Polychlorinated biphenyls (PCBs) have significant commercial value because of their high chemical and physical stability, resistance to fire, low vapor pressure, and high dielectric (insulating) strength. The chemical stability and physical properties of PCBs that have made them commercially valuable also makes their safe disposal difficult. The environmentally preferred option for disposing of PCB containing wastes is incineration. In order to provide assurance that the operation of the SCA incinerator did not represent a threat to public health, the Illinois EPA initiated an air sampling study in the vicinity to measure the levels of PCBs in the ambient air. Quality control checks conducted during the study revealed a previously unknown weakness in the analysis method which caused the quantitative results to be unreliable. A revised method has now been validated and will be used to further characterize ambient air quality and assess the environmental impact, if any, of the incineration of PCBs in Chicago. The document presents the overall plan for the project. Objectives: (1) Quantitatively determine PCB levels in the ambient air at three locations in the area of impacted by the SCA incinerator in southeast Chicago; (2) Correlate the air sampling results and meteorological conditions with the operational parameters from the SCA incinerator; (3) Assess the environmental impact associated with the incineration of PCBs; (4) Establish background concentrations of PCBs in the ambient air in the area.