vehicles transporting airport and tenant employees; and vehicles transporting cargo to and from the airport. 

Air emissions associated with these vehicles are a function of traffic volumes and speeds, distances traveled, vehicle operating characteristics, fuel type, and ambient conditions. 

Computational methods and modeling techniques for assessing ground access vehicles emissions are discussed in Section 6 ( Preparing an Emissions Inventory ) and Section 7 ( Conducting Dispersion Modeling ). For detailed instruction and guidance on how to compute ground access vehicles emissions refer to Appendix A4 ( Ground Access Vehicle Emission Inventory for Criteria Pollutants ). 

## 3.1.5. Stationary and Area Sources 

Stationary and area sources of air emissions at airports consist of both fuel combustion and non- combustion sources. Typical sources include boilers, heaters, generators, snowmelters, incinerators, live-fire training facilities, aircraft engine testing, fuel storage tanks, cooling towers, coating and painting operations, de -icing and anti -icing operations, solvent degreasers and sand/salt piles. 

Air emissions associated with fuel combustion are a function of equipment type, equipment size, fuel type, combustion processes and air emission control measures. Non-combustion sources typically emit evaporative emissions (e.g., fuel storage tanks) and/or fugitive dust emissions (e.g., sand and salt piles). 

Assessment methods and modeling tools for calculating stationary/area source emissions discussed in Section 6 ( Preparing an Emissions Inventory ) and Section 7 ( Conducting Dispersion Modeling ). For detailed instruction and guidance on how to compute stationary/area emissions refer to Appendix A5 ( Stationary Sources Emission Inventory for Criteria Pollutants ). 

## 3.1.6. Construction 

Construction activities are temporary and variable depending on location, duration, and level of activity and are generally confined to a construction site and access/egress roadways. These emissions occur predominantly from the operation of heavy construction equipment ( e.g., backhoes, bulldozers), on- and off-road vehicles used for the transport and delivery of supplies and material (e.g., cement trucks, dump trucks), and on- road vehicles used by construction workers getting to and from a construction site (e.g., cars, pick- up trucks). Construction emissions also include fugitive dust produced from construction materials staging, demolition , and earthwork activities, as well as evaporative emissions from asphalt paving operations. 

Assessment methods and models for calculating construction-related emissions are discussed in Section 6.1.2 ( Airport Construction Emissions). For detailed instruction and guidance on how to compute construction-related emissions refer to Appendix A6 ( Construction Emission Inventory for Criteria Pollutants ). 

## 3.1.7. Other Sources 

Other sources of air emissions associated with aviation, in general, and airports, in particular that are of emerging interest because of their connection to GHG emissions include the following: 

