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Equation C-10 shows the calculation of the motor vehicle CO 2e emissions as a functi on of vehicle miles traveled. This calculation can be made for each vehicle type or for a composite vehicle fleet mix. 

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If vehicle fuel usage is known (via airport records), then the CO$_{2e }$emissions should be calculated as a function of the fuel-based emission factors (shown in Table C-3 , GHG Emission Factors for GSE ). These emission factors should then be applied to determine the CO $_{2}$, CH$_{4}$, and N $_{2}$O emissions (in metric tons), as shown for an example diesel bus in Equation C-11 , ( CO$_{2e }$ Emission Calculation of Diesel Bus ). 

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## C.2.5 Stationary Sources 

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The following section discusses the methodologies for computing GHG emissions from stationary sources. Stationary sources at an airport which emit GHG emissions include boilers, generators, snowmelters, and fire training facilities. Storage of fuel (i.e., jet fuel, avgas, gasoline, and diesel) is a potential source of evaporative hydrocarbon emissions, but does not produce the types of hydrocarbons that contribute directly to climate change. 

Typically, stationary source fuel usage can be obtained from fuel purchase records, storage tank throughput, or other records. If fuel usage records are not available, the fuel usage should be estimated based on the hours of operation and hourly fuel flow rates for each source from manufacturer data. 

