A simple air quality model prototype for EPA's third-generation modeling system, the Models-3 system, was recently implemented to test several design concepts. The prototype uses a time-splitting approach and process modules can be exchanged easily, without any restructuring of the model data flow. The prototype facilitates performance evaluations under realistic atmospheric conditions. Here, advection tests with idealized flow fields are used for preliminary evaluations of different advection schemes. Then, the CAPTEX tracer experiment is utilized to test the schemes with prognostic wind fields, in the presence of vertical diffusion, and trajectory errors are estimated. The objective is to create a robust test-bed environment for determining the most desirable characteristics of advection schemes in air quality modeling.