115 Figure : Schematic of temporal variation in emissions for an O&G site and associated measurements. Reconciliation of MMS with annual inventories is challenging due to the fragmented insights offered by measurement methods the difference in observation durations relative to the required inventory output. Aerial and onsite surveys last seconds to hours , while annual inventories provide estimates for emissions over the entire year. While CEMS typically run for extended periods, emission estimates vary in accuracy over time. Some periods have relatively high precision (solid blue areas) while others may be inaccurate due to factors such as wind direction and location (hatched areas) or estimates may be unavailable (white areas in the blue horizontal bar).