--- cited_by: [] definition: 'Peroxyacyl nitrates (PANs) are secondary pollutants in photochemical smog. Free radical reactions catalyzed by ultraviolet light from the sun oxidize unburned hydrocarbons to aldehydes, ketones, and dicarbonyl compounds, whose secondary reactions create peroxyacyl radicals, which combine with nitrogen dioxide to form peroxyacyl nitrates. (Source: Chegg http://www.chegg.com/homework-help/questions-and-answers/11-peroxyacyl-nitrates-pans-secondary-pollutants-photochemical-smog-free-radical-reactions-q3980691)' href: https://data.globalchange.gov/gcmd_keyword/d44d3115-91d1-4655-9e6e-babfe39e1632.yaml identifier: d44d3115-91d1-4655-9e6e-babfe39e1632 label: Peroxyacyl Nitrate parent_identifier: 9e5ec924-2fd3-4cbb-a7eb-ffde114d0cb9 uri: /gcmd_keyword/d44d3115-91d1-4655-9e6e-babfe39e1632