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Since 2004, Tolaas technically works for the commercial research institution International Fragrances and Flavors. It provides her with access to 2,500 different scent notes — a portion of which are on these shelves — and to Head Space, a machine that breaks down any smell into its molecular components, information that's then used to piece together its synthetic counterpart. Human sweat, she notes, can have anywhere from 10 to 200 elements.