Docket No. EO-05-01. Docket No. EO-05-01. This report describes dispersion modeling performed for Units 1 and 4 at Mirant's Potomac River Generating Station. The purpose of the modeling was to demonstrate that Units 1 and 4, operating together under specific loads and during certain periods in a calendar day will not cause or contribut to excceedences of the National Ambient Air Quality Standards (NAAQS).