This report expands on the comparison of monitoring and modelling data and discusses possible modifications to the modelling to address some of the disagreements with available monitoring. The report concludes the approach and methods used to complete the dispersion modelling study (RWDI, 2003) and the air emissions inventory (Clearstone, Golder, 2003) were reasonable and consistent with recent applications in the region. Inconsistencies were noted in how sources were modelled. The modelling completed a reasonable job of estimating sulphur dioxide and nitrogen dioxide concentrations in Fort McKay. The modelling did not include PM2.5 emissions or an estimation of H2S concentrations in Fort McKay. The report condluded air monitoring conducted in Fort McKay gathers data for only a few of the priority compounds identified by TMAC, limiting the ability to establish background concentrations or to track progress in managing the community's exposure to those compounds.