The Challenge of Air Pollution in the Mid-1900s
Following World War II, the United States experienced significant economic and population growth, coupled with rapid suburbanization. This led to increased reliance on personal vehicles and a decline in public transit systems. As a result, the number of cars and trucks on the road surged, along with the construction of new highways. This rapid increase in motor vehicles brought about a significant increase in air pollution, particularly in urban areas, with detrimental effects on both public health and the environment.
The Historic Success of the Clean Air Act
The landmark Clean Air Act, passed by Congress in 1970, gave the newly established Environmental Protection Agency (EPA) the authority to regulate pollution from vehicles and other transportation sources. The EPA, in collaboration with the State of California, has spearheaded the national effort to reduce vehicle pollution by implementing increasingly stringent standards. The success of U.S. vehicle pollution control under the Clean Air Act is evident in several key areas:
- New passenger vehicles are now approximately 98-99% cleaner for most tailpipe pollutants when compared to those of the 1960s.
- Fuels have been significantly cleaned up, with lead eliminated entirely and sulfur levels reduced by over 90% compared to pre-regulation levels.
- U.S. cities have experienced substantial improvements in air quality, despite continued population growth and an increase in vehicle miles traveled.
- Emission standards have spurred technological innovation within the automotive industry.
Pollution from vehicles, engines, and fuels has been dramatically reduced while maintaining economic growth.
These policies have led to a healthier environment and improved public health for Americans. Since 1970, the EPA has actively set and enforced emission standards for a wide range of sources, from passenger vehicles and heavy-duty trucks and buses to farm and construction equipment, as well as marine and locomotive engines and even lawn and garden equipment. The advances in air quality have been achieved despite increased economic activity per person.
Cleaner Cars, Trucks, and Fuels
Compared to 1970 vehicle models, new cars, SUVs, and pickup trucks are now approximately 99% cleaner for common pollutants, including hydrocarbons, carbon monoxide, nitrogen oxides, and particle emissions. Additionally, new heavy-duty trucks and buses are also about 99% cleaner than their 1970 counterparts.
Lead Removal from Gasoline
Initially, motor vehicles were a major contributor to lead emissions. The EPA began phasing out lead in gasoline in the 1970s, and it was fully prohibited after 1995. As a result, levels of lead in the air decreased by 94% between 1980 and 1999.
Spurring Innovation in Cleaner Cars, Trucks, and Fuels
EPA’s vehicle emissions standards have been instrumental in driving the development and implementation of various groundbreaking technologies. The automotive catalytic converter, in particular, is regarded as one of the most significant environmental inventions of all time. Emissions standards have led to the adoption of numerous modern automotive technologies—such as computers, fuel injection, and on-board diagnostics—resulting in cars that are not only significantly cleaner but also of higher quality, more reliable, and more durable. The vehicle emissions control industry employs approximately 65,000 Americans with domestic annual sales of $26 billion.
Contributions to the U.S. Economy
Efforts to reduce air pollution from transportation have proven to be cost-effective. For every one dollar spent on these programs, the American people receive nine dollars in benefits related to public health and the environment. This is based on an analysis of major federal rules from 2000 to 2012.
Timeline of Major Accomplishments
In the early 1950s, a researcher in California first linked air pollution to cars. The researcher determined that pollutants from traffic were to blame for the smog over Los Angeles. At the time, new cars emitted nearly 13 grams per mile of hydrocarbons (HC), 3.6 grams per mile of nitrogen oxides (NOx), and 87 grams per mile of carbon monoxide (CO). Since then, the EPA set standards to bring down the levels of these pollutants, and the auto industry responded by developing new emission control technologies.
The Road Ahead
Despite significant progress, numerous areas in the United States still experience poor local air quality, and more work is needed. The EPA is now addressing the critical challenge of climate change. Carbon pollution from burning fossil fuels is rapidly changing the earth’s climate, and the transportation sector is a major source of carbon pollution in the U.S. The EPA has set carbon emissions standards for passenger cars, trucks, and on-road heavy-duty trucks and buses, and it’s currently developing standards for aircraft.
