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Redistributed as a Service of the National Library for the Environment* |
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Air Quality and Vehicle Emission
Standards: David M. Bearden January 4, 1999 RL30005
Summary List of Tables Summary Despite pollution controls currently in place, areas in many states have yet to attain the National Ambient Air Ouality Standard (NAAQS) for ozone. While further reductions in emissions from motor vehicles might assist states in achieving compliance, the Clean Air Act prevents the Environmental Protection Agency (EPA) from introducing stricter vehicle emission standards sooner than model year (MY) 2004. To achieve additional emission reductions prior to this time, EPA has cooperated with numerous states and 23 vehicle manufacturers to develop a voluntary National Low Emission Vehicle (LEV) Program. Manufacturers have agreed to produce cleaner vehicles for sale in eight Northeastern states and the District of Columbia beginning in MY1999 and nationwide in MY2OO1. While manufacturers have voluntarily agreed to participate, the National LEV program arose out of past attempts by numerous states and EPA to mandate stricter standards in the Northeast and as a result of subsequent litigation challenging their authority to do so. The National LEV program adopts California's low emission standards and testing procedures for non-methane organic gases (NMOG), nitrogen oxides (NO2) carbon monoxide (CO), particulate matter (PM), and formaldehyde (HCHO). Manufacturers will have the option of certifying their vehicles under different categories subject to increasingly stringent standards and will have considerable flexibility in demonstrating compliance by using fleet emission averages and trading emission credits. EPA estimates that the average incremental cost of each vehicle certified under the program's low emission standards will be $76 more than a higher emitting vehicle that meets current federal standards. Based on projections of vehicle sales nationwide, EPA estimates that the total cost of the program would be $950 million annually. The program focuses on controlling the level of ozone precursors by requiring a 70% reduction in emissions of NMOG and a 50% reduction in emissions of NO2, which also could help to reduce concentrations of fine particulates. The program also would provide modest reductions in emissions of CO, PM, and HCHO. However, actual air quality benefits will depend to a large extent on whether certified vehicles operate as cleanly in actual use as they do under test conditions. Two related regulatory issues could play significant roles in determining the extent to which the National LEV program is able to reduce actual emissions and help states improve air quality. First, high sulfur levels in commercial gasoline could diminish the effectiveness of low emission technologies. Second, light trucks are not regulated as strictly as passenger automobiles. The increasing market share of light trucks could alter the composition of the vehicle fleet significantly enough to increase total emissions and offset the sharper reductions from passenger automobiles. While the National LEV program will regulate emissions from new vehicles more strictly than the current federal standards, it is a partial attempt at introducing cleaner vehicles nationwide because it leaves the two larger regulatory issues of gasoline sulfur levels and higher emissions from light trucks open for further debate. The Motor Vehicle Air Pollution Control Act of 1965 (P.L. 89-272) required the federal government to establish standards that limit the tailpipe emissions of each new vehicle manufactured for sale in the United States. While vehicle emission standards have become more stringent with subsequent amendments to the Clean Air Act in 1967, 1970, 1977, and 1990, the number of vehicle miles traveled has increased substantially from 588 billion in 1960 to over 1.5 trillion in 1995. 1 The rise in travel has offset a significant portion of the progress made in emission controls, and as a result, motor vehicles continue to be major sources of air pollution. The Environmental Protection Agency (EPA) reports that in 1996 on4oad vehicles accounted for roughly 60% of total emissions of carbon monoxide (CO) in the United States, about 31% of nitrogen oxides (NOx), nearly 30% of volatile organic compounds (VOCs), and approximately 8% of particulate matter (PM). 2 NOx and VOCs pose particular obstacles to improving air quality because they are the primary contributors to the formation of groundlevel ozone. 3 Despite pollution controls currently in place, areas in many states have yet to attain the National Ambient Air Quality Standards (NAAQS). 4 Attainment of the standard for ozone has been a persisting problem especially among the Northeastern states primarily due to high concentrations of the ozone precursors NOx and VOCs. While further reductions in emissions of these pollutants from motor vehicles might assist Northeastern and other states in complying with the ozone standard, the Clean Air Act prevents EPA from imposing more stringent emission standards on vehicle manufacturers sooner than model year (MY) 2004. To achieve additional emission reductions prior to this time, EPA has cooperated with numerous states and 23 vehicle manufacturers to develop a voluntary National Low Emission Vehicle (LEV) Program. 5 Manufacturers have agreed to produce cleaner vehicles for sale in eight Northeastern states and the District of Columbia beginning in MY1999 and nationwide in MY2OO1. 6 The program uses the same low emission standards and testing procedures already adopted in California, New York, Massachusetts, Vermont, and Maine. The main incentive for manufacturers to participate is that they will be able to produce a single fleet of vehicles for sale nationwide rather than having to produce a separate fleet to meet stricter requirements in only a few states. While manufacturers voluntarily have agreed to produce cleaner vehicles nationwide, the National LEV program arose out of attempts by numerous states and EPA to mandate stricter standards in the Northeast and as a result of subsequent litigation challenging their authority to do so. In February 1994, the Ozone Transport Commission (OTC), which represents 12 Northeastern states and the District of Columbia, recommended that EPA require the adoption of California's LEV program in the Northeast to help improve air quality. 7 Subsequently, EPA issued a rule in January 1995 to implement the OTC's recommendation. 8 New York, Massachusetts, Vermont, and Maine have adopted California's LEV program. However, Virginia and several vehicle manufacturers legally challenged EPA's authority to mandate stricter standards. A U.S. Court of Appeals ruled that EPA does not have the authority under the Clean Air Act to impose stricter standards for new vehicles prior to MY2004 even if air quality problems warranted such action. 9 During these events, EPA held ongoing discussions with states and manufacturers to develop an alternative to mandating tighter standards, which resulted in an agreement to establish the National LEV program based on California's low emission requirements. In addition to challenging EPA's authority to mandate stricter standards, manufacturers also were concerned about the possibility of many states adopting California's sales target for zero emission vehicles (ZEVs). Industry generally views ZEV sales targets as unrealistic because the costs of electric and fuel cell technologies necessary to eliminate all emissions remain significantly higher than conventional gasoline and diesel engines and the market for vehicles using these technologies is not yet established. As a means to encourage the participation of manufacturers, the National LEV program does not include ZEV sales targets. This report provides background information on federal emission standards for motor vehicles under the Clean Air Act and stricter standards originally developed to address the severity of air quality problems in California, explains low emission standards and flexible compliance mechanisms to which states and manufacturers have voluntarily agreed under the National LEV Program, discusses EPA's estimates of air quality benefits and costs, and examines regulatory issues related to its implementation including sulfur levels in gasoline and the relative stringency of emission standards for light trucks.Current Regulation of Vehicle Emissions The Clean Air Act Amendments of 1990 (P.L. 101-549) established more stringent federal emission standards for all new vehicles manufactured for sale in the United States. The current standards, referred to as Tier 1, replaced less stringent requirements previously introduced under the Clean Air Act Amendments of 1977 (P.L. 95-95). While the Clean Air Act generally prohibits individual states from enforcing vehicle emission standards that are different from the federal ones, it provides an exception that allows California to develop stricter requirements to help address serious air quality problems in many of that state's metropolitan areas. The Tier 1 standards and California's more stringent requirements are discussed below. Tier 1 Standards The Tier 1 standards regulate emissions of non-methane hydrocarbons (NMHC), CO, NOx, and PM from each new vehicle manufactured for sale in the United States. 10 To reduce the regulatory burden on manufacturers, the standards were phased in gradually over three years beginning in MY1994. Passenger automobiles and smaller light trucks weighing up to 3,750 pounds are subject to more stringent standards than larger light trucks (including many sport-utility vehicles and minivans) weighing between 3,751 and 5,750 pounds. Heavier duty light trucks weighing more than 5,750 pounds are subject to the least stringent standards. In addition, each weight category is subject to separate standards for different intervals of vehicle use: an intermediate operational life of 5 years or 50,000 miles and a full operational life of 10 years or 100,000 miles (11 years or 120,000 miles for light tucks weighing more than 5,750 pounds). Section 202 of the Clean Air Act requires EPA to determine whether air quality needs warrant revisions to the Tier 1 standards to achieve further reductions in emissions. However, more stringent Tier 2 standards could not become effective prior to MY2004. EPA submitted its Tier 2 study to Congress in August 1998, and if it deems necessary, is required by the Clean Air Act to propose such standards by December 31, 1999 through a rulemaking process. 11 California's Low Emission Standards EPA approved California's LEV program in January 1993 with authority provided under Section 209 of the Clean Air Act. 12 The program became effective in MY1994 and requires manufacturers to comply with low emission standards for vehicles produced for sale in the state. It retains the basic structure of the Tier 1 requirements, under which passenger automobiles and light trucks are subject to separate sets of standards according to vehicle weight and amount of use. In addition to stricter standards, California's program differs from the Tier 1 requirements in three ways. First, it replaced the testing procedure for NMHC with a test for non-methane organic gases (NMOG) that more accurately measures the level of hydrocarbons, and it added a new standard for formaldehyde (HCHO), a carcinogen. Second, manufacturers must certify each vehicle under one of five categories: California Tier 1 vehicles, transitional low emission vehicles (TLEVs), low emission vehicles (LEVs), ultra low emission vehicles (ULEVs), or ZEVs. However, they have the flexibility to demonstrate compliance by using fleet emission averages instead of certifying each vehicle according to the same stringency. Third, the program requires that ZEVs comprise 10% of total vehicle sales in the state by MY2003. On November 5, 1998, the California Air Resources Board, a state agency, finalized revisions to its LEV program (LEV II) that will become effective in MY2004 and increase the stringency of that state's low emission standards beyond their current level. 13 California's current LEV I standards will remain in effect through MY2003.National Low Emission Vehicle Program The National LEV program adopts California's current LEV I standards for NMOG, NOx, CO, PM, and HCHO. 14 It also incorporates flexible compliance mechanisms that allow manufacturers to use fleet emission averages instead of certifying each vehicle according to the same stringency. The program focuses on controlling the formation of ozone by requiring a 70% reduction NMOG emissions and a 50% reduction in NOx emissions. The standards require much fewer reductions in CO emissions primarily because ambient concentrations of this pollutant have been declining steadily since 1987. Gasoline-powered vehicles are not significant sources of PM, and the low emission standard for this pollutant is limited to diesel vehicles. The standard for HCHO would provide additional air quality benefits by reducing carcinogen levels. However, certified vehicles may emit greater quantities of pollutants in actual use than the program's standards indicate if the regulatory issues of gasoline sulfur levels and the relative stringency of emission standards for light trucks are not addressed, both of which are discussed later in this report. Specific requirements of the program and EPA's estimates of air quality benefits and costs are explained below. Certification Standards Similar to California's LEV program, manufacturers must certify each vehicle according to one of four different categories subject to increasingly stringent emission standards: federal Tier 1, TLEVs, LEVs, or ULBVs. While the National LEV program does not include California's ZEV sales target, manufacturers also can certif~ their vehicles as ZEVs and receive credit for their air quality benefits. Relative to the NMOG standard, vehicles certified as TLEVs will be 50% cleaner than Tier 1 vehicles, those certified as LEVs will be 70% cleaner, and those certified as ULEVs will be 85% cleaner. Like the Tier 1 and California standards, passenger automobiles and smaller light truclcs weighing up to 3,750 pounds are subject to stricter standards than larger light trucks weighing between 3,751 and 5,750 pounds. (Refer to table.) Light trucks weighing more than 5,750 pounds remain subject to the less stringent Tier 1 standards, as there are no low emission standards for these heavier vehicles. In addition, certified vehicles also must other low emission standards for the Supplemental Federal Test Procedure which measures emissions during high speed acceleration, high speed driving, and air conditioning use. Endnotes 1 Department of Transportation. Bureau of Transportation Statistics. FY1997 National Transportation Statistics. p.222. 2 EPA. Office of Air Quality Planning and Standards. 1996 National Air Quality and Emissions Trends Report January 1998. p.82-86. 3 Vehicles do not directly emit ozone. Rather, NOx and VOCs produce ozone when they chemically react in the presence of sunlight. vehicles emit VOCs primarily in the form of hydrocarbons (HC). 4 The NAAQs establish safe ambient levels for carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter, and sulfur dioxide. States must develop plans for attaining the standards in areas that have exceeded allowable levels and for maintairling air quality in areas that once were in nonattainment but have since met the standards For flirther discussion, refer to CRS Issue Brief 97007, Clean Air Act Issues, by James McCarthy. 5 American Honda Motor Company, American Suzuki Motor Corporation, BMW of North America, Chrysler Corporation, Fiat Auto U.S.A., Ford Motor Company, General Motors Corporation, Hyundai Motor America, Isuzu Motors America, Jaguar Motors Ltd., Kia Motors America, Land Rover North America, Mazda ~orth America), Mercedes-Benz of North America, Mitsubishi Motor Sales of America, Nissan North America, Porsche Cars of North America, Rolls-Royce Motor Cars, Saab Cars USA, Subarn of America, Toyota Motor Sales, U.S.A., Volkswagen of America, and Volvo North America Corporation. 6 The eight Northeastern states include: Connecticut, Delaware, Maryland, New Hampshire, New Jersey, Pennsylvania, Rhode Island, and Virginia. 7 Section 184 of the Clean Air Act established an interstate ozone transport region in the Northeast, which includes Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia, and the District of Columbia. The Act also directed EPA to establish a commission composed of representatives from these states. The commission's purpose is to determine the degree to which the transport of ozone and its precursors occurs throughout the region, assess strategies for mitigating interstate ozone transport, and recommend measures to assist states in the region with attaining the federal air quality standard for ozone. 8 EPA. Federal Register. January 24, 1995. p.4712-4739. 9 D.C. Circuit Court of Appeals. VIrginia vs. EPA. No 95-1163. March 11, 1997. 10 Clean Air Act, Section 202. 42 U.S.C. 7521. 11 EPA. Office of Air and Radiation. Tier 2 Report to Congress. July 1998. 55 p. 12 EPA. Federal Register. January 13, 1993. p.4166. Section 209 of the Clean Air Act allows EPA to grant a waiver to California for adopting vehicle emission standards that are more stringent than the federal ones. Section 177 permits other states with serious air quality problems to adopt stricter standards if they are identical to California's. 13 For information on California's new LEV II standards, refer to the California Air Resources Board Home Page at http://www.arb.ca.gov 14 EPA. Federal Register. June 6, 1997. p.31192-31270. 15 Although the National LEV program does not include a standard for benzene, EPA expects that the low emission technologies used to achieve the certification standards also would reduce emissions of this pollutant. 16 EPA. Federal Register. June 6, 1997. p.31195-31196. 17 EPA. Office of Air Quality Planning and Standards. 1996 National Air Quality and Emissions Trends Report. January 1998. p.84-85. EPA estimates that in 1996 stationary and mobile sources in the United States emitted 23.4 million tons of NOx, 19.1 million tons of VOCs, and 3.3 million tons of PM, yielding adaily emissions average of roughly 64,000 tons for NOx, over 52,000 tons for VOCs, and approximately 9,000 tons for PM. 18 EPA. Federal Register. June 6, 1997. p. 31197 ... |
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