Cars on the road today are 99% cleaner than they were in 1970. Air quality in the United States is much, much better as a result. In Los Angeles, where I live, lead levels in the air were 50 times higher in the 1970s than today, and the amount of lead in kids’ blood has plummeted.
What made that drop possible is arguably the most important environmental technology ever invented: the catalytic converter.
California has long had the authority under the federal Clean Air Act to set emissions standards for cars and trucks that are higher than the nation’s, and its early use of that…
