Richard D. Cadle, 95, a physical chemist, died of cardiorespiratory arrest on Aug. 12 in Medford, Ore.
Cadle received a B.S. in chemistry from Adelbert College (now Case Western Reserve University), in Cleveland, in 1936 and a Ph.D. from the University of Washington, Seattle, in 1940.
He then joined Procter & Gamble in Cincinnati until 1948, when he went to work as a civilian at the Naval Ordnance Test Station in China Lake, Calif. In 1950, he joined Stanford Research Institute in Palo Alto, Calif. Then in 1963, Cadle moved to the National Center for Atmospheric Research in Boulder, Colo., where he remained until retiring in 1979.
Cadle published numerous articles and five books on the theory, measurement, and occurrence of particles. He was best known for his work on atmospheric photochemistry and was a pioneer in developing an understanding of the mechanism of photochemical smog formation. He also measured volcanic emissions globally.
Cadle was an emeritus member of ACS, which he joined in 1941.
He is survived by three sons, Donald, Steven, and Gary; and three grandchildren.