For fundamental investigations of the structure and dynamics of materials using X-ray diffraction, including pioneering nanosecond resolution X-ray studies and the development of three-dimensional X-ray structural microscopy with submicron resolution.
For pioneering research in disturbance and landscape ecology and in modeling of land-use change with its implications for global changes, which have influenced environmental decision making on a worldwide scale.
For distinguished research on the air/surface exchange of atmospheric trace gases and particles and their interactions with the Earth's biogeochemical cycles, and for pioneering developments in atmospheric sampling methodologies with special emphasis on the global mercury cycle.
For original studies of the genetic effects of radiation in mammals. A world authority on mammalian mutagenesis, he and co-workers provided the experimental basis for estimating the genetic hazards of radiation to man and for the corresponding recommendations of national and international standards bodies