Air pollution in Tehran has become a major problem in recent years, due to the geographical position of the town, industries, and traffic. Most private and public vehicles are old and have no emission control systems. The Municipality of Tehran and the Department of Environment have started several actions to reduce pollution, with communication activities being part of their strategy. For better planning, and to make possible the monitoring and evaluation of the communication activities, a baseline study was completed in 2004 using direct interviews of 1,200 Tehran residents. The interviews covered aspects such as experiences, opinions, knowledge, and willingness to act. Use of and trust in several information sources and media were also investigated, in order to select the best communication mix for future activities.