HMMH performed air dispersion modeling in support of the Massachusetts Department of Environmental Protection Environmental Results Program (MassDEP ERP) requirements for an 800 kilowatt (kW) emergency generator in a Wakefield, Massachusetts office park. Air dispersion modeling was conducted using the EPA AERMOD dispersion model. HMMH processed the meteorological data from nearby Boston Logan Airport for use in the model. A Good Engineering Practice (GEP) analysis was conducted to account for the effects of the nearby building on the generator’s plume exhaust. Modeled impacts were estimated at the building air handling intake locations and nearby sensitive receptors, and compared to the National Ambient Air Quality Standards (NAAQS). HMMH also prepared the ERP forms for submittal to MassDEP.