Lorenz curve for the different North American production regions where ground-based downwind measurements of oil and gas production sites have been reported (Rella et al., 2015; Zavala-Araiza, Lyon, et al., 2015; Robertson et al., 2017). Percent of emissions is shown as a function of percent of sites. In all cases, the emissions distributions are characterized by a disproportionate influence of high-emitting sites. The Red Deer region characterized in this work (red line) is more skewed than the Denver-Julesburg, Uintah (Uintah line on top of Denver-Julesburg line), and Upper Green river production regions. DOI: https://doi.org/10.1525/elementa.284.f8