NARSTO has initiated a new study of the technical challenges of implementing accountability under a multi-pollutant air quality management regime. In 2004, the National Research Council (NRC) published a major assessment of air quality management practices: Air Quality Management in the United States. The assessment recommended transitioning from a pollutant-by-pollutant approach to air quality management to one that would take an integrated multi-pollutant approach to controlling emissions of pollutants that posed the most significant risks. The NRC recommended that a multi-pollutant approach should stress results over process by instituting procedures for measuring the effectiveness of air quality management actions in meeting air quality management goals. Such a process is often called “accountability”. In this new activity, NARSTO will be looking at the tools, scientific knowledge, and monitoring networks that would be needed to determine whether or not air quality management actions are having the desired effects in improving human health, ecosystem health, and other air-quality related values.