Unpredictable detections: Figure also illustrates that (a) even facilities with multiple plumes were detected on less than half of overights, and (b) many facilities with sim-ilar modeled emissions were never detected. The nature of midstream facilities make 448 both of these results unsurprising. Location of exhaust stacks from compressor drivers, or compressor vents interconnections, dier between facilities. These dierences may 450 concentrate or disperse emissions, raising or lowering the probability of that emissions will be concentrated enough to form a detectable plume. The size and shape of 452 buildings, interacting with changing wind direction and speed, likely change emissions transport and plume visibility.