Figure shows the distribution of ratios between estimates of city-level CH4 emissions derived from TD measurements and BU inventories extracted from 34 (33.0%) out of the 103 studies and grouped by region. The studies benchmarked TD estimates of CH4 emissions from individual cities against a variety of BU inventories, including the Emissions Database for Global Atmospheric Research (EDGAR; , and those developed by governments and academic researchers (e.g., , the latter of which are often highly customized. For U.S.