The significance of the impact of transportation system characteristics on the urban quality has resulted in a need to evaluate certain transportation air quality-oriented policy statements regarding the effect of present efforts to reduce emissions from automobile operation or to design transportation systems that do not constitute a danger to air quality. The evaluation of these policies requires the integration of planning techniques from both transportation and environmental fields.The classical transportation system planning process involves a well-established sequence of data acquisition and systems analysis activities. Likewise, the regional air pollution planning procedures also depend on the use of a sequence of empirical models that require a substantial data base. An interface of the transportation system and air pollution control planning processes is clearly required; the output of one or more of the members of the sequence of transportation models must be translated into an emission inventory that is required to drive the sequence of air pollution models.This paper describes such an integration developed as part of the Argonne Transportation-Air Pollution Model. Two policy applications using this model are described to illustrate the sequence of steps required to use transportation data in an air quality model and to indicate how a transportation air quality model can be used as a policy evaluation tool. These two policy evaluations are (1) the reduction of automotive emission of hydrocarbons, carbon monoxide, and nitrogen oxides in the Chicago metropolitan area that would be achieved by the current federal automotive emission standards, and (2) the reduction of these pollutants that would be achieved by applying both the federal standards and a proposed City of Chicago ordinance which initiates an automotive inspection-maintenance system.