I am a Distinguished Professor Emeritus of Hydrology and Atmospheric Sciences.  I retired in May 2021.  I also held courtesy appointments in the Department of Chemical and Environmental Engineering, and in the Division of Community, Environment and Policy, Zuckerman College of Public Health.

Born and raised in Zimbabwe, I studied chemistry in South Africa, and environmental science at Caltech.   Along the way, I worked in the platinum mining industry, and in cement and lime manufacturing.  I joined the University of Arizona in 1988.

My research in the laboratory and in the field has been focused on environmental pollutants, especially those found in the air and water that might affect people.  For example, I studied toxic metals in airborne dust, the chemistry of rain and snow, and the environmental fate of sodium azide, the propellant used in certain automobile airbags.

I have taught large introductory course in weather and climate, and smaller, more advanced courses in atmospheric physics, atmospheric chemistry, and atmospheric aerosols (suspended particulate matter).