About 80% of the electric energy production in Turkey is provided by thermal power plants which use fossil fuels. Lignite, the most abundant domestic energy source, is consumed in most of these plants. Turkey has approximately 0.85% of the world's lignite reserves; however, the Turkish lignites have low calorific value and contain relatively higher amounts of ash, moisture, and sulfur. Nearly 80% of the lignite mined in Turkey is consumed in the thermal power plants since it is not appropriate for use in other types of industry and heating. In Turkey, 13 large-scale lignite-fired thermal power plants are responsible for a considerable amount of air pollution. Therefore, it is crucial to decide on the optimal place and technology for the future thermal power plants, and to equip the currently operating plants with newer technologies that will reduce amount of contaminants released into the air. In this study, the effects of the lignite-fired thermal power plants which have an important place in the energy politics in Turkey on the air pollution are investigated. We focused on SO2 pollution and the regions in which the SO2 emissions were concentrated and diffused. The pollutant diffusion areas were projected and mapped based on parameters such as wind data, isotherm curves, population density, and topographic features by using Geographical Information System (GIS) software, ArcView. The contribution of the thermal power plants to SO2 pollution was also examined. (c) 2005 Elsevier Ltd. All rights reserved.