Colorado State University

Dr. Ravishankara is a Professor in the Departments of Chemistry and Atmospheric Science at Colorado State University.  He was at National Oceanic and Atmospheric Administration’s Chemical Sciences Division (CSD) of Earth System Research Laboratory for nearly 30 years in Boulder, CO. There, he served as the Director of CSD from 2006 through 2014, and was a Senior Scientist prior to the Directorship.  Before coming to NOAA, he was at Georgia Institute of Technology in Atlanta. Dr. Ravishankara has worked over the past three and a half decades on the chemistry of the Earth's atmosphere as it relates to stratospheric ozone depletion, climate change, and regional air quality.  His measurements in the laboratory and in the atmosphere have contributed to deciphering the ozone layer depletion, including the ozone hole; to quantifying the role of chemically active species on climate; and to advancing understanding of the formation, removal, and properties of pollutants. He is an author or coauthor of nearly 350 peer-reviewed publications. Dr. Ravishankara is a member of the US National Academy of Sciences, as well as Fellow of the American Geophysical Union, of the Royal Society of Chemistry, of the American Association for the Advancement of Science, and of the International Union of Pure and Applied Chemistry.  His many awards include the Polanyi Medal of the Royal Society of Chemistry, the Stratospheric Ozone Protection award of the US Environmental Protection Agency, and the American Chemical Society's award for Creative Advances in Environmental Sciences.  He is currently a co-chair of the WMO/UNEP Science Assessment Panel on Stratospheric Ozone and a member of the Science Advisory Panel of the Climate Clean Air Coalition of UNEP.  He has served or continues to serve on many national and international committees. He is on the Editorial Board of Physical Chemistry Chemical Physics.  He has previously served as an Editor of Geophysical Research Letters, and has been on the Editorial Board of Chemical Physics Research Letters and International Journal of Chemical Kinetics.

Selected Publications:

1. Ravishankara AR, Daniel JS, and Portmann RW (2009) Nitrous Oxide (N2O): The Dominant Ozone-Depleting Substance Emitted in the 21st Century. Science 326(5949):123-125.
2. Smith I.W.M. and Ravishankara A (2002) Role of hydrogen-bonded intermediates in the bimolecular reactions of the hydroxyl radical. J. Phys. Chem. A 106(19):4798-4807.
3. Brown S, Stark H, Ciciora S, and Ravishankara A (2001) In-situ measurement of atmospheric NO₃ and N₂O₅ via cavity ring-down spectroscopy. Geophys. Res. Lett., 28(17):3227-3230.
4. Brown S, Burkholder J, Talukdar R, and Ravishankara A (2001) Reaction of hydroxyl radical with nitric acid: Insights into its mechanism. J. Phys. Chem. A 105(9):1605-1614.
5. Brown S, Ravishankara A, and Stark H (2000) Simultaneous kinetics and ring-down: Rate coefficients from single cavity loss temporal profiles. J. Phys. Chem. A 104(30):7044-7052
6. Talukdar R, Longfellow C, Gilles M, and Ravishankara A (1998) Quantum yields of O(¹D) in the photolysis of ozone between 289 and 329 nm as a function of temperature. Geophys. Res. Lett. 25(2):143-146.
7. Gierczak T, Burkholder J, Bauerle S, and Ravishankara A (1998) Photochemistry of acetone under tropospheric conditions. Chem. Phys. 231(2-3):229-244.
8. McKeen, S.A., T. Gierczak, J. B. Burkholder, P. O. Wennberg, T. F. Hanisco, E. R. Keim, R.-S. Gao, S. C. Liu, A. R. Ravishankara, D. W. Fahey, (1997) The photochemistry of acetone in the upper troposphere: A source of odd-hydrogen radicals. Geophys. Res. Lett. 24(24):3177-3180.
9. Ravishankara A (1997) Heterogeneous and multiphase chemistry in the troposphere. Science 276(5315):1058-1065.
10. Solomon S, Garcia R, and Ravishankara A (1994) On the role of iodine in ozone depletion. J. Geophys. Res.-Atmospheres 99(D10):20491-20499. 11. Ravishankara A, et al. (1994) Do hydrofluorocarbons destroy stratospheric ozone. Science 263(5143):71-75. 12. Hanson D, Ravishankara A, and Solomon S (1994) Heterogeneous reactions in sulfuric-acid aerosols - a framework for model-calculations. J. Geophys. Res.-Atmospheres 99(D2):3615-3629. 13. Hanson D and Ravishankara A (1994) Reactive uptake of ClONO₂ onto sulfuric-acid due to reaction with HCl and H₂O. J. Phys. Chem. 98(22):5728-5735. 14. Ravishankara A, Solomon S, Turnipseed A, and Warren R (1993) Atmospheric lifetimes of long-lived halogenated species., Science 259(5092):194-199. 15. Hanson D and Ravishankara A (1992) Investigation of the reactive and nonreactive processes involving ClONO₂ and HCl on water and nitric-acid doped ice. J. Phys. Chem. 96(6):2682-2691. 16. Vaghjiani G and Ravishankara A (1991) New measurement of the rate coefficient for the reaction of OH with methane. Nature, 350(6317):406-409. 17. R. Talukdar, A. Mellouki, T. Gierczak, J. B. Burkholder, S. A. McKeen, and A. R. Ravishankara, (1991) Atmospheric lifetime of CHF₂Br, a proposed substitute for halons,  Science 252(5006):693-695. 18. Hanson D and Ravishankara A (1991) The reaction probabilities of ClONO₂ and N₂O₅ on 40-percent to 75-percent sulfuric-acid-solutions. J. Geophys. Res.-Atmospheres 96(D9):17307-17314. 19. Wine, P. H., A. R. Ravishankara, N. M. Kreutter, R. C. Shah, et al. (1981) Rate of reaction of OH with HNO₃. J. Geophys. Res.-Atmospheres 86:1105-1112. 20. Ravishankara A, Nicovich J, Thompson R, and Tully F (1981) Kinetic-study of the reaction of OH with H₂ and D₂ from 250-K TO 1050-K. J. Phys. Chem. 85(17):2498-2503.