CEI performed air dispersion modeling for a 1 MW diesel generator to be installed at an existing medical center in Brockton, Massachusetts. The generator was proposed to be installed at ground level adjacent to the building and discharge through a single stack running up the side of the building. Oris Solution’s AerScreen for Windows and BEEST were used to construct a model of the multi-tier buildings, terrain, and receptor grids in proximity of the stack and to evaluate emissions in comparison to the Significant Impact Levels (SILs) and National Ambient Air Quality Standard (NAAQS). All emissions were below the applicable NAAQS for all pollutants. CEI prepared an Air Quality analysis Report summarizing the modeling procedures and results for submission to MassDEP.