Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

* NOTE: Ozone NAAQS implementation requirements are currently being assessed as part of the Implementation of the 2008 National Ambient Air Quality Standards for Ozone: State Implementation Plan Requirements; Proposed Rule (78 FR 34178, June 6, 2013) (Hereinafter, “Proposed Ozone Implementation Rule”). Accordingly, the guidance provided in this document addresses the options that were addressed in the Proposed Ozone Implementation Rule, which may or may not be adopted in the final rule. The guidance provided in this draft document is not final, and to the extent that the Final Ozone Implementation Rule takes a different approach than contained in this guidance , the Final Rule will dictate what is required for the necessary emissions inventories. Once the Final Ozone Implementation Rule is published, EPA will revise this guidance to reflect the regulations and requirements adopted in the final rule.

In addition , PM NAAQS implementation requirements are currently undergoing review as part of the planned proposed PM 2.5 Implementation Rule, so those requirements are not summarized in this draft guidance. Instead, this draft includes the use of “[PM Implementation P laceholder]” text w h ere necessary. Once that rule is finalized, this guidance will be updated and the [PM Implementation Placeholder] text will be replaced with the PM

- specific guidance associated with that rule. 

# DRAFT



# Emissions Inventory Guidance for Implementation of Ozone [ and Particulate Matter ] * 

# National Ambient Air Quality Standards (NAAQS) and Regional Haze RegulationsEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

i 

## Table of Contents
List of Tables

................................ ................................ ................................ ................................ ................. v Acronyms and Abbreviations Used in this Guidance

................................ ................................ ................... vi

1 Introduction

................................ ................................ ................................ ................................ .......... 1

1.1 Purpose

................................ ................................ ................................ ................................ ......... 1

1.2 Other Inventory Guidance and Resources

................................ ................................ .................... 2

1.3 Summary of Relevant Statutory Provisions

................................ ................................ .................. 4

1.4 Summary of Guidance Contents

................................ ................................ ................................ ... 7

2 SIP Inventory Overview

................................ ................................ ................................ ......................... 8

2.1 Recommended Steps for Building the Inventory Parts of a SIP

................................ .................... 8

2.2 Discuss the Inventory Approval Process with EPA

................................ ................................ ...... 10

2.3 Planning and Modeling Inventory Components

................................ ................................ ......... 11

2.3.1 Ozone SIP Inventory Components

................................ ................................ ...................... 11

2.3.2 Annual and 24

- Hour PM 2.5 SIP Inventory Components

................................ ...................... 12

2.3.3 Regional Haze SIP Inventory Components

................................ ................................ .......... 12

2.4 Other Relevant Federal Emissions Reporting Requirements

................................ ...................... 13

2.5 Emissions Inventory Definitions

................................ ................................ ................................ .. 14

2.5.1 Source Category/Data Category

................................ ................................ ......................... 15

2.5.2 Types of Emissions: Annual, Seasonal, Actual, Potential, and Allowable

........................... 15

2.5.3 Duration and Timing of Emissions

................................ ................................ ...................... 17

2.5.4 Data Elements

................................ ................................ ................................ ..................... 17

2.5.5 Throughput and Activity

................................ ................................ ................................ ..... 17

2.5.6 Emission Factors

................................ ................................ ................................ .................. 18

2.5.7 Emis sions Reporting Data Elements

................................ ................................ ................... 18

2.5.8 Point Sources

................................ ................................ ................................ ...................... 20

2.5.9 Nonpoint Sources

................................ ................................ ................................ ................ 21

2.5.10 On

- road Mobile Sources

................................ ................................ ................................ ..... 21

2. 5.11 Nonroad Mobile Sources

................................ ................................ ................................ .... 22

2.5.12 Events

................................ ................................ ................................ ................................ .. 22

2.5.13 Biogenic Sources

................................ ................................ ................................ ................. 22

2.5.14 Inventory Codes

................................ ................................ ................................ .................. 23Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

ii 2.5.15 Poi nt source Facility Details

................................ ................................ ................................ 24

2.5.16 Alternative IDs

................................ ................................ ................................ ..................... 26

2.5.17 Location Definitions

................................ ................................ ................................ ............ 27

2.5.18 Control Data Elements

................................ ................................ ................................ ........ 27

2.5. 19 EIS Sectors, Tiers, and Facility Type

................................ ................................ .................... 28

2.5.20 Other Terms

................................ ................................ ................................ ........................ 29

3 SIP Inventory Requirements and Recommendations

................................ ................................ ......... 30

3.1 Inventory Component Timing

................................ ................................ ................................ ..... 30

3. 2 Inventory Preparation Plan

................................ ................................ ................................ ......... 31

3.3 Base Year Inventory

................................ ................................ ................................ .................... 33

3.4 Rate of Progress and Reasonable Further Progress Baseline NAA Inventory

............................. 34

3.4.1 ROP/RFP Requirements and Timing

................................ ................................ .................... 34

3.4.2 ROP/RFP Inventory Guidance

................................ ................................ ............................. 35

3.5 Periodic Inventory

................................ ................................ ................................ ....................... 36

3.5.1 Ozone Periodic Inventory

................................ ................................ ................................ .... 36

3.5.2 Regional Haze Current Year Inventory

................................ ................................ ................ 3 8

3.6 Emissions Statement Requirement for SIPs

................................ ................................ ................ 39

3.7 Maintenance Inventories

................................ ................................ ................................ ............ 39

3.8 Projected Inventories

................................ ................................ ................................ .................. 40

3.8.1 Attainment Year Projected Inventories

................................ ................................ .............. 40

3.8.2 Rate of Progress and Reasonable Further Progress Emissions Reductions

........................ 41

3.9 Public Hearings

................................ ................................ ................................ ............................ 42

3.10 Submit Inventory Parts of SIP to the EPA

................................ ................................ ................... 43

4 Developing Current Emissions inventories

................................ ................................ ......................... 47

4.1 Inventory Years

................................ ................................ ................................ ........................... 47

4.2 Pollutants and Pollutant Precursors to Include in Inventories

................................ ................... 49

4.2.1 Condensable PM emissions

................................ ................................ ................................ 49

4.2.2 Regulatory Definition of VOC

................................ ................................ .............................. 49

4.2.3 Treatment of Methane

................................ ................................ ................................ ....... 50

4.3 Identification of Priority Sources

................................ ................................ ................................ 51

4.4 Spatial Extent

................................ ................................ ................................ .............................. 53

4.4.1 Nonattainment Areas with Partial Counties

................................ ................................ ....... 53Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

iii 4.4.2 Point Source Locations Needed for Modeling of Traditional Nonpoint Sources

................ 55

4.4.3 Shapefile

- based Inventorie s

................................ ................................ ................................ 55

4.4.4 Link

- based On

- road Mobile Emissions and Travel Demand Models

................................ .. 56

4.5 Temporal Basis

................................ ................................ ................................ ............................ 56

4.6 Emission F actors for SIP Emissions Inventories

................................ ................................ .......... 57

4.7 Inventory Data Codes

................................ ................................ ................................ .................. 59

4.7.1 Codes to Use for Nonattainment Area Inventories

................................ ............................ 59

4.7.2 How to Request New Codes or Code Retirements

................................ ............................. 59

4.8 Estimation of Base Year Emissions

................................ ................................ .............................. 60

4.8.1 Stationary Point

................................ ................................ ................................ .................. 60

4.8.2 Stationary Nonpoint

................................ ................................ ................................ ............ 64

4.8.3 On

- road Mobile

................................ ................................ ................................ ................... 68

4.8.4 Nonroa d Mobile Equipment

................................ ................................ ............................... 69

4.8.5 Other Nonroad Mobile

................................ ................................ ................................ ........ 70

4.8.6 Biogenic and Geogenic Sources

................................ ................................ .......................... 78

4.8.7 Wildland Fires

................................ ................................ ................................ ..................... 81

4.9 Quality Assurance

................................ ................................ ................................ ....................... 82

4.9.1 QA Reference Materials and Planning

................................ ................................ ................ 83

4.9.2 Types of Problems in Emissions Inventories

................................ ................................ ....... 83

4.9.3 Checks Available Through the EPA’s Emissions Inventory System

................................ ..... 84

4.9.4 Inventory Comparisons

................................ ................................ ................................ ....... 85

4.9.5 Checking Data Codes

................................ ................................ ................................ ........... 86

4.9.6 Point Versus Nonpoint and Reconciliation

................................ ................................ ......... 86

4.9.7 Ranking Techniques

................................ ................................ ................................ ............ 87

4.9.8 Ou tlier Analyses

................................ ................................ ................................ .................. 88

4.9.9 Using Maps to QA Nonpoint Emissions

................................ ................................ .............. 89

4.9.10 Expected Pollutants

................................ ................................ ................................ ............ 89

4.9.11 Facility and Release Point Locations

................................ ................................ ................... 90

4.9.12 Release Point Parameters

................................ ................................ ................................ ... 91

4.9.13 Biogenic QA/QC

................................ ................................ ................................ ................... 92

4.9.14 Timing of QA and Follow

- up

................................ ................................ ............................... 92

5 Developing Projected Emissions Inventories

................................ ................................ ...................... 94Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

iv 5.1 Projected Emissions Overview

................................ ................................ ................................ .... 94

5.2 Identify and Prioritize Key Sectors and Regions for Projections

................................ ................. 95

5.3 Collect Available Data and Models for Each Sector Needing Projections

................................ .. 96

5.3.1 Stationary Sources

................................ ................................ ................................ .............. 96

5.3.2 On

- Road Mobile Sources

................................ ................................ ................................ .... 99

5.3.3 Nonroad Mobile Equipment

................................ ................................ ............................... 99

5.3.4 Other Nonroad Mobile Sources

................................ ................................ ........................ 100

5.3.5 Other Projection Resources

................................ ................................ .............................. 101

5.4 Evaluate and Refine Data for Projections in Inventory Region

................................ ................. 104

5.5 QA for Projected Inventories

................................ ................................ ................................ .... 104

6 References

................................ ................................ ................................ ................................ ........ 106Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

v 

## List of Tables
Table 1: List of estimation resources for emissions inventories

................................ ................................ ... 2 Table 2: Steps for building the inventory parts of a SIP

................................ ................................ ................ 9 Table 3: Tangible products for possible inclusion in inventory efforts

................................ ....................... 10 Table 4: Ozone SIP emissions inventory components

................................ ................................ ................ 11 Table 5: PM 2.5 SIP emissions inventory components

................................ ................................ .................. 12 Table 6: Regional Haze SIP emissions inventory components

................................ ................................ .... 13 Table 7: Point source reporting thresholds (potential to emit) for criteria pollutants in the Air Emissions Reporting Rule

................................ ................................ ................................ .............................. 21 Table 8: Timing of emissions inventory components

................................ ................................ ................. 30 Table 9: Checklist of elements to consider for includi ng in Inventory Preparation Plans

.......................... 32 Table 10: Conditions for AERR submittal to meet ozone periodic inventory requirement

........................ 37 Table 11: Conditions for AERR submittal to meet regional haze periodic inventory requirement

............ 38 Table 12: Suggested Elements of an Emissions inventory SIP

................................ ................................ .... 43 Table 13: Summaries to include in the background

................................ ................................ ................... 45 Table 14: Summaries to include in the point sources se ction

................................ ................................ .... 46 Table 15: Summaries to include in the nonpoint and mobile sources sections

................................ ......... 46 Table 16: Source types expected to include condensable PM +

................................ ................................ .. 49 Table 17: Hierarchy of emission factors for use in point source emissions inventories

............................ 58 Table 18: List of nonpoint categories, pollutants, and available approaches and tools

............................. 65 Table 19: Aircraft SCCs and Data Categories in EPA Estimates

................................ ................................ ... 71 Table 20: Commercial marine SCCs and emission types in EPA emissions

................................ ................. 74 Table 21: Commercial marine vessel recent regulations and impacted pollutants

................................ ... 74 Table 22: : Current EPA methods for commercial marine vessel emissions.

................................ .............. 75 Table 23: Locomotive SCCs

................................ ................................ ................................ ......................... 77Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

vi 

## Acronyms and Abbreviations Used in this Guidance
AEO Annual Energy Outlook AERR Air Emissions Reporting Rule APU Auxiliary power unit BEIS Biogenic Emission s Inventory System BELD3 Biogenic Emissions Land U se Database, version 3 AT Air Taxis C1 Category 1 (marine vessel) C2 Category 2 (marine vessel) C3 Category 3 (marine vessel) CAA Clea n Air Act CAMD Clean Air Markets Division CAP Criteria air pollutant CAS Chemical Abstracts Service CEM S Continuous Emissions Monitoring System(s) CMV Commercial marine vessel CNG Compressed natural gas CO Carbon monoxide CO2 Carbon dioxide DARS Data Attri bute Rating System DOE Department of Energy ECA

- IMO Emissions Control Area

- International Maritime Organization EDMS Emissions and Dispersion Modeling System EGU Electric Generating Unit EIA Energy Information Administration EIIP Emissions inventory Improve ment Program EIS Emission s Inventory System EMCH Emissions Modeling Clearinghouse EPA Environmental Projection Agency EPM M Electric Power Market Model ERTAC Eastern Regional Technical Advisory Committee FAA Federal Aviation Administration FHWA Federal Highway Administration FIPS Federal Information Processing Standards FRS Federal Registry Service GA General aviation GHG Greenhouse gas GIS Geographic Information Systems GloBEIS Global Biosphere Emissions and Interactions System GSE Ground support equipment HAP Hazardous air pollutantEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

vii Hg Mercury HCl Hydrochloric acid IPM Integrated Planning Model IPP Inventory Preparation Plan LPG Liquified petroleum gas LTO Landing and takeoff MARKAL M ark et A ll ocation (model) MEGAN Model of Emissions of Gases and A er o sols from Nature MIMS Multimedia Integrated Modeling System MOVES Motor Vehicle Emissions System NAAQS National Ambient Air Quality Standards NAA Nonattainment area NAICS North American Industry Classification System NATA National Air Toxics Assessment NEEDS National Electric Energy Data NEI National Emissions Inventory NEMS National Energy Modeling System NESHAP National Emission Standard for Hazardous Air Pollutants NH 3 Ammonia NLDN National Lightning Dete ction Network NMIM National Mobile Inventory Mo del NONROAD Nonroad emissions model NMHC Non

- methane hydrocarbon NO X Nitrogen Oxides O 3 Ozone OAP Office of Atmospheric Programs OAQPS Office of Air Quality Planning and Standards OAR Office of Air and Radiation OECA Office of Enforcement and Compliance Assurance ORIS Office of Regulatory Information Systems OTAQ Office of Transportation Air Quality PM Particulate m atter PM 2.5 Particulate matter with diameter 2.5 microns and less PM 10 Particulate m atter with diameter 10 microns and less QAPP Quality Assur ance Project Plan RICE Reciprocating Internal Combustion Engines RFP Reasonable Further Progress ROP Rate of Progress SCC Source classification code SIP State implementation p lan SMOKE Sparse Matrix Operator Kernel Emissions SO 2 Sulfur DioxideEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

viii SSM Startup, Shutdown, and Malfunction STEEM Ship Traffic, Energy and Environmental Model TAF Terminal Area Forecast TCA 1,1,1

- trichloroethane TDM Travel demand model TIP Tribal Implementation Plan TOG Total organic gases TRI Toxics Release Inventory U

. S

. United States USDA U.S. Department of Agriculture VMT Vehicle miles traveled WFU Wildland fire use WLF Wildland fire WRF Weather Research and Forecasting VOC Volatile organic compoundsEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

1 

## 1 Introduction

1.1 Purpose This document provides guidance on how to develo p emissions inventories to meet state implementation p lan (SIP) requirements for complying with the 8

- hour ozone national ambient air quality standard (NAAQS) 1

, [ the daily and annual fine particulate matter (PM 2.5 ) NAAQS ] 2 , and the regional haze regulations

. It is intended for use by the United States (U

. S

. ) Environmental Protection Agency (EPA) regional office s; state, local and t ribal air quality management authorities; and the general public

. Th is guidance is de signed to implement national policy on these emissions inventories as embodied in the Clean Air Act (CAA) , the Proposed Ozone SIP Requirements Rule (also called the Proposed Ozone Implementation Rule) 3 , the PM 2.5 4 Implementation Rule 5 , and the Regional Haz e Rule.
This document does not substitute for provisions or r egulations of the CAA enumerated above, nor is it a regulation itself

. As the term “guidance ” suggests, it provides recommendations on how to implement the inventory requirements

. Thus, it does n ot impose binding, enforceable requirements on any party, nor does it assure that the EPA will approve all instances of its application, as the guidance may not apply to a particular situation based upon the circumstances

.
The EPA and s tate , local, and t r ibal decision makers retain the discretion to adopt approaches on a case

by

- case basis that differ from this guidance where appropriate

. Final decisions by the EPA regarding a particular SIP demonstration will only be made based on the statute and regulations, and will only be made following a final submission and after notice and opportunity for public review and comment

. Interested parties are free to raise questions and objections about the appropriateness of the application of this guidance to a particular situ ation; the EPA will, and state, local, and tribal air agencies should, consider whether or not the recommendations in this guidance are appropriate in that situation.

1 As noted on the title page, Ozone NAAQS implementation requirements are currently being assessed as part of the Implementation of the 2008 National Ambient Air Quality Standards for Ozone: State Impl ementation Plan Requirements; Proposed Rule (78 FR 34178, June 6, 2013) (Hereinafter, “Proposed Ozone Implementation Rule”). Accordingly, the guidance provided in this document addresses the options that were addressed in the Proposed Ozone Implementation Rule, which may or may not be adopted in the final rule. The guidance provided in this draft document is not final, and to the extent th at the Final Ozone Implementation Rule takes a different approach than contained in this guidance, the Final Rule will dictate what is required for the necessary emissions inventories. Once the Final Ozone Implementation Rule is published, EPA will revise this guidance to reflect the regulations and requirements adopted in the final rule. 2 As noted on the title page, PM NAAQS implementation requirements are currently undergoing review as part of the planned prop o sed PM 2.5 Implementation Rule , so those requirements are not summarized in this draft guidance. Instead, this draft includes the use of “[PM Implementation Pla ceholder]” text where necessary. Once that rule is finalized, this guidance will be updated and the [PM Implementation Placeholder] text will be replaced with the PM

- specific guidance associated with that rule. 3 Implementation of the 2008 National Ambient Air Quality Standards for Ozone: State Implementation Plan Requirements; Proposed Rule (78 FR 34178, June 6, 2013)
4 PM 2.5 is particulate matter with diameter 2.5 microns and less
5 Fine Particulate Matter National Ambient Air Quality Standards: State Imp lementation Plan Requirements, proposed rule anticipated in mid 2014.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

2 Through the prov isions of the T ribal Authority Rule, t ribes are not required to develop emissions inventories

. If tribe s choose to develop an emissions inventory that may become part of a SIP or Tribal Implementation Plan (TIP) inventory covered by this guidance, the trib e s are encouraged to follow the provisions of this guidance

. Notwithstanding the possible development by local and tribal air agencies, inventories prepared for NAAQS implementation will be called SIPs in the remainder of this document.



### 1.2 Other Inventory G ui dance and R esources This document is a guide for state, local, and tribal air agencies (called “air agencies” in this guidance) for preparing and submitting their emissions inventories for the 8

- hour ozone NAAQS and [PM Implementation Placeholder] , and for the regional haze program

. It is not a procedures document that comprehensively cover s the methods for compiling and documenting emissions inventories

. Fu rthermore, th e predecessors to th is guidance have historically relied on separate guidance documents
to add information for various specific purposes

. In Section 2.3 , we list the various inventory components needed for 8

- hour ozone, PM 2.5 , and r egional haze implementation and identify the associated sections of this guidance and other relevant guidance materi als.
In addition to this guidance, the “ Guidance on the Use of Models and Other Analyses for Demonstrating Attainment for Air Quality Goals for Ozone, PM 2.5 , and Regional Haze ” ( http://www.epa.gov/ttn/ scram/guidance_sip.htm ) , or “Modeling Guidance”, covers the creation of emissions inventories for use in air quality modeling

. These m odeling inventories differ from the inventories covered in this document in that they usually have a larger spatial extent (i.e., a multi

- state area as opposed to just the nonattainment area) and require extra processing steps to obtain the spatial and te mporal resolution of the air quality model input species

. To the extent the Modeling Guidance covers future

- year emissions, efforts have been made to harmonize the future

- year guidance in that Guidance with the information included in Section 5 of this document.

A number of inventory development resources are available for use by air agencies for estimating base
year emissions inventories

. Table 1 provides these references and a brief description of how they can be used

. More information on how these resources can be applied is provided in Section s 4 and 5

.

Table 1 : List of estimation resources for emissions inv entories
Resource and website Description
National Emissions Inventory (NEI) ( www.epa.gov/ttn/chief/ eiinformation.html ) Summaries of the latest NEI data and documentation are available from links provided at this website

. More detailed data are available to air agencies from the Emission s Inventory System (EIS)

.

Emission Factors used for the National Emissions Inventory (NEI) λ ( ww w.epa.gov/ttn/chief/ eiinformation.html ) The National Emissions Inventory (NEI) program provides emissions estimation tools (that include emission factors) and point

- source emission factors based on EPA rule development efforts. In many cases, these factor s are more recent than those in WebFire and AP

- 42, and agencies are encouraged to rely on these where available. Emissions Inventory System The EIS allows for summaries and extr action of detailed dataEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

3 Resource and website Description ( www.epa.gov/ttn/chief/eis/ ) for use by air agencies . The EIS allows both state

- submitted as well as the composite EPA

- state data used for the NEI to be queried and downloaded

. Training on reports is also available, and Appendix A provides an EIS quick reference for county and facility reports.

Local

- scale emissions inventory development ( www.epa.gov/ttn/chief/ local_scale/ ) In 2010, the EPA completed a project to assess the building of multi

- pollutant inventories at the scale of nonattainment

areas. A project description and the final r eport are available; the latter documents the recommended actions for state and local agencies that want to develop local

- scale emissions inventories , including SIP planning inventories

. Electric Generating Unit emissions data from Continuous Emissions Mo nitor ing Systems (CEMS ) ∆ ( ampd.epa.gov/ampd ) Carbon dioxide ( CO 2 )
, nitrogen oxides ( NO X )
, sulfur dioxide ( SO 2 ) , and heat input data from Electric Generating Units ( EGUs ) collected by the EPA

. Heat input data can be used to estimate hourly emissions of other pollutants using emission factors.

Emissions I nventory Improvement Program (EIIP) Documentation, Volumes 1

- 9. ( www.epa.gov/ttn/ chief/eiip/techreport/ ) Emissions estimation procedures for point, area (nonpoint) and mobile sources. While much of the information included in these reports is still relevant, t he EIIP documentation for point and nonpoint sources has some outdated parts , and the sections below indicate some of those limitations and alternative resources. The EIIP documentation for mobile sources (volume 4) is out of date because it refers to previous versions of EPA emissions models. Use more current resources, listed below for mobile sources an d fires. While EIIP is also out of date for biogenic sources, these sources are relevant only for modeling inventories and not for the inventories covered by this guidance.

Emission Factors

– WebFire and AP

- 42 ( www.epa.gov/ttn/chief/ efpac/index.html ) Emission factors are used to estimate emissions, generally by multiplying by some activity value for that emissions activity , where no better method of emissions quantification or estimation is avai lable

. AP

- 42 is not an appropriate source of emission factors for mobile sources other than road dust. General Principles for the 5

- Year Regional Haze Progress Reports for the Initial Regional Haze State Implementation Plans ( www.4cleanair.org/Documents/ haze_5year_4

- 10

- 13.pdf ) This document has been developed by the EPA for the EPA regional offices and states in preparing and reviewing the 5

- year progress reports for the initial regional haze SIPs. This document summarizes and clarifies the requirements for the first 5

- year reports, including emissions inventory aspects.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

4 Resource and website Description Motor Vehicle Emissions System (MOVES) ( www.epa.gov/otaq/ models/moves/ ) The model, technical documentation, and guidance on the use and application of the MOVES model for on

- road mobile

sources. Nonroad Emissions model (NONROAD) ‡ ( www.epa.gov/otaq/nonrdmdl.htm ) The model and technical documentation on the use of the NONROAD model for nonroad equipment

. National Mobile Inventory Model (NMIM) ( www.epa.gov/otaq/ nmim.htm ) NMIM is also used in conjunction with NONROAD. It runs NONROAD but includes some additional features, such as the computation of ammonia (NH 3 ) emissions.

Mobile sources Policy and Guidance ( www.epa.gov/otaq/ stateresources/policy/ ) Webpage that provides state and local agencies with direction on how to implement strategies fo r controlling emissions from mobile sources

. Includes links to guidance documents that describe process for securing SIP air quality credits for voluntary and in novative emission reduction programs. Transportation Conformity ( www.epa.gov/otaq/ stateresources/transconf/ ) General information, policy and technical guidance about transportation conformity

.
λ F rom this main web page, obtain factors using the link to the latest available NEI or NEI Plan

. ∆ Select “Data Sets and Published Reports”

. ‡ The NONROAD model is expected to be superseded by the MOVES model once nonroad sources are included in MOVES.
In addition to base year emissions, emissions projections are needed for a variety of reasons, including redesignation maintenance plans, the attainment projected inventory for a nonattainment area (NAA)
, and air quality modeling for a tt ainment plans

. In Section 5 , this guidance provides information on methods for emissions projections

. The EPA provides emissions projections data and documentation as part of its modeling platforms, which are available at the Emissions Modeling Clearinghouse ( http://www.epa.gov/ttn/chief/emch/index.html )

. On

- road mobile source projections are covered in the

on

- road mobile regulatory documentation associated with MOVES . Nonroad mobile projections are included as part of the NMIM and the NONROAD model documentation for nonroad equipment and as part of this do cumentation in the n onroad mobile sources part of Section 5

. 

### 1.3 Summary of Relevant Statutory Provisions
N umerous sections of the CAA apply to the implementation of e missions inventory requirements

. This section provides a brief synopsis of some of those sections that may be relevant for reference in later sections of this guidance

. All of the sections below are a part of CAA Title I

– Programs and Activities.

 Section 110(a) describes the basic requirements for SIPs , which provide for implementation, maintenance, and enforcement of the NAAQS

.
o Section 110(a)(1) specifies parameters for infrastructure SIPs

o Section 110(a)(2) specifies a “notice and public hearing” process is needed

o Section 110(a)(2)(F) specifies that infrastructure SIPs shall require, as may be prescribed by t he EPA Administrator , “periodic reports on the nature and GeneralEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

5 amounts of emissions and emissions

- related data” from stationary sources

.
o Section 110(a)(2)(K) requires infrastructure SIPs to include air quality modeling as determined necessary by the Administrator and allows the EPA
to require the submission upon request of data related to that air quality modeling.

o Section 110(a)(2)(J) addresses re quirements related to Part C of the CAA, related to prevention of significant deterioration and visibility protection.

 Section 110(p) requires states to submit “reports” according to the Administrator’s schedule, “relating to emissions reductions, vehicle miles traveled, congestion levels, or any other information the Administrator may deem necessary to assess the development effectiven ess, need for revision, or implementation of any plan or plan revision” for a SIP. Also known as “infrast ructure SIP” requirements, read ers should refer to the “Guidance on Infrastructure State Implementation Plan (SIP) Elements under Clean Air Act Section s 110(a)(1) and 110(a)(2); September 2013; http://www.epa.gov/oar/urbanair/sipstatus/infrastructure.html

. General

 Section s 169 A and 169B focus on visibility protection for Feder a l class I areas and require the EPA to promulgate regulations establishing requirements for implementation plans to assure reasonable progress towards improving visibility

. To do this, the EPA has codified the regional haze program requirements in 40 CFR 5 1.308 and 51.309

. Regional Haze

 Section 172(c)(3) is a part of Part D, Subpart 1, which describes NAA SIP requirements for all criteria air pollutants (CAPs)

– carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter, and sulfur dioxide

– that, unless superseded by subsequent NAAQS

- specific subparts, apply to SIPs for NAA s submitted to the EPA

. This section includes a requirement that such SIPs include a current inventory of actual emissions in a NAA

. It allows the EPA Administrator to require periodic updates needed to determine if the general requirements of nonattainment SIPs (i.e., Subpart 1) are met. General

 Section 175A describes maintenance plans, which are SIP revisions that provide for the maintenance for 10 years of any primary NAA QS for which an area has been redesignated to attainment and may include additional control measures necessary to ensure this maintenance. U pdated emissions inventories are to be included in a main tenance plan. GeneralEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

6  Section 182(a)

- (f ) provide SIP requirements for areas designated as nonattainment for the ozone NAAQS and classified as Marginal and above

.
o Section 182(a)(1) requires a current and comprehensive inventory of actual emissions of all sources of ozone precursors to be included in a SIP

.
o Section 182(a)(3) (A) requires periodic inventories to be provided until an area is redesignated to attainment no later than the end of each 3

- year period after the submission of the inventory for 182(a)(1).

o Section 182(a)(3) (B) requires areas classified as Marginal and above to include in their SIP a requirement for stationary sources of NO X and volatile organic compounds (VOC) to provide the state with a statement showing actual emissions of NO X and VOC.

o Section 182(c) defines major sources for areas classified as Serious as sources that emit or have the potential to emit at least 50 ton s of VOC per
year.

o Section 182(d) defines major sources for areas classified as Severe as sources that emit or have the potential to emit at least 25 tons of VOC per
year.

o Section 182(e) defines major sources for areas classified as Extreme as sources that emit or have the potential to emit at least 10 tons of VOC per
year.

o Section 182(f) requires that all major source requirements for VOC also apply for NO X unless a waiver is received. Ozone

 Section 182(b)(1) includes SIP requirements for ozone NAAs classified as Moderate and above.

o Section 182(b)(1)(A) requires a rate of progress (ROP) demonstration, and describes requirements for annual reductions in VOC and NO X emissions as necessary to attain the ozone NAA QS.

o Section 182(b)(1)(B) requires a baseline emissions inventory for NO X and VOC from all anthropogenic sources in the NAA to be included in ozone SIPs for purposes of ROP/RFP. Ozone

 Section 182(c) (2) provides a SIP requirement for ozone NAAs classified as Serious and above

.
o Section 182(c)(2)(A) requires an attainment demonstration based on photochemical modeling. A modeling inventory is needed for the attainment demonstration analysis.

o Section 182(c) (2)(B) requires a RFP demonstration, and describes requirements for a timeline of VOC emissions reductions

. RFP demonstrations must include baseline emissions for comparison against the emissions reductions. OzoneEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

7  Section 182(j) (1) requires states in a multi

- state ozone NAA to take all reasonable steps to coordinate, substantively and procedurally, the revisions and implementation of SIPs for a multi

- state ozone NAA. Ozone

 Section 189(a)(2) in Part D, Subpart 4 provides a differen t and earlier schedule (18 months rather than 3 years) for PM SIPs than does the general provision in Part D, Subpart 1. PM 2.5

 Section 189(b)(3) (also Part D, Subpart 4) defines major sources in Serious PM NAAs as sources that emit 70 tons per year of PM 10 . Inventories for PM SIPs for Serious NAAs should include these smaller point sources using the lower threshold . T he appropriate threshold for PM 2.5 areas needs to be defined by an EPA rule

. PM 2.5



### 1.4 Summary of Guidance Contents
T his guidance document wi ll define parts of and considerations for emissions inventories to meet SIP requirements for complying with the 8

- hour ozone NAAQS, [ the PM NAAQS (2 4

- hour and annual) ] , and the regional haze regulations

. Section 2 p rovide s an overview of the creation, documentation, and submission of the planning inventories

. Section 3 has subsections for each of the separate inventory requirements o r recommendations, with details provided for all requirements except the base year and projected emissions inventories

. Section s 4 and 5 provide the detailed guidance on developing base year emissions inventories and projected emissions inventories, respectively

.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

8 

## 2 SIP Inventory Overview There are two categories of emissions inventories associated with SIP development: planning inventories and modeling inventories

. Modeling inventories are used for modeled attainment demonstrations

. Planning inventories are any other inventories associated with SIPs. The primary focus of this guidance is the planning inventories, whereas the emissions modeling guidance guidance is provided separately in the Modeling Guidance document ( see Section 1.2 )

. Generally, the EPA recommends that the planning inventories and modeling inventories be consistent, though there are exceptions. The exceptions are noted where they arise throughout this g uidance and the Modeling Guidance ; however, the EPA encourages air agencies to minimize inconsistencies.
The many aspects of p lanning inventories are covered more thoroughly in Section 3

. These aspects include the timing for submitting the various inventory components, the inventory preparation plan (IPP) , the base year NAA inventory, the RFP baseline inventory, the ozone periodic inventory, the ozone emissions sta tement requirement for SIPs, the maintenance inventory, the attainment projected inventory for the NAA , public hearings, and inventory approval by the EPA

. In this section, we provide an overview of the creation, documentation, and submission of the planni ng inventories

. Section 2.1 lists the various steps associated with building the planning inventory parts of a SIP and identifies the relevant sections of this doc ument that address those s t eps

. The discussions between air agencies and the EPA regarding the inventory approval process is described in Section 2.2

. In Section 2.3 , we list all of the required inventory components, including modeling inventories t hat are needed for ozone, PM 2.5 , or r egional h aze , but otherwise defer to the M odeling G uidance for the factors for air agencies to consider in building those inventories

. In Sections 2.4 , and 2.5 , we describe other federal emissions reporting requirements that are r elevant to NAAQS implementation and provide definitions of key terms needed to understand, develop, and submit emissions inventories for SIPs.



### 2.1 Recommended Steps for Building the Inventory Part s of a SIP Throughout this document, we describe many technical components that c ould be included in inventories in a SIP for ozone, PM 2.5 , or regional haze implementation

. Before air agencies start to create those components, it is important to recognize that there is a process associated with building them

. This section describes the process agencies should undertake for a successful inventory development and submittal effort

. The inventory development process involves both required and optional steps

. Some optional steps may be take n by the air agency if it believe s it is in its best interest to do so, and optional steps can also become critical to a particular SIP development process and identified as such by an EPA regional office

. Thus, a fundamental part of the process is establishing and maintaining open lines of communicati on between the air agency and the respective regional office . The regional office should be viewed by the air agency as the typical starting point for questions related to planning and modeling inventory development, and the regional office staff will dire ct questions needing EPA headquarters input as they arise

.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

9 A key aspect of this guidance is identifying opportunities for states to leverage existing work to help them meet the implementation requirements. This starts in Section 2.4 with a description of how work done in support of the National Emissions Inventory can be helpful for the SIP inventory work.

Table 2 provides a list of steps for completing the planning inventory and related parts of a SIP

. The list is provided in groups of steps that occur in phases presented roughly in chronological order

. The second column of the table indicates the section(s) of this document the give more information on the particular step.

Table 2 : Steps for b uilding the i nventory p art s of a SIP

Inventory

- related SIP development step Document section Planning

 Review this guidance

. All

 Become familiar with inventory development resources

. 1.1 1.2

 During development of the Inventory Preparation Plan , clarify and discuss the inventory approval process that your regional office will use , including all requirements, reporting formats and elements to be included, timing, and technical documentation contents

. 2.2 (general) 3.1 (timing)

 Understand required and potentially required inventory components for the SIP

. Determine which inventories must be created for your SIP. 2.3

 Understand inventory definitions and data requirements

. 2.5

 Understand timing requirements of submitted components

. 3.1

 Prepare and finalize the Inventory Preparation Plan

. 3.2

 Understand requirements and choose key inventory features, including inventory year (s) , the pollutants and precursors to be included, and priority emissions

sources

. 4

Creating Inventories

 Assess what inventories already exist that can be used as a starting point

. 2.4 3.3

 Create base

- year planning inventories

. 4

 Quality assure and refine base year inventory data in accordance with the IPP and/or Quality Assurance Project Plan (QAPP)

. 4.9

 Create projected planning emission inventor ies

. 5

 Quality assure and refine projected planning emission inventories in accordance with the IPP and/or QAPP. Preparing Documentation

 Review requirements with respective regional office in light of the particular challenges associated with a given SIP development process, such a first nonattainment SIP development for a state, area, or air agency staff

. 2.2

 Prepare documentation

. 3. 10 Public Hearings 3.9 Submit to the EPA for Approval 3.10Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

10 

### 2.2 Discuss the Inventory Approval Process with EPA Early in the SIP planning process, air agencies should discuss the emissions inventory approval process for that specific SIP with their respective EPA regional office

. T hese discussion s should address the tangible items (e.g., reports, data files, summary spreadsheets) that will be delivered to the EPA as necessary to support EPA’s review and approval

. Of the emissions inventori es that air agencies submit to the EPA , those that are deemed to be of “regulatory significance” will require EPA approval

. In general, this means that the approval process will include the emissions inventory as a component of a SIP submittal that require s EPA review and approval.
As new issues arise during the SIP development process, air agencies or the EPA regional office s may need to reassess the previously discussed inventory approval process

. Both agencies should be aware of possible changes that are needed as the inventory development process occurs, and either party should raise concerns about the need for discussion and possible revision of the process

. Details of the process and documentation can be modified through additional discussions as the n eed arises

. As t he inventory development process works far better when lines of communication remain open, the EPA encourages periodic coordination meetings or check

- ins during the inventory development periods.

Table 3 provides a list of tangible reports, summaries, and data files that could be included as part of the inventory efforts for SIPs

. While many of these items are needed to meet statutory and/or regulatory requirements, the form of reports, summaries, and data files to be included need to be clarified by the regional office at the start of the inventory development process for SIPs

. States should discuss and confirm with the EPA regional office th e items to be included in the SIP to avoid inadvertent omission of items required for approval of the inventory parts of the SIP.

Table 3 : Tangible products for p ossible i nclusion in i nventory e fforts

Inventory Item for SIPs Ozone [ PM 2.5 + ] Regional Haze Planning Inventories Inventory Preparation Plan X X Emissions Inventory Report, with explanations of methods, quality assurance and emissions summaries

. All inventories can be inc luded in such a report, including base year and projected inventories

. The inventories to be included depend on the NAAQS , the nonattainment classification, and the stage of implementation (initial SIP, redesignation, etc.)

. X X

Spreadsheets of emissions summaries included in the inventory report X X
Detailed emissions inventory files, databases, or spreadsheets X X Modelin

g Inventori es Modeling Demonstration Report

– The emissions information can be a section in a larger report or could have its own report

. The content should i nclude methods, quality assurance, and emissions summaries for the modeling inventories, X XEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

11 including projected inventories

. A statewide emissions summary is needed, and this can be included in the planning inventory SIP for convenience. Spreadsheet summaries of emissions inventory used for modeling X X Detailed emissions inventory files, databases, or spreadsheets X X Detailed data about emissions controls used to model attainment X X Other Emission Statement SIP showing the state’s program to require sources to submit emissions statements annually X

+ PM 2.5 Implementation Placeholder



### 2.3 Planning and Modeling Inventory Components
T he ozone, PM 2.5 , or regional haze implementation rules ha ve specific inventory requirements for SIPs to

su pport attainment, maintenance , and/or reasonable progress

. Additionally, there are possible inventory details that could be required or advisable for various reasons

. One distinction between the inventory requirements of the O zone and PM 2.5 R ules versus the Regional Haze R ule is that the form er requires inventories for NAAs , while the latter requires statewide inventories

. This section provides a list for each of the three rules for the required and possible inventory components of SIPs , with additional d etails for the types of planning inventories

.
2.3.1 Ozone SIP Inventory Components T he Proposed Ozone Implementation Rule (40 CFR Part 51, Subpart AA ) , when finalized, will provide the regulatory requirements for inventories of actual emissions that support ozo ne NAAQS implementation by air agencies

. In Table 4 below, we list the inventory components that could be part of an ozone SIP and identify the governing portion of the CAA and the applicable guidance in which they are addressed

.

For state or other air agencies that perform modeled attainment demonstrations, please also refer to the Modeling Guidance ( http://www.epa.gov/ttn/scram/guidance_sip.htm ) , which includes a section on emissions inventories for modeling

. As part of that guidance, summaries are described for statewide inventories

. For convenience, these summaries of modeling inv entories can be submitted with the emissions inventory SIP even though they are not essential for meeting the planning inventory requirements

. In areas where modeled attainment demonstrations are not a required part of a SIP, the state or other air agen cy would not need to provide the statewide inventories for ozone.

Table 4 : Ozone SIP emissions inventory components

Inventory Component Required by CAA ? ( CAA Section ) Guidance Sections and/or Document(s) Inventory Preparation Plan This document, Section 3.2 Base year NAA inventory Yes 182(a)(1) This document, Section 3.3 and

Section 4 ROP/ RFP baseline NAA inventory (part of the ROP/ RFP plan (s) ; for Moderate and above areas) Moderate & above : 182(b)(1) (B) Serious & above: 182(c)(2)(B) This document, Section 3.4 and

Section 4Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

12 Inventory Component Required by CAA ? ( CAA Section ) Guidance Sections and/or Document(s)
Periodic NAA inventory Yes 18 2 (a)(3) This document, Section 3.5 and

Section 4

Maintenance NAA inventor y Yes + 175A(a) This document, Section 3.7 and

Section 4 Attainment p rojected inventory for the NAA ‡ This document, Section 3.8 and Section 5 Source Emission Statements requirement for SIPs Yes 182(a)(3)(B) This document, Section 3.6

Inventories for modeled attainment demonstrations (base and projected attainment year) Yes ∆ 182(c)(2)(A) Modeling Guidance . Summaries of

statewide inventories (base and projected attainment year) are needed for review by the EPA

. Public hearing requirement for SIP inventories Yes 110(a)( 2 ) This document, Section 3.9 Planning inventory documentation This document, Section 3.10

+ Maintenance NAA inventories are only associated with maintenance SIPs rather than attainment demonstration SIPs. ‡ If this inventory is the me chanism by which the ROP/RFP plan requirements will show the emissions reductions required for ROP/RFP, then this inventory or its summary would necessarily become part of the ROP/RFP plan(s). Motor vehicle emissions budgets for purposes of transportation conformity are the on

- road portion of the projected emissions associated with the ROP/RFP plan. ∆ While modeling inventories are not an explicit requirement of the CAA, it is presumed here that state s would not be a ble to perform credible modeled attainment demonstrations without modeling inventories.

2.3.2 Annual and 24

- Hour PM 2.5 SIP Inventory Components [ PM Implementation Placeholder ]

Table 5 : PM 2.5 SIP emissions inventory components

Inventory Component Required by CAA ? (CAA Section) Guidance Sections and/or Document(s)

2.3.3 Regional Haze SIP Inventory Components The Regional Haze Rule (40 CFR Part 51 , Subpart P ) provides the regulatory requirements for inventories of actual emissions supporting r egional h aze implementation by state or other air agencies

. In Table 6 below, we list the inventory components that could be part of a Regional Haze SIP and identify the applicable guidance

. States are also required to periodically report on emissions progre ss at 5

- year intervals to ensure that they are on track to meet the established visibility goals. To make this comparison, states have toEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

13 compare the inventories from two distinct time periods

. These reports are due in the form of a SIP revision every five years

. Additional information is available on how to select inventories for comparison in “ General Principles for the 5

- Year Regional Haz e Progress Reports for the Initial Regional Haze State Implementation Plans ” ( http://www.4cleanair.org/Documents/haze_5year_4

- 10

- 13.pdf ).
Unlike the requirements for the ozone and PM 2. 5 NAAQS, the R egio nal H aze Rule requires statewide planning inventories rather than inventories for only a smaller NAA

. The Regional Haze Rule in 40 CFR 51.308(d)( 4 )(v) also requires the statewide inventory of emissions to include emissions for a “baseline ” year and for the most recent year in which data are available (“current year”)

. In practice, the “baseline” inventory has needed to reflect a year from the 2000

- 2004 baseline period. A separate “current year” inventory requirement exists, and for the ini tial Regional Haze SIPs, the baseline year and current year inventories are fulfilled with the same inventory . For the subsequent 5

- year progress report and 10

- year SIP revisions , the current year inventory will reflect an updated inventory from that initi al baseline using a more current year

.
Table 6 : Regional Haze SIP emissions inventory components

Inventory Component Required? (CAA Section) Guidance Sections and/or Document(s) Inventory Preparation Plan This document, Section 3.2
Baseline statewide inventory Yes 169A(b) + This document, Section 3.3 and

Section 4 Current year statewide inventory Yes 169A(b) + This document, Section 3.5 and

Section 4 Progress Report, including a n updated current year statewide inventor y and other emissions summaries and analyses Yes 169A(b) + This document, Section 3.5 and

Section 4

Projected statewide in ventory Yes 169A(b) + This document, Section 3.8 and

Section 5 Inventories for modeled reasonable progress (baseline and projected) Yes ‡ Modeling Guidance Public hearing requirement for SIP inventories Yes 110(a) (2) This document, Section 3.9 Planning inventory documentation This document, Section 3.10

+ CAA 169A(b) provides the authority to provide guidelines to the s tates on appropriate technique s and methods to implement the v isibility protection goals in the CAA. This has been done through regulations as codified in 40 CFR 51.308 and 51.309. ‡ While modeling inventories are not an explicit requirement of the CAA, it is presumed here that state s would not be able to perform the required modeling credibly without modeling inventories.



### 2.4 Other Relevant Federal Emissions Reporting Requirements The Air Emissions Reporting Rule (AERR), 40 CFR Part 51, Subpart A, requires states to provide to the EPA annual statewide emissions inventory data, regardless of whether that state has nonattainment

areas

. This regulation requires reporting of actual emissions of c arb on m onoxide ( CO )
, NO X , VOC, SO 2 , PM 2.5 , particulate matter with diameter ten microns and less ( PM 10 ) , and NH 3 . For PM 2.5 , the AERR requires states to report primary (i.e., “direct”) PM 2.5 , whic h is defined as the sum of filterable PM 2.5 andEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

14 condensable PM. The agencies are required to report the filterable PM 2.5 and condensable PM separately where they are present from the source. S tate s may delegate the reporting requirements to local air agenc ies. Tribes can also submit these data to the NEI, but are not required to do so

. These data are used by the EPA ’s Office of Air and Radiation ’s (OAR) Office of Air Quality Planning and Standards (OAQPS) to build the NEI, and a complete version that includes all sources of emissions (with minor exceptions) is released every three years.
The AERR includes both triennial and annual statewide reporting requirements, with more extensive reporting requirements for triennial inventory years. For the in terim annual inventories, reporting is limited to emissions data from only the larger point sources (Type “A” sources), as defined by Appendix A of 40 CFR Part 51, Subpart A. For the triennial inventories, lower point source thresholds are given in Appendi x A, consistent with the definition of major sources in 40 CFR P art 70 . A ll other sources of emissions must be reported as nonpoint or mobile sources on a county basis in the triennial submissions

. Additionally, lower point source thresholds may apply to o zone, PM 10 6 , and CO NAA s , depending on the area’s nonattainment classification

.
The AERR requirements are relevant for SIP planning inventory purposes in several ways

. First, the AERR and its associated EIS (data system) provide the appropriate format for inventories for electronic transfer to the EPA

. Second, AERR

- based inventories are often used as a starting point for SIP inventories

. Third, in some cases, AERR submissions can meet some of the inventory requirements described in this document

. Finally, t he resources provided by the EPA for states to meet their AERR reporting obligations, such as emissions inventory tools and models, associated documentation, emission factors, new emissions methods, and quality assurance approaches, can assist inventory de velopers when making inventories for SIP planning and modeling purposes.
As a point of clarification, air agencies must meet all relevant planning inventory SIP requirements regardless of the availability or use of the EPA data associated with the AERR/NEI process. While the EPA resources can be helpful to states in meeting those requirements, the SIP requirements and the associated public review and regional office approval process are independent requirement s that must be met

. It would not be sufficient to merely point to the EPA ’s publication of the NEI as having met the SIP emissions inventory requirements

. However, it may be sufficient for a state to submit as a SIP revision an inventory that contains some or all of the same data as in the NEI, with sufficient justification and public comment process.



### 2.5 Emissions I nventory Definitions Emissions inventory work requires knowledge of many terms and codes

. In this section, we define the terms relevant to inventories that are u sed throughout this document

. This section also references external materials needed for obtaining definitions of all valid fields that can be used for building inventories, which are based on the tables used to submit data to the EPA for the AERR

. Many de finitions relevant for emissions inventories are defined in the CAA or codified in the AERR and the implementation rules

. These are included here for convenient reference in this document to have in a

6 At this time, there is no separate lower reporting threshold for PM 2.5 .Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

15 single location and because these terms are used throug hout this document. Without these definitions, the meaning of the subsequent sections would be less clear. The sample below is not intended to represent a comprehensive list of inventory related definitions

.
2.5.1 Source Category/Data C ategory Traditionally, the term “source category” has been used to identify the major types of emissions inventory groupings: stationary point sources, stationary area (or nonpoint) sources 7 , on

- road mobile sources, nonroad mobile sources

. In addition, fires and biogenic sources are sometimes included as additional source categories

. In practice, some inventories have started including large moveable facilities, such as asphalt plants, in the point sources inventory without associating them with a specific county

. Additionally, so me mobile sources such as locomotives and commercial marine vessels (CMVs) are treated as nonpoint data (i.e., the formatting of it) for the purpose of reporting these data to the EPA (see also Section 4.8.5 as well as the EIS information referenced in Table 1 )

. Similarly, rail yards are treated as point data.

With the advent of the EIS at the EPA , the preferred term for indicating subsets of inventory data has become “data category” rather than “source category” , because the groupings have much more to do with how the data are created and the data structure than the features of the actual emissions sources included in the category. For example, locomotives and commercial marine vessels are included in the nonpoint data category for inventories in the EIS , but in fa ct are nonroad mobile sources. Additionally, the EIS ushered in a new data category called “events,” which are typically wildfires or prescribed fires (agricultural fires are part of the nonpoint data category) , but in principle could include other significant, short

- duration, emissions events 8

.
2.5.2 Types of Emissions: A nnual, S easonal, A ctual, Potential, and A llowable Various terms are used in this and other documents to reference various types of emissions

. Here, we provide a brief list of definitions associated with various emissions types.

Annual emissions are defined in the AERR (40 CFR 51.50) as actual emissions for a plant, point, or process that are measured or calculated to represent a calendar year. This means that annual emissions should include all emissions of the relevant sources at a facility or from a nonpoint or mobile process occurring during a calendar year

. In general, unless otherwise specified, annual emissions means actual emissions, as defined below.

Summer day emissions means an average day’s emissions for a typical summer work weekday

. T he state will select the particular month(s) in summer and the day(s) in the work week to be represented. The

7 Over time, stationary area sources have been renamed “nonpoint” sources to avoid confusion with the air toxics regulatory term “area sources”, which in fact are often sources that meet the criteria pollutant definition of point sources. Likewise, the term “stationary” is often ignored in common use for both the point source and nonpoint labels.
8 While the EIS is not currently configured to accept event data other than for fires, this means that the idea of an “event” could be expanded to other types of ev ents that are not currently inventoried because of the difficult nature and non

- routine nature of these types of emissions.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

16 selection of conditions should be coordinated with the conditions assumed in the development of ROP/RFP plans and/or emissions budgets for transportation conformity to allow comparability of daily emissions estimates

. The EPA advises states to make these decisions in consultation with their regional office.
[PM2.5 Implementation Placeholder]

Actu al emissions means the emissions of a pollutant from an affected source determined by taking into account actual emission rates associated with normal source operation and actual or representative production rates (i.e., capacity utilization and hours of operation) (40 CFR 51.491)

. This is in contrast with potential emissions or allowable emissions

. See Section 4.1 for a description of selecting a year for creating actual emissions estimates.
Startup, Shutdown, and Malfunction (SSM) emissions are emissions that occur during startup, shutdown, or malfunctions at industrial facilities

. The emissions rate during these periods can be much larger than the routine emission s rate 9

. More about the startup and shutdown emissions in the SIP inventory context are described in Section s 4.3 and 4.8.1

.
Potential to emit means the maximum capacity of a stationary source to emit a pollutant under its physical and operational design (40 CFR 51.301) . Also called “potential emissions
, ” 40 CFR 51.301 also defines this term to specific that a ny physical or operational limitation on the capacity of the source to emit a pollutant including air pollution control equipment and restrictions on hours of operation or on the type or amount of material c ombusted, stored, or processed, shall be treated as part of its design if the limitation or the effect it would have on emissions is federally enforceable. Secondary emissions do not count in determining the potential to emit of a stationary source. Ä

As de scribed in “Potential to Emit: A Guide for Small Businesses” (EPA

- 456/B

- 98

- 003), potential to emit considers the design of your equipment and can also consider certain controls and limitations on the operation of the equipment

. Potential emissions can be e xpressed as potential controlled emissions , which are the pollutant emissions while a source is operating at the maximum design capacity, a schedule of 8760 hours per year, and considering the efficiency of the control equipment

. In contrast, potential unc ontrolled emissions are simply the pollutant emissions while the source is operating at the maximum design capacity and a s chedule of 8760 hours per year without factoring in controls.

Allowable emissions means the emissions of a pollutant from an affected source determined by taking into account the most stringent of all applicable SIP emissions limits and the level of emissions consistent with source compliance with all f ederal requirements related to attainment and maintenance of the NAAQS and the produc tion rate associated with the maximum rated capacity and hours of operation (unless the source is subject to federally enforceable limits which restrict the operating rate, or hours of operation, or both) (40 CFR 51.491)

.

9 On February 12, 2013, the EPA proposed SIP calls for 36 states whose SIPs include exemptions for excess emissions during SSM peri ods or other provisions with respect to excess emissions during SSM events that appear to be inconsistent with Clean Air Act requirements. See http://www.epa.gov/airquality/urban air/sipstatus/emissions.html for more information.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

17 2.5.3 Duration and Timing of E missions Inventory start date means the first day of the inventory period

. This can be used for compiling and reporting monthly or other shorter period emissions, including events.
Inventory end date means the last day of the inventory period. This can be used for compiling and reporting monthly or other shorter period emissions, including events.

Inventory year or Emissions year means the year for which emissions estimates are reported (40 CFR 51.50)

. See also “Emission Type” in codes Section 2.5.14

.
2.5.4 Data Elements The term data elements means parts of a data file that contain individual items of data

. These are also called fields or variables

. Examples of key d ata elements associated with emissions inventories include emissions; activity; emission factors; state/county identifiers; facility, unit, and process identifiers; plant
names; control measure codes; and process codes

. This list is just a sample and is no t intended to represent a comprehensive list of required codes (see also Section 2.5.7 ).

Note that emissions data categories (Section 2.5.1 ) are not a data element per se, but rather emissions inventory submissions usually are broken out into separate datasets for each data category

.
2.5.5 T hroughput and A ctivity Throughput means a measurable factor or parameter that relates directly or indirectly to the emissions of an air pollution source during the period for which emissions are reported (40 CFR 51.50 ). Throughput is also called a ctivity

. Depending on the source category, activit y information may refer to the amount of fuel combusted, raw material processed, product manufactured, or material handled or processed

. It may also refer to population, employment, miles travelled, or number of existing units

. Activity throughput is typic ally the value that is multiplied against an emission factor to generate an emissions estimate. Consequently, it is important to coordinate activity used for a given emissions source with the available emission factors for that source 10

.
There are some special types of activities always used for certain categories

. Examples for mobile sources include :

Vehicle Miles Traveled (VMT) : The number of miles travelled within a year or as an average daily value for all vehicles within a group (e.g., vehicle type, fuel type , and county). See also MOVES Technical Guidance ( http://www.epa.gov/otaq/models/moves/index.htm#sip ).
Vehicle population : The number of vehicles of a certain type and fuel usa ge within a group ( such as a county )

.

10 Some air agencies have raised the concern that throughput at industrial facilities is considered confidential business information, however, this field is required by the AERR. Since this field is “emis sion data” required by the AERR, it cannot be protected as C BI under CAA § 114(c).Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

18 Equipment population : The number of nonroad equipment units of a certain type and fuel usage within
a group ( such as a county )

.
2.5.6 Emission Factor s An emissions factor is a representative value that attempts to relate the quantity of a pollutant released to the atmosphere with an activity associated with the release of that pollutant. These factors are usually expressed as the weight of pollutant divided by a unit weight, volume, distance, or duration of the activity emitt ing the pollutant (e.g., kilograms of particulate emitted per megagram of coal burned). Such factors facilitate estimation of emissions from various sources of air pollution. In most cases, these factors are simply averages of all available data of accepta ble quality, and are generally assumed to be representative of long

- term averages for all facilities in the source category (i.e., a population average). E mission factors have long been the fundamental key to developing emissions inventories for air qualit y NAAQS implementation

. More information on emission factors is available from the Emission Factors and Policy Applications Center ( http://www.epa.gov/ttn/chief/efpac/index.html ) on the EPA website.
The general equation for emissions estimation is:

where:

E = emissions, A = activity total, EF = emission factor, and ER = overall emission reduction efficiency percent.

The ER term is the combination of the relevant percents related to emissions controls and rules that reduce emissions, as listed in Section 2.5.18

.

E mission factors are not limited to factors that are only repr esent broad national industry averages published by the EPA

. Emission factors can also be stack

- , process

- , unit

- , or facility

- specific, depending on the basis of the source test information

. Whether for a single facility or a group of facilities of the

sa me type, it i s still considered an emission factor for the purposes of this guidance

.
2.5.7 Emissions Reporting Data E lements The Proposed Ozone Implementation Rule and [ PM 2.5 I mplementation Placeholder] refer s to the AERR and this guidance for information on reporting data elements

. Since the AERR is focused on emissions submitted for the annual NEI inventory, it only includes definitions for those data and fields that are required by the NEI program

. Notably, for ozone SIP inventories, summer day emissions are required, but have been proposed in an AERR revision to be optional for NEI submittal purposes. Thus, the proposed AERR revision no longer define s summer day emissions. Thus, t he summer day emissions are defined in the sections above.
[PM2.5 Implementation Placeholder]Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

19 The many required and optional data elements for emissions i nventories are described in Excel files called Staging Requirements

. These files are comprehensive for all of the required and o ptional fields that can be submitted to the EPA for SIP inventories, not only the submissions for the NEI

. The shared field list for NEI and SIP inventories help s air agencies by promoting clarity and familiarity through common data element definitions acr oss multiple inventory requirements. The descriptions provided in those Excel files are very limited, so this document provides additional information for the most important of these fields. These spreadsheet s are available at the EIS Training website at http://www.epa.gov/ttn/chief/eidocs/training.html#eis using the links for “Staging Table Requirements

. ”

Alt hough many fields in the Staging Requirements are optional for official repor ting purposes , some of these fields can be critical for inventory development for SIPs and even the NEI

. By optional, we mean those fields that are either not explicitly required by the AERR or that are not enforced as needing to be provided to successfully submit the data to the EPA

. The list below identifies fields that are “optional” but that are strongly recommended to be included in all emissions inventories , documentation, and reporting as applicable for the sources in the state or NAA

. For example, control parameters are optional only because emissions controls do not exist on every unit and process in an inventory, thus the EPA cannot enforce this as a required field

. However , the control information is required by the AERR when it exists as part of the source.

Unit Description : This field describes the unit in words. It can be invaluable in determining incorrect source classification codes ( SCCs )

.
Unit d esign capacity : Unit design capacity means a measure of the size of a point source, based on the reported maximum continuous throughput or output capacity of the unit (40 CFR 51.50 ). Useful for boilers, this field is needed when trying to understand the cost per ton of pollutant emissions reduced associated with controls on boilers

. The cost per ton is generally higher for smaller boilers

. The design capacity can be critical in SIP planning for insuring that good decisions are made about controls on stationary boilers and other units

. While required by the AERR, the EIS does not enforce this field as many states do not have this information available

. By including these data in SIP inventory development, states can help to further improve the data available to them for decision making as well as for consideration by the EPA

.
Control measure : This field is a unique code for the type of control device or operational measure (e.g., wet scrubber, flaring, proc ess change, ban) used to reduce emissions (see 40 CFR 51.50 ). When assessing whether an emissions source can be further controlled to contribute emissions reductions needed for attainment, it is imperative to know whether there is a control measure include d on a unit or
process

. The type of measure is also needed to understand whether other controls can be added. The associated data elements such as control efficiency, capture efficiency, rule effectiveness, and rule penetration are all useful as well for t he same reasons

. These latter control parameters are also needed when calculating potential controlled emissions.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

20 Alternative facility names or identifiers : This field c an be very useful in matching the facility with other databases, such as the Toxics Release Inventory, the Federal Registry System, or the National Electric Energy Data System (NEEDS) database. If air agencies change their agency IDs (facility, unit, proce ss, and release point) from one year to the next, this table can help prevent creating duplicates in the EIS and other databases.

EIS IDs : While the EIS Facility ID, Unit ID, Process ID, and Release Point ID (see Section 2.5.15 ) are not required by the AERR or for SIP inventories, it is the standard by which the EPA compiles and reports all point source inventories

. The EPA reports and modeling all use these EIS IDs , and so to the extent air
agency databases can use these IDs in their data systems, it helps facilitate matching across the many purposes for inventories.
Release Point Geographic Coordinates : As described in Section 2.5.17 , the EIS and inventories generally can have location coordinates (i.e., latitude/longitude) for a facility or at individual release point locations

.
2.5.8 Point S ources As defined by the AERR in 40 CF R 51.50, p oint sources are large, stationary (non mobile), identifiable sources of emissions that release pollutants into the atmosphere. A point source is a facility that is a major source under 40 CFR part 70 for one or more of the pollutants for which r eporting is required by 40 CFR 51.15 (a)(1). This does not include the emissions of hazardous air pollutants, which are not considered in determining whether a source is a point source for ozone, PM 2.5 , and regional haze emissions inventory development and reporting. These point sources can be associated with a single point or group of points in space

. Examples of i mportant point source emissions categories include power plants, industrial boilers, petroleum refineries, cement plant s, and other industrial p lants.
According to the ozone and PM 2.5 i mplementation rules, t he AER R governs the size above which sources

are inventoried as point sources

. While the AERR also requires data from state agencies for use in the NEI, the AERR emissions point source thresholds apply to all inventories provided to the EPA , including SIP inventories. The AERR bases the criteria on a potential to emit emissions size threshold

. Table 7 provides the potential to emit reporting thresholds included in the AERR

. “Type B” is the terminology in the rule that represents the lower emissions thresholds required for point sources in the triennial NEI
years

. For evaluating this criterion, it is appropriate to use potential controlled emissions for controlled

sources

. As shown in the table, special requirements apply to NAA sources, wher e even lower thresholds
may apply depending upon the severity of the NAA classification

.

A ir agencies may include point sources at even lower levels in their NEI or SIP

- related inventories

. The AERR potential to emit thresholds simply provide a minimum requirement

. Depending on the nature of the nonattainment problem and the need to characterize smaller source s as point sources, the EPA regional offices may require or encourage lower thresholds so air agencies can produce effective SIPs.

Type A source means a large point source with potential annual emissions of any CAP or CAP precursor greater than or equal to the corresponding emission threshold listed in the AERR and in this section.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

21 Type B source means a point source smaller than a Type A source with potential annual emissions of any CAP or CAP precursor greater than or equal to the relevant Type B emission threshold listed in the AERR and in this section

. Type B point sources are required by the AERR to be included in a state or local inventory submission for point sources in the triennial years and are applicable to SIP planning and modeling inventories as well.

Table 7 : Point source reporting thresholds (potential to emit) for criteria

pollutants in the Air Emissions Reporting Rule 11

Pollutant Triennial NEI thresholds: potential to emit (tons/yr)

Everywhere (Type B sources) NAA s ources *
1 SO2

................. ≥ 100 ≥ 100 2 VOC or NOx

.... ≥ 100 O 3 (M oderate) ≥ 100 3 VOC or NOx

.... ................................ . O 3 (S erious) ≥ 50 4 VOC or NOx

.... ................................ . O 3 (S evere) ≥ 25 5 VOC or NOx

.... ................................ . O 3 (E xtreme) ≥ 10 6 CO

.................. ≥ 1000 O 3 (all areas) ≥ 100 7 CO

.................. ................................ . CO (all areas) ≥ 100 8 Pb

................... ≥ 5 12 ≥ 5 9 PM 10 ............... ≥ 100 PM 10 (M oderate) ≥ 100 10 PM 10 ............... ................................ . PM 10 (S erious) ≥ 70 11 PM 2.5 .............. ≥ 100 ≥ 100 12 NH 3 ................. ≥ 100 ≥ 100

* Special point source reporting thresholds apply for certain pollutants by type of NAA

. The Clean Air Act specifies specific pollutants for separate NAAQS as follows: Ozone: VOC, NOX, CO; CO: CO; PM10: PM10.
2.5.9 Nonpoint S ources Nonpoint sources are also called “area sources”. These sources collectively represent individual sources of emissions that have not been inventoried as specific point or mobile sources

. These individual sources treated collectively as nonpoint sources are typically too small, numerous, or difficult to inventory using the methods for the other classes of sources

. Examples of key nonpoint sources include residential comb ustion, institutional and commercial boilers, agricultural burning, industrial and non

- industrial solvents and graphic arts, degreasing, most agricultural sources, and sources of dust including roads and construction.

2.5.10 On

- road Mobile S ources On

- road mobile sources are a lso called “highway mobile sources

. ” T hese sources are the motor vehicles (e.g., automobiles, buses, trucks) traveling on local and highway roads

. A motor vehicle is any self

propelled vehicle used to carry people or property on a street or hi ghway (40 CFR 51.50 )

. On

- road mobile sources should be estimated by the latest recommended on

- road mobile source models

.

11 On June 6, 2013, the EPA proposed to lower the reporting threshold for lead to 0.5 tons/yr. The lead threshold, however, is not relevant for this guidance because it does not cover lead NAAQS implementation.
12 The 5 ton threshold for lead is proposed to be reduced to 0.5 ton as of March, 2014.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

22 Currently, that means the MOVES model ( http://www.epa.gov/otaq/models/moves/ ) for all states but California, and the EMFAC 13 model ( http://www.arb.ca.gov/msei/modeling.htm ) for California.

2.5.11 Nonroad Mobile S ources Nonroad mobile sources are also called “off

- highway” mobile sources

. Thes e are defined as a nonroad engine or nonroad vehicle. As per 40 CFR 51.50 , a nonroad engine is an internal combustion engine (including the fuel system) that is not used in a [ on

- road ] motor vehicle or a vehicle used solely for competition, or that is not affected by sections 111 or 202 of the CAA

. Also as per 40 CFR 51.50 , a nonroad vehicle is a vehicle that is run by a nonroad engine and that is not a [ on

- road ] motor vehicle or a vehicle used solely for competition. Examples of nonroad mobile sources incl ude aircraft, airport ground support equipment, locomotives, CMVs , construction equipment powered by an internal combustion engine , agricultural equipment powered by an internal combustion engine , and lawn and garden engines and equipment

.
There are a variety of tools for estimating emissions from nonroad mobile sources

. The EPA develops and maintains approaches for a ircraft, locomotives, and CMVs , which are documented as part of the NEI program (for the latest approaches, refer to the latest NEI doc umentation available at http://www.epa.gov/ttn/chief/eiinformation.html )

. The EPA also has developed and maintains the NONROAD model ( http://www.epa.gov/otaq/nonrdmdl.htm ), which can also be run using NMIM ( www.epa.gov/otaq/nmim.htm ) 14

. Air agencies may update and customize the model inputs to give better emissions estimates for their state

. California has developed and used a state

- specific approach for estimating its nonroad source emissions, called OFFROAD2007 ( http://www.arb.ca.gov/msei/offroad/downl oads/models/offroad2007_1215_exe.zip ), which has now been replaced by category

- specific methods for many categories (see http://www.arb.ca.gov/msei/categories.htm #offroad_m otor_vehicles )

. As described by the website, the OFFROAD2007 model is still the default approach for categories not listed with newer methods on the website.

2.5.12 Events The EIS (starting with the 2008 NEI) introduced a new data category called events, which ar e discrete and large emissions sources that individually occur over a short period of time, but which can collectively result in a significant amount of emissions

. Example events captured by this data category include naturally occurring wildfire and a man aged prescribed burns

. In EIS, these data are stored as day

- specific events that can span many days for a given fire/event. More information on events data and its unique nature is available in Section 4.8.7

.
2.5.13 Biogenic S ources For the purposes of creating emissions inventories, b iogenic emissions come from natural sources

. They need to be accounted for in photochemical grid models, as many types o f biogenic emissions are

13 The EMFAC model name is not an acronym. The documentation and website for EMFAC do not include a further explanation of the name.
14 EPA is working to replace NMIM with the MOVES model. The latest recommended approaches will be included on the EPA’s Office of Transportation and Air Quality Websites.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

23 widespread and ubiquitous contributors to atmospheric chemistry leading to ozone and PM formation

. In the NEI, only the emissions from vegetation and soils are included, but other relevant sources include volcanic emissions, lightn ing, and sea salt spray

. Biogenic emissions from vegetation and soils are computed using models which utilize spatial information on vegetation and land use and environmental conditions of temperature and solar radiation to apply emission factors. The mode l inputs are typically horizontally allocated (gridded), and the outputs are gridded biogenic emissions which can then be summed for use in planning inventories and speciated and utilized as input to photochemical grid models

. As described in Section 4.8.6 , a variety of models are available to estimate the emissions from vegetation and soils.

2.5.14 Inventory Codes Th e list provided below is a sample of the codes that can be used in building inventories; it is not a comprehensive list of codes that should be used in building inventories

. The EIS is the repository for the most updated valid codes used for building inventories

. Dozens of tables of codes are ava ilable to EIS users from the “Reporting Code Tables” link on the EIS Gateway

. For others who do not have access to the EIS (e.g., contractors not working for a state, international users, and the general public), the EPA periodically posts Microsoft ® Access ® compilations of these codes at the main NEI website under the “EIS Code tables (including SCCs)” link.

Source classification c odes : An SCC means a proces s

- level code that describes the equipment and/or operation [ or practice ] that is emitting pollutants (40 CFR 51.50 ) 15

. These codes are 8 digits for point sources and 10 digits for nonpoint and mobile sources

. The codes have multi

- level descriptions, which

a re included in the EIS codes table

. These codes are also used in the emission factors online database WebFire ( www.epa.gov/ttn/chief/efpac/index.html )

. North American Industry Classification Syste m (NAICS) codes : The NAICS codes are U.S. Department of Commerce's codes for businesses by products or services and have replaced Standard Industrial Classification codes

. They are assigned to facilities in inventories to identify the primary industrial

ac tivity of the facility.

Federal Informati on Processing Standards (FIPS) s tate and c ounty codes : Federal Information Processing Standards (FIPS) codes means the system of unique identifiers maintained by the National Institute of Standards and Technology, which are used to identify counties and county equivalents (e.g., parishes, boroughs) of the U.S. and its territories (e.g., American Samoa, Guam, Northern Mariana Islands, Puerto Rico, and US Virgin Islands )

. In the EIS Codes Tables, additional codes have been added to support offshore regions and sources, such as asphalt plants, that do not remain in a single county during the entire year.

15 Several air agencies have raised the concern that SCC at industrial facilities is c onsidered confidential business information. However, this field is “emission data” required by the AERR and thus cannot be provided as CBI under CAA § 114(c).Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

24 Tribal codes : A three

- digit code th at represents the American Indian Tribe or Alaskan Native entity

. The EIS Table also identifies which EPA region is associated with the tribe

. These codes are used instead of FIPS state and county codes when reporting emissions from tribal areas.

Pollutant codes : Pollutant code mea ns a unique code for each reported pollutant assigned by the reporting format specified by the EPA for each inventory year (40 CFR 51.50)

. All of the criteria pollutants except for Lead have codes that describe them: CO, NOX, VOC, SO2, NH3, PM10

- PRI, PM10

- FIL, PM25

- PRI, PM25

- FIL, and PM

- CON

. Lead and the hazardous air pollutants ( HAP s) use numerical codes 16 to represent them, for example elemental l ead is 7439921 and elemental mercury is 7439976.

Control measure codes : Control measure means the name of the t ype of control device (e.g., wet scrubber, flar e, baghouse) or practice (e.g., product substitution)

. The EIS Code Tables use a three

- digit numeric control measure code to represent each of the different types of controls, and identifies each as a device or a practice

. The control device type codes were updated with add itional codes in 2013

. These codes are required when control devices are p resent because they are critical to understanding the nature of the emissions source and the possibility of additional emissions reductions to achieve attainment.

Emission calculation method : This field is the code describing how the emissions for a pollut ant were calculated, e.g., by stack test, continuous emissions monitor, EPA emission factor, etc. (40 CFR 51.50). This is a required field for inventories because it allows the EPA to get some sense of the quality of the emissions estimate

. Comment fields can also be used to further explain the origin of the emissions estimate.
Reporting period type : This field is the code describing the time period covered by the emissions reported, i.e., annual, 5

- month ozone season, summer day, or winter (40 CFR 51.50 ). This field is also called the e mission type code in some references.

2.5.15 Point source F acility D etails See also Section 2.5.7 , which points to the spreadsheets available that list all required and optional emissions inventory data elements.
Facility I nventory means the data tables of all facility information included in the EIS , but could also be used to refer to similar data tables for any inventory storage syst em

. The facility inventory is the complete list of facilities, units, processes, and stacks associated with all point sources

. It is designed to be the latest repository of facility information and needs updating only when changes occur to facilities

. The facility inventory concept was intended to allow facility data to be constant except where real changes occur, allowing easier building and submitting of inventories and encouraging the use of consistent facility IDs, unit ID, process ID, and stack IDs fro m one inventory year to the next.

16 These numerical codes are the unique numerical identifiers assigned and maintained by the Chem ical Abstracts Service (CAS) and are often referred to as CAS numbers or CAS registry numbers. The CAS numbers often appear with dashes embedded in the string of numbers, but these are dropped for most inventory reporting purposes.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

25 Physical address means the location address (street address or other physical location description), locality name, state, and a postal zip code of the facility. This is the physical location where the emissions occur; not the corporate headquarters or a mailing address (40 CFR 51.50 ).

Site name (also called Facility Site Name) means the name of the facility emitting emissions that are included in the inventory (40 CFR 51.50 )

.
EIS ID means any facility, unit, process, or r elease point (stack) ID generated by the EIS and intended to remain constant for the life of that facility, unit, process, or stack across inventory years

. The proper names of the EIS IDs in the EIS system are EIS Facility Site Identifier, EIS Emission Uni t Identifier, EIS Emission Process Identifier, and EIS Release Point Identifier.

Agency ID means any facility, unit, process, or release point (stack) ID generated by an agency reporting emissions to the EPA

. These IDs are used in the air agency data syste ms and may not match the EIS IDs described above

. The EPA tracks both the EIS IDs and Agency IDs within the EIS

. Using consistent agency IDs from year to year is highly encouraged , as it allows the EPA to more readily see which facilities are being reported for the AERR requirements

. Using inconsistent Agency IDs can result in duplicative facilities, units, processes, and release points within the EPA data systems.
Facility ID code (also called “Facilit y site identifier)” means the unique codes for a plant or facility treated as a point source, containing one or more pollutant

- emitting units (40 CFR 51.50 ) . The EPA's reporting format for a given inventory year may require several facility ID codes to ens ure proper matching between databases, e.g., the state's own current and most recent facility ID codes, the EPA

assigned facility ID codes, and the ORIS (Department of Energy) ID code if applicable.

Unit ID code means a unique code for the unit that generat es emissions, typically a physical piece of equipment or a closely related set of such equipment (40 CFR 51.50 ). An example of a closely related set of equipment is a boiler and its control equipment . The EPA's reporting format for a given inventor y year may require multiple unit ID codes to ensure proper matching between databases, e.g., the state's own current and most recent unit ID codes, the EPA

- assigned unit ID codes if any, and the ORIS (Department of Energy) ID code if applicable.

Process ID code is also called the “emission process identifier” and it means a unique code for the process generating the emissions, typically a description of a process (40 CFR 51.50 )

.
Release Point ID code means a unique code for the point where emissions from on e or more processes release into the atmosphere (40 CFR 51.50 )

. Traditionally called a Stack ID, but this was changed with EIS to acknowledge that many emissions releases do not come from stacks, such as fugitive emissions.
Release point type code means the code for physical configuration of the release point (40 CFR 51.50 )

. The physical configurations include fugitive, vertical, horizontal, goose neck, vertical with rain cap, and downward

- facing vent

. The first two t ypes are by far the most common

. The release point type is particularly important for dispersion modeling needed for permitting, risk modeling, and other
purposes.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

26 Release Point Diameter Measure (or Stack diameter ) means the inner physical diameter of a stack (40 CFR 51.50). This shoul d be measured at the exit release point of the emissions , and the e xpected reported units are feet

. Release Point Height Measure (or Stack height ) means physical height of a stack above the surrounding terrain (40 CFR 51.50)

. Expected reported units are fe et

.
Release Point Exit Gas Flow Rate Measure (or Exit gas flow rate ) means the numeric value of the flow rate of a stack gas (40 CFR 51.50)

. Various unit s are permitted by the EIS

.
Release Point Exit G as T emperature Measure (or Exit gas temperature ) means the numeric value of the temperature of an exit gas stream in degrees Fahrenheit (40 CFR 51.50 )

. Release Point Exit Gas Velocity Measure (or Exit gas velocity ) means the numeric value of the velocity of an exit gas stream (40 CFR 51.50 ) . Various unit s are permitted by the EIS

.
2.5.16 Alternative IDs In addition to the primary facility, unit, process, and release point IDs, alternative IDs can be very useful for matching information in a given inventory to other databases

. In the case of the EIS, it stores not onl y the EIS unique IDs, but also the air agency IDs

. Other IDs are stored as well, including the following:
EIA Plant Code (a.k.a ORIS Plant Code )

. This plant ID is defined by the U

. S

. Department of Energy (DOE) Energy Information Administration (EIA) and used in its EIA

- 767 form

. It has previously been defined as the Office of Regulatory Information System (ORIS) code, though that term is no long used by DOE

. The EPA ’s Office of Atmospheric Programs ’ (OAP) Clean Air Markets Division (CAMD) uses whatev er code was originally assigned to the facility as the tracking code for compiling data for its emissions markets in support of the acid rain program and NO X trading, in particular the CEMS data.

CAMD Unit ID

. In addition to the EIA facility IDs, CAMD use s unit IDs for storing the emissions markets data as well

. The EIS stores the unit codes used by CAMD as an alternative ID called “EPACAMD
, ” and the values are usually based on the CAMD hourly CEMS data reports

. These have historically also been referred to as ORIS Boiler or ORIS Unit IDs, though that reference is no longer valid.
IPM/NEEDS ID

. The EPA Integrated Planning Model (IPM) is used to forecast future

- year electricity demand and emissions. Underlying this model is t he National Electric Energy Data System (NE EDS ) database that contains the generation unit records used to construct the “model” plants that represent existing and planned/committed units in EPA modeling applications of IPM

. This database mostly uses IDs that are often the same as the EIA Plant Codes and the CAMD Unit IDs, but this database has more units than are included in the h ourly CEMS data

. In the EIS , the EPA stores these alternative IDs as “EPAIPM” IDs.
Toxics Release Inventory ( TRI ) ID is used by the EPA ’s Office of Environment al Information to build the T oxic s R elease I nventory from facility

- submitted facility

- total emissions to air, water, and land

. This database includes NH 3 , which is why it can be relevant to the NAAQS for PM 2.5 implementation

. In the EIS , the EPA stores these alter n ative IDs as “EPATRI” IDs.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

27 Federal Registry Service (FRS) ID is used by the EPA ’s Office of Environmental Information to link many EPA databases with facility information (see http://www.epa.gov/enviro/html/fii/index.html ).

2.5.17 Location D efinitions Geographic locations are critical in point source inventories for identifying the location of the emissions. In the EIS , locations can be provided for both the facility center and for individual release points

. Fugitive release poi nts have additional parameters that can be specified such as the orientation of the release, and these parameters are listed in the spreadsheets available that list all required and optional emissions inventory data elements, referenced in Section 2.5.7

.
Latitude Measure (or just latitude) is the measure of the angular distance on a meridian north or south of the equator. Reported as decimal degrees.
Longitude Measu re (or just longitude) is the measure of the angular distance on a meridian east or west of the prime meridian. Reported as decimal degrees.
Horizontal Accuracy Measure is the measure of accuracy (in meters) of the latitude/longitude coordinates.

In addit ion, refer to http://www.epa.gov/oei/ for more information on the proper usage of the following code set.

Horizontal Collection Method Code is the m ethod used to determine the latitude/longitude coordinates for a point on the earth. For example, 001 is address matching

- house number, and 004 is address matching nearest intersection.

Horizontal Reference Datum Code represents the reference datum used to determine the latitude/longitude coordinates. Options are: 001 (North American Datum of 1927), 002 (North American Datum of 1983) and 003 (World Geodetic System of 1984).
Geographic Reference Point Code represents the place for which geographic coordinate s were established. Code value should be 106 (e.g., point where substance is released).

2.5.18 Control Data E lements Control efficiency means the efficiency by which a control device or measure reduces emissions for a particular pollutant

. For emissions reporting in accordance with the AERR, this data element applies for both point and nonpoint sources and is called the “ Percent Control Measures Reduction Efficiency

. ” For point sources, the data element is included in the “ Control Pollutant Table ” of the facility staging table s

. For nonpoint sources, the data element is included in the “ Control Pollutant Table ” of the nonpoint staging table s . In the EIS , it is a percent and should be reported as a value greater than or equal to 0.1 and less than or equal to 99.9 ( the EIS allows for one decimal place only).

C apture efficiency means the percentage of an exhaust gas stream actually collected for routing to a set of control devices (40 CFR 51.50). It is sometimes combined within the v alue for the control efficiency, but unlike control efficiency it is not pollutant

- specific

. For emissions reporting in accordance with theEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

28 AERR, this data element is for point sources only, and it is called “ Percent Contro l Capture Efficiency ” and is included in the “ Control Approach Table ” of the facility staging table s

. It is a percent and should be reported as a value greater than or equal to 0.1 and less than or equal to 99.9 ( the EIS allows for one decimal place only).

Control Effectiveness means the percentage o f time or activity throughput that a control approach is operating as designed, including the capture and reduction devices. This percentage accounts for the fact that controls typically are not 100 percent effective because of equipment downtime, upsets a nd decreases in control efficiencies (40 CFR 51.50).

Control effectiveness i s a n estimate of the portion of the reporting period's activity for which the overall control system or measure (including both capture and control measures) were operating as des igned (regardless of whether the control measure is due to rule or voluntary). It applies to both point and nonpoint sources and is not pollutant

- specific

. For point source emissions reporting in accordance with the AERR, this data element is called “ Perce nt Control Approach Effectiveness ” and is included in the

“ Control Approach Table ” of the facility staging table s . For nonpoint source emissions reporting in accordance with the AERR, this data element is also called “ Percent Control Approach Effectiveness ” and is included in the “ Control Approach Table ” of the nonpoint staging tables

. In the EIS , it is a percent and should be reported as a value greater than or equal to 0.1 and less than or equal to 99.9 ( the EIS allows for one decimal place only)

. For non point, see also “rule effectiveness
, ” below.
Rule penetration means the percentage of a nonpoint source category activity that is covered by the reported control measures (40 CFR 51.50). For emissions reporting in accordance with the AERR, this data element is called “ Percent Control Approach Penetration ” and is included in the “ Control Approach Table ” of the nonpoint staging tables

. In the EIS , it is a percent and should be reported as a value greater than or equal to 0.1 and less than or equal to 99 .9 ( the EIS allows for one decimal place only).

Rule effectiveness means a rating of how well a regulatory program achieves all possible emissions reductions

. It is analogous to the “control effectiveness” above and in fact for emissions reporting in

accor dance with the AERR, this information is reported using the EIS Control Effectiveness field for nonpoint (see above).Rule effectiveness has traditionally been associated with nonpoint controls rather than point source controls. Like control effectiveness, it should reflects the assumption that controls typically are not 100 percent effective because of equipment downtime, upsets, decreases in control efficiencies, noncompliance, and other deficiencies in emission control . Rule effectiveness adjusts the

con trol efficiency from what could be realized under ideal conditions to what is actually emitted in practice due to less than ideal conditions

. The definition above is from the current version of the AERR (40 CFR 51.50 ) that is proposed to be replaced in 201 4

.
2.5.19 EIS Sectors , Tiers , and Facility Type Because emissions inventories are large and detailed, most reports about emissions inventories include summaries of the contents of those emissions

. Some summaries use the data categories described above (point, non point, on

- road, nonroad, events, and biogenic)

. For other summaries, that level ofEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

29 detail is not enough. The EIS SCC tables provide three other mechanisms for summar ies, all of which depend on SCC.

First, the SCCs have a four

- part description, and the firs t three levels of this description could be used as a summary category

. Second, the SCCs are assigned to “Tiers” using the fields “Tier 1 Description
, ” “Tier 2 Descripti on , ” and “Tier 3 Description

. ” These Tiers have been used traditionally as part of many EPA reports and trends for criteria emissions

. While wildfires are included in the “Miscellaneous” Tier 1, wildfires are sometimes separately broken out from Miscellaneous because of their natural origin and because they can be a large contributor for som e pollutants. Finally, the EIS Sectors can be used to summarize emissions (this is the field “Sector” in the EIS SCC code table). The EIS Sector was added with the creation of the EIS and allocates emissions to about 60 categories with multi

- pollutant inve ntories in mind

. Whereas the Tiers are more useful for criteria pollutants, the EIS S ectors work better for the combination of HAPs and CAPs

. The EIS Sectors can also be further aggregated to provide custom summaries; one example of this is presented in th e report “2008 National Emissions Inventory: Review, Analysis and Highlights” (EPA

- 454/R

- 13

- 005, May 2013).

2.5.20 Other Terms High electricity demand day (HEDD) means a summer day when demand for electricity is high. A study of the Northeast Corridor 17 air qualit y has indicated that NO X emissions from EGUs during HEDD periods may be significantly greater than emissions that occur on an average summer day.
Distributed generation means the use of small power generators sited at or near the point of energy consumptio n. This usually occurs during periods of peak energy demand or emergency loss of the normal EGU generating capacity . Distributed generation sources of electricity can include rooftop solar or wind sources , biomass combustion, as well as backup fossil fuele d generators or other engines. T he combustion sources of distributed generation can cause emissions that could be of interest for SIP planning purposes.

17 “High Electric Demand Day and Air Quality in the Northeast.” White Paper Prepared by the Northeast States for Coordinated Air Use Manageme nt. June 5, 2006. Available at: http://www.nescaum.org/documents/high

electric

- demand

- day

- and

- air

- quality

- in

- the

- northeast/final

- white

- paper

- hi

- e lectric

- demand

- day

- 06052006.pdf

.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

30 

## 3 SIP Inventory Requirements and Recommendations
As described in Section 2 , there are many required and potentially required inventory efforts needed as part of a SIP development effor t

. This section covers the fundamental attributes of planning inventories and thei r preparation

. The topics covered include the timing of the various inventory components (Section 3.1 ) , the inventory preparation plan (Section 3.2 )
, the base year inventor ies (Section 3.3 )
, the ROP/ RFP baseline NAA inventory (Section 3.4 ) , the ozone periodic inventory (Section 3.5 ) , the ozone emissions s tatement requirement for SIPs (Section 3.6 ) , maintenance invent ories (Section 3.7 ) , the projected inventor ies (Section 3.8 )
, public hearings (Section 3.9 ) , and submitting the inventory to the EPA for approval (S ection 3.10 )

. The details of inventory preparation for base year inventories and projected inventories are left for Sections 4 and 5 , respectively.



### 3.1 Inventory Component Timing Table 8 provides the timing requirements and recommendations (for optional items) for the inventory components of SIPs

. Where this table is inconsistent with the ozone, PM 2.5 , or regional haze regulatory
text that is applicable at the time a SIP is prepared and reviewed , the regulations have precedence over the information provided here.

Table 8 : Timing of emissions inventory components Inventory Component Required + : Timing
Inventory Preparation Plan Prior to preparation of emissions inventories covered by the SIP

.
Base year NAA inventory Ozone Within 2 years of the effective date of designations

ROP/ RFP baseline NAA inventory Ozone Moderate & above: W ithin 3 years of the effective date of designations

. Serious & above: Additional plan within 4 years. Periodic NAA inventory Ozone The end of each 3

- year period after SIP submittal until the NAA is redesignated to attainment. Source Emission Statements requirement fo r SIPs Ozone Within 2 years of the effective date of designations

. Base case statewide inventory Ozone ‡ With modeled attainment demonstration (for convenience, can be included with the inventory SIP)

. Attainment p rojected inventory for the NAA With SIP and/or ROP/RFP plan . On

- road portion can become the motor vehicle emissions budget. Baseline statewide inventory ∆ Haze With Regional Haze SIP (by December 17, 2007) and every 10 years beginning on July 31, 2018

.

Projected statewide inventory Ozone ‡

Haze With modeled attainment demonstration (for

convenience, can be included with the inventory SIP) With Regional Haze SIP (by December 17, 2007) and every 10 years beginning on July 31, 2018

. Progress Report, including periodic statewide inventory Haze Every 5 years from submittal of initial Regional Haze SIP

. Public hearing All Prior to submittal of inventory for approval by the EPA

.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

31 Inventory Component Required + : Timing Inventory documentation All With associated inventory

. Maintenance NAA inventory Ozone After attainment, with a redesignation SIP.

+ PM 2.5 requirements undergoing review and updating pending the prop o sed PM 2.5 Implementation Rule. ‡ Only required in association with modeled attainment demonstration. ∆ The baseline inventory and current inventory are treated here as they are in practice: as a single inventory.


### 3.2 Inventory Preparation Plan
A ir agencies can use IPPs as a planning tool to guide inventory preparation and to help ensure that emission estimates are of a high quality and consistent with CAA requirements

. In some cases, the EPA regional office s will have a preset list of expectations for air agencies to include in their SIP and will provide this information to the agency at the start of the SIP planning process

. In these cases, an IPP may not be needed, espec ially for air agencies with prior SIP development experience for a particular NAAQS.
The IPPs are an opportunity for state and local agencies to tell their EPA regional office how the y plan to compile their emissions inventories and allow the EPA to provide feedback prior to the agency spending resources in preparing their inventory

. They can also allow the EPA regional office s to coordinate to maintain consistency across attainment plans where that is advisable

. The IPPs can be especially valuabl e for agencies with new nonattainment pr oblems, less experienced inventory staff or for agencies otherwise needing additional feedback on inventory development

. If used, IPPs precede the development of inventories; therefore, the timing of IPPs is e arly in the SIP planning process

. The EPA recommends that air planning agencies coordinate with their regional office on the need for a plan, the timing of delivery of the plan, the response time back from the EPA on the plan , and any other IPP approval process d etails

. Agencies should recognize that time may also be needed in their planning schedule to addres s the EPA comments on the plan, while the EPA regional office s will attempt to provide as timely feedback as possible

. A high quality IPP could be a strong foundation for the emissions inventories used in planning and/or attainment modeling, which are themselves critical pieces of SIP development ; therefore, t he IPP should include enough details for the EPA to properly assess what the agency plans to do

. The content can include a number of key elements, a checklist for which is provided in Table 9

. The actual elements to include in a specific IPP can depend on a number of factors, depending on the needs of the state or local agency as well as the EPA for understanding the inventory pla ns

.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

32 Table 9 : Checklist of elements to c onsider for i ncluding in Inventory Preparation Plan s

IPP Element Essential for a High Quality IPP ? Inventory objectives

– the purpose and scope of the inventory Y The inventory year(s) and rational e for selecting them Y The pollutants to be included, including the expected definition of VOC (for inventories needing VOC) Y A list of inventories to be included with the SIP, including the forms (i.e., files, summaries) that the agency int ends to include in their SIP Y Plans for (or results of) identifying the most important source sectors to the nonattainment problem Y The source categories to be included, the emissions level(s) for defining point sources, and if available, the expected priority for these Y The plans for compiling the inventory, including any other known inventories and how the agency plans to assess and improve upon what is already available A summary of expected approach differences among different inventories that c ould be the same (e.g., between a base year NAA inventory and a base year modeling inventory) For projected inventories: The drivers for future

- year emissions growth and reductions Y +
The source categories to be forecast Y + The expected approaches for forecasting each source category Y + A plan for public review Important sources of emissions or other inventory uncertainties Quality assurance steps to be taken Y A schedule for inventory preparation, review, and submission to the EPA , including any plans to submit pieces of the inventory separately and in accordance with regulatory timeline requirements Y

+ If a projected inventory is required

.
In addition to Table 9 , other inventory planning resources may be of use for agency planning purpose s

. During the preparation of their IPPs, state and local agencies are referred to Volume I of the EIIP
g uidance av ailable at http://www.epa.gov/ttn/chief/eiip/techreport/volume01
, which discusses emissions inventory planning and development

. While somewhat out of date, the EIIP volumes still can help guide new inventory developers

. Users of that document should defer to this guidance where newer information is provided, such as updated versions of mobile models

. For stationary point sources, a good resource is EIIP Volume II, Chapter 1, Section 3

. For nonpoint sources, EIIP Volume III, Chapter 1, Section 2 gives nonpoint

- specific planning information

. The mobi le source volumes for EIIP are more out of date and the Office of Transportation and Air Quality ( OTAQ ) mobile source guidance is preferable.

A quality assurance plan should always be a part of the IPP

. In cases where a more formal QAPP is developed, the QAPP will satisfy the need for an IPP quality assurance plan

. In some cases, the EPA regional offices will include a QAPP or other QA requirement as part of their CAA Section 105 grant to a state that typically includes funding for emissions inventory development.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

33 For quality assurance planning , Chapter 2 of Volume VI, “ Quality Assurance Procedures and DARS software ” ( www.epa.gov/ttn/chief/eiip/techreport/volume06 ) provides some general guidance for quality assurance and some specific approaches to uncertainty evaluation

. Other quality assurance resources include Section 4.9 of this guidance , and quality assurance steps described in the latest NEI Technical Support Documentation available at the latest NEI documentation page link on the main N EI web page ( http://www.epa.gov/ttn/chief/eiinformation.html )

. Where air agencies are relying on their NEI submission as a starting point for meeting any SIP inventory requirements, a QAPP developed for that air agency’s NEI submission may offer a starting point for the SIP inventory QAPP.



### 3.3 Base Year Inventory The purpose of the base year inventory is to provide a current and comprehensive data source for emissions contributing to the air qua lity problem addressed by the SIP

. In the case of ozone and PM 2.5 , the inventory requirement is for the NAA , whereas for regional haze, the inventory requirement is for a statewide inventory

. As listed in Table 4 and Table 5 , the ozone [ PM 2.5 Implementation Placeholder ] requirements can also include statewide inventories as part o f the modeled attainment demonstration, and these can be included as separate inventory submissions included with the NAA inventory.

The general SIP provisions in CAA section 172(c)(3) explains that base year inventories should include a

“ comprehensive, ac curate, current inventory of actual emissions from all sources” in the applicable area

. Details associated with preparing a base year inventory are provided in Section 4 , including selection of year(s), temporal extent, spatial extent, pollutants to include, approaches for developing emissions, data codes, and quality assurance

. Additionally, CAA section 182( a)(1) provides a specific base year inventory requirement for ozone SIPs.
The base year inventory is the starting point from which the other SIP

- related inventories are derived

. While inventories used for the ROP/ RFP baseline, modeling, emissions projectio ns, and other inventories will not necessarily be identical to the base year inventory, these inventories should relate to the base year inventory with regard to the emissions sources included, pollutants, temporal aspect, and other key aspects that allow the SIP to be a coherent and connected plan across the various inventories. For planning purposes, the base year inventory provides a way for decision makers to consider the sources of emissions that contribute relevant pollutants and consider emissions re ductions strategies needed for the SIP.

Section 4.1 covers the choice of inventory years for the base year inventory

. The choice of the inventory year for the plan ning is a critical one that significantly impacts the workload of inventory staff and greatly depends on availability of data and timing of other inventory efforts required by the EPA

.
Section 4.2 covers the pollutants to be included in the base year inventory . These pollutants differ depending on the nature of the air quality problem for a given SIP

. Where feasible, the EPA encourages planning agencies to include pr ecursors for all ongoing nonattainment problems in a state, to promote efficiency in preparing multiple base year inventories, and to allow for the consideration of emissions reduction strategies that improve air quality across multiple air quality concern s and nonattainmentEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

34 issues

. In addition, states may wish to include emissions of HAPs , which can have co

- benefit reductions associated with strategies aim ed at reducing ozone, PM 2.5 , and/or regional haze.

T he spat ial and temporal extent of the base year inventories are also an important inventory characteristic

. These topics are covered fully in Sections 4.4 and 4.5

. Each of the implementation rules for ozone, PM 2.5 , or regional haze has different considerations and requirements associated with the planning inventories

. For example, ozone NAA inventories must include both ann ual and seasonal (i.e.,

summer day) emissi ons, whereas the regional haze inventories are only annual.

For ozone [ and PM 2.5 ] , the implementation rule [ s ] require s inventories for the NAA

. These inventories are called the base year inventory for the NAA. For regional haze, the inventory is commonly called the baseline inventory. For clarity here, we also call the regional haze inventory the baseline statewide inventory to distinguish it from a NAA inventory. These inventories may need to be updated through mul tiple iterations of a SIP, when they are used a baseline inventories for assessing progress for ROP/RFP or regional haze. More on this issue is provided in Section 3.4.2 on RFP/ROP for ozone and Section 3.5.2 on current year inventories for regional haze

. 

### 3.4 Rate of Progress and Reasonable Furth er Progress Baseline NAA Inventor y The ROP/RFP baseline NAA inventory is necessary for ozone NAAs design ated as Moderate and above

. This baseline inventory is part of a plan or plans that meet the RFP requirements as described by the CAA and the Proposed Ozone Implementation Rule , and summarized here.

3.4.1 ROP/RFP Requirements and Timing CAA section 182(b)(1)(A) requires Moderate and above NAAs to submit a plan to ensure a 15 percent VOC reduction (accounting for growth) by 6 years after the NAA designation , which is the Moderate area maximum attainment date

. Th e 15 percent reduction requirement is commonly called “ rate of progress ” or ROP. According to the Proposed Ozone Implementation Rule , air agencies must submit this plan within 3 years after the area’s nonattainment designation. This timing aligns with the Moderate NAA deadline f or submittin g attainment demonstration SIPs

. In addition, CAA section 182(c)(2)(B) requires each Serious and above ozone NAA to submit a plan to achieve a t least a further annual 3 percent VOC reduction

. Additionally, CAA Section 182(c)(2)(C) allows for su bstitution of NO X for VOC emissions reductions in the plan under certain conditions

. This requirement is also called “annual RFP

. ” As described by the Proposed Ozone Implementation Rule , the annual RFP requirement applies for any remaining 3

- year periods o ut to the attainment date beyond the first 6 years. According to the Proposed Ozone Implementation Rule , air agencies with Serious and above NAAs must submit this plan within 4 years after the area’s nonattainment designation. This timing aligns with the S erious and above NAA deadline for submitting attainment demonstration SIPs; however, these NAAs still must submit the plan for ROP within 3 years.

State s maintain the flexibility to submit plans early to provide more time for implementation of their SIP

co ntrol measures . The EPA recommend s that state s complete their ROP/RFP plan s as expeditiously asEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

35 practicable after designation to provide as much time as possible for sources to implement the emission reductions.
The associated terminology for the various plans and inventories can be confusing, and so the terminology used in this guidance is described here. In this guidance, we use “ ROP/ R FP plan” to refer generally to all plans

– i.e., those addressing just the 15 percent ROP requirement for Moderate areas as well as plans additionally addressing the annual RFP requirement. For Serious and above areas, s ince the timing allows that two separate plans for ROP and annual RFP could be submitted (i.e., at 3 years and 4
y ears after designations, respectively), it may also be necessary to refer to such plans separately. Consequently, this guidance uses “ROP/RFP plan(s)” to allow for the idea that multiple plans could be submitted. Lastly, in the case where the individual p lans must be referenced, they will be called “ROP plan” and “RFP plan

. ”

3.4.2 ROP/RFP Inventory Guidance The same ROP/RFP baseline NAA inventory is used for all ROP/ RFP plan ( s ) , regardless of whether they address the ROP requirement (for Moderate areas) or both ROP and annual RFP (for Serious and above)

. As implied by the name, these inventories include emissions data just for the NAA region and not other areas in a state. The purpose of the ROP/RFP baseline NAA inventory is to provide a reference point for deter mine the emissions reductions that must be achieve d for the 15 percent VOC (or NO X ) reduction and the subsequent 3 percent reductions for Serious areas and above out to the attainment date.

For ozone, VOC and NO X should be included in the ROP/RFP baseline NAA inventory. Further, the EPA expects that the year of the ROP/RFP baseline NAA inventory will be the same year used for the base year inventory for the NAA.
[PM2.5 Implementation Placeholder]

For Ozone, t he ROP/RFP baseline NAA inventory emissions should be provided using the same base year as is used for base year inventory for the nonattainment area. In most cases, the ROP/RFP baseline inventory should also have the same emissions values as are in the base year inventory for the NAA

. One key exce ption is that biogenic emissions should not be included in the ROP/RFP baseline.

I n some limited situations, the EPA has proposed that states have the option of selecting an appropriate and justifiable alternative year for the ROP/RFP baseline NAA invento ry, given that they follow certain require ments (see 78 FR 34190

- 34191). If this proposal is finalized and a state chooses to use an alternative ROP/RFP baseline year, this also changes the year to use for the base year inventory for the NAA so that the ba selines are using the same year

. The EPA also expects that the spatial extent of the ROP/RFP baseline NAA inventory will also match the base year NAA inventory so that they are both either “whole county” inventories or both consistently “partial county” in ventories. Section 4.4.1 provide s more information on partial county inventories.

In the event that updated ROP/ RFP p lan (s) are needed after initial submittal to me et the requirements of the Proposed Ozone Implementation Rule , the ROP/RFP baseline NAA inventory may also need to be updated. This can occur with significant methods changes, such as updated mobile models

. For example,Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

36 after an initial ROP/ RFP p lan has be en submitted as part of a SIP, a new mobile model may become available that alters the emissions estimates. It would be inconsistent to compare estimates from a new mobile model at the end of a 6

- year period to estimates using an o ld model at the beginning of that 6

- year period , and so the EPA c ould be unable to determine whether a 15 percent reduction (or subsequent 3 percent reductions) can be (or has been) achieved by an ROP/ RFP plan. Thus, an updated ROP/RFP baseline NAA inventory may need to be created using the updated mobile model to appropriately meet the requirements of the Proposed Ozone Implementation Rule

.
Additional ROP/RFP emissions reductions guidance is provided in Section 3.8.2

. [PM 2.5 Implementation Placeholder]



### 3.5 Periodic Inventor y T he Oz one Implementation Rules require s a periodic inventor y for the NAA, and the Regional Haze Rule requires a “current year” statewide inventory

. These inventories should be consistent with the base year (“baseline” for regional haze) inventory in the temporal extent (seasonal, annual, or both), spatial extent (statewide, NAA counties, partial coun ties), and sources inventoried. In some cases, it may also be advisable to have the emissions inventory methods of the periodic inventory consistent with the base
yea r inventory , but this decision should be made in consultation with the relevant EPA regional office

. Regional offices may consider additional relaxation of the consistency recommendation above in specific instances.

3.5.1 Ozone Periodic Inventory For ozone , the requirement in 182(a)(3)(A) is that the periodic inventory be submitted no later than each 3

- year period after the submission of the base year NAA inventory

. This language provides the flexibility to air agencies to submit sooner than 3 years, but no t later than 3 years

. If any other current NAA inventory is being submitted to the EPA for any reason, including ROP/ RFP plans, then states should consider also using that data to meet the periodic inventory requirement. Also, i f the air agency comes into attainment and receives a Clean Data Determination prior to the 3

- year period, or if a maintenance plan (with a maintenance inventory) is being submitted prior to or in sync with this 3

- year timetable, then the these actions are very likely to make it unne cessary for the air agency to submit a separate ozone periodic inventory

. Since the periodic inventory requirement in the CAA does not specify the degree of detail required for the periodic inventory, the EPA has defined the necessary components through th e AERR

. Thus, whether the inventory is submitted as a separate submission or through the AERR, it would need to be consistent with requirements of the AERR in order to meet the statutory period ic inventory requirements

. The periodic inventory does not have regulatory significance, unless it is relied on for purposes of a planning requirement such as an attainment demonstration or ROP /RFP plan. Rather, it is a check

- in with the air agency on how the emissions are trending. All inventories for the ozone NAAQS (other than the p eriodic inventory) have some regulatory significance because they are associated with required submissions such as maintenance plans, ROP/ RFP plans, and modeled attainment demonstration s

. These inventories all have public hearing requirements as described in Section 3.9 . As such, if a periodicEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

37 inventory is not serving another purpose that has regul at ory significance, the EPA has established a policy for deferring the public hearing on the periodic emission inventories and the approval of these inventories (s ee “Public Hearing Requirements for 1990 Base

- Year Emission Inventories for Ozone and Carbon Mo noxide Nonattainm ent Areas”, September 29, 1992; http://www.epa.gov/ttn/chief/old/memos/ei/phr_sep1992.pdf ). This policy defers the public hearing requirements until the time an area t akes a regulatorily significant action that relies on the inventory, such as adopting and submitting their attainment demonstration and/or ROP/RFP plans. However, in deciding whether to rely on that guidance, it is important to note that the EPA cannot act on the inventory submission until the public hearing requirement has been completed, and until that time, the EPA may face litigation alleging that it has failed to act on the inventory as required by the CAA.
To meet the periodic inventory requirement for ozone, the periodic inventories must include both annual and summer day emissions values

. Since these emissions fields are both allowed to be submitted to the EPA through EIS for the AERR, it is possible that the submission could meet the periodic inve ntory requirement if the conditions listed in Table 10 apply

. A s with all SIP requirements, air agencies should coordinate with the regional office regarding what is appropriate for a particular NAA.

Table 10 : Conditions for AERR submittal to meet o zone p eriodic i nventory r equirement
Condition Comment

Public hearing requirement To the extent it is not practical to coordinate public hearing requirements with an NEI submission and the periodic inventory is not being used for a SIP action with regulatory significance , it may be possible to rely on the EPA ’s guidance to defer the public hearing ( “Public Hearing Requirements for 1 990 Base

- Year Emission Inventories for Ozone and Carbon Monoxide Nonattainment Areas”, September 29, 1992 )

. Annual and summer day emissions must both be submitted for the NAA counties If summer day emissions cannot be extracted from the EIS (as is the case in 2014), using an AERR submission to meet the periodic inventory requirement is only acceptable if approved by the regional office

.

Emissions are submitted for mobile sources. Ongoing review of the AERR may result in requiring mobile mod el inputs and making emissions data optional

. If this occurs, the SIP periodic inventory must still include emissions

. Thus, emissions would need to be submitted for the NAA counties regardless of any AERR requirements to be able to meet the periodic ozone inventory requirement.

Complete

– all sectors Using the AERR to meet the periodic inventory requirement is only possible during triennial years because the EIS only accepts nonpoint and mobile data during these years, and these data categories must be in cluded to be complete. Submitted within 3 years since the base year inventory. It is acceptable to be less than 3 years, after which time the triennial submissions would be every three years. Partial county approach approved by regional office The EIS do es not su pport partial counties

. In some cases, it may be acceptable to use the entire county emissions for the periodicEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

38 Condition Comment submission.
Notification If the AERR approach is approved, the regional office should be notified in writing when the submission has b een completed.

Documentation Must be created

. Submission is at the request of the EPA regional office

.

3.5.2 Regional Haze Current Year Inventory For the R egional H aze R ule, an updated current year inventory is required with each 5

- year progress report or 10

- year SIP revision

. This is a complete statewide annual inventory that follows the requirements of the initial baseline inventory ( included in the original Regional Haze SIP)

. S tates can choose to use the most recent NEI year or anoth er year that can be justified. Since the Regional Haze requirement is an annual period and statewide requirement, it better matches the AERR reporting requirements , and so the AERR inventories can more readily meet the requirement for the current year inventory requirement

. While the triennial AERR years and reporting requirements will match the needs for reporting current year inventories for regional haze, the SIP inventory public hearing requirement will make it extremely challenging for an actual AERR submission (primaril y for NEI purposes) to meet the current year inventory requirement of regional haze SIPs. Notwithstanding this challenge, the c onditions listed in Table 11 provide gui dance to state agencies for using the AERR submittal to meet their current year obligation.

Table 11 : Conditi ons for AERR submittal to meet r egional haze p eriodic i nventory r equirement
Condition Comment

Public hearing requirement The regional haze current year inventory requires a public hearing , and this requirement must be met even when attempting to use the AERR submission to meet this requirement. The EPA expects that it will be very difficult to complete the public hearing req uirement in time for the AERR submission.

Complete

– all sectors Submitting all sectors is only allowed by the EIS in triennial years , and so the year used for a current year inventory would need to be a triennial NEI year. For the submitted data to be us ed, the AERR requirements must be met for point, nonpoint, on

- road mobile, nonroad mobile, and fires. In addition, emissions must be submitted for all sectors even when the AERR allows inputs to be submitted instead of emissions.
Notification If the AERR approach is approved, the regional office should be notified in writing when the submission has been completed.

Documentation Must be created

. Submission is at the request of the EPA regional office

. Regarding the choice of a year, the most recent NEI year will always be sufficient for EPA. However, the year of the inventories for the 5

- year periodic inventories (and 10

- year SIP revisions) are not required toEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

39 be the same as an NEI year

. Using a non

- NEI year will usually occur in cases where another year has been chosen for other reasons, such as a SIP developed for a different NAAQS

. In this case, air agencies should note that it will be easier to justify a newer yea r than the most recent NEI year as opposed to trying to justify an older year

. This is because the purpose of the current year inventory is to provide a current estimate of emissions

. It is presumed that because of ongoing control programs for mobile and stationary sources, which get additional re ductions each year, more current year inventories will reflect more progress towards the goals of emissions reductions in support of the regional haze standards.



### 3.6 Emissions Statement Requirement for SIPs
For ozone NAAs, states should develop emission report ing programs for VOC and NO X sources in accordance with CAA section 182(a)(3)(B). T h e required state program and associated regulation defines how states obtain emissions data directly from facilities and report it to the EPA as part of SIP inventories and for the AERR

. This is called an Emission Statement regulation, and it outlines how facilities must report emissions and facility activity data to an air agency . Once the air agency develops the Emission Statement regulation, the regulation should be sent to the EPA as a SIP for approval

. As an element of a SIP, the public hearing requirements apply to the Emission Statement SIP.
To properly implement the emissions reporting requirements, Emission Statement regulations should be coordinated carefully with t he AERR and any associated guidance and specifications, the Modeling Guidance, and this guidance

. The required and optional data elements needed for inventories (described in Section 2.5.7 ) should be included as fields for reporting to the EPA

. Where the AERR/EIS has required fields, those fields should be required by the Emission Statement regulations.

Additional details o n de veloping emission statement regulations can be found in a dated, but still relevant guidance document entitled “Guidance on the Implementation of an Emission Statement Program (DRAFT)
, ” available at http://www.epa.gov/ttn/chief/eidocs/draft

- implement_jul1992.pdf

. Where data elements to be collected are mentioned, users of that guidance should defer to the paragraph above, explaining that data elements should be coordinated with AE RR/EIS requirements and the recommendations in this guidance for optional fields.



### 3.7 Maintenance Inventories
Maintenance inventories reflect the emissions conditions associated with a NAAQS re designation to attainment following an initial area designation of nonattainment. Thus, the base year for the maintenance inventory should reflect emissions during the time period when attainment was measured. Otherwise, all attributes of the base year inventory apply

. A maintenance inventory is a component of a maintenan ce plan and is therefore submitted to the EPA as a SIP revision

. Thus all guidance for completeness, temporal extent, spatial extent, public hearings, documentation, and summaries appl ies to these inventories.

The on

- road portion of the inventory for the r elevant pollutants and precursors for the last year of the maintenance plan would be the motor vehicle emissions budget(s) that are required for maintenance areas by 40 CFR 93.118(b). States may elect to also establish motor vehicle emissions budgets for t he interim year or years for which they have submitted inventories or for the base year of the maintenanceEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

40 plan. Those decision should be made through the interagency consultation process that is required by CAA section 176(c)(4)(D) and 40 CFR 93.105.

Spec ific additional guidance for maintenance plan SIPs is also available in the memorandum entitled “Maintenance Guidance Document for Certain 8

- hour Ozone Areas Under Section 110(a)(1) of Clean Air Act” (available at http://www.epa.gov/ttn/caaa/t1pgm.html )

. 

### 3.8 Projected Inventories The purpose of the projected inventories is to provide an emissions estimate for a year beyond the base
year

. T hese inventories are a lso called future

- year inventories. T he projected inventories are used for modeled attainment demonstrations and ROP/RFP plan s

. For the modeled attainment demonstration, the projected inventory represents the emissions needed to attain a NAAQS (according to the modeling) in a future year. For the ozone R OP/RFP plan(s) , expected percent reductions of pollutants on specific timetables need to be shown . Calculating expected reductions involves estimation of emissions reductions, w hich can result in a projected inventory that shows the remaining emissions aft er those reductions have occurred.

3.8.1 Attainment Year Projected Inventories As listed in Table 4 , there are two possible attainment year project ion inventories

. The first is the attainment p rojected inventory for the NAA

. The second is the projected inventory for the modeled attainment demonstration , and it is presumed that the requirement for the modeled attainment demonstration also requires this inventory.

As described in Section 3.8.2 , one possible use of the attainment projected inventory for the NAA is for showing emissions reductions associated with an ROP/RFP plan for ozone. While it is conceivably possible to estimate the emissions reductions (rather than future year emissions inventories) required by the ROP/RFP plan, the most common way to estimate the reductions is by creating future

- year inventories and then calculating t he difference between the ROP/RFP baseline and the attainment projected inventories for the NAA.

I n addition , the on

- road mobile portion of the attainment projected inventory for the NAA can serve as the motor vehicle emissions budgets for VOC and NO X . Since these budgets are required for transportation conformity purposes by 40 CFR 93.118(b), such inventories provide a convenient and consistent way to meet that requirement . In this case, the on

- road inventory should be created in accordance with transpo rtation conformity guidance ( http:/www.epa.gov/otaq/stateresources/transconf/ )

. Creating projected inventories includes a large number of data sources and requires estimates for stationary poi nt, nonpoint, on

- road mobile, and nonroad mobile sources

. In addition, some areas may choose to use average fires to represent these highly variable (from year to year) and large contributors to emissions

. B iogenic sources are not generally forecast into t he future because they are so dependent on meteorology

. Section 5 covers the details on projected inven tories

. [PM2.5 Implementation Placeholder]Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

41 3.8.2 Rate of Progress and Reasonable Further Progress Emissions Reductions As described in Section 3.4 and the Proposed Ozone Implementation Rule , Moderate and above NAAs must have a plan for meeting a 15 percent VOC emissions reduction (ROP plan) within 6 years after the NAA designation. Seri ous and above NAAs must also have a plan (RFP plan) to meet a requirement for an additional 3 percent per year VOC reduction (annual RFP) for each 3

- year period after the initial 6 years (after the NAA designation) until the attainment date. In both cases, the VOC reductions can be substituted with NO X reductions when specific conditions apply. Serious and above areas may submit two separate plans since the annual RFP plan is due one year later. Collectively, this guidance calls these plans the ROP/RFP plan (s).
In particular for the ROP requirement, an attainment year projected inventory for the NAA can also meet the ROP requirement by providing a projected inventory that shows the 15 percent VOC (or NO X , as applicable) reductions when compared to the ROP/RF P baseline NAA inventory . For Serious and above areas , an additional projected inventory may be needed to meet the ROP requirement. This is because the ROP requirement at 6 years can be earlier than the expected attainment date. In the case for Serious and above areas , ROP plans cannot use the projected attainment inventory for the NAA, but rather should use an inventory projected at the 6

- year interval.
To estimate the emissions reductions associated with ROP/RFP plans, air agencies should rely on the

same techniques as for other projection purposes, which are described in Section 5

. When these reductions are calculated by creating projected inventories, the on

- road portion of the inventories may also need to follow transportation conformity guidance ( http:/www.epa.gov/otaq/stateresources/transconf/ ) so that it can be used to set the motor vehicle emissio ns budgets.
The emissions projections should include emissions growth where it occurs, emissions reductions intentionally included to meet the reductions needed for ROP/RFP, as well as emissions reductions occurring for other reasons (e.g., as co

- benefits from implementation of other NAAQS and from national mobile source or stationary source rules). These emissions projections will result not only in estimated reductions (which are required to be included in the ROP/RFP plans ) , but also in projected emissions inventories. Thus, the EPA recommends that summaries of these inventories are included in the ROP/RFP plan(s) to communicate the emissions reductions by comparing against the ROP/RFP baseline NAA inventory.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

42 

### 3.9 Public Hearings
Emissions in ventories are considered a part of the SIP under the CAA (see Sections 172(c)(3) and 182(a)(1)(A)); therefore, emissions inventories are required to be included in the public participation associated with SIPs as specified in CAA 110(a)(2)

. Traditionally, state s have submitted their emissions inventories along with other elements of the SIP , and emissions inventories must be approved or disapproved by the EPA under Section 110(k) , including assessing the requirement that it was subject to a public hearing a t the state level

. 18

Additionally, there are policy reasons that support the need for emissions inventories to be approved with the SIP

. Some emissions inventories must be used as a basis for ozone RFP plans for areas classified as Moderate or above

. Additi onally, all NAAs seeking redesignation to attainment will rely on an emissions inventory for purposes of submitting a maintenance plan under Section 175(A)

. B ecause the emissions inventories and projections play such a fundamental role in determining the r eductions necessary to attain and maintain the standard, they need to receive full public scrutiny and be formally incorporated into the SIP.
However, because the regulatory consequences of the inventories are delayed, the EPA believes that it is appropria te to provide a “de minimus” deferral of the state public hearing requirement up to such time as a public hearing is held on the regulatory provisions

. Thus, the EPA recommends that the hearing on the base year NAA inventory be held in conjunction with the hearing on the associated regulatory plan. For areas classified as Moderate or above, the state would need to provide the EPA with verification that a public hearing was held for the emissions inventory no later than the time the state submits an R OP plan , which is due first

. For Marginal ozone NAA , such verification would be due when and if the state submits a maintenance plan for redesignation

. However, to the extent a Marginal area is “bumped

- up” and, therefore, is required to submit a RFP plan, the ve r ification would be due as for M oderate and above areas.
Under this approach, where emissions inventories are used in the development of an ROP/ RFP plan or attainment demonstration, states can defer the public hearing on these inventories until the time th e areas adopt and submit their RFP plans and/or attainment demonstrations that rely on such inventories. The EPA would not take action to approve or disapprove such inventories until the state completes the state public participation process. If a state op ts to submit a consolidated SIP submittal, this should not be an issue

. This approach is consistent with the historical approach taken since 1992, available in

“ Public Hearing Requirements for 1990 Base

- Year Emissions Inventories for Ozone and Carbon Monox ide Nonattainment Areas ” (see http://www.epa.gov/ttn/oarpg/t1/memoranda/o_ei1992.pdf )

.

18 A public hearing must be offered for every SIP submittal but a hearing does not need to actually occur if no one requests a hearing. The detailed requirements for public notice and hearings are given in 40 CFR 51 .102 . See also Attachment B of “Regional Consistency for the Administrative Requirements of State Implementation Plan Submittals and the Use of Letter Notices,” EPA memorandum dated April 6, 2011, from Janet McCabe, Deputy Assistant Administrator for the Offic e of Air & Radiation to the Regional Administrators, www.epa.gov/airquality/urbanair/sipstatus/docs/FINALSIPGuidelinesSubLtrsPN.pdf

.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

43 

### 3.10 Submit Inventory Parts of SIP to the EPA The structure of what the air agency will provide is int egral to the emissions inventory SIP submittal process, since the list of tangible data items and documentation forms the basis of what the EPA will review and ultimately approve for a SIP

. A Microsoft® Word ® format template for air agencies to use for

or ganizing the inventory portion of their SIPs is under development 19

. Table 12 provides the suggested inventory elements of a n Emissions inventory SIP that corresponds to the template and indicates whether they are relevant for ozone, [ PM 2.5 Implementation Placeholder], and/or regional haze SIPs

. Refer to the tables in Section 2.3 for more information on which are required and which are optional

. This section (and Table 12 ) does not include RFP inventories since those are submitted with a separate ROP/ RFP plan

. Similarly, it does not include information needed for a modeling attainment demonst ration submittal to the EPA , with the exception of the inclusion of statewide inventory summaries for ozone and PM 2.5 SIPs for areas that have modeled attainment demonstrations as part of their SIP requirements.

Table 12 : Suggeste d Elements of a n Emissions inventory SIP SIP Planning Inventory Documentation Element Ozone PM 2.5 + Haze Background: Includes key elements explained in this guidance, such as the nature of the air quality problem (or arrival at attainment status for maintenance SIPs), priority source categories and point sources, pollutants covered, spat ial extent, and other key inventory aspects

. Y Y

 Overall Base Year Emissions Summaries: All emissions are for relevant pollutants only

. Data categories would minimally be point, nonpoint, nonroad mobile, and on

- road mobile, though more detailed categories are acceptable

. Biogenic sources and other sources can optionally be included as well, and may be required by regional office s for areas doing modeled attainm ent demonstrations. See Table 13 See

Table 13

 Overall Projected Attainment Year Emissions Summaries: The same

as the base year summaries except using the attainment projected inventory for the NAA. These summaries are optional for the ozone Emissions inventory SIP . For ozone and when developed in accordance with transportation conformity guidance, the on

- road portion also can set the motor vehicle emission budgets for VOC and NO X . If not provided in the Emission Inventor y SIP, the summaries would be needed in the Modeled Attainment Demonstration. S ee Table 13

Stationary Point Sources:

 Introduction with more detailed documentation of the emissions from stationary point sources, including the point source emissions threshold, how the point sources were identified, how emission estimates were made including emission factors, activity data, and control assumptions. Y Y

19 At the time of this d raft, the template is not yet available. It will be a replacement for the “Example Documentation Report for 1990 Base Year Ozone and Carbon Monoxide State Implementation Plan Emissions inventories, March 1992”, located at http://www.epa.gov/ttn/chief/publications.html#general

.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

44 SIP Planning Inventory Documentation Element Ozone PM 2.5 + Haze

 This section includes additional point source emissions summaries

. These summaries should include at a minimum: the county, Agency Facility ID, plant name, physical address, total control efficiency, key control devices, NAICS code, and emissions with and without rule effectiveness applied. The Agency Facility ID or some other ID should be included that can easily map to the EPA facility records in EIS. This can be more difficult when air agencies change their Agency Facility IDs. See Table 14 See

Table 14

Stationary Area (Nonpoint) Sources:

 Introduction with more detailed documentation of the emissions from stationary nonpoint sources, including how the nonpoint sources were identified, the model version used, which sources were not addressed and why, how partial county emissions were estimat ed, and how emission estimates were made including models or tools, emission factors, activity data, and control assumptions. Y Y

 This section includes additional nonpoint source emissions summaries

. For county and emissions processes reported that have reductions associated with rules, these summaries should include any control efficiencies or rule effectiveness assumed and emissions with and without rule effectiveness applied. Projected attainment ye ar emissions summaries may also be required for areas performing modeled attainment demonstrations. See Table 15 See

Table 15

Nonroad Mobile Sources

 Introduction with more detailed documentation of the emissions from nonroad mobile sources, including now the nonroad mobile

sources were identified, which sources were not addressed and why, how partial county emissions were estimated, and how emissions estimates were made including model version , source of input data, input and output data files, and any post

- processing methods used to dev elop the inventory

. Y Y

 This section includes additional nonroad source emissions summaries. Projected attainment year emissions summaries may also be required for areas performing modeled attainment demonstrations. See Table 15 See

Table 15

On

- road Mobile Sources

 Introduction with more detailed documentation of the emissions from on

- road mobile sources, the model and version used, how partial county emissions were estimated, and how emissions estimates were made including sources of input data, input and output data files, and any post

- processing methods used to develop the inventory

. Y Y

 This section includes additional on

- road source emissions summaries. Projected attainment year emissions summaries may also be required for areas performing modeled attainment demonstrations. See Table 15 See

Table 15Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

45 SIP Planning Inventory Documentation Element Ozone PM 2.5 + Haze Other Sources

 A description of other sources in the emissions inventory not included in the planning inventories and reasons why they are not included. Y Y

 This section includes summaries, if available, of other sources of emissions

. Projected attainment year emissions summaries may also be required for areas performing modeled attainment demonstrations. See Table 15 See

Table 15 Demonstration of Public Hearing: A brief description of the public hearing process, a summary of the results, and any other relevant materials

. The purpose of this section is to provide evidence for the public hearing and what the air agency learned through the process.

+ PM 2.5 is included here only as a placeholder for subsequent versions of this guidance.

Table 13 provides the summaries to include in the background section

. In the table, “data category” is consistent with the definition provided in Table 12 and Section 2.5.1

. If both the base year inventory and the attainment projected inventory are included in the background, then the same summaries should generally be provided for both.

Table 13 : Summaries to include in the background
Emissions Summaries Ozone PM 2.5 + Haze Emissions for the state by data category Y ‡ Y Annual base year emissions for the state by county and data category Y ‡ Y Annual base year emissions for the NAA by data category Y Annual base year emissions for the NAA b y data category and county ( or partial county) ∆ Y

Summer day base year emissions for the NAA by data category Y Summer day base year emissions for the NAA by data category and county (or partial county) λ Y

+ PM 2.5 is included here only as a placeholder for subsequent versions of this guidance. ‡ For SIPs that include air quality modeling, this section can include both summaries of the planning and the modeling inventories

. Since modeling domains are usually much larger, multi

- state areas, the resolution of the modeling inventory summaries depends on the modeling guidance and the preferences of the regional office

. One option is to include county

level detail for the state(s) included in the NAA , but state

- level detail for surrounding states.
∆ Providing both the county and partial county could provide more flexibility for states when submitting periodic inventories. λ Partial county emissions can be included rather than, or i n addition to, full county, where applicable.

Table 14 provides the minimal requirements for summaries to include in the point sources section

. If both the base year inventory and attainment projected inventory are included in the background, then the same summaries should generally be provided for both.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

46 Table 14 : Summaries to include in the point sources section
Emissions Summaries Ozone PM 2.5 + Haze Annual base year emissions for each point source as a facility total, within the state. Y

Annual base year emissions for each point source as a facility total, within the NAA

. Y

Summer day base year emissions for each point source as a facility total, within the NAA

. Y

+ PM 2.5 is included here only as a placeholder for subsequent versions of this guidance.

Table 15 provides the minimal requirements for summaries to include in the nonpoint and mobile sources sections

. If both the base year inventory and the attainment projected inventory are included in the background, then the same summaries should generally be provided for both

.

Table 15 : Summaries to include in the nonpoint and mobile sources sections
Emissions Summaries Ozone PM 2.5 + Haze Annual base year emissions by county and SCC (or SCC group ‡ ), within the state. Y Annual base year emissions by county and SCC (or SCC group), within the NAA

. Y Summer day base year emissions by county and SCC (or SCC group), within the NAA

. Y

+ PM 2.5 is included here only as a placeholder for subsequent versions of this guidance. ‡ See additional information below on SCC groups

. SCC groups for on

- road and nonroad mobile sources can be useful in limiting size of summaries without much loss of informati on

. For example, SCC groups can be formed for grouping by vehicle type and fuel, dropping the road classifications

. Vehicle types can be further grouped into light duty and heavy duty

. The amount of grouping appropriate depends on what a particular summary and SIP are trying to communicat e

. SCC groups can be suggested as appro priate by regional offices or air agencies as part of the consultation for what will be included in the emissions inventory SIP.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

47 

## 4 Developing Current Emissions inventories
This section covers the decisions that states will need to make regarding any “current” emissions inventory, including a base year NAA or state inventory, RFP baseline inventory, periodic inventory (for

ozone or regional haze ), or maintenance inventory

. As a reminder, all inventories described in this section are inventories of actual emissions; these inventories do not contain emissions based on potential to emit nor allowable emissions.



### 4.1 Inventory Years A fundamental step in creating a base year inventory is the choice of inventory year

. The Ozone, PM 2.5 and R egional H aze I mplementation R ules include specific language regarding the choice of inventory years, and those regulatory requirements supersede any guidance provided in this section

. Since the purpose of the base year inventory is to represent relatively current emissions conditions, there is a general preference for using as recent a year as practical

. T his means that the year of emissions estimates is usually several years earlier than the year in which the inven tory work is done , given the time that it takes to compile an emissions inventory (for example, an inventory with 2014 emissions may not be compiled until 2016)

.
Ozone The prima ry considerations in choosing a baseline inventory year as c overed in this guid ance are (1) the implementation rule requirements, (2) the appropriateness for use as an ROP/RFP baseline year, and ( 3 ) the availability of data

. This is in contrast to inventories used for air quality modeling, for which meteorology , and availability of a mbient data are the primary considerations , with inventory availability secondary

. This is because the meteorological conditions selected should be associated with ozone formation that is representative of either the ambient data relied upon for designation to nonattainment or recent ambient data, as appropriate. C hoosing a year based solely on inventory availability could result in choosing an inappropriate year (considering ambient measurements and the meteorology that led to those measured conc entrations)

. As a result, the base year(s) used in the planning inventories can be different than the modeling base year and associated modeling inventory.

The consideration of the i mplementation rule requirements means that the inventory base year should be one of the three years of ambient data used for designation of the NAA or another applicable year as described in the implementation rules and here

. The idea behind this connection is that the inventory should represent the emissions conditions in the l ocal area associated with the nonattainment problem

. Given this purpose, situations may arise where the most applicable available inventory is not one of these three ambient

- data years

. Two examples of such situations are offered here

. In the first case, a newer inventory may be advisable. Because of time that it takes for designations to occur and the period allowed for SIP submittal, a significant increase in emissions could occur between the designation period and the time SIPs are submitted

. This has o ccurred in some areas due to oil and gas development, for example

. In these cases, it may be more appropriate to use an inventory year that is newer than one of the three years of dataEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

48 used for designations , to represent the higher emissions or different s ource mix associated with a more current year

. Another example is that in an area where mobile sources are a small part of the emissions inventory, emissions may not have changed much from a year prior to the three

- year period of ambient data

. In this case , an available inventory prior to one of the three years may sufficiently represent the inventory

. In both cases, the air agency preparing the SIP should explain these issues as part of its justification for not using one of the three years.

The considerat ion of the appropriateness for the ROP/RFP baseline year means that states should consider that that base year will be the same for the ROP/RFP baseline. In general, states will select a year within the three year period associated with the ambient data us ed to make the nonattainment designation. Within this time period, a large source of emissions may be reduced. If a state chooses a year after those reductions have occurred, then the state would not get the benefit of those reductions in meeting their ROP /RFP requirements. In addition if those emissions were a key part of the nonattainment problem, then the choice of the later year would not follow the guidance that the year selected be representative of the conditions leading to nonattainment.
Lastly, t he consideration of “availability” is simply what data are (or will be) available to the air agency during the time alloted for SIP preparation

. Often, the triennial NEI year inventories ( as described above ) are useful starting points for meeting the various “current” inventory requirements associated with SIPs

. For these triennial NEI years, states are already required to have prepared and provided to the EPA complete inventories of criteria pollutants and precursors important for ozone, PM 2.5 , and regional haze SIPs

. Other inventories may also be available, for example, one that was developed to meet planning requirements for one NAAQS may be a useful starting point for the inventory for a planning requirement for a different NAAQS

. A secondary benefit of us ing an NEI year is that NEI data are available for all
states , and information from more than one state may be needed for attainment demonstration modeling purposes. Additionally, other data needed for modeling (e.g., meteorology and SMOKE inputs)

are more likely to be available from the for the triennial NEI years.
Regional Haze

The R egional H aze R ule includes both a baseline inventory requirement and a current year inventory requirement

. Under 40 CFR 51. 308(d)(3)(iii), the rule states that “The baseline e missions inventory year is presumed to be the most recent year of the consolidate [sic] periodic emissions inventory.” For the initial regional haze SIPs , the year used should have fallen between and inclusive of the 2000 to 2004 baseline period. M ost area s used 2002 as their baseline inventory year in their initial SIPs based on an OAQPS memo about this issue (see http://www.epa.gov/t tn/naaqs/aqmguide/collection/cp2/ 20021118_wegman_2002_base_year_emission_sip_planning.pdf ).
Also for regional haze , an updated current year inventory is required with ea ch 5

- year progress report or 10

- year SIP revision

. In both cases, states can choose to use the most recent NEI year (the “presumption” of the rule) or another yea r that can be justified

. In general, it will be easier to justify a newer year than the most recent NEI year than an older year , since the purpos e of the updated current year inventory is to provide a n estimate of emissions for the most recent year possible

. It is presumed that because of ongoing control programs for mobile and stationary sources, which get additionalEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

49 reductions each year, more rec ent year inventories will reflect more progress towards the goals of emissions reductions in support of the regional haze goals

. 

### 4.2 Pollutants and Pollutant Precursors to Include in Inventories This section describes the pollutants and precursors that should be includ ed in the planning inventories for the ozone, PM 2.5 , and regional haze rules

. Pollutants for ROP/RFP inventories are also described in Section 3.4.2

. Beca use many sources emit more than one of the precursor pollutants, and because the precursor pollutants have the potential to be transported across state boundaries, EPA encourages air agencies to develop inventories fo r all pollutants where possible to supp ort integrated, regional

- scale modeling, and control strategy development for ozone, PM 2.5 , and regional haze.

The CAA 172(c)(3) requires “the relevant pollutant or pollutants” to be included in inventories for SIPs

. The ozone, PM 2.5 and regional haze implementation rules include specific language regarding the pollutants and precursors to be included, and those regulatory requirements supersede any guidance provided in this section.

For the 8

- hour ozone NAAQS, the pollutants to be i nventoried are VOC, NO X , and CO. For ROP/RFP baseline NAA inventory for ozone, only VOC and NO X should be included (though CO could also be included in the same inventory if it also serves as the attainment projected inventory for the NAA). For regional haze, the pollutants to be inventoried include all of the pollutants and precursor pollutants identified for ozone and PM 2.5 , except for CO.
[PM2.5 Implementation P laceh older]

4.2.1 Condensable PM emissions [PM 2.5 Implementation Placeholder]

Table 16 : Source types e xpected to include condensable PM +

EIS Sectors (and subsectors) Subsectors and Degree of Condens a ble Data

Categories

+ This table is included as a placeholder pending the addition of PM2.5 to this draft guidance.

4.2.2 Regulatory D efinition of VOC The EPA’s current regulatory def inition of VOC (40 CFR 51.100 (s) ) excludes constituents considered to be negligibly reactive in atmospheric photochemistry

. These include methane, ethane, methylene chloride, 1,1,1

- trichloroethane (TCA), several Freon compounds, acetone, perchloroethylene, and others . States sho uld use the CFR reference above to find the complete list. Over time, additional compounds may be exempted from this VOC definition

. The exempt compounds are considered negligibly reactive, although some can influence the formation of ozone when present in sufficient amounts; for example, methane impacts on ozone ha ve been observed in areas of high methane emissions associated with oil and gas development

. The emission factors used to estimate organic emissions generally account for nonmethane hydrocarbons (NMHCs)

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50 For SIP purposes, state , local and tribal agencies should report VOC as defined by the EPA (40 CFR 51.100 (s) )

. This is the case regardless of the treatment of methane for modeling inventories, which is addressed in more detail in the next subsect ion.

4.2.3 Treatment of M ethane The treatment of methane in emissions inventories may be relevant for emissions used in modeled attainment demonstrations. Methane is not expected in other planning inventories associated with SIP s

. This section is included in thi s guidance, however, to explain the context for which methane emissions can be important and to specifically note its possible relationship to the VOC emissions that are associated with SIP planning inventories. In some cases, air agencies interested in co nsidering non

- VOC

based estimates of methane in their modeling inventories may optionally choose to consider methane as part of non

- modeling inventories as well.
The air quality models used for modeled attainment demonstrations use methane as one of the

mo deled pollutants . However, these models have typically used a fixed concentration of methane that does not change. Thus, typical applications have not used methane emissions from emissions inventories.
Unlike the air quality models, the emissions processin g steps to prepare emissions inventories for use in air quality models do compute methane emissions

. M ethane has traditionally be en calculated by applying a factor to the VOC emissions to calculate total organic gases (TOG)

. These TOG emissions are then sp lit during emissions processing into “model species,” which include methane

. With the low reactivity of methane and the absence of its use in air quality modeling for ozone, the VOC

- to

- TOG factors and the methane part of the speciation factors were not giv en much scrutiny

. Previous versions of this guidance encouraged inventory developers to simply use the default VOC

- to

- TOG factors that were associated with the speciation profiles without further analysis, since the methane emissions were not used

. This approach may still be appropriate for most or all NAAs for their modeled attainment demonstration.
In limited situations, air agencies may want to inv estigate the extent that methane emissions pl ay a role in ozone episodes . Hence , additional efforts go ing beyond the us e of the default VOC

- to

- TOG profiles and default methane fractions from the speciation profiles may develop over time

. In this case, i t may be of interest to include methane emissions inputs to air quality models to achieve sufficient model
pe rformance for a modeled attainment demonstration

. Approaches can include incorporating methane emissions from other sources into emissions inventories used for modeled air quality

. For example, the MOVES model estimates methane emissions directly, so there would be no need to use VOC speciation to estimate those emissions. Air agencies considering methane as a contributing factor should c onsult with their EPA regional office to discuss the best sources for such data as this inventory development area is und ergoing many changes at this time

. Furthermore, more specific VOC

- to

- TOG factors and speciation profiles may be useful, particularly for analysis related to areas of very high methane emissions

. These issues are all associated with modeled attainment demon strations, and do not affect the VOC emissions reported as part of the emissions inventory SIP.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

51 

### 4.3 Identification of Priority Sources
T he Proposed Ozone Implementation Rule and previous PM 2.5 I mplementation R ule refer to the AERR requirement s for creating th e inventories used for SIP s

. This includes the AERR requirement that inventories must include all sources of emissions

. Thus , inventories used for SIPs are expected to be complete, with emissions from all sources (other than de minimus sources ) characterized in some way. In addition to better understood and routine emissions sources, emissions from known or quantifiable fugitive sources such as leaking tanks or valves should be included in inventories when these emissions can be quantified in bo th the base and future years and because their reductions could help in achieving
att ainment. These emissions should not be excluded based on an invalid assumption that they are “malfunctions”. In addition, startup/shutdown emissions should be included in inventories (see Secti on 4.8.1 )

. While completeness is required, t here is no requirement that all parts of an emissions inventory be completed with the same degree of rigor

. Because emissions inventory development is time consuming and expensive , it is wise for inventory developers to focus their resources on the sources of emissions making up the bulk of the pollutants relevant for the NAAQS in question

. To the exte nt that an inventory is to be used for multiple NAAQS or for multi

- pollutant analysis, then the larger sources important for all relevant pollutants should be characterized with as much technical rigor as is feasible.
Fortunately, existing inventories can help states guide their initial understanding of the sources of pollutants in a particular area

. Air agencies can rely on the latest NEI or previously compiled SIP inventories to guide further development

. The NEI is commonly used as a starting point for state and regional planning purposes for NAAQS implementation and regional haze planning. The EIS can help by providing emissions summaries for counties or groups of counties and for emissions sectors or SCCs.
For additional information, the Particulate Emissions volume of the EIIP technical report (see http://www.epa.gov/ttn/chief/eiip/techreport/ ) provides thorough recommendations for identifying

sour ces of PM emissions

. These recommendations can be useful for other pollutants as well.
Starting with an existing inventory poses some risks and challenges

. Here we try to address the most common issues associated with SIP inventories when starting with exi sting inventories:

1. How do I know which sources in an existing inventory should get further review ? The EPA suggests the following considerations in deciding which sources to be reviewed:

a. The largest contributors to the pollutants of interest (i.e., the pol lutants contributing to ozone and/or PM 2.5 formation) using some coarse groupings, such as the EIS S ectors, Tier 2, or Tier 3 groups

. b. Sources within the NAA (or contributing to it in the case of modeling attainment demonstration inventories) . Special cons iderations to sources closest to and upwind of violating monitors may deserve special attention.

c. Knowledge about the growth or retraction of a particular sector of the economy. Oil and gas production is a recent example of a quickly growing industrial sour ce of emissions.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

52 d. Considering whether the proportion of emissions associated with a particular source is likely to have an impact on the outcome of decisions

. Emissions methods/changes for sectors that are likely to have a large impact on the planning pr ocess should get higher priority.

e. Assessing whether the approaches used in the preparation of SIP emissions are updated with current approaches, including appropriate emission factors. This is particularly important for source categories for which there is large uncertainty and those with ongoing research.

2. What if the original inventory does not use good approaches? The EPA recommends starting with inventories that have available and clear documentation

. If an inventory developer cannot figure out how the emissions were estimated, t hen it will be difficult to build upon those results

.
With documentation, inventory developers should be able to evaluate the quality of approaches used

. As part of the NEI program, the EPA publishes updated methods for many no npoint emissions categories

. The highest quality p oint source emission s estimates are based on facility

specific testing, and where not available, current emission factors

. Mobile emissions should be ba sed on the latest mobile models, using as many locatio n

- specific inputs as possible.

If it is determined that a starting inventory does not use the latest methods, it is advisable to reassess those emissions with newer methods (or other available inventories) prior to deciding if that category requires even further work.

3. If I need to make updates, w here are the latest approaches available? The EPA’s NEI program is a good source of the latest approaches and approaches in development

. In many cases, m ulti

- jurisdictional organizations also have updated approach es for various emissions sectors

. The Emissions Inventory Improvement Program volumes still have a lot of valuable information on emissions, though some sections are outdated (see http://www.epa.g ov/ttn/chief/eiip/techreport/ )

. Approaches have historically included AP

- 42 and WebFire emission factors, though these resources are out date d for some sectors

. For more information on updated emission factors, see Section 4.6

.

4. What do I do if the NEI approach has added PM or other emissions that I did not report, and I think that they are invalid? The EPA commonly augments PM emissions provided by states in the NEI because many states do not report total PM 2.5 and neglect the condensable portion of PM emissions (see also Section 4.2.1 )

. Consistent with the requirements for co mplete SIP inventories, the EPA works to create a complete and accurate NEI

. If emissions have been added erroneously, states should make those improvements, but should also let the NEI program staff know that there may be a flaw in their methods and provi de a better source of information

. Just because a source has not reported condensable emissions does not mean that they do not exist or should not have beenEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

53 characterized

. In some cases, states may need to go back to sources to clarify that condensable PM emissions must be provide d to the state agencies.

Another source for added EPA criteria pollutant and precursor emissions is NH 3 for point sources from the TRI

. Since these are emissions that the facility submits to the EPA through the TRI program, they s hould potentially be included in SIP inventories for PM 2.5 SIPs and ideally included in inventories provided to the EPA (as a point or nonpoint source)

. If a state air agency believes that these emissions are erroneous or unimportant, some discussion of th ese sources should be included in their SIP as to why the TRI emissions are not being used

. For incorrect emissions, states should consider coordinating with the facility to improve the emission estimates.



### 4.4 Spatial Extent The spatial extent of an inventory refers to counties, states, or other geographic regions c overed by the emissions data

. As described in previous s ections, inventories needing to be included in SIPs are either for the NAA area only (for ozone and PM 2.5 ) or are for the entire state (for re gional haze and ozone or PM 2.5 when modeled attainment demonstrations are needed). Modeled attainment demonstrations use emissions from a regional multi

- state area. While It is not a SIP requirement to submit an inventory for other states, the emissions ar e needed to do the modeling.

A number of complicating issues related to spatial extent arise with inventories

. Below, more information is provided on partial counties, when point

- source locations are needed for emissions that have traditionally been nonpoi nt sources, shapefile

- based inventories, and link

- based mobile emissions.

4.4.1 Nonattainment A reas with Partial Counties In some cases, NAAs do not follow county boundaries

. Since most inventories and many underlying datasets are available at the county level, this poses a challenge for emissions calculations, in particular for nonroad and mobile sources.

A ir agencies may wish to use full

- county emissions in meeting some SIP requirements, despite the designation of partial

- county NAAs. The EPA has considered the advisability of using whole

- county emissions to represent partial county emissions and has determined that this is not possible. In particular, using whole

- county emissions would po se a challenge for using these inventories for ROP/RFP analyses , which can only include reductions within the NAA

. Thus, areas designated as partial counties should estimate those partial county emissions using one of the approaches described here.

For point sources, Geographic Information System ( GIS ) technology enables straigh tforward select ion of point sources into a partial

- county NAA by intersecting a dataset of point source latitude/longitude coordinates with a shapefile of the NAA boundaries.
For nonpoint and mobile sources, available inventories and methods are often designed to create county totals, making partial counties much more difficult

. A variety of acceptable approaches exist forEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

54 calcula ting partial county emissions, though the particular approaches chosen should be agreed to as part of developing the plan for the SIP planning inventory as described in Section 2.2

.
1. Custom calculations : Air agencies could develop a custom approach to estimate emissions using activity data estimated for the partial county area

. Since many source categories need to be
est imated, this could be a very labor intensive approach, or could be used for just key categories where other approaches are insufficient.

2. Shapefile

- based inventories : See Section 4.4.3

.
3. Use of spatial allocation surrogates : Some sources of data exist at sub

- county resolution, including road networks, travel demand model results (see also Section 4.4.4 ) , and census data that are available at census tracts or blocks

. When the emis sions activity can be reasonably assumed to follow an allocation method based on one such surrogate dataset, GIS techniques can be followed to apportio n a county emissions estimate to a partial county NAA based on the patterns of these sub

- county data.

4. Use of gridded modeling data : Modeled attainment demonstrations rely on air quality modeling that uses gridded emissions data, which could be resolved at a sub

- county resolution

. Gridding resolutions of 12

- km, 4

- km, or even 1

- km have been used

. Similar to what was described ab ove in the previous approach, emissions processing relies on spatial surrogates to apportion county

level data to grid cells needed f or modeling

. Rather than take a custom spatial surrogate approach, these gridded data may be sufficient to apportion county

- level data to a partial

county N AA using GIS overlay techniques

. Such an approach would sum the parts of the gridded data intersecti ng the partial county area to provide the partial county area inventory

. The primary difference in this approach compared to the previous approach is the intermediat e step of using the gridded data

. This co uld be appealing since those gridded data may alre ady be available from modeling done for attainment demonstrations

.

5. Expert judgment : When there is no appropriate sub

- county data surrogate available, when air quality modeling is not part of the SIP process, or when a category is relatively unimportant to the SIP planning process, other methods may be advisable

. In this case, an air agency should explain their rational to the respective EPA regional office and come to agreement on a technically reasonable approach

. Such approaches could include using the entire county estimated emissions, assuming some fraction based on understanding of county activities, or taking a area

- proportional (uniform distribution) approach

. In this latter approach, the partial county emissions are assumed to be the total county e missions times the area of the partial county divided by the area of the total county.

Since these partial county emissions calculations could need to be done for a variety of inventories and for SIP revisions, considerations should be made for the repeata bility of the approach so that it does not become overwhelming to the analysis

. In collaboration with the EPA regional office , a balance needs to be found among level of effort, technical credibility, and repeatability.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

55 The latest EPA spatial allocation da ta are available on the Emissions Modeling Clearinghouse (EMCH) Spatial Allocation website. The latest spatial approaches and data are also available with the latest emissions modeling platform data on the EMCH main page

. The EIIP Volume III, Chapter 1 , Section 4.3 provides some additional information on spatial allocation ; h owever, the examples used for spatial allocation approaches are much too old for most applications , and more sophisticated spatial surrogate approaches are available than those given as examples

. In particular, except in rare circumstances, the use of population data as an allocation method is outdated and not recommended

.
4.4.2 Point Source L ocations Needed for Modeling of T raditional Nonpoint S ources In some cases, the details needed in a modeled attainment demonstration push inventory developers to use point

- source locations for source categories that have traditionally been n onpoint sources

. Some examples include sources of agricultural ammonia, dry cleaners, and gas stations

. Rather than creating a much larger point source inventory, one approach is to keep a source as nonpoint, but use an emissions processing technique for m odeling known as area

- to

- point allocation.
While this topic is primarily one for consideration in modeling inventories, it is include d here because the planning inventory often provides a starting point for the modeling inventory (for the NAA counties). To the extent that modeling needs can drive additional detail in the planning inventories, this area

- to

point feature can allow small so urces to be included as nonpoint sources in a planning inventory but still allow point source locations to be used for modeling.

In area

- to

- point allocation, the emissions processor for modeling starts with county

- wide estimates and

a user

- provided dataset that allocates county wide emissions to discrete latitude/longitude points (within the county)

. The inventory developer still must obtain the point source locations and proportion of countywide emissions, but the point source inventory remains more focuse d on the largest sources

. Using an area

- to

- point allocation approach also avoids having to define stack parameters for inclusion of small sources in the point source inventory, which is useful because the stack parameters are not necessarily relevant to or available for these source categories.

4.4.3 Shapefile

- based I nventories The EPA collects inventories for the NEI for commercial marine and locomotives using GIS shapefile

based inventories

. Rather than including emissions as a county total, the emissions are a llocated to individual sub

- county areas or lines, each with its own GIS polygon shape

. This approach was developed primarily to support fine scale and risk modeling that are done at a scale finer than most mode led attainment demonstrations.

T hese inventori es can be useful for computing partial county emissions for those categories using this approach

. Otherwise, it may not be necessary to start with the shapefile

- based inventories for SIP planning, except in circumstances where the CMV and locomotive emissi ons spatial distribution is critical to the modeled attainment demonstration in some way

. This may be important in NAAs that contain large ports and/or are near major coastal or inland waterways.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

56 4.4.4 Link

- based On

- road Mobile E missions and Travel Demand M odels SIP inventories often put great focus on mobile sources through the use of detailed emissions by roadway segments (or links) and the use of travel demand models (TDMs)

. This possibility is simply mentioned here for completeness and is not necessarily reco mmended, since thes e efforts are often substantial. The approach can also help with partial county emissions estimates

. 

### 4.5 Temporal Basis Various temporal bases may be needed for meeting different inventory requirements for SIPs. These can be different for o zone, PM 2.5 , and regional haze.

For ozone SIPs, summer day emissions (as defined in Section 2.5.2 ) are used for the base year inventory for the NAA

. Additionally, for areas including modeled attainment demonstrations in their SIP, statewide

ozone summer day emissions and statewide annual emissions may also be important for regional office evaluation and approval of the SIP

.
Summer day emissions are as defined in Section 2.5.2 and in the AERR 20 . These emissions should be representative of the conditions leading to nonattainment, as recommended by the air agency and approved by the EPA prior to computing emissions

. In instances where ozone values are elevated above the level of the NAAQS only in non

- summer months or on weekend days, including whe n winter emissions or weekend emissions dominate the episode, the goal o f representativeness and the purpose behind the definition may support using those emissions instead of limiting the data to “summer” or

“ weekday ” emissions.

To calculate summer day emissions, reporting agencies should estimate emissions for a specific per iod (month, week, selected days, or a day) where emissions (and other factors) resulted in ozone values above the level of the NAAQS leading to nonattainment

. The preference should be given for weekdays as previously described, unless there is a reason to use other days

. A summer day emissions value should be calculated by summing the emissions on those days and divid ing by the number of days included in the sum

. Mobile source emissions models can produce output for an average summer weekday or weekend day. Consult the EPA ’s MOVES Technical Guidance for details ( http://www.epa.gov/otaq/models/moves/index.htm#sip ).
As noted in the preamble for the Proposed Ozone Imple mentation Rule, HEDD periods could have higher emissions than during other periods that could contribute to ozone formation in a particular nonattainment area

. Additional contributing factors to HEDD

- period impacts include location and timing of the HEDD

- r elated emissions, emissions amounts from other sources during the HEDD period, and meteorology. If an air agency determines that emissions increases ( within a NAA ) associated with HEDD periods significant ly contribute to ozone nonattainment, then the air a gency should include those higher emissions in the planning inventories : the base year inventory for the NAA (which also serves as the

20 The EPA notes that this definition has been proposed to be removed from the AERR along with the removal of the requirement to report summer day emissions to EIS. The EPA recognizes the continued need to include the requirement to submit such emissions for the purposes of ozone implementation as well as the need to provide a regulatory definition in other portions of the CFR.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

57 ROP/RFP baseline) and the attainment projected inventory for the NAA

. As described above, in consultation with the EPA re gional office, air agencies select periods to use for defining the appropriate days to include in the calculation of s ummer day emissions that are representative of the conditions leading to nonattainment. Thus, air agencies that have determined HEDD perio ds are important should select such periods as part of their summer day emissions estimation approach. As a result, air agencies could estimate HEDD emissions in a way that represents an appropriate portion of their NAA emissions inventories. More informat ion on how to estimate HEDD

- related emissions is provided in Section 4.8.1

. [ PM 2.5 I mplementation P laceholder]
The temporal basis for emissions in regional haze SIPs is always annual actual emissions.



### 4.6 Emission Factors for SIP Emissions Inventories Emission factors for SIP development should come from credible source s. T he possible sources necessarily differ for stationary, on

- road mobile, and nonroad sources

. The mobile sources with EPA models are the most straightforward . For all states but California , on

- road mobile emissions should be estimated with the latest EPA on

- road model, MOVES. For California, the most recent EPA

- approved version of EMFAC should be used. For stationary sources and remaining nonroad mobile categories , there are several approaches that can be acceptable, with the guiding principle of using credible sources of data

. Where emissions inventory SIPs are to be approved by the EPA , inventory deve lopers should work with the appropriate EPA regional office to make sure the emission factors are acceptable

.
Air agencies should pay close attention to the methods that they are using to calculate emissions to ensure updated approaches are used

. It would be difficult for an EPA regional office to approve an inventory that used an outdated method for an important part of the inventory if an updated method was available at the start of the SIP planning inventory development effort

. Since the EPA could have multiple approaches posted for the same sector and some of those approaches could be outd ated, air agencies should not assume that all EPA

- posted methods are equivalent and acceptable

. For example, some emission factors from AP

- 42 for nonpoint sources are outdated when compared to nonpoint methods and factors used for the NEI. The EPA recommends that air agencies refer to the latest NEI development web pages and contact regional offices to confirm that their planned approaches are up to date

. Th e IPP process described above can be helpful in this process.
For most stationary point sources, air agencies have rules in place that require the submission of point source data to the state for air planning purposes

. Much of these data are then submitted to the EPA as part of the NEI and used as the basis for point source inventories in SIPs

. These state rules may have their own requirements about emission factors and source tests to be used; where possible, these rules should follow this guidance.

The EP A recommends selecting emission factors based on the hierarchy of emission factor sources shown in Table 17

. T he higher up on this hierarchy the emission factor chosen , the better the quality of the emissions estimate

. Based on the emission factor approach used, the states should also set the required “emission calculation method code” (see Section 2.5.14 ) for inclusion in their inventory data

.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

58 Other approaches that do not require emissions factors (e.g., CEMS, materials balance, engineering judgement).

Table 17 : Hierarchy of emission factors for use in po int source emissions inventories

Rank Emission Factor Approach E mission factor method code to use 1 Continuous emissions monitoring system 1

2 Facility/process

- specific emission factor

. Average of representative stack tests (on one stack) downstream of controls (or if no controls) 4

3 Single representative facility/process

- specific stack test downstream of controls (or if no controls) 4

4 Facility/process

- specific uncontrolled emission factor, plus control efficiency

. Average of represen tative stack tests (on one stack) upstream of controls, adjusted based on expected control efficiency. 24

5 Single representative facility/process

- specific stack test upstream of controls, adjusted based on expected control efficiency 24

6 Site

- specific emission factor

. Average of representative stack tests across multiple stacks or processes, downstream of controls (or if no controls) 10

7 Site

- specific uncontrolled emission factor, plus control efficiency

. Average of representative stack tests across m ultiple stacks or processes, upstream of controls, adjusted based on expected control efficiency

. Only makes sense when all processes measured are fed to the same type/combination of control devices. 30

8 Material balance 3 9 Manufacturer specification 7

10 Best available other emission factor for uncontrolled or including controls, which is one of: EPA emission factor 8 S/L/T emission factor 9 Vendor emission factor 11 Trade group emission factor 12 Other emission factor 13

11 Best available pre

- control emission factor, plus control efficiency , which is one of: EPA emission factor, plus control efficiency 28 S/L/T emission factor, plus control efficiency 29 Vendor emission factor, plus control efficiency 31 Trade group emission factor, plus control efficiency 32 Other emission factor, plus control efficiency 33 1 2 Engineering judgement 2

13 Emission factor with best available speciation profile, one of:

EPA speciation profile 5 S/L/T speciation profile

– e.g., to calculate metals emissions from filterable PM 2.5 or volatile HAP from VOC. 6Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

59 

### 4.7 Inventory Data Codes Building inventories includes the use of various codes , such as SCCs, state/county FIPS, tribal , control measure, NAICS , pollutant and emission method codes

. A full accounting of all possible codes is available as part of the EIS “Reporting Code Tables,” which are available to EIS users using the “Reporting Code Tables” link at the left hand side and are available to non

- EIS users (on a somewhat

m ore delayed timetable) at http://www.epa.gov/ttn/chief/ eiinformation.html under “EIS Code Tables

. ” There are more than 60 separate lists of codes that define all of the required and optional co ded data el ements based on the AERR

. As we have noted above, the AERR is relevant as the rule that codifies the correct development of all inventories submitted to the EPA

.
4.7.1 Codes to U se for Nonattainment Area I nventories Air agencies developing inventories for SIP planning should use valid EIS codes in all of their inventories

. Since codes change over time, the EPA has adopted the approach in the EIS to “reti re” codes when no longer needed and to add codes when needed

. Codes are generally retired in coordin ation with NEI development cycles, ideally retiring codes only when plenty of notice has been provided to states in advance of an NEI inventory submission period

. As such, codes that are retired may have already been used as part of a SIP development proce ss, and that is okay. This is the advantage to retiring codes rather than removing them

. Conversely, the EPA may not be able to retire a code until an appropriate point in the triennial NEI cycle

. If an air agency wishes to submit a SIP

- related inventory to the EIS for the NEI or another purpose, it will need to use valid (and not retired) codes for the year being submitted.

4.7.2 How to R equest New Codes or Code R etirements In general, if a new code is needed for compiling an inventory, then a n air agency staff member should
contact the EPA to request a new code

. The recommended contact method is to use the call or email using the contact information listed for “Facility Inventory and Point Emissions” on the EIS contacts page
at http://www.epa.gov/ttn/chief/eis/index

. Requests for codes should include which code table(s) are affected, why existing codes are not sufficient, and a recommendation for a cod e and its definition and
purpose

. While the EPA anticipates that code retirement requests will usually come from the EPA rather than from external groups, a code retirement request should be made using the same mechanisms.

The EPA most often gets requests for new SCC codes since new emissions processes arise in industries, or processes are newly identified as having emissions associated with them

. If an air agency inventory developer cannot find an appropriate SCC c ode for an inventory process, a choice nee ds to be made to either use a generic (“miscellaneous”) SCC or to request a new SCC

. For cases in which the contribution of the emissions process to any one precursor pollutant is minimal, inventory developers may choose to report using one of the miscellaneous SCCs

. If the process is a significant source of one or more pollutants or that process might be a part of a control program, then an SCC request is probably warranted . The EPA staff will evaluate the SCC request to make sure that a similar co de does not alreadyEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

60 exist, consider codes that have been created but not yet activated for use in submitted inventories 21

, assess the need for the SCC, and either indicate an existing appropriate SCC to use or assign a new appropriate code.



### 4.8 Estimation of Ba se Year Emissions This section describes the estimation of base year emissions for use in planning inventories for ozone, PM 2.5 and regional haze implementation

. S ubsections cover point, nonpoint, on

- road mobile, nonroad mobile, biogenic sources, and fires , respectively.

4.8.1 Stationary Point Stationary point sources can be estimated through continuous measurements and through more traditional methods

. EIIP Volume II, Chapter 1 , Sect ions 1 through 7 provide still

- relevant information on compilation and calculation of point source inventories

. Readers developing point source inventories should also use that report as a resource.

Sources estimated with CEMS
The best estimate of stationary point source emissions is obtained through the use of CEMS

. Several pollutants, including NO X , SO 2 , CO 2 , and mercury ( Hg ) can be measured with CEMS

. F uel heat input on an hourly basis is usually also be collected as part of the EPA’s CEMS programs, and heat content can be used to estimate emissions for other pollutants using emission factors (with specific test

- based factors preferred)

. More information and guidance on CEMS can be found at http://www.epa.gov/ttnemc01/cem.html and http://www.epa.gov/airmarkets/emissions/ continuous

- factsheet.html

. The vast majority of CEMS

- equipped sources use thes e measurements as part of reporting programs to the EPA

. In particular, the Acid Rain Program and NO X SIP call and other trading programs collect data as part of the EPA’s Clean Air Markets . Through that program, CEMS

- based emissions are available through the “Data and Maps” resource, including emissions summaries and files ready to be used in the Sparse Matrix Operator Kernel Emissions ( SMOKE ) system used for emissions modeling

.
For a few s ources, emissions must be report ed only for part of the year

. In these cases, users of the data should be careful not to override the annual emissions estimates for such units with the partial

- year data included in the CEMS databases

. This can be a particu lar challenge for modeling inventories, where the more temporal resolution is useful for the time periods covered, but the other time periods must use a different approach to apportion the remaining emissions to the rest of the year.
Other (non

- CEMS ) sourc es
EIIP Volume II, Chapter 1 , Section 4 provides general emission estimation procedure information

. It provides a table similar to Table 17 , but also focuses on the cost associated with the different

21 Some SCCs are set up for use in collecting source test data and developing emission factors. Sometime after that, the SCCs can be u sed for creating and submitting inventories, depending on the availability of emission factors and/or the interest for using those SCCs by industry and air agencies.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

61 approaches

. It acknowledges that the cost incurred with collecting the more specific source test data should be commensurate with the need for a higher data quality

. Like the EIIP figure, Table 17 also lists the more costly (and better) approaches higher on the list

. The EIIP volume provides guidance on each of the various methods of computing emissions.

The remainder of EIIP Volume II includes chapters that address various combustion, manufacturing, and production activities that are point sources

. Information in these chapters can be used to estimate
ozone, PM 2.5 , and regional haze precursor emissions where they address the source categories of interest

. In some cases, the EIIP chapters are somewhat dated and so may not cover newer emissions
processes

. In these cases, inventory developers should adapt the tec hniques or develop new techniques to ensure there estimates are relevant to t he sources

. The EIIP point source chapters within Volume II cover topics as follows (numbers correspond to chapter numbers) :

2. Boilers 3. Hot mix asphalt plants 4. Fugitive emissions from equipment leaks 5. Wastewater collection and treatment 6. Semiconductor manufacturing 7. Surface coating operations 8. Paint and ink manufacturing 9. Secondary metal production 10. Oil and gas production 11. Plastic products manufacturing 12. Effects of control device efficiencies and malfunctions 13. Stone mining and quarrying 14. Uncontrolled emission factors for criteria pollutants 15. Packaging and graphic arts 16. Chemical manufacturing
Each industry

- or source

- specific document contains a brief description; identification of emission points; an overview of methods available for estimating emissions; example calculations for each technique presented; a brief discussion on quality assuranc e ( QA ) and quality control ( QC ) ; and the SCCs needed for entry of the data into a database management system

. The SCCs included in each volume apply to the process emission points, in

- process fuel use, storage tank emissions, fugitive emissions, and
contro l device fuel (if applicable).

For NH 3 sources, a report is also available in the “nonpoint” section of EIIP entitled “ Estimating Ammonia Emissions From Anthropogenic Nonagricultural Sources

- Draft Final Report ” ( April 2004 ) and covers many point source p rocesses as well as nonpoint ones. Although a lot of research has been done on possible new approaches to agricultural NH 3 , these have not been completed yet

. At this time, the EPA augments agricultural NH 3 sources only as nonpoint sources, rather than as point sources.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

62 A final resource is to use the facility

- total NH 3 from the TRI

. For SIP planning inventory purposes, these emissions should be apportioned to individual processes, but at least can be a start ing point in the absence of other information.

Startup / s hutdown e missions
Since startup/shutdown emissions are planned and predictable, they should be included in SIP planning inventories. In instances when startup/shutdown emissions can be quantified i n both the base and future years, air agencies should include them in planning inventories because their reduction could help in achieving attainment . Since malfunctions are by nature unavoidable and unpredictable and given the myriad different types of ma lfunctions that can occur, malfunction emissions would be difficult to estimate and future

- year malfunction events cannot be readily predicted. Thus, states are not obligated to include malfunction emissions in the base inventory for the NAA, ROP/RFP plans , or attainment projected inventory for the NAA.
Startup/shutdown emissions can be quantified by assessing the emissions during startup or shutdown periods using traditional emissions estimation approaches of throughput and emission factors. However, the t hroughput and emission factors must be customized for the activity during these periods. Generally, emissions rates during these periods are higher and less well characterized than a typical operating emissions rate, and so some degree of expert judgement may be needed in assessing these emissions.
In addition to estimating the actual emissions during startup/shutdown periods, another approach to estimate startup/shutdown emissions is to adjust control parameters via the emissions calculation parameters of rule effectiveness or primary capture efficiency. Using these parameters for startup/shutdown adjustments is not their original purpose, but can be a simple way to increase the emissions and still have a record of the routine versus startup/shutdown portio ns of the emissions. For example, a lower capture efficiency or rule effectiveness can adjust actual emissions to be higher, accounting for extra emissions from startup/shutdown activities . In the absence of measurements of throughput and/or emissions rate s during startup/shutdown periods, expert judgment may need to be used to define the adjustment factors to use. This approach, however, can complicate the use of the control parameters during development and documentation of control strategies since the co ntrol parameters reflect things other than controls

– thus, care should be taken when using this approach.
Emissions associated with HEDD periods

As described in Section 4.5 , when air agencies have determined that emissions associated with HEDD periods are important for addressing their nonattainment problem , those air agencies should include HEDD

- related emissio ns in their planning inventories . This subsection first describes what information is available to help assess when HEDD periods occur and to help provide activity data that could be used as part of estimat ing the associated emissions. Second, this subsect ion describes how to consider HEDD

related emissions in planning inventories ( e.g., the base year inventory for the NAA) as compared to those in modeling inventories.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

63 Emissions from HEDD periods can include additional emission s from more typical EGU boiler s, turbines, and other units ( collectively called peaking units) and also from combustion

- based sources of distributed generation such as large back

- up generators and other engines. A key challenge in developing emissions estimates for HEDD

- periods is dete rmining when the peaking units and distributed generation units

were operating and consequently produced emissions. In the case of peaking units, many of these sources have CEMS that record activity and emissions levels , and these data are reported to EPA

. In the case of distributed generation units, little or no information may be readily available in part because the energy produced by the backup generators and other engines is not measured by the i ndependent

s ystem o perators (ISO s ) , but rather may be experienced by the ISOs as a n unmeasured demand reduction.
During HEDD periods, energy customers may use backup generators to participate in demand response
programs. Though some useful i nformation may be available from the ISOs running those programs, tha t is not always the case. The specific r ules, reporting, and frequency of use will vary by the utility or ISO that is offering the demand response program. Demand response p rogram requirements vary and can include (a) c ompletely excluding the use of backup generators, (b) allowing the use of backup generators and requiring some reporting, and (c) not requiring customers to report anything about action s taken to provide the demand response. The lack of data on demand response backup activity has been noted b y others based on past analyses 22 , 23

. Where emissions from demand response programs may be important, air agencies should first collaborate with their state energy and public utility commission counterparts, who may have established mechanisms for informatio n collection and sharing. Air agencies may also need to asses the demand response programs in their area by work ing directly with ISOs.

S tarting in 2015 , the National Emission Standard for Hazardous Air Pollutants (NESHAP) and New Source Performance Standa rds for Reciprocating Internal Combustion Engines (RICE) ( 40 CFR Part 60, Subparts IIII and JJJJ and 40 CFR Part 63, Subpart ZZZZ ), also called the RICE rules, will r equir e owners/operators of emergency engines participating in emergency demand response pr ograms to report the dates and times that the engines operate for emergency demand response as well as engine information such as horsepower and model year . While the RICE rules do not require the reporting of NO X emissions or information about non

- emergency programs, they will start to help provide information useful for understanding the activity of these back

- up generators and engines , which may also be helpful for ozone planning purposes

. While it may continue to be difficult to find data needed for assessing HEDD

- related emissions, air agencies may still include these emissions in both their modeling inventories and planning inventories. The HEDD

- related emissions included by air agencies in planning inventorie s should have some logical relationship with the emissions in modeling inventories

. The planning inventories will of course be limited spatially to the NAA, while the modeling inventories will cover a larger area. Air agencies should

22 White paper: “ Air Quality, Electricity, and Back

- up Stationary Diesel Engines in the Nor theast ,” Northeast States for Coordinated Air Use Management (NESCAUM), August 1, 2012.
23 See also the Mid

- Atlantic Distributed Resources Initiative (MADRI) working group meeting information available at http://sites.energetics.com/madri/meetings_2012.html

.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

64 extract the appropriat e NAAs to include in the planning inventories. Temporally, t he modeling inventories will include day

- and hour

- specific emissions for seasonal or episodic periods , which can include HEDD period s , while the planning inventories will be a summer day emission s value. As explained in Section 4.5 , the days used to calculate the summer day emissions are chosen for the particular SIP in consultation with the regional office . Some examples of possible relationships between the modeling inventories (episode

- specific) and the planning inventories (summer day) are as follows:

 Summer day emissions could be an average across all days of the episode

- specific emissions used in the m odeled attainment demonstration

.

 Summer day emissions could be an average of a longer episode or series of episodes that overlap with the episodic period used for the modeled attainment demonstration.

 Summer day emissions could be a representative selectio n of the episodic

- specific emissions, such as a median emissions value or using a single day emissions value that somehow is representative of other days.
These are not the only possible examples. A ny approach chosen to determine appropriate HED D

- related summer day emissions should be developed in consultation with the regional office and should seek to meet the overall goal for the base year inventory . Namely, the NAA inventory should be representative of the emissions conditions within the NAA that typically lead to nonattainment problems.

4.8.2 Stationary Nonpoint Nonpoint sources collectively represent individual sources that have not been inventoried as specific point or mobile sources

. These individual sources treated collectively as nonpoint sou rces are typically too small, numerous, or difficult to inventory using the methods for the other classes of sources

. Stationary nonpoint sources can be estimated through numerous different approaches

. Though some approaches are outdated, the EIIP Volume II I , Chapter 1 , Sections 1 through 6 provide relevant information on compilation and calculation of nonpoint source inventories

. Also , the Volume III webpage contain a re numerous supplemental reports for specific source categories

. For many categories, more updated approaches are included in the EPA tools developed for use by air agencies in developing inventories

. The latest tools are provided as part of the materials for the latest NEI

– either as developmental materials for an ongoing NEI effort, or as supporting materials to document a completed NEI effort.

Table 18 provides a list of emissions categories, pollutants, and available approaches documentation and/or tools.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

65 Table 18 : List of nonpoint categories, pollutants, and available approaches and tools

EPA

- estimated emissions source description Possible

Overlap with Point Available Nonpoint Resources (Posted year)

Agricultural Fertilizer Application ag_fertilizer_application_2011.zip (2013) Agricultural Fires 2011 NEI Technical Support Document , Section 5.2 Agricultural Tilling agricultural_tilling_2801000003_2011.zip (2012) Animal Husbandry animal_livestock_emissions_2011.zip (200 9) Architectural Coatings surface_coatings_arch_coatings_whaps_2011.zip (2012) EIIP, Volume III , Chapter 3 (1995)

Asphalt Paving asphalt_paving_cutback_2011.zip (200 9 ) asphalt_paving_emulsified_2011.zip (2009 ) EIIP, Volume III , Chapter 17 (2001) Asphalt Roofing Kettles Y See abstract available with the EIIP Volume III website (2000) Autobody Refinishing Y surface_coating_automobile_refinishing_2011whaps.zip (2012)

Aviation Gasoline av_gasoline_distribution_stage1.zip (2009) av_gasoline_distribution_s tage2.zip (2009) Commercial Cooking commercial_cooking_2302002nnn_2011.zip Consumer & Commercial

– All personal care products cons_comm_personal_care_products_whaps_2011.zip EIIP Volume III , Chapter 5 (1996)

Consumer & Commercial

– All household products cons_comm_misc_products_whaps_2011.zip cons_comm_cleaning_products_whaps_2011.zip cons_comm_auto_aftermarket_whaps_2011.zip EIIP Volume III , Chapter 5 (1996) Consumer & Commercial

– All coatings and related products cons_comm_coatings_and_related_products_whaps_2011.zip

Consumer & Commercial

– All adhesives and sealants cons_comm_adhesives_sealants_whaps_2011.zip EIIP Volume III , Chapter 5 (1996)

Consumer & Commercial

– All FIFRA related products cons_comm_fifra_whaps_2011.zip

Degreasing Y degreasing_whaps_2011_eisformat.zip Dental Preparation and Use Documentation for the 1999 Base Year Nonpoint area source National Emissions inventory for HAPs, page A

- 30 (2000) Dry Cleaning Y dry_cleaning_emissions_2011_rev. zip EIIP, Volume III , Chapter 4 (1996) Dust

– Paved Roads roads_paved_2011.zip Dust

– Unpaved Roads roads_unpaved_2011.zip

Dust

– Construction construction_residential_2011 .zip construction_nonresidential_2011.zip construction_road_2011.zip

Gasoline Distribution/Marketing Y gasoline_distribution_stage_1_bulk_plants_2011.zip (2009) gasoline_distribution_stage%201%20bulk_terminals_2011.zip (2009) gasoline_distribution_stage_1_pipelines_2011.zip (2012) gas_distribution_service_station_unloading_eis_format. zip (2012)Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

66 EPA

- estimated emissions source description Possible

Overlap with Point Available Nonpoint Resources (Posted year)

gasoline_distribution_stage1_ust_2011.zip (2012) gasoline_distribution_stage_1_tank_trucks_2011.zip (2012) gasoline_distribution_stage_2.zip (2012) EIIP, Volume III , Chapter 11 (2001) General Laboratory Activities Documentation for the Final 2002 Nonpoint Sector (Feb 2006 version) National Emissions inventory for Criteria and HAPs, page A

- 106 (2006) Graphic Arts Y graphic_arts_w_haps_2011.zip (2013) EIIP Volume III , Chapter 7 (1996) Human Cremation Y cremation_2011.zip (2000) Industrial, Commercial/Institu

tional Fuel Combustion Y ici_fuel_c ombustion_by_state/ (2013) Estimating Ammonia Emissions From Anthropogenic Nonagricultural Sources

- Draft Final Report (April 2004)

Industrial Surface Coating Y surface_coating_factory_finished_wood_2011whaps.zip (2012) surface_coating_wood_furniture_2011whaps_rev_4.zip (2012) surface_coating_metal_furn_2011whaps.zip (2012) surface_coating_paper_film_foil_2011_whaps.zip (2012 surface_coatings_metal_can_whaps_2011.zip (2012) surface_coating_machinery_and_equip_whaps2011.zip (2012) surface_coating_appliances_2011whaps.zip (2012) surface_coating_electr onic_and_other_electical_coatings_whaps_2011.zip (2012) surface_coating_motor%20vehicles_whaps_2011.zip (2012) surface_coating_aircraft_mfg__2011whaps.zip (2012) surface_coating_marine_mfgwhaps2011.zip (201 2) surface_coating_railroad_whaps_2011.zip (2012) surface_coa ting_misc_mfg_2011whaps.zip (2012) surface_coating_ind_maint_coating_2011whaps.zip (2012) EIIP, Volume III , Chapter 8 (1997) Lamp Breakage (Landfill emissions) Documentation for the Final 2002 Nonpoint Sector (Feb 2006 version) National Emissions inventory for Criteria and HAPs, page A

- 109 (2006) Lamp (Fluorescent) Recycling Documentation for the Final 2002 Nonpoint Sector (Feb 2006 version) National Emissions inventory for Criteria and HAPs, page A

- 107 (2006) Landfills Y EIIP, Volume III , Chapter 15 (2001) Mining and Quarrying mining_and_quarrying.zip (2012)

Oil and Gas Production Y EPA_Oil_and_Gas_Production_Emission_Estimation_Tool_2011_NEI_V1_4_ 20130919.zip (2013) Open Burning (Leaves, Brush, Resi dential Household Waste, Land Clearing) open_burning_yard_waste_2011.zip (2011) open_burning_yard_waste_2011.zip (2011) open_burning_msw_2011.zip (2011) open_burning_land_clearing_debris_2011.zip (2011) Other Special Purpose Coatings Y surface_coating_other_special_purpose_whaps_2011.zip

Pesticide Application cons_comm_fifra_whaps_2011.zip (2009 ) agricultural_pesticides_2011_eis_format.zip (2009 ) EIIP Volume III , Chapter 9 (2001) Portable Gas Cans (Residential and portable_fuel_containers_2011.zip (2012 )Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

67 EPA

- estimated emissions source description Possible

Overlap with Point Available Nonpoint Resources (Posted year)

Commercial) Publicly Owned Treatment Works Y potw_2011_rev.zip (2009 )

Residential Heating

- Fossil Fuels residential_consumption_ coal.zip (2012 ) residential_cons umption_oil_revised_06272012.zip (2012) residential_consumption_kerosene.zip (2012) residential_consumption_ng_revised_06222012.zip (2012) residential_consumption_lpg.zip (2012) Estimating Ammonia Emissions From Anthropogenic Nonagricultural Sources

- Draft Final Report (April 2004) See also abstracts available for coal, fuel oil & kerosene, gas & liquified petroleum gas (LPG) available with the EIIP Volume III website (1999). Residential Heating

– Wood rwc_estimation_tool_2011v1_120612.zip (2012) EIIP, Volume III, Chapter 2 (2001) Structure Fires EIIP, Volume III, Chapter 18 (2001) Traffic Markings traffic_marki ngs_whaps_2011.zip (2012) EIIP, Volume III , Chapter 14 (1997) Vehicle Fires See abstract available with the EIIP Volume III website (2000) Waste Disposal (Incineration) Estimating Ammonia Emissions From Anthropogenic Nonagricultural Sources

- Draft Final Report (April 2004)

As indicated in Table 18 by the column “Possible Overlap with Point
, ” some source types can have emissions in both the point source data category and the nonpoint one

. Some categories in the table that may have both types of sources are denoted, and this list is based on what has been seen in the NEI

. The list of categories in this situation depend on an individual state’s policies, such as what the emissions size threshold is for a point source and whether any catego ries are treated as point sources despite having low individual emissions.
To prevent overestimation of nonpoint emissions for sectors that also have point sources, it is important to perform point/nonpoint reconcil i ation

. This reconciliation starts by sub tracting the activity associated with the point sources from the total activity data ( prior to computing the nonpoint emissions )

. Since point sources often have emissions controls, it is usually not sufficient to just subtract point source emissions from t otal activity

- based emissions to prevent double counting. Subtracting controlled point source emissions from uncontrolled total activity

- based emissions would result in too much nonpoint emissions

. Rather, the point source activity must be determined and s ubtracted from total activity to get the nonpoint activity estimate

. Alternatively, uncontrolled point source emissions can be calculated and subtracted from the total activity

- based emissions estimates to derive a nonpoint emissions estimate

.
Part of developing refined nonpoint emissions estimates for a SIP could involve the use of surveys to collect data

. Inventory preparers often use survey questionnaires to gather point source emissions inventory data. The EIIP Volume III, Chapter 24 , written in 2000, provides guidance on developing and conducting surveys for area source inventories

. Since this document predates some of the newer online survey techniques, the sections des cribing the use of the internet are outdated

. As part of theEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

68 documentation for inventories, survey design and results should be kept and included in any documentation reports or appendices.

4.8.3 On

- road Mobile Emissions from on

- road vehicles are the result of several emission processes, including the combustion of fuel while vehicles are starting, idling, and moving, evaporation of fuel from the fuel system and during refueling, and from brake wear and tire wear.

For all states but California, on

- road mobile em issions should be estimated with the latest EPA on

- road mobile model, MOVES 24

, following the latest guidance available at http://www.epa.gov/otaq/models/moves/index.htm#sip

. For Californi a, the most re c ent EPA

- approved version of EMFAC should be used.
The available guidance covers using MOVES for inventory development in SIPs in states other than California

. The guidance focuses on determining what the appropriate inputs are and how MOVES should be run to develop emissions estimates for on

- road vehicles

. It describes when default MOVES inputs are appropriate for SIPs and regional conformity analysis and what factors to consider for providing locality

- specific MOVES inputs.

MOVES estimates e missions for mulitple source use types (the terminology that MOVES uses to describe vehicle type) and fuel types

. MOVES also estimates emissions for different road types that represent rural and urban unrestricted and restricted (accessed only by an on or off ramp) access roads, as well as off

- network emissions such as vehicle starts, evaporative emissions while parked, and hoteling emissions when long

- haul combination trucks are parked for long periods with the engine running under load.
One of the key ele ments for use of MOVES is creating a Run Specification (RunSpec) file, which defines the place and time period of the analysis as well as the vehicle types, road types, fuel types, and the emission

- producing processes and pollutants that will be included i n the MOVES run

. The MOVES Technical G uidance describes using the MOVES graphical user interface GUI to set up a MOVES run for a particular scale (e.g., county), time period, set of pollutants, and the vehicle types, road types, and fuel types applicable to a particular area and time.
Another key element for use of MOVES is entering local meteorology, fleet, activity, fuel, and control measure information using the County Data Manager. The MOVES Technical Guidance discusses when local data should be used in place of model default data, as well as potential sources of local data.
For some input parameters, there is overlap with the inputs needed for other models, such as the nonroad mobile models, for example, meteorology and fuels

. Efforts should be made to use the same source of data across multiple categories when the inputs are shared

. Not doing so calls into question

24 The EPA expects that MOVES 2014 will be released after this draft guidance is released and before this guidance is finalized. EPA intends to modify this section as relevant for use of MOVES 2014, including expected changes to SCCs. EPA will also modif y the MOVES guidance accordingly.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

69 the validity of one or both approaches

. Air agencies should explain the use of shared inputs, or reasons for not using them, as part of t he documentation provided with their inventories.

4.8.4 Nonroad Mobile Equipment Nonroad mobile equipment emissions result from the use of fuel in a diverse collection of vehicles and equipment, including:

 recreational vehicles, such as all

- terrain vehicles and off

- road motorcycles;

 logging equipment, such as chain saws;

 agricultural equipment, such as tractors;

 construction equipment, such as graders and back hoes;

 industrial equipment, such as forklifts and sweepers;

 residential and commercial lawn and garden e quipment, such as leaf and snow blowers;

 recreational marine vessels, such as power boats.

The EPA’s NONROAD emissions model predicts emissions for all of these nonroad equipment categories

. Emissions from CMVs , locomotives, and aircraft are estimated in o ther ways and described in Section 4.8.5

. The NONROAD model includes more than 80 basic and 260 specific types of nonroad equipment and further stratifies equipment types by horsepower rating

. Fuel types include gasoline, diesel, compressed natural gas ( C NG ) , and Liquified Petroleum Gas ( LPG )

. The NONROAD model estimates emissions for all criteria pollutant and precursors from both exhaust and non

- exhaust processes ( diurnal, refueling spillage, vapor displacement, hot soak, running loss, take permeation, hose permeation, and crankcase emissions)

. NONROAD supports many SIP

- related inventor y development needs , including support for partial counties and seasonal emission s

. The EPA provides the latest version of the NONROAD model and all information related to its use for inventories
at http://www.epa.gov/otaq/nonrdmdl.htm

. Air agencies should use NONROAD as a resource for estimating nonroad mobile emissions and refer to the documentation on the NONROAD website for more information

. The EPA is currently in the process of incorporating NONROAD model capabilities into MOVES. When this update is available, guidance on the transition to using MOVES for estimating nonroad emissions will be included on the EPA’s MOVES and NONROAD web pages.

The NONROAD model can be run by itself or using the NMIM interface ( http://www.epa.gov/otaq/nmim.htm )

. NMIM adds several features to enhance nonroad emissions modeling , including:

 The inclusion of all the required county data for the nation in a single database

 A graphical user interface

 Shortcuts for ge nerating national (or multi

- region) inventories

 Estimation of 33 HAPs, and 17 dioxin/furan congeners by ratio to various NONROAD output parameters

 Distributed processing capability to enhance model performanceEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

70 NMIM also includes the now no longer used MOBI LE6.2 model for on

- road emissions. MOVES has replaced NMIM for on

- road emissions estimation and, as a result, the use of on

- road emissions estimates from NMIM is not currently acceptable for any regulatory purpose.

Based on a user

- provided run specificati on (RunSpec) file and informati on in the NMIM county d atabase , NMIM creates input files for NONROAD for every county and month selected

. NMIM then runs NONROAD, reads its output files, performs additional processing if necessary, and puts the resulting inv entory into an output database

. Additional processing includes creating HAP emission estimates from the CAP estimates

. NMIM has post

- processing capability that can be applied after the inventory is generated

. This includes aggregation over months and equip ment types

. Output can go into a database table or into a tab

- delimited text file

. The format can be normalized (a pollutant on each line) or wide (a pollutant in each column).

Air agencies have the option of replacing default model inputs with more repres entative data

. Common input adjustments include equipment population, geographic allocations, and local growth rates

. If agencies make changes to default model values, the agency should submit the input files to the EPA as well as a description of why the defaults were changed

. Additional guidance on improving n onroad estimates for lawn and garden equipment can be found in EIIP, Volume IV , Chapter 3.
For some input parameters, there is overlap with the inputs needed for other models, such as the on

road mobile models, for example, meteorology and fuels

. Efforts should be made to use the same source of data across multi ple categories when the inputs are shared

. Not doing so calls into question the validity of one or both approaches

. Air agencies should explain the use of shared inputs, or reasons for not using them, as part of the documentation provided with their inventories.

4.8.5 Other Nonroad Mobile The NONROAD model does not provide air agencies with a tool for estimating emissions for C MVs , aircraft, and locomotives

. Thus, separate methods are used for each of these emissions sectors.
For purposes of reporting data to the EPA , the aircraft emissions are often reported as point sources, with this being a requirement for reporting data to the EIS for use in the NEI

. Likewise, the CMV and locomotive data are included in the nonpoint data category in the EIS

. While these sources are still mobile sources from the traditional standpoint of common

- sense categories, for data formatting and report ing purposes in the EIS , they are treated along with these non

- mobile data categories.

4.8.5.1 Aircraft The aircraft sector includes all aircraft types used for public, private, and military purposes. This includes four types of aircraft: (1) Commercial, (2) Air Taxis (AT), (3) General Aviation (GA), and (4) Military

. A critical detail about the aircraft is whether each aircraft is turbine

- or piston

- driven, which allows the emissions estimation model to assign the fuel used, jet fuel or aviation gas, respectively

. The fraction of turbine

- and piston

- driven aircraft is either collected or assumed for all aircraft types. NEI data are available for this sector for use as a starting point in SIPs, though the NEI includes military aircraft only where state or local air agencies have submitted military aircraft emissions data.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

71 Commercial aircraft include those used for transporting passengers, freight, or both

. Commercial aircraft tend to be larger aircraft powered with jet engines

. ATs carry passengers, freight, or both , but usually are smaller aircraft and operate on a more limited basis than the commercial aircraft

. GA includes most other aircraft used for recreational flying and personal transportation

. Finally, military aircraft are associated with military purposes, and they sometimes have activity at non

- military airports.
The national AT and GA fleet includes both jet

- and piston

- powered aircraft

. Most of the AT and GA fleet are made up of larger piston

- powered aircraft, though smaller business jets can also be fou nd in these categories

. Military aircraft cover a wide range of aircraft types such as training aircraft, fighter jets, helicopters, and jet

- powered and piston

- powered planes of varying sizes.
Emissions at airports also include other sources that are a part of the nonroad equipment emissions described in Section 4.8.4

. These emissions come from aircraft auxiliary power units (APUs) and aircraft ground support equipment (GSE) typically found at airports, such as aircraft refueling vehicles, baggage handling vehicles, and equipment, aircraft towing vehicles, and passenger buses

. In the NEI point source inventory, these APUs and GSE are located at the airport faci lities as point sources along with the aircraft exhaust emissions (though not as part of the aircraft sector). Emissions from APUs and from GSE are calculated using the EPA ’s NONROAD model.

The EPA collaborates with the Federal Aviation Administration (FAA ) to develop and maintain methods for estimating aircraft emissions using the Emissions and Dispersion Modeling System (EDMS), which estimates emissions from aircraft

. The EPA

- developed emissions are associated with aircrafts’ landing and takeoff (LTO) cycle

. The EPA encourages state and local air agencies to collect aircraft activity data that can be used in improving estimates using the EPA EDMS

- based me thods

. More details on the EPA methods are available in the latest NEI documentation found at http://www.epa.gov/ttn/chief/eiinformation.html

.
The aircraft sector includes numerous SCCs as show n in Table 19 , and all but two of these are associated with the NEI point source inventory

. Historically, airport emissions have been calculated as a nonpoint
source, but with the latest approaches having all airport locations readily available, such a simplification is no longer needed

. The result of this change from nonpoint to point sources is that most of the SCCs are shown as 10

- digit SCCs (usually used just for no npoint sources) but are now used as point SCCs

.

Table 19 : Aircraft SCCs and Data Categories in EPA Estimates

SCC Data Category SCC Description EPA estimates 2275001000 Point Mobile Sources; Aircraft; Military Aircraft; Total X

2275020000 Point Mobile Sources; Aircraft; Commercial Aircraft; Total: All Types X

2275050011 Point Mobile Sources; Aircraft; General Aviation; Piston X 2275050012 Point Mobile Sources; Aircraft; General Aviation; Turbine X 2275060011 Point Mobile Sources; Aircraft; Air Taxi; Piston X 2275060012 Point Mobile Sources; Aircraft; Air Taxi; Turbine X

2260008005 Point Mobile Sources; Off

- highway Vehicle Gasoline 2

- Stroke; Aircraft Ground Support Equipment XEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

72 SCC Data Category SCC Description EPA estimates

2265008005 Point Mobile Sources; Off

- highway Vehicle Gasoline 4

- Stroke; Aircraft Ground Support Equipment X

2267008005 Point Mobile Sources; LPG; Aircraft Ground Support Equipment X

2268008005 Point Mobile Sources; CNG; Aircraft Ground Support Equipment X

2270008005 Point Mobile Sources; Off

- highway Vehicle Diesel; Aircraft Ground Support Equipment X

2275070000 Point Mobile Sources; Aircraft; Aircraft Auxiliary Power Total X

2275085000 Nonpoint Mobile Sources; Aircraft; Unpaved Airstrips; Total

2275087000 Nonpoint Mobile Sources; Aircraft; In

- flight (non

- Landing

Takeoff cycle) X

In June 2012, the EPA published standards for NO X emissions from commercial aircraft engines

. Information about this rule including fact sheets, test procedures, and emissions documentation is available on the EPA website for this purpose ( http://www.epa.gov/otaq/aviation.htm ). In this rule, the EPA adopted Tier 6 and Tier 8 standards for NO X on new aircraft engines, with compliance dates in 2013 and 2014

. Prior rules published in 2005 and 1997 also reduce aircraft NO X emissions with engine standards; these rules are also documented on the same website

. When estimating emissions from aircraft, it is best practice to consider the impacts of these rules for improving the accuracy of emissions inventories

. This is why the EPA recommends using the EPA EDMS

- based approach with locality

- specific data.
State or local air agencies may determine that the EPA default method is not appropriate for SIP purposes, though the EPA recommends considering the approach but using more locality

- specific activity information

. For areas that have provided the EPA locality

- specific airport activity data, the NEI estimates may very well provide emissions needed to meet SIP requireme nts

. The EPA method is more robust than older methods and includes national control programs as noted below

. As shown in the table above, the EPA ’s methods do not estimate emissions from unpaved airstrips (SCC 2275085000)

. Furthermore, the “in

- flight” SCC (2275087000) is covered by the EPA ’s method for only lead (Pb) emissions and is related to general aviation aircraft that still use leaded fuel

. A ir agencies may want to consider unpaved airstrips and/or in

- flight emissions for other pollutants as part of their inventories for improved model performance or other reasons, though doing so may not be necessary depending on the significance of those emissions in a particular area

. Any locality

- specific data or custom emissions associated with aircraft sources a re expected to be included with supporting documentation for the emissions inventory used for a SIP.

4.8.5.2 Commercial Marine The CMV emissions category includes boats and ships used either directly or indirectly in the conduct of commerce or military activity

. The majority of vessels in this category are powered by diesel engines that are either fueled with distillate or residual fuel oil blends

. For the purpose of this inventory , we assume that Category 3 (C3) vessels primarily use residual blends while Categor y 1 and 2 (C1 and C2)Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

73 vessels typically use distillate fuels. Another consideration for emissions estimation of CMV sources is auxiliary engines

. All three types of vessels may have auxiliary engines that are used for onboard power generation or other need s.
The C3 inventory includes vessels which use C3 engines for propulsion

. C3 engines are defined as having displacement above 30 liters per cylinder

. C3 inventories typically include emissions from both propulsion and auxiliary engines used on these vessel s, as well as those on gas and steam turbine vessels

. Geographically, the inventories include port and interport emissions that occur within the area that ex tends 200 nautical miles from the official U.S. shoreline, which is roughly equivalent to the borde r of the U.S. Exclusive Economic Zone

. For national inventories created by the EPA , only some of these emissions are allocated to states based on official state boundaries that typically extend 3 nautical miles offshore

. The EPA recommends that state water boundaries also be used when determining which emissions should be included with a particular state or county.
The C1 and C2 vessels tend to be smaller ships that operate closer to shore, and along inland and intercoastal waterways , with engines greater t han or equal to 37kW

. Naval vessels are not included in C1 and C2 vessel inventories, though Coast Guard vessels are included

. While these C1/C2 vessels are most often associated with near

- land applications and thus included as within state waters, sometim es these vessels are used outside of state waters, particularly in the Gulf of Mexico

. In these cases, as with C3 vessels the EPA recommends that state water boundaries be used when calculating emissions associated with a particular state or county.

The CM V source category does not include recreational marine vessels, which are generally less than 100 feet in length, most being less than 30 feet and powered by either inboard or outboard engines

. The calculation of these emissions is included in the NONROAD model , and these emissions are therefore considered “nonroad equipment”.

The EPA develops and maintains methods for estimating CMVs , and these methods are used as “fallback” methods for use in the NEI

. They are also available as a fallback for states witho ut other data for this sector

. At this time, the EPA ’s methods are top

- down national methods, which apportion nationally estimated emissions values to the states and counties

. In the latest such approaches (used for the 2008 and 2011 NEI), this apportionment includes allocation to GIS shapefiles for ports and underway emissions

. These shapefiles are available with the latest NEI documentation and include separate files for ports and underway

. Key differences associated with various EPA methods fr om the 2002 NEI through the 2011 NEI have focused on allocation of emissions to the shapefiles, which has been done in collaboration with state and local air agencies.

The current EPA methods also use emissions types

. Each of the CMV SCCs requires an appro priate emissions type (M=maneuvering, H= hotelling , C=cruise, Z=reduced speed zone)
, because emission factors vary by emission type

. For the NEI, e ach SCC and emissions type combination was allocated to a shapefile identifier in the nonpoint inventory

. The allowed combinations of SCCs and emission types are shown in Table 20

. The default values are those assumed when the actual emission type may beEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

74 unknown; for example, emissions that occur in shipping lanes are assumed to be ‘cruising’ and cannot be ‘hotelling
, ’ which only occurs at ports.

Table 20 : Commercial marine SCCs and emission types in EPA emissions

SCC SCC Description Allowed Default 2280002100 Marine Vessels, Commercial Diesel Port M M 2280002200 Marine Vessels, Commercial Diesel Underway C C 2280003100 Marine Vessels, Commercial Residual Port H H 2280003100 Marine Vessels, Commercial Residual Port M H 2280003200 Marine Vessels, Commercial Residual Underway C C 2280003200 Marine Vessels, Commercial Residual Underway Z C

State or local agencies may determine that the EPA default method is not appropriate for SIP purposes
or may need further refinement by air agencies in developing SIPs

. For example, the general calculation method may be a reasonable approach, but the activity and spatial allocation achieved from a top

- down approach could be improved by using the same methods with locally resolved input data t o calculate emissions for specific areas.
When estimating CMV emissions, reporting agencies should consider national regulations that decrease emissions from this sector , such as increasingly stringent emissions requirements for n ew marine diesel engines and sulfur requirements for marine diesel fuel and adjust their estimates accordingly

. Emissions reductions resulting from requirements for new marine engines are generally not immediately reflected in inventories as newer engines are gradually incorporate d into the vessel fleet and as older engines/vessels are retired

. Emissions reductions resulting from the use of lower sulfur fuels are generally seen more quickly, though estimating impacts can be complicated by vessels coming from other parts of the worl d with different fuel standards. Table 21 provides a list of more recent relevant regulations and associated references for the CMV category

. Older Tier 1 and 2 regula tions on marine diesel engines , dating back to 1999, are also listed on the websites shown in the table

.

Table 21 : Commercial m arine v essel recent regulations and impacted pollutants

Regulation Pollutants impacted Reference Great Lakes Steamship Repower Incentive Program (January, 2012) SO 2 , PM 2.5 www.epa.gov/otaq/ oceanvessels.htm Tier 2 and Tier 3 Emissions Standards for Category 3 Marine Diesel (April

, 2010). Includes both engine standards and fuel sulfur limits. SO 2 , NO X , PM 2.5
Tier 3 and Tier 4 Emission Standards for Category 1 and 2 Marine Diesel Engines (June, 2008)

. PM 2.5 , NO X www.epa.gov/otaq/ marine.htm#regs Nonroad Diesel Tier 4 Rule (May 2004) . Decreased allowable levels of sulfur in marine diesel fuel by 99%, taking affect in 2007. SO 2

For states needing to refine their emissions estimates beyond the values produced by the EPA ’s default methods, Tabl e 22 provides a list of the latest resources for states in better understanding how toEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

75 calculate emissions for the CMV sources

. The newer references are included higher in the table

. The EPA’s recent method updates have occurred in conjunction with rule development efforts, and so some of these documents are associated with inventories developed for the rules listed above

. Even newer methods may become available over time and can be considered for use in SIP planning inventory development

. Much of this information is also available on the EPA nonroad mobile website under “other references”, available at http://www.epa.gov/otaq/nonrdmdl.htm#otherref

. Any locality

- specific data or custom emissions associated with CMV emissions are expected to be included with supporting documentation for the emissions inventory used for a SIP.

Tabl e 22 : : Current EPA methods for commercial marine vessel emissions. Inventory approach resource CMV Approaches For... Reference Current Methodologies in Preparing Mobile Source Port

- Related Emissions inventories (April, 2009) Ocean going (generally C3) vessels, harbor craft, cargo handling, http://www.epa.gov/sectors/ sectorinfo/sectorprofiles/ports/ ports

- emission

- inv

- april0 9.pdf

Draft Regulatory Impact Analysis: Control of Emissions of Air Pollution from Category 3 Marine Diesel Engines (June, 2009) Bottom

- up port C3 emissions for 89 deep water and 28 Great Lake ports in the U.S. and interport emissions from the Waterway Ne twork Ship Traffic, Energy and Environmental Model (STEEM). http://www.epa.gov/otaq/regs/ nonroad/marine/ci/420d09002.pdf

. See Chapter 3.

Final Regulatory Impact Analysis: Control of Emissions of Air Pollution from Locomotive Engines and Marine Compression Ignition Engines Less than 30 Liters per Cylinder (May 2008) C1 and C2 propulsion, C1 marine auxiliary, <37kW commercial propulsion, and <37kW marine auxiliary. http://nepis.epa.gov/Exe/ZyPURL.cgi ?Dockey=P10024CN.txt

. Chapter 1 provides more in

- depth description of engine types, while Chapter 3 provides emissions calculation approach.

Emissions i nventory improvement program Evaporative VOC emissions from marine transport of petroleum liquids, including the loading and unloading of the petroleum liquids

. ‡ EIIP, Volume III , Chapter 12 “ Marine Vessel Loading, Ballasting, and Transit ”.

‡ These emissions are often included in as part of the nonpoint inventory rather than associated with the CMV
sector.
Older approaches are also available

. In 1999, the EPA sponsored two studies entitled “Commercial Marine Activity for Great Lake and Inland River Ports in the United States” and “Commercial Marine Activity for Deep Sea Ports in the United States.” Both of these reports are available at http://www.epa.gov/otaq/nonrdmdl.htm#otherref

. These studies provide d activity profiles for approximately 150 ocean, lake, and river ports, and present a method for an inventory preparer to allocate time

- in

- mode a ctivity data from one of four typical ports to another port that has similar characteristics

. Activity profiles for a typical port include: 1) number of vessels in each category; 2) vessel characterization, including propulsion size (horsepower), capacity tonnage, and engine age; 3)Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

76 number of hours at each time

- in

- mode associated with cruising, reduced spee d, maneuvering, and hotelling

. These methods provide alternative approaches for state and local air agencies in preparing SIP inventories, but care shou ld be taken to incorporate the impact of national rules incorporated into the newer approaches as documented in Tabl e 22

.
4.8.5.3 Locomotives The locomotive emissions catego ry includes diesel

- electric engines, which use 2

- stroke or 4

- stroke diesel engines and an alternator or a generator to produce the electricity required to power its traction
motors

. The EPA default approach does not include locomotives powered by electrici ty or steam

. It is believed that the number of wood or coal driven steam locomotives in the U.S. is currently very small; therefore, these types of locomotives are not generally included

. In specific instances, if such sources are relevant to a NAA , then they may need to be included

. The locomotive sources are further divided into categories: Class I line haul, Class II/III line haul, Passenger, Commuter, and Yard.
Several definitions come into play in determining the locomotive category, which impacts the SCC that should be used.

 Class I railroads are those that operate in many different states over thousands of miles of track

. They are defined by the U.S. Surface Transportation Board as having annual carrier operating revenues of $250 million or more. As of 2014, there were 8 such railroads in the U.S

. : Amtrak and seven freight railroads, which were designated Class I based on 2011 measurements released in 2013 ( "Class I Railroad Statistics" . Association of American Railroads. April 17, 2013 .)

 Class II/III railroads are also known as short line and regional railroads, and they range in size from very small (a few carloads of freight per month) to multi

- state railr oads just under Class I size

. Class II railroads are defined as hav ing revenues greater than $20.5 million but less than $277.7 million for a least three consecutive years

. Switching and terminal railroads are excluded from Class II status

. A Class III rai lroad is defined as a rail company with annual operating revenue of less than $20 million.

 Line haul refers to higher power usage of locomotive engines during extended mileage. It is also associated with a test cycle used for estimating emission factors in tended to represent emissions during line

- haul activity.

The EPA develops and maintains methods for estimating locomotive emissions, and these methods are used in the NEI in the absence of more updated data from air agencies

. They are also available as a fallback for states without other data for this sector

. The EPA’s 2011 national rail estimates were developed by applying growth factors to the 2008 NEI values based on railroad freight traffic data from the 2008 and 2011 “R

- 1” reports submitted by all Cla ss I rail lines to the Surface Transportation Board and employment statistics from the American Short Lines and Regional Railroad Association for C lass II and III. In the latest such approaches (used for the 2008 and 2011 NEI), this apportionment includes allocation to GIS shapefiles for line

- haul and rail yard emissions

. The EPA project report Development of 2011 Railroad Component for National Emissions Inventory ( September 2012 ) provides the EPA ’s latest estimation approach and references the 2008 approach as well

. The report for the 2008 NEI was anotherEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

77 project report, called Documentation for Locomotive C omponent of the National Emissions Inventory methodology (May 2011).
The EPA default method was developed with a consortium of the EPA, state, and industry, led by the Eastern Regional Technical Advisory Committee (ERTAC)

. The ERTAC group provided data and reviewed methods as is described in the 2008 NEI Technical Support Document and associated documentation

. Table 23 lists the locomotive SCCs used in the EPA default m ethodology

. Other SCCs exist as valid SCCs, but are not used in the EPA method, so states should consider this when comparing the EPA estimates
to locality

- specific estimates and when merging emissions inventories that include both state/local components and the EPA estimates.

Table 23 : Locomotive SCCs

SCC Description EPA Estimated? Data Category

2285002006 Mobile Sources Railroad Equipment Diesel Line Haul

Locomotives: Class I Operations Yes

– in shape files Nonpoint

2285002007 Mobile Sources Railroad Equipment Diesel Line Haul

Locomotives: Class II / III Operations Yes

- in shape files Nonpoint

2285002008 Mobile Sources Railroad Equipment Diesel Line Haul

Locomotives: Passenger Trains (Amtrak) no Nonpoint

2285002009 Mobile Sources Railroad Equipment Diesel Line Haul

Locomotives: Commuter Lines no Nonpoint

2285002010 Railroad Equipment Diesel Yard Locomotives no Nonpoint

28500201 Internal Combustion Engines Railroad Equipment

Diesel Yard Yes

– as point

sources Point

State or local agencies may determine that the EPA default method is not appropriate for SIP purposes or may need further refinement by air agencies in developing SIPs

. A number of ways to improve the EPA estimates were noted in the original 20 11 report (see ftp://ftp.epa.gov/EmisInventory/2011/doc/2008nei_locomotive_report.pdf ) that documented the approach used for the 2008 NEI

. For the Class I line

- haul emissions, t he report identifies the most important consideration s such as the rail link

- level freight tonnage

. Other variables were not addressed in the methodology, including track grade and track speed

. While the method calculated railroad

specific fleet

- averaged emission factors from industry fleet data, it is note d that emissions from individual engines are highly variable even for the regulated engine categories depending on variables such as the specific locomotive model, operation cycle, and conditions of operation

. Furthermore, the EPA approach does not address the seasonality of the emissions, while activity levels of different engines do vary seasonally and could impact emissions for seasonal inventories

. Any locality

- specific data or custom emissions associated with locomotive sources are expected to be included with supporting documentation for the emissions inventory used for a SIP.
For the rail yard emissions, the same 2011 report notes additional considerations for improve ments. It notes that the use of tonnage hauled as an indicator of the amount of switching activity is an assumption that could reduce uncertainty. The variability associated with actual switching duty

- cyclesEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

78 and in the number of switchers operating at some rail yards seasonally was not considered in the method.
Locomotive idling emissions is another issue that is not clearly considered in the default EPA methodology and could have an impact on emissions estimates

. During normal operations, locomotives have numerous reasons why they may remain idling including the switching operations noted above

. The EPA has included regulations on idle emissions to help address this source

. More details on idling emissions from loc omotives is available in “ Control of Emissions from Idling Locomotives ” (EPA, March 2008).
The EPA website on locomotive regulations and locomotive emissions ( http://www.epa.gov/otaq/locomotives.htm ) provides a resource for understanding the regulations that apply to locomotives and how those may impact emissions

. Only one recent regulation impacts emissions from locomotives, while several older regulations also apply

. In June 2008, the EPA published the Control of Emissions of Air Pollution for Locomotive Engines and Marine Compression Ignition Engines Less than 30 Liters Per Cylinder. This rule includes standards for existing and remanufactured locomotives, Tier 3 and Tier 4 standards for newly built locomotives, and idle reduction requirements for new and remanufactured locomotives

. The rule reduces emissions of PM 2.5 and NO X . The emissions estimation approach used for this rule i s available in Chapter 3 of the Regulatory Impact Assessment for the rule , and this approach differs from the EPA method used for the NEI

. Associated with the rule, the EPA developed a fact sheet on locomotive emission factors (April, 2009) that can be used in estimating emissions from locomotives.

4.8.6 Biogenic and Geogenic Sources Biogenic sources are a subset of natural emissions sources that may contribute significantly to an emissions inventory

. Vegetation (i.e., forests and agriculture) is the predominant biogenic source of VOC and is typically the only source that is included in a biogenic VOC emissions inventory

. Microbial activity in the soil contributes to natural biogenic NO X and CO emissions

.
The EPA makes available biogenic emissions estimates as part of the NEI. Starting in 2008 NEI, the biogenic vegetation and soil emissions have been included in the official NEI releases. In some cases, these EPA

- generated emissions may be sufficient for use in SIP inventories other than modeling inventories.

Biogenic emissions from vegetation and soils are computed using a model which utilizes spatial information on vegetation and land use and environmental conditions of temperature and solar radiation 25

. The model inputs are typically horizontally allocated (gridded) data, and the outputs are gridded biogenic emissions which can then be speciated and utilized as input to photochemical grid models

. Several models exist, as described in the following subsections.

25 In most cases, ozone, PM, and regional haze modeling includes the emissions from vegetation and soils , but not other relevant sources such as volcanic emissions, lightning, and sea salt.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

79 Modeled b iogenic vegetation emissions are significant for understanding ozone formation, particularly in the Eastern U.S. , and the dependence o n meteorology makes using case

- specific meteorology very important

. In addition, t he impact and model characterization of biogenic terpene and sequiterpene on secondary aerosol format ion for PM modeling is thought to be important

. Emissions data developers should consider the latest available information on this issue where biogenic sources are key sources in their modeling region.

Biogenic Emission s Inventory System (BEIS)

The EPA has developed the Biogenic Emission s Inventory System, version 3.14 (BEIS3.14) for use in estimating biogenic emissions

. This model runs as a module of the SMOKE system, with the latest documentation available at http://cmascenter.org/smoke/

.

The key inputs to BEIS include:

 Temp erature data at 2 meters , which can be obtained from modeled meteorological data, such as data from the Weather Research and Forecasting (WRF) Model

. Such data are also needed for input to air quality models used for modeled attainment demonstrations sometimes needed as part of SIPs. The BEIS3.14 documentation has more information on the meteorological inputs.

 Land

- use data from the Biogenic Emissions Land U se Database, version 3 (BELD3)

. BELD3 data provides data on the 230 vegetation classes at 1

- km r esolution over most of North America

. These data are available at http://www.epa.gov/ttnchie1/emch/biogenic/

. These land use data can be created with the Multimedia Integrated Modeling System ( MIMS ) Spatial Allocator ( http://www.ie.unc.edu/cempd/projects/mims/spatial/ )

. Air agencies can alternatively rely on the EPA ’s 12

- km gridded data for modeling domains that overlap with the EPA national domain, provided with the EPA ’s latest modeling platform on the Emissions Modeling Clearinghouse

. Other Biogenic Models

Other bio ge nic models such as Model of Emissions of Gases and Aer o sols from Nature (MEGAN) ( http://acd.ucar.edu/~guenther/MEGAN/MEGAN.htm ) are acceptable as well, provided that the users have demonstrated th eir suitability for the modeling application (see Modeling Guidance for more information)

. A version of MEGAN has also be en incorporated into an air quality model called the WRF model coupled with Chemistry (WRF

- CHEM) ( http://www.acd.ucar.edu/wrf

- chem/ ). California has developed a GIS

- based biogenic model called BEIGIS ( http://www.arb.ca.gov/ei/biogenicei.htm )

. Another mod el is available called the Global Biosphere Emissions and Interactions System (GloBEIS ) ( http://www.globeis.com/ )

. The EPA previously made a comparison between BEIS and MEGAN ( available at http://www.cmascenter.org/conference/2008/slides/pouliot_tale_two_cmas08.ppt )

. BEIS, MEGAN, and other models continue to evolve and so agencies using these models should evaluable the suitability of one model over the other as part of a modeled attainment demonstration

. Once a choice has been made for modeling purposes, emissions should also be summed across the NAA for inclusion in the base year inventory for the NAA and/or the attainm ent projected inventory for the NAA

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80 Geogenic and Other Natural Sources
Geogenic emissions are primarily the result of oil or natural gas seeps and soil wind erosion

. In addition, lightning may also be a significant contributor to natural NO X emissions in an inventory area

. Volcanoes and fumaroles (i.e., vapor or gas vents in a volcanic region) can be additional sources of geogenic emissions.
As a source of ozone precursor emissions, geogenic sources are usually less significant than biogenic

sources

. Howe ver, geogenic wind erosion may contribute substantially to PM emissions in an area

. In 2012, the EPA released CMAQ v5.0 that includes a module that dynamically estimates hourly natural emissions of fine and coarse dust particles due to wind action over ari d and agricultural land

. This allows the contribution of this source to be included in a modeled attainment demonstration without the need to prepare an emissions inventory first

. The windblown dust approach is based on the work of Tong et al. (2011) (see also the CMAQ wiki at http://www.airqualitymodeling.org/cmaqwiki/ index.php?title=CMAQv5.0_Windblown_Dust )

. For the emissions inventory SIP, air agencies using this feature should evaluate the results of the CMAQ

- based approach to determine if it provides a reasonable representation of dust emissions in their modeling domain

. Often times, CMAQ overestimates ambient crustal matter concentr ations without the addition of windblown dust and so adding emissions may not be advisable

. If windblown dust emissions are included in SIP planning , such emissions should be included in the base year and attainment projected inventories to meet the requirements for a complete emissions inventory

. In the case of using CMAQ, t his would require that t he CMAQ

- based emissions be summed for the NAA

. Since CMAQ produces gridded emissions estimates , air agencies would need to sum emissions from t he relevant grid cells or portions of cells associated with the NAA and/or other geopolitical regio ns as appropriate

. One relevant detail about the AERR regarding windblown dust is that they are specifically exempted from the reporting requirements in 40 C FR 51.20(d)

State, local and tribal agencies should also prepare an inventory of all other significant geogenic sources in the inventory area

. Methods for estimating VOC emissions from oil and gas seeps, as well as NO X emissions from lightning, are describ ed in the EIIP document, Volume V, Biogenic Sources Preferred Methods available at http://www.epa.gov/ttn/chief/eiip/techreport/volume05/index.html

. For oil and gas seeps, the preferred method is to develop a local emission factor based on the study of oil or gas seeps in the inventory area.
Lightning produces NO, which is oxidized to NO 2 in the presence of ozone or in a photochemically reactive atmosphere

. This NO X is formed in the mid

- upper troposphere and can impact the distribution of reactive nitrogen as well as ozone. NO emissions from lightning can be estimated by collecting activity data on the cloud

- to

- ground lightning flashes, assuming a frequency of intra

- cloud flashes based on the value for cloud

- to

- ground lightning flashes, and applying appropri ate emission factors (in molecules NO per flash) to these activity levels

. Because lightning is not a direct source of NO 2 , accounting for this source category is more important for air quality modeling purposes than for SIP planning inventoryEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

81 purposes

. Gi ven the altitude of these emissions, it is not usually important to include these emissions in the base year inventory for the NAA or in the attainment projected inventory for the NAA

. CMAQ v5.0 includes a parameteriz ed approach to estimate NO X emissions and its vertical distribution that is generated from lightning. Over the Continental U.S., the a pproach can use lightning flash totals from the National Lightning Dete ction Network (NLDN). For cases where such data are not available, an alternate algorithm can be used that estimates the number of lightning flashes based on the modeled convective precipitation

. The peer reviewed literature contains both a description of the approach (Allen et al., 2011) and a model evaluation (Appel et al., 2010)

. More information is available from the CMAQ v5.0 wiki (see http://www.airqualitymodeling.org/cmaqwiki/ index.php?title=CMAQv5.0_Lightning_NO )

.
4.8.7 Wildland Fires Because the CAA specifies that planning inventories (e.g., the base year inventory for the NAA) must include all sources of emissions, the inventories therefore should include fires. Thus, wildfires and prescribed fires, including wildland fire use, should be included in the NAA inventories when they overlap with NAA boundaries. Generally, areas will find that the estimates available in the NEI will suffice for providing a reasonable estimate of these emissions, with the purpose of providing a general id ea of the level of contribution to the overall emissions within the NAA.
Wildland fires ( WLFs ) are generally defined as any non

- structur e fire that occurs in the wild land (an area in which development is essentially non

- existent, except for roads, railroa ds, power lines, and similar transportation facilities)

. The National Wildfire Coordinating Group 26 has identified the following two types of WLFs 27 :

 Prescribed fire: Any fire ignited by management actions to meet specific objectives ( generally related to the reduction of the biomass potentially available for wildfires )

. A written, approved prescribed fire plan must exist, and National Environmental Policy Act requirements must be met (where applicable) prior to ignition.

 Wildfire : An u n planned, unwanted W L F including unauthorized human

- caused fires, escaped WLF use events, escaped prescribed fire projects, and all other WLFs whe re the objective is to put the fire out.

Wildland fires are a unique source of emissions with respect to NAAQS attainment planning

. For ozone, PM 2.5 , and regional haze planning purposes, t hese fires are major sources of primary PM 2.5 and VOC and a moderate source of NO X . They can consequently impact the ambient PM 2.5 and ozone; however, they hav e a number of unique properties:

26 The National Wildfire Coordinating Group was formed under a cooperative agreement between the Departments of Agriculture and the Interior and consists of representatives from each of the Federal land management agencies and the National Association of State Foresters.
27 Definitions are derived from the Glossary of Wildland Fire Terminology , National Wildfire Coordinating Group , PMS 205, July 2012. Available at http://www. nwcg.gov/pms/pubs/glossary/p.htm

.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

82  Depending on the fuel source and acreage burned, b oth prescribed and wildfires can emit significant emissions, but emissions from prescribed fire s are generally lower due to the burning characteristics and the relative amounts of flaming and smoldering emi ssions

. In addition,
p rescribed fires can be used to prevent future wildfires, which are generally larger, hotter, more dangerous, and more polluting

.

 Wildfires are naturally occurring events for which the emissions are generally not reasonable to prevent or control

. As such, air agencies may request that the EPA exclude from regulatory determinations ambient data influenced by the wildfire if the request meets the criteria, schedule, and procedural requirements for an exceptional event set forth in 40 CFR 50.14. 28

 Fire emissions can rise very high in the atmosphere on plumes , and the pollutants can be transported beyond state boundaries

. Fires occurring outside NAA s can have impacts within NAA s on days that may not be determined to be exceptional events.

 Sin ce wildfires and prescribed fires generally occur in forests and rangelands, they are less likely to be within the boundaries of NAA s, which are usually urbanized areas.

 Fires can also reduce ozone formation because their smoke can block sunlight that othe rwise would result in more ozone.



### 4.9 Quality Assurance As part of the 8

- hour ozone NAAQS, PM 2.5 NAAQS, and regional haze rule s , state , local and tribal agencies are strongly encouraged to perform QA checks and procedures on their inventories

. State, local and tribal agencies can develop and select the QA procedures they will perform, and should include the details of their QA program (including specific procedures) in their IPPs.
The purpose of QA is to ensure the development of a complete, acc urate, and consistent emissions inventory

. A well

- developed and well

- implemented QA program fosters confidence in the inventory and in any resulting regulatory and/or control program.
When air agencies are using data from the NEI, additional QA is warranted considering the purpose for SIPs is not the purpose for which the NEI was developed. Since a great deal of QA is done on the data used for the NEI, must of the QA work has been done and so starting with the NEI can often save time.
The overall QA program provides routine and consistent checks and documentation points in the inventory development process to verify data integrity, correctness, and completeness; identifies and reduces e rrors and omissions; maximizes consistency within the inventory preparation and documentation process; and facilitates internal and external inventory review processes

. Quality

assurance activities include technical reviews, accuracy checks, and the use of approved, standardized procedures for emission calculations, and should be included in inventory development planning, data collection and analysis, emission calculations, and reporting.

28 “Treatment of Data Influenced by Exceptional Events; Final Rule” (72 FR 13560 , March 22, 2007 )

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83 4.9.1 QA Reference Materials and Planning The EPA has developed several g uidance documents designed to assist state , local and tribal agencies in designing and implementing their QA programs

. The EIIP Volume VI, available at http://www.epa.gov/ttn/ch ief/eiip/techreport/volume06/index.html , addresses QA issues, including the following:

 Chapter 1: Introduction

- The Value of QA/QC

 Chapter 2: Planning and Documentation

 Chapter 3: General QA/QC Methods

 Chapter 4: Evaluating the Uncertainty of Emission Estimates

 Chapter 5: Model QA Plan

 Appendix A: Example Audit Report

 Appendix B: Technical Systems Audit Checklist Example

 Appendix C: Example 1 of Data Quality Audit Checklist

 Appendix D: Example 2 of Data Quality Audit Checklist

 Appen dix E: Performance Evaluation Checklist Example

 Appendix F: EIIP Recommended Approach to Using the Data Attribute Rating System (DARS)

On October 21 2008 , the EPA issued the latest version of the EPA Quality Program Policy (CIO 2106.0)

. This policy supe rsedes the previous CIO 2105.0 (formerly EPA Order 5360.1 A2 )

. This policy established

amo ng other things, the requirement for QAPPs for all EPA

- supported programs that generate environmental data

. As described by the EPA Guidance “EPA Requirements for QA Project Plans”:
The purpose of a QA Project Plan is to document planning results for environment data operations and to provide a project

- specific blueprint for obtaining the type and quality of environmental data needed for a specific decision or use.

The orders describing the QA requirements are available at the EPA ’s website for Agency

- wide Quality System Documents ( http://www.epa.gov/quality/qa_docs.html )

. That website also includes specifications fo r non

- EPA organizations: “ EPA Requirements for Quality Management Plans ” (EPA/240/B

- 01/001; March 2001) and “ EPA Requirements for QA Project Plans ” (EPA/240/B

- 01/003; March 2001)

. Additional documentation is also available on the same website under the subheading of “General Guidance” that air agencies may find helpful in developing their own quality assurance plans for their inventory development efforts.

States should also consult with their specific regional office to determine how to meet the quality assurance planning requirements for the SIP planning inventory development.

4.9.2 Types of Problems in Emissions I nventories Emissions inve ntories are compiled from a large number of disparate data sources, which can lead to many types of data problems

. These problems can be divided into value errors and structure errors

. Value errors are errors in the values of emissions inventory data fields, such as the emissions amounts, incorrect codes, missing values that are required, or incorrect data such as facility names, stack heights, or latitude/longitude locations. Correct q uality assurance can identify these errors and allow data dev elopers to correct them before the data are used for their intended purpose.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

84 Structure errors refers to those data problems that cause databases to not work, such as missing records in relational database tables (e.g., “widows” and “orphans”) , duplicate re cords (i.e., multiple records that represent the same emissions, causing double counting), or incorrect formats (e.g., the wrong number of fields, missing fields that are required , mismatched data types , such as integer versus text )

. Data with no structure errors are described as having good “data integrity

. ” Generally, these types of problems should be automatically prevented by using robust data systems to manage the data in ways that match the expected downstream data use , but this is not always the case

. For example, data systems managing emissions inventory data should be developed with the AERR requirements in mind, since these are the governing requirements for SIP

- related inventories.

4.9.3 Checks Available T hrough the EPA’s Emissions Inventory System Whil e many inventories used for SIPs are not also submitted to the EPA through its EIS (the system the EPA uses to build the NEI), the EIS does have a large number of documented QA checks that the system performs as it is loading data submitted by air agencies

. Th is automated QA provide s a large number of data integrity checks that air agencies can consider including in their own data systems or checking as part of their inventory QA

. To access a list of these checks, EIS users must use the EIS Gateway and use the “QA Checks” link under the “Reference Data” heading on the left of the Gateway interface

. The checks are not otherwise published on the EPA ’s website and can be requested by non

- EIS users by submitting a request to the EIS Gateway access contact listed at the EIS contacts website ( http://www.epa.gov/ttn/chief/eis/index.html ) . The list has more than 600 data checks that are performed automatically by the EIS

. While many of these checks are only relevant for getting data into the EIS, they promote standardization of inventories and proper formatting in accordance with the AERR, which (as noted previously) provides the EPA’s standards for inventory preparation i ncluding for SIP inventories.
Since the timing of development of SIP inventories is rarely, if ever, coincident with the timing required for submitting emissions for the NEI, it is generally not feasible for air agencies to submit SIP inventories to EIS. However, the same types of checks can and should be done on SIP inventories to insure appropriate inventory quality.

The EIS checks include both critical errors and warnings

. Critical errors prevent data getting into the EPA data system until they are corr ected, whereas warnings allow the data to go through, but may need to be resolved to ensure the data transmitted to the EPA are correct

. Examples of critical errors include:

 Checks that data codes for required fields use valid values ( for the given invento ry year ; see also Section 4.7 )

 Fields required by the AERR and for data integrity are present

 Certain fields are within a critical range check (e.g., a year is bet ween 1900 and 2050 , stack height is between 1 and 1300 meters )

 Certain fields have appropriate lengths (e.g., ZIP codes are between 5 and 10 characters)

 Percentages are provided as percentages (1 to 100) and not as a fraction

 Data element types (e.g., inte ger, text, numerical) of required data fields are provided consistent with their required type.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

85  MOVES county database submission contains the correct files

 NMIM county d atabase submission contains the correct files

 Conflict with pollutants reported for gro uped pollutants versus individual members of the
group.

 If stack diameter information is reported, the release point exit gas flow rate or velocity should be reported. Both may also be reported.
Examples of warnings include:

 Checks that data codes for opti onal fields use valid values (for the given inventory year)

 Data value is longer than the allowable width (some text fields will be truncated if longer than what the EIS allows).

 Emissions value is outside of a presumed valid range

 Exit Gas Stack temperatu re is outside an appropriate range

 When submitting monthly data, all months are not submitted together

 File names of mobile data files use in correct file extensions

 Data element types (e.g., integer, text, numerical) of optional data fields are inc onsisten t with their required type.

4.9.4 Inventory Comparisons Inventory comparisons can be used in multiple ways to effectively identify problems in new inventories. This is most useful when a high

- quality prior inventory is already available. In states with a long hi story of developing SIPs, past inventories will be readily available for such comparisons. In states with new or emerging attainment problems, the EPA suggests comparing SIP inventories to the NEI. Even when the comparisons reveal problems not with the new inventory but with the one being compared, this can increase confidence in the inventory of interest.
Emissions are one of the obvious things to compare, and these comparisons are usually done on a pollutant

- by

- pollutant basis for pollutants important to a given analysis. As noted in the section on ranking techniques (Section 4.9.7 ), ranked emissions (e.g., facility, unit, county, SCC group) can be compared to the s ame ranked emissions from other inventories. Such comparisons will often identify differences worth further exploration when one large source appears on one list and not the other.
In addition to ranking, all records across an inventory (or inventory summary) can be compared and percent differences can be computed. This is usually done by computing “ new emissions

– old emissions ” divided by “ old emissions ” . Large or unexpected percent differences can be investigated further to make sure that the differences have some reasonable explanation, such as newer emissions being controlled, a downturn in activity for one inventory, process changes, fuel changes, or a partial or complete facility closure. In some cases, methods changes may be the reason for such differen ces, including updated emission factors or test data.
For nonpoint emissions, graphical inventory comparisons can be useful. This can be done not only using calculated perc ent differences or ranking, but also using GIS techniques to map county level emissionsEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

86 and their differences. It can be very useful to map the old emissions, new emissions, and the computed difference or percent difference side

- by

- side. This can reveal ar eas of large emissions that have significantly changed from one inventory to the next, raising questions for further exploration. When comparing to an EPA inventory that used EPA methods for a particular sector, this could reveal that the SIP planning inve ntory is a better inventory with updated methods, or it could reveal that outdated methods are being used. In any case, having made the comparison will help inventory developers understand the potential improvements that could be made or that have been mad e, which will help in understanding reviewers’ expected reactions to the data.

For multi

- state inventories needed for SIP development, state

- to

- state comparisons may be useful in addition to county maps. This is especially true if emissions for one state w ere developed differently from emissions for another state. The EPA encourages states to work together to promote consistent approaches across a multi

- state NAA, but a final QA check of the consistency can be done using the comparison techniques described here.

4.9.5 Checking Data C odes As described in Section 4.7 , air agencies should check the inventory data codes they are using against valid codes

. Valid codes are defin ed by the EPA within the EIS. Air agencies that start with the NEI may significantly minimize the burden of this recommendation.

4.9.6 Point Versus N onpoint and R econcil i ation Several quality assurance issues arise related to point versus nonpoint sources and in ventories: (1) correct identification of point sources, (2) prevention of double counting across point and nonpoint, and (3) prevention of missing nonpoint emissions.
Minimum thresholds are specified in the AERR for which sources with facility total potent ial to emit emissions above those thresholds must be treated as a point source in SIP planning inventories

. This is more fully explained in Section 2.5.7 , with low er thresholds relevant for ozone and PM NAA s

. Air agencies should implement a QA check (or otherwise have a data collection process) that ensures all facilities with potential

- to

- emit emissions (potential controlled emissions, if applicable) that are greater than these thresholds are included in their inventory as point sources

. See also Section 2.5.2 for more information on calculating potential emissions

.
When a particular type of source include s contributions from both point and nonpoint sources, double counting can occur

. QA steps should be taken to ensure that double counted emissions have been prevented

. A good example of this is smaller boilers

. Both point source facilities (based on the potential to emit thresholds) and smaller facilities are likely to have emissions from non

- industrial boilers

. For instance , some large institutional facilities such as hospitals may be included as a point source with their associated boiler emissions, whereas smaller institutional facilities are not included as point sources and would thus be included as a nonpoint source under an “institutional/commercial” boiler SCC

.
The EPA provides calculation approaches for many nonpoint emissions that allow for subtracting out the activity of the point source parts prior to estimating nonpoint emissions , including that for the institutional/commercial boiler example

. This is called “point/nonpoint reconciliation”

. WhetherEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

87 nonpoi nt emissions are estimated by the EPA or by air agencies, a n assessment of quality s hould be done to ensure that sectors associated with both point and nonpoint sources do not double count emissions . See also Section 4.8.2 for additional information on preventing double counting. A list of source sectors with potential point/nonpoint overlap is provided in Table 18 above and in the latest NEI Technical Support Document, available at http://www.epa.gov/ttn/chief/eiinformation.html

. A third type of QA should be done for categories that have both p oint and nonpoint contributions

. It involves an assessment of potentially missing nonpoint emissions

. Since the requirement for SIP inventories is to include emissions from all sources, it is not sufficient to exclude nonpoint emissions when part of a sector is covered by point sources, unless it can be shown that the nonpoint portion is negligible

. At a minimum, air agencies should consider the tools available from the EPA to estimate nonpoin t sectors (see Section 4.8.2 ) and evaluate whether or not their point source inventory covers all of the activity associated with the nonpoint categories

. For inven tory years not covered by EPA tools,

a gencies should compare point total activity as collected from point sources versus the same type of activity data used in the EPA tools

. For example, US DOE fuel consumption data can be used for industrial, commercial, and institutional boilers

. The source of the activity data used for the latest EPA nonpoint methods is included in the descriptions of those methods in the nonpoint tools described in Section 4.8.2 and with the latest NEI documentation.

4.9.7 Ranking Techniques Ranking emissions records can be a very useful tool to identifyin g value errors in emissions values or other numeric inventory data fields, or at least in finding records that need further investigation

. Ranking involves first defining a set of sources and a level of aggregation of emissions and then ordering those emissions values from highest to lowest or lowest to highest

. This analysis must be done one pollutant at a time

. An analyst then considers whether those sources at the top of the list make sense.
Point sources, facility level emissions ranking
For point sources, ranking can be done at the facility total, unit total, or process level (i.e., at the SCC level) , and each level has its place for reviewing inventories

. A facility level ranking can often be followed by subsequent investigation to understand the reasons (at the unit and/or process level) for very high or very low values

. An analyst using a ran king pro cedure would assess the facilities with the largest emissions and seek to understand whether they make sense

. For example, f or combustion products such as NO X or SO 2 , one would expect to see large EGUs and other industrial sources

. Ranking of emiss ions values is usually done for one pollutant at a time, reviewing most carefully those pollutants that are most critical to the particular purpose of the inventory

. For example, an inventory supporting ozone analysis would want to review NO X and VOC most carefully.
It can be useful to compare the list of top facilities for a given pollutant from one inventory to a previous or alternative inventory for a given state or NAA

. This can raise q uestions regarding large changes from one inventory to another, whic h could be explained (e.g., a decrease due to controls) or could identify a problem (e.g., a missing value or data entry problem)

. In addition, facility

- level ranking can useEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

88 additional grouping such as by industry code (i.e., NAICS), to identify unexpecte dly high or low emissions for facilities within a particular industry.

Point sources, sub

- facility emissions ranking

Unit

- and process

- level summaries can additionally be ranked for more specific analyses

. For example, all boilers could be ranked and parti cularly high or low emissions values investigated

. Similarly, all natural gas processes at particular unit types (e.g., boilers) or by industry (NAICS) could be ranked

. These rankings can show real variations, but they can also find incorrect values that s tand out when ordered and reviewed in this way

. There are many variations that could produce useful results, and which ones are useful for a particular inventory depends on many factors and the purpose of the inventory.

Nonpoint and mobile source ranking

N onpoint and mobile emissions can also be ranked as technique to help with QA

. Since these inventories are primarily compiled at the county/SCC resolution, the ranking can be done only at combinations of county, SCC, and for specific pollutants

. Total county nonpoint emissions could be ranked to look for overly high or low values, but the same effect can be accomplished in a visual way with mapping approaches (see Section 4.9.9 )

. Specific SCCs can also be selected and the emissions by county ranked, or individual counties selected and SCCs ranked and compared to other counties.
Since nonpoint emissions are based on various types of activity data that also h as a county or other spatial resolution (such as census tract), these activity data can be used to “ normalize” the nonpoint emissions prior to ranking

. For example, emissions coming from households (e.g., residential heating, residential wood combustion, c onsumer solvents) can be divided by population or housing data and ranked for identify possibly strange results

. Since some of the activity data used for these categories starts with state or regional resolution and is subdivided to apportion to the county resolution, such comparisons can reveal illogical outcomes of such approaches

. For example, while it makes sense that residential wood combustion occurs more per household in rural areas, it wouldn’t make sense for a very low population county to have a d ispr oportionate amount of emissions and urban areas have none.

4.9.8 Outlier Analyses One result of the ranking approaches described above will be to identify outliers

. However, such ranking is a relatively unsophisticated way of identifying such outliers

. A mor e robust approach can be used for point sources where states have the underlying activity data reported by facilities on a per

- process basis

. Dividing emissions by activity values would produce a set of implied emission factors, or rates. The rates for a s imilar set of processes (based on SCC) and control devices in use might be expected to be within an order of magnitude of each other. Emission rate values that are too far outside the expected relationship could be further investigated to better understand the source of any unexpected values, which might include an error in the units of measure or the presence of controls or an incorrect SCC, as well as data entry errors for emission values or other related fields.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

89 4.9.9 Using Maps to QA Nonpoint Emissions Nonpoint and mobile source emissions data are associated with states and counties and therefore are ideal candidates for mapping with GIS software

. By mapping emissions values for individual SCCs or groups of SCCs, data analysts can identify unexpected pat terns in the data that could signal an error in creating the data

. Though it is technically more challenging to use GIS software, this approach can often be more valuable than ranking in identifying data problems.
Like the ranking techniques, GIS maps can also use emissions data normalized by some other underlying or related spatial data, such as population, land use, urban/rural designations, or housing

. This type of information is increasingly available online from the U.S. C ensus B ureau and other sources

. Data analysts can use the other data to identify unexpected relationships that possibly indicate bad assumptions made in the underlying methods.

4.9.10 Expected Pollutants A ir agencies can use their expertise with emissions sources to identify which pollutants are expected from particular processes

. For example, NO X is always expected as a by

- product of combustion
processes

. Conversely, analysts can identify pollutants that are not expected from a particular process, such as SO 2 from an evaporative process

. Once identified, such lists can be used to cross

- check inventories to identify either problems with reported emissions, pollutant codes used, or process codes used

. For example, if a combustion process doesn’t have NO X emissions, it could be that the wrong pol lutant code was used in reporting the NO X and it’s showing up as something else

. Or, the process itself may be incorrectly using a combustion process code.
Expected pollutants can also help with making sure the correct PM components are provided for PM inv entories, in particular that condens a ble PM emissions are included in the total PM emissions and that both filterable and condensable PM emissions are reported

. This issue was described in Section 4.2.1 along with a list of the types of sources expected to have such emissions.
Some emissions data analysts may not be familiar with various sources enough to know which pollutants should be expected

. For point sources, a gency staff can rely on the sum total of all reported data across multiple sources for a particular process to get a good idea of what should be expected

. For example, if all but one industrial boiler burning natural gas reported VOC, then it would be wort h further investigation as to why VOC was not reported for that one

. Since the AERR specifies that all criteria pollutants must be reported if any one pollutant exceeds the potential to emit threshold, one should expect that similar processes from multiple facilities would have many, if not all, the same pollutants.
There are other ways to identify expected pollutants

. These include looking at past inventories created by the same air agency or looking at the NEI

. Another way is to see what emission factors are available for the process in Webfire

. While these are not foolproof ways of finding expected pollutants, they can be very helpful

. Comparing a draft inventory with such a list can also identify unexpected pollutants to consider

. Used with ranking techn iques, knowing what pollutants are expected can also help when you find zero or null values for a facility, unit, or process.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

90 4.9.11 Facility and Release Point Locations Facility and release point (e.g., stack) locations are key elements of inventories that are u sed primarily in preparation of inventories for air quality modeling and also in permit modeling

. Facility locations are also used in mapping point sources for various public communications purposes and to help understand the nature of air quality problems influenced by local sources . While facility resolution is acceptable for many modeling applications, including 12

- km gridded modeling, the need for release point locations increases for finer resolution modeling. Thus, for 4

- km or 1

- km modeling, release p oint location information should be considered.
With regard to the more detailed release point coordinates, the EPA recognizes the need for air agencies to leverage SIP inventory development efforts for possible use for other inventory needs. Thus, air
age ncies should be particularly attuned to release point geographic coordinates for sources that could be involved in permitting or risk analysis. For regulatory dispersion modeling, release point location is critical (rather than only facility location).

The EPA’s EIS and other inventory data systems support two types of locations: facility and release point

. There are four key errors that can occur, and each can be identified with their own type of check, as listed below.

 Facility is not consistent with the state/county FIPS code This error can be found using GIS , SAS ® or other calculations to compare the latitude/longitude location with the county boundaries using some tolerance

. Because county boundaries have varying degrees of accuracy, a tolerance should be used that allows for locations near, but not always 100% within, county boundaries.

 Facility location is not consistent with the physical location of the facility Since some facilities can be on very large tracts of land, facility locations developed us ing geocoded addresses or facility entrances are often not accurate with regard to the actual location of the facility

. For emissions inventory purposes, the EPA encourages that facility locations be positioned on top of a part of the facility that emits o ne or more pollutants , and the facility centroid is often sufficient for doing so

. Using freely available mapping software such as Google Maps, latitude/longitude locations can be plotted on satellite images to ensure that values are on top of an emitting source and not on the road, at the corporate headquarters, or in some other invalid location.

 Release point location is not consistent with facility location This check is only useful once th e facility location is accurate

. Such an error can be found using GIS, SAS® or other calculations to determine the distance between the facility location and the release point locations

. Alternatively, a subtraction of the absolute values of the latitudes and longitudes can be used to determine the difference in degrees

. If that linear distance or the distance in degrees is greater than some preset criteria, th e n the locations can be investigated further

. For some types of facilities such a s refineries or major chemical complexes, the facilities may be very spread out an d therefore may have legitimately large distances between release points.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

91  Release point location is not consistent with the physical location of the release points For many applications, even including some SIP modeling applications, all release points usi ng the same (usually facility) latitude/longitude is sufficient

. However, with the availability of inexpensive GPS technology, it is more realistic for facilities to collect and submit individual release point location information

. Furthermore, for some ty pes of analysis, particular fine scale modeling for permitting and risk analysis, correct release point locations can make the difference between a good analysis and a useless one

. It is very difficult to check the accuracy of release point locations, but using mapping software overlaid on satellite images can provide some sense of whether the release points are meaningful or not

. Coordinates reported to one

ten

- thousandth of a degree (four digits after the decimal point) give a precision of approximately 3 0 feet. Thus, a simple check to see if such values are useful is to examine the number of decimal places included in a given database.
Since a facility’s location is not likely to change, the EPA has implemented a procedure in the EIS that allows latitude/longitudes to be locked, meaning that they cannot be changed accidently during a data exchange with a state

. We encourage air agencies to implement a similar approach in their data systems so that the efforts of QA done on one invento ry can be inherited by other inventories created by that
agency

. Locking mechanisms prevent the data from being changed inadvertently through a new data collection that relies on data from an unverified data source. Thus, a comparison of the locations used in the SIP inventory to any locked and verified site coordinates in EIS would also highlight potential errors for resolution.

4.9.12 Release P oint P arameters Like release point locations, release point parameters (also called stack parameters) are key elements o f inventories that are used primarily in preparation of inventories for air quality modeling

. The release point parameters impact the modeling of emissions from facilities because they specify details of the way the emissions are released; for example, the y specify how high off the ground the pollutants are emitted and the exit velocity and temperature of those emissions

. One basic and important distinction for release points is whether the release point is a stack or a fugitive emissions, and different typ es of parameters are specified for stacks than for fugitive emissions sources.
Correct release point parameters for stacks are important for modeling done for Ozone and PM 2.5 modeled attainment demonstrations as well as modeling done for Regional Haze SIP s , whereas fugitive release parameters are not as critical for that purpose

. This is because stack emissions parameters impact the modeling of plume rise and therefore determine how high the emissions rise in the modeled layers of the air quality model

. Fu gitive emissions are emitted in the modeled surface layer with no additional characterization

. This is in contrast to more detailed plant

- level modeling (i.e., done for permit modeling or risk modeling purposes), where b oth stack and fugitive parameters ar e critical. Because the focus of this document is on SIP purposes, we focus on stack parameters here.
Stack parameters included in the EIS and historically are stack height, stack diameter (at the exit point of the emissions), exit gas velocity, exit gas f low rate, and exit gas temperature

. Additionally, a release point type is available in the EIS to specify a code for whether the “stack” has a particular orientation ofEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

92 vertical, horizontal, goose neck, vertical with rain cap, or a downward facing vent

. Va lid release point codes are available in the EIS reporting code tables in the EIS Gateway.
QA for stack parameters can be done using several of the QA methods already described

. Range checks can be applied ; these can be the default EIS range checks (see Se ction 4.9.3 ) or range checks developed by a n air agency

. A more robust range check could be developed for specific types of processes associated with a release point or for specific NAICS codes

. For exam ple, one would expect higher stacks for EGUs than for lumber mills

. Additionally, ranking techniques can be applied to stack parameters (see Section 4.9.7 ), includi ng options for grouping ranked stack parameters b y facility, unit, process and/or specific types of facilities, units, or processes

. This is somewhat complicated by the fact that multiple units or processes can feed a given release point, and when this hap pens, the predominant unit or process could be used for grouping purposes

. Finally, more sophisticated outlier analysis could additionally be used, by finding correlations between stack parameters such as height and diameter and investigating those combina tions that statistically fall outside an expected relationship or ratio.

4.9.13 Biogenic QA/QC Biogenic emissions are somewhat more challenging to QA than emissions for other source categories because they may be generated differently (i.e., as part of a gridded, hourly modeling exercise rather than more basic inventory development techniques). The following list provides some basic checks that can be done as part of the generation of biogenic emissions:

1. Check the biogenic emissions tool logs for warnings/errors.

2. Check the logs to confirm that the expected inputs were used

.
3. Compare state or county total emissions to another year or case ’s biogenic emission totals.

4. Ensure that summer emissions are greater than winter emissions

. This can be done by summing the emissi ons across the modeled summer days (e.g., May

- October) and for the other models and then comparing the totals on a state and/or county basis

. As a quick (but less rigorous) check, example summer hourly or daily emissions can be visually compared to example winter hourly or daily emissions using software that displays the gridded emissions.

5. Visually inspect sample days of the gridded, hourly emissions using software that displays the gridded emissions

. The VOC emissions should generally be higher in southern latitudes because of warmer temperatures

. This difference should be more pronounced in winter in cases where the southern areas have more actively growing vegetation

. The NO emission should generally be higher in agricultural areas with signi ficant fertil izer application.

4.9.14 Timing of QA and F ollow

- up As air agencies , as well as the EPA regional offices, work quickly to meet relevant inventory and SIP deadlines, data problems are exacerbated when they are discovered too late in the process

. A key part of making sure that a QA plan is effective is deciding (as part of the planning) when a given QA check is to be done and ensuring (as part of implementing that plan) that it is actually done

. To do thisEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

93 effectively, QA steps should be timed in a QA plan at th e earliest possible time that the step can be performed so that errors are caught as early in the process as possible

. Furthermore, assurances must be put in place that someone is confirming that the checks have been done along the way, so that errors get caught

. At the end of the data development process, some accounting for the history of the QA should be available along with the data, so that others can confirm that the checks have been done and can be reassured

. Where possible, evidence of completion of each QA step should be referenced, such as a comparison report.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

94 

## 5 Developing Projected Emissions Inventories

5.1 Projected Emissions Overview Emissions estimates for future years 29 are called “emissions projections” or “projected emissions

. ” These projections in clude emissions growth (due to increased or decreased activities) and emissions controls due to regulations, settlement agreements (or con s ent decrees), fuel

- switch es, or other programs that reduce emissions in specific ways in the future

. For point source s, emissions projections can also include facility and/or unit

- level shutdowns due to settlement agreements ( or consent decrees) and/or ownership decisions.
The primary goal in making projections is to obtain a reasonable and technically credible estimate of future

- year emissions that accounts for key variables

. The EPA encourages the air agencies to incorporate in their analys es the variables that have historically been shown to drive their economy and emissions, as well as the changes in growth patterns and regulations that are expected to take place between the time of their base year and projected attainment year

. For details on which future year(s) should be modeled for attainment demonstrations, readers should refer to the Modeling Guidance ( http://www.epa.gov/ttn/scram/ guidance_sip.htm ).

The EPA’s latest projection approaches and data are available as a part of the EPA ’s “ emissions modeling platform” development

. These platforms are released and updated periodically in accordance with the EPA regulatory and analysis activity on the Emissions Modeling Clearinghouse at http://www.epa.gov/ttn/chief/emch . While each platf orm comes with a single or limited set of future years included, the data and thoroughly documented approaches can help air agencies to develop and improve their own emissions projections.
While dated, the 1999 EIIP report entitled “Procedures For Preparin g Emissions Projections” ( http://www.epa.gov/ttn/chief/eiip/techreport/volume10/x01.pdf ) introduces the basic concepts behind emissions projections issues and approaches. T he co ncepts of control efficiency, capture efficiency, rule effectiveness, and rule penetration were introduced in Section 2.5.18

. The EIIP document provides information on how to use these factors to estimate projected emissions

. However, some key features of this document need to be updated, including the reference to the Econ omic Growth and Analysis System , which is no longer supported by the EPA

. Other outdated concep ts include the assumption that economic growth can be a good indicator of emissions growth

. While some correlation can exist, it cannot be assumed but rather must be demonstrated for a particular industry or facility. The correlation has not been well obse rved historically in the NEI data because of various issues including technology improvements and fuel

- switching that often reduce emissions without regulation

.

29 Technically, projected emissions could be made from a base year to a year that has already occurred when data are not yet available for a very recent year. However, for the purposes of the remainder of this guidance, we will assume projected emissions refers to future year projected emissions.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

95 In this section, we will address an overall approach for tackling emissions projection issues t hat incorporates use of this document and points out where other approaches or new data are available to amend the information included in that report.

The EPA recommends that d evelopers of project ed emissions take the steps in the bulleted list below. Eac h of these steps corresponds to a subsequent subsection.

 Identify sectors of the inventory that require projections and sectors for which projections are not advisable, and prioritize these sectors based on their expected impact on the modeling region (Sec tion 5.2 ).

 Collect the available data and models that can be used to project emissions for each of the sectors (Section 5.3 ).

 For key sectors, determine what information will impact the projection results the most, and ensure that the data values reflect conditions or expectations of the inventory region (Section 5.4

.

 Quality assurance (Section 5.5 )



### 5.2 Identify and Prioritize Key Sector s and Regions for P rojections Emissions data developers should evaluate their inventories for those sectors and regions that are most critical to their modeling results

. The purpose of identifying these key sectors is to direct more resources and efforts t o estimating future

- year emissions for these sectors in the subsequent steps.
Sectors can be subsets of the larger groups of stationary area, on

- road mobile, nonroad mobile, and point sources

. For ozone modeling, it will be most important to ensure correct projections for sectors with higher NO X emissions . In larger urban areas that contain VOC

- limited regions, sectors with higher VOC emissions will also be important

. Mobile sources are typicall y large contributors to both VOC and NO X ; therefore, they are usually a priority in estimation of future

- year emissions, particularly for urban

areas

. For PM and regional haze modeling, the relative importance of primary PM 2.5 emissions and its
precursors will depend on the area of the country

. Primary PM 2.5 emissions may be important in urban areas or areas heavily influenced by local sources such as residential wood combustion or industrial facilities

. In the East, SO 2 emissions may be of primary importance

. For PM 2.5 planning, NO X , VOC, and NH 3 will vary in importance depending on the particular situation, which needs to be assessed as part of the SIP planning process.
Emissions data developers should consider the prox imity of the emissions and the expectation of long

range transport when reviewing projection assumptions. Those emissions that have an impact on the nonattainment status (whether transported from outside areas or locally generated) should be given highest priority in evaluating the projection assumptions. For example, less priority can be given to emissions from distant states and/or for pollutants that do not transport from those states to the NAA

. In some cases, there are sectors that are very difficult o r highly uncertain to project into the future

. Wildfire emissions is a common example of such a sector, since models are not readily available that estimate the magnitude and location of future

- year emissions

. In these cases, it is reasonable to createEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

96 an “average year” inventory and temporal distribution of the emissions. Other approaches to future

year fire emissions include holding the emissions constant at the same levels as included in the base
year.


### 5.3 Collect A vailable D ata and M odels for Each Sector Ne eding P rojections For each sector needing projections (and in particular for the priority sectors), air agency staff should collect and review growth and control information

. The sources of such information depend upon the sector of interest

. Some data res ources and approaches are available and provided here, and new data and approaches will become available subsequent to the publication of this document

. The information provided here is a snapshot of information that will grow and adapt over time, and emis sions modelers should seek out such new information as part of this step.
Emissions modelers can rely on available default data for sectors and regions with lower priority for consideration (as described in the previous section)

. For sectors and regions th at are important to modeling the NAA , emissions modelers should spend additional effort obtaining improved information from other modeling applications (such as modeling done by RPOs or other state s) or developing the improved information themselves.

As me ntioned previously, the EPA provides control assumptions with its modeling data used for promulgating air quality rules and impact assessments . The EPA approaches typically include the impacts of federal rules that have been finalized. Impacts of proposed rules are rarely included, as the changes in emissions impacts can be very large between the proposed and final rules. These data are posted at the Emissions Modeling Clearinghouse at http://www.epa.gov/ttn/c hief/emch

. Sometimes, more current information is available than is available from the EPA , for example, when reconsideration amendments are developed and finalized after the EPA has publicly released its projected inventories

. In the subsequent subsectio ns, we focus on sources of growth information.

5.3.1 Stationary Sources Section 2 of the EIIP projections document gives details about projection of point

- source emissions , though a great deal has changed since 1999. One thing that has stayed the same is that t here are two major subsets of point sources: EGUs and non

- EGUs

.

T he EPA uses the IPM to model future electricity demand and emissions trading programs that now dominate the prediction of future

- year emissions from EGUs

. According to the IPM users docum ent:

“IPM is a multi

- regional, dynamic, deterministic linear programming model of the U.S. electric power sector. It provides forecasts of least cost capacity expansion, electricity dispatch, and emission control strategies while meeting energy demand and environmental, transmission, dispatch, and reliability constraints. IPM can be used to evaluate the cost and emissions impacts of proposed policies to limit emissions of SO 2 , NO X , carbon dioxide (CO 2

), mercury (Hg), and HCl from the electric power sector.”Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

97 More information on IPM is available at ( http://www.epa.gov/airmarkt/progsregs/epa

- ipm/index.html )

. Additionally, IPM

- based emissions are posted by CAMD on the EPA ’s website ( http://ampd.epa.gov/ampd/ )

.
Other EGU projection models exist and could be used for estimation of future

- year emissions

. A recently developed approach by the ERTAC benefits from an in

- depth collaboration among a la rge multi

- state region. Other examples include the National Energy Modeling System (NEMS), the Electric Power Market Model (EPMM) and the M ark et A ll ocation (MARKAL) model

. There is also a N ortheast

- specific version of MARKAL called NE

- MARKAL.

The NEMS mode l (available at: http://www.eia.gov/oiaf/aeo/overview/ ) was developed by EIA and uses Annual Energy Outlook ( AEO ) projections of energy supply, demand and prices , and it couples with regulatory/SIP and trading assumptions and known future control installations to create future year NO X , SO 2 and heat input estimates

. The EPMM is a private sector EGU model, but some discussion can be found in these reports: http://www.ladco.org/reports/rpo/emissions/ eug_growth_methodologies_methods_final_report_pechan.pdf and http://www.publicpow er.org/files/PDFs/EPRItoEPA.pdf

. The MARKAL model is a data

- driven energy system optimization model geared more towards basic, preliminary analyses of energy policies at EGUs but does not provide plant

- specific detail like IPM . MARKAL is relevant for other sectors and more information is included in Section 5.3.5

. To prevent double

- counting of emissions sources, emissions developers should be careful to match the

sou rces of emissions from external models such as IPM with the base year emissions sources

. This helps to ensure that the EGU part of the point source inventory is separated from the non

- EGU part based on the facilities included in the future

- year EGU model

. In the case of IPM, t he facilities are defined using NEEDS

. T he NEEDS records should be compared to the base year point inventory using the ORIS Plant ID field from both

. In some cases (e.g., co

- generation facilities) , only some of the units at the facilit ies are included in NEEDS ; therefore, the separation of EGUs from non

- EGUs should be done at the unit level, not by facility

. One resource for this information is also in the NEI, which contains a field that indicates whether the units are NEEDS units or n ot.
Additional considerations for projecting point source EGU emissions without the IPM model are also provided in the EIIP projection document

. However, several of the references in that document are now out of date, as follows.

 The latest SCC codes are a vailable as described in Section 2.5.14

.
 The AP

- 42 emission factor website is now http://www.epa.gov/ttn /chief/ap42/index.html

.
 The website with further information about point source inventories is http://www.epa.gov/ttn/chief/eiip/techreport/ . This guidance includes more updated information tha n the EIIP report.

 The reference in the Table 2.1

- 1 web link is no longer applicable

. Instead, the following information can be used to help provide similar information:

o Energy consumption by industry report, 2002: http://www.eia.doe.gov/oiaf/analysispaper/industry/consumption.htmlEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

98 o Annual Energy outlook report, early release 201 4 : http://www.eia.gov/forecasts/aeo/er/index.cfm

The references in Table 2.1

- 2 are also out of date and should be updated as follows:

 U

. S

. EPA Emissions trends reports

. These reports can be used to provide the historical trends of emissions sectors based on the NEI : http://www.epa.gov/air/airtrends/

 Integrated Planning Model: http://www.epa.gov/airmarkt/progsregs/epa

- ipm/index.html

 Multiple Projections System

- is no longer in use

 California Emission Forecasting System: http://www.arb.ca.gov/ei/drei/maintain/database.htm

For nonpoint sources, Section 3 of the EIIP projections document provides additional details about projecting nonpoint

- source . However, several of the references or statements in that document are now out of date, as follows.

 The web sites for SCCs, AP

- 42 emission factors, and more information about area

- source inventories are out of date

. These should be updated to the same sites as were listed in the point sources section above. Furthermore, this guidance includes more updated information than the EIIP report referenced.

 The ASEM model mentioned in Section 3.2 of the EIIP projection document was not completed

an d is not available.

 The references in Table 3.1

- 2 are out of date and should be updated as follows:

o U

. S

. EPA Emissions trends reports

. These reports can be used to provide the historical trends of emissions sectors based on the National Emissions inventory : http://www.epa.gov/air/airtrends/

o Multiple Projections System is no longer in use

o California Emission Forecasting System: http://www.arb.ca .gov/ei/drei/maintain/database.htm
Since 2006 (EPA, 2006 a ), the EPA has been assuming that emissions growth does not track with economic growth for many stationary sources (both point and nonpoint)

. This “no

- growth” assumption is based on an examination of historical emissions and economic data

. E mission s (as of 2005) had declined for several years and those reductions could not be directly attributed to specific control
program s despite increasing economic

- based growth factors for many metrics over the sam e time period

. While the EPA continues to work toward improving the projection approach in its own work, we are still using this no

- growth assumption for many emissions sectors

. O f course, where air agencies have better data about the expected growth in em issions or the possibility of sources reaching their permit limits, that information should be included in developing more refined emissions projections.

The EPA creates and uses data that quantify assumed base year growth (projections), controls, settleme nt agreements (or consent decrees ) , and other unit and facility

- specific information on non

EGU point and stationary area sources

. These are included in the most recent emissions platform Technical Support Document (TSD) available at the Emissions Modeling Clearinghouse. The TSD s include the methodologies and background information for projecting sources such as Portland Cement, oil andEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

99 gas, industrial/commercial/institutional boilers, residential wood combustion, agricultural sources , fuel sulfur rules, co rn and cellulosic ethanol and biodiesel plants, and several other categories

. In addition, the EPA encourages air agencies to consider the latest settlement agreements and consent decrees that are updated periodically by the EPA ’s Office of Enforcement and Compliance Assurance (OECA) at: http://www.epa.gov/enforcement/

.
The tools and data sources described in S ection 5.3.5 below should also be considered for use for projection of point and nonpoint stationary source emissions.

5.3.2 On

- Road Mobile Sources As described in Section 4.8.3 , f or all states but California, on

- road mobile emissions should be estimated with the latest EPA on

- road mobile model, MOVES, following the EPA’s latest guidance available at http://www.epa.gov/otaq/models/moves/index.htm#sip

. For California, the latest EPA

- approved version of EMFAC sh ould be used.
Emissions preparation with MOVES for projected emissions is much like prepara tion for a base year. MOVES includes assumptions about emissions reductions associated with national emissions programs including the effects of national vehicle and fuel standards. Some MOVES inputs, such as meteorology, should be the same as for the bas e year inventory. Others, such as VMT and vehicle population should be grown/reduced to reflect expected changes in population and activity. MOVES default estimates for future VMT and vehicle population are based on national growth rates and should not be used for SIP inventory purposes because growth rates vary substantially from county to county.
Because of the change to the using the MOVES model and the newer guidance provided on the OTAQ websites, the EIIP projections document is no longer relevant for on

- road mobile sources.

5.3.3 Nonroad Mobile Equipment Section 5 of the EIIP projections document provides details about projecting nonroad mobile sources

. While some information is still valid, s everal of the references or statements in that document are now out of date, as follows.

 The name “ Office of Mo bile Sources ” has changed to “ OTAQ ” and it’s primary website is http://www.epa.gov/otaq/index.htm

.

 The EPA’s NONROAD model has been completed and has been used in a variety of ways by the EPA , states, and local agencies

. The website for the NONROAD model is http://www.epa.gov/otaq/nonrdmdl.htm

.

 NMIM , a free, desktop application has been developed by the EPA to help configure inputs and develop emissions inventories for the nonroad mobile sector

. NMIM is available at: http://www.epa.gov/otaq/nmim.htm

.

 Acco rding to a California Air Resources Board website, category

- specific inventory models and methods have replaced most uses of California’s OFFROAD model

. The information on California’s nonroad emissions is available at http://www.arb.ca.gov/msei/categories.htm#offroad_motor_vehicles

.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

100 Emissions preparation with NONROAD or NMIM for projected emissions is much like preparation for a base year

. N ONROAD includes assumptions about emissions reductions associated with national emissions programs

. NONROAD also includes assumptions about national growth in nonroad activity and equipment population. Local estimates of future activity and equipment popul ations should be substituted for the national estimates when possible.

5.3.4 Other Nonroad Mobile Sources Aircraft, l ocomotives, and CMV sources of emissions do not have a specific model designed for projections, and so additional effort is needed for these thre e inventory components.
For aircraft emissions, FAA data can be used to estimate growth for aircraft emissions

. The FAA provides summary historical and forecast statistics on passenger demand and aviation activity at U.S. airports

. The summary level foreca sts are based on individual airport projections

. The Terminal Area Forecast (TAF) includes forecasts for active airports in the National Plan of Integrated Airport Systems (NPIAS)

. The TAF system can be accessed at https://aspm.faa.gov/main/taf.asp

. The TAF system allows users to create their own forecast scenarios

. The TAF database, which contains a query data application, allows the public to access and print historical and forecast (up to 20 4 0) aviation act ivity data by individual airport, state or FAA region

. Air agencies can use this information to adjust their base year emissions based on projected airport activity.
For locomotives and marine vessel emissions, the best source of data on the impact of nati onal rules from OTAQ is the websites provided for each of the rules and their associated Federal Register notices

. As described for the base year emissions in Section 4.8.5 , the locomotive marine rule information is included at the website http://www.epa.gov/otaq/nonrdmdl.htm#otherref

. For CMV sour ces, Table 21 (from the base year emissions section) provides a good list of individual rules and references

. Since each rule is different, there is no single guidance that can be made about how these should be incorporated

. However, the EPA incorporates these data into their modeling platforms, and the most recent projection methodologies are documented in the TSDs included with the modeling platforms o n the Emissions Modeling Clearinghouse at http://www.epa.gov/ttn/chief/emch

. Additionally for C3 vessel s, emissions data are available from an Emissions Control Area

- International Maritime Organization (ECA

- IMO) project

. These emissions are available at a fine

- grid resolution and are subject to various engine and fuel standards in the future. Like base year emissions, air agencies should consider the state versus federal waters when deciding what parts o f the ECA

- IMO data to use (see Section 4.8.5.2 ). Growth/control factors have been developed for this C3 CMV inventory
, and the EPA is using them for future year C3 CMV inventory development

. The ECA

- IMO rule for C3 CMV can be found
at http://www.epa.gov/otaq/oceanvessels.htm

. New approaches are likely to develop over time, and so air agency staff should consult t he web pages listed here for the latest available information

. The latest EPA modeling platform projection methodology for C3 marine emissions is also available in the latest emissions modeling platform TSD at the Emissions Modeling Clearinghouse mentioned previously

.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

101 5.3.5 Other Projection Resources In addition to sector

- specific resources, there are other sources of information that projection developers can use for more than a single sector as information to help determine the most applicable growth rates for the modeling region

. These include the Bureau of Labor Statistics “Employment Outlook”, Census Bureau data, Trade Organizations and individual facilities, and the Chemical Economics Handbook

. The following paragraphs provide a brief description and additi onal references for each of the sources of data just listed.
Sources for EPA nonpoint methods

As described in Section 4.8.2 , the EPA develops methods for numerous nonpoint methods

. Each of these methods depends on some surrogate activity

. Many of these activity sources come from U.S. Department of Agriculture ( USD A ) , DOE, and Department of Labor databases available online

. Appendix B provides a list of nonpoint sectors and associated activity reports and websites

. These dat a do not include future

- year projections, but may include newer information than were used for estimating the base year information

. As such, these data can help with understanding the possible changes in activity (and perhaps emissions) from the date of t he underlying base year activity data to the present day

. It should be noted that emissions for one year (e.g., 2011) may be estimated using activity data from a prior year (e.g., 2009) because of timing needed for preparing the data does not match with the timing of the release of the underlying data

. When emissions are estimated using data earlier than the emissions base year, it further strengthens the benefit of newer activity data

. Furthermore, these datasets often include historical trends, which c ould be of use in understanding what may happen in the future.

REMI
The Regional Economics Model, Inc. (REMI) model provides a private

- sector resource to forecast industry changes into the future

. It includes aspects of four major economic modeling appr oaches: i nput

- o utput, g eneral e quilibrium, econometric, and economic geography. The REMI integrated modeling approach builds on the strengths of each of these approaches

. It attempts to reflect the idea that changes that affect industry sectors that are hi ghly interconnected to the rest of the economy will often ha ve a greater economic impact than other industries

. Free online webinars are available that provide an overview of REMI’s economic impact models including a live demonstration and question/answer period

. More information is available on the REMI website at http://www.remi.com/the

- remi

- model

.

EMPAX

- CGE
Another private

- sector tool, t he Economic Model for Environmental Policy Analysis

- Computable General Equilibrium (EMPAX

- CGE) is a regional economic model designed to estimate regional macroeconomic impacts of environmental regulations on the U.S. economy

. EMPAX

- CGE is useful for evaluating the linkages between various sectors of the economy (i.e., industries, household, trade) that result from environmental regulations and their associated compliance costs

. More information on the EMPAX

- CGE economic model is available at: http://www.epa.gov/ttn ecas1/EMPAXCGE.htm

.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

102 MARKAL

The MARKAL model is a public sector, data

- driven, energy

- system optimization model

. A user inputs the structure of the energy system to be modeled and data to characterize each of the technologies and resources included in the model run

. MARKAL calculates the least cost set of technologies over time to

s atisfy specific demands, using linear and mixed

- integer linear programming techniques

. Outputs of the model include the technological mix at intervals in the future, energy deman d, and estimates of criteria and GHG emissions, among others

. The U

. S

. DOE uses MARKAL for its System for the Analysis of Global Energy Markets (SAGE) model. SAGE is used to produce EIA’s annual International Energy Outlook.

The EPA has applied MARKAL for technology and emissions evaluations , which required the development of the U.S. EPA MARKAL technology database (EPANMD). This technology

- rich database represents the major sectors in the U.S. energy system, including the commercial, industrial, residentia l, transportation, and electricity generation sectors. The U.S. DOE’s AEO and the NEMS were used to construct the energy supply, demand, and technology characterizations. Data for technologies not represented in the AEO and NEMS were derived from other wid ely recognized authoritative sources (e.g. Electric Power Research Institute’s Technical Assessment Guide and DOE’s Office of Transportation Technology’s Quality Metrics report). More information on the EPA ’s use of MARKAL and the EPANMD can be found at http://www.epa.gov/nrmrl/appcd/climate_change/markal.htm and EPA report number NRMRL

- RTP

- 375 (EPA, 2006b)

. Control Strategy Tool (CoST)

The purpose of CoST is to estimate the emission reductions and engineering costs associated with control strategies applied to point, nonpoint , and mobile sources of air pollutant emissions to support the analyses of air pollu tion policies and regulations. Control strategy results can be e xported to CSV files or viewed in a graphical table that supports sorting, filtering, and plotting. The results can also be merged with the original inventory to create controlled emissions inventories that can be exported to files that can be input to the emissions model SMOKE

. CoST allows for user

- supplied control measures data, provides tracking of analyses and outputs, and supports built

- in quality assurance

.
The Control Measure dataset focuses on criteria pollutants and their precursors, and it includ es primary control efficiencies , co

- pollutant control efficiencies, and control costs

. The data also includes an extensive set of mobile source control measures

. More information on the Control Measure dataset and CoST is available at http://www.epa.gov/ttn/ecas/cost.htm

. Annual Energy Outlook
The EIA’s AEO forecast data was a primary input for the final version of EGAS

. However, with EGAS no longer being supported by the EPA , the latest versions of the AEO are the best available source of socioeconomic forecast data for many industrial sectors

. The latest AEO data are available at: http://www.eia.gov/forecasts/aeo/er/index.cfm

.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

103 Census Bureau

Th e U

. S

. Census Bureau provides data on total employees, total payroll, number of establishments, and value of shipments by NAICS code (2 digit

- 6 digit) for specific years

. This database is ideal for examining changes in the number of establishments betwee n the two latest available years and also for historical changes

. However, it does not provide data beyond the current year (and sometimes not even that recent) so its trend information is limited to these three “snapshots

. ” Therefore, these data are usefu l primarily to evaluate emissions changes from the base year to the present (or most recently available year) and comparing to the data included in the AEO. The census data are available at http://www.ce nsus.gov/2010census/data/

. Trade Organiza tions and individual facilities
Trade organizations can also be a helpful resource because they often have projections for future

- year growth of their industry and may be aware of pending facility closures or new facility construction

. This resource is most relevant for large industrial sources that usually are included in point source inventories

. In addition, emissions modelers should consider contacting large sources of emissions in their modeling region for the ir expectations of emissions growth or reduction

. In many cases, large industries may be willing to provide such information when presented with what will be used if no additional information can be provided

. Additional information may be found in permit a pplications for future development or controls at individual facilities. Except in the case of permit applications , emissions projections developers should be aware of possible conflicts of interest for this source of information . For example, industry gro ups or facilities may have an incentive to under

- represent future

year emissions in hopes of avoiding additional requirements for reducing emissions. However, many industrial representations have been valuable stakeholders who are interested in providing a ccurate information.

Chemical Economics Handbook
The Chemical Economics Handbook, produced by SRI Consulting (a part of IHS, Inc

. 30 ) , is a series of reports on prices, production and consumption of hundreds of chemical industry products and commodities

. Past and current information on chemical products and commodities is available, and projections of future prices, production and consumption are often available

. Reports on specific industries are also available

. Reports at an industry level can often be u sed to verify the efficacy of future industry modeling results

. Each report is updated every 3 years

. Projections, some up to 5 years from the current day, are often prepared using proprietary methods

. Reports are available by subscription, and can be obta ined as hard copy, CD, or at http://www.sriconsulting.com/CEH/Public/index.html

.

30 A number of other industry reports appears to be available from the IHS home page from the “Industries” tab. Some of these websites appear to have databases available for a fee, but they have yet not been assessed by EPA for applicability to emissions projections.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

104 

### 5.4 Evaluate and Refine Data for Projections in Inventory R egion For key sectors, emissions projections developers should determine what information will impact the projection results the most, and ensure that the data values reflect conditions or expectations of the modeling region

. The key information is identified based on a combination of base

- year emissions data and growth and control rates

. An iterative process is helpful to complete this step, as follows:

1. Estimate future

- year emissions by combining the base

- year emissions with the projection information (as described in the EIIP document referenced in Section 5.1 )

. 2. Review future

- year emissions data to identify large sectors of key pollutants (e.g. NO X , SO 2 , PM 2.5 , NH 3 and VOC)

. Emissions summaries by state/SCC or state/NAICS for point sources can be helpful for this step to consolidate the data to review.

3. For the largest future

- year emissions sectors, review the growth and control assumptions, compare among all available data sources, and/or collect additional info rmation to refine the assumptions

. A representative growth rate should be identified from the available data sources and all information known about the sources and sectors

. Stakeholder review of the data can be helpful during this step; for example, an in dustrial facility with large projected emissions may be able to review the data and provide additional information (e.g., expected capacities, fuels or controls) for a more informed future

- year emissions estimate.

4. Additionally, data developers should also compare the future

- year emissions to base

- year emissions, and if economic

- based growth is used, to identify overall growth rates for industrial sectors and scrutinize excessively high growth rates, especially when associated with significant emissions.

5. Usi ng the new information, repeat step 1 and continue these steps until a satisfactory future

year projection across the entire inventory has been completed.
Emissions models (e.g., CoST, SMOKE, MOVES, NONROAD/NMIM, etc.) provide the capability to create futu re

- year inventories using base year inventories and projection information

. Emissions modelers will need to convert the projected emissions data into specific formats for input to these models

. Prior to starting this step, data developers should determine which emissions model will be used to perform the calculations and make sure that the type of information needed by the model is being collected.



### 5.5 QA for Projected Inventories As mentioned in the previous subsection, final review of the inventories is an it erative process

. During each iteration, a daptations of the methods described in Section 4.9 can be used for QA of projected emissions inventories. The following list gives examples of some of the ways of the methods for base year inventories can be adapted for projected emissions in ventories.

 The same checks used for finding structure errors for base year emissions should be used for ensuring the projected inventories use the correct structures

. The EIS checks are less relevant since projected emissions are more likely to be in a mod eling format (since they are used for modeling) than are base year inventories. Even so, data developers should make sure that dataEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

105 structure or formatting problems do not lead to incorrect emissions data being used in planning inventories or modeling.

 Lik e base year inventories, data codes should be compared to lists of valid codes

. It is just as important to have future

- year SCCs be valid as it is for base year SCCs.

 Ranking techniques can be used to identify facilities, units, and processes that have bee n grown to unrealistic values

. Ranking sources by emissions values can identify any that rise to the top of the list of largest sources without a good reason why

. Ranking techniques can also be used for projected nonpoint emissions data.

 Inventory comparis ons can be made between projected and base year inventories to help make

sure:

o Location information is consistent between base and future year (needed for modeling only)

.
o Release point parameters are consistent between base and future year

. Where controls have been added, one may expect that the release point parameters could change, for example, with higher stacks or lower exit gas temperatures. (needed primarily for modeling).

o Emissions increases and decreases at the facility, unit, and process level are consistent with what is expected.

o Emissions increases and decreases at the county and county/SCC levels are consistent with what is expected

. If certain sectors are being held constant (i.e., no better data/approaches are available), then data developers c an confirm that these sectors did not change emissions.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

106 

## 6 References Allen, D. J., Pickering, K. E., Pinder, R. W., Henderson, B. H., Appel, K. W., and Prados, A.: Impact of

lightning

- NO on Eastern United States photochemistry during the summer of 2006 as de termined using the CMAQ model, Atmos. Chem. Phys. Discuss., 11, 17699

- 17757, doi:10.5194/acpd

- 11

- 17699

- 2011, 2011.
Appel, K. W., Foley, K. M., Bash, J. O., Pinder, R. W., Dennis, R. L., Allen, D. J., and Pickering, K.: A multi

resolution assessment of the Community Multiscale Air Quality (CMAQ) Model v4.7 wet deposition estimates for 2002

– 2006, Geosci. Model Dev. Discuss., 3, 2315

- 2360, doi:10.5194/gmdd

- 3

- 2315

- 2010, 2010.

EPA, 2006 a

. Regulatory Impact Analyses, 2006 National Ambient Air Quality Standards fo r Particle

Pollution. U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, October, 2006. Docket # EPA

- HQ

- OAR

- 2001

- 0017, # EPAHQ

- OAR

- 2006

- 0834. Appendix D: http://www.epa.gov/ttn/ecas/regdata/RIAs/Appendix%20D

-- Inventory.pdf

. EPA, 2006b. Shay, C. L., S. Yeh, J. Decarolis, D. H. Loughlin, C. L. Gage, And E. Wright. EPA U.S. National

MARKAL Database: Database Documentation. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R

- 06/057, 2006.

Daniel Q. Tong, George E. Bowker, Shan He, Daewon W. Byun, Rohit Mathur, Dale A. Gillette,

"Development of a Windblown Dust Module within the Community Multi

- scale Air Quality (CMAQ) Model: Descrip tion and Preliminary Applications in the Continental United States," submitted to the Journal of Geophysical Research, June, 2011Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

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- 1 

### Appendix A 

## Emissions Inventory System

- Quick Reference How to Create County and Facil ity NO x 

### and VOC Summaries for Select Counties

Create a summary of NO X and VOC emissions BY SECTOR and COUNTY f or a group of counties 1. Select "Request Reports" from the left hand sidebar on the EIS Gateway.
2. Under the Emissions Summaries heading, select “By Geography

. ”

3. Select Report Type "County by Sector

. "

4. Click the Data Set or Selection bar

. This brings you to a “filter” that allows you to select an inventory on which to run a report

.
To find the 2008 National Emissions Inventory (NEI) , t ype in “gpr” in the s earch box under the Data Set or Selection

. Then select (click on it with the mouse) the version of the NEI you want

– f or example"2008 V 2_0 GPR" is version 2.0 of the 2008 NEI (alternatively, select your agencies’ submitted inventory or that for another state) . To find the 2011 NEI , type in “2011 NEI” and select the “2011 NEI v1 with biogenics” (for example). Other version s and inventories will be published over time, so contact the EPA at info.chief@epa.gov to ask for the name of the latest inventory released in EIS.

5. Click on the Pollutants bar to access the pollutant filter. U se the search box provided and type in “VOC” and select that resulting row for VOC (click on it with the mouse). Repeat this for NO X . Typing both filters at the same time will not work.
6. Because we are looking at counties, go directly to the C ounty filter

. DO NOT SELECT A STATE FIRST from the State filter (this will select all counties in selected states, even if you then select specific counties in the county filter)

. Use the search box in the County filter to find the counties of interest either by name or State/County FIPS code

. Select the counties of interest by clicking on those rows

. If no counties are selected , all counties will be returned.

7. Last ly , select your Sectors using the S ectors search box

. If no secto rs are selected, the report w ill be created with all sectors

. The EIS Sectors are explained in more detail in Section of the 2011 NEI Technical Support Document

. 8. Click the "Request Download" button at the bottom of the screen

. These reports are run by EIS every 15 minutes and are available under the Report Download section o n the left hand sidebar of the Gateway

.

Note: U sing the “Run Report” button will give you a faster r esponse and display the summary on the screen, but may not include all records for your report

. A warning is given at the top of the screen if the “Run Report” result is incomplete.

Create a summary of NO X and VOC emissions BY FACILITY for a group of counties

For access to the Emissions Inventory System ( EIS ) , refer to https://eis.epa.gov/eis

- system

- web

. See also Online EIS training “Reports

– May 2012” at http://www.epa.gov/ttn/chief/eidocs/training.htmlEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

A

- 2 1. Select "Request Reports" from the left hand sidebar on the EIS Gateway.
2. Under the Emissions Summaries heading, select “By Facility

. ”

3. Select Report Type “Facility”

. For more detailed (sub

- facility) da ta, you may select “Emissions Unit” or “Emissions Process .”

4. Follow Step 4 in the list above.

5. Follow Step 5 in the list above.

6. Follow Step 6 in the list above.

7. Last ly , you may refine your search even more using the optional filters of Facility Types , NAICS , or Source Classifications

. If you do not use these filters, all facilities for the selected counties that include NO X and VOC emissions will be returned in the report.

8. Follow Step 8 in the list above.Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

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## Appendix B EPA Nonpoint Methods and Associated Activity Data and WebsitesEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

B

- 1 Category Data Type Last Release Date Data Lag

(years) Report Source Link Agriculture Production

- Livestock Livestock Population Feb 2009 2 Census of Agriculture USDA http://www.agcensus.usda.gov/
Agriculture Production

- Livestock Livestock Population Continuous

Updates USDA NASS Quick Stats USDA http://www.nass.usda.gov/Data_and_Statistics/Quick_Stats/

Asphalt Paving

- Cutback Cutback Asphalt Use 2008 Asphalt Usage Survey for the United States and Canada Asphalt Institute http://www.asphaltinstitute.org/
Asphalt Paving

- Cutback VMT 2011 2 Highway Statistics 2009 FHWA http://www.fhwa.dot.gov/policyinformation/statistics/2009/
Asphalt Paving

- Emulsified Emulsified Asphalt Use 2008 Asphalt Usage Survey for the United States and Canada Asphalt Institute http://www.asphaltinstitute.org/
Asphalt Paving

- Emulsified VMT 2011 2 Highway Statistics 2009 FHWA http://www.fhwa.dot.gov/policyinformation/statistics/2009/ Aviation Gasoline Distribution

-

Stage 1 AvGas

Consumption July 2010 1.5 Petroleum Supply Annual EIA http://www.eia.gov/oil_gas/petroleum/data_publications/petroleum _supply_annual/psa_volume1/psa_volume1.html Aviation Gasoline Distribution

-

Stage 2 AvGas

Consumption July 2010 1.5 Petroleum Supply Annual EIA http://www.eia.gov/oil_gas/petroleum/data_publications/petroleum _supply_annual/psa_volume1/psa_volume1.html
Commercial Cooking Population March 2011 1.5 Population Estimates Program GCT

- T1: Population Estimates U.S. Census Bureau http://www.census.gov/popest/eval

- estimates/eval

- est2010.html

Construction Dust

- NonResidential Construction Value of Construction 2011 1 Annual Value of Construction Put in Place U.S. Census Bureau http://www.census.gov/construction/c30/c30index.html

Construction Dust

- NonResidential Construction Business Patterns 2011 2 County Business Patterns U.S. Census Bureau http://www.census.gov/econ/cbp/index.html

Construction Dust

- NonResidential Construction Construction Costs Producer Price Index U.S. Dept. of Labor http://www.bls.gov/ppi/#tables

Construction Dust

- Residential Construction Housing Units May 2011 1.5 Annual Housing Units Authorized by Building Permits CO2010A U.S. Census Bureau http://www.census.gov/const/www/permitsindex.html

Construction Dust

- Residential Construction Housing Starts June 2011 New Privately Owned Housing Units Started for 2011 U.S. Census Bureau http://www.census.gov/const/startsua.pdf

Construction Dust

- Residential Construction Ratio for 5 or more units Table 2au. New Privately Owned Housing Units Authorized Unadjusted Units for Regions, Divisions, and States 2009 U.S. Census Bureau http://www.census.gov/const/C40/Table2/tb2u2009.txt

Construction Dust

- Residential Construction Types of Foundation 2011 1 Type of Foundation in New One

Family Houses Completed U.S. Census Bureau http://www.census.gov/const/C25Ann/sftotalfoundation.pdf

Construction Dust

- Road Construction VMT 2011 2 Highway Statistics 2009 FHWA http://www.fhwa.dot.gov/policyinformation/statistics/2011/Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

B

- 2 Category Data Type Last Release Date Data Lag

(years) Report Source Link Construction Dust

- Road Construction Housing Starts June 2011 New Privately Owned Housing Units Started for 2011 U.S. Census Bureau http://www.census.gov/const/startsua.pdf

Fertilizer Application Commercial Fertilizer Usage Commercial Fertilizers Association of American Plant Food Control Officials http://www.aapfco.org/aapfcopubs.html

Fuel Combustion

- Commercial Fuel Sales 2011 2 Fuel Oil and Kerosene Sales EIA http://www.eia.gov/dnav/pet/pet_cons_821use_dcu_nus_a.htm
Fuel Combustion

- Commercial Business Patterns 2011 2 County Business Patterns U.S. Census Bureau http://www.census.gov/econ/cbp/index.html

Fuel Combustion

- Commercial Gov't Payrolls Census of Governments U.S. Census Bureau http://www.census.gov/govs/

Fuel Combustion

- Commercial Fuel Consumption 2011 2 State Energy Data System (SEDS) EIA http://www.eia.doe.gov/emeu/states/_seds.html
Fuel Combustion

- Industrial Fuel Sales 2011 2 Fuel Oil and Kerosene Sales EIA http://www.eia.gov/dnav/pet/pet_cons_821use_dcu_nus_a.htm
Fuel Combustion

- Industrial Business Patterns 2011 2 County Business Patterns U.S. Census Bureau http://www.census.gov/econ/cbp/index.html

Fuel Combustion

- Industrial Energy Consumption June 2009 3.5 2006 Manufacturing Energy Consumption Survey EIA http://www.eia.gov/emeu/mecs/mecs2006/2006tables.html

Fuel Combustion

- Industrial Fuel Consumption 2011 2 State Energy Data System (SEDS) EIA http://www.eia.doe.gov/emeu/states/_seds.html
Gasoline Distribution

- PFCs
Gasoline Distribution

- Stage 1 Business Patterns 2011 2 County Business Patterns U.S. Census Bureau http://www.census.gov/econ/cbp/index.html

Gasoline Distribution

- Stage 1 Fuel Consumption July 2010 1.5 Petroleum Supply Annual EIA http://www.eia.gov/oil_gas/petroleum/data_publications/petroleum _supply_annual/psa_volume1/psa_volume1.html Gasoline Distribution

- Stage 2
Industrial Fuel Combustion Business Patterns 2011 2 County Business Patterns U.S. Census Bureau http://www.census.gov/econ/cbp/index.html
Industrial Fuel Combustion Fuel Sales 2011 2 Fuel Oil and Kerosene Sales EIA http://www.eia.gov/dnav/pet/pet_cons_821use_dcu_nus_a.htm

Industrial Fuel Combustion Energy Consumption June 2009 3.5 2006 Manufacturing Energy Consumption Survey EIA http://www.eia.gov/emeu/mecs/mecs2006/2006tables.html

Industrial Fuel Combustion Fuel Consumption 2011 2 State Energy Data System (SEDS) EIA http://www.eia.doe.gov/emeu/states/_seds.html
Open Burning

- Household Waste Solid Waste Generation 2011 2 Municipal Solid Waste in the United States: 2009 Facts and Figures EPA http://www.epa.gov/epawaste/nonhaz/municipal/msw99.htmEmissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

B

- 3 Category Data Type Last Release Date Data Lag

(years) Report Source Link Open Burning

- Household Waste Population March 2011 1.5 Population Estimates Program GCT

- T1: Population Estimates U.S. Census Bureau http://www.census.gov/popest/eval

- estimates/eval

- est2010.html
Open Burning

- Land Clearing Business Patterns 2011 2 County Business Patterns U.S. Census Bureau http://www.census.gov/econ/cbp/index.html
Open Burning

- Land Clearing Housing Units May 2011 1.5 Annual Housing Units Authorized by Building Permits CO2010A U.S. Census Bureau http://www.census.gov/const/www/permitsindex.html

Open Burning

- Land Clearing Value of Construction 2011 0 Annual Value of Construction Put in Place U.S. Census Bureau http://www.census.gov/const/www/totpage.html

Open Burning

- Land Clearing Housing Starts June 2011 0 New Privately Owned Housing Units Started for 2011 U.S. Census Bureau http://www.census.gov/const/startsua.pdf

Open Burning

- Land Clearing Ratio for 5 or more units Table 2au. New Privately Owned Housing Units Authorized Unadjusted Units for Regions, Divisions, and States 2009 U.S. Census Bureau http://www.census.gov/const/C40/Table2/tb2u2009.txt

Open Burning

- Leaves and Brush Solid Waste Generation 2011 2 Municipal Solid Waste in the United States: 2009 Facts and Figures EPA http://www.epa.gov/epawaste/nonhaz/municipal/msw99.htm

Open Burning

- Leaves and Brush Population March 2011 1.5 Population Estimates Program GCT

- T1: Population Estimates U.S. Census Bureau http://www.census.gov/popest/data/index.html

Paved Road Dust VMT 2011 2 Highway Statistics 2009 FHWA http://www.fhwa.dot.gov/policyinformation/statistics/2009/

Publicly Owned Treatment Works Wastewater Flow Sept 1999 Wastewater Flow Projections for POTWs and Privately and Federally Owned Treatment Works in 2000, 2005, and 2010 EPA http://yosemite.epa.gov/ee/epa/ria.nsf/vwAN/S99

- 21.pdf/$file/S99

- 21.pdf

Publicly Owned Treatment Works Wastewater Flow Ask WATERS Database EPA http://iaspub.epa.gov/waters10/query_tool.criteria?srept_no=165& branding=15
Residential Coal Coal Distribution Feb 2011 3 Annual Coal Distribution EIA http://www.eia.gov/cneaf/coal/page/coaldistrib/a_distributions.html

Residential Coal Fuel Consumption 2011 2 State Energy Data System (SEDS) EIA http://www.eia.doe.gov/emeu/states/_seds.html

Residential Coal House Heating Fuel Type Data Set

- SF 3

- Table H40 U.S. Census Bureau http://factfinder.census.gov/servlet/DatasetMainPageServlet?_prog ram=DEC&_submenuId=&_lang=en&_ts=,
Residential Distillate Fuel Fuel Consumption 2011 2 State Energy Data System (SEDS) EIA http://www.eia.doe.gov/emeu/states/_seds.html

Residential Distillate Fuel House Heating Fuel Type Data Set

- SF 3

- Table H40 U.S. Census Bureau http://factfinder.census.gov/servlet/DatasetMainPageServlet?_prog ram=DEC&_submenuId=& _lang=en&_ts=,Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

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- 4 Category Data Type Last Release Date Data Lag

(years) Report Source Link
Residential Kerosene Fuel Consumption 2011 2 State Energy Data System (SEDS) EIA http://www.eia.doe.gov/emeu/states/_seds.html

Residential Kerosene House Heating Fuel Type Data Set

- SF 3

- Table H40 U.S. Census Bureau http://factfinder.census.gov/servlet/DatasetMainPageServlet?_prog ram=DEC&_submenuId=&_lang=en&_ts=,
Residential LPG Fuel Consumption 2011 2 State Energy Data System (SEDS) EIA http://www.eia.doe.gov/emeu/states/_seds.html

Residential LPG House Heating Fuel Type Data Set

- SF 3

- Table H40 U.S. Census Bureau http://factfinder.census.gov/servlet/DatasetMainPageServlet?_prog ram=DEC&_submenuId=&_lang=en&_ts=,
Residential Natural Gas Fuel Consumption 2011 2 State Energy Data System (SEDS) EIA http://www.eia.doe.gov/emeu/states/_seds.html

Residential Natural Gas House Heating Fuel Type Data Set

- SF 3

- Table H40 U.S. Census Bureau http://factfinder.census.gov/servlet/DatasetMainPageServlet?_prog ram=DEC&_submenuId=&_lang=en&_ts=, Residential Wood Timber Output 2011 2 Timber Products Output Survey USDA http://srsfia2.fs.fed.us/php/tpo_2009/tpo_rpa_int1.php

Residential Wood House Heating Fuel Type Data Set

- SF 3

- Table H40 U.S. Census Bureau http://factfinder.census.gov/servlet/DatasetMainPageServlet?_prog ram=DEC&_submenuId=&_lang=en&_ts=,

Residential Wood Equipment Type American Housing Survey for the United States: 2009, Table 2

- 4: Selected Equipment and Plumbing U.S. Census Bureau http://www.census.gov/hhes/www/housing/ahs/ahs09/ahs09.html

Residential Wood Metropolitan Characteristics 2011 2 American Housing Survey Metropolitan Data U.S. Census Bureau http://www.census.gov/hhes/www/housing/ahs/metropolitandata.ht ml
Solvent Usage

- Other Population March 2011 1.5 Population Estimates Program GCT

- T1: Population Estimates U.S. Census Bureau http://www.census.gov/popest/eval

- estimates/eval

- est2010.html
Solvent Usage

- Other Business Patterns 2011 2 County Business Patterns U.S. Census Bureau http://www.census.gov/econ/cbp/index.html
Solvent Usage

- Surface Coatings Population March 2011 1.5 Population Estimates Program GCT

- T1: Population Estimates U.S. Census Bureau http://www.census.gov/popest/eval

- estimates/eval

- est2010.html

Solvent Usage

- Surface Coatings Business Patterns 2011 2 County Business Patterns U.S. Census Bureau http://www.census.gov/econ/cbp/index.html
Unpaved Road Dust VMT 2011 2 Highway Statistics 2009 FHWA http://www.fhwa.dot.gov/policyinformation/statistics/2009/Emissions Inventory Guidance for Ozone [ & PM] NAAQS Implementation and Regional Haze Regulations 4/11/2014 DRAFT

B

- 1