By the late 1940's, Los Angeles had experienced several extreme smog days -- or "gas attacks" as they were called back then. Everyone had their eyes on wartime factories that had sprung up and were shooting black plumes into the air, but someone had a feeling that the cause might be something else. Arie Haagen-Smit, a Dutch professor at Caltech who would later be deemed the "father of air pollution," was technically supposed to be studying the taste and smell of pineapples when he first began to conduct research into smog. Through letters and interviews with Caltech faculty and historians, we piece together how Haagen-Smit discovered the recipe to smog, and how after he published his results, people weren't exactly ready to hear that their beloved cars were at the root of the problem.