will provide large immediate reductions in emissions from
existing gasoline vehicles and engines. NOX emissions are
projected to be reduced by about 260,000 tons, or about 10 percent of
emissions from on-highway vehicles, in 2018, and these emission
reductions will increase over time as newer vehicles become a larger
percentage of the fleet. In 2030, when 70 percent of the miles
travelled are projected to be from vehicles that meet the fully phased-
in Tier 3 standards, we expect the NOX and VOC emissions to
be reduced by about 330,000 tons and 170,000 tons, respectively, or 25
percent and 16 percent of emissions from on-highway vehicles compared
to their 2030 levels without the Tier 3 program. Emissions of CO are
projected to decrease by almost 3.5 million tons, or 24 percent of
emissions from on-highway vehicles. Emissions of many air toxics will
also be reduced, including benzene, 1,3-butadiene, acetaldehyde,
formaldehyde, acrolein and ethanol, with reductions projected to range
from 10 to nearly 30 percent of national emissions from on-highway
vehicles. We expect these reductions to continue beyond 2030 as more of
the fleet continues to turn over to Tier 3 vehicles; for example, by
2050, when nearly all of the fleet will have turned over to vehicles
meeting the fully phased-in Tier 3 standards, we estimate the Tier 3
program will reduce on-highway emissions of NOX and VOC
nearly 31 percent from the level of emissions projected without Tier 3
controls.\16\
---------------------------------------------------------------------------

    \16\ To estimate the benefits of the final Tier 3 rule, we
performed air quality modeling for the year 2030.
---------------------------------------------------------------------------

    These reductions in emissions of NOX, VOC,
PM2.5 and air toxics from the Tier 3 standards are projected
to lead to significant decreases in ambient concentrations of ozone,
PM2.5 and air toxics (including notable nationwide
reductions in benzene concentrations) by 2030, and will immediately
reduce ozone in 2017 when the sulfur controls take effect. Additional
information on the emission and air quality impacts of the final Tier 3
program is presented in Sections III.B and C.
    Exposure to ambient concentrations of ozone, PM2.5, and
air toxics is linked to adverse human health impacts such as premature
deaths as well as other important public health and environmental
effects (see Section II.B). The final Tier 3 standards are expected to
reduce these adverse impacts and yield significant benefits, including
those we can monetize and those we are unable to quantify. We estimate
that by 2030, the emission reductions of the Tier 3 standards will
annually prevent between 660 and 1,500 PM-related premature deaths,
between 110 and 500 ozone-related premature deaths, 81,000 work days
lost, 210,000 school absence days, and approximately 1.1 million minor
restricted-activity days. The estimated annual monetized health
benefits of the Tier 3 standards in 2030 (2011$) is between $7.4 and
$19 billion, assuming a 3-percent discount rate (or between $6.7
billion and $18 billion assuming a 7-percent discount rate). We project
the final fuel standards to cost on average 0.65 cent (i.e., less than
a penny) per gallon of gasoline, and the final vehicle standards to
have an

average cost that increases in proportion to the increase in stringency
during the phase-in period, from $28 per vehicle in 2017 to $72 per
vehicle in 2025, when the standards are fully phased in. We estimate
the annual cost of the overall program in 2030 will be approximately
$1.5 billion, and the 2030 benefits will be between 4.5 and 13 times
the costs of the program.
    The estimated benefits in Table I-6 include all of the human health
impacts we are able to quantify and monetize at this time. However, the
full complement of human health and welfare effects associated with PM,
ozone and air toxics remain unquantified because of current limitations
in methods and/or available data. As a result, the health benefits
quantified in this section are likely underestimates of the total
benefits attributable to the final standards. See Sections VII and VIII
for detailed descriptions of the costs and benefits of this action.

  Table I-6--Summary of Estimated Annual Benefits and Costs Associated
                      With the Final Tier 3 Program
                          [Billions, 2011$] \a\
------------------------------------------------------------------------
                         Description                              2030
------------------------------------------------------------------------
Vehicle Program Costs........................................      $0.76
Fuels Program Costs..........................................      $0.70
Total Estimated Costs \b\....................................       $1.5
Total Estimated Health Benefits: \c\ \d\ \e\ \f\
    3 percent discount rate..................................   $7.4-$19
    7 percent discount rate..................................   $6.7-$18
Annual Net Benefits (Total Benefits-Total Costs):
    3 percent discount rate..................................   $5.9-$18
    7 percent discount rate..................................   $5.2-$17
------------------------------------------------------------------------
Notes:
\a\ All estimates represent annual benefits and costs anticipated for
  the year 2030. Totals are rounded to two significant digits and may
  not sum due to rounding.
\b\ The calculation of annual costs does not require amortization of
  costs over time. Therefore, the estimates of annual cost do not
  include a discount rate or rate of return assumption (see Section VII
  of the preamble for more information on vehicle and fuel costs).
\c\ Total includes ozone and PM[ihel2].[ihel5] estimated benefits. Range
  was developed by adding the estimate from the Bell et al., 2004 ozone
  premature mortality function to PM[ihel2].[ihel5]-related premature
  mortality derived from the American Cancer Society cohort study
  (Krewski et al., 2009) for the low estimate and ozone premature
  mortality derived from the Levy et al., 2005 study to
  PM[ihel2].[ihel5]-related premature mortality derived from the Six-
  Cities (Lepeule et al., 2012) study for the high estimate.
\d\ Annual benefits analysis results reflect the use of a 3 percent and
  7 percent discount rate in the valuation of premature mortality and
  nonfatal myocardial infarctions, consistent with EPA and OMB
  guidelines for preparing economic analyses.
\e\ Valuation of premature mortality based on long-term PM exposure
  assumes discounting over the SAB recommended 20-year segmented lag
  structure described in the Regulatory Impact Analysis for the 2012 PM
  National Ambient Air Quality Standards (December, 2012).
\f\ Not all possible benefits are quantified and monetized in this
  analysis; the total monetized benefits presented here may therefore be
  underestimated. Potential benefit categories that have not been
  quantified and monetized, due to current limitations in methods and/or
  data availability, are listed in Table VIII-2. For example, we have
  not quantified a number of known or suspected health and welfare
  effects linked with reductions in ozone and PM (e.g., reductions in
  heart rate variability, reduced material damage to structures and
  cultural monuments, and reduced eutrophication in coastal areas). We
  are also unable to quantify health and welfare benefits associated
  with reductions in air toxics.

II. Why is EPA taking this action?

    The Clean Air Act authorizes EPA to establish emissions standards
for motor vehicles to address air pollution that may reasonably be
anticipated to endanger public health or welfare. EPA also has
authority to establish fuel controls to address such air pollution.
These statutory requirements are described in Section II.A.
    Emissions from motor vehicles and their fuels contribute to ambient
levels of ozone, PM, NO2, sulfur dioxide (SO2)
and CO, which are all pollutants for which EPA has established health-
based NAAQS. These pollutants are linked with respiratory and/or
cardiovascular problems and other adverse health impacts leading to
increased medication use, hospital admissions, emergency department
visits, and premature mortality. Over 149 million people currently live
in areas designated nonattainment for one or more of the current NAAQS
for ozone, PM2.5, PM10, and SO2.\17\
---------------------------------------------------------------------------

    \17\ Data come from Summary Nonattainment Area Population
Exposure Report, current as of December 5, 2013 at: http://www.epa.gov/oar/oaqps/greenbk/popexp.html and contained in Docket
EPA-HQ-OAR-2011-0135.
---------------------------------------------------------------------------

    Motor vehicles also emit air toxics, and the most recent available
data indicate that the majority of Americans continue to be exposed to
ambient concentrations of air toxics at levels which have the potential
to cause adverse health effects, including cancer, immune system
damage, and neurological, reproductive, developmental, respiratory, and
other health problems.\18\ A more detailed discussion of the health and
environmental effects of these pollutants is included in Section II.B.
---------------------------------------------------------------------------

    \18\ U.S. EPA. (2011) Summary of Results for the 2005 National-
Scale Assessment. www.epa.gov/ttn/atw/nata2005/05pdf/sum_results.pdf.
---------------------------------------------------------------------------

    Cars and light trucks also continue to be a significant contributor
to air pollution directly near roads, with gasoline vehicles accounting
for more than 50 percent of near-road concentrations of some criteria
and toxic pollutants.\19\ More than 50 million people live, work, or go
to school in close proximity to high-traffic roadways, and the average
American spends more than one hour traveling each day, with over 80
percent of daily trips occurring by personal vehicle.\20\ \21\ \22\
\23\ \24\ Exposure to traffic-related pollutants has been linked with
adverse health impacts such as respiratory problems (particularly in
asthmatic children) and cardiovascular problems.
---------------------------------------------------------------------------

    \19\ For example, see Fujita, E.M; Campbell, D.E.; Zielinska,
B.; Arnott, W.P.; Chow, J.C. (2011) Concentrations of Air Toxics in
Motor Vehicle-Dominated Environments. Health Effects Institute
Research Report 156. Available at http://www.healtheffects.org.
    \20\ Rowangould, G.M. (2013) A census of the US near-roadway
population: public health and environmental justice considerations.
Transportation Research Part D 25: 59-67.
    \21\ U.S. Census Bureau (2011). Current Housing Reports, Series
H150/09, American Housing Survey for the United States: 2009. U.S.
Government Printing Office, Washington, DC. Available at http://www.census.gov/hhes/www/housing/ahs/ahs09/ahs09.html.
    \22\ Drago, R.(2011). Secondary activities in the 2006 American
Time Use Survey. U.S. Bureau of Labor Statistics Working Paper 446.
Available at http://www.bls.gov.
    \23\ U.S. Department of Transportation, Bureau of Transportation
Statistics. (2003) National Household Travel Survey 2001 Highlights
Report. Government Printing Office, Washington, DC. Available at
http://www.bts.gov/publications/highlights_of_the_2001_national_household_travel_survey/.
    \24\ Santos, A.; McGuckin, N, Yukiko Nakamoto, H.; Gray, D.;
Liss, S. (2011) Summary of Travel Trends: 2009 National Household
Travel Survey. Federal Highway Administration report no FHWA-PL-11-
022. Available at http://nhts.ornl.gov/publications.shtml.
---------------------------------------------------------------------------

    In the absence of additional controls such as Tier 3 standards,
many areas will continue to have ambient ozone and PM2.5
concentrations exceeding the NAAQS in the future. States and local
areas are required to adopt control measures to attain the NAAQS and,
once attained, to demonstrate that control measures are in place
sufficient to maintain the NAAQS for ten years (and eight years later,
a similar demonstration is required for another ten-year period). The
Tier 3 standards will be a critical part of many areas' strategies to
attain and maintain the NAAQS. Maintaining the NAAQS has been
challenging for some areas in the past, particularly those where high
population growth rates lead to significant annual increases in vehicle
trips and vehicle miles traveled. Our air quality modeling for this
final rule, which is described in more detail in Section III.C,
projects that in 2018 a significant number of counties outside

CA will be within 10 percent of the 2008 ozone NAAQS, in the absence of
additional controls. These counties in particular will benefit from the
Tier 3 standards as they work to ensure long-term maintenance of the
NAAQS.
    Section III provides more detail on how we expect this action will
reduce motor vehicle emissions and ambient levels of pollution. We
project that the Tier 3 program will meaningfully reduce ozone
concentrations as early as 2017 (the first year of the program), and
even more significantly in 2030. The estimated reductions are of
significant enough magnitude to bring ozone levels in some counties
from above the standard to below the standard, even without any
additional controls. We also project that the Tier 3 standards will
reduce ambient PM2.5 concentrations.
    Without this action to reduce nationwide motor vehicle emissions,
areas would have to adopt other measures to reduce emissions from other
sources under their state or local authority. Few other measures exist
for providing multi-pollutant reductions of the same magnitude and
cost-effectiveness as those expected from the Tier 3 standards.
Furthermore, most states do not have the authority to lower the sulfur
in gasoline, which is needed to immediately reduce emissions from the
existing fleet and also enable new vehicles to meet the Tier 3
emissions standards throughout their useful life.
    The projected reductions in ambient ozone and PM2.5 that
will result from the Tier 3 standards will provide significant health
benefits. We estimate that by 2030, the standards will annually prevent
between 660 and 1,500 PM-related premature deaths, between 110 and 500
ozone-related premature deaths, 81,000 work days lost, 210,000 school
absence days, and approximately 1.1 million minor restricted-activity
days (see Section VIII for more details). This action will also reduce
air toxics; for example, we project that in 2030, the Tier 3 standards
will decrease ambient benzene concentrations by 10-25 percent in some
urban areas. Furthermore, the Tier 3 standards will reduce traffic-
associated pollution near major roads.
    EPA is finalizing Tier 3 vehicle and fuel standards as part of a
comprehensive nationwide program for regulating all types of air
pollution from motor vehicles. EPA recently finalized standards to
reduce GHG emissions from light-duty vehicles, starting with model year
2017.\25\ The Tier 3 standards in this final rule, which address non-
GHGs, will be implemented on the same timeframe, thus allowing
manufacturers to optimize their vehicle redesigns over both sets of
standards. Furthermore, the Tier 3 vehicle and fuel standards are also
closely aligned with California's LEV III program, in such a way that
manufacturers will be able to design a single vehicle for nationwide
sales. This reduces the cost of compliance for auto manufacturers.
---------------------------------------------------------------------------

    \25\ 77 FR 62623 (October 15, 2012).
---------------------------------------------------------------------------

    This Tier 3 rulemaking responds to the President's request in his
May 2010 memorandum for EPA to review the adequacy of its existing non-
GHG standards for new motor vehicles and fuels, and to promulgate new
standards, if necessary, as part of a comprehensive approach to
regulating motor vehicles.\26\ Based on our review, we have concluded
that improved vehicle technology, combined with lower sulfur gasoline,
make it feasible and cost-effective to reduce emissions well below the
current Tier 2 levels. These emission reductions are necessary to
reduce air pollution that is (and projected to continue to be) at
levels that endanger public health and welfare.
---------------------------------------------------------------------------

    \26\ The Presidential Memorandum is found at: http://www.whitehouse.gov/the-press-office/presidential-memorandum-regarding-fuel-efficiency-standards.
---------------------------------------------------------------------------

A. Basis for Action Under the Clean Air Act

1. Clean Air Act Section 202
    We are setting motor vehicle emission standards under the authority
of section 202 of the Clean Air Act. Section 202(a) provides EPA with
general authority to prescribe vehicle standards, subject to any
specific limitations elsewhere in the Act. EPA is setting standards for
larger light-duty trucks and MDPVs under the general authority of
section 202(a)(1) and under section 202(a)(3), which requires that
standards applicable to emissions of hydrocarbons, NOX, CO
and PM from heavy-duty vehicles \27\ reflect the greatest degree of
emission reduction available for the model year to which such standards
apply, giving appropriate consideration to cost, energy, and safety. In
addition, section 202(k) provides EPA with authority to issue and
revise regulations applicable to evaporative emissions of hydrocarbons
from all gasoline-fueled motor vehicles during: (1) Operation, and (2)
over 2 or more days of nonuse; under ozone-prone summertime conditions.
Regulations under section 202(k) shall take effect as expeditiously as
possible and shall require the greatest degree of emission reduction
achievable by means reasonably expected to be available for production
during any model year to which the regulations apply, giving
appropriate consideration to fuel volatility, and to cost, energy, and
safety factors associated with the application of the appropriate
technology. Further, section 206 and in particular section 206(d) of
the Clean Air Act authorizes EPA to establish methods and procedures
for testing whether a motor vehicle or motor vehicle engine conforms
with section 202 requirements.
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    \27\ LDTs that have gross vehicle weight ratings above 6000 lbs
and all MDPVs are considered ``heavy-duty vehicles'' under the CAA.
See section 202(b)(3)(C). For regulatory purposes, we generally
refer to those LDTs which are above 6000 lbs GVWR and at or below
8500 lbs GVWR as ``heavy light-duty trucks'' made up of LDT3s and
LDT4s, and we have defined MDPVs primarily as vehicles between 8500
and 10000 lbs GVWR designed primarily for the transportation of
persons. See 40 CFR 86.1803-01.
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2. Clean Air Act Section 211
    We are adopting gasoline sulfur controls pursuant to our authority
under section 211(c)(1) of the CAA. This section allows EPA to
establish a fuel control if at least one of the following two criteria
is met: (1) The emission products of the fuel cause or contribute to
air pollution which may reasonably be anticipated to endanger public
health or welfare; or (2) the emission products of the fuel will impair
to a significant degree the performance of any emissions control device
or system which is either in general use or which the Administrator
finds has been developed to a point where in a reasonable time it will
be in general use were the fuel control to be adopted. We are
finalizing gasoline sulfur controls based on both of these criteria.
Under the first criterion, we believe that gasoline with current levels
of sulfur contributes to ambient levels of air pollution that endanger
public health and welfare, as described in Section II.B. Under the
second criterion, we believe that gasoline sulfur impairs the emissions
control systems of vehicles, as discussed in Section III.A.2.

B. Overview of Public Health Impacts of Motor Vehicles and Fuels

    Motor vehicles emit pollutants that contribute to ambient
concentrations of ozone, PM, NO2, SO2, CO, and
air toxics. Motor vehicles are significant contributors to emissions of
VOC and NOX, which contribute to the formation of both ozone
and PM2.5. Over 149 million people currently live in
counties designated nonattainment for one or more of the NAAQS, and
this figure does not include the people living in areas with a risk of
exceeding the

NAAQS in the future.\28\ The majority of Americans continue to be
exposed to ambient concentrations of air toxics at levels which have
the potential to cause adverse health effects.\29\ In addition,
populations who live, work, or attend school near major roads
experience elevated exposure concentrations to a wide range of air
pollutants.\30\
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    \28\ Data come from Summary Nonattainment Area Population
Exposure Report, current as of December 5, 2013 at: http://www.epa.gov/oar/oaqps/greenbk/popexp.html and contained in Docket
EPA-HQ-OAR-2011-0135.
    \29\ U.S. EPA. (2011) Summary of Results for the 2005 National-
Scale Assessment. www.epa.gov/ttn/atw/nata2005/05pdf/sum_results.pdf.
    \30\ Health Effects Institute Panel on the Health Effects of
Traffic-Related Air Pollution. (2010) Traffic-related air pollution:
a critical review of the literature on emissions, exposure, and
health effects. HEI Special Report 17. Available at http://www.healtheffects.org].
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    EPA has already adopted many emission control programs that are
expected to reduce ambient pollution concentrations. As a result of
these programs, the number of areas that continue to violate the ozone
and PM2.5 NAAQS or have high levels of air toxics is
expected to continue to decrease. However, the baseline air quality
modeling completed for this rule predicts that without additional
controls there will continue to be a need for reductions in ozone,
PM2.5 and air toxics concentrations in some locations in the
future. Section III.C of this preamble presents the air quality
modeling results for this action.
1. Ozone
a. Background
    Ground-level ozone pollution is typically formed through reactions
involving VOC and NOX in the lower atmosphere in the
presence of sunlight. These pollutants, often referred to as ozone
precursors, are emitted by many types of pollution sources, such as
highway and nonroad motor vehicles and engines, power plants, chemical
plants, refineries, makers of consumer and commercial products,
industrial facilities, and smaller area sources.
    The science of ozone formation, transport, and accumulation is
complex. Ground-level ozone is produced and destroyed in a cyclical set
of chemical reactions, many of which are sensitive to temperature and
sunlight. When ambient temperatures and sunlight levels remain high for
several days and the air is relatively stagnant, ozone and its
precursors can build up and result in more ozone than typically occurs
on a single high-temperature day. Ozone and its precursors can be
transported hundreds of miles downwind from precursor emissions,
resulting in elevated ozone levels even in areas with low local VOC or
NOX emissions.
b. Health Effects of Ozone
    This section provides a summary of the health effects associated
with exposure to ambient concentrations of ozone.\31\ The information
in this section is based on the information and conclusions in the
February 2013 Integrated Science Assessment for Ozone (Ozone ISA)
prepared by EPA's Office of Research and Development (ORD).\32\ The
Ozone ISA concludes that human exposures to ambient concentrations of
ozone are associated with a number of adverse health effects and
characterizes the weight of evidence for these health effects.\33\ The
discussion below highlights the Ozone ISA's conclusions pertaining to
health effects associated with both short-term and long-term periods of
exposure to ozone.
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    \31\ Human exposure to ozone varies over time due to changes in
ambient ozone concentration and because people move between
locations which have notable different ozone concentrations. Also,
the amount of ozone delivered to the lung is not only influenced by
the ambient concentrations but also by the individuals breathing
route and rate.
    \32\ U.S. EPA. Integrated Science Assessment of Ozone and
Related Photochemical Oxidants (Final Report). U.S. Environmental
Protection Agency, Washington, DC, EPA/600/R-10/076F, 2013. The ISA
is available at http://cfpub.epa.gov/ncea/isa/recordisplay.cfm?deid=247492#Download.
    \33\ The ISA evaluates evidence and draws conclusions on the
causal relationship between relevant pollutant exposures and health
effects, assigning one of five ``weight of evidence''
determinations: causal relationship, likely to be a causal
relationship, suggestive of a causal relationship, inadequate to
infer a causal relationship, and not likely to be a causal
relationship. For more information on these levels of evidence,
please refer to Table II in the Preamble of the ISA.
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    For short-term exposure to ozone, the Ozone ISA concludes that
respiratory effects, including lung function decrements, pulmonary
inflammation, exacerbation of asthma, respiratory-related hospital
admissions, and mortality, are causally associated with ozone exposure.
It also concludes that cardiovascular effects, including decreased
cardiac function and increased vascular disease, and total mortality
are likely to be causally associated with short-term exposure to ozone
and that evidence is suggestive of a causal relationship between
central nervous system effects and short-term exposure to ozone.
    For long-term exposure to ozone, the Ozone ISA concludes that
respiratory effects, including new onset asthma, pulmonary inflammation
and injury, are likely to be a causally related with ozone exposure.
The Ozone ISA characterizes the evidence as suggestive of a causal
relationship for associations between long-term ozone exposure and
cardiovascular effects, reproductive and developmental effects, central
nervous system effects and total mortality. The evidence is inadequate
to infer a causal relationship between chronic ozone exposure and
increased risk of lung cancer.
    Finally, interindividual variation in human responses to ozone
exposure can result in some groups being at increased risk for
detrimental effects in response to exposure. The Ozone ISA identified
several groups that are at increased risk for ozone-related health
effects. These groups are people with asthma, children and older
adults, individuals with reduced intake of certain nutrients (i.e.,
Vitamins C and E), outdoor workers, and individuals having certain
genetic variants related to oxidative metabolism or inflammation. Ozone
exposure during childhood can have lasting effects through adulthood.
Such effects include altered function of the respiratory and immune
systems. Children absorb higher doses (normalized to lung surface area)
of ambient ozone, compared to adults, due to their increased time spent
outdoors, higher ventilation rates relative to body size, and a
tendency to breathe a greater fraction of air through the mouth.
Children also have a higher asthma prevalence compared to adults.
Additional children's vulnerability and susceptibility factors are
listed in Section XII.G.
c. Current and Projected Concentrations of Ozone
    Concentrations that exceed the level of the ozone NAAQS occur in
many parts of the country, including major population centers such as
Atlanta, Baltimore, Chicago, Dallas, Houston, New York, Philadelphia,
and Washington, DC. In addition, our modeling without the Tier 3
controls projects that in the future we will continue to have many
counties that will have ambient ozone concentrations above the level of
the NAAQS (see Section III.C.1). States will need to meet the standard
in the 2015-2032 time frame for the 2008 ozone NAAQS. The emission
reductions and significant ambient ozone improvements from this rule,
which will take effect starting in 2017, will be helpful to states as
they work to attain and maintain the ozone NAAQS.
    The primary and secondary NAAQS for ozone are 8-hour standards with
a level of 0.075 ppm. The most recent revision to the ozone standards
was in 2008; the previous 8-hour ozone standards, set in 1997, had a
level of 0.08 ppm. In 2004, the U.S. EPA

designated nonattainment areas for the 1997 8-hour ozone NAAQS.\34\
\35\ As of December 5, 2013, there were 39 ozone nonattainment areas
for the 1997 ozone NAAQS composed of 216 full or partial counties with
a total population of over 112 million. Nonattainment designations for
the 2008 ozone standard were finalized on April 30, 2012 and May 31,
2012.\36\ As of December 5, 2013, there were 46 ozone nonattainment
areas for the 2008 ozone NAAQS, composed of 227 full or partial
counties, with a population of over 123 million. As of December 5,
2013, over 135 million people are living in ozone nonattainment
areas.\37\
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    \34\ 69 FR 23858 (April 30, 2004).
    \35\ A nonattainment area is defined in the Clean Air Act (CAA)
as an area that is violating an ambient standard or is contributing
to a nearby area that is violating the standard.
    \36\ 77 FR 30088 (May 21, 2012) and 77 FR 34221 (June 11, 2012).
    \37\ The 135 million total is calculated by summing, without
double counting, the 1997 and 2008 ozone nonattainment populations
contained in the Summary Nonattainment Area Population Exposure
report (http://www.epa.gov/oar/oaqps/greenbk/popexp.html). If there
is a population associated with both the 1997 and 2008 nonattainment
areas, and they are not the same, then the larger of the two
populations is included in the sum.
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    States with ozone nonattainment areas are required to take action
to bring those areas into attainment. The attainment date assigned to
an ozone nonattainment area is based on the area's classification. Most
ozone nonattainment areas were required to attain the 1997 8-hour ozone
NAAQS in the 2007 to 2013 time frame and then to maintain it
thereafter.\38\ The attainment dates for areas designated nonattainment
for the 2008 8-hour ozone NAAQS are in the 2015 to 2032 timeframe,
depending on the severity of the problem in each area. In addition, EPA
is currently working on a review of the ozone NAAQS. If EPA revises the
ozone standards pursuant to that review, the attainment dates
associated with areas designated nonattainment for that NAAQS would be
5 or more years after the final rule is promulgated, depending on the
severity of the problem in each area.
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    \38\ The Los Angeles South Coast Air Basin 8-hour ozone
nonattainment area and the San Joaquin Valley Air Basin 8-hour ozone
nonattainment area are designated as Extreme and will have to attain
before June 15, 2024. The Sacramento, Coachella Valley, Western
Mojave and Houston 8-hour ozone nonattainment areas are designated
as Severe and will have to attain by June 15, 2019.
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    EPA has already adopted many emission control programs that are
expected to reduce ambient ozone levels. As a result of these and other
federal, state and local programs, 8-hour ozone levels are expected to
improve in the future. However, even with the implementation of all
current state and federal regulations, there are projected to be
counties violating the ozone NAAQS well into the future. Thus
additional federal control programs, such as Tier 3, can assist areas
with attainment dates in 2018 and beyond in attaining the NAAQS as
expeditiously as practicable and may relieve areas with already
stringent local regulations from some of the burden associated with
adopting additional local controls.
2. Particulate Matter
a. Background
    Particulate matter 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-\9\ meter) to over 100
micrometer ([mu]m, or 10-\6\ 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,
including ultrafine particles (<0.1 [mu]m), accumulation mode or `fine'
particles (<1 to 3 [mu]m), and coarse particles (>1 to 3 [mu]m).\39\
For regulatory purposes, fine particles are measured as
PM2.5 and inhalable or thoracic coarse particles are
measured as PM10-2.5, corresponding to their size (diameter)
range in micrometers. The EPA currently has standards that measure
PM2.5 and PM10.\40\
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    \39\ U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F. Figure 3-1.
    \40\ Regulatory definitions of PM size fractions, and
information on reference and equivalent methods for measuring PM in
ambient air, are provided in 40 CFR Parts 50, 53, and 58. With
regard to national ambient air quality standards (NAAQS) which
provide protection against health and welfare effects, the 24-hour
PM10 standard provides protection against effects
associated with short-term exposure to thoracic coarse particles
(i.e., PM10-2.5).
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    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; 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. A further layer of complexity
comes from particles' ability to shift between solid/liquid and gaseous
phases, which is influenced by concentration and meteorology,
especially temperature.
    Fine particles are produced primarily by combustion processes and
by transformations of gaseous emissions (e.g., sulfur oxides
(SOX), oxides of nitrogen, and volatile organic compounds
(VOC)) in the atmosphere. The chemical and physical properties of
PM2.5 may vary greatly with time, region, meteorology, and
source category. Thus, PM2.5 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 hundreds to
thousands of kilometers.
b. Health Effects of PM
    Scientific studies show ambient PM is associated with a broad range
of health effects. These health effects are discussed in detail in the
December 2009 Integrated Science Assessment for Particulate Matter (PM
ISA).\41\ The PM ISA summarizes health effects evidence associated with
both short- and long-term exposures to PM2.5,
PM10-2.5, and ultrafine particles. The PM ISA concludes that
human exposures to ambient PM2.5 concentrations are
associated with a number of adverse health effects and characterizes
the weight of evidence for these health outcomes.\42\ The discussion
below highlights the PM ISA's conclusions pertaining to health effects
associated with both short- and long-term PM exposures. Further
discussion of health effects associated with PM2.5 can also
be found in the rulemaking documents for the most recent review of the
PM NAAQS completed in 2012.43 44
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    \41\ U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F.
    \42\ 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