After the end of the Second World War, Americans began to migrate from the city to the suburbs on a large scale. These new suburban residents need cars for daily commuting, and the country quickly begins driving at an unprecedented speed. As the number of cars on the road increases, fuel consumption increases - and air pollution unexpectedly increases.
California became the first state to establish clean air standards, in part because of the region's heat and natural terrain capturing smoke in crowded cities such as Los Angeles. By the 1940s, residents had begun to suffer from watery eyes and breathing problems due to increased pollution.
In the 1960s - in opposition from automakers, California began demanding that various emission control devices be placed in cars. This led to the emergence of catalytic converters and the demise of lead-based gasoline. In 1970, President Richard Nixon signed the Clean Air Act. The Act gives the Federal Environmental Protection Agency (EPA) the power to protect and improve the state's air quality. The Clean Air Act results in a decrease in carbon monoxide, hydrocarbon and nitrogen oxide emissions. Since then, the bill has undergone some modifications - several major revisions were made in 1990, and minor modifications were made in the following years.
The 1990 Act proposed a “level” of two countries detailing how automakers must reduce emissions. The Tier 1 standard came into effect in the mid-1990s and is currently phased out of the more stringent Tier 2 standard. According to Tier 2 rules, SUVs, pickups, trucks and large passenger cars meet the same national emission standards as cars. It also requires the use of low-sulfur gasoline to make the car run cleaner, and said the diesel engine must comply with the same emission standards as gasoline engines.
California's emissions standards are stricter than the federal ones. States can choose to follow the California standards if they choose, and several do. Cars are classified according to a number of acronyms:
Low Emission Vehicle (LEV): releases fewer emissions than the average new car
Ultra Low Emission Vehicle (ULEV): releases 50 percent fewer emissions than the average new car
Super-Ultra Low Emission Vehicle (SULEV): releases 90 percent fewer emissions than the average new car
Zero Emission Vehicle (ZEV): releases no emissions at all; includes electric cars and fuel-cell cars
On the next page, we'll examine how automakers comply with federal and state emissions regulations to help promote fuel efficiency and green driving. We'll also learn how eco-friendly driving technologies can help us reduce our carbon footprint.