The Dynamic Air Pollution Prediction System (DAPPS) involves the development and integration of the following elements: Downscaling the current numerical urban-scale weather prediction to a finer spatial and temporal resolution, and establishing a comprehensive air pollutant emission inventory that will include industrial, motor vehicle and domestic emissions, and temporal variations in these emissions. The enhanced meteorological data and the emission inventory data will be used as inputs into a photochemical dispersion model, the Comprehensive Air Quality Model with Extensions (CAMx), to produce air pollution fields for the forecast meteorology.