Regulations

Gasoline (Light Duty Vehicle) Regulations

In 1970, the U.S. Congress passed the Clean Air Act, which required a 90% reduction in emissions from new automobiles by 1975, and resulted in the introduction of the first generation catalytic converter. In 1985, the Environmental Protection Agency (EPA) mandated stringent emission standards for diesel-fueled trucks and busses to begin in 1991 and 1994. Since that time, emissions regulations have continued to progress toward increasingly stringent control measures in geographic regions that still fail to attain the National Ambient Air Quality Standards. These regions are known as non-attainment areas. Additionally, the California Air Resources Board (CARB) has put in place even tougher emission standards, and is often seen as a leader by other U.S. states when adopting their own emissions control regulations. Many European countries have been even more aggressive in implementing emissions controls. Although control measures have reduced pollutant emissions per vehicle over the past 20 years, the number of cars and trucks on the road and the miles they are driven have doubled to approximately two trillion miles per year in the United States.

As emissions standards have progressed, light duty vehicle manufacturers have moved to increasingly more advanced emission control technologies. Industry standards call for three-way catalytic converters that allow for simultaneous conversion of the three criteria pollutants: hydrocarbons (HC), carbon monoxide (CO) and oxides of nitrogen (NOx). In late 1998, to address light duty vehicle emissions, CARB adopted the Low Emission Vehicle II, or LEV II, program, which was followed by the EPA’s Tier 2 program. Europe implemented similar regulations under Euro III (effective 2000), Euro IV (effective 2005), and Euro V (effective 2009).