sentences:  from Brigham Young University (BYU) in 1978 and his Ph.D. in Economics and statistics from Iowa State University in 1981.Although his research includes many papers on topics in the fields in which he was trained—environmental economics, resource economics, and agricultural economics—he is better known for his cross-disciplinary work in environmental epidemiology and public health.He is world-renowned for his seminal work on the effects of particulate air pollution on mortality and health.