programs, including CERCLA, FIFRA, and TSCA. Before joining Gradient, Dr. Rhomberg was on the faculty of the Harvard School of Public Health and was employed by the Environmental Protection Agency. Dr. Rhomberg has been involved in policy development with a focus on current issues in the interpretation of toxicological data in human health risk assessment. He was recognized as Outstanding Practitioner of the Year by the Society for Risk Analysis in 2009. Dr. Rhomberg has a B.Sc. (with honors) in biology from Queen’s University in Ontario, Canada, and a Ph.D. in population biology from the State University of New York at Stony Brook.
Albert A. Viggiano, a research chemist with the Space Vehicles Directorate of the Air Force Research Laboratory, graduated from the University of California at Berkeley with a B.Sc. in chemistry (with highest honors) in 1976. He received his Ph.D. in chemical physics from the University of Colorado at Boulder in 1980. Since graduate school, he has been active in the fields of atmospheric ion chemistry and kinetics, specifically in measuring ion molecule reaction rates of interest to atmospheric chemistry. Dr. Viggiano developed a chemical ionization mass spectrometer detection scheme for studying the thermal decomposition of N2O5 and was involved in the chemistry research that allowed sulfuric acid measurements in the atmosphere to be made. As a postdoctoral fellow in Heidelberg, Germany, he used these measurements to derive the first height profiles of sulfuric acid in the atmosphere and was involved in obtaining and analyzing in situ mass spectrometric data on the ion composition of the stratosphere. Since coming to the Air Force Research Laboratory in 1983 he has worked on measurements of ion kinetics related to a number of problems over a broad range of conditions. Dr. Viggiano has developed a technique that allows the effects of internal energy on the reactivity of gas- phase ion-molecule reactions to be studied. Using this technique, he has studied the effect of rotational energy on reactivity in more systems than have been studied anywhere. He has been instrumental in developing a technique to measure ion-molecule reactions at temperatures over 1000 K for the first time. The addition of a supersonic expansion source to the SIFDT allows for the measurement of mass selected cluster ions at thermal energy for the first time. A high-pressure turbulent flow tube is the first of its type for studying ion-molecule reactions. Most recently, he has developed a technique that allows for measuring the kinetics of numerous unique plasma reactions, including a heretofore previously undiscovered process, electron-catalyzed mutual neutralization. Dr. Viggiano has authored or coauthored over 320 papers and book chapters and has given 80 seminars at universities and laboratories and over 300 presentations at scientific meetings. He was lead author of the paper of the year at the Phillips Laboratory in 1993 and spent 2 months at the Max Planck Institut für Kernphysik working with Frank Arnold under the Air Force Window on Europe program. He won the Loeser award in 1997 and has won the Air Force Basic Research Award and the Air Force Science and Technology Achievement Award.