Emissions and Dispersion Modeling System Policy for Airport Air Quality Analysis; Interim Guidance to FAA Orders 1050.1D and 5050.4A

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

[Docket No. 29194]

RIN 2120-AC22

Emissions and Dispersion Modeling System Policy for Airport Air

Quality Analysis; Interim Guidance to FAA Orders 1050.1D and 5050.4A

AGENCY: Federal Aviation Administration, DOT.

ACTION: Policy Statement.

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SUMMARY: This document provides a statement of Federal Aviation

Administration (FAA) policy concerning the required use of the FAA

Emissions and Dispersion Modeling System (EDMS) to assess the air

quality impacts of proposed airport development projects. To date, the

EDMS has been considered an FAA preferred model for airport air quality

analysis. The policy statement is intended to ensure consistency and

quality of analysis performed to assess the air quality impacts of

airport emission sources for purposes of complying with the National

Environmental Policy Act of 1969, as amended, 42 U.S.C. 4321 et seq.

(NEPA) and the Clean Air Act as amended, 42 U.S.C. 7401, 7506(c)

general conformity (general conformity) requirements.

EFFECTIVE DATE: April 13, 1998.

FOR FURTHER INFORMATION CONTACT:

Ms. Julie Ann Draper, Analysis and Engineering Branch (AEE-120),

Technology Division, Office of Environment and Energy, Federal Aviation

Administration, 800 Independence Avenue, SW., Washington, DC 20591,

telephone (202) 267-3494.

SUPPLEMENTARY INFORMATION: The EDMS was developed by the FAA in

cooperation with the U.S. Air Force (USAF) in the mid-1980's as a

complex source microcomputer model to assess the air quality impacts of

proposed airport development projects. It has since been the FAA

preferred model for airport air quality analysis. On July 20, 1993, the

Environmental Protection Agency (EPA) accepted the EDMS as a formal EPA

``Preferred Guideline'' model for use in civil airports and

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military bases. In response to the growing needs of the air quality

analysis community and changes in regulations, the FAA in cooperation

with the USAF re-engineered and enhanced EDMS in 1997 to create EDMS

Version 3.0. EDMS Version 3.0 was built under the guidance of a

government and industry advisory board composed of experts from the

scientific, environmental policy, and analysis fields.

The FAA provides guidance on the use of EDMS in FAA Report No. AEE-

AEE-97-03, ``Air Quality Procedures for Civilian Airports and Air Force

Bases,'' which updates and replaces the original version of the

handbook, FAA Report No. FAA-82-21.

The FAA is taking this opportunity to identify EDMS as the required

model to perform the air quality analyses for aviation emission sources

from airport projects instead of the preferred model, as stated in the

FAA's ``Air Quality Procedures for Civilian Airports and Air Force

Bases.'' This policy statement will serve as the interim written

document until the revised FAA Orders 1050, Policies and Procedures for

Considering Environmental Impacts, and 5050, Airport Environmental

Handbook, are published.

Policy Statement

EDMS is designed to assess the air quality impacts of airport

emission sources, particularly aviation sources, which consist of

aircraft, auxiliary power units, and ground support equipment. EDMS

also offers the capability to model other airport emission sources that

are not aviation-specific, such as power plants, fuel storage tanks,

and ground access vehicles.

Except for air toxics or where advance written approval has been

granted to use an equivalent methodology and computer model by the FAA

Office of Environment and Energy (AEE-120), the air quality analyses

for aviation emission sources from airport projects conducted to

satisfy NEPA and general conformity requirements under the Clean Air

Act must be prepared using the most recent EDMS model available at the

start of the environmental analysis process. In the event that EDMS is

updated after the environmental analysis process is underway, the

updated version of EDMS may be used to provide additional disclosure

concerning air quality but use is not required. A complete description

of all inputs, particularly the specification of non-default data,

should be included in the documentation of the air quality analysis for

purposes of complying with NEPA and general conformity requirements.

Users also must provide one copy of EDMS input files used in the

analysis and the corresponding output files to the FAA responsible

official on magnetic media specified by the FAA responsible official.

As stated above, EDMS currently is not designed to perform air

toxic analyses for aviation sources, and may be supplemented with other

air toxic methodology and models in consultation with the appropriate

FAA regional program office. Use of supplemental methodology and models

for more refined analysis of non-aviation sources also is permitted in

consultation with the appropriate FAA regional program office.

This policy is being issued in order to ensure consistency and

quality of analysis performed to assess the air quality impacts of

airport emission sources for purposes of complying with NEPA and

general conformity requirements.

Issued in Washington, DC, on April 6, 1998.

Paul R. Dykeman,

Deputy Director of Environment and Energy.

[FR Doc. 98-9641 Filed 4-10-98; 8:45 am]

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