Control of Emissions of Air Pollution From Nonroad Diesel Engines and Fuel
Federal RegisterMay 23, 2003
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Text
Part II
Environmental Protection Agency
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40 CFR Parts 69, 80, 89, et al.
Control of Emissions of Air Pollution From Nonroad Diesel Engines and
Fuel; Proposed Rule
Federal Register / Vol. 68, No. 100 / Friday, May 23, 2003 / Proposed
Rules
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 69, 80, 89, 1039, 1065, and 1068
[AMS-FRL-7485-8]
RIN 2060-AK27
Control of Emissions of Air Pollution From Nonroad Diesel Engines
and Fuel
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of proposed rulemaking.
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SUMMARY: Nonroad diesel engines contribute considerably to our nation's
air pollution. These engines, used primarily in construction,
agricultural, and industrial applications, are projected to continue to
contribute large amounts of particulate matter (PM), nitrogen oxides
(NOX), and sulfur oxides (SOX), all of which
contribute to serious public health problems in the United States.
These problems include premature mortality, aggravation of respiratory
and cardiovascular disease, aggravation of existing asthma, acute
respiratory symptoms, chronic bronchitis, and decreased lung function.
We believe that diesel exhaust is likely to be carcinogenic to humans
by inhalation.
Today EPA is proposing new emission standards for nonroad diesel
engines and sulfur reductions in nonroad diesel fuel that will
dramatically reduce emissions attributed to nonroad diesel engines.
This comprehensive national program will regulate nonroad diesel
engines and diesel fuel as a system. New engine standards will begin to
take effect in the 2008 model year. These standards are based on the
use of advanced exhaust emission control devices. We estimate PM
reductions of 95%, NOX reductions of 90%, and the virtual
elimination of sulfur oxides (SOX) from nonroad engines
meeting the new standards. Nonroad diesel fuel sulfur reductions of up
to 99% from existing levels will provide significant health benefits as
well as facilitate the introduction of high-efficiency catalytic
exhaust emission control devices as these devices are damaged by
sulfur. These fuel controls would begin in mid-2007. Today's nonroad
proposal is largely based on EPA's 2007 highway diesel program.
To better ensure the benefits of the standards are realized in-use
and throughout the useful life of these engines, we are also proposing
new test procedures, including not-to-exceed requirements, and related
certification requirements. The proposal also includes provisions to
facilitate the transition to the new engine and fuel standards and to
encourage the early introduction of clean technologies and clean
nonroad diesel fuel. We have also developed provisions for both the
proposed engine and fuel programs designed to address small business
considerations.
The requirements in this proposal would result in substantial
benefits to public health and welfare and the environment through
significant reductions in emissions of NOX and PM, as well
as nonmethane hydrocarbons (NMHC), carbon monoxide (CO), sulfur oxides
(SOX) and air toxics. We project that by 2030, this program
would reduce annual emissions of NOX, and PM by 827,000 and
127,000 tons, respectively. These emission reductions would prevent
9,600 premature deaths, over 8,300 hospitalizations, and almost a
million work days lost, and other quantifiable benefits every year. All
told the benefits of this rule would be approximately $81 billion
annually by 2030. Costs for both the engine and fuel requirements would
be many times less, at approximately $1.5 billion annually.
DATES: Comments: Send written comments on this proposal by August 20,
2003. See section IX for more information about written comments.
Hearings: We will hold public hearings on the following dates: June
10, 2003; June 12, 2003; and June 17, 2003. Each hearing will start at
9 a.m. local time. If you want to testify at a hearing, notify the
contact person listed below at least 10 days before the hearing. See
section IX for more information about public hearings.
ADDRESSES: Comments: Comments may be submitted by mail to: Air Docket,
Environmental Protection Agency, Mailcode: 6102T, 1200 Pennsylvania
Ave., NW., Washington, DC 20460, Attention Docket ID No. A-2001-28.
Comments may also be submitted electronically, by facsimile, or
through hand delivery/courier. Follow the detailed instructions as
provided in section IX of the SUPPLEMENTARY INFORMATION section.
Hearings: We will hold public hearings at the following three
locations:
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New York, New York, Park Central New York, June 10, 2003
870 Seventh Avenue at 56th Street, New York,
NY 10019, Telephone: (212) 247-8000, Fax:
(212) 541-8506.
Chicago, Illinois, Hyatt Regency O'Hare, 9300 June 12, 2003.
W. Bryn Mawr Avenue, Rosemont, IL 60018,
Telephone: (847) 696-1234, Fax: (847) 698-
0139.
Los Angeles. California, Hyatt Regency Los June 17, 2003.
Angeles, 711 South Hope Street, Los Angeles,
California, USA. 90017, Telephone: (213) 683-
1234, Fax: (213) 629-3230.
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See section IX, ``Public Participation'' below for more information
on the comment procedure and public hearings.
FOR FURTHER INFORMATION CONTACT: U.S. EPA, Office of Transportation and
Air Quality, Assessment and Standards Division hotline, (734) 214-4636,
[email protected]. Carol Connell, (734) 214-4349; [email protected].
SUPPLEMENTARY INFORMATION:
Regulated Entities
This action would affect you if you produce or import new heavy-
duty diesel engines which are intended for use in nonroad vehicles such
as agricultural and construction equipment, or produce or import such
nonroad vehicles, or convert heavy-duty vehicles or heavy-duty engines
used in nonroad vehicles to use alternative fuels. It would also affect
you if you produce, import, distribute, or sell nonroad diesel fuel, or
sell nonroad diesel fuel.
The following table gives some examples of entities that may have
to follow the regulations. But because these are only examples, you
should carefully examine the regulations in 40 CFR parts 80, 89, 1039,
1065, and 1068. If you have questions, call the person listed in the
FOR FURTHER INFORMATION CONTACT section of this preamble:
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NAICS SIC
Category codes codes Examples of potentially regulated entities
\a\ \b\
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Industry...................................... 333618 3519 Manufacturers of new nonroad diesel engines.
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Industry...................................... 333111 3523 Manufacturers of farm machinery and equipment.
Industry...................................... 333112 3524 Manufacturers of lawn and garden tractors (home).
Industry...................................... 333924 3537 Manufacturers of industrial trucks.
Industry...................................... 333120 3531 Manufacturers of construction machinery.
Industry...................................... 333131 3532 Manufacturers of mining machinery and equipment.
Industry...................................... 333132 3533 Manufacturers of oil and gas field machinery and equipment.
Industry...................................... 811112 7533 Commercial importers of vehicles and vehicle components.
811198 7549
Industry...................................... 324110 2911 Petroleum refiners.
Industry...................................... 422710 5171 Diesel fuel marketers and distributors.
422720 5172
Industry...................................... 484220 4212 Diesel fuel carriers.
484230 4213
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\a\ North American Industry Classification System (NAICS).
\b\ Standard Industrial Classification (SIC) system code.
How Can I Get Copies of This Document and Other Related Information?
Docket. EPA has established an official public docket for this
action under Docket ID No. A-2001-28. The official public docket
consists of the documents specifically referenced in this action, any
public comments received, and other information related to this action.
Although a part of the official docket, the public docket does not
include Confidential Business Information (CBI) or other information
whose disclosure is restricted by statute. The official public docket
is the collection of materials that is available for public viewing at
the Air Docket in the EPA Docket Center, (EPA/DC) EPA West, Room B102,
1301 Constitution Ave., NW., Washington, DC. The EPA Docket Center
Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The telephone number for the Reading
Room is (202) 566-1742, and the telephone number for the Air Docket is
(202) 566-1742.
Electronic Access. You may access this Federal Register document
electronically through the EPA Internet under the ``Federal Register''
listings at http://www.epa.gov/fedrgstr/.
An electronic version of the public docket is available through
EPA's electronic public docket and comment system, EPA Dockets. You may
use EPA Dockets at http://www.epa.gov/edocket/ to submit or view public
comments, access the index listing of the contents of the official
public docket, and to access those documents in the public docket that
are available electronically. Once in the system, select ``search,''
then key in the appropriate docket identification number.
Certain types of information will not be placed in the EPA Dockets.
Information claimed as CBI and other information whose disclosure is
restricted by statute, which is not included in the official public
docket, will not be available for public viewing in EPA's electronic
public docket. EPA's policy is that copyrighted material will not be
placed in EPA's electronic public docket but will be available only in
printed, paper form in the official public docket. To the extent
feasible, publicly available docket materials will be made available in
EPA's electronic public docket. When a document is selected from the
index list in EPA Dockets, the system will identify whether the
document is available for viewing in EPA's electronic public docket.
Although not all docket materials may be available electronically, you
may still access any of the publicly available docket materials through
the docket facility identified in section IX.
For public commenters, it is important to note that EPA's policy is
that public comments, whether submitted electronically or in paper,
will be made available for public viewing in EPA's electronic public
docket as EPA receives them and without change, unless the comment
contains copyrighted material, CBI, or other information whose
disclosure is restricted by statute. When EPA identifies a comment
containing copyrighted material, EPA will provide a reference to that
material in the version of the comment that is placed in EPA's
electronic public docket. The entire printed comment, including the
copyrighted material, will be available in the public docket.
Public comments submitted on computer disks that are mailed or
delivered to the docket will be transferred to EPA's electronic public
docket. Public comments that are mailed or delivered to the Docket will
be scanned and placed in EPA's electronic public docket. Where
practical, physical objects will be photographed, and the photograph
will be placed in EPA's electronic public docket along with a brief
description written by the docket staff.
For additional information about EPA's electronic public docket
visit EPA Dockets online or see 67 FR 38102, May 31, 2002.
Outline of This Preamble
I. Overview
A. What Is EPA Proposing?
1. Nonroad Diesel Engine Emission Standards
2. Nonroad, Locomotive, and Marine Diesel Fuel Quality Standards
B. Why Is EPA Making This Proposal?
1. Nonroad, Locomotive, and Marine Diesels Contribute to Serious
Air Pollution Problems
2. Technology and Fuel Based Solutions
3. Basis For Action Under the Clean Air Act
II. What Is the Air Quality Impact of the Sources Covered by the
Proposed Rule?
A. Overview
B. Public Health Impacts
1. Particulate Matter
a. Health Effects of PM2.5 and PM10
b. Current and Projected Levels
i. PM10 Levels
ii. PM2.5 Levels
2. Air Toxics
a. Diesel exhaust
i. Potential Cancer Effects of Diesel Exhaust
ii. Other Health Effects of Diesel Exhaust
iii. Ambient Levels and Exposure to Diesel Exhaust PM
iv. Diesel Exhaust PM Exposures
b. Gaseous Air Toxics
3. Ozone
a. What are the health effects of ozone pollution?
b. Current and projected 8-hour ozone levels
C. Other Environmental Effects
1. Visibility
a. Visibility is Impaired by Fine PM and Precursor Emissions
From Nonroad Engines Subject to this Proposed Rule
b. Visibility Impairment Where People Live, Work and Recreate
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c. Visibility Impairment in Mandatory Federal Class I Areas
2. Acid Deposition
3. Eutrophication and Nitrification
4. Polycyclic Organic Matter Deposition
5. Plant Damage from Ozone
D. Other Criteria Pollutants Affected by This NPRM
E. Emissions From Nonroad Diesel Engines
1. PM2.5
2. NOX
3. SO2
4. VOC and Air Toxics
III. Nonroad Engine Standards
A. Why are We Setting New Engine Standards?
1.The Clean Air Act and Air Quality
2. The Technology Opportunity for Nonroad Diesel Engines
B. What Engine Standards are We Proposing?
1. Exhaust Emissions Standards
a. Standards Timing
b. Phase-In of NOX and NMHC Standards
c. Rationale for Restructured Horsepower Categories
d. PM Standards for Smaller Engines
i. X and PM Emissions From
Mobile Source Diesel Engines
a. PM Control Technologies
b. NOX Control Technologies
2. Can These Technologies Be Applied to Nonroad Engines and
Equipment?
a. Nonroad Operating Conditions and Exhaust Temperatures
b. Nonroad Operating Conditions and Durability
3. Are the Standards Proposed for Engines of 75 hp or Higher
Feasible?
4.Are the Standards Proposed for Engines =25 hp and
X
standards
5. Are the Standards Proposed for Engines X
standards for engines X Catalysts and the Need for Low Sulfur
Fuel
a. Sulfur Poisoning (Sulfate Storage) on NOX
Adsorbers
b. Sulfate Particulate Production and Sulfur Impacts on
Effectiveness of NOX Control Technologies
G. Reassessment of Control Technology for Engines Less Than 75
hp in 2007
IV. Our Proposed Program for Controlling Nonroad, Locomotive and
Marine Diesel Fuel Sulfur
A. Proposed Nonroad, Locomotive and Marine Diesel Fuel Quality
Standards
1. What Fuel Is Covered by this Proposal?
2. Standards and Deadlines for Refiners, Importers, and Fuel
Distributors
a. The First Step to 500 ppm
b. The Second Step to 15 ppm
c. Other Standard Provisions
d. Cetane Index or Aromatics Standard
B. Program Design and Structure
1. Background
2. Proposed Fuel Program Design and Structure
a. Program Beginning June 1, 2007
i. Use of a Marker To Differentiate Heating Oil from NRLM
ii. Non-highway Distillate Baseline Cap
iii. Setting the Non-highway Distillate Baseline
iv. Diesel Sulfur Credit Banking, and Trading Provisions for
2007
b. 2010
i. A Marker To Differentiate Locomotive and Marine Diesel from
Nonroad Diesel
ii. Diesel Sulfur Credit Banking and Trading Provisions for 2010
c. 2014
3. Other Options Considered
a. Highway Baseline and a NRLM baseline for 2007
i. Highway Baseline
ii. Nonroad, Locomotive, and Marine Baseline
iii. Combined Impact of Highway and NRLM Baselines
b. Locomotive and Marine Baseline for 2010
c. Designate and Track Volumes in 2007
i. Replacement for the Non-highway Baseline Approach
ii. Designate and Track as a Refiners Option in Addition to the
Baseline Approach
C. Hardship Provisions for Qualifying Refiners
1. Hardship Provisions for Qualifying Small Refiners
a. Qualifying Small Refiners
i. Regulatory Flexibility for Small Refiners
ii. Rationale for Small Refiner Provisions
iii. Limited Impact of Small Refiner Options on Program
Emissions Benefits
b. How Do We Define Small Refiners for Purposes of the Hardship
Provisions?
c. What Options Are Available for Small Refiners?
i. Delays in Nonroad Fuel Sulfur Standards for Small Refiners
ii. Options to Encourage Earlier Compliance by Small Refiners
d. How Do Refiners Apply for Small Refiner Status?
2. General Hardship Provisions
a. Temporary Waivers From Non-highway Diesel Sulfur Requirements
in Extreme Unforeseen Circumstances
b. Temporary Waivers Based on Extreme Hardship Circumstances
D. Should Any Individual States or Territories Be Excluded From
This Rule?
1. Alaska
a. How Was Alaska Treated Under the Highway Diesel Standards?
b. What Nonroad Standards Do We Propose for Urban Areas of
Alaska?
c. What Do We Propose for Rural Areas of Alaska?
2. American Samoa, Guam, and the Commonwealth of Northern
Mariana Islands
a. What Provisions Apply in American Samoa, Guam, and the
Commonwealth of Northern Mariana Islands?
b. Why Are We Treating These Territories Uniquely?
E. How Are State Diesel Fuel Programs Affected by the Sulfur
Diesel Program?
F. Technological Feasibility of the 500 and 15 ppm Sulfur Diesel
Fuel Program
1. What Is the Nonroad, Locomotive and Marine Diesel Fuel Market
Today?
2. How Do Nonroad, Locomotive and Marine Diesel Fuel Differ From
Highway Diesel Fuel?
3. What Technology Would Refiners Use To Meet the Proposed 500
ppm Sulfur Cap?
4. Has Technology To Meet a 500 ppm Cap Been Commercially
Demonstrated?
5. Availability of Leadtime To Meet the 2007 500 ppm Sulfur Cap
6. What Technology Would Refiners Use To Meet the Proposed 15
ppm Sulfur Cap for Nonroad Diesel Fuel?
7. Has Technology To Meet a 15 ppm Cap Been Commercially
Demonstrated?
8. Availability of Leadtime To Meet the 2010 15 ppm Sulfur Cap
9. Feasibility of Distributing Nonroad, Locomotive and Marine
Diesel Fuels That Meet the Proposed Sulfur Standards
a. Limiting Sulfur Contamination
b. Potential Need for Additional Product Segregation
G. What Are the Potential Impacts of the 15 ppm Sulfur Diesel
Program on Lubricity and Other Fuel Properties?
1. What Is Lubricity and Why Might It Be a Concern?
2. A Voluntary Approach on Lubricity
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3. What Other Impact Would Today's Actions Have on the
Performance of Diesel and Other Fuels?
H. Refinery Air Permitting
V. Economic Impacts
A. Refining and Distribution Costs
1. Refining Costs
2. Cost of Lubricity Additives
3. Distribution Costs
4. How EPA's Projected Costs Compare to Other Available
Estimates
5. Supply of Nonroad, Locomotive and Marine Diesel Fuel
6. Fuel Prices
B. Cost Savings to the Existing Fleet From the Use of Low Sulfur
Fuel
C. Engine and Equipment Cost Impacts
1. Engine Cost Impacts
a. Engine Fixed Costs
i. Engine and Emission Control Device R&D
ii. Engine-Related Tooling Costs
iii. Engine Certification Costs
b. Engine Variable Costs
i. NOX Adsorber System Costs
ii. Catalyzed Diesel Particulate Filter (CDPF) Costs
iii. CDPF Regeneration System Costs
iv. Closed-Crankcase Ventilation System (CCV) Costs
v. Variable Costs for Engines Below 75 Horsepower and Above 750
Horsepower
c. Engine Operating Costs
2. Equipment Cost Impacts
a. Equipment Fixed Costs
b. Equipment Variable Costs
3. Overall Engine and Equipment Cost Impacts
D. Annual Costs and Cost Per Ton
1. Annual Costs for the 500 ppm Fuel Program
2. Cost Per Ton for the 500 ppm Fuel Program
3. Annual Costs for the Proposed Two-Step Fuel Program and
Engine Program
4. Cost per Ton of Emissions Reduced for the Total Program
5. Comparison With Other Means of Reducing Emissions
E. Do the Benefits Outweigh the Costs of the Standards?
1. What were the results of the benefit-cost analysis?
2. What was our overall approach to the benefit-cost analysis?
3. What are the significant limitations of the benefit-cost
analysis?
F. Economic Impact Analysis
1. What is an Economic Impact Analysis?
2. What is EPA's Economic Analysis Approach for This Proposal?
3. What Are the Results of This Analysis?
a. Expected Market Impacts
b. Expected Welfare Impacts
VI. Alternative Program Options
A. Summary of Alternatives
B. Introduction of 15 ppm Nonroad Diesel Sulfur Fuel in One Step
1. Description of the One-Step Alternative
2. Engine Emission Impacts
3. Fuel Impacts
4. Emission and Benefit Impacts
C. Applying 15 ppm Requirement to Locomotive and Marine Diesel
Fuel
D. Other Alternatives
VII. Requirements for Engine and Equipment Manufacturers
A. Averaging, Banking, and Trading
1. Are we proposing to keep the ABT program for nonroad diesel
engines?
2. What are the provisions of the proposed ABT program?
3. Should we expand the nonroad ABT program to include credits
from retrofit of nonroad engines?
a. What would be the environmental impact of allowing ABT
nonroad retrofit credits?
b. How would EPA ensure compliance with retrofit emissions
standards?
c. What is the legal authority for a nonroad ABT retrofit
program?
B. Transition Provisions for Equipment Manufacturers
1. Why are we proposing transition provisions for equipment
manufacturers?
2. What transition provisions are we proposing for equipment
manufacturers?
a. Percent-of-Production Allowance
b. Small-Volume Allowance
c. Hardship Relief Provision
d. Existing Inventory Allowance
3. What are the recordkeeping, notification, reporting, and
labeling requirements associated with the equipment manufacturer
transition provisions?
a. Recordkeeping Requirements for Engine and Equipment
Manufacturers
b. Notification Requirements for Equipment Manufacturers
c. Reporting Requirements for Engine and Equipment Manufacturers
d. Labeling Requirements for Engine and Equipment Manufacturers
4. What are the proposed requirements associated with use of
transition provisions for equipment produced by foreign
manufacturers?
C. Engine and Equipment Small Business Provisions (SBREFA)
1. Nonroad Diesel Small Engine Manufacturers
a. Lead Time Transition Provisions for Small Engine
Manufacturers
i. What the Panel Recommended
ii. What EPA Is Proposing
b. Hardship Provisions for Small Engine Manufacturers
i. What the Panel Recommended
ii. What EPA Is Proposing
c. Other Small Engine Manufacturer Issues
i. What the Panel Recommended
ii. What EPA Is Proposing
2. Nonroad Diesel Small Equipment Manufacturers
a. Transition Provisions for Small Equipment Manufacturers
i. What the Panel Recommended
ii. What EPA Is Proposing
b. Hardship Provisions for Small Equipment Manufacturers
i. What the Panel Recommended
ii. What EPA is Proposing
D. Phase-In Provisions
E. What Might Be Done To Encourage Innovative Technologies?
1. Incentive Program for Early or Very Low Emission Engines
2. Continuance of the Existing Blue Sky Program
F. Provisions for Other Test and Measurement Changes
1. Supplemental Transient Test
2. Cold Start Testing
3. Control of Smoke
4. Steady-State Testing
5. Maximum Test Speed
6. Improvements to the Test Procedures
G. Not-To-Exceed Requirements
H. Certification Fuel
I. Labeling and Notification Requirements
J. Temporary In-Use Compliance Margins
K. Defect Reporting
L. Rated Power
M. Hydrocarbon Measurement and Definition
N. Auxiliary Emission Control Devices and Defeat Devices
O. Other Issues
VIII. Nonroad Diesel Fuel Program: Compliance and Enforcement
Provisions
A. Fuel Covered and Not Covered by This Proposal
1. Covered Fuel
2. Special Fuel Provisions and Exemptions
a. Fuel Used in Military Applications
b. Fuel Used in Research and Development
c. Fuel Used in Racing Equipment
d. Fuel for Export
B. Additional Requirements for Refiners and Importers
1. Transfer of Credits
2. Additional Provisions for Importers and Foreign Refiners
Subject to the Credit Provisions or Hardship Provisions
3. Proposed Provisions for Transmix Facilities
4. Highway or Nonroad Diesel Fuel Treated as Blendstock (DTAB)
C. Requirements for Parties Downstream of the Refinery or Import
Facility
1. Product Segregation and Contamination
a. The Period From June 1, 2007 Through May 31, 2010
b. The Period From June 1, 2010 Through May 31, 2014
c. After May 31, 2014
2. Diesel Fuel Pump Labeling To Discourage Misfueling
a. Pump Labeling Requirements 2006
b. Pump Labeling Requirements 2007-2010
c. Pump Labeling Requirements 2010-2014
d. Pump Labeling Requirements Beginning June 1, 2014
e. Nozzle Size Requirements or Other Requirements To Prevent
Misfueling
3. Use of Used Motor Oil in New Nonroad Diesel Equipment
4. Use of Kerosene in Diesel Fuel
5. Use of Diesel Fuel Additives
6. End User Requirements
7. Anti-Downgrading Provisions
D. Diesel Fuel Sulfur Sampling and Testing Requirements
1. Testing Requirements
a. Test Method Approval, Recordkeeping, and Quality Control
Requirements
i. How Can a Given Method Be Approved?
ii. What Information Would Have To Be Reported to the Agency?
iii. What Quality Control Provisions Would Be Required?
b. Requirements To Conduct Fuel Sulfur Testing.
2. Two Part-Per-Million Downstream Sulfur Measurement Adjustment
3. Sampling Requirements
4. Alternative Sampling and Testing Requirements for Importers
of Diesel
[[Page 28332]]
Fuel Who Transport Diesel Fuel by Tanker Truck
E. Fuel Marker Test Method
1. How Can a Given Marker Test Method Be Approved?
2. What Information Would Have To Be Reported to the Agency?
F. Requirements for Recordkeeping, Reporting, and Product
Transfer Documents
1. Registration of Refiners and Importers
2. Application for Small Refiner Status
3. Applying for Refiner Hardship Relief
4. Applying for a Non-Highway Distillate Baseline Percentage
5. Pre-Compliance Reports
6. Annual Compliance Reports and Batch Reports for Refiners and
Importers
7. Product Transfer Documents (PTDs)
a. The Period From June 1, 2007 Through May 31, 2010
b. The Period from June 1, 2010 Through May 31, 2014
c. The Period After May 31, 2014
d. Kerosene and Other Distillates To Reduce Viscosity
e. Exported Fuel
f. Additives
8. Recordkeeping Requirements
9. Record Retention
G. Liability and Penalty Provisions for Noncompliance
1. General
2. What Are the Proposed Liability Provisions for Additive
Manufacturers and Distributors, and Parties That Blend Additives
Into Diesel Fuel?
a. General
b. Liability When the Additive Is Designated as Complying With
the 15 ppm Sulfur Standard
c. Liability When the Additive Is Designated as Having a
Possible Sulfur Content Greater Than 15 ppm
H. How Would Compliance With the Sulfur Standards Be Determined?
IX. Public Participation
A. How and to Whom Do I Submit Comments?
1. Electronically
i. EPA Dockets
ii. E-mail
iii. Disk or CD ROM
2. By Mail
3. By Hand Delivery or Courier
B. How Should I Submit CBI to the Agency?
C. Will There Be a Public Hearing?
D. Comment Period
E. What Should I Consider as I Prepare My Comments for EPA?
X. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review
B. Paperwork Reduction Act
C. Regulatory Flexibility Act (RFA), as Amended by the Small
Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5
U.S.C. 601 et. seq
1. Overview
2. Background
3. Summary of Regulated Small Entities
a. Nonroad Diesel Engine Manufacturers
b. Nonroad Diesel Equipment Manufacturers
c. Nonroad Diesel Fuel Refiners
d. Nonroad Diesel Fuel Distributors and Marketers
4. Potential Reporting, Record Keeping, and Compliance
5. Relevant Federal Rules
6. Summary of SBREFA Panel Process and Panel Outreach
a. Significant Panel Findings
b. Panel Process
c. Transition Flexibilities
i. Nonroad Diesel Engines
ii. Nonroad Diesel Equipment
iii. Nonroad Diesel Fuel Refiners
iv. Nonroad Diesel Fuel Distributors and Marketers
D. Unfunded Mandates Reform Act
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
G. Executive Order 13045: Protection of Children From
Environmental Health and Safety Risks
H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
I. National Technology Transfer Advancement Act
J. Plain Language
XI. Statutory Provisions and Legal Authority
I. Overview
Nonroad diesel engines are the largest remaining contributor to the
overall mobile source emissions inventory. We have already taken steps
to dramatically reduce emissions from light-duty vehicles and heavy-
duty vehicles and engines through the Tier 2 and 2007 highway diesel
programs.\1\ With expected growth in the nonroad sector, the relative
emissions contribution from nonroad diesel engines is projected to be
even larger in future years. This proposed rule sets out emissions
standards for nonroad diesel engines used mainly in construction,
agricultural, industrial, and mining operations that will achieve
reductions in PM and NOX emissions levels from today's
engines in excess of 95% and 90%, respectively. Nonroad diesel fuel is
currently unregulated. This proposal represents the first time nonroad
diesel fuel will be regulated. We are proposing to reduce sulfur levels
in nonroad diesel fuel by more than 99 percent to 15 parts per million
(ppm). Taken together, controls included in this proposal would result
in large public health and welfare benefits.
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\1\ See 65 FR 6698 (February 10, 2000) and 66 FR 5001 (January
18, 2001) for the final rules regarding the Tier 2 and 2007 highway
diesel programs, respectively.
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The proposed standards for nonroad diesel engines and sulfur
reductions for nonroad diesel fuel represent a dramatic step in
emissions control, based on the use of advanced emissions control
technology. Until the mid-90's, these engines had no emissions
requirements. As a comparison, cars and trucks have been subject to a
series of increasingly stringent emissions control programs since the
1970s. In terms of fuel quality requirements, nonroad diesel fuel is
currently uncontrolled at the Federal level. EPA has already issued
rules ending these disparities for diesel engines used in highway
applications. Starting in 2007, these engines will meet standards of
the same level of stringency as comparable gasoline vehicles, based on
the use of advanced aftertreatment technologies and ultra low sulfur
diesel fuel (containing no more than 15 ppm sulfur). This proposal is
largely based on the performance of the same advanced aftertreatment
technologies, and would bring nonroad diesel fuel to the same 15 ppm
cap for sulfur that will be required for highway diesel fuel starting
in 2006. We believe it is highly appropriate to propose dramatic steps
forward in emissions standards and reductions in sulfur levels in
nonroad diesel fuel. As discussed throughout this proposal, such steps
represent a feasible progression in the application of advanced
emissions control technologies, would achieve needed production of low
sulfur diesel fuel to enable the advanced emission control
technologies, the standards are cost-effective, and provide very large
public health and welfare benefits.
We followed certain principles when developing the elements of this
proposal. First, the program must achieve reductions in NOX,
SOx, and PM emissions as early as possible. This includes reductions
from the in-use fleet of nonroad diesel engines. Second, as we did in
the 2007 highway diesel program, we are treating vehicles and fuels as
a system since we believe this is the best way to achieve the greatest
emissions reductions. Third, the implementation of low sulfur
requirements for nonroad diesel fuel must in no way interfere with the
implementation and expected benefits of introducing ultra low sulfur
fuel in the highway market, as required by the 2007 highway diesel
program. Lastly, the program must provide sufficient lead time to allow
the integration of advanced emissions control technologies from the
highway sector onto nonroad diesel engines as well as the expansion of
ultra low sulfur fuel production to the nonroad market.
This proposal sets out new engine exhaust emissions standards,
emissions test procedures, including not-to-exceed requirements, for
nonroad engines, and sulfur control requirements for nonroad,
locomotive, and marine diesel fuel. The proposed exhaust standards
would
[[Page 28333]]
result in particulate matter (PM) and nitrogen oxide (NOX)
emissions levels that are in excess of 95 percent and 90 percent,
respectively, below comparable levels in effect today. They will begin
to take effect in the 2008 model year, with a phase-in of standards
across five different engine power rating groupings. New engine
emissions test procedures are proposed to take effect with these new
standards to better ensure emissions control over real-world engine
operation and to help provide for effective compliance determination.
Diesel fuel used in nonroad, locomotive, and marine applications would
meet a 500 ppm cap starting in June 2007, a reduction of approximately
90%. There are large benefits to taking this first sulfur reduction
action, especially in the reduction of particulate matter from the in-
use fleet. In 2010, sulfur levels in nonroad diesel fuel (though not
locomotive or marine diesel fuel) would meet a 15 ppm cap, for a total
reduction of over 99%. While there are important health and welfare
benefits associated with the reduction from 500 ppm to 15 ppm, the main
benefit will be to facilitate the introduction of advanced
aftertreatment devices on nonroad engines, which would in turn lead to
significant benefits. We are also seeking comment on and seriously
considering applying the 15 ppm cap to locomotive and marine diesel
fuel.
The requirements in this proposal would result in substantial
benefits to public health and welfare and the environment through
significant reductions in emissions of NOX and PM, as well
as nonmethane hydrocarbons (NMHC), carbon monoxide (CO), sulfur oxides
(SOX) and air toxics. We project that by 2030, this program
would reduce annual emissions of NOX, and PM by 827,000, and
127,000 tons, respectively. These annual emission reductions would
prevent 9,600 premature deaths, over 8,300 hospitalizations, and almost
a million work days lost, among quantifiable benefits. The overall
quantifiable benefits of this rule would be approximately $81 billion
annually by 2030. Costs for both the engine and fuel requirements would
be significantly less, at approximately $1.5 billion annually.
A. What Is EPA Proposing?
This proposal is a further step in EPA's long-term program to
control emissions from nonroad diesel engines. The EPA has taken
measures to reduce harmful emissions from nonroad diesel engines in two
past regulatory actions. A 1994 final rule, developed under provisions
of section 213 of the Clean Air Act, set initial emissions standards
for new nonroad diesel engines greater than 50 hp (59 FR 31306, June
17, 1994). These standards gained modest reductions in NOX
emissions and are referred to as EPA's ``Tier 1'' standards for large
nonroad engines. A subsequent final rule published in 1998 set more
stringent Tier 2 and Tier 3 standards for these engines, as well as
Tier 1 and Tier 2 standards for the nonroad diesel engines under 50 hp
(63 FR 56968, October 23, 1998). Nonroad diesel fuel quality is not
presently regulated by the EPA.
We also expressed our intent in the 1998 final rule to continue
evaluating the rapidly changing state of diesel emissions control
technology, and to perform a review in the 2001 timeframe of the
technological feasibility of the Tier 3 standards, and of the Tier 2
standards for engines rated under 50 hp. This review was completed in
2001 and documented in an EPA staff technical paper that confirmed the
feasibility of those standards, finding that the number of potential
control options had expanded since the 1998 final rule to include new
technologies and more effective application of existing
technologies.\2\
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\2\ ``Nonroad Diesel Emissions Standards Staff Technical
Paper'', EPA420-R-01-052, October 2001.
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There are two basic parts to this proposed program: (1) New exhaust
emission standards and test procedures for nonroad diesel engines, and
(2) new sulfur limits for nonroad, locomotive, and marine diesel fuel.
The systems approach of combining the engine and fuel standards into a
single program is critical to the success of our overall efforts to
reduce emissions, because the emission standards will not be feasible
without the fuel change. This proposal is largely based on the 2007
highway diesel program.
We looked at a number of alternative program options, as discussed
in more detail in section VI below and chapter 12 of the draft
Regulatory Impact Analysis (RIA). For example, we analyzed a program
that would require refiners to produce 15 ppm nonroad diesel fuel
starting in 2008, with appropriate engine standards phased-in beginning
in 2009. Many of these alternatives provided a very similar level of
projected emissions control and health and welfare benefits as our
proposed program. However, taking into account the need for appropriate
lead time, achieving the greatest possible emissions reductions as
early as possible, and the interaction of requirements in this proposal
with existing highway diesel engine environmental programs, we believe
our proposed program provides the best opportunity for achieving all of
our goals, as described above, including timely and significant
emissions reductions from nonroad diesel engines and the associated
introduction of ultra low sulfur nonroad diesel fuel. We are asking for
comments on the alternatives discussed in this proposal.
The elements of the rule are outlined below. Detailed provisions
and justifications for our proposed rule are discussed in subsequent
sections and the draft RIA.
1. Nonroad Diesel Engine Emission Standards
Today's action proposes standards for nonroad diesel engines
ranging from 3 to over 3,000 horsepower. Applicable emissions standards
are determined by year for each of five engine power band categories.
For engines less than 25 hp, we are proposing new engine standards for
PM (0.30 g/bhp-hr) and CO (4.9 g/bhp-hr) to go along with existing
NOX standards beginning in 2008. For engines between 25-75
hp, we are proposing standards reflecting approximately 50% reduction
in PM control from today's engines applicable in 2008. Then, starting
in 2013, PM standards of 0.02 g/bhp-hr and NOX standards of
3.5 g/bhp-hr would apply. For engines between 75-175 hp, the proposed
standards would be 0.01 g/bhp-hr for PM, 0.30 g/bhp-hr for
NOX, and 0.14 g/bhp-hr for HC beginning in 2012. These same
standards would apply for both engines between 175-750 hp and greater
than 750 hp starting in 2011. These PM, NOX, and NMHC
standards are similar in stringency to the final standards included in
the 2007 highway diesel program and are expected to require the use of
high-efficiency aftertreatment systems to ensure compliance. Thus,
virtually all nonroad diesel engines after 2013 would likely be using
advanced aftertreatment systems. We are phasing in many of these
proposed standards over a period of three years in order to address
lead time, workload, and feasibility considerations.
We are also proposing to continue the averaging, banking, and
trading nonroad emissions credits provisions to demonstrate compliance
with the standards. In addition, we are proposing to include
turbocharged diesels in the existing prohibition on crankcase
emissions, effective in the same year that the proposed Tier 4
standards first apply in each power category. More specific information
on the proposed standards can be found in section III below.
[[Page 28334]]
To better ensure the benefits of the standards are realized in-use
and throughout the useful life of these engines, we are also proposing
new test procedures and related certification requirements. We believe
the new supplemental transient test, Constant Speed Variable Load
transient duty cycle, cold start transient test, and not-to-exceed test
procedures and standards will all help achieve our goal. This is a
significant and important aspect of this proposal that would bring
greater confidence and certainty to the compliance program.
The proposal also includes provisions to facilitate the transition
to the new engine and fuel standards and to encourage the early
introduction of clean technologies. We are also including proposed
adjustments to various fuel and engine testing and compliance
requirements. These provisions are described further in sections III,
IV, and VI.
2. Nonroad, Locomotive, and Marine Diesel Fuel Quality Standards
We are proposing that sulfur levels for nonroad diesel fuel be
reduced from current uncontrolled levels ultimately to 15 ppm, though
we are proposing an interim cap of 500 ppm. Beginning June 1, 2007,
refiners would therefore be required to produce nonroad, locomotive,
and marine diesel fuel that meets a maximum sulfur level of 500 ppm.
This does not include diesel fuel for home heating, industrial boiler,
or stationary power uses or diesel fuel used in aircraft. We estimate
there are significant health and welfare benefits associated with this
proposed reduction, including reductions in sulfate emissions and
reduced engine operating expenses. Then, beginning in June 1, 2010,
fuel used for nonroad diesel applications (excluding locomotive and
marine engines) is proposed to meet a maximum sulfur level of 15 ppm,
since all 2011 and later model year nonroad diesel-fueled engines with
aftertreatment must be refueled with this new ultra low sulfur diesel
fuel. This sulfur standard is based on our assessment of the impact of
sulfur on advanced exhaust emission control technologies and a
corresponding assessment of the feasibility of ultra low sulfur fuel
production and distribution. We are also asking for comment on bringing
sulfur levels for locomotive and marine fuel to 15 ppm in 2010 and note
that we anticipate beginning the process of developing new engine
controls for these two sources in 2004. This proposal includes a
combination of provisions available to refiners, especially small
refiners, to ensure a smooth transition to ultra low sulfur nonroad
diesel fuel.
In addition, this proposal includes unique provisions for
implementing the ultra low sulfur diesel fuel program in the State of
Alaska. We are also proposing that certain U.S. territories be excluded
from both the nonroad engine standards and diesel fuel standards.
Similar actions were taken as part of the 2007 highway diesel program.
The compliance provisions for ensuring diesel fuel quality are
essentially consistent with those that have been in effect since 1993
for highway diesel fuel, reflecting updated requirements that were
included in the 2007 highway diesel program. Additional compliance
provisions are proposed for the transition years of the program
concerning the interaction of the nonroad, locomotive, and marine
sulfur control requirements with existing highway diesel sulfur control
provisions. These provisions could also help discourage misfueling of
nonroad equipment utilizing high-efficiency aftertreatment devices. The
proposed compliance requirements include provisions that would prohibit
equipment operators from fueling their machines with higher sulfur
fuels after completion of the shift to lower sulfur nonroad diesel
fuels, regardless of the age of their equipment.
B. Why Is EPA Making This Proposal?
1. Nonroad, Locomotive, and Marine Diesels Contribute to Serious Air
Pollution Problems
As discussed in detail in section II and chapter 2 and 3 of draft
RIA, emissions from nonroad, locomotive, and marine diesel engines
contribute greatly to a number of serious air pollution problems, and
these emissions would have continued to do so into the future absent
further controls to reduce them. First, these engines contribute to the
health and welfare effects associated with ozone, PM, NOX,
SOX, and volatile organic compounds (VOCs), including toxic
compounds such as formaldehyde. These adverse effects 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 structures, altered respiratory defense mechanisms, chronic
bronchitis, and decreased lung function.3 4 5 Second and
importantly, in addition to its contribution to ambient PM inventories,
diesel exhaust is of specific concern because it has been judged to
likely pose a lung cancer hazard for humans as well as a hazard from
noncancer respiratory effects. The Agency has classified diesel exhaust
as likely to be carcinogenic to humans by inhalation at environmental
exposures. Third, ozone and PM cause significant public welfare harm.
Specifically, ozone causes damage to vegetation which leads to economic
crop and forestry losses, as well as harm to national parks, wilderness
areas, and other natural systems. PM causes damage to materials and
soiling of commonly used building materials and culturally important
items such as statues and works of art. Fourth, NOX,
SOX and direct emissions of PM contribute to substantial
visibility impairment in many parts of the U.S. where people live,
work, and recreate, including mandatory Federal Class I areas. Finally,
NOX emissions from nonroad diesel engines contribute to the
acidification, nitrification and eutrophication of water bodies.
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\3\ U.S. EPA (1996) Air Quality Criteria for Particulate
Matter--Volumes I, II, and III, EPA Office of Research and
Development, National Center for Environmental Assessment, July
1996. Report No. EPA/600/P-95/001aF, EPA/600/P-95/001bF, EPA/600/P-
95/001cF.
\4\ U.S. EPA (2002), Air Quality Criteria for Particulate
Matter--Volumes I and II (Third External Review Draft). This
material is available electronically at http://cfpub.epa.gov/ncea/
cfm/partmatt.cfm.
\5\ U.S. EPA (1996) Air Quality Criteria for Ozone and Related
Photochemical Oxidants. EPA Office of Research and Development,
National Center for Environmental Assessment, July 1996. Report No.
EPA/600/P-93/004aF. The document is available on the Internet at
http://www.epa.gov/ncea/ozone.htm.
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Millions of Americans live in areas with unhealthful air quality
that may endanger public health and welfare (i.e., levels not requisite
to protect the public health with an adequate margin of safety). Based
upon data for 1999-2001, there are 291 counties that are violating the
8-hour ozone NAAQS, totaling 111 million people. In addition, at least
65 million people in 129 counties live in areas where annual design
values of ambient PM2.5 violate the PM2.5 NAAQS.
There are an additional 9 million people in 20 counties where levels
above the PM2.5 NAAQS are being measured, but the data are
incomplete. Without emission reductions from the proposed new standards
for nonroad engines, there is a significant future risk that 32
counties with 47 million people across the country may violate the 8-
hour ozone national ambient air quality standard (NAAQS) in 2030, based
on our modeling. Similarly, modeled PM2.5 concentrations in
107 counties where 85 million people live are above specified levels in
2030. An additional 64 million people are projected to live in counties
[[Page 28335]]
within 10 percent of the PM2.5 standard in 2030, and 44
million people are projected to live in counties within 10 percent of
the level of the 8-hour standard in 2030. Thus, our analyses show that
these counties face a significant risk of exceeding or failing to
maintain the PM2.5 and the 8-hour ozone NAAQS without
significant additional controls between 2007 and 2030.
Federal, State and local governments are working to bring ozone and
particulate levels into compliance with the NAAQS through State
Implementation Plan (SIP) attainment and maintenance plans, and to
ensure that future air quality reaches and continues to achieve these
health- and welfare-based standards. The reductions in this proposed
rulemaking will play a critical part in these important efforts to
attain and maintain the NAAQS. In addition, reductions from this action
will also reduce public health and welfare effects associated with
maintenance of the 1-hour ozone and PM10 NAAQS.
Emissions from nonroad, locomotive, and marine diesel engines
account for substantial portions of the country's ambient PM and
NOX levels. NOX is a key precursor to ozone and
PM formation. We estimate that these engines account for about ten
percent of total NOX emissions and about ten percent of
total PM emissions. These proportions are even higher in some urban
areas, where these engines contribute up to 19 percent of the total
NOX emissions and up to 18 percent of the total PM emissions
inventory. Over time, the relative contribution of these diesel engines
to air quality problems will go even higher unless EPA takes action to
further reduce pollution levels. For example, EPA has already taken
steps to bring emissions levels from light-duty and heavy-duty vehicles
and engines to near-zero levels by the end of this decade. The PM and
NOX standards for nonroad, locomotive, and marine diesel
engines in this proposal would have a substantial impact on emissions.
By 2030, NOX emissions from these diesel engines under
today's standards will be reduced by 827,000 tons, and PM emissions
will decline by about 127,000 tons, dramatically reducing this source
of NOX and PM emissions. Urban areas, which include many
poorer neighborhoods, can be disproportionately impacted by such diesel
emissions, and these neighborhoods will thus receive a relatively
larger portion of the benefits expected from proposed emissions
controls. Diesel exhaust is of special concern because it is associated
with increased risk of lung cancer and respiratory disease. EPA
recently issued its Health Assessment Document for Diesel Exhaust.\6\
The Agency has classified diesel exhaust as likely to be carcinogenic
to humans by inhalation at environmental exposures. State and local
governments, in their efforts to protect the health of their citizens
and comply with requirements of the Clean Air Act (CAA or ``the Act''),
have recognized the need to achieve major reductions in diesel PM
emissions, and have been seeking Agency action in setting stringent new
standards to bring this about.\7\
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\6\ U.S. EPA (2002) Health Assessment Document for Diesel Engine
Exhaust. EPA/600/8-90/057F Office of Research and Development,
Washington DC. This document is available electronically at http://
cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060.
\7\ For example, see letters dated April 9, 2002, from Agency
Secretary of California EPA, Commissioner of NY State DEC, and
Commissioner of Texas NRCC to Governor Whitman; dated January 28,
2003 from Western Regional Air Partnership to Governor Whitman, and
dated December 17, 2002, from State and Territorial Air Pollution
Program Administrators and Association of Local Air Pollution
Control Officials and Northeast States for Coordinated Air Use
Mangement (and other organizations).
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2. Technology and Fuel Based Solutions
Although the air pollution from nonroad diesel exhaust is
challenging, we believe they can be addressed through the application
of high-efficiency emissions control technologies. As discussed in much
greater detail in section III, the development of diesel emissions
control technology has advanced in recent years so that very large
emission reductions (in excess of 90 percent) are possible, especially
through the use of catalytic emission control devices installed in the
nonroad equipment's exhaust system and integrated with the engine
controls. These devices are often referred to as ``exhaust emission
control'' or ``aftertreatment'' devices. Exhaust emission control
devices, in the form of the well-known catalytic converter, have been
used in gasoline-fueled automobiles for 28 years.
Based on the Clean Air Act requirements in section 213, we are
proposing stringent new emission standards that will result in the use
of these diesel exhaust emission control devices. We are also proposing
changes to nonroad diesel fuel quality standards, under section 211(c)
of the Act, in order to enable these high-efficiency technologies.
To meet the proposed new standards, application of high-efficiency
exhaust emission controls for both PM and NOX will be needed
for most engines. High-efficiency PM exhaust emission control
technology has been available for several years. This technology has
continued to improve over the years, especially with respect to
durability and robust operation in use. It has also proved extremely
effective in reducing exhaust hydrocarbon emissions. Thousands of such
systems are now in use, especially in Europe. It is the same technology
we expect to be applied to meet the PM standards in the 2007 heavy-duty
highway diesel engine rule. However, as discussed in detail in section
III, these systems are very sensitive to sulfur in the fuel. For the
technology to be viable and capable of meeting the standards, we
believe it will require diesel fuel with sulfur content capped at the
15 ppm level.
Similarly, high-efficiency NOX exhaust emission control
technology will be needed if nonroad diesel engines are to attain the
proposed standards. This is the same technology that we anticipate will
be applied to heavy-duty highway diesel engines to meet the
NOX standards included in the 2007 highway diesel program.
This technology, like the PM technology, is dependant on the 15 ppm
maximum nonroad diesel fuel levels being proposed in this action in
order to be feasible and capable of achieving the standards. Similar
high-efficiency NOX exhaust emission control technology has
been quite successful in gasoline direct injection engines that operate
with an exhaust composition fairly similar to diesel exhaust and is
expected to be used to meet the 2007 and later heavy-duty highway
diesel standards. As discussed in section III, application of this
technology to nonroad diesels has some additional engineering
challenges. In that section, we discuss the current status of this
technology as well as the major development issues still to be
addressed and the development steps that can be taken. With the lead-
time available and the introduction of ultra low sulfur nonroad diesel
fuel, we are confident the proposed application of this technology to
nonroad diesels would proceed at a reasonable rate of progress and will
result in systems capable of achieving the standards.
This view is further supported by the fact that manufacturers are
already working on developing high-efficiency aftertreatment devices in
order to have them available for introduction on highway diesel engines
by 2007. EPA issued a progress report in June 2002 which discussed our
findings that industry was making substantial progress in developing
these devices. Additionally, the Clean Diesel Independent Review Panel
issued a report in October 2002 on similar
[[Page 28336]]
questions and concluded that, while technical issues remain, there were
no technical hurdles identified that would prevent market introduction
of high-efficiency aftertreatment devices on schedule.
The need to reduce sulfur in nonroad diesel fuel is driven by the
requirements of the exhaust emission control technology that we project
will be needed to meet the proposed standards for most nonroad diesel
engines. The challenge in accomplishing the sulfur reduction is driven
by the capacity to implement the needed refinery modifications, and by
the costs of making the modifications and running the equipment. Today,
a number of refiners are acting to provide low sulfur diesel to some
markets. We believe that controlling the sulfur content of highway
diesel fuel to the 15 ppm level is necessary, feasible, and cost-
effective.
Additionally, there are health and welfare benefits associated with
the initial step of reducing the sulfur level of nonroad, locomotive,
and marine diesel fuel to 500 ppm. This proposed action will provide
dramatic, immediate reductions in direct sulfate PM and SO2
emissions from the in-use fleet. As described in this proposal, we
believe this fuel control strategy is a cost-effective air quality
solution as well.
3. Basis for Action Under the Clean Air Act
Section 213 of the Act gives us the authority to establish
emissions standards for nonroad engines and vehicles. Section 213(a)(3)
authorizes the Administrator to set standards for NOX, VOCs,
or carbon monoxide, to reduce ambient levels of ozone and carbon
monoxide which ``standards shall achieve the greatest degree of
emission reduction achievable through the application of technology
which the Administrator determines will be available for the engines or
vehicles.'' As part of this determination, the Administrator must give
appropriate consideration to cost, lead time, noise, energy, and safety
factors associated with the application of such technology. Section
213(a)(4) authorizes the Administrator to establish standards to
control emissions of pollutants which ``may reasonably be anticipated
to endanger public health and welfare''. Here, the Administrator may
promulgate regulations that are deemed appropriate for new nonroad
vehicles and engines which cause or contribute to such air pollution,
taking into account costs, noise, safety, and energy factors. EPA
believes the proposed controls for PM in today's rule would be an
appropriate exercise of EPA's discretion under the authority of section
213(a)(4).
We believe the evidence provided in section III and the Draft
Regulatory Impact Analysis (RIA) indicates that the stringent emission
standards proposed today are feasible and reflect the greatest degree
of emission reduction achievable in the model years to which they
apply. We have given appropriate consideration to costs in proposing
these standards. Our review of the costs and cost-effectiveness of
these standards indicate that they will be reasonable and comparable to
the cost-effectiveness of other emission reduction strategies that have
been required or could be required in the future. We have also reviewed
and given appropriate consideration to the energy factors of this rule
in terms of fuel efficiency and effects on diesel fuel supply,
production, and distribution, as discussed below, as well as any safety
factors associated with these proposed standards.
The information in section II and chapter 2 of the draft RIA
regarding air quality and the contribution of nonroad, locomotive, and
marine diesel engines to air pollution provides strong evidence that
emissions from such engines significantly and adversely impact public
health or welfare. First, as noted earlier, there is a significant risk
that several areas will fail to attain or maintain compliance with the
NAAQS for 8-hour ozone concentrations or for PM2.5 concentrations
during the period that these new vehicle and engine standards will be
phased into the vehicle population, and that nonroad, locomotive, and
marine diesel engines contribute to such concentrations, as well as to
concentrations of other NAAQS-related pollutants. This risk will be
significantly reduced by the standards adopted today, as also noted
above. However, the evidence indicates that some risk remains even
after the reductions achieved by these new controls on nonroad diesel
engines and nonroad, locomotive, and marine diesel fuel. Second, EPA
believes that diesel exhaust is likely to be carcinogenic to humans.
The risk associated with exposure to diesel exhaust includes the
particulate and gaseous components among which are benzene,
formaldehyde, acetaldehyde, acrolein, and 1,3-butadiene, all of which
are known or suspected human or animal carcinogens, or have serious
noncancer health effects. Third, emissions from nonroad diesel engines
(including locomotive and marine diesel engines) contribute to regional
haze and impaired visibility across the nation, as well as acid
deposition, POM deposition, eutrophication and nitrification, all of
which are serious environmental welfare problems.
EPA has already found in previous rules that emissions from new
nonroad diesel engines contribute to ozone and carbon monoxide (CO)
concentrations in more than one area which has failed to attain the
ozone and carbon monoxide NAAQS. 59 FR 31306 (June 17, 1994). EPA has
also previously determined that it is appropriate to establish
standards for PM from new nonroad diesel engines under section
213(a)(4), and the additional information on diesel exhaust
carcinogenicity noted above reinforces this finding. In addition, we
have already found that emissions from nonroad engines significantly
contribute to air pollution that may reasonably be anticipated to
endanger public welfare due to regional haze and visibility impairment.
67 FR 68242, 68243 (Nov. 8, 2002). We find here, based on the
information in section II of this preamble and chapter 2 of the draft
RIA, that emissions from the new nonroad diesel engines covered by this
proposal likewise contribute to regional haze and to visibility
impairment that may reasonably be anticipated to endanger public
welfare. Taken together, these findings indicate the appropriateness of
the nonroad diesel engine standards proposed today for purposes of
section 213(a)(3) and (4) of the Act.
Section 211(c) of the CAA allows us to regulate fuels where
emission products of the fuel either: (1) Cause or contribute to air
pollution that reasonably may be anticipated to endanger public health
or welfare, or (2) will impair to a significant degree the performance
of any emission control device or system which is in general use, or
which the Administrator finds has been developed to a point where in a
reasonable time it will be in general use were such a regulation to be
promulgated. This rule meets both of these criteria. SOx and sulfate PM
emissions from nonroad, locomotive, marine and diesel vehicles are due
to sulfur in diesel fuel. As discussed above, emissions of these
pollutants cause or contribute to ambient levels of air pollution that
endanger public health and welfare. Control of sulfur to 500 ppm for
this fuel would lead to significant, cost-effective reductions in
emissions of these pollutants. The substantial adverse effect of high
sulfur levels on the performance of diesel emission control devices or
systems that would be expected to be used to meet the nonroad standards
is discussed in detail in section III. Control of sulfur to 15 ppm in
nonroad diesel fuel would enable emissions control technology that will
achieve significant, cost-
[[Page 28337]]
effective reduction in emissions of these pollutants, as discussed in
section II below. In addition, our authority under section 211(c) is
discussed in more detail in Appendix A to the draft RIA.
II. What Is the Air Quality Impact of the Sources Covered by the
Proposed Rule?
With this proposal, EPA is acting to extend highway types of
emission controls to another major source of diesel engine emissions,
nonroad diesel engines. These emissions are significant contributors to
atmospheric pollution from particulate matter, ozone and a variety of
toxic air pollutants. In our most recent nationwide inventory used for
this proposal (1996), the nonroad diesels affected by this proposal \8\
contribute over 43 percent of diesel PM emissions from mobile sources,
up to 18 percent of PM2.5 emissions in urban areas, and up
to 14 percent of NOX emissions in urban areas.
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\8\ For NOX and PM2.5 this includes all
land-based nonroad diesel engines, but not locomotive, commercial
marine vessel, and recreational marine vessel engines. Since the
latter three engine categories are affected by the fuel sulfur
portions of the proposal, they are included for SO2.
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Without further control beyond those standards we have already
adopted, by the year 2020, these engines will emit 62 percent of diesel
PM emissions from mobile sources, up to 19 percent of PM2.5
emissions in urban areas, and up to 20 percent of NOX
emissions in urban areas.
When fully implemented, this proposal would reduce nonroad diesel
PM2.5 and NOX emissions by more than 90 percent.
It will also virtually eliminate nonroad diesel SOx
emissions, which amounted to nearly 230,000 tons in 1996, and would
otherwise grow to approximately 340,000 tons by 2020.
These dramatic reductions in nonroad emissions are a critical part
of the effort by Federal, State and local governments to reduce the
health-related impacts of air pollution and to reach attainment of the
NAAQS for PM and ozone, as well as to improve other environmental
effects such as atmospheric visibility. Based on the most recent data
available for this rule (1999-2001), such problems are widespread in
the United States. There are over 65 million people living in counties
with monitored PM2.5 levels exceeding the PM2.5
NAAQS, and 111 million people living in counties with monitored
concentrations exceeding the 8-hour ozone NAAQS. Figure II.-1
illustrates the widespread nature of these problems. Shown in this
figure are counties exceeding either or both of the two NAAQS plus
mandatory Federal Class I areas, which have particular needs for
reductions in atmospheric haze.
[GRAPHIC] [TIFF OMITTED] TP23MY03.000
As we will describe later in this preamble, the air quality
improvements expected from this proposal is anticipated to produce
major benefits to human health and welfare, with a combined value in
excess of half a
[[Page 28338]]
trillion dollars between 2007 and 2030. By the year 2030, this proposed
rule would be expected to prevent approximately 9,600 deaths per year
from premature mortality, and 16,000 nonfatal heart attacks. It is
estimated to also prevent 14,000 acute bronchitis attacks in children,
260,000 respiratory symptoms in children, and nearly 1 million lost
work days in 2030. The reductions will also improve visibility.
In the remainder of this section we will describe in more detail
the air pollution problems associated with emissions from nonroad
diesel engines, and the emission and air quality benefits we expect to
realize from the fuel and engine controls in this proposal.
A. Overview
The emissions from nonroad engines that are being directly
controlled by the standards in this rulemaking are NOX, PM
and NMHC, and to a lesser extent, CO. Gaseous air toxics from nonroad
diesels will also be reduced as a consequence of the proposed
standards. In addition there will be a substantial reduction in
SOx emissions resulting from the proposed reduction in
sulfur level in diesel fuel.
From a public health perspective, we are primarily concerned with
nonroad engine contributions to atmospheric levels of particulate
matter in general, diesel PM in particular and various gaseous air
toxics emitted by diesel engines, and ozone.\9\ We will first review
important public health effects linked to these pollutants, briefly
describing the human health effects and the current and expected future
ambient levels of direct or indirectly caused pollution. Our
presentation will show that substantial further reductions of these
pollutants, and the underlying emissions from nonroad diesel engines,
are needed to protect public health.
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\9\ Ambient particulate matter from nonroad diesel engine is
associated with the direct emission of diesel particulate matter,
and with particulate matter formed indirectly in the atmosphere by
NOX and SOx emissions (and to a lesser extent
NMHC emissions). Both NOX and NMHC participate in the
atmospheric chemical reactions that produce ozone.
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Following discussion of health effects, we will discuss a number of
welfare effects associated with emissions from diesel engines. These
effects include atmospheric visibility impairment, ecological and
property damage caused by acid deposition, eutrophication and
nitrification of surface waters, environmental threats posed by
polycyclic organic matter (POM) deposition, and plant and crop damage
from ozone. Once again, the information available to us indicates a
continuing need for further nonroad emission reductions to bring about
improvements in air quality.
Next, we will describe our understanding of the engine emission
inventories for the primary pollutants affected by the proposal. As
noted above, these include PM, NOX, SOX, Air
Toxics and HC. We will present current and projected future levels of
emissions for the base case, including anticipated reductions from
control programs already adopted by EPA and the States, but without the
controls proposed today. Then we will identify expected emission
reductions from nonroad engines. These reductions will make important
contributions to controlling the health and welfare problems associated
with ambient PM and ozone levels and with diesel related air toxics.
While the material we will present in this section will describe
our understanding of the need for control of nonroad engine emissions
and the air quality improvements we expect to realize, this section is
not an exhaustive treatment of these issues. For a fuller understanding
of the topics treated here, you should refer to the extended
presentations in the Draft Regulatory Impact Analysis accompanying this
proposal.
B. Public Health Impacts
1. Particulate Matter
Particulate matter (PM) represents a broad class of chemically and
physically diverse substances. It can be principally characterized as
discrete particles that exist in the condensed (liquid or solid) phase
spanning several orders of magnitude in size. PM10 refers to
particles with an aerodynamic diameter less than or equal to a nominal
10 micrometers. Fine particles refer to those particles with an
aerodynamic diameter less than or equal to a nominal 2.5 micrometers
(also known as PM2.5), and coarse fraction particles are
those particles with an aerodynamic diameter greater than 2.5 microns,
but less than or equal to a nominal 10 micrometers. Ultrafine PM refers
to particles with diameters of less than 100 nanometers (0.1
micrometers). The health and environmental effects of PM are associated
with fine PM fraction and, in some cases, to the size of the particles.
Specifically, larger particles (10 [mu]m) tend to be removed
by the respiratory clearance mechanisms whereas smaller particles are
deposited deeper in the lungs. Also, particles scatter light
obstructing visibility.
The emission sources, formation processes, chemical composition,
atmospheric residence times, transport distances and other parameters
of fine and coarse particles are distinct. Fine particles are directly
emitted from combustion sources and are formed secondarily from gaseous
precursors such as sulfur dioxide (SOX), oxides of nitrogen
(NOX), or organic compounds. Fine particles are generally
composed of sulfate, nitrate, chloride, ammonium compounds, organic
carbon, elemental carbon, and metals. Nonroad diesels currently emit
high levels of NOX which react in the atmosphere to form
secondary PM2.5 (namely ammonium nitrate). Nonroad diesel
engines also emit SO2 and HC which react in the atmosphere
to form secondary PM2.5 (namely sulfates and organic
carbonaceous PM2.5). Combustion of coal, oil, diesel,
gasoline, and wood, as well as high temperature process sources such as
smelters and steel mills, produce emissions that contribute to fine
particle formation. In contrast, coarse particles are typically
mechanically generated by crushing or grinding. They include
resuspended dusts and crustal material from paved roads, unpaved roads,
construction, farming, and mining activities. These coarse particles
can be either natural in source such as road dust or anthropogenic.
Fine particles can remain in the atmosphere for days to weeks and
travel through the atmosphere hundreds to thousands of kilometers,
while coarse particles deposit to the earth within minutes to hours and
within tens of kilometers from the emission source.
The relative contribution of various chemical components to
PM2.5 varies by region of the country. Data on
PM2.5 composition are available from the EPA Speciation
Trends Network in 2001 and the Interagency Monitoring of PROtected
Visual Environments (IMPROVE) network in 1999 covering both urban and
rural areas in numerous regions of the U.S. These data show that
carbonaceous PM2.5 makes up the major component for
PM2.5 in both urban and rural areas in the western U.S.
Carbonaceous PM2.5 includes both elemental and organic
carbon. Nitrates formed from NOX also play a major role in
the western U.S., especially in the California area where it is
responsible for about a quarter of the ambient PM2.5
concentrations. Sulfate plays a lesser role in these regions. For the
eastern and mid U.S., these data show that both sulfates and
carbonaceous PM2.5 are major contributors to ambient
PM2.5 in both urban and rural areas. In some eastern areas,
carbonaceous PM2.5 is responsible for up to half of ambient
PM2.5 concentrations. Sulfate is also a
[[Page 28339]]
major contributor to ambient PM2.5 in the eastern U.S. and
in some areas make greater contributions than carbonaceous
PM2.510 11
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\10\ Rao, Venkatesh; Frank, N.; Rush, A.; and Dimmick, F.
(November 13-15, 2002). Chemical speciation of PM2.5 in
urban and rural areas (November 13-15, 2002) In the Proceedings of
the Air & Waste Management Association Symposium on Air Quality
Measurement Methods and Technology, San Francisco Meeting.
\11\ EPA (2002) Latest Finds on National Air Quality, EPA 454/K-
02-001.
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Nonroad engines, and most importantly nonroad diesel engines,
contribute significantly to ambient PM2.5 levels, largely
through emissions of carbonaceous PM2.5. Carbonaceous
PM2.5 is a major portion of ambient PM2.5,
especially in populous urban areas. Nonroad diesels also emit high
levels of NOX which react in the atmosphere to form
secondary PM2.5 (namely nitrate). Nonroad diesels also emit
SO2 and NMHC which react in the atmosphere to form secondary
PM2.5 (namely sulfates and organic carbonaceous
PM2.5). For more details, consult the draft RIA for this
proposed rule.
Diesel particles from nonroad diesel are a component of both coarse
and fine PM, but fall mainly in the fine (and even ultrafine) size
range. As discussed later, diesel PM also contains small quantities of
numerous mutagenic and carcinogenic compounds associated with the
particulate (and also organic gases). In addition, while toxic trace
metals emitted by nonroad diesel engines represent a very small portion
of the national emissions of metals (less than one percent) and a small
portion of diesel PM (generally less than one percent of diesel PM), we
note that several trace metals of potential toxicological significance
and persistence in the environment are emitted by diesel engines. These
trace metals include chromium, manganese, mercury and nickel. In
addition, small amounts of dioxins have been measured in highway engine
diesel exhaust, some of which may partition into the particulate phase;
dioxins through out the environment are a major health concern
(although the diesel contribution has not been judged significant at
this point). Diesel engines also emit polycyclic organic matter (POM),
including polycyclic aromatic hydrocarbons (PAH), which can be present
in both gas and particle phases of diesel exhaust. Many PAH compounds
are classified by EPA as probable human carcinogens.
For additional, detailed, information on PM beyond that summarized
below, see the draft Regulatory Impact Analysis.
a. Health Effects of PM2.5 and PM10
Scientific studies show ambient PM (which is attributable to a
number of sources, including nonroad diesel) is associated with a
series of adverse health effects. These health effects are discussed in
detail in the EPA Criteria Document for PM as well as the draft updates
of this document released in the past year.12 13 In
addition, EPA's final ``Health Assessment Document for Diesel Engine
Exhaust,'' (the Diesel HAD) also reviews health effects information
related to diesel exhaust as a whole including diesel PM, which is one
component of ambient PM.\14\
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\12\ U.S. EPA (1996.) Air Quality Criteria for Particulate
Matter--Volumes I, II, and III, EPA, Office of Research and
Development. Report No. EPA/600/P-95/001a-cF. This material is
available electronically at http://www.epa.gov/ttn/oarpg/ticd.html.
\13\ U.S. EPA (2002). Air Quality Criteria for Particulate
Matter--Volumes I and II (Third External Review Draft) This material
is available electronically at http://cfpub.epa.gov/ncea/cfm/
partmatt.cfm.
\14\ U.S. EPA (2002). Health Assessment Document for Diesel
Engine Exhaust. EPA/600/8-90/057F Office of Research and
Development, Washington DC. This document is available
electronically at http://cfpub.epa.gov/ncea/cfm/
recordisplay.cfm?deid=29060.
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As described in these documents, health effects associated with
short-term variation in ambient particulate matter (PM) have been
indicated by epidemiologic studies showing associations between
exposure and increased hospital admissions for ischemic heart disease,
heart failure, respiratory disease, including chronic obstructive
pulmonary disease (COPD) and pneumonia. Short-term elevations in
ambient PM have also been associated with increased cough, lower
respiratory symptoms, and decrements in lung function. Short-term
variations in ambient PM have also been associated with increases in
total and cardiorespiratory daily mortality. Studies examining
populations exposed to different levels of air pollution over a number
of years, including the Harvard Six Cities Study and the American
Cancer Society Study suggest an association between exposure to ambient
PM2.5 and premature mortality, including deaths attributed
to lung cancer.15 16 Two studies further analyzing the
Harvard Six Cities Study's air quality data have also established a
specific influence of mobile source-related PM2.5 on daily
mortality \17\ and a concentration-response function for mobile source-
associated PM2.5 and daily mortality.\18\ Another recent
study in 14 U.S. cities examining the effect of PM10 on
daily hospital admissions for cardiovascular disease found that the
effect of PM10 was significantly greater in areas with a
larger proportion of PM10 coming from motor vehicles,
indicating that PM10 from these sources may have a greater
effect on the toxicity of ambient PM10 when compared with
other sources.\19\ Additional studies have associated changes in heart
rate and/or heart rhythm in addition to changes in blood
characteristics with exposure to ambient PM.20 21 For
additional information on health effects, see the draft RIA.
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\15\ Dockery, DW; Pope, CA, III; Xu, X; et al. (1993) An
association between air pollution and mortality in six U.S. cities.
N Engl J Med 329:1753-1759.
\16\ Pope, CA, III; Thun, MJ; Namboordiri, MM; et al. (1995)
Particulate air pollution as a predictor of mortality in a
prospective study of U.S. adults. Am J Respir Crit Care Med 151:669-
674.
\17\ Laden F; Neas LM; Dockery DW; et al. (2000) Association of
fine particulate matter from different sources with daily mortality
in six U.S. cities. Environ Health Perspect 108(10):941-947.
\18\ Schwartz J; Laden F; Zanobetti A. (2002) The concentration-
response relation between PM(2.5) and daily deaths. Environ Health
Perspect 110(10): 1025-1029.
\19\ Janssen NA; Schwartz J; Zanobetti A.; et al. (2002) Air
conditioning and source-specific particles as modifiers of the
effect of PM10 on hospital admissions for heart and lung
disease. Environ Health Perspect 110(1):43-49.
\20\ Pope CA III, Verrier RL, Lovett EG; et al. (1999) Heart
rate variability associated with particulate air pollution. Am Heart
J 138(5 Pt 1):890-899.
\21\ Magari SR, Hauser R, Schwartz J; et al. (2001) Association
of heart rate variability with occupational and environmental
exposure to particulate air pollution. Circulation 104(9):986-991.
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The health effects of PM10 are similar to those of
PM2.5, since PM10 includes all of
PM2.5 plus the coarse fraction from 2.5 to 10 micrometers in
size. EPA is also evaluating the health effects of PM between 2.5 and
10 micrometers in the draft revised Criteria Document. As discussed in
the Diesel HAD and other studies, most diesel PM is smaller than 2.5
micrometers.\22\ Both fine and coarse fraction particles can enter and
deposit in the respiratory system.
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\22\ U.S. EPA (1985). Size specific total particulate emission
factor for mobile sources. EPA 460/3-85-005. Office of Mobile
Sources, Ann Arbor, MI.
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In addition to the information in the draft revised Criteria
Document, the relevance of health effects associated with on-road
diesel engine-generated PM to nonroad applications is supported by the
observation in the Diesel HAD that the particulate characteristics in
the zone around nonroad diesel engines is likely to be substantially
the same as published air quality measurements made along busy
roadways.
Of particular relevance to this rule is a recent cohort study which
examined the association between mortality and
[[Page 28340]]
residential proximity to major roads in the Netherlands. Examining a
cohort of 55 to 69 year-olds from 1986 to1994, the study indicated that
long-term residence near major roads, an index of exposure to primary
mobile source emissions (including diesel exhaust), was significantly
associated with increased cardiopulmonary mortality.\23\ Other studies
have shown children living near roads with high truck traffic density
have decreased lung function and greater prevalence of lower
respiratory symptoms compared to children living on other roads.\24\ A
recent review of epidemiologic studies examining associations between
asthma and roadway proximity concluded that some coherence was evident
in the literature, indicating that asthma, lung function decrement,
respiratory symptoms, and other respiratory problems appear to occur
more frequently in people living near busy roads.\25\ As discussed
later, nonroad diesel engine emissions, especially particulate, are
similar in composition to those from highway diesel vehicles. Although
difficult to associate directly with PM2.5, these studies
indicate that direct emissions from mobile sources, and diesel engines
specifically, may explain a portion of respiratory health effects
observed in larger-scale epidemiologic studies. Recent studies
conducted in Los Angeles have illustrated that a substantial increase
in the concentration of ultrafine particles is evident in locations
near roadways, indicating substantial differences in the nature of PM
immediately near mobile source emissions.\26\
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\23\ Hoek, G; Brunekreef, B; Goldbohm, S; et al. (2002)
Association between mortality and indicators of traffic-related air
pollution in the Netherlands: a cohort study. Lancet 360(9341):
1203-1209.
\24\ Brunekreef, B; Janssen NA; de Hartog, J; et al. (1997) Air
pollution from traffic and lung function in children living near
motor ways. Epidemiology (8): 298-303.
\25\ Delfino RJ. (2002) Epidemiologic evidence for asthma and
exposure to air toxics: linkages between occupational, indoor, and
community air pollution research. Env Health Perspect Suppl 110(4):
573-589.
\26\ Yifang Zhu, William C. Hinds, Seongheon Kim, Si Shen and
Constantinos Sioutas Zhu Y; Hinds WC; Kim S; et al. (2002) Study of
ultrafine particles near a major highway with heavy-duty diesel
traffic. Atmos Environ 36(27): 4323-4335.
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Also, as discussed in more detail later, in addition to its
contribution to ambient PM inventories, diesel PM is of special concern
because diesel exhaust has been associated with an increased risk of
lung cancer. As also discussed later in more detail, we concluded that
diesel exhaust ranks with other substances that the national-scale air
toxics assessment suggests pose the greatest relative risk.
b. Current and Projected Levels
There are NAAQS for both PM10 and PM2.5.
Violations of the annual PM2.5 standard are much more
widespread than are violations of the PM10 standards.
Emission reductions needed to attain the PM2.5 standards
will also assist in attaining and maintaining compliance with the
PM10 standards. Thus, since most PM emitted by diesel
nonroad engines is fine PM, the emission controls proposed today should
contribute to attainment and maintenance of the existing PM NAAQS. More
broadly, the proposed standards will benefit public health and welfare
through reductions in direct diesel PM and reductions of
NOX, SOX, and NMHCs which contribute to secondary
formation of PM. The reductions from these proposed rules will assist
States as they implement local controls as needed to help their areas
attain and maintain the standards.
i. PM10 Levels
The current NAAQS for PM10 were established in 1987. The
primary (health-based) and secondary (public welfare based) standards
for PM10 include both short- and long-term NAAQS. The short-
term (24 hour) standard of 150 ug/m3 is not to be exceeded
more than once per year on average over three years. The long-term
standard specifies an expected annual arithmetic mean not to exceed 50
ug/m3 averaged over three years.
Currently, 29 million people live in PM10 nonattainment
areas. There are currently 58 moderate PM10 nonattainment
areas with a total population of 6.8 million. The attainment date for
the initial moderate PM10 nonattainment areas, designated by
operation of law on November 15, 1990, was December 31, 1994. Several
additional PM10 nonattainment areas were designated on
January 21, 1994, and the attainment date for these areas was December
31, 2000. There are an additional 8 serious PM10
nonattainment areas with a total affected population of 22.7 million.
According to the Act, serious PM10 nonattainment areas must
attain the standards no later than 10 years after designation. The
initial serious PM10 nonattainment areas were designated
January 18, 1994, and had an attainment date set by the Act of December
31, 2001. The Act provides that EPA may grant extensions of the serious
area attainment dates of up to 5 years, provided that the area
requesting the extension meets the requirements of section 188(e) of
the Act. Four serious PM10 nonattainment areas (Phoenix,
Arizona; Coachella Valley, South Coast (Los Angeles), and Owens Valley,
California) have received extensions of the December 31, 2001,
attainment date and thus have new attainment dates of December 31,
2006.\27\ While all of these areas are expected to be in attainment
before the emission reductions from this proposed rule are expected to
occur, these reductions will be important to assist these areas in
maintaining the standards.
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\27\ EPA has also proposed to grant Las Vegas, Nevada, an
extension until December 31, 2006.
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ii. PM2.5 Levels
The need for reductions in the levels of PM2.5 is
widespread. Figure II-1 at the beginning of this air quality section
highlighted monitor locations measuring concentrations above the level
of the NAAQS. As can be seen from that figure, high ambient levels are
widespread throughout the country.
The NAAQS for PM2.5 were established by EPA in 1997 (62
FR 38651, July 18, 1997). The short term (24-hour) standard is set at a
level of 65 [mu]g/m3 based on the 98th percentile
concentration averaged over three years. (This air quality statistic
compared to the standard is referred to as the ``design value.'') The
long-term standard specifies an expected annual arithmetic mean not to
exceed 15 ug/m3 averaged over three years.
Current PM2.5 monitored values for 1999-2001, which
cover counties having about 75 percent of the country's population,
indicate that at least 65 million people in 129 counties live in areas
where annual design values of ambient fine PM violate the
PM2.5 NAAQS. There are an additional 9 million people in 20
counties where levels above the NAAQS are being measured, but there are
insufficient data at this time to calculate a design value in
accordance with the standard, and thus determine whether these areas
are violating the PM2.5 NAAQS. In total, this represents 37
percent of the counties and 64 percent of the population in the areas
with monitors with levels above the NAAQS. Furthermore, an additional
14 million people live in 41 counties that have air quality
measurements within 10 percent of the level of the standard. These
areas, although not currently violating the standard, will also benefit
from the additional reductions from this rule in order to ensure long
term maintenance.
Our air quality modeling performed for this proposal also indicates
that similar conditions are likely to continue
[[Page 28341]]
to exist in the future in the absence of additional controls. For
example, in 2020 based on emission controls currently adopted, we
project that 66 million people will live in 79 counties with average
PM2.5 levels above 15 ug/m\3\. In 2030, the number of people
projected to live in areas exceeding the PM2.5 standard is
expected to increase to 85 million in 107 counties. An additional 24
million people are projected to live in counties within 10 percent of
the standard in 2020, which will increase to 64 million people in 2030.
Our modeling also indicates that the reductions we are expecting
will make a substantial contribution to reducing exposures in these
areas.\28\ In 2020, the number of people living in counties with
PM2.5 levels above the NAAQS would be reduced from 66
million to 60 million living in 67 counties, which reflects a reduction
of 9 percent in potentially exposed population and 15 percent of the
number of counties. In 2030, there would be a reduction from 85 million
people to 71 million living in 84 counties. These represent even
greater improvements than projected for 2020 (numbers of people
potentially exposed down 16 percent and number of counties down 21
percent). Furthermore, our modeling also shows that the emission
reductions would assist areas with future maintenance of the standards.
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\28\ The results illustrate the type of PM changes for the
preliminary control option, as discussed in the Draft RIA in section
3.6. The proposal differs from the modeled control case based on
updated information; however, we believe that the net results would
approximate future emissions, although we anticipate the PM
reductions might be slightly smaller.
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We estimate that the reduction of PM levels expected from this
proposed rule would produce nationwide air quality improvements in PM
levels. On a population weighted basis, the average change in future
year annual averages would be a decrease of 0.33 ug/m\3\ in 2020, and
0.46 ug/m\3\ in 2030. The reductions are discussed in more detail in
chapter 2 of the draft RIA.
While the final implementation process for bringing the nation's
air into attainment with the PM2.5 NAAQS is still being
completed in a separate rulemaking action, the basic framework is well
defined by the statute. EPA's current plans call for designating
PM2.5 nonattainment areas in late-2004. Following
designation, Section 172(b) of the Clean Air Act allows states up to
three years to submit a revision to their state implementation plan
(SIP) that provides for the attainment of the PM2.5
standard. Based on this provision, states could submit these SIPs as
late as the end of 2007. Section 172(a)(2) of the Clean Air Act
requires that these SIP revisions demonstrate that the nonattainment
areas will attain the PM2.5 standard as expeditiously as
practicable but no later than five years from the date that the area
was designated nonattainment. However, based on the severity of the air
quality problem and the availability and feasibility of control
measures, the Administrator may extend the attainment date ``for a
period of no greater than 10 years from the date of designation as
nonattainment.'' Therefore, based on this information, we expect that
most or all areas will need to attain the PM2.5 NAAQS in the
2009 to 2014 time frame, and then be required to maintain the NAAQS
thereafter.
Since the emission reductions expected from this proposal would
begin in this same time frame, the projected reductions in nonroad
emissions would be used by states in meeting the PM2.5
NAAQS. States and state organizations have told EPA that they need
nonroad diesel engine reductions in order to be able to meet and
maintain the PM2.5 NAAQS as well as visibility regulations,
especially in light of the otherwise increasing emissions from nonroad
sources without more stringent standards.29 30 31
Furthermore, this action would ensure that nonroad diesel emissions
will continue to decrease as the fleet turns over in the years beyond
2014; these reductions will be important for maintenance of the NAAQS
following attainment. The future reductions are also important to
achieve visibility goals, as discussed later.
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\29\ California Air Resources Board and New York State
Department of Environmental Conservation (April 9, 2002), Letter to
EPA Administrator Christine Todd Whitman.
\30\ State and Territorial Air Pollution Program Administrators
(STAPPA) and Association of Local Air Pollution Control Officials
(ALAPCO) (December 17, 2002), Letter to EPA Assistant Administrator
Jeffrey R. Holmstead.
\31\ Western Regional Air Partnership (WRAP) (January 28, 2003),
Letter to Governor Christine Todd Whitman.
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2. Air Toxics
a. Diesel Exhaust
A number of health studies have been conducted regarding diesel
exhaust including epidemiologic studies of lung cancer in groups of
workers, and animal studies focusing on non-cancer effects specific to
diesel exhaust. Diesel exhaust PM (including the associated organic
compounds which are generally high molecular weight hydrocarbon types
but not the more volatile gaseous hydrocarbon compounds) is generally
used as a surrogate measure for diesel exhaust.
i. Potential Cancer Effects of Diesel Exhaust
In addition to its contribution to ambient PM inventories, diesel
exhaust is of specific concern because it has been judged to pose a
lung cancer hazard for humans as well as a hazard from noncancer
respiratory effects.
EPA recently released its ``Health Assessment Document for Diesel
Engine Exhaust,'' (the Diesel HAD).\32\ There, diesel exhaust was
classified as likely to be carcinogenic to humans by inhalation at
environmental exposures, in accordance with the revised draft 1996/1999
EPA cancer guidelines. A number of other agencies (National Institute
for Occupational Safety and Health, the International Agency for
Research on Cancer, the World Health Organization, California EPA, and
the U.S. Department of Health and Human Services) have made similar
classifications. It should be noted that the conclusions in the Diesel
HAD were based on diesel engines currently in use, including nonroad
diesel engines such as those found in bulldozers, graders, excavators,
farm tractor drivers and heavy construction equipment. As new diesel
engines with significantly cleaner exhaust emissions replace existing
engines, the conclusions of the Diesel HAD will need to be reevaluated.
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\32\ U.S. EPA (2002). Health Assessment Document for Diesel
Engine Exhaust. EPA/600/8-90/057F Office of Research and
Development, Washington DC. This document is available
electronically at http://cfpub.epa.gov/ncea/cfm/
recordisplay.cfm?deid=29060.
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For the EPA Diesel HAD, EPA reviewed 22 epidemiologic studies in
detail, finding increased lung cancer risk in 8 out of 10 cohort
studies and 10 out of 12 case-control studies. Relative risk for lung
cancer associated with exposure range from 1.2 to 2.6. In addition, two
meta-analyses of occupational studies of diesel exhaust and lung cancer
have estimated the smoking-adjusted relative risk of 1.35 and 1.47,
examining 23 and 30 studies, respectively.33 34 That is,
these two studies show an overall increase in lung cancer for the
exposed groups of 35 percent and 47 percent compared to the groups not
exposed to diesel exhaust. In the EPA Diesel HAD, EPA selected 1.4
[[Page 28342]]
as a reasonable estimate of occupational relative risk for further
analysis.
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\33\ Bhatia, R., Lopipero, P., Smith, A. (1998). Diesel exhaust
exposure and lung cancer. Epidemiology 9(1):84-91.
\34\ Lipsett, M: Campleman, S.; (1999). Occupational exposure to
diesel exhaust and lung cancer: a meta-analysis. Am J Public Health
80(7):1009-1017.
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EPA generally derives cancer unit risk estimates to calculate
population risk more precisely from exposure to carcinogens. In the
simplest terms, the cancer unit risk is the increased risk associated
with average lifetime exposure of 1 ug/m\3\. EPA concluded in the
Diesel HAD that it is not possible currently to calculate a cancer unit
risk for diesel exhaust due to a variety of factors that limit the
current studies, such as a lack of standard exposure metric for diesel
exhaust and the absence of quantitative exposure characterization in
retrospective studies.
EPA generally derives cancer unit risk estimates to calculate
population risk more precisely from exposure to carcinogens. In the
simplest terms, the cancer unit risk is the increased risk associated
with average lifetime exposure of 1 ug/m\3\. EPA concluded in the
Diesel HAD that it is not possible currently to calculate a cancer unit
risk for diesel exhaust due to a variety of factors that limit the
current studies, such as lack of an adequate dose-response relationship
between exposure and cancer incidence.
However, in the absence of a cancer unit risk, the EPA Diesel HAD
sought to provide additional insight into the possible ranges of risk
that might be present in the population. Such insights, while not
confident or definitive, nevertheless contribute to an understanding of
the possible public health significance of the lung cancer hazard. The
possible risk range analysis was developed by comparing a typical
environmental exposure level to a selected range of occupational
exposure levels and then proportionally scaling the occupationally
observed risks according to the exposure ratio's to obtain an estimate
of the possible environmental risk. If the occupational and
environmental exposures are similar, the environmental risk would
approach the risk seen in the occupational studies whereas a much
higher occupational exposure indicates that the environmental risk is
lower than the occupational risk. A comparison of environmental and
occupational exposures showed that for certain occupations the
exposures are similar to environmental exposures while, for others,
they differ by a factor of about 200 or more.
The first step in this process is to note that the occupational
relative risk of 1.4, or a 40 percent from increased risk compared to
the typical 5 percent lung cancer risk in the U.S. population,
translates to an increased risk of 2 percent (or 10-2) for
these diesel exhaust exposed workers. The Diesel HAD derived a typical
nationwide average environmental exposure level of 0.8 ug./m\3\ for
diesel PM from highway sources for 1996. Diesel PM is a surrogate for
diesel exhaust and, as mentioned above, has been classified as a
carcinogen by some agencies.
This estimate was based on national exposure modeling; the
derivation of this exposure is discussed in detail in the EPA Diesel
HAD. The possible risk range in the environment was estimated by taking
the relative risks in the occupational setting, EPA selected 1.4 and
converting this to absolute risk of 2% and then ratioing this risk by
differences in the occupational vs environmental exposures of interest.
A number of calculations are needed to accomplish this, and these can
be seen in the EPA Diesel HAD. The outcome was that environmental risks
from diesel exhaust exposure could range from a low of 10-4
to 10-5 or be as high as 10-3 this being a
reflection of the range of occupational exposures that could be
associated with the relative and absolute risk levels observed in the
occupational studies.
While these risk estimates are exploratory and not intended to
provide a definitive characterization of cancer risk, they are useful
in gauging the possible range of risk based on reasonable judgement. It
is important to note that the possible risks could also be higher or
lower and a zero risk cannot be ruled out. Some individuals in the
population may have a high tolerance to exposure from diesel exhaust
and low cancer susceptibility. Also, one cannot rule out the
possibility of a threshold of exposure below which there is no cancer
risk, although evidence has not been seen or substantiated on this
point.
Also, as discussed in the Diesel HAD, there is a relatively small
difference between some occupational settings where increased lung
cancer risk is reported and ambient environmental exposures. The
potential for small exposure differences underscores the
appropriateness of the extrapolation from occupational risk to ambient
environmental exposure levels is reasonable and appropriate.
EPA also recently completed an assessment of air toxic emissions
(the National-Scale Air Toxics Assessment or NATA) and their associated
risk, and we concluded that diesel exhaust ranks with other substances
that the national-scale assessment suggests pose the greatest relative
risk.\35\ This assessment estimates average population inhalation
exposures to diesel PM in 1996 for nonroad as well as on-road sources.
These are the sum of ambient levels in various locations weighted by
the amount of time people spend in each of the locations. This analysis
shows a somewhat higher diesel exposure level than the 0.8 ug/m\3\ used
to develop the risk perspective in the Diesel HAD. The NATA levels are
1.4 ug/m\3\ total with an on-road source contribution of 0.5 ug/m\3\ to
average nationwide exposure in 1996 and a nonroad source contribution
of 0.9 ug/m\3\. The average urban exposure concentration was 1.6 ug/
m\3\ and the average rural concentration was 0.55 ug/m\3\. In five
percent of urban census tracts across the United States, average
concentrations were above 4.3 ug/m\3\. The Diesel HAD states that use
of the NATA exposure number results instead of the 0.8 ug/m\3\ results
in a similar risk perspective.
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\35\ U.S. EPA (2002). National-Scale Air Toxics Assessment. This
material is available electronically at http://www.epa.gov/ttn/atw/
nata/.
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In 2001, EPA completed a rulemaking on mobile source air toxics
with a determination that diesel particulate matter and diesel exhaust
organic gases be identified as a Mobile Source Air Toxic (MSAT).\36\
This determination was based on a draft of the Diesel HAD on which the
Clean Air Scientific Advisory Committee of the Science Advisory Board
had reached closure. The purpose of the MSAT list is to provide a
screening tool that identifies compounds emitted from motor vehicles or
their fuels for which further evaluation of emissions controls is
appropriate.
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\36\ U.S. EPA (2001). Control of Emissions of Hazardous Air
Pollutants from Mobile Sources; Final Rule. 66 FR 17230-17273 (March
29, 2001).
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In summary, even though EPA does not have a specific carcinogenic
potency with which to accurately estimate the carcinogenic impact of
diesel PM, the likely hazard to humans at environmental exposure levels
leads us to conclude that diesel exhaust emissions of PM and organic
gases should be reduced from nonroad engines in order to protect public
health.
ii. Other Health Effects of Diesel Exhaust
The acute and chronic exposure-related effects of diesel exhaust
emissions are also of concern to the Agency. The Diesel HAD established
an inhalation Reference Concentration (RfC) specifically based on
animal studies of diesel exhaust. An RfC is defined by EPA as ``an
estimate of a continuous inhalation exposure to the human population,
including sensitive subgroups, with uncertainty spanning
[[Page 28343]]
perhaps an order of magnitude, that is likely to be without appreciable
risks of deleterious noncancer effects during a lifetime.'' EPA derived
the RfC from consideration of four chronic rat inhalation studies
showing adverse pulmonary effects. The diesel RfC is based on a ``no
observable adverse effect'' level of 144 ug/m\3\ that is further
reduced by applying uncertainty factors of 3 for interspecies
extrapolation and 10 for human variations in sensitivity. The resulting
RfC derived in the Diesel HAD is 5 ug/m\3\ for diesel exhaust as
measured by diesel PM. This RfC does not consider allergenic effects
such as those associated with asthma or immunologic effects. There is
growing evidence that diesel exhaust can exacerbate these effects, but
the exposure-response data is presently lacking to derive an RfC.
Again, this RfC is based on animal studies and is meant to estimate
exposure that is unlikely to have deleterious effects on humans based
on those studies alone.
The Diesel HAD also briefly summarizes health effects associated
with ambient PM and the EPA's annual NAAQS for PM2.5 of 15
ug/m\3\. There is a much more extensive body of human data showing a
wide spectrum of adverse health effects associated with exposure to
ambient PM, of which diesel exhaust is an important component due to
its large contribution to ambient concentrations. The RfC is not meant
to say that 5 ug/m\3\ provides adequate public health protection for
ambient PM2.5. There may be benefits to reducing diesel PM
below 5 ug/m\3\ since diesel PM is a major contributor to ambient
PM2.5. Recent epidemiologic studies of ambient PM2.5 do not
indicate a threshold of effects at low concentrations.\37\
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\37\ EPA-SAB-Council-ADV-99-012, 1999. The Clean Air Act
Amendments Section 812 Prospective Study of Costs and Benefits
(1999): Advisory by the Health and Ecological Effects Subcommittee
on Initial Assessments of Health and Ecological Effects, Part 1.
July 28, 1999.
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Also, as mentioned earlier in the health effects discussion for
PM2.5, there are a number of other health effects associated
with PM in general, and motor vehicle exhaust including diesels in
particular, that provide additional evidence for the need for
significant emission reductions from nonroad diesel sources. For
example, the Diesel HAD notes that acute or short-term exposure to
diesel exhaust can cause acute irritation (e.g., eye, throat,
bronchial), neurophysiological symptoms (e.g., lightheadedness,
nausea), and respiratory symptoms (e.g., cough, phlegm). There is also
evidence for an immunologic effect such as the exacerbation of
allergenic responses to know allergens and asthma-like symptoms. All of
these health effects plus the designation of diesel exhaust as a likely
human carcinogen provide ample health justification for control.
iii. Ambient Levels and Exposure to Diesel Exhaust PM
Because diesel PM is part of overall ambient PM and cannot be
easily distinguished from overall PM, we do not have direct
measurements of diesel PM in the ambient air. Ambient diesel PM
concentrations are estimated instead using one of three approaches: (1)
Ambient air quality modeling based on diesel PM emission inventories;
(2) using elemental carbon concentrations in monitored data as
surrogates; or (3) using the chemical mass balance (CMB) model in
conjunction with ambient PM measurements. (Also, in addition to CMB,
UNMIX/PMF have also been used). Estimates using these three approaches
are described below. In addition, estimates developed using the first
two approaches above are subjected to a statistical comparison to
evaluate overall reasonableness of estimated concentrations. It is
important to note that, while there are inconsistencies in some of
these studies on the relative importance of gasoline and diesel PM, the
studies which are discussed in the Diesel HAD all show that diesel PM
is a significant contributor to overall ambient PM. Some of the studies
differentiate nonroad from on-road diesel PM.
(1) Air Quality Modeling
In addition to the general ambient PM modeling conducted for this
proposal, diesel PM concentrations specifically were recently estimated
for 1996 as part of NATA. In this assessment, the PM inventory
developed for the recent regulation promulgating 2007 heavy duty
vehicle standards was used. Note that the nonroad inventory used in
this modeling was based on an older version of the draft NONROAD Model
which showed higher diesel PM than the current version. Ambient impacts
of mobile source emissions were predicted using the Assessment System
for Population Exposure Nationwide (ASPEN) dispersion model. Overall
mean annual national levels for both on-road and nonroad diesels of
2.06 ug/m\3\ diesel PM were calculated with a mean of 2.41 in urban
counties and 0.74 in rural counties. These are ambient levels such as
would be seen at monitors rather than the exposure levels discussed
earlier. Over half of the diesel PM comes from nonroad diesels.
Diesel PM concentrations were also recently modeled across a
representative urban area, Houston, for 1996, using the Industrial
Source Complex Short Term (ISCST3) model. This modeling is designed to
more specifically account for local traffic patterns including diesel
truck traffic along specific roadways. The modeling in Houston suggests
strong spatial gradients for Diesel PM and indicates that ``hotspot''
concentrations can be very high, up to 8 ug/m\3\ at receptor versus a 3
ug/m\3\ average in Houston. Such concentrations are above the RfC for
diesel exhaust and indicate a potential for adverse health effects from
chronic exposure to diesel PM. These results also suggest that PM from
diesel vehicles makes a major contribution to total ambient PM
concentrations. Such ``hot spot'' concentrations along certain roadways
suggest the presence of both high localized exposures plus higher
estimated average annual exposure levels for urban centers than what
has been estimated in assessments such as NATA, which are designed to
focus on regional and national scale averages. There are similar ``hot
spot'' concentrations in the immediate vicinity of use of nonroad
equipment such as in urban construction sites.
(2) Elemental Carbon Measurements
As mentioned before, the carbonaceous component is significant in
ambient PM. The carbonaceous component consists of organic carbon and
elemental carbon. Monitoring data on elemental carbon concentrations
can be used as a surrogate to determine ambient diesel PM
concentrations. Elemental carbon is a major component of diesel
exhaust, contributing to approximately 60 to 80 percent of diesel
particulate mass, depending on engine technology, fuel type, duty
cycle, lube oil consumption, and state of engine maintenance. In most
areas, diesel engine emissions are major contributors to elemental
carbon in the ambient air, with other potential sources including
gasoline exhaust, combustion of coal, oil, or wood (including forest
fires), charbroiling, cigarette smoke, and road dust. Because of the
large portion of elemental carbon in diesel particulate matter, and the
fact that diesel exhaust is one of the major contributors to elemental
carbon in most areas, ambient diesel PM concentrations can be bounded
using elemental carbon measurements.
The measured mass of elemental carbon at a given site varies
depending on the measurement technique used. Moreover, to estimate
diesel PM concentration based on elemental
[[Page 28344]]
carbon level, one must first estimate the percentage of PM attributable
to diesel engines and the percentage of elemental carbon in diesel PM.
Thus, there are significant uncertainties in estimating diesel PM
concentrations using an elemental carbon surrogate. Depending on the
measurement technique used, and assumptions made, average nationwide
concentrations for current years of diesel PM estimated from elemental
carbon data range from about 1.2 to 2.2 ug/m\3\. EPA has compared these
estimates based on elemental carbon measurements to modeled
concentrations in NATA and concluded that the two sets of data agree
reasonably well. This performance compares favorably with the model to
monitor results for other pollutants assessed in NATA, with the
exception of benzene, for which the performance of the NATA modeling
was better. These comparisons are discussed in greater detail in the
draft RIA.
(3) Chemical Mass Balance
The third approach for estimating ambient diesel PM concentrations
uses the CMB model for source apportionment in conjunction with ambient
PM measurements and chemical source ``fingerprints'' to estimate
ambient diesel PM concentrations. The CMB model uses a statistical
fitting technique to determine how much mass from each source would be
required to reproduce the chemical fingerprint of each speciated
ambient monitor. This source apportionment technique presently does not
distinguish between on-road and nonroad but, instead, gives diesel PM
as a whole. This source apportionment technique can distinguish between
diesel and gasoline PM. Caution in interpreting CMB results is
warranted, as the use of fitting species that are not specific to the
sources modeled can lead to misestimation of source contributions.
Ambient concentrations using this approach are generally about 1 ug/
m\3\ annual average. UNMIX/PMF models show similar results. Results
from various studies are discussed in the draft RIA.
iv. Diesel Exhaust PM Exposures
Exposure of people to diesel exhaust depends on their various
activities, the time spent in those activities, the locations where
these activities occur, and the levels of diesel exhaust pollutants
(such as particulate) in those locations. The major difference between
ambient levels of diesel particulate and exposure levels for diesel
particulate is that exposure accounts for a person moving from location
to location, proximity to the emission source, and whether the exposure
occurs in an enclosed environment.
(1) Occupational Exposures
Diesel particulate exposures have been measured for a number of
occupational groups over various years but generally for more recent
years (1980s and later) rather than earlier years. Occupational
exposures had a wide range varying from 2 to 1,280 ug/m3 for
a variety of occupational groups including miners, railroad workers,
firefighters, air port crew, public transit workers, truck mechanics,
utility linemen, utility winch truck operators, fork lift operators,
construction workers, truck dock workers, short-haul truck drivers, and
long-haul truck drivers. These individual studies are discussed in the
Diesel HAD. As discussed in the Diesel HAD, the National Institute of
Occupational Safety and Health (NIOSH) has estimated a total of
1,400,000 workers are occupationally exposed to diesel exhaust from on-
road and nonroad equipment.
Many measured or estimated occupational exposures are for on-road
diesel engines although some (especially the higher ones) are for
occupational groups (e.g., fork lift operators, construction workers,
or mine workers) who would be exposed to nonroad diesel exhaust.
Sometimes, as is the case for the nonroad engines, there are only
estimates of exposure based on the length of employment or similar
factors rather than a ug/m3 level. Estimates for exposures
to diesel PM for diesel fork lift operators have been made that range
from 7 to 403 ug/m3 as reported in the Diesel HAD. In
addition, the Northeast States for Coordinated Air Use Management
(NESCAUM) is presently measuring occupational exposures to particulate
and elemental carbon near the operation of various diesel non-road
equipment. Exposure groups include agricultural farm operators, grounds
maintenance personnel (lawn and garden equipment), heavy equipment
operators conducting multiple job tasks at a construction site, and a
saw mill crew at a lumber yard. Samples will be obtained in the
breathing zone of workers. Some initial results are expected in late
2003.
(2) General Ambient Exposures
Currently, personal exposure monitors for PM cannot differentiate
diesel from other PM. Thus, we use modeling to estimate exposures.
Specifically, exposures for the general population are estimated by
first conducting dispersion modeling of both on-road and non-road
diesel emissions, described above, and then by conducting exposure
modeling. The most comprehensive modeling for cumulative exposures to
diesel PM is the NATA. This assessment calculates exposures of the
national population as a whole to a variety of air toxics, including
diesel PM. As discussed previously, the ambient levels are calculated
using the ASPEN dispersion model. The preponderance of modeled diesel
PM concentrations are within a factor of 2 of diesel PM concentrations
estimated from elemental carbon measurements.\38\ This comparison adds
credence to the modeled ASPEN results and associated exposure
assessment.
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\38\ U.S. EPA (2002). Diesel PM model-to-measurement comparison.
Prepared by ICF Consulting for EPA, Office of Transportation and Air
Quality. Report No. EPA420-D-02-004.
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The modeled ambient concentrations are used as inputs into the
Hazardous Air Pollution Exposure Model (HAPEM4) to calculate exposure
levels. Average exposures calculated nationwide are 1.44 ug/
m3 with levels of 1.64 ug/m3 for urban counties
and 0.55 ug/m3 for rural counties. Again, nonroad diesels
account for over half of this modeled exposure.
(3) Ambient Exposures--Microenvironments
One common microenvironment for diesel exposure is beside freeways.
Although freeway locations are associated mostly with on-road rather
than nonroad diesels, there are many similarities between on-road and
nonroad diesel emissions as discussed in the Diesel HAD. The California
Air Resources Board (CARB) measured elemental carbon near the Long
Beach Freeway in 1993. Levels measured ranged from 0.4 to 4.0 ug/
m3 (with one value as high as 7.5 ug/m3) above
background levels. Microenvironments associated with nonroad engines
would include construction zones. PM and elemental carbon samples are
being collected by NESCAUM in the immediate area of the nonroad engine
operations (such as at the edge or fence line of the construction
zone). Besides PM and elemental carbon levels, various toxics such as
benzene, 1,3-butadiene, formaldehyde, and acetaldehyde will be sampled.
Some initial results should be available in late 2003 and will be
especially useful since they focus on those microenvironments affected
by nonroad diesels.
Also, EPA is funding research in Fresno to measure indoor and
outdoor PM component concentrations in the homes of over 100 asthmatic
children. Some of these homes are located near
[[Page 28345]]
agricultural, construction, and utility nonroad equipment operations.
This work will measure infiltration of elemental carbon and other PM
components to indoor environments. The project also evaluates lung
function changes in the asthmatic children during fluctuations in
exposure concentrations and compositions. This information may allow an
evaluation of adverse health effects associated with exposures to
elemental carbon and other PM components from on-road and nonroad
sources. Some initial results may be available in late 2003.
b. Gaseous Air Toxics
Nonroad diesel engine emissions contain several substances known or
suspected as human or animal carcinogens, or that have noncancer health
effects. These other compounds include benzene,1,3-butadiene,
formaldehyde, acetaldehyde, acrolein, dioxin, and polycyclic organic
matter (POM). For some of these pollutants, nonroad diesel engine
emissions are believed to account for a significant proportion of total
nation-wide emissions. All of these compounds were identified as
national or regional ``risk'' drivers in the 1996 NATA. That is, these
compounds pose a significant portion of the total inhalation cancer
risk to a significant portion of the population. Mobile sources
contribute significantly to total emissions of these air toxics. As
discussed later in this section, this proposed rulemaking will result
in significant reductions of these emissions.
Benzene: Nonroad diesel engines accounted for about 3 percent of
ambient benzene emissions in 1996. Of ambient benzene levels due to
mobile sources, 5 percent in urban and 3 percent in rural areas came
from nonroad diesel.
The EPA's IRIS database lists benzene as a known human carcinogen
(causing leukemia at high, prolonged air exposures) by all routes of
exposure, and exposure is associated with additional health effects
including genetic changes in humans and animals and increased
proliferation of bone marrow cells in mice.39 40 41 42 EPA
states in its IRIS database that the data indicate a causal
relationship between benzene exposure and acute lymphocytic leukemia
and suggest a relationship between benzene exposure and chronic non-
lymphocytic leukemia and chronic lymphocytic leukemia. Respiration is
the major source of human exposure and at least half of this exposure
is attributable to gasoline vapors and automotive emissions. A number
of adverse noncancer health effects including blood disorders, such as
preleukemia and aplastic anemia, have also been associated with low-
dose, long-term exposure to benzene.43 44
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\39\ U.S. EPA (2000). Integrated Risk Information System File
for Benzene. This material is available electronically at http://
www.epa.gov/iris/subst/0276.htm.
\40\ International Agency for Research on Cancer, IARC
monographs on the evaluation of carcinogenic risk of chemicals to
humans, Volume 29, Some industrial chemicals and dyestuffs,
International Agency for Research on Cancer, World Health
Organization, Lyon, France, p. 345-389, 1982.
\41\ Irons, R.D., W.S. Stillman, D.B. Colagiovanni, and V.A.
Henry, Synergistic action of the benzene metabolite hydroquinone on
myelopoietic stimulating activity of granulocyte/macrophage colony-
stimulating factor in vitro, Proc. Natl. Acad. Sci. 89:3691-3695,
1992.
\42\ U.S. EPA (1998). Carcinogenic Effects of Benzene: An
Update, National Center for Environmental Assessment, Washington,
DC. 1998.
\43\ Aksoy, M. (1989). Hematotoxicity and carcinogenicity of
benzene. Environ. Health Perspect. 82: 193-197.
\44\ Goldstein, B.D. (1988). Benzene toxicity. Occupational
medicine. State of the Art Reviews. 3: 541-554.
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1,3-Butadiene: Nonroad diesel engines accounted for about 1.5
percent of ambient butadiene emissions in 1996. Of ambient butadiene
levels due to mobile sources, 4 percent in urban and 2 percent in rural
areas came from nonroad diesel.
EPA earlier identified 1,3-butadiene as a probable human carcinogen
in its IRIS database and recently redesignated it as a known human
carcinogen (but with a lower carcinogenic potency than previously
used).\45\ The specific mechanisms of 1,3-butadiene-induced
carcinogenesis are unknown, however, it is virtually certain that the
carcinogenic effects are mediated by genotoxic metabolites of 1,3-
butadiene. Animal data suggest that females may be more sensitive than
males for cancer effects; nevertheless, there are insufficient data
from which to draw any conclusions on potentially sensitive
subpopulations. 1,3-Butadiene also causes a variety of reproductive and
developmental effects in mice; no human data on these effects are
available. The most sensitive effect was ovarian atrophy observed in a
lifetime bioassay of female mice.\46\
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\45\ U.S. EPA (2002). Health Assessment of 1,3-Butadiene. Office
of Research and Development, National Center for Environmental
Assessment, Washington Office, Washington, DC. Report No. EPA/600/P-
98/001F.
\46\ Bevan, C; Stadler, JC; Elliot, GS; et al. (1996) Subchronic
toxicity of 4-vinylcyclohexene in rats and mice by inhalation.
Fundam. Appl. Toxicol. 32:1-10.
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Formaldehyde: Nonroad diesel engines accounted for about 22 percent
of ambient formaldehyde emissions in 1996. Of ambient formaldehyde
levels due to mobile sources, 37 percent in urban and 27 percent in
rural areas came form nonroad diesel. These figures are for tailpipe
emissions of formaldehyde. Formaldehyde in the ambient air comes not
only from tailpipe (of direct) emissions but is also formed from
photochemical reactions of hydrocarbons.
EPA has classified formaldehyde as a probable human carcinogen
based on evidence in humans and in rats, mice, hamsters, and
monkeys.\47\ Epidemiological studies in occupationally exposed workers
suggest that long-term inhalation of formaldehyde may be associated
with tumors of the nasopharyngeal cavity (generally the area at the
back of the mouth near the nose), nasal cavity, and sinus.\48\
Formaldehyde exposure also causes a range of noncancer health effects,
including irritation of the eyes (tearing of the eyes and increased
blinking) and mucous membranes. Sensitive individuals may experience
these adverse effects at lower concentrations than the general
population and in persons with bronchial asthma, the upper respiratory
irritation caused by formaldehyde can precipitate an acute asthmatic
attack. The agency is currently conducting a reassessment of risk from
inhalation exposure to formaldehyde.
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\47\ U.S. EPA (1987). Assessment of Health Risks to Garment
Workers and Certain Home Residents from Exposure to Formaldehyde,
Office of Pesticides and Toxic Substances, April 1987.
\48\ Blair, A., P.A. Stewart, R.N. Hoover, et al. (1986).
Mortality among industrial workers exposed to formaldehyde. J. Natl.
Cancer Inst. 76(6): 1071-1084.
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Acetaldehyde: Nonroad diesel engines accounted for about 34 percent
of acetaldehyde emissions in 1996. Of ambient acetaldehyde levels due
to mobile sources, 24 percent in urban and 17 percent in rural areas
came form nonroad diesel. Also, acetaldehyde can be formed
photochemically in the atmosphere. Counting both direct emissions and
photochemically formed acetaldehyde, mobile sources were responsible
for the major portion of acetaldehyde in the ambient air according to
the National-Scale Air Toxics Assessment for 1996.
Acetaldehyde is classified in EPA's IRIS database as a probable
human carcinogen and is considered moderately toxic by the inhalation,
oral, and intravenous routes.\49\ The primary acute effect of exposure
to acetaldehyde vapors is irritation of the eyes, skin, and
[[Page 28346]]
respiratory tract. At high concentrations, irritation and pulmonary
effects can occur, which could facilitate the uptake of other
contaminants. Some asthmatics have been shown to be a sensitive
subpopulation to decrements in FEV1 upon acetaldehyde inhalation.\50\
The agency is currently conducting a reassessment of risk from
inhalation exposure to acetaldehyde.
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\49\ U.S. EPA (1988). Integrated Risk Information System File of
Acetaldehyde. This material is available electronically at http://
www.epa.gov/iris/subst/0290.htm.
\50\ Myou, S.; Fujimura, M.; Nishi K.; Ohka, T.; and Matsuda, T.
(1993) Aerosolized acetaldehyde induces histamine-mediated
bronchoconstriction in asthmatics. Am Rev Respir Dis 148(4 Pt 1):
940-3.
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Acrolein: Nonroad diesel engines accounted for about 17.5 percent
of acrolein emissions in 1996. Of ambient acrolein levels due to mobile
sources, 28 percent in urban and 18 percent in rural areas came form
nonroad diesel.
Acrolein is extremely toxic to humans when inhaled, with acute
exposure resulting in upper respiratory tract irritation and
congestion. The Agency has developed a reference concentration for
inhalation (RfC) of acrolein of 0.02 micrograms/m\3\.\51\
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\51\ U.S. EPA (1993). Environmental Protection Agency,
Integrated Risk Information System (IRIS), National Center for
Environmental Assessment, Cincinnati, OH.
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Although no information is available on its carcinogenic effects in
humans, based on laboratory animal data, EPA considers acrolein a
possible human carcinogen.
Polycyclic Organic Matter (POM): POM is generally defined as a
large class of chemicals consisting of organic compounds having
multiple benzene rings and a boiling point greater than 100 degrees C.
Polycyclic aromatic hydrocarbons (PAHs) are a chemical class that is a
subset of POM. POM are naturally occurring substances that are
byproducts of the incomplete combustion of fossil fuels and plant and
animal biomass (e.g., forest fires). They occur as byproducts from
steel and coke productions and waste incineration. They also are a
component of diesel particulate emissions. Many of the compounds
included in the class of compounds known as POM are classified by EPA
as probable human carcinogens based on animal data. In particular, EPA
frequently obtains data on 7 of the POM compounds, which we analyzed
separately as a class in the 1996 NATA. Nonroad diesel engines account
for less than 1 percent of these 7 POM compounds with total mobile
sources responsible for only 4 percent of the total; most of the 7 POMs
come from area sources. For total POM compounds, mobile sources as a
whole are responsible for only 1 percent. The mobile source emission
numbers used to derive these inventories are based on only particulate
phase POM and do not include the semi-volatile phase POM levels. Were
those additional POMs included (which is now being done), these
inventory numbers would be substantially higher.
Even though mobile sources are responsible for only a small portion
of total POM emissions, the particulate reductions from today's action
will reduce these emissions.
Dioxins: Recent studies have confirmed that dioxins are formed by
and emitted from diesels (both heavy-duty diesel trucks and non-road
diesels although in very small amounts) and are estimated to account
for about 1 percent of total dioxin emissions in 1995. Recently EPA
issued a draft assessment designating one dioxin compound, 2,3,7,8-
tetrachlorodibenzo-p-dioxin as a human carcinogen and the complex
mixtures of dioxin-like compounds as likely to be carcinogenic to
humans using the draft 1996 carcinogen risk assessment guidelines. EPA
is working on its final assessment for dioxin.\52\ An interagency
review group is evaluating EPA's designation of dioxin as a likely
human carcinogen. Reductions from today's nonroad proposal will have
minimal impact on overall dioxin emissions.
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\52\ U.S. EPA (June 2000) Exposure and Human Health Reassessment
of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds,
External Review Draft, EPA/600/P-00/001Ag. This material is
available electronically at http://www.epa.gov/ncea/dioxin.htm.
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3. Ozone
a. What Are the Health Effects of Ozone Pollution?
Ground-level ozone pollution (sometimes called ``smog'') is formed by
the reaction of volatile organic compounds (VOC) and nitrogen oxides
(NOX) in the atmosphere in the presence of heat and
sunlight. These two pollutants, often referred to as ozone precursors,
are emitted by many types of pollution sources, including on-road and
off-road motor vehicles and engines, power plants and industrial
facilities, and smaller ``area'' sources.
Ozone can irritate the respiratory system, causing coughing, throat
irritation, and/or uncomfortable sensation in the
chest.53 54 Ozone can reduce lung function and make it more
difficult to breathe deeply, and breathing may become more rapid and
shallow than normal, thereby limiting a person's normal activity. Ozone
also can aggravate asthma, leading to more asthma attacks that require
a doctor's attention and/or the use of additional medication. In
addition, ozone can inflame and damage the lining of the lungs, which
may lead to permanent changes in lung tissue, irreversible reductions
in lung function, and a lower quality of life if the inflammation
occurs repeatedly over a long time period (months, years, a lifetime).
People who are of particular concern with respect to ozone exposures
include children and adults who are active outdoors. Those people
particularly susceptible to ozone effects are people with respiratory
disease, such as asthma, and people with unusual sensitivity to ozone,
and children. Beyond its human health effects, ozone has been shown to
injure plants, which has the effect of reducing crop yields and
reducing productivity in forest ecosystems.55 56
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\53\ U.S. EPA (1996). Air Quality Criteria for Ozone and Related
Photochemical Oxidants, EPA/600/P-93/004aF. Docket No. A-99-06.
Document Nos. II-A-15 to 17.
\54\ U.S. EPA. (1996). Review of National Ambient Air Quality
Standards for Ozone, Assessment of Scientific and Technical
Information, OAQPS Staff Paper, EPA-452/R-96-007. Docket No. A-99-
06. Document No. II-A-22.
\55\ U.S. EPA (1996). Air Quality Criteria for Ozone and Related
Photochemical Oxidants, EPA/600/P-93/004aF. Docket No. A-99-06.
Document Nos. II-A-15 to 17.
\56\ U.S. EPA. (1996). Review of National Ambient Air Quality
Standards for Ozone, Assessment of Scientific and Technical
Information, OAQPS Staff Paper, EPA-452/R-96-007. Docket No. A-99-
06. Document No. II-A-22.
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The 8-hour ozone standard, established by EPA in 1997, is based on
well-documented science demonstrating that more people are experiencing
adverse health effects at lower levels of exertion, over longer
periods, and at lower ozone concentrations than addressed by the one-
hour ozone standard. (See, e.g., 62 FR 38861-62, July 18, 1997). The 8-
hour standard addresses ozone exposures of concern for the general
population and populations most at risk, including children active
outdoors, outdoor workers, and individuals with pre-existing
respiratory disease, such as asthma.
There has been new research that suggests additional serious health
effects beyond those that had been known when the 8-hour ozone health
standard was set. Since 1997, over 1,700 new health and welfare studies
relating to ozone have been published in peer-reviewed journals.\57\
Many of these studies have investigated the impact of ozone exposure on
such health effects as changes in lung structure and biochemistry,
inflammation of the
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lungs, exacerbation and causation of asthma, respiratory illness-
related school absence, hospital and emergency room visits for asthma
and other respiratory causes, and premature mortality. EPA is currently
in the process of evaluating these and other studies as part of the
ongoing review of the air quality criteria and NAAQS for ozone. A
revised Air Quality Criteria Document for Ozone and Other Photochemical
Oxidants will be prepared in consultation with EPA's Clean Air Science
Advisory Committee (CASAC). Key new health information falls into four
general areas: development of new-onset asthma, hospital admissions for
young children, school absence rate, and premature mortality.
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\57\ New Ozone Health and Environmental Effects References,
Published Since Completion of the Previous Ozone AQCD, National
Center for Environmental Assessment, Office of Research and
Development, U.S. Environmental Protection Agency, Research Triangle
Park, NC 27711 (7/2002) Docket No. A-2001-11. Document No. IV-A-19.
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Aggravation of existing asthma resulting from short-term ambient
ozone exposure was reported prior to the 1997 decision and has been
observed in studies published subsequently.58 59 In
particular, a relationship between long-term ambient ozone
concentrations and the incidence of new-onset asthma in adult males
(but not in females) was reported by McDonnell et al. (1999).\60\
Subsequently, an additional study suggests that incidence of new
diagnoses of asthma in children is associated with heavy exercise in
communities with high concentrations (i.e., mean 8-hour concentration
of 59.6 ppb) of ozone.\61\ This relationship was documented in children
who played 3 or more sports and thus had higher exposures and was not
documented in those children who played one or two sports. The larger
effect of high activity sports than low activity sports and an
independent effect of time spent outdoors also in the higher ozone
communities strengthened the inference that exposure to ozone may
modify the effect of sports on the development of asthma in some
children.
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\58\ Thurston, G.D., M.L. Lippman, M.B. Scott, and J.M. Fine.
1997. Summertime Haze Air Pollution and Children with Asthma.
American Journal of Respiratory Critical Care Medicine, 155: 654-
660.
\59\ Ostro, B, M. Lipsett, J. Mann, H. Braxton-Owens, and M.
White (2001) Air pollution and exacerbation of asthma in African-
American children in Los Angeles. Epidemiology 12(2): 200-208.
\60\ McDonnell, W.F., D.E. Abbey, N. Nishino and M.D. Lebowitz.
1999. ``Long-term ambient ozone concentration and the incidence of
asthma in nonsmoking adults: the ahsmog study.'' Environmental
Research. 80(2 Pt 1): 110-121.
\61\ McConnell, R.; Berhane, K.; Gilliland, F.; London, S.J.;
Islam, T.; Gauderman, W.J.; Avol, E.; Margolis, H.G.; Peters, J.M.
(2002) Asthma in exercising children exposed to ozone: a cohort
study. Lancet 359: 386-391.
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Previous studies have shown relationships between ozone and
hospital admissions in the general population. A study in Toronto
reported a significant relationship between 1-hour maximum ozone
concentrations and respiratory hospital admissions in children under
the age of two.\62\ Given the relative vulnerability of children in
this age category, we are particularly concerned about the findings.
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\62\ Burnett, R.T.; Smith--Doiron, M.; Stieb, D.; Raizenne,
M.E.; Brook, J.R.; Dales, R.E.; Leech, J.A.; Cakmak, S.; Krewski, D.
(2001) Association between ozone and hospitalization for acute
respiratory diseases in children less than 2 years of age. Am. J.
Epidemiol. 153: 444-452.
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Increased respiratory disease that are serious enough to cause
school absences have been associated with 1-hour daily maximum and 8-
hour average ozone concentrations in studies conducted in Nevada \63\
in kindergarten to 6th grade and in Southern California in grades 4
through 6.\64\ These studies suggest that higher ambient ozone levels
may result in increased school absenteeism.
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\63\ Chen, L.; Jennison, B.L.; Yang, W.; Omaye, S.T. (2000)
Elementary school absenteeism and air pollution. Inhalation Toxicol.
12: 997-1016.
\64\ Gilliland, FD, K Berhane, EB Rappaport, DC Thomas, E Avol,
WJ Gauderman, SJ London, HG Margolis, R McConnell, KT Islam, JM
Peters (2001) The effects of ambient air pollution on school
absenteeism due to respiratory illnesses Epidemiology 12:43-54.
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The air pollutant most clearly associated with premature mortality
is PM, with dozens of studies reporting such an association. However,
repeated ozone exposure is a possible contributing factor for premature
mortality, causing an inflammatory response in the lungs which may
predispose elderly and other sensitive individuals to become more
susceptible to other stressors, such as PM.65 66 67 Although
the findings have been mixed, the findings of three recent analyses
suggest that ozone exposure is associated with increased mortality.
Although the National Morbidity, Mortality, and Air Pollution Study
(NMMAPS) did not report an effect of ozone on total mortality across
the full year, the investigators who conducted the NMMAPS study did
observe an effect after limiting the analysis to summer when ozone
levels are highest.68 69 Similarly, other studies have shown
associations between ozone and mortality.70 71 Specifically,
Toulomi et al. (1997) found that 1-hour maximum ozone levels were
associated with daily numbers of deaths in 4 cities (London, Athens,
Barcelona, and Paris), and a quantitatively similar effect was found in
a group of four additional cities (Amsterdam, Basel, Geneva, and
Zurich).
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\65\ Samet JM, Zeger SL, Dominici F, Curriero F, Coursac I,
Dockery DW, Schwartz J, Zanobetti A. 2000. The National Morbidity,
Mortality and Air Pollution Study: Part II: Morbidity, Mortality and
Air Pollution in the United States. Research Report No. 94, Part II.
Health Effects Institute, Cambridge MA, June 2000. (Docket Number A-
2000-01, Document Nos. IV-A-208 and 209).
\66\ Devlin, R.B.; Folinsbee, L.J.; Biscardi, F.; Hatch, G.;
Becker, S.; Madden, M.C.; Robbins, M.; Koren, H. S. (1997)
Inflammation and cell damage induced by repeated exposure of humans
to ozone. Inhalation Toxicol. 9: 211-235.
\67\ Koren HS, Devlin RB, Graham DE, Mann R, McGee MP, Horstman
DH, Kozumbo WJ, Becker S, House DE, McDonnell SF, Bromberg, PA.
1989. Ozone-induced inflammation in the lower airways of human
subjects. Am. Rev. Respir. Dies. 139: 407-415.
\68\ Samet JM, Zeger SL, Dominici F, Curriero F, Coursac I,
Dockery DW, Schwartz J, Zanobetti A. 2000. The National Morbidity,
Mortality and Air Pollution Study: Part II: Morbidity, Mortality and
Air Pollution in the United States. Research Report No. 94, Part II.
Health Effects Institute, Cambridge MA, June 2000. (Docket Number A-
2000-01, Documents No. IV-A-208 and 209).
\69\ Samet JM, Zeger SL, Dominici F, Curriero F, Coursac I,
Zeger, S. Fine Particulate Air Pollution and Mortality in 20 U.S.
Cities, 1987--1994. The New England Journal of Medicine. Vol. 343,
No. 24, December 14, 2000. P. 1742-1749.
\70\ Thurston, G.D.; Ito, K. (2001) Epidemiological studies of
acute ozone exposures and mortality. J. Exposure Anal. Environ.
Epidemiol. 11: 286-294.
\71\ Touloumi, G.; Katsouyanni, K.; Zmirou, D.; Schwartz, J.;
Spix, C.; Ponce de Leon, A.; Tobias, A.; Quennel, P.; Rabczenko, D.;
Bacharova, L.; Bisanti, L.; Vonk, J.M.; Ponka, A. (1997) Short-term
effects of ambient oxidant exposure on mortality: a combined
analysis within the APHEA project. Am. J. Epidemiol. 146: 177-185.
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In all, the new studies that have become available since the 8-hour
ozone standard was adopted in 1997 continue to demonstrate the harmful
effects of ozone on public health, and the need to attain and maintain
the NAAQS.
b. Current and projected 8-hour ozone levels
As shown earlier (Figure II-1), unhealthy ozone concentrations
exceeding the level of the 8-hour standard (i.e., not requisite to
protect the public health with an adequate margin of safety) occur over
wide geographic areas, including most of the nation's major population
centers. These monitored areas include much of the eastern half of the
U.S. and large areas of California.
Based upon data from 1999-2001, there are 291 counties where 111
million people live that are measuring values that violate the 8-hour
ozone NAAQS.\72\ An additional 37 million people live in 155 counties
that have air quality measurements within 10 percent of the level of
the standard. These areas, though currently not violating the standard,
will also benefit from the additional emission reductions from this
rule.
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\72\ Additional counties may have levels above the NAAQS but do
not currently have monitors.
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From our air quality modeling for this proposal, we anticipate that
without emission reductions beyond those
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already required under promulgated regulation and approved SIPs, ozone
nonattainment will likely persist into the future. With reductions from
programs already in place, the number of counties violating the ozone
8-hour standard is expected to decrease in 2020 to 30 counties where 43
million people are projected to live. Thereafter, exposure to unhealthy
levels of ozone is expected to begin to increase again. In 2030 the
number of counties violating the ozone 8-hour NAAQS is projected to
increase to 32 counties where 47 million people are projected to live.
In addition, in 2030, 82 counties where 44 million people are projected
to live will be within 10 percent of violating the ozone 8-hour NAAQS.
EPA is still developing the implementation process for bringing the
nation's air into attainment with the ozone 8-hour NAAQS. EPA's current
plans call for designating ozone 8-hour nonattainment areas in April
2004. EPA is planning to propose that States submit SIPs that address
how areas will attain the 8-hour ozone standard within three years
after nonattainment designation regardless of their classification. EPA
is also planning to propose that certain SIP components, such as those
related to reasonably available control technology (RACT) and
reasonable further progress (RFP) be submitted within 2 years after
designation. We therefore anticipate that States will submit their
attainment demonstration SIPs by April 2007. Section 172(a)(2) of the
Clean Air Act requires that SIP revisions for areas that may be covered
only under subpart 1 of part D, title I of the Act demonstrate that the
nonattainment areas will attain the ozone 8-hour standard as
expeditiously as practicable but no later than five years from the date
that the area was designated nonattainment. However, based on the
severity of the air quality problem and the availability and
feasibility of control measures, the Administrator may extend the
attainment date ``for a period of no greater than 10 years from the
date of designation as nonattainment.'' Based on these provisions, we
expect that most or all areas covered under subpart 1 will attain the
ozone standard in the 2007 to 2014 time frame. For areas covered under
subpart 2, the maximum attainment dates provided under the Act range
from 3 to 20 years after designation, depending on an area's
classification. Thus, we anticipate that areas covered by subpart 2
will attain in the 2007 to 2014 time period.
Since the emission reductions expected from this proposal would
begin during the same time period, the projected reductions in nonroad
emissions would be extremely important to States in their effort to
meet the new NAAQS. It is our expectation that States will be relying
on such nonroad reductions in order to help them attain and maintain
the 8-hour NAAQS. Furthermore, since the nonroad emission reductions
will continue to grow in the years beyond 2014, they will also be
important for maintenance of the NAAQS for areas with attainment dates
of 2014 and earlier.
Using air quality modeling of the impacts of emission reductions,
we have made estimates of the change in future ozone levels that would
result from the proposed rule.\73\ That modeling shows that this rule
would produce nationwide air quality improvements in ozone levels. On a
population-weighted basis, the average change in future year design
values would be a decrease of 1.6 ppb in 2020, and 2.6 ppb in 2030.
Within areas predicted to violate the NAAQS in the projected base case,
the average decrease would be somewhat higher: 1.9 ppb in 2020 and 3.0
ppb in 2030.\74\
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\73\ These results are ozone changes projected for the
preliminary control option used for our modeling, as discussed in
the Draft RIA in section 3.6. The proposal differs from the modeled
control case based on updated information; however, we believe that
the net results would approximate future emissions, although we
anticipate the ozone changes might be slightly different.
\74\ This is in spite of the fact that NOX reductions
can at certain times in some areas cause ozone levels to increase.
Such ``disbenefits'' are predicted in our modeling, but these
results make clear that the overall effect of the proposed rule is
positive. See the draft RIA for more information.
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The model predictions of whether specific counties will violate the
NAAQS or not is uncertain, especially for counties with design values
falling very close to the standard. This makes us more confident in our
prediction of average air quality changes than in our prediction of the
exact numbers of counties projected as exceeding the NAAQS.
Furthermore, actions by States to meet their SIP obligations will
change the number of counties violating the NAAQS in the time frame we
are modeling for this rule. If State actions resulted in an increase in
the number of areas that are very close to, but still above, the NAAQS,
then this rule might bring many of those counties down sufficiently to
eliminate remaining violations. In addition, if State actions brought
several counties we project to be very close to the standard in the
future down sufficiently to eliminate violations, then the air quality
improvements from this proposal might serve more to assist these areas
in maintaining the standards than in changing their status. Bearing
this in mind, our modeling indicates that, out of 32 counties predicted
to violate the NAAQS, the proposal would reduce the number of violating
counties by 2 in 2020 and by 4 in 2030, without consideration of new
State or Federal programs.
C. Other Environmental Effects
The following section presents information on five categories of
public welfare and environmental impacts related to nonroad heavy-duty
vehicle emissions: visibility impairment, acid deposition,
eutrophication of water bodies, plant damage from ozone, and water
pollution resulting from deposition of toxic air pollutants with
resulting effects on fish and wildlife.
1. Visibility
a. Visibility is Impaired by Fine PM and Precursor Emissions From
Nonroad Engines Subject to this Proposed Rule
Visibility can be defined as the degree to which the atmosphere is
transparent to visible light.\75\ Fine particles with significant
light-extinction efficiencies include organic matter, sulfates,
nitrates, elemental carbon (soot), and soil. Size and chemical
composition of particles strongly affects their ability to scatter or
absorb light. Sulfates contribute to visibility impairment especially
on the haziest days across the U.S., accounting in the rural Eastern
U.S. for more than 60 percent of annual average light extinction on the
best days and up to 86 percent of average light extinction on the
haziest days. Nitrates and elemental carbon each typically contribute 1
to 6 percent of average light extinction on haziest days in rural
Eastern U.S. locations.\76\
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\75\ National Research Council, 1993. Protecting Visibility in
National Parks and Wilderness Areas. National Academy of Sciences
Committee on Haze in National Parks and Wilderness Areas. National
Academy Press, Washington, DC. This document is available on the
Internet at http://www.nap.edu/books/0309048443/html/. See also U.S.
EPA Air Quality Criteria Document for Particulate Matter (1996)
(available on the Internet at http://cfpub.epa.gov/ncea/cfm/
partmatt.cfm) and Review of the National Ambient Air Quality
Standards for Particulate Matter: Policy Assessment of Scientific
and Technical Information. These documents can be found in Docket A-
99-06, Documents No. II-A-23 and IV-A-130-32.
\76\ U.S. EPA Trends Report 2001. This document is available on
the Internet at http://www.epa.gov/airtrends/.
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Visibility is important because it directly affects people's
enjoyment of daily activities in all parts of the country. Individuals
value good visibility for the well-being it provides them directly,
both in where they live and work, and in places where they enjoy
recreational opportunities.
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Visibility is also highly valued in significant natural areas such as
national parks and wilderness areas, because of the special emphasis
given to protecting these lands now and for future generations.
To quantify changes in visibility, we compute a light-extinction
coefficient, which shows the total fraction of light that is decreased
per unit distance. Visibility can be described in terms of visual range
or light extinction and is reported using an indicator called
deciview.\77\ In addition to limiting the distance that one can see,
the scattering and absorption of light caused by air pollution can also
degrade the color, clarity, and contrast of scenes.
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\77\ Visual range can be defined as the maximum distance at
which one can identify a black object against the horizon sky. It is
typically described in miles or kilometers. Light extinction is the
sum of light scattering and absorption by particles and gases in the
atmosphere. It is typically expressed in terms of inverse megameters
(Mm-1), with larger values representing worse visibility.
The deciview metric describes perc
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