Part II of this document presents the most important full length original papers prepared during the 'Practical Demonstration of Urban Air Quality Simulation Models.' It includes the 'Common Data Base for the Test-City' which was used for the model calculations, brief descriptions of the different models used in the 'Practical Demonstration,' and the results of the model calculations for the 'Test City.' This document surveys a variety of well-known Gaussian plume models in widespread use and notes the differences between them. It also suggests explanations for the possible band width in model results that may be caused by such differences.