__________________________________________________________________________________________ 

United States Office of Air and Radiation September 2004 

Environmental Protection 

Agency 

GUIDANCE ON AIRPORT EMISSION 

REDUCTION CREDITS FOR EARLY 

MEASURES THROUGH VOLUNTARY 

AIRPORT LOW EMISSION PROGRAMS 

GUIDANCE ON AIRPORT EMISSION REDUCTION 

CREDITS FOR EARLY MEASURES THROUGH 

VOLUNTARY AIRPORT LOW EMISSION 

PROGRAMS

Prepared by the 

Air Quality Strategies and Standards Division 

Office of Air Quality Planning and Standards 

U.S. Environmental Protection Agency 

Research Triangle Park, North Carolina 27711 

in consultation with the 

Federal Aviation Administration

September 2004

i 
ii
TABLE OF CONTENT 

CHAPTER 1: Introduction ......................................................................................................1

1.1 Purpose of the guidance.....................................................................................1 

1.2 Vision 100 provisions governing airport emission reduction credits.................2 

1.3 Eligibility guidance for the program..................................................................3 

1.4 Description of the contents in this document.....................................................4 

CHAPTER 2: Regulatory Background ....................................................................................7 

2.1 Relationship of the guidance to the Clean Air Act (CAA) ................................7 

2.2 Description of the national air quality management process.............................7 

2.3 General Conformity ...........................................................................................8 

2.4 New Source Review (NSR) ...............................................................................9 

2.5 Economic incentive programs..........................................................................10 

2.6 FAA Inherently Low Emission Airport Vehicle (ILEAV) pilot program .......10 

CHAPTER 3: Criteria for Airport Emission Reduction Credits (AERCs).............................11 

3.1 Quantifiable......................................................................................................11 

3.2 Surplus .............................................................................................................12 

3.3 Federally enforceable.......................................................................................12 

3.4 Permanent ........................................................................................................13 

3.5 Adequately supported ......................................................................................14 

CHAPTER 4: Methodology for Calculating AERCs .............................................................15 

4.1 Baseline development ......................................................................................15 

4.2 Assessment methodology.................................................................................17 

4.2.1 FAA Emissions and Dispersion Modeling System (EDMS)...............17 

4.2.2 Recommended input procedures..........................................................17 

CHAPTER 5: Process for Obtaining AERCs .........................................................................19 

5.1 Airport planning for a low emission program..................................................19 

5.2 Airport program application to the State air quality agency, EPA, and FAA .19 

5.3 Relationship of AERCs to the State Implementation Plan (SIP).....................22 

5.4 FAA approval and program implementation ...................................................23 

CHAPTER 6: Granting and Using AERCs ............................................................................25 

6.1 Granting of AERCs by the State air quality agency ........................................25 

6.2 Life of the AERCs ...........................................................................................26 

6.3 Airport sponsor use of AERCs ........................................................................26 

6.3.1 General Conformity .............................................................................27 

6.3.2 NSR......................................................................................................28 

6.4 Updating, tracking and record keeping............................................................28 

iii 
List of Figures 

Figure 1: Program Application Phase .....................................................................................20 

Figure 2: Project Implementation Phase and Credit ...............................................................24 

APPENDICES 

APPENDIX A: Vision-100, Section 158. Emission Credits for Air Quality Projects 

APPENDIX B: Sample State Air Quality Agency Credit Statement (ACS) to the 

Airport Sponsor 

iv 
List of Acronyms and Terms 

ACS Airport Credit Statement 

AERC Airport Emission Reduction Credit 

AIP Airport Improvement Program 

APU Aircraft Auxiliary Power Unit 

AQ Air Quality 

CAA Clean Air Act 

DOT Department of Transportation 

EDMS FAA’s Emission and Dispersion Modeling System 

EIP Economic Incentive Programs 

EPA Environmental Protection Agency 

FAA Federal Aviation Administration 

GAV Ground Access Vehicles 

GSE Ground Support Equipment 

ILEAV Inherently Low Emission Airport Vehicle pilot program 

MOBILE6 EPA Onroad Emission Model 

NAAQS National Ambient Air Quality Standard 

NON-ROAD EPA’s Off-road Emission Model 

NSR New Source Review 

PFC Passenger Facility Charge 

PGL Program Guidance Letter 

PM Particulate Matter 

PSD Prevention of Significant Deterioration 

SIP State Implementation Plan 

TANKS EPA model to assess emissions of evaporative hydrocarbons from a 

single storage tank 

VALE Voluntary Airport Low Emission program 

Vision 100 The Vision 100—Century of Aviation Reauthorization Act, Public Law 

108-176 

v 
vi
CHAPTER 1 

INTRODUCTION 

The Vision 100—Century of Aviation Reauthorization Act (the Vision 100 Act), 

signed into law in December 20031, establishes a program to reduce emissions from 

airport vehicles, ground support equipment (GSE) and infrastructure at commercial 

service airports in air quality nonattainment and maintenance areas.2 The Vision 100 Act 

directs the Administrator of the Environmental Protection Agency (EPA), in consultation 

with the Secretary of the U.S. Department of Transportation (DOT)/Federal Aviation 

Administration (FAA), to issue guidance on how to ensure that airport sponsors3

 receive 

appropriate emission reduction credits for carrying out projects described in the Vision 

100 Act. 

1.1 Purpose of the guidance 

This document provides guidance on emission reduction credits for voluntary 

early emission reduction programs at airports under the General Conformity and New 

Source Review (NSR) programs. The airport programs are intended to reduce criteria 

pollutants and precursors, improve regional air quality, and accelerate the use of new and 

cleaner technology. 4 

Participation in the program is entirely voluntary for the airport sponsors and the 

State, district, and local air quality agencies. States have the opportunity to realize the 

environmental and public information benefits of early reductions in airport emissions in 

exchange for granting appropriate emission credits to airport sponsors. Airport sponsors 

have the opportunity to apply for FAA Airport Improvement Program (AIP) grants and 

other revenues from passenger facility charges (PFCs) to achieve early emission 

reductions that earn emission credits from State air quality agencies.5 Airport sponsors 

may use the emission credits on airport development projects at a later date to satisfy 

General Conformity and NSR requirements under the Clean Air Act. 

In addition to encouraging airport sponsors to implement early emission reduction 

measures, the EPA and FAA believe that the Vision 100 Act offers other benefits to 

airports, State agencies, and the environment: 

1

 Public Law 108-176, Sections 121 (PFC), 151 (apportionment), 158 (airport emission reduction credits),

and 159 (AIP). 2 49 U.S.C. §§ 40117, 47139, and 47140. Pertains only to criteria pollutants. 3

 “Airport sponsors” are planning agencies, public agencies, or private airport owners/operators that have 

the legal and financial ability to carry out the requirements of the AIP program. The term is also used in

this document to refer to the PFC program, which is restricted to “public agencies.” 4

 Criteria pollutants as defined by the CAA (PM, Ozone, NO2, SO2, CO, Pb). Added benefits may naturally

extend to air toxics. 5

 Includes delegated district, local, and Tribal air quality agencies. 

- 1 -
• Facilitates improved dialog between airport sponsors and air quality agencies, 

• Expedites the environmental review process for airport projects, and 

• Encourages better identification and control of airport emission sources. 

This guidance document imposes no binding or enforceable obligations by EPA. 

Consequently, it does not constitute final agency action by EPA. If airport sponsors and 

State air quality agencies choose to participate in the program, they should fulfill their 

commitments on the basis of this guidance, which is consistent with the Clean Air Act. 

Participating airports would then implement the proposed control measures and 

participating State air quality agencies would provide appropriate emission reduction 

credits. 

In order for FAA to approve funding for the emission reduction measure under the 

Vision 100 Act, it must receive assurance from the State air quality agency that the 

airport sponsor will receive appropriate emission reduction credits. This guidance 

provides information on the granting of that assurance in a form and manner that could be 

used by the airport sponsor and the FAA to enable funding for airport emission reduction 

measures. 

This Vision 100 program is intended to complement existing program eligibility for 

airport compliance with the Clean Air Act.6 Emission reductions generated through this 

program would not change or reduce current airport project requirements to mitigate the 

emissions effects of airport development or otherwise comply with the Clean Air Act. 

1.2 Vision 100 provisions governing airport emission reduction credits 

This EPA document provides guidance on the creation and use of emission 

reduction credits for the Vision 100 program, hereafter referred to as the Voluntary 

Airport Low Emission (VALE) program. With this guidance, no other formal 

agreements or protocols between the airport sponsors and Federal and State agencies 

would be needed for the VALE program. As appropriate, States and airport sponsors 

may use or reference this guidance for other airport emission reduction programs that are 

not within the funding purview of the VALE program. This guidance is not intended to 

preclude other voluntary emission reduction programs and associated reduction credits. 

As specified in the Vision 100 Act, approval of AIP grants or PFC funding for this 

program is contingent upon an assurance to the Secretary of DOT from the State in which 

the project is located (or from the EPA Administrator where there is a Federal 

implementation plan) that the low emission measures of the project will receive 

appropriate emission credits in accordance with this guidance. 

The State’s assurance to DOT/FAA on airport emission reduction credits is a key 

component of the voluntary, incentives-based VALE program. AIP and PFC funding 

may not provide sufficient incentives for early airport emission reductions without 

6 Chapter 5, Section 9(586), “Air and Water Quality Projects,” AIP Handbook, FAA Order 5100.38B, 

Change 1, January 2004.” 

- 2 -
emission credits. The FAA has stated that the lack of emission credits has been a serious 

disincentive for airports to reduce emissions because: voluntary reductions simply 

lowered an airport’s emissions baseline; the impact of subsequent airport development 

projects were judged against the lower baseline; and the airport that had already reduced 

emissions had fewer options for producing more reductions for new airport development 

projects. For these reasons, airport sponsors have reportedly deferred emission 

reductions until needed at the time of development projects. 

The Vision 100 Act directs the Administrator of EPA to issue guidance with the 

following conditions: 

 The provision of credits is consistent with the Clean Air Act; 

 Credits generated by the emission reductions are kept by the airport sponsor and 

may only be used for purposes of any current or future general conformity 

determination under the Clean Air Act or as offsets under EPA’s new source 

review program for projects on the airport or associated with the airport; 

 Credits are calculated and provided to airports on a consistent basis nationwide; 

 Credits are provided to airport sponsors in a timely manner; 

 A method is established to assure the Secretary of Transportation that, for any 

specific airport project for which funding is being requested, the appropriate 

credits will be granted.7 

In accordance with Vision 100 and AIP and PFC funding requirements, emission 

reduction credits for the VALE program may only be obtained and used by airport 

sponsors. In addition, under FAA requirements, sponsors may not transfer or trade such 

credits to airport tenants or operators, other airports, or any other entity. 

The Vision 100 Act does not require States to grant emission credits to airports. 

However, voluntary airport ground emission reduction projects would not be funded by 

FAA under the Vision 100 Act where States do not provide appropriate emission credits 

in accordance with this guidance.8 

1.3 Eligibility guidance for the program 

The FAA is providing program and technical guidance for airports to use in 

planning their low emission projects and in determining the eligibility of project 

measures.9

 This guidance includes a Program Guidance Letter (PGL) on airport and 

project eligibility for the overall program and another PGL for the special AIP pilot 

program established under the Vision 100 Act for evaluating the use of cleaner 

conventional fuel and retrofit technology on aircraft ground support equipment at ten 

airports.10 

7 49 U.S.C. 47139(a) (1)-(5) 8 49 U.S.C. 47139(b). 9

 VALE Technical Report available from FAA at: www.faa.gov/arp/environmental/vale 10 Vision 100, Section 159, Low-Emission Airport Vehicles and Infrastructure. 

- 3 -
Sponsors of commercial service airports in air quality nonattainment and 

maintenance areas may apply to the FAA for AIP grants or to collect and use PFCs to 

assist in funding the acquisition or conversion of airport-dedicated ground transportation 

vehicles and aircraft ground support equipment to low emission technologies. AIPfunded low emission technologies would perform to the best achievable low emission 

standards established by the EPA and rely exclusively on alternative fuels that are 

substantially non-petroleum based as defined by the U.S. Department of Energy (DOE), 

but not excluding hybrid systems or natural gas powered vehicles. 11,12 PFC funding is 

more flexible and may also be used for technologies using cleaner conventional fuels 

with emission control technologies certified or verified by EPA. 

In addition to low emission vehicles, AIP grants and PFC funding for this 

program could be used for supporting airport infrastructure, such as refueling or 

recharging stations and airport terminal gate electrification to provide power and air to 

parked aircraft. As long as airport safety and security are assured, limited public access 

to airport refueling or recharging stations could be allowed. 

The FAA technical guidance for this program is being developed in consultation 

with the EPA, DOE, other Federal agencies, the aviation community, industry, and the 

public. This guidance provides airport sponsors and others with detailed information on 

various aspects of the program, including: 

 Allowable alternative fuels and clean conventional fuels 

 Allowable infrastructure to reduce emissions 

 Low emission vehicle performance standards 

 Emission assessment and cost-effectiveness methodology 

 Airport and vehicle use commitments 

 Public access to refueling and recharging stations 

 Reporting and monitoring requirements 

The FAA plans to distribute all of the published guidance documents to airports 

and State air quality agencies to encourage their participation in the program and to 

facilitate the planning, application, and implementation phases of the program. 

1.4 Description of the contents in this document 

The following chapters of this guidance document explain the recommended 

process and criteria for airports to obtain and use emission reduction credits under the 

program. Chapter 2 outlines the regulations that support and authorize the creation of 

early emission reduction programs. Chapter 3 discusses the criteria for early emission 

11 As defined by DOE, “alternative fuels” are substantially nonpetroleum and yield energy security and 

environmental benefits. Under the Energy Policy Act of 1993 (EPAct), DOE recognizes the following

alternative fuels: methanol, ethanol, and other alcohols; blends of 85% or more of alcohol with gasoline;

natural gas and liquid fuels domestically produced from natural gas; liquefied petroleum gas (propane);

coal-derived liquid fuels, hydrogen and electricity; biodiesel, and “P-series” fuels (see

www.eere.energy.gov/vehiclesandfuels/epact/ epact_fuels.shtml) 12 49 U.S.C. §47102(11)

- 4 -
reduction programs and associated credits. Chapter 4 addresses the methods for 

assessing and quantifying emission reductions. Chapter 5 discusses the process that 

airports and State air quality agencies should follow when creating an early emission 

reduction program. This process includes the procedures used by airport sponsors to 

apply for credits, to quantify and document emission reductions, and to verify the 

ongoing benefits of their low emission programs. Finally, Chapter 6 explains how airport 

sponsors could apply their emission reduction credits in the future toward their regulatory 

requirements and the limits that would apply to such use. 

There are two appendices to this report. Appendix A contains Section 158 of the 

Vision-100 FAA reauthorization bill that mandates this guidance document. Appendix B 

is a sample credit statement by the State to the airport sponsor awarding numerical 

credits. 

- 5 -
- 6 -
CHAPTER 2 

REGULATORY BACKGROUND 

The Clean Air Act (CAA)13 governs air quality control by directing Federal, State, 

and local agencies to regulate air pollution activities by industries and individuals. The 

following is a brief discussion of relevant sections of the CAA that relate to the 

development of emission reduction programs. 

2.1 Relationship of the guidance to the Clean Air Act (CAA) 

This document provides guidance to State air quality agencies, airports, and the 

general public on how early control measures to reduce airport emissions may be used to 

meet general conformity and new source review (NSR) requirements. Participation in the 

VALE program does not affect or change obligations under CAA provisions or 

implementing regulations. General conformity requirements can be found in Section 

176(c) of the CAA. NSR requirements can be found in sections 160 through 169, 172, 

and 173 of the CAA. 

This guidance document under the Vision 100 Act addresses both general 

conformity and NSR requirements for airports. Airport sponsors and State air quality 

agencies that choose to participate in the program would be subject to the Vision 100 

Act’s requirements on airport emission reduction credits that are explained in this 

document. Participating airports are also bound by FAA compliance regulations for the 

AIP and PFC programs, which are described in FAA Order 5100.38B and related 

guidance documents. 

2.2 Description of the national air quality management process 

Section 109 of the CAA requires EPA to set national ambient air quality standards 

(NAAQS) for pollutants considered to be harmful to human health or the environment. 

EPA has established standards for six pollutants known as “criteria” pollutants. They 

include carbon monoxide, nitrogen dioxide, ground level ozone, lead, particulate matter 

(PM10 and PM2.5)

14, and sulfur dioxide. 

Under the provisions of Section 107 of the CAA, EPA designates areas as 

attainment, nonattainment, or unclassifiable for the criteria pollutants. The EPA and 

FAA have prepared an updated list of U.S. commercial service airports that are located in 

nonattainment or maintenance areas and that are eligible for the VALE program.

15 

1342 U.S.C. 7401 et seq 14 PM 10 is defined as “particles with Aerodynamic Diameter Less than or Equal to a Nominal 10 

micrometers.” PM 2.5 is defined as “particles with Aerodynamic Diameter Less than or Equal to a Nominal 

2.5 micrometers.” 15 Available at: www.faa.gov/arp/environmental/vale. 

- 7 -
Under Section 110 of the CAA, States are directed to develop plans that provide 

for the implementation, maintenance and enforcement of the NAAQS within their States. 

These plans are known as State implementation plans (SIPs). If monitoring data indicate 

that an area is not meeting the standards, EPA will designate the area as nonattainment.16 

If an area is designated nonattainment, the State must then revise its SIP to show how it 

will reduce emissions so that it will attain the NAAQS within that area. Once a 

nonattainment area attains the NAAQS, the area is considered to be a maintenance area. 

States must revise their SIPs to show how the maintenance areas will maintain 

compliance with the NAAQS for at least 20 years after the area achieves attainment. 

2.3 General Conformity 

Section 176(c) of the CAA17 requires that EPA adopt regulations to ensure that 

projects sponsored by Federal agencies do not interfere with a State’s ability to meet or 

maintain the NAAQS. In order to fulfill the CAA requirements, EPA promulgated the 

Transportation Conformity Regulations on November 24, 199318 and the General 

Conformity Regulations on November 30, 1993.19 The Transportation Conformity 

Regulations address highway and mass transit transportation plans, programs, and 

projects funded under title 23 U.S.C. or the Transit Act. The General Conformity 

Regulations20 are applicable to all other Federal projects and actions, including FAA 

actions for airport development. 

The General Conformity Regulations prevent Federal agencies from taking 

actions in nonattainment and maintenance areas that increase emissions in violation of the 

SIP. Compliance with the General Conformity Regulations can be achieved in several 

ways, including: 

 Documenting that planned emission increases are included in the existing SIP; 

 Persuading the State to include the emission increases in the SIP; 

 Offsetting emission increases with concurrent emission decreases of the same 

size; and 

 Mitigating the emissions. 

All Federal actions are subject to general conformity requirements unless 

otherwise exempt. Examples of exempt actions include: 

 Actions covered by the Transportation Conformity Regulations; 

 Actions with total direct and indirect emissions below specified de minimis 

levels; 

16 Under Section 107 of the CAA, EPA designates areas as attainment or nonattainment for criteria 

pollutants. 17 42 U.S.C. 7506(c)

58 FR 62188-62253 19 58 FR 63214-63259. 20 40 CFR 93. 150-160 

- 8 -

7 
 Actions specifically listed in the rule as exempt; or 

 Actions included on any list of “presumed to conform” actions published by 

FAA.21 

Most of the air quality requirements for airports are associated with the General 

Conformity Regulation. Under General Conformity, this program can help the FAA to 

demonstrate that a proposed project is either exempt or conforming with the SIP. 

Airports are encouraged to take immediate measures to reduce emissions by allowing 

them to carry these early emission reductions forward on an annual basis (see Chapter 6) 

as if they were planned as part of a future airport development project. 

2.4 New Source Review (NSR) 

New and modified stationary sources at airports are sometimes subject to 

requirements of EPA and State new source review (NSR) programs. Possible examples 

of airport sources subject to NSR include airport power plants and painting and 

maintenance facilities. 

The basic requirements of the NSR program are established under Parts C and D 

of Title I of the CAA. Generally administered by State air quality agencies, the NSR 

program is a means to control air emissions from new or modified stationary sources by 

requiring pre-construction review and the use of air pollution control technology or other 

emission reduction strategies. The NSR program is comprised of three permitting 

programs: 1) minor sources located in attainment, unclassified, or designated 

nonattainment areas (minor source NSR), 2) major stationary sources located in 

designated nonattainment areas (nonattainment NSR), and 3) major sources located in 

attainment or unclassified areas (Prevention of Significant Deterioration or PSD). 

The nonattainment NSR permit program only applies to construction projects that 

will result in potential emissions that exceed certain thresholds. For new sources the 

potential emissions must exceed the levels that make it a “major” source. The “major” 

thresholds vary by pollutant and by the degree of nonattainment for the area in which the 

source is located (based on the sources potential to emit from 100 tons per year down to 

10 tons per year). For modifications (a physical change or change in the method of 

operation) to existing major sources, the modification must result in a “significant” net 

increase in emissions for the NSR requirements to be triggered. Under this program, the 

owners or operators for new or modified major stationary sources must install control 

technology representing the lowest achievable emission rate and offset any emission 

increases above baseline emission levels. Emission reduction credits from the VALE 

program can be used as offsets for the emission increases. 

The PSD program applies to new or modified major stationary sources located in 

areas that are meeting the NAAQS for at least one criteria pollutant, including areas 

designated as maintenance areas. The PSD program also applies to new or modified 

21 40 CFR 93.153-160. 

- 9 -
major sources of non-criteria pollutants regulated under the CAA, except for hazardous 

air pollutants listed and regulated under section 112 of the CAA. Under the PSD 

program, a source is considered major if it is in one of the 28 named source categories 

and emits or has the potential to emit 100 tons per year, or is not in the named categories 

and emits or has the potential to emit 250 tons per year of a PSD regulated pollutant. 

2.5 Economic incentive programs 

Section 182 of the CAA allows States to achieve an air quality objective by 

developing market-based incentive programs to reduce emissions. By providing sources 

with flexibility in meeting an emission reduction goal, economic incentive programs 

(EIPs) create opportunities to find the most suitable and cost effective means to fit the 

circumstances. 

An early emission reduction program is one form of an EIP. Economic incentives 

for early reductions can result in greater long-term emission reductions and in earlier 

development of innovative technologies. The EPA guidelines for EIPs are published in 

the document, Improving Air Quality With Economic Incentive Programs.

22 The 

emission reduction credit guidance in this document for the VALE program is consistent 

with the EIP guidance. 

2.6 FAA Inherently Low Emission Airport Vehicle (ILEAV) pilot program 

Based on Section 158 of the Vision 100 Act (Previously Approved Projects),23 the 

ten airport sponsors participating in the FAA ILEAV Program (Section 47136) may apply 

to the States for and receive emission reduction credits under this guidance for all 

emission reductions produced by the airports through the ILEAV program, including 

airport projects previously approved under 49 U.S.C. §47136. Since the ILEAV funding 

approval has already been granted, airport sponsors of ILEAV projects may be at the 

project implementation phase and may be eligible to apply for airport emission reduction 

credits. The ILEAV program is the only previous program that the Vision 100 Act 

identifies as being eligible for airport emission reduction credits under this program. No 

other previous airport low emission activities have been identified for emission reduction 

credits through the VALE program. 

22 Improving Air Quality with Economic Incentive Programs (EPA-452/R-01-001, January 2001 23 49 U.S.C. 47139(c). 

- 10 -
CHAPTER 3 

CRITERIA FOR AIRPORT EMISSION REDUCTION CREDITS (AERCs) 

Approved measures for early emission reductions, which can be applied by the 

airport sponsor to general conformity or NSR permit requirements, cannot interfere with 

other requirements of the CAA and must be consistent with SIP attainment, maintenance, 

and progress requirements24. 

To be eligible for airport emission reduction credits (AERCs), the emission 

reductions would need to meet the quantifiable, surplus, enforceable, and permanent 

criteria specified in EPA guidance for SIP development. This guidance also follows the 

Voluntary Mobile Source Emission Reduction Program and the Voluntary Stationary 

Source Guidance25, 26 and includes an additional criterion that the airport sponsor’s 

VALE program is adequately supported. 

3.1 Quantifiable 

The emission reductions from an approved activity are quantifiable if they can be 

reliably calculated and if the method of calculation can be replicated. The airport sponsor 

would need to provide the State air quality agency with sufficient data and information to 

enable the agency to replicate the calculations if it chooses to do so. 

Airport sponsors should calculate emission reductions for each year of the project 

(i.e., the useful life of the purchased low emission equipment or systems). Airport 

sponsor quantification of emission reductions would need to be completed before the 

State air quality agency could determine if the measure is eligible and provide written 

assurance to FAA that AERCs could be granted. The FAA has stated that it must receive 

this written assurance before it can approve project funding. Airport sponsors may need 

to update their initial program application emission reduction estimates in the future to 

reflect changes in funded measures, planned operations, commercially available 

technology, or Federal or State regulations. 

The Emission and Dispersion Modeling System (EDMS) is the FAA-required 

methodology for airport air quality analysis of aviation sources: aircraft, auxiliary power 

units, and ground support equipment. 27 For the VALE program, the FAA requires the 

airport sponsor to calculate the baseline and project emissions from project-related airport 

24 Specific terms for progress requirements are called reasonable further progress/rate of progress 

(RFP/ROP). 25 The Voluntary Measures Policy should be consulted if SIP revisions or SIP credits are sought under this

policy. A description of this policy is available at the following web site: 

http://www.epa.gov/otaq/transp/traqvolm.htm. 26 Memorandum: Guidance on incorporating Voluntary Mobile Source Emission Reduction Programs into

the SIP, October 24, 1997. 27 FAA Orders 1050.1E, 5050.4B, and Air Quality (Handbook) Procedures for Civilian Airports and Air 

Force Bases, version 1c, 2004. 

- 11 -
sources using EDMS.28 Airport sponsors may supplement or refine their EDMS analysis 

of non-aviation sources using other EPA guideline models, such as MOBILE 6 for onroad vehicles (see Chapter 4 for more detailed discussion of the assessment 

methodology). 

3.2 Surplus 

Creditable emission reductions would be reductions not otherwise required by 

Federal, State or local regulations, and for which emission reduction credit has not 

already been taken. Such reductions could generally be used as long as they are not 

otherwise relied on to meet other applicable air quality attainment and maintenance 

requirements. 

In evaluating if the AERCs are surplus, the State should compare a project 

baseline against the proposed project action (see Section 4.1, Baseline development). 

The net difference between baseline and project scenarios represents the amount of 

emission reductions that may be surplus and creditable. 

Future emission standards for new vehicles would not affect the surplus status of 

VALE emission reductions and AERCs. The main reason for this is that new standards 

would not impose a requirement to purchase replacement vehicles. However, the airport 

sponsor and State air quality agency need to consider factors that could influence the 

surplus status of projected emission reductions over time. For example, new Federal 

emission standards that require retrofitting of existing vehicles could decrease the surplus 

status of related emission reduction measures. Conversely, it is possible that surplus 

reductions could increase, for example, if a State deleted specific control measures from 

the SIP. 

The surplus criterion is not disadvantageous to an airport sponsor making early 

voluntary reductions because AERCs ultimately available for use would not be less than 

if the sponsor waited to implement the emission reduction strategies in the future as part 

of a project development. 

3.3 Federally Enforceable 

Credited emission reduction measures must be enforceable at the Federal and State 

levels.29 AERC emission reduction measures would generally be considered Federally 

enforceable if they meet all of the following requirements: 

 The measures are independently verifiable. 

 A complete schedule to implement and verify approved measures has been 

adopted by the airport sponsor in accordance with AIP and PFC guidelines. 

28 “Project-related airport sources” are directly related to the sponsor’s VALE project and do not include 

other or all airport emission sources. 29 See § 110(a)(2)(A) of the CAA (42 U.S.C.§7410(a)(2)(A)) 

- 12 -
 Violations of AERC requirements are practicably enforceable in accordance with 

the Clean Air Act, EPA regulations, and FAA AIP and PFC regulations and grant 

assurances. 

 Liability for violations can be identified. 

 All required airport emissions-related information is made publicly available. 

In addition, AERCs used as offsets for sources subject to NSR regulations must 

meet the enforceability requirements of NSR regulations. 

Verification of airport program implementation relies on the established FAA 

compliance programs for the AIP and PFC programs. These compliance programs have 

been in place for many years and have a strong record of effectiveness. Airport sponsors 

are required to provide the FAA with numerous grant and program assurances that 

Federal funds are being applied in accordance with the applicable laws, regulations, and 

program guidance.30 In addition to the standard assurances and reporting requirements, 

airport sponsors would also need to meet any special grant assurances that the FAA adds 

to the VALE program. 

If AERC measures are not implemented, the State air quality agency can void 

related AERCs. The State may choose also to incorporate airport emission reduction 

measures into the SIP to ensure State and EPA enforceability. An appropriate time to do 

this, for instance, would be following FAA project funding and the airport sponsor’s 

submission of an updated emissions reduction report to the State for AERCs.31 The State 

may include the AERC measures directly in the SIP by adopting and submitting a SIP 

revision or by issuing a permit for the measure as part of an approved SIP permit program 

(see section 5.3). 

3.4 Permanent 

Emission reductions that are credited need to be “permanent” in that they continue 

to occur at the estimated level throughout the lifetime of the VALE vehicles and 

infrastructure. The FAA addresses this requirement through grant and program 

assurances in the AIP and PFC programs. While infrastructure improvements and capital 

assets are permanent by design, the FAA expects that the VALE program will also 

include a special condition, similar to the existing FAA ILEAV pilot program, stating 

that low emission vehicles funded under the AIP and PFC programs would be maintained 

and used for their useful life at the airport for which they were purchased.32 In the event 

that program funds are used to assist parties other than the airport sponsor, the FAA plans 

to require the airport sponsor to enter into agreements with the purchasing party that 

requires that the vehicles be maintained and used at the airport for their useful life. 

30 List of airport assurances are listed on the FAA Airports Office web site at: 

http://www.faa.gov/arp/financial/aip/assurances.cfm. 31 The Voluntary Measures Policy, http://www.epa.gov/otaq/transp/traqvolm.htm. 32 Estimates of vehicle “useful life” are provided in the VALE Technical Report. 

- 13 -
Another special condition for the VALE program is the FAA requirement33 that 

any vehicles or equipment replaced under the program, whether airport or privately 

owned, cannot be transferred to another airport or location within the same or any other 

nonattainment or maintenance area. This requirement protects regional air quality, 

prevents adverse effects on other sensitive locations, and eliminates the possibility of 

duplication of VALE funding for the same vehicles or equipment that have been moved 

to other locations. 

In order to assure a permanent stream of emission reductions based on the 

operational forecast of vehicle and equipment use, the airport sponsor should use and 

maintain program vehicles and equipment in a consistent manner with their usage 

estimates. New cleaner vehicles and equipment should be operated as planned even if 

old systems are still available. The airport sponsor should develop and maintain usage 

records and periodically update their annual emission reduction estimates if usage or 

other factors change that could affect estimated emission reductions. 

3.5 Adequately supported 

The airport sponsor should demonstrate that it has adequate funding, personnel, 

and other resources to implement and verify the approved low emission measures on 

schedule. 

33 Voluntary Airport Low Emission Program Technical Report, Chapter 3, FAA, September 2004. 

- 14 -
CHAPTER 4 

METHODOLOGY FOR CALCULATING AERCs 

Emission reductions are usually quantified as a rate-based number (weight per 

unit of time). The rate-based approach to calculating emission reduction credits results 

in a permanent, continuous stream of reductions over time. Under the rate-based 

approach, emission reductions for the VALE program would be computed and tracked 

for criteria pollutants on an annual basis in pollutant tons per calendar year. AERC used 

for NSR offsets should also meet all the Clean Air Act requirements for NSR creditable 

offsets. 

In the simplest form, AERCs would be based on the net surplus reductions 

between existing baseline emissions and project emissions from implementation of 

proposed measures. This comparison is limited to the project-related low emission 

vehicles and equipment and would not require the airport sponsor to perform an analysis 

or inventory of non-project or total airport emissions. 

Airport sponsors may incorporate into their project, and receive AERCs for, the 

emission reductions of vehicle and equipment not funded by either AIP or PFC, if these 

source reductions are part of the overall VALE project (e.g., conversions of vehicles or 

equipment with airport revenue or private sector funding that utilize a VALE alternative 

fueling or recharging station owned by the airport). Accounting for these additional 

emission reductions should be based on the proportion of reductions that are directly 

related to the VALE program and can be supported with documentation. The airport 

sponsor may not claim emission reductions for non-airport dedicated, on-road vehicles 

that are considered part of metropolitan transportation plans and transportation 

improvement programs reflected in the transportation conformity process. 

4.1 Baseline development 

Baseline emissions would be considered to be the lower of the actual or allowable 

emissions, whichever is less, from the project-related equipment (see discussion of 

allowable emissions below). Most mobile source baselines should be based on what 

emissions would have occurred if the voluntary emission reduction measure was not 

implemented.34 

The baseline-project comparison for mobile sources will either be “old vs. new” 

or “new vs. new.” In the first type of comparison, when existing vehicles are being 

converted or retired (old vs. new), airport sponsors should establish the emissions 

baseline using historical records of vehicle operations for the most recent and 

representative two-year period available. Developing the correct baseline for an actual 

piece of equipment that is being replaced would require such information as its hours of 

operation per month, remaining useful life, and emission factors. In the event that the 

airport sponsor lacks adequate historical usage records and quantification of the baseline 

34 EPA 452/R-01-001, Section 16.3.4.a(1). 

- 15 -
emissions is more difficult, a minimum (i.e., conservative) estimate of baseline usage 

should be developed using typical operating data for similar equipment at the airport. 

In the second type of comparison (new vs. new), the airport sponsor may be 

proposing to purchase new low emission vehicles because of airport growth. These low 

emission vehicles are in lieu of purchasing new conventional (gasoline or diesel) fuel 

vehicles. The appropriate baseline in this case would be the certified or equivalent (e.g., 

modeled) emission levels of comparable new conventional fuel vehicles. 

For purposes of this program, the airport’s baseline emission levels should reflect 

the allowable requirements and emission levels that should exist at the airport. Allowable 

requirements refer to any restricted levels of airport emissions that are part of the SIP or 

other existing Federal, State, or local requirements and standards. At present, there are 

relatively few special State agreements that might affect the determination of allowable 

airport emissions. In addition, it should be noted that States sometimes do not identify 

airport sources separately in their SIPs, electing to count airport emission sources in their 

allocations for mobile, stationary, and construction sources. 

Below are three examples to clarify the appropriate baseline comparison: 

Example 1 (Old vs. New for Replacement). An airport sponsor is replacing a gasoline 

vehicle with six remaining years of useful life. In this case, the airport sponsor uses an 

“old vs. new” comparison for the first six years and a “new vs. new” comparison (see 

Example 2) thereafter for the estimated useful life of the new vehicle. 

Example 2 (New vs. New for Growth). An airport sponsor is adding a new electric 

vehicle instead of a new conventionally fueled vehicle. The calculated net difference in 

emissions between the new electric vehicle and the equivalent new conventionally fueled 

vehicle is determined at the time of purchase (i.e., current year) and is extended for the 

useful life of the new vehicle.35, 36 

Example 3 (Old vs. New for Replacement with Future Retrofit Adjustment). An airport 

sponsor decides to replace diesel on-road maintenance equipment with electric equipment 

and receives credit for the PM emission reductions. The estimated and credited 

reductions for the current and future years (after retrofit is required) should be adjusted to 

equal the difference between the electric equipment and the diesel equipment with the 

particulate traps. 

 Regarding EPA “fleet average” standards for light-duty on-road vehicles, emission factors for new 

conventional fuel vehicles should based on the average between VALE low emission standards and the 

highest EPA Tier II Bin level. This applies to light and medium-duty airport vehicles (VALE categories 1 

and 2). For EPA “phase-in” of on-road heavy-duty vehicle fleet standards in 2007 to 2010 (VALE vehicle 

category 3), emission differences should be adjusted to reflect the percentage of phase-in required each 

year. (See VALE Technical Report for discussion of program vehicle standards and assessments). 36 Under the NSR program, only emission reductions from replacement of old equipment would be 

creditable. 

- 16 -

35
4.2 Assessment methodology 

The following procedures should be observed when calculating emissions 

reductions. 

4.2.1 FAA Emissions and Dispersion Modeling System (EDMS) 

The FAA requires37,38 airport sponsors to use EDMS to calculate all emissions at 

the airport related to the VALE program. This includes aviation sources, namely aircraft, 

APUs, and GSE, as well as ground access vehicles (GAV) and various stationary sources 

located at the airport. Airports may choose to supplement EDMS calculations for nonaviation sources with approved EPA emission models such as MOBILE 6 for on-road 

vehicles, NON-ROAD for off-road vehicles, and TANKS for evaluating evaporative 

emissions from single fuel storage tanks. 

The VALE program is being supported by dedicated FAA enhancements to 

EDMS that are designed to: 1) simplify airport applications for the program; 2) increase 

the accuracy of emission assessments; and 3) standardize output reports for improved 

Federal and State agency review.39 

In developing their projects, airport sponsors should use the most recent version 

of EDMS and other EPA approved models. This general approach should be followed at 

logical intervals in the future to take advantage of model improvements. In the event that 

follow-on projects to an earlier project demand modeling consistency, an airport sponsor 

may stay with the original version of a model(s) if a clear rationale is provided. In all 

cases, the same version of EDMS and other models should be used to calculate emissions 

for both the baseline and project scenarios. Emission reductions and AERCs obtained 

using one version of the model would not need to be re-calculated each time a new 

version of a model is released. 

4.2.2 Recommended input procedures 

Conservative assumptions and consistent inputs are critical to effective analysis. 

Conservative assumptions, which err on the side of underestimating emission reduction 

benefits, should be used in developing modeled inputs wherever uncertainties exist. In 

line with this, activity levels for baseline and future scenarios should be the same,

40 

unless there is a supportable forecast that vehicle and equipment fleets or usage rates will 

change in the future. Areas of potential uncertainty should be identified and described in 

the airport sponsor’s reports whenever possible (e.g., vehicle emission factors).41 

37 FAA Order 1050, Change 4. “Emission and Dispersion Modeling System for Airport Air Quality 

Analysis, 63 FR 18068 – 18069. 38 Voluntary Airport Low Emission Program Technical Report, Section 1.7.4, FAA, September 2004 39 See information on new EDMS Version 4.2 at: www.aee.faa.gov/emissions/EDMS/EDMShome.htm., 

including description of dedicated V4.2 enhancements for the VALE program. 40 EPA-452/R-01-001, 4.1 (b) or 16.3.4. 

41 EPA-452/R-01-001, 6.4. 

- 17 -
Airport sponsors have the option to perform emission measurements of operating 

program vehicles and equipment in order to refine their emission reduction estimates. 

The emission reduction analysis should carefully consider factors that will change 

emission reduction estimates year-to-year and whether these reductions continue to be 

surplus. It is possible that AERCs (i.e., surplus status of emission reductions) may 

diminish with time depending on the schedule of new Federal emission standards. 

Operational factors include the number of vehicles, fleet mix, vehicle operations or usage 

rates, and the useful life of current and new equipment. The modeled emission factors 

are expected to account for vehicle deterioration rates automatically. Emission reduction 

estimates may also be affected by organizational factors such as funding and schedule 

modifications or the financial status of airlines and other non-airport participants. 

- 18 -
CHAPTER 5 

PROCESS FOR OBTAINING AERCs 

5.1 Airport planning for a low emission program 

The AERC process begins when an eligible commercial service airport

42 in a 

designated nonattainment or maintenance area decides to develop a voluntary early low 

emission program and apply for AIP and/or PFC funding. Airport planning for this low 

emission program should adhere to FAA VALE program guidance on allowable activities 

and equipment. The proposed airport program should be tailored to the local air quality 

problems causing the area’s nonattainment or maintenance status. 

As early as possible, the airport sponsor should contact Federal and State agencies 

to inform them of the airport’s interest and to obtain needed information. For example, 

State air quality agencies can verify nonattainment and maintenance classifications for 

the area. These agencies can also describe how an airport early reduction program may 

be related to the SIP and whether there are any provisions in the SIP or supplemental 

agreements that could affect the airport’s proposed program. EPA Regional Offices can 

provide additional help in answering questions on General Conformity and this AERC 

guidance. FAA Regional Airports Division and Airport District Offices (hereafter 

referred to as “FAA regional offices”) can provide guidance on the use of PFC and AIP 

funds to support the proposed low emission activities. 

There are several important reasons for airport sponsors to take enough time in 

the early stages of the process to develop a comprehensive and long-range plan for their 

low emission program. Airport sponsors should plan VALE projects to coincide with the 

anticipated year(s) of elevated airport emissions resulting from construction and/or 

operational activities. Other considerations are the limited resources of agencies and the 

annual cycle of FAA project reviews and funding approvals, which typically involves 

multi-year acquisitions through AIP and PFC programs. For these reasons, the FAA 

recommends that interested airport sponsors submit no more than one VALE program 

application per year. 

On the basis of early discussions, the State air quality agency can be expected to 

work with the airport sponsor to develop a program that is consistent with the SIP and 

other Federal and State air quality requirements. At any point in the process, the FAA 

and EPA regional offices are available to discuss the applicability and feasibility of 

proposed low emission projects and to provide information about other airport emission 

reduction programs throughout the country that may be useful models. 

5.2 Airport program application to the State air quality agency, EPA, and FAA 

Based on program guidance and discussions with the appropriate agencies, the 

airport sponsor begins the formal application process (see Figure 1) by preparing a 

42 Listed in the FAA National Plan of Integrated Airport System (NPIAS) 

- 19 -
program proposal for State, EPA, and FAA review. This proposal should not be highly 

complex or lengthy but should provide all of the needed elements of information, 

including: 

 Description of program measures. This includes specific information on the 

proposed low emission vehicles, the replaced/displaced conventional fuel 

vehicles, supporting infrastructure and equipment such as refueling and 

recharging stations, how the equipment will operate, and the expected deployment 

and useful life for each unit of equipment. 

 Emission savings estimates. The airport sponsor should quantify the expected 

emission reductions from the program (in tons per calendar year per criteria 

pollutant) and cite the methods and models used to obtain these estimates (see 

Chapter 4) 

 Confirmation that the projected emission savings meet CAA requirements – 

quantifiable, surplus, enforceable, permanent and adequately supported (see 

Chapter 3). Confirmation should include the airport sponsor’s proposed approach 

to project tracking and record-keeping over the life of the program. 

 Relationship with State air quality plans. As part of the airport sponsor’s showing 

that the early emission reductions program is surplus, the airport sponsor should 

consult with the State air quality agency to identify what, if any, provisions in the 

SIP or other state agreements would affect the proposed measures or the airport 

calculation of emission benefits. 

Figure 1 

Program Application Phase 

Documents 

Actions 

Airport Air Quality Proposal 

• Description of project measures 

• Emission reduction estimates 

• Confirmation that emission reductions are quantifiable, surplus, 

enforceable, permanent 

• Relationship with State air quality plans 

Preliminary State 

AQ agency and EPA 

review 

Application to State & 

EPA for AERCs Application to FAA for 

AIP/PFC funding 

FAA funding 

approval of 

proposed measures 

- 20 -
The airport sponsor should submit its program proposal concurrently to the State 

air quality agency, the EPA Regional Office, and the FAA regional offices for review. 

The State air quality agency and EPA should review the airport sponsor’s proposal to 

ensure that project information and descriptions are understandable, that the calculations 

are reasonable, and that the projected emission reductions meet the quantifiable, surplus, 

enforceable, permanent, and adequately supported criteria defined in Chapter 3 of this 

guidance. The State air quality agency may request further information or clarification 

from the airport sponsor to complete its review on a timely basis. 

State air quality agencies should consider the VALE program to be independent 

of other State and local programs or agreements, particularly if such activities involve 

areas besides criteria pollutants (e.g., air toxics, other environmental impact areas). 

VALE projects and AERCs should be evaluated solely on the basis of the VALE project, 

independent of other State or local goals, agreements, or issues. Likewise, the VALE 

program should not preclude or affect other State and local agreements (e.g., the Port of 

Seattle and Puget Sound Clean Air Agency MOA) if VALE funding is not involved. 

The State air quality agency should consider any comments submitted by the EPA 

on the proposed emission reduction measures and associated AERCs. State and EPA 

reviews should be concurrent. The EPA should provide its comments within the State 

comment period to the State air quality agency with copies to the airport sponsor and 

FAA regional offices. 

The Vision 100 Act requires that the credits be provided to the airport sponsors in 

a “timely manner.” Although no specific time period is identified in the law EPA 

believes that it would be reasonable for a State air quality agency to attempt to respond to 

the airport sponsor’s proposal within 45 calendar days by providing a letter of assurance 

to the FAA (the recommended letter is provided in Appendix G of FAA Voluntary 

Airport Low Emission Program Technical Report). Likewise, EPA also believes that 

subsequent State reviews for AERCs should occur within a similar 45 calendar day 

period. 

As detailed in the VALE Technical Report, the AIP and PFC programs are 

administered by FAA regional offices and the Airports Financial Assistance Division 

(APP-500). FAA agency review of airport capital improvement plans begins in the 

previous fiscal year, leading up to selection and approval of projects for implementation 

early in the 2nd quarter of the current fiscal year. Because AIP and PFC planning and 

programming schedules are tight, a delay by the State in its review and letter of AERC 

assurance to the FAA could jeopardize an airport sponsor’s ability to obtain funding for a 

VALE project in the current fiscal year, representing a project delay for the airport 

sponsor of at least one year. 

As the funding agency, the FAA review of the airport sponsor’s proposal would 

focus on the project cost effectiveness of the proposed emission reduction strategies as 

well as other requirements of the program. The FAA may request additional information 

- 21 -
or clarification from the airport sponsor as needed. The FAA has stated43 that it must 

determine that the proposed measures are a sound economic investment for the Federal 

government based on emission reductions per dollar spent on the program. 

The FAA funding approval for a proposed airport low emission program is 

contingent upon a letter from the State air quality agency (or other governing air quality 

entity) to the FAA that the airport sponsor will receive emission credits for the proposed 

program in accordance with the conditions in this guidance (see State letter in Appendix 

G of FAA’s Voluntary Airport Low Emission Program Technical Report). In accordance 

with the Vision 100 Act, the FAA must receive this letter before AIP or PFC funding can 

be approved. The letter from the State air quality agency should indicate the State’s 

interest in participating, its preliminary acceptance of the airport proposal, and its 

assurance that the airport’s estimated emission reductions, if implemented as proposed, 

will receive an equal amount of AERCs. Without a State letter to this effect, the airport 

sponsor’s proposal is ineligible for FAA funding approval. 

5.3 Relationship of AERCs to the State Implementation Plan (SIP) 

The process of issuing AERCs begins with the State air quality agency review of 

the airport sponsor’s proposed project. If the project is acceptable, the State provides a 

written assurance to FAA that project emission reductions are eligible for AERCs, 

provided the project is funded and implemented. If the State air quality agency or EPA 

has any indication of the airport sponsor’s failure to appropriately implement an approved 

project, the agency should request a meeting with FAA and/or the airport sponsor to 

correct the situation. Failure to appropriately implement the project before AERCs are 

used could lead to the State air quality agency revoking the credits. 

Both the General Conformity44 and NSR45 regulations require that the reductions 

be enforceable by both the State and EPA. One method to ensure this enforceability is 

for the State to incorporate airport emission reduction measures into the SIP. If the State 

chooses to manage this program within the SIP, this action should take place before the 

AERCs are used in a general conformity evaluation or as a NSR offset. The State would 

not have to include the measures into the SIP in order to provide the assurance to FAA 

that the measures are eligible to create AERCs. Regardless of whether VALE emission 

reduction measures are incorporated into the SIP, they are enforceable through FAA 

grant assurances and airport program requirements to update and verify emission 

reduction estimates for their AERC application to the State air quality agency. 

If VALE measures are incorporated into the SIP, the State should ensure that the 

availability of the AERCs for the airport are not affected. The State should identify the 

relationship of the emission reduction measures (and AERCs) to the State’s 

demonstration of attainment. In most cases, it should be stated in the SIP that VALE 

surplus emission reductions and associated AERCs are being held for airport use in 

43 Voluntary Airport Low Emission Program Technical Report, Chapter 10, FAA, September 2004 44 40 C.F.R. 93.152 Emission offset 45 40 C.F.R. 51.165 

- 22 -
general conformity evaluations or as NSR offsets and are therefore not available for use 

as part of the attainment demonstration. In other words, the emission reductions set aside 

for the airport sponsor to meet general conformity and NSR requirements could not be 

double-counted by the State as part of its attainment demonstration. The unused AERCs 

may be available to assist the State in demonstrating compliance with its rate of progress 

milestones. 

VALE emission reduction measures also need to be managed within the context 

of existing SIP commitments that are made by the airport sponsor and its operators and 

tenants. Control measures already in the SIP through State and local agreements (e.g., 

Houston and the South Coast Air Quality Management District) are a factor in 

determining the surplus status of VALE emission reductions. Established SIP 

commitments need to be satisfied first before additional (surplus) VALE emission 

reduction measures could be creditable. It should be noted that airport sponsors are 

eligible for FAA funding to meet their CAA obligations under local agreements 

independent of the VALE program. 

5.4 FAA approval and program implementation 

The implementation phase of the program begins with FAA funding approval. 

The FAA may approve all, some, or none of the proposed airport low emission measures 

based on the availability of funding, project cost effectiveness, regional considerations, 

and other factors in the AIP and PFC decision process. The FAA may also stipulate 

modifications to proposed measures as needed. 

The FAA funding decision is one of several factors that could affect the airport 

sponsor’s proposal between the application phase and the implementation phase. Other 

factors that could affect the airport sponsor’s acquisition and deployment of equipment 

could be the availability of new or improved technology, changing usage estimates or 

costs, and the status of participating manufacturers or operators. 

It is therefore important for the airport sponsor to confirm, and as necessary to 

revise, its program and emission reduction estimates at the implementation phase based 

on updated information for the approved program. While the airport sponsor may 

determine when to send its updated report to the State air quality agency for AERCs, the 

timing of the airport sponsor’s submittal depends on the airport sponsor’s confidence in 

the implementation phase about the size, timing, and details of its funded project. The 

updated report should be presented to the State air quality agency in the same way as the 

initial application. If the airport sponsor submits the report after it has deployed major 

parts of its program, the airport sponsor should attempt, as practicable, to compare 

available information on actual operations with emission reduction estimates (based 

originally on certification, manufacturer, and/or model data). 

It is expected that State program review during the implementation phase will go 

quickly due to the previous State review during the application phase. Figure 2 shows the 

steps in the project implementation phase and crediting. Chapter 6 discusses how the 

- 23 -
State air quality agencies would issue AERCs to airports, when airports could use them, 

and how the AERCs would be updated and tracked. 

Figure 2 

Project Implementation Phase and Crediting 

Emission reduction update report to 

State AQ agency and EPA 

Airport project 

implementation 

Verification 

(AIP/PFC compliance, etc.) 

Airport credit use 

State AQ agency 

issues credits 

Airport credit 

statement 

Tracking process 

Documents 

Actions 

- 24 -
CHAPTER 6 

GRANTING AND USING AERCS 

As stated in the Vision 100 Act,46 AERCs are obtained and held by the airport 

sponsor and may only be used for any current or future general conformity or NSR 

permit requirements under the CAA. Consequently, credits that are in excess of what the 

airport sponsor needs for such purposes could not be traded, sold, or redirected and would 

simply represent an extra emissions benefit for the area. 

6.1 Granting of AERCs by the State air quality agency 

When the State air quality agency receives the airport sponsor’s updated emission 

reduction report during the project implementation phase, the State air quality agency 

should reevaluate the reasonableness of the emission reduction estimates and should issue 

an appropriate level of AERCs to the airport sponsor in a timely manner. The AERCs 

should be allocated by the State according to the same annual schedule and amount (tons 

per year) of emission reductions provided by the airport sponsor’s project. 

This process for issuing AERCs anticipates that the State air quality agency would 

provide an airport credit statement (ACS) to the airport sponsor (see Appendix B for a 

sample State credit statement to the airport). The ACS should list eligible credits by 

calendar year and pollutant. 

Depending upon the agency’s preference, the document (or certificate) could 

either be a paper document or electronic. A copy of this document would need to be 

made available to the public upon request. Multiple certificates could be applied to a 

single new project, and a single certificate could be applied to multiple projects that are 

proposed simultaneously. 

The AERC allocation process is intended to be simple with no disincentives to 

airport sponsors (discount ratios, penalties, administrative processing fees charged by air 

quality agencies, etc.). The basic recommendations for granting AERCs are as follows: 

• AERCs should be granted on a one-for-one annualized basis for each criteria 

pollutant/precursor (i.e., one ton per year of emission reductions for one ton per 

year of AERC). 

• AERCs and underlying airport emission reduction estimates should be carried and 

rounded to a tenth of a ton per year. 

• Annual AERCs for any current or future year could only be used once. 

46 49 U.S.C. § 47139(a)(2). 

- 25 -
• If applicable, AERC’s could be used or withdrawn for each year on a “first in, 

first out” basis. 

• The length of AERCs should be based on the useful life of VALE vehicles and 

equipment unless the airport sponsor agrees in advance to buy replacements that 

produce equal or lower emissions.47 

6.2 Life of the AERCs 

The value of an emission reduction measure may diminish over time if more 

stringent government regulations are adopted and these new requirements were not 

considered in the airport sponsor’s emission reduction calculations. Such events would 

decrease the surplus value of the early emission reductions used to obtain corresponding 

AERCs. 

Generally, AERCs should be available for the useful life48 of the equipment or up 

to 20 years. This lifetime provision or “sunset” is consistent with AIP and PFC terms, 

conditions, and assurances, which remain in full force and effect throughout the useful 

life of the facilities or equipment acquired for an airport development project over the 

same 20 year timeframe. With regard to VALE stationary source improvements at the 

airport with useful life beyond 20 years, stakeholders may agree to extend the life of 

associated AERCs to as long as 40 years. 

6.3 Airport sponsor use of AERCs 

The VALE program is one of many ways that airport sponsors can meet their air 

quality responsibilities. The benefit of early reductions and AERCs made possible 

through the program will vary from airport to airport. 

The Vision 100 Act requires that AERCs be kept by the airport sponsor and only 

used for meeting Federal general conformity requirements and NSR permit 

requirements.49 Consistent with AIP and PFC funding to individual airports and 

environmental compliance, the FAA considers each airport as an “independent facility” 

for purposes of receiving and using AERCs. 

AERCs would be assessed, earned, used, and retained on an individual yearly 

basis over the useful life of a VALE project. The approach to AERCs represents a year47 Airport sponsors and State air quality agencies may agree to extend AERCs based on Section 6.2 and 

“Special Conditions” in the VALE Technical Report, including the sponsor’s financial responsibility for 

low emission replacements. 48 FAA’s Voluntary Airport Low Emission Program Technical Report provides information on the useful 

life of airport equipment. 49 Airport AERCs are used for general conformity or NSR requirements. AERCs are not part of the EPA 

Voluntary Mobile Source Emission Reduction Program (VMEP) and thus are not subject to the three 

percent cap on voluntary measures set forth in the VMEP program. (Guidance on Incorporating Voluntary 

Mobile Source Reduction Programs in State Implementation Plans (SIPs), Memorandum from Richard D. 

Wilson Acting Administrator for Air and Radiation to EPA Regional Administrators, October 24, 1997) 

- 26 -
to-year credit system and not a multi-year “banking” system where all past emission 

savings add-up or accumulate. In effect, emission reductions achieved by the airport 

sponsor for each year translate into an equivalent number of AERCs on an annual basis 

for as many years as the project lasts. Airport sponsors could only apply AERCs to the 

year in which the associated emission reductions are projected to occur. 

The annualized framework for applying AERCs is reflected in the air quality 

regulatory process: 

• SIP budgets are generally developed on an annual basis making it is more 

realistic to apply AERCs to the year in which the emissions occur. 

• General conformity de minimis thresholds are annualized and expressed 

similarly in tons per year. This allows a consistent application of AERCs 

to de minimis levels in the context of project “design measures.” (See 

following section on General Conformity) 

• Airport sponsor updates to emission reduction estimates, emission factors, 

and assessment methodologies can focus on current and future years 

without concern to past years. 

• Implemented airport low emission projects should produce the same or 

similar emission reductions for many years into the future. 

Because AERCs would be acquired and used year-to-year, airport sponsors could 

not carry or accumulate past year emission reductions and AERCs forward to the current 

year or future years for use. In effect, these emission reduction benefits are no longer 

counted as credit toward general conformity and NSR permit requirements and become 

voluntary benefits to the environment that the State can claim towards meeting the SIP 

goals.50 

If AERCs from a control measure are used for a short-term project, unused and 

future AERCs from the measure are available for the airport sponsor’s use in other 

projects. 

The VALE program is not designed for emissions “trading.” Thus, this guidance 

document does not address the separate activity of trading, which is limited under the 

CAA and would conflict with restrictions in the AIP and PFC programs pertaining to 

revenue use and reimbursements. 

6.3.1 General Conformity 

Airport general conformity requirements are the major focus of the VALE 

program. Under General Conformity, airport sponsors would be allowed to apply 

AERCs on a 1:1 basis (i.e., one ton per year of AERCs for one ton per year of emission 

50 In the event that the State air quality agencies develop airport emission “budgets” as part of the SIP, the 

AERCs earned by the airport sponsor may be applied to meeting this budget. 

- 27 -
increases) as “design measures”51 against the CAA annual de minimis levels established 

for demonstrating conformity. When applied as design measures, the airport sponsor 

only needs to reduce the total direct and indirect emissions from the project emissions to 

below the de minimis emission levels. If an airport sponsor’s application of AERCs to an 

airport development project results in project emissions below de minimis levels, no 

general conformity determination would be required – as consistent with current general 

conformity rules. 

This approach to applying AERCs is intended to provide airport sponsors with 

greater incentive to employ early emission reductions. Design measures are considered 

related to future airport projects in time as if the emission reductions occurred as part of 

the future planning and design for the project. The early emission reductions would also 

considered related in space or proximity because the airport is considered a single facility 

for air quality management under this program. 

6.3.2 NSR 

For purposes of NSR permitting in nonattainment areas, AERCs could be used 

only as offsets. To be an NSR offsets, reductions are only creditable to the extent they 

are reduction in actual emissions. Actual emissions are those emissions that were 

previously emitted into the air. The EPA NSR program includes legally mandated offset 

ratios based on the severity of nonattainment areas. AERCs could be used for all NSR 

offset requirements including greater than 1:1 offset ratios. However, other adjustments 

are not recommended. For example, some States include a discounting feature in their 

NSR banking programs. Such features reduce the value of early emissions reductions 

when the AERCs are either generated or used. While the discounting mechanisms allow 

States to retire credits to increase their progress toward their SIP attainment goals, such 

conditions might suppress airport interest in early action. 

6.4 Updating, tracking and record keeping 

The airport sponsor should keep effective equipment records and label equipment 

that has been purchased through this program. Ongoing verification of equipment, 

operations, and the surplus nature of credited reductions would be needed, especially 

after the State issues the ACS and AERCs to the airport sponsor. 

The State air quality agency and the airport sponsor would both be responsible for 

maintaining copies of the ACS as well as tracking changes in Federal and State 

regulations that may affect the value of allocated AERCs over time. The airport sponsor 

may have incorporated planned regulatory changes into the future baseline and project 

calculations. If not, the airport sponsor would need to consider any difference in existing 

regulations when providing periodic updates to its emission reduction estimates, 

especially in the period preceding proposed use of AERCs. 

51 See EPA and FAA General Conformity Guidance for Airports, Q&A’s, September 25, 2002. Question 

#38 clarifies the distinctions between “design measures”, “mitigation measures”, and “offsets.” 

- 28 -
The airport sponsor would be responsible for updating its underlying emission 

reduction estimates in two cases: 1) when changes warrant corrections to the estimates; 

and 2) when the airport sponsor declares that it intends to use its AERCs. In both cases, 

the airport sponsor should provide its updated report, and the effects on the ACS and 

number of AERCs, to the State air quality agency, the EPA, and the FAA. Updated 

calculations would be only required for current and future project years. 

In addition, the airport sponsor should keep track of operational and facility 

changes over time that could affect the emission reduction estimates. Any new 

information that may change the amount of allocated AERCs (higher or lower) would 

need to be presented to the State air quality agency prior to AERC use in order to verify 

the continued validity of the AERCs and the emission reduction estimates upon which 

they are based. 

State air quality agencies and airport sponsors would not have to notify the public 

when AERCs are granted through the ACS. However, when an airport sponsor decides 

to use its AERCs to meet Federal general conformity requirements or NSR permit 

requirements, the airport sponsor would need to notify the public (e.g. notice in a local 

paper) and in writing to the State air quality agency and the EPA Regional Office that 

they are intending to do so. Following the airport use of AERCs, the State air quality 

agency would need to revise the airport’s AERC balance accordingly and send the airport 

sponsor a new credit statement on the airport’s remaining AERCs. 

- 29 -
- 30 -
APPENDIX A 

Section 158. Emission Credits for Air Quality Projects 

H.R.2115 

One Hundred Eighth Congress 

of the 

United States of America 

AT THE FIRST SESSION 

Begun and held at the City of Washington on Tuesday, 

the seventh day of January, two thousand and three 

An Act 

To amend title 49, United States Code, to reauthorize programs for the Federal Aviation 

Administration, and for other purposes. 

Be it enacted by the Senate and House of Representatives of the United States of America 

in Congress assembled, 

SECTION 1. SHORT TITLE; TABLE OF CONTENTS.

(a) SHORT TITLE- This Act may be cited as the `Vision 100--Century of 

Aviation Reauthorization Act'. 

(b) TABLE OF CONTENTS- The table of contents for this Act is as follows: 

Sec. 1. Short title; table of contents. 

Sec. 2. Amendments to title 49, United States Code. 

Sec. 3. Applicability. 

Sec. 4. Findings. 

TITLE I--AIRPORT AND AIRWAY IMPROVEMENTS 

Subtitle A--Funding of FAA Programs 

Sec. 101. Airport planning and development and noise compatibility 

planning and programs. 

Sec. 102. Air navigation facilities and equipment. 

Sec. 103. Federal Aviation Administration operations. 

Sec. 104. Funding for aviation programs. 

Sec. 105. Agreements for operation of airport facilities. 

Sec. 106. Insurance. 

Subtitle B--Passenger Facility Fees 

Sec. 121. Low-emission airport vehicles and ground support equipment. 

Sec. 122. Use of fees to pay debt service. 

Sec. 123. Streamlining of the passenger facility fee program. 

Sec. 124. Financial management of passenger facility fees. 

Subtitle C--AIP Modifications 

Sec. 141. Airfield pavement. 

Sec. 142. Replacement of baggage conveyor systems. 

Sec. 143. Authority to use certain funds for airport security programs and 

activities. 

- 31 -
Sec. 144. Grant assurances. 

Sec. 145. Clarification of allowable project costs. 

Sec. 146. Apportionments to primary airports. 

Sec. 147. Cargo airports. 

Sec. 148. Considerations in making discretionary grants. 

Sec. 149. Flexible funding for nonprimary airport apportionments. 

Sec. 150. Use of apportioned amounts. 

Sec. 151. Increase in apportionment for, and flexibility of, noise 

compatibility planning programs. 

Sec. 152. Pilot program for purchase of airport development rights. 

Sec. 153. Military airport program. 

Sec. 154. Airport safety data collection. 

Sec. 155. Airport privatization pilot program. 

Sec. 156. Innovative financing techniques. 

Sec. 157. Airport security program. 

Sec. 158. Emission credits for air quality projects. 

Sec. 159. Low-emission airport vehicles and infrastructure. 

Sec. 160. Compatible land use planning and projects by State and local 

governments. 

Sec. 161. Temporary increase in Government share of certain AIP project 

costs. 

Sec. 162. Share of airport project costs. 

Sec. 163. Federal share for private ownership of airports. 

Sec. 164. Disposition of land acquired for noise compatibility purposes. 

Sec. 165. Hangar construction grant assurance. 

Sec. 166. Terminal development costs. 

- 32 -
SEC. 158. EMISSION CREDITS FOR AIR QUALITY PROJECTS. 

(a) EMISSIONS CREDIT- Subchapter I of chapter 471 is further amended by 

adding at the end the following: 

“§ 47139. Emission credits for air quality projects 

“(a) IN GENERAL- The Administrator of the Environmental Protection Agency, 

in consultation with the Secretary of Transportation, shall issue guidance on how 

to ensure that airport sponsors receive appropriate emission reduction credits for 

carrying out projects described in sections 40117(a)(3)(G), 47102(3)(F), 

47102(3)(K), and 47102(3)(L). Such guidance shall include, at a minimum, the 

following conditions: 

“(1) The provision of credits is consistent with the Clean Air Act (42 

U.S.C. 7402 et seq.). 

“(2) Credits generated by the emissions reductions are kept by the airport 

sponsor and may only be used for purposes of any current or future 

general conformity determination under the Clean Air Act or as offsets 

under the Environmental Protection Agency's new source review program 

for projects on the airport or associated with the airport. 

“(3) Credits are calculated and provided to airports on a consistent basis 

nationwide. 

“(4) Credits are provided to airport sponsors in a timely manner. 

“(5) The establishment of a method to assure the Secretary that, for any 

specific airport project for which funding is being requested, the 

appropriate credits will be granted. 

“(b) ASSURANCE OF RECEIPT OF CREDITS- As a condition for making a 

grant for a project described in section 47102(3)(F), 47102(3)(K), 47102(3)(L), or 

47140 or as a condition for granting approval to collect or use a passenger facility 

fee for a project described in section 40117(a)(3)(G), 47103(3)(F), 47102(3)(K), 

47102(3)(L), or 47140, the Secretary must receive assurance from the State in 

which the project is located, or from the Administrator of the Environmental 

Protection Agency where there is a Federal implementation plan, that the airport 

sponsor will receive appropriate emission credits in accordance with the 

conditions of this section. 

“(c) PREVIOUSLY APPROVED PROJECTS- The Administrator of the 

Environmental Protection Agency, in consultation with the Secretary, shall 

determine how to provide appropriate emissions credits to airport projects 

previously approved under section 47136 consistent with the guidance and 

conditions specified in subsection (a). 

“(d) STATE AUTHORITY UNDER CAA- Nothing in this section shall be 

construed as overriding existing State law or regulation pursuant to section 116 of 

the Clean Air Act (42 U.S.C. 7416).”. 

(b) CONFORMING AMENDMENT- The analysis for chapter 471 is further 

amended by inserting after the item relating to section 47138 the following: 

“47139. Emission credits for air quality projects.”. 

- 33 -
- 34 -
APPENDIX B 

Sample State Air Quality Agency Credit Statement (ACS) to the Airport Sponsor 

[Date] 

Airport Manager (Name & Title) 

Airport Name 

Address 

City, ST, Zip 

To _____________ [Airport Manager Name] 

Based on the updated report submitted by _____________ [airport sponsor’s name] on 

_____________ [date] for the VALE program, the ____________________________ 

[State air quality agency] has determined that the airport sponsor’s estimates for early 

emissions reductions are reasonable and accurate. In accordance with these projections, 

the following airport emission reduction credits (AERCs) are hereby granted to the 

airport sponsor: 

Annual AERC Allocation (tons/year) 

Calendar 

Year 

NOx VOCs CO PM10 SO2 Other 

1 2006 

2 2007 

3 2008 

4 2009 

5 2010 

6 2011 

7 2012 

8 2013 

9 2014 

10 2015 

11 2016 

12 2017 

13 2018 

14 2019 

15 2020 

16 2021 

17 2022 

18 2023 

19 2024 

20 2025 

Based on information provided by _________________ [airport sponsor name], we have 

determined that all [nearly all, a portion, etc.] of the estimated emission reductions meet 

- 35 -
AERC requirements in accordance with U.S. Environmental Protection Agency (EPA) 

“Guidance on Airport Emission Reduction Credits for Early Measures through Voluntary 

Airport Low Emission Programs.” Annual AERCs have been allocated on a 1:1 basis 

with annual surplus emission reductions (tons/year). 

[optional paragraph if State air quality agency issues fewer AERCs than requested) The 

reason for fewer AERCs allocated than requested for the year(s) of _________ or for the 

pollutant(s) ________________ is as follows: 

The airport sponsor may use the AERCs granted in this Statement to meet future general 

conformity evaluation and NSR permit requirements for the year in which the AERCs are 

generated and listed above. In accordance with EPA guidance, the airport sponsor should 

notify the State air quality agency, the EPA Regional Office, and the public of its 

intention to use AERCs. At time of use, the airport sponsor must demonstrate to the State 

air quality agency that AERC-based emission reductions continue to represent real and 

surplus reductions. 

If you have any questions, please contact __________________ [contact name at State 

air quality agency] at ___________ [phone] or ______________ [email address]. 

Sincerely, 

Director 

State Air Quality Agency 

cc: EPA Regional Office, FAA regional offices 

- 36 -