Office of Transportation and Air Quality

EPA-420-F-14-009

March 2014

EPA Sets Tier 3 Motor Vehicle 

Emission and Fuel Standards

The U.S. Environmental Protection Agency (EPA) is finalizing an 

important rule designed to reduce air pollution from passenger 

cars and trucks. Starting in 2017, Tier 3 sets new vehicle emissions 

standards and lowers the sulfur content of gasoline, considering the 

vehicle and its fuel as an integrated system. 

 The Tier 3 vehicle standards reduce both tailpipe and evaporative emissions 

from passenger cars, light-duty trucks, medium-duty passenger vehicles, and 

some heavy-duty vehicles. 

 The Tier 3 gasoline sulfur standard will make emission control systems more 

effective for both existing and new vehicles, and will enable more stringent 

vehicle emissions standards. Removing sulfur allows the vehicle’s catalyst to 

work more efficiently. Lower sulfur gasoline also facilitates the development 

of some lower-cost technologies to improve fuel economy and reduce greenhouse gas (GHG) emissions, which reduces gasoline consumption and saves 

consumers money.

 The tailpipe standards include different phase-in schedules that vary by 

vehicle class but generally phase in between model years 2017 and 2025. In 

addition to the gradual phase-in schedules, other flexibilities include credits 

for early compliance and the ability to offset some higher-emitting vehicles 

with extra-clean models. 

	The fuel sulfur standards include an averaging, banking, and trading (ABT) 

program that will allow refiners and importers to spread out their investments 

through an early credit program and rely on ongoing nationwide averaging to 

meet the sulfur standard. EPA is also finalizing flexibilities such as the ability 

to carry over credits from Tier 2 to Tier 3 and hardship provisions for extenuating circumstances, as well as flexibility provisions for small businesses (small 

manufacturers of Tier 3 vehicles and small refiners), small volume manufacRegulatory Announcement

turers, and small volume refineries.
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	The Tier 3 program continues the successful transition that began with EPA’s Tier 2 program, finalized in 2000, in which EPA treated vehicles and fuels as a system to reduce 

both gasoline sulfur and vehicle emissions. While there were claims at the time that the 

program would cause fuel prices to increase far in excess of EPA’s estimates and would 

result in closures and fuel supply shortages, the Tier 2 program was a success and resulted 

in gasoline sulfur reductions of up to 90 percent and enabled the use of new emission 

control technologies in cars and trucks with no serious negative impacts on the refining 

industry. EPA’s Clean Diesel Program similarly utilized a systems approach to reducing 

sulfur emissions from diesel fuels and enabling cleaner diesel technologies with the 

Highway Diesel Rule (finalized in 2001) and the Nonroad Diesel Rule (finalized in 2004) 

again with no serious negative impacts. Now that the U.S. refining industry routinely 

produces lower sulfur fuel products, new market opportunities for international fuel 

exports have opened up. 

	EPA is finalizing the Tier 3 program largely as proposed. EPA received a large number 

and wide range of comments on the proposed rule, and the final Tier 3 program is based 

both on this extensive public input and updated analyses of the rule’s impacts. EPA 

sought comment on the level of the per-gallon sulfur cap (which applies in addition to 

the annual average), and has decided to maintain the per-gallon caps at existing levels. 

EPA is also finalizing an ethanol content of 10 percent (E10) for emissions test gasoline 

(as opposed to the proposed 15 percent ethanol (E15) test fuel). 

Benefits and Costs of the Rule

These Tier 3 standards will address public health issues that exist currently and are projected to 

continue in the future as requested in a May 21, 2010 Presidential memorandum.

	Over 149 million Americans are currently experiencing unhealthy levels of air pollution 

which are linked with adverse health impacts such as hospital admissions, emergency 

room visits, and premature mortality. Motor vehicles are a particularly important source 

of exposure to air pollution, especially in urban areas. 

	The vehicle emission standards combined with the reduction of gasoline sulfur content 

will significantly reduce motor vehicle emissions, including nitrogen oxides (NOX), 

volatile organic compounds (VOC), direct particulate matter (PM2.5), carbon monoxide 

(CO) and air toxics. 

	Compared to current standards, the non-methane organic gases (NMOG) and nitrogen 

oxides (NOX), presented as NMOG+NOX, tailpipe standards for light-duty vehicles 

represent approximately an 80% reduction from today’s fleet average and a 70% 

reduction in per-vehicle particulate matter (PM) standards. The heavy-duty tailpipe 

standards represent about a 60% reduction in both fleet average NMOG+NOX and pervehicle PM standards. EPA is also extending the regulatory useful life period during 

which the standards apply from 120,000 miles to 150,000 miles.
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	Under the final Tier 3 program, federal gasoline will not contain more than 10 parts per 

million (ppm) of sulfur on an annual average basis by January 1, 2017. EPA is also finalizing standards that maintain the current 80 ppm refinery gate and 95 ppm downstream 

cap. The Tier 3 gasoline sulfur standards are similar to levels already being achieved in 

California, Europe, Japan, South Korea, and several other countries.

	Emission reductions from the Tier 3 program will lead to immediate air quality improvements that are critically important for states to attain and maintain the existing healthbased National Ambient Air Quality Standard (NAAQS). In the absence of additional 

controls such as the Tier 3 standards, many areas will continue to have air pollution 

levels that exceed the NAAQS in the future. 

Tier 3 will also reduce exposure to vehicle pollution for the millions of people living, working, 

and going to school near major roads.

Tier 3 is among the most highly cost-effective air quality control measures available. 

	The program is projected to cost less than a penny per gallon of gasoline, and about $72 

per vehicle. The annual cost of the overall program in 2030 is projected to be approximately $1.5 billion; however, EPA estimates that in 2030 the annual monetized health 

benefits of the Tier 3 standards will be between $6.7 and $19 billion.

	Through the use of more recent and robust cost analysis, EPA estimates that the cost of 

the total Tier 3 program (vehicle and fuel standards) will be less than half of what we 

projected in the proposal.

	By 2030, the Tier 3 standards will annually prevent:

•	Between 770 and 2,000 premature deaths

•	 2,200 hospital admissions and asthma-related emergency room visits

•	 19,000 asthma exacerbations

•	 30,000 upper and lower respiratory symptoms in children

•	 1.4 million lost school days, work days and minor-restricted activities

	 By 2030, the Tier 3 standards will also reduce numerous tons of harmful emissions. 

Table 1 illustrates the projected tons of emission reductions in 2018 and 2030.
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Table 1

Estimated Emission Reductions from the Final Tier 3 Standards

(Annual U.S. short tons)

2018 2030

Tons Percent 

of Onroad 

Inventory

Tons Percent 

of Onroad 

Inventory

NOX 264,369 10% 328,509 25%

VOC 47,504 3% 167,591 16%

CO 278,879 2% 3,458,041 24%

Direct PM2.5 130 0.1% 7,892 10%

Benzene 1,916 6% 4,762 26%

SO2 14,813 56% 12,399 56%

1,3-Butadiene 257 5% 677 29%

Formaldehyde 513 2% 1,277 10%

Acetaldehyde 600 3% 2,067 21%

Acrolein 40 3% 127 15%

Ethanol 2,704 2% 19,950 16%

The Tier 3 program is part of a comprehensive approach to reducing the impacts of motor 

vehicles on air quality and public health. 

	Tier 3 is harmonized with the California Air Resources Board (CARB) Low Emission 

Vehicle (LEV III) program so automakers could sell the same vehicles in all 50 states. 

	Tier 3 is aligned with and designed to be implemented over the same timeframe as EPA’s 

program for reducing greenhouse gas (GHG) emissions from light-duty vehicles starting 

in model year 2017. 

	Together, the Tier 3, light-duty GHG, and LEV III standards will maximize reductions 

in GHGs, criteria pollutants and air toxics from motor vehicles while streamlining 

programs and providing regulatory certainty and compliance efficiency. 

This final rule is based on extensive public input received in response to the Tier 3 proposal. 

EPA held two public hearings in Philadelphia and Chicago, and we received more than 200,000 

public comments. A broad range of stakeholders provided comments, including state and local 

governments, auto manufacturers, emissions control suppliers, refiners, fuel distributors and others 

in the petroleum industry, renewable fuels providers, environmental organizations, consumer 

groups, labor groups, private citizens, and others. EPA has also had extensive outreach with key 

stakeholders throughout the development of this rule.
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For More Information

You can access the final rule, regulations and related documents on EPA’s Office of Transportation and Air Quality (OTAQ) Web site at:

www.epa.gov/otaq/tier3.htm

For more information on this rule, please contact the U.S. Environmental Protection Agency, 

Office of Transportation and Air Quality at: 

E-mail: otaq@epa.gov