Historically, BU models have gone through a persistent oversimplification, often lacking pertinent details 455 regarding gas compositions, failure events and variability in emissions within and between days, by averaging emissions with emission factors. Averaging emissions over many facilities overlooks facility-to-facility variation, which can be accounted for by mechanistically modeling emissions that vary with flow rates. MAES addresses these shortcomings by providing a correlation between major equipment' operational states and fluid flows to their emissions, a fine resolution to estimate emissions down to 1-second, and by enabling the 460 correct integration of field measurements into a measurement-informed inventory to account for abnormal events.