An emissions inventory that leverages company-specific data and that does not rely exclusively on generic assumptions. Various regulatory and non-regulatory criteria exist. For example, OGMP 2.0 Level 4 is a MII in which company-specific measurements, engineering estimates, and/or simulations are used at the source level for material sources. Veritas Pathways 1 and 2 are MIIs that rely on site level measurements extrapolated across space and time. Most MIIs do not require exclusive use of measurements but encourage operators to minimize use of generic inputs.