Leak found during study: (6.5% of plumes, 1.9% 1 Counts cases where the aircraft overew, and detected, the same location twice in one day as one overight. Plumes were with 60 m of a known facility. One plume may be within that distance of multiple known facilities. A reported event was occurring at the facility during the time of overight. In cases where the aircraft detected emissions at the same facility on the same day, the average emission estimates for that location is used. Fractions are computed relative to the total number of plumes or total emissions in the lettered grouping in the table. May not sum to 100% due to category rounding.