Philip Stevens, Rudy Professor and former chair of the Environmental Science Faculty Group, received a B.A. in chemistry from Oberlin College, and a Ph.D. in physical chemistry from Harvard University working under the direction of Professor James G. Anderson. Prior to his career at IU, Professor Stevens was a postdoctoral research associate in atmospheric chemistry at The Pennsylvania State University, working with Professor William H. Brune on the development of instrumentation for the measurement of atmospheric free radicals.

Professor Stevens's research is focused on the characterization of the chemical mechanisms in the atmosphere that influence regional air quality and global climate change. As a leading scholar in the field of atmospheric chemistry, Stevens's research helps guide policymakers and government regulators working to improve air quality and mitigate climate change.

Since joining the faculty at IU in 1995, Stevens has secured grants from preeminent organizations including NASA, the National Science Foundation,  the Camille and Henry Dreyfus Foundation, and the Sloan Foundation. Much of his group's current research is focused on improving our understanding of the influence of biogenic emissions and their oxidation products on the chemistry of the atmosphere. This research involves laboratory studies of the kinetics of important atmospheric reactions, theoretical studies of the reaction mechanisms, and field measurements of the atmosphere in both urban and forested environments.