content_image/534267.jpg
Equation B-6 ( HAP Emissions – GSE ) can be used to calculate the HAP emissions from an individual piece (or type) of equipment. T he THC to TOG conversion factor s (as used in EDMS/AEDT) for diesel, gasoline, CNG, and LPG equipment are 1.07, 1.043, 1.002, 1.0995, respectively. 

Where: 

## B.2.4 Ground Access Vehicles 

I = Mass of THC of interest, expressed in kilograms (kg) 

L = Average rated brake horsepower 

M = Load factor, expressed as a percentage 

B = Time in operation, expressed as minutes 

D = THC emissions index, expressed in grams per horsepower-hour (g/hp-hr) 

F = THC to TOG conversion factor (unitless) 

H= Speciation profile for HAP of interest (mass fraction) 

1/60 = Conversion factor from minutes to hours 

1/1000 = Conversion factor from grams to kilograms 

<img src='content_image/534267.jpg'>

On-site ground access vehicles are the various fleets of public and privately -owned motor vehicles traveling on airport roadways, and in parking lots and parking garages by passengers, employees, commercial vehicles and cargo carriers. These fleets typically include cars, vans, taxis, shuttles, buses and trucks. Ground access vehicles emissions vary by vehicle and fuel type (gasoline or diesel), travel distance, operating speed, and ambient temperature. 

Outside airport property, these ground access vehicles operate on the local and regional roadway networks while traveling to and from an airport and are difficult to distinguish from background (i.e., non-airport) traffic. 

## B.2.4.1 Methodology 

The EPA has identified 21 HAPs that are designated as Mobile Source Air Toxics (MSATs) to signify those HAPs that are emitted by motor vehicles. $^{58 }$MOVES is currently the best tool for estimating these motor vehicle emissions of MSATs. 59 

The MOVES output is expressed in units of grams/vehicle -mile and can be segregated by vehicle and fuel type (e.g., light duty gas oline, heavy duty diesel, etc.) or combined into a composite value representative of the entire Ground access vehicle fleet. 

