Progress Timeline of Mobile Source Controls and
Management
1970s
1970: Congress passes the first major Clean Air Act
 U.S. Environmental Protection Agency (EPA) established & given broad authority to
regulate mobile sources
 90 percent reduction in emissions from new automobiles required by 1975
1971: New cars must meet evaporative emission standards for the first time; charcoal
canisters to trap gasoline vapors are developed.
1972: Exhaust gas recirculation (EGR) valves are developed as automakers strive to meet
nitrogen oxide standards.
1974: Congress delays some standards established in 1970 until 1978 and sets interim
standards at the request of the auto industry.
 Congress adopts the Energy Policy Conservation Act, setting the first fuel economy
goals.
1975: The "first generation" catalytic converters are built, significantly reducing vehicle
emissions.
 Unleaded gasoline introduced. This results in dramatic reductions in ambient lead
levels and alleviates many serious environmental and human health concerns
associated with lead pollution.
1977: Congress amends the Clean Air Act. At the request of automakers, the hydrocarbon
standard is delayed again, this time until 1980 and the carbon monoxide and nitrogen
oxides standards are relaxed and delayed until 1981.
1980s
1981: New cars meet the amended Clean Air Act standards for the first time. Sophisticated
new technology introduced to help curb emissions
o Three-way catalysts convert CO & HCs to CO2 & H20; reduces NOx to
elemental Nitrogen and Oxygen
o On-board computers & oxygen sensors optimize catalytic converter
efficiency
1983: Inspection and Maintenance (I/M) programs established in areas with air pollution
problems, requiring passenger vehicles to undergo periodic testing for malfunctioning
emission control systems.
1986: The phase-out of leaded gasoline is completed.
1989: For the first time, EPA sets fuel volatility limits aimed at reducing evaporative
emissions.
Source: http://www.epa.gov/otaq/
Revised 2/6/16
1990s
1990: EPA imposes limits on diesel fuel sulfur content to help buses and trucks meet the
1985 emission standards.
 Congress amends the Clean Air Act to require further reductions in hydrocarbons,
carbon monoxide, nitrogen oxides, and particulate emissions.
 The amendments also introduce lower tailpipe standards; more stringent emission
testing procedures; expanded I/M programs; new vehicle technologies and clean fuels
programs; and transportation management provisions.
 The 1990 amendments also give EPA, for the first time, specific authority to regulate
emissions from nonroad vehicles.
 The amendments include fuel provisions that require oxygenated gasoline (also
called reformulated gasoline), designed to reduce emissions of carbon monoxide, to
be sold in nine urban areas that do not meet air quality standards for ozone.
1992: Standards setting emission limits for carbon monoxide at cold temperatures are
established for the first time. Oxygenated gasoline is introduced in cities with high
carbon monoxide levels.
1993: The Partnership for a New Generation of Vehicles (PNGV) is established to develop
new automotive technology to help reduce air pollution by tripling the fuel economy of
typical family sedans without sacrificing safety, performance, and affordable cost.
1996: EPA issues regulations that aim to produce cleaner technology and better engine
performance in marine engines. Controlling exhaust emissions from new gasoline
spark-ignition engines will reduce hydrocarbon emissions from these engines by 75
percent by 2025.
1997: EPA finalizes emission standards for nitrogen oxides, hydrocarbons, carbon monoxide,
and particulate matter for newly manufactured and re-manufactured diesel-powered
locomotives and locomotive engines.
1998: EPA issues new emissions standards for diesel engines used in non-road
construction, agricultural, and industrial equipment, as well as in certain marine
applications.
 The first National Low Emission Vehicles (NLEVs) under the agreement were released
in New England in the 1999 model year and made available nationwide in 2001.
1999: While the number of passenger cars sold each year in the United States decreases
somewhat since 1980, the number of light trucks sold more than triples, from 2.2
million in 1980 to 8.2 million in 1999. In 1999, Sport Utility Vehicle (SUV) sales alone
(3.1 million) exceeded total light truck sales for 1980.
 EPA announces more protective tailpipe emissions standards, marking the first time
that SUVs and other light-duty trucks are subject to the same national pollution
standards as cars.
 In addition, for the first time, vehicles and fuels are considered one system. EPA
announces lower standards for sulfur in gasoline, which will ensure the effectiveness
of low emission-control technology and reduce harmful air pollution.
Source: http://www.epa.gov/otaq/
Revised 2/6/16
2000s
2000: EPA adopts final rule for non-road small spark-ignition handheld engines (e.g.,
trimmers, brush cutters, and chainsaws). The rule will reduce hydrocarbons and
nitrogen oxide emissions by 70 percent beyond the current standards.
 EPA announces plans to reduce sulfur in on-road diesel fuel by 97 percent by mid2006.
 EPA issues final rule to address emissions of hazardous pollutants (air toxics) from
mobile sources. The rule identifies 21 mobile source air toxics and sets new gasoline
toxic emission performance standards.
2001: Japanese electric-gasoline hybrid cars hit the market. The Honda Insight becomes the
first hybrid to enter the North American market.
2002: EPA joins with the Department of Energy (DOE) to provide information to consumers
about vehicle fuel economy. Consumer guides, outreach information and other
resources are provided via the internet at www.fueleconomy.gov
2003: The first new emission standards in 25 years for highway motorcycles are
established. Highway motorcycles currently produce more harmful exhaust emissions
per mile than cars or even large sport utility vehicles. When the new rule is in full
effect, it will reduce emissions of hydrocarbons (HC) and nitrogen oxides (NOx) by
about 54,000 tons a year and save approximately 12 million gallons of fuel annually by
preventing it from escaping from fuel hoses and fuel tanks.
 EPA establishes a grant program to make school buses cleaner for the 24 million
children who travel on a bus to and from school every day. The grants are under
EPA’s Clean School Bus USA initiative which is designed to limit children’s exposure
to the harmful effects of diesel exhaust from school buses.
 EMISSION STANDARDS FINALIZED FOR OCEAN-GOING VESSELS
2004: EPA Updates Vehicle Inspection and Maintenance (I/M) Program requirements to help
meet 8-hour Ozone standard
 EPA partners with automobile manufacturers such as Daimler-Chrysler, and Ford to
design and market zero-emission engines.
 EPA certifies first hybrid SUV, the Ford Escape.
 EPA presents program to develop hybrid hydraulic engines for use in heavy-duty nondiesel engines.
Source: http://www.epa.gov/otaq/
Revised 2/6/16