Thursday,

February 10, 2000

Part II

Environmental

Protection Agency

40 CFR Parts 80, 85, and 86

Control of Air Pollution From New Motor

Vehicles: Tier 2 Motor Vehicle Emissions

Standards and Gasoline Sulfur Control

Requirements; Final Rule

6698 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Parts 80, 85, and 86

[AMS–FRL–6516–2]

RIN 2060–AI23

Control of Air Pollution From New

Motor Vehicles: Tier 2 Motor Vehicle

Emissions Standards and Gasoline

Sulfur Control Requirements

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Final rule.

SUMMARY: Today’s action finalizes a

major program designed to significantly

reduce the emissions from new

passenger cars and light trucks,

including pickup trucks, vans,

minivans, and sport-utility vehicles.

These reductions will provide for

cleaner air and greater public health

protection, primarily by reducing ozone

and PM pollution. The program is a

comprehensive regulatory initiative that

treats vehicles and fuels as a system,

combining requirements for much

cleaner vehicles with requirements for

much lower levels of sulfur in gasoline.

A list of major highlights of the program

appears at the beginning of the

SUPPLEMENTARY INFORMATION section of

this Federal Register.

The program we are finalizing today

will phase in a single set of tailpipe

emission standards that will, for the first

time, apply to all passenger cars, light

trucks, and larger passenger vehicles

operated on any fuel. This set of ‘‘Tier

2 standards’’ is feasible and the use of

a single set of standards is appropriate

because of the increased use of light

trucks for personal transportation. The

miles traveled in light trucks is

increasing and the emissions from these

vehicles are thus an increasing problem.

This approach builds on the recent

technology improvements resulting

from the successful National LowEmission Vehicles (NLEV) program.

To enable the very clean Tier 2

vehicle emission control technology to

be introduced and to maintain its

effectiveness, we are also requiring

reduced gasoline sulfur levels

nationwide. The reduction in sulfur

levels will also contribute directly to

cleaner air in addition to its beneficial

effects on vehicle emission control

systems. Refiners will generally install

additional refining equipment to remove

sulfur in their refining processes.

Importers of gasoline will be required to

import and market only gasoline

meeting the sulfur standards. Today’s

action also introduces an averaging,

banking, and trading program to provide

flexibility for refiners and ease

implementation of the gasoline sulfur

control program.

The overall program focuses on

reducing the passenger car and light

truck emissions most responsible for

causing ozone and particulate matter

problems. Without today’s action, we

project that emissions of nitrogen oxides

from these vehicles will represent as

much as 40 percent of this ozoneforming pollutant in some cities, and

almost 20 percent nationwide, by the

year 2030.

Today’s program will bring about

major reductions in annual emissions of

these pollutants and also reduce the

emissions of sulfur compounds

resulting from the sulfur in gasoline. For

example, we project a reduction in

oxides of nitrogen emissions of at least

856,000 tons per year by 2007 and

1,236,000 by 2010, the time frame when

many states will have to demonstrate

compliance with air quality standards.

Emission reductions will continue

increasing for many years, reaching at

least 2,220,000 tons per year in 2020

and continuing to rise further in future

years. In addition, the program will

reduce the contribution of vehicles to

other serious public health and

environmental problems, including

VOC, PM, and regional visibility

problems, toxic air pollutants, acid rain,

and nitrogen loading of estuaries.

Furthermore, we project that these

reductions, and their resulting

environmental benefits, will come at an

average cost increase of less than $100

per passenger car, an average cost

increase of less than $200 for light

trucks, and an average cost increase of

about $350 for medium-duty passenger

vehicles, and an average increase of less

than 2 cents per gallon of gasoline (or

about $120 over the life of an average

vehicle).

DATES: This rule is effective April 10,

2000.

The incorporation by reference of

certain publications contained in this

rule are approved by the Director of the

Federal Register as of April 10, 2000.

ADDRESSES: Comments: All comments

and materials relevant to today’s action

have been placed in Public Docket No.

A–97–10 at the following address: U.S.

Environmental Protection Agency

(EPA), Air Docket (6102), Room M–

1500, 401 M Street, S.W., Washington,

D.C. 20460. EPA’s Air Docket makes

materials related to this rulemaking

available for review at the above address

(on the ground floor in Waterside Mall)

from 8:00 a.m. to 5:30 p.m., Monday

through Friday, except on government

holidays. You can reach the Air Docket

by telephone at (202) 260–7548 and by

facsimile at (202) 260–4400. We may

charge a reasonable fee for copying

docket materials, as provided in 40 CFR

Part 2.

FOR FURTHER INFORMATION CONTACT:

Carol Connell, U.S. EPA, National

Vehicle and Fuels Emission Laboratory,

2000 Traverwood, Ann Arbor MI 48105;

Telephone (734) 214–4349, FAX (734)

214–4816, E-mail

connell.carol@epa.gov.

SUPPLEMENTARY INFORMATION:

Highlights of the Tier2/Gasoline Sulfur

Program

For cars, and light trucks, and larger

passenger vehicles, the program will—

• Starting in 2004, through a phasein, apply for the first time the same set

of emission standards covering

passenger cars, light trucks, and large

SUVs and passenger vehicles. These

emission levels (‘‘Tier 2 standards’’) are

feasible for these vehicles. The Tier 2

standards are also appropriate because

of the increased use of light trucks for

personal transportation—the miles

traveled in light trucks is increasing and

the emissions from these vehicles are

thus an increasing problem.

• Introduce a new category of

vehicles, ‘‘medium-duty passenger

vehicles,’’ thus bringing larger passenger

vans and SUVs into the Tier 2 program.

• During the phase-in, apply interim

fleet emission average standards that

match or are more stringent than current

federal and California ‘‘LEV I’’ (LowEmission Vehicle, Phase I) standards.

• Apply the same standards to

vehicles operated on any fuel.

• Allow auto manufacturers to

comply with the very stringent new

standards in a flexible way while

ensuring that the needed environmental

benefits occur.

• Build on the recent technology

improvements resulting from the

successful National Low-Emission

Vehicles (NLEV) program and improve

the performance of these vehicles

through lower sulfur gasoline.

• Set more stringent particulate

matter standards.

• Set more stringent evaporative

emission standards.

For commercial gasoline, the program

will—

• Significantly reduce average

gasoline sulfur levels nationwide as

early as 2000, fully phased in in 2006.

Refiners will generally add refining

equipment to remove sulfur in their

refining processes. Importers of gasoline

will be required to import and market

only gasoline meeting the sulfur limits.

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6699

• Provide for flexible implementation

by refiners through an averaging,

banking, and trading program.

• Encourage early introduction of

cleaner fuel into the marketplace

through an early sulfur credit and

allotment program.

• Apply temporary gasoline sulfur

standards to certain small refiners and

gasoline marketed in a limited

geographic area in the western U.S.

• Enable the new Tier 2 vehicles to

meet the emission standards by greatly

reducing the degradation of vehicle

emission control performance from

sulfur in gasoline. Lower sulfur gasoline

also appears to be necessary for the

introduction of advanced technologies

that promise higher fuel economy but

are very susceptible to sulfur poisoning

(for example, gasoline direct injection

engines).

• Reduce emissions from NLEV

vehicles and other vehicles already on

the road.

Regulated Entities

This action will affect you if you

produce new motor vehicles, alter

individual imported motor vehicles to

address U.S. regulation, or convert

motor vehicles to use alternative fuels.

It will also affect you if you produce,

distribute, or sell gasoline motor fuel.

The table below gives some examples

of entities that may have to comply with

the regulations. But because these are

only examples, you should carefully

examine these and existing regulations

in 40 CFR parts 80 and 86. If you have

questions, call the person listed in the

FOR FURTHER INFORMATION CONTACT

section above.

Category NAICS codes a SIC Codes b Examples of potentially regulated entities

Industry ......................................................................... 336111 3711 Motor Vehicle Manufacturers.

336112

336120

Industry ......................................................................... 336311 3592 Alternative fuel vehicle converters.

336312 3714

422720 5172

454312 5984

811198 7549

541514 8742

541690 8931

Industry ......................................................................... 811112 7533 Commercial Importers of Vehicles and Vehicle Components.

811198 7549

541514 8742

Industry ......................................................................... 324110 2911 Petroleum Refiners.

Industry ......................................................................... 422710 5171 Gasoline Marketers and Distributors.

422720 5172

Industry ......................................................................... 484220 4212 Gasoline Carriers.

484230 4213

a North American Industry Classification System (NAICS).

bStandard Industrial Classification (SIC) system code.

Access to Rulemaking Documents

Through the Internet

Today’s action is available

electronically on the day of publication

from the Office of the Federal Register

Internet Web site listed below.

Electronic copies of this preamble and

regulatory language as well as the

Response to Comments document, the

Regulatory Impact Analysis and other

documents associated with today’s final

rule are available from the EPA Office

of Mobile Sources Web site listed below

shortly after the rule is signed by the

Administrator. This service is free of

charge, except any cost that you already

incur for connecting to the Internet.

Federal Register Web Site: http://

www.epa.gov/docs/fedrgstr/epa-air/

(Either select a desired date or use the

Search feature.)

Office of Mobile Sources (OMS) Web

Site: http://www.epa.gov/oms/ (Look

in ‘‘What’s New’’ or under the

‘‘Automobiles’’ topic.)

Please note that due to differences

between the software used to develop

the document and the software into

which the document may be

downloaded, changes in format, page

length, etc., may occur.

Outline of This Preamble

I. Introduction

A. What Are the Basic Components of the

Program?

1. Vehicle Emission Standards

2. Gasoline Sulfur Standards

B. What Is Our Statutory Authority for

Today’s Action?

1. Light-Duty Vehicles and Trucks

2. Gasoline Sulfur Controls

C. The Tier 2 Study and the Sulfur Staff

Paper

D. Relationship of Diesel Fuel Sulfur

Control to the Tier 2/Gasoline Sulfur

Program

II. Tier 2 Determination

A. There Is a Substantial Need for Further

Emission Reductions in Order To Attain

and Maintain National Ambient Air

Quality Standards

B. More Stringent Standards for Light-Duty

Vehicles and Trucks Are Technologically

Feasible

C. More Stringent Standards for Light-Duty

Vehicles and Trucks Are Needed and

Cost Effective Compared to Available

Alternatives

III. Air Quality Need For and Impact of

Today’s Action

A. Americans Face Serious Air Quality

Problems That Require Further Emission

Reductions

B. Ozone

1. Background on Ozone Air Quality

2. Additional Emission Reductions Are

Needed To Attain and Maintain the

Ozone NAAQS.

a. Summary

b. Ozone Modeling Presented in Our

Proposal and Supplemental Notice

c. Updated and Additional Ozone

Modeling

d. Results and Conclusions

e. Issues and Comments Addressed

f. 8-Hour Ozone

3. Cars and Light-Duty Trucks Are a Big

Part of the NOX and VOC Emissions, and

Today’s Action Will Reduce This

Contribution Substantially

4. Ozone Reductions Expected From This

Rule

C. Particulate Matter

1. Background on PM

2. Need for Additional Reductions to

Attain and Maintain the PM10 NAAQS

3. PM25 Discussion

4. Emission Reductions and Ambient PM

Reductions

D. Other Criteria Pollutants: Carbon

Monoxide, Nitrogen Dioxide, Sulfur

Dioxide

E. Visibility

6700 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

F. Air Toxics

G. Acid Deposition

H. Eutrophication/Nitrification

I. Cleaner Cars and Light Trucks Are

Critically Important to Improving Air

Quality

IV. What Are the New Requirements for

Vehicles and Gasoline?

A. Why Are We Proposing Vehicle and

Fuel Standards Together?

1. Feasibility of Stringent Standards for

Light-Duty Vehicles and Light-Duty

Trucks a. Gasoline Fueled Vehicles i.

LDVs and LDT1s–LDT4s ii. MediumDuty Passenger Vehicles (MDPVs) b.

Diesel Vehicles

2. Gasoline Sulfur Control Is Needed To

Support the Proposed Vehicle Standards

a. How Does Gasoline Sulfur Affect

Vehicle Emission Performance? b. How

Large Is Gasoline Sulfur’s Effect on

Emissions? c. Sulfur’s Negative Impact

on Tier 2 Catalysts d. Sulfur Has

Negative Impacts on OBD Systems

B. Our Program for Vehicles

1. Overview of the Vehicle Program a.

Introduction b. Corporate Average NOx

Standard c. Tier 2 Exhaust Emission

Standard ‘‘Bins’ d. Schedules for

Implementation i. Implementation

Schedule for Tier 2 LDVs and LLDTs ii.

Implementation Schedule for Tier 2

HLDTs e. Interim Standards i. Interim

Exhaust Emission Standards for LDV/

LLDTs ii Interim Exhaust Emission

Standards for HLDTs iii. Interim

Programs Will Provide Reductions Over

Previous Standards f. Generating,

Banking, and Trading NOx Credits

2. Why Are We Finalizing the Same Set of

Standards for Tier 2 LDVs and LDTs?

3. Why Are We Finalizing the Same

Standards for Both Gasoline and Diesel

Vehicles?

4. Key Elements of the Vehicle Program a.

Basic Exhaust Emission Standards and

‘‘Bin’’ Structure i. Why Are We

Including Extra Bins? b. The Program

Will Phase In the Tier 2 Vehicle

Standards Over Several Years i. Primary

Phase-in Schedule

ii. Alternative Phase-in Schedule

c. Manufacturers Will Meet a ‘‘Corporate

Average’’ NOX Standard

d. Manufacturers Can Generate, Bank, and

Trade NOX Credits

i. General Provisions

ii. Averaging, Banking and Trading of NOX

Credits Fulfills Several Goals

iii. How Manufacturers Can Generate and

Use NOX Credits

iv. Manufacturers Can Earn and Bank

Credits for Early NOX Reductions

v. Tier 2 NOX Credits Will Have Unlimited

Life

vi. NOX Credit Deficits Can Be Carried

Forward

vii. Encouraging the Introduction of Ultra

Clean Vehicles

e. Interim Standards

i. Interim Exhaust Emission Standards for

LDV/LLDTs

ii. Interim Exhaust Emission Standards for

HLDTs

f. Light-Duty Evaporative Emission

Standards

g. Passenger Vehicles Above 8,500 Pounds

GVWR

C. Our Program for Controlling Gasoline

Sulfur

1. Gasoline Sulfur Standards for Refiners

and Importers

a. Standards and Deadlines That Refiners/

Importers Must Meet

i. What Are the Per-Gallon Caps on

Gasoline Sulfur Levels in 2004 and

Beyond?

ii. What Standards Must Refiners/

Importers Meet on a Corporate Average

Basis?

iii. What Standards Must Be Met by

Individual Refineries/Importers?

b. Standards and Deadlines for Refiners/

Importers Which Provide Gasoline to the

Geographic Phase-in Area (GPA)

i. Justification for Our Geographic Phase-in

Approach

ii. What Is the Geographic Phase-in Area

and How Was It Established?

iii. Standards/Deadlines for Gasoline Sold

in the Geographic Phase-in Area

iv. What Are the Per-Gallon Caps on

Gasoline Sulfur Levels in the Phase-in

Area?

v. How Do Refiners/Importers Account for

GPA Fuel in Their Corporate Average

Calculations?

vi. How Do Refiners/Importers Apply for

the Geographic Phase-in Area Standards?

vii. How Will EPA Establish the GPA in

Adjacent States?

c. How Does the Sulfur Averaging,

Banking, and Trading Program Work?

i. Generating Allotments Prior to 2004

ii. Generating Allotments in 2004 and 2005

iii. Using Allotments in 2004 and 2005

iv. How Long Do Allotments Last?

v. Establishing Individual Refinery Sulfur

Baselines for Credit Generation Purposes

vi. Generating Sulfur Credits Prior to 2004

vii. Generating Sulfur Credits in 2004 and

Beyond

viii. Using Sulfur Credits

ix. How Long Do Credits Last?

x. Conversion of Allotments Into Credits

d. How are State Sulfur Programs Affected

by EPA’s Program?

2. Hardship Provision for Qualifying

Refiners

a. Hardship Provision for Qualifying Small

Refiners

i. How Are Small Refiners Defined?

ii. Standards That Small Refiners Must

Meet

iii. How Do Small Refiners Apply for Small

Refiner Status?

iv. How Do Small Refineries Apply for a

Sulfur Baseline?

v. Volume Limitation on Use of a Small

Refinery Standard

vi. Extensions Beyond 2007 for Small

Refiners

vii. Can Small Refiners Participate in the

ABT Program?

b. Temporary Waivers From Low Sulfur

Requirements in Extreme Unforeseen

Circumstances

c. Temporary Waivers Based on Extreme

Hardship Circumstances

3. Streamlining of Refinery Air Pollution

Permitting Process

a. Brief Summary of Proposal

b. Significant Comments Received

c. Today’s Action

i. Major New Source Review

ii. Environmental Justice

D. What Are the Economic Impacts, Cost

Effectiveness and Monetized Benefits of

the Tier 2 Program?

1. What Are the Estimated Costs of the

Vehicle Standards?

2. Estimated Costs of the Gasoline Sulfur

Standards

3. What Are the Aggregate Costs of the Tier

2/Gasoline Sulfur Final Rule?

4. How Does the Cost-Effectiveness of This

Program Compare to Other Programs?

a. Cost Effectiveness of this Program

b. How Does the Cost Effectiveness of This

Program Compare With Other Means of

Obtaining Mobile Source NOX+NMHC

Reductions?

c. How Does the Cost Effectiveness of This

Program Compare With Other Known

Non-Mobile Source Technologies for

Reducing NOX+NMHC?

5. Does the Value of the Benefits Outweigh

the Cost of the Standards?

a. What Is the Purpose of This Benefit-Cost

Comparison?

b. What Was Our Overall Approach to the

Benefit-Cost Analysis?

c. What Are the Significant Limitations of

the Benefit-Cost Analysis?

d. How Was the Benefit-Cost Analysis

Changed From Proposal?

e. How Did We Perform the Benefit-Cost

Analysis?

f. What Were the Results of the BenefitCost Analysis?

V. Other Vehicle-Related Provisions

A. Final Tier 2 CO, HCHO and PM

Standards

1. Carbon Monoxide (CO) Standards

2. Formaldehyde (HCHO) Standards

3. Use of NMHC Data To Show Compliance

With NMOG Standards; Alternate

Compliance With Formaldehyde

Standards.

4. Particulate Matter (PM) Standards

B. Useful Life

1. Mandatory 120,000 Mile Useful Life

2. 150,000 Mile Useful Life Certification

Option

C. Supplemental Federal Test Procedure

(SFTP) Standards

1. Background

2. SFTP Under the NLEV Program

3. SFTP Standards for the Interim and Tier

2 LDVs and LDTs: As Proposed

4. Final SFTP Standards for Interim and

Tier 2 LDVs and LDTs

5. Adding a PM Standard to the SFTP

Standards

6. Future Efforts Relevant to SFTP

Standards

D. LDT Test Weight

E. Test Fuels

F. Changes to Evaporative Certification

Procedures to Address Impacts of

Alcohol Fuels

G. Other Test Procedure Issues

H. Small Volume Manufacturers

1. Special Provisions for Independent

Commercial Importers (ICIs)

2. Hardship Provision for Small Volume

Manufacturers

I. Compliance Monitoring and Enforcement

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6701

1. Application of EPA’s Compliance

Assurance Program, CAP2000

2. Compliance Monitoring

3. Relaxed In-Use Standards for Vehicles

Produced During the Phase-in Period

4. Enforcement of the Tier 2 and Interim

Corporate Average NOX Standards.

J. Addressing Environmentally Beneficial

Technologies Not Recognized by Test

Procedures

K. Adverse Effects of System Leaks

L. The Future Development of Advanced

Technology and the Role of Fuels

M. Miscellaneous Provisions

VI. Gasoline Sulfur Program Compliance

and Enforcement Provisions

A. Overview

B. Requirements for Foreign Refiners and

Importers

1. Requirements for Foreign Refiners With

Individual Refinery Sulfur Standards or

Credit Generation Baselines

2. Requirements for Truck Importers

C. What Standards and Requirements

Apply Downstream?

D. Testing and Sampling Methods and

Requirements

1. Test Method for Sulfur in Gasoline

2. Test Method for Sulfur in Butane

3. Quality Assurance Testing

4. Requirement to Test Every Batch of

Gasoline Produced or Imported

5. Exceptions to the Every-Batch Testing

Requirement

6. Sampling Methods

7. Gasoline Sample Retention

Requirements

E. Federal Enforcement Provisions for

California Gasoline and for Use of

California Test Methods to Determine

Compliance

F. Recordkeeping and Reporting

Requirements

1. Product Transfer Documents

2. Recordkeeping Requirements

3. Reporting Requirements

G. Exemptions for Research, Development,

and Testing

H. Liability and Penalty Provisions for

Noncompliance

I. How Will Compliance With the Sulfur

Standards Be Determined?

VII. Public Participation

VIII. Administrative Requirements

A. Administrative Designation and

Regulatory Analysis

B. Regulatory Flexibility

1. Potentially Affected Small Businesses

2. Small Business Advocacy Review Panel

and the Evaluation of Regulatory

Alternatives

C. Paperwork Reduction Act

D. Intergovernmental Relations

1. Unfunded Mandates Reform Act

2. Executive Order 13084: Consultation

and Coordination With Indian Tribal

Governments

3. Executive Order 13132 (Federalism)

E. National Technology Transfer and

Advancement Act

F. Executive Order 13045: Children’s

Health Protection

G. Congressional Review Act

IX. Statutory Provisions and Legal Authority

I. Introduction

Since the passage of the 1990 Clean

Air Act Amendments, the U.S. has made

significant progress in reducing

emissions from passenger cars and light

trucks. The National Low-Emission

Vehicle (NLEV) and Reformulated

Gasoline (RFG) programs are important

examples of control programs that are in

place and will continue to help reduce

car and light-duty truck emissions into

the near future.

Nonetheless, due to increasing vehicle

population and vehicle miles traveled,

passenger cars and light trucks will

continue to be significant contributors

to air pollution inventories well into the

future. In fact, the emission contribution

of light trucks and sport utility vehicles

now matches that of passenger cars.

(This is occurring because of the

combination of growth in miles traveled

by light trucks and the fact that their

emission standards are currently less

stringent than those of passenger cars).

The program we describe below builds

on the NLEV and RFG Phase II programs

to develop a strong new national

program to protect public health and the

environment well into the next century.

The program, while reducing VOC and

other emissions, focuses especially on

NOX, because that is where the largest

air quality gains can be achieved.

We have followed several overarching

principles in developing this final rule:

• Design a strong national program

that will assist states in every region of

the country to meet their air quality

objectives and that will ensure that cars

and trucks continue to contribute a fair

share to our nation’s overall air quality

solutions;

• View vehicles and fuels as an

integrated system, recognizing that only

by addressing both can the best overall

emission performance be achieved;

• Establish a single set of emission

standards that apply regardless of the

fuel used and whether the vehicle is a

car, a light truck, or a larger passenger

vehicle;

• Provide compliance flexibilities

that allow vehicle manufacturers and oil

refiners to adjust to future market trends

and honor consumer preferences;

• Not preclude the development of

advanced low emission or fuel efficient

technologies such as lean-burn engines;

and

• Ensure sufficient leadtime for

phase-in of the Tier 2 and gasoline

sulfur program.

With these principles as background,

we turn now to an overview of the

vehicle and fuel aspects of the program.

Sections I and II of this preamble will

give you a brief overview of our program

and our rationale for implementing it.

Subsequent sections will expand on the

air quality need, technological

feasibility, economic impacts, and

provide a detailed description of the

specifics of the program. A public

participation section reviews the

process we followed in soliciting and

responding to public comment. The

final sections deal with several

administrative requirements. You may

also want to review our Final Regulatory

Impact Analysis (RIA) and our Response

to Comments document, both of which

are found in the docket and on the

Internet. They provide additional

analyses and discussions of many topics

raised in this preamble.

A. What Are the Basic Components of

the Program?

The nation’s air quality, while

certainly better than in the past, will

nevertheless continue to expose tens of

millions of Americans to unhealthy

levels of air pollution well into the

future in the absence of significant new

controls on emissions from motor

vehicles. EPA is therefore finalizing a

major, comprehensive program designed

to reduce emission standards for

passenger cars, light trucks, and large

passenger vehicles (including sportutility vehicles, minivans, vans, and

pickup trucks) and to reduce the sulfur

content of gasoline. Under the program,

automakers will produce vehicles

designed to have very low emissions

when operated on low-sulfur gasoline,

and oil refiners will provide that much

cleaner gasoline nationwide. In this

preamble, we refer to the

comprehensive program as the ‘‘Tier 2/

Gasoline Sulfur program.’’

1. Vehicle Emission Standards

Today’s action sets new federal

emission standards (‘‘Tier 2 standards’’)

for passenger cars, light trucks, and

larger passenger vehicles. The program

is designed to focus on reducing the

emissions most responsible for the

ozone and particulate matter (PM)

impact from these vehicles—nitrogen

oxides (NOX) and non-methane organic

gases (NMOG), consisting primarily of

hydrocarbons (HC) and contributing to

ambient volatile organic compounds

(VOC). The program will also, for the

first time, apply the same set of federal

standards to all passenger cars, light

trucks, and medium-duty passenger

vehicles. Light trucks include ‘‘light

light-duty trucks’’ (or LLDTs), rated at

less than 6000 pounds gross vehicle

weight and ‘‘heavy light-duty trucks’’

(or HLDTs), rated at more than 6000

6702 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

1A vehicle’s ‘‘Gross Vehicle Weight Rating,’’ or

GVWR, is the curb weight of the vehicle plus its

maximum recommended load of passengers and

cargo.

2By comparison, the NOX standards for the

National Low Emission Vehicle (NLEV) program,

which will be in place nationally in 2001, range

from 0.30 g/mi for passenger cars to 0.50 g/mi for

medium-sized light trucks (larger light trucks are

not covered). For further comparison, the standards

met by today’s Tier 1 vehicles range from 0.60 g/

mi to 1.53 g/mi.

3There are also NMOG standards associated with

both the interim and Tier 2 standards. The NMOG

standards vary depending on which of various

individual sets of emission standards manufacturers

choose to use in complying with the average NOX

standard. This ‘‘bin’’ approach is described more

fully in section IV.B. of this preamble.

4LDTs with a loaded vehicle weight less than or

equal to 3750 pounds, called LDT1s and LDT2s.

5Section 202(b)(1)(C) forbids EPA from

promulgating mandatory standards more stringent

than Tier 1 standards until the 2004 model year.

pounds gross vehicle weight).1

‘‘Medium-duty passenger vehicles’’ (or

MDPVs) form a new class of vehicles

introduced by this rule that includes

SUVs and passenger vans rated at

between 8,500 and 10,000 GVWR. The

program thus ensures that essentially all

vehicles designed for passenger use in

the future will be very clean vehicles.

The Tier 2 standards finalized today

will reduce new vehicle NOX levels to

an average of 0.07 grams per mile (g/mi).

For new passenger cars and light LDTs,

these standards will phase in beginning

in 2004, with the standards to be fully

phased in by 2007.2 For heavy LDTs and

MDPVs, the Tier 2 standards will be

phased in beginning in 2008, with full

compliance in 2009.

During the phase-in period from

2004–2007, all passenger cars and light

LDTs not certified to the primary Tier 2

standards will have to meet an interim

average standard of 0.30 g/mi NOX,

equivalent to the current NLEV

standards for LDVs and more stringent

than NLEV for LDT2s (e.g., minivans).3

During the period 2004–2008, heavy

LDTs and MDPVs not certified to the

final Tier 2 standards will phase in to

an interim program with an average

standard of 0.20 g/mi NOX, with those

not covered by the phase-in meeting a

per-vehicle standard (i.e., an emissions

‘‘cap’’) of 0.6 g/mi NOX (for HLDTs) and

0.9 g/mi NOX (for MDPVs). The average

standards for NOX will allow

manufacturers to comply with the very

stringent new standards in a flexible

way, assuring that the average emissions

of a company’s production meet the

target emission levels while allowing

the manufacturer to choose from several

more- and less-stringent emission

categories for certification.

We are also setting stringent

particulate matter standards that will be

especially important if there is

substantial future growth in the sales of

diesel vehicles. Before 2004, we are

establishing more stringent interim PM

standards for most light trucks than

exist now under NLEV. With higher

sales of diesel cars and light trucks, they

could easily contribute between onehalf and two percent of the PM10

concentration allowed by the NAAQS,

with some possibility that the

contribution could be as high as 5 to 40

percent in some roadside situations

with heavy traffic. These increases

would make attainment even more

difficult for 8 counties which we

already predict to need further emission

reductions even without an increase in

diesel sales, and would put at risk

another 18 counties which are now

within 10 percent of a NAAQS

violation. Thus, by including a more

stringent PM standard in the program

finalized today, we help address

environmental concerns about the

potential growth in the numbers of

light-duty diesels on the road—even if

that growth is substantial. The new

requirements also include more

stringent hydrocarbon controls (exhaust

NMOG and evaporative emissions

standards). We will also monitor the

progress of the development of

advanced technologies and the role of

fuels.

2. Gasoline Sulfur Standards

The other major part of today’s action

will significantly reduce average

gasoline sulfur levels nationwide. We

expect these reductions could begin to

phase in as early as 2000, with full

compliance for most refiners occurring

by 2006. Refiners will generally install

advanced refining equipment to remove

sulfur during the production of gasoline.

Importers of gasoline will be required to

import and market only gasoline

meeting the sulfur limits. Temporary,

less stringent standards will apply to a

few small refiners through 2007. In

addition, temporary, less stringent

standards will apply to a limited

geographic area in the western U.S. for

the 2004–2006 period.

This significant new control of

gasoline sulfur content will have two

important effects. The lower sulfur

levels will enable the much-improved

emission control technology necessary

to meet the stringent vehicle standards

of today’s rule to operate effectively

over the useful life of the new vehicles.

In addition, as soon as the lower sulfur

gasoline is available, all gasoline

vehicles already on the road will have

reduced emissions—from less

degradation of their catalytic converters

and from fewer sulfur compounds in the

exhaust.

Today’s action will encourage refiners

to reduce sulfur in gasoline as early as

2000. The program requires that most

refiners and importers meet a corporate

average gasoline sulfur standard of 120

ppm and a cap of 300 ppm beginning in

2004. By 2006, the cap will be reduced

to 80 ppm and most refineries must

produce gasoline averaging no more

than 30 ppm sulfur. The program builds

upon the existing regulations covering

gasoline composition as it relates to

emissions performance. It includes

provisions for trading of sulfur credits,

increasing the flexibility available to

refiners for complying with the new

requirements. We intend for the credit

program to ease compliance

uncertainties by providing refiners the

flexibility to phase in early controls in

2000–2003 and use credits gained in

these years to delay some control until

as late as 2006. As finalized today, the

program will achieve the needed

environmental benefits while providing

substantial flexibility to refiners.

B. What Is Our Statutory Authority for

Today’s Action?

1. Light-Duty Vehicles and Trucks

We are setting motor vehicle emission

standards under the authority of section

202 of the Clean Air Act. Sections 202(a)

and (b) of the Act provide EPA with

general authority to prescribe vehicle

standards, subject to any specific

limitations otherwise included in the

Act. Sections 202(g) and (h) specify the

current standards for LDVs and LDTs,

which became effective beginning in

model year 1994 (‘‘Tier 1 standards’’).

Section 202(i) of the Act provides

specific procedures that EPA must

follow to determine whether standards

more stringent than Tier 1 standards for

LDVs and certain LDTs 4 are appropriate

beginning between the 2004 and 2006

model years.5 Specifically, we are

required to first issue a study regarding

‘‘whether or not further reductions in

emissions from light-duty vehicles and

light-duty trucks should be required

* * *’’ (the ‘‘Tier 2 Study’’). This study

‘‘shall examine the need for further

reductions in emissions in order to

attain or maintain the national ambient

air quality standards.’’ It is also to

consider: (1) The availability of

technology to meet more stringent

standards, taking cost, lead time, safety,

and energy impacts into consideration;

and (2) the need for, and cost

effectiveness of, such standards,

including consideration of alternative

methods of attaining or maintaining the

national ambient air quality standards.

A certain set of ‘‘default’’ emission

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6703

6LDTs that have gross vehicle weight ratings

above 6000 pounds are considered ‘‘heavy-duty

vehicles’’ under the Act. See section 202(b)(3). For

regulatory purposes, we refer to these LDTs as

‘‘heavy light-duty trucks’’ made up of LDT3s and

LDT4s. 7We currently have regulatory requirements for

conventional and reformulated gasoline adopted

under Sections 211(c) and 211(k) of the Act, in

addition to the ‘‘substantially similar’’ requirements

for fuel additives of Section 211(f). These

requirements have the effect of limiting sulfur

levels in gasoline to some extent. See the Final RIA

for more details.

8On April 28, 1998, EPA published a notice of

availability announcing the release of a draft of the

Tier 2 study and requesting comments on the draft.

The final report to Congress included a summary

and analysis of the comments EPA received.

standards for these vehicle classes is

among those options for new standards

that EPA is to consider.

After the study is completed and the

results are reported to Congress, EPA is

required to determine by rulemaking

whether: (1) There is a need for further

emission reductions; (2) the technology

for more stringent emission standards

from the affected classes is available;

and (3) such standards are needed and

cost-effective, taking into account

alternatives. If EPA answers ‘‘yes’’ to

these questions, then the Agency is to

promulgate new, more stringent motor

vehicle standards (‘‘Tier 2 standards’’).

EPA submitted its report to Congress

on July 31, 1998. Today’s final rule

makes affirmative responses to the three

questions above (see Section II below)

and sets new standards that are more

stringent than the default standards in

the Act.

EPA is also setting standards for larger

light-duty trucks and MDPVs under the

general authority of Section 202(a)(1)

and 202(b) and under Section 202(a)(3)

of the Act, which requires that

standards applicable to emissions of

hydrocarbons, NOX, CO and PM from

heavy-duty vehicles 6 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.

We are also setting standards for

formaldehyde under our authority in

sections 202(a) and (l).

2. Gasoline Sulfur Controls

We are adopting gasoline sulfur

controls pursuant to our authority under

Section 211(c)(1) of the Clean Air Act.7

Under Section 211(c)(1), EPA may adopt

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

significantly impair emissions control

systems in general use or which will be

in general use were the fuel control to

be adopted.

We are adopting gasoline sulfur

controls based on both of these criteria.

Under the first criterion, we believe that

sulfur in gasoline used in Tier 1 and

LEV technology vehicles contributes to

ozone pollution, air toxics, and PM.

Under the second criterion, we believe

that gasoline sulfur in fuel will

significantly impair the emissions

control systems expected to be used in

Tier 2 technology vehicles, as well as

emissions control systems currently

used in LEVs. Please refer to Section

IV.C. below and to the Final Regulatory

Impact Analysis (RIA) for more details

of our analysis and findings. The RIA

includes a more detailed discussion of

EPA’s authority to set gasoline sulfur

standards, including a discussion of our

conclusions relating to the factors

required to be considered under Section

211(c).

C. The Tier 2 Study and the Sulfur Staff

Paper

On July 31, 1998, EPA submitted its

report to Congress containing the results

of the Tier 2 study.8 The study indicated

that in the 2004 and later time frame,

there will be a need for emission

reductions to aid in meeting and

maintaining the National Ambient Air

Quality Standards (NAAQS) for both

ozone and PM. Air quality modeling

showed that in the 2007–2010 time

frame, when Tier 2 standards will

become fully effective, a number of

areas will still be in nonattainment for

ozone and PM even after the

implementation of existing emission

controls. The study also noted the

continued existence of carbon monoxide

(CO) nonattainment areas. It also found

ample evidence that technologies will

be available to meet more stringent Tier

2 standards. In addition, the study

provided evidence that such standards

could be implemented at a similar cost

per ton of reduced pollutants as other

programs aimed at similar air quality

problems. Finally, the study identified

several additional issues in need of

further examination, including the

relative stringency of car and light truck

emission standards, the appropriateness

of identical versus separate standards

for gasoline and diesel vehicles, and the

effects of sulfur in gasoline on catalyst

efficiency. Section IV of this preamble

describes the steps we have taken to

follow up on the Tier 2 Study.

In addition, on May 1, 1998, EPA

released a staff paper presenting EPA’s

understanding of the impact of gasoline

sulfur on emissions from motor vehicles

and exploring what gasoline producers

and automobile manufacturers could do

to reduce sulfur’s impact on emissions.

The staff paper noted that gasoline

sulfur degrades the effectiveness of

catalytic converters and that high sulfur

levels in commercial gasoline could

affect the ability of future automobiles—

especially those designed for very low

emissions—to meet more stringent

standards in use. It also pointed out that

sulfur control will provide additional

benefits by lowering emissions from the

current fleet of vehicles.

D. Relationship of Diesel Fuel Sulfur

Control to the Tier 2/Gasoline Sulfur

Program

In the NPRM, we raised the question

of what if any changes to diesel fuel

may be needed to enable diesel vehicles

to meet the Tier 2 standards or any

future heavy-duty diesel engine

standards. Specifically, we raised the

question of whether diesel sulfur levels

need to be controlled. Since diesel fuel

controls of any kind would have an

impact on the refinery as a whole, and

since in some cases (including potential

diesel sulfur limits) could have

implications for gasoline sulfur control,

we requested comment on this issue in

our proposal. We also indicated that we

planned to release an Advance Notice of

Proposed Rulemaking to solicit more

information on this subject.

We published the ANPRM on May 13,

1999 (64 FR 26142). We are in the

process of considering all of the

comments received in response to the

ANPRM and plan to issue a Notice of

Proposed Rulemaking (NPRM) in early

spring of 2000. We received many

comments on the subject of diesel fuel

control along with the comments

submitted on the proposed Tier 2/

Gasoline Sulfur regulations. We have

prepared brief responses to some of

these comments in the Response to

Comments document, and will deal

fully with these comments as part of the

forthcoming NPRM on diesel fuel. We

are taking no action on diesel fuel as

part of today’s action.

II. Tier 2 Determination

Based on the statutory requirements

described above and the evidence

provided in the Tier 2 Study and since

its release, as described elsewhere in

this preamble, EPA has determined that

new, more stringent emission standards

are indeed needed, technologically

feasible, and cost effective.

6704 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

9The Final RIA contains a more detailed analysis,

and Section IV.A. below has further discussion of

the technological feasibility of our standards

including detailed discussions of the various

technology options that we believe manufacturers

may use to meet these standards.

A. There Is a Substantial Need for

Further Emission Reductions in Order to

Attain and Maintain National Ambient

Air Quality Standards

EPA finds that there is a clear air

quality need for new emission

standards, based on the continuing air

quality problems predicted to exist in

future years. As the discussion in

Section III.B. illustrates, 26 metropolitan

areas are each certain or highly likely to

need additional reductions. These areas

are distributed across most regions of

the U.S., and have a combined

population of over 86 million. Section

III.B. also shows that an additional 12

areas each has a moderate to significant

probability of needing additional

reductions, representing another 25

million people. This provides ample

evidence that further emission

reductions are needed to meet the 1-

hour ozone NAAQS.

In addition to these ozone concerns,

our analysis of PM10 monitoring data

and PM10 projections indicates that 15

PM10 nonattainment counties violated

the PM10 NAAQS in recent years, and

that 8 of them with a 1996 population

of almost 8 million have a high risk of

failing to attain and maintain without

more emission reductions. Eighteen

other counties, with a population of 23

million have a significant risk of failing

or are within 10 percent of violating the

PM10 NAAQS. It is also important to

recognize that nonattainment areas

remain for other criteria pollutants (e.g.,

CO) and that non-criteria pollution (e.g.,

air toxics and regional haze) also

contributes to environmental and health

concerns.

B. More Stringent Standards for LightDuty Vehicles and Trucks Are

Technologically Feasible

We find that emission standards

significantly more stringent than current

Tier 1 and National Low Emission

Vehicle (NLEV) levels are

technologically feasible. This is true

both for the LDVs and LDTs specifically

covered in section 202(i) and for the

medium-duty passenger vehicles also

included in today’s final rule.

Manufacturers are currently producing

NLEV vehicles that meet more stringent

standards than similar Tier 1 models.

Our analysis shows that mainly through

improvements in engine control

software and catalytic converter

technology, manufacturers can build

and are building durable vehicles and

trucks, including heavy light-duty

trucks, which have very low emission

levels.9 Section IV.A. below discusses

our feasibility conclusions in more

detail.

Many current production vehicles are

already certified at or near the Tier 2

standards. For year 2000 certification

(although not yet complete), over 50

vehicle models have emissions at or

below Tier 2 levels. In addition, we

performed a demonstration program at

our EPA laboratory that showed that

even large vehicles, which would be

expected to face the toughest challenges

reaching Tier 2 emission levels, can do

so with conventional technology.

Others, including the Manufacturers of

Emission Controls Association (MECA)

and the State of California, have also

performed demonstration programs,

with similar results. Manufacturers have

also certified LDVs and LDTs to NMOG

and CO levels as much as 80 percent

below Tier 1 standards. Furthermore, for

passenger vehicles greater than 8500 lbs

GVWR, we believe that by using

technologies and control strategies

similar to what will be used on lighter

vehicles, manufacturers will be able to

meet the Tier 2 emission standards.

Thus, we believe that, by the 2004–

2009 time frame, manufacturers will be

fully able to comply with the new Tier

2 emission standard levels. In addition,

to facilitate manufacturers’ efforts to

meet these new standards, the Tier 2

regulations include a phase-in over

several years and a corporate fleet

average NOX standard, which will allow

manufacturers to optimize the

deployment of technology across their

product lines with no loss of

environmental benefit. Our analysis of

the available technology improvements

and the very low emission levels

already being realized on these vehicles

leads us to find that the standards

adopted today are fully feasible for

LDVs and LDTs.

C. More Stringent Standards for LightDuty Vehicles and Trucks Are Needed

and Cost Effective Compared to

Available Alternatives

In this action, we also find that more

stringent motor vehicle standards are

both necessary and cost effective. As

discussed above, substantial further

reductions in emissions are needed to

help reduce the levels of unhealthy air

pollution to which millions of people

are being exposed; in particular, we

expect that a number of areas will not

attain or maintain compliance with the

National Ambient Air Quality Standards

for ozone and PM10 without such

reductions. (We describe this further in

Section III below and in the RIA.)

Furthermore, mobile sources are

important contributors to the air quality

problem. As we will explain more fully

later in this preamble, in the year 2030,

the cars and light trucks that are the

subject of today’s final rule are projected

to contribute as much as 40 percent of

the total NOX inventory in some cities,

and almost 20 percent of nationwide

NOX emissions. This situation would

have been considerably worse without

the NLEV program created by vehicle

manufacturers, EPA, the Northeastern

states, and others.

These emission reductions are clearly

necessary to meet and maintain the 1-

hour ozone NAAQS. We project that

while the emission reductions of this

program will lead to substantial

progress in meeting and maintaining the

NAAQS, many areas will still not come

into attainment even with this

magnitude of reductions.

We find that the Tier 2/Gasoline

Sulfur program is a reasonable, costeffective method of providing

substantial progress towards attainment

and maintenance of the NAAQS, costing

about $2000 per ton of NOX plus

hydrocarbon emissions reduced. This

program will reduce annual NOX

emissions by about 2.2 million tons per

year in 2020 and 2.8 million tons per

year in 2030 after the program is fully

implemented. By way of comparison,

when EPA established its 8-hour

NAAQS for ozone, we identified several

types of emission control programs that

were reasonably cost effective. If all of

the controls identified in that analysis

costing less than $10,000/ton were

implemented nationwide, they would

produce NOX emission reductions of

about 2.9 million tons per year. (That is,

to achieve about the same emission

reductions as the Tier 2/Gasoline Sulfur

program, other alternative measures

would have a significantly higher cost

per ton). These emission reductions are

clearly necessary to meet and maintain

the one-hour ozone NAAQS. We project

that while the emission reductions of

this program will lead to substantial

progress in meeting and maintaining the

NAAQS, many areas will still not come

into attainment even with this

magnitude of reductions.

In addition, the magnitude of

emission reductions that can be

achieved by a comprehensive national

Tier 2/Gasoline Sulfur program will be

difficult to achieve from any other

source category. Given the large

contribution that light-duty mobile

source emissions make to the national

emissions inventory and the range of

control programs ozone-affected areas

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6705

10National Air Quality and Emissions Trend

Report, 1997, Air Quality Trends Analysis Group,

Office of Air Quality Planning and Standards, U.S.

Environmental Protection Agency, Research

Triangle Park, N.C., December 1998 (available on

the World Wide Web at http://www/epa.gov/oar/

aqtrnd97/). 11U.S. Environmental Protection Agency, Latest

Findings on National Air Quality: 1997 Status and

Trends. December 1998.

already have in place or would be

expected to implement, we believe it

will be very difficult, if not impossible,

to meet (and maintain) the ozone

NAAQS in a cost-effective manner

without large emission reductions from

LDVs and LDTs. We expect emissions

from MDPVs to also play an increasing

role.

Furthermore, we project that the Tier

2/Gasoline Sulfur program will

significantly reduce direct and

secondary particulate matter coming

from LDVs, LDTs, and MDPVs—by

about 36,000 tons per year of direct PM

alone by 2030; large secondary PM

reductions from significantly lower NOX

and SOX emissions will add to the

overall positive impact on airborne

particles. These reductions will be very

cost-effective compared to other

measures to reduce PM pollution.

Because direct PM emissions from

gasoline vehicles are related the

presence of sulfur in gasoline, no new

emission control devices, beyond what

manufacturers are expected to install to

meet the NOX and NMOG standards,

will be necessary to provide the

reductions expected for these pollutants

under the program. The standards will

provide valuable insurance against

increases in PM emissions from LDVs,

LDTs, and MDPVs.

Finally, the Tier 2/Gasoline Sulfur

program will significantly reduce CO

emissions from LDVs, LDTs, and

MDPVs. (See Chapter III of the RIA for

an analysis of these reductions.) The

technical changes needed to meet the

NMOG standards will also result in CO

reductions sufficient to meet the CO

standards. Thus, these CO reductions

will be very cost-effective since they

will not require any new emission

control devices beyond what

manufacturers are expected to install to

meet the NOX and NMOG standards.

We conclude, then, that today’s final

rule is a major source of ozone

precursor, PM, and CO emission

reductions when compared to other

available options. The discussions of

cost and cost effectiveness later in this

preamble and in the RIA explain the

derivation of cost effectiveness

estimates and compares them to the cost

effectiveness of other alternatives. That

discussion indicates that this program

will have a cost effectiveness

comparable to both the Tier 1 and NLEV

standards and will also be cost effective

when compared to non-mobile source

programs.

III. Air Quality Need For and Impact Of

Today’s Action

In the absence of significant new

controls on emission, tens of millions of

Americans would continue to be

exposed to unhealthy levels of air

pollution. Emissions from passenger

cars and light trucks are a significant

contributor to a number of air pollution

problems. Today’s action will

significantly reduce emissions from cars

and light trucks and hence will

significantly reduce the health risks

posed by air pollution. This section

summarizes the results of the analyses

we performed to arrive at our

determination that continuing air

quality problems are likely to exist, that

these air quality problems would be in

part due to emissions from cars and

light trucks, and that the new standards

promulgated by today’s final rule will

improve air quality and mitigate other

environmental problems.

A. Americans Face Serious Air Quality

Problems That Require Further Emission

Reductions

Air quality in the United States

continues to improve. Nationally, the

1997 air quality levels were the best on

record for all six criteria pollutants. 10 In

fact, the 1990s have shown a steady

trend of improvement, due to reductions

in emissions from most sources of air

pollution, from factories to motor

vehicles. Despite great progress in air

quality improvement, in 1997 there

were still approximately 107 million

people nationwide who lived in

counties with monitored air quality

levels above the primary national air

quality standards. 11 There are also

people living in counties outside of the

air monitoring network where violations

of the NAAQS could have also occurred

during the year. Moreover, unless there

are reductions in overall emissions

beyond those that are scheduled to be

achieved by already committed controls,

many of these Americans will continue

to be exposed to unhealthy air.

Ambient ozone is formed in the lower

atmosphere through a complex

interaction of VOC and NOX emissions.

Cars and light trucks emit a substantial

fraction of these emissions. Ambient PM

is emitted directly from cars and light

trucks; it also forms in the atmosphere

from NOX, sulfur oxides (SOX), and

VOC, all of which are emitted by motor

vehicles. When ozone exceeds the air

quality standards, otherwise healthy

people often have reduced lung function

and chest pain, and hospital admissions

for people with respiratory ailments like

asthma increase; for longer exposures,

permanent lung damage can occur.

Similarly, fine particles can penetrate

deep into the lungs. Results of studies

suggest a likely causal role of ambient

PM in contributing to reported effects,

such as: premature mortality, increased

hospital admissions, increased

respiratory symptoms, and changes in

lung tissue. When either ozone or PM

air quality problems are present, those

hardest hit tend to be children, the

elderly, and people who already have

health problems.

The health effects of high ozone and

PM levels are not the only reason for

concern about continuing air pollution.

Ozone and PM also harm plants and

damage materials. PM reduces visibility

and contributes to significant visibility

impairment in our national parks and

monuments and in many urban areas. In

addition, air pollution from motor

vehicles contributes to cancer and other

health risks, acidification of lakes and

streams, eutrophication of coastal and

inland waters, and elevated drinking

water nitrate levels. These problems

impose a substantial burden on public

health, our economy, and our

ecosystems.

In recognition of this burden,

Congress has passed and subsequently

amended the Clean Air Act. The Clean

Air Act requires each state to have an

approved State Implementation Plan

(SIP) that shows how an area plans to

meet its air quality obligations,

including achieving and then

maintaining attainment of all of the

National Ambient Air Quality Standards

(NAAQS), such as those for ozone and

PM. The Clean Air Act also requires

EPA to periodically re-evaluate the

NAAQS in light of new scientific

information. Our most recent reevaluation of the ozone and PM NAAQS

led us to revise both standards (62 FR

38856, July 18, 1997 and 62 FR 38652,

July 18, 1997). These revised standards

reflected additional information that

had become available since the previous

revision of the ozone and PM standards,

respectively.

On May 14, 1999, a panel of the

United States Court of Appeals for the

District of Columbia Circuit reviewed

EPA’s revisions to the ozone and PM

NAAQS and found, by a 2–1 vote, that

sections 108 and 109 of the Clean Air

Act, as interpreted by EPA, represent

unconstitutional delegations of

Congressional power. American

Trucking Ass’n., Inc. et al., v.

Environmental Protection Agency, 175

F.3d 1027 (D.C. Cir. 1999). Among other

things the Court remanded the record

6706 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

for the 8-hour ozone NAAQS and the

PM2.5 NAAQS to EPA. On October 29,

1999, EPA’s petition for rehearing by the

three judge panel was denied, with the

exception that the panel modified its

prior ruling regarding EPA’s authority to

implement a revised ozone NAAQS

under Part D subpart 2 of Title I. EPA’s

petition for rehearing en banc by the full

Circuit was also denied, although five of

the nine judges considering the petition

agreed to rehear the case.

As a result of the Court’s decision,

requirements on the States to implement

the new 8-hour ozone standard have

been suspended although the standard

itself is still in force and the science

behind it has generally not been

contradicted. The court also did not

question EPA’s findings regarding the

health effects of PM10 and PM2.5.

However, due to the uncertainty

regarding the status of the new NAAQS,

we will rely on the preexisting NAAQS

in determining air quality need under

section 202(i) of the Act.

Carbon monoxide (CO) can cause

serious health effects for those who

suffer from cardiovascular disease, such

as angina pectoris. There has been

considerable progress in attaining the

longstanding NAAQS for carbon

monoxide, largely through more

stringent standards for CO from motor

vehicles. This progress has been made

despite large increases in travel by

vehicle. In 1997, there were about 9

million people living in three counties

with CO concentrations above the level

of the CO NAAQS. In the recent past,

this figure has fluctuated up and down.

At the present time there are 15 counties

classified as serious CO nonattainment

areas, all with a recent history of

NAAQS violations. At this time,

prospects for these areas attaining by the

serious CO area attainment deadline of

December 31, 2000 are uncertain. While

violations of the NAAQS have not

occurred recently in most of the other

33 counties still classified as

nonattainment, even these must

demonstrate that they will remain safely

below the NAAQS for ten years despite

expected growth in vehicle travel and

other sources of CO emissions before

they can be reclassified to attainment.

Because of the large role of motor

vehicles in causing high ambient CO

concentrations, where there is reason to

be concerned about CO attainment and

maintenance, local areas look to

national emission standards for most of

the solution.

As discussed below, EPA has also

finalized regulations that regions and

states implement plans for protecting

and improving visibility in the 156

mandatory Federal Class I areas as

defined in Section 162(a) of the Clean

Air Act. These areas are primarily

national parks and wilderness areas.

To accomplish the goal of full

attainment in all areas according to the

schedules for the various NAAQS, and

to achieve the goals of the visibility

program, the federal government must

assist the states by reducing emissions

from sources that are not as practical to

control at the state level as at the federal

level. Vehicles and fuels move freely

among the states, and they are produced

by national or global scale industries.

Most individual states are not in a

position to regulate these industries

effectively and efficiently. The Clean

Air Act therefore gives EPA primary

authority to regulate emissions from the

various types of highway vehicles and

their fuels. Our actions to reduce

emissions from these and other national

sources are a crucial and essential

complement to actions by states to

reduce emissions from more localized

sources.

If we were not to adopt new standards

to reduce emissions from cars and light

trucks, emissions from these vehicles

would remain a large portion of the

emissions burden that causes elevated

ozone and continued nonattainment

with the ozone NAAQS, which in turn

would affect tens of millions of

Americans. Because the contribution of

cars and light trucks to both local

emissions and transported pollution

would be so great, and the expected

emission reduction shortfall in many

areas is so large, further reductions from

cars and light trucks will be an

important element of many attainment

strategies, especially for ozone in the

2007 to 2010 time frame. The

contribution of these vehicles to PM

exposure and PM nonattainment would

also remain significant, and would

increase considerably if diesel engines

are used in more cars or light trucks.

Furthermore, without new standards,

steady annual increases in fleet size and

miles of travel would outstrip the

benefits of current emission controls,

and would cause ozone-forming

emissions from cars and trucks to grow

each year starting about 2013.

The standards being promulgated by

today’s actions will reduce emissions of

ozone precursors and PM precursors

from cars and light trucks greatly.

However, even with this decrease, many

areas will likely still find it necessary to

obtain additional reductions from other

sources in order to fully attain the ozone

and PM NAAQS. Their task will be

easier and the economic impact on their

industries and citizens will be lighter as

a result of the standards promulgated by

today’s actions. Following

implementation of the Regional Ozone

Transport Rule, states will have already

adopted emission reduction

requirements for nearly all large sources

of VOC and NOX for which costeffective control technologies are

known. Those that remain in

nonattainment therefore will have to

consider their remaining alternatives.

Many of the state and local programs

states may consider as alternatives are

very costly, and the emissions impact

from each additional emissions source

subjected to new emissions controls

would be considerably smaller than the

emissions impact of the standards being

promulgated today. Therefore, the

emission reductions from these

standards for gasoline, cars, and light

trucks will ease the need for states to

find first-time reductions from the

mostly smaller sources that have not yet

been controlled, including area sources

that are closely connected with

individual and small business activities.

The emission reductions from the

standards being promulgated today will

also reduce the need for states to seek

even deeper reductions from large and

small sources already subject to

emission controls.

We project that today’s actions will

also have important benefits for carbon

monoxide, regional visibility, acid rain,

and coastal water quality.

For these and other reasons discussed

in this document, we have determined

that significant emission reductions will

still be needed by the middle of the next

decade and beyond to achieve and

maintain further improvements in air

quality in many, geographically

dispersed areas. We also believe that a

significant portion of these emission

reductions will be obtained by reducing

emissions from cars and light trucks as

a result of today’s actions. We believe

that such reductions are necessary

(since cars and light trucks are such

large contributors to current and

projected ozone problems) and

reasonable (since these reductions can

be achieved at a reasonable cost

compared to other alternative

reductions).

The remainder of this section

describes the health and environmental

problems that today’s actions will help

mitigate and the expected health and

environmental benefits of these actions.

Ozone is discussed first, followed by

PM, other criteria pollutants, visibility,

air toxics, and other environmental

impacts. The emission inventories and

air quality analyses are explained more

fully in the Regulatory Impact Analysis

for today’s actions.

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6707

12Total column ozone, a large percentage of

which occurs in the stratosphere and a smaller

percentage of which occurs in the troposphere,

helps to provide a protective layer against

ultraviolet radiation.

B. Ozone

1. Background on Ozone Air Quality

Ground-level ozone is the main

harmful ingredient in smog.12 Ozone is

produced by complex chemical

reactions when its precursors, VOC and

NOX, react in the presence of sunlight.

Short-term (1–3 hours) and prolonged

(6–8 hours) exposures to ambient ozone

at levels common in many cities have

been linked to a number of health

effects of concerns. For example,

increased hospital admissions and

emergency room visits for respiratory

causes have been associated with

ambient ozone exposures at such levels.

Repeated exposures to ozone can make

people more susceptible to respiratory

infection, result in lung inflammation,

and aggravate pre-existing respiratory

diseases such as asthma. Other health

effects attributed to ozone exposures

include significant decreases in lung

function and increased respiratory

symptoms such as chest pain and

cough. These effects generally occur

while individuals are engaged in

moderate or heavy exertion.

Children active outdoors during the

summer when ozone levels are at their

highest are most at risk of experiencing

such effects. Other at-risk groups

include adults who are active outdoors

(e.g., outdoor workers), and individuals

with pre-existing respiratory disease

such as asthma and chronic obstructive

lung disease. In addition, longer-term

exposures to moderate levels of ozone

present the possibility of irreversible

changes in the lungs which could lead

to premature aging of the lungs and/or

chronic respiratory illnesses.

Ozone also affects vegetation and

ecosystems, leading to reductions in

agricultural and commercial forest

yields, reduced growth and survivability

of tree seedlings, and increased plant

susceptibility to disease, pests, and

other environmental stresses (e.g., harsh

weather). In long-lived species, these

effects may become evident only after

several years or even decades, thus

having the potential for long-term

effects on forest ecosystems. Groundlevel ozone damage to the foliage of

trees and other plants also can decrease

the aesthetic value of ornamental

species as well as the natural beauty of

our national parks and recreation areas.

Many areas which were classified as

nonattainment when classifications

were made under the 1990 Clean Air

Act Amendments have not experienced

violations more recently. However, 50

metropolitan areas had ozone design

values above the NAAQS in either or

both of the 1995–1997 and the 1996–

1998 monitoring periods. In many urban

areas, the downward trend in ozone that

prevailed earlier has become less strong

or stopped in the last few years, even

when adjustments are made for

meteorological conditions. We believe

that one factor that has worked against

ozone improvement in the last few years

has been the growing use of light trucks

with higher emissions than the cars

used formerly. The predictions of future

ozone concentrations used in

developing today’s action take account

of this growing use of light trucks.

2. Additional Emission Reductions Are

Needed To Attain and Maintain the

Ozone NAAQS

a. Summary

We have determined that additional

emission reductions are needed to attain

and maintain the 1-hour ozone NAAQS.

This overall conclusion is based on our

prediction that 26 metropolitan areas

are each certain or highly likely to need

additional reductions, and that an

additional 12 areas each have a

moderate to significant probability of

needing them.

To determine whether additional

reductions are needed in order to attain

and maintain the ozone NAAQS, we

used ozone modeling to predict what

areas would not attain the NAAQS in

the future. We accounted for the

emission reductions that have already

been achieved, those that will be

achieved in the future by actions

already underway, and increases in

emissions expected from increased use

of sources of pollution.

In our May 13, 1999 proposal, we

presented information from

photochemical modeling we performed

to predict what areas would meet the

ozone NAAQS in 2007. The year 2007

falls after the expected date of most

emission reductions which states are

required to achieve or have otherwise

committed to achieve, and near the

attainment deadline for many ozone

nonattainment areas. We presented

additional information from the same

photochemical modeling work in two

supplemental notices, on June 30, 1999

(to better explain the basis for our

proposal in light of the Court’s ruling on

the 8-hour ozone NAAQS), and October

25, 1999 (to explain the implications for

our Tier 2/Gasoline Sulfur proposal

from our more recent proposal, which

we expect to make final shortly, to reinstate the 1-hour ozone NAAQS in

many areas). In Response to Comments

on these Federal Register notices, we

made revisions to our own ozone

modeling. We also obtained ozone

modeling results from a number of state

air planning agencies and from members

of the automobile manufacturing

industry. We have considered all of this

information as part of our determination

that the regulations promulgated in this

rule are needed and appropriate.

Based on the available ozone

modeling and other information, we

project that there are 26 metropolitan

areas which will be unable to attain and

maintain the NAAQS, in the absence of

additional reductions. These areas had a

combined population of over 86 million

in 1996, and are distributed across most

regions of the U.S. We have concluded

that each is certain or very likely to

require additional reductions to attain

the NAAQS. Taken together and

considering their number, size, and

geographic distribution, these areas

establish the case that additional

reductions are needed in order to attain

and maintain the 1-hour standard.

In addition, our analysis suggests

there will be other areas that will have

problems attaining and maintaining

compliance with the one-hour ozone

standard in the future. There are 12

additional metropolitan areas with a

total 1996 population of over 25 million

people in this category. EPA’s ozone

modeling for 2007 predicts exceedances

for each of these areas. However, for six

of them local recent monitoring

information is not indicating

nonattainment. Given how close to

nonattainment these areas are, EPA

believes it is likely that at least a

significant subset of this group of areas

will face compliance problems by 2007

or beyond if additional actions to lower

air emissions are not taken. This belief

is based on historical experience with

areas that will undergo economic and

population growth over time and that

are in larger regions that are also

experiencing growth. The other six areas

in this group are nonattainment now,

and local modeling shows them

reaching attainment by 2005 or 2007.

Modeling uncertainties and growth

beyond the attainment date make it

likely that at least some of these areas

will also face compliance problems if

additional actions to lower air emissions

are not taken. This situation further

supports our determination that

additional reductions in mobile source

emissions are needed for attainment and

maintenance.

We would like to emphasize that the

advantages of the Tier 2/Gasoline Sulfur

program will be enjoyed by the whole

country. There are important advantages

for approximately 30 more metropolitan

6708 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

13As measured by ozone design value.

14While the use of these emissions estimates was

new to our baseline ozone modeling in the latest

ozone modeling, they were not new to this

rulemaking, having already been used in

calculations of cost-effectiveness in the draft RIA.

We therefore were able to consider public

comments on these estimates prior to using them

in the latest ozone modeling

areas, with close to 30 million people

residing in them, whose ozone levels are

now within 10 percent of violating the

1-hour NAAQS.13 Most of these areas

have been in nonattainment in the past.

We believe the emission reductions

from the Tier 2/Gasoline Sulfur program

are an important component of an

overall EPA-state approach to enable

these areas to continue to maintain

clean air given expected growth. EPA

believes that the long term ability of the

states to continue to meet the NAAQS

is extremely important. In the future,

EPA will be considering additional

approaches for assisting in maintenance

of the NAAQS. Also, we believe that the

Tier 2/Gasoline Sulfur program has

important benefits for other

nonattainment areas which our

modeling and local modeling show to be

on a path to come into attainment in the

next eight years. For these areas, the

extra emission reductions from the

program will take some of the

uncertainty out of their plan to attain

the standard and give them a head start

on developing their plan to stay in

attainment.

In every area of the country, the new

standards will give transportation

planning bodies and industrial

development leaders more options

within the area’s overall emissions

constraints. This will allow local and

state officials to better accommodate

local needs and growth opportunities.

With these new standards for vehicles

and gasoline, unusually adverse weather

or strong local economic growth will be

less likely to cause ozone levels high

enough to trigger the planning

requirements of the Clean Air Act. In

addition, by reducing emissions and

ozone levels across the nation as a

whole, there will be less transport of

ozone between areas, reducing the

amount of ozone entering downwind

areas. This will give the downwind

areas a better opportunity to maintain

and attain the NAAQS through local

efforts.

All of our determinations presented

here about the need for the Tier 2/

Gasoline Sulfur program take into

account the prior NOX reductions we

expect from the Regional Ozone

Transport Rule. This rule is now in

litigation. If the outcome of that

litigation reduces the NOX reductions

that will be achieved, the need for the

Tier 2/Gasoline Sulfur program will be

even greater.

b. Ozone Modeling Presented in Our

Proposal and Supplemental Notices

The ozone modeling we presented in

our proposal and the two supplemental

notices was originally conducted as part

of our development of the Regional

Ozone Transport Rule. The ‘‘revised

budget’’ emission control scenario we

modeled for the Regional Ozone

Transport Rule contained the right set of

existing and committed emission

controls for it to serve as the starting

point for making our determination on

the need for additional emission

reductions. We added a new ‘‘control

case’’ to represent the effects of our

proposed vehicle and gasoline

standards.

This ozone modeling provided

predictions of ozone concentrations in

2007 across the eastern U.S., under

certain meteorological conditions.

Predictions of attainment or

nonattainment are based on these

predicted ozone concentrations. Two

approaches to making attainment

predictions have been used or

advocated in the past: a rollback

approach and an exceedance approach.

In the NPRM of May 13, 1999, we

presented predictions of attainment and

nonattainment using a rollback

approach. For the 1-hour standard, we

reported that 8 metropolitan areas and

two rural counties were predicted to be

in nonattainment in 2007 under the

rollback method. In the first

supplemental notice of June 30, 1999 we

presented a prediction that 17 areas

would be nonattainment based on the

exceedance method, and invited

comment on all aspects of the modeling

and its interpretation. Our second and

last notice on October 27, 1999,

presented predictions of violations

using the exceedance method for

additional areas which we had

previously excluded because the 1-hour

standard did not apply to them. This

was in anticipation of the reinstatement

of the 1-hour standard to these areas,

which we proposed on October 25, 1999

and expect to complete very soon. 64 FR

57524. We also announced that we were

conducting another round of modeling,

described below. See the Response to

Comments document for more

discussion of the rollback and

exceedance approaches.

c. Updated and Additional Ozone

Modeling

We have updated and expanded our

ozone modeling. We updated the ozone

modeling so that it is now based on

estimates of vehicle emissions that

reflect the most recent data and our best

understanding of several aspects of

emissions estimation.14 We also

changed most of the episodes for which

we modeled ozone concentrations, with

all of our final episode days coming

from a single calendar year. By selecting

days from within a single year, we

responded to a comment that the

original episode periods might together

contain an atypically high number of

days favorable to ozone formation for

some parts of the country. The new

episodes are also better at representing

conditions that lead to high ozone in

areas along the Gulf Coast, whose

ozone-forming conditions were not well

represented in the episodes used for the

original modeling.

While we considered these

improvements necessary and

appropriate in light of comments and

other information available to us, the

actual results of the two rounds of

modeling with regard to the need for

additional reductions have turned out to

be similar. The latest round of modeling

provided us ozone predictions for 2007

and 2030 in the eastern U.S., and for

2030 in the western U.S. There are some

differences in specific results, where

and when the two models can be

directly compared. However, the same

conclusion would be reached from

either, namely that there is a broad set

of areas with predicted ozone

concentrations in 2007 above 0.124

ppm, in the baseline scenario without

additional emission reductions.

We have compared and supplemented

our own ozone modeling with other

modeling studies, either submitted to us

as comments to this rulemaking, as state

implementation plan (SIP) revisions, or

brought to our attention through our

consultations with states on SIP

revisions that are in development. The

ozone modeling in the SIP revisions has

the advantage of using emission

inventories that are more specific to the

area being modeled, and of using

meteorological conditions selected

specifically for each area. Also, the SIP

revisions included other evidence and

analysis, such as analysis of air quality

and emissions trends, observation based

models that make use of data on

concentrations of ozone precursors,

alternative rollback analyses, and

information on the responsiveness of

the air quality model. For some areas,

we decided that the predictions of

attainment or nonattainment from our

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6709

15EPA’s modeling presumed that cars and light

trucks will continue to meet the emission levels of

the National Low Emissions Vehicle (NLEV)

program after model year 2003, even though the

program will end in model year 2003 or shortly

thereafter. Had our modeling not included such

levels in its inventory assumptions, trends for

ozone concentrations would have shown earlier

increases in ozone concentrations.

16The date of the predicted violation was 2007

for most areas, 2010 in the case of Los Angeles, CA,

and 2030 in the case of Portland-Salem, OR.

17With regard to eventual final action on the 1-

hour attainment demonstration for Washington, DC,

the issue of the continuation of the NLEV standards

is mooted by the promulgation of the Tier 2/

Gasoline Sulfur program. A portion of the emission

reductions from this program will replace the post2003 model year NLEV reductions assumed in the

SIP.

modeling were less reliable than

conclusions that could be drawn from

this additional evidence and analysis.

For example, in some areas our episodes

did not capture the meteorological

conditions that have caused high ozone,

while local modeling did so.

d. Results and Conclusions

As discussed in detail below, it is

clear that the NOX and VOC reductions

to be achieved through the Tier 2/

Gasoline Sulfur program are needed to

attain and maintain compliance with

the 1 hour ozone NAAQS. Although the

general pattern observed in our

modeling indicates improvements in the

near term, growth in overall emissions

will lead to worsening of air quality

over the long term.

Based on our ozone modeling, we

have analyzed ozone predictions for 52

metropolitan areas for 1996, 2007, and

2030. In addition, we reviewed ozone

attainment modeling and other evidence

covering 15 of these areas, from SIP

submittals or from modeling underway

to support SIP revisions. This local

modeling addressed only the current or

requested attainment date in each area.

We then made attainment and

nonattainment predictions from this

information.

The general pattern we observed with

the baseline scenario, i.e., without new

emission reductions, is a broad

reduction between 1996 and 2007 in the

geographic extent of ozone

concentrations above the NAAQS, and

in the frequency and severity of

exceedances. This is consistent with the

national emissions inventory trend

between these two years. At the same

time, we also found that peak ozone

concentrations and the frequency of

exceedances in 2030 were generally

somewhat higher than in 2007 for most

areas analyzed. This too is consistent

with our analysis of emission inventory

trends, which shows that the total NOX

inventory from all sources will decline

from 2007 to about 2015 and then begin

to increase due to growth in the activity

of emission sources. In 2030, our

analysis predicts that NOX emissions

from all sources will be about one

percent higher than in 2007. While we

did not model ozone concentrations for

years between 2007 and 2030, we expect

that they would track the national

emissions trend by showing a period of

improvement after 2007 and then

deterioration, although individual areas

will vary due to local source mix and

growth rates.15

Within this general pattern of ozone

attainment changes between 1996 and

2030, we have determined that 26

metropolitan areas are certain or highly

likely to need additional reductions to

attain and maintain the 1-hour ozone

NAAQS. These 26 areas are those that

have current violations of the 1-hour

ozone NAAQS and are predicted by the

best ozone modeling we have available

to still be in violation without a new

federal vehicle program in 2007.16

Based on the general trends described

above, without further emissions

reductions many of these areas may also

have violations continuously

throughout the period from 2007 to

2030, while others may briefly attain

and then return to nonattainment on or

before 2030. These 26 metropolitan

areas are listed in Table III.B–1, along

with their 1996 population which totals

over 86 million. The sizes of these areas

and their geographical distribution

strongly support an overall need for

additional reductions in order to attain

and maintain under section 202(i).

Because ozone concentration patterns

causing violations of the 1-hour NAAQS

are well established to endanger public

health or welfare, this determination

also supports our actions today under

the general authority of sections

202(a)(1), 202(a)(3), and 202(b).

As indicated above, in reaching this

conclusion about these 26 areas, we

examined local ozone modeling in SIP

submittals. These local analyses are

considered to be more extensive than

our own modeling for estimating

whether there would be NAAQS

nonattainment without further emission

reductions, when interpreted by a

weight of evidence method which meets

our guidance for such modeling. One of

the areas which submitted a SIP

revision was a special case. We have

recently proposed to approve the 1-hour

ozone attainment demonstration for the

nonattainment area of Washington, D.C.

(but not Baltimore). We have

nevertheless included this area on the

list of 26 that are certain or highly likely

to require further reductions to attain

and maintain, because its SIP

attainment demonstration assumed

emission reductions from vehicles

meeting the National Low Emissions

Vehicle (NLEV) standards.

However, by its own terms, the NLEV

standards would not extend beyond the

2003 model year if we did not

promulgate Tier 2 vehicle standards at

least as stringent as the NLEV standards.

See 40 CFR 86.1701–99(c). Thus, the

emission reductions relied upon from

2004 and later model year NLEV

vehicles are themselves ‘‘further

reductions’’ for the purposes of CAA

section 202(i).17 The local modeling

indicating attainment with these

reductions is therefore strong evidence

that further reductions are needed past

2003, beyond those provided by the Tier

1 program. Based on this, and on the

fact that our own ozone modeling

showed the Washington, DC area to

violate the NAAQS in 2007 even with

full NLEV emission reductions, we have

concluded that it should be included

with areas that do require further

reductions to attain and maintain the 1-

hour ozone NAAQS.

The 1-hour ozone NAAQS presently

does not apply in 12 of the 26 areas

listed in Table III.B–1, but we have

proposed to re-instate it and expect to

complete that action shortly. These

areas are indicated in the table. Our

decision to include these areas on this

list is based on the contingency that we

will re-instate the 1-hour standard in

these areas. However, even if we

considered only the 14 areas where the

1-hour standard applies as of the

signature date of this notice, we have

concluded that our determination

would be the same.

TABLE III.B–1.—TWENTY-SIX METROPOLITAN AREAS WHICH ARE CERTAIN OR HIGHLY LIKELY TO REQUIRE

ADDITIONAL EMISSION REDUCTIONS

IN ORDER TO ATTAIN AND MAINTAIN

THE 1-HOUR OZONE NAAQS

Metropolitan area

1996

Population

(millions)

Atlanta, GA MSA ...................... 3.5

Barnstable-Yarmouth, MA

MSAa .................................... 0.2

Baton Rouge, LA MSA ............. 0.6

Beaumont-Port Arthur, TX MSA 0.4

Birmingham, AL MSA ............... 0.9

Boston-Worcester-Lawrence,

MA–NH–ME–CT CMSAa ...... 5.6

Charlotte-Gastonia-Rock Hill,

NC–SC MSAa ....................... 1.3

6710 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

18The SIP revisions for Chicago and Milwaukee

demonstrated that these two areas as well as Benton

Harbor and Grand Rapids areas in Michigan (which

are maintenance areas but have experienced ozone

NAAQS violations recently) would not experience

NAAQS violations in 2007, with a strategy that

relied only on Tier 1 vehicle emission standards.

We have also recently proposed to approve the 1-

hour attainment demonstration for Greater

Connecticut, covering the Hartford and New

London areas, which assumed full NLEV emission

reductions. However, Connecticut is committed in

its SIP to adopt California vehicle standards if

NLEV does end with the 2003 model year if a more

stringent federal program is not promulgated. The

California standards are more stringent than NLEV.

The case of one additional area whose attainment

demonstration we recently proposed to approve,

Western Massachusetts (Springfield), should be

explained here to avoid possible confusion. Our

own ozone modeling predicted that Springfield

would attain the NAAQS in 2007. Massachusetts

has adopted the California vehicle emission

standards, so there is no issue of the continuation

of the NLEV standards.

TABLE III.B–1.—TWENTY-SIX METROPOLITAN AREAS WHICH ARE CERTAIN OR HIGHLY LIKELY TO REQUIRE

ADDITIONAL EMISSION REDUCTIONS

IN ORDER TO ATTAIN AND MAINTAIN

THE 1-HOUR OZONE NAAQS—Continued

Metropolitan area

1996

Population

(millions)

Cincinnati-Hamilton, OH–KY–IN

CMSA .................................... 1.9

Dallas-Fort Worth, TX CMSA ... 4.6

Houma, LA MSAa .................... 0.2

Houston-Galveston-Brazoria,

TX CMSA .............................. 4.3

Huntington-Ashland, WV–KY–

OH MSAa .............................. 0.3

Indianapolis, IN MSAa .............. 1.5

Los Angeles-Riverside-San

Bernardino CA CMSA ........... 15.5

Louisville, KY–IN MSA ............. 1.0

Macon, GA MSAa .................... 0.3

Memphis, TN–AR–MS MSAa ... 1.1

Nashville, TN MSAa ................. 1.1

New York-Northern New Jersey-Long Island, NY–NJ–

CT–PA CMSA ....................... 19.9

Philadelphia-Wilmington-Atlantic City, PA–NJ–DE–MD

CMSA .................................... 6.0

Pittsburgh, PA MSA .................. 2.4

Portland-Salem, OR–WA

CMSAa .................................. 2.1

Providence-Fall River-Warwick,

RI–MA MSAa ........................ 1.1

Richmond-Petersburg, VA

MSAa .................................... 0.9

St. Louis, MO–IL MSA .............. 2.5

Washington-Baltimore, DC–

MD–VA–WV CMSA .............. 7.2

Total Population ............. 86.3

Notes:

aThe 1-hour ozone NAAQS does not currently apply, but we have proposed and expect to re-instate it shortly.

There are 12 additional metropolitan

areas, with another 25.3 million people

in 1996, for which the available ozone

modeling suggests significant risk of

failing to attain and maintain the 1-hour

ozone NAAQS without additional

emission reductions. Table III.B–2 lists

the areas we put in this second category.

Our own ozone modeling predicted

these 12 areas to need further reductions

to avoid violations in 2007. For six of

these areas, recent air quality

monitoring data indicate violation, but

we have reviewed local ozone modeling

and other evidence indicating

attainment in 2007.18 Based on this

evidence, we have kept these areas

separate from the previous set of 26

areas which we consider certain or

highly likely to need additional

reductions. However, we still consider

there to be a significant risk of failure to

attain and maintain in these six areas

because this local modeling has

inherent uncertainties, as all ozone

modeling does. Moreover, the local

modeling did not examine the period

after initial attainment.

For the other six of the 12 areas, the

air quality monitoring data shows

current attainment but with less than a

10 percent margin below the NAAQS.

This suggests these areas may remain

without violations for some time, but we

believe there is still a moderate risk of

future violation of the NAAQS because

meteorological conditions may be more

severe in the future.

It is highly likely that at least some of

these 12 areas will violate the NAAQS

without additional reductions, and it is

a distinct possibility that many of them

will do so. We consider the situation in

these areas to support our determination

that, overall, additional reductions are

needed for attainment and maintenance.

However, we reiterate that our

predictions for the 26 areas listed in

Table III.B–1, and even our predictions

for only the 14 of those 26 for which the

1-hour standard now applies, are a

sufficient basis for our determination of

an overall need for additional

reductions and for our actions today.

TABLE III.B–2.—TWELVE METROPOLITAN AREAS WITH MODERATE TO

SIGNIFICANT RISK OF FAILING TO

ATTAIN AND MAINTAIN THE 1-HOUR

OZONE NAAQS WITHOUT ADDITIONAL EMISSION REDUCTIONS

Metropolitan area

1996

Population

(millions)

Benton Harbor, MI MSAa ......... 0.2

Biloxi-Gulfport-Pascagoula, MS

MSAa .................................... 0.3

TABLE III.B–2.—TWELVE METROPOLITAN AREAS WITH MODERATE TO

SIGNIFICANT RISK OF FAILING TO

ATTAIN AND MAINTAIN THE 1-HOUR

OZONE NAAQS WITHOUT ADDITIONAL EMISSION REDUCTIONS—

Continued

Metropolitan area

1996

Population

(millions)

Chicago-Gary-Kenosha, IL–IN–

WI CMSA .............................. 8.6

Cleveland-Akron, OH CMSAa .. 2.9

Detroit-Ann Arbor-Flint, MI

CMSAa .................................. 5.3

Grand Rapids-Muskegon-Holland, MI MSAa ...................... 1.0

Hartford, CT MSA ..................... 1.1

Milwaukee-Racine, WI CMSA .. 1.6

New London-Norwich, CT–RI

MSAa .................................... 1.3

New Orleans, LA MSAa ........... 0.3

Pensacola, FL MSAa ............... 0.4

Tampa, FL MSAa ..................... 2.2

Total Population ............. 25.3

Notes:

aThe 1-hour ozone NAAQS does not currently apply, but we have proposed and expect to re-instate it shortly.

e. Issues and Comments Addressed

We received detailed comments from

the automobile industry related to ozone

modeling and the need for additional

emission reductions in order to attain

and maintain. These were of three types.

Accuracy of modeling ozone

concentrations.—The automobile

industry commenters pointed out that in

the modeling presented with our

proposal, the ozone model and

exceedance predicted violations of the

NAAQS in 1995 in areas where

monitoring data indicated no violations.

They cited these cases as examples of

model inaccuracy. We have made

improvements to our emissions

estimates, our episodes, and other

aspects of the modeling system. These

changes have improved the accuracy of

the predicted ozone concentrations.

Also, as stated above, our list of 26 areas

that support our finding that additional

reductions are needed does not include

any areas where recent monitoring data

shows no violations. The final RIA

addresses issues of model accuracy in

more depth.

As explained in the final RIA, our

very latest estimates of car and light

truck emissions without the benefits of

our new standards are actually

somewhat higher than the estimates

used in the final round of ozone

modeling, because the most recent data

indicate even more serious adverse

emissions effects from sulfur in

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6711

19We did not include the Los Angeles-RiversideSan Bernardino area in this analysis, since it was

not covered by our 2007 modeling, but we do

believe it is rightly part of the basis for a

determination on the need for additional

reductions.

20As explained in the final RIA, our very lastest

estimates of car and light truck emissions without

the benefits of our new standards are actually

somewhat higher than the estimates used in the

final round of ozone modeling, because more recent

data indicate even more serious adverse emissions

effects from sulfur in gasoline. Thus, we think our

predictions of ozone nonattainment may be

conservative.

gasoline. Thus, we think our predictions

of ozone nonattainment using emission

estimates prepared before this most

recent data on sulfur was considered,

may be conservative. This topic is

discussed in more detail in section

III.B.3.

Prediction of attainment/

nonattainment.—For most areas, we

predicted 2007 or 2030 attainment or

nonattainment based on the exceedance

method. The exceedance method

predicts an area to be in attainment only

if there are no predicted exceedances of

the NAAQS during any episode day.

However, for the areas for which we

have received 1-hour attainment

demonstrations in SIP revisions, our

predictions were based on a larger and

more robust set of data. When a state’s

modeling shows an exceedance that

would otherwise indicate

nonattainment, we allow the state to

submit a variety of other evidence and

analysis, such as locality specific

meteorological conditions, analysis of

air quality and emissions trends,

observational based models that make

use of data on concentrations of ozone

precursors, a rollback analysis, and

information on the responsiveness of

the air quality model. We then make a

weight-of-evidence determination of

attainment or nonattainment based on

consideration of all this local evidence.

We did this in forming the set of 26

areas we consider certain or highly

likely to need additional reductions to

attain or maintain, in some cases

concluding that attainment was

demonstrated and in others that it was

not.

The auto industry commenters

recommended the use of rollback as the

single method for making attainment

and nonattainment predictions from

predicted ozone concentrations. They

stated that the rollback method would

be more consistent than the exceedance

method with the NAAQS’s allowance of

three exceedances in a three year

period. They also believed that the

rollback method would compensate for

what they considered to be model over

predictions of ozone concentrations. We

believe that the rollback method is not

appropriate for use as the sole, or even

a primary, test of 1-hour ozone

attainment or nonattainment. A rollback

analysis may overlook violations that

occur away from ozone monitors, and it

may inappropriately project the effect of

a recent period of favorable weather into

the prediction of future attainment. In

determining the attainment and

maintenance prospects of numerous

areas, as here, it is not possible to

assemble and consider the full set of

local evidence that should accompany

any consideration of a rollback analysis.

In such a situation, we believe that the

exceedance method is the appropriate

choice. A fuller explanation of our

reasons for considering the exceedance

method more appropriate than rollback

is given in our Response to Comments

document.

We have not completely excluded the

rollback approach from the

determinations in this rulemaking. We

have considered it for those areas for

which we had enough information to

allow us to consider it in its proper

context, i.e., for those areas covered by

recent 1-hour SIP submissions. Of these

areas, we concluded that some will not

attain without additional reductions and

some will.

While we disagree with the use of the

rollback method, we have conducted a

hypothetical analysis of 2007 attainment

in all areas based only on our own

ozone modeling, applying the rollback

method recommended by the

commenters. We calculated in this

analysis that 15 metropolitan areas and

three other counties with nearly 56

million in population in 1996 would

violate the NAAQS in 2007. Moreover,

these 15 metro areas are geographically

spread out 19. We believe that this result

using the rollback method does not fully

capture the likely nonattainment that

would exist in 2007 in the absence of

additional emission reductions.

However, even if we were to consider

the use of rollback valid, we consider

this set of areas to also be an adequate

basis for making the same

determinations we have made based on

the more appropriate exceedance-based

analysis. The details of our hypothetical

analysis using the rollback method are

given in the final RIA and the technical

support document for our ozone

modeling analyses.

Ozone modeling and predictions.—

Members of the automobile

manufacturing industry submitted two

modeling studies: (1) a repetition of our

first round of modeling of the 37-state

eastern U.S. domain but with their

recommendations regarding estimates of

motor vehicle emissions in 2007 and

with the rollback method used to

predict 2007 nonattainment, and (2)

finer grid modeling for three smaller

domains, also with their recommended

estimates of emissions and with

nonattainment predicted using a

rollback method. Both modeling efforts

showed less widespread nonattainment

than we have determined and described

here. Taken together, these studies

predicted 2007 violations by the

rollback method in or downwind of

New York City, Chicago, Milwaukee,

western Michigan, Baton-Rouge, and

Houston.

The main difference between the

automobile industry’s ozone modeling

and ours is in the emission estimates.

We have reviewed the emissions

estimates used in the industry studies.

We concluded that the industry’s

emissions estimates employ

inappropriate analytical steps in the

calculation. Among the problems are

that the adjustments for the benefits of

inspection and maintenance programs

were not consistent with the base

estimate of in-use emissions, and the

sales trend towards light trucks and

SUVs was not properly captured. Also,

as stated, we disagree with the use of

the rollback approach as the sole test of

attainment. As a consequence, we

conclude that the industry’s ozone

modeling is not an appropriate basis for

making predictions of future attainment

or nonattainment. The final RIA

explains in detail how we have

addressed these and other emissions

modeling issues in a manner which is

more technically consistent and

correct,20 and how we have considered

the results from rollback analyses but

only as part of broad weight-of-evidence

determinations for areas for which this

was possible at this time. Our point-bypoint review is given in our Response to

Comments document.

The material on ozone modeling

submitted by the commenters, having

been prepared by the rollback method,

was difficult to re-interpret according to

our preferred exceedance method.

However, it appears that if this

modeling were interpreted by the

exceedance method, it would indicate

2007 nonattainment in Baltimore and

Washington, D.C. in addition to New

York City, Chicago, Milwaukee, western

Michigan, Baton-Rouge, and Houston.

Overall, we conclude that the material

submitted by the automobile industry

does not contradict the facts we have

used to make our determinations or the

actions we are taking today.

f. 8-Hour Ozone

The predictions of ozone

concentrations from the ozone modeling

6712 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

21Emission Trend Report, 1997.

22The auto manufacturer and northeastern state

commitments to the NLEV program are scheduled

to end in 2004 without further EPA action on Tier

2 standards, although continued voluntary

compliance by automobile manufacturers and the

affected states is a possibility. Our analysis of

emission trends and the emission benefits expected

from today’s action assumes for the base scenario

a continuation of the NLEV program past 2004. If

the NLEV program does not continue beyond 2004,

the reductions resulting from Tier 2 would be larger

than what is shown here. It also includes all other

control measures assumed to be implemented in

local areas, such as reformulated gasoline in all

required and opt-in areas and enhanced I/M where

required.

23Also, if the NLEV program ends in model year

2004 or shortly thereafter, as scheduled, this trend

would reverse more quickly in all areas.

can be used to make predictions of

attainment or nonattainment with the 8-

hour ozone NAAQS. In our draft RIA,

we estimated that 28 metropolitan areas

and 4 rural counties with a combined

population of 80 million people would

violate the 8-hour ozone NAAQS in

2007 without additional emission

reductions. Commenters noted

differences between exact rollback

procedure we had used in this

projection and the steps specified in

recent draft guidance we have issued on

8-hour ozone modeling. We agree with

the commenters that the steps specified

in our guidance are the correct ones to

use. However, since we are not basing

our promulgation of the Tier 2/Gasoline

Sulfur Program on the 8-hour ozone

NAAQS, we have not made any new

predictions of 8-hour ozone

nonattainment areas in 2007. Based on

our findings in previous analyses of this

sort, however, we believe that in the

absence of the Tier 2/Gasoline Sulfur

program there would be 8-hour

nonattainment areas that are not also

areas which we have concluded are

certain or highly likely to violate the 1-

hour NAAQS. If we considered it

appropriate to proceed with

implementation of the 8-hour standard,

these areas would support our

determination on the need for emission

reductions, and the appropriateness and

necessity of the vehicle and gasoline

standards we are establishing.

3. Cars and Light-duty Trucks Are a Big

Part of the NOX and VOC Emissions,

and Today’s Action Will Reduce This

Contribution Substantially

Emissions of VOCs and NOX come

from a variety of sources, both natural

and man-made. Natural sources,

including emissions that have been

traced to vegetation, account for a

substantial portion of total VOC

emissions in rural areas. The remainder

of this section focuses on the

contribution of motor vehicles to

emissions from human sources. Manmade VOCs are released as byproducts

of incomplete combustion as well as

evaporation of solvents and fuels. For

gasoline-fueled cars and light trucks,

approximately half of the VOC

emissions come from the vehicle

exhaust and half come from the

evaporation of gasoline from the fuel

system. NOX emissions are dominated

by man-made sources, most notably

high-temperature combustion processes

such as those occurring in automobiles

and power plants. Emissions from cars

and light trucks are currently, and will

remain, a major part of nationwide VOC

and NOX emissions. In 1996, cars and

light trucks comprised 25 percent of the

VOC emissions and 21 percent of the

NOX emissions from human sources in

the U.S.21 The contribution in

metropolitan areas was generally larger.

We have made significant

improvements in the analysis used to

estimate the emission inventory impacts

of this action, including improving the

emission factor modeling, using more

detailed local modeling input, and using

a more conservative (lower) estimate of

VMT growth. These changes are

detailed in the Regulatory Impact

Analysis for this rule. The following

discussion is based on this improved

analysis.

In addition to the improvements

which are incorporated in this analysis,

we also made further improvements in

the emission factor modeling after

analyzing comments which we did not

have time to incorporate into the

detailed inventory analysis described

here. The most notable change is related

to data which indicates that NOX and

NMOG emissions are even more

sensitive to gasoline sulfur than

previously thought. This change and

others are described in detail in the

Response to Comments. Our early

analysis of these changes indicates that

incorporating them into this analysis

would provide further support for this

action because these changes result in

both increases in the baseline emissions

without Tier 2 and in the reductions

that would result from Tier 2. For

example, in the detailed inventory

analysis we report below, we project

nationwide Tier 2/Gasoline Sulfur

control NOX reductions from cars and

light trucks of 856,471 tons per year in

2007. Using the version of the emission

factor model that incorporates these

additional changes increases the

estimated Tier 2 reductions to

approximately 1.0 million tons per year

in 2007 (estimated baseline emissions

without Tier 2 increase from 3.1 million

tons per year in 2007 to approximately

3.7 million tons per year using the

version of the emission factor model

that incorporates these additional

changes). Therefore, the estimates of the

inventory reductions given here (and

used as the basis for the ozone air

quality analysis) are clearly

conservative.

Motor vehicle emission controls have

led to significant improvements in

emissions released to the air (the

‘‘emission inventory’’) and will

continue to do so in the near term 22. In

the current analysis, we continue to find

that total emissions from the car and

light truck fleet would continue to

decline for a period, even if we were not

establishing the Tier 2/Gasoline Sulfur

program. This decline would result from

the introduction of cleaner reformulated

gasoline in 2000, the introduction of

National Low Emission Vehicles

(NLEVs) and vehicles complying with

the Enhanced Evaporative Test

Procedure and Supplemental Federal

Test Procedures, and the continuing

removal of older, higher-emitting

vehicles from the in-use vehicle fleet.

On a per mile basis, VOC and NOX

emissions from cars and light trucks

combined would have continued to

decline well beyond 2015, reflecting the

continuing effect of fleet turnover under

existing emission control programs.

However, projected increases in vehicle

miles traveled (VMT) will cause total

emissions from these vehicles to

increase. With this increase in travel

and without additional controls, we

project that combined NOX and VOC

emissions for cars and light trucks

without the Tier 2/Gasoline Sulfur

program would increase starting in 2013

and 2016, respectively, so that by 2030

they would return to levels above or

nearly the same as they will be in 2000.

In cities experiencing rapid growth,

such as Charlotte, North Carolina, the

near-term trend towards lower

emissions tends to reverse sooner.23

With additional improvements in the

modeling done in Response to

Comments, we now estimate that

without the Tier 2/Gasoline Sulfur

program, there will be a constant

increase in these emission over time.

Figure III–1 illustrates this expected

trend in car and light truck NOX

emissions in the absence of today’s

action. The figure also allows the

contribution of cars to be distinguished

from that of light trucks. The figure

clearly shows the impact of steady

growth in light truck sales and travel on

overall light-duty NOX emissions; the

decrease in overall light-duty emission

levels is due solely to reductions in LDV

emissions. In 2000, we project that

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6713

24Today’s action for both vehicles and fuels will

apply in 49 states and the U.S. territories, excluding

only California. There will also be emissions

reductions in California from vehicles that relocate

or visit from other states. However, much of the

emissions inventory analysis for this action was

made for a 47-state region which excludes

California, Alasks, and Hawaii. The latter two states

were not included in the scope of ozone, PM and

economic benefits modeling.

trucks will produce about 50 percent of

combined car and light truck NOX

emissions. We project that truck

emissions would actually increase after

2000, and over the next 30 years, trucks

would grow to dominate light-duty NOX

emissions. By 2010, we project trucks

would make up two-thirds of light-duty

NOX emissions; by 2020, nearly threequarters of all light-duty NOX emissions

would be produced by trucks.

BILLING CODE 6560–50–P

BILLING CODE 6560–50–C

Today’s action will significantly decrease NOX and VOC emissions from cars and light trucks, and will delay the

date by which NOX and VOC emissions will begin to increase due to continued VMT growth. With Tier 2/Gasoline

Sulfur control, light-duty vehicle NOX and VOC emissions are projected to continue their downward trend past 2020.

Table III.B–3 shows the annual tons of NOX that we project will be reduced by today’s action.24 These projections

include the benefits of low sulfur fuel and the introduction of Tier 2 car and light truck standards.

TABLE III.B–3.—NOX EMISSIONS FROM CARS AND LIGHT TRUCKS AS PERCENT OF TOTAL EMISSIONS, AND REDUCTIONS

DUE TO TIER 2/GASOLINE SULFUR CONTROL (TONS PER YEAR) a

Year

Light-duty

tons— without

tier 2

Light-duty percent of total

without tier 2

Light-duty tons

reduced by tier

2 c, c

2007 ............................................................................................................................................. 3,095,698 16 856,471

2010 ............................................................................................................................................. 2,962,093 16 1,235,882

2015 ............................................................................................................................................. 2,968,707 17 1,816,767

2020 ............................................................................................................................................. 3,160,155 17 2,220,210

6714 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

25California Air Resources Board, Executive

Order G–99–037, May 20, 1999, Attachment A, 6–

7, 10. These NOX reductions represent a small fraction of the emission reductions needed in the

South Coast to attain the NAAQS.

TABLE III.B–3.—NOX EMISSIONS FROM CARS AND LIGHT TRUCKS AS PERCENT OF TOTAL EMISSIONS, AND REDUCTIONS

DUE TO TIER 2/GASOLINE SULFUR CONTROL (TONS PER YEAR) a—Continued

Year

Light-duty

tons— without

tier 2

Light-duty percent of total

without tier 2

Light-duty tons

reduced by tier

2 b, c

2030 ............................................................................................................................................. 3,704,747 19 2,795,551

Notes:

aEstimates exclude California, Alaska, and Hawaii, although reductions will occur in all three.

b Does not include emission reductions from heavy-duty gasoline vehicles.

cThese numbers represent a conservative estimate of the benefits of the Tier 2/Sulfur program. Based on the updated emission factor model

developed in response to comments, the program will result in significantly larger benefits. For example, our new model projects NOX reductions

of 1,100,000 tons in 2007.

The lower sulfur levels in today’s

action will produce large emission

reductions on pre-Tier 2 vehicles as

soon as low-sulfur gasoline is

introduced, in addition to enabling Tier

2 vehicles to achieve lower emission

levels. Among the pre-Tier 2 vehicles,

the largest per vehicle emission

reductions from lower sulfur in gasoline

will be achieved from vehicles which

automobile manufacturers will have

sold under the voluntary National Low

Emission Vehicle program. These

vehicles are capable of substantially

lower emissions when operated on low

sulfur fuel. Older technology vehicles

experience a smaller but significant

effect.

In 2007, when all gasoline will meet

the new sulfur limit and when large

numbers of 2004 and newer vehicles

meeting these standards will be in use,

the combined NOX emission reduction

from vehicles and fuels will be over

850,000 tons per year. After 2007,

emissions will be reduced further as the

fleet turns over to Tier 2 vehicles

operating on low sulfur fuel. By 2020,

NOX emissions will be reduced by 70%

from the levels that would occur

without today’s action. This reduction

equals the NOX emissions from over 164

million pre-Tier 2 cars and light trucks.

This reduction represents a 12 percent

reduction in NOX emissions from all

manmade sources.

VOC emissions will also be reduced

by today’s action, with reductions

increasing as the fleet turns over. We

estimate that the reductions as a percent

of emissions from cars and light trucks

will be 7 percent in 2007 and grow to

17 percent in 2020.

As discussed earlier, in California,

smaller but still substantial reductions

in both NOX and VOC will be achieved

because vehicles visiting and relocating

to California will be designed to meet

these standards. Also, vehicles from

California visiting other states will not

be exposed to high sulfur fuel.

California Air Resources Board staff

have estimated that Tier 2/Sulfur will

reduce NOX emissions in the South

Coast Air Quality Management District

by approximately 4 tons per day in

2007.25 CARB staff plan to incorporate

these reductions in their revised

attainment plan for this district, which

includes most of the Los Angeles-Long

Beach region.

These estimates of emission

reductions reflect a mixture of urban,

suburban, and rural areas. However,

cars and light trucks generally make up

a larger fraction of the emission

inventory for urban and suburban areas,

where human population and personal

vehicle travel is more concentrated than

emissions from other sources such as

heavy-duty highway vehicles, power

plants, and industrial boilers. We have

estimated emission inventories for three

cities using the same methods as were

used to project the nationwide

inventories, and we present the results

for 2007 below in Table III.B–4.

These results confirm that light-duty

vehicles make up a greater share of the

NOX emission inventories in urban

areas than they do in the nationwide

inventory. While these vehicles’ share of

national NOX emissions in 2007 is about

16 percent, it is estimated to be about

34 percent in the Atlanta area. There is

also a range in VOC contributions, with

Atlanta again being the area with the

largest car and light truck contribution

at 17 percent. In metropolitan areas with

high car and light truck contributions,

today’s action will represent a larger

step towards attainment since it will

have a larger effect on total emissions.

TABLE III.B–4—Proportion of the Total Urban Area NOX and VOC Inventory in 2007 Attributable to Light-Duty

Vehiclesa

Region NOX

(percent)

VOC

(percent)

Nationwide ....................................................................................................................................................................... 16 13

New York urban area ...................................................................................................................................................... 18 6

Atlanta urban area ........................................................................................................................................................... 34 17

Charlotte urban area ........................................................................................................................................................ 24 15

Notes:

a The estimates reflect continuation of NLEV beyond 2004.

Another useful perspective from

which to view the magnitude of the

emission reductions from today’s

proposal is in terms of the additional

emission reductions from all human

sources that areas will need to attain the

1-hour ozone standard. For this

analysis, we reviewed our proposals for

action on the 1-hour attainment

demonstrations submitted by the states.

With these proposals, EPA identified

estimates of additional emission

reductions (measures in addition to

those submitted by the state in their

plans) necessary for attainment for some

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6715

26EPA assessment of air quality changes for 2007

and 2030 focused on 37 states in the East because

these states cover most of the areas with 1-hour

nonattainment problems.

of the areas. These estimates of

additional emission reductions are

documented in the individual Federal

Register Notices. Using these estimates

and the estimates of Tier 2 reductions

developed for today’s action, we have

determined what portion of these

additional emission reductions would

be accounted for by today’s action.

These estimates are reported in Table

III.B–5, which shows the contribution of

Tier 2/Sulfur NOX reductions to the

additional emission reduction necessary

for attainment for three metropolitan

areas. For example, for the New York

nonattainment area, 89% of the

additional NOX emission reductions

needed for attainment are provided for

with today’s action. This leaves 11% of

the additional NOX emission reductions

to be addressed by the State through

other local sources.

EPA and the States already have

significant efforts underway to lower

ozone precursor emissions through

national regulations and State

Implementation Plans. Table III.B–5

shows the contribution of Tier 2 to the

substantial State-led efforts to provide

attainment with the ozone NAAQS.

Since the Tier 2 program has evolved in

the past year after much of the States’

efforts were completed, many of the

States were unable to estimate the

benefits of Tier 2 in their areas. EPA’s

proposal actions on these SIPs for the

ozone NAAQS addresses the need for

Tier 2 in many areas. More specifically,

Tier 2 is being used to help States

identify additional measures, in

addition to those in their plans,

necessary for attainment.

These estimates are subject to change

as the states review and comment on

our proposed action on the SIPs. These

figures show that today’s proposal

would make a very substantial

contribution to these cities’ attainment

programs, but that there will still be a

need for additional reductions from

other sources. The emission reductions

from today’s proposal would clearly not

exceed the reductions needed from an

air quality perspective for these areas.

TABLE III.B–5.—CONTRIBUTION OF TIER 2/SULFUR NOX REDUCTIONS TO OZONE ATTAINMENT EFFORTS OF SELECTED

NONATTAINMENT AREAS

Nonattainment area (attainment date)

Percent of additional NOX

reductions necessary for

attainment

From tier 2 Needed

after tier 2

Baltimore (2005) .............................................................................................................................................................. 100 0

New York (2007) .............................................................................................................................................................. 89 11

Philadelphia (2005) .......................................................................................................................................................... 87 13

4. Ozone Reductions Expected From

This Rule

The large reductions in emissions of

ozone precursors from today’s standards

will be very beneficial to federal and

state efforts to lower ozone levels and

bring about attainment with the current

one-hour ozone standard. The air

quality modeling for the final rule

shows that improvements in ozone

levels are expected to occur throughout

the country because of the Tier 2/

Gasoline Sulfur program.26 EPA found

that the program significantly lowers

model-predicted exceedances of the

ozone standard. In 2007 the number of

exceedances in CMSA/MSAs is

forecasted to decline by nearly onetenth and in 2030, when full turnover of

the vehicle fleet has occurred, the

program lowers such exceedances by

almost one-third. In these same areas,

the total amount of ozone above the

NAAQS is forecasted to decline by

about 15 percent in 2007 and by more

than one-third in 2030. In the vast

majority of areas, the air quality

modeling predicts that the program will

lower peak summer ozone

concentrations for both 2007 and 2030.

The reduction in daily maximum ozone

is nearly 2 ppb on average in 2007 and

over 5 ppb on average in 2030. These

reductions contribute to EPA’s

assessment that the program will

provide the large set of public health

and environmental benefits summarized

in Section IV.D of the Preamble. The

forecasted impacts of the program on

ozone in 2007 and 2030 are further

described in the Tier 2 Air Quality

Modeling Technical Support Document.

During the public comment period on

the proposed rule, EPA received several

comments that expressed concern about

potential increases in ozone that might

occur as a result of this rule. As

indicated above, the air quality

modeling results indicate an overall

reduction in ozone levels in 2007 and

2030 during the various episodes

modeled. In addition to ozone

reductions, a few areas had predicted

ozone increases in portions of the area

during parts of the episodes modeled. In

most of these cases, we observed a net

reduction in ozone levels in these areas

due to the program. In the very small

number of exceptions to this, the

Agency did find benefit from reduction

of peak ozone levels. Based upon a

careful examination of this issue,

including EPA’s modeling results as

well as consideration of the modeling

and analyses submitted by commenters,

it is clear that the significant ozone

reductions from this rule outweigh the

limited ozone increases that may occur.

Additional details on this issue are

provided in the Response to Comments

document and in the Tier 2 Air Quality

Modeling Technical Support Document.

Taken together, EPA believes these

results indicate that it will be much

easier for States to develop State

Implementation Plans which will attain

and maintain compliance with the onehour ozone standard. EPA will work

with States conducting more detailed

local modeling of their specific ozone

situation, to ensure that their SIPs will

provide attainment. Notably, there are

also other upcoming federal measures to

lower ozone precursors that will aid

these efforts. If the State modeling of

local programs shows a need, the

Agency will work with states to plan

further actions to produce attainment

with the NAAQS in order to protect the

public’s health and the environment.

Further details on EPA’s modeling

results can be found in the Agency’s

Response to Comments and technical

support documents.

C. Particulate Matter

The need to control the contribution

of cars and light trucks to ambient

concentrations of particulate matter

(PM) is the basis for our adoption of the

new PM emission standards for

vehicles. PM is also a supplemental

consideration in our promulgation of

6716 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

27U.S. EPA (1998) National Air Pollutant

Emission Trends Update, 1970–1997. EPA–454/E–

98–007. There is evidence from ambient studies

that emissions of these materials may be

overestimated and/or that once emitted they have

less of an influence on monitored PM

concentrations (of both PM10 and PM2.5) than this

inventory share would suggest.

the vehicle emission standards for NOX

and VOC, and for the limits on sulfur in

gasoline, because SOx, NOX, and VOC

are PM precursors.

For cars and for light trucks under

3750 pounds loaded vehicle weight, we

are establishing new emission standards

under the provisions of CAA section

202(i), which ties our action to the need

for additional emission reductions in

order to attain and maintain the

NAAQS. The NAAQS relevant to the

PM emission standards is the PM10

NAAQS. The PM10 NAAQS also

provides additional but not essential

support to our promulgation of the NOX

and VOC standards, since these

standards are fully supportable on the

basis of the 1-hour ozone NAAQS.

For the vehicles not subject to CAA

202(i), and for the gasoline sulfur limits,

our actions are tied to determinations

regarding public health and welfare

risks more broadly, under CAA sections

202(a), 202(b), and 211(c). The role of

NOX, VOC, and PM emissions in

contributing to atmospheric

concentrations of PM10 is an important

element of the risk that these emissions

pose to public health and welfare.

PM also poses risks to public health

not fully reflected in the PM10 NAAQS.

Though EPA has not relied on the

adverse health impacts of fine PM to

promulgate this rule, it is well

established that such impacts exist. A

summary of these effects is given in the

next section. In addition, based on the

available science, EPA’s Office of

Research and Development has recently

submitted to a committee of our Science

Advisory Board a draft assessment

document which contains a proposed

conclusion that diesel exhaust is a likely

human cancer hazard and is a potential

cause of other nonmalignant respiratory

effects. The scientific advisory

committee has met to discuss this

document, and we are awaiting written

review comments from the committee.

We expect to submit a further revision

of the document to the advisory

committee before we make the

document final.

1. Background on PM

Particulate matter (PM) represents a

broad class of chemically and physically

diverse substances that exist as discrete

particles (liquid droplets or solids) over

a wide range of sizes. The NAAQS that

regulates PM addresses only PM with a

diameter less than or equal to 10

microns, or PM10. The coarse fraction of

PM10 consists of those particles which

have a diameter in the range between

2.5 and 10 microns, and the fine fraction

consists of those particles which have a

diameter less than or equal to 2.5

microns, or PM2.5. These particles and

droplets are produced as a direct result

of human activity and natural processes,

and they are also formed as secondary

particles from the atmospheric

transformation of emissions of SOX,

NOX, ammonia, and VOCs.

Natural sources of particles in the

coarse fraction of PM10 include

windblown dust, salt from dried sea

spray, fires, biogenic emanation (e.g.,

pollen from plants, fungal spores), and

volcanoes. Fugitive dust and crustal

material (geogenic materials) comprise

approximately 80% of the coarse

fraction of the PM10 inventory as

estimated by methods in use today.27

Manmade sources of these coarser

particles arise predominantly from

combustion of fossil fuel by large and

small industrial sources (including

power generating plants, manufacturing

plants, quarries, and kilns), wind

erosion from crop land, roads, and

construction, dust from industrial and

agricultural grinding and handling

operations, metals processing, and

burning of firewood and solid waste.

Coarse-fraction PM10 remains

suspended in the atmosphere a

relatively short period of time.

Most of the emission sources listed for

coarse particles also have a substantial

fine particle fraction. Their share of the

PM2.5 inventory is somewhat smaller,

however, because of the role of other

sources that give rise primarily to PM2.5.

The other sources of PM2.5 include

carbon-based particles emitted directly

from gasoline and diesel internal

combustion engines, sulfate-based

particles formed from SOX and

ammonia, nitrate-based particles formed

from NOX and ammonia, and

carbonaceous particles formed through

transformation of VOC emissions. PM2.5

particles from fugitive dust and crustal

sources comprise substantially less than

their share of coarse PM emissions,

approximately one-half of the directly

emitted PM2.5 inventory as estimated by

methods in use today. The presence and

magnitude of crustal PM2.5 in the

ambient air is much lower even than

suggested by this smaller inventory

share, due to the additional presence of

secondary PM from non-crustal sources

and the removal of a large portion of

crustal emissions close to their source.

This near-source removal results from

crustal PM’s lack of inherent thermal

buoyancy, low release height, and

interaction with surrounding vegetation

(which acts to filter out some of these

particles).

Secondary PM is dominated by sulfate

particles in the eastern U.S. and parts of

the western U.S., with nitrate particles

and carbonaceous particles dominant in

some western areas. Mobile sources can

reasonably be estimated to contribute to

ambient secondary nitrate and sulfate

PM in proportion to their contribution

to total NOX and SOX emissions.

The sources, ambient concentration,

and chemical and physical properties of

PM10 vary greatly with time, region,

meteorology, and source category. A

first step in developing a plan to attain

the PM10 NAAQS is to disaggregate

ambient PM10 into the basic categories

of sulfate, nitrate, carbonaceous, and

crustal PM, and then determine the

major contributors to each category

based on knowledge of local and

upwind emission sources. Following

this approach, SIP strategies to reduce

ambient PM concentrations have

generally focused on controlling fugitive

dust from natural soil and soil disturbed

by human activity, paving dirt roads

and controlling soil on paved roads,

reducing emissions from residential

wood combustion, and controlling

major stationary sources of PM10 where

applicable. The control programs to

reduce stationary, area, and mobile

source emissions of sulfur dioxide,

oxides of nitrogen, and volatile organic

compounds in order to achieve

attainment with the sulfur dioxide and

ozone NAAQS also have contributed to

reductions in the fine fraction of PM10

concentrations. In addition, the EPA

standards for PM emissions from

highway and nonroad engines are

contributing to reducing PM10

concentrations. As a result of all these

efforts, in the last ten years, there has

been a downward trend in PM10

concentrations, with a leveling off in the

later years.

Particulate matter, like ozone, has

been linked to a range of serious

respiratory health problems. Scientific

studies suggest a likely causal role of

ambient particulate matter in

contributing to a series of health effects.

The key health effects categories

associated with particulate matter

include premature mortality,

aggravation of respiratory and

cardiovascular disease (as indicated by

increased hospital admissions and

emergency room visits, school absences,

work loss days, and restricted activity

days), changes in lung function and

increased respiratory symptoms,

changes to lung tissues and structure,

and altered respiratory defense

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6717

28U.S. EPA, 1996, Air Quality Criteria for

Particulate Matter, EPA/600/P–95/001aF. Review of

the National Ambient Air Quality Standards for

Particulate Matter: Policy Assessment of Scientific

and Technical Information, OAQPS Staff Paper,

EPA–452 R–96–013, July 1996.

29The annual average PM10 NAAQS is based on

a three-year average, and the 24-hour NAAQS is

based on expected exceedances over a three-year

period.

30Health Assessment Document for Diesel

Emissions, SAB Review Draft EPA/600/8–90/057D.

November 1999. The document is available

electronically at http://www.epa.gov/ncea/

diesel.htm.

mechanisms. PM also causes damage to

materials and soiling. It is a major cause

of substantial visibility impairment in

many parts of the U.S.

Motor vehicle particle emissions and

the particles formed by the

transformation of motor vehicle gaseous

emissions tend to be in the fine particle

range. Fine particles are a special health

concern because they easily reach the

deepest recesses of the lungs. Scientific

studies have linked fine particles (alone

or in combination with other air

pollutants), with a series of significant

health problems, including premature

death; respiratory related hospital

admissions and emergency room visits;

aggravated asthma; acute respiratory

symptoms, including aggravated

coughing and difficult or painful

breathing; chronic bronchitis; and

decreased lung function that can be

experienced as shortness of breath.

These effects are discussed further in

EPA’s ‘‘Staff Paper’’ and ‘‘Air Quality

Criteria Document’’ for particulate

matter.28

EPA first established primary (healthbased) and secondary (welfare-based)

National Ambient Air Quality Standards

for PM10 in 1987. The annual and 24-

hour primary PM10 standards were set at

50 μg/m33, and 150 μg/m3,

respectively.29 In July 1997, the primary

standards were revised to add two new

PM2.5 standards. At the same time, we

changed the statistical form of the

primary PM10 standard and set all the

secondary standards to be the same as

the primary.

On May 14, 1999, a panel of the U.S.

Court of Appeals for the District of

Columbia Circuit reviewed EPA’s

revisions to the ozone and PM NAAQS

and found, by a 2–1 vote, that sections

108 and 109 of the Clean Air Act, as

interpreted by EPA, represent

unconstitutional delegations of

Congressional power. American

Trucking Ass’ns, Inc., et al., v.

Environmental Protection Agency, 175

F.3d 1027 (D.C. Cir. 1999). Among other

things the Court remanded the record

for the 8-hour ozone NAAQS and the

PM2.5 NAAQS to EPA. On October 29,

1999, EPA’s petition for rehearing by the

three judge panel was denied, with an

exception regarding the revised ozone

NAAQS. EPA’s petition for rehearing en

banc by the full Circuit was also denied,

although five of the nine judges

considering the petition agreed to rehear

the case.

The pre-existing PM10 NAAQS

remains in effect (except for one area—

Boise, ID—where prior to the court’s

decision we had determined it no longer

to apply). We believe that given the

uncertain status of the new PM2.5

NAAQS, it is most appropriate to rely

primarily on the pre-existing PM10

NAAQS in establishing the Tier 2/

Gasoline Sulfur program’s vehicle

emission standards and limits on sulfur

in gasoline. However, because we

believe, and the Court did not dispute,

that there are very substantial public

health risks from PM2.5 and substantial

health and economic benefits from

reducing PM2.5 concentrations, we have

conducted analyses of the PM2.5 changes

likely to occur from the Tier 2/Gasoline

Sulfur program. These analyses are

summarized in the section of this

preamble dealing with the economic

benefits of the new standards, section

IV.D.5, and corresponding sections of

the final RIA.

There is additional concern regarding

the health effects of PM from diesel

vehicles, apart from the health effects

which were considered in setting the

NAAQS for PM10 and PM2.5. Diesel PM

contains small quantities of chemical

species that are known carcinogens, and

diesel PM as a whole has been

implicated in occupational

epidemiology studies. EPA’s Office of

Research and Development has

considered these studies, and has

recently submitted to a committee of our

Science Advisory Board a draft

conclusion that diesel exhaust is a

‘‘highly likely’’ human cancer hazard.30

Because we are awaiting a formal

response from our advisory committee

before revising and finalizing our

assessment document, we are not

relying on the conclusions in this

document as formal support for our

action today. More information about

this aspect of PM air quality is given in

section III.F of this preamble.

2. Need for Additional Reductions to

Attain and Maintain the PM10 NAAQS

The most recent PM10 monitoring data

indicates that 15 designated PM10

nonattainment counties, with a

population of almost 9 million in 1996,

violated the PM10 NAAQS in the period

1996–1998. The areas that are violating

do so because of exceedances of the 24-

hour PM10 NAAQS. No areas had

monitored violations of the annual

standard in this period. Table III.C–1

lists the 15 counties. The table also

indicates the classification for each area

and the status of our review of the State

Implementation Plan.

TABLE III.C–1.—FIFTEEN PM10 NONATTAINMENT AREAS VIOLATING THE PM10 NAAQS IN 1996–1998 a

Area Classification SIP approved?

1996

Population

(millions)

Clark Co., NV ................................................................................................................. Serious .................... No ..................... 0.93

El Paso, TX .................................................................................................................... Moderate ................. Yes ................... 0.67

Gila, AZ ........................................................................................................................... Moderate ................. No ..................... 0.05

Imperial Co., CA ............................................................................................................. Moderate ................. No ..................... 0.14

Inyo Co., CA ................................................................................................................... Moderate ................. No ..................... 0.02

Kern Co., CA .................................................................................................................. Serious .................... No ..................... 0.62

Mono Co., CA ................................................................................................................. Moderate ................. No ..................... 0.01

Kings Co., CA ................................................................................................................. Serious .................... No ..................... 0.11

Maricopa Co., AZ ........................................................................................................... Serious .................... No ..................... 2.61

Power Co., ID ................................................................................................................. Moderate ................. No ..................... 0.01

Riverside Co., CA ........................................................................................................... Serious .................... No ..................... 1.41

San Bernardino Co., CA ................................................................................................. Serious .................... No ..................... 1.59

Santa Cruz Co., AZ ........................................................................................................ Moderate ................. No ..................... 0.04

Tulare Co., CA ................................................................................................................ Serious .................... No ..................... 0.35

6718 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

31Regulatory Impact Analyses for the Particulate

Matter and Ozone National Ambient Air Quality

Standards and Proposed Regional Haze Rule,

Innovative Strategies and Economics Group, Office

of Air Quality Planning and Standards, U.S.

Environmental Protection Agency, Research

Triangle Park, N.C., July 16, 1997.

32We used the more recent modeling for 2030

rather than the earlier modeling for 2010, because

the modeling the 2030 incorporates more recent

estimates of emissions inventories. Our emission

estimates in our final RIA indicate that PM10

emissions under the basline scenario increase

steadily between 1996 and 2030, for 47 states

combined and for four specific cities, suggesting

that areas in nonattainment in both 1996–1998 and

2030 will be in nonatainment in the intermediate

years as well assuming no further emission

reductions. A factor tending to make Table III.C–2

shorter is that we have not relied on the sourcereceptor matrix model’s prediction of 24-hour

nonattainment, as those predictions on an

individual areas basis are less reliable than the

predictions of annual average nonattainment.

TABLE III.C–1.—FIFTEEN PM10 NONATTAINMENT AREAS VIOLATING THE PM10 NAAQS IN 1996–1998 a—Continued

Area Classification SIP approved?

1996

Population

(millions)

Walla Walla Co., WA ...................................................................................................... Moderate ................. Yes ................... 0.05

Total Population ................................................................................................... ............................. ...................... 8.61

aAlthough we do not believe that we are limited to considering only designated nonattainment areas in implementing CAA section 202(i), we

have focused on the designated areas in the case of PM10. An official designation of PM10 nonattainment indicates the existence of a confirmed

PM10 problem that is more than a result of a one-time monitoring upset or a results of PM10 exceedances attributable to natural events. In addition to these designated nonattainment areas, there are 15 unclassified counties in 12 geographically spread out states, with a 1996 population

of over 4 million, for which the state has reported PM10 monitoring data for this period indicating a PM10 NAAQS violation. We have not yet excluded the possibility that a one-time monitoring upset or a natural event(s) is responsible for the monitored violations in 1996–1998 in the 15 unclassified counties. We adopted a policy in 1996 that allows areas whose PM10 exceedances are attributable to natural events to remain unclassified if the state is taking all reasonable measures to safeguard public health regardless of the source of PM10 emissions. Areas that remain unclassified areas are not required to submit attainment plans, but we work with each of these areas to understand the nature of the PM10 problem

and to determine what best can be done to reduce it. The Tier 2/Gasoline Sulfur program will reduce PM10 concentrations in these 15 unclassified counties, because all have car and light truck travel that contributes to PM10 and precursor emissions loadings. This reduction will assist

these areas in reducing their PM10 nonattainment problem, if a problem is confirmed upon closer examination of each local situation. Boise, ID,

had also been classified as a PM10 nonattainment area at one time and was monitored to have a PM10 NAAQS violation in 1996–1998. However, the pre-existing PM10 NAAQS does not presently apply in Boise, ID, because in the period between our revision of the old PM10 NAAQS

and the Court’s decision to vacate the revised PM10 NAAQS, we determined that Boise was in attainment with the old PM10 NAAQS and that it

therefore no longer applied in that area.

Because the types and sources of PM10

are complex and vary from area to area,

the best projections of future PM10

concentrations are the local emission

inventory and air quality modeling

analyses that states have developed or

are still in the process of developing for

their PM10 attainment plans. We do

employ a modeling approach, known as

the source-receptor matrix approach, for

relating emission reductions to PM10

reductions on a national scale. This

approach is one of our established air

quality models for purposes of

quantifying the health and welfare

related economic benefits of PM

reductions from major regulatory

actions. One application of this

modeling approach was for the

Regulatory Impact Analysis for the

establishment of the new PM NAAQS 31.

This model is also the basis for the

estimates of PM10 (and PM2.5)

concentrations reductions we have used

to estimate the economic benefits of the

Tier 2/Gasoline Sulfur program in 2030.

Its use for this purpose is described in

the final RIA. In both applications, we

modeled an emissions scenario

corresponding to controls currently in

place or committed to by states. As

such, this scenario is an appropriate

baseline for determining if further

reductions in emissions are needed in

order to attain and maintain the PM10

NAAQS.

In the RIA for the establishment of the

PM NAAQS, we projected that in 2010

there will be 45 counties not in

attainment with the original PM10

NAAQS . We cited these modeling

results in our proposal for the Tier 2/

Gasoline Sulfur program and in our first

supplemental notice. After reviewing

public comments on our presentation of

these modeling results, we have

concluded that while the sourcereceptor matrix approach is a suitable

model for estimating PM concentration

reductions for economic benefits

estimation, it is not a tool we can use

with high confidence for predicting that

individual areas that are now in

attainment will become nonattainment

in the future. However, we believe the

source-receptor matrix approach is

appropriate for, and is a suitable tool

for, determining that a current

designated nonattainment area has a

high risk of remaining in PM10

nonattainment at a future date.

Therefore, we have cross-matched the

results for 2030 from our final RIA for

Tier 2 and the list of current PM10

nonattainment areas with monitored

violations in 1996 to 1998 shown in

Table III.C–1.32 Based on this, we

conclude that the 8 areas shown in

Table III.C–2 have a high risk of failing

to attain and maintain without further

emission reductions. These areas have a

population of nearly 8 million. Included

in the group are the counties that are

part of the Los Angeles, Phoenix, and

Las Vegas metropolitan areas, where

traffic from cars and light trucks is

substantial. California areas will benefit

from the Tier 2/Gasoline Sulfur program

because of travel within California by

vehicles originally sold outside the

state, and by reduced poisoning of

catalysts from fuel purchased outside of

California.

TABLE III.C–2.—EIGHT AREAS WITH A

HIGH RISK OF FAILING TO ATTAIN

AND MAINTAIN THE PM10 NAAQS

WITHOUT FURTHER REDUCTIONS IN

EMISSIONS

Area

1996

population

(millions)

Clark Co., NV ........................... 0.93

Imperial Co., CA ....................... 0.14

Kern Co., CA ............................ 0.62

Kings Co., CA ........................... 0.11

Maricopa Co., AZ ..................... 2.61

Riverside Co., CA ..................... 1.41

San Bernardino Co., CA ........... 1.59

Tulare Co., CA .......................... 0.35

Total population ............. 7.76

Table III.C–2 is limited to designated

PM10 nonattainment areas which both

had monitored violations of the PM10

NAAQs in 1996–1998 and are predicted

to be in nonattainment in 2030 in our

PM10 air quality modeling. This gives us

high confidence that these areas require

further emission reductions to attain

and maintain, but does not fully

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6719

33 In fact, in two of these areas, New York Co.,

NY and Harris Co., TX, the average PM10 level in

1998 was above the 50 μg/m3 value of the NAAQS.

These two areas are not included in the Table III.C–

2 list of areas with a high risk of failing to attain

and maintain because lower PM10 levels in 1996

and 1997 caused their three-year average PM10 level

to be lower than the NAAQS. Official

nonattainment determinations for the annual PM10

NAAQS are made based on the average of 12

quarterly PM10 averages.

consider the possibility that there are

other areas which are now meeting the

PM10 NAAQS which have at least a

significant probability of requiring

further reductions to continue to

maintain it. Our air quality modeling

predicted 2030 violations of the annual

average PM10 NAAQS in five additional

counties that in either 1997 or 1998 had

single-year annual average monitored

PM10 levels of at least 90 percent of the

NAAQS, but did not exceed the formal

definition of the NAAQS over the threeyear period ending in 1998 33. These

areas are shown in Table III.C–3. They

have a combined population of almost

17 million, and a broad geographic

spread. Unlike the situation for ozone,

for which precursor emissions are

generally declining over the next 10

years or so before beginning to increase,

we estimate that emissions of PM10 will

rise steadily unless new controls are

implemented. The small margin of

attainment which these areas currently

enjoy will likely erode; the PM air

quality modeling suggests that it will be

reversed. We therefore consider these

areas to each individually have a

significant risk of failing to maintain the

NAAQS without further emission

reductions. There is a substantial risk

that at least some of them would fail to

maintain without further emission

reductions. The emission reductions

from the Tier 2/Gasoline Sulfur program

will help to keep them in attainment.

TABLE III.C–3.—FIVE AREAS WITH A

SIGNIFICANT RISK OF FAILING TO

ATTAIN AND MAINTAIN THE PM10

NAAQS WITHOUT FURTHER REDUCTIONS IN EMISSIONS

Area

1996

population

(millions)

New York Co., NY .................... 1.33

Cuyahoga Co., OH ................... 1.39

Harris, Co., TX .......................... 3.10

San Diego Co., CA ................... 2.67

Los Angeles Co., CA ................ 8.11

Total population ............. 16.6

Taken together and considering their

number, size, and geographic

distribution, these 13 areas are sufficient

to establish the case that additional

reductions are needed in order to attain

and maintain the PM10 NAAQS. This

determination provides additional

support for the NOx and VOC standards

and for the limits on gasoline sulfur,

which are also fully supported on ozone

attainment and health effects

considerations. The sulfate particulate,

sulfur dioxide, NOX, and VOC emission

reductions from the Tier 2/Gasoline

Sulfur program will help the 8 areas in

Table III.C–2 and the 5 areas in Table

III.C.–3 to attain and maintain the PM10

NAAQS. The new PM standards for

gasoline and diesel vehicles are also

supported by this PM10 determination.

We are also establishing the new PM

emissions standard today to avoid the

possibility that PM10 concentrations in

these and other areas do get even worse

due to an increase in sales of diesel

vehicles, which could create a need for

further reductions which would be

larger and would affect more areas of

the country. At the present time,

virtually all cars and light trucks being

sold are gasoline fueled. The ambient

PM10 air quality data for 1996 to 1998

reflects that current situation, and this

data was an important factor in what

areas are listed in Tables III.C–2 and

III.C–3. Also, the predictions of future

PM10 air quality, used to develop the

Tables III.C–2 and III.C–3 lists of areas

with high or significant risk of being

unable to attain and maintain, are based

on an assumption that this will continue

to be true. However, we are concerned

over the possibility that diesels will

become more prevalent in the car and

light-duty truck fleet, since automotive

companies have announced their desire

to increase their sales of diesel cars and

light trucks. Because current diesel

vehicles emit higher levels of PM10 than

gasoline vehicles, a larger number of

diesel vehicles could dramatically

increase levels of exhaust PM10,

especially if more stringent PM

emissions standards are not in place.

The new PM emissions standards will

ensure that an increase in the sales of

diesel cars and light trucks will not

increase PM emissions from cars and

light trucks so substantially as to

endanger PM10 attainment and

maintenance on a more widespread

basis. Given this potential, it is

appropriate to establish the new PM

emissions standards now on the basis of

the increase in sales of diesel vehicles

being a reasonable possibility without

such standards. Establishing the new

PM emissions standards now avoids the

public health impact and industry

disruption that could result if we waited

until an increase in sales of diesels with

high PM emissions had already

occurred.

In order to assess the potential impact

of increased diesel sales penetration on

PM emissions, we analyzed the increase

in PM10 emissions from cars and trucks

under a scenario in which the use of

diesel engines in cars and light trucks

increases. We used projections

developed by A.D. Little, Inc. as part of

a study conducted for the American

Petroleum Institute. The ‘‘Most Likely’’

case projected by A.D. Little forecasts

that diesel engines’’ share of the light

truck market will grow to 24 percent by

the 2015 model year. Diesel engines’

share of the car market would grow

somewhat more slowly, reaching 9

percent by 2015. The A.D. Little

forecasts did not address the period

after 2015; we have assumed that diesel

sales stabilize at the level reached in

2015, with the fraction of in-use

vehicles with diesel engines continuing

to increase through turnover. We believe

these projections are more realistic than

the scenario of even higher sales of

diesels described in the notice for the

proposed Tier 2/Gasoline Sulfur

program, though the A.D. Little forecasts

still show much higher percentages of

diesel vehicles in the light-duty fleet

than have ever existed historically in

the U.S.

The A.D. Little scenario of increased

diesels, and even more so the scenario

described in our proposal, would result

in dramatic increases in direct PM10

emissions from cars and light trucks, if

there were no change in these vehicles’

PM standards. The increase in diesel

exhaust PM10 emissions would more

than overcome the reduction in direct

PM10 attributable to the sulfur reduction

in gasoline. With no change in the

existing PM standards for cars and light

trucks, our analysis of this scenario

shows that direct PM10 emissions in

2020 would be approximately 98,000

tons per year, which is nearly two times

the 50,000 tons projected if diesel sales

do not increase. The portion of ambient

PM10 concentrations attributable to cars

and light trucks would climb steadily.

The final RIA presents alternative

estimates of the amount by which future

PM10 concentrations could increase due

to such an emissions increase, based on

extrapolations from several studies’

estimates of the contribution that heavyduty diesel vehicles have made to recent

or PM10 concentrations. The increase is

estimated to range from 0.6 to 20 μg/m3.

The added PM10 emissions from cars

and trucks due to an increase in diesel

sales without action to reduce PM10

from new diesel vehicles would

exacerbate the PM10 nonattainment

problems of the areas listed in Tables

6720 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

III.C–2 and III.C–3, for which our air

quality modeling predicted future

nonattainment even without an increase

in diesel sales. Moreover, it might cause

PM10 nonattainment in additional areas.

In addition to the counties already listed

in Tables III.C–2 and III.C–3, there are

other areas for which 1997 and 1998

data indicate that maintenance of the

PM10 NAAQS is at risk if diesel sales of

cars and light truck increase. Table

III.C–4 lists additional counties for

which either 1997 or 1998 monitoring

data, or both, indicated a second-high

PM10 concentration for the single year

within 10 percent of the PM10 24-hour

NAAQS or an annual average PM10

concentration within 10 percent of the

annual average PM10 NAAQS. Only

counties which are part of metropolitan

statistical areas are listed in Table III.C–

4, in order to focus on those in which

traffic densities are high. Considering

both the annual and 24-hour NAAQS,

there were 13 areas within 10 percent of

the standard. Increases in PM10

emissions from more diesel vehicles

would put these areas in greater risk of

violating the PM10 NAAQS, especially if

growth in other sources is high or

meteorological conditions are more

adverse than in the 1996 to 1998 period.

TABLE III.C–4.—THIRTEEN METROPOLITAN STATISTICAL AREA COUNTIES WITH 1997 AND/OR

1998 AMBIENT PM10 Concentrations Within

10 Percent of the Annual or 24-Hour the

PM10 NAAQSa

1996

population

(millions)

Areas within 10 percent of the annual PM10

NAAQS:

Lexington Co., SC ........................... 0.20

Union Co., TN ................................. 0.02

Washoe Co., NV ............................. 0.30

Madison Co., IL ............................... 0.26

Dona Ana Co., NM .......................... 0.16

El Paso Co., TX .............................. 0.68

Ellis Co., TX .................................... 0.97

Fresno Co., CA ............................... 0.74

Philadelphia Co., PA ....................... 1.47

Areas within 10 percent of the 24-hour PM10

NAAQS:

Lexington Co., SC ........................... 0.20

El Paso Co., TX .............................. 0.68

Union Co., TN ................................. 0.02

Mobile Co., AL ................................ 0.40

Dona Ana Co., NM .......................... 0.16

Lake Co., IN .................................... 0.48

Philadelphia Co., PA ....................... 1.47

Pennington Co., SD ........................ 0.09

Ventura Co., CA .............................. 0.71

Total Population of all 13

areas ................................. 6.48

Notes:

aThese areas are listed based on their second

high 24-hour concentration and annual average concentration in 1997, 1998, or both. Official nonattainment determinations are made based on three years

of data, and on estimates of expected exceedances

of the 24-hour standard.

Fortunately, the standards included in

today’s actions will result in a steady

decrease in total direct PM10 from cars

and light trucks even if this increase in

the use of diesel engines in these

vehicles were to occur. If the A.D. Little

‘‘Most Likely’’ scenario for increased

diesel engines in light trucks were to

occur, today’s actions would reduce

diesel PM10 from cars and light trucks

by over 75 percent in 2020. Stated

differently, by 2030 today’s actions

would reduce 98,000 tons of the

potential increase in PM10 emissions

from passenger cars and light trucks.

The result would be less direct PM10

than is emitted today, because the

increase in diesel PM10 would be more

than offset by the reduction in PM10

emissions from gasoline vehicles

resulting from lower gasoline sulfur

levels.

We are establishing tighter PM

standards for cars and light trucks to

help avoid the adverse impact of greater

diesel PM emissions on PM10 attainment

and public health and welfare if diesel

sales increased in the future without the

protection of the tighter standards.

Because diesel vehicles will essentially

be performing the same functions as the

gasoline vehicles they will replace, it is

appropriate for the new PM standards to

also apply equally to gasoline and diesel

vehicles. We expect that gasoline

vehicles will need little or no redesign

to meet the new PM standards when

free of defects and properly operating.

However, the new vehicle and gasoline

sulfur standards may achieve some

reduction in real world PM emissions

from gasoline vehicles by encouraging

more durable designs and by ensuring

that these vehicles are operated on

lower-sulfur fuel. The new standards for

PM will also prevent any changes in

gasoline engine design which would

increase PM emissions. These changes

would otherwise be possible because

the current PM standard is so much

higher than the current performance on

the gasoline vehicles.

3. PM2.5 Discussion

We are not basing our promulgation of

the Tier 2 vehicle standards on a finding

on the need for additional emission

reductions in order to attain and

maintain the NAAQS for PM2.5. We are

providing this information to explain

that this program will result in

substantial benefit in reduction of PM2.5

concentrations, to an even broader set of

geographic areas than will benefit in

terms of PM10 attainment.

The annual and 24-hour PM2.5

NAAQS set in 1997 are numerically

much lower than the corresponding

PM10 standards: 15 versus 50 μg/m3 for

the annual average standards and 65

versus 150 μg/m3 for the 24-hour

average standards. While geographically

broad PM2.5 monitoring is just now

reaching the end of the first of three

years of operation needed to determine

compliance, our best analysis from the

more limited PM2.5 conducted in some

areas indicates that many areas that are

in compliance with the PM10 standards

will be found to be in violation of the

annual average PM2.5 standard.

Violations of the 24-hour PM2.5 standard

appear to be infrequent.

Therefore, if we considered it

appropriate to proceed with

implementing the PM2.5 NAAQS, we are

confident that there would be a larger

set of areas for which we would

determine that further reductions in

emissions are needed in order to attain

and maintain the NAAQS.

Moreover, gasoline and diesel cars

and light trucks have a more important

contributing role for ambient PM2.5

concentrations, and other emission

sources that play a major role in

ambient PM10 concentrations will be

relatively less important. Cars and light

trucks contribute essentially the same

absolute amount to ambient

concentrations of PM10 and of PM2.5.

However, most other sources contribute

much more to PM10 than to PM2.5, so the

relative contribution from cars and light

trucks is larger. In addition, the absolute

contribution from cars and light trucks

is larger in relationship to the

numerically lower PM2.5 standard,

making them more important to

attainment and maintenance. This is

also true for the potential contribution

that more diesel cars and light trucks

would make to ambient PM2.5

concentrations.

4. Emission Reductions and Ambient

PM Reductions

The NOX and VOC emission

reductions from the Tier 2/Gasoline

Sulfur program are presented in the

ozone section above. The SOX and PM

reductions are presented in our final

RIA, and are essentially unchanged from

those presented in our proposal, except

for the revision of the diesel sales

scenario discussed above.

Because virtually all of the PM

reduction from the Tier 2/Gasoline

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6721

34 ‘‘National Parks and the American Public: A

National Public Opinion Survey on the National

Park System,’’ Summary Report, National Parks and

Conservation Association, June 1998.

35 ‘‘Recommendations for Improving Western

Vistas,’’ Report of the Grand Canyon Visibility

Transport Commission to the United States

Environmental Protection Agency, June 10, 1996.

Sulfur program is in the fine fraction of

PM10, our estimates of the PM2.5 and

PM10 reductions are essentially the

same. Estimates of the ambient PM

reductions in 2030 in different parts of

the nation, after full phase in of the

vehicle standards, are presented in the

final RIA. The reductions in ambient

PM are largest in the parts of the

country with more vehicle travel, i.e,

larger in the east than in the west and

larger in urban areas than in rural areas.

In the eastern half of the nation, the

reductions in annual average PM

concentrations range from 0.2 to over

1.2 micrograms per cubic meter.

D. Other Criteria Pollutants: Carbon

Monoxide, Nitrogen Dioxide, Sulfur

Dioxide

The standards being promulgated

today will help reduce levels of three

other pollutants for which NAAQSs

have been established: carbon monoxide

(CO), nitrogen dioxide (NO2), and sulfur

dioxide (SO2). As of 1998, every area in

the United States has been designated to

be in attainment with the NO2 NAAQS.

As of 1997, one area (Buchanan County,

Missouri) did not meet the primary SO2

short-term standard, due to emissions

from the local power plant. There are

currently 20 designated CO

nonattainment areas, with a combined

population of 33 million. There are also

24 designated maintenance areas with a

combined population of 22 million.

However, the broad trends indicate that

ambient levels of CO are declining. In

1997, 6 of 537 monitoring sites reported

ambient CO levels in excess of the CO

NAAQS.

The reductions in SO2 precursor

emissions from today’s actions are

essentially equal to the SOX reductions

described in Section III.B. and III.C.,

respectively. The impact of today’s

actions on NO2 emissions depends on

the specific emission control

technologies used to meet the Tier 2

vehicle emission standards. However,

essentially all of the NOX emitted by

cars and light trucks converts to NO2 in

the atmosphere; therefore, it is

reasonable to assume that today’s

actions will substantially reduce

ambient NO2 levels by the same

proportion. Today’s rule also will

require light trucks to meet more

stringent CO standards. These more

stringent standards will help extend the

trend towards lower CO emissions from

motor vehicles and thereby help the

remaining CO nonattainment areas

reach attainment while helping other

areas remain in attainment with the CO

NAAQS. Our analysis of CO reductions

from today’s program is found in

Chapter III of the RIA. The analysis of

economic benefits and costs found in

Section IV.D.–5. does not account for

the economic benefits of the CO

reductions expected to result from

today’s proposal.

E. Visibility

Visibility impairment occurs as a

result of the scattering and absorption of

light by particles and gases in the

atmosphere. It is most simply described

as the haze that obscures the clarity,

color, texture, and form of what we see.

The principal cause of visibility

reduction is fine particles between 0.1

and 1 μm in size. Of the pollutant gases,

only NO2 absorbs significant amounts of

light; it is partly responsible for the

brownish cast of polluted skies. While

the contribution of NO2 to visibility

impairment varies from area to area, it

is generally responsible for less than ten

percent of visibility reduction.

The CAA requires EPA to protect

visibility, or visual air quality, through

a number of programs. These programs

include the national visibility program

under Sections 169a and 169b of the

Act, the Prevention of Significant

Deterioration program for the review of

potential impacts from new and

modified sources, and the secondary

NAAQS for PM10 and PM2.5. The

national visibility program established

in 1980 requires the protection of

visibility in 156 mandatory federal Class

I areas across the country (primarily

national parks and wilderness areas).

More than 65 million visitors travel

each year to these parks and wilderness

areas. The CAA established as a national

visibility goal, ‘‘the prevention of any

future, and the remedying of any

existing, impairment of visibility in

mandatory federal Class I areas in which

impairment results from manmade air

pollution.’’ The Act also calls for state

programs to make ‘‘reasonable progress’’

toward the national goal. In addition, a

recent national opinion poll on the state

of the national parks found that more

than 80 percent of Americans believe air

pollution affecting these parks should

be cleaned up for the benefit of future

generations.34

There has been improvement in

visibility in the western part of the

country over the last ten years.

However, visibility impairment remains

a serious problem in Class I areas.

Visibility in the East does not seem to

have improved. As one part of

addressing this national problem, EPA

has required states to adopt and

implement effective plans for protecting

and improving visibility in Class I

federal areas (64 FR 35714, July 1,

1999).

Today’s actions will result in

visibility improvements due to the

reduction in local and upwind PM and

PM precursor emissions. Since mobile

source emissions contribute to the

formation of visibility-reducing PM,

control programs that reduce the mobile

source emissions of direct and

secondary PM would have the effect of

improving visibility. The Grand Canyon

Visibility Transport Commission’s final

recommendations report 35 found that

reducing total mobile source emissions

is an essential part of any program to

protect visibility in the Western U.S.

The Commission found that motor

vehicle exhaust is responsible for about

14 percent of human-caused visibility

reduction (excluding road dust). A

substantial portion of motor vehicle

exhaust comes from cars and light

trucks. In light of that impact, the

Commission’s recommendations in 1996

supported federal Tier 2/Gasoline Sulfur

standards, as EPA is proposing today.

More recently, a number of Western

Governors noted the importance of

controlling mobile sources as part of

efforts to improve visibility in their

comments on the Regional Haze Rule

and on the need to protect the 16 Class

I areas on the Colorado Plateau. In their

joint letter dated June 29, 1998, they

stated that, ‘‘* * * the federal

government must do its part in

regulating emissions from mobile

sources that contribute to regional haze

in these areas. * * *’’ and called on

EPA to make a ‘‘binding commitment

* * * to fully consider the

Commission’s recommendations related

to the * * * federal national mobile

source emission control strategies.’’

These recommendations included Tier 2

vehicle standards and reductions in

gasoline sulfur levels.

The recent Northern Front Range Air

Quality Study provides another

indication of how important car and

light truck emissions can be to fine PM

and visibility. This study reported

findings that indicate that cars and light

trucks are responsible for 39 percent of

fine PM at a site within the metropolitan

Denver area, and for 40 percent at a

downwind rural site. This contribution

includes both direct PM and indirect

PM formed from sulfur dioxide and

NOX from these vehicles.

6722 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

36EPA’s diesel health assessment (Health

Assessment Document for Diesel Emissions, SAB

Review Draft, U.S. Environmental Protection

Agency, Washington, DC. EPA/600/8–90/057D,

November 1999) can be found at the following EPA

website: http://www.epa.gov/ncea/diesel.htm.

37National Institute for Occupational Safety and

Health (1988) Carcinogenic effects of exposure to

diesel exhaust. NIOSH Current Intelligence Bulletin

50. DHHS (NIOSH) Publication No. 88–116. Centers

for Disease Control, Atlanta, GA.

International Agency for Research on Cancer

(1989) Diesel and gasoline engine exhausts and

some nitroarenes, Vol. 46. Monographs on the

evaluation of carcinogenic risks to humans. World

Health Organization, International Agency for

Research on Cancer, Lyon, France.

World Health Organization (1996) Diesel fuel and

exhaust emissions: International program on

chemical safety. World Health Organization,

Geneva, Switzerland.

California Environmental Protection Agency,

Office of Environmental Health Hazard Assessment:

Proposed Identification of Diesel Exhaust as a Toxic

Air Contaminant, Part B Health Risk Assessment for

Diesel Exhaust. April 22, 1998.

38California Environmental Protection Agency,

Office of Environmental Health Hazard Assessment:

Proposed Identification of Diesel Exhaust as a Toxic

Air Contaminant, Part B Health Risk Assessment for

Diesel Exhaust. April 22, 1998.

39 ‘‘U.S. Light-Duty Dieselization Scenarios—

Preliminary Study’’, report to the American

Petroleum Institute, July 2, 1999. Prepared by

Arthur D. Little, Inc.

The analysis of economic benefits and

costs found in Section IV.D.5. accounts

for the economic benefits of the

visibility improvements expected to

result from today’s actions.

F. Air Toxics

Section 202(a) provides that EPA may

promulgate standards regulating any air

pollutants that in the Administrator’s

judgment, cause or contribute to air

pollution which may reasonably be

anticipated to endanger public health or

welfare. Section 202(l) provides specific

provisions for regulation of hazardous

air pollutants from motor vehicles and

fuels, and states that at a minimum such

regulations should apply to emissions of

benzene and formaldehyde.

Emissions from cars and light trucks

include a number of air pollutants that

are known or suspected human or

animal carcinogens or that are known or

suspected to have other, non-cancer

health impacts. These pollutants

include benzene, formaldehyde,

acetaldehyde, 1,3-butadiene, and diesel

particulate matter. For several of these

pollutants, motor vehicle emissions are

believed to account for a significant

proportion of total nation-wide

emissions. All of these compounds are

present in exhaust emissions; benzene is

also found in evaporative emissions

from gasoline-fueled vehicles.

The health effects of diesel particulate

matter are of particular relevance to

today’s actions, because of the

possibility for increased diesel-powered

truck sales and the more stringent PM

standard that will apply to these trucks

as a result of today’s actions. While we

have not finalized our decision about

the carcinogenicity of diesel exhaust, we

are in the process of addressing this

question. The Agency’s recently

released draft assessment 36 concludes

that diesel exhaust is a highly likely

human lung cancer hazard, but that the

data are currently unsuitable to make a

confident quantitative statement of risk.

The draft report concludes, however,

that this risk is applicable to ambient

exposures and that the risk may be in

the range of regulatory interest (greater

than one in a million over a lifetime).

Several other agencies and governing

bodies have designated diesel exhaust

or diesel PM as a ‘‘potential’’ or

‘‘probable’’ human carcinogen.37 The

California Air Resources Board (ARB),

for example, found that diesel

particulate matter constituted a toxic air

contaminant and estimated a potency

range of 1.3 × 10¥4 to 2.4 × 10¥3 per μg/

m3.38 The ARB’s findings suggest that

130 to 2400 persons in one million

exposed to 1 μg/m3 of diesel exhaust

particulate continuously for their

lifetime (70 years) would develop

cancer as a result of their exposure.

Because our assessment for diesel

exhaust is not complete, we are not

presenting absolute estimates of how

potential cancer risks from diesel

particulate matter could be affected by

today’s rule. However, we can offer a

qualitative or relative discussion of

these risks. Diesel engines used in

nonroad equipment and heavy-duty

highway vehicles currently constitute a

far larger source of diesel PM than cars

and light-duty trucks, since diesel

engines are used in a very small portion

of the cars and light-duty trucks in

service today. However, engine and

vehicle manufacturers have projected

that diesel engines are likely to be used

in an increasing share of cars and light

trucks, and some manufacturers have

announced capital investments to build

such engines.

If these projections are valid, then the

proportion of cars and light trucks

powered by diesel engines, and the

associated potential health risks from

diesel PM, could increase substantially.

We modeled the most likely level of

increase in light duty diesel engine sales

developed for the American Petroleum

Institute.39 We found that the greater

diesel engine usage in cars and light

trucks resulted in an 80 percent increase

in emissions from all diesel-powered

highway vehicles by 2020—emissions

that have been implicated in potential

cancer risks—assuming no change in the

current light-duty diesel PM standards.

Today’s rule would limit the increase

in the potential cancer risks from cars

and light trucks associated with any

potential increase in light-duty diesel

engines. Using the same sales

projections discussed above, we have

estimated that today’s rule would limit

the increase in total highway diesel PM

emissions in 2020 due to growth in light

duty diesels to under 10 percent, in

contrast to the 80 percent increase

projected to occur without the Tier 2

PM standards. An analogous analysis

that accounted for exposure patterns,

but that assumed even more widespread

use of diesels in the car and light truck

fleet, found that today’s rule would

limit the increase in total highway

diesel PM exposure to about 8 percent.

This analysis is discussed more fully in

Chapter III.F.2 of the Regulatory Impact

Analysis. In addition, the VOC emission

reductions resulting from today’s rule

would reduce the potential cancer risk

posed by air pollutants other than diesel

PM emitted by cars and light trucks,

since many of these pollutants are

themselves VOCs. Furthermore, the rule

would align the formaldehyde standards

for all Tier 2 LDVs and LDTs with the

formaldehyde standards for LDVs and

LDT1s from the NLEV program, thereby

helping to harmonize the Federal and

California formaldehyde standards.

The analysis of economic benefits and

costs found in Section IV.D.5. does not

account for the economic benefits of the

reduction in cancer risk from air toxics

that could result from today’s rule.

Although we have completed a peer

reviewed assessment of the impact of

today’s rule on exposure to toxic

emissions, we have not engaged in a

peer-reviewed assessment of the

baseline air toxics risks (including a

final quantitative risk assessment of the

diesel particulate risks) or of the

reductions that would be achieved by

today’s rule.

We plan to complete our analysis of

air toxics risks as part of our

responsibilities under section 202(l)(2)

of the Clean Air Act, which requires

EPA to establish regulations for the

control of hazardous air pollutants from

motor vehicles. The regulations may

address vehicle emissions or fuel

properties that influence emissions, or

both. We plan to issue a proposal to

address this requirement in April 2000,

and a final rule in December 2000.

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6723

40Much of the information in this section was

excerpted from the EPA document, Human Health

Benefits from Sulfate Reduction, written under Title

IV of the 1990 Clean Air Act. Amendments, U.S.

EPA, Office of Air and Radiation, Acid Rain

Division, Washington, DC, November 1995.

41 Vitousek, Peter M., John Aber, Robert W.

Howarth, Gene E. Likens, et al. 1997. Human

Alteration of the Global Nitrogen Cycle: Causes and

Consequences. Issues in Ecology. Published by

Ecological Society of America, Number 1, Spring

1997.

42Much of this information was taken from the

following EPA documenta: Deposition of Air

Pollutants to the Great Waters-Second Report to

Congress, Office of Air Quality Planning and

Standards, June 1997, EPA–453/R–97–011.

43Terrestrial nitrogen deposition can act as a

fertilizer. In some agricultural areas, this effect can

be beneficial.

G. Acid Deposition 40

Acid deposition, or acid rain as it is

commonly known, occurs when SO2

and NOX react in the atmosphere with

water, oxygen, and oxidants to form

various acidic compounds that later fall

to earth in the form of precipitation or

dry deposition of acidic particles. It

contributes to damage of trees at high

elevations and in extreme cases may

cause lakes and streams to become so

acidic that they cannot support aquatic

life. In addition, acid deposition

accelerates the decay of building

materials and paints, including

irreplaceable buildings, statues, and

sculptures that are part of our nation’s

cultural heritage. To reduce damage to

automotive paint caused by acid rain

and acidic dry deposition, some

manufacturers use acid-resistant paints,

at an average cost of $5 per vehicle—a

total of $61 million per year if applied

to all new cars and trucks sold in the

U.S. The general economic and

environmental effects of acid rain are

discussed at length in the RIA.

Acid deposition primarily affects

bodies of water that rest atop soil with

a limited ability to neutralize acidic

compounds. The National Surface Water

Survey (NSWS) investigated the effects

of acidic deposition in over 1,000 lakes

larger than 10 acres and in thousands of

miles of streams. It found that acid

deposition was the primary cause of

acidity in 75 percent of the acidic lakes

and about 50 percent of the acidic

streams, and that the areas most

sensitive to acid rain were the

Adirondacks, the mid-Appalachian

highlands, the upper Midwest and the

high elevation West. The NSWS found

that approximately 580 streams in the

Mid-Atlantic Coastal Plain are acidic

primarily due to acidic deposition.

Hundreds of the lakes in the

Adirondacks surveyed in the NSWS

have acidity levels incompatible with

the survival of sensitive fish species.

Many of the over 1,350 acidic streams

in the Mid-Atlantic Highlands (midAppalachia) region have already

experienced trout losses due to

increased stream acidity. Emissions

from U.S. sources contribute to acidic

deposition in eastern Canada, where the

Canadian government has estimated that

14,000 lakes are acidic. Acid deposition

also has been implicated in contributing

to degradation of high-elevation spruce

forests that populate the ridges of the

Appalachian Mountains from Maine to

Georgia. This area includes national

parks such as the Shenandoah and Great

Smoky Mountain National Parks.

The SOX and NOX reductions from

today’s actions will help reduce acid

rain and acid deposition, thereby

helping to reduce acidity levels in lakes

and streams throughout the U.S. These

reductions will help accelerate the

recovery of acidified lakes and streams

and the revival of ecosystems adversely

affected by acid deposition. Reduced

acid deposition levels will also help

reduce stress on forests, thereby

accelerating reforestation efforts and

improving timber production.

Deterioration of our historic buildings

and monuments, and of buildings,

vehicles, and other structures exposed

to acid rain and dry acid deposition,

also will be reduced, and the costs

borne to prevent acid-related damage

may also decline.

While the reduction in sulfur and

nitrogen acid deposition will be roughly

proportional to the reduction in SOX

and NOX emissions, respectively, the

precise impact of today’s vehicle and

fuel standards will differ across

different areas. Each area is affected by

emissions from different source regions,

and the mobile source contribution to

the total SOX and NOX emission

inventory will differ across different

source regions. Nonetheless, the

projected impact of today’s actions on

SOX and NOX emission inventories

provides a rough indicator of the likely

effect of the Tier 2/Gasoline Sulfur

standards on acid deposition. Our

analysis indicates that today’s actions

will reduce SOX emissions by 1.8

percent and NOX emissions by 14.5

percent in 2030.

The analysis of economic benefits and

costs found in Section IV.D.5. did not

account for the economic benefits of the

reduction in acid deposition expected to

result from today’s actions.

H. Eutrophication/Nitrification

Nitrogen deposition into bodies of

water can cause problems beyond those

associated with acid rain. The

Ecological Society of America has

included discussion of the contribution

of air emissions to increasing nitrogen

levels in surface waters in a recent

major review of causes and

consequences of human alteration of the

global nitrogen cycle in its Issues in

Ecology series 41. Long-term monitoring

in the United States, Europe, and other

developed regions of the world shows a

substantial rise of nitrogen levels in

surface waters, which are highly

correlated with human-generated inputs

of nitrogen to their watersheds. These

nitrogen inputs are dominated by

fertilizers and atmospheric deposition.

Human activity can increase the flow

of nutrients into those waters and result

in excess algae and plant growth. This

increased growth can cause numerous

adverse ecological effects and economic

impacts, including nuisance algal

blooms, dieback of underwater plants

due to reduced light penetration, and

toxic plankton blooms. Algal and

plankton blooms can also reduce the

level of dissolved oxygen, which can

also adversely affect fish and shellfish

populations. This problem is of

particular concern in coastal areas with

poor or stratified circulation patterns,

such as the Chesapeake Bay, Long

Island Sound, or the Gulf of Mexico. In

such areas, the ‘‘overproduced’’ algae

tends to sink to the bottom and decay,

using all or most of the available oxygen

and thereby reducing or eliminating

populations of bottom-feeder fish and

shellfish, distorting the normal

population balance between different

aquatic organisms, and in extreme cases

causing dramatic fish kills.

Collectively, these effects are referred

to as eutrophication, which the National

Research Council recently identified as

the most serious pollution problem

facing the estuarine waters of the United

States (NRC, 1993). Nitrogen is the

primary cause of eutrophication in most

coastal waters and estuaries 42. On the

New England coast, for example, the

number of red and brown tides and

shellfish problems from nuisance and

toxic plankton blooms have increased

over the past two decades, a

development thought to be linked to

increased nitrogen loadings in coastal

waters. Airborne NOX contributes from

12 to 44 percent of the total nitrogen

loadings to United States coastal water

bodies. For example, approximately

one-quarter of the nitrogen in the

Chesapeake Bay comes from

atmospheric deposition.

Excessive fertilization with nitrogencontaining compounds can also affect

terrestrial ecosystems 43. Research

suggests that nitrogen fertilization can

alter growth patterns and change the

6724 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

balance of species in an ecosystem. In

extreme cases, this process can result in

nitrogen saturation when additions of

nitrogen to soil over time exceed the

capacity of the plants and

microorganisms to utilize and retain the

nitrogen. This phenomenon has already

occurred in some areas of the U.S.

Deposition of nitrogen from cars and

light trucks contributes to these

problems. As discussed in Section III.B.

above, today’s actions will reduce total

NOX emissions by 4.5 percent in 2007

and by 14.5 percent in 2030. The NOX

reductions should reduce the

eutrophication problems associated

with atmospheric deposition of nitrogen

into watersheds and onto bodies of

water, particularly in aquatic systems

where atmospheric deposition of

nitrogen represents a significant portion

of total nitrogen loadings. Since air

deposition accounts for 12–44 percent

of total nitrogen loadings in coastal

waters, the reduction in NOX from

today’s actions is projected to reduce

nitrogen loadings by 0.5–2.0 percent in

2007 and 1.7–6.4 percent in 2030. To

put these reductions in perspective, the

reductions expected in the Chesapeake

Bay area would amount to about 9

percent of the total reduction in

nitrogen loading needed to maintain the

reduction in nutrient loads agreed to by

the signatory states in the Chesapeake

Bay Agreement (40 percent of

‘‘controllable nutrient loads’’ by the year

2000).

The analysis of economic benefits and

costs found in Section IV.D.5. does not

account for the economic benefits of

reduced eutrophication or reduced

terrestrial nitrogen deposition expected

to result from today’s actions.

I. Cleaner Cars and Light Trucks Are

Critically Important to Improving Air

Quality

Despite continued progress in

reducing ozone and PM levels, tens of

millions of Americans are still exposed

to levels of these pollutants that exceed

the National Ambient Air Quality

Standards. Our projections show that

without further action to reduce these

pollutants, tens of millions of

Americans will continue to breathe

unhealthy air for decades to come. Our

projections also show that emissions

from cars and light trucks will continue

to contribute a substantial share of the

ozone and PM precursors in current and

projected nonattainment areas, and in

upwind areas whose emissions

contribute to downwind nonattainment,

unless additional measures are taken to

reduce their emissions. Cars and light

trucks also contribute substantially to

ambient concentrations of CO. These

vehicles will also continue to contribute

to the ambient PM that affects visibility

in Class I federal areas and some urban

areas. Emissions from cars and light

trucks also play a significant role in a

wide range of health and environmental

problems, including known and

potential cancer risks from inhalation of

air pollutants (a problem that could

become more significant if sales of

diesel-powered cars and light trucks

were to increase), health risks from

elevated drinking water nitrate levels,

acidification of lakes and streams, and

eutrophication of inland and coastal

waters.

Today’s actions will reduce NOX,

VOC, CO, PM, and SOX emissions from

these vehicles substantially. These

reductions will help reduce ozone levels

nationwide and reduce the extent and

severity of violations of the 1-hour

ozone standard. These reductions will

also help reduce PM levels, both by

reducing direct PM emissions and by

reducing emissions that give rise to

secondary PM. The CO reductions will

help extend the downward trend in

carbon monoxide levels, thereby

helping the remaining CO

nonattainment areas attain the CO

standard and helping other areas stay in

attainment with the CO standard despite

continued increases in vehicle miles

traveled. The NOX and SOX reductions

will help reduce acidification problems,

and the NOX reductions will help

reduce eutrophication problems and

drinking water nitrate levels. The PM

standards included in today’s actions

will help improve visibility and would

help mitigate adverse health effects in

the event of increases in light-duty

diesel engine sales.

IV. What Are the New Requirements for

Vehicles and Gasoline?

A. Why Are We Proposing Vehicle and

Fuel Standards Together?

1. Feasibility of Stringent Standards for

Light-Duty Vehicles and Light-Duty

Trucks.

a. Gasoline Fueled Vehicles

We believe that the standards being

promulgated today for gasoline-fueled

vehicles are well within the reach of

existing control technology. Our

determination of feasibility is based on

the use of catalyst-based strategies that

are already in use and are well proven

on the existing fleet of vehicles. In fact,

as you will see below, many current

engine families are already certified to

levels at or below the new final Tier 2

requirements. All of the certification

and research testing discussed below

was performed on low-sulfur test fuel

(nominally 30 ppm).

i. LDVs and LDT1s–LDT4s

Certainly, larger vehicles and trucks,

which are heavier and have larger

frontal areas, will face the biggest

challenges in meeting the final Tier 2

standards. However, conventional

technology will be sufficient for even

these vehicles, especially in light of the

extra leadtime we have provided before

LDT3s and LDT4s have to meet Tier 2

levels. We are also changing the test

conditions for these trucks from

‘‘adjusted loaded vehicle weight’’ to

‘‘loaded vehicle weight.’’ Adjusted

loaded vehicle weight, suitable for

commercial truck operation, loads the

truck to half of its full payload. Loaded

vehicle weight, on the other hand,

represents curb weight plus 300 pounds.

This change more accurately reflects

how these vehicles are used and makes

heavy LDT testing consistent with

passenger car and light LDT testing.

This change is consistent with treating

these vehicles as they were designed,

i.e., for light-load use.

Emission control technology has

evolved rapidly in recent years.

Emission standards applicable to 1990

model year vehicles required roughly 90

percent reductions in exhaust HC and

CO emissions and a 75 percent

reduction in NOX emissions compared

to uncontrolled emissions. Today, some

vehicles currently in production are

well below these levels, showing even

greater overall emissions reductions of

all three of these pollutants. These

vehicles’ emissions are well below those

necessary to meet the current federal

Tier 1 and even California LowEmission Vehicle (LEV–I) standards.

The reductions have been brought about

by ongoing improvements in engine airfuel management hardware and software

plus improvements in catalyst designs,

all of which are described fully in the

RIA.

The types of changes being seen on

current vehicles have not yet reached

their technological limits, and

continuing improvement will allow

both LDVs and LDTs to meet the final

standards. The RIA describes a range of

specific techniques that we believe

could be used. These range from

improved computer software and engine

air-fuel controls to increases in precious

metal loading and other exhaust system/

catalyst system improvements. All of

these technologies are currently used on

one or more production vehicle models.

There is no need to invent new

approaches or technologies. The focus

of the effort is primarily development,

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6725

44Powertrain control modules are computers

used to control engine, transmission, and other

vehicle functions on newer automobiles and trucks.

The changes involved software changes in the case

of the EPA-NVFEL work, or the use of alternate

means of engine control in the case of the SwRI

work.

45Although this testing was done on vehicles

with catalysts aged to 50,000, we belive the overall

experiments also strongly suggest that the Tier 2

full-life standards would be achieved by highmileage vehicles.

application, and optimization of these

existing technologies.

We can gain significant insight into

the difficulty of meeting the final new

standards by looking at current full-life

certification data. There are at least 48

engine family-control systems

combinations, out of approximately 400,

certified in 1999 at levels below the Tier

2 NOX standard of 0.07 g/mi. Of these,

35 also have hydrocarbon levels of 0.09

g/mi or below. Looking at a somewhat

higher threshold to identify vehicles

certified near the final standard, there

are an additional 113 car and light truck

families certified at levels between 0.07

g/mi and 0.10 g/mi NOX. Although not

yet complete at this time, we also

examined the 2000 model year

certification data and found that there

are at least 60 engine family-control

systems combinations certified at levels

below the Tier 2 NOX standard of 0.07

g/mi and of those, 52 also have

hydrocarbon levels of 0.09 g/mi or

below.

All of the above vehicles are already

able, or close to being able, to certify to

our final standards. The further

reductions needed are those to provide

a compliance margin, or cushion,

between the certified level and the

emission standard. The degree of

compliance margin required is a

function of a variety of factors designed

to provide the manufacturer a high

confidence that production vehicles will

meet the standards in-use over their

useful life. Historically, these

determinations are manufacturer

specific, with cushions generally

growing smaller as standards decline

(reflecting more precision and

repeatability in vehicle performance as

more sophisticated controls are

developed). The certification data

reflects compliance cushions from as

little as 20 percent below the standard

to as high as 80 percent below the

standard.

The manufacturers commented that

the most difficult vehicles to bring into

compliance with the Tier 2 standards

would be the larger light-duty trucks,

specifically those trucks currently

certified under the LDT3 and LDT4

weight categories. Because of this, we

undertook a technology demonstration

program aimed at lowering the

emissions of several large 1999 lightduty trucks. Two LDT3 Chevrolet

Silverado pick-up trucks were tested,

one internally and one under contract.

Two LDT4 Ford Expedition sport-utility

vehicles were also tested, also with one

tested internally and one under

contract. Both types of vehicles were

tested with optional high horsepower

engines (270 hp for the Silverado and

230 hp for the Expedition) and were

equipped with four-wheel drive. The

vehicles had curb weights of 4,500

pounds (GVWR of 6,100 lbs) for the

Silverados and 5,800 pounds (GVWR of

7,200 lbs) for the Expeditions.

Figures IV.A.–1 and IV.A.–2 show the

results to date of the emissions tests

performed during this demonstration

program at our National Vehicle and

Fuel Emissions Laboratory (NVFEL) and

also for emissions tests conducted in

parallel by and under contract at

Southwest Research Institute (SwRI)

using similar Ford Expeditions and GM

Chevrolet Silverados. During the

evaluation, the trucks were equipped

with a variety of catalysts that typically

featured higher volume, higher precious

metal loading, and higher cell-densities

than the original hardware used by the

vehicles to meet California LEV–I

standards. Details of the catalysts tested

are included in the RIA. Different

exhaust manifolds featuring an

insulating air-gap and low thermal mass

were also evaluated. Finally, calibration

changes were made to the powertrain

control modules 44 to better match

engine operating characteristics to the

new catalyst systems, and to lower

engine-out NOx emissions. The

Silverado and Expedition had very

similar results. Similar results were also

achieved by us and SwRI, but by fairly

different methods. The SwRI work on

both trucks relied primarily on engine

calibration changes and secondary air

injection. The advanced catalyst

systems used by SwRI contained

advanced washcoat formulations with

only minor changes to catalyst volume

and precious metal content compared to

the manufacturer’s original

configuration. The work we conducted

on the Expedition also relied primarily

on engine calibration changes with no

secondary air injection. The catalyst

system also contained advanced

washcoat formulations with modest

changes to catalyst volume and precious

metal content. The work we conducted

on the Silverado relied primarily on an

advanced catalyst system with volume

and precious metal content changes,

with only minor changes to engine

calibration.

As can be seen in the charts, the

emissions of the vehicles tested clearly

show the feasibility of the Tier 2

standards on the most difficult to certify

vehicle categories. All vehicles reached

emission levels well below the Tier 2

full-life NOx and NMOG standards. At

the same time, there were no significant

impacts on either fuel economy or

performance of the vehicles.

Compared to the intermediate (50,000

mile) standards, the Ford Expedition

tested at NVFEL consistently emitted

NOx at less than one-third of the

intermediate useful life standard.45

NMHC/NMOG emissions were slightly

below the intermediate standard level

with no use of secondary-air-injection

for cold-start hydrocarbon control. The

Silverado tested at NVFEL met the

intermediate standards with primarily

hardware (catalyst) changes and only

very minor calibration changes. The

trucks tested at SwRI differed from

those tested at NVFEL in their

combination of emissions control

hardware and calibration strategies, but

achieved approximately the same

emissions levels.

The above results point out that not

only are the Tier 2 standards feasible for

larger trucks, but there are multiple

means that can be taken in order to

achieve the necessary emissions levels.

All of those paths involve fairly simple

enhancements to current technology

systems. Furthermore, the testing was

conducted with a very limited budget

over a limited amount of time. With the

interim program for heavy trucks under

Tier 2, the manufacturers will have 9

years from the publishing of the Tier 2

rule to bring the largest trucks into

compliance with the Tier 2 standards.

Manufacturers will also have

considerably more resources with

respect to calibration changes and

hardware design to bring trucks of this

type within compliance than were

available within this limited, but

successful, demonstration.

BILLING CODE 6560–50–P

6726 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6727

BILLING CODE 6560–50–C

The Manufacturers of Emission

Controls Association (MECA) sponsored

a program that took two LDVs (a Crown

Victoria and a Buick LeSabre) and one

LDT2 (a Toyota T100) certified to the

federal Tier 1 standards and replaced

the original catalytic converter systems

with more advanced catalytic

converters, thermally aged to

approximately 50,000 miles. With these

systems and some related emission

control modifications, the LeSabre and

T100 emissions were well below our

intermediate (50,000 mile) useful life

standards, and the Crown Victoria was

well below the NMOG standard and

very close to the NOX standard.

Finally, the California Air Resources

Board (ARB) tested five different

production LEV light-duty vehicle

models. Three of the five models met

the Tier 2 standards for NMOG and NOX

prior to any modifications. After

installing low mileage advanced

catalytic converters and making some

minor adjustments to fuel bias, air

injection, and spark timing, all of the

vehicles had emission levels well below

the Tier 2 intermediate useful life

NMOG and NOX standards. ARB also

tested several Ford Expeditions (LDT4)

equipped with advanced catalytic

converters. By adjusting several

parameters, they were able to reduce

NOX emissions to 0.06 g/mi and NMOG

to 0.07 g/mi with a catalyst aged to

50,000 miles of use.

A more expanded analysis of the

feasibility of the Tier 2 standards for

gasoline fueled vehicles can be found in

the RIA, considering the types of

changes that will allow manufacturers

to extend effective new controls to the

entire fleet of affected vehicles. That

analysis includes discussion of gasoline

direct-injection engines, as well as the

feasibility of the CO, formaldehyde and

evaporative emission standards. The

conclusion of all of our analyses is that

the standards are feasible for gasolinefueled vehicles. As gasoline-fueled

vehicles represent the overwhelming

majority of the LDV and LDT population

(i.e., over 99%), EPA concludes that the

Tier 2 standards are feasible overall for

LDVs and LDTs under 8500 lbs GVWR.

ii. Medium-Duty Passenger Vehicles

(MDPVs)

The technologies and emission

control strategies that will be used for

LDT3 and LDT4 vehicles with a GVWR

less than 8,500 pounds should apply

directly to MDPV vehicles that have a

GVWR greater than 8,500 pounds. In our

LDT technology demonstration program

discussed above, we found that a

combination of calibration changes and

improvements to the catalyst system

resulted in emission levels for NOX well

below and NMHC/NMOG

approximately at the Tier 2 intermediate

useful life standards. The catalyst

improvements consisted of increases in

volume and precious metal loading, and

higher cell-densities than those found in

the original hardware. We are confident

that the use of secondary-air-injection

will greatly help cold-start hydrocarbon

control, making the NMOG standards

achievable.

The most significant difference

between LDT4s less than 8,500 pounds

GVWR and MDPVs greater than 8,500

pounds GVWR is that MDPVs have a

vehicle weight up to 800 pounds more

than LDT4s. MDPVs will also be

typically equipped with larger

displacement engines. The potential

impact of these differences is higher

engine-out emissions than LDT4s due to

the larger engine displacement and

6728 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

46 ‘‘Cummins Sees Diesel Feasible for Early Years

of Tier 2’’. Hart Diesel Fuel News, Sept. 20, 1999,

p.2. 47Harts Diesel Fuel News, August 9, 1999, p4.

greater load that the engine will be

operated under due to the extra weight.

However, neither of these preclude

manufacturers from applying the same

basic emission control technologies and

strategies as used by LDVs and LDTs.

The only difference will likely be the

need for larger catalysts with higher

precious metal loading than found in

LDT4s. We are confident that MDPVs

will be capable of meeting the final Tier

2 standards.

We are currently testing a Ford

Excursion as part of our LDT technology

demonstration program. Preliminary

baseline results with a ‘green’’ (i.e.,

nearly new) catalyst indicate that

emission levels are higher than baseline

emissions for the Ford Expedition.

These results, although with a green

catalyst, are well below our interim Tier

2 upper bin standards. In fact, the

majority of these vehicles certified on

the chassis dynamometer in California

have certification levels well below our

interim upper bin standards. While this

testing is ongoing, we feel that the

preliminary results are encouraging

since they suggest that the difference in

emissions between the Excursion and

Expedition suggest that the strategies

used on the Expedition can be

successful with the Excursion.

Therefore, we believe that by using

technologies and control strategies

similar to what will be used by LDVs

and LDTs, combined with larger

catalysts, MDPVs will be able to meet

our Tier 2 emission standards.

b. Diesel Vehicles

As discussed above, the Tier 2

standards are intended to be ‘‘fuel

neutral.’’ In today’s document, we

establish that the Tier 2 standards are

technologically feasible and costeffective for LDVs and LDTs overall,

based on the discussion in Section

IV.A.1.a. above. Under the principle of

fuel neutrality, all cars and light trucks,

including those using diesel engines,

will be required to meet the Tier 2

standards. Contrary to some of the

comments received on our proposal,

given that the overwhelming majority of

vehicles in these classes are gasolinefueled, we do not believe it is

appropriate to provide less stringent

standards for diesel-fueled vehicles.

Manufacturers of LDVs and LDTs today

provide consumers with a wide choice

of vehicles that are overwhelmingly

gasoline-fueled. Less stringent standards

for diesels would create provisions that

could undermine the emission

reductions expected from this program,

especially given the expectation that

some manufacturers may intend to

greatly increase their diesel sales.

As with gasoline engines,

manufacturers of diesels have made

abundant progress over the past 10 years

in reducing engine-out emissions from

diesel engines. In heavy trucks and

buses, PM emission standards, which

were projected to require the use of

exhaust aftertreatment devices, were

actually met with only engine

modifications. Indeed, emissions and

performance of lighter diesel engine are

rapidly approaching the characteristics

of gasoline engines, while retaining the

durability and fuel economy advantages

that diesels enjoy. Against this

background of continuing progress, we

believe that the technological

improvements that would be needed

could be made in the time that would

be available before diesels would have

to meet the new Tier 2 standards.

Manufacturers may take advantage of

the flexibilities in today’s rulemaking to

delay the need for diesel LDVs and

LDTs to meet the final Tier 2 levels until

late in the phase-in period (as late as

2007 for LDVs/LLDTs and 2009 for

HLDTs), giving manufacturers a

relatively large amount of leadtime. In a

recent public statement, Cummins

Engine Company has indicated that the

interim Tier 2 standards in effect for

vehicles and trucks in the early years of

the Tier 2 program are feasible for diesel

equipped models through further

development of currently available

engine and exhaust aftertreatment

technology.46

While reductions in ‘‘engine-out’’

emissions, including incorporation of

EGR strategies, may continue to be

made, increasing emphasis is being

placed on various aftertreatment devices

for diesels. We believe that the use of

aftertreatment devices will allow diesels

to comply with the Tier 2 standards for

NOX and PM.

For NOX emissions, potential

aftertreatment technologies include lean

NOX catalysts, NOX adsorbers and

selective catalytic reduction (SCR). Lean

NOX catalysts are still under

development, but generally appear

capable of reducing NOX emissions by

about 15–30%. This efficiency is not

likely to be sufficient to enable

compliance with the final Tier 2

standards, but it could be used to meet

the interim standards that would begin

in 2004, with current diesel fuel.

NOX adsorbers appear capable of

reaching efficiency levels as high as

90%. Efficiency in this range is likely to

be sufficient to enable compliance with

the proposed Tier 2 standards. NOX

adsorbers temporarily store the NOX and

thus the engine must be run periodically

for a brief time with excess fuel, so that

the stored NOX can be released and

converted to nitrogen and oxygen using

a conventional three-way catalyst, like

that used on current gasoline vehicles.

There is currently a substantial

amount of development work being

directed at NOX adsorber technology.

While there are technical hurdles to be

overcome, progress is continuing and it

is our judgement that the technology

should be available by the time it would

be needed for the final Tier 2 standards.

One serious concern with current

NOX adsorbers is that they are quickly

poisoned by sulfur in the fuel. Some

manufacturers have strongly

emphasized their belief that, in order to

meet the final Tier 2 levels, low sulfur

diesel fuel would also be required to

mitigate or prevent this poisoning

problem. In its comments on the NPRM,

Navistar indicated that the Tier 2

standards may be achievable given low

sulfur fuel and other programmatic

changes such as those included in this

Final Rule. Navistar has also been

quoted publically as describing the Tier

2 standards as ‘‘challenging but

achievable’’ given appropriate low

sulfur fuel.47 We intend to issue a

Notice of Proposed Rulemaking early in

the year 2000 intended to reduce sulfur

in highway diesel fuel as a step to

enable the technology most likely to be

used to meet the Tier 2 standards.

SCR has been demonstrated

commercially on stationary diesel

engines and can reduce NOX emissions

by 80–90%. This efficiency would be

sufficient to enable compliance with the

proposed Tier 2 standards. However,

SCR requires that the chemical urea be

injected into the exhaust before the

catalyst to assist in the destruction of

NOX. The urea must be injected at very

precise rates, which is difficult to

achieve with an on-highway engine,

because of widely varying engine

operating conditions. Otherwise,

emissions of ammonia, which have a

very objectionable odor, can occur.

Substantial amounts of urea are

required, meaning that vehicle owners

would have to replenish their vehicles’

supply of urea frequently, possibly as

often as every fill-up of fuel. As the

engine and vehicle would operate

satisfactorily without the urea (only

NOX emissions would be affected), some

mechanism would be needed to ensure

that vehicle owners maintained their

supply of urea. Otherwise, little NOX

emission reduction would be expected

in-use.

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6729

48The air quality impacts discussed above under

Section III above do not reflect these new estimates.

Regarding PM, applicable

aftertreatment devices tend to fall into

two categories: Oxidation catalysts and

traps. Diesel oxidation catalysts can

reduce total PM emissions by roughly

15–30%. They would need to be used in

conjunction with further reductions in

PM engine-out emissions in order to

meet the proposed Tier 2 standards.

Diesel particulate traps, on the other

hand, can eliminate up to 90% of diesel

PM emissions. However, some of the

means of accomplishing the

regeneration of particulate traps involve

catalytic processes that also convert

sulfur dioxide in the exhaust to sulfate.

These techniques, if used, would also

require a low sulfur fuel.

In summary, we believe that the

structure of our final program, including

the available bins and phase-in periods,

will allow the orderly development of

clean diesel engine technologies. We

believe that the interim standards are

feasible for diesel LDV/LDTs, within the

bin structure of this rule and without

further reductions in diesel fuel sulfur

levels. And, as indicated earlier, at least

one major diesel engine manufacturer

(Cummins) has publicly agreed with

this assessment. We further believe that

in the long-term, the final standards will

be within reach for diesel-fueled

vehicles in combination with

appropriate changes to diesel fuel to

facilitate aftertreatment technologies.

Manufacturers have argued that low

sulfur diesel fuel will be required to

permit diesels to meet the final Tier 2

standards, and we agree. At least one

major manufacturer (Navistar) has

indicated its belief that the final Tier 2

standards may be achievable for diesel

engines with low sulfur diesel fuel.

2. Gasoline Sulfur Control Is Needed to

Support the Proposed Vehicle Standards

As we discussed in the previous

section, we believe that the stringent

standards in this final rule are needed

to meet air quality goals and are feasible

for LDVs and LDTs. At the same time,

we believe that for these standards to be

feasible for gasoline LDVs and LDTs,

low sulfur gasoline must be made

available. The following paragraphs

explain why we think gasoline sulfur

control must accompany Tier 2 vehicle

standards.

Catalyst manufacturers generally use

low sulfur gasoline in the development

of their catalyst designs. Vehicle

manufacturers then equip their vehicles

with these catalysts and EPA certifies

them to the exhaust emission standards,

usually based on testing the

manufacturer does using low sulfur

gasoline. However, fundamental

chemical and physical characteristics of

exhaust catalytic converter technology

generally result in a significant

degradation of emission performance

when these vehicles use gasoline with

sulfur levels common in most of the

country today. This sensitivity of

catalytic converters to gasoline sulfur

varies somewhat depending on a

number of factors, some better

understood than others. Clearly,

however, as we discuss in the following

paragraphs, gasoline sulfur’s impact is

large, especially in vehicles designed to

meet very low emission standards.

This is the reason EPA has decided to

adopt a comprehensive approach to

addressing emissions from cars and

light trucks, including provisions to get

low sulfur gasoline into the field in the

same time frame needed for Tier 2

vehicles.

a. How Does Gasoline Sulfur Affect

Vehicle Emission Performance?

We know that gasoline sulfur has a

negative impact on vehicle emission

controls. Vehicles depend on the

catalytic converter to reduce emissions

of HC, CO, and NOX. Sulfur and sulfur

compounds attach or ‘‘adsorb’’ to the

precious metal catalysts that are

required to convert these emissions.

Sulfur also blocks sites on the catalyst

designed to store oxygen that are

necessary to optimize NOX emissions

conversions. While the amount of sulfur

contamination can vary depending on

the metals used in the catalyst and other

aspects of the design and operation of

the vehicle, some level of sulfur

contamination will occur in any

catalyst.

Sulfur sensitivity is impacted not only

by the catalyst formulation (the types

and amounts of precious metals used in

the catalyst) but also by factors

including the following:

• The materials used to provide

oxygen storage capacity in the catalyst,

as well as the general design of the

catalyst,

• The location of the catalyst relative

to the engine, which impacts the

temperatures inside the catalyst,

• The mix of air and fuel entering the

engine over the course of operation,

which is varied by the engine’s

computer in response to the driving

situation and affects the mix of gases

entering the catalyst from the engine,

and

• The speeds the car is driven at and

the load the vehicle is carrying, which

also impact the temperatures

experienced by the catalyst.

Since these factors vary for every

vehicle, the sulfur impact varies for

every vehicle to some degree. There is

no single factor that guarantees that a

vehicle will be very sensitive or very

insensitive to sulfur. We now believe

that there are not (and will not be in the

foreseeable future) emission control

devices available for gasoline-powered

vehicles that can meet the proposed Tier

2 emission standards that would not be

significantly impaired by gasoline with

sulfur levels common today.

b. How Large Is Gasoline Sulfur’s Effect

on Emissions?

High sulfur levels have been shown to

significantly impair the emission

control systems of cleaner, later

technology vehicles. The California LEV

standards and Federal NLEV standards,

as well as California’s new LEV–II

standards and our Tier 2 standards,

require catalysts to be extremely

efficient to adequately reduce emissions

over the full useful life of the vehicle.

In the NPRM we estimated that, based

on data from test programs conducted

by EPA and the automotive and oil

industries, LEV and ULEV vehicles

could experience, on average, a 40

percent increase in NMHC and 134

percent increase in NOX emissions

when operated on 330 ppm sulfur fuel

(our estimate in the NPRM of the

current national average sulfur level)

compared to 30 ppm sulfur fuel. New

data generated since the NPRM on

similar LEVs and ULEVs show that

when these vehicles were driven on

high sulfur (330 ppm) fuel for a few

thousand miles (as opposed to less than

100 miles for the previous data), the

NMHC and NOX emission increase due

to high sulfur fuel increased by 149

percent and 47 percent, respectively. In

other words, instead of the previous

estimated 40 percent and 134 percent

increases in NMHC and NOX emissions,

respectively, more realistic estimates

would be 100 percent and 197 percent,

respectively.48 Also, new data generated

since the NPRM for late model LEV and

ULEV vehicles that meet the federal and

California supplemental federal test

procedure (SFTP) standards and also

have very low FTP emission levels,

indicate that, on average, a 51 percent

increase in NMHC and a 242 percent

increase in NOX emissions when

operated for a short period of time on

330 ppm compared to 30 ppm could be

realized.

This level of emissions increase is

significant enough on its own to cause

a vehicle to exceed the full useful life

emission standards when operated on

sulfur levels that are substantially

higher than the levels required by

today’s rule, even with the margin of

6730 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

safety that auto manufacturers generally

include. Average sulfur levels in the

U.S. are currently high enough to

significantly impair the emissions

control systems in new technology

vehicles, and to potentially cause these

vehicles to fail emission standards

required for vehicles up through

100,000 miles (or more) of operation.

For older vehicles designed to meet

Tier 0 and Tier 1 emission standards,

the effect of sulfur contamination is

somewhat less. Still, testing shows that

gasoline sulfur increases emissions of

NMHC and NOX by almost 17% when

one of these vehicles is operated on

gasoline for less than 100 miles

containing 330 ppm sulfur compared to

operation on gasoline with 30 ppm

sulfur. Thus, Tier 0 and Tier 1 vehicles

can also have higher emissions when

they are exposed to sulfur levels

substantially higher than the proposed

sulfur standard. This increase is

generally not enough to cause a vehicle

to exceed the full useful life emission

standards in practice, but it can result

in in-use emissions increases since the

vehicle could emit at levels higher than

it would if it operated consistently on

30 ppm sulfur gasoline.

As discussed in the RIA, NLEV and

Tier 2 vehicles are significantly more

sensitive to sulfur poisoning than Tier 1

and Tier 0 vehicles. Because of this,

even in the absence of Tier 2 standards,

gasoline sulfur control to 30 ppm would

achieve about 700,000 tons of NOX

reductions per year from LDVs and

LDTs by 2020. This represents about a

third of the national NOX emission

reductions otherwise available from

these vehicles. Without these potential

emission reductions, many states would

face the potentially unmeetable

challenge of finding enough other costeffective sources of NOX emission

reductions to address their ozone

nonattainment and maintenance

problems.

Sulfur reductions will result in

reductions of other pollutants as well.

For example, the increase in CO

emissions at 330 ppm compared to 30

ppm were very similar to the results

above for NMHC. Thus, sulfur

reductions would greatly reduce CO

emissions. Another example is sulfur

reductions will help reduce emissions

of particulate matter, providing some

benefit to PM nonattainment areas

(which may or may not coincide with

ozone nonattainment areas) as well as

with visibility problems. Sulfur

reductions will also have benefits for

areas across the country with acid

deposition problems. Furthermore,

sulfur reduction, by enabling tighter

Tier 2 standards and by improving

emissions performance of the vehicles

already on the road, will lead to fewer

NMOG emissions, since, as explained in

the RIA, NMOG emissions are also

impacted by gasoline sulfur (although to

a lesser extent than NOX emissions).

Some of the NMOG emissions reduced

are air toxics. As described in Section III

above, air toxics, also known as

hazardous air pollutants, or HAPs,

contribute to a variety of human health

problems.

c. Sulfur’s Negative Impact on Tier 2

Catalysts

As we discussed in the last section,

sulfur contaminates the catalyst. In

addition, essentially all vehicles that

have been tested show that this effect is

not reversible for one or more

pollutants. The ability to reverse sulfur’s

negative effect on catalyst performance

is dependent on a number of factors.

The same factors that impact sulfur

sensitivity also impact the irreversibility

of the sulfur effect. For example, the

location of the catalyst relative to the

engine, the materials used to provide

oxygen storage capacity in the catalyst,

and the general design of the catalyst

and the mix of air and fuel (A/F)

entering the engine over the course of

operation affect irreversibility, to name

a few.

Perhaps the most significant factors

for reversibility are the mixture of air

and fuel entering the engine and catalyst

temperature. The results of numerous

studies and test programs show that rich

exhaust (absence of oxygen) mixtures in

addition to high catalyst temperatures

(in excess of 700°C) can remove sulfur

from the catalyst. Rich exhaust mixtures

can occur intentionally and

unintentionally, depending on the level

of sophistication of the fuel control

system. An intentional rich exhaust

mixture is known as fuel ‘‘enrichment.’’

There are different types of enrichment.

For example, there is ‘‘commanded’’

enrichment, which is used to provide

extra power when the engine is under

a load (e.g., accelerations), as well as a

means to cool the catalyst. Also, there

is enrichment which results from the

normal fluctuations in A/F that occur

during typical ‘‘closed-loop’’ FTP

operating conditions. The amount of

enrichment necessary for sulfur removal

is a function of several factors: the

‘‘magnitude’’ of the enrichment event,

the duration of the enrichment event,

and the frequency of which the

enrichment event occurs.

While the amount of fuel enrichment

is critical in the removal of sulfur from

the catalyst, high catalyst temperature is

equally as important. In order to meet

strict Tier 2 standards, manufacturers

are going to have to balance tight A/F

control with improved catalyst

performance, with an eye towards better

catalyst thermal management. Many

manufacturers are going to have to

depend more on the precious metal

palladium for oxidation of NMOG and

CO emissions, as well as the reduction

of NOX, because palladium is more

tolerant to high temperatures. Since the

vast majority of emissions still occur

immediately following a cold start when

the catalyst is still cool, further

reductions to cold start emissions can be

achieved by locating the catalysts very

close to the engine. The closer

proximity to the engine helps to activate

the catalyst sooner by taking advantage

of the additional heat supplied to the

catalyst by the exhaust manifolds.

Palladium is very sensitive to sulfur

and, consequentially, catalyst systems

that rely heavily on this metal tend to

be more sensitive to sulfur and less

reversible. The precious metal platinum,

although usually a little more effective

at oxidizing NMOG and CO and slightly

less sensitive to sulfur than palladium,

is too sensitive to high temperature to

survive the close proximity to the

engine and is not anticipated to be used

for close-coupled applications.

As discussed above, manufacturers

will need to make modifications to their

emission system calibrations by

optimizing fuel control, spark timing,

EGR and other parameters in

conjunction with improvements to

catalyst systems, in order to meet Tier

2 emission standards. This combination

of emission control strategies can result

in significant trade-offs between NMOG

and NOX control. There can be

considerable uncertainty associated

with balancing these trade-offs at very

low emissions levels if the vehicle is

periodically operated on high sulfur

fuels.

Our federal supplemental federal test

procedure (SFTP) standards, as well as

California’s SFTP standards, both of

which take effect in the 2001 model

year, can further exacerbate this

problem. The SFTP standards are

intended to better address and control

emissions under driving conditions not

captured when compliance with our

FTP-based exhaust emissions standards

is demonstrated, such as operation with

the air conditioning turned on or

driving at very high rates of acceleration

and vehicle speeds (hereafter referred to

simply as aggressive driving). This is an

important factor in assessing sulfur

irreversibility, because Tier 2 vehicles

will have to meet more stringent

exhaust emission standards and will

have to meet these standards over the

wider variety of operating conditions

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6731

49The FTP (Federal Test Procedure) is the basic

driving cycle used for federal emissions testing; the

LA4 cycle is a component of the FTP. The REP05

cycle developed by EPA is representative of all

driving that occurs outside the LA4 or FTP cycle.

All but one of the aggressive accelerations found in

the US06 cycle were taken from the REP05. While

each segment of the US06 cycle was taken from

actual in-use driving, the timing and combination

of these segments is not representative of in-use

driving in the way REP05 is representative.

included in the SFTP provisions. Hence,

they will have to be designed to meet

the emission standards under all such

operating conditions; these design

changes may influence how irreversible

the sulfur effect will be, as explained

below.

Since wide variations in the A/F ratio

help to remove sulfur from the catalytic

surface, there is concern that vehicles

which meet the SFTP standards, when

driven aggressively, will experience

insufficient enrichment to purge sulfur

from the catalyst. Currently, when

driven aggressively, the A/F ratio for

most vehicles (those not certified to

SFTP standards) is quite variable.

Meeting the SFTP standards will ensure

that manufacturers carefully control the

A/F ratio over essentially all in-use

driving conditions. This absence of

widely varying A/F could therefore

inhibit the removal of sulfur from the

catalyst once operation on high sulfur

fuel ceased.

In order to quantify how irreversible

the sulfur effect would be when

catalysts exposed to high sulfur fuel are

then exposed to lower sulfur fuel,

several test programs were developed by

EPA and industry. The vehicles in these

test programs consisted of LDVs and

LDTs that met either EPA Tier 1 or

California LEV and ULEV emission

standards. All of the vehicles were first

tested at a low sulfur level (e.g., 30 or

40 ppm) to establish a baseline. The

vehicles were then re-tested with high

sulfur fuel (e.g., 350 to 540 ppm). After

emission results had stabilized, the

vehicles were again re-tested with low

sulfur fuel. Prior to each of the second

series of low sulfur tests, the vehicles

were operated over a short driving cycle

to help purge (i.e., remove) sulfur from

the catalyst. Two different cycles were

used to purge sulfur, representing

different types of driving: moderate

urban conditions and aggressive

conditions. The FTP cycle, which

represents moderate urban driving, and

the REP05 49 cycle, which represents

very aggressive driving (e.g., hard

accelerations, high speed cruises), were

the two cycles used.

The vehicles tested exhibited a wide

range of irreversibility, for reasons that

are not fully understood. The data

published in the NPRM, showed that

the effect of operation on high sulfur

fuel was irreversible on one or more

pollutants after operation on low sulfur

fuel. NOX emissions were 15 percent

irreversible. None of the vehicles were

designed or modified to meet either the

California or federal SFTP emissions

standards. The only data used in an

attempt to quantify the effect of

aggressive operation on sulfur

reversibility was from a catalyst

manufacturer that performed some

vehicle testing with catalysts which

were bench aged with low and high

sulfur fuel that appeared to closely

approximate the impact aggressive

operation would have on sulfur

irreversibility. It was this data on which

we based our projection of sulfur

irreversibility for Tier 2 vehicles at 50

percent for NMHC and NOX emissions.

Subsequent comments on the validity of

these estimates after the publishing of

the NPRM prompted several additional

test programs on sulfur irreversibility.

The sulfur irreversibility test

programs that followed the NPRM

focused on vehicles that had emission

levels that met or were close to Tier 2

emission standards and also met the

US06 or aggressive driving portion of

the SFTP emission standards. Although

numerous vehicles were tested, only

four met both of the above criteria. (We

had tried to supplement the data base,

but we were only able to add a limited

number of vehicles.) We also decided to

quantify irreversibility for NMHC and

NOX emissions together instead of

independently, because per our

discussion above, sensitivity and

irreversibility of either pollutant

appears to be very dependent on the

particular strategy chosen to reduce

these emissions (particularly engine

calibration and catalyst loading of

precious metals and oxygen storage).

The new data exhibited a range of

variability among vehicles and

pollutants, similar to the data presented

in the NPRM. The most important

distinction between the new FRM data

and the old NPRM data was that the

new data showed that, on average,

NMHC+NOX emissions in three out of

four vehicles were not fully reversible

after aggressive driving. Based on this

data, we project that NMHC+NOX

emissions will be 20 to 65 percent

irreversible for Tier 2 vehicles under

typical in-use driving, including

aggressive driving.

As discussed above, the combination

of calibration changes and emission

system hardware modifications needed

to meet our stringent Tier 2 emissions

standards, can result in significant

trade-offs between NMHC/NMOG and

NOX control. There can be considerable

uncertainty associated with balancing

these trade-offs at very low emissions

levels if the vehicle is periodically

operated on high sulfur fuels, making

the ability to remove sulfur from the

catalyst highly uncertain. For example,

a given catalyst today may be fully

reversible for one pollutant and only

partially reversible for another.

However, because of the trade-off in

NMOG and NOX performance, the

modifications necessary to get that

vehicle to meet both emission standards

may result in the opposite effect for

reversibility; i.e., full reversibility for

NMOG and partial reversibility for NOX.

There is no technical certainty that both

the NMOG and NOX emission standards

can be met without compromising

reversibility performance. Therefore, we

continue to believe that sulfur’s negative

impact on Tier 2 catalysts is a

substantial concern.

The preceding discussion focused on

the irreversibility of the sulfur impact

on emissions from current gasoline

engine technologies. There are new

technologies under development, which

could be sold in the U.S. in the middle

of the next decade (the same time that

Tier 2 vehicles are being introduced),

which also appear to be very sensitive

to sulfur and largely unable to reverse

this sulfur impact. One of these

technologies is the direct injection

gasoline (GDI) engine. These engines

utilize much more air than is needed to

burn the fuel, unlike conventional

gasoline engines that operate under

conditions where only just enough air to

completely burn the fuel is introduced

into the engine. This GDI technology

allows these engines to be up to 25%

more fuel efficient than current gasoline

engines and to emit up to 20% less

carbon dioxide. GDI engines are

currently being introduced in both

Japan and Europe (which have or will

soon require low sulfur gasolines).

Because of the significant operating

differences with GDI engines, these

vehicles will likely require emission

control technology substantially

different from that used on conventional

gasoline engines. For example, a GDI

engine may require a NOX adsorber to

meet the proposed Tier 2 NOX standard.

High fuel sulfur levels quickly and

permanently degrade the performance of

these NOX adsorbers. Thus, to enable

the sale of advanced, high efficiency

GDI engines in the U.S. under the Tier

2 standards, it appears that low sulfur

gasoline would have to be available

nationwide by the time this technology

becomes available.

The fuel cell is another promising

propulsion system that is being

developed for possible introduction to

6732 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

50U.S. EPA, ‘‘OBD & Sulfur Status Report:

Sulfur’s Effect on the OBD Catalyst Monitor on Low

Emission Vehicles,’’ March 1997, updated

September 1997.

51 In this section and also in section V, we make

various references to the Tier 2 program, the interim

program (or standards) and the final Tier 2

standards. The Tier 2 program includes the interim

program (or standards) and the final Tier 2

standards. Some discussion is applicable to the

entire Tier 2 program, some to the interim program

(or standards) only and some is only applicable to

the final Tier 2 standards. As the program is

complex, we advise you to read carefully to discern

the applicability of the text to the proper model

years and categories of vehicles.

consumers early in the next century.

Fuel cells are being designed to operate

on a variety of fuels, including gasoline

and diesel fuel. The basic fuel cell

technology is highly sensitive to sulfur.

Almost any level of sulfur in the fuel

will disable the fuel cell. One possible

solution is to install a technology that

essentially filters out the sulfur before it

enters the fuel cell. However, such

sulfur ‘‘guards’’ are costly and could not

practically be used like a disposable

filter (requiring the vehicle owner to

change the sulfur guard frequently,

much like changing an oil filter) in

situations where constant exposure to

high sulfur levels occurs. (Even

exposure to relatively low sulfur levels

will likely require periodic replacement

of the sulfur guard to ensure adequate

protection for the fuel cell.) Therefore,

the amount of sulfur in the fuel must be

limited to that which can be removed by

one or at most two sulfur guards over

the life of the vehicle. Thus, in order for

fuel cells operating on gasoline to be

feasible in the U.S., low sulfur fuels

would have to be available nationwide

by the time this technology becomes

available.

d. Sulfur Has Negative Impacts on OBD

Systems

As discussed in more detail in the

RIA, EPA believes that sulfur in gasoline

can adversely impact the onboard

diagnostic (OBD) systems of current

vehicles as well as vehicles meeting the

Tier 2 standards. This is an important

factor supporting the need for a national

sulfur control program. EPA’s onboard

diagnostics (OBD) regulations require

that all vehicles be equipped with a

system that monitors, among other

things, the performance of the catalyst

and warns the owner if the catalyst is

not functioning properly. The OBD

catalyst monitor is designed to identify

those catalysts with pollutant

conversion efficiencies that have been

reduced to the extent that tailpipe

emissions would exceed a specified

multiple of the applicable hydrocarbon

emissions standard. For California LEV

and federal NLEV vehicles, that

multiple is 1.75 times the applicable

hydrocarbon emissions standard; for

federal Tier 1 vehicles, that multiple is

1.5 times the applicable hydrocarbon

standard added to the 4,000 mile

emission level.

We want to ensure that OBD systems

operate correctly, and thus the

possibility that gasoline sulfur may

interfere with these systems was another

consideration when evaluating the need

for a national sulfur program. Our

evaluation of sulfur’s effect on OBD

systems was summarized in a staff

paper in 1997.50 We concluded that

sulfur can affect the decisions made by

the OBD systems. Sulfur appears to

affect the oxygen sensor downstream of

the catalyst, which is used in the OBD

systems, and it is not clear that the

conditions that seem to reverse sulfur’s

effect on the catalyst will also reverse

any sulfur impact on the downstream

oxygen sensors. Indirectly, sulfur

impacts OBD systems because it can

impair a catalyst that would otherwise

be operating satisfactorily, thereby

triggering the OBD warning lights.

While this would indicate a properly

operating OBD system, auto

manufacturers have expressed the

concern that consumers using high

sulfur fuel may experience OBD

warnings much more frequently than

they would if operating on low sulfur

gasoline, and that this could lead to a

loss of consumer confidence in or

support for OBD systems. Consumers

may then ignore the OBD warning

system and drive a potentially high

emitting vehicle (which may have

nothing to do with exposure to sulfur),

contributing even more to air quality

problems. Another possible scenario is

that the OBD system may be impaired

by sulfur in such a way that it does not

register an improperly functioning

catalyst, even if the catalyst is impaired

for reasons unrelated to exposure to

sulfur. This would defeat the purpose of

OBD systems.

The reduction of sulfur levels for

gasoline should resolve any concerns

over the ability of the OBD system to

make proper decisions. The use of low

sulfur fuel should ensure that the OBD

warning light goes on when it is

supposed to and is not influenced by

sulfur contamination of the catalyst

and/or OBD system.

B. Our Program for Vehicles

The program we are establishing

today for cars, light trucks, and large

passenger vehicles will achieve the

same large NOX reductions that we

projected for the proposed program. The

program is very similar to our proposed

program in all major respects. We have

been able to retain the general structure,

stringency, and emissions benefits of the

proposal in this final rule. Where we

have made adjustments to the proposed

program, we have done so in ways that

improve the implementation of the

program without changing the overall

environmental benefits that the program

will achieve. And by creating a new

category of vehicles subject to the Tier

2 standards, medium-duty passenger

vehicles, the final rule will ensure that

all passenger vehicles expected to be on

the road in the foreseeable future will be

very clean.

We have seriously considered the

input of all stakeholders in developing

our final rule and believe the program

finalized below balances the concerns of

all stakeholders while achieving the

needed air quality benefits. In general,

the adjustments we have made are

aimed at improving the implementation

efficiency of the program by better

aligning the federal Tier 2 program with

the NLEV program and with California’s

program especially during the interim

program. 51 Extensive comments from

manufacturers led us to conclude that

better harmony between the two

programs would reduce the engineering,

testing and certification workload

related to our interim program. Where

we could make changes to increase the

overlap of the two programs while

maintaining the NOX reductions of the

proposal, we have done so. These

changes are discussed in detail in this

section IV.B. and in sections V.A. and

V.B.

Our final rule also includes

provisions to regulate complete heavyduty passenger vehicles (primarily

SUVs and passenger vans) of less than

10,000 pounds GVWR within the Tier 2

program. Standards for these vehicles

were not included in the Tier 2 NPRM,

but were proposed in a subsequent

NPRM on October 29, 1999 (64 FR

58472). The final provisions for these

vehicles are addressed in section

IV.B.4.g. These heavier vehicles have

been recategorized as medium duty

passenger vehicles (MDPVs). They are

included in the Tier 2 program starting

with model year 2004 and will be

treated similarly to HLDTs, unless

otherwise noted.

The next sections of the preamble

describe our final program in detail and

include changes and adjustments from

the NPRM that we believe address many

concerns raised by the Alliance and

others. While these changes ease the

burden on manufacturers, they have

little or no impact on the air quality

benefits of the Tier 2 program.

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6733

52The NLEV program is a voluntary program,

adopted by all major LDV and LDT manufacturers.

It applies only to LDVs, LDT1s and LDT2s. It does

not apply to HLDTs.

53Throughout this text, the term ‘‘full life’’ is

used in reference to vehicle standards to mean ‘‘full

useful life’’ which is currently 10 years/100,000

miles for LDVs and LLDTs, but 11 years/120,000

miles for HLDTs. Similarly, ‘‘intermediate life’’

refers to intermediate useful life standards which

apply for the period of 5 years/50,000 miles. In this

rulemaking we are retaining the current full useful

life period for interim LDVs and LLDTs, but raising

it for Tier 2 vehicles to 10 years/120,000 miles.

In a number of places in the following

text, we mention that changes are being

made ‘‘in response to comments’’. For a

full summary of the comments and for

our responses to those comments, we

refer you to the Response to Comments

document contained in the docket for

this rulemaking or available from the

Office of Mobile Sources web site (see

web address at the beginning of this

document).

1. Overview of the Vehicle Program

The vehicle-related part of today’s

final rule covers a wide range of

standards, concepts, and provisions that

affect how vehicle manufacturers will

develop, certify, produce, and market

Tier 2 vehicles. This Overview

subsection provides readers with a

broad summary of the major vehiclerelated aspects of the rule. Readers for

whom this Overview is sufficient may

want to move on to the discussion of the

key gasoline sulfur control provisions

(Section IV.C.). Readers wishing a more

detailed understanding of the vehicle

provisions can continue beyond the

Overview to deeper discussions of key

issues and provisions (Sections IV.B.–2,

3, and 4) as well as discussions of

additional provisions (Section V.A.).

Readers should refer to the regulatory

language found at the end of this

preamble for a complete compilation of

the requirements.

To understand how the program will

work, it is useful to review EPA’s

classification system for light-duty

vehicles and trucks. The light-duty

category of motor vehicles includes all

vehicles and trucks at or below 8500

pounds gross vehicle weight rating, or

GVWR (i.e., vehicle weight plus rated

cargo capacity). Table IV.B.–1 shows the

various light-duty categories and also

shows our new medium-duty passenger

vehicle (MDPV) category, discussed in

section IV.B.4.g.. In the discussion

below, we make frequent reference to

two separate groups of light vehicles: (1)

LDV/LLDTs, which include all LDVs

and all LDT1s and LDT2s; and (2)

HLDTs, which include LDT3s and

LDT4s. We also make mention of

MDPVs although the details of our

program for those vehicles are deferred

to IV.B.4.g. at the end of section IV.B.

TABLE IV.B.—1 LIGHT-DUTY VEHICLES

AND TRUCKS AND MEDIUM-DUTY

PASSENGER VEHICLES; CATEGORY

CHARACTERISTICS

Characteristics

LDV .................... A passenger car or passenger car derivative

seating 12 passengers

or less.

Light LDT (LLDT) Any LDT rated at up

through 6,000 lbs

GVWR. Includes LDT1

and LDT2.

Heavy LDT

(HLDT).

Any LDT rated at greater

than 6,000 lbs GVWR.

Includes LDT3 and

LDT4s.

MDPV ................. A heavy-duty passenger

vehicle rated at less

than 10,000 lbs GVWR.

(The inclusion of

MDPVs is discussed

primarily in Section

IV.B.4.g.)

a. Introduction

Today’s final rule incorporates

concepts from the federal NLEV

program which began phase-in in the

1999 model year for LDV/LLDTs.52 The

program in today’s rule takes the

corporate averaging concept and other

provisions from NLEV but changes the

focus from NMOG to NOX and applies

them to all LDVs and LDTs. The final

rule is compatible with the California

LEV II (CalLEV II) program scheduled to

take effect in 2004. The emission

standard ‘‘bins’’ used for this average

calculation are different in several

respects from those of the CalLEV II

program, yet still allow harmonization

of federal and California vehicle

technology.

The Tier 2 corporate average NOX

level to be met through these

requirements ultimately applies to all of

a manufacturer’s LDVs and LDTs

(subject to two different phase-in

schedules) regardless of the fuel used.

Meanwhile, until the final Tier 2

standards are completely phased in,

separate interim standards apply to

LDV/LLDTs and HLDTs.

As proposed in the NPRM and

finalized in today’s document, the Tier

2 program will take effect in 2004, with

full phase in occurring by 2007 for LDV/

LLDTs and 2009 for HLDTs. During the

phase-in years of 2004–2008, vehicles

not certified to Tier 2 requirements will

meet interim requirements also using a

bins system, but with less stringent

corporate average NOX standards.

In the discussions below, we set forth

different Tier 2 phase-in schedules for

the two different groups of vehicles

(LDV/LLDTs and HLDTs) as well as two

different interim fleet average NOX

standards for 2004 and later model year

vehicles awaiting phase-in to the Tier 2

standards.

In the NPRM, we set forth separate

tables of full life standard bins for the

interim programs and the final Tier 2

program, but we proposed that

manufacturers could use all bins for

interim or Tier 2 vehicles during the

phase-in years.53 We also proposed

similar sets of tables for intermediate

life standards. In this final rule, for

simplicity and to accommodate

additional bins, including some

suggested by the Alliance, we have

combined all of the full life bins into

one table and all of the intermediate life

bins into one table. The bins system and

the choice of the individual bins is

discussed in detail below.

References to California LEV II Program

Throughout this preamble, we make

reference to California’s LEV II program

and its requirements. The LEV II

program was approved by the California

ARB at a hearing of November 5, 1998.

Numerous draft documents were

prepared by ARB staff in advance of that

hearing and made available to the

public. Those documents were

referenced in our NPRM and included

in the docket. Some of those documents

were modified as a result of changes to

the proposed program made at the

hearing and due to comments received

after the hearing. ARB prepared final

documents without significant change.

The final program was approved by

California’s Office of Administrative

Law on October 28, 1999 and filed with

the Secretary of State to become

effective on November 27, 1999.

We have placed copies of the latest

available documents, some of which we

used in the preparation of this final rule,

in the docket. You may also obtain these

documents and other information about

California’s LEV II program from ARB’s

web site: (www.arb.ca.gov/regact/levii/

levii.htm).

In the regulatory text that follows this

preamble, we incorporate by reference a

number of documents related to LEVII

and California test procedures under

6734 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

54These bins are unlikely to be used in the

Federal program because they contain the same

NOX standard as the Federal bins, but contain more

stringent NMOG standards than the Federal bins.

These bins, which provide extra opportunity for a

manufacturer to gain NMOG credits in California

are not needed or useful in the Federal program

where there is no NMOG corporate average

standard. The two deleted bins are bin 4 from the

proposed Tier 2 bins and bin 3 from the proposed

interim bins for LDV/LLDTs. Dropping these bins

does not affect harmonization with California

standards because the federal program includes

bins having the same NOX standard with higher

NMOG standards.

LEVII. These documents are available in

the docket for today’s rulemaking.

b. Corporate Average NOX Standard

The program we are finalizing today

will ultimately require each

manufacturer’s average full life NOX

emissions over all of its Tier 2 vehicles

to meet a NOX standard of 0.07 g/mi

each model year. Manufacturers will

have the flexibility to certify Tier 2

vehicles to different sets of exhaust

standards that we refer to as ‘‘bins,’’ but

will have to choose the bins so that their

corporate sales weighted average full

life NOX level for their Tier 2 vehicles

is no more than the 0.07 g/mi. (We

discuss the bins in the next subsection.)

A corporate average standard enables

the program’s air quality goals to be met

while allowing manufacturers the

flexibility to certify some models above

and some models below the standard.

Manufacturers can apply technology to

different vehicles in a more costeffective manner than under a single set

of standards that all vehicles have to

meet.

Each manufacturer will determine its

year-end corporate average NOX level by

computing a sales-weighted average of

the full life NOX standards from the

various bins to which it certified any

Tier 2 vehicles. The manufacturer will

be in compliance with the standard if its

corporate average NOX emissions for its

Tier 2 vehicles meets or falls below 0.07

g/mi. In years when a manufacturer’s

corporate average is below 0.07 g/mi, it

can generate credits. It can trade (sell)

those credits to other manufacturers or

use them in years when its average

exceeds the standard (i.e. when the

manufacturer runs a deficit). The

averaging program is described in detail

in later text.

c. Tier 2 Exhaust Emission Standard

‘‘Bins’’

We are finalizing a Tier 2 bin

structure having eight emission

standards bins (bins 1–8), each one a set

of standards to which manufacturers

can certify their vehicles. Table IV.B.–2a

shows the full useful life standards that

will apply for each bin in our final Tier

2 program, i.e. after full phase-in occurs

for all LDVs and LDTs. Two additional

bins, bins 9 and 10, will be available

only during the interim program and

will be deleted before final phase-in of

the Tier 2 program. Table IV.B.–2b

shows all the bins from Table IV.B.–2a

and also shows extra bins and higher

available standards for certain

pollutants that are available prior to full

Tier 2 phase-in. An eleventh bin, only

for MDPVs is discussed in section

IV.B.4.g.

Many bins have the same values as

bins in the California LEV II program as

a means to increase the economic

efficiency of the transition to as well as

model availability. Further, we added

bins that are not a part of the California

program to modestly increase the

flexibility of the program for

manufacturers without compromising

air quality goals. As discussed in

Section IV.B.4. below, we believe these

extra bins will help provide incentives

for manufacturers to produce vehicles

with emissions below 0.07 g/mi NOX.

The two highest of the ten bins shown

in Table IV.B.2b. are designed to

provide flexibility only during the

phase-in years and will terminate after

the standards are fully phased in,

leaving eight bins in place for the

duration of the Tier 2 program.

The NPRM full life standards

contained seven Tier 2 bins as well as

two separate tables of bins for interim

vehicles. We proposed that

manufacturers would be able to use all

the bins during the phase in years

regardless of whether they were

certifying Tier 2 vehicles or interim

vehicles.

The program we are finalizing today:

• Combines the bins from the NPRM;

• Omits two bins that were included

in the NPRM for harmony with

California but which are unlikely to be

used; 54;

• Adds 2 bins to increase compliance

flexibility without reducing

environmental benefits;

• Adds a temporary bin only for

MDPVs that expires after 2008. This bin

is in addition to the 10 bins shown in

tables of bins in this preamble;

• Establishes a PM value for the

highest bin available during the interim

program (bin 10) that is more stringent

than the corresponding standard in the

NLEV program;

• Provides temporary higher NMOG

standards that expire after 2006 for

certain interim LDT2s and LDT4s

produced by qualifying manufacturers.

Tables IV.B.–2a and 2b show the bins

for full life standards. Table IV.B.–2b is

repeated later in the text where

intermediate life standards are also

shown. These tables omit the temporary

bin for MDPVs. This bin is usable only

by MDPVs and is addressed separately

in section IV.B.4.g.

TABLE IV.B.–2A.—FINAL TIER 2 LIGHT-DUTY FULL USEFUL LIFE EXHAUST EMISSION STANDARDS

[Grams per mile]

Bin No. NOX NMOG CO HCHO PM

8 ............................................................................................................... 0.20 0.125 4.2 0.018 0.02

7 ............................................................................................................... 0.15 0.090 4.2 0.018 0.02

6 ............................................................................................................... 0.10 0.090 4.2 0.018 0.01

5 ............................................................................................................... 0.07 0.090 4.2 0.018 0.01

4 ............................................................................................................... 0.04 0.070 2.1 0.011 0.01

3 ............................................................................................................... 0.03 0.055 2.1 0.011 0.01

2 ............................................................................................................... 0.02 0.010 2.1 0.004 0.01

1 ............................................................................................................... 0.00 0.000 0.0 0.000 0.00

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6735

55 In the NPRM, we proposed that hydrocarbon

standards would be measured in terms of ‘‘nonmethane organic gases’’ (NMOG) regardless of fuel.

For reasons explained elsewhere in this preamble

we will permit non-methane hydrocarbons (NMHC)

as an option in the final rule for all fuels except

alcohol fuels and compressed natural gas . NMHC

and NMOG are very similar for gasoline and diesel

fuel emissions.

TABLE IV.B.–2B.—TIER 2 LIGHT-DUTY FULL USEFUL LIFE EXHAUST EMISSION STANDARDS—INCLUDING BINS APPLICABLE

DURING INTERIM PROGRAM ONLY

[Grams per mile]

Bin No. NOX NMOG CO HCHO PM Comments

10 ................................................ 0.6 0.156/0.230 4.2/6.4 ......... 0.018/0.027 0.08 abcd

9 .................................................. 0.3 0.090/0.180 4.2 ............... 0.018 ........... 0.06 abc

8 .................................................. 0.20 0.125/0.156 4.2 ............... 0.018 ........... 0.02 b f

Notes:

aBin deleted at end of 2006 model year (2008 for HLDTs).

bThe higher of the two temporary NMOG, CO and HCHO values apply only to HLDTs.

cAn additional higher temporary bin restricted to MDPVs is discussed in section IV.B.4.g.

dOptional temporary NMOG standard of 0.280 g/mi applies for qualifying LDT4s and MDPVs only, see text.

eOptional temporary NMOG standard of 0.130 g/mi applies for qualifying LDT2s only, see text.

f

Higher temporary NMOG value of 0.156g/mi deleted at end of 2008 model year.

The corporate average concept using

bins will provide a program that gets

essentially the same emission

reductions we would expect from a

straight 0.07 g/mi standard for all

vehicles because all NOX emissions

from Tier 2 vehicles in bins above 0.07

g/mi will need to be offset by NOX

emissions from Tier 2 vehicles in bins

below 0.07 g/mile. This focus on NOX

allows NMOG 55 emissions to ‘‘float’’ in

that the fleet NMOG emission rate

depends on the mix of bins used to meet

the NOX standard. However, as you can

see by examining the bins, any

combination of vehicles meeting the

0.07 g/mi average NOX standard will

have average NMOG levels below 0.09

g/mi. The actual value will vary by

manufacturer depending on the sales

mix of the vehicles used to meet the

0.07 g/mi average NOX standard. In

addition, there will be overall

improvements in NMOG since Tier 2

incorporates HLDTs, which are not

covered by the NLEV program. Tier 2

also imposes tighter standards on LDT2s

than the NLEV program by making them

average with the LDVs and LDT1s.

NLEV has separate, higher standards for

LDT2s. We did not adopt any bins for

LDVs and LDTs with standards higher

than we proposed.

d. Schedules for Implementation

We recognize that the Tier 2 standards

pose greater technological challenges for

larger light duty trucks ( HLDTs) than

for LDVs and smaller trucks (LDT1s and

LDT2s). We believe that additional

leadtime is appropriate for HLDTs.

HLDTs have historically been subject to

less stringent vehicle-based standards

than lighter trucks and LDVs. Also,

HLDTs were not subject to the voluntary

emission reductions implemented for

LDVs, LDT1s and LDT2s in the NLEV

program. Consequently we are finalizing

as proposed, separate phase-in programs

for HLDTs and LDV/LLDTs . Our phasein approach will provide HLDTs with

extra time before they need to begin

phase-in to the final Tier 2 standards

and will also provide two additional

years for them to fully comply. Table

IV.B–3 provides a graphical

representation of how the phase-in of

the Tier 2 program will work for all

vehicles. This table shows several

aspects of the program:

• Phase-in of the Tier 2 standards;

• Phase-in/phase-out requirements of

the interim programs;

• Phase-in requirements of new

evaporative standards;

• Years that can be included in

alternative phase-in schedules;

• Years in which manufacturers can

bank NOX credits through ‘‘early

banking’’ and

• ‘‘Boundaries’’ on averaging sets in

the Tier 2 and interim programs.

• Averaging provisions for MDPVs

(see section IV.B.4.g. for discussion)

We discuss each of these topics in

detail below and make numerous

references to Table IV.B–3.

BILLING CODE 6560–50–P

6736 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

BILLING CODE 6560–50–C

As described in detail in the Response

to Comments document, the Alliance

proposal would have delayed final

implementation of Tier 2 standards

until 2011. We are not adopting the

Alliance’s time schedule, because we

believe the shorter schedule we

proposed is feasible and that there is no

reason to delay the final benefits of the

Tier 2 standards. In fact, numerous

commenters representing state,

environmental and health groups argued

that our original proposal gave

manufacturers too much time to bring

the HLDTs into line with LDVs and

LLDTs. We believe the two extra years

proposed in the NPRM remain

appropriate. HLDTs will face greater

challenges than LDVs/LLDTs because

their emission control systems will need

to be durable under potentially heavier

loads and tougher operating conditions

than LDV/LLDTs. Their sales are small

relative to the rest of the light duty fleet

(they will comprise about 14% of the

light duty fleet in 2004), and they will

benefit from industry experience with

the lighter vehicles. In addition, HLDTs

will not remain at high Tier 1 levels

until they phase-in to Tier 2. Rather,

they will have to meet interim standards

that impose a NOX cap of 0.60 g/mi and

phase-in a corporate average NOX

standard of 0.20 g/mi. These standards

represent a significant reduction from

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6737

56Under Tier 1 standards, LDT3s are subject to

a 0.98 g/mi NOX standard while LDT4s are subject

to an even higher NOX standard of 1.53 g/mi.

57The NLEV program imposes NMOG average

standards that translate into full useful life NOX

levels of about 0.3 g/mi for LDV/LDT1s and 0.5 g/

mi for LDT2s.

58The NLEV program does not impose average

NOX standards, but the NMOG average standards

that it does impose will lead to full useful life NOX

levels of about 0.3 g/mi for LDV/LDT1s.

applicable Tier 1 standards.56 Interim

standards are discussed in detail later in

this preamble.

i. Implementation Schedule for Tier 2

LDVs and LLDTs

We are finalizing the implementation

schedule for the Tier 2 standards as

proposed in the NPRM. Thus, the

standards will take effect beginning

with the 2004 model year for light duty

vehicles and trucks at or below 6000

pounds GVWR (LDV/LLDTs).

Manufacturers will phase their vehicles

into the Tier 2 standards beginning with

25 percent of LDV/LLDT sales that year,

50 percent in 2005, 75 percent in 2006,

and 100 percent in 2007. Manufacturers

will be free to choose which vehicles are

phased-in each year. However, in each

year during (and after) the phase-in, the

manufacturer’s average NOX for its Tier

2 vehicles must meet the 0.07 g/mi

corporate average standard. This phasein schedule, which is consistent with

that of the California LEV II program,

provides between four and seven years

of leadtime for the manufacturers to

bring all of their LDV/LLDT production

into compliance. These vehicles

constitute about 86 percent of the light

duty fleet.

To increase manufacturer flexibility

and provide incentives for early

introduction of Tier 2 vehicles, we are

also finalizing provisions from the

NPRM that permit manufacturers to use

alternative phase-in schedules that will

still require 100 percent phase-in by

2007, but recognize the benefits of early

introduction of Tier 2 vehicles, and

allow manufacturers to adjust their

phase-in to better fit their own

production plans. (See section

IV.B.4.b.ii. below.)

ii. Implementation Schedule for Tier 2

HLDTs

The Tier 2 phase-in schedule for

HLDTs is also being finalized as

proposed. The phase-in for final Tier 2

standards for HLDTs will start later and

end later than that for LDVs and LLDTs.

Fifty percent of each manufacturer’s

HLDTs must meet Tier 2 standards in

2008, and 100 percent must meet Tier

2 standards in 2009. As with the LDV/

LLDTs, the Tier 2 HLDTs must meet a

corporate average NOX standard of 0.07

g/mi. This delayed phase-in schedule:

• Provides significant interim

emission reductions starting in 2004

(discussed separately below);

• Recognizes the relatively high

emission standards that currently apply

to HLDTs;

• Provides manufacturers with

adequate lead time before they must

bring HLDTs into compliance with final

Tier 2 standards;

• Provides manufacturers the

opportunity to apply and evaluate Tier

2 technology on LDV/LLDTs before

having to apply it to HLDTs; and

• Provides manufacturers the

opportunity to apply and evaluate Tier

2 technology on HLDTs on a relatively

small scale to meet California LEV II

requirements before having to apply it

to HLDTs nationwide.

As with the LDV/LLDTs above, to

encourage early introduction of Tier 2

HLDTs and to provide manufacturers

with greater flexibility, we are finalizing

provisions to permit manufacturers to

generate early Tier 2 NOX credits and to

use alternative phase-in schedules that

still result in 100% phase-in by 2009.

(See sections IV.B.4.d.iv. and IV.B.4.b.ii,

respectively, below.)

e. Interim Standards

The interim standards discussed

below are a major source of emission

reductions in the early years of the

vehicle control program. The NOX

emission standards for LDT2s and

LDT4s, which comprise about 40

percent of the fleet, are more stringent

than the corresponding standards in the

NLEV and CAL LEV I programs. These

standards also are important because

they set the stage for a smooth transition

to the final Tier 2 standards.

The two groups of vehicles (LDV/

LLDTs and HLDTs) will be approaching

the Tier 2 standards from quite different

emission ‘‘backgrounds’’. LDV/LLDTs

will be at NLEV levels, which require

NOX emissions of either 0.3 or 0.5g/mi

on average, 57 while HLDTs will be at

Tier 1 levels facing NOX standards of

either 0.98 or 1.53 g/mi, depending on

truck size. These Tier 1 NOX levels for

HLDTs are very high (by a factor of 14–

22) relative to our 0.07 g/mi Tier 2 NOX

average. To address the disparity in

emission ‘‘backgrounds’’, while gaining

air quality benefits from vehicles during

the phase-in period, we proposed and

are finalizing separate interim average

NOX standards for the two vehicle

groups during the phase-in period. The

provisions described below will apply

in 2004 for all LDVs and LDTs not

certified to Tier 2 standards. The

relationship of the interim programs to

the final Tier 2 standards is shown in

Table IV.B–3.

Interim vehicles will certify to the

same bins as Tier 2 vehicles. As

described earlier in this preamble, we

have merged the tables of bins from the

NPRM for simplicity and added a few

bins. Bins 9 and 10 were drawn from the

tables of interim bins in the NPRM, and

are intended only for use during the

phase-in years. Therefore, these two

bins will be discontinued after 2006

(2008 for HLDTs).

i. Interim Exhaust Emission Standards

for LDV/LLDTs

Beginning with the 2004 model year,

all new LDVs, LDT1s and LDT2s not

incorporated under the Tier 2 phase-in

will be subject to an interim corporate

average NOX standard of 0.30 g/mi. This

is effectively the LEV NOX emission

standard for LDVs and LDT1s under the

NLEV program.58 This interim program

will hold LDVs and LLDTs to NLEV

levels if they are not yet subject to Tier

2 standards during the phase-in. By

implementing these interim standards

for LDVs and LLDTs we will ensure that

the accomplishments of the NLEV

program continue. Additionally, this

program will bring about substantial

and important NOX emission reductions

from LDT2s in the early years of the

program. LDT2s will be held to a 0.3 g/

mi NOX average in contrast to a 0.5 g/

mi average in the NLEV program.

Because the Tier 2 standards are

phased-in beginning in the 2004 model

year, the interim standards for LDVs and

LLDTs apply to fewer vehicles each

year, i.e., they are ‘‘phase-out’’

standards. Table IV.B–2 shows the

maximum percentage of LDVs and

LLDTs subject to the interim standards

each year— 75% in 2004, 50% in 2005,

25% in 2006 and 0% in 2007.

As mentioned above, the interim

program for LDV/LLDTs is designed to

hold these vehicles to the NLEV NOX

level for LDVs and LDT1s, and a few of

our bins are derived from the NLEV

program. Our proposal to bring LDT2s

into line with the LDVs and LDT1s

during the interim program by requiring

all LDVs, LDT1s and LDT2s to meet the

same average NOX standard (0.30) g/mi

was of concern to industry commenters.

In the final rule, we are retaining this

requirement, but we are providing an

optional NMOG standard of 0.130 for

LDT2s certified to bin 9 when the

manufacturers of those LDT2s elect to

bring all of their 2004 model year

6738 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

59 In the Tier 1 program, exhaust hydrocarbon

standards are in terms of NMHC, not NMOG.

However, as we have explained elsewhere in this

preamble, NMHC and NMOG results are very

similar for gasoline and diesel-fueled vehicles.

HLDTs under our interim program and

phase 25% of those HLDTs into the 0.20

g/mi average NOX standard. (See ii.

below). These provisions are discussed

in detail below and also in the Response

to Comments document.

ii. Interim Exhaust Emission Standards

for HLDTs

Our interim standards for HLDTs will

begin in the 2004 model year similar to

our proposal in the NPRM. The Interim

Program for HLDTs will require

compliance with a corporate average

NOX standard of 0.20 g/mi that will be

phased in between 2004 and 2007. The

interim HLDT standards, like those for

LDV/LLDTs will make use of the bins in

Tables IV.B. –4 and –5. We believe that

our interim standards, which start in

2004, will produce significant emission

reductions from HLDTs produced

during the interim period. For example,

HLDTs will have to reduce emissions in

the interim program relative to the

NLEV program. These standards, by

themselves, represent a major reduction

in emission standards and we believe it

is likely that some manufacturers will

apply their Tier 2 technology to HLDTs

in order to comply with the interim

standards.

As shown in Table IV.B.–3, the phasein schedule for HLDTs to the 0.20 g/mi

corporate average NOX standard will be

25 percent in the 2004 model year

(except as noted below), 50 percent in

2005, 75 percent in 2006, and 100

percent in 2007. As for the Tier 2

standards, alternative phase-in

schedules (see Section IV.B.4.b.ii.) will

be available. The interim program will

remain in effect through 2008 to cover

those HLDTs not yet phased into the

Tier 2 standards (a maximum of 50%).

Interim HLDTs not subject to the

interim corporate average NOX standard

during the applicable phase-in years

(2004–2006 or 2005–2006) will be

subject to the least stringent bins so

their NOX emissions will be effectively

capped at 0.60 g/mi. These vehicles will

be excluded from the calculation to

determine compliance with the interim

0.20 g/mi average NOX standard.

This approach will allow more time

for manufacturers to bring the more

difficult HLDTs to Tier 2 levels while

achieving real reductions from those

HLDTs that may present less of a

challenge.

Due to statutory leadtime

considerations, we were not able to

finalize the HLDT standards to be in

effect by the time the 2004 model year

begins. For this reason, we are providing

incentives for HLDTs to comply with

the Tier 2 standards for all 2004 model

year HLDTs. This change and the

leadtime issue are discussed further

under section IV.B.4.e. below and also

in the Response to Comments

document.

iii. Interim Programs Will Provide

Reductions Over Previous Standards

As is the case with the primary Tier

2 standard structure, the interim

programs will focus on NOX but will

also provide reductions in NMOG

beyond the NLEV program. This is

because the interim programs will

reduce emissions from LDT2s and

HLDTs compared to their previous

standards. Without the interim

standards, HLDTs could be certified to

the Tier 1 NMHC levels (0.46 g/mi or

0.56 g/mi). With the interim standards,

however, exhaust NMOG 59 should

average approximately 0.09 g/mi for all

non-Tier 2 LDV/LLDTs and 0.24 g/mi or

less for HLDTs. CO under Tier 1 could

be as high as 7.3 g/mi for LDT4s. Under

the interim program, CO standards for

most bins will be well below 7.3 g/mi.

f. Generating, Banking, and Trading NOX

Credits

As proposed in the NPRM and

finalized in this notice, manufacturers

will be permitted to average the NOX

emissions of their Tier 2 vehicles and

comply with a corporate average NOX

standard. In addition, when a

manufacturer’s average NOX emissions

fall below the corporate average NOX

standard, it can generate NOX credits for

later use (banking) or to sell to another

manufacturer (trading). NOX credits will

be available under the Tier 2 standards,

the interim standards for LDVs and

LLDTs, and the interim standards for

HLDTs. These NOX credit provisions

will facilitate compliance with the fleet

average NOX standards and be very

similar to those currently in place for

NMOG emissions under California and

federal NLEV regulations.

A manufacturer with an average NOX

level for its Tier 2 vehicles in a given

model year below the 0.07 gram per

mile corporate average standard can

generate Tier 2 NOX credits that it can

use in a future model year when its

average NOX might exceed the 0.07

standard. Manufacturers must calculate

their corporate average NOX emissions

at year end and then compute credits

generated based on how far below 0.07

g/mi the corporate average falls.

Manufacturers will be free to retain

any credits they generate for future use

or to trade (sell) those credits to other

manufacturers. Credits retained or

purchased can be used by

manufacturers with corporate average

Tier 2 NOX levels above 0.07 g/mi.

Under provisions described in Section

IV.B.4.d.iv., manufacturers can

implement NOX emission reductions as

early as the 2001 model year and earn

early Tier 2 NOX credits to help LDVs

and LLDTs meet Tier 2 standards.

Similarly, manufacturers can earn early

credits for HLDTs as early as the 2001

model year. In model years up through

2005, manufacturers can earn extra

credits when they certify vehicles to

bins 1 or 2.

Banking and trading of NOX credits

under the interim non-Tier 2 standards

will be similar to that under the Tier 2

standards, except that a manufacturer

must determine its credits based upon

the 0.30 or 0.20 gram per mile corporate

average NOX standard applicable to

vehicles in the interim programs. As we

proposed in the NPRM, interim credits

from LDVs/LLDTs and interim credits

from HLDTs will not be permitted to be

used interchangeably due to the

differences in the interim corporate

average NOX standards. As proposed in

the NPRM, there will be no provisions

for early banking under the interim

standards and manufacturers will not be

allowed to use interim credits to address

the Tier 2 NOX average standard. This

is because we remain concerned that

credits can be generated relatively easily

under less stringent standards (the Tier

1 or interim standards) and then used in

such a way to delay implementation of

the Tier 2 standards.

Banking and trading of NOX credits

and related issues are discussed in

greater detail in Section IV.B.4.d. below.

2. Why Are We Finalizing the Same Set

of Standards for Tier 2 LDVs and LDTs?

Before we provide a more detailed

description of the vehicle program, we

want to review two overarching

principles of today’s rule. The first is

our goal to bring all LDVs and LDTs

under the same set of emission

standards. Historically, LDTs—and

especially the heavier trucks in the

LDT3 and LDT4 categories—have been

subject to less stringent emission

standards than LDVs (passenger cars). In

recent years the proportion of light truck

sales has grown to approximately 50

percent. Many of these LDTs are

minivans, passenger vans, sport utility

vehicles and pick-up trucks that are

used primarily or solely for personal

transportation; i.e., they are used like

passenger cars.

As vehicle preferences have

increasingly shifted from passenger cars

to light trucks there has been an

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6739

60Because of the different phase-in percentages

and phase-in schedules for the two groups, during

the duration of the phase-in (through 2008),

manufacturers will average Tier 2 LDV/LLDTs

separately from HLDTs.

61The Alliance proposed NMHC standards in lieu

of the NMOG standards we proposed and are

finalizing today. We are including a provision in

the final rule to accept NMHC results, subject to an

adjustment factor, to demonstrate compliance with

NMOG standards, although we are not adopting the

fixed standards proposed by the Alliance.

62The interim PM standard in this new bin,

which represents a reduction from the NLEV PM

standards, should be feasible without

aftertreatment. The technologies needed to meet the

PM standard we proposed for this bin would likely

have required low sulfur diesel fuel, which may not

be widely available during the interim program.

This change is also discussed in section V.A.

accompanying increase in emissions

over what otherwise would have

occurred because of the increase in

miles traveled by LDTs and the less

stringent standards for LDTs as

compared to LDVs. As Section III. above

makes clear, reductions in these excess

emissions (and in other mobile and

stationary source emissions) are

seriously needed. Since both LDVs and

LDTs are within technological reach of

the standards in the Tier 2 bin structure,

and since none of the comments have

been persuasive that manufacturers can

not meet the standards, we are finalizing

our proposal to equalize the regulatory

useful life mileage for LDVs and LDTs

and apply the same Tier 2 exhaust

emission standard bins to all of them.

This program will ensure that

substantial reductions occur in all

portions of the light-duty fleet and that

the movement from LDVs to LDTs will

not counteract these reductions.

Once the phase in periods end for all

vehicles in 2009, manufacturers will

include all LDVs and LDTs together in

calculating their corporate average NOX

levels.60 As mentioned above and

described in more detail in Section

IV.B.–4. below, manufacturers can

choose the emission bin for any test

group of vehicles provided that, on a

sales weighted average basis, the

manufacturer meets the average NOX

standard of 0.07 g/mi for its Tier 2

vehicles that year.

Some manufacturers have suggested

that a program with different

requirements is needed for heavy LDTs.

Recognizing that compliance will be

most challenging for HLDTs, the delay

in the start of the phase-in and the

additional phase-in years for those

vehicles will allow manufacturers to

delay the initial impact of the Tier 2

standards until the 2008 model year.

This represents four additional model

years of leadtime beyond the time when

passenger cars and LDT1s and LDT2s

will achieve Tier 2 standards in

substantial numbers. We believe this

phase-in and other provisions of this

rule respond to these concerns. Note

that in the NPRM, we requested

comments on the need for different

hydrocarbon standards for these

vehicles recognizing that a tradeoff often

exists between HC and NOX emissions.

We also proposed that several bins have

higher hydrocarbon standards for

HLDTs during the interim program. We

are finalizing these bins as proposed.

Also, as an option, we are permitting the

use of NMOG values similar to those in

the NLEV program for bins 9 and 10

only for certain LDT2s and LDT4s

during the interim program (see section

IV.B.1.e.ii. above for details).

We are not adopting the Alliance’s

proposed phase-in schedule which

would have provided a phase-in lasting

until 2011. At the end of the Alliance’s

proposed phase-in, all vehicles would

comply with an average NOX standard

of 0.07 g/mi. A fixed 0.09 NMHC

standard would apply to LDVs and

LLDTs while a fixed 0.156 NMHC

standard would apply to HLDTs.61 Our

final program provides HLDTs until

2008 before any have to meet 0.07 g/mi

on average and permits them to be

averaged with LDV/LLDTs beginning in

2009, when all must meet 0.07 g/mi

NOX on average. We believe that eight

years is a significant amount of leadtime

to apply Tier 2 technology. We heard

clearly from the public hearings and

written comments that the public sees

no justification for and does not want

even more time provided for HLDTs.

Furthermore, we see no technological

need for more time than we proposed.

Indeed, many believe that HLDTs

should meet the Tier 2 standards in step

with the LDV/LLDTs.

We are not promulgating the fixed

NMHC standards suggested by the

Alliance, but are sticking with the

concept of bins containing lower NMOG

standards connected to lower NOX (and

other) standards. We believe that

providing final exhaust emission

standards for HLDTs that deviate from

those for LDV/LLDTs would violate one

of the overarching principles of the Tier

2 program, i.e. that all LDVs and LDTs

should be subject to the same exhaust

emission standards. Further, the idea of

NMOG values that differ from

California’s runs counter to other

arguments raised by the Alliance that

EPA should align bins with California’s

to promote 50 state certification of test

groups.

3. Why Are We Finalizing the Same

Standards for Both Gasoline and Diesel

Vehicles?

The second overarching principle of

our vehicle program is the use of the

same Tier 2 standards for all LDVs and

LDTs, regardless of the fuel they are

designed to use. The same exhaust

emission standards and useful life

periods we are finalizing today will

apply whether the vehicle is built to

operate on gasoline or diesel fuel or on

an alternative fuel such as methanol or

natural gas. Diesel powered LDVs and

LDTs tend to be used in the same

applications as their gasoline

counterparts, and thus we believe they

should meet the same standards. Less

stringent standards for diesels could

create incentives for manufacturers to

build more diesel vehicles, thus

endangering the emission reductions

expected by this program.

Manufacturers have expressed

concerns that diesel-fueled vehicles

would have difficulty meeting NOX and

particulate matter levels like those

contained in today’s rule. Clearly, these

standards will be challenging. As

discussed in Section IV.A.–1. above, we

expect that the Tier 2 NOX and NMOG

standards will be challenging for

gasoline vehicles, but that major

technological innovations will not be

required. For diesels, however, the final

Tier 2 NOX and PM standards will likely

require applications of aftertreatment,

most likely accompanied by changes in

diesel fuel as such devices are sensitive

to diesel fuel quality, particularly sulfur

content. We do not believe such devices

will be necessary to meet the top bin for

our interim standards.62 Given the small

percentage of diesel vehicles and the

phase-in of the standards, that bin

should be sufficient for any

manufacturer to market diesels and still

comply with the interim program. We

anticipate that manufacturers that

choose to build diesel vehicles for the

final Tier 2 standards will adopt

aftertreatment technologies such as NOX

adsorber catalysts and continuously

regenerating particulate traps to meet

Tier 2 requirements. We issued an

Advanced Notice of Proposed

Rulemaking to seek input on potential

diesel fuel quality changes on May 13,

1999 (64 FR 26142). We anticipate

issuing a Notice of Proposed

Rulemaking to reduce the sulfur limit

on diesel fuel in the spring of 2000

followed by a final rule in late 2000.

Our goal in that rulemaking is to have

low sulfur diesel fuel available which

will allow diesel vehicles to meet the

Tier 2 standards, within the bin

structure, by the time the Tier 2

standards are required for the entire

fleet.

6740 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

63A ‘‘test group’’ is the basic classification unit

for certification of light-duty vehicles and trucks

under EPA certification procedures for the

CAP2000 program. ‘‘Test group’’ is a broader

classification unit than ‘‘engine family’’ used prior

to the implementation of the CAP2000 program. We

discuss the CAP2000 program in more detail in

section V.A.9. of this preamble.

64The regulatory ‘‘useful life’’ value for Tier 2

vehicles is specifically addressed in Section V.A.2.

of this preamble. Full useful life will be 10 years

or 120,000 miles for all vehicles except LDT3s and

LDT4s, for which it is 11 years or 120,000 miles.

Intermediate useful life, where standards are

applicable, is 5 years or 50,000 miles.

65EPA’s current standards for Clean Fuel

Vehicles are less stringent than the Tier 2 standards.

See 40 CFR 88.104–94. The Tier 2 standards will

supercede the current CFV standards, and the

Agency intends to undertake a rulemaking to revise

the CFV standards accordingly.

66 In some cases our bins do not match

California’s exactly, because they have higher

NMOG standards. These bins ‘‘cover’’ the California

bin in that a vehicle certified to the California

standards will comply with the standards in these

bins.

Today, diesels comprise less than

one-half of one percent of all LDV/LDT

sales. While this is a small fraction, the

potential exists for diesels to gain a

considerable market share in the future.

All one need do is review the dramatic

increase in recent years of diesel engine

use in the lightest category of heavy

duty vehicles (8500–10,000 pounds

GVWR) to see the potential for

significant diesel engine use in LDTs,

and perhaps LDVs, in the future. Just

ten years ago, diesels made up less than

10 percent of this class of vehicles. In

1998, this fraction approached 50

percent.

The potential impact of large-scale

diesel use in the light-duty fleet

underscores the need for the same

standards to apply to diesels as other

vehicles. Given the health concerns

associated with diesel PM emissions

(see Section III. above), we believe that

it is prudent to address PM emissions

from diesel LDVs and LDTs while their

numbers are relatively small. In this

way the program can minimize the PM

impact that would accompany

significant growth in this market

segment while allowing manufacturers

to incorporate low-emission technology

into new light-duty diesel engine

designs.

4. Key Elements of the Vehicle Program

The previous subsections IV.B.–1.2.

and 3. provide an overview of the Tier

2 vehicle program and the two key

principles it is built on. This subsection

elaborates on the major vehicle-related

elements of today’s rule. Later in this

preamble, Section V.A. discusses the

rest of the vehicle provisions.

a. Basic Exhaust Emission Standards

and ‘‘Bin’’ Structure

Our final Tier 2 program contains a

basic requirement that each

manufacturer meet, on average, a full

useful life NOX standard of 0.07 g/mi for

all its Tier 2 LDVs and LDTs.

Manufacturers will have the flexibility

to choose the set of standards that a

particular test group 63 of vehicles must

meet. For a given test group of LDVs or

LDTs, manufacturers will select a set of

full useful life 64 standards from the

same row (‘‘emission bin’’ or simply

‘‘bin’’) in Table IV.B.–4. below. Each bin

contains a set of individual NMOG, CO,

HCHO, NOX, and PM standards. For

technology harmonization purposes, our

proposed emission bins include or

otherwise cover all of those adopted in

California’s LEV II program.65,66

In the NPRM, we proposed that

interim vehicles and Tier 2 vehicles

(except for those Tier 2 vehicles in the

lowest bins) would also have to meet

intermediate useful life standards, i.e.,

standards that apply for 5 years or

50,000 miles. We are finalizing these

intermediate useful life standards as

proposed. Where we have added new

full life bins, we have included

corresponding intermediate life bins as

appropriate. Our intermediate life

standards are generally aligned with

California’s, they only impact the higher

bins, and we do not believe they add

substantial burden to the program.

Further, they provide a check on the

allowed emission deterioration during

the life of the vehicle. For the final rule,

we have made two changes involving

intermediate life standards. First, we are

providing that diesel vehicles, which

will likely certify to bin 10 during the

interim program, may opt not to meet

the intermediate life standards

associated with this bin. Low sulfur

diesel fuel may be needed for diesels to

meet our interim intermediate life

standards and it is not likely to be

widely available during the time frame

of the interim program. Secondly, for all

vehicles, we are finalizing a provision

that will make intermediate life

standards optional for any test group

that is certified to a full useful life of

150,000 miles. This provision is

described in more detail with other

useful life issues in section V.B.

TABLE IV.B–4.—TIER 2 LIGHT–DUTY FULL USEFUL LIFE EXHAUST EMISSION STANDARDS

[Grams per mile]

Bin No. NOX NMOG CO HCHO PM Comments

10 ............................................... 0.6 0.156/0.230 4.2/6.4 ......... 0.018/0.027 0.08 (a,b,c,d)

9 ................................................. 0.3 0.090/0.180 4.2 ............... 0.018 ........... 0.06 (a,b,e)

The above temporary bins expire in 2006 (for LDVs and LLDTs) and 2008 (for HLDTs)

8 ................................................. 0.20 0.125/0.156 4.2 ............... 0.018 ........... 0.02 (b,f)

7 ................................................. 0.15 0.090 ........... 4.2 ............... 0.018 ........... 0.02

6 ................................................. 0.10 0.090 ........... 4.2 ............... 0.018 ........... 0.01

5 ................................................. 0.07 0.090 ........... 4.2 ............... 0.018 ........... 0.01

4 ................................................. 0.04 0.070 ........... 2.1 ............... 0.011 ........... 0.01

3 ................................................. 0.03 0.055 ........... 2.1 ............... 0.011 ........... 0.01

2 ................................................. 0.02 0.010 ........... 2.1 ............... 0.004 ........... 0.01

1 ................................................. 0.00 0.000 ........... 0.0 ............... 0.000 ........... 0.00

Notes:

aBin deleted at end of 2006 model year (2008 for HLDTs).

bThe higher temporary NMOG, CO and HCHO values apply only to HLDTs and expire after 2008.

cAn additional temporary higher bin restricted to MDPVs is discussed in section IV.B.4.g.

dOptional temporary NMOG standard of 0.280 g/mi applies for qualifying LDT4s and MDPVs only.

eOptional temporary NMOG standard of 0.130 g/mi applies for qualifying LDT2s only, see text.

f Higher temporary NMOG standard is deleted at end of 2008 model year.

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6741

TABLE IV.B.–5.—LIGHT-DUTY INTERMEDIATE USEFUL LIFE (50,000 MILE) EXHAUST EMISSION STANDARDS

[Grams per mile]

Bin No. NOX NMOG CO HCHO PM Comments

10 ............................................... 0.4 0.125/0.160 3.4/4.4 ......... 0.015/0.018 (a,b,c,d,f,h)

9 ................................................. 0.2 0.075/0.140 3.4 ............... 0.015 ........... (a,b,e,h)

The above temporary bins expire in 2006 (for LDVs and LLDTs) and 2008 (for HLDTs)

8 ................................................. 0.14 0.100/0.125 3.4 ............... 0.015 ........... (b,g,h)

7 ................................................. 0.11 0.075 ........... 3.4 ............... 0.015 ........... (h)

6 ................................................. 0.08 0.075 ........... 3.4 ............... 0.015 ........... (h)

5 ................................................. 0.05 0.075 ........... 3.4 ............... 0.015 ........... (h)

Notes:

aBin deleted at end of 2006 model year (2008 for HLDTs).

bThe higher temporary NMOG, CO and HCHO values apply only to HLDTs and expire in 2008.

cAn additional higher temporary bin restricted to MDPVs is discussed in section IV.B.4.g.

dOptional temporary NMOG standard of 0.195 g/mi applies for qualifying LDT4s and MDPVs only.

eOptional temporary NMOG standard of 0.100 g/mi applies for qualifying LDT2s only, see text.

f Intermediate life standards are optional for diesels certified to bin 10.

g Higher temporary NMOG value deleted at end of 2008 model year.

h. Intermediate life standards are optional for any test group certified to a 150,000 mile useful life (if credits are not claimed).

Under a ‘‘bins’’ approach, a

manufacturer may select a set of

emission standards (a bin) to comply

with, and a test group must meet all

standards within that bin. Ultimately,

the manufacturer must also ensure that

the emissions of a targeted pollutant—

NOX in this case—from all of its

vehicles taken together meet a

‘‘corporate average’’ emission standard.

This corporate average emission

standard ensures that a manufacturer’s

production yields the required overall

emission reductions. (See Section IV.B.–

4.c. below for more discussion of the

corporate average NOX standard.)

In addition to the Tier 2 standards

described above, we are also finalizing

an interim average NOX standard

derived from the LDV/LDT1 NLEV

program to cover all non-Tier 2 LDVs

and LLDTs during the Tier 2 phase-in.

We are finalizing a separate interim

average NOX standard for HLDTs. As in

the Tier 2 program, manufacturers will

select bins from Table IV.B.–4 to use to

comply with the interim standards. Bins

with NOX values at or above 0.07 g/mi

also have associated intermediate life

standards which are shown in Table

IV.B.–5. (We describe the interim

standards in detail in Section IV.B.4.e.

below.)

i. Why Are We Including Extra Bins?

Compared to the CalLEV II program,

our Tier 2 proposal included additional

bins. The California program contains

no bins that will allow NOX levels above

the 0.07 g/mi level. Therefore, under the

California program, no engine family

can be certified above 0.07 g/mi, even

with the application of offsetting

credits. We proposed to add two bins

(with NOX values of 0.15 and 0.20)

above the 0.07 bin and another below

(with a NOX value of 0.04) to provide

manufacturers with additional

flexibility. Based upon comments

received from the Alliance and others

that additional bins provide important

added flexibility, we are finalizing a

total of three bins above the LEV level

(the additional bin has a NOX value of

0.10 g/mi) and are adding one more

below the LEV level (this additional bin

has a NOX value of 0.03 g/mi). Due to

the NOX averaging requirement of this

rule, these bins will not result in any

increase in NOX emissions. Further,

these bins will address concerns raised

by some that a wider variety of bins, and

bins with higher NOX values, are

needed to avoid a situation where the

Tier 2 program discourages the

development of advanced technology

high fuel economy vehicles, which may,

at least in their earliest years, have NOX

emissions higher than more

conventional vehicles.

In our NPRM we proposed that during

the Tier 2 phase-in years (through 2006

for LDV/LLDTs and 2008 for HLDTs),

bins from the applicable interim

program would be available to enhance

the flexibility of the program by

providing manufacturers with

additional bins having NOX standards

above 0.07 g/mi. In the NPRM, we

showed the interim bins in separate

tables for LDV/LLDTs and HLDTs.

There was considerable overlap across

the two tables and with the Tier 2 bins.

In this final rule, we have consolidated

the interim bins and the Tier 2 bins into

one table for simplicity and ease of

reference. The interim programs for

non-Tier 2 vehicles are described in

detail in section IV.B.4.e.

While some commenters were

concerned about the existence of bins

above NOX = 0.07 g/mi, we believe that

the additional higher bins actually

provide incentive for manufacturers to

produce vehicles below 0.07 g/mi of

NOX. We believe this incentive exists

because manufacturers will have some

vehicles (especially larger LDTs) that

they might find more cost effective to

certify to levels above the 0.07 g/mi

average standard. However, to do this

they will have to offset those vehicles in

our NOX averaging system with vehicles

certified below 0.07 g/mi. The bins at

NOX = 0.04 g/mi and NOX = 0.03 g/mi

will provide greater opportunity to do

this. Thus, the extra bins serve two

purposes; they provide additional

flexibility to manufacturers to address

technological differences and costs, and

they provide those manufacturers with

incentives to produce cleaner vehicles

and thus advance emission control

technology.

We are finalizing a bins approach

with the bins shown in Tables IV.B.4

and 5 to provide adequate and

appropriate emission reductions and

manufacturer flexibility. This structure

will help to accelerate technological

innovation. We requested comment on

whether we should include up to two

additional bins between NOX = 0.07 and

NOX = 0.15. Based upon manufacturer

comment, we have added an additional

bin (bin 6 ) with NOX = 0.10. This bin

will provide greater flexibility for

manufacturers who may find it more

cost-effective to produce some vehicles

slightly above 0.07 but have difficulties

meeting a 0.07 g/mi average NOX

standard if they must certify them to a

NOX level of 0.15 g/mi.

We requested comment on whether

our Tier 2 bin in the NPRM with NOX

= 0.20 (our final bin 8) should be

eliminated when the Tier 2 phase-in is

completed (after 2007 for LDV/LLDTs

6742 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

67For Tier 2 vehicles (and for interim vehicles),

the term ‘‘U.S. sales’’ means, for a given model year,

those sales in states other than California and any

states that have adopted the California program.

and after 2009 for HLDTs). Numerous

commenters argued that our highest

bins were too lenient. Comments from

manufacturers were opposed to

eliminating bin 8 and we see little

downside to having bins higher than the

0.07 NOX standard, given that, for all of

the vehicles that will use this bin,

manufacturers will have to offset the

excess emissions by selling vehicles

certified below 0.07 g/mi NOX under the

averaging requirement. Thus, we are

retaining bin 8.

b. The Program Will Phase in the Tier

2 Vehicle Standards Over Several Years

i. Primary Phase-In Schedule

We are finalizing as proposed our

plan to phase in the Tier 2 standards for

LDV/LLDTs over a four year period

beginning in 2004 and we are also

finalizing as proposed a delayed two

year phase-in beginning in 2008 for

HLDTs. These phase-in schedules are

shown in Table IV.B.–2 and are also

shown separately in Tables IV.B.–6 and

7. We believe the flexibility of this dual

phase-in approach is appropriate

because the Tier 2 program will

encompass all light-duty vehicles and

trucks and will result in widespread

applications of upgraded and improved

technology across the fleet. The program

will require research, development,

proveout, and certification of all lightduty models, and manufacturers may

need longer lead time for some vehicles,

especially HLDTs. Also, manufacturers

may wish to time compliance with the

Tier 2 standards to coincide with other

changes such as the roll out of new

engines or new models. In order to

begin the introduction of very clean

vehicles as soon as possible while

avoiding imposing unnecessary

inefficiencies on vehicle manufacturers,

we believe this practical but aggressive

phase-in schedule effectively balances

air quality, technology, and cost

considerations.

In each year, manufacturers will have

to ensure that the specified fraction of

their U.S. sales: 67

• Meets Tier 2 standards for exhaust

emissions, including Supplemental

Federal Test Procedure (SFTP)

standards (discussed in Section V.A.–3.

below);

• Meets Tier 2 standards for

evaporative emissions (discussed in

Section IV.B.–4.f. below); and

• Meets the corporate average Tier 2

NOX standard.

Manufacturers will have to meet the

Tier 2 exhaust requirements (i.e., all the

standards of a particular bin plus the

SFTP standards) using the same

vehicles. Vehicles not covered by the

Tier 2 standards during the phase-in

years (2004–2008) will have to meet

interim standards described in Section

IV.B.4.e. below and the existing

evaporative emission as well as the

applicable SFTP standards.

Manufacturers can elect to meet the

percentage phase-in requirements for

evaporative and exhaust emissions

using two different sets of vehicles. We

believe that because of interactions

between evaporative and exhaust

control strategies, manufacturers will

generally address the Tier 2 evaporative

phase-in with the same vehicles that

they use to meet the exhaust phase-in.

However, the primary focus of today’s

proposal is on exhaust emissions, and

the flexibility for manufacturers to use

different sets of vehicles in complying

with the phase-in schedule for

evaporative standards and for the

exhaust standards will have no

environmental down side that we are

aware of. It is possible that some

exhaust emission improvements might

even occur sooner than they otherwise

would if a manufacturer is able to move

ahead with the roll-out of a model with

cleaner exhaust emissions without

having to wait for the development of

suitable evaporative controls to be

completed for that model.

TABLE IV.B.–6.—PRIMARY PHASE-IN

SCHEDULE FOR SALES OF TIER 2

LDVS AND LLDTS

Model year

Required percentage of

light-duty vehicles and light

light-duty

trucks

(percent)

2004 ...................................... 25

2005 ...................................... 50

2006 ...................................... 75

2007 ...................................... 100

TABLE IV.B.–7.—PRIMARY PHASE-IN

SCHEDULE FOR SALES OF TIER 2

HLDTS

Model year

Required percentage of

heavy lightduty trucks

(percent)

2008 ...................................... 50

2009 ...................................... 100

We are finalizing our proposed phasein approach, in which vehicle sales will

be determined according to the ‘‘point

of first sale’’ method outlined in the

NLEV rule. Vehicles with points of first

sale in California or a state that has

adopted the California LEV II program

(if any) will be excluded from the

calculation. The ‘‘point of first sale’’

method recognizes that most vehicle

sales will be to dealers and that the

dealers’ sales will generally be to

customers in the same geographic area.

While some sales to California residents

(or residents of states that adopt

California standards) may occur from

other states and vice-versa, we believe

these sales will be far too small to have

any significant impact on the air quality

benefits of the Tier 2 program or the

manufacturers’ ability to demonstrate

compliance.

ii. Alternative Phase-In Schedule

We are finalizing, as proposed, that

manufacturers may introduce vehicles

earlier than required to earn the

flexibility to make offsetting

adjustments, on a one-for one basis, to

the phase-in percentages in later years.

However, they will still need to reach

100% of sales in the 2007 model year

(2009 for HLDTs). Manufacturers will

have the option to use this alternative to

meet phase-in requirements for LDV/

LLDTs and/or HLDTs. They can use

separate alternative phase-in schedules

for exhaust and evaporative emissions,

or an alternative phase-in schedule for

one set of standards and the primary

(25/50/75/100% or 50%/100%)

schedule for the other.

Under these alternative schedules,

manufacturers will have to introduce

vehicles that meet or surpass the 0.07 g/

mi Tier 2 NOX average standard before

they are required to do so, or else

introduce vehicles that meet or surpass

the 0.07 standard in greater quantities

than required. Alternative phase-in

schedules essentially credit the

manufacturer for its early or accelerated

efforts and allow the manufacturer

greater flexibility in subsequent years

during the phase-in. Thus, the

alternative phase-in schedule provisions

provide incentive and flexibility to

manufacturers to introduce Tier 2

vehicles before 2004 (or 2008 for

HLDTs).

As outlined in the NPRM, an

alternative phase-in schedule will be

acceptable if it passes a specific

mathematical test. We have designed

the test to provide manufacturers benefit

from certifying to the Tier 2 standards

early while ensuring that significant

numbers of Tier 2 vehicles are

introduced during each year of the

alternative phase-in schedule. To test an

alternative schedule, a manufacturer

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6743

68For interim vehicles, this average NOX standard

will be 0.20 for HLDTs and 0.30 for LDV/LLDTs.

Compliance with these interim average standards will be calculated in the same manner as

compliance with the 0.07 standard.

must sum its yearly percentages of Tier

2 vehicles beginning with model year

2001 and compare the result to the sum

that results from the primary phase-in

schedule. If an alternative schedule

scores as high or higher than the base

option, then the alternative schedule is

acceptable. The mathematical technique

to evaluate alternative phase-in schemes

is somewhat similar to that used in our

NLEV rule and in California rules.

For LDV/LLDTs, the final sum of

percentages must equal or exceed 250—

the sum that results from a 25/50/75/

100 percent phase-in. For example, a

10/25/50/65/100 percent phase-in that

begins in 2003 will have a sum of 250

percent and is acceptable. In this

example, assuming constant levels of

production, each Tier 2 vehicle sold

early (i.e. in 2003) will permit the

manufacturer to sell one less Tier 2

vehicle in the last phase-in year (2006).

A 10/20/40/70/100 percent phase-in

that begins the same year has a sum of

240 percent and is not acceptable. For

HLDTs, the sum must equal or exceed

150 percent.

To ensure that significant numbers of

Tier 2 vehicles are introduced in the

2004 time frame, manufacturers will not

be permitted to use alternative phase-in

schedules that delay the

implementation of the Tier 2 LDV/LLDT

requirements, even if the sum of the

phase-in percentages meets or exceeds

250. Such a situation could occur if a

manufacturer delayed implementation

of its Tier 2 production until 2005 and

began a 75/85/100 percent phase-in that

year. To protect against this possibility,

we are finalizing the proposed

requirement that for any alternative

phase-in schedule, a manufacturer’s

phase-in percentages from the 2004 and

earlier model years sum to at least 25%.

In the final rule we are including an

additional measure of flexibility to the

requirements for alternative phase-in

schedules. We will permit

manufacturers to achieve a 2004 phasein of less than 25%, but no less than

20%, provided that in 2005 they make

up the shortfall in a two-for-one

manner. So, as an example, a

manufacturer that phased in 5% in 2003

and 15% in 2004 would achieve a total

of 20% through the 2004 model year

and would need to comply with Tier 2

requirements for at least 60% of its

LDV/LLDTs in 2005. We believe that

this flexibility is appropriate because

the required response for 2005 model

year vehicles more than makes up for

the environmental loss from the 2004

model year vehicles.

We requested comment on whether

alternative phase-in schedules should

be structured to permit manufacturers to

extend phase in past the final year of the

primary phase-in schedule (2007 or

2009). While the Alliance proposal and

comments clearly support phase-ins that

run past 2007 and 2009, other

commenters were opposed to any

extensions of the phase-in period. In

fact most commenters who addressed

the length of the phase-in indicated, as

previously discussed, that the phase-in

for HLDTs should be moved ahead to

2007 to coincide with LDV/LLDTs. We

are not finalizing any provisions that

will permit alternative phase-in

schedules to provide additional time for

manufacturers to meet any final 100%

compliance year.

In the NPRM, we pointed out that

phase-in schedules, in general, add little

flexibility for manufacturers with

limited product offerings because a

manufacturer with only one or two test

groups can not take full advantage of a

25/50/75/100 percent or similar phasein. For manufacturers meeting EPA’s

definition of ‘‘small volume

manufacturer,’’ we proposed to exempt

those manufacturers from the phase-in

schedules and require them to simply

comply with the final 100% compliance

requirement. We are finalizing this

provision for small volume

manufacturers. This provision is only

intended to apply to small volume

manufacturers and not to small test

groups of larger manufacturers.

For larger manufacturers having a

limited product line, we recognize that

our phase-in schedule may lack

flexibility, however, we are not

including any provisions to address this

issue as we are for small volume

manufacturers because we do not

believe these manufacturers need the

relief and we do not want to sacrifice

any air quality benefits of the program.

c. Manufacturers Will Meet a ‘‘Corporate

Average’’ NOX Standard

While the manufacturer will be free to

certify a test group to any applicable bin

of standards in Table IV.B.–2, it will

have to ensure that the sales-weighted

average of NOX standards from all of its

test groups of Tier 2 vehicles meet a full

useful life standard of 0.07 g/mi.68

Using a calculation similar to that for

the NMOG corporate average standard

in the California and NLEV programs,

manufacturers must determine their

compliance with the corporate average

NOX standard at the end of the model

year by computing a sales weighted

average of the full useful life NOX

standards from each bin. Manufacturers

must use the following formula:

Corporate total Tier Average NO Tier 2 NO std for each bin) (sales for each bin)

 sales X

X = ∑( ×

2

Manufacturers must exclude vehicles

sold in California or states adopting

California LEV II standards from the

calculation. As indicated above,

manufacturers must compute separate

NOX averages for LDV/LLDTs and

HLDTs through model year 2008.

The corporate average NOX standards

of the primary Tier 2 program and the

interim programs for LDV/LLDTs and

HLDTs will ensure that expected fleetwide emission reductions are achieved.

At the same time, the corporate average

standards allow us to permit the sale of

some vehicles above the levels of the

average standards to address the greater

technological challenges some vehicles

face and to reduce the overall costs of

the program. We discuss how

manufacturers can generate, use, buy

and sell NOX credits under the interim

and Tier 2 programs in the next

subsection.

Given the corporate average NOX

standards, we do not believe a corporate

average NMOG standard as used by

California is essential because meeting

the corporate average NOX standard will

automatically bring the NMOG fleet

average to approximately 0.09 g/mi or

below.

d. Manufacturers Can Generate, Bank,

and Trade NOX Credits

i. General Provisions

As mentioned in the Overview above,

we are finalizing our proposal that

manufacturers with year-end corporate

average NOX emissions for their Tier 2

vehicles below 0.07 g/mi can generate

Tier 2 NOX credits. Credits can be saved

(banked) for use in a future model year

6744 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

or for trading (sale) to another

manufacturer. Manufacturers can use

credits if their corporate average NOX

emissions are above 0.07 g/mi.

As proposed, the Tier 2 standards will

apply regardless of the fuel the vehicle

is designed for, and there will be no

restrictions on averaging, banking or

trading of credits across vehicles of

different fuel types. Consequently, a

gasoline fueled LDV might help a

manufacturer generate NOx credits in

one year that could be banked for the

next year when they could be used to

average against NOX emissions of a

diesel fueled LDT within the

appropriate averaging structure.

Because of the split phase-in and the

different interim programs we are

finalizing for the two different groups of

vehicles (LDV/LLDTs and HLDTs), we

are also finalizing the proposed

requirement that manufacturers

compute their corporate Tier 2 NOX

averages separately for LDV/LLDTs and

HLDTs through 2008. As we proposed,

credit exchanges between LDVs/LLDTs

and HLDTs will not be allowed nor will

credit exchanges across the interim

programs or between the interim

programs and the final Tier 2 program

be allowed. These restrictions will end

with the 2009 model year at which time

both phase-ins and all interim standards

will have ended and the program will

permit free averaging across all Tier 2

vehicles. As noted in the NPRM, we are

concerned that allowing cross-trading

between interim and Tier 2 vehicles will

reduce the expected benefits of the

program and delay fleet turnover to Tier

2 emission levels. For this reason we

did not propose and are not finalizing

to permit such exchanges.

ii. Averaging, Banking, and Trading of

NOX Credits Fulfills Several Goals

We explained in the NPRM why we

believe the provisions for averaging,

banking, and trading of NOX credits

(ABT) will be valuable. In short:

• An ABT program is an important

factor that EPA takes into consideration

in setting emission standards that are

appropriate under section 202 of the

Clean Air Act. ABT allows us to

consider a more stringent emission

standard than might otherwise be

appropriate under the CAA, since ABT

reduces the cost and improves the

technological feasibility of achieving the

standard;

• ABT enhances the technological

feasibility and cost effectiveness of the

proposed standard and allows the

standard to be attainable earlier than

might otherwise be possible;

• ABT provides manufacturers with

additional product planning flexibility

and the opportunity for a more cost

effective introduction of product lines;

• ABT creates incentive for early

introduction of new technology,

allowing certain engine families to act

as trail blazers for new technology;

We view the ABT provisions in

today’s rule as environmentally neutral

because the use of credits by some

vehicles is offset by credits generated by

other vehicles. However, when coupled

with the new standards, ABT will have

environmental benefits because it

allows the new standards to be

implemented earlier than would

otherwise be appropriate.

iii. How Manufacturers Can Generate

and Use NOX Credits

Manufacturers will determine their

year-end corporate average NOX

emission level by computing a salesweighted average of the NOX standard

from each bin to which the

manufacturer certifies any LDVs or

LDTs. Tier 2 NOX credits will be

generated when a manufacturer’s

average is below the 0.07 gram per mile

corporate average NOX standard,

according to this formula:

NOX Credits=(0.07 g/mi¥Corporate

Average NOX)×Sales

The manufacturer can use these NOX

credits in future years if its corporate

NOX average is above 0.07, or it can

trade (sell) the credits to other

manufacturers. Tier 2 credits can be

generated via this mechanism beginning

in the first phase-in year, i.e., 2004 for

LDV/LLDTs and 2008 for HLDTs. The

use of NOX credits will not be permitted

to address Selective Enforcement

Auditing or in-use testing failures.

The enforcement of the NOX

averaging standard will occur through

the vehicle’s certificate of conformity. A

manufacturer’s certificate of conformity

will be conditioned upon compliance

with the averaging provisions. The

certificate will be void ab initio if a

manufacturer fails to meet the corporate

average NOX standard and does not

obtain appropriate credits to cover its

shortfall in that model year or in the

next three model years (see deficit

carryforward provision below).

Manufacturers will need to track their

certification levels and sales unless they

produce only vehicles certified to bins

containing NOX levels of 0.07 g/mi or

below and do not plan to bank NOX

credits.

iv. Manufacturers Can Earn and Bank

Credits for Early NOX Reductions

In the NPRM, we proposed that to the

extent a manufacturer’s corporate

average NOX level of its ‘‘early Tier 2’’

vehicles was below 0.07 g/mi, the

manufacturer could bank NOX credits

for later use. We recognize (and the

comments assert) that this provision

may be lightly used, because it requires

a large reduction from prior standards to

produce any credits. However, our goal

is to bring vehicles to Tier 2 levels as

quickly as possible and we are

concerned that any other approach

could provide credits for reductions

manufacturers would make relatively

easily from previous, higher standards.

Such credits would then be used to

delay the impact of the 0.07 g/mi NOX

standard. Further, we believe that our

provision for alternative phase-in

schedules provides what is essentially a

supplemental, or perhaps even primary,

early banking program, in that it permits

manufacturers to trade-off earlier phasein percentages for later phase-in

percentages. To provide manufacturers

with greater flexibility and with

incentives to certify, produce and sell

Tier 2 vehicles as early as possible, we

are finalizing the alternative phase-in

provisions. (See IV.B.4.b.ii above.)

Under such schedules, a manufacturer

can certify vehicles to an average NOX

level of 0.07 g/mi or below in years

prior to the first required phase-in year

and then phase its remaining vehicles in

over a more gradual phase-in schedule

that will still lead to 100% compliance

by 2007 (2009 for HLDTs).

Thus, we are finalizing our provision

for early NOX credits essentially as

proposed. To the extent that a

manufacturer’s corporate average NOX

level of its ‘‘early Tier 2’’ vehicles is

below 0.07 g/mi, the manufacturer can

bank NOX credits for later use.

Manufacturers will compute these early

credits by calculating a sales-weighted

corporate average NOX emission level of

their Tier 2 vehicles, as in the basic Tier

2 program described above. In section

IV.B.4.d.vii. below, we describe

provisions we are adding to the final

rule that will enable manufacturers to

generate extra credits from vehicles

certified to very low levels. In addition

to encouraging production of very clean

vehicles, these provisions, which apply

beginning in 2001, will enhance the

abilities of manufacturers to generate

early credits.

Early Tier 2 credits will have all the

same properties as credits generated by

vehicles subject to the primary phase-in

schedule. We proposed that these

credits could not be used in the NLEV,

Tier 1 or interim program for non-Tier

2 vehicles in any way. We are finalizing

this restriction as proposed. We are also

finalizing as proposed that the NMOG

emissions of these vehicles (LDVs and

LLDTs only) can be used in the

Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations 6745

69Because of the limited duration of the interim

programs, we proposed that a manufacturer could

carry a credit deficit in the interim program forward

until the 2006 model year (2008 for HLDTs). The

interim program, in its entirety, lasts only five years

and therefore we saw little risk of prolonged

deficits.

calculation of the manufacturer’s

corporate average NMOG emissions

under NLEV through 2003.

To provide manufacturers with

maximum flexibility in the period prior

to 2004, when LDV/LLDT useful lives

will still be at 100,000 miles, we

proposed and are finalizing that

manufacturers may choose between the

Tier 2 120,000 mile useful life or the

current 100,000 mile useful life

requirement for early Tier 2 LDV/

LLDTs. (HLDTs already have a 120,000

mile useful life.) Early LDV/LLDT NOX

credits for 100,000 mile useful life

vehicles will have to be prorated by

100,000/120,000 (5/6) so that they can

be properly applied to 120,000 mile Tier

2 vehicles in 2004 or later.

We proposed to restrict early banking

of HLDT Tier 2 NOX credits to the four

year period from 2004–2007. This

restriction was due to a concern about

excessive credits generation if a longer

credit generation period was available.

Based on our review of the comments

and from reconsideration of the

restrictive nature of our approach for

early credits, we are much less

concerned that allowing generation of

early HLDT Tier 2 credits in years prior

to 2004 will result in excessive credits.

Prior to 2004, manufacturers will only

be required to meet the Tier 1 standards

which are much higher than the final

Tier 2 standards. Manufacturers will

have to make large cuts in emissions to

bank the small amount of credits offered

by our early banking provision. Further,

we recognize that vehicles that meet the

Tier 2 standards early provide an

environmental benefit, and the earlier

that benefit occurs, the earlier that areas

can use such benefits to reach or come

close to attainment. Lastly, we believe it

is appropriate to match the period of

early credit generation with the years in

which we will permit alternative phasein schedules. Consequently, we are

finalizing our provisions for early

banking such that manufacturers may

bank early Tier 2 NOX credits in model

years 2001–2007.

We recognize that vehicles generating

early Tier 2 NOX credits may be doing

so without the emissions benefit of low

sulfur fuel, and thus these vehicles may

not achieve the full in-use emission

reduction for which they received

credit. When these credits are used to

permit the sale of higher-emitting

vehicles, there may be a net increase in

emissions. For the most part, this is a

problem anyway, since NLEV vehicles

are also sensitive to gasoline sulfur. We

believe that the benefits of early

introduction of Tier 2 technology

described above are significant enough

that they are worth the risk of some

emission losses that might occur if and

when the early credits are used. Also,

we believe that some fuel sulfur

reductions will occur prior to 2004 as

refiners upgrade their refineries or bring

new refining capacity on stream in

anticipation of the 2004 requirements

and take advantage of the phase-in

proposed in the gasoline sulfur ABT

program (described in Section IV.C.

below).

v. Tier 2 NOX Credits Will Have

Unlimited Life

We discussed in the preamble to the

NPRM why we did not propose to apply

the California schedule of discounting

unused credits adopted for NMOG

credits in the NLEV program. This

schedule serves to limit credit life

throughout the program by reducing

unused credits to 50, 25 and 0 percent

of their original number at the end of

the second, third and fourth year,

respectively, following the year in

which they were generated. We agree

that such a scheme may be appropriate

in the California program with its

declining NMOG average standard, but

in the federal program, once the phasein period ends in model year 2009, all

LDVs and LDTs will comply on average

with a fixed Tier 2 NOX standard.

Credits allow manufacturers

flexibility to meet standards cost

effectively and to address unexpected

shifts in sales mix. When matched with

a NOX average standard, credits provide

flexibility constrained by the

requirement that all vehicles, on

average, must comply with a fixed

standard. Defined bins of standards

prevent any one vehicle from having

extremely high emissions, while the

need to offset higher vehicles with

lower vehicles to meet an average NOX

standard prevents large numbers of

vehicles from utilizing the higher bins.

We requested comment in the NPRM

on the need for discounting of credits or

limits on credit life and what those

discount rates or limits, if any, should

be. The 0.07 NOX emission standard in

the Tier 2 program is quite stringent and

does not present easy opportunities to

generate credits. The degree to which

manufacturers invest the resources to

achieve extra NOX reductions provides

environmental benefit for years to come

and it is appropriate that the

manufacturer get credits. We do not

want to take measures to reduce the

incentive for manufacturers to bank

credits nor do we want to take measures

to encourage unnecessary credit use.

Consequently we are finalizing our

proposal that Tier 2 NOX credits,

including early credits, have unlimited

lives.

vi. NOX Credit Deficits Can Be Carried

Forward

When a manufacturer has a NOX

deficit at the end of a model year—that

is, its corporate average NOX level is

above the required corporate average

NOX standard—we proposed that the

manufacturer could carry that deficit

forward into the next model year. Such

a carry-forward could only occur after

the manufacturer used any banked

credits. If the deficit still existed and the

manufacturer chose not to or was unable

to purchase credits, the deficit could be

carried over. At the end of that next

model year, according to our proposal,

the deficit would need to be covered

with an appropriate number of NOX

credits that the manufacturer generated

or purchased. Any remaining deficit

would be subject to an enforcement

action. To prevent deficits from being

carried forward indefinitely, the

manufacturer would not be permitted to

run a deficit for two years in a row.69

Manufacturers made the persuasive

case that by the time they can tabulate

their average NOX emissions for a

particular model year, the next model

year is likely well underway and it is

too late to make calibration, marketing

or sales mix changes to adjust that year’s

credit generation. Therefore, based upon

comments, we are finalizing a modified

approach to credit deficits such that a

manufacturer having a credit deficit in

the interim or Tier 2 program can carry

that deficit forward for a total of three

years, but the manufacturer must apply

all its available credits to that deficit on

a one-for-one basis in each of the first

two succeeding model years. If the

deficit is not covered by the third model

year, the manufacturer must apply

credits at a rate of 1.2:1. No deficit may

be carried into the fourth year. In order

to accommodate this modification to our

proposal, we must also modify our

proposed provision that would have

prevented manufacturers from running a

deficit in two consecutive model years

so that deficits can not be shifted from

one year to the next and thus carried

forward indefinitely. Because we are

permitting, in this final rule, deficits to

be carried forward for as long as three

years we are finalizing that

manufacturers can not run a deficit in

any year in which it is paying off a

deficit from a previous year. The effect

of this provision is the same as that in

6746 Federal Register / Vol. 65, No. 28 / Thursday, February 10, 2000 / Rules and Regulations

the NPRM— to keep manufacturers from

shifting deficits forward indefinitely.

We note that under our modified final

approach, manufacturers will have the

flexibility to carry deficits from the

interim program forward into the final

Tier 2 program. This feature is likely to

be used only in an extreme situation

since the Tier 2 credits needed to offset

the interim credit deficit will be more

difficult to generate. Consequently, we

do not believe this provision is

inconsistent with our approach of

segregating interim and Tier 2 credits. In

fact, manufacturers electing to cover an

interim credit deficit with Tier 2 credits

will likely have to accelerate the

introduction of Tier 2 vehicles to get the

necessary credits to cover the deficit.

We are finalizing that small volume

manufacturers may not use the credit

deficit carryforward provision until they

have been in compliance with the

relevant average NOX standard for one

model year. In section V of this

preamble we explain that we are not

requiring small volume manufacturers

to comply with intermediate phase-in

requirements under our interim or Tier

2 phase-ins. Rather, they will just have

to comply for all of their vehicles in the

last phase-in year. Because they do not

have to comply with intermediate

phase-in requirements, small volume

manufacturers effectively get more time

to comply (as much as three years). We

do not want to create a situation where

they could get even more time to

comply by using the credit deficit

carryforward provision.

vii. Encouraging the Introduction of

Ultra-Clean Vehicles

We requested comment in the NPRM

as to whether we should provide

additional NOX credits for vehicles that

certify to very low levels. We stated in

the NPRM that we believe it is

appropriate to provide inducements to

manufacturers to certify vehicles to very

low levels and that these inducements

may help pave the way for greater and/

or more cost effective emission

reductions from future vehicles. We

believe it is important in a rule of this

nature to provide extra incentive to

encourage manufacturers to produce

and market very clean vehicles. We

believe this is especially important in

the earliest years of the program when

manufacturers must make resource

commitments to technologies and

vehicle designs that will have multiyear life spans. We believe this program

provides a strong incentive for

manufacturers to maximize their

development and introduction of the

best available vehicle/engine emission

control technology, and this in turn

provides a stepping stone to the broader

introduction of this technology soon

thereafter. Early production of cleaner

vehicles enhances the early benefits of

our program and vehicles certified to

these lowest bins produce not just lower

NOX but also lower NMOG, CO and

HCHO emissions. If a manufacturer can

be induced to certify to a lower bin by

the promise of reasonable extra credits,

the benefits of that decision to the

program may last for many years.

We are finalizing provisions to permit

manufacturers, at the beginning of the

program, to weight LDV/Ts certified to

the lowest two bins more heavily when

calculating their fleet average NOX

emissions. Under this provision, which

applies through the 2005 model year,

manufacturers may apply a multiplier to

the number of LDV/Ts sold that are

certified to bins 1 and 2 (ZEVs and

SULEVs in California terms). This

adjusted number will be used in the

calculation of fleet average NOX

emissions for a given model year and

will allow manufacturers having

vehicles certified to these bins to

generate additional credits (or use fewer

credits) that year.

The multipliers that manufacturers

may use are found in Table IV.B.–8

below:

TABLE IV.B.–8.—MULTIPLIERS FOR ADDITIONAL CREDITS FOR BIN 1 AND 2 LDV/T

Bin Model year Multiplier

2 .................................................................................................. 2001, 2002, 2003, 2004, 2005 ................................................... 1.5

1 .................................................................................................. 2001, 2002, 2003, 2004, 2005 ................................................... 2.0

e. Interim Standards

i. Interim Exhaust Emission Standards

for LDV/LLDTs

The NLEV program referenced

throughout this discussion is a

voluntary program in which all major

manufacturers have opted to produce

LDVs and LLDTs to tighter standards

than those required by EPA’s Tier 1

regulations. Under the NLEV program,

manufacturers must meet an NMOG

average outside of California that is

equivalent to California’s current

intermediate-life LEV requirement—

0.075 g/mi for LDVs and LDT1s (0.10 g/

mi for LDT2s). NLEV requirements

apply only to LDVs and LLDTs, not to

HLDTs.

The NLEV program is effective

beginning in the northeastern states in

1999 and in the remaining states in

2001, except that the program does not

apply to vehicles sold in California or in

states that adopted California’s LEV

program. The program runs at least

through model year 2003 and can run

through model year 2005.

Under the Tier 2 phase-in we are

finalizing today, not all LDV/LLDTs

covered under NLEV will be subject to

Tier 2 standards in the 2004 to 2006

period. Without a program for full Tier

2 compliance in 2004 (i.e., because of

the phase-in), these vehicles could

revert to Tier 1 standards. The NLEV

program, moreover, is a voluntary

program that contains several provisions

that restrict EPA’s flexibility and that

could lead to a manufacturer or a

covered Northeastern state leaving the

program in or prior to 2004. To resolve

these concerns we are finalizing the

proposed interim program for all nonTier 2 LDV/LLDTs for the 2004–2006

model years. Our interim program will

replace the NLEV program, which will

terminate at the end of 2003. The

transition from NLEV to the interim

program should be smooth because the

interim program will employ several

bins derived from the NLEV standards

for LDVs, LDT1s and LDT2s. The

interim program will ensure that all

LDVs, LDT1s and LDT2s that are not

certified to Tier 2 levels during the

2004–2006 phase-in period remain at

levels at least as stringent, on average,

as NLEV levels. The interim program

will also bring the emission standards

for LDT2s more into line with those for

the LDVs and LDT1s by requiring that

they be averaged under the same NOX

standard rather than under separate

standards as is the case in the NLEV

program.

In the NPRM, we included separate

sets of bins for the interim program and

Tier 2 program. However, we indicated

that manufacturers could use either set

for interim vehicles. In today’s final rule

we have combined all bins into one

table for simplicity. We have also added

two new bins having NOX values of 0.03

g/mi and 0.10 g/mi.