![[logo] US EPA](https://webarchive.library.unt.edu/eot2008/20081006180043im_/http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
Milestones
View important dates in the history of mobile source air pollution control and regulation.View important dates in the history of mobile source air pollution control and regulation.
1970s
1970: Congress passes the first major Clean Air Act, requiring a 90 percent reduction in emissions from new automobiles by 1975. Congress also establishes the U.S. Environmental Protection Agency (EPA), giving it broad responsibility for regulating motor vehicle pollution. New cars must meet a 0.41 gram of hydrocarbons per mile standard and a 3.4 grams of carbon monoxide per mile standard by 1975; nitrogen oxide emissions must be reduced to 0.4 grams per mile by 1976 (the nitrogen oxide standard was later revised—see 1977). The law also directs EPA to set health-based "National Ambient Air Quality Standards" for six pollutants.
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 the hydrocarbon and carbon monoxide standards 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. The Corporate Average Fuel Economy (CAFÉ) program establishes a phase-in of more stringent fuel economy standards beginning with 1975 model vehicles.
1975: The "first generation" catalytic converters are built, significantly reducing vehicle emissions. The use of converters provides a huge indirect benefit as well: because lead inactivates the catalyst, unleaded gasoline is introduced in 1975. 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 delayed until 1981. The nitrogen oxides standard is also relaxed to 1 gram per mile.
1980s
1981: New cars meet the amended Clean Air Act standards for the first time. Sophisticated three-way catalysts with on-board computers and oxygen sensors appear in most new cars, helping to optimize the efficiency of the catalytic converter.
1982: EPA again lowers the limit on the amount of lead allowed in gasoline.
1983: Inspection and Maintenance (I/M) programs are established in areas with air pollution problems, requiring passenger vehicles to undergo periodic testing for malfunctioning emission control systems.
1985: EPA adopts stringent emission standards for diesel-powered trucks and buses, to take effect in 1991 and 1994.
1986: The phase-out of leaded gasoline is completed.
1989: For the first time, EPA sets fuel volatility limits aimed at reducing evaporative emissions.
1990s
1990: EPA imposes limits on diesel fuel sulfur content to help buses and trucks meet the 1985 emission standards (which become effective in the early 1990s).
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, designed to reduce emissions of carbon monoxide, to be sold in areas that do not meet air quality standards for the pollutant. Reformulated gasoline, designed to reduce emissions of volatile organic compounds and toxic air pollutants, must be sold in the nine worst areas that do not meet the minimum national air quality standards for ozone.
1991: EPA establishes lower tailpipe standards for hydrocarbons and nitrogen oxides as required by the 1990 Clean Air Act. These standards take effect beginning with 1994 models.
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.
1992-1993: A wintertime oxygenated fuel program begins.
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.
Limits on sulfur content of diesel fuel take effect.
1994: Phase-in begins for cleaner vehicle standards and technologies required by the 1990 Clean Air Act.
1995: The Reformulated Gasoline program, authorized by the Clean Air Act Amendments, begins targeting 10 metropolitan areas with severe smog problems. To meet federal emissions standards in these areas, this program requires gasoline refiners to reformulate gasoline by blending fuels with oxygenates and reducing gasoline components that contribute to air toxic emissions and ozone formation.
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, particulate matter, and smoke for newly manufactured and re-manufactured diesel-powered locomotives and locomotive engines.
1998: EPA issues new emissions standards for diesel engines used in nonroad construction, agricultural, and industrial equipment, as well as in certain marine applications. The standards are a major step forward in reducing ozone and particulate matter emissions nationwide. Very few of these engines had ever faced any kind of emission standard requirement before the mid-1990s.
The Clinton Administration, the automotive industry, and the Northeastern states reach an agreement to put cleaner cars on the road before they could be mandated under the Clean Air Act. The new cars are called National Low Emission Vehicles (NLEV). The first 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. As a result, the total fuel usage and emissions attributable to these vehicles increases.
EPA issues a final rule to reduce nitrogen oxides and particulate matter emissions from new large marine diesel engines. These engines are used in a variety of capacities, including fishing boats, tug and tow boats, dredgers, coastal and Great Lakes cargo vessels, and ocean-going vessels.
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. Standards are set at an average of 0.07 grams per mile for nitrogen oxides for passenger vehicles by 2004. 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.
Standards for hydrocarbons, nitrogen oxides, carbon monoxide, and particulate matter are phased in between 1999 and 2008.
2000+
2000: EPA adopts final rule for nonroad 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 develops a comprehensive national control program that will regulate the heavy-duty vehicle and its fuel as a single system. These new standards will apply to model year 2007 heavy-duty on-road engines and vehicles.
EPA announces plans to reduce sulfur in on-road diesel fuel by 97 percent by mid-2006. 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. Almost every major automaker is putting finishing touches on a high-efficiency vehicle.