Elemental compositions of the coal, various ash fractions and suspended particles in the stack of the Chalk Point (coal fired) power plant in southern Prince George's County, Maryland have been measured by instrumental nuclear activation methods. Similar analyses were performed on ambient particulate samples collected at ground level by a network of stations near the plant and with a mobile sampling vehicle equipped with an SO/sub 2/ analyzer and condensation nuclei counter to detect the plume. This particular plant appears to cause less enrichment of moderately volatile elements on suspended particles in the stack (with respect to the input coal) than plants studied by other US groups. The enrichment factors (with respect to the earth's crust) of most elements on the emitted particles are rather similar to values observed for background ambient particles in the area. Thus, emissions from the plant raise the ambient concentrations of most elements on particles rather uniformly without greatly altering the pattern of relative concentrations. 7 references, 2 figures, 1 table.