cities in Figure , we grouped the ratios into three geographic regions: U.S. West Coast, U.S. Central, and U.S. East Coast. The U.S. Central region encompasses cities located in the Rocky Mountain, Midwest, and Gulf Coast regions. These were combined into a single U.S. Central region to address fewer TD measurements in these regions compared to the high observational density on the U.S. west and east coasts. Canadian cities were grouped into a single "Canada" category given the low number of studies reporting TD city-level estimates (n = 3). , , , , , , , , , , , , , , , , , , , , , , , , , and . The total number of ratios (i.e., individual quotients between TD and BU estimates for the cities) in Figure is 149 before averaging the ratios in studies that reported ratios for multiple cities in a region. After averaging, the total number of measurements is 42; by region: U.S. West Coast (n = 21), U.S. Central (n = 8), U.S. East Coast (n = 11), and Canada (n = 2). used column-averaged dry air CH4 mixing ratio measurements from TROPOMI in an inversion framework to estimate rates for 95 different cities across the U.S. This number of city-level TD estimates substantially outweighs the number of estimates reported across the other studies in the review. Thus, to prevent weighting the results in Figure substantially in favor of any one study or measurement method, we averaged the ratios from studies that measured emissions from multiple cities in a region with a single TD method before regional grouping with the ratios from the other studies. Furthermore, we did not include the ratios between TD and BU estimates of emissions for 19 U.S. cities and one Canadian city reported in in our analysis, as we noted the magnitude of ratios in this study were substantially higher than the other studies, irrespective of those studies using satellites or other TD methods to estimate emissions. used column-averaged dry air CH4 mixing ratios from TROPOMI, identical to the other satellite studies included in Figure , but used a 2D Gaussian technique to quantify emissions. This technique relies on using CH4 hotspots observed with TROPOMI to inform the quantification of emissions. found that urban CH4 hotspots observed with TROPOMI had better overlap with areas of population density than gridded emissions in EDGAR v6.0, the BU benchmark used in the study. Therefore, the very large discrepancies between TD and BU estimates in de Foy et al. ( ) may be partly related to issues with the allocation of CH4 emissions to urban areas in EDGAR v6.0 spatially and in quantity relative to the location of TROPOMI-observed urban CH4 hotspots.