The full reactive atmospheric oxidation profile of peroxyacetic acid under high NO conditions was examined using electronic structure calculations at various levels of theory. The three pathways resulting from the reaction of peroxyacetic acid with the hydroxyl radical were (1) addition of OH to the central carbon, (2) abstraction of the acidic hydrogen, and (3) abstraction of the methyl hydrogen. These pathways were followed to terminal product steps, the major products being acetic acid for pathway 1 and formaldehyde for pathways 2 and 3.