July 27, 1994

William Kuykendal (MD-14)

Inventory Guidance and Evaluation Section

Emission Inventory Branch

Technical Support Division

Office of Air Quality Planning and Standards

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Subject: Final Report Entitled: "PM-10 Emission Inventory Requirements." 

(Contract No. 68-D2-0159, MRI Project No. I-13; 

Pechan Work Assignment No. 447.008)

Dear Bill:

Enclosed is one single-sided unbound master copy of the final report entitled: "PM-10 Emission

Inventory Requirements." As you requested, also enclosed is a WordPerfect 5.2 disk copy of the report,

and three double-sided bound copies. I also sent Mr. Roy Neulicht of MRI and Ms. Robin Dunkins of

EPA each a single-sided unbound copy and three double-sided bound copies. 

Please call me if you have any questions.

Sincerely,

Randy Strait

Senior Environmental Scientist

Enclosures

cc: Robin Dunkins, EPA

Roy Neulicht, MRI
PM-10 EMISSION INVENTORY REQUIREMENTS

Final Report

September 1994

Prepared for:

Emission Inventory Branch (MD-14)

Sulfur Dioxide/Particulate Matter Programs Branch (MD-15)

Office of Air Quality Planning & Standards

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Prepared by:

E.H. Pechan & Associates, Inc.

3500 Westgate Drive, Suite 103

Durham, NC 27707

Contract Nos. 68-D9-0168; 68-D2-0159

Work Assignment Nos. 28 and 2/35; 1/07 and 1/13

Pechan Report No. 94.07.002/447.008
ii

DISCLAIMER

The information in this document has been funded wholly by the United States

Environmental Protection Agency under Contract Number 68-D9-0168, Work Assignment

Numbers 28 and 2/35; and Contract NO. 68-D2-0159, Work Assignment Numbers 1/07 and 1/13,

to E. H. Pechan & Associates, Inc. Mention of trade names or commercial products does

not constitute endorsement or recommendation for use.
iii

CONTENTS

Page

LIST OF TABLES ............................. iv

ACRONYMS ................................ v

1.0 OVERVIEW OF DOCUMENT ....................... 1

1.1 Purpose ........................... 1

1.2 How to Use This Document .................. 1

2.0 DEFINITIONS AND REGULATORY REQUIREMENTS .............. 2

2.1 Definitions of PM-10 .................... 2

2.1.1 Primary PM-10 ..................... 2

2.1.2 Condensible PM-10 ................... 2

2.1.3 Secondary PM-10 (PM-10 Precursors) .......... 2

2.2 Summary of Regulatory Requirements ............. 3

2.2.1 Nonattainment Designations .............. 3

2.2.2 Classification .................... 3

2.2.3 Nonattainment Area Boundaries ............. 3

2.2.4 SIP Requirement Submittal Timelines .......... 4

2.2.5 Attainment Demonstration ............... 4

3.0 EMISSION INVENTORY ........................ 7

3.1 Summary of Inventory Types ................. 7

3.2 Temporal Resolution of Inventory .............. 9

3.3 Inventory Preparation Plan (IPP) .............. 9

3.3.1 IPP Point Source Requirements ............. 10

3.3.2 IPP Area and Mobile Source Requirements ........ 10

3.3.3 Other IPP Requirements ................ 11

3.4 Base Year Inventory ..................... 11

3.4.1 AIRS Compatible Reporting ............... 12

3.4.2 Geographic Coverage .................. 13

3.4.3 Applicable Source Categories ............. 13

3.4.3.1 Point Sources ............... 13

3.4.3.2 Area and Mobile Sources .......... 14

3.4.4 Rule Effectiveness .................. 15

3.5 Updating Inventories .................... 15

3.6 Adjustment of Base Year Inventory (Backcasting) ....... 15

3.7 RFP Projection Inventories ................. 16

3.8 Modeling Inventories .................... 16

3.8.1 For Multi-source Areas ................ 16

3.8.2 Background Sources .................. 18

4.0 DOCUMENTATION/DATA MANAGEMENT AND REPORTING OF THE INVENTORY ... 19

4.1 Documentation ........................ 19

4.2 Data Management and Reporting ................ 22
iv

5.0 REFERENCES ............................ 23

APPENDIX A INVENTORY PREPARATION PLAN (IPP) REVIEW CHECKLIST ...... 25
v

LIST OF TABLES

Number Page

2.1 Moderate Nonattainment Area Due Dates ............... 5

2.2 Serious Nonattainment Area Due Dates ................ 6

3.1 Basic Outline of an Inventory Preparation Plan ........... 12

3.2 Model Emission Input Data for Point Sources ............ 17

4.1 Outline for EPA Recommended Format/Contents for PM-10 Emission

Inventory Reports ......................... 20
vi

ACRONYMS

AFS AIRS Facility Subsystem

AIRS Aerometric Information Retrieval System

AMS AIRS Area and Mobile Source Subsystem

BACM Best Available Control Measure

BACT Best Available Control Technology

CAA Clean Air Act as amended in 1990

CHIEF Clearinghouse for Inventories and Emissions Factors

EPA U.S. Environmental Protection Agency

FIRE Factor Information Retrieval System

FTA fail to attain

FTD fail to demonstrate

Hr hour

IPP inventory preparation plan

MMBtu million British thermal units

NAAQS National Ambient Air Quality Standard

PM-10 particulate matter that measure less than or equal to

10 micrometers in aerodynamic mass median diameter

QA quality assurance

QC quality control

RACM Reasonably Available Control Measure

RACT Reasonably Available Control Technology

RE rule effectiveness

RFP reasonable further progress

SCRAM Support Center for Regulatory Air Models

SIP State implementation plan

TTN Technology Transfer Network

VMT vehicle miles traveled
1

SECTION 1.0

OVERVIEW OF DOCUMENT

1.1 Purpose

This document describes the emission inventory requirements that are

contained, either explicitly or implicitly, in the Clean Air Act as amended in

1990 (CAA) for those areas that are required to submit a State Implementation

Plan (SIP) for demonstrating attainment of the National Ambient Air Quality

Standard (NAAQS) for PM-10. The guidance in this document pertains to PM-10

moderate nonattainment areas and to areas that have been reclassified as

serious nonattainment areas. The purposes of the document are to (1) identify

the types of inventories required; (2) briefly review the regulatory

requirements pertaining to submission of these inventories; (3) describe the

objectives, components, and ultimate uses of the inventories; and (4) define

documentation and reporting requirements for the inventories.

1.2 How to Use This Document

This document is intended to be a guide for State and local agencies to

refer to for the requirements as prescribed by the CAA for submitting their

emission inventories; it is not a procedures document covering the methods for

compilation or reporting of emission inventories. The U.S. Environmental

Protection Agency (EPA) will issue further guidance pertaining to procedures

for preparing, compiling, and reporting emission inventories. It is

recommended that State and local agencies consult the references listed in the

Section 5.0 of this document for additional information.

This section provides an overview of the document organization and

contents. The key points and format of the material presented in the

remaining sections of this document are as follows.

Section 2.0 contains definitions and discussions of PM-10 categories and

presents a brief overview of the regulatory requirements and milestones for

PM-10 emission inventories under the CAA. State personnel should reference

the General Preamble for specific language on the regulatory requirements and

should consult the appropriate Regional Office of EPA to identify any guidance

issued subsequent to the General Preamble.

The specific details of inventory development and compilation

requirements are the focus of Section 3.0. In this section, requirements for

Inventory Preparation Plans (IPPs) are described. The major discussion in

this section focuses on the components of the base year inventory, while brief

discussion is also included regarding other types of inventories -- modeling, 

and periodic [i.e., reasonable further progress (RFP) and maintenance plan] 

inventories. Presentation of the base year inventory includes an overview of

the applicable source categories to be included -- point, area, and mobile

sources. In addition, requirements regarding the temporal resolution of the
2

inventory and adjustments to the base year inventory are also presented in

Section 3.0.

Section 4.0 discusses documentation/data management and reporting

requirements for SIP inventories prepared in response to the CAA. Section 5.0

provides the references for this document. Appendix A provides a checklist

for IPPs.
3

SECTION 2.0

DEFINITIONS AND REGULATORY REQUIREMENTS

This section of this document summarizes information in the General

Preamble dealing with the regulatory requirements for designations and

classifications, nonattainment area boundaries, and SIP submittal timelines. 

State personnel should reference the General Preamble for specific language on

the regulatory requirements and should consult the appropriate Regional Office

of EPA to identify any guidance issued subsequent to the General Preamble.

2.1 Definitions of PM-10

PM-10 is defined as particulate matter that measures less than or equal

to 10 micrometers in aerodynamic mass median diameter. PM-10 may be directly

emitted into the atmosphere from a source or it may be formed in the

atmosphere as a result of condensation or chemical reactions of other

pollutants.

2.1.1 Primary PM-10

Primary particulate matter is broadly defined as particles that enter

the atmosphere as a direct emission from a stack or an open source. It is not

formed due to a chemical reaction that occurs once the matter has been

emitted. The focus of emission inventories for PM-10 nonattainment areas

should be on primary PM-10 emissions. However, in some areas secondary and

condensible PM-10 account for a significant portion of PM-10 in the atmosphere

and, therefore, these would need to be included in the emission inventory.

2.1.2 Condensible PM-10

Condensible particulate matter (or condensed particulate matter, as it

is synonymously described) can be broadly defined as material that is not

particulate matter at stack conditions but which condenses and/or reacts (upon

cooling and dilution in the ambient air) to form particulate matter

immediately after discharge from the stack. Condensible particle matter forms

in a few seconds in the stack exhaust due primarily to immediate cooling and

air dilution. Condensible particulate matter is of potential importance

because it usually is quite fine and thus falls primarily within the PM-10

fraction. As a consequence, condensible particulate matter should always be

included in the emission inventory.

2.1.3 Secondary PM-10 (PM-10 Precursors)

Secondary particulate matter can be broadly defined as particles that

form through chemical reactions in the ambient air well after dilution and

condensation have occurred (i.e., usually at some distance downwind from the

emission point). An example of this phenomenon is the formation of sulfate

particles in a plume from the oxidation of sulfur dioxide by one of several
4

atmospheric transformation mechanisms. Generally, secondary particulate

matter can be distinguished from condensible particulate matter by the time

and/or distance downwind from the stack required for formation. Precursor

emissions contributing to secondary particulate matter should not be included

in the PM-10 inventory except where EPA and the State determines that the

sources of PM-10 precursors contribute significantly to PM-10 levels which

exceed the PM-10 NAAQS in the area. This determination will be based upon air

quality analysis in which States assess the contribution of precursors.

If precursors contribute significantly to nonattainment, States will

need to consider both the source-receptor relationship and the significance of

precursor contributions to overall nonattainment. In making a determination

regarding significance, EPA will rely in part on the technical information

contained in the State's submittal which could include filter analyses, an

assessment of the relative contribution of precursors to overall

nonattainment, and the State's Reasonable Available Control Technologies

(RACT)/Reasonably Available Control Measures (RACM) strategy. States are

encouraged to submit additional material for consideration, since all findings

will be made on a case-by-case basis.

2.2 Summary of Regulatory Requirements

State personnel should refer to the General Preamble for the

Implementation of Title I of the CAA of 1990 for specific language on the

regulatory requirements for moderate nonattainment areas according to the CAA. 

In general, the General Preamble addresses issues concerning condensible and

secondary PM-10. States should contact the Sulfur Dioxide/Particulate Matter

Programs Branch for case-by-case determinations.

States must develop and submit a SIP which will demonstrate attainment

of the PM-10 NAAQS for every area designated nonattainment and classified as

moderate for PM-10 under the CAA, within 18 months after being designated

nonattainment for PM-10. The Sulfur Dioxide/Particulate Matter Programs

Branch has prepared a staff work product as a supplement for the General

Preamble which addresses serious nonattainment area requirements (U.S. EPA

1993a).

2.2.1 Nonattainment Designations

On the date of enactment of the CAA Amendments of 1990, areas meeting

the qualifications of Section 107(d)(4)(B) of the Act were designated

nonattainment by operation of law; all other areas were designated

unclassifiable. Subsequent to the date of enactment, the EPA may redesignate

any of these unclassifiable areas as nonattainment under the provisions of

Section 107(d)(3).

2.2.2 Classification

Once an area is designated nonattainment, Section 188 of the CAA

outlines the process for classification of the area and establishes the area's

required attainment date. In accordance with Section 188(a), at the time of
 

1

RACM and BACM refer to control measures for both point and area sources

in moderate and serious PM-10 nonattainment areas, respectively. RACT

and best available control technologies (BACT) refer to control measures

for only point sources in moderate and serious PM-10 nonattainment areas,

respectively. See the General Preamble for further discussion of this

terminology.

5

designation all PM-10 nonattainment areas are classified as moderate by

operation of law.

A moderate nonattainment area can be reclassified as serious if the EPA

determines that:

1) the area cannot "practicably" attain the PM-10 NAAQS by the

applicable attainment date [i.e., fails to demonstrate (FTD)], or

2) the area has failed to attain (FTA) the PM-10 NAAQS by the

applicable attainment date [see Section 188(b)].

The EPA also has discretionary authority under Section 188(b)(1) to reclassify

any of these areas as serious at any time if the EPA determines they cannot

practicably attain the PM-10 NAAQS by the applicable attainment date.

2.2.3 Nonattainment Area Boundaries

The EPA must notify the Governor of each State of the requirements to

designate areas with respect to PM-10. For the areas that a Governor

designates nonattainment, the Governor will need to define the boundaries of

such areas. The boundaries for a nonattainment area should be consistent with

Section 107(d)(1)(A)(i) of the CAA, and the emission inventory must correspond

to the boundaries. A defensible rationale must be submitted to EPA to justify

an area's designation and boundaries. The boundaries designated by the

Governor of a State will be subject to final approval by EPA. 

2.2.4 SIP Requirement Submittal Timelines

Tables 2.1 and 2.2 present the schedule and due dates for SIPs for

moderate and serious areas, respectively. The moderate area SIPs containing a

New Source Review permit program revision, attainment demonstration, and RACM

are due 18 months after being designated nonattainment. For serious areas, a

SIP containing Best Available Control Measures (BACM) is due 18 months after

reclassification. Implementation of either RACM or BACM (dependent upon the

area's designation) is to be completed within 4 years after designation.1

2.2.5 Attainment Demonstration

Section 189(a)(1)(B) provides that States with moderate PM-10

nonattainment areas must submit a demonstration (including air quality

modeling) showing either attainment by the applicable attainment date or that

attainment by the applicable date is impracticable. The attainment
6

demonstration projects how the area will come into attainment (or will fail to

attain) with the NAAQS based on air quality modeling with forecasted

emissions. The SIP must contain the emissions forecasts used in the air

quality modeling attainment demonstration. In general, attainment

demonstrations for these areas will be reviewed in accordance with the general

guidance addressing PM-10 [PM-10 SIP Development Guideline, (U.S. EPA, 1987);

PM-10 Moderate Area SIP Guidance: Final Staff Work Product (U.S. EPA, 1991a);

and PM-10 Serious Area SIP Guidance: Final Staff Work Product (U.S. EPA,

1993a)] and any future applicable EPA guidance or regulations. For current

compilation of available policy and guidance for the PM-10 program, the reader

should refer to PM-10 Guideline Document and Appendix (U.S. EPA, 1993b).
7

Table 2.1 Moderate Nonattainment Area Due Dates

Event Months following

designation

Designation as nonattainment 0

Classification (moderate by operation of law) 0

Inventory Preparation Plan (IPP) 3

Draft Inventory 12

SIP due containing:

a) New Source Review permit program

b) attainment demonstration that includes

1) air quality modeling

2) base year actual emissions inventory

3) modeling inventory (projected

allowables at attainment [i.e., at 72

months])

4) inventory showing projected allowables

at 48 months when RACM/RACT is

implemented

c) RACM/RACT implementation program

d) Quantitative milestones (RFP)

e) PM-10 precursors assessment

18

Decision by EPA whether to reclassify area as serious for

FTD attainment (18 months from submission)

36

Implementation of control strategies, including RACM/RACT 48

RFP Milestone due date 54

Determination by EPA that State's RFP milestone is met 57

SIP revision due for failure to report RFP milestone or

determination by EPA that milestone was not met

63

Attainment (as expeditiously as possible but no later

than)

72

Redesignation to serious if in violation of NAAQS after

attainment date

72-78
8

Table 2.2 Serious Nonattainment Area Due Dates

Event Months following

reclassification

Reclassification 0

Inventory Preparation Plan (IPP) 3

Draft Inventory (The base year for FTA will be the actual

emissions for the year the area should have attained; for

FTD areas the base year inventory will become the

modeling emission inventory projected to the attainment

year)

12

RFP Milestone due date *

Determination by EPA that State's RFP demonstration is

adequate

**

BACM SIP due containing:

a) BACM/BACT implementation program (schedule

for implementation)

b) PM-10 precursors assessment

c) base year inventory

18

SIP revision due for failure to report RFP milestone or

determination by EPA that milestone was not met

***

Full SIP containing BACM SIP information and:

a) attainment demonstration with air quality

modeling

b) additional BACM/BACT requirements

48

Implementation of BACM/BACT 48

RFP Milestone is due †

Determination by EPA that State's RFP milestone is met ††

SIP revision due for failure to report RFP milestone or

determination by EPA that milestone was not met

†††

RFP Milestone is due †

Determination by EPA that State's RFP milestone is met ††

SIP revision due for failure to report RFP milestone or

determination by EPA that milestone was not met

†††

Attainment (as expeditiously as possible but no later

than)

120

* 54 months after designation as a moderate nonattainment area for areas

that FTD; 90 months after designation as a moderate nonattainment area

for areas that FTA

** 3 months following *
9

*** 6 months following **

† 3 years following previous RFP milestone due date

†† 3 months following †

††† 6 months following ††
10

SECTION 3.0

EMISSION INVENTORY

3.1 Summary of Inventory Types

For PM-10 nonattainment areas, there are three (3) basic kinds of

inventories that States may need to develop under the CAA. These include base

year inventories, periodic inventories, and modeling inventories. The

information presented below represents EPA's view of accurate, complete, and

approvable inventory submittals.

The base year inventory is the primary inventory from which all other

inventories are derived. All inventories shall be consistent with data

provided in the base year inventory. Section 172(c)(3) of the CAA requires

States to ensure that this inventory is comprehensive, accurate, and current

for all actual emissions of PM-10. The base year inventory must include

emissions from all point, area, and mobile sources.

For moderate nonattainment areas, the SIP base year emission inventory

must be based on actual emissions. For moderate and serious nonattainment

areas, the base year for emission inventories must be consistent with the

3 years of data which were necessary to designate the area as nonattainment. 

The base year inventory is the inventory of actual emissions for the chosen

base year. The base year inventory should reflect the last year of the

3 years used to determine nonattainment.

Should a moderate nonattainment area "fail to demonstrate" (FTD)

attainment, then the area will be reclassified as serious. This will require

submission of a serious area base year emission inventory which is due

18 months following reclassification (see Table 2.2). The serious area base

year emission inventory also serves as the BACM SIP emission inventory. 

Moderate areas that FTD attainment and have been reclassified can use the

moderate area attainment demonstration emission inventory (see modeling

inventories below) as a starting point for their serious area base year/BACM

emission inventory, but it must include any changes (such as shutdowns or

emission factor changes) that have occurred since the moderate area SIP was

submitted. This means that the year that would have been the attainment year

under the moderate area provisions becomes the base year for the serious area

SIP inventory. It also assumes that the moderate area SIP regulations (i.e.,

RACM) will be implemented, however, should the area be redesignated as

serious, BACM requirements will need to be implemented. BACM implementation

may require additional control measures or technologies on processes already

controlled under the RACM implementation. All of the above information

pertaining to serious areas assumes that the moderate area SIP emission

inventory was adequate and that if it was not, it was returned to the State as

part of the completeness and SIP review process that is part of the moderate

area requirements.
11

Should an area classified as serious "fail to attain" (FTA), then those

areas must reinventory the actual emissions at the time they should have

attained. Such an inventory would be due 18 months after determining that the

area FTA.

Modeling inventories may be used as a tool for a number of purposes

including model performance evaluations, projection to future years,

evaluation of the impact of rulemaking, evaluation of control measures and

technology, receptor modeling reconciliation, and determination of design

concentrations. One of the major roles for modeling inventories will be for

use in the attainment demonstration. Modeling inventories can be based upon

either allowable or actual emissions, depending on the purpose of the

modeling. For instance, modeling inventories should be based on the actual

daily emissions for model performance evaluation. For control measure

evaluations and the attainment demonstration, the modeling emission inventory

consists of allowable emissions for the base year and projected allowables for

the attainment year. Modeling inventories also have additional data

requirements (e.g., stack parameters). The Guideline on Air Quality Models

(Revised) should be consulted to determine the additional data needed (U.S.

EPA, 1986).

For moderate areas, an attainment demonstration emission inventory that

provides a projection of allowable emissions to the year following full

implementation of the moderate area SIP is required. The year of record for

this inventory would be the seventh year following designation as a moderate

nonattainment area.

For serious areas, the attainment demonstration emission inventory

provides a projection of allowable emissions for the year following

implementation of the serious area SIP. This inventory is due with the

serious area attainment demonstration SIP (see Table 2.2).

The CAA states that the emission inventories may be periodically updated

as deemed necessary by the Administrator. A periodic inventory may be the

consequence of RFP requirements, a maintenance plan for an attainment area, or

for other reasons deemed necessary by EPA. The PM-10 program will not

arbitrarily require inventories every 3 years. It will rely on "event"

oriented periodic emission inventories and, therefore, will be decided on a 

case-by-case basis. Guidance from EPA for States related to requirements and

events that will trigger development of a PM-10 emission inventory is

forthcoming. Questions related to this topic should be addressed to the

Office of Air Quality Planning and Standards, Air Quality Management Division,

Sulfur Dioxide/Particulate Matter Programs Branch.

As a result of the RFP requirement, a detailed compliance schedule or

inventory (RFP projection inventory) may be required. If an RFP projection

inventory were to be used by the States for demonstrating that the emission

reductions will be achieved, the following applies.

For moderate nonattainment areas, the RFP projection inventory

(i.e., RFP milestone) will be due 3 years after the SIP inventory
12

submittal (see Table 2.1). The RFP projection inventory is to be based

on allowable emissions. It should be based on the base year inventory,

but should incorporate any significant changes including rule

effectiveness (RE) and RACM implementation.

It should be noted that only one RFP milestone will be required

for moderate nonattainment areas assuming that they are in attainment on

their required attainment date. The reason for this can be ascertained

by referring to Table 2.1. The RFP milestone is due 54 months following

designation as a moderate nonattainment area. The next RFP

demonstration would be due 3 years later (i.e., 90 months following

designation), however, attainment is scheduled for 72 months. Should

the moderate area fail to reach attainment at the scheduled time and be

reclassified as a serious nonattainment area, then the RFP schedule

continues from the original moderate area schedule. Thus, an RFP

projection inventory for a serious nonattainment area could be required

at the same time as the BACM SIP inventory is due if the area is

reclassified as serious 72 months after being designated as a moderate

nonattainment area.

Another circumstance which would trigger a periodic inventory would be

when an area becomes eligible for redesignation. Maintenance plan emission

inventories are required once an area has reached attainment and desires to be

redesignated to and continue as an attainment area. An unclassified area

requesting redesignation to attainment must also submit a maintenance plan

emission inventory.

The maintenance plan emission inventory should include an

attainment inventory as well as a maintenance inventory. The attainment

inventory should include actual emissions at the time of attainment or

at the time of the request for redesignation as attainment. The

maintenance inventory should present projections of allowable emissions

for the ninth year following reclassification to attainment. Another

periodic inventory may be required within the 9-year time frame for

failure to maintain or for a SIP call. States should refer to the

redesignation policy for additional requirements for redesignations.

3.2 Temporal Resolution of Inventory

States will have to model short-term (daily) and long-term (annual) air

quality for PM-10 to assure that both standards will be protected, even if air

quality measurements show exceedances for only one time period. 

Some areas may experience seasonal emissions increases which largely

cause their nonattainment problem. If the problem involves only one season

(e.g., summer wind blown dust), then a seasonal inventory should be prepared

in addition to an annual inventory. In dual season situations (e.g., summer

wind blown dust and winter wood burning), an emission inventory should be done

for each season separately, and the results combined for the analysis of the

annual standard. The reporting convention for seasonal emissions must be

consistent for point, area, mobile, and natural sources.
13

3.3 Inventory Preparation Plan (IPP)

For base year inventories, the EPA requires States to prepare a brief

IPP that specifies how they intend to develop, document, and submit their

inventories. The plans provide States the opportunity to notify the EPA how

they plan to compile the required inventories and to allow the EPA to provide

important feedback to prevent the use of approaches that are not consistent

with the EPA requirements. With the use of IPPs, the EPA can help guide the

preparation of required inventories and ensure that emission estimates are of

high quality and are consistent with the PM-10 emission inventory

requirements. States shall submit IPPs to the EPA Regional Offices and the

EPA headquarters according to the schedule shown in Table 2.1.

In addition to technical data, the IPPs should contain a schedule

showing when the State plans to submit the draft and final inventory to the

EPA. If the State plans to submit an inventory in component pieces (e.g.,

point source component, area source component, etc.), the IPP must clearly

make this distinction and indicate a draft and final submittal date for each

component. The final submittal dates shall be consistent with the PM-10

emission inventory requirements. A complete draft inventory is required to be

submitted to the EPA Regional Offices and the EPA headquarters within

12 months after the date that an area is designated nonattainment. The IPP

shall also explicitly detail the year chosen as the base year for the

inventory, and explain the basis for the selection. Further details on the

base year inventory are found in Section 3.4.

In addition to the IPP submittal to the EPA Regional Office, the State

shall also submit a copy of the IPP and any correspondence relating to the IPP

to the EPA headquarters. The copy should be addressed to: Chief, Inventory

Guidance and Evaluation Section, Emission Inventory Branch (MD-14), Technical

Support Division, U.S. EPA, Research Triangle Park, NC 27711.

States must prepare an IPP for each nonattainment area for which a base

year inventory is required by the CAA, to the extent that different approaches

will be used. If a State has multiple nonattainment areas but plans to use

the same overall approach for each, the State may submit a single IPP that

details that approach and the areas to which it will apply. In detailing the

approach utilized for developing the inventory for the area(s), the IPP must

clearly delineate that the IPP was prepared for the purposes of a PM-10 SIP,

must define the nonattainment area(s) addressed by the inventory and the

nonattainment classification of the areas. In addition, the IPP should

identify the persons responsible for the inventory, the contents and

organization of the report, submission schedules, any modifications to the

approach used for multiple area submittals, the source categories inventoried,

and a summary of the emissions documentation information for each major

inventory component (i.e., point, area, and mobile sources).

States must be aware that the EPA considers submittal of an IPP crucial

to an approvable SIP inventory. By approving an IPP, the EPA will accept the

intended approach for inventory compilation. The EPA's approval of an IPP

does not, however, signify that the EPA unconditionally accepts all of the

information to be contained in the actual inventory. That inventory will be
14

reviewed separately and on its own merits regardless of how well the IPP was

assembled.

3.3.1 IPP Point Source Requirements

For point sources, States shall define how all pertinent emission

sources will be identified and located. States shall describe how point

source activity levels and associated parameters will be developed, and how

these data will be used to calculate emission estimates. States shall also

discuss how and when statewide point source reporting to the EPA will be

conducted and how it will be coordinated with reporting for area and mobile

sources. States must indicate whether or not RE was applied and, if it was,

the basis for determining control efficiencies. States must describe any

source surveys that are planned, and if they intend to use existing data

contained in the Aerometric Information Retrieval System (AIRS)/Facility

Subsystem (AFS), individual State emissions systems, or State permitting

files. 

3.3.2 IPP Area and Mobile Source Requirements

For area sources and mobile sources, the IPP shall explicitly state

which source categories will be addressed and which will not be addressed

(with justification for exclusion). For those categories to be included, the

plan shall indicate what calculational method will be used to estimate

emissions. If a State plans on using the EPA's inventory guidance for all

categories, it shall report that it will be applying the EPA's guidance and

the reference(s) for the guidance. If the EPA guidance has alternative

methods for a category, the IPP shall clearly indicate which method the State

intends to use in its inventory. Particular emphasis shall be given to

categories for which the State plans to use an approach other than that

recommended in the EPA's guidance. Any major assumptions that may affect the

development of emission estimates in a category shall be clearly stated. The

IPP must also identify the sources of activity data, whether RE will be

applied (and how it was determined if applied), and the basis for determining

control efficiencies.

For on-road mobile sources, the IPP shall include a discussion of how

the State intends to develop vehicle miles traveled (VMT) estimates, and how

PM-10 emission factors for mobile sources will be determined. The Office of

Mobile Sources has developed a mobile source particulate model (PART5). The

Part5 model and user's manual may be obtained from EPA's Bulletin Board System

for the Office of Mobile Sources on the TTN. The PART5 model provides

emission factors for mobile sources travelling on paved and unpaved roads. If

the PART5 emissions model was not utilized or was not available prior to the

inventory submittal deadline, the basis for the alternative estimation

methods, any key modeling assumptions, and the vehicle classes covered must be

discussed in the IPP. 

The PART5 model does not address emissions for nonroad mobile sources

(e.g., construction, farm, industrial, and lawn and garden equipment;

motorcycles; and snowmobiles). Methodologies for estimating emissions from
15

these sources are documented in Nonroad Engine and Vehicle Emission Study --

Report (U.S. EPA, 1991b).

3.3.3 Other IPP Requirements

The IPP must indicate the modeling choice for the attainment

demonstration, the modeling inventories developed for modeling, a definition

of the modeling area, when the modeling inventory data will be submitted, and

a discussion of coordination planning between inventory and modeling

personnel.

The IPP must also clearly describe how the State plans to present,

document, and submit the inventory to the EPA. The types of documentation

that will be provided and the form of this documentation must be described to

the extent that the EPA can judge if it would be satisfactory for inventory

review purposes. The IPP shall specify the written and computerized methods

that the State plans to use to compile and submit its data. The State must

contact its EPA Regional Office to determine computerized data submittal and

format requirements, and must describe in its IPP how its data system (e.g.,

AIRS, State system) will be used to submit the data to EPA.

States are required to submit Quality Assurance (QA) plans as an initial

step in their inventory development work and receive EPA approval on their

plans early on in the process. The QA plans must be submitted as part of a

State's IPP. The content and general form of QA plans must be consistent with

previously issued guidance (U.S. EPA, 1988b). This plan shall describe the

overall QA program that the State intends to use during the compilation of the

inventory.

IPPs should be concise, and only provide as much detail as is necessary

to communicate to the agency how the State intends to develop and present its

inventory. However, the document must contain sufficient information to

enable the EPA to make a judgement that the State's intended inventory

approach is sound and consistent with the EPA's guidance and requirements. 

Although no specific IPP format is required, the discussion should include the

topics listed in Table 3.1. In addition, the checklist that the EPA plans to

use to guide the review of the IPPs is included in Appendix A.

3.4 Base Year Inventory

[Note: This section discusses information contained in part in the

Guideline on Air Quality Models (Revised) (U.S. EPA, 1986). In the future, if

information in the Guideline on Air Quality Models or official interpretation

of the Guideline on Air Quality Models are not consistent with the discussion

in this section, the Guideline on Air Quality Models interpretation shall be

used.]

Section 172(c)(3) of the CAA requires that the base year inventory be a

comprehensive, accurate, and current inventory of actual emissions in the

nonattainment area. The inventory shall include PM-10 emissions from all

point, area, and mobile sources. 
16
17

Table 3.1 Basic Outline of an Inventory Preparation Plan

A. Introduction

! Define the boundaries of the nonattainment area.

! Describe the basis for the inventory (i.e., previous efforts that

are viable and related); indicate the starting point.

! Define how the plan is structured and what it contains.

! Specify who is responsible for the inventory and who is actually

compiling it (air agency, consultants, etc.).

B. Point Source Approach

! How will sources be identified and located?

! What categories will be addressed and why?

! What categories will be excluded and why?

! Define the use of existing data sources.

! Identify data collection methods to be used.

! Provide the basis for activity level data and emission estimates.

! Provide the basis for control efficiencies.

! Discuss the application of RE.

! Indicate the basis for RE levels.

C. Area and Mobile Sources Approach

! What categories will be addressed and why?

! What categories will be excluded and why?

! What estimation methods will be used (e.g. AP-42, Emission

Inventory Procedures Document, site specific surveys, etc.)?

! What methods will be used for collecting activity/commodity level

data?

! Provide specification of the mobile source emissions model used.1

! Discuss application of RE.

! Provide basis for RE levels.

D. Documentation Approach

! Describe written presentation and documentation.

! Describe computerized compilations and documentation.

! Describe the data required to be submitted to EPA (as defined by

the EPA Regional Office) and the computerized format that will be

used to submit the data.

E. QA Plan

! Describe the QA program.

! How will the QA program affect and benefit the inventory.

! Verify adherence to previously issued QA guidance (U.S. EPA,

1988b).

1 PM-10 emissions factors for mobile sources should be obtained by

running the PART5 model.
18

3.4.1 AIRS Compatible Reporting

The official repository for all emission inventory data will be

designated by the EPA Regional Office. One of the options that may be

designated by the Regional Offices is to have the official data record in

AIRS. If this option is selected, all SIP data must be loaded directly into

AIRS or submitted in an AIRS compatible format. 

Emission Inventory Branch (inventory requirements) and National Air Data

Branch (data system enhancements, schedules, and availability) can provide

coordination with State and local agencies during the inventory preparation

process for both batch transactions to the AIRS Repository and on-line

interactive submittal of AFS and Area and Mobile Source Subsystem (AMS) SIP

inventory data. As the PM-10 program defines data-system needs (now and in

the future) the system will be enhanced to meet these needs. Therefore, it

would be appropriate for State and local agencies to coordinate with EPA

regarding availability of new and scheduled enhancements to AIRS during the

preparation of IPPs and prior to actual inventory data entry.

3.4.2 Geographic Coverage

The geographic boundaries of the inventory area shall be determined by

the area officially designated nonattainment. At a minimum, this area shall

be included in the emission inventory. However, the attainment demonstration

developed as part of the SIP inventory process must include air quality

modeling. As a consequence, sources contributing significant fractions to the

ambient concentrations must also be included. This may necessitate the

inclusion of sources outside the boundary of the nonattainment area in the

emission inventory. The nonattainment area coupled with any other areas

containing sources that need to be included in the attainment demonstration

modeling effort are considered the modeling domain. Guidance on the

geographic coverage and other modeling criteria can be found in the Guideline

on Air Quality Models (Revised) (U.S EPA, 1986). Current code for EPA

approved air quality models are available through the EPA's Office of Air

Quality Planning and Standards SCRAM (Support Center for Regulatory Air

Models) Bulletin Board System and the related programs can be downloaded to a

personal computer diskette. Information is also included with regard to

upgrades to various models.

The extent of the sources to be included in the emission inventory

outside the immediate nonattainment area must be determined by the State. The

decision is based on the types of sources in upwind areas and on their

potential impact inside the nonattainment area. However, documentation of

rationale used in determining which sources to include or exclude must be

provided as part of the emission inventory submittal. In addition, a brief

discussion of this rationale should be included in the IPP. Coordination 

between the State inventory preparation staff and the air quality modeling

staff will facilitate efficient inventory preparation and submittal.
19

3.4.3 Applicable Source Categories

Base year emission inventories are required to include all types of

stationary point, area, and mobile sources. The particulate matter emission

factors in AP-42 can be used to assess if source categories should be included

in the inventory. For point sources, a list of source classification codes

and corresponding emission factors can be obtained from the program, FIRE

(Factor Information Retrieval System), by accessing the CHIEF (Clearinghouse

for Inventories and Emission Factors) Bulletin Board System on the Technology

Transfer Network (TTN). A list of area source category codes can be obtained

from the AMS training manual by accessing the AIRS Bulletin Board System on

the TTN.

3.4.3.1 Point Sources

Point sources are physical emission points or processes usually within a

plant that result in pollutant emissions. PM-10 point sources generally refer

to specific facilities or stacks for which individual records are collected

and maintained.

The nonattainment area classification affects the facility emissions

size required to be included in the base year inventory. For moderate areas,

all stationary sources which emit directly, or have the potential to emit

(i.e., allowable emissions), 100 tons per year or more of PM-10 must be

included in the inventory. These sources are referred to as "major stationary

sources" in Section 302(j) of the CAA.

For serious areas, all stationary sources or groups of stationary

sources located within a contiguous area and under common control that emit or

have the potential to emit at least 70 tons per year of PM-10 must be

included. (Section 189(b)(3))

The EPA also believes that the States' inventory may need to go beyond

those sources having a tons per year limit to include other sources in the

area that are reasonable to control.

3.4.3.2 Area and Mobile Sources

Area sources are generally defined as an aggregation of all sources not

defined as point sources in a specific geographic area. Area sources include

fugitive dust sources; mobile sources; and stationary sources that are too

small, difficult, or numerous to account for individually as point sources. 

Area sources also include residential wood combustion sources, and prescribed,

silvicultural and agricultural burning sources. 

The EPA issued technical information guidance documents on BACMs for

fugitive dust; residential wood combustion; and prescribed, silvicultural and

agricultural burning sources (U.S. EPA, 1988, 1989a, and 1992, respectively). 

Fugitive dust is particulate matter suspended in the air either by mechanical

disturbance of the surface material or by wind action blowing across the

surface. Mechanical disturbance includes resuspension of particles from

vehicles traveling over roadways, parking lots, and other open areas. Wind
20

action includes dust blown off disturbed open areas. Process fugitive

emissions should be included in the point source inventory. Residential wood

combustion includes wood smoke from residential wood stoves and fireplaces. 

Residential wood combustion is a significant source of PM-10 particularly in

nonattainment areas in the western United States. Prescribed burning

generally describes burning on lands that are being managed. This includes

both planned ignition and prescribed natural fire, however, it does not

include forest and wildfires. If a State excludes any of the emission sources

addressed in the three documents from its emission inventory, it must provide

documentation on why the source(s) were excluded.

The EPA has developed the Part5 model for estimating PM-10 emissions

from mobile sources. The model can be used to estimate total particulate

matter emissions as well as particulate matter fractions ranging from 1.0 to

10 micrometers. For gasoline engines, total exhaust particulate matter

includes direct sulfate (exhausted as sulfuric acid) and lead emissions. For

diesel engines, total exhaust particulate matter also includes emissions for

soluble organic fraction and the remaining carbon portion. Each of these

emission components can also be estimated individually. The Part5 model can

also be used to estimate the following:

! Particulate matter from brake and tire wear,

! Gaseous sulfur dioxide exhaust emissions,

! Indirect sulfate emissions formed later in the atmosphere

associated with sulfur dioxide exhaust emissions, 

! Fugitive dust emissions from paved and unpaved roads, and

! Idle-speed exhaust emissions.

The Part5 model and user's manual may be obtained from EPA's Bulletin

Board System for the Office of Mobile Sources on the TTN.

3.4.4 Rule Effectiveness 

Rule effectiveness, currently not required, may be required by EPA at a

later date. The feasibility of and guidance on using RE are being studied by

EPA at this time. Until guidance is issued by EPA, RE may be considered by

the State at its option. Should the State exercise this option, RE should be

applied to all sources that are affected by a regulation and for which

emissions are determined by means of emission factors and control efficiency

estimates. No RE factor is needed in cases where no control is applied or

there is no applicable regulation.

Past inventories have assumed that regulatory programs would be

implemented with full effectiveness, achieving all of the required or intended

emission reductions and maintaining that level over time. However, experience

has shown regulatory programs to be less than 100 percent effective for most

source categories in most areas of the country. The concept of applying RE in

a SIP emission inventory has evolved from this observation. In short, RE
21

reflects the actual ability of a regulatory program to reduce emissions from

all sources at all times that are subject to a specific regulation.

Several factors should be taken into account when estimating the

effectiveness of a regulatory program. These include: (1) the nature of the

regulation (e.g., whether any ambiguities or deficiencies exist, whether test

methods and/or recordkeeping requirements are prescribed); (2) the nature of

the compliance procedures (e.g., taking into account the long-term performance

capabilities of the control); (3) the performance of the source in maintaining

compliance over time (e.g., training programs, maintenance schedule,

recordkeeping practices); and (4) the performance of the implementing agency

in assuring compliance (e.g., training programs, inspection schedules, followup procedures).

For base year PM-10 inventories under the CAA, the EPA will allow the

use of reasonable default values provided the values are justified by the

State. Justification may include a RE study performed according to the March

24, 1988 National Protocol. The RE factor shall be applied along with the

estimated control efficiency in the calculation of emissions from a source. 

An example of the application is as follows:

Uncontrolled emissions = 50 lbs/day

Estimated control efficiency = 90%

RE = 75%

Emissions after control = 50 [1 - (0.90)(0.75)]

= 50 [1 - (0.68]

= 16.25 lbs/day

Thus, the application of RE results in a total emission reduction of

68 percent.

3.5 Updating Inventories

Updating of prior year inventories to the base year inventory will, in

general, not be acceptable. A new inventory for the appropriate base year

should be prepared. A State that believes that a special situation exists in

which EPA should allow an existing inventory to be updated should apply to the

appropriate Regional Office for a written exception.

3.6 Adjustment of Base Year Inventory (Backcasting)

The EPA recognizes that adjustment of the base year inventory, or

backcasting, may be necessary. Backcasting is the recalculation of a previous

inventory due to changes in the parameters used to calculate the emissions

initially. Situations where backcasting may be invoked include changes in

emission factors, changes in calculational methods, or insufficient data for

the base year that may be more complete in a previous year. States may make

adjustments to base year inventories only with the approval of the EPA.
22

3.7 RFP Projection Inventories

The RFP inventory should "track" all sources that are subject to

regulations for the nonattainment area, whether or not they are actually in

the area. The inventory must be able to answer the question: "Is the State

achieving the agreed emission reductions specified in the SIP at any

particular time?" The basis for the reductions required will be the

attainment demonstration. Since there are no specific level of reductions

required under the CAA for PM-10 as there are for volatile organic compounds,

the level of reductions required will be determined by the RACM requirements

and what is necessary to demonstrate attainment of the PM-10 NAAQS by the

appropriate attainment date.

RFP projection inventories are to be projections of allowable emissions. 

In addition, the RFP projection inventory should include the effects of

control strategy implementation (such as RACM or BACM). Emission reductions

determined from the RFP projection inventories are to be based upon the base

year inventory which uses actual emissions. It is important to remember that

attainment will be based upon a target level of emissions (i.e., an amount of

emissions required to meet attainment) and that backcasting may necessitate an

adjustment of the target level of emissions. Some air planning agencies may

be used to thinking in terms of the emissions reduction required relative to a

current control strategy projection, rather than a target level of emissions.

Projections of attainment year emissions would be used to calculate the

required emissions reductions expressed on such a basis, by simply taking the

difference between the attainment year projection inventory (without controls

applied) and the attainment year target level of emissions. However, States

that choose this approach should be aware that the attainment year target

level is dependent only on the base year inventory, whereas the calculation of

an emission reduction required relative to the current control strategy

projection depends on the accuracy of the attainment year projection, which in

turn depends on the estimate of future growth in activities. The assessment

of whether an area has met the emission reduction requirement will be based on

whether the area is at or below the target level of emissions and not whether

the area has achieved a certain actual emission reduction relative to having

maintained the current control strategy.

3.8 Modeling Inventories

Modeling inventories may require inclusion of additional sources outside

the nonattainment area, as defined by the modeling domain. For this reason,

the modeling domain should be defined as early as possible so that emission

data for point, area, mobile, and natural sources can be gathered for the

entire modeling domain as part of the base year inventory preparation process. 

3.8.1 For Multi-source Areas

According to the Guideline on Air Quality Models (Revised) (U.S. EPA,

1986), all sources expected to contribute significantly to the ambient

concentrations in the nonattainment area or near the critical receptor for 
23

Table 3.2 Model Emission Input Data for Point Sources *

Emission Limit

(#/MMBtu)** X

Operating Level

(MMBtu/Hr)** X

Operating Factor

(e.g. Hr/Yr, Hr/day)

For Stationary Point Source(s) Subject to SIP Emission Limit(s) Evaluation for Compliance with

Ambient Standards (Including Areawide Demonstrations)

Averaging time

Annual & quarterly

Maximum allowable

emission limit or

federally enforceable

permit limit.

Actual or design

capacity (whichever is

greater), or federally

enforceable permit

condition.

Actual operating

factor averaged over

most recent

2 years.***

Short-term Maximum allowable

emission limit or

federally enforceable

permit limit.

Actual or design

capacity (whichever is

greater), or federally

enforceable permit

condition. 

Continuous operation,

i.e., all hours of

each time period under

consideration (for all

hours of the

meteorological data

base).** ***

For Nearby Background

Source(s)

Same input requirements as for stationary point source(s) above.

For Other Background

Source(s)

If modeled (see Section 9.2.3), input data requirements are defined

below.

Averaging time Annual &

quarterly

Maximum allowable

emission limit or

federally enforceable

permit limit.

Annual level when

actually operating,

averaged over the most

recent 2 years.***

Actual operating

factor averaged over

most recent 2

years.***

Short-term Maximum allowable

emission limit or

federally enforceable

permit limit.

Annual level when

actually operating,

averaged over the most

recent 2 years.***

Continuous operation,

i.e., all hours of

each time period under

consideration (for all

hours of the

meteorological data

base).*****

* The model input data requirements shown on this table apply to stationary source control

strategies for STATE IMPLEMENTATION PLANS. For purposes of emissions trading, new source

review, or prevention of significant deterioration, other model input criteria may apply. 

Refer to the policy and guidance for these programs to establish the input data.

** Terminology applicable to fuel burning sources; analogous terminology, e.g., #/throughput may

be used for other types of sources.

*** Unless it is determined that this period is not representative.

  Operating levels such as 50 percent and 75 percent of capacity should also be modeled to

determine the load causing the highest concentration.

** *** If operation does not occur for all hours of the time period of consideration (e.g., 3 or 24

hours) and the source operation is constrained by a federally enforceable permit condition,

an appropriate adjustment to the modeled emission rate may be made (e.g., if operation is

only 8:00 a.m. to 4:00 p.m. each day, only these hours will be modeled with emissions from

the source. Modeled emissions should not be averaged across nonoperating time periods).
24

emission limit(s) should be explicitly modeled. For evaluation for compliance

with the short term and annual ambient standards, the nearby sources should be

modeled using the emission input data shown in Table 3.2. The number of such

sources is expected to be small except in unusual situations. The nearby

source inventory should be determined in consultation with the reviewing

authority. It is envisioned that the nearby sources and the sources under

consideration will be evaluated together using an appropriate model [typically

selected from Appendix A of the Guideline on Air Quality Models (Revised)

(U.S. EPA, 1986)].

The impact of the nearby sources should be examined at locations where

interactions from several sources (plus natural background) can occur. 

Significant locations include: (1) the critical receptor(s) identified as

exceeding the NAAQS; (2) areas having a large number of significant sources in

a small area; (3) areas close to major sources; and (4) areas with peculiar

topography and/or meteorology that may result in enhanced impacts from several

sources. These locations may be identified through trial and error analyses

or by using screening model approaches.

3.8.2 Background Sources

Other sources not expected to contribute significantly to the ambient

concentration may include minor sources and distant major sources. That

portion of the background attributable to these sources should be determined

by application of a model using Table 3.2 or by the following procedure.

If there are no ambient PM-10 monitoring stations in the vicinity

of the source, a "regional site" may be used to determine the

background. A "regional site" is one that is not influenced by major

sources.

Alternatively, air quality data collected in the vicinity of the

source can be used to determine the background concentration. The

average annual background concentration can be calculated by excluding

those values when the source impacts the monitoring site.

Line sources commonly included in emission inventories are

roadways and streets along which there are well-defined movements of

motor vehicles, but they may be lines of stacks such as in aluminum

refineries. Area and volume sources are often collections of a

multitude of minor sources with individually small emissions that are

impractical to consider as separate point or line sources. Large area

sources are typically treated as a grid network of square areas, with

pollutant emissions distributed uniformly within each grid square.

After determining emissions for background sources, they may be entered

into the data system. For example, if AIRS is the data system and the source

is large enough to be tracked as a facility, data for the source could be

entered in AFS. To enter data in AMS, the activity or emission values must be

summed, or partitioned, to fit the geographic units used. For example,

highway data are not entered in AMS as "line sources." Highway data for the
25

appropriate vehicle-type and road-type categories are entered for the County

(if the County as a whole is the geographic unit being tracked). 
26

SECTION 4.0

DOCUMENTATION/DATA MANAGEMENT AND REPORTING OF THE

INVENTORY

4.1 Documentation

Base year emission inventory information under the CAA shall be provided

to EPA in written format. The written presentation must contain documentation

sufficient for the Agency to reproduce the emission estimates that are

submitted in the inventory. Written documentation requirements are summarized

in this section. 

Under the CAA, EPA is requiring that States prepare written inventory

documentation reports according to a more standardized set of guidelines. 

Although the organization of the inventory report is somewhat flexible,

Table 4.1 presents EPA's recommended outline for this report. Inventory

reports that are not prepared according to the outline will be harder for EPA

to review and are more likely to be deemed unacceptable by the Agency. The

EPA's primary interest is that all inventories address the crucial elements

inherent in a good inventory and provide summary data and documentation that

allow the quality of the inventory effort to be effectively judged. 

Inventories not meeting the minimum data reporting and documentation standards

established in this discussion shall be deemed unacceptable and returned to

the States for modification before any further technical quality review will

be performed.

The introduction to an inventory report shall contain a description of

the nonattainment area that has been inventoried, a listing of the

counties/areas covered, a map of the area, an identification of who prepared

the inventory and the respective contacts for major inventory components, a

description of major inventory problems or deficiencies, and a discussion of

how the remainder of the report is organized. After the introduction, the

report must contain a thorough summary of the emissions data by source type

(point, area, mobile, and natural) and geographic area. At a minimum, the

report must include summary emissions tables by source type, summary emissions

tables by county/area, and graphics illustrating the contribution to areawide

emissions by source type. If PM-10 precursor emissions are reported, they

should be presented in separate tables from primary and condensible PM-10

emissions. States are required to report emissions data on an annual basis.

Separate discussions must be presented to describe inventory development

procedures and results for point, area, mobile, and natural sources. In

addition to the specific parameters germane to these source types, each source

type discussion needs to explain how emissions were temporally allocated to a

daily basis and how RE was incorporated into each emission estimate.

The point source discussion shall include a description of how the list

of sources to be inventoried was identified. The report must also state if
27

any source categories were not considered in the inventory and why. The

discussion shall address the issue of completeness of source coverage. Data

collection methods and tools shall be thoroughly explained and documented. 

All information surveys that may have been conducted must be discussed and the

results provided (probably in an appendix). All sources inventoried shall be

listed according to their source category type (e.g., refinery, plant, etc.). 

The methodology by which activity levels and emissions were determined for

each plant or source category (when applicable) shall be succinctly but

explicitly explained. Large volumes of detailed data shall be put into

appendices but clearly linked to the text discussion in terms of how they were 
28

Table 4.1 Outline for EPA Recommended Format/Contents for PM-10 Emission Inventory

Reports

I. Cover and Title Page

A. Title (geographic area, type of inventories, pollutants, base year)

B. Responsible agency [e.g., NC Dept of Health and Natural Resource]

C. Report date (completed/distributed)

D. Preparer (if different from responsible agency - e.g., contractor)

II. Table of Contents

A. Contents

B. Tables

C. Figures

III. Introduction

A. Reason for report being prepared, purpose

[For example, In response to letter from _____ to _____, dated _____ requesting

preparation of a SIP for demonstration of attainment of PM-10 NAAQS in

(geographic area), beginning with an emission inventory for the base year. 

Base year emission inventory serves as the basis for emissions modeling and

projections for future years.]

B. Geographic area covered, base year, type of inventory (PM-10), pollutants

included (PM-10, others)

C. Brief discussion of contents of report

[Note: Include a paragraph or less describing each major report section. For

example, Section 2 summarized stationary point, area and mobile source

emissions by county. Section 3 describes stationary point source emissions and

includes a discussion of methods used to gather data, calculate annual and/or

seasonal emissions, and presents a summary of emissions by plant. Detailed

point source emissions data are presented in Appendix F. Section 4 discusses

...]

D. Discussion of automated data systems used (AFS/AMS, State system)

E. Major problems, deficiencies, portions of inventory not included

F. List of primary guidance documents and references used (EPA guidance documents,

AP-42, etc.)

G. List of contacts for each distinct portion of the inventory

IV. Summary

A. Emissions (annual and/or seasonal) of each pollutant by major category (point,

area, and mobile sources) in both tabular and graphical form; brief discussion

in footnote, etc. to clarify what each includes.

B. See example tables and graphics given in Example Emissions Inventory

Documentation for Post-1987 Ozone State Implementation Plans (SIPS) (U.S. EPA,

1989b).
29

(continued)
30

Table 4.1 Outline for EPA Recommended Format/Contents for PM-10 Emission Inventory

Reports (Continued)

V. Documentation of Emissions Methods/Data/Estimates

A. Point Source Emissions

1. discussions of procedures and methodologies including sample

calculations

2. example surveys/questionnaires

3. list of plants by primary product and total emissions

4. summary data for each plant by source classification code with

details in an appendix

5. point source emissions summary

B. Area Source Emissions

1. discussions of procedures and methodologies including sample

calculations

2. list of and emissions by source category

3. calculations and discussion for each source category

4. area source emissions summary

C. Mobile Source Emissions

1. discussion of procedures and methodologies including sample

calculations

2. list of vehicle classes and emissions

3. discussion of how VMT estimates were derived

4. discussion of key assumptions involved in the use of the PART5

model (or the latest available version)

5. calculations and discussion for each vehicle class

6. mobile source emissions summary

VI. Quality Assurance/Quality Control (QA/QC)

A. QA/QA plan - discussion of QA/QC methodologies used

B. Results from the application of the QA plan

C. QA procedures can also be discussed in individual source category sections

VII. Appendices

A. Lengthy data, calculations, documentation of methodologies/models

Notes: Annual and/or seasonal emissions shall be presented in the summary and sections

describing emissions.

All pages in the report (including appendices) shall be numbered. Sources of

information shall be referenced throughout. Include complete list(s) of

references within body of report (preferably at end of each section).

Margins of report shall be adequate so that copying of report will not lose

text, page numbers, or other important information.
31
22

used to determine emissions. Summary tables and graphics shall be prepared to

address just point source emissions.

For area and mobile sources, the report must state if any source

categories were not considered in the inventory and why. All of the source

categories covered shall be listed and the method used to determine emissions

identified. If an EPA method was used, but a different emission factor was

used, this must be noted. For all approaches used (EPA or otherwise), the

derivation of activity/commodity level data shall be thoroughly discussed. As

needed, supporting data can be put into appendices but the appendices shall be

fully explained and clearly linked back to the text discussion and emission

estimates. Like point sources, emission summaries shall be developed for area

and mobile sources. The summaries must reflect emissions by county and for the

entire nonattainment area.

As an aid to States in the preparation and checking of their inventories

prior to submittal to EPA, the Agency has been preparing a set of quality

review guidelines. These guidelines will contain what is essentially a

checklist of items that an inventory must contain or address in order for the

inventory to be considered acceptable for review by EPA. The guidelines will

address whether inventories meet developed specifications for completeness,

consistency (both internal and with national trends), reasonableness of

emission values, and emissions documentation.

States are required to design and implement a QA program to enhance the

overall reliability and accuracy of the PM-10 SIP emission inventories prepared

in response to the CAA. The inventory report shall have a separate section

that describes the implementation of the State's QA plan and the results

achieved by the QA program. For all source category types, the QA discussion

shall address the completeness of the inventory (e.g., are all of the EPArecommended area source categories accounted for), reasonableness of the

emission estimates (e.g., are estimates for a category consistent with some

other related parameter for the area), and relative accuracy of the data (e.g.,

do all of the individual county emission figures total to the sums given for

the whole area). The QA discussion must show the range of quality review that

was performed and how this review benefitted the inventory. This QA discussion

should reflect the planned QA program that was approved as a part of the IPP. 

The QA section should discuss how the QA plan was actually implemented, what

portion of the QA program did and did not work, the results of any internal or

external audits that were performed, and a general QA of the inventory data.

4.2 Data Management and Reporting

Emission inventory information for base year and periodic (if required)

inventories under the CAA shall be provided to EPA in electronic format. The

level of detail required to be reported to EPA is currently being determined

and may be the subject of future EPA guidance. States should consult their

Regional Office for the specific level of detail required for the electronic

reporting of data to EPA. If a State elects to use the EPA's AIRS, the level

of detail required for AIRS submittals would be sufficient for EPA data

reporting in coordination with EPA Regional Office requirements. The

requirements and instructions for data coding, updating, editing, storage, and
23

retrieval are specified in the AIRS User's Guide manuals. The AIRS User's

Guide manuals, along with several other reference documents for using AFS and

AMS, are available on the AIRS Bulletin Board System on the TTN. The AFS Data

System Helpline (1-800-367-1044) is available to handle technical system

questions, software malfunctions, and problems with the system. The AMS also

has a user's Help Line (1-800-333-7909) for assistance in all aspects of using

AMS. For more information, contact the EPA Regional Office.
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SECTION 5.0

REFERENCES

U.S. EPA, 1986: U.S. Environmental Protection Agency, Guideline On Air Quality

Models (Revised), EPA 450/2-78-027R, and its supplements, July 1986. 

(Codified in Appendix W of 40 CFR 51.)

U.S. EPA, 1987: U.S. Environmental Protection Agency, PM-10 SIP Development

Guideline, EPA 450/2-86-001, June 1987 and Supplement June 1988.

U.S. EPA, 1988a: Control of Open Fugitive Dust Sources, EPA-450/3-88-008,

September 1988.

U.S. EPA, 1988b: U.S. Environmental Protection Agency, Guidance for

Preparation of Quality Assurance Plans for Ozone/Carbon Monoxide

SIP Emission Inventories, EPA 450/4-88-023, December 1988.

U.S. EPA, 1989a: U.S. Environmental Protection Agency, Guidance Document

for Residential Wood Combustion Control Measures, EPA 450-2-89-015,

September 1989.

U.S. EPA, 1989b: U.S. Environmental Protection Agency, Example Emissions

Inventory Documentation for Post-1987 Ozone State Implementation

Plans (SIPS), EPA-450/4-89-018, October 1989.

U.S. EPA, 1990: U.S. Environmental Protection Agency, Guideline on Air

Quality Models (Revised), memorandum from Joseph Tikvart and Robert

Bauman, July 5, 1990.

U.S. EPA, 1991a: U.S. Environmental Protection Agency, PM-10 Moderate

Area SIP Guidance: Final Staff Work Product, memorandum from John

Calcagni, April 2, 1991.

U.S. EPA, 1991b: U.S. Environmental Protection Agency, Nonroad Engine and

Vehicle Emission Study -- Report, EPA-21A-2001, November 1991.

U.S. EPA, 1992: U.S. Environmental Protection Agency, Background

Information Document for Prescribed Burning Best Available Control

Measures, EPA 450/2-92-003, September 1992.

U.S. EPA, 1993a: U.S. Environmental Protection Agency, PM-10 Serious Area

SIP Guidance: Final Staff Work Product, memorandum from Joseph W.

Paisie, September 24, 1993.

U.S. EPA, 1993b: U.S. Environmental Protection Agency, PM-10 Guideline

Document and Appendix, EPA 452/R-93-008, April 1993.
25
26

APPENDIX A

INVENTORY PREPARATION PLAN (IPP) REVIEW CHECKLIST

The purpose of this checklist is to provide a decision tool for

determining if an IPP meets EPA's minimum requirements. The questions marked

with an asterisk (*) are considered crucial to an acceptable IPP, but are not

required. Those questions not so marked are considered desirable items.

1.0 APPROACH

*1.1 Does the IPP indicate whether it was prepared for the purposes of a PM-10

SIP inventory?

Yes No Comments

*1.2 Does the IPP define the nonattainment area(s) that the inventory will

address, and indicate the nonattainment classification for the area(s)?

Yes No Comments

 1.3 Are the groups/persons responsible for the inventory and the

groups/persons compiling the inventory specified?

Yes No Comments

 1.4 Does the IPP contain a suitable outline for content and organization

review of the planned inventory report?

Yes No Comments
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28

*1.5 Does the IPP contain schedules of submission dates for draft and final

inventories or inventory components if the State plans to submit the

inventory in component pieces?

Yes No Comments

*1.6 If the IPP covers multiple nonattainment areas, are differences in the

approach for the nonattainment areas clearly defined?

Yes No Comments

 1.7 Does the IPP address which source categories of PM-10, regardless of

size, will be inventoried?

Yes No Comments

*1.8 Are stationary point, stationary area, on-road mobile, and nonroad

mobile, where applicable, addressed?

Yes No Comments

*1.9 Does the IPP summarize the basis for the inventory and the source(s) of

basic emissions documentation information for each principal inventory

component (point, area, on-road mobile, etc.)?

Yes No Comments
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2.0 POINT SOURCES

*2.1 Does the IPP define how all pertinent emission sources will be identified

and located?

Yes No Comments

 2.2 Does the IPP describe how point source activity levels and associated

parameters will be developed and discuss how these data will be used to

calculate emission estimates?

Yes No Comments

*2.3 Does the IPP discuss how and when statewide point source reporting to the

EPA will be conducted and how it will be coordinated with reporting for

nonattainment area sources?

Yes No Comments

*2.4 Does the IPP indicate whether rule effectiveness (RE) was applied and

discuss the basis for its application if it was included in the emission

calculations?

Yes No Comments

 2.5 Does the IPP discuss what emission control efficiencies will be based on?

Yes No Comments
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31

3.0 STATIONARY AREA AND NONROAD MOBILE SOURCES

*3.1 Does the IPP explicitly state which source categories will be addressed?

Yes No Comments

*3.2 Does the IPP explicitly state which source categories from EPA's emission

inventory requirements will not be addressed and provide justification?

Yes No Comments

*3.3 For source categories included, does the IPP indicate or reference the

approach used to calculate emissions?

Yes No Comments

*3.4 If there are alternate EPA methods for a category, does the IPP clearly

indicate the method the State intends to use?

Yes No Comments

*3.5 Are the major assumptions stated for approaches that differ from EPA's

guidance?

Yes No Comments

*3.6 Does the IPP define the source of activity level data?
32

Yes No Comments
33

*3.7 If RE was applied, does the IPP discuss the basis for the application

of RE?

Yes No Comments

*3.8 Does the IPP discuss what emission control efficiencies will be based on?

Yes No Comments

4.0 ON-ROAD MOBILE SOURCES

*4.1 Does the IPP provide a clear indication of how the State intends to

develop a VMT estimate?

Yes No Comments

*4.2 Does the IPP indicate that PART5 will be used to develop mobile source

emission factors?

Yes No Comments

*4.3 If PART5 will not be used, does the IPP discuss the alternate emissions

estimation methods?

Yes No Comments

*4.4 Are the key assumptions for the PART5 model identified (i.e., vehicle

speed)?
34

Yes No Comments

 4.5 Does the IPP specify the vehicle classes that will be covered?

Yes No Comments

5.0 MODELING

*5.1 Is the modeling inventory and the modeling approach for the attainment

demonstration discussed in the IPP?

Yes No Comments

 5.2 Is the modeling area defined?

Yes No Comments

 5.3 Does the IPP indicate when initial modeling inventory data will be

submitted?

Yes No Comments

 5.4 Does the IPP discuss early coordination between inventory and modeling

personnel in inventory planning?

Yes No Comments
35

 5.5 Does the IPP discuss how the temporal and spatial resolution will be

determined for model inputs?

Yes No Comments
36

6.0 DOCUMENTATION

*6.1 Does the IPP clearly describe how the State plans to present, document,

and submit the inventory to EPA?

Yes No Comments

 6.2 Does the IPP discuss how emission estimates will be summarized for each

nonattainment area?

Yes No Comments

*6.3 Was the Regional Office contacted to establish the specific level of

detail required for the electronic reporting of data to EPA, and does the

IPP specify the computerized methods for compiling and submitting the

data to EPA?

Yes No Comments

*6.4 If a State uses or plans to use AIRS, does the IPP indicate how data will

be input into AFS and AMS?

Yes No Comments

7.0 QUALITY ASSURANCE (QA) PLAN

*7.1 Does the IPP contain a QA plan for the inventory?

Yes No Comments
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38

*7.2 Does the QA plan describe the overall QA program that the State intends

to use during compilation of the inventory?

Yes No Comments

8.0 QA POLICY STATEMENT

*8.1 Does the QA plan contain a Policy Statement with a formal declaration of

management's commitment to the development and implementation of the QA

program?

Yes No Comments

*8.2 Does the Policy Statement indicate that there is a commitment to develop

a quality emission inventory, including the allocation of resources for

the QA program?

Yes No Comments

*8.3 Is the Policy Statement signed by the QA Coordinator and Agency

Administrator?

Yes No Comments

9.0 SUMMARY

 9.1 Does the QA plan's summary include an overview of the major components of

inventory development?

Yes No Comments
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40

*9.2 Does the summary include a description of the flow of the inventory data

through the Agency or refer to such a flow chart elsewhere in the IPP?

Yes No Comments

*9.3 Does the summary indicate the critical points at which QA is applied

during the development of the inventory?

Yes No Comments

 9.4 Are the data QC techniques given in the summary, including an indication

of the frequency that they will be applied?

Yes No Comments

 9.5 Does the summary contain the objectives for emission inventory

development?

Yes No Comments

 9.6 Does the summary discuss the constraints relative to the development of

the emission inventory (i.e., given personnel, time, resources, data

processing capabilities)?

Yes No Comments

*9.7 Does the summary include an organizational chart showing the technical as

well as QA personnel?
41

Yes No Comments
42

*9.8 Does the organizational chart show the QA coordinator reporting to upper

management not directly involved in the development of the inventory?

Yes No Comments

*9.9 Does the summary provide the names and telephone numbers of the QA

coordinator and directors?

Yes No Comments

10.0 TECHNICAL CONSIDERATIONS--PLANNING

 10.1 Does the QA plan contain a schedule of QA activities?

Yes No Comments

 10.2 Are the responsibilities of the QA Coordinator given?

Yes No Comments

 10.3 Is the personnel training program explained in the QA plan?

Yes No Comments

*10.4 Are the checkpoints for problem detection given in the QA plan?

Yes No Comments
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44

*10.5 Does the QA plan show that the QA/QC program includes assessing data

completeness and standard range checking?

Yes No Comments

*10.6 Does the QA plan give the critical data elements relative to assessing

the completeness of the source data?

Yes No Comments

11.0 TECHNICAL CONSIDERATIONS--DATA COLLECTION AND ANALYSIS

*11.1 Does the QA plan explain data collection procedures and QA/QC procedures

used to insure quality data were collected?

Yes No Comments

 11.2 Does the QA plan indicate what QA/QC procedures will be implemented to

account for all sources?

Yes No Comments

*11.3 Does the QA plan describe QA/QC procedures that will prevent double

counting of sources?

Yes No Comments
45

*11.4 Does the QA plan explain how the quality and accuracy of the calculations

will be evaluated for:

- Consistency in methodology?

Yes No Comments

- Review of engineering judgement?

Yes No Comments

- Accuracy of units and unit conversions?

Yes No Comments

- Transposition of figures?

Yes No Comments

- Misinterpretations of the use of emissions factors?

Yes No Comments

*11.5 Does the QA plan explain how the completeness, reasonableness,

reliability, and consistency in the use of equations for specific methods

will be evaluated?

Yes No Comments
46
47

 11.6 Does the QA plan indicate that the person responsible for evaluating the

accuracy of the calculations is not directly involved in the inventory

development?

Yes No Comments

12.0 TECHNICAL CONSIDERATIONS--DATA HANDLING

*12.1 Does the QA plan explain the data management procedures (i.e., coding,

tracking, securing, storing on disks)?

Yes No Comments

*12.2 Does the QA plan include procedures which explain how data will be

corrected and these corrections tracked?

Yes No Comments

*12.3 Are data documentation procedures given (i.e., use of notebooks,

computers, work sheets)?

Yes No Comments

13.0 QA REPORTING

*13.1 Does the QA plan indicate how applicable data checks (e.g., consistency,

completeness, reasonableness, and proofing) will be reported in the

inventory?

Yes No Comments
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14.0 QA AUDITS

*14.1 Does the QA plan contain a statement that the Agency is willing to be

audited by EPA?

Yes No Comments

 14.2 Does the QA plan indicate that the QA program includes routine

assessments of the effectiveness of the inventory development procedures

(i.e., internal audits)?

Yes No Comments

 14.3 Does the QA plan indicate the frequency of internal audits?

Yes No Comments

 14.4 Are the objectives of the audits given?

Yes No Comments

 14.5 Does the audit procedure include documentation of the findings and

periodic reports to management?

Yes No Comments
TECHNICAL REPORT DATA

(Please read Instructions on reverse before completing)

1. REPORT NO.

 EPA-454/R-94-033

2. 3. RECIPIENT'S ACCESSION NO.

4. TITLE AND SUBTITLE

 PM-10 Emission Inventory Requirements Final Report

5. REPORT DATE

 September 1994

6. PERFORMING ORGANIZATION CODE

7. AUTHOR(S)

 Randy Strait

8. PERFORMING ORGANIZATION REPORT NO.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

 E. H. Pechan & Associates, Inc.

 3500 Westgate Drive, Suite 103

 Durham, NC 27707

10. PROGRAM ELEMENT NO.

11. CONTRACT/GRANT NO.

 68-D2-0159, WA 13

12. SPONSORING AGENCY NAME AND ADDRESS

 Emission Inventory Branch (MD-14)

 Sulfur Dioxide/Particulate Matter Programs Branch (MD-15)

 U. S. Environmental Protection Agency

 Research Triangle Park, NC 27711

13. TYPE OF REPORT AND PERIOD COVERED

 Final

14. SPONSORING AGENCY CODE

15. SUPPLEMENTARY NOTES

16. ABSTRACT

This document describes the emission inventory requirements that are contained, either explicitly or implicitly, in the C

1990 (CAA) for those areas that are required to submit a State Implementation Plan (SIP) for demonstrating attainmen

Quality Standard (NAAQS) for PM-10. The guidance in this document pertains to PM-10 moderate nonattainment a

reclassified as serious nonattainment areas. The purposes of the document are to (1) identify the types of inventories r

regulatory requirements pertaining to submission of these inventories; (3) describe the objectives, components, and ult

and (4) define documentation and reporting requirements for the inventories.

17. KEY WORDS AND DOCUMENT ANALYSIS

a. DESCRIPTORS b. IDENTIFIERS/OPEN ENDED TERMS c. COSATI Field/Group

 Emissions

 Particulate

 Emission Inventories

 PM-10

 Guidance

18. DISTRIBUTION STATEMENT

 Unlimited

19. SECURITY CLASS (Report)

 Unclassified

21. NO. OF PAGES

45

20. SECURITY CLASS (Page)

 Unclassified

22. PRICE

EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION IS OBSOLETE