A system and method for computing emission values. In one aspect, a system and method is described to include an input module operable to receive raw activity data to define a record for an activity; a data provisioning module operable to compute standardized activity data using the raw activity data; a location module operable to compute a location hierarchy for a given location; a factor data module operable to compute factor data for a given location hierarchy and time period; a reference data module operable to compute reference data; and an emission engine operable to compute at least one emission value for the activity based on the optimal emission equation.