During his time at NCAR he served as president of the International Commission on Atmospheric Chemistry and Radioactivity within the International Association of Meteorology and Atmospheric Sciences. He was also a  of the American Association for the Advancement of Science and a member of numerous other scientific societies.
He served as an expert witness during hearings before the U.S. Congress and United Nations on radioactive fallout. He also spearheaded the cleanup of plutonium contamination in the soil surrounding the Rocky Flats nuclear weapons manufacturing facility located outside of Boulder, after measuring levels of radioactivity surrounding the site. He also supported the Southern Poverty Law Center which represented the victims of government-sponsored radiation testing on low-income black citizens.