The Joint Canada-Alberta Implementation Plan for Oil Sands Monitoring (JOSM) identified air emissions inventories as critical to obtaining accurate information on what is being emitted to the atmosphere from all activities related to oil sands developments. This report details the development and compilation of the JOSM Inventory, including identifying the data sources, compilation procedures, gap analysis, and how priority data gaps were addressed. It also provides summary information on the JOSM Inventory and accompanying database, details the associated emissions processing that was carried out to generate gridded input emissions files for modelling, and outlines the setup of the GEM-MACH modelling system.