CMS-based inventory. We create and compare four versions of a CMS-based measurementinformed inventory for each site. The first two inventories are created using the vendorprovided quantification estimates averaged up to a 30-minute frequency. The second two are created using the rate estimates from the DLQ algorithm applied to the minute-frequency concentration observations from the two CMS solutions on the site. For each site, we compare the four CMS-based inventories to a site-level bottom-up inventory prepared according to emissions reporting guidelines set by the Pennsylvania Department of Environmental Protection 45 and the US EPA. We create the CMS-based inventories using the same methodology, regardless of the source of the emission rate estimates. We first sum all of the rate estimates across the entire time period in which there is overlapping data from the two CMS solutions being compared.