{"term":{"id":"01541","title":"decay rate","longtitle":"IUPAC Gold Book - decay rate","doi":"10.1351\/goldbook.D01541","code":"D01541","status":"current","definitions":[{"id":1,"text":"The rate at which a pollutant is removed from the atmosphere either by reaction with reactive transient species such as the $\\ce{HO}$ radical, $\\ce{O3}$, etc., by photodecomposition initiated by light absorption by the impurity, or by loss at the surface of aerosols, the earth, etc. The decay rate as applied to radioactive materials is related to the radioactive half-life (\\(t_{1\/2}\\)) of the particular isotopic species A and its concentration \\([A]_{t}\\), at the given time (\\(t\\)): \\[\\rm{Rate}=\\frac{[A]_{t}\\ \\ln 2}{t_{1\/2}}\\]","contexts":[],"links":[{"term":"radioactive","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/R05077"}],"sources":["PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2183 (https:\/\/doi.org\/10.1351\/pac199062112167)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/D01541\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/D01541\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/D01541\/plain"},"citation":"Citation: 'decay rate' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351\/goldbook.D01541","license":"The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0\/) for individual terms.","collection":"If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .","disclaimer":"The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.","accessed":"2026-06-20T23:06:56+00:00"}}