Concentration measurements. The average concentration measurements from solution A (12.3 and 10.3 ppm) are much larger than the average concentration measurements from solution B (2.0 and 1.9 ppm) and solution C (2.2 and 2.0 ppm). We expect the average concentration measurement from these sensors to be close to the local background concentration for this region, which is between 1.9 and 2.1 ppm. Therefore, the concentration measurements from solution A, which uses metal oxide sensors, are likely biased high. Finally, we note that the CMS solution vendors likely account for the various characteristics of their raw concentration data when, e.g., producing localization and quantification estimates. When using the raw data directly, however, it is important to be aware of these characteristics, as they could influence inferred quantifies if not properly addressed. For example, it is necessary to remove the (likely overestimated) background from solution A's concentration data to accurately estimate emission rates using these data. Figure estimates that are the same between CMS solutions when aggregated over the entire study period, regardless of if the estimates occurred at the same time. Visually, this is the percent of the bars in Figure that have overlapping colors, including both the cross-hatched periods and the not cross-hatched periods. Alignment in distribution can be interpreted as long-term agreement between the solutions when aggregated at the month-scale. This is more pertinent for annualized applications, like inventory reporting. Alignment numbers are provided in Table , and an example calculation for both metrics is given in Section S3 in the SI.