HMMH conducted a screening modeling analysis for a proposed 7.5 MW cogeneration facility at a confidential client location. The modeling consisted of estimating impacts for the unit firing either natural gas or ULSD. The EPA SCREEN3 model was used to assess impacts for receptors below stack top elevation. For estimating impacts above stack top, Connecticut DEP’s PTPLU model was used. Maximum impacts from both models were compared to the EPA/CTDEP Significant Impact Levels (SILs) for NOx, PM10/PM2.5, SO2, and CO. The modeling was conducted in support of the New Source Review Permit application.