AEDT’s framework incorporates emissions and dispersion modeling functionality from the FAA’s Emissions and Dispersion Modeling System (EDMS). These models are further discussed within this section. 

## 5.1.1. AEDT Development and Architecture 

In 2012, AEDT version 2a (i.e., AEDT 2a) replaced the “legacy” regional noise analysis tool, the Noise Integrated Routing System (NIRS). 17 As such, the primary purpose of AEDT 2a was to model the environmental consequences of air traffic airspace and procedure actions designed and implemented by the FAA’s Air Traffic Organization (ATO). AEDT 2a also included the capability to assess CO$_{2 }$emissions from aircraft main engines. Of note, AEDT 2a is the required model for air traffic airspace and procedure action NEPA analyses. 18 

AEDT version 2b will replace AEDT 2a and the legacy airport air q uality and noise analysis tools - the EDMS and the Integrated Noise Model (INM) . AEDT2b will then become FAA’s single environmental assessment tool for air quality and noise for all projects, including but not limited to airport and airspace NEPA reviews, General Conformity determinations, Planning studies, and Part 150 Noise Compatibility Programs. 

The AEDT user interface and underlying software architecture are distinct from that of EDMS and INM models. AEDT is built on the Microsoft .NET Framework and is capable of running on Microsoft Windows desktop and server operating systems. It is supported by extensive system of relational databases and an ESRI 19 geospatial capability. Input data are entered into AEDT using the user interface, an XML -based AEDT Standard Input File (ASIF), and/or other EDMS/INM model import tools. 

## 5.1.2. AEDT Usage for Air Quality Assessments 

Using AEDT 2b, aviation-related emissions inventories can be computed for the EPA criteria air pollutants (e.g., CO, Pb, NO$_{2}$, O$_{3}$, PM$_{10}$, PM$_{2.5}$, and SO$_{2}$) and their precursors (e.g., NO x and VOCs). Sources of airport emissions included in AEDT 2b encompass aircraft, APUs, GSE, and an array of stationary sources (e.g., boilers, generators, etc.). For this version, the user utilizes the Motor Vehicle Emission Simulator (EPA’s MOVES) 20 model independently of AEDT 2b obtain the necessary data for computing motor vehicle emissions. 

Dispersion modeling can also be conducted within the AEDT interface, based on the results of the emissions inventory and supplemented with meteorological data and the definition receptor sets. Once the necessary data are inputted to AEDT, AEDT internally calls for the EPA AERMOD modeling system to perform the specified dispersion calculations. The resulting 

