The Global Modeling Initiative (GMI) Chemical Transport Model (CTM) is part of the NASA Modeling Analysis and Prediction (MAP) program. The GMI CTM is used to assess the impacts of atmospheric circulation and composition change due to anthropogenic emissions, such as those from aircraft, biomass burning, fossil fuel combustion, and use of ozone depleting substances (ODS). GMI studies investigate changes in stratospheric ozone and the roles of long-range transport and changing emissions on air quality.