1970sReputable sourceWell documented
Cleaning Up the Car: Emissions and the Clean Air Act
On the timeline · around 1970s ·
What happened
As smog choked cities, the U.S. Clean Air Act of 1970 set strict limits on the pollutants cars could emit. To meet them, automakers phased out leaded gasoline and, from the mid-1970s, fitted vehicles with catalytic converters that chemically neutralize harmful exhaust gases. Emissions of pollutants like carbon monoxide, lead, and smog-forming compounds from new cars fell dramatically over the following decades.
Why it matters
Environmental regulation reshaped the automobile as profoundly as any engineering advance, cleaning the air of a century's worth of tailpipe pollution and setting the industry on the long road toward the cleaner and electric cars of today.