People: Arie Haagen-Smit

“It took about 10 years for there to be concrete laboratory-proven evidence that the hydrocarbon emissions from tailpipes, when exposed to sunlight and nitrogen oxides, turned into photochemical smog.”

Arie Haagen-Smit, a biochemist who had been studying the flavor of pineapples at the California Institute of Technology, not only made that discovery, but fought hard to convince politicians, regulators and industry that cars were the biggest smog culprit in Los Angeles.