We present the results of a dispersion-modelling study of SO2 concentrations. Overall heat-transfer coefficients (U-values) of existing wall systems in Gebze, Turkey, have been measured. Different insulation options for improvement of the thermal performance of existing wall systems have been chosen. Comparative energy-consumption analyses for each option have been performed according to ISO 9164. SO2 emissions were compiled for existing conditions and calculated for control options. Emissions, meteorological and topographical data were used in the USEPA-approved ISCLT model to predict winter-average SO2 contributions to air quality. The effects of using different exterior wall systems to these contributions were investigated.