LAUSR

When I was 15 years old, I learned that chlorofluorocarbons (CFCs) from sprays such as shaving cream to pesticides could lead to “. . .the possibility of end to life on earth” [1]. After I read that article, the world seemed smaller and humanity larger. The article, published in The New Yorker, reviewed a science-to-public-to-politics story about CFCs and their purported impact on Earth’s ozone layer. The article recounted the rapid proliferation of aerosol products during the postwar period, from 4.5 million cans in 1947 to 2.3 billion in 1968. The postwar economy of convenience fueled the rapid scale-up, and by 1970, Brodeur reported, “Practically every product that was conceivably sprayable either had been packaged or was being considered for packaging in aerosol form.” When I read that article, I was in high school in Vicenza, Italy, where my dad was serving in the military. The New Yorker was among the few English-language publications we could easily find. At 15, I knew I was younger than their targeted audience, but I devoured the nonfiction, especially the science. Brodeur’s article, in particular, gripped me. He explained how aerosol cans and the CFC gases they used as propellants were everywhere, their use doubling annually. And everyone had considered CFCs harmless because they were chemically inert. Everyone, that is, except for one Professor F. Sherwood Rowland. The ubiquity of these compounds in the environment, and even the troposphere, made Rowland, an expert in the chemistry of radioactive isotopes, wonder about their fate. Rowland would join forces with Dr. Mario Molina, then a chemist in Rowland’s lab at the University of California, Irvine. They had conducted a set of chemical calculations once, then again, and published their findings in Nature [2]. They’d discovered that chlorine atoms, when mixed with ozone, would produce runaway chemical reactions that could destroy the ozone layer of the atmosphere—the layer that shields living beings from harmful ultraviolet (UV) radiation. More surprisingly, they found that this destruction of the ozone layer would happen rapidly and additively, influenced by the propellants in the convenient aerosol cans that filled the cupboards and garages of consumers across the nation. By 1975, a year after their findings had been published, over 5 billion such cans were being produced annually—mostly by the United States and Russia—and products from pesticides to personal hygiene to food were streaming out of the cans thanks to these CFCs. Their calculations portended atmospheric disaster. Not believing that spray cans could do so much damage, Rowland and Molina turned to other experts to check their work, thinking they must have made a mathematical error. They hadn’t. Instead, impending harm to the ozone layer was confirmed by others, including Paul