Most people in the United States spend far more time indoors than outdoors. Yet, many air pollution regulations and risk assessments focus on outdoor air. These often overlook contact with harmful contaminants that may be at their most dangerous concentrations indoors. A new book from the National Research Council explores the need for strategies to address indoor and outdoor exposures and examines the methods and tools available for finding out where and when significant exposures occur. The volume includes: a conceptual framework and common terminology that investigators from different disciplines can use to make more accurate assessments of human exposure to airborne contaminants; an update of important developments in assessing exposure to airborne contaminants: ambient air sampling and physical chemical measurements, biological markers, questionnaires, time-activity diaries, and modelling; and a series of examples of how exposure assessments have been applied - properly and improperly - to public health issues and how the committee’s suggested framework can be brought into practice. This volume will provide important insights to improve risk assessment, risk management, pollution control, and regulatory programs.