Developments in mathematical models for building air quality and ventilation analysis have changed the way we idealize buildings for purposes of analysis, the way we form system equations to effect the analysis, and the way we solve these equations to realize the analysis.  While much has been achieved more is possible.  This presentation will review the current state of the art - the building idealizations used, the system equations formed, and the solution methods applied - critically evaluate the completeness, complexity and utility of the most advanced models, and present proposals for future development.