Smog meringues

… we spent Thursday afternoon mixing different chemical precursors, and then “baking” [meringues] under UV light to form a London peasouper, a 1950s Los Angeles photochemical smog, and a present-day air-quality event in Atlanta.

We chose these three places and times to showcase three of the classic “types” that atmospheric scientists use to characterize smogs: 1950s London was a sulfur- and particulate-heavy fog, whereas 1950s Los Angeles was a photochemical smog created by the reactions between sunlight, NOx, and partially combusted hydrocarbons. Present-day Beijing often experiences London-style atmospheric conditions, whereas Mexico City’s smog is in the Angeleno style.

Each city’s different precursor emissions and weather conditions produce a different kind of smog, with distinct chemical characteristics—and a unique flavour.

As it turns out, Arie Haagen-Smit, the man known as the “father” of air pollution science, was originally a flavour chemist who rose to prominence thanks to his work on pineapples. Nadia Berenstein, the flavour historian I interviewed for a recent episode of Gastropod, pointed me to a speech Haagen-Smit gave in the 1950s, explaining his shift in research from fruit flavours to smog science to a room full of his former colleagues. In it, he explains, “I am engaged at the present time on a super flavor problem—the flavor of Los Angeles.”