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## B.2.4.2 Emission Factors 

The MOVES emission rates, when c oupled with estimates of travel activity (vehicle -miles- traveled or VMT), provide estimates of the mass of HAP as shown in Equation B-7 ( HAP Emissions - Ground Access Vehicles ). 

Where: 

Equation B-7. HAP Emissions - Ground Access Vehicles 

## B.2.5 Stationary Combustion Sources 

I = Mass of HAP of interest (kg) 

D = HAP emission index, expressed in grams per mile (g/mi) 

N = Vehicle-miles-traveled, expressed as miles (mi) 

1/1000 = Conversion factor from grams to kilograms 

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Potential stationary combustion sources of HAPs at airports include boilers/space heaters, generators, incinerators, fire training facilities, and aircraft engine testing . The data required to prepare a HAP emission inventory for these sources include: (i) the amount of fuel consumed over a given time period, (ii) a THC emission index, (iii) a THC-to-TOG conversion factor, and (iv) a HAPs speciation profile. In nearly all cases, the types and amounts of HAP emitted by these sources depend on the type and quantity of the fuel used, operating times, and the existence of emission control equipment. 

Equation B-8 ( HAP Emissions - Stationary Combustion Sources ) provides a methodology to estimate of HAP emis sions for an individual stationary combustion source. EDMS /AEDT provides THC to TOG conversion factors for various equipment and fuel. 

Where: 

I = Mass of HAP of interest, expressed in pounds (lbs) 

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C = Total fuel consumed, expresses in gallons (for liquid fuels), million cubic feet (for natural gas), or tons (for coal) 

D = THC emission index, expressed in pounds per gallon (lbs/gal) for liquid fuels, pounds per million cubic feet (lbs/10$^{6 }$cf) for natural gas, or pounds per ton (lbs /ton) for coal 

Equation B-8. HAP Emissions - Stationary Combustion Sources 

## B.2.6 Fuel Storage Tanks 

F = THC to TOG conversion factor (unitless) 

HAP emissions from fuel storage tanks vary by fuel type and vapor pressure; containment vessel, emission control device, fuel throughput volumes, and local meteorological conditions. 

