In order to meet specific methane emissions reduction targets, we need knowledge about the spatial and temporal patters of large emitters, which dominate the majority of the anthropogenic emissions budget. We have surveyed many of these facilities in the Greater Toronto Area since 2017 using a variety of different mobile in situ laboratories. I present the methodology and summary of this work for the waste facilities in the GTA to date, as well as discuss using mobile in situ measurements to expand the scope of our measurement-based inventory to include midstream fossil gas and off-site landfill emissions from Toronto using recent in situ and total column datasets.