The fourth unit to the second-semester "Comparing Political Experiences" course focuses on a specific, controversial, political issue. Using a documentary approach, this unit analyzes the concept of political change by examining the changes in Riverside, California, as that community confronts the issue of smog. The unit is divided into five student activities. The first activity introduces students to the geographic area of southern California, the causes and effects of smog, the effect of smog on Riverside, and the political environment in Riverside. Activity 2 explores the concept of mobilization and how it has affected the smog issue. Activity 3 introduces the concept of political innovation and the way it affects change. Students focus on the court case "Riverside vs. Ruckelshaus" as an illustration of political innovation. Activity 4 examines how the concept of interdependence affects change and the extent to which Riverside became interdependent with aspects of the political environment. Activity 5 teaches students how to forecast the future of a political system experiencing change by examining alternative futures for Riverside. Each activity contains the necessary student materials and student discussion questions. A data packet of supplementary readings and exercises is also included. (Author/DE)