[Federal Register: January 18, 2001 (Volume 66, Number 12)] [Rules and Regulations] [Page 5001-5050] From the Federal Register Online via GPO Access [wais.access.gpo.gov] [DOCID:fr18ja01-16] [[Page 5001]] ----------------------------------------------------------------------- Part V Environmental Protection Agency ----------------------------------------------------------------------- 40 CFR Parts 69, 80, and 86 Control of Air Pollution From New Motor Vehicles: Heavy-Duty Engine and Vehicle Standards and Highway Diesel Fuel Sulfur Control Requirements; Final Rule [[Page 5002]] ----------------------------------------------------------------------- ENVIRONMENTAL PROTECTION AGENCY 40 CFR Parts 69, 80, and 86 [AMS-FRL-6923-7] RIN 2060-AI69 Control of Air Pollution from New Motor Vehicles: Heavy-Duty Engine and Vehicle Standards and Highway Diesel Fuel Sulfur Control Requirements AGENCY: Environmental Protection Agency. ACTION: Final rule. ----------------------------------------------------------------------- SUMMARY: The pollution emitted by diesel engines contributes greatly to our nation's continuing air quality problems. Even with more stringent heavy-duty highway engine standards set to take effect in 2004, these engines will continue to emit large amounts of nitrogen oxides and particulate matter, both 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. Numerous studies also link diesel exhaust to increased incidence of lung cancer. We believe that diesel exhaust is likely to be carcinogenic to humans by inhalation and that this cancer hazard exists for occupational and environmental levels of exposure. We are establishing a comprehensive national control program that will regulate the heavy-duty vehicle and its fuel as a single system. As part of this program, new emission standards will begin to take effect in model year 2007, and will apply to heavy-duty highway engines and vehicles. These standards are based on the use of high-efficiency catalytic exhaust emission control devices or comparably effective advanced technologies. Because these devices are damaged by sulfur, we are also reducing the level of sulfur in highway diesel fuel significantly by mid-2006. The program provides substantial flexibility for refiners, especially small refiners, and for manufacturers of engines and vehicles. These options will ensure that there is widespread availability and supply of the low sulfur diesel fuel from the very beginning of the program, and will provide engine manufacturers with the lead time needed to efficiently phase-in the exhaust emission control technology that will be used to achieve the emissions benefits of the new standards. We estimate that heavy-duty trucks and buses today account for about one-third of nitrogen oxides emissions and one-quarter of particulate matter emissions from mobile sources. In some urban areas, the contribution is even greater. This program will reduce particulate matter and oxides of nitrogen emissions from heavy duty engines by 90 percent and 95 percent below current standard levels, respectively. In order to meet these more stringent standards for diesel engines, the program calls for a 97 percent reduction in the sulfur content of diesel fuel. As a result, diesel vehicles will achieve gasoline-like exhaust emission levels. We are also finalizing more stringent standards for heavy-duty gasoline vehicles, based in part on the use of the low sulfur gasoline that will be available when the standards go into effect. The clean air impact of this program will be dramatic when fully implemented. By 2030, this program will reduce annual emissions of nitrogen oxides, nonmethane hydrocarbons, and particulate matter by a projected 2.6 million, 115,000 and 109,000 tons, respectively. We project that these reductions and the resulting significant environmental benefits of this program will come at an average cost increase of about $2,000 to $3,200 per new vehicle in the near term and about $1,200 to $1,900 per new vehicle in the long term, depending on the vehicle size. In comparison, new vehicle prices today can range well over $100,000 for larger heavy-duty vehicles. We estimate that when fully implemented the sulfur reduction requirement will increase the cost of producing and distributing diesel fuel by about five cents per gallon. DATES: This rule will become effective March 19, 2001. The incorporation by reference of certain publications listed in this rule is approved by the Director of the Office of Federal Register as of March 19, 2001. ADDRESSES: Comments: All comments and materials relevant to today's action have been placed in Public Docket No. A-99-06 at the following address: U.S. Environmental Protection Agency (EPA), Air Docket (6102), Room M-1500, 401 M Street, SW, Washington, DC 20460 (on the ground floor in Waterside Mall) from 8:00 a.m. to 5:30 p.m., Monday through Friday, except on government holidays. You can reach the Air Docket by telephone at (202) 260-7548 and by facsimile at (202) 260-4400. We may charge a reasonable fee for copying docket materials, as provided in 40 CFR part 2. FOR FURTHER INFORMATION CONTACT: Margaret Borushko, U.S. EPA, National Vehicle and Fuel Emissions Laboratory, 2000 Traverwood, Ann Arbor MI 48105; Telephone (734) 214-4334, FAX (734) 214-4816, E-mail borushko.margaret@epa.gov SUPPLEMENTARY INFORMATION: Regulated Entities This action will affect you if you produce or import new heavy-duty engines which are intended for use in highway vehicles such as trucks and buses, or produce or import such highway vehicles, or convert heavy-duty vehicles or heavy-duty engines used in highway vehicles to use alternative fuels, or produce or import light-duty highway diesel vehicles. It will also affect you if you produce, import, distribute, or sell highway 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 69, 80, and 86. If you have questions, call the person listed in the FOR FURTHER INFORMATION CONTACT section of this preamble: ---------------------------------------------------------------------------------------------------------------- NAICS Category Codes a SIC Codes Examples of potentially regulated entities ----------------------------------------------------b----------------------------------------------------------- Industry........................ 336112 3711 Engine and Truck Manufacturers 336120 Industry........................ 811112 7533 Commercial Importers of Vehicles and 811198 7549 Vehicle Components Industry........................ 324110 2911 Petroleum Refiners Industry........................ 422710 5171 Diesel Fuel Marketers and Distributors 422720 5172 industry........................ 484220 4212 Diesel Fuel Carriers [[Page 5003]] 484230 4213 ---------------------------------------------------------------------------------------------------------------- a North American Industry Classifications System (NAICS). b Standard Industrial Classification (SIC) system code. Access to Rulemaking Documents Through the Internet Today's final rule is available electronically on the day of publication from the Environmental Protection Agency Internet Web site listed below. Electronic copies of the preamble, regulatory language, Regulatory Impact Analysis, and other documents associated with today's final rule are available from the EPA Office of Transportation and Air Quality (formerly the Office of Mobile Sources) Web site listed below shortly after the rule is signed by the Administrator. This service is free of charge, except any cost that you incur for connecting to the Internet. Environmental Protection Agency Web Site: http://www.epa.gov/ fedrgstr/ (Either select a desired date or use the Search feature.) Office of Transportation and Air Quality (OTAQ) Web Site: http:// www.epa.gov/otaq/ (Look in ``What's New'' or under the ``Heavy Trucks/ Busses'' topic.) Please note that due to differences between the software used to develop the document and the software into which document may be downloaded, changes in format, page length, etc. may occur. Table of Contents I. Overview A. What Requirements Are Being Set? 1. Heavy-Duty Emission Standards 2. Fuel Quality Standards B. Why is EPA Taking This Action? 1. Heavy-Duty Vehicles Contribute to Serious Air Pollution Problems 2. Technology-Based Solutions 3. Basis for Action Under the Clean Air Act C. Putting This Rule in Perspective 1. Diesel Popularity 2. Past Progress and New Developments 3. Tier 2 Emissions Standards 4. Mobile Source Air Toxics Rulemaking 5. Nonroad Engine Standards and Fuel 6. State Initiatives 7. Retrofit Programs 8. Actions in Other Countries II. The Air Quality Need and Projected Benefits A. Overview B. Public Health and Welfare Concerns 1. Health and Welfare Concerns Raised During Public Hearings 2. Ozone and its Precursors a. Health and Welfare Effects From Short-Term Exposures to Ozone b. Current and Future Nonattainment Status With the 1-Hour Ozone NAAQS c. Public Health and Welfare Concerns from Prolonged and Repeated Exposures to Ozone 3. Particulate Matter a. Health and Welfare Effects b. Attainment and Maintenance of the PM10 NAAQS c. Public Health and Welfare Concerns from Exposure to Fine PM d. Other Welfare Effects Associated with PM e. Conclusions Regarding PM 4. Diesel Exhaust a. Potential Cancer Effects of Diesel Exhaust b. Noncancer Effects of Diesel Exhaust 5. Other Criteria Pollutants 6. Other Air Toxics a. Benzene b. 1,3-Butadiene c. Formaldehyde d. Acetaldehyde e. Acrolein f. Dioxins 7. Other Welfare and Environmental Effects a. Acid Deposition b. Eutrophication and Nitrification c. Polycyclic Organic Matter Deposition d. Visibility and Regional Haze C. Contribution From Heavy-Duty Vehicles 1. NOX Emissions 2. PM Emissions 3. Environmental Justice D. Anticipated Emissions Benefits 1. NOX Reductions 2. PM Reductions 3. NMHC Reductions 4. Additional Emissions Benefits a. CO Reductions b. SOX Reductions c. Air Toxics Reductions E. Clean Heavy-Duty Vehicles and Low-Sulfur Diesel Fuel are Critically Important for Improving Human Health and Welfare III. Heavy-Duty Engine and Vehicle Standards A. Why Are We Setting New Heavy-Duty Standards? B. Emission Control Technologies for Heavy-Duty Vehicles and Engines C. What Engine and Vehicle Standards are We Finalizing? 1. Heavy-Duty Engine Exhaust Emissions Standards a. FTP Standards b. Supplemental Provisions for HD Diesel Engines (SET & NTE) c. Crankcase Emissions Control d. On-Board Diagnostics (OBD) 2. Heavy-Duty Vehicle Exhaust Emissions Standards a. FTP Standards b. Supplemental Federal Test Procedure c. On-Board Diagnostics (OBD) 3. Heavy-Duty Evaporative Emission Standards D. Incentives for Early Introduction of Clean Engines and Vehicles E. Feasibility of the New Engine and Vehicle Standards 1. Feasibility of Stringent Standards for Heavy-Duty Diesel a. Meeting the PM Standard b. Meeting the NOX Standard c. Meeting the NMHC Standard d. Meeting the Crankcase Emissions Requirements e. The Complete System 2. Feasibility of Stringent Standards for Heavy-Duty Gasoline 3. Feasibility of the New Evaporative Emission Standards F. Need for Low Sulfur Diesel Fuel 1. Catalyzed Diesel Particulate Filters and the Need for Low Sulfur Fuel a. Inhibition of Trap Regeneration Due to Sulfur b. Loss of PM Control Effectiveness c. Increased Maintenance Cost for Diesel Particulate Filters Due to Sulfur 2. Diesel NOX 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 3. What About Sulfur in Engine Lubricating Oils? G. Fuel Economy Impact of High Efficiency Control Technologies 1. Diesel Particulate Filters and Fuel Economy 2. NOX Control Technologies and Fuel Economy 3. Emission Control Systems for 2007 and Net Fuel Economy Impacts H. Review of the Status of Heavy-Duty Diesel NOX Emission Control Technology IV. Our Program for Controlling Highway Diesel Sulfur A. Highway Diesel Sulfur Standards for Refiners and Importers 1. Standards and Deadlines that Refiners and Importers Must Meet 2. Temporary Compliance Option for Refiners and Importers a. Generating Credits b. Using Credits c. How Long Will Credits Last? d. Additional Limitations on Credit Trading for Some States 3. What Information Must Refiners/Importers Submit to Us? 4. Impacts of the Highway Diesel Fuel Program a. Ensures Adequate Supplies of Highway Diesel Fuel b. Ensures Widespread Availability of Low Sulfur Diesel Fuel c. Provides Lower Costs to Refineries d. Misfueling Concerns Should Be Minimized [[Page 5004]] e. Summary B. What Provisions Apply in the Geographic Phase-in Area? 1. What Is the Geographic Phase-in Area and How Was it Established? 2. Highway Diesel Provisions for GPA Refiners 3. How Do Refiners Apply for an Extension of the GPA Gasoline Program? 4. Required Reporting for GPA Refiners C. Hardship Provisions for Qualifying Refiners 1. Hardship Provisions for Qualifying Small Refiners a. Qualifying Small Refiners b. How Do We Define Small Refiners? c. What Options Are Available for Small Refiners? d. How Do Small Refiners Apply for Small Refiner Status? 2. Farmer Cooperative Refiners Will Benefit From the Flexible Provisions Available to Other Refiners 3. General Hardship Provisions a. Temporary Waivers from Low Sulfur Diesel Requirements in Extreme Unforseen Circumstances b. Temporary Waivers Based on Extreme Hardship Circumstances D. Technological Feasibility of the Low Sulfur Diesel Fuel Program 1. What Technology Will Refiners Use? 2. Have These Technologies Been Commercially Demonstrated? 3. Feasibility of Distributing Low Sulfur Highway Diesel Fuel E. What Are the Potential Impacts of the Low Sulfur Diesel Program on Lubricity and Other Fuel Properties? 1. What Is Lubricity and Why Might It Be a Concern? 2. Today's Action on Lubricity: a Voluntary Approach 3. What Are Today's Actions on Fuel Properties Other than Sulfur? F. How Are State Programs Affected by the Low Sulfur Diesel Program? 1. State Preemption 2. What Provisions Apply in Alaska? a. Today's Action Regarding the 500 ppm Standard in Alaska b. Why Are We Treating Alaska Uniquely? 3. What Provisions Apply in American Samoa, Guam, and the Commonwealth of Northern Mariana Islands? a. Today's Action Regarding the Highway Diesel Fuel Standard in the Territories b. Why Are We Treating These Territories Uniquely? G. Refinery Air Permitting V. Economic Impact A. Cost for Diesel Vehicles to Meet Emissions Standards 1. Summary of New System and Operating Costs 2. New System Costs for NOX and PM Emission Control 3. Operating Costs Associated With NOX and PM Control B. Cost for Gasoline Vehicles to Meet the New Emissions Standards 1. Summary of New System Costs 2. Operating Costs Associated With Meeting the Heavy-Duty Gasoline Standard C. Cost of Fuel Change 1. Refinery Costs 2. Highway Diesel Fuel Supply 3. Cost of Lubricity Additives 4. Distribution Costs a. Distribution Costs Under the Fully Implemented Program b. Distribution Costs During the Initial Years 5. Benefits of Low-sulfur Diesel Fuel for the Existing Diesel Fleet D. Aggregate Costs E. Cost Effectiveness 1. What Is the Cost Effectiveness of This Program? 2. Comparison With Other Means of Reducing Emissions F. Does the Value of the Benefits Outweigh the Cost of the Standards? 1. What Was Our Overall Approach to the Benefit-Cost Analysis? 2. What Are the Significant Limitations of the Benefit-Cost Analysis? 3. How Has the Benefit-Cost Analysis Changed from Proposal? 4. What Are the Benefits in the Years Leading up to 2030? 5. What Were the Results of the Benefit-Cost Analysis? VI. Requirements for Engine and Vehicle Manufacturers A. Compliance with Standards and Enforcement 1. Allowable Maintenance 2. Emission Data Waivers 3. Crankcase Emissions 4. Non-Conformance Penalties 5. Idle CO Standards B. Compliance With Phase-in Schedules C. Averaging, Banking, and Trading D. FTP Changes to Accommodate Regeneration of Exhaust Emission Controls E. Improvements to the Test Procedures F. Certification Fuel G. Misfueling Concerns for Light-and Heavy-duty Diesel Vehicles H. In-Use Compliance Levels During the Transition Years to New Technologies VII. Highway Diesel Fuel Program: Compliance, Enforcement and Downstream Provisions A. General Provisions 1. Definition of Diesel Fuel Covered by This Program 2. Relationship to Highway Diesel Standards B. What Are the Requirements for Refiners and Importers? 1. General Requirements 2. Refiner and Importer Temporary Compliance Option Provisions and the Credit Trading Program a. Early Credits Program b. Credit Use in a Credit Deficit Situation c. Resolving Issues of Invalid Credits d. Compliance Provisions e. Additional Provisions for Importers of Diesel Fuel and for Foreign Refiners Subject to the Temporary Compliance Option and Hardship Provisions 3. Refiner Hardship Provisions a. General Refiner Hardship Provisions b. Small Refiner Hardship Provisions c. Relief for Refiners Supplying Gasoline to the Tier 2 Geographic Phase-In Area (GPA) C. What Requirements Apply Downstream of the Refinery or Import Facility? 1. Downstream Enforcement of the Standards 2. Other Provisions a. Implementation Dates b. Product Segregation and Contamination c. Diesel Fuel Pump Labeling 3. Use of Used Motor Oil in New Diesel Vehicles 4. Use of Kerosene in Diesel Fuel 5. Use of Diesel Fuel Additives D. What Are the Testing and Sampling Methods and Requirements? 1. Diesel Fuel Testing Requirements and Test Methods 2. Diesel Fuel Sampling Methods E. What Are the Recordkeeping, Reporting and Product Transfer Document Requirements? 1. Registration of Refiners and Importers a. All Refiners and Importers b. Prospective Small Refiners c. Refiners Seeking an Extension of the GPA Gasoline Sulfur Standards 2. Pre-Compliance Reports a. All Refiners b. Small Refiners c. GPA Refiners 3. Annual Compliance Reports a. All Refiners b. Small Refiners 4. Initial Confirmation of 15 ppm Fuel Production 5. Product Transfer Documents (PTDs) a. Diesel Fuel b. Additives 6. Recordkeeping Requirements 7. Record Retention F. Are There Any Exemptions From the Highway Diesel Fuel Requirements? 1. Research and Development 2. Racing Vehicles 3. Military Fuel G. Liability and Penalty Provisions for Noncompliance 1. General 2. What Is the Liability That Additive Manufacturers and Distributors, and Parties That Blend Additives into Diesel Fuel, Are Subject To? 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 Will Compliance With the Sulfur Standards Be Determined? VIII.Standards and Fuel for Nonroad Diesel Engines IX. Public Participation X. Administrative Requirements A. Administrative Designation and Regulatory Analysis B. Regulatory Flexibility Analysis 1. Need for and Objectives of the Rule 2. Summary of Significant Public Comments on the IRFA 3. Types and Number of Small Entities 4. Reporting, Recordkeeping and Other Compliance Requirements 5. Regulatory Alternatives To Minimize Impact on Small Entities C. Paperwork Reduction Act [[Page 5005]] D. Intergovernmental Relations 1. Unfunded Mandates Reform Act 2. Executive Order 13084: Consultation and Coordination with Indian Tribal Governments E. National Technology Transfer and Advancement Act F. Executive Order 13045: Children's Health Protection G. Executive Order 13132: Federalism H. Congressional Review Act XI. Statutory Provisions and Legal Authority I. Overview This rule covers the second of two phases in a comprehensive nationwide program for controlling emissions from heavy-duty engines (HDEs) and vehicles. It builds upon the phase 1 program we recently finalized (65 FR 59896, October 6, 2000). That action affirmed the 50 percent reduction in emissions of oxides of nitrogen ( NOX) from 2004 model year highway diesel engines, set in 1997 (62 FR 54693, October 21, 1997), and set new emission standards for heavy-duty gasoline-fueled engines and vehicles for 2005. This second phase of the program looks beyond 2004, based on the use of high-efficiency exhaust emission control devices and the consideration of the vehicle and its fuel as a single system. In developing this rule, we took into consideration comments received in response to the advance notice of proposed rulemaking (64 FR 26142, May 13, 1999) and the notice of proposed rulemaking (NPRM) (65 FR 35430, June 2, 2000), including comments provided at five public hearings last June. This program will result in particulate matter (PM) and NOX emission levels that are 90 percent and 95 percent below the standard levels in effect today, respectively. In order to meet these more stringent standards for diesel engines, the rule mandates a 97 percent reduction in the sulfur content of diesel fuel. The heavy- duty engine standards will be effective starting in the 2007 model year and the low sulfur diesel fuel needed to facilitate the standards will be widely available in September 2006. As a result, diesel vehicles will achieve gasoline-like exhaust emission levels, in addition to their inherent advantages over gasoline vehicles with respect to fuel economy, lower greenhouse gas emissions, and lower evaporative hydrocarbon emissions. The rule also includes more stringent standards for heavy-duty gasoline vehicles. In addition to its impact on heavy- duty vehicle emissions, this rule will make clean diesel fuel available in time for implementation of the light-duty Tier 2 standards. The standards will result in substantial benefits to public health and welfare and the environment through significant reductions in emissions of NOX, PM, nonmethane hydrocarbons (NMHC), carbon monoxide (CO), sulfur oxides (SOX), and air toxics. We project that by 2030, this phase 2 program will reduce annual emissions of NOX, NMHC, and PM by 2.6 million, 115,000 and 109,000 tons, respectively. These emission reductions will prevent 8,300 premature deaths, over 9,500 hospitalizations, and 1.5 million work days lost. All told the benefits of this rule equal $70.3 billion. A sizeable part of the benefits in the early years of this program come from large reductions in the amount of direct and secondary PM caused by the existing fleet of heavy-duty vehicles. These reductions are due to the use of the higher quality diesel fuel in these vehicles. A. What Requirements Are Being Set? There are two basic parts to this program: (1) New exhaust emission standards for heavy-duty highway engines and vehicles, and (2) new quality standards for highway 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. The feasibility of the emission standards is based on the use of high-efficiency exhaust emission control devices that would be damaged by sulfur in the fuel. This rule, by providing extremely low sulfur diesel fuel, will also enable cleaner diesel passenger vehicles and light-duty trucks. This is because the same pool of highway diesel fuel also services these light-duty diesel vehicles, and these vehicles can employ technologies similar to the high-efficiency heavy-duty exhaust emission control technologies that will be enabled by the fuel change. We believe these technologies are needed for diesel vehicles to comply with our Tier 2 emissions standards for light-duty highway vehicles (65 FR 6698, February 10, 2000). We believe that this systems approach is a comprehensive way to enable effective new technologies for clean diesel, affecting all sizes of highway diesel engines, and may translate to future reductions from diesel engines used in nonroad applications too. The fuel change, in addition to enabling new technologies, will also produce emissions and maintenance benefits in the existing fleet of highway diesel vehicles. These benefits will include reduced sulfate PM and sulfur oxides emissions, reduced engine wear and less frequent oil changes, and longer-lasting exhaust gas recirculation (EGR) components on engines equipped with EGR. Heavy-duty gasoline vehicles will also be expected to have much lower emissions due to the transfer of recent technology developments for light-duty applications, and the recent action taken to reduce sulfur in gasoline as part of the Tier 2 rule. The basic elements of the rule are outlined below. Detailed provisions and justifications for our rule are discussed in subsequent sections. 1. Heavy-Duty Emission Standards We are finalizing a PM emissions standard for new heavy-duty engines of 0.01 grams per brake-horsepower-hour (g/bhp-hr), to take full effect for diesels in the 2007 model year.1 We are also finalizing standards for NOX and NMHC of 0.20 g/bhp-hr and 0.14 g/bhp-hr, respectively. These NOX and NMHC standards will be phased in together between 2007 and 2010, for diesel engines. The phase-in will be on a percent-of-sales basis: 50 percent from 2007 to 2009 and 100 percent in 2010. This phase-in schedule differs somewhat from the proposed schedule for reasons explained in Section III. Gasoline engines will be subject to these standards based on a phase-in requiring 50 percent compliance in the 2008 model year and 100 percent compliance in the 2009 model year. This phase-in schedule also differs from that proposed for reasons explained in Section III. In addition, we are finalizing our proposal to include turbocharged diesels in the existing crankcase emissions prohibition, effective in 2007. --------------------------------------------------------------------------- \1\ Note that throughout this preamble we refer to diesel and gasoline vehicles and engines. We tend to use those terms given the preponderance of vehicles using diesel fuel or gasoline fuel in the U.S. heavy-duty highway market. However, when we refer to a diesel engine, we generally mean any engine using the diesel cycle. When we refer to a gasoline engine or vehicle, we generally mean any Otto- cycle vehicle or engine. Therefore, the emission standards discussed throughout this preamble apply equally to engines and vehicles fueled by alternative fuels, unless otherwise specified in the regulatory text accompanying today's rule. --------------------------------------------------------------------------- Standards for complete HDVs will be implemented on the same schedule as for gasoline engine standards. For certification of complete vehicles between 8500 and 10,000 pounds gross vehicle weight rating (GVWR), the standards are 0.2 grams per mile (g/mi) for NOX, 0.02 g/mi for PM, 0.195 g/mi for NMHC, and 0.032 g/mi for formaldehyde.2 For vehicles between [[Page 5006]] 10,000 and 14,000 pounds, the standards are 0.4 g/mi for NOX, 0.02 g/mi for PM, 0.230 g/mi for NMHC, and 0.040 g/mi for formaldehyde. These standards levels are roughly comparable to the engine-based standards in these size ranges. Note that these standards will not apply to vehicles above 8500 pounds that we classify as medium-duty passenger vehicles as part of our Tier 2 program. --------------------------------------------------------------------------- \2\ Vehicle weight ratings in this rule refer to GVWR (the curb weight of the vehicle plus its maximum recommended load of passengers and cargo) unless noted otherwise. --------------------------------------------------------------------------- Finally, we are adopting new evaporative emissions standards for heavy-duty engines and vehicles, effective on the same schedule as the gasoline engine and vehicle exhaust emission standards. The new standards for 8500 to 14,000 pound vehicles are 1.4 and 1.75 grams per test for the 3-day diurnal and supplemental 2-day diurnal tests, respectively. Standards levels of 1.9 and 2.3 grams per test will apply for vehicles over 14,000 pounds. These standards represent more than a 50 percent reduction in the numerical standards as they exist today. The program includes flexibility provisions to facilitate the transition to the new standards and to encourage the early introduction of clean technologies, and adjustments to various testing and compliance requirements to address differences between the new technologies and existing engine-based technologies. These provisions are described in Sections III and VI. 2. Fuel Quality Standards This rule specifies that, beginning June 1, 2006, refiners must begin producing highway diesel fuel that meets a maximum sulfur standard of 15 parts per million (ppm). All 2007 and later model year diesel-fueled vehicles must be refueled with this new 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 low sulfur fuel production and distribution. Today's program includes a combination of flexibilities available to refiners to ensure a smooth transition to low sulfur highway diesel fuel. First, refiners can take advantage of a temporary compliance option, including an averaging, banking and trading component, beginning in June 2006 and lasting through 2009, with credit given for early compliance before June 2006. Under this temporary compliance option, up to 20 percent of highway diesel fuel may continue to be produced at the existing 500 ppm sulfur maximum standard. Highway diesel fuel marketed as complying with the 500 ppm sulfur standard must be segregated from 15 ppm fuel in the distribution system, and may only be used in pre-2007 model year heavy-duty vehicles. Second, we are providing additional hardship provisions for small refiners to minimize their economic burden in complying with the 15 ppm sulfur standard. Third, we are providing additional flexibility to refiners subject to the Geographic Phase-in Area (GPA) provisions of the Tier 2 gasoline sulfur program, which will allow them the option of staggering their gasoline and diesel investments. Finally, we are adopting a general hardship provision for which any refiner may apply on a case-by-case basis under certain conditions. These hardship provisions, coupled with the temporary compliance option, will provide a ``safety valve'' allowing up to 25 percent of highway diesel fuel produced to remain at 500 ppm for these transitional years to minimize any potential for highway diesel fuel supply problems. In addition, today's program includes unique provisions for implementing the low sulfur diesel fuel program in the State of Alaska, given that it is exempt from the current 500 ppm standard. Certain U.S. territories are excluded from both the new engine standards and highway diesel fuel standards. The compliance provisions for ensuring diesel fuel quality are essentially consistent with those that have been in effect since 1993 under the existing 500 ppm sulfur standard (55 FR 34120, August 21, 1990). Additional compliance provisions have been established primarily during the transition years of the program to verify refiners' compliance with the temporary compliance option to ensure the two grades of highway diesel fuel remain segregated, and to discourage misfueling of model year 2007 and later diesel vehicles. B. Why is EPA Taking This Action? 1. Heavy-Duty Vehicles Contribute to Serious Air Pollution Problems As discussed in detail in Section II, emissions from heavy-duty vehicles contribute greatly to a number of serious air pollution problems, and would have continued to do so into the future absent further controls to reduce these emissions. First, heavy-duty vehicles contribute to the health and welfare effects of 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. Ozone also causes crop and forestry losses, and PM causes damage to materials and soiling of commonly used building materials and culturally important items such as statues and works of art. Second, NOX, SOX and PM contribute to substantial visibility impairment in many parts of the U.S. Third, NOX emissions from heavy-duty trucks contribute to the acidification, nitrification and eutrophication of water bodies. Fourth, the Agency has concluded, and the Clean Air Scientific Advisory Committee has approved in public session, that diesel exhaust is likely to be carcinogenic to humans. Millions of Americans live in areas with unhealthful air quality that currently endangers public health and welfare. Without emission reductions from the standards for heavy-duty vehicles, there is a significant risk that an appreciable number of 45 areas with 128 million people across the country will violate the 1-hour ozone national ambient air quality standard (NAAQS) during the period when these standards will take effect. Furthermore, our analysis shows that PM10 concentrations in 10 areas with a population of 28 million people face a significant risk of exceeding the PM10 NAAQS without significant additional controls between 2007 and 2030. Under the mandates and authorities in the Clean Air Act, Federal, state, and local governments are working to bring ozone and particulate levels into compliance with the 1-hour ozone and PM10 NAAQS through State Implementation Plan (SIP) attainment and maintenance plans, and to ensure that future air quality reaches and continues to achieve these health-based standards. The reductions in this 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 ozone and fine PM at concentrations that do not constitute a violation of the 1-hour ozone and PM10 NAAQS. Emissions from heavy-duty vehicles account for substantial portions of the country's ambient PM and NOX levels. ( NOX is a key precursor to ozone formation). By 2007, we estimate that heavy-duty vehicles will account for 28 percent of mobile source NOX emissions and 20 percent of mobile source PM emissions. These proportions are even [[Page 5007]] higher in some urban areas, such as in Sacramento, Atlanta, and Washington, DC, where HDVs contribute over 34 percent of the mobile source NOX emissions, and in Santa Fe, Los Angeles, and Hartford, where heavy-duty vehicle PM emissions account for 38, 25 and 30 percent of the mobile source PM emissions inventory, respectively. Over time, the relative contribution of diesel engines to air quality problems will go even higher if diesel-equipped light-duty vehicles become more popular, as is expected by some automobile manufacturers. The PM and NOX standards for heavy-duty vehicles in this rule will have a substantial impact on emissions. By 2030, NOX emissions from heavy-duty vehicles under today's standards will be reduced by 2.6 million tons, and PM emissions will decline by about 109,000 tons, dramatically reducing this source of NOX and PM emissions. Urban areas, which include many poorer neighborhoods, can be disproportionately impacted by HDV emissions, and these neighborhoods will thus receive a relatively larger portion of the benefits expected from new HDV emissions controls. In addition to its contribution to PM inventories, diesel exhaust PM is of special concern because it has been implicated in an increased risk of lung cancer and respiratory disease. The EPA draft Health Assessment Document for Diesel Exhaust (Draft Assessment) was reviewed in public session by the Clean Air Scientific Advisory Committee (CASAC) on October 12-13, 2000.3 The Agency has concluded, and the CASAC approved at this session, that diesel exhaust is likely to be carcinogenic to humans. 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.4 --------------------------------------------------------------------------- \3\ EPA (2000) Review of EPA's Health Assessment Document for Diesel Exhaust (EPA 600/8-90/057E). Review by the Clean Air Scientific Advisory Committee (CASAC) December 2000. EPA-SAB-CASAC- 01-003. \4\ For example, see letter dated July 13, 1999 from John Elston and Richard Baldwin on behalf of the State and Territorial Air Pollution Program Administrators and the Association of Local Air Pollution Control Officials (docket A-99-06, item II-D-78). --------------------------------------------------------------------------- 2. Technology-Based Solutions Although the air quality problems caused by diesel exhaust are challenging, we believe they can be resolved through the application of high-efficiency emissions control technologies. As discussed in 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 vehicle'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 25 years, but have had only limited application in diesel vehicles. Based on the Clean Air Act requirements discussed in Section I.B.3, we are setting stringent new emission standards that will result in the use of these diesel exhaust emission control devices (see Section III). We are also finalizing changes to diesel fuel quality standards in order to enable these high-efficiency technologies (Section IV). Heavy- duty gasoline engines will also be able to reach the significantly lower emission levels envisioned in this rule by relying on the transfer of recent technology developments for light-duty applications, given the recent action taken to reduce sulfur in gasoline (65 FR 6698, February 10, 2000). To meet the new standards, application of high-efficiency exhaust emission controls for both PM and NOX will be needed. High- efficiency PM exhaust emission control technology has been available for several years, although engine manufacturers have generally not needed this technology in order to meet our PM emission standards. This technology has continued to improve over the years, especially with respect to durability and robust operation in use. It has also proven extremely effective in reducing exhaust hydrocarbon emissions. Thousands of such systems are now in use in fleet programs, especially in Europe. 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 that 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 heavy-duty vehicles are to attain the new standards. We believe this technology, like the PM technology, is dependent on the 15 ppm maximum diesel fuel sulfur levels being adopted in this rule 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. However, as discussed in Section III, application of this technology to diesels has some additional engineering challenges. In that section we discuss the current status of this technology. We also discuss the major development issues still to be addressed and the development steps that can be taken to address these issues. With the lead time available and the certainty of low-sulfur diesel fuel established by today's action, the evidence leaves us confident that the application of this technology to diesels will proceed at a reasonable rate of progress and will result in systems capable of achieving the standards. The need to reduce the sulfur in diesel fuel is driven by the requirements of the exhaust emission control technology that we project will be needed to meet the standards. The challenge in accomplishing the sulfur reduction is driven by the feasibility of 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. In consideration of the impacts that sulfur has on the efficiency, reliability, and fuel economy impact of diesel engine exhaust emission control devices, we believe that controlling the sulfur content of highway diesel fuel to the 15 ppm level is necessary and feasible, and, in the context of this rule's overall program, cost effective. 3. Basis For Action Under the Clean Air Act Section 202(a)(1) of the Act directs us to establish standards regulating the emission of any air pollutant from any class or classes of new motor vehicles or engines that, in the Administrator's judgment, cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare. Section 202(a)(3) requires that EPA set standards for heavy-duty trucks that reflect the greatest degree of emission reduction achievable through the application of technology which we determine will be available for the model year to which the standards apply. We are to give appropriate consideration to cost, energy, and safety factors associated with the application of such technology. We may revise such technology-based standards, taking costs into account, on the basis of information concerning the effects of air pollution from heavy-duty vehicles or engines and other sources of mobile source related [[Page 5008]] pollutants on the public health and welfare. Section 202(a)(3)(C) requires that promulgated standards apply for no less than three years and go into effect no less than 4 years after promulgation. This rule conforms with these statutory requirements. We believe the evidence provided in Section III and the Regulatory Impact Analysis (RIA) indicates that the stringent emission standards finalized 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 choosing 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 standards. The information regarding air quality and the contribution of heavy-duty engines to air pollution in Section II and the RIA provides strong evidence that emissions from such engines significantly and adversely impact public health or welfare. First, there is a significant risk that several areas will fail to attain or maintain compliance with the NAAQS for 1-hour ozone concentrations or PM10 concentrations during the period that these new vehicle and engine standards will be phased into the vehicle population, and that heavy-duty 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; however, the evidence indicates that some risk remains even after the reductions achieved by these new controls on heavy-duty vehicles and 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. Some of the toxic air pollutants associated with emissions from heavy-duty vehicles and engines include benzene, formaldehyde, acetaldehyde, dioxin, acrolein, and 1,3-butadiene. Third, emissions from heavy-duty 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. Based on this evidence, EPA believes that, for purposes of section 202(a)(1), emissions of NOX, VOCs, SOx and PM from heavy-duty trucks can reasonably be anticipated to endanger the public health or welfare. In addition, this evidence indicates that it will not be appropriate to modify the technology-based standards pursuant to section 202(a)(3)(B). EPA believes that it is required under section 202(a)(3)(A) to set technology-based standards that meet the criteria of that provision, and is not required to make an affirmative determination under section 202(a)(1). Instead EPA is authorized to take air quality into consideration under section 202(a)(3)(B) in deciding whether to modify or not set standard under section 202(a)(3)(A). In this case, however, EPA believes the evidence fully supports a determination under section 202(a)(1) to set standards, and a determination not to modify such standards under section 202(a)(3)(B). In addition, there is significant evidence that emissions from heavy-duty trucks contribute to levels of ozone such that large segments of the national population are expected to experience prolonged exposure over several hours at levels that present serious concern for the public health and welfare. The same is true for exposure to fine PM. These public health and welfare problems are expected to occur in many parts of the country, including areas that are in compliance with the 1-hour ozone and PM10 NAAQS (PM10 is particulate matter that is 10 microns or smaller). This evidence is an additional reason why the controls finalized today are justified and appropriate under the Act. While EPA sees this as additional support for this action, EPA also believes that the evidence of air pollution problems summarized above and described in greater detail elsewhere is an adequate justification for this rule independent of concern over prolonged exposure to ozone and fine PM levels. 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 each of these criteria. The discussion of the first test is substantially the same as the above discussion for the heavy-duty engine standards, because SOx and sulfate PM emissions from heavy-duty diesel vehicles are due to sulfur in diesel fuel. The substantial adverse effect of high diesel sulfur levels on diesel control devices or systems expected to be used to meet the heavy-duty standards is discussed in depth in Section III.F and in the RIA. In addition, our authority under section 211(c) is discussed in more detail in Appendix A to the RIA. C. Putting This Rule In Perspective There are several helpful perspectives to establish in understanding the context for this rule: the growing popularity of diesel engines, past progress and new developments in diesel emissions control, Tier 2 light-duty emission standards and other related EPA initiatives (besides the above-discussed rulemaking for highway heavy- duty engine emission standards in 2004), and recent actions and plans to control diesel emissions by the States and in other countries. 1. Diesel Popularity The diesel engine is increasingly becoming a vital workhorse in the United States, moving much of the nation's freight, and carrying out much of its farm, construction, and other labor. Diesel engine sales have grown significantly over the last decade, so that now about a million new diesel engines are put to work in the U.S. every year. Unfortunately, these diesel engines emit large quantities of harmful pollutants annually. Furthermore, although diesel emissions in this country come mostly from heavy-duty trucks and nonroad equipment, an additional source may grow out of auto manufacturers' plans to greatly increase the sales of diesel-powered light-duty vehicles (LDVs) and especially of light-duty trucks (LDTs), a category that includes the fast-selling sport-utility vehicles, minivans, and pickup trucks. These plans reflect the continuation of an ongoing dieselization trend, a trend recently most evident in the growing popularity of diesel-powered light heavy-duty trucks (8500 to 19,500 pounds). Diesel market penetration is working its way from larger to smaller highway applications and to a broader array of nonroad equipment applications. Finally, especially in Europe where diesels have already gained a broad consumer acceptance, the diesel engine is increasingly viewed as an attractive technology option for reducing emissions of gases that contribute to [[Page 5009]] global warming, because it has greater operating efficiency than a gasoline engine. 2. Past Progress and New Developments Since the 1970's, highway diesel engine designers have employed numerous strategies to meet our emissions standards, beginning with smoke controls, and focusing in the 1990's on increasingly stringent NOX, hydrocarbon, and PM standards. These strategies have generally focused on reducing engine-out emissions and not on exhaust emission controls, although relatively low-efficiency oxidation catalysts have been applied in some designs to reduce PM, with the recognition that their effectiveness is limited by sulfur in the fuel. On the fuel side, we set quality standards that provided emissions benefits by limiting the amount of sulfur and aromatics in highway diesel fuel beginning in 1993 (55 FR 34120, August 21, 1990). Our most recent round of standard setting for heavy-duty highway diesels occurred in 1997 (62 FR 54693, October 21, 1997), effective with the 2004 model year. These standards were recently reviewed in a final rulemaking (65 FR 59896, October 6, 2000). These actions will result in engines that emit only a fraction of the NOX, hydrocarbons, and PM produced by engines manufactured just a decade ago. We consider this an important first phase of our current initiative to reconcile the diesel engine with the environment. Nevertheless, certain characteristics inherent in the way diesel fuel combustion occurs have prevented achievement of emission levels comparable to those of today's gasoline-fueled vehicles. Although diesel engines provide advantages in terms of fuel economy, durability, and evaporative emissions, and have inherently low exhaust emissions of hydrocarbons and carbon monoxide, controlling NOX emissions is a greater challenge for diesel engines than for gasoline engines, primarily because of the ineffectiveness of three-way catalysis in the oxygen-rich and relatively cool diesel exhaust environment. Similarly, PM emissions, which are inherently low for properly operating gasoline engines, are more difficult to control in diesel engines, because the diesel combustion process tends to form soot particles. The challenge is somewhat complicated by the fact that historical diesel NOX control approaches tend to increase PM, and vice versa, but both are harmful pollutants that need to be controlled. Considering the air quality impacts of diesel engines and the potential for growth of diesels in the lighter-duty portion of the market, it is imperative that progress in diesel emissions control continue. Significant progress has already been made in the design of exhaust emission control devices for diesel applications, driven in part by the challenge presented by the stringent Tier 2 standards for light-duty vehicles. As discussed in detail in Section III, new exhaust emission control technologies for NOX, PM, and hydrocarbon reduction will allow a major advancement in diesel emissions control of a magnitude comparable to that ushered in by the automotive catalytic converter in the 1970's. However, changes in diesel fuel quality will be needed to enable these high-efficiency exhaust emission control devices. 3. Tier 2 Emissions Standards Auto manufacturers' design plans for new light-duty diesel vehicle models will be greatly affected by our recent adoption of stringent new emission standards for light-duty highway vehicles (referred to as ``Tier 2'' standards) that will phase in between 2004 and 2009. These Tier 2 standards will require significant improvements in electronic engine controls and catalysts on gasoline vehicles. We anticipate that these advances will be transferred over to heavy-duty gasoline vehicles in meeting the standards finalized in this rule. The Tier 2 NOX and PM standards, that apply equally to gasoline and diesel vehicles, will also require the use of high-efficiency emission control technologies on light-duty diesel vehicles. The low sulfur highway diesel fuel brought about by this rule will make it possible for designers to employ these high-efficiency exhaust emission control technologies in these light-duty applications. The timing of the fuel change provides for the use of these devices in time to satisfy Tier 2 phase-in requirements. The Tier 2 program phases in interim and final standards over a number of years, providing manufacturers the option of delaying some of their production of final Tier 2 designs until later in the phase-in. For vehicles up to 6000 lbs GVWR (LDVs) and light light-duty trucks (LLDTs)), the interim standards begin in 2004 and phase out by 2007, as they are replaced by the final Tier 2 standards. For vehicles between 6000 and 8500 lbs ( heavy light-duty trucks (HLDTs)), the interim standards begin in 2004 and phase out by 2009 as they are replaced by the final Tier 2 standards. A new category of vehicles between 8,500 and 10,000 lbs, medium-duty passenger vehicles (MDPVs), will follow the same phase-in schedule as HLDTs. Our assessment in the Tier 2 final rule is that the interim standards are feasible for diesel vehicles without a need for fuel quality changes. Manufacturers can take advantage of the flexibilities provided in the Tier 2 program to delay the need for light-duty diesels to meet the final Tier 2 levels until late in the phase-in period (as late as 2007 for LDVs and LLDTs, and 2009 for HLDTs and MDPVs). However, low sulfur fuel is expected to be needed for diesel vehicles designed to meet the final NOX and PM standards, because these vehicles are likely to employ light-duty versions of the sulfur- sensitive exhaust emission control technologies discussed in Section III. The gasoline quality changes and light-duty gasoline engine developments that will result from the Tier 2 rule will also help make it feasible for heavy-duty gasoline engines to meet the standards in this rule. 4. Mobile Source Air Toxics Rulemaking Passenger cars, on-highway trucks, and nonroad equipment emit hundreds of different compounds and elements. Several of these are considered to be known, likely, or possible human carcinogens. These include diesel exhaust, plus several VOCs such as acetaldehyde, benzene, 1,3-butadiene, formaldehyde, and acrolein. Trace metals may also be present in heavy-duty diesel engine emissions, resulting from metals in fuels and lubricating oil, and from engine wear. Several of these metals have carcinogenic and mutagenic effects. Important reductions in these and other mobile source air toxics have occurred under existing programs established under Clean Air Act Sections 202(a) (on-highway engine requirements), 211 (the fuel requirements), and 213 (nonroad engine requirements). Although these programs are primarily designed for control of criteria pollutants, especially ozone and PM10, they also achieve important reductions in diesel PM and gaseous air toxics through VOC and hydrocarbon controls. In addition to these programs, Section 202(l)(2) of the Act directs us to consider additional controls to reduce emissions of hazardous air pollutants from motor vehicles, their fuels, or both. Those standards are to reflect the greatest degree of emission reduction achievable through the application of technology which will be available, taking into account existing standards, costs, noise, energy, and safety factors. We published a proposed rule on mobile source air toxics on August 4, [[Page 5010]] 2000 (65 FR 48058). This MSAT final rule was signed on December 20, 2000. Interested parties should refer to the final rule if interested in the ultimate form of the regulation. The mobile source air toxics (MSATs) rule consists of four parts. First, we identify a list of 21 MSATs that are known to be emitted from motor vehicles or their fuels and are considered by the Agency to pose potential adverse human health risks. Diesel exhaust is included on this MSAT list because, as discussed in Section II, human epidemiological studies have suggested that diesel exhaust is associated with increased risk of adverse respiratory effects and lung cancer. Second, the MSAT rule considers the contribution of mobile sources to the nation's air toxics inventory and evaluates the toxics benefits of existing mobile source emission control programs. The benefits of the program as proposed are included in this analysis. Third, the MSAT final rule considers whether additional controls are appropriate at this time, given technological feasibility, cost, and the other criteria specified in the Act. The final rule includes a toxics performance standard applicable to reformulated gasoline and anti-dumping standards that apply to conventional gasoline. With regard to additional vehicle-based controls, we proposed that it is not appropriate at this time to set more stringent standards than the technology forcing standards found in this rule and our recently adopted Tier 2 rulemaking. Finally, because of our concern about the potential future health impacts of exposure to the public of air toxics from the remaining emissions from mobile sources in the future, we continue our toxics-related research activities and to conduct a future rulemaking to evaluate whether, based on the additional data, additional mobile source air toxics controls should be adopted. This rulemaking would be completed no later than 2004. EPA also intends to rely on today's rule to satisfy in part its obligations under section 202(l) of the Clean Air Act. In the mobile source air toxics NPRM, the Agency proposed a list of mobile source air toxics, including diesel exhaust, as well as a number of specific constituents of heavy-duty vehicle exhaust (gasoline and diesel).5 The emissions standards established in today's action result in the greatest achievable reductions of diesel PM and heavy-duty vehicle NMHC. The Agency is scheduled to finalize the mobile source air toxics rulemaking on or before December 20, 2000. --------------------------------------------------------------------------- \5\ 65 FR 48058, August 4, 2000. --------------------------------------------------------------------------- 5. Nonroad Engine Standards and Fuel Although this rule covers only highway diesel engines and fuel, it is clear that potential requirements for nonroad diesel engines and fuel are related. It is expected that nonroad diesel fuel quality, currently unregulated, may need to be controlled in the future in order to reduce the large contribution of nonroad engines to NOX and PM inventories. Refiners, fuel distributors, states, environmental organizations, and others have asked that we provide as much information as possible about the future specifications for both types of fuel as early as possible. We do plan to give further consideration to additional control of nonroad engine emissions. As discussed below in Section VIII, an effective control program for these engines requires the resolution of several major issues relating to engine emission control technologies and how they are affected by fuel sulfur content. The many issues connected with any rulemaking for nonroad engines and fuel warrant serious attention, and we believe it is premature for us to take any action on this initiative in this rule. We plan to initiate action in the future to formulate proposals that would address both nonroad diesel fuel and engines. 6. State Initiatives The California Air Resources Board (ARB) and local air quality management districts within California are also pursuing measures to better control diesel emissions. Key among these efforts is work resulting from the Board's designation of particulate emissions from diesel-fueled engines as a toxic air contaminant (TAC) on August 27, 1998. TACs are air pollutants that may cause or contribute to an increase in death or serious illness or may pose a present or future hazard to human health. The TAC designation was based on research studies showing that emissions from diesel-fueled engines may cause cancer in animals and humans, and that workers exposed to higher levels of emissions from diesel-fueled engines are more likely to develop lung cancer. In September 2000 the ARB approved a Diesel Risk Reduction Plan developed by its staff following an extensive public process.6 This plan includes several California measures related to highway diesel vehicles, including the major elements of the program we are establishing on a nationwide basis in this final rule. Because truck travel from other states has a large effect on California's air quality, the plan and the Board's resolution further encourages the EPA adopt this nationwide program, as well as other diesel-related emissions reduction programs. --------------------------------------------------------------------------- \6\ State of California Air Resources Board Resolution 00-30, September 28, 2000. --------------------------------------------------------------------------- The ARB has also adopted stringent new emission requirements for urban transit buses and is considering similar requirements for school buses.7 This program is aimed at encouraging the use of clean alternative fuels and high-efficiency diesel emission control technologies. Their program includes requirements for zero-emissions buses, fleet average NOX levels, and retrofits for PM control, as well as model year 2007 NOX and PM standards levels of 0.2 and 0.01 g/bhp-hr, respectively (equal to the levels finalized in this rule). It also requires that all diesel fuel used by transit agencies after July 1, 2002 must meet a cap of 15 ppm sulfur. This is a much earlier schedule than that finalized in this rule, to support the ARB's proposed transit bus fleet program. --------------------------------------------------------------------------- \7\ ``Notice of Public Hearing To Consider the Adoption of a Public Transit Bus Fleet Rule and Emission Standards For New Urban Buses'', California ARB, November 30, 1999, and ARB Resolution 00-2, dated February 24, 2000. --------------------------------------------------------------------------- Other states, most notably Texas, have taken steps toward adopting programs for cleaner diesel fuel and cleaner diesel engines. On December 6, 2000, the Texas Natural Resource Conservation Commission adopted a program that, among other things, would require the capping of diesel fuel sulfur levels in many counties to 15 ppm by June 2006.8 This proposal exemplifies the importance that states with air quality problems have attached to clean diesel fuel, and specifically to the 15 ppm maximum sulfur requirement in 2006 being set in this rule --------------------------------------------------------------------------- \8\ Title 30, Texas Administrative Code, Chapter 114, Subchapter H, Division 2. Also see Texas Natural Resource Conservation Commission website www.tnrcc.state.tx.us.. --------------------------------------------------------------------------- 7. Retrofit Programs Many States facing air quality improvement challenges have expressed strong interest in programs that will reduce emissions from existing highway and nonroad diesel engines through the retrofitting of these engines with improved emission control devices. The urban transit bus program adopted by the California ARB includes such a retrofit requirement as one of its major components (see Section I.C.6). In March 2000 we announced our own Diesel Retrofit Initiative to support and [[Page 5011]] encourage fleet operators, air quality planners, and retrofit manufacturers in creating effective retrofit programs. These programs are appealing because the slow turnover of the diesel fleet to the new low-emitting engines makes it difficult to achieve near-term air quality goals through new engine programs alone. Some of the exhaust emission control technologies discussed in this rule are especially appealing for use in retrofits because they can be fitted to an existing vehicle as add-on devices without major engine modifications, although some of the more sophisticated systems that require careful control of engine parameters may be more challenging. Because of the uncertainty at this time in how and when such programs may be implemented, our analysis for today's rule does not calculate any benefits from them. Nevertheless, we believe that this program can enable the viability of these retrofit technologies. We expect that large emission benefits from the existing fleet could be realized as a result of the fuel changes we are finalizing here, combined with retrofit versions of the technologies that will be developed in response to the finalized engine standards. These benefits will be especially important in the early years of the program when new vehicles standards are just beginning to have an impact, and when States and local areas need to gain large reductions to attain air quality goals. 8. Actions In Other Countries There is substantial activity taking place in many countries related to the regulation of diesel fuel and engines. The large light- duty vehicle market share enjoyed by diesels in many European countries has helped to stir innovation in dealing with diesel emissions problems. Advanced emissions control technologies are being evaluated there in the in-use fleet and experience gained from these trials is helping to inform the diesel emissions control discussion in the U.S. In addition, several European countries have low sulfur diesel fuel, with maximum sulfur levels varying from 10 to 50 ppm, and so experience gained from the use of these fuels, though not completely transferable to the U.S. situation, also provides valuable experience. European Union countries will limit sulfur in diesel fuel to 50 ppm by 2005, and even more aggressive plans are being discussed or implemented. The United Kingdom made a rapid conversion to 50 ppm maximum sulfur diesel fuel in 1999 by offering tax incentives. This change occurred with much smaller refinery investments than had been predicted, and some refinery production there is actually at levels well below the 50 ppm cap. Germany is moving forward with plans to introduce a 10 ppm sulfur cap for diesel fuel by 2003, also via tax incentives, and is attempting to get the 50 ppm specification that was adopted by the European Commission revised downward to the 10 ppm cap level. The Commission is reviewing the implications of moving to this level. One European country has had extensive experience with the transition to low sulfur diesel fuel. In the early 1990's, Sweden decided to take advantage of the environmental benefits of 10 ppm sulfur/low aromatics fuel by introducing it with a reduction in the diesel fuel tax. The program has been quite successful, and in excess of 90 percent of the highway diesel fuel used there is of this 10 ppm maximum sulfur class.9 --------------------------------------------------------------------------- \9\ Memo from Thomas M. Baines to Docket A-99-06, October 29, 1999, Docket #A-99-06, Item II-G-12. --------------------------------------------------------------------------- The government of Canada has expressed its intent to harmonize its fuel regulations with the U.S. fuels standards being adopted today.10 This would simplify the operation of new-technology vehicles that cross the U.S-Canada border. However, the success of the U.S. program does not depend on harmonized diesel fuel standards, and Section VI.H discusses how differences between the future fuel specifications in the U.S. and those in Canada and Mexico may be accommodated. --------------------------------------------------------------------------- \10\ ``Process Begins to Develop Long term Agenda to Reduce Air Pollution from Vehicles and Fuels'', Environment Canada press release, May 26, 2000. --------------------------------------------------------------------------- II. The Air Quality Need and Projected Benefits A. Overview Heavy-duty vehicle emissions contribute to air pollution with a wide range of adverse health and welfare impacts. Emissions of VOC, CO, NOX, SOx, and PM from HD vehicles contribute a substantial percentage of the precursors or direct components of ambient concentrations of ozone, PM, sulfur and nitrogen compounds, aldehydes, and substances known or considered likely to be carcinogens. Emissions of VOCs include some specific substances known or suspected to cause cancer. Of particular concern is human epidemiological evidence linking diesel exhaust to an increased risk of lung cancer, and the Agency is also concerned about the noncancer health effects of diesel exhaust We have finalized on December 20, 2000 a rule which lists diesel particulate matter and diesel exhaust organic gases as a mobile source air toxic under section 202(l) of the Clean Air Act, and the particulate matter standard finalized today reflects the greatest degree of emissions reductions achievable under section 202(l) for on- highway heavy-duty vehicle PM emissions. Heavy-duty vehicle emissions also cause adverse environmental effects including visibility reductions, acid rain, nitrification and eutrophication of water bodies. Emissions from heavy-duty vehicles, which are predominantly diesel- powered, account for substantial portions of the country's ambient PM and ground-level ozone levels. By 2007, we estimate that heavy-duty vehicles will account for 28 percent of mobile source NOX emissions (including highway and non-road), and 20 percent of mobile source PM emissions. These proportions are even higher in some urban areas, such as Atlanta and Los Angeles. Urban areas, which include many poorer neighborhoods, can be disproportionately impacted by HDV emissions because of heavy traffic in and out of densely populated urban areas. The Agency developed new emissions inventories and conducted new air quality modeling for this rule to determine the risk of exposure to unhealthy ambient concentrations of ozone and particulate matter in 2007, 2020 and 2030. This analysis, supplemented with local air quality modeling and other information on emissions and air quality trends, indicates that an appreciable number of the 45 areas with a total population of 128 million people face a significant risk of violating the 1-hour ozone standard between 2007 and 2030. Ten PM10 nonattainment areas with 28 million people face a significant risk of experiencing particulate matter levels that violate the PM10 standard during the same period. Under the mandates and authorities in the Clean Air Act, federal, state, and local governments are working to bring ozone and particulate levels into compliance with the 1-hour ozone and PM10 NAAQS through SIP attainment plans. Areas that reach attainment without reductions from this rule are likely to need additional reductions to ensure that future air quality continues to achieve ozone and PM standards, and areas that seek redesignation to attainment may use the reductions from this rule in future maintenance plans. The heavy-duty vehicle and engine emission standards, along with the diesel fuel sulfur standard finalized today, will have a dramatic impact in [[Page 5012]] reducing the large contribution of HDVs to air pollution. These standards will result in substantial benefits to public health and welfare through significant annual reductions in emissions of NOX, PM, NMHC, carbon monoxide, sulfur dioxide, and air toxics. For example, we project a 1.8 million ton reduction in NOX emissions from HD vehicles in 2020, which will increase to 2.6 million tons in 2030 when the current HD vehicle fleet is completely replaced with newer HD vehicles that comply with these emission standards. When coupled with the emission reductions projected to result from the Phase 1 (model year 2004) HDV standards, the emission reductions from heavy-duty vehicles are projected to be as large as the substantial reductions the Agency expects from light-duty vehicles as a result of its recently promulgated Tier 2 rulemaking. In sum, the Agency's air quality modeling and other evidence demonstrates that ambient concentrations of ozone, particulate matter, sulfur and nitrogen compounds, VOCs, air toxics, CO and diesel exhaust are anticipated to endanger public health, welfare and the environment in the time period between 2007 and 2030. Emission reductions expected from today's action are predicted to lessen future ambient concentrations of ozone and particulate matter and associated adverse public health and welfare effects. B. Public Health and Welfare Concerns 1. Health and Welfare Concerns Raised During Public Hearings The Agency received a significant number of comments on this section during the public hearings and in written comments from interested parties. Comments are addressed in this section as well as in the Response to Comment document that accompanies this action. Throughout the five public hearings held around the country on the proposed heavy-duty engine and diesel fuel rule, the Agency received strong public support at each venue for increasing the stringency of heavy-duty truck and bus emission standards, and for further controls on sulfur in diesel fuel, in order to enable the necessary exhaust emission control. In addition to the 55,000 comments received from citizens in support of the Agency proposal to clean diesel fuel by mid- 2006 and reduce emissions from diesel engines in 2007, we received 8,500 comments from citizens urging the Agency to act prior to 2007. Public officials and representatives of environmental, public health, or community-based organizations testified regularly about the link between public health ailments, such as asthma and lung cancer, and air pollution caused by diesel exhaust and particulate matter. In different ways, many noted that the impact of diesel soot is compounded by the fact that it is discharged at street level where people live and breathe. A regular complaint was the close proximity of bus depots, transfer terminals, and heavily-trafficked roadways to homes and apartment buildings, and in particular, to hospitals, playgrounds and schools. A common theme revolved around the notion that since asthma is an incurable disease, it was of utmost importance to help reduce the severity and frequency of attacks by reducing environmental triggers such as ozone, particulate matter and diesel exhaust. Major industries represented during these public hearings were the heavy-duty vehicle engine manufacturers, the oil industry, and the commercial truckers. While each had a different perspective, most supported the underlying intent of the proposal to improve public health and welfare, and some also supported the specific requirements as proposed. For those who objected to the proposal, the main thrust of their concerns related to the stringency and public health necessity of the new standards and the diesel fuel sulfur requirement. Largely in their written comments, these industries raised questions about the need for additional reductions in order to meet existing ozone and PM national ambient air quality standards and took exception with the Agency's characterization of diesel exhaust as a human carcinogen at environmental levels of exposure. Some industry commenters also challenged the Agency's reliance on public welfare and environmental effects such as visibility impairment and eutrophication of water bodies because the Agency had insufficiently quantified the benefits that would result from new standards on heavy-duty vehicles and diesel fuel. The following subsections present the available information on the air pollution situation that is likely to exist without this rule for each ambient pollutant. We also present information on the improvement that is expected to result from this rule. 2. Ozone and Its Precursors a. Health and Welfare Effects From Short-Term Exposures to Ozone NOX and VOC are precursors in the photochemical reaction which forms tropospheric ozone. A large body of evidence shows that ozone can cause harmful respiratory effects including chest pain, coughing, and shortness of breath, which affect people with compromised respiratory systems most severely. When inhaled, ozone can cause acute respiratory problems; aggravate asthma; cause significant temporary decreases in lung function of 15 to over 20 percent in some healthy adults; cause inflammation of lung tissue; produce changes in lung tissue and structure; may increase hospital admissions and emergency room visits; and impair the body's immune system defenses, making people more susceptible to respiratory illnesses. Children and outdoor workers are likely to be exposed to elevated ambient levels of ozone during exercise and, therefore, are at greater risk of experiencing adverse health effects. 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. There is strong and convincing evidence that exposure to ozone is associated with exacerbation of asthma-related symptoms. Increases in ozone concentrations in the air have been associated with increases in hospitalization for respiratory causes for individuals with asthma, worsening of symptoms, decrements in lung function and increased medication use. Studies have also indicated that exposure to particulate matter can be associated with altered lung function and increased respiratory symptoms, and asthmatic children are considered to be particularly sensitive to these effects. In addition, exposures to particulate matter or ozone have been shown to have a priming effect for responsiveness to allergens, with the pollutant exposure leading to heightened responses to allergens among allergic asthmatics. It is not believed, based on the current evidence, that exposure to outdoor pollutants such as ozone or particulate matter is a cause of asthma. Asthma is one of the most common and costly diseases in the United States. According to the President's Task Force on Environmental Health Risks and Safety Risks to Children, America is in the midst of an asthma epidemic.11 [[Page 5013]] Since 1980, the number of asthma sufferers in the United States has more than doubled from 6.7 million to 17.3 million in 1998.12 Today, more than 5 percent of the US population has asthma. On average, 15 people died every day from asthma in 1995, and the death rate has nearly tripled since 1975. In 1998, the cost of asthma to the U.S. economy was estimated to be $11.3 billion, with hospitalizations accounting for the single largest portion of the cost.13 A recent report by the Pew Environmental Health Commission at Johns Hopkins School of Public Health estimates that by 2010, 22 million Americans will suffer from asthma, or one in 14 Americans and one in every five families.14 At present, asthma cannot be cured, only controlled. --------------------------------------------------------------------------- \11\ Asthma and the Environment: A Strategy to Protect Children, President's Task Force on Environmental Health Risks and Safety Risks to Children, January 28, 1999, Revised May, 2000. \12\ Asthma Prevention Program of the National Center for Environmental Health, Centers for Disease Control and Prevention, ``At-A-Glance, 1999; Centers for Disease Control and Prevention, CDC, Surveillance for Asthma--United States, 1960-1995,'' MMWR 47 (No. SS-1) (April 1998). \13\ Asthma Statistics, National Institutes of Health, National, Heart, Lung, and Blood Institute, January, 1999. \14\ Attack Asthma: Why America Needs A Public Health Defense System to Battle Environmental Threats, Pew Environmental Health Commissions at the Johns Hopkins School of Public Health, June, 2000. --------------------------------------------------------------------------- To address this growing public health problem, the President's Task Force on Environmental Health Risks and Safety Risks to Children ranked asthma as its highest priority. The President's Task Force created and charged the Asthma Priority Area Workgroup, co-chaired by EPA and the Department of Health and Human Services, with reviewing current Federal efforts to address the issue, and to make recommendations. In May, 2000, the Task Force issued a strategy that focused on developing a greater understanding of the role environmental factors associated with the onset of asthma; and triggers of asthma. The report found that ``children with asthma have long been recognized as particularly sensitive to outdoor air pollution,'' The report noted that ``25 percent of children in America live in areas that regularly exceed EPA limits for ozone.'' The first guiding principle was to focus efforts to ``eliminate the disproportionate impact of asthma in minority populations and those living in poverty.'' Testimony received during the Agency's five public hearings on this rule contained numerous references and detailed personal accounts as to the severe and sometimes fatal impact of asthma on the lives of American citizens. b. Current and Future Nonattainment Status With the 1-Hour Ozone NAAQS Today, ground level ozone remains a pervasive pollution problem in the United States. As of July, 2000, 102 million people (1999 census) lived in 31 metropolitan areas designated nonattainment under the 1- hour ozone NAAQS.15 This is a sharp decline from the 101 nonattainment areas originally identified under the Clean Air Act Amendments of 1990, but elevated ozone concentrations remain a serious public health concern throughout the nation. --------------------------------------------------------------------------- \15\ Memorandum to Air Docket, September 18, 2000. Information on ozone nonattainment areas and populations as of July 31, 2000 from US EPA website www.epa.gov/airs/nonattn.html, USA Air Quality Nonattainment Areas, Office of Air Quality Planning and Standards. --------------------------------------------------------------------------- Over the last decade, declines in ozone levels were found mostly in urban areas, where emissions are heavily influenced by controls on mobile sources and their fuels.16 Twenty-three metropolitan areas have realized a decline in ozone levels since 1989, but at the same time, ozone levels in 11 metropolitan areas with 7 million people have increased.17 Regionally, California and the Northeast have recorded significant reductions in peak ozone levels, while four other regions (the Mid-Atlantic, the Southeast, the Central and Pacific Northwest) have seen ozone levels increase. --------------------------------------------------------------------------- \16\ National Emissions Trends database. \17\ National Air Quality and Emissions Trends Report, 1998, March, 2000, at 28. --------------------------------------------------------------------------- The highest ambient concentrations are currently found in suburban areas, consistent with downwind transport of emissions from urban centers. Concentrations in rural areas have risen to the levels previously found only in cities. Over the last decade, ozone levels at 17 of our National Parks have increased, and in 1998, ozone levels in two parks were 30 to 40 percent higher than the ozone NAAQS. i. Results of Photochemical Ozone Modeling and Analysis of Emissions Inventories In conjunction with this rulemaking, the Agency performed ozone air quality modeling for nearly the entire Eastern U.S covering metropolitan areas from Texas to the Northeast.18 This ozone air quality modeling was based upon the same modeling system as was used in the Tier 2 air quality analysis, with the addition of updated inventory estimates for 2007 and 2030.19 This modeling supports the conclusion that there is a broad set of areas with predicted ozone concentrations in 2007 and 2030 at or above 0.125 ppm, in the baseline scenarios without additional emission reductions. EPA established the 1-hour standard at 0.12 parts per million (ppm) daily maximum 1-hour average concentration not to be exceeded more than once per year on average. Compliance with the 1-hour standard is judged on the basis of the most recent three years of ambient air quality monitoring data. --------------------------------------------------------------------------- \18\ EPA also performed ozone air quality modeling for the western United States but, as described further in the air quality technical support document, model predictions were well below corresponding ambient concentrations. Because of poor model performance for this region of the country, the results of western ozone modeling were not relied on for this rule. \19\ Consistent with a commitment expressed in the proposal, the Agency released the emissions inventory inputs for, and a description of, ozone modeling into the public record (docket number A-99-06), and also onto a website developed expressly for this purpose, on a continuous basis as they were developed. Further discussion of this modeling, including evaluations of model performance relative to predicted future air quality, is provided in the air quality modeling Technical Support Document (TSD). --------------------------------------------------------------------------- We have compared and supplemented our own ozone modeling with other modeling studies, submitted to us as state implementation plan (SIP) revisions, or brought to our attention through our consultations with states on SIP revisions that are in development. The ozone modeling in the SIP revisions has the advantage of using emission inventories that are more specific to the area being modeled, and of using meteorological conditions selected specifically for each area. Also, the SIP revisions included other evidence and analysis, such as analysis of air quality and emissions trends, observation-based models that make use of data on concentrations of ozone precursors, alternative rollback analyses, and information on the responsiveness of the air quality model. For some areas, we decided that the predictions of 1-hour ozone exceedances from our modeling were less reliable than conclusions that could be drawn from this additional evidence and analysis. For example, in some areas our episodes did not capture the meteorological conditions that have caused high ozone, while local modeling did so. Thus, these local analyses are considered to be more extensive than our own modeling for estimating whether there would be NAAQS nonattainment without further emission reductions, when interpreted by a weight of evidence method which meets our guidance for such modeling. Photochemical ozone modeling conducted for this rulemaking was based in part on updated national emissions inventories for all sources. National emission trends for NOX [[Page 5014]] predict a significant decline from 1996 to 2007, a leveling off of the downward trend between 2007 to 2020, and an increase in NOX inventories from 2020 to 2030. By 2030, national NOX levels are estimated to reach levels that are within ten percent of 2007 levels. Predictions of national VOC emissions indicate a reduction from 1996 to 2007, followed by an increase between 2007 and 2030 resulting in 2030 levels that are estimated to be 10 percent greater than VOC emissions levels in 2007. In metropolitan ozone nonattainment areas, such as Charleston, Chicago and Houston, NOX or VOC emissions in 2030 are predicted to reach or exceed 2007 levels. These estimated national and metropolitan area emissions inventories of ozone precursors are consistent with the conclusions reached by analysis of ozone modeling conducted for this rule that additional reductions are needed in order to enable areas to reach and maintain attainment of the ozone standard between 2007 and 2030. The Agency conducted ozone modeling based on inventories developed with and without reductions from this rulemaking for three future years: 2007, 2020 and 2030. The year 2007 was chosen because it is also the first year of implementation for the new standards adopted in today's action. It is also the year that nine major urban areas with a history of persistent and elevated ozone concentrations must demonstrate attainment, and is also relevant to the South Coast Air Basin of California (South Coast) with an attainment date of 2010. In addition, modeling was performed for 2030 when the full benefits of the rule are expected to be realized and for 2020 which represents an intermediate year between the start of the program and full turnover of the affected vehicle fleet. The year 2020 is also representative of the period when areas that have come into attainment may need additional reductions in order to maintain the standard. Today's rule will provide a substantial reduction in emissions of ozone precursors, particularly NOX. These emissions reductions will greatly lower ozone concentrations which will help federal and State efforts to bring about attainment of the current 1- hour ozone standard. As described in the Air Quality Modeling Technical Support Document for this rule, EPA performed regional scale ozone modeling for the Eastern U.S. to assess the impacts of the controls in this rule on predicted 1-hour ozone exceedances. The results of this modeling were examined for those 37 areas in the East for which EPA's modeling predicted exceedances in 2007, 2020 and/or 2030 and current 1- hour design values are above the standard or within 10 percent of the standard. The results for these areas combined indicate that there will be substantial reductions in the number of exceedances and the magnitude of high ozone concentrations in both 2020 and 2030 due to this rule. The modeling also indicates that without the rule, exceedances would otherwise increase by 37 percent between 2020 and 2030 as growth in emissions offsets the reductions from Tier 2 and other current control programs. For all areas combined, the rule is forecast to provide a 33 percent reduction in exceedances in 2020 and a 38 percent reduction in 2030. The total amount of ozone above the standard is expected to decline by nearly 37 percent in 2020 and 44 percent in 2030. Also, daily maximum ozone exceedances are lowered by 5 ppb on average in 2020 and nearly 7 ppb in 2030. The modeling forecasts an overall net reduction of 39 percent in exceedances from 2007, which is close to the start of this program, to 2030 when controls will be fully in place. In addition, the results for each individual area indicates that all areas are expected to have fewer exceedances in 2030 with the HDV controls than without this rule. During the public comment period on the proposed rule, EPA received several comments that expressed concern about potential increases in ozone that might result from this rule. As indicated above, the air quality modeling results indicate an overall reduction in ozone levels in 2007 and 2030 during the various episodes modeled. Examining individual areas, nearly the entire country is projected to benefit substantially from the reductions in this rule.20 There is a metropolitan area that EPA modeled as having exceedances with the one- hour ozone standard under baseline conditions in 2007 through 2030, which the Agency's modeling for the HDV rule estimated could have less than a 3 percent increase in its peak ozone levels in 2020 and 2030 and small net increase (i.e., less than 1 ppb) in levels above the 1-hour standard in 2030. However, EPA's air quality modeling did not predict an increase in the number of exceedances in this CMSA/MSA in 2020 and a decrease in exceedances occurred in 2030. In another CMSA/MSA in another State, in 2030 there was less than a one percent increase in the summer peak level. Yet, this area had fewer exceedances and lower ozone above the 1-hour standard in both 2020 and 2030 under the rule. EPA expects that the States will have State Implementation Plans that will consider federal controls and complement them with State actions to provide attainment and will work with the States to ensure this occurs. --------------------------------------------------------------------------- \20\ The air quality modeling was performed for the Eastern region of the United States, but EPA also expects the rule to benefit nonattainment areas throughout the entire nation, including California. --------------------------------------------------------------------------- Considering all of EPA's air quality modeling results, it is clear that the significant ozone reductions from this rule outweigh the limited ozone increases that may occur in the future assuming no additional reductions from federal or local controls. Additional details on this are provided in the Response to Comments document and in EPA's Heavy Duty Rule Air Quality Modeling Technical Support Document. Furthermore, EPA's Regulatory Impact Analysis for this rule shows significant health and welfare benefits occurring from the ozone reductions that the rule provides (see details on the benefits in Section V.F.5 of the preamble and Chapter VII of the RIA). ii. Areas At Risk of Exceeding the 1-Hour Ozone Standard in the Future This section presents the Agency's conclusions about the risk of future nonattainment for 45 areas listed in Table II.B-1 based on photochemical ozone modeling conducted for this rule and other evidence such as local air quality modeling.21 The areas listed in Table II.B-1 are separated into two broad groups: (1) Those areas with attainment dates in 2007 or 2010 that will benefit from reductions from this rule to attain and maintain the standard; and (2) those areas with attainment dates prior to 2007 that will benefit from reductions from this rule to maintain the standard after their attainment dates. Because ozone concentrations causing violations of the 1-hour ozone standard are well established to endanger public health and welfare, this indicates that it is appropriate for the Agency to set new standards for heavy-duty vehicles. The following discussion follows these groupings from top to bottom. A more detailed discussion is found in the Regulatory Impact Analysis (RIA). --------------------------------------------------------------------------- \21\ In the proposal, we relied on photochemical ozone modeling performed for recently promulgated standards on light duty vehicles, or Tier 2. The results presented in this final rulemaking for heavy- duty vehicles and diesel fuel are largely consistent with the findings presented in the proposal, with small differences due to updated emissions inventories. As stated in the proposal, the ozone modeling methodologies used in the proposal and presented here in the final rule are identical. --------------------------------------------------------------------------- Ten metropolitan areas contained within designated ozone nonattainment areas have statutorily-defined attainment dates of 2007 or 2010, or [[Page 5015]] have requested attainment date extensions to 2007. These 10 areas are listed at the top of Table II.B-1, and are New York City, Houston, Hartford, New London, Chicago, Milwaukee, Dallas, Beaumont-Port Arthur, Los Angeles, and Southeast Desert. Each of these areas needs additional emission reductions in order to reach attainment by 2007, and to maintain the standards in the future. Some of these areas have emission reduction shortfalls that are identified in their attainment demonstrations (i.e., South Coast Air Basin, New York and Houston), and reductions from this rule will assist State efforts to reach attainment.22 Three other areas-- Southeast Desert, Hartford, New London--are subject to ozone transport from upwind areas with identified shortfalls (South Coast and New York), and depend upon attainment from these upwind areas to reach attainment themselves. We have received attainment plans for two areas in Texas (Dallas and Beaumont-Port Arthur), and the Agency is likely to consider the reductions from this rule in its proposed approval of these attainment plans in Federal Register notices. Finally, there are two areas in the Midwest--Chicago and Milwaukee--that have incorporated reductions from this rule into their regional ozone modeling, and plan to rely on reductions from this rule to support their 2007 attainment demonstration.23 --------------------------------------------------------------------------- \22\ The South Coast's ``additional measures'' which rely on new technologies, are located in its 1994 SIP. \23\ Technical Support Document, Midwest Subregional Modeling: 1-Hour Attainment Demonstration for Lake Michigan Area and Emissions Inventory, Illinois Environmental Protection Agency, Indiana Department of Environmental Management, Michigan Department of Environmental Quality, Wisconsin Department of Natural Resources, September 27, 2000, at 14 and at 8. --------------------------------------------------------------------------- For all ten areas, even if all shortfalls were filled by the States, there is some risk that at least some of the areas will not attain the standards by their attainment dates of 2007, or 2010 for Los Angeles. In that event, the reductions associated with this program, which increase substantially after 2007, will help assure that any residual failures to attain are remedied. Finally, there is also some risk that the areas will be unable to maintain attainment after 2007. Considered collectively, there is a significant risk that some areas will not be in attainment throughout the period when the new standards will reduce heavy-duty vehicle emissions. The rest of the areas have required attainment dates prior to 2007, or have no attainment date but are subject to a general obligation to have a SIP that provides for attainment and maintenance. These 34 areas, according to our modeling, are at risk of exceeding the ozone NAAQS between 2007 and 2030. These areas will be able to rely on reductions from this rule to continue to maintain the standard after attainment is reached, and will be able to take credit for this program in their maintenance plans when they seek redesignation to attainment of the ozone standard. If any of these areas reach attainment, and then fall back into nonattainment, or fail to reach attainment by 2007, reductions from this rule will assist these areas in achieving the ozone standard. If an area does not choose to seek redesignation, the continuing reductions from this rulemaking will help ensure maintenance (i.e., prevent future exceedances) with the 1-hour standard after initial attainment is reached. Areas with attainment dates prior to 2007 are presented in two groupings in the table at the end of this section: a group of 20 areas in the middle of Table II.B-1, and a group of 15 areas at the bottom of Table II.B-1. For the middle group of 20 areas, EPA and the States are pursuing the established statutory processes for attaining and maintaining the ozone standard, or have already redesignated these areas to attainment with a maintenance plan (e.g., Cincinnati). EPA has re-instated the 1-hour ozone standard to some of these areas, restoring the applicability of these processes to them. The Agency believes that there is a significant risk that future air quality in a number of these areas will exceed the ozone standard at some time in the 2007 and later period. This belief is based on three factors: (1) Recent exceedances in 1997-1999, (2) predicted exceedances in 2007, 2020 or 2030 after accounting for existing mobile source requirements and other local or regional controls currently in place or required, and (3) our assessment of the magnitude of recent violations, the year-to-year variability of meteorological conditions conducive to ozone formation, transport from areas with later attainment dates, and other variables inherent in predicting future attainment such as the potential for some areas to experience unexpectedly high economic growth rates, growth in vehicle miles traveled, varying population growth from area to area, and differences in vehicle choice. Only a subset of these 20 areas have yet adopted specific control measures that have allowed the Agency to fully approve an attainment plan. For some of these areas, we have proposed a finding, based on all the available evidence, that the area will attain by its applicable attainment date. We have approved a 10-year maintenance plan for Cincinnati, OH from 1999 to 2009. However, in many cases, these proposals depend on the State adopting additional emission reduction measures. The RIA provides more information on our recent proposals on attainment demonstrations and maintenance plans.24 Until the SIPs for these areas are actually submitted, reviewed and approved by EPA, there is some risk that these areas will not adopt fully approvable SIPs. --------------------------------------------------------------------------- \24\ We have recently proposed favorable action, in some cases with a condition that more emission reductions be obtained, on attainment demonstrations in these areas with attainment dates prior to 2007: Philadelphia, Washington-Baltimore, Atlanta, and St. Louis. --------------------------------------------------------------------------- Finally, there are 15 additional metropolitan areas for which the available ozone modeling and other evidence is less clear regarding the need for additional reductions (see Table II.B-1). Our ozone modeling predicted these areas to need further reductions to avoid exceedances in 2007, 2020 or 2030. The recent air quality monitoring data for these areas shows ozone levels with less than a 10 percent margin below the NAAQS. We believe there is a risk that future ozone levels will be above the NAAQS because of the year-to-year variability of meteorological conditions conducive to ozone formation, or because local emissions inventories may increase faster than national inventories. iii. Conclusion In sum, without these reductions, there is a significant risk that an appreciable number of the 45 areas, with a population of 128 million people in 1999, will violate the 1-hour ozone standard during the time period when these standards will apply to heavy-duty vehicles. The evidence summarized in this section, and presented in more detail in the air quality modeling TSD and the RIA, supports the Agency's belief that emissions of NOX and VOC from heavy-duty vehicles in 2007 and later will contribute to a national ozone air pollution problem that warrants regulatory action under section 202(a)(3) of the Act. [[Page 5016]] Table II.B-1 a [Areas and 1999 Populations at Risk of Exceeding the Ozone Standard between 2007 and 2030] ------------------------------------------------------------------------ 1999 Population MSA/CMSA/State (in millions) ------------------------------------------------------------------------ Areas with 2007/2010 Attainment Dates (Established or Requested) ------------------------------------------------------------------------ Beaumont-Port Arthur, TX................................... 0.4 Chicago-Gary-Kenosha, IL-IN-WI............................. 8.9 Dallas-Fort Worth, TX...................................... 4.9 Hartford, CT............................................... 1.1 Houston-Galveston-Brazoria, TX............................. 4.5 Los Angeles-Riverside-Orange County, CA.................... 16.0 Milwaukee-Racine, WI....................................... 1.6 New London-Norwich, CT-RI.................................. 0.3 New York-Northern New Jersey-Long Island, NY-NJ-CT-PA...... 20.2 Southeast Desert, CA....................................... 0.5 10 areas................................................... 58.4 ------------------------------------------------------------------------ Areas with Pre-2007 Attainment Dates or No Specific Attainment Date, with a Recent History of Nonattainment. ------------------------------------------------------------------------ Atlanta, GA................................................ 3.9 Baton Rouge, LA............................................ 0.6 Birmingham, AL............................................. 0.9 Boston-Worcester-Lawrence, MA-HN-ME-CT..................... 5.7 Charlotte-Gastonia-Rock Hill, NC-SC........................ 1.4 Detroit-Ann Arbor-Flint, MI MSA............................ 5.5 Huntington-Ashland, WV-KY-OH............................... 0.3 Louisville, KY-IN.......................................... 1.0 Macon, GA MSA.............................................. 0.3 Memphis, TN-AR-MS.......................................... 1.1 Nashville, TN.............................................. 1.2 Philadelphia-Wilmington-Atlantic City, PA-NJ-DE-MD......... 6 Richmond-Petersburg, VA.................................... 1 Sacramento-Yolo, CA........................................ 1.7 San Diego, CA.............................................. 2.8 San Francisco-Oakland-San Jose, CA......................... 6.9 San Joaquin Valley, CA..................................... 3.2 St. Louis, MO-IL........................................... 2.6 Ventura County, CA......................................... 0.7 Washington, DC--Baltimore, DC, MD, VA MSA.................. 7.4 20 Areas................................................... 54.2 ------------------------------------------------------------------------ Areas with Pre-2007 Attainment Dates and Recent Concentrations within 10 percent of an Exceedance. ------------------------------------------------------------------------ Barnstable-Yarmouth, MA.................................... 0.2 Benton Harbor, MI.......................................... 0.2 Biloxi-Gulfport-Pascagoula, MS MSA......................... 0.4 Charleston, WV MSA......................................... 0.3 Cincinnati-Hamilton, OH-KY-IN.............................. 2.0 Cleveland-Akron, OH CMSA................................... 2.9 Grand Rapids-Muskegon-Holland, MI MSA...................... 1.1 Houma, LA.................................................. 0.2 Lake Charles, LA........................................... 0.2 New Orleans, LA MSA........................................ 1.3 Norfolk-Virginia Beach-Newport News, VA-NC MSA............. 1.6 Orlando, FL MSA............................................ 1.5 Pensacola, FL MSA.......................................... 0.4 Providence-Fall River-Warwick, RI-MA....................... 1.1 Tampa-St. Petersburg-Clearwater, FL MSA.................... 2.3 15 areas................................................... 15.7 ------------------------------------------------------------------------ Total Areas: 45........................................ Population: 128 ------------------------------------------------------------------------ a In order to determine the reliability of model predictions the Agency ran the ozone model for current ozone concentrations and compared those predictions with actual ozone levels recorded by ozone monitors. The results of the model's performance are presented in the RIA for this rule. [[Page 5017]] c. Public Health and Welfare Concerns from Prolonged and Repeated Exposures to Ozone A large body of scientific literature regarding health and welfare effects of ozone has associated health effects with certain patterns of ozone exposures that do not necessarily include any hourly ozone concentration above the 0.12 parts per million (ppm) level of the 1- hour NAAQS. The science indicates that there are health effects attributable to prolonged and repeated exposures to lower ozone concentrations. Studies of 6 to 8 hour exposures showed health effects from prolonged and repeated exposures at moderate levels of exertion to ozone concentrations as low as 0.08 ppm. Prolonged and repeated ozone concentrations at these levels are common in areas throughout the country, and are found in areas that are exceeding, and areas that are not exceeding, the 1-hour ozone standard. For example, 153 million people, or 87 percent of the total population in counties evaluated (176 million), lived in areas with 2 or more days with concentrations of 0.09 ppm or higher in 1998, including areas currently violating the 1-hour NAAQS. In the 2007, before the application of emission reductions resulting from this rule, we estimated that 116 million, or 93 percent of the total population considered in the analysis, are predicted to live in areas with at least 2 days with model-adjusted 8- hour average concentrations of 0.08 ppm or higher. By 2030, the number of people (139 million) and the relative percentage (91 percent) of the total population considered in the analysis is projected to grow significantly without reductions from this rule. Since prolonged exposures at moderate levels of ozone are more widespread than exceedances of the 1-hour ozone standard, and given the continuing nature of the 1-hour ozone problem described above, adverse health effects from this type of ozone exposure can reasonably be anticipated to occur in the future in the absence of this rule. Adverse welfare effects can also be anticipated, primarily from damage to vegetation. See the RIA for further details. Studies of acute health effects have shown transient pulmonary function responses, transient respiratory symptoms, effects on exercise performance, increased airway responsiveness, increased susceptibility to respiratory infection, increased hospital and emergency room visits, and transient pulmonary respiratory inflammation. Such acute health effects have been observed following prolonged exposures at moderate levels of exertion at concentrations of ozone well below the current standard of 0.12 ppm. The effects are more pronounced at concentrations above 0.09 ppm, affecting more subjects or having a greater effect on a given subject in terms of functional changes or symptoms. A more detailed discussion may be found in the RIA. With regard to chronic health effects, the collective data have many ambiguities, but provide suggestive evidence of chronic effects in humans. There is a biologically plausible basis for considering the possibility that repeated inflammation associated with exposure to ozone over a lifetime, as can occur with prolonged exposure to moderate ozone levels below peak levels, may result in sufficient damage to respiratory tissue that individuals later in life may experience a reduced quality of life, although such relationships remain highly uncertain. Ozone has many welfare effects, with damage to plants being of most concern. Plant damage affects crop yields, forestry production, and ornamentals. The adverse effect of ozone on forests and other natural vegetation can in turn cause damage to associated ecosystems, with additional resulting economic losses, as well as aesthetic impacts which may not be fully quantifiable in economic terms. Ozone concentrations of 0.10 ppm can be phytotoxic to a large number of plant species, and can produce acute injury and reduced crop yield and biomass production. Ozone concentrations at or below 0.10 ppm have the potential over a longer duration of creating chronic stress on vegetation that can result in reduced plant growth and yield, shifts in competitive advantages in mixed populations, decreased vigor, and injury from other environmental stresses. Section 202(a) provides EPA with authority to promulgate standards applicable to motor vehicle emissions that ``in the Administrator's judgment, cause or contribute to air pollution reasonably anticipated to endanger public health and welfare.'' The evidence in the RIA regarding the occurrence of adverse health effects due to prolonged and repeated exposure to ozone concentrations in the range discussed above, and regarding the populations that are expected to receive exposures at these levels, along with the welfare effects described above, supports a conclusion that emissions of NOX and VOC from heavy-duty vehicles in 2007 and later will be contributing to a national air pollution problem that warrants regulatory action under section 202(a) of the Act. 3. Particulate Matter a. Health and Welfare Effects 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. All particles equal to and less than 10 microns are called PM10. Fine particles can be generally defined as those particles with an aerodynamic diameter of 2.5 microns or less (also known as PM2.5), and coarse fraction particles are those particles with an aerodynamic diameter greater than 2.5 microns, but equal to or less than a nominal 10 microns. The health and environmental effects of PM are strongly related to the size of the particles. 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, nitrogen oxides, or organic compounds. Fine particles are generally composed of sulfate, nitrate, chloride and ammonium compounds; organic and elemental carbon; and metals. 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 and are often dominated by resuspended dusts and crustal material from paved or unpaved roads or from construction, farming, and mining activities. 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. Diesel particles are a component of both coarse and fine PM, but fall mostly in the fine and ultrafine size range.25 Diesel PM contains small quantities of numerous mutagenic and carcinogenic compounds. While representing a very small portion (less than one percent) of the national emissions of metals, and a small portion of diesel particulate matter (one to five percent), we note that several toxic trace metals of potential [[Page 5018]] toxicological significance are also emitted by diesel engines including chromium, manganese, mercury and nickel. In addition, small amounts of dioxins have been measured in diesel exhaust, some of which may partition into the particle phase, though the impact of these emissions on human health is not clear. --------------------------------------------------------------------------- \25\ Fine particulate matter includes particles with a diameter less than 2.5 micrometers. Ultrafine particulate matter include particles with a diameter less than 100 nanometers. --------------------------------------------------------------------------- Particulate matter, like ozone, has been linked to a range of serious respiratory health problems. Scientific studies suggest a likely causal role of ambient particulate matter (which is attributable to a number of sources including diesel) in contributing to a series of health effects. The key health effects categories associated with ambient particulate matter include premature mortality, aggravation of respiratory and cardiovascular disease (as indicated by increased hospital admissions and emergency room visits, school absences, work loss days, and restricted activity days), aggravated asthma, acute respiratory symptoms, including aggravated coughing and difficult or painful breathing, chronic bronchitis, and decreased lung function that can be experienced as shortness of breath. Observable human noncancer health effects associated with exposure to diesel PM include some of the same health effects reported for ambient PM such as respiratory symptoms (cough, labored breathing, chest tightness, wheezing), and chronic respiratory disease (cough, phlegm, chronic bronchitis and suggestive evidence for decreases in pulmonary function). Symptoms of immunological effects such as wheezing and increased allergenicity are also seen. Studies in rodents, especially rats, show the potential for human inflammatory effects in the lung and consequential lung tissue damage from chronic diesel exhaust inhalation exposure. Both fine and coarse particles can accumulate in the respiratory system. Exposure to fine particles is most closely associated with such health effects as premature mortality or hospital admissions for cardiopulmonary disease. For additional information on health effects, see the RIA. PM also causes damage to materials and soiling of commonly used building materials and culturally important items such as statutes and works of art. It is a major cause of substantial visibility impairment in many parts of the U.S. Heavy-duty vehicles contribute to particle formation through a number of pollutants. The contribution to PM fine varies by region of the country. Sulfate plays a major role in the composition of fine particulate across the country, but typically makes up over half the fine particles found in the Eastern United States. Organic carbon accounts for a large portion of fine particle mass, with a slightly higher fraction in the west. Diesel engines are the principal source of elemental carbon, which makes up about 5-6 percent of particle mass. Nationally, nitrate plays a relatively small role in the make up of fine particles, but ammonium nitrate plays a far larger role in southern California. Ammonium nitrate-formed secondarily from NOX and ammonia emissions--is one of the most significant components of particulate matter pollution in California. During some of the worst episodes of elevated particle levels in the South Coast, ammonium nitrate can account for about 65-75 percent of the PM2.5 mass. Reducing ammonium nitrate through controls on NOX sources is a critical part of California's particulate matter strategy. Nationally, the standards finalized in this rule will significantly reduce HDV emissions of SOX, NOX, VOCs and elemental carbon, and thus contribute to reductions in ambient concentrations of PM10 and PM2.5. b. Attainment and Maintenance of the PM10 NAAQS Under the CAA, we are to regulate HDV emissions if they contribute to air pollution that can reasonably be anticipated to endanger public health and welfare. We have already addressed the question of what concentration patterns of PM endanger public health, in setting the NAAQS for PM10 in 1987. The PM NAAQS were revised in 1997, largely by adding new standards for fine particles (PM2.5) and modifying the form of the daily PM10 standard. On judicial review, the revised standards were remanded for further proceedings, and the revised PM10 standards were vacated. The Supreme Court is currently reviewing that decision. Oral arguments were held on November 7, 2000 and a decision by the Court is expected in 2001. Pending final resolution of the litigation, the 1987 PM10 standard is the applicable NAAQS for PM10. Commenters questioned the need for additional PM10 reductions in order to achieve attainment with the PM10 NAAQS, and questioned the Agency's statement that, unlike ozone, PM10 emissions are projected to increase in the future. Commenters are correct that significant progress has occurred over the last decade,26 but the Agency's statement was based on projected PM10 inventory increases in the future between 1996 and 2030. During this period, inventory trends for current PM10 nonattainment areas, or those with concentrations within 10 percent of the standard, are predicted to increase significantly. For example, from 1996 to 2030, increases are predicted in Clark County (Las Vegas) of 41 percent, Harris County (Houston) of 37 percent, and Phoenix of 24 percent. A more detailed discussion is provided in the RIA. --------------------------------------------------------------------------- \26\ Ambient concentrations of PM10 and PM10 emissions have declined over the last ten years by 25 percent and 19 percent, respectively. National Air Quality and Emissions Trends Report, 1998, US EPA, March, 2000. --------------------------------------------------------------------------- i. Current PM10 Nonattainment The most recent PM10 monitoring data indicates that 14 designated PM10 nonattainment areas with a projected population of 23 million violated the PM10 NAAQS in the period 1997-1999. Table II.B-3 lists the 14 areas, and also indicates the PM10 nonattainment classification and 1999 projected population for each PM10 nonattainment area. The projected population in 1999 was based on 1990 population figures which were then increased by the amount of population growth in the relevant county from 1990 to 1999. Table II.B-3.--PM10 Nonattainment Areas Violating the PM10 NAAQS in 1997- 99 ------------------------------------------------------------------------ 1999 Population Area Classification (projected, in millions) ------------------------------------------------------------------------ Hayden/Miami, AZ.................. Moderate............ 0.004 Phoenix, AZ....................... Serious............. 2.977 Nogales, AZ....................... Moderate............ 0.025 San Joaquin Valley, CA............ Serious............. 3.214 Imperial Valley, CA............... Moderate............ 0.122 [[Page 5019]] Owens Valley, CA.................. Serious............. 0.018 Searles Valley, CA................ Moderate............ 0.029 Coachella Valley, CA.............. Serious............. 0.239 South Coast Air Basin............. Serious............. 14.352 Las Vegas, NV..................... Serious............. 1.200 Reno, NV.......................... Moderate............ 0.320 Anthony, NM b..................... Moderate............ 0.003 El Paso, TX a..................... Moderate............ 0.611 Wallula, WA b..................... Moderate............ 0.052 Total Areas: 14............. .................... 23.167 ------------------------------------------------------------------------ a EPA has determined that continuing PM10 nonattainment in El Paso, TX is attributable to international transport under section 179(B). b The violation in this area has been determined to be attributable to natural events under section 188(f) of the Act. In addition to the 14 PM10 nonattainment areas that are currently violating the PM10 NAAQS, there are 25 unclassifiable areas that have recently recorded ambient concentrations of PM10 above the PM10 NAAQS. EPA adopted a policy in 1996 that allows areas with PM10 exceedances that are attributable to natural events to retain their designation as un