OLR Research Report

January 23, 2004




By: Paul Frisman, Associate Analyst

You asked (1) how many states have adopted California's motor vehicle emissions standards, (2) the differences between the California standards and those of the U.S. Environmental Protection Agency (EPA), (3) motor vehicle manufacturers' response to the California standards, and (4) how adopting the California standards would affect Connecticut air quality.


Besides California, four states (New York, Massachusetts, Vermont and New Jersey) have adopted California's motor vehicle emission standards. Maine has adopted a portion of the California standards. There are a number of differences between the California and federal standards, the most significant of which is California's requirement that 10% of a motor vehicle fleet comprise zero emission vehicles or their equivalent. Other differences include the pollutants on which the programs focus, and different evaporative emission standards.

Motor vehicle manufacturers say the benefits of the California standards over the federal standards are slight, and not worth the very high costs they say are involved. Several studies, cited below, say adoption of the California standards will greatly improve Connecticut air quality. State law authorizes the Department of Environmental Protection (DEP) commissioner to incorporate California motor vehicle emission standards by reference in state regulations.


All new cars sold in the U.S. must comply with emission standards set either by the EPA or California. (California is the only state with federal authority to devise its own standards). New York, Massachusetts, Maine, Vermont and most recently New Jersey have adopted the California standards. The New Jersey legislature voted to adopt the California standards on January 12, 2004. Maine has not adopted the Zero-Emission Vehicle (ZEV) component of the LEV II standards.

California initially implemented its Low Emission Vehicle (LEV) program in the 1990s. Connecticut has the option of adopting the second phase of the California program, known as LEV II, beginning in the 2007 model year. If Connecticut chooses not to adopt the California standards, it must comply with the second phase of the EPA program, known as Tier 2. Motor vehicles are subject to Tier 2 requirements beginning in 2004. Full implementation of LEV II occurs in 2007, and of Tier 2 in 2009.

LEV II and Tier 2 are similar in that they each require a manufacturer's vehicle fleet to meet stricter average emissions standards for both gasoline and diesel vehicles, apply passenger car standards to most sport utility vehicles (SUVs) and light trucks, and place tighter controls on evaporative emissions from vehicles' fuel tanks and fuel systems, as well as their exhaust systems.

The Tier 2 program initially classifies vehicles into 11 “bins” which set varying pollution standards. Car makers must offset the production of vehicles from the higher-polluting “bins” with production of cleaner vehicles to meet the fleet-wide average emission standard for nitrogen oxide (NOx). Under LEV II manufacturers can certify vehicles in one of four categories, depending on their emissions. These are: LEV (low emission vehicles), ULEV (ultra low-emission); SULEV (super ultra low-emission) and ZEV (zero emission).


LEV II's Zero Emission Vehicle Component

The largest difference between the programs is LEV II's so-called Zero-Emission Vehicle (ZEV) component. This requires that a certain percentage of a manufacturer's vehicle fleet achieve even lower emissions than LEV II otherwise requires through the use of advanced technology. Ten percent of a manufacturers vehicle fleet must meet the ZEV requirement between 2005 and 2009. By 2018, 16% of the manufacturer's fleet must be ZEVs. Although initially intended to require the manufacture of battery-powered vehicles, this provision has been amended to give manufacturers ZEV credit for conventional gasoline vehicles that meet certain emissions and durability requirements, and for vehicles that achieve near zero emissions through the use of alternative fuels, electric or fuel cell technology, or combinations of these technologies. ZEV vehicles also must meet more stringent evaporative emission requirements than other LEV II vehicles. Advocates say this provision of LEV II will promote inherently cleaner technology and prevent, rather than mitigate, pollution. Also, ZEV vehicles emit much less greenhouse gas, such as carbon dioxide, than conventional vehicles. Greenhouse gases contribute to global warming, which is believed to have a wide range of harmful health and ecological effects.

Focus on Different Pollutants

LEV II sets progressively stricter emission limits for volatile organic compounds (VOCs). Tier 2 instead concentrates on a stricter fleet wide average for NOx. VOCs and NOx combine with sunlight to form ozone, a principal component of smog. Ozone can cause respiratory problems, aggravate asthma, and damage the lining of the lungs. VOCs include many toxic chemicals, such as benzene and formaldehyde.

According to “The Drive for Cleaner Air in Connecticut,” a September 2003 report by the Connecticut Fund for the Environment (CFE), a nonprofit environmental organization, the LEV II program requires manufacturers to achieve a declining fleet-wide average for VOCs, while the Tier 2 VOCs standard remains constant.

“Comparing the Emissions Reductions of the LEV II Program to the Tier 2 Program,” prepared in October 2003 for the Northeast States for Coordinated Air Use Management (NESCAUM), states that there is only a minimal difference between the two programs with respect to NOx. NESCAUM is an interstate association of state air quality agencies from the six New England states, New York and New Jersey. DEP is a member of NESCAUM.

Different Evaporative Emissions Standards

Evaporative emissions escape from a motor vehicle's fuel tank or fuel system rather than from its tailpipe. CFE says these emissions account for about half of VOC emissions. According to CFE and NESCAUM, LEV II evaporative emission standards are more stringent than those under Tier 2.

Different Diesel Requirements

The CFE report states that Tier 2 particulate matter (soot) standards would allow diesel-fueled vehicles to release about twice as much particulate matter as they would under LEV II.

Sulfur Levels

Tier 2 regulations reduce the level of sulfur in gasoline. LEV II does not contain fuel requirements, but federal low-sulfur fuel requirement would apply.


The Alliance of Automobile Manufacturers (AAM), a trade association of nine foreign and domestic motor vehicle manufacturers, favors Tier 2. It says Tier 2 will provide the same benefits as LEV II at much less cost, and will allow car makers much more flexibility in meeting the standards. AAM states that it will cost Connecticut between $8 million and $18.6 million to implement the ZEV portion of the LEV II program, and that LEV II will not provide much more air quality benefit than would Tier 2. AAM submitted its comments (attached) on December 4, 2003 to the Connecticut Climate Change Stakeholder Dialogue, which was formulating its recommendations for the Governor's Steering Committee on Climate Change. (The stakeholders group issued its recommendations in a January 2004 report.)



The NESCAUM report finds that while both the LEV II and Tier 2 programs would reduce vehicle exhaust emissions by an additional 90% or more over the next 20 years, LEV II would provide more benefits than Tier 2 because of its ZEV requirement and its stricter evaporative and tailpipe emissions standards.

NESCAUM calculated daily emission reductions only or Massachusetts, New York and Vermont, but said similar benefits could be expected in other states adopting LEV II.

Specifically, the NESCAUM analysis found LEV II resulted in additional reductions in light-duty vehicle VOC emissions of 4% in 2010 and 16% in 2020 compared to Tier 2. These benefits were considered particularly significant with respect to toxic VOC emissions that are either known human carcinogens (benzene) or probable carcinogens (formaldehyde and 1,3-butadiene). According to the NESCAUM report, LEV II would reduce toxic vehicle emissions by an additional 25% over Tier 2 in 2020.

However, the report notes that EPA has reached different conclusions in two different reports. EPA first predicted that LEV II would provide additional VOC reductions of 21% compared to Tier 2, but in a subsequent report predicted a much smaller LEV II benefit of 5%. The NESCAUM report says its findings are closer to those of the earlier EPA report.

According to NESCAUM, an additional reason to adopt the LEV II standards is California's frequent update of its emissions standards. States that adopt LEV II would benefit from California progressively tightening its requirements, while EPA may not change the Tier 2 requirements for another decade or more.

The NESCAUM analysis also found that LEV II gave carbon dioxide reduction benefits of about 3% in 2020 compared to Tier 2, primarily as a result of the ZEV component.

CFE Report

According to CFE's analysis, LEV II would reduce VOCs by 1,862 tons and NOx by 640 more tons than Tier 2 in 2025. Cars and light trucks would generate 137 fewer tons of the known carcinogen benzene, and the probable carcinogens formaldehyde, 1,3-butadiene, and acetaldehyde than would be emitted under Tier 2 in 2025. CFE states that there would be 12% fewer cancers attributable to these four toxic chemicals in 2025 for LEV II compared to Tier 2.

CFE found that meeting LEV II's ZEV requirements would result in between 2.2% and 4.2% less greenhouse gas emissions than under Tier 2, depending on how aggressive a strategy is used to meet the ZEV requirements. (A more aggressive strategy, for example, would introduce hybrid technology to heavier truck classes.)

Alliance of Automobile Manufacturers

According to an AAM study, the difference in the generation of greenhouse gases between LEV II and Tier 2 would, at best, not amount to 1% until 2020, 13 years after implementation. AAM also states that the Tier 2 program will provide virtually identical benefits to LEV II in terms of toxic chemicals.

AAM says the cost of implementing the California standards will outweigh its benefits, particularly when it comes to the costs of pure ZEV vehicles. AAM states that it would cost Connecticut between $2.3 million and $13 million in customer incentives, such as grants, to encourage the purchase of expensive ZEV vehicles, such as battery and fuel cell powered vehicles. Connecticut would also need to hire additional staff and build infrastructure to administer and support the program, AAM said. We have attached the AAM analysis.

Recommendations to the Governor's Steering Committee on Climate Change

According to the Connecticut Climate Change Stakeholder Dialogue's Recommendations to the Governor's Steering Committee, benefits of adopting LEV II would include estimated greenhouse gas emission reductions of the equivalent of 0.04 million metric tons of carbon dioxide in 2010 and 0.47 million metric tons of carbon dioxide in 2020. It said adoption of LEV II standards also would reduce toxic pollutants by 104 tons in 2020.

The stakeholders' group also recommended a package of policies and measures to reduce greenhouse gas emission rates by 33% by 2020. We have attached a copy of those recommendations.