Comparison of the study estimate to other emission estimates. All estimates utilize emission factors from the referenced study and activity estimates developed in this study for the study area. The leftmost bar summarizes all emissions simulated in the study, while remaining bars compare emissions estimates for only pipeline leaks. Estimates using emission factors from both the greenhouse gas inventory (GHGI) and greenhouse gas reporting program (GHGRP) are statistically similar to results from this study. In contrast, estimates based upon emission factors from a prior study of distribution mains (Lamb et al., 2015) are not statistically similar. DOI: https://doi.org/10.1525/elementa.258.f4