svEPA
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-450/4-81-026a
September 1981
Air
Procedures for Emission
Inventory Preparation
Volume I: Emission
Inventory Fundamentals
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NOTICE
The Procedures for Emission Inventory Preparation consists of these
five volumes.
Volume I - Emission Inventory Fundamentals
Volume II - Point Sources
Volume III - Area Sources
Volume IV - Mobile Sources
Volume V - Bibliography
They are intended to present emission inventory procedures and
techniques applicable in State and local air programs, and for con-
tractors and other selected users. The object is to provide the best
available and "state of the art" information. For some areas, however,
the available source information and data either may allow more precise
procedures and more accurate estimation of emissions or may not be amen-
able to the use of these procedures. Therefore, the user is asked to
share his knowledge and experience by providing comments, successfully
applied alternative methods or other emission inventory information
useful to other users of these volumes. Please forward comments to the
U.S. Environmental Protection Agency, Air Management Technology Branch,
(MD-14), Research Triangle Park, NC 27711. Such responses will provide
guidance for revisions and supplements to these volumes.
Other U.S. EPA emission inventory procedures publications:
Procedures for the Preparation of Emission Inventories for
Volatile Organic Compounds, Volume I, Second Edition,
EPA-450/2-77-028, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1980.
Procedures for the Preparation of Emission Inventories of
Volatile Organic Compounds, Volume II: Emission Inventory
Requirements for Photochemical Air Quality Simulation Models,
EPA-450/4-79-018, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1979.
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EPA-450/4-81-026a
Procedures for Emission Inventory Preparation
Volume I: Emission Inventory Fundamentals
by
Monitoring and Data Analysis Division
Office of Air Quality Planning and Standards
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air, Noise and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
September 1981
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This document is issued by the Environmental Protection Agency to report
technical data of interest to a limited number of readers. Copies are
available free of charge to Federal employees, current EPA contractors
and grantees, and nonprofit organizations - in limited quantities - from
the Library Services Office (MD-35), U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina 27711; or, for a fee, from the
National Technical Information Service, 5285 Port Royal Road, Springfield,
Virginia 22161.
This report was furnished to the Environmental Protection Agency by GCA
Corporation, Bedford, Massachusetts 01730, in fulfillment of Contract
No. 68-02-3087. The contents of this report are reproduced herein as
received from GCA Corporation. The opinions, findings and conclusions
expressed are those of the author and not necessarily those of the
Environmental Protection Agency.
**»•=*,»...
*->' •
Publication No. EPA-450/4-81-026a
ii
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TABLE OF CONTENTS
Section
List of Figures v
List of Tables vi
1.0 INTRODUCTION 1-1
1.1 Background 1-1
1.2 Emission Inventory Overview 1-6
1.3 Purpose and Organization of the Procedures for
Emission Inventory Preparation Series 1-8
1.3.1 Volume I: Emission Inventory Fundamentals . 1-9
1.3.2 Volume II: Point Sources 1-9
1.3.3 Volume III: Area Sources 1-9
1.3.4 Volume IV: Mobile Sources 1-10
1.3.5 Volume V: Bibliography 1-10
2.0 MANAGEMENT AND PLANNING OF THE EMISSION INVENTORY PROGRAM . . 2-1
2.1 Emission Inventory Program Organizational
Structure 2-2
2.1.1 Agency Organizational Structure 2-2
2.1.2 Emission Inventory Task Force Organizational
Structure 2-4
2.2 Planning 2-6
2.2.1 General Planning Considerations 2-6
2.2.1.1 End Uses of the Inventory .... 2-7
2.2.1.2 Sources of Emissions 2-7
2.2.1.3 Point/Area Source Distinctions . . 2-8
2.2.1.4 Geographical Area/Spatial
Resolution 2-9
2.2.1.5 Temporal Resolution 2-9
2.2.1.6 Data Collection Methods 2-9
2.2.1.7 Special Procedures 2-10
2.2.1.8 Emission Projections 2-10
2.2.1.9 Status of Existing Inventory . . . 2-11
2.2.1.10 Data Handling 2-11
2.2.1.11 Quality Assurance 2-12
2.2.1.12 Documentation 2-15
2.2.1.13 Emission Inventory Manpower
Requirements 2-15
2.2.2 Specific Procedures 2-16
2.2.3 Project Schedules 2-18
2.2.3.1 Scheduling Techniques 2~18
2.2.3.2 Task Sequence 2-19
2.2.3.3 Task Schedules ..... 2-21
2.2.3.4 Example of Project Scheduling . . 2-23
111
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Section
3.0 APPLICATIONS AND USERS
3.1 Applications of the Inventory
3.1.1 State Implementation Plan (SIP) Preparation
and Review
3.1.2 Strategies Development
3.1.3 Dispersion Modeling
3.1.4 Reasonable Further Progress (RFP)
3.1.5 Prevention of Significant Deterioration . .
3.1.6 Offsets
3.1.7 Environmental Impact Analysis
3.1.8 Ambient Monitoring Network Design
3.1.9 Enforcement and Compliance
3.1.10 Emission Trends
3.1.11 Energy Analysis .
3.1.12 Research
3.2 Users of the Inventory
3.2.1 State and Local Agencies
3.2.2 Citizen Use
3.2.3 Government Contractors/Institutional . . .
3.2.4 Federal (Non-EPA)
4.0 INVENTORY DATA REQUIREMENTS
4.1 Point Sources
4.1.1 Plant Level
4.1.2 Process Level
4.1.3 Point Level
4.2 Area Sources . .
4.2.1 Air Quality Control Region Level . .
4.2.2 County Level
4.2.3 Grid Level
4.3 Mobile Sources
4.3.1 Air Quality Control Region and County
Levels
4.3.2 Grid Level
4.4 Temporal Resolution
5.0 EMISSION INVENTORY DATA COLLECTION
5.1 Information Sources
5.2 Data Collection
5.2.1 Questionnaires ....
5.2.2 Filling Data Gaps
5.3 Calculation of Emissions
5.4 Data Assessment and Quality Assurance • •
5.5 Emission Inventory Maintenance and Update
6.0 PRESENTATION OF INVENTORIES/DATA SYSTEMS
6.1 Presentation Techniques
6.2 Summary of Inventory Data Systems
7.0 MANPOWER/RESOURCE ALLOCATION MODEL
APPENDIX A - DEFINITIONS
IV
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LIST OF FIGURES
Figure Page
2-1 A typical organizational structure of an air pollution
control agency 2-3
2-2 Example of a portion of a network 2-22
2-3 Project schedule with milestones 2-24
2-4 Program schedule chart ..... 2-25
3-1 Flow diagram for the development of a control
strategy 3-4
5-1 Sample format for a questionnaire cover letter .... 5-5
5-2 Sample of questionnaire general instruction sheet . . 5-6
6-1 Emission Inventory System - Source Record 6-2
6-2 New York - AIR 100 Source Record 6-3
6-3 Nationwide emission estimates, 1977 • 6-5
6-4 NEDS annual fuel summary report 6-6
6-5 Mr pollutant emissions in AQCR 215-Metropolitan
Dallas - Fort Worth (TX) 6-7
6-6 Air emissions of pollutants in the United States . . . 6-8
6-7 An example of pie chart displaying the distribution
of VOC emissions in a survey area 6-9
6-8 Energy consumption by economic sector ........ 6-10
6-9 Total annual emission estimates for U.S. municipal
incineration systems 6-11
6-10 Historical particulate emissions by source
category 6-13
6-11 Energy consumption by fuel use and consumer
category 6-14
6-12 Particulate emission density, by state 6-15
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Figure Page
6-13 Nitrogen oxide emission density by county 6-16
6-14 Location and emission rate of all plants
emitting S02 6-17
7-1 Time requirement model—graphical representation . . • 7-2
LIST OF TABLES
Table Page
1-1 National Emissions, 1977 1-5
3-1 PSD Industrial Categories 3-7
3-2 Air Quality Increments ..... 3-8
5-1 Example of Internal Consistency Checks for Boilers • • 5-10
5-2 Errors and Error Sources in the Emission Inventory
Process 5-11
5-3 Examples of Preventive Quality Assurance
Techniques 5-13
5-4 Examples of Corrective Quality Assurance
Techniques 5-15
7-1 Time Requirement Model (TREM) Summary 7-4
VI
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1.0 INTRODUCTION
This volume is the first of a five volume series designed to assist
personnel of air pollution control agencies in preparing and maintaining
emission inventories. The next three volumes address specific areas of the
19
Inventory process, namely the preparation of inventories of point,x area,^
and mobile^ sources, respectively; the fifth volume^ is a bibliography of
pertinent publications relating to inventorying activities. Emphasis in this
series is placed on a systematic approach to identifying emission data
requirements and sources; collecting and processing the required Information;
and presenting the data in a format consistent with the intended application
of the inventory. Although specific procedures for preparing the emission
inventory are provided whenever possible, available options and the reasons
for them are identified and discussed.
Specifically, this volume Is presented as a reference guide for managers
and planners of state and local air quality control programs. In conjunction
with the other volumes, it serves as a resource for management's use in:
1. Planning an emission inventory,
2. Establishing an agency organization to carry on the emission
inventory programs, and
3. Establishing documented procedures and quality assurance activities
for emission Inventory programs.
All volumes of this manual will be updated periodically to reflect current
practices in inventory preparation and management.
1.1 BACKGROUND
An emission inventory is, ideally, a comprehensive, accurate and current
accounting of air pollutant emissions and associated data from sources within
the inventory area over a specific time Interval. In addition to emission
data, the information contained in the inventory data system will Include
source, dispersion modeling, pollution control and compliance information
which can be used by the agency to determine the present and projected effect
of emissions on ambient air quality.
Emission inventories have been used for many years by state and local
agencies to quantify pollutant emissions within their jurisdictions. Together
with ambient monitoring data, inventory emission estimates have been used as a
direct indicator of annual changes in air quality. The inventory is also
routinely used in the conduct of many air quality programs. For example,
compliance inspections typically begin with a review of inventory-provided
source data and the siting of ambient monitoring stations is often dependent
upon emission information maintained in the inventory.
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Many state agencies initially developed emission inventories to assist
them in the development of State Implementation Plans (SIPs). These plans
were required by Section 110 of the Clean Air Act and set forth the state's
strategy for attaining and maintaining national ambient air quality standards
(NAAQS). The use of an inventory became mandatory for certain areas with
adoption of the Clean Air Act amendments in 1977. The nonattainment plan
provisions (Section 172) of the amendments require the use of an inventory to
document emissions in nonattainment areas.
To meet the reporting requirements of the nonattainment plan provisions,
states are required to provide an emission inventory of point and area sources
for the pollutant of nonattainment. Currently the EPA is requesting that
states submit the emission inventory of the nonattainment areas 1 year after
the date their revised SIP was submitted to the EPA Regional Office and
resubmit annually for as long as the area retains Its nonattainment
designation. The EPA has not formally proclaimed a specific reporting format,
however, the data submitted should be readily converted to the National
Emissions Data System (NEDS) format.5
In addition, under the published provisions of Title 40 of the Code of
Federal Regulations Part 51 (40 CFR 51), Subpart 51.321, state agencies are
required to report annually point source emission data for certain sources to
the appropriate regional office of the EPA. Point sources subject to the
annual emission reporting requirements are:
any facility that actually emits a total of 90.7 metric tons (100 tons)
per year or more of particulate matter, sulfur oxides, hydrocarbons, or
nitrogen oxides;
any facility that actually emits a total of 907 metric tons (1000 tons)
per year or more of carbon monoxide; and
any facility that actually emits a total of 4.5 metric tons (5 tons) per
year or more of lead or lead compounds measured as elemental lead.
In addition, reporting of annual emissions from Individual emission points
within a facility Is required for those points for which:
actual emissions of particulate matter, sulfur oxides, hydrocarbons and
nitrogen oxides equal or exceed 22.7 metric tons (25 tons) per year;
Actual emissions of carbon monoxide equal or exceed 227 metric tons (250
tons) per year', and,
Actual emissions of lead, or lead compounds measured as elemental lead,
equal or exceed 4.5 metric tons (5 tons) per year.
The provisions of 40 CFR 51 require that particulate matter, sulfur
oxides, carbon monoxide, nitrogen oxides, and hydrocarbon emission data be
submitted in the format of the NEDS point source coding forms. Emission data
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for lead or lead compounds measured as elemental lead must be submitted in the
format of the Hazardous and Trace Emissions System^ (HATREMS) point source
coding forms.*
State agencies are required to submit emissions data in the annual report
for any point source for which one or more of the following conditions occurs:
A source achieves compliance at any time within the reporting period with
any regulation of an applicable plan,
A new or modified source receives approval to construct during the
reporting period or begins operating during the reporting period,
A source ceases operations during the reporting period, and
A source's emissions have changed more than 5 percent from the most
recently submitted emissions data.
Concerning the last requirement, if it is determined that emissions from any
point source have not changed more than 5 percent from the most recently
submitted emission data, the state shall only update the year of record of the
previously reported emission data.
While the development and maintenance of comprehensive emission
inventories are specifically mandated by the Clean Air Act for nonattainment
areas, it is apparent that numerous other sections of the Act establish
requirements which will also compel regulatory control agencies to compile
source/emission data in some form. Specifically, source/emission inventory
information will be necessary to:
Monitor sources for emissions (with exemptions under control of pollution
from federal facilities (Section 118), enforcement orders under federal
enforcement (Section 113(d)) suspension orders under implementation plans
(Section 110(f) or (g)), or orders under primary nonferrous smelter
orders (Section 119)) which may be responsible for the failure of the
state implementation plan to accomplish the objectives of achieving the
primary and secondary NAAQS (Section 110(a)(3)(c)).
Determine the extent to which State Implementation Plans for attainment
of the NAAQS for 862 and particulate are dependent upon gas, oil and/or
low sulfur coal supplies as required by the Assurance of Adequacy of
State Plans (Section 124).
*There are no requirements in 40 CFR 51 for the reporting of area source
emissions.
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Provide data for air quality modeling as described in Standardized Air
Quality Modeling (Section 320(d)) necessary to carry out the prevention
of significant deterioration (PSD) required by Part C— Prevention of
Significant Deterioration of Air Quality (Section 160-169).
Inventory "Major Sources" defined in Definitions (Section 169) along with
start of construction and start of operation dates to determine their
contribution to baseline concentrations defined in Definitions (Section
169), or increments and ceilings as defined in Increments and Ceilings
(Section 163).
Identify "Major Sources" described in Increments and Ceilings (Section
163(3)) when emissions may be exempted (temporarily or otherwise) from
deterioration compliance with the maximum allowable increases in ambient
concentrations of an air pollutant.
Monitor increases and decreases of individual source emissions as
mentioned in Nonattainment Areas (Section 129) during the interim period
until new SIPs are approved, and
Exchange data among states as may be required under Interstate Pollution
Abatement (Section 126).
EPA requires that emission data be reported to them in NEDS format. NEDS
specified data and NEDS format must therefore be considered at a minimum by a
local agency interested in designing and implementing its own system. NEDS is
a component of the federal air information system, AEROS (Aerometric and
Emissions Reporting System).^ AEROS was established by the EPA to serve as
a management information system for its air pollution programs.
NEDS was the first federally-sponsored air pollutant emission inventory
system, and has served as a model for many subsequent local inventory
systems. NEDS is a computerized data handling system which compiles, stores,
and reports on information relating to sources of any of the following five
criteria pollutants: particulates, SOX, NOX, CO and hydrocarbons. A
summary table taken from the NEDS 1977 National Emission Report^ shows the
annual United States emissions of pollutants by source category (Table 1-1).
In NEDS, a major distinction is made between two types of sources: point
sources and area sources. Point sources are stationary sources large enough
to be identified and individually maintained in the inventory. Area sources
are those stationary and mobile sources which individually do not qualify as a
point source and are too small and numerous to be maintained separately in the
inventory. In the NEDS, area sources are considered collectively on a county
basis. Area sources include small stationary sources such as gasoline service
stations, domestic and commercial heating, and all mobile sources. However,
because of their distinct characteristics, mobile sources are treated
separately in this series as a separate component of the emission inventory.
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The EPA Regional Offices are responsible for receiving, processing and
editing NEDS data. The Regional Offices and the National Air Data Branch of
OAQPS also provide automatic data processing assistance to state and local
agencies in areas such as data processing and auditing and personnel
training. A majority of the states are currently compiling their inventory
data on the EPA-developed Emission Inventory System/Point Source Subsystem
(EIS/PS)' and the Emission Inventory System/Area Source Subsystem
(EIS/AS)8 of the Comprehensive Data Handling System (CDHS). Through EPA,
programs are available that convert CDHS data to the NEDS point source and
area source formats and allows data to be added, changed, and deleted. The
CDHS subsystem programs satisfy state requirements for reporting source
emission data annually to EPA.
The Aerometric Information Reporting System (AIRS) has been proposed by
EPA to replace the existing AEROS and CDHS systems. This system will
integrate all data pertaining to Air Quality Siting, Raw Air Quality Data, Air
Quality Summary Information, Point and Area Source Engineering and Enforcement
Information, and Air Quality Assurance Information. AIRS will provide state
agencies with direct access to the data base for editing and validation of
input data and for report retrievals. The system will also provide increasing
report capabilities for all users (such as graphics and statistical analysis
packages) and will incorporate a more flexible system design capable of
meeting changing aerometric data requirements as well as allowing states to
define and store unique sets of data in addition to those data required to be
reported to EPA. A target date of 1985 is set for operation of this new
system.
1.2 EMISSION INVENTORY OVERVIEW
Because an emission inventory is the repository for pollutant related
data, it is the key element in all agency programs aimed at improving and
maintaining air quality within the Agency's jurisdiction. The impact of
control strategies on emissions can be directly assessed and the resulting
impact on ambient air quality determined by dispersion modeling. Although the
major purpose of the Inventory is to quantify all emissions within the total
jurisdiction, the Agency may at certain times focus its activities on specific
pollutants; e.g., nonattainment pollutants, or special geographical areas,
such as areas of high emission density. Once the key sources and source
categories are identified by management, the source and emission data are
obtained by means of survey questionnaires, source inspections, permit
application reviews, statistical data source analysis or other means. Actual
quantification of emissions is accomplished through the use of source tests,
material balances, or the application of emission factors. Once this initial
quantification effort is completed, the Inventory must be regularly maintained
by updating source activity information and by adding or deleting sources as
such events occur. Emission inventory maintenance efforts must be planned to
ensure that the inventory data are current and accurate and sufficient for the
needs of the agency.
The emission inventory process can be divided into the following
components:^
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Planning—Mangement must identify emission inventory requirements
associated with agency programs and integrate the inventory activities
into their overall program by assigning an inventory coordinator and
establishing a work group structure. The various planning aspects
discussed in the following chapter should all be considered prior to
initiation of the actual data gathering phase of the inventory effort.
Documented written procedures must be developed for all inventory
activities including source identification, data collection and analysis,
data reduction and insertion into the source file record format,
presentation of the data, and quality assurance. All procedures should
be documented for approval by management and the technical staff prior to
the initiation of data gathering activities.
Data Collection—A major distinction involves which sources should be
considered point sources in the inventory and which should be considered
area sources. Fundamentally different data collection procedures are
used for these two source types. Individual plant contacts are used to
collect point source data, whereas collective information is generally
used to estimate area source activity and emissions for area source
categories. Much more detailed data are collected and maintained on
point sources.
Data Analysis—All source data collected must be checked for completeness
and accuracy. Calculation of emissions, using source test data, material
balance and emission factors, and examination of process information
should be undertaken to validate the data or to identify potential
errors. Recontacting of specific point sources and sources of area
source activity data may be necessary to correct deficiencies.
Data Reduction and Formatting—The validated data and source infomration
must be reduced to a predesigned uniform source format and entered into
the data file. A computerized data file is recommended to facilitate
calculations and error checks us'ig documented quality assurance
procedures.
Data Reporting—Various report formats and presentation styles need to be
investigated and formats adopted consistent with the data handling system
and the intended applications of the inventory data.
An emission inventory data system is an information recordkeeping and
processing system designed around emission data. The system may be either
manual or automatic, but must be designed to handle all source information
deemed by the agency to be relevant to their programs. Automated system
designs must incorporate retrieval capabilities that allow the agency to
segregate all sources with a common operating or emission characteristics
(pollutant emission rate, process type, location, etc.). The system must be
sufficiently flexible to allow the recording of point, area, mobile, and
fugitive dust source data.
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The following Information is typically required for point source and area
sources. (Data requirements for State Implementation Plans are specified in
40 CFR 51, Appendix E and F for point and area sources, respectively.)
Point Source Data
General source information—Name, address, type of source, year
of record, comments, etc.
Emission-related data—Operating or production rate, estimated
emissions, EPA calculated emissions, control device type and
efficiency, etc.
Modeling parameters—UTM coordinates of source, stack height, and
diameter, exhaust gas temperature, and flow rate.
Compliance-related information—Allowable emissions, applicable
control regulations, compliance status, and schedules, etc.
Area Source Data
General source information—Name and location of area (county)
source, population, year of record.
Activity levels—Countywide activity level of each area source
category (e.g., tons of coal burned in all residential space
heating equipment in a county).
Emission data—Emission estimates for the entire county, for each
pollutant and for each area source category.
Whatever the intended use of the immediate inventory activity, it must be
conducted using standard documented methods. It is also necessary that
standard procedures for maintaining and updating the comprehensive inventory
be developed to ensure that the inventory remains accurate and complete.
1.3 PURPOSE AND ORGANIZATION OF THE PROCEDURES FOR EMISSION INVENTORY
PREPARATION SERIES
The emission inventory preparation series consists of five separate
volumes and serves as a comprehensive technical reference manual for
establishing an emission inventory of point, area and mobile sources. The
series, prepared for use by state and local air quality control agencies,
presents the most recent techniques for obtaining, quantifying and handling
emission related data. The series consists of the following volumes:
Volume I—Emission Inventory Fundamentals
Volume II—Point Sources
Volume III—Area Sources
Volume IV—Mobile Sources
Volume V—Bibliography
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Each volume defines the rationale and procedures necessary to prepare or
upgrade an emission inventory and includes examples to assist the user in
understanding specific methods and procedures. An important feature of the
multivolume series is the fact that it can be updated periodically to include
new information on pollutants, source categories, emission factors and data
handling as it becomes available.
1.3.1 VOLUME I: EMISSION INVENTORY FUNDAMENTALS
Emphasis is placed in this volume on the need for careful planning to
ensure that the emission inventory is accurate, complete and current and is
consistent with agency requirements, Including manpower and schedules. The
many applications and users of the inventory are identified and data
requirements for various levels of a comprehensive inventory are noted. The
process of collecting and quantifying emission data is next addressed
including a section on data analysis and validation, quality assurance and
inventory maintenance. General techniques for displaying inventory
information are presented with several illustrative examples shown. Finally,
this volume presents a manpower resource model in which the time required to
complete each individual task of inventory preparation is estimated. This
model will assist managers in estimating inventory manpower requirements. An
appendix to Volume I includes a glossary of terms employed by air pollution
control agencies in conducting emission inventories (and other regulatory
functions). This list of terms provides a uniform set of definitions which
can be consistently and logically applied during the inventory process.
1.3.2 VOLUME II: POINT SOURCES
Volume II provides methods and techniques for identifying and quantifying
the emissions from point sources of pollution. Techniques for identifying and
contacting all major emitters, specific data procurement techniques, methods
of data analysis and validation are presented, including procedures for the
calculation of emissions using emission factors, process material balances and
engineering appraisals. Reporting techniques specific to point sources are
identified followed by a general discussion of problems encountered with
specific source groups, such as combustion sources, the chemical process
industry and the metallurgical industry. Example questionnaires of both a
general and industry-specific nature are provided in the appendicies.
1.3.3 VOLUME III: AREA SOURCES
Volume III outlines the methods of collecting and handling emission data
from sources too small and/or too numerous to be surveyed individually,
collectively known as area sources. Procedures are discussed which will
assist the user in identifying area source categories and important reference
materials which can be used to determine the activity levels associated with
these source categories. Emission factors, emission calculations, pollutant
allocation and projection techniques, and methods of data presentation are
identified and reviewed to assist the agency in the preparation and
maintenance of the area source emission inventory. Specific emphasis is
placed on the major area source categories: combustion sources, solid waste
disposal, fugitive dust sources and solvent sources.
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1.3.4 VOLUME IV: MOBILE SOURCES
This volume concentrates on both traditional and nontraditional mobile
sources of pollution. Both traditional sources, such as on-highway vehicles
and airports, and the less common sources, such as off-highway vehicles,
aircraft, railroads, and vessels, are discussed in detail. For each category
the data requirements, sources of data, procurement techniques and calculation
methods are presented. State-of-the-art computer dispersion modeling
techniques for this group of sources are discussed.
1.3.5 VOLUME V: BIBLIOGRAPHY
This volume presents an extensive listing of reference material currently
available In the literature which will assist the user in the development of
the emission inventory. A concise abstract outlining the pertinent emission
inventory information is provided for each reference cited.
References for Chapter 1.0
1. Procedures for Emission Inventory Preparation - Volume II; Point Sources,
EPA-450/4-81-026b, U.S. Environmental Protection Agency, Research
Triangle Park, NC, September 1981.
2. Procedures for Emission Inventory Preparation - Volume III; Area Sources,
EPA-450/4-81-026C, U.S. Environmental Protection Agency, Research
Triangle Park, NC, September 1981.
3. Procedures for Emission Inventory Preparation - Volume IV: Mobile
Sources, EPA-450/4-81-026d, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1981.
4. Procedures for Emission Inventory Preparation - Volume V; Bibliography,
EPA-450/4-81-026e, U.S. Environmental Protection Agency, Research
Triangle Park, NC, September 1981.
5. AEROS Manual Series, Volume II, AEROS User's Manual, EPA-450/2-76-029,
U.S. Environmental Protection Agency, Research Triangle Park, NC,
September 1980 (Update No. 3).
6. 1977 National Emissions Report, EPA-450/4-80-005, U.S. Environmental
Protection Agency, Research Triangle Park, NC, March 1980.
7. The Emission Inventory System/Point Source User's Guide, EPA-450/4-80-010,
U.S. Environmental Protection Agency, Research Triangle Park, NC, May
1980.
8. The Emission Inventory System/Area Source User's Guide, EPA-450/4-80-009,
U.S. Environmental Protection Agency, Research Triangle Park, NC, May
1980.
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9. Procedures for the Preparation of Emission Inventories for Volatile
Organic Compounds, Volume I, Second Edition, EPA-450/2-77-028, U.S.
Environmental Protection Agency, Research Triangle Park, NC, September
1980.
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2.0 MANAGEMENT AND PLANNING OF THE EMISSION INVENTORY PROGRAM
The air pollution emission inventory provides the technical foundation
for all agency programs designed to improve or maintain ambient air quality
within its jurisdiction. An accurate, comprehensive, and current record of
all sources of air pollutants and their emissions is essential for the
assessment of existing air quality and the development of future control
19
strategies-J-'^
The maintenance of the emission inventory is a dynamic process,
reflecting technical improvements in inventorying methods and procedures and
the changing patterns of emissions within a region. Periodic updates, in
addition to providing a current data base, can further improve the accuracy
and usefulness of the inventory as:
(1) additional information is added to improve the spatial and temporal
resolution of the Inventory;
(2) new technology is used to identify additional sources, develop and
improve emission factors, and provide better definition of emissions
with regard to speciation (e.g., compound identification of VOC
emissions or the fine particulate fraction of total particulate
emissions) and new pollutant identification (e.g., hazardous
pollutants);
(3) data management systems are upgraded to improve data handling,
analysis, validation and reporting; and
(4) errors are eliminated and confidence in the reliability of the
inventory improved through documentation, quality assurance, and
ultimately the demonstrated utility of the Inventory for assessing
control strategies and air ruality.
Agency management is charged with the responsibility of developing,
maintaining, and upgrading the inventory. To effectively carry out this
mandate, management must:
(1) Understand and appreciate the uses and significance of the inventory
as applied to existing and future agency programs (as a corollary,
management must also understand the limitations of the existing
inventory and the benefits to be realized from activities aimed at
reducing these limitations);
(2) Understand the managerial and technical requirements involved in
emission inventorying activities which require:
(a) Interfacing of personnel and support facilities within the
agency to provide the full range of necessary skills;
(b) Identifying all methods and procedures used in inventorying;
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(c) Training of personnel In the use of the above techniques;
(d) Utilizing, to the extent possible, technical support within and
outside the agency to upgrade the inventory process; e.g., by
updating emission factors, utilizing available computer
programs, or identifying useful data bases available within the
agency or from other Federal, state and local agencies;
(e) Documenting inventorying activities and using quality assurance
procedures to eliminate errors from the data base and assess
the quality of the inventory; and
(3) Utilize (1) and (2) above to effectively plan and conduct inventory
activities within a schedule consistent with the immediate and the
overall needs of the agency.
The uses and applications of the emission inventory are described in detail in
Chapter 3. Specific limitations of the inventory and corrective procedures
are discussed in detail in Volumes II, III, + and IV-* which discuss
inventorying methods and procedures for point, area, and mobile sources,
respectively. The following subsections within this Chapter will address the
managerial and technical requirements of inventorying activities and the
planning and scheduling of such activities by agency management.
2.1 EMISSION INVENTORY PROGRAM ORGANIZATIONAL STRUCTURE
Management must have a thorough knowledge of the organizational structure
of the air quality agency and the areas of responsibility of each department
or branch within the agency. This knowledge is necessary because emission
inventory activities, in most agencies, are carried out by emission inventory
program personnel drawn from several branches of the agency. Management must
establish priorities, vis-a-vis other branch and interbranch activities,
assemble an emission inventory projtct team, and establish and maintain a
project plan, including schedule, consistent with the priorities and magnitude
of the inventorying effort.
2.1.1 AGENCY ORGANIZATIONAL STRUCTURE
Typically, local and state agencies are divided into various areas of
responsibility." The specific organizational structure will vary from
agency to agency, and may not be identical to that presented in Figure 2-1.
However, the following discussion of branch functions is relevant to all
agencies, regardless of their individual organizational structure.
The Engineering Branch handles source-related functions that Involve
process, control system, and emission analyses. The results of such
activities provide primary inputs to agency actions such as the issuing of
construction, operating, emissions offsets, and prevention of significant
deterioration permits; new source reviews; environmental impact reviews;
emission inventory operations; and any special studies such as energy
analysis. While engineers in this group operate primarily in the central
agency office, they make field visits as required.
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The Transportation and Planning Branch is involved with all mobile source
and planning activities. In addition to their involvement with the automobile
inspection and maintenance program, this branch is responsible for the
development of new regulations, implementation plan reviews, and control
strategy development for mobile sources. This branch also prepares all land
use density maps and similar aids used in highway maintenance planning.
Overall, their function is analysis related.
The Technical Services Branch provides support through laboratory
analysis and quality control operations. Laboratory activities conducted in
support of ambient monitoring and stack testing, oil or hazardous waste sample
analysis and quality assurance and quality control programs, such as equipment
calibration and laboratory performance audits, are the responsibility of this
branch.
Engineers and inspectors working in the Enforcement and Compliance Branch
are responsible for source activities related to compliance, as well as for
the operation of ambient monitoring stations. All compliance, NSPS, and
NESHAPS inspections, as well as source, testing and routine source surveillance
programs, are conducted by this branch. The investigation of special
problems, such as events involving chemical spills and hazardous waste sites,
is carried out by the Enforcement Branch which concentrates on field
activities.
Typically, there is substantial ongoing interbranch activity.
Engineering and Planning Branches often rely on data obtained by the
Enforcement Branch. This branch, in turn, relies on laboratory support for
technical services, and all branches utilize support services such as data
processing. Few agency activities are totally the jurisdiction of one
branch. Due to this interbranch coordination, the formation and operation of
an emission inventory task force will not require substantial, if any, changes
in the typical operational mode of the agency.
2.1.2 EMISSION INVENTORY TASK FORCE ORGANIZATIONAL STRUCTURE
Most agencies, as a result of ongoing inventorying efforts, will have in
place a structure consisting of personnel charged with the responsibility of
maintaining the emission inventory data file and with conducting additional
inventorying activities as required by the agency. The existence of an
emission inventory activity and structure within an agency provides the
foundation for any additional emission inventory activity deemed necessary by
the agency.
All emission inventory activity should be undertaken under the direction
of an emission inventory program coordinator. The coordinator, typically a
member of the Engineering Branch, will be responsible for the day-to-day
inventorying activities, transforming management directives and guidelines
into specific tasks and actions. The coordinator will also play an active
role in defining the short and long term goals of the emission inventory
process consistent with the needs of the agency. Program plans relating to
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maintaining and upgrading the inventory and for conducting specific
assignments to assist the agency in its assessment of control strategies will
be prepared by the coordinator in conjunction with management. These plans,
whether defining long range goals or short term objectives of specific
emission inventory activities, should define manpower requirements and
schedules and fully document in writing the objectives and procedures of the
inventorying activity.
All personnel who will be involved in emission inventory activities such
as data collection and processing should be made aware of the reason for their
involvement and be able to relate their activities to those of other members
of the project team and to the needs of the agency. Certain short term
objectives of the inventory will also set specific data requirements. For
example, an agency as part of its ongoing emission inventory may elect to
include in its point source file all dry cleaning sources or all sources of
lead. In such specific inventory activities the number of pollutants to be
surveyed, their level of temporal and spatial resolution, and industrial and
source descriptions are data established by the specific requirement for the
inventory.
Management must decide the most cost-effective means of obtaining and
processing the required data for the maximum number of sources. Management
may choose to use a questionnaire in order to contact sources rather than
actual source visits, or it may decide to survey only selected
"representative" sources, and scale the data to the entire sample population.
Management's selection of a collection method will also be affected by the
availability of automatic data processing (ADP) capability. Large-scale
inventory efforts, involving hundreds of sources, will realistically use
ADP.1»2 Manual techniques, while practical for smaller inventory efforts,
cannot efficiently handle the extensive amount of data collected for a
comprehensive emission inventory. Management must decide the extent of the
inventory in terms of industries and sources to be surveyed, inventory
methods, use of ADP, and overall manpower and resource commitments. The
performance of specific work aspects ot the program should be left to the
coordinator. Questions such as who will log in returns, what to include in a
survey questionnaire, and how and when to recontact sources for data
verification should be the responsibility of the coordinator. This individual
should be best able to handle the day-to-day needs of the project.
An end result of the development of the project plan will be an estimate
of the manpower requirements and schedule.''*** To ensure that the emission
inventory accomplishes all of its objectives, yet minimizes resource
requirements, a manpower utilization plan must be developed. To do so, the
emission inventory program is broken down into its component parts and each
part is allocated a given number of "man-hours." Chapter 7 of this volume
presents a manpower model for a planning effort of this nature, based, in
large measure, on experience and on information presented in References 6
and 7. Personnel assignments will be the responsibility of the project
coordinator, however, management must coordinate personnel assignments with
the various branch chiefs and establish priorities for assignments.
Management is ultimately responsible for ensuring that tasks are completed
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within their allocated time frame, and redirecting resources if a problem
arises in an area that requires more time than initially scheduled.
Management must ensure that some feedback mechanism is incorporated into its
program plan. Feedback mechanisms to quickly identify problems during the
preparation of the inventory and problems associated with the data base and
its use can forstall the development of more serious future difficulties. The
inventory coordinator must monitor the hours spent on every task each week,
and report back to management, weekly or biweekly, on the progress of the
program.
2.2 PLANNING
The basic elements of an emission inventory are (a) planning; (b) data
collection; (c) data analysis and validation; (d) data formatting and
handling, and (e) reporting. Management will be most directly involved with
planning, which in itself Involves all other program elements. Management
must hold itself responsible to initiate, conduct, and direct the completion
of a program plan and the design of a program structure for the continuous
development of the inventory. The progress of the inventory effort should be
monitored continually and actions instituted to redirect the agency's efforts
should changes occur.
2.2.1 GENERAL PLANNING CONSIDERATIONS
Prior to initiating the actual compilation of an inventory of point
source emissions, the agency's management and technical staff must carefully
assess the needs and objectives of the inventory. At the end of the planning
period, and prior to initiating the data collection phase, the agency will
have addressed the items listed below.^
The end use(s) of the inventory are established.
Sources and source categories have been defined which are compatible with
available source and emission information, and are of sufficient detail
to facilitate control strategy projections, excluding nonreactlve
compounds in the case of a volatile organic compound (VOC) emission
inventory.
The role of existing inventory data has been determined and any
previously omitted data and sources have been identified.
The point source cutoff has been defined. Sources smaller than the
cutoff limit will be treated as area sources.
The geographic area has been identified. Typically, this area will
consist of the agency's entire jurisdiction.
Decisions have been made on whether to temporally adjust emissions, also
to what level; seasonally or daily.
The point source data collection methods have been determined.
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Procedures for identifying nonreactive emissions have been selected.
The agency has decided on how emissions will be projected, and the
projection period, including end year and intermediate years, has been
designated.
An inventory data handling system has been selected and coding forms
developed for loading the system..
The agency's future use of dispersion models has been considered and the
appropriate adjustments in inventory plans have been made.
Quality assurance procedures have been selected and a quality assurance
coordinator identified for the program.
Manpower and budget allocations have been made and organization has been
established by assigning authority and responsibilities.
2.2.1.1 End Uses of the Inventory
A basic consideration in planning the inventory is establishing the end
uses of the completed inventory. The end uses of all inventories fall into
two general categories: (1) air quality control strategy development and air
quality maintenance and (2) air quality research. Possible future use of the
inventory as well as immediate objectives should be considered in determining
procedure and data needs.
The Clean Air Act Amendments of 1977 requires the development of emission
inventories, which are far more detailed and comprehensive than previously
specified and those currently available in many control agencies throughout
the country.^
Air quality research inventories fulfill agency's requirements for
studying relationships between emissions and ambient air quality. The agency,
during the conduct of research programs, may collect data which is more
detailed and extensive than that required by legislation. The agency can
elect to include those data in the comprehensive inventory depending upon
future needs and update requirements.
2.2.1.2 Sources of Emissions
An important consideration affecting emission inventory accuracy is
whether the agency has included all point sources and area source categories
in its emission inventory. Volumes 11,3 HI,4 aru} jy^ describe
procedures for identifying individual point, area and mobile source
categories. Additional information concerning source identification can be
found in other EPA reports such as References 8 and 9 which deal with sources
of VOC emissions.
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It Is important that all of the emitting points that may be associated
with individual sources or source categories be identified if an accurate
inventory is to be prepared. For example, a petroleum refinery contains many
emission points ranging from process heaters to Individual seals and pumps.
General process and emission information can be obtained from AP-42.10
Other EPA publications including the Control Technique Guidelines series for
specific VOC source categories,* Industrial Process profiles for environmental
use such as Reference 11, Source Assessment reports such as Reference 12, and
many references contained in Volume V^ Of this series provide source and
emission data that will be useful to agency personnel in preparing a complete
inventory of all sources.
2.2.1.3 Point/Area Source Distinctions
A major distinction typically made in inventories Is between point and
area sources. Point sources are those facilities/plants/activities for which
individual source records are maintained In the inventory. Under ideal
circumstances, all sources would be considered point sources. In practical
applications, only sources that emit more than some specified cutoff level of
pollutant are considered point sources- Depending on the needs of the agency,
this cutoff level will vary. Area sources, In contrast, are those activities
for which aggregated source and emission information are maintained for entire
source categories rather than for each source therein. Sources that are not
treated as point sources must be included as area sources. The cutoff level
distinction is especially important in the VOC inventory because there are
many more small sources of VOC than of most other pollutants.
If too high a cutoff level is chosen, many facilities will not be
considered individually as point sources, and if care is not taken, emissions
from these sources may not be included In the inventory at all. Techniques
are available for "scaling up" the area source Inventory to account for
missing sources amd are presented In References 8 and in Volume III^ of this
emission Inventory series. Area source procedures are invariably less
accurate than point source methods.
If too low a cutoff level is chosen, the result will be a significant
increase (1) in the number of plant contacts of various sorts that must be
made and (2) in the quantity of data that must be compiled and maintained.
While a low cutoff level may Increase the accuracy of the Inventory, the
tradeoff is that many more resources are needed to compile and maintain the
inventory.
A required upper limit on the point source cutoff level is 100 tons/year
and a lower cutoff level is encouraged to account for many source categories
which are identifiable, controllable, and collectively significant. For
*Available from the Director, Emissions Standards and Engineering Division,
Mail Drop 13, U.S. Environmental Protection Agency, Research Triangle Park,
North Carolina 27711.
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example, many VOC sources emitting less than 25 tons per year were identified
in a recent study of VOC emissions from urban industrial sources.^-^
Moreover, many of these sources are in categories for which no reliable area
source inventory procedures currently exist. Because of this, some agencies
have elected to define cutoff levels at or below 5 tons per year in order to
include a large percentage of VOC and other emissions in the point source
inventory.
2.2.1.4 Geographical Area/Spatial Resolution
The geographical area to be inventoried is defined herein as that area
which falls within the jurisdiction of the state agency conducting the
inventory. Emission points within this area must be precisely located.
Dispersion modeling studies sometimes require that point sources be determined
to within 10 meters. Although existing sources contained in NEDS are only
specified to 100 meters, a resolution of 10 meters Is recommended whenever
possible. Two grid systems have been developed for locating geographical
points: (1) latitude and longitude and (2) universal transverse mercaptor
(UTM). Advantages of the UTM grid system include the following.
1. Grids are continuous and are not hindered by political subdivisions.
2. UTM grids are uniform.
3. The UTM system Is used worldwide.
4. The UTM system Is associated with a growing body of technical
information.
2.2.1.5 Temporal Resolution
Emission data for a calendar year have historically been collected by
most agencies, mainly because activity levels are most readily available on an
annual basis. In some cases the agency may need to adjust annual emissions
rates to a seasonal, daily or hourly basis. Certain source categories operate
only during certain hours of the day or during certain seasons of the year;
e.g., many sand and gravel operations. Activity levels and corresponding
emissions from other categories (e.g., mobile sources, surface coating,
pesticide application and small boiler operations) are strongly temporal
dependent. Other categories such as solvent storage are also
temperature-dependent." Temporal variations In emission rates, because of
their Influence on ambient pollutant levels, must be considered by the agency
in defining the data requirements of the Inventory.
2.2.1.6 Data Collection Methods
Methods for collecting data for point, area and mobile sources of
emissions are presented in Volumes II, III, and IV, respectively.3>4,5
However, the Inventorying agency must decide which procedures to use in its
inventory effort. Point source methods include mail surveys, plant
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inspections, and use of agency permit and compliance files. Area and mobile
source methods are usually dependent upon correlative relationships among
statistical parameters and activity levels/emissions. The agency should
determine in the planning phase what methods and reference sources will be
used in data collection. Early definition will allow time to obtain necessary
reference and support materials and will help to better allocate work hours to
the individual data collection tasks as well. Data collection methods and
considerations for their use are discussed in greater depth in Chapter 5.
2.2.1.7 Special Procedures
Special procedures may be required to obtain information not normally
obtained when compiling an emission inventory. This information may be
temporal data or relate to pollutant characterization; e.g., fraction of
inhalable particulate or organic compound identification . While most
volatile organic compounds ultimately engage in photochemical reactions, some
are considered nonreactive under atmospheric conditions. Therefore, controls
on the emissions of these nonreactive compounds do not contribute to the
attainment and maintenance of the National Ambient Air Quality Standard for
ozone. These nonreactive compounds are listed below:
Methane
Ethane
1,1,1-Trichloroethane (methyl chloroform)
Methylene chloride
Trichlorofluoromethane (CFC 11)
Dichlorodifluoromethane (CFC 12)
Chlorodifluoromethane (CFC 22)
Trifluoromethane (FC 23)
Trichlorotrifluoroethane (CFC 113)
Dichlorotetrafluoroethane (CFC 114)
Chloropentafluoroethane (CFC 115)
The above compounds should be excluded from emission inventories used for
ozone control strategy purposes. References 8 and 9 should be referred to for
more detailed information on excluding nonreactive VOC from emission totals.
Because the above list may change as additional information becomes available,
the inventory agency should remain aware of EPA policy on reactivity.
Even though data are not needed in the basic inventory, the agency may
find it expedient to collect this information when plant contacts and surveys
are made as part of a routine update of the inventory. If an agency
anticipates the need for special data, it is more efficient to collect the
data at the same time the other source and emission data are collected for the
basic inventory.
2.2.1.8 Emission Projections
During the planning stage of the emission inventory, it is necessary to
identify the type of emission projection procedures that will be used. The
two types of emission projection procedures are baseline and control
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strategy. The agency will need to evaluate its current emission control
strategy and determine the likelihood of the promulgation of additional
control measures which would affect emissions during the projection years. If
it appears that there will be limited changes in the control strategy, then
the agency should plan to employ the baseline projection procedure. However,
if it appears that new regulations will be enacted which will affect
emissions, then the agency should employ the control strategy projection
procedure.
2.2.1.9 Status of Existing Inventory
A major inventory planning consideration is whether or not and to what
extent information contained in an existing inventory can be utilized. The
existing inventory should be examined to see if the appropriate sources have
been included and that the emission data are representative of current
conditions- Existing inventories serve as a starting point for developing a
mailing list for questionnaire distribution and should provide extensive data
and support information, such as documentation of procedures.
2.2.1.10 Data Handling
Data handling and retrieval can be done by computer or manually.
Combinations of these methods are also possible. The selection of one
approach over the other will depend on several factors:
Availability of a computer,
Size of the inventory data base,
Complexity of the emission calculations,
Number of calculations to be made,
Variety of tabular summaries to be generated,
Availability of clerical and data handling personnel, and
Time constraints.
Computer data handling becomes significantly more cost effective as the data
base, the variety of tabular summaries, or the number of iterative tasks
increases. In these cases, the computerized inventory requires less time and
has the added advantage of forcing organization, consistency, and accuracy.
Some of the activities which can be performed efficiently and rapidly by
computer include:
Printing mailing lists and labels;
Maintaining status reports and logs;
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Calculating and summarizing emissions;
Performing error checks and other QA functions;
Storing source, emission, and other data;
Sorting and selective accessing of data; and
Generating output reports.
During the planning stages, an agency should anticipate the volume and
types of data handling needed in the inventory effort, and should weigh
relative advantages of manual and computerized systems. If an agency must
deal with large amounts of data, a computerized inventory data handling system
allows the agency to spend more time gathering, analyzing and validating the
inventory data as opposed to merely manipulating it. The computerized
approach is superior for large areas having a diversity of sources comprising
a complex inventory.
If the agency anticipates use of a photochemical dispersion model at some
future date, it is Imperative that a computerized data handling system be
utilized. The added complexity Involved in developing spatially and
temporally resolved estimates of several VOC classes from the basic inventory
represents too much work to complete manually. Data handling requirements for
inventories used in photochemical models are discussed in References 2 and 8.
2.2.1.11 Quality Assurance
Quality assurance is important in achieving user confidence in an
emission inventory. A quality assured inventory will result in a more
accurate inventory and lead to better assessment of control strategies and the
Impact of emissions on air quality. Also, lower program costs may be realized
because inventory updates and revisions will not be as extensive as when
conducted without a quality assurance program.
A quality assurance program applied to an emission Inventory, contains
three general types of procedures. Standard operating procedures includes
organization planning, personnel training, project planning, and the
development of step-by-step procedures for technical tasks. Techniques for
finding and correcting Inconsistencies and errors includes identification of
potential error sources, evaluation of the impact of these sources, location
of checkpoints for optimal problem detection, and a provision for timely
response when problems occur. The determination of product quality and
reliability, in the context of an emission inventory, Is the same as data
quality assessment. These procedures Include a periodic review of the entire
inventory process, the development of standards against which to test the
accuracy and precision of results, and a system evaluation to maintain optimal
resource efficiency.
Standard operating procedures must be outlined as the inventory effort is
planned. Identifying and correcting Inconsistencies and errors In the
inventory can also be anticipated in the planning phase. The quality
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assurance program Is designed to minimize the following potential sources of
error.8
Missing facilities or sources—Permit and inventory systems out of phase;
errors in estimating potential emissions; lost paperwork; problems with
computer file updates.
Duplicate facilities or sources—Name changes through corporate
acquisitions; use of multiple data sources with different source
numbering schemes.
Missing operating or technical data—Ambiguous data request forms;
intentional deletion by facility staff; Inadequate followup procedures;
no preliminary indication of inventory size; or overall inadequate
project control.
Erroneous technical data—Misinterpretation of data request instructions;
assumed units, faulty conversions, etc.; Intentional misrepresentation by
the facility; poor handwriting.
Improper facility location data—Recording coordinates of facility
headquarters Instead of the operating facility; inability of technicians
to read maps; failure to observe inventory area boundaries.
Inconsistent area source categories or point source sizes—Failure to
designate inventory cutoffs.
Inaccurate or outdated data—Mixed use of primary and secondary data
without a policy for standardizing data.
Errors in calculations—Transposition of digits; decimal errors; entering
wrong numbers on a calculator; misinterpreting emission factor
applications.
Errors in emission estimates—Imprecise emission factors; applying the
wrong emission factor; errors In throughput estimates; improper
interpretation of combined sources; errors in unit conversions; faulty
assumptions about control device efficiency; failure to exclude
nonreactlve emissions.
Reported emissions wrong by orders of magnitude—Recording the wrong
identification code for subsequent computer emission calculations;
Ignoring implied decimals on computer coding sheets; transposition
errors; data coding field adjustment.
The determination of product quality requires the development of
procedures to measure the completeness and accuracy of the data file. If a
computer data handling system is available, a computer program can perform
checks for implausible entries, missing data, and conformity of calculated
results with known data relationships. Manual spot checks on the point source
records can be performed when computers are not available.
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Principles of quality assurance can be applied in planning, data
collection, calculations, and reporting of the emission inventory. Quality
assurance requires anticipating the measures needed in each of the inventory
functions. To promote effective quality assurance, the inventory planner
should consider the steps listed below prior to initiating inventory tasks.^
1. Planning
- Plan to allocate resources for maximum quality assurance.
- Plan to account for significant emission sources.
- Prepare a checklist of sources to be evaluated.
- Use staff experienced in data collection and analysis.
Plan for routine checking of calculations.
Plan for checking data file entries.
- Prepare data checking programs (when using a computer for data
handling).
- Maintain a separate quality assurance staff.
2. Data collection and analysis
- Use redundant identification of major sources (quality
assurance staff should prepare an independent source list).
- Check questionnaire design.
- Check data collected.
- Check emission estimation methods.
- Check calculated results.
- Verify adherence to quality assurance procedures.
3. Data handling
- Check data file entries.
- Check individual data entries (missing emissions, SIC codes,
addresses, etc.)
- Assign agency estimates for missing data.
- Check for data correctness.
Review tabulated data for quality.
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4. Data reporting
Check the aggregation of emissions.
- Compare results with those of other Inventories.
- Check disaggregation of emissions (if allocated to subcouniy
areas).
The above is Intended to acquaint the user with the concepts and principles of
quality assurance. Before planning a quality assurance program, additional
information on these concepts and principles must be obtained. Such
information on emission inventory quality assurance can be found in References
15 through 17 or can be obtained through an EPA Regional Office. The most
effective instruments of quality assurance are the standard operating
procedures developed by the agency as these steps determine methods to be used
throughout the inventory effort.
2.2.1.12 Documentation
Documentation is an integral part of an emission inventory. Review of
the written documentation of an Inventory's data sources and procedures by the
agency's quality assurance and technical personnel will uncover errors In
assumptions, calculations or methods. Remedial actions to correct detected
errors will lead to the development of a reliable and technically defensible
data base which is essential in enforcement actions, source impact
assessments, and development of emission control strategies.
While documentation requirements may evolve during the data collection,
calculation, and reporting steps of the emission Inventory, these requirements
should be anticipated during planning. Planning the level of documentation
required will (1) ensure that importnr.t supporting information Is properly
developed and maintained, (2) allow extraneous information to be identified
and disposed of, thereby reducing the paperwork burden, (3) help determine
data storage requirements, and (4) aid in identifying aspects of the inventory
on which to concentrate quality assurance efforts."
2.2.1.13 Emission Inventory Manpower Requirements
To ensure that sufficient resources have been allocated to achieve good
results with an inventory effort, cost and manpower requirements should be
evaluated in the planning stage of the project. Technical manpower and budget
allocations required will be a function of the number and type of sources to
be inventoried, the pollutants being inventoried, and the desired data base
detail. These Inputs, in turn, will be affected by the inventory end use and
by the data handling capabilities. Administrative and secretarial support
will be a function of the technical manpower and budget allocations determined
by all of these factors.^>^
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Since cost and manpower requirements will vary for each inventory effort,
manpower and budget allocations must be determined. When an agency has
conducted inventories regularly, its past experience can be used to estimate
requirements- A computer model is also available from EPA which estimates
technical and administrative costs associated with emission inventories.^
Information is obtained through EPA Regional Offices or from the Control
Programs Operations Branch, Control Programs Development Division, MD-15, U.S.
Environmental Protection Agency, Research Triangle Park, NC 27711.
2.2.2 SPECIFIC PROCEDURES
Planning includes a variey of procedures that reflect agency goals and,
as a consequence, require management decisions. These decisions address
definitional, organizational, and technical problems.16
The definitional phase of the planning step is the one in which
management defines the system objectives and outlines the basis for meeting
those objectives.
1. Define objectives—This procedure requires management to assess the
short term and long term goals of the emission inventory program-
The purpose of the emission inventory program is to maintain a
current and reliable data base which is used to support agency
programs for attaining and maintaining air quality. However,
specific programs, for example to assess trends in emissions, can be
conducted to satisfy specific immediate objectives as well as
satisfying the general purpose of the inventory.
2. Define requirements for meeting objectives—Once the major goals of
the emission inventory process have been identified, management,
with assistance from the technical staff needs to define the types
of information required and to take steps to obtain that
information. The steps include defining specific data requirements
and formats, establishing the authority to obtain and verify the
necessary emission data, and defining data quality goals.
The organizational procedures are those that determine the total effort,
the resources that will be expended, and the relationship between the
inventory process and other agency functions. Procedures must be established
that accomplish the following.
1. Relate program and agency functions—This procedure includes an
organizational audit to define the purpose of each branch and
subgroup within the agency and the level of support that they can
and will provide.
2. Assign responsibilities—This establishes the responsibilities and
authority of the branch or group for compiling and maintaining
emission inventory data. It is an early step in developing a
mechanism for establishing the emission inventory. It might also
include, for example, an assessment of the degrees of support that
branch office operations can provide.
2-16
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3. Establish communications—This determines the flow of Information
between management and the subdivisions of the agency. It also
establishes the environment for interdepartmental transfer of
technical data and support of the inventory and its programs-
4. Assign priorities—This function follows from the assessment by the
agency of the scope of its air pollution problems, and the need for
the inventory program based on existing air quality and the degree
of industrialization or urbanization of the area within its
jurisdiction.
5. Budget resources—This function Is the logical extention of the
assignment of priorities. Budget decisions reflect the expected
impact of the emission Inventory on agency effectiveness, and they
affect the types of inventory procedures that will be adopted.
6. Document procedures—This function is the formal summary of the
activities mentioned above.
The technical procedures help to establish the degree of confidence that
can be placed in the emission inventory results. They affect the precision
and accuracy of the inventory, and the degree to which results can be compared
within or among agencies. These procedures are:
1. Develop inventory techniques—This includes decisions about the
emission factors to be used, techniques to Identify sources, data
gathering techniques, manual versus computer data processing,
quality assurance programs, and workflow procedures within the
organization. These are some examples of a range of complex
functions encountered in inventory programs.
2. Develop job descriptions—This includes writing job descriptions for
personnel who will be assigned exclusively to the emission inventory
process. A written job description will identify skills required to
perform the activity; the experience and performance level of
personnel; arid the training requirements.
3. Identify training requirements—This includes an evaluation of the
technical questions that must be addressed in compiling an emission
inventory, and the functions requiring special skills or periodic
updating of techniques. The training programs and schedules will be
designed to aid In incorporating improved inventory techniques and
to improve performance of inventory functions.
The end result of planning activity will be a documented program with specific
objectives and established priorities for achieving the objectives within a
defined time frame and budget. A reasonable program plan relies heavily on
input from the definitional phase of task planning; I.e., management
objectives, inventory quality goals, etc.
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2.2.3 PROJECT SCHEDULES
The Time Requirement Model (TREM) discussed in Chapter 7 allows the
manager of an emission inventory to estimate the amount of time required to
perform various activities. However, knowledge of the tasks and their
estimated time requirements alone is insufficient to conduct the inventory
efficiently, or properly allocate the resources available. Modern project
management techniques should be utilized to plan, control, and schedule the
numerous activities into a cohesive course of action.
The development and maintenance of an emission inventory can be
conceptualized as a network of activities that can be mapped out on a chart.
The various inventory tasks are defined as individual activities with a
definite start and end. The initiation and completion of an activity are
denoted by the term "event." Techniques to formulate a project schedule for
tasks and events are then utilized.
Program evaluation and review techniques (PERT),* Barcharts (BACH,)*
and Critical Path Method (CPM)* are relatively simple methods that are
available to identify critical activities and evaluate costs and technical
progress. The identification of specific tasks and the logical sequence of
activities and their interrelationships within the overall program are useful
to both management and the task team in performing the various necessary
functions and identifying problem areas and viable alternative plans and
schedules.
The scheduling techniques subsection, below, discusses some of the
available methods to efficiently organize a project such as an emission
inventory. In particular, PERT and CPM are discussed. The task sequences
subsection demonstrates briefly how various inventory tasks are scheduled in a
progression. Finally, the task schedule subsection shows how the PERT or CPM
evaluation methods can be used to determine where "critical sequences" are
likely to occur in a series of events.
2.2.3.1 Scheduling Techniques
Standardized techniques used for program scheduling and monitoring
include PERT, CPM, and variations. These techniques are fundamentally simple,
and this fact heightens their utility. The network or bar chart analysis
yields the following advantages for both management and agency personnel:
*Further details concerning PERT, BACH, CPM and their variations can be
found in References 19 through 24.
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For management,
1. More realistic time cost estimates,
2. Improved program control through early detection of uncompleted
events, and
3. Good simulation and projection of alternative plans and schedules;
For agency personnel,
1. A better visualization of the individual tasks,
2. Relevant and meaningful interim schedule objectives,
3. Improved communication among agency personnel, and
4. More distinct delineation of task and decision responsibilities.
For the purposes of PERT and CPM techniques, all objectives and goals
should be defined. Each activity has definite start and end points that are
termed "events" or "nodes." An event has no time duration and serves to
indicate the start or completion of an activity. The activities are the links
connecting the events, and these have measurable performance times.
Three basic steps are required for PERT or CPM analysis:
1. Develop the network of events from time of start to the completion
of the inventory.
2. Estimate the time required to accomplish each activity in the
network, using past experience of the manpower/resource allocation
model in Chapter 7.
3. Perform analyses of possible schedule problems through the
determination of the longest or "critical path" in the network of
events.
The PERT and CPM techniques are not meant to perform decision analysis
for the manager, but rather allow the manager to develop and order a plan of
activities, and to determine the critical aspects of program performance. In
anticipating problems and possible delays, the manager is able to formulate
effective corrective actions. Viewing the entire project on a network diagram
provides a greater understanding of the coordination of activities.
2.2.3.2 Task Sequence
In the formulation of a project schedule, it is necessary to establish
the sequence of activities and events using a chronological order to ensure
the elimination of conflicts. An understanding of the rational progression
of events is necessary for establishing the network of events required to
achieve the desired objectives.
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The basic sequences of activities for point, area, and mobile source
inventories are:
1. For point source inventories:
a. Identification of inventory data needs;
b. Establishment of data collection and handling methods;
c. Development of a source listing;
d. Development of questionnaires;
e. Collection and compilation of data, including printing the
mailing list and labels, mailing questionnaires, logging and
reviewing returns, and questionnaire followup to obtain
complete and reliable information.
f. Assistance to questionnaire respondents;
g. Transfer of data to the data handling system;
h. Calculation of emissions;
i. Quality assurance; and
j. Presentation of results.
2. For area and mobile source inventories:
a. Identification of inventory data needs for estimating activity
levels and emissions,
b. Establishment of data collection and handling methods,
c. Data collection and compilation,
d. Apportionment of data to desired geographical and temporal
levels,
e. Calculation of emissions,
f. Transfer of data to the data handling system,
g. Quality assurance, and
h. Presentation of results.
The listings of sequential activities presented above are by no means
complete. Additional intermediate steps can be included for better resolution
of manpower requirements and schedule. However, by Inspection of the above
listings, the basic sequence of activities Is:
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1. Identification of data needs,
2- Establishment of methods,
3. Collection of data,
4. Analysis and compilation of data, and
5. Presentation of results.
2.2.3.3 Task Schedules
The use of PERT and CPM is suggested in order to determine the
critical sequence of operating and other specific steps most likely to cause
delays, and to aid in determining the shortest path (or least time, cost,
etc.) to achieve completion of the project. A key feature of these techniques
is the use of "milestones" to delineate significant points of development in
the inventory process. These milestones include:
1. Initiation of a specific activity,
2. Completion of the activity,
3. Scheduled events (i.e., meetings), and
4. Submission of interim, progress, and final reports. (Typically,
these will be oral reports to management and agency groups not
directly responsible for the inventory.)
These milestones enable the manager to monitor the progress of each task,
and provide the opportunity to adjust or reschedule events in accordance with
the milestones. As a project progresses, some changes in activities will
occur and new milestones may be designated.
Using the TREM to estimate the number of hours required, values can be
assigned to activities between specified events and/or milestones. Two
techniques are available for the determination of the "critical path" or
longest time required to complete all the scheduled activities. These are the
deterministic and the probabilistic approaches. The deterministic approach
relies on only one estimate for each activity, and the analysis is then
performed. This estimate should be performed by personnel thoroughly familiar
with the task. The critical path procedures are then applied to find the
longest path through the network. The total time required to complete all
project activities is governed by the critical path (i.e., the longest time
path linking the initial event and the terminal event of a project)•
Probabilistic network scheduling requires three time estimates for each
activity: optimistic time, pessimistic time, and most likely time. This
approach recognizes the uncertainties involved in any project and, in the most
pessimistic case, considers the fact that delays in other agency programs may
affect the emission inventory development schedule.
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Figure 2-2 shows a portion of a network of events A through E and the
estimated relative time requirements (in parentheses) of activities 1 through
7. In order to proceed from event A to event E, the various activities will
have to be performed. The minimum amount of time required to go from node A
to node E can be determined by examining the times required to complete the
activities. As an example, in order to proceed from A to D, activity 3 or
activities 2 and 6 will have to be performed. The maximum time to complete
the AD path is the maximum time required for activity 3 or activities 2 and
6. In this case, the completion of event D is dependent on activities 2 and
6. This process can be expanded to cover the AE pathways, and a critical path
determined.
The probabilistic network schedule utilizes three time estimates:
1. Optimistic time (a). The best or shortest time required to complete
an activity is estimated.
2. Pessimistic time (b). The longest time that an activity should take
is estimated.
3. Most likely time (m). The time estimate which, in the estimator's
judgment, has the probability of greatest occurrence.
EVENTS5 A THROUGH E
ACTIVITIES' I THROUGH 7
RELATIVE TIME REQUIREMENTS: (IN PARENTHESES)
Figure 2-2. Example of a portion of a network.
2-22
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A single average estimate expression of the expected time to complete an
activity is given by:
a + 4m + b
e 6
/ \2
with a , a variance in :
V o I a
The expected time, te, is a statistical expression with time variance
as a measure of confidence of the te value. If the variance is small, then
the confidence in te is high; if the variance is large, then the confidence
in te is low.
The expected time, te, should not be used to actually schedule an
activity. However, It can be used to compare with a scheduled value and
determine the probability of meeting the scheduled time. This allows the
manager to decide the probability of completing a task in a given time within
some confidence limits.
Use of the deterministic and probabilistic time estimates in establishing
critical paths allows the project manager to schedule or reassign activities
as the project progresses. In this manner, optimum use can be made of limited
resources. In addition, information derived from CPM/PERT analysis enables
the project manager to reassess the feasibility of undertaking a given project
task.
2.2.3.4 Example of Project Scheduling
After air quality agency manager^ut has decided upon a task sequence and
schedule for its inventory effort, this schedule and list of activities should
be summarized. Such a summary will not only serve to Inform all program
personnel of the project schedule of activities, but can also be used to track
the progress of the emission inventory program. The most common method of
displaying this summary is a graphical task schedule chart. Figures 2-3 and
2-4 present typical program schedule charts. This type of display clearly and
concisely summarizes the inventory tasks, their scheduled start and completion
dates, and major milestones that must be met. Some charts, such as that shown
in Figure 2-3, may also include project manpower and cost data as well.
The project schedule chart Is completed before the project is begun. It
is based on time and manpower estimates and represents management's best
estimate of an achievable and viable schedule. Once work on the inventory has
begun, actual progress should be tracked, recorded, and revised as needed.
The project schedule chart can also be used for this purpose. Monthly updates
on work progress can be superimposed on the original program schedule to
reflect actual work progress. Figure 2-4 demonstrates how this updating
2-23
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technique has been used on a nonemission inventory program schedule.
Maintaining a program schedule in this manner provides an excellent historical
record of the total work effort. In the short term, It acts as a constant
feedback mechanism to program managers who must monitor the progress of the
project. In this manner, It ensures that no one task will be allowed to drag
on and affect the entire schedule. In the long term, this updated schedule
chart can be used to highlight the shortcomings or successes of the original
platming effort. Problem areas can then be more carefully researched to
ensure that the experience gained will be applied to future projects.
A graphic display of the program schedule is useful in that it outlines
the critical and time-intensive tasks and milestones in the emission inventory
process that should be closely monitored. A comprehensive quality assurance
(QA) program must be developed to ensure use of consistent data gathering,
handling, and analysis procedures thus helping to assure an error-free data
base. Since each specific inventory task Is listed on this display, a quality
assurance coordinator can plan his overview checks and Inspections to
correspond to the task schedule. The frequency of quality assurance
inspections can be geared to the scheduled time of each task, with more checks
made on the time-intensive tasks. Milestones can be used as quality assurance
triggering devices In this regard. When the program display indicates an
upcoming milestone for a task, the quality assurance coordinator can increase
his surveillance in that area-
A quality assurace program applied to emission inventory project
scheduling would have three general types of procedures. Standard operating
procedures would include organization planning, personnel training, project
planning, and the development of step-by-step procedures for technical tasks.
Techniques for finding and correcting inconsistencies and errors would include
identification of potential error sources, evaluation of the impact of these
sources, location of checkpoints for optimal problem detection, and a
provision for timely response when problems occur. The determination of
product quality and reliability, In the context of an emission inventory, is
the same as data quality assessment. These procedures include a periodic
review of the entire inventory process, the development of standards against
which to test the accuracy and precision of results, and a system evaluation
to maintain optimal resource efficiency.
In summary, to ensure that agency manpower Is efficiently used In the
compilation of an emission Inventory, a project schedule should be developed.
This schedule should be based on known project tasks and estimated manpower
requirements. A graphical presentation of the inventory tasks, their
estimated completion times, major project milestones, and manpower
reqviirements is a useful way of displaying and summarizing the project
schedule. As the project is carried out, this graph can be revised, and
actual time requirements and completed milestones superimposed on the original
projections. By continually tracking the progress of the overall emission
inventory effort in this way, management can (1) ensure that each task is
being expeditiously carried out, (2) revise Its manpower commitments to
reflect schedule changes, and (3) learn from its experience so that It can
apply this knowledge in future Inventory efforts.
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References for Chapter 2.0
1. Southerland, J., "Emission Inventories: A Perspective," Presented at the
71st Annual Meeting of the Air Pollution Control Association, Houston,
TX, June 25-30, 1978.
2. "Report on Source/Emission Inventory Systems and Data Bases for the
Standing Air Monitoring Work Group," (Unpublished), U.S. Environmental
Protection Agency, Research Triangle Park, NC, 1978.
3. Procedures for Emission Inventory Preparation - Volume II; Point
Sources, EPA-450/4-81-026c, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1981.
4. Procedures for Emission Inventory Preparation - Volume III: Area
Sources, EPA-450/4-81-026c, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1981.
5. Procedures for Emission Inventory Preparation - Volume IV; Mobile
Sources, EPA-450/4-81-026d, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1980.
6. Manpower Planning Model, EPA-450/3-75-034, U.S. Environmental Protection
Agency, Research Triangle Park, NC, 1975.
7. Walsh, G. N. and D. J. VonLehmden, "Estimating Manpower Needs of Air
Pollution Control Agencies," presented at 63rd Annual Meeting of the Air
Pollution Control Association, Paper No. 70-92, 1970.
8. Procedures for the Preparation of Emission Inventories for Volatile
Organic Compounds, Volume I, Second Edition, EPA-450/2-77-028, U.S.
Environmental Protection Agency, Research Triangle Park, NC, September
1980.
9. Final Emission Inventory Requirements for 1982 Ozone State Implementation
Plans, EPA-450/4-80-016, U.S. Environmental Protection Agency, Research
Triangle Park, NC, December 1980.
10. Compilation of Air Pollution Emission Factors, Third Edition and
Supplements, AP-42, U.S. Environmental Protection Agency, Research
Triangle Park, NC, September 1980.
11. Source Assessment: Synthetic Ammonia Production, EPA~600/2-77-107m, U.S.
Environmental Protection Agency, Research Triangle Park, NC, November
1977.
12. Industrial Process Policies for Environmental Use; Chapter 5, Basic
Petrochemicals Industry, EPA-600/2-77-023e, U.S. Environmental Protection
Agency, Research Triangle Park, NC, January 1977.
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13. Procedures for Emission Inventory Preparation - Volume V; Bibliography,
EPA-450/4-81-026e, U.S. Environmental Protection Agency, Research
Triangle Park, NC, September 1981.
14. Shah, M. C- and F. C. Setherman, "A Methodology for Estimating VOC
Emissions from Industrial Sources," Presented at the 71st Annual Meeting,
American Institute of Chemical Engineers, Miami Beach, FL, November 1978.
15. Bradley, R., J. Stredler, and H. Taback, "Improving Emission Inventory
Quality - A QA/QC Approach," Presented at the 73rd Annual meeting of the
Air Pollution Control Association, Montreal, Canada, June 22-27, 1980.
16. Development of an Emission Inventory Quality Assurance Program,
EPA-450/4-79-006, U.S. Environmental Protection Agency, Research Triangle
Park, NC, December 1978.
17. Goklany, I. M., "Emission Inventory Errors for Point Sources and Some
Quality Assurance Aspects," Journal of the Air Pollution Control
Association, 30(4);362-5, April 1980.
18. Donaldson, T., and M. Senan, "Estimating the Cost of State Emission
Inventory Activities," Presented at the 73rd Annual Meeting of the Air
Pollution Control Association, Montreal, Canada, June 22-27, 1980.
19. Moder, Joseph J., and C. R. Phillips, Project Management with CPM and
PERT, Reinhold, New York, 1964.
20. Shaffer, L. R., J. B. Ritter, and W. L. Meyter, The Critical-Path Method,
McGraw Hill, New York, 1965.
21. Kelley, J. E., Jr., "Critical-Path Planning and Scheduling: Mathematical
Basis," Journal of Operations Research Society of America, 9, 1961.
22. Kelley, J. E., Jr., and M. R. foalker, "Critical-Path Planning and
Scheduling," Proceedings of the Eastern Joint Computer Conference, 1959.
23. POD and NASA Guide, PERT Cost Systems Design, Office of the Secretary of
Defense and the National Aeronautics and Space Administration, U.S.
Government Printing Office, Washington, D.C., 1962.
24. Charnes, A., and W. W. Cooper, "A Network Interpretation and a Directed
Subdual Algorithm for Critical-Path Scheduling," Journal of Industrial
Engineering, 13, 1962.
2-28
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3.0 APPLICATIONS AND USERS
3.1 APPLICATIONS OF THE INVENTORY
An accurate, comprehensive and current emission inventory of all sources
can be used for a variety of applications by the air quality control agency.
Proper planning and commitment of resources can help ensure that the emission
inventory includes all the information needed for the specific, localized
needs of the agency.
The specific applications of emission inventory data are many and
diverse. Some are set by federal reporting requirements, while others support
agency programs and services and are responsive to public concerns. As the
compiler of the inventory, and the organization most responsible for its
maintenance, the local agency must design the inventory for its own individual
requirements. Data obtained from each emission source must be processed,
stored and presented in a manner to reflect the priorities of the agency.
All state and local air quality control agencies will have certain common
applications of emission inventory information. In this section, the
principal uses of inventory data will be discussed. These applications will
illustrate how inventory information provides essential input to many air
pollution control programs. The applications will be discussed relative to
activities commonly found in most agencies.
Planning and Development
State Implementation Plan (SIP) preparation and review
- Strategies development
- Modeling
- Reasonable further progress (RFP)
New Source Review
Prevention of significant deterioration (PSD) and emissions
offsets
- Environmental impact review
Surveillance and Analysis
- Ambient monitoring network design
Compliance
Enforcement and compliance
3-1
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Special Studies
Trends
Energy analysis
Research
The applications listed above and discussed below are not intended to be all
inclusive but rather are presented to demonstrate how a well engineered and
prepared inventory can serve as a diversified management tool.
3.1.1 STATE IMPLEMENTATION PLAN (SIP) PREPARATION AND REVIEW
State Implementation Plans (SIPs) are developed by state air quality
control agencies to ensure that the National Ambient Air Quality Standards
(NAAQS) will be met. The plans are required by federal regulation* and
address several distinct activities within an overall air quality management
program. These typically include ambient monitoring, stationary source
emission limitations, compliance schedules, transportation control plans, new
source review procedures, and the establishment of air quality maintenance
areas (AQMAs) among others. Few agencies had detailed emission inventories at
the time the plans were initially prepared in the early 1970's. Consequently,
agency management was forced to develop control regulations for source
categories without a. clear understanding of the actual emisssions from these
categories, or the affect each SIP control strategy would have in reducing
total pollutant concentrations. The initial SIPs therefore had mixed success
in attaining ambient air quality goals. When the Clean Air Act was revised in
1977, Congress recognized the importance of utilizing an emission inventory to
systematically assess and control ambient air pollutant levels. SIP revisions
for areas which had not yet been brought into compliance are required to
provide for the preparation of a detailed emission inventory of that area.**
The reasons for this are clear—to reduce emissions, the sources and
quantities of emissions must be knowr- All sources of emissions, including
the relatively easily identifiable major point sources, broad based area
sources, and the difficult to quantify fugitive emission sources must be
included. Once this comprehensive inventory is established, management can
accurately assess the effect of new regulations.
This use of an emission inventory to evaluate state regulations and SIPs
is as important in attainment areas as it is in nonattainment regions.
Management concern with attainment areas involves ensuring that air quality
will be preserved. Normal growth in business activity will inevitably lead to
a growth in process emissions, and management must plan for this growth and
adjust its regulations accordingly. New regulations promulgated on
*Clean Air Act. Section 110, 40 CFR 51—Requirements for preparation,
adoption, and submittal of implementation plans.
**Clean Air Act, as amended, November 1977. Section 172 (b)(4).
3-2
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this basis can be justified technically and will be more acceptable to the
affected industries and the public in general.
3.1.2 STRATEGIES DEVELOPMENT
Control strategies are adopted to bring noncompliant air quality regions
into compliance and to ensure that regions of compliance retain good air
quality levels. Strategies are typically developed by an agency on a
pollutant-specific basis. The development of any strategy to limit emissions
must use an emission inventory to provide information on the number, location,
and size of emission sources, and one or more dispersion models to relate
emission rates to air quality pollutant levels. Since proposed control
options are frequently expensive to implement, it is important that the
evaluation of various control strategies be based on complete and accurate
emission data.
The various factors that go into development of a control strategy are
presented schematically on Figure 3-1. The emission inventory and control
data identify for management the major sources of emission of a particular
pollutant under investigation. With this knowledge, management can formulate
control strategies which affect one or more source categories and calculate
the change in emissions due to each strategy. For example, one control
strategy to limit sulfur dioxide emissions might only affect emissions from
large, point sources, while a second might concern itself with both point and
area sources. Data on all sources must be included in the inventory to
provide a sound basis for the assessment of a variety of options and
strategies. For each strategy the inventory is adjusted to reflect the effect
of the proposed regulation. Once the effect of each strategy on total source
emissions is ascertained, the resulting change in ambient air concentration
levels must be determined by use of atmospheric simulation models. The agency
ultimately decides which strategy will best accomplish its goals after taking
into account technical, economic and other factors.
To evaluate various control strategies, an agency planner requires
extensive data on the sources emitting a pollutant, including their location,
the pollutant emission rate, the type of emission control, and many other
source, process, and control equipment related parameters. These data will be
available from the inventory in the correct level of detail only if management
has had the foresight to anticipate the need in prior inventory efforts.
Management must recognize the potential utility of the inventory and ensure
that all relevant source data are contained within the inventory.
3.1.3 DISPERSION MODELING
A dispersion model is a mathematical expression that predicts ambient
pollutant levels based on source emission rates and meteorological data.
Models have been used in agency planning efforts to estimate the effect of the
emissions of one source or a group of sources on ambient air quality. As
such, they represent an integral part of such programs as air quality strategy
development, air quality maintenance area planning, new source review
programs, and the prevention of significant deterioration (PSD)
determinations. A number of air quality dispersion and simulation models have
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been developed.^»^ The models differ from each other in a number of ways.
These include the number and type of sources they handle (point, area, line,
etc.). the spatial and temporal resolution of pollutant emission rates, the
averaging time for which they estimate ambient concentrations, the number and
type of pollutants for which they can compute average concentrations, and the
manner in which they adjust for the topography of the area under
investigation. With so many variables involved, most models are only used in
specific, limited applications.
At a minimum, all models require substantial source data. For a point
source, these data include the location of the source, stack height and
diameter, the velocity and temperature of the flue gas emissions, and the
release rate of the pollutant emission. The dispersion model will use these
data to predict ground level pollutant concentrations.
Because of the many variables involved in the use of dispersion models,
management must know not only if they are going to use. a model, but must be
able to identify the specific model and its data requirements. This is
especially true with regards to the temporal resolution of pollutant emission
rates. Will an emission inventory that reports emissions on an annual basis
be sufficient? Should it be seasonal? Monthly? Hourly? Management must
either choose a model whose requirements are consistent with the level of
detail of the inventory or upgrade the inventory to provide the additional
information required by the model.
3.1.4 REASONABLE FURTHER PROGRESS (RFP)
A regulatory mechanism which Congress added to the Clean Air Act in 1977*
is Reasonable Further Progress (RFP). RFP utilizes annual changes in
pollutant emission levels, as reported by the emission inventory, to measure
the success of the SIP in meeting its goals in nonattainment areas. As such,
it serves to verify that the control strategy adopted to bring a nonattainment
area into compliance is accomplishing its objective. Should RFP indicate that
progress is not being made, the state agency can alter its SIP to include more
extensive emission control regulations. Reasonable Further Progress is
notable in that it uses the emission inventory, for the first time, to measure
the effectiveness of a state implementation plan. The RFP mechanism implies
that by planning for, measuring, and keeping track of reductions in an
emission inventory, a state agency can ultimately bring areas into compliance.
RFP consists of two parts. First, a schedule is developed which
indicates total pollutant emissions (in tons per year) for a base year and the
projected emission level in 1983 that the agency believes will result in
compliance for the nonattainment area. The 1983 target date has been set by
Congress.** The purpose of this schedule is to verify that the emission
*Clean Air Act, as amended, November 1977—Sections 171(1) and 172(b)(3).
**Clean Air Act, as amended, November 1977—Section 172(a)(l) and (a)(2).
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reductions obtained are being accomplished at a reasonable and efficient rate
so that attainment by the prescribed time will take place. The second part of
RFP involves tracking the yearly reductions in actual emission inventory
pollutant levels. These reductions will come about as a result of the
increased controls mandated by the SIP in the nonattainment area. These
annual incremental reductions are then compared with the predetermined
schedule to determine the success of the SIP in this area. If the scheduled
reductions are not met, then the state agency must adopt additional measures
to reduce emissions. These might include increased enforcement, a stricter
new source review procedure, or more stringent emission limitations- The
entire mechanism of RFP schedules and tracking is explained in detail in
Reference 2.
The use of an emission inventory in RFP schedules and tracking is
mandatory. The inventory must be established for all sources which contribute
to the nonattainment pollutant. Fugitive point and area source emissions can
be very significant but may easily be overlooked. A true assessment of the
effect of emission reduction on air quality cannot be made if all significant
sources are not included in the inventory.
The inventory must be updated on an annual basis. Rather than make this
annual emission inventory a separate effort for nonattainment areas, state and
local agencies may decide to incorporate this work into an overall emission
inventory program for all areas within the agency's jurisdiction. Sources in
nonattainment areas will be segregated, as required, through the use of an
area quality control region (AQCR) identifier code attached to the source
records in the emission inventory.
3.1.5 PREVENTION OF SIGNIFICANT DETERIORATION
The Prevention of Significant Deterioration (PSD) is a congressionally
mandated policy* which is designed to protect the air quality in regions now
meeting National Ambient Air Quality Standards (NAAQS). The method
established for preventing the significant deterioration of air quality is a
preconstruction review of large new plants whose emissions will affect regions
of the country that are currently complying with NAAQS. The PSD rules apply
to a facility if (1) the plant is located in an area that is in compliance
with any NAAQS, (2) the potential emissions from the source of any regulated
pollutant exceeds 100 tons/year and the facility is in one of the 28
industrial categories listed in Table 3-1 (or for all other industrial
categories if the potential emissions exceed 250 tons/year), and (3) the plant
commenced construction on or after March 19, 1978. If these criteria are met,
the facility is required to undergo a preconstruction review by the state air
quality agency.
*Clean Air Act, as amended November 1977—Sections 160-169.
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TABLE 3-1. PSD INDUSTRIAL CATEGORIES
Fossil-fuel steam electric
plants of more than 250 million
Btu per hour heat input
Coal cleaning plants (thermal
dryers)
Kraft pulp mills
Portland cement plants
Primary zinc smelters
Iron and steel mills
Primary aluminum ore reduction
plants
Primary copper smelters
Municipal incinerators capable of
charging more than 250 tons of
refuse per day
Sulfuric acid plants
Nitric acid plants
Petroleum refineries
Lime plants
Phosphate rock processing plants
Coke oven batteries
Sulfur recovery plants
Carbon black plants (furnace
process)
Primary lead smelters
Fuel conversion plants
Sintering plants
Secondary metal production
facilities
Chemical process plants
Fossil-fuel boilers of more than
250 million Btu per hour heat
input
Petroleum storage and transfer
facilities with a capacity
exceeding 300,000 barrels
Taconite ore processing facilities
Glass fiber processing plants
Charcoal production facilities
Source: 40 CFR 51.
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The chief components of the PSD review Include (a) an area classification
system, (b) increments of air quality, and (c) best available control
technology (BACT). The area classification system was established for all
clean air regions to allow a moderate amount of industrial growth in all areas
but not allow industrialization to degrade air quality to the point where air
quality standards were jeopardized. All areas are classified Class I, Class
II, or Class III. States can reclassify areas to allow for increased
industrialization with public approval. Class I areas include the most
pristine areas of the country, such as many National Parks. Facilities whose
emissions impact these areas are subject to the greatest emission control.
Class II areas are areas of moderate growth and Class III areas are areas of
major industrial activity. Areas can only be designated Class III after a
public hearing.
For each area classification, PSD defines the increments of additional
pollutant (particulate and sulfur dioxide) that are allowed in an area due to
the effects of all new growth in that area. These increments are shown in
Table 3-2. As can be seen from this table, only small, incremental increases
will be allowed in the Class I areas. This will ensure that these existing
clean areas will maintain their relatively high level of air quality. If an
area were to be changed to Class II, additional growth and a higher pollutant
increment would be permitted provided the NAAQS were not exceeded.
TABLE 3-2. AIR QUALITY INCREMENTS
Area designation Primary ambient
air quality
Pollutant3 Class I Class II Class III standard
Particulate matter
Annual geometric mean 5 19 37 75
24-hour maximum 10 37 75 260
Sulfur dioxide
Annual arithmetic mean 2 20 40 80
24-hour maximum 5 91 182 365
3-hour maximum 25 512 700 1,300
aAll units in micrograms per cubic meter.
Source: 40 CFR 51.
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In specifying an incremental measure of air quality deterioration,
Congress, in the Clean Air Act, implied the use of dispersion modeling and
emission inventories. Thus, sufficient data for dispersion modeling must
exist in the inventory for all sources, including new and modified sources.
Once the source record is established, it can be used for additional emission
inventory related applications. The PSD program, in fact, requires that the
agency keep close track of all sources that are applicable to PSD review. The
agency must quantify the cumulative effect of all new sources on ambient air
levels. The emission inventory should be used to store these new source
records, with some easily identifiable code assigned to PSD related sources.
As each new PSD source is reviewed, all similar sources can be extracted from
the inventory so that the net affect on ambient air quality of all sources can
be ascertained through the use of a dispersion model.
To ensure that the increments are not quickly expended, the Clean Air Act
specified that each major new source install best available control technology
(BACT). BACT is determined for each industry on a case by case basis and will
not be discussed in detail here (see Appendix A for a definition of BACT).
This BACT requirement should be identified on the source emission inventory
record.
3.1.6 OFFSETS
While PSD regulations are concerned with new construction in clean air
attainment areas, the Emissions Offset policy involves new construction or
substantial modification of facilities in nonattainment areas. This policy
was originally issued by the EPA in its interpretative ruling* and
subsequently made a requirement of all SIP Revisions for nonattainment areas.**
The Offsets policy essentially states that no major source can be
constructed in an area where there is a NAAQS violation unless it obtains a
permit. This permit imposes stringent control requirements including emission
reductions or "offsets" that are larger than the emissions produced by the new
facility. This program ensures that any major facility constructed in a
nonattainment area will "offset" more emissions than it will produce and the
entire airshed will see a net reduction in emissions due to the construction
of the new source.
Since state agencies are charged with the administration of the Offsets
policy, each state will define which sources will be regulated. Typically,
new sources with actual emissions exceeding 50 tons/year, 1000 Ib/day, or 100
Ib/hr of particulate, sulfur oxides, nitrogen oxides, volatile organic
compounds, or carbon monoxide will be affected.
*Federal Register 41, December 21, 1976. pp. 55524.
**Clean Air Act, as amended, November 1977. Sections 172-173.
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Imposition of the Offsets policy requires that the owner of a proposed
facility find a source where an emission reduction can be effected. This may
be within his own plant, at another industrial facility, or at a government
facility. The emission inventory is the most direct vehicle for identifying
the location and amount of emission reductions available from a source.
Management, however, must plan its inventory data system to provide for this
capability. In addition to the standard facility data stored in the
inventory, a space on each facility record must be devoted to actual or
potential emission offset. Facilities which realize emission reductions due
to the closing down of a process or the installation of less polluting
equipment can then register these reductions with the agency. These offsets
can be maintained within the inventory to expedite review procedures for major
new sources in nonattainment areas.
3.1.7 ENVIRONMENTAL IMPACT ANALYSIS
Environmental Impact Analysis is a regulatory tool used to assess
potential environmental effects that result directly or indirectly from the
construction of new projects. For projects involving federal funding, the
analysis is required by the National Environmental Policy Act (NEPA).* Many
individual states have passed legislation which requires similar environmental
analysis for state-funded projects. These environmental reviews are contained
in Environmental Impact Statements (EIS). These statements must identify and
discuss the environmental effects of the proposed action and analyze and
compare alternatives. The applicability of these reviews is not explicitly
spelled out in the law and is often decided by the courts. Projects for which
an EIS is usually required include energy projects, dams, highway
construction, subsidized housing, shopping centers, and industrial park
developments. An EIS must concern itself with all environmental factors
including air and water quality, solid waste generation and disposal, odors,
and ambient noise levels. Only the air quality related aspects of an overall
environmental impact analysis will be discussed here.
To review the effects of a new source on local air quality, an agency
must first determine ambient air quality levels at the project site using, if
available, data from local ambient monitoring stations. The impact of the
project on these levels must then be determined. To do this, source emission
data of the detail contained in an emission inventory must be obtained. These
data should include not only pollutant emissions generated directly by the
project itself, but also increased emissions brought about by the projects
secondary impacts such as increased vehicular traffic and fugitive dust
emissions. Once quantified, these pollutant mass emission rates are used with
dispersion models to predict the overall effect of the project on local
ambient air quality. The use of a dispersion model in this application
establishes the amount and detail of emission data that are required. In
addition, for impact analysis projects, the expected growth of emissions must
be estimated to determine the project's effect on long term air quality
*40 CFR 1500-1508.
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maintenance. The quantification of all short and long term pollutant
emissions that is required for this review will also help agency management
define any additional regulatory actions (i.e., NSPS, NESHAPS, PSD, Offsets)
that are applicable. All relevant federal, state, and local air quality
regulations must be listed and the actual or projected status of all
pollutants determined. If the project involves secondary impacts, these must
also be quantified and added to the source's emission inventory record.
Finally, fugitive emissions that may result from the proposed action must be
calculated. When completed, a comprehensive emission inventory profile or the
proposed project will be available. A similar source record must be developed
for each proposed alternative that is addressed in the impact statement. When
all emission related data have been quantified, the entire data set for each
alternative is modeled separately to ascertain the effects on local ambient
air quality. The various inventory source records are retained until the
project is completed, and the source records for the selected alternative are
added to the inventory.
3.1.8 AMBIENT MONITORING NETWORK DESIGN
The emission inventory can be used to design ambient air monitoring
networks. Ambient air quality monitoring is a vital element in state and
local air quality programs to establish the compliance or noncompliance status
of state, county, or air quality control region with respect to NAAQS.^ The
accuracy of the ambient air quality data that are obtained and the
representativeness of the monitoring sites seriously impact on the usefulness
of the agency's air quality control programs.
The documentation of population exposure to ambient pollutant levels is
the single most important aspect of an ambient monitoring network. However,
there are a host of agency programs which need monitor data support. These
programs include those to:
Evaluate ongoing and planned control strategies;
Determine background concentrations;
Develop or revise national control policies for criteria and other
pollutants (includes New Source Performance Standards (NSPS), tall
stacks, and Supplementary Control Systems (SCS));
Provide data for model development and validation; and
Document pollution episodes and initiate episode controls.
The establishment or optimization of an ambient monitoring network to
provide support for these programs is an important task for management. The
design of this optimum network includes retaining representative existing
sites as well as selecting new sites. As this network will determine the
compliance status of the area, it must be designed in accordance with federal
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requirements-* Information which must be considered in this network design
include (1) existing and future plans for land use, (2) traffic counts and
other transportation data, (3) demographic statistics, (4) meteorological
data, (5) geographical information, and (6) existing air quality data-
Geographical placement of the monitoring site to accurately determine
pollutant concentrations can only be accomplished by detailed analyses of
large amounts of background information for the area under consideration.
Emission inventory data are necessary input to an air quality dispersion model
which can be used to estimate the impact of sources on selected geographical
areas. The selection of a model which is most appropriate for the area under
investigation will establish the level of detail that the emission inventory
must satisfy. Specifically, the number of sources to be included, and their
spatial and temporal resolution will be set by this dispersion model. The
predicted air quality impacts, in concert with demographic patterns, are then
used to select the monitoring sites which satisfy conditions for the maximum
number of agency programs. The use of an emission inventory can also aid the
agency in siting monitors which measure the impacts of a few selected sources;
for example, to monitor the impact of facilities which have been allowed to
convert to a higher sulfur oil or coal, as part of a SIP revision.
In cases where no dispersion model analysis is available, techniques do
exist for using only the emission inventory in the site selection process.
Methods such as the manual plotting of plumes downwind of major sources based
upon the prevailing wind direction are outlined in detail in the site
selection manuals published by EPA for the criteria pollutants.
3.1.9 ENFORCEMENT AND COMPLIANCE
Agency enforcement and compliance activities have a direct dependence on
air pollution control emission inventory data. These programs encompass a
variety of actions which concern themselves with individual emitters of
pollutants. Items such as scheduled annual source inspections, source
sampling, plant visits in response to ^.tizens complaints, and observed
visible emission violations require agency personnel to have a detailed
knowledge of a facility, its process operations, and its emission rates.
These data are Included in an emission Inventory and can be used to support
enforcement and compliance activities. However, agency compliance actions
require additional data that are not normally kept in an inventory. For
example, enforcement case histories and the establishment of compliance
schedules draw upon past inspection reports and notices of violation that are
not: normally maintained with the emission inventory. Because there is such a
strong interaction between the inventory and compliance-related activities,
management must plan for the continued, easy exchange of data from one
activity to the other.
*40 CFR 58.
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This exchange of information can work both ways. Compliance activities
that draw upon inventory data can also serve to verify and update that data.
New information on a source that is obtained as a result of the issuance of a
permit or the inspection of a facility should be included in the emission
inventory. This internal updating mechanism will ensure that the agency is
utilizing the latest available source information.
In spite of the inherent disadvantages an agency may face attempting to
incorporate all source data, including compliance records, into one control
file, management may choose this approach. Agencies which have automatic data
processing equipment can place some or all of their source records on a
computer. One such system that is currently used by many agencies in this
manner is the Emission Inventory System. This system consists of the Emission
Inventory System/Point Source (EIS/PS)^ and the Emission Inventory
System/Area Source (EIS/AS).' It was developed by EPA to integrate emission
inventory and permit data. The computer programs required are maintained
(updated) by EPA and the system is available to state and local air pollution
control agencies at no charge. Many individual state agencies have their own
computerized system which similarly combine emission inventory data with other
internal agency program requirements.
3.1.10 EMISSION TRENDS
Emission trends, in conjunction with ambient air quality trends, enable
management to adjust their planning and enforcement activities to changes in
source pollutant emissions within an area. The increases or decreases in mass
emissions may be plotted for any subdivision of the entire Inventory; e.g.,
specific "critical" areas, industrial categories, source sizes, etc. When
coupled with ambient air quality data, emission summaries provide a measure of
the cause and effect relationship between local source emission rates and
measured ambient pollutant levels.
Emission trends analysis has historically played a role in evaluating
pollutant control strategy selection. In the case of pollutants with easily
documented origins, such as sulfur dioxide, emission inventory trends have
been used to verify the effect of Imposing specific control strategies on
actual ambient air quality levels. This relationship can then be used in
future planning and strategy development efforts. For pollutants that have a
diversified industrial origin such as hydrocarbons, emission inventory trends
also Indicate the success (or failure) of imposing tighter emission controls,
although the correlation between reduced source emissions and measured
pollutant levels may not be as easily definable or traceable. For all
pollutants, trend analysis helps pinpoint those emission sources or categories
that are growing faster than others. Management can use this information in
periodic revisions of implementation plans to avoid ambient air quality
violations.
3.1.11 ENERGY ANALYSIS
Emission inventories play an Important role in energy analyses because
they contain energy use data for all stationary sources. The type of fuel
utilized by a facility and the fuel ash and sulfur contents are recorded in
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the inventory and updated on an annual basis. In addition, each facility that
is Included in the inventory is identified by one or more industrial
indicators. The Standard Industrial Classification (SIC) Code classifies the
source by its industrial type (e.g., chemicals and allied products, primary
metal industries, etc.). The Source Classification Code (SCC) identifies the
specific production processes used within the source and the size range of
this equipment. These codes can be used by the agency to segregate individual
industries from the total inventory for the purpose of conducting an energy
analysis. For example, if industry in an area wishes to convert its oil-fired
boiLers to coal firing, the agency can extract all potentially affected units
(e.g., boilers with capacities in excess of 100 million Btu/hr) from the
Inventory using SIC and SCC codes. Annual fuel oil use can be tabulated from
these individual source records and estimates of ambient pollutant
contribution can be made for the entire category using emission factors to
determine changes in pollutant emissions resulting from conversion of oil to
coal. For complex scenarios, energy use data can be used with dispersion
models to predict changes in ambient air quality levels. The emission
inventory permits the agency to calculate the effect of any proposed energy
strategy and in certain areas may permit the agency to revise Its SIP to allow
the use of cheaper fuels without exceeding ambient air quality standards.
3.1.12 RESEARCH
Emission inventories have played an Integral part in many air quality
related research efforts. These investigations have been conducted by state
and local agencies, universities, private contractors, and the federal
government. Their subjects have ranged from the local effects of one source's
emissions to studies which utilize emissions from all sources over a
multistate region. The emission Inventory is the definitive source of data for
studies which attempt to correlate emissions with environmentally related data
such as population disease rates. This use of the inventory to correlate
pollutant cause and effect relationships helps define national policies and
transcends its use in day-to-day agency programs.
State and local agencies may use inventories for such purposes as point
source model validation or Industrial energy density comparisons. Model
validation studies Involve applying comprehensive emission and meteorological
data to a dispersion model and recording the predicted air quality levels at
specific receptor points which are usually ambient monitoring sites. The
measured ambient air quality at these sites Is then compared with the
predicted concentrations. The difference between predicted and measured
values is an Indication of the accuracy of the model for the specific
application under Investigation.
Research into the causes of an ambient air quality violation may prompt
an agency Into conducting an extensive review of emissions from sources in the
area surrounding the monitoring site. These investigations begin with a study
of emission inventory data for all sources in the area and can progress to
investigations of additional emission related factors such as daily weather
patterns, traffic counts, street cleaning, and construction activity that are
not part of the inventory data base.
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The federal government, its contractors, universities, and independent
organizations use state emission inventory data to support multi-state
investigations. For example, the Northeast Corridor Regional Modeling Project
conducted by EPA (1980 to 1982) utilized emission inventory data to quantify
the level of interurban transport of ozone in the broad area from Washington,
D.C. to Boston. Emission inventories for all states in the study area were
combined to help develop and validate a regional scale photochemical
dispersion model to characterize pollutant generation and transport through
the northeast and to analyze various oxidant control strategies.
A similar study was undertaken by the Electric Power Research Institute
(EPRI). This organization in its Sulfate Regional experiment (SURE)8
focused on the nature of sulfur oxide behavior in the eastern United States.
Extensive emission Inventory data were collected from utilities in an attempt
to derive a quantitative method for relating emissions from the electric power
Industry to regional ambient air quality as measured by sulfur dioxide and
partlculate sulfate levels.
3.2 USERS OF THE INVENTORY
Emission inventory data are potentially useful to anyone requiring
information on air pollutant emitting sources. The source, location, type,
and amount of pollutant discharge as well as the type of Industry, process
rate, and energy consumption of any facility or group of facilities can be
obtained from standard inventories. Through the use of automated data
processing equipment, source data can be sorted by any single identifier or
group of identifiers, such that specific user oriented reports can be
generated. The list of actual emission inventory users is therefore quite
extensive and covers a wide range of public and private institutions. A
review of some of these users will serve to illustrate the extent of emission
inventory use.
3.2.1 STATE AND LOCAL AGENCIES
The most common users of emission inventories are the state and local air
pollution control agencies. Inventories represent an Integral part of their
control programs and are used continuously for a variety of internal
applications. Emission Inventories provide technical support for the range of
agency programs that have been previously described in this section. The key
factor in an agency's use of the inventory is planning. Management must plan
the inventory for all potential applications and ensure that the scope and
detail of source information contained in the inventory are sufficient for the
intended applications.
Other state and local agencies may use emission inventories for their
projects. Planning agencies concerned with air emissions from a new
stationary source such as a power plant, or a traffic-Inducing source such as
a shopping center, will consult inventory data prior to Issuance of a ruling.
Local conservation commissions require inventory input when examining items
such as solid waste disposal proposals or industrial expansion projects.
Agencies concerned with health problems are likely to contact air quality
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control agencies for information on major emitters of various pollutants. All
agencies concerned with the effect of its actions or proposed actions on air
quality can make use of the emission inventory. A comprehensive inventory can
also be used by the agency to evaluate the variety of decisions made by
others, Including adjoining states and federal agencies, which may directly
affect the state or local jurisdiction and Its people in a significant way.
3.2.2 CITIZEN USE
Air quality control agencies are established to serve the general
population. The agency protects the health of Its citizens and is ultimately
responsible to them. Thus citizens have a right to know how the agency
functions, and what information is used to support agency actions. Through
public hearings, citizens can participate in the agency's decision making
process. Among the responsibilities the agency has to these citizens is to
allow them open access to emission data such as that contained in an emission
inventory. The air quality control agency should serve these citizens by
maintaining an accurate and easily accessible emission inventory.
3.2.3 GOVERNMENT CONTRACTORS/INSTITUTIONAL
Consultants and universities will use Inventory data primarily for
research efforts. Their data needs are governed by the complexity of the
investigation and the requirements of any dispersion model to be used in each
study. In this regard, they act much like the control agency in their data
needs and the level of detail required.
3.2.4 FEDERAL (NON-EPA)
In addition to EPA, several federal agencies draw upon the source data
available in the emission inventory. Their use for this data is commonly for
preparation of an Environmental Impact Statement. Federal agencies are
required to file impact statements on new major construction under their
jurisdiction that could have a potentially adverse impact on the environment.
The air impact analysis section of these Impact statements draws upon emission
inventory data to quantify air quality levels.
In addition, many federal agencies use emission inventory information in
miscellaneous internal studies. The Department of Energy utilizes specific
energy user lists for general reporting purposes, summarizing energy use
patterns and providing energy use trend reports. The Department of
Transportation utilizes mobile source information taken from the emission
inventory in its planning process for highways and airports. The Department
of Housing and Urban Development will use inventory data in residential
heaiting studies. The Departments of Interior and Agriculture can use
Inventory data for assessment of Industrial categories of concern to them.
Any governmental planning agency that must consider environmental affects of a
proposed action is a potential user of emission inventory data. In order to
make environmentally correct decisions, they must have a reliable, accurate
source of air pollutant emission Information. An accurate, current, and
comprehensive emission Inventory of all sources will provide these data.
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References for Chapter 3.0
1. Criteria for Approval of 1979 SIP Revisions, OAQPS 1.2-095, U.S.
Environmental Protection Agency, Research Triangle Park, NC, September
1978.
2. Workshop on Requirements for Nonattainment Area Plans, OAQPS 1.2-103,
Volume 19, U.S. Environmental Protection Agency, Research Triangle Park,
NC, January 1979.
3. Workbook for Comparison of Air Quality Models, EPA-450/2-78-028a, U.S.
Environmental Protection Agency, Research Triangle Park, NC, January 1979.
4. Turner, D. B., "Atmospheric Dispersion Modeling, A Critical Review,"
Journal of the Air Pollution Control Association, 29(4):502-519, April
1979.
5« Guidelines for Air Quality Maintenance and Planning and Analysis, Volume
XII; Applying Atmospheric Simulation Models to Air Quality Maintenance
Areas, EPA-450/4-74-013, U.S. Environmental Protection Agency, Research
Triangle Park, NC, September 1974.
6. The Emission Inventory System/Point Source User's Guide,
EPA-450/4-80-010, U.S. Environmental Protection Agency, Research Triangle
Park, NC, May 1980.
7. The Emission Inventory System/Area Source User's Guide, EPA-450/4-80-009,
U.S. Environmental Protection Agency, Research Triangle Park, NC,
May 1980.
8. EPRI Sulfate Regional Experiment; Results and Implications; EPRI
EA-2077-SY-LD, Project 862-2, September 1981.
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4.0 INVENTORY DATA REQUIREMENTS
In order to formulate decisions for pollution control or reduction
strategy, some basic information concerning sources and emissions is
required. The emission inventory file serves as the repository for this
information. The amount of information and the detail or resolution of the
inventory data should be consistent with the intended use. However, a
comprehensive inventory, of the detail described in this manual, should be
maintained by the agency to satisfy both regulatory and functional
requirements. A goal of emission inventory planning is to obtain and maintain
within the inventory the level of source and emission data that is needed for
all anticipated uses of the inventory. Air quality dispersion modeling, more
than any other agency activity, will determine the level of temporal and
spatial resolution of the data maintained in the emission inventory file.
Background documents on each dispersion model should be consulted to determine
the specific temporal and spatial resolution requirements of each.
Automatic data processing is strongly suggested to handle the large
amount of data that are needed for the comprehensive inventory.-'- Various
programs can be initiated that will facilitate data edit checks and sort and
report data according to desired pollutants, source categories, etc.
It is not always necessary to conduct an inventorying activity that
includes all of the criteria pollutants. Rather, one pollutant, for a number
of reasons, may present a more serious problem than another and be subjected
to more detailed analysis. Thus, the scope of a specific agency program may
require an inventory effort that can be restricted to cover only those point,
area or mobile sources that are directly related to the pollutant of
interest. This is possible for the pollutants, SOX, NOX, hydrocarbons,
carbon monoxide, particulate matter, and lead which are now maintained in the
emission inventory file. Additional hazardous pollutants may be of interest
to the agency and, if possible, the inventory should be expanded to include
these pollutants.
The grouping of emission sources into categories is done to identify the
major sources of emissions and assist in the development and assessment of
control strategies. At a minimum the agency should be prepared to report
source and emission data from those categories shown in Table 1-1. More
detail is desirable and made mandatory by regulation in many situations.
The comprehensive inventory is comprised of three types of sources:
point sources, area sources, and mobile sources. Point sources consist of
identifiable points of emissions that release pollutants into the atmosphere,
usually greater than 100 tons per year of any pollutant. Area sources consist
of a number of smaller sources, not classified as point sources, which are
defined by geographic boundaries and engaged in a specific activity that
provides a means of estimating the collective emissions from the sources.
Mobile sources are nonstationary emission sources, including both highway and
off-highway transportation sources. Emissions from mobile sources result from
fuel combustion and crankcase and certain other evaporative VOC emissions.
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4.1 POINT SOURCES
The point source is an individual, stationary source of emission that is
maintained in the point source file. Emissions are the result of process
operations and a facility or plant may contain several emission producing
operations which can be vented to one or several point sources of emission.
The inventory of point sources can be considered to be much more accurate than
an area source or mobile source Inventory. This accuracy is due to the detail
required for characterizing and analyzing the operations of each point
source. Because more detailed information is obtained concerning the process
throughputs, process parameters, and operating schedules, emissions can be
estimated more accurately and with greater geographical and temporal
resolution.
Any source emitting in excess of 100 tons per year of any criteria
pollutant is generally considered a point source- However, there is no
uniform use of that emission rate limit. The higher the cutoff limit, the
fewer the facilities that are included in a point source inventory; a lower
limit would result in the inclusion of more sources.
The point source inventory has three levels of complexity. In order of
increasing complexity they are: the plant level, which denotes a plant or
facility that could contain several pollutant emitting activities; the process
level, representing the unit operations of specific source categories; and the
point level, where emissions to the ambient air from stacks, vents, or other
points of emission are characterized. Information concerning the preparation
of point source inventories is presented in Volume II of this series.2.
4.1.1 PLANT LEVEL
The first step in preparing an inventory of point sources is to collect
information which identifies plants or facilities which contain one or more
point sources of emission. Each plant identified within an area Is assigned a
plant number and It is further Identified by geographic descriptors such as
air quality control region, state, county, city, street and/or mailing address
and UTM grid coordinates (or latitude/longitude). A plant personnel contact
should also be identified to facilitate communication and interaction with the
plant. Additional information gathered regarding the facility are annual fuel
consumption, process throughput, hours of operation, number of employees and
the Standard Industrial Classification (SIC) code of the plant. SICs are
prepared and published by the Office of Management and Budget of the U.S.
Government. A given facility will have only one SIC denoting the principal
economic activity of the facility.^
4.1.2 PROCESS LEVEL
A plant can consist of various processes or operations. Each process can
usually be Identified by an EPA source classification code (SCC) which has
associated with it an SCC emission factor to allow calculation of emissions
from specific process operations and equipment.^»•*
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The Information necessary for the establishment of an inventory at this
level includes source identification information (as previously described for
plant level); the periods of process operation (daily, weekly, monthly,
annually); operating rate data, including actual, maximum and design operating
rate or capacity; fuel use and properties data (ash, sulfur, trace elements,
heat content etc.); and identification of all pollution control equipment and
their associated collection efficiencies (measured or design).
Emission estimates should identify the estimation method used; e.g.,
actual stack sampling, material balances, emission factors, engineering
analysis, or other estimation techniques. All assumptions, procedures, and
analyses should be documented to provide sufficient information for evaluation
of the procedures used and the resulting emission estimates-
4.1.3 POINT LEVEL
Each stack, vent, or point of emission which meets or exceeds the
specified point source emission rate designation is identified as a point
source within a plant. Information obtained from the point source inventory
level is utilized in the design, testing and application of mathematical
models for the correlation of air pollutant emissions with ambient air quality.
Basic information such as location (UTM Coordinates), stack height of the
emission point, diameter of the stack, emission rate , method of
determination, gas exit velocity from the stack, the efficiency of control
equipment, and emission rates during normal and upset conditions, are
parameters necessary for establishment of a comprehensive inventory and for
modeling programs. For modeling, the precision required in specifying the
position of a source is partly related to the position of the receptor. Some
dispersion modelers concerned with the impact of a point source on nearby
receptors have asked that the location of point sources be determined within
10 meters.
Although such a high degree of precision in specifying location may only
be necessary in a limited number of applications, It is recommended that the
location of point sources be reported with a resolution of at least 100
meters. This level of resolution represents that specified for the existing
data In the National Emissions Data System (NEDS).
4.2 AREA SOURCES
An area source represents many sources of emissions which are too small
to be classified as point sources and for which data are maintained
collectively in the area source inventory. Although these sources may
individually emit only small quantities of pollutants, the collective
emissions may have a significant impact on air quality. Mobile sources are
regarded as area sources. However, mobile sources are inventoried separately
from stationary area sources.
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The area source data file is needed to provide a record of source and
emission data for categories of sources that are small and too numerous (e.g.,
residential heating units) to include in the point source file. Area source
emissions for a category are estimated by multiplying an emission factor by
some known indicator of collective activity for the source category which can
be correlated with emissions; e.g., fuel burned is the activity factor used
for home heating units. The selection and structuring of area source
categories, in addition to providing a means for the collective estimation of
emissions from the category, determines the type and amount of data that are
maintained in the area source file and the usefulness of the inventory in
agency activities, such as assessing the effects of control measures. Major
area source categories include fuel consumption, solid waste incineration,
process losses (e.g., evaporation of VOC), and miscellaneous emission sources
such as fires and windblown dust. Emissions from miscellaneous sources can
predominate in many locations. See Reference 6 for a more detailed discussion
of preparing the area source inventory.
The area source inventory can be conducted at three levels as well. The
normal inventory levels include the AQCR, county, and grid level. The AQCRs
are areas determined by the Federal government for air pollution planning
purposes, while the county is defined by jurisdictional boundaries and the
grid level by a coordinate system for modeling usage. An area source
inventory will require the use of apportioning techniques to allocate
emissions from the area for which data are available to the AQCR, county and
grids.
Area source emissions data compiled at the county (or county equivalent)
level will provide sufficient spatial resolution for some uses of the
inventory. County limits are logical boundaries for compiling an emission
data base for two reasons. The first is due to the areawide nature of some
pollutant problems; e.g., photochemical oxidants are generally not a localized
problem, but rather, form after several hours, or in some cases, days as a
result of reactions among precursor pollutants emitted over broad geographical
areas. Consequently, less spatial rebolution is generally required for
volatile organic compound (VOC) emissions than is necessary for the other
pollutants for which national air quality standards exist. The second reason
for compiling emission inventories on a county basis is related to data
availability. The county represents the smallest basic jurisdiction unit for
which various records are kept that are appropriate for use in developing area
source emission estimates. Thus, because it provides sufficient resolution
for the less data-intensive source/receptor relationships, and because of the
convenience it affords the agency, the county is the optimum jurisdictional
unit for compiling inventories that will be used for such tasks as developing
an oxidant control strategy.-'- Apportionment of pollutant emissions from
counties to grids, however, may be required for the dispersion modeling of
pollutants other than VOCs to help in identifying local problems and
developing solutions to those problems.
4-4
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4.2.1 AIR QUALITY CONTROL REGION LEVEL
The Clean Air Act and its amendments directed the Federal government to
designate AQCRs for high pollution urban areas- At present, there are 247 Mr
Quality Control Regions In the United States and its territories. Within the
50 states, the boundaries of the AQCRs tend to coincide with those of counties
or states. However, many AQCRs are both interstate and intrastate, depending
on the activity and geography of the area. Portions of as many as four states
may be included under the limits of one AQCR. The boundaries for the AQCRs
can be found In Title 40 of the Code of Federal Regulations.
The data required for an inventory on the AQCR level may be aggregated
from summary statistical data of the counties. The estimation of pollutant
emissions is based on the use of correlative factors such as total fuel usage,
number of residential units, or other aggregate information for the counties
within the AQCR. When the AQCR encompasses only a section of a county, the
data concerning that area will have to be apportioned from the county total.
Distribution functions based on population, dwelling units, number of
commercial Installations, or other common factors are used to estimate the
fraction of county activity apportioned to the AQCR.
In some cases, an emission inventory for pollutants may need to extend
beyond the jurisdiction of an agency. For example, a metropolitan area will
often encompass a number of counties and may overlap into several states, as
in interstate AQCRs. In these instances the inventory efforts of all of the
agencies should be coordinated so that the results will be interchangeable and
useful to all groups involved.
4.2.2 COUNTY LEVEL
Sources of information at the county level, may be provided by EPA
documents, by local and regional studies dealing with city, county, or
statewide categories, and statistical data from various Federal, state, or
local agencies. The necessary data are usually available on a countywide
basis and provide an excellent foundation for an Inventory. Statistical data
for census tracts can be combined to calculate values for county level usage.
As at the AQCR level, emissions can be estimated by applying emission
factors to indicators of source category activity levels. These indicators
will vary for each source category. For example, stationary source fuel
combustion emissions can be estimated from fuel-use reports for user
categories and incineration emissions can be estimated from population data.
4.2.3 GRID LEVEL
In certain Instances for the purpose of dispersion modeling of area
sources, much finer geographical resolution will be required than that
available at the county level. The UTM coordinate system is commonly used to
impose uniform grid zones onto geographic areas to allow for convenient
apportioning of county activity level and emission data to grid levels.
Again, the apportioning of the data is performed using distribution functions
derived from population, commercial/institutional, Industrial and
transportation information.
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4.3 MOBILE SOURCES
Mobile sources such as vehicles, aircraft, and railroads, are a
significant source of emissions (see Table 1-1). They constitute an important
segment of the area source category and, as Is the case In this emission
inventory series, are often considered as a separate category distinct from
area sources. However, in presenting methods for inventorying mobile source
emissions in Volume IV,^ and consistent with the methods discussed in AP-42,
only those emissions resulting from the combustion of the fuel used to power
the mobile sources and certain evaporative losses have been classified as
mobile source emissions. Fugitive emission resulting for example, from the
re-entralnment of dust by vehicle travel over unpaved roads or the use by
aircraft of dirt airstrips, are treated as area source emissions In Volume
III.6
The emissions from motor vehicles are usually calculated from total
vehicle miles traveled (VMT). VMT data are obtained from traffic studies
conducted by local or state transportation agencies. A VMT breakdown by
vehicle type, fuel, speed and other factor is used to account for the effect
of vehicle operation on emission rates*
If measured VMT data are not available, the VMT for an area can be
estimated by one of several possible techniques. Gasoline sales, for example,
can be used to compute VMT through the use of average factors for the number
of miles per gallon. State gasoline sales tax data or published gasoline
sales data are sources of information for the determination of fuel
distributed. Fuel sales can also be used to estimate off-highway source
activities by agricultural equipment, industrial and construction equipment,
or smaller gasoline-powered machinery and motor vehicles. However, fuel sales
data are not useful for other off-highway sources. Vessels and railroads
powered by several types of fuels, for example, do not necessarily use fuel in
the area of purchase and correlation factors other than sales must be used to
apportion emissions. Aircraft emissions are inventoried by the relating
number of landing-takeoff (LTD) cyclee performed at an airport to emissions.
4.3.1 AIR QUALITY CONTROL REGION AND COUNTY LEVELS
The mobile source, which is one category of area sources, is inventoried
at the AQCR and county levels by using procedures similar to those discussed
for area sources. Where available, state and county traffic counts,
transportation studies, and national statistics are used with proper
distribution functions to determine the VMT within an area. Because an AQCR
tends to encompass several counties, basic data are obtained from local and
county agencies and aggregated to the AQCR level.
Aircraft activity is determined by LTO data for passenger, freight, or
military flights obtained from airport, county, or FAA studies. Emission
factors are used to compute the quantity of pollutants released by LTO
activities. Vessel emissions are computed by the quantity of fuel used and
emission factors for both port and underway activity.'
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4.3.2 GRID LEVEL
Distribution functions based on various transportation factors are used
to apportion mobile sources to grid area for dispersion modeling. The
apportioning factors used to allocate VMT and fuel consumption to the proper
grids can be based on population, vehicular activity, the number of fuel
suppliers, or other considerations. However, not all transportation emission
sources can be allocated accurately using the above apportioning factors.
Traffic volume counts are the most direct and accurate data for apportioning
motor vehicle activity. VMT information, if available, may also be updated
from fuel-use information within the region. Airport emissions are assigned
to the grid that contains the airport. Railroad activities produce emissions
from both rail lines and railyards, and vessels produce emissions both in port
and in transit. Methods have been devised for allocation of these emissions.
4.4 TEMPORAL RESOLUTION
Annual emissions data have been gathered in most inventory efforts.
However, for certain agency programs, greater temporal resolution In the form
of seasonal, daily, or hourly emission data are required (hourly emission
estimates are needed for several photochemical atmospheric simulation
models). Definite seasonal and diurnal variations in emissions exist for
certain source category/pollutant combinations due to changes In both emission
factors and activity levels. For example, in addition to an increase in
gasoline consumption during the summer months, evaporative organic emissions
from automobiles and gasoline handling and storage operations (both major
contributors of organic emissions in urban areas) will Increase significantly
at higher summertime temperatures. Other sources (e.g., exterior surface
coating), will also produce higher oxidant season emissions. Conversely, some
sources will exhibit less activity and, hence, lower emissions during the
summer months. Hourly variations are also significant for many sources; e.g.,
mobile sources, space heating, asphalt paving, and pesticide applications.^-
The annual emission inventory can be adjusted to reflect conditions that
exist during the time period of interest. The basic provision for adjusting
the inventory includes identifying those variables that Influence emissions
and substituting appropriate values that reflect conditions during that time
period. As noted, two of the major variables are source activity and changes
in emission factors due to temperature. Changes in wind speed or the seasonal
modification of a product (e.g., use of gasoline with a lower vapor pressure
in summer months) can also affect emission rates.^
The temporal resolution of emissions can be determined by contact with a
source or by the use of technically rational temporal apportioning methods
developed for the categories subject to significant temporal variation in
emissions. Appropriate temporal adjustment is not usually afforded simply by
apportioning annual emission rates into shorter time intervals. Summertime
emission rates for many sources cannot normally be estimated accurately by
simply dividing annual emissions by four and special adjustment techniques are
desirable. A time-dependent Inventory was used by EPA for the Regional Air
Pollution Study (RAPS) in St. Louis, Missouri.8 Adjustment techniques, as
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specified in the RAPS study, are dependent on the specific source category/
pollutant combinations under consideration. The agency should become familiar
with these techniques and other technical developments for determining
emissions as a function of time.
References for Chapter 4.0
1. Procedures for the Preparation of Emission Inventories for Volatile
Organic Compounds, Volume I, Second Edition, EPA-450/2-77-028, U.S.
Environmental Protection Agency, Research Triangle Park, NC, September
1980.
2. Procedures for Emission Inventory Preparation - Volume II: Point
Sources, EPA-450/4-81-026b, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1981.
3. Standard Industrial Classification Manual, Office of Management and
Budget, Washington, DC, 1972.
4. AEROS Manual Series, Volume I, AEROS Overview, EPA-450/2-76-001, U.S.
Environmental Protection Agency, Research Triangle Park, NC, February
1976.
5. AEROS Manual Series, Volume II. AEROS User's Manual, EPA-450/2-76-029,
U.S. Environmental Protection Agency, Research Triangle Park, NC,
December 1976.
6. Procedures for Emission Inventory Preparation - Volume III; Area
Sources, EPA-450/4-81-026c, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1981.
7. Procedures for Emission Inventory Preparation - Volum IV: Mobile
Sources, EPA-450/4-81-026d, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1981.
8. Regional Air Pollution Study. Emission Inventory Summarization,
EPA-600/4-79-004, U.S. Environmental Protection Agency, Research Triangle
Park, NC, January 1979.
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5.0 EMISSION INVENTORY DATA COLLECTION
The major steps in the process of establishing the inventory data base
involve:
Establishing a list of point, area and mobile emission sources,
Contacting each point source to obtain quantitative process and emission
data,
Collecting activity level data for area and mobile sources, and using
this data to develop emission estimates,
Analyzing data to determine if all necessary data are available and
technically satisfactory,
Filling in any data gaps that exist in the emission data base by
recontacting point sources or contact with new sources of activity level
or emission data,
Processing the data (including establishing source pollutant emission
rates) for use in automated data processing equipment,
Editing and validating the processed data, and
Providing for periodic inventory maintenance and updates.
Because the data needs for each inventory effort will vary, there is no one
"best" way to effectively collect all needed emission inventory data. Data
collection methods for an urban hydrocarbon inventory involving hundreds or
thousands of sources, for example, will be different than that for a local
inventory of vinyl chloride manufacturers.
5.1 INFORMATION SOURCES
In order to ensure that all emission sources are included in the emission
inventory, a systematic approach must be used for obtaining this information.
Traditional sources of point, area, or mobile source data should be used
initially to draw up source lists. These sources include:
Point Sources
State Departments of Commerce and Labor
State Permit/Registration Files
State and Local Industrial Directories
State and Local Tax Offices
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Dun and Bradstreet, Industrial Directory
Standard and Poors, Register of Corporations
Thomas Register
Local Directory of Manufacturers
Regional Planning Commissions
Trade and Professional Societies
Area Sources
State Agencies
Regional Planning Commissions
Annual Housing Survey—Bureau of the Census
Statistical Abstract of the United States—Bureau of the Census
Mineral Yearbook—Bureau of Mines
Census of Agriculture—Bureau of Census
Census of Retail Trade, Area statistics—Bureau of the Census
Energy Data Reports—Department of Energy
FAA Air Traffic Activity
Other Statistical Government Publications
Mobile Source
Highway Statistics—Federal Highway Administration
Vehicle Mile Traveled Data—State Department of Transportation
Regional Planning Commissions
The value of each of these sources, many of which are statistically compiled
for states and counties, are discussed in other volumes of this
Series. >2>3 Collectively, these references will provide much of the basic
data for compilation of source and emission data, particularly for area and
mobile sources, within the inventory file.
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5.2 DATA COLLECTION
For a point source, the name and address and the telephone number of
responsible plant personnel should be obtained for each facility when
establishing a comprehensive listing of sources- This information should be
provided by the facility when it completes and returns an emission inventory
questionnaire to the agency or completes facility permit applications. For
inventory efforts that involve a limited number of sources, a telephone call
or visit to each facility can be made.
In the case of area and mobile sources the agency is not required to
contact emitting sources. Emissions are calculated using activity levels
(e.g., fuel consumed by the residential sector, vehicle miles traveled, and
aircraft landing and takeoffs) and emission factors developed for specific
source categories, travel modes, etc. Activity levels are obtained from
statistical sources of information: normally, federal and state agencies;
suppliers of fuel or other activity-related process feedstocks, (e.g., dry
cleaning or degreasing solvents and retail paints); and state and local
agencies engaged in activities such as transportation, land use planning and
energy.
5.2.1 QUESTIONNAIRES
The preferred method to obtain emission-related data from large numbers
of sources is the questionnaire. Questionnaires can take many forms, from the
one page sheet directed at a specific industry (i.e., service stations) to a
multipage effort mailed to large, complex manufacturing plants. A great deal
of effort has been devoted to the development of a questionnaire that
satisfies all data needs, and that can be accurately filled out by industry.
A standard questionnaire, the Air Pollutant Emission Report, has been
developed by EPA in response to this need (EPA Form 3520-4A (9-78)) and is
included as an appendix to Volume II of this Series. Agencies planning to
develop their own questionnaire should consult an EPA publication entitled
"Development of Questionnaires for Various Emission Inventory
The emission inventory questionnaire has three basic elements: the cover
letter, the instructions, and the questionnaire itself. To ensure that the
questionnaire receives the prompt attention that it deserves, the cover letter
should include the following: 5
Identification of the regulatory requirements which necessitate
completion of the questionnaire by the facility and the penalties
incurred by noncompliance
A statement of the purpose of the questionnaire
Provisions for confidentiality, if applicable
A date for return of the completed questionnaire
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The name (and telephone number) of a person within the agency to contact
for assistance in completing the questionnaire
Figure 5-1 presents a typical format for a cover letter. Although a key
element in the cover letter is the statement concerning the applicable
regulations and potential penalities for failure to respond, the agency should
foster cooperation rather than emphasizing penalties for noncompliance.
Questionnaire instructions should be comprehensive enough to adequately
explain how to answer the questions. If the questionnaire is a general one
designed to be applicable to all industries, the instruction sheet should
delineate which sections or pages should be completed for specific processes
or facilities. Figure 5-2 presents a typical general instruction sheet. If
the responses to questions are designed for direct coding to computer input,
the instructions should explain how to enter numbers properly. An instruction
sheet that explains how the process flow schematic is to be presented must
also be included.
The questionnaire itself will contain two sections, a general information
section and a process details section. The general information section
identifies and locates the facility and solicits emission and activity level
data for the facility as a whole. The process details section covers the
specific operations at the facility and solicits information on equipment,
activity levels, and emission points for each process. The following
information is typically requested (or is to be verified) in the general
Information sections.
Facility name, location and mailing address
Facility plot plan showing location and identification of emission points
Other identifying information, including facility operating schedules,
number of employees, SIC code and plant UTM coordinates
Person designated as plant contact for air quality-related questions
Confidentiality, if desired, and a detailed justification of the reasons
why specific information should be so classified
Whenever possible, all known information should be filled In by the agency
before the questionnaire is mailed. This serves to minimize the time required
by the facility to complete and return the questionnaire. The facility is
directed to correct any errors in the information entered by the agency.
The process details section solicits information needed for the
characterization of emissions from all sources within the facility. The line
of questioning here should proceed from information that is generally known by
the facility, that is, from the identification of emission processes and
equipment, to the more obscure data on specific pollutant emission rates.
This section usually requests some or all of the following information:
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(OFFICIAL STATIONARY HEADING)
LAWS OF THIS STATE REQUIRE THAT THE INFORMATION REQUESTED BELOW
BE SUBMITTED AS SPECIFIED TO THE (AGENCY).
FAILURE TO RESPOND COULD RESULT IN
(LOCALLY APPLICABLE REGULATIONS OR PENALTIES)
Gentlemen:
The (agency) is conducting an inventory of atmospheric emissions of
organic compounds from stationary sources in (area). The results will be used
in the formulation of control plans as required by (applicable regulations).
You are requested to provide information necessary for the assessment of
emissions from equipment and processes in your plant by completing the
enclosed questionnaire.
Please mark clearly any information, other than emissions data, which you
consider confidential and include your reasons for doing so in your cover
letter. In accordance with (state statutes) your claim for confidentiality
will be evaluated and you will be notified of the decision regarding the
validity of your claim. In the event of a decision not to grant
confidentiality, you will have the right to appeal in accordance with (state
statutes).
This questionnaire has been designed specifically for your industry;
therefore, you should answer each question. If the space provided is not
adequate, feel free to either copy the form, request an additional copy, or
use a separate sheet.
The required data should be submitted no later than (date). A return
envelope is included for your convenience. Any questions regarding this
questionnaire should be forwarded to (name of Agency personnel) at (phone
number). Your cooperation and prompt response will be appreciated.
Sincerely,
(Name)
(Title)
Figure 5-1. Sample format for a questionnaire cover letter.
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(SAMPLE)
Ci'.N! RAL INSTRUCTIONS
ORGANIC SOI.Vr.NT SOURCF. QUKSTIONNAIRK
1. All questions should be directed to (name of agencv contact) (phone
aumber).
2. This questionnaire was designed to obtain information from a wide variety
of solvent user'.,. The complete questionnaire me hides the following
pages:
Page A - General Information
R - Degreasing Operations
C - Dry Cleaning Operations
D - Protective or Decorative Coatings
E - Fabric or Rubberized Coatings
F - Miscellaneous Surface Coatings
G - Ovens
H - Printing
I - General Solvent Use
J - Bulk Solvent Storage
K - Control and Slack Information
You have received onlv the pages that our records show would pertain to
your operations. All recipients should complete pages I, J, and K. If
certain pages appear to be missing please contact (name' of agencv contact).
3. Data should reflect calendar vear (year) or (>ear), whichever is more
readily available. Specif)' any other 12-month period that may be used.
A. Fill in the descriptive information and amounts of solvent use or solvent
containing materials for each device' opera Lin/, under countv permit as shown
in the example on each page.'. (Note: these examples are tor illustration
only and may not represent actual operating conditions.) If data are not
available on an individual device basis, use best est imates from total
plant usage.
5. If the type(s) and/or percentages of solvents in coatings, inks, etc.. are
not known, include sufficient information on the manufacturer, tvpe and
stock number so that this breakdown can be obtained. A cony ol the sup-
plier's invoice would be adequate. Do not simply specify that the material
meets Rule 66 requirements,
6. Confidential or proprietary information mav be so specified by including
a cover letter with the returned questionnaire. The data that will be
generated during this program wi 1 1 be public informal ion. However tin-
data on specific sources will be presented in a m.mn''t that will conceal
the individual emission source to all but staff personnel. It is our
understanding that the data will not be used for enforcement purposes;
however, it must be recognized that this information 'nav In- emp loved in
the formulation of regulations which mav ul' imately al I CM t the spec" i I ic
sources included in the study. Specify in writing what data are
considered confidential or proprietary.
Figure 5-2. Sample of questionnaire general instruction sheet.
5-6
-------
Process flow diagrams with equipment descriptions
Activity levels for sources of emissions
Operating schedule of process/equipment contributing to emissions
Control system descriptions
Efficiency of control systems
Stack data
Emission rates from stacks, vents, and fugitive sources
Stack emission test results and test conditions
Physical and chemical characteristics of emissions
Some general rules for formulating questionnaires are:
1. Ask the right questions—those which solicits information that the
agency needs to estimate emissions from the facility;
2. Be brief—questions that are short and to the point are easier to
understand and will encourage facility response; and
3. Use multiple choice questions or check boxes when possible—they
also facilitate response and are especially useful if the
questionnaire is formatted for computer input.
Because some facilities will need special help with the preparation of
questionnaires, the agency must plan to provide such assistance. In addition,
to develop a comprehensive emission data base, an organized follow-up program
should be conducted by the agency to ensure return of all questionnaires.
The returned questionnaire is a part of the documentation or the emission
inventory. It is retained on file as documentation along with records of all
followup recontact information.
5.2.2 FILLING DATA GAPS
Returned questionnaires, facility interview reports or statistical data
for determining area and mobile source activity levels and emissions must be
thoroughly reviewed by agency personnel. This review will include checking
the questionnaire for missing or questionable information, follow-up contact
to obtain unreported information or to clarify questionable responses, and an
in-depth technical analysis of the collected data to ensure its validity. The
most direct and productive method of filling point source data gaps is with a
follow-up phone call. This personal contact is especially effective if the
data gaps are not extensive in scope. Otherwise, a second mailing to all
5-7
-------
delinquent questionnaire recipients will be required. Ideally, all incoming
source data will be checked and follow-up activities conducted by agency
personnel familiar with the specific industry. Questionable data due to
misinterpretation, errors in transcription, or erroneous assumptions by the
sources can, therefore, be quickly noted and follow-up evaluations conducted.
All data received must be tabulated and/or transcribed into a format that will
allow assessment of the adequacy of the data and entry into the data file.
Area source data concerning activity levels and emissions must also be
subjected to a quality assurance program. In addition to routine checks for
transcription and calculation errors, data sources and procedures should be
evaluated. Information used to estimate area source activities and emissions
should be calculated, if possible, using alternative data sources.
5.3 CALCULATION OF EMISSIONS
The facility will be requested to report pollutants emitted and the
emission quantities for each. The measurement method used for determining
emissions should also be Identified by the facility.
Emission data from the facility must be carefully assessed by agency
personnel to ensure that all procedures used and process conditions maintained
during the test program were consistent with the obtaining of representative
data. In the absence of data on source emissions, agency personnel must use
engineering judgment and knowledge of the specific process to quantify
emission rates. Technical references relative to the process or similar
processes can be consulted to aid in this determination. (See References 1 2,
3, and 6 for identification of some of the more useful publications relating
emissions to process design and operating parameters.)
There are a number of methods currently used for establishing emission
rates, which include:
1. Stack emission tests
2. Process material balances
3. AP-42 emission factors6
4. Other emission factors
5. Guess (educated or otherwise)
Stack tests provide the most accurate measure of process emissions, if
properly conducted during a period which is generally representative of
average annual operating conditions. Process material balances, in certain
cases, provide a reliable measure of mass emissions. A commonly used example
of this method is sulfur oxide emissions from oil-fired boilers. Since
virtually all the sulfur contained in fuel oil is converted to sulfur oxide,
emissions can be calculated knowing the fuel firing rate and fuel sulfur
content. Similarly, in certain instances, one can estimate uncontrolled
process solvent emissions if the solvent feed rate, final product solvent
percentage, and process production rates are known.
-------
In most situations where source test information is not available or
material balances are not technically viable, the usual method of determining
pollutant emissions for a given source type is to make generalized estimates
of typical emissions from these sources using emission factors. Emission
factors estimate the rate at which a pollutant is released to the atmosphere
as a result of some process activity. Emission factors for each source
category have been derived from emission tests, material balance calculations,
and other analytical techniques applied to sources within that category.
While the emissions calculated using these average values may differ from
actual emissions for a specific facility, overall they provide a relatively
accurate estimate of pollutant release rates for the source category under
consideration. EPA's AP-42, is the most comprehensive listing of emission
factors currently used.
5.4 DATA ASSESSMENT AND QUALITY ASSURANCE
In order to ensure that all source data collected for the emission
inventory are accurate and have been correctly transcribed onto computer input
cards (when automatic data systems are used), data validation procedures must
be used. These procedures are designed to ensure that source identifier and
process information, such as UTM coordinates and stack data, as well as actual
source emissions levels, will be checked for errors or values that are
atypical of given sources. For automated systems, this validation procedure
essentially consists of two parts. An edit check is first run on all
keypunched cards. This check will identify cards that are incorrectly coded
or left blank without an explanation. This step helps to sort out simple
clerical and keypunch errors. The source record cards are then checked to
ensure that all data fall within prescribed limits set by the agency for major
source categories. A typical set of these checks for boiler data is shown in
Table 5-1. This validation procedure will automatically reject data points
that are beyond the limits normally found for that item. Should the data as
initially reported prove correct, it can easily be reinserted. Similar
validation techniques are used to check emission inventory data which are
compiled manually. Maximum and minlaium values of certain emissions and
process parameters by SCC, used by the National Emissions Data System, are
available from EPA's Office of Air Quality Planning and Standards, Research
Triangle Park, NC 27711.
Typical emission inventory errors are presented in Table 5-2. This list
is not exhaustive but does highlight commonly found problems. In order to
minimize the quantity and impact of errors on emission inventory reliability,
a quality assurance procedure should be initiated each time an Inventory
effort is conducted. Quality assurance/quality control techniques can be
applied throughout the Inventory program from planning to reporting to ensure
that potential errors are minimized. These techniques can be classified as
either preventive or corrective.'' Preventive techniques are those that are
applied as part of the inventory planning procedures. Some common preventive
techniques, e.g., classroom instruction for personnel and the establishment of
a specific emission inventory reference library, are shown in Table 5-3. Many
of these techniques are already an integral part of most inventory processes.
Others can be easily incorporated with few changes in normal agency procedures.
5-9
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Corrective techniques are those that are implemented to detect errors
that cannot be eliminated by preventive measures. The data validation and
edit procedures previously mentioned are examples of corrective action control
techniques. Some of these techniques, listed in Table 5-4, reduce random
errors such as digit transposition. Another purpose, however, is to detect
deficiencies in the emission Inventory process. The techniques can provide
useful feedback to the task planners and can provide a basis for improving the
preventive control techniques. It is imperative that all errors, whether
detected by techniques such as these shown in Table 5-4 or by users, source
inspectors or other agency personnel, be documented in writing. Standard
corrective action forms must be used and mechanisms provided to ensure that
the corrective actions are instituted and effective.'
The appointment of one individual to act as quality assurance coordinator
will help to ensure that all control techniques will be implemented once they
are identified. The coordinator can independently audit the emission
inventory process to ensure that errors in all phases of preparing the
inventory are detected and corrected. This individual will serve as the focal
point for all quality assurance problems and corrective actions. The
development of an effective quality assurance program rests upon a sound
assessment of system procedures and data quality, identification of potential
sources of error, and the development of techniques for detecting errors as
well as controlling them.
5.5 EMISSION INVENTORY MAINTENANCE AND UPDATE
The compilation of an emissions inventory is a continual process. The
inventory organization must monitor and record changes in the total number of
sources as well as changes in the operation of existing sources. Maintenance
and updating of the inventory ensures that users are applying the most recent
data and can have confidence in the information provided. In addition,
recently promulgated Federal programs, such as Reasonable Further Progress
requirements discussed in Chapter 3, require that inventories be upgraded
annually and total emissions calculated to demonstrate progress toward meeting
national ambient air quality levele.
The need for periodic inventory maintenance and update is attributable to
several causes. During the period of a year, some facilities will deactivate
process equipment or close completely. New facilities and processes at
existing facilities will come online. Existing plants may also increase or
decrease their production schedules or modify product lines and virtually all
facilities must revise their fuel use and process throughput data as these
figures change annually. Population and land use changes that effect area and
mobile source pollutant emissions will also require inventory updating.
Updated regulations and emission factors may indicate the need for further
changes in the data file.
The mechanism for carrying out maintenance and update efforts vary among
inventory systems. Emission inventories that are maintained manually, with
only a paper record kept of all data, need only have specific data items
changed. Care should be taken with these systems, however, to preserve the
5-14
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modified or updated information for reference purposes. Computerized systems
vary in the ease with which data can be modified, but are updated in
essentially the same manner. The new or revised data are placed on
standardized computer forms and inserted into the file. A computer program
then transposes this new data onto the existing source record. If the
computerized inventory system has no mechanism for storing modified or deleted
information, it is recommended that tape records or a paper copy of all
historical source data be maintained at the agency, again for purposes of
reference.
References for Chapter 5.0
1» Procedures for Emission Inventory Preparation - Volume lit Point
Sources, EPA-450/4-81-026b, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1981.
2» Procedures for Emission Inventory Preparation - Volume III: Area Sources,
EPA-450/4-81-026c, U.S. Environmental Protection Agency, Research
Triangle Park, NC, September 1981.
3. Procedures for Emission Inventory Preparation - Volume IV; Mobile
Sources, EPA-450/4-81-026d, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1981.
4. Development of Questionnaires for Various Emission Inventory Uses,
EPA-450/2-78-122, U.S. Environmental Protection Agency, Research Triangle
Park, NC, March 1979.
5. Guide for Compiling a Comprehensive Emission Inventory (revised),
APTD-1135, U.S. Environmental Protection Agency, Research Triangle Park,
NC, December 1978.
6. Compilation of Air Pollution Emission Factors, AP-42, U.S. Environmental
Protection Agency, Research Triergle Park, NC, December 1980.
7. Development of an Emission Inventory Quality Assurance Manual,
EPA-450/4-79-006, U.S. Environmental Protection Agency, Research Triangle
Park, NC, December 1978.
5-16
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6.0 PRESENTATION OF INVENTORIES/DATA SYSTEMS
The diversity of applications for which an emission inventory can be used
has resulted in a variety of methods for data presentation- Specific display
methods are dependent upon many factors including the type and amount of data
required, the purpose of the data summary, and the audience to which the
summary is directed.
The basic "unit" of emission inventory data is the individual source
record. Typical source records are presented on Figure 6-1, for the
Federally-sponsored Emission Inventory System-'- (EIS) and Figure 6-2 for a
computerized state inventory system (New York AIR-100). These source records
contain all relevant source and emission point identifiers. Complete emission
inventory reports, containing one such record for each emission point, are
typically used by state and local agencies in their source-oriented
activities, such as enforcement inspections and plan reviews. For other
studies, source data summaries, focusing on one or more source identifiers,
can be compiled. These identifiers can generally be placed into the following
four categories:
1. Source Category
All facilities
- Individual emission points
- SIC (common industry)
- SCC (common process)
- Area sources
- Mobile sources
- Fugitive sources
2. Geographical Category
- National
State
- County
AQCR
AQMA
- Other (defined for specific projects)
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3. Pollutant Category
- Individual criteria pollutants
All criteria pollutants
Special (NESHAPS, Reactive VOC, etc.)
4. Other
- Energy use (by fuel)
- Control device application
Data summaries are usually compiled relating these Identifiers. For
example, lists may detail the major particulate-emltting facilities within an
AQCR; all facilities within a state that use asbestos and have an SIC code of
3293 (gaskets, packing, and sealing devices); or all facilities that consume
more than 100,000 tons of bituminous coal per year. Once the specific data
requirements of a project are defined and the appropriate data summaries are
obtained from an. agency's emission inventory, the data must be presented in an
appropriate format. The following subsection Illustrates various presentation
techniques. Many of the examples shown are taken from EPA reports and reflect
national emissions; however, the techniques shown are useful to the reporting
aspects of state and local air pollution problems.
6.1 PRESENTATION TECHNIQUES
The most common method of presenting emission Inventory data is the
tabulated summary. Figures 6-3 through 6-5 present examples of this display
technique. A second major presentation technique is the pie chart. This
method, like all graphical displays, Is often useful when presenting data to
those who do not have the time and/or expertise to interpret detailed tabular
summaries. Figures 6-6 and 6-7 are twj examples of pie charts used to present
emission Information. Pie charts present component data as a percentage of
the whole and, therefore, are useful for representing the relative
contribution of various emission source categories In a given area. Figure
6-6, for example, presents the relative contribution of each of the major
pollutants to total criteria air pollutant emissions in the United States.
Sulfur oxides and nitrogen oxides are singled out in this chart, as these data
were used in a presentation concerning the acid rain problem. Figure 6-7
presents the relative contribution of various categories to total volatile
organic compound (VOC) emissions.^ Without describing actual emission
levels, this chart identifies the major source categories (bulk petroleum
storage and degreasing) and their contribution to total emissions. Pie charts
simplify the comparison of emission data from various sources by concisely
summarizing large amounts of Information that may occupy several pages of
tables in a report.
The time series of chart represents another graphical display technique,
Figures 6-8 and 6-9. These charts displays changes over time of one or
several components, and are often used In emission trend reports. Knowledge
6-4
-------
Source category
Transportation
Highway vehicles
Non-highway vehicles
Stationary fuel combustion
Electric utilities
Industrial
Residential, commercial, and institutional
Industrial processes
Chemicals
Petroleum refining
Metals
Mineral products
Oil and gas production and marketing
Industrial organic solvent use
Other processes
Solid waste
Miscellaneous
Forest wildfires and managed burning
Agricultural burning
Coal refuse burning
Structural fires
Miscellaneous organic solvent use
Total
TSP
1.1
0.8
0.3
4.8
3.4
1.2
0.2
5.4
0.2
0.1
1.3
2.7
0
0
1.1
0.4
0.7
0.5
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0.4
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27.4
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4.9
4.3
0.5
0
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0
102.7
Note: A zero indicates emissions of less than 50,000 metric tons per year.
Figure 6-3. Nationwide emission estimates, 1977 (10
metric tons/year).
6-5
-------
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CARBON MONOXIDE
53%
SUSPENDED
PARTICLES
6%
Matin* Air Qutftty. Monitoring, and Emtacfon Trancte ftopon. 1977,
US EPA, December 1078.
Figure 6-6. Air emissions of pollutants in the United States.
6-8
-------
DECREASING
13.2%
GASOLINE
MARKETING
11.5%
SURFACE COATINGS
40.1%' /
/
DRY CLEANING
3.6%
MANUFACTURING
2.2%
FUEL COMB.
3.5%
TRADE
PAINTS
5.0%
PRINTING
5.1%
BULK PETROLEUM
STORAGE 22.1%
AIRCRAFT, RAILROADS,
VESSELS, INCINERA-
TION 3.9%
INDUSTRIAL
"PAINTS"
11.4%
FABRIC/RUBBER
6.2%
(Note: Highway vehicles are excluded)
Source: Reference 4.
Figure 6-7. An example of pie chart displaying the distribution
of VOC emissions in a survey area.
6-9
-------
Monthly
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1973
1974
1975
1976
1977
1978
1979
*Btu consumption for all sectors is cumulated to create total
Figure 6-8. Energy consumption by economic sector.
6-10
-------
1,000,000
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-------
of emission variations will aid regulatory personnel in such activities as
planning the operation of air quality monitoring stations; scheduling
enforcement activities; and establishing air quality management priorities,
based on historical or, as in Figure 6-9, projected emission estimates.
Bar charts, Figures 6-10 and 6-11, are another common method of
presenting emission data. Like the other graphical methods, they provide
visible comparisons of emission magnitudes. When used to present historical
trends of multiple sources, as in Figures 6-10, the bar chart clearly shows
the trend in overall emissions as well the trend in emissions from individual
components, particularly those of major contributors. Figure 6-11 shows how
the same set of data can be presented in two separate ways using bar charts.
The amount and type of fuel used by the major consumer categories are
presented and certain dependencies are easily distinguished, such as the use
of petroleum in the transportation sector.
Another graphical technique that is useful for the presentation of air
quality data is the emission density map, as shown in Figures 6-12, 6-13 and
6-14. These emission density presentations identify the spatial distribution
of emissions. They clearly indicate specific areas of concern, and have been
used by agencies to present justification for adaptation of area specific
emission regulations.
The tabular and graphical display techniques shown in this section do not
represent the only methods of presenting emission inventory data. The
specific purpose of the summary, the source indicators that are to be
summarized, the data reporting capabilities of the data system, and the
environmental awareness of the audience must be considered before specific
techniques are selected and used by the agency.
6.2 SUMMARY OF INVENTORY DATA SYSTEMS
Emission inventory systems of varying complexity are presently installed
at all state and most local air pollution control agencies. The complexity
and sophistication of the systems used by state or local agencies reflect many
factors, including the number and type of emission sources within the state
and the technical and financial resources available to the agency. While EPA
has specific emission inventory reporting requirements, the manner in which
data are stored and handled is left to the individual state agencies. Several
methods of handling emission inventory data have evolved, based on special
in-house data requirements.
Currently (circa 1980), about 20 state agencies use the Comprehensive
Data Handling System (CDHS) to manage their emission inventory data. The
software for CDHS is provided by EPA to the state/local control agencies for
installation on their own computers. The system is designed to assist the
agency in meeting EPA reporting requirements and all software and updates to
the system are provided by EPA's National Air Data Branch (NADB). CDHS
consists of the following subsystems:
6-12
-------
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6-13
-------
Quadrillion (1015> Btu
4.0
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Gas
(Dry!
Petroleum
Hydro
Electric
Nuclear
Other
Plus Net
Coke Imports
Coal, Net Coke Imports, and Other
Petroleum
Natural Gas (Dry)
Hydroelectric, Nuclear
Electricity Distributed and Losses
2.228
Residential
and
Commercial
Industrial
Transportation
Electric
Utilities
Figure 6-11. Energy consumption by fuel use and consumer category.
6-14
-------
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Figure 6-14. Location and emission rate of alJ plants emitting SO-
6-17
-------
AQDHS (Air Quality Data Handling Subsystem)—An air quality data base.
Prepares a data set for submission to EPA to automatically satisfy
agency reporting requirements.
EIS/AS and EIS/PS (Emission Inventory System/Area Sources and Emission
Inventory System/Point Sources)-'-»^—A data base describing sources
of pollution, levels of pollution, and descriptive data related to
permits or registrations.
Supports the agency functions of inspection, complaint
investigation, legal compliance, and source surveillance.
Prepares a data set for submission to EPA to automatically satisfy
agency reporting requirements.
EMS (Enforcement Management Subsystem)—A data base for use by state
and local agencies to control enforcement activities.
Prepares reports, including standardized letters which can be mailed
directly to sources.
A typical source printout for the EIS/PS subsystem was presented in Figure
6-1. EIS/PS information requirements are based largely on the NEDS system,
and Its format contains all source and emission details currently needed to
meet various planning and enforcement applications. EIS data can be converted
to the required NEDS format automatically, through use of a conversion
program, thereby minimizing manpower requirements. Once installed, EIS/PS is
extremely easy to use. EPA will provide assistance when a user encounters
problems and also provides training sessions for users of the system
throughout the country on a periodic basis.
Approximately 15 of the remaining state agencies utilize some form of
automated emission Inventory. These systems include the AIR-100 system used
in New York State, the IBM Mr Pollution Control Starter System currently used
in Connecticut and Nebraska, and the Illinois Total Air System. The general
source and emission data contained In these systems are essentially the same
as that for EIS/PS as can be seen by an examination of the AIR-100 printout
presented in Figure 6-2. Although there are potential benefits in developing
and using an emission inventory data system that is specifically designed for
the needs of an agency, it is generally recommended that EIS be adopted by the
states now operating without automated emission inventory systems because of
its ease of use, widespread acceptance, excellent retrieval capabilities, and
available support from EPA.
6-18
-------
References for Chapter 6.0
1. The Emissions Inventory System/Point Source User's Guide,
EOA-450/4-80-010, U.S. Environmental Protection Agency, Research Triangle
Park, NC, May 1980.
2. 1974 National Emissions Data System (NEDS) Fuel Use Report,
EPA-450/2-77-031, U.S. Environmental Protection Agency, Research Triangle
Park, NC, April 1978.
3. 1977 National Emissions Report, EPA-450/4-80-005, U.S. Environmental
Protection Agency, Research Triangle Park, NC, March 1980.
4. Procedures for the Preparation of Emission Inventories for Volatile
Organic Compounds, Volume I, Second Edition, EPA-450/2-77-028, U.S.
Environmental Protection Agency, Research Triangle Park, NC, March 1980.
5. Systems Study of Air Pollution From Municipal Incineration, APTD 1283,
U.S. Environmental Protection Agency, Research Triangle Park, NC, March
1970.
6. The Emission Inventory System/Area Source User's Guide, EPA-450/5-80-009,
U.S. Environmental Protection Agency, Research Triangle Park, NC, May
1980.
6-19
-------
7.0 MANPOWER/RESOURCE ALLOCATION MODEL
The Time Requirement Model (TREM) for conducting an emission inventory,
presented in this chapter, has been developed to assist the planners of the
inventory in estimating the manpower requirements needed to achieve the
objectives of the inventory. Time requirements, based largely on past
experience, are estimated for discrete activities that, in total, comprise the
full range of activities involved in preparing an emission inventory.
The time requirement Cor each defined activity is comprised of both a
linear and fixed component. The linear component is a function of the number
of sources, and assumes that the time required to perform the operations
comprising an activity (e.g., code a form as part of a defined data
compilation activity)remains the same throughout the inventory effort. The
fixed component is independent of the number of sources and represents the
time required; for example, to develop a coding form and/or to write programs
to edit and verify the coded data. The fixed time requirement will vary from
activity to activity, depending upon the definition of an activity and its
associated fixed components. In the example above, the writing of edit and
verification programs cou] d logically be classified as a separate activity-
distinct from coding; e.g., as part of a quality assurance activity.
Regardless of the classification of work elements within activities, the
general expression for the total time required to perform an activity is given
by the general expression
TT = Tf + nTa (7-1)
where
TT = Total time required to perform an activity
Tf = Fixed time associated with an activity
n = The number of operations required to complete an activity
(usually the number of sources or counties within the inventory area)
Ta = Time required to complete an operation within an activity
As an example of the use of Equation 7~1, consider the time involved in
preparation of a point source list. The establishment of an initial source
list requires that a large number of reference sources (see Chapter 5) must be
reviewed to prepare a complete listing of all point sources. A senior
engineer will be needed to organize and direct the literature search and to
contact facilities to determine if they should be included in the listing of
potential point sources. The senior engineer should understand industrial
processes within the jurisdiction which are likely to be point sources of
emissions. He will be assisted by a junior engineer who will review the
literature and identify the facilities and a technician to code and enter the
data into a mailing list file.
7-1
-------
The fixed time associated with such an activity (Tp) is estimated to be
24 hours of senior engineer time and 80 hours of junior engineer time for a
total of 104 hours; the time required to code and install the listing in the
file (Ta) is estimated to be 0.04 hour per source. If there are 1000 point
sources the time required (nTa) is 40 hours. Thus TT the total time
required initially to develop a point source listing is 144 hours.
TT = 104+ 1000 (0.04) - 144
The maintenance of the initial listing will require far less effort.
Estimates of the fixed time associated with an activity is 8 hours of senior
engineer and 20 hours of junior engineer time. The time required to code and
install new sources (or delete sources) is the same as for the initial effort
(0.04 hours per source), but the number of sources will generally be far less
than the initial number. If 100 sources are added to the point source listing
the total maintenance effort is
TT = 28 + 100 (0.04) = 32 hours.
The model expression, Equation 7-1, is presented graphically in Figure 7-1.
The time requirement for an activity will depend not only upon the number of
sources and counties to be inventoried, but will also depend upon the
following:
Level of detail required,
Skill of personnel,
Availability of data,
Status of existing inventory,
Status of existing data handling system,
Status of existing quality assurance program.
IO
z
UJ "~"
-(/>
* (E
UJ^
2:0
MAN-HOURS
ITEMS (SOURCES) TO BE PROCESSED
Figure 7-1. Time requirement model—graphical representation.
7-2
-------
The agency will be required to make some judgments concerning the above
factors and adjust the time requirements of the TREM as presented in this
chapter. When an agency has conducted inventories regularly, its past
experience can be used to estimate time requirements. If an agency desires
additional information concerning time and manpower requirements, information
can be found in the published literature.^>^>3 in addition, a computer
model is available from EPA which estimates technical and administrative costs
associated with preparing emission inventories. To obtain additional
information, contact an EPA Regional Office or the Control Programs Operations
Branch, Control Process and Development Division, MD-15, U.S. Environmental
Protection Agency, Research Triangle Park, NC, 27711.
The activities involved in developing the total inventory of point, area
and mobile sources are listed in Table 7-1, along with the results of the TREM
analysis for each activity. Each of these activities, referred to in the
model as a "task,", is discussed separately, specific assumptions defined, and
time requirements estimated for both an initial inventory (TTj) and an
inventory maintenance effort (TTj,j). Each task (activity) presentation is
formatted to provide the information listed below.
1. Task: Name of the task.
2. Task overview: A general overview of the activities included in the
task and any special instructions for interpreting and using the
included information.
3. Occupational category: The educational background of agency
personnel; e.g., senior or junior engineer or computer software
specialist.
A. Knowledge and skill requirements: Additional knowledge and
experience of personnel required to effectively perform the task.
5. Time requirements: TREM determined manpower requirements for both
the initial effort and the maintenance effort.
7-3
-------
TABLE 7-1. TIME REQUIREMENT MODEL (TREM) SUMMARY
Initial
effort T
(hours)
Maintenance
effort TTM
(hours)
Point Source Inventory
Establishment of a source list
Development of a questionnaire
Printing mailing list and labels
Mail questionnaires
Logging and review of returns
Assignment of codes
Data coding
Calculation of emissions
Quality assurance
Data presentation
Area Source Inventory
Data collection
Program compilation
Existing software
New software
Data coding
Software development
Existing software
New software
Calculation of emissions
Manual approach
Computerized approach
Quality assurance
Data presentation
Mobile Source Inventory
Establishment of liasons with other agencies
Data collection
Data coding
Software development
Existing software
New software
Calculation of emissions
Manual approach
Computerized approach
Quality assurance
Data presentation
104 + 0.04n
56
8 + 0.0005n
0.02n
8 + 0.2n
40 + O.ln
40 + 0.3n
40 + 0.5n
16 + 0.02n
40
80 + 0.25n
0.25 + O.OOln
40 + O.OOln
40 + 0.75n
80 + 0.2n
280 + 0.2n
40 + 8n
20 + 0.2n
20 + In
80
120
80 + 0.25n
40 + 0.75n
80 + 0.2n
280 + 0.2n
40 + 8n
40 + O.ln
20 + In
80
28 + 0.04n
16
1 + O.OOOSn
0.02n
0.2n
O.ln
0.2n
0.3n
16 + 0.02n
40
0.25n
0.25 + O.OOln
0.25 + O.OOln
0.75n
0.2n
8 + 0.2n
20 + 6n
20 + 0.2n
20 + In
80
120
0.25n
0.75n
0.2n
8 + 0.2n
20 + 6n
8 + O.ln
20 + In
80
7-4
-------
TIME REQUIREMENT MODEL
BY ACTIVITY FOR POINT SOURCES
7-5
-------
TIME REQUIREMENT MODEL BY ACTIVITY: Point Sources
TASK: Establishment of a source list
TASK OVERVIEW:
OCCUPATIONAL CATEGORY:
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:(1)
The establishment of an intial source list is a
time-consuming task. A large number of references
(see Chapter 5) must be consulted and cross-checked to
ensure that all sources are included. Although the
number of sources in the listing can be limited by
judicious selection of a cutoff size for each source
category, based on an indicator such as employment, a
large initial effort is worthwhile. An expanded
listing will prove helpful in reducing the effort
required by the agency if, for example, the point
source emission level is lowered in future programs.
Accordingly, it is recommended that, in preparing the
point source list, a conservative estimate of
emissions vs. employment (or other indicator) be
adopted for preparation of the initial mailing list.
Plant names, addresses, telephone numbers and contacts
must be assembled, and, if possible, coded and
keypunched for further use.
A senior engineer to organize and direct the
literature search and contact facilities, when
necessary; a junior engineer to review the literature
and identify the facilities to be listed; a technician
to either code or photostat acquired data; and a
keypunch operator.
In addition to a knowledge of process emissions, a
knowledge of demographic data is important, along with
some statistical knowledge, in order to assess factors
that would identify the emission potential of a
company.
Initial effort
TTj
nT
T =
24 hr of senior engineer
+ 80 hr of junior engineer, 104 hr
1 hr/50 sources to photostat or code
+ 1 hr/50 sources to keypunch; 2 hr/
50 sources or 0.04 hr/source
n = number of sources
= 104 + 0.04n hr
7-6
-------
(2) Maintenance effort
TTM = Tf + nTa
Tf = 8 hr of senior engineer
+ 20 hr of junior engineer, 28 hr
Ta = 2 hr/100 sources, to photostat or code
necessary changes + 2 hr/100 sources
to keypunch, 4 hr/100 sources; 0.02
hr/source
n = number of sources
TTM = 28 + 0.04n hr
7-7
-------
TIME REQUIREMENT MODEL BY ACTIVITY: Point Sources
TASK: Development of a questionnaireCs)
TASK OVERVIEW:
OCCUPATIONAL CATEGORY:
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
This activity involves a one-time effort to create a
simple questionnaireCs) to gather all necessary source
data. Alternatively, standard questionnaires, such as
those described in Volume II,^ could be used. For
maintenance purposes, this activity requires the
development of a miniquestionnaire that includes such
data items as a fuel update and changes in process or
control equipment.
A senior engineer to develop the questions, a
principal engineer to review them, and a computer
specialist to assist in the formatting of the
questionnaire for subsequent computerization of the
data.
A knowledge of processes, air pollution technologies,
and source evaluation ability are essential.
(1)
Initial effort
TTj = Tf + nTa
(2)
In this activity n = 1 (one-time activity),
so this equation reduces to
= T
Based on the past experience of several
agencies, this time requirement involves:
5 days of senior engineer time;
1 day of principal engineer time; and
1 day of computer specialist time.
TTj = 7 days, or 56 hr
Maintenance effort
The time requirement for maintenance effort could
involve:
1 day of senior engineer time;
1/2 day of principal engineer/scientist time;
and
1/2 day of computer specialist time.
TTM = 2 days, or 16 hr
7-8
-------
TIME REQUIREMENT MODEL BY ACTIVITY: Point Sources
TASK: Printing mailing list and labels
TASK OVERVIEW: This activity involves a one-time software development
effort to create a mailing list and labels. For
maintenance purpose, it only requires the execution
and running of the developed program. The mailing
labels are preferably keyed by an ID and SIC number to
facilitate logging of returns.
OCCUPATIONAL CATEGORY: A junior programmer
KNOWLEDGE AND SKILL
REQUIREMENTS: A knowledge of either FORTRAN or COBOL computer
language is essential to carry out this activity. A
programmer should also be able to use available
computer software packages such as EASYTRIEVE, SPSS,
etc,
TIME REQUIREMENT: (1) Initial effort
TTT = Tf + nTa
Tf = 8 hr if FORTRAN is used,
6 hr if COBOL is used
Ta = 0.25 hr/500 labels, or
0.0005 hr/label
n = number of labels (sources)
TTj = 8 + 0.0005n
(2) Maintenance effort
TTM - Tf + nTa
Tf = 1 hr, considerably less than initial
effort since a software package has been
developed. A programmer must assemble the
previously developed program, use JCL (Job
Control Language) and create a source list
and mailing labels
Ta = 0.0005 hr/label; remains unchanged
n = number of labels (sources)
TTM = 1 + 0.0005n hr
7-9
-------
TIME REQUIREMENT MODEL BY ACTIVITY: Point Source
TASK:
TASK OVERVIEW:
Mail questionnaire
This is a very simple task. It involves attaching the
preprinted label to a questionnaire, placing the
questionnaire in an envelope and attaching a second
label, identical to the first, to the mailing
envelope, which is then mailed.
OCCUPATIONAL CATEGORY: A technician or member of the support services staff
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
None
The total time required for the initial effort and for
the maintenance effort is the same.
= TTM = Tf
nT
There is no Tf time associated with this task;
all effort is related to the number of
questionnaires being mailed.
TTZ = TTM = nTa
Ta = 1 rain per source, or 0.02 hr/ source
n = number of sources
TTr = TTM = 0.02n hr
7-10
-------
TIME REQUIREMENT MODEL BY ACTIVITY: Point Sources
TASK:
TASK OVERVIEW:
Logging and review of returns
Questionnaires will be logged in and reviewed once
they are received. The purpose of the review is to
ensure that all questions have been properly
answered. It does not involve an in-depth technical
Teview which will be done by personnel responsible
for data coding and emissions calculations.
OCCUPATIONAL CATEGORY: A junior engineer reviews incoming questionnaires and
a technician logs them in.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Some process knowledge, plus a general knowledge of
the geographic area, including familiarity with the
local industrial base.
(1) Initial effort
TTj = Tf + nTa
Tf = fixed time required to set up
techniques for logging and review
system, 8 hr
TN = 2 min for logging/source, and
10 min for review/source;
12 min, or
0.2 hr/source
n = number of sources
TTX = 8 + 0.2n hr
(2) Maintenance effort
TTM = Tf + nTa
Tf = 0, techniques have already been
determined and documented.
Ta = 0.02 hr/source, same as initial case
n = number of sources
TTM = 0.2n hr
7-11
-------
TIME REQUIREMENT MODEL BY ACTIVITY: Point Sources
TASK:
TASK OVERVIEW:
OCCUPATIONAL CATEGORY:
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Assignment of codes
This activity involves the study of a source and its
related processes to determine the most applicable
source classification codes (SCC). A senior engineer
must thouroughly familiarize himself with the SCC
coding system in order to assign the appropriate
code. At the same time, a junior engineer or
programmer assigns the necessary systems codes such as
plant identification, city, county, state codes, etc.
A senior engineer to assign SCC; a junior engineer or
programmer to assign system identification codes.
A knowledge of industrial processes is helpful for
assigning SCC codes. A general knowledge of data
recording techniques is essential for assigning
geographic and system indicator codes.
(1) Initial effort
TTI = Tf + nTa
Tf = 40 hr, for familiarization with
SCC designations.
Ta = 5 min to assign SCC codes per
source + 1 min to assign state, county,
city codes per source
= 6 min per source, or 0.1 hr per source
n = number of sources
TTj = 40 + O.ln hr
(2) Maintenance effort
TTM = Tf + nTa
Tf = 0, as the familiarization process
is assumed to be complete
Ta = identical to initial effort
= 0.1 hr/source
n = number of sources
TTM = O.ln hr
7-12
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TIME REQUIREMENT MODEL BY ACTIVITY: Point Sources
TASK:
TASK OVERVIEW:
Data coding
All source data must be coded and entered into a
computerized data handling system. Regardless of the
emission inventory system used (NEDS, EIS, individual
state system, etc.)* coding and keypunching of data
items is an essential processing step.
OCCUPATIONAL CATEGORY: A junior engineer/scientist, a keypunch operator.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
A Senior Engineer who knows the industries and
processes within the region will be required to ensure
that the all of the data entered into the file is
complete and technically correct. He will assist the
two junior engineers in dealing with uncertainties and
will recontact facilities as required. This operation
should be carried out in adherence to documented
procedures. Familiarity with the computer load sheet
formats (assumed available) and data codes employed by
agency for control devices, test procedures, etc. will
be necessary.
(1) Initial effort
TTI = Tf + nTa
Tf = time required to understand coding
forms and procedures, 40 hr
Ta = 15 min to code each source
+ 5 min to keypunch each source;
20 min per source or 0.3 hr/source
n = number of sources
TTX = 40 + 0.3n hr
(2) Maintenance effort
TTM = Tf + nTa
Tf = 0, this assumed trained personnel are
available
7-13
-------
extremely variable since the number of
keypunch cards to be modified may vary
from 1 to 6, depending upon the data to
be modified. An average maintenance
effort is 10 to 15 min/source, or 0.2
hr/source
n = number of sources
TTM = 0.2n hr
7-14
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TIME REQUIREMENT MODEL BY ACTIVITY: Point Sources
TASK: Calculation of emissions
TASK OVERVIEW:
This activity involves estimating emission rates from
various sources and source categories using either
AP-42 or other emission factors developed for the
industry. It is an engineering activity, requiring an
initial high expenditure of manpower. With time,
however, the activity becomes increasingly more
routine.
OCCUPATIONAL CATEGORY: A senior engineer, a junior engineer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
A knowledge of processes and controls, material
balance and dimension analysis are important.
Familiarity with conversion factors is also important.
(1) Initial effort
TTj = Tf + nTa
Tf = time required to develop an
understanding of AP-42, or similar
reference materials, 40 hr
Ta = 0.5 hr/source to calculate source
emission rates
n = number of sources
TTj = 40 + 0.5n hr
(2) Maintenance effort
TTM = Tf + nTa
Tf = 0, as the familiarization process is
assumed to be complete
Ta =0.3 hr/source; once the calculation
techniques are learned, the time
requirement is approximately 60 percent
of the initial effort.
n = number of sources
TTM = 0.3n hr
7-15
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TIME REQUIREMENT MODEL BY ACTIVITY: Point Sources
TASK:
TASK OVERVIEW:
Quality assurance*
The objective of this task is to ensure that all data
are complete and correct. There are visual checks and
edit program check procedures. This task involves
running previously developed QA programs.
OCCUPATIONAL CATEGORY: A senior programmer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
A knowledge of the use of program packages, and also
of FORTRAN or some other computer language.
Initial and maintenance efforts are always the same.
TTX = TTM = Tf + nTa
T£ = time required to set up and execute
programs, 16 hr
Ta = 1 rain/source, or 0.02 hr/source
n = number of sources
TTX = TTM = 16 + 0.02n hr
*This action only performs machine edits and validity checks on coded
information and is not the quality assurance that must be performed manually
by competent engineers responsible for data review and coding.
7-16
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TIME REQUIREMENT MODEL BY ACTIVITY: Point Sources
TASK: Data presentation
TASK OVERVIEW: Once all data on point sources have been assembled,
reports are generated which present these data in
predetermined formats.
OCCUPATIONAL CATEGORY: Senior engineer.
KNOWLEDGE AND SKILL
REQUIREMENTS: Good communication skills and knowledge of the data
requirements of an agency are important.
TIME REQUIREMENT: TTj; = TTM = Tf + nTfl
The generation of a specific report will
always require the same amount of time. This
time will vary, depending on the number of
sources in the inventory. It is estimated that,
on the average, this task will require 40 hr for
all reporting.
TTZ = TTM = 8 hr
7-17
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TIME REQUIREMENT MODEL
BY ACTIVITY FOR AREA SOURCES
7-18
-------
TIME REQUIREMENT MODEL BY ACTIVITY: Area Sources
TASK:
TASK OVERVIEW:
Data collection
Assuming that data needs have been identified, the
data collection activity begins. Data logging
activities for received data is included in this
activity.
OCCUPATIONAL CATEGORY: A senior engineer and a technician.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Communication skills and a knowledge of demographic
data.
(1) Initial effort
TTI = Tf + nTa
If = time required to identify data source
contacts and verify information or
obtain missing information by
telephone, 80 hr
TN = time required to compile and log in
data is 15 minutes or 0.25 hr/county
n = number of counties
TTj = 80+ 0.25n hr
(2) Management effort
TTM = TF TnTN
Tp = 0, techniques have been determined
and personnel are familiar with them
TN = 0.25 hr/source, same as initial case
TTM = 0.25n hr
7-19
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TIME REQUIREMENT MODEL BY ACTIVITY: Area Sources
TASK: Program compilation
TASK OVERVIEW:
The development of an area source inventory requires
compilation of previously developed programs.
OCCUPATIONAL CATEGORY: A senior programmer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
A knowledge of either FORTRAN or any assembly language
is essential.
(1) TTinitial - Tf + nTa
Tf = program setup time, 0.25 hr
Ta = time to run program, 0.001 hr/county
number of counties
a
n
0.25 + O.OOln hr
This is the time requirement if the language and
the system are the same as the original program.
If the language or the system is different, then
the following time estimate to modify and test
the software on the agency's system should be
used.
TTinitial - Tf + nTa
Tf = software setup and debugging time,
40 hr
Ta = time to execute program, 0.001
hr/county
n = number of counties
(3) TTM = Tf + nTa
The maintenance effort for either case (1) or (2)
above is the same, inasmuch as a system and a
language will have been chosen.
7-20
-------
Tf = setup time for the program, 0.25 hr
Ta = time to execute the program, 0.001
hr/county
n = number of counties
TTM = 0.25 + O.OOln hr
7-21
-------
TIME REQUIREMENT MODEL BY ACTIVITY: Area Sources
TASK:
TASK OVERVIEW:
Data coding
If a computerized system is used, it is necessary to
code data as required by the system, using a coding
form designed for the system. The coded data must be
keypunched.
OCCUPATIONAL CATEGORY: Junior engineer, a keypunch operator.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
A knowledge of coding and computer systems is helpful.
(1) Initial effort
TTI = Tf + nTa
Tf = 40 hr, a junior engineer is
required
Ta = 30 min to code each county
+ 15 min to keypunch each county; 45
min/county or 0.75 hr/county
n = number of counties
TTX = 40 + 0.75n hr
(2) Maintenance effort
TTM » T£ + nTa
Tf = 0, since the engineer is already
aware of the coding needs.
Ta = the same as initial effort, 0.75
hr/county
TTM
n = number of counties
0.75n hr
7-22
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TIME REQUIREMENT MODEL BY ACTIVITY: Area Sources
TASK:
TASK OVERVIEW:
Software development for apportioning data on a county
level (or grid level)
This activity is necessary if an area has many
counties, and area source data must be apportioned to
each. The activity can be broken down into (1)
developing software and (2) use of existing programs.
OCCUPATIONAL CATEGORY: A junior programmer, a senior programmer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
A knowledge of programming and SPSS, or similar
packages is essential.
(1) Developing software
(a) Initial effort
TTj = If + nTa
Tf = 280 hr, time required to
understand, set up, develop, and
compile a program
Ta = 0.2 hr/county
n = number of counties
TTj = 280 + 0.2n hr
(b) Maintenance effort
TTM - Tf + nTa
Tf = 8 hr, there is no need to develop
a program since this activity is
only involved with compiling
programs and executing them.
Ta = identical to that of the initial
effort, 0.2 hr/county
n = number of counties
TTM = 8 + 0.2n hr
7-23
-------
(2) Use of previously developed programs
(a) Initial effort
TTj = Tf + nTa
Tf = 80 hr, to understand, install
and compile existing programs
Ta = remains the same, 0.2 hr/county
n = number of counties
TTj; = 80 + 0.2n hr
(b) Maintenance effort
TTM = Tf + nTa
Tf = 0
Ta = remains the same, 0.2 hr/county
n = number of counties
TTM = 0.2n hr
7-24
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TIME REQUIREMENT MODEL BY ACTIVITY: Area Sources
TASK:
TASK OVERVIEW:
OCCUPATIONAL CATEGORY
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Calculation of emissions
Two ways to calculate emissions are (1) manually and
(2) computerized. If an agency uses a computer for
coding and apportioning data, it should use the
computer to calculate emissions. Emission factors can
be built into the program.
A junior engineer, senior engineer—Manual System
A junior programmer, senior programmer—Computerized
System
Use of emission factors and understanding of basic
programming, using standard packages.
(1) Manual approach
(a) Initial effort
TTI = Tf + nTa
Tf = 40 hr to understand the use of
AP-42 emission factors
Ta = 8 hr for calculating emissions
for all area source activities in
each county
n = number of counties
TTj = 40 + 8n hr
(b) Maintenance effort
TTM = Tf + nTa
Tf = 20 hr, as familiarity with the
use of emission factors will
decrease the time
Ta = 6 hr/county, since this task
becomes routine
n = number of counties
TTM = 20 + 6n hr
7-25
-------
(2) Computerized approach
= TTM = Tf + nTa
Initial and maintenance efforts are the same
since computer programs have been previously
developed. Execution, startup, compilation
and running time will be identical.
Tf = 20 hr
Ta = 0.2 hr/county
n = number of counties
TTL = TTM = 20 + 0.2n hr
7-26
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TIME REQUIREMENT MODEL BY ACTIVITY: Area Sources
TASK: Quality assurance
TASK OVERVIEW:
The objective of this task is to make sure all data
are correct. Spot checks of data, and edit check
programs can be used.
OCCUPATIONAL CATEGORY: A senior programmer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
A knowledge of program packages and how to use them is
necessary.
TTj = TTM = Tf + nTa
Initial and maintenance efforts will be the same.
Tj = 20 hr to understand, setup and execute
program
Ta = 1 hr/county
n = number of counties
TTX = TTM = 20 + In hr
7-27
-------
TIME REQUIREMENT MODEL BY ACTIVITY: Area Sources
TASK:
TASK OVERVIEW:
Data presentation
A report, which is a one-time effort, is generated
after all data are put together. This report
documents an area source emission inventory.
OCCUPATIONAL CATEGORY: Senior engineer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Good communication skills and an awareness of agency
data needs are important.
= TT
M
nT
Initial and maintenance efforts are the same.
Both are one-time efforts, which are essentially
unrelated to the number of counties in the area.
Tf = 80 hr. This is an estimate based on
average report lengths.
= TT
M
80 hr
7-28
-------
TIME REQUIREMENT MODEL
BY ACTIVITY FOR MOBILE SOURCES
7-29
-------
TIME REQUIREMENT MODEL BY ACTIVITY: Mobile Sources
TASK:
TASK OVERVIEW:
Establishment of liaisons with other agencies
The development of a mobile source inventory involves
some coordination with other agencies. Management in
the emission inventory agency should contact other
federal, state and local agencies and request their
support.
OCCUPATIONAL CATEGORY: A principal engineer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Good communication skills and the ability to work with
other agency personnel.
= TT
M
nT
Initial and maintenance efforts always remain the
same. This effort continues for the entire
process of developing and/or maintaining the
emission inventory.
Tf = 120 hr
Ta = 0, as this task is not related to the
number of counties included in the inventory
TTX = TTM = 120 hr
7-30
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TIME REQUIREMENT MODEL BY ACTIVITY: Mobile Sources
TASK: Data collection
TASK OVERVIEW:
This task involves contacting people and agencies to
obtain the required data. A log of data that are
requested and received should be maintained.
Verification of received data is also required.
OCCUPATIONAL CATEGORY: A junior engineer and a technician.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Communication skills and a knowledge of traffic data.
(1) Initial effort
TTX = Tf + riTa
Tf = 80 hr, the time to identify contacts
Ta = 0.25 hr/county, the time to request,
log and verify data
n = number of counties
TTj <= 80 -v 0.25n hr
(2) Maintenance effort
TTM = Tf + nTa
If is zero, while Tfl remains the same as
that for the initial effort.
TTM = 0.25n hr
7-31
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TIME REQUIREMENT MODEL BY ACTIVITY: Mobile Sources
TASK:
TASK OVERVIEW:
Data coding
Coding and keypunching data for the computer, or a
program (MOBIL1 or APRAC, etc.), to calculate
emissions for on-highway and off-highway sources;
coded data are keypunched.
OCCUPATIONAL CATEGORY: A junior programmer, a keypunch operator.
KNOWLEDGE AND SKILL
REQUIREMENTS:
Coding skills and an understanding of coding forms.
(1) Initial effort
TTI ~ Tf + nTa
Tf = 40 hr, junior programmer to review
and develop familiarity with
techniques
Ta = 30 min/county to code and 15 min/
county to keypunch; 45 min/county
or 0.75 hr/county
n = number of counties
TTj = 40 + 0.75 n hr
(2) Maintenance Effort
TTM = Tf + nTa
Tf is not necessary, since the junior
programmer has already established the
mechanism for coding data. Ta remains the
same as in the case of the initial effort.
Ta = 0.75 hr/county
n = number of counties
TTM = 0.75n hr
7-32
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TIME REQUIREMENT MODEL BY ACTIVITY: Mobile Sources
TASK:
TASK OVERVIEW:
Software development for apportioning data on a county
level (or grid level)
This activity can be broken down into two tasks: (l)
development of necesary software and (2) use of
previously developed programs.
OCCUPATIONAL CATEGORY: A senior programmer, a junior transportation
programmer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
A knowledge of transportation programming and skill in
the use of SPSS or similar packages is helpful.
(1) Developing software
(a) Initial effort
TTj = Tf + nTa
Tf = 280 hr, time for a programmer to
understand the data needs of an
agency and then develop a program
Ta = time required for each county
0.2 hr/county
n = number of counties
TTj = 280 + 0.2n hr
(b) Maintenance effort
TTM - Tf + nTa
Tf = 8 hr, the time to compile a
program, use a data set and
execute the programs
Ta = 0.2 hr/county; remains the same
n = number of counties
TTM = 8 + 0.2n hr
7-33
-------
(2) Use of previously developed programs
(a) Initial effort
TTI = Tf + nTa
Tf = 80 hr, the time to understand,
install, and test the programs on
the agency's computer system
Ta = computer time for each county,
0.2 hr/county; remains the same
n = number of counties
TTX = 80 + 0.2n hr
(b) Maintenance effort
TTM - Tf + nTa
Tf = 0, as the programs have been
compiled
Ta = same as for the initial effort,
0.2 hr/county
n = number of counties
TTM = 0.2n hr
7-34
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TIME REQUIREMENT MODEL BY ACTIVITY: Mobile Sources
TASK: Calculation of emissions
TASK OVERVIEW: There are two ways to calculate emissions: (1)
manually and (2) using a computer with MOBIL1, APRAC,
or some other program.
OCCUPATIONAL CATEGORY: A junior engineer, senior engineer—Manual
A junior programmer, senior programmer—Computerized
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Understanding and use of emission factors; also basic
programming skills using standard packages.
(1) Manual approach
(a) Initial effort
TTX = Tf + nTa
Tf = 40 hr, to understand all the
emission factors and use of
conversion factors
Ta = 8 hr/county, for calculating
emissions for on-highway and
off-highway sources
n = number of counties
TTZ = 40 + 8n hr
(b) Maintenance effort
TTM = Tf + nTa
Tf = 20 hr, activity has become
routine
Ta = 6 hr/county, less for the same
reason
n - number of counties
TTM = 20 + 6n hr
7-35
-------
(2) Computerized approach
(a) Initial effort
= Tf + nTa
Tf = 40 hr, the time required to
install a program on the system
and get it working
Ta = 0.1 hr/county
n = number of counties
TTj = 40 + O.ln hr
(b) Maintenance effort
TTM = Tf + nTa
Tf = 8 hr, time is reduced because
the program is already installed.
Ta = 0.1 hr/county; remains the same
n = number of counties
TTM = 8 + O.ln hr
7-36
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TIME REQUIREMENT MODEL BY ACTIVITY: Mobile Sources
TASK:
TASK OVERVIEW:
Quality assurance
The objective of this task is to make sure the quality
of the data is acceptable. Input data should be
either spot checked, or reviewed through edit check
programs.
OCCUPATIONAL CATEGORY: A senior programmer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Knowledge of edit program packages and their use.
Initial and maintenance efforts are the same.
TTX = TTM = Tf + nTa
Tf = 20 hr, the time to understand and set up
programs
Ta = 1 hr/county; to check input data and flag
errors
n = number of counties
TTj = TTM = 20 + In hr
7-37
-------
TIME REQUIREMENT MODEL BY ACTIVITY: Mobile Sources
TASK:
TASK OVERVIEW:
Data presentation
A report which is a one-time effort is generated after
all data are combined and emissions calculated. This
report documents the mobile source emission inventory.
OCCUPATIONAL CATEGORY: Senior engineer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Good writing skills and an understanding of agency
needs.
TTI " TTM =
nT
Tf = 80 hr,time required to write a summary
report, which is the same for initial and
maintenance efforts
Ta = 0, as the report is not dependent upon the
number of counties surveyed
TTj = TTM - 80 hr
7-38
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APPENDIX A
DEFINITIONS
This section provides definitions of terms employed by air pollution
control agencies in conducting emission inventories and related regulatory
functions. The terms presented in Appendix A provide a working basis
for consistency among local, state and Federal agencies.
The words and terms listed in Appendix A were collected from various
publications such as the Federal Register, EPA Documents and Manuals, State
Implementation Plans, and the Clean Air Act. The references served to
identify terminilogy used by Federal and State Governments in regulations
governing air pollution control and prevention.
A-l
-------
Term
ACTIVITY LEVEL
Definition
Rate relating the amount of fuel con-
sumed, quantity of product manufactured
in an industrial process, or some com-
parative measure.
Reference
EPA-450/2-78-026
ADEQUATELY WETTED Sufficiently mixed or coated with water
or an aqueous solution to prevent dust
emissions.
40 CFR 61.02
AFFECTED FACILITY With reference to a stationary source,
any apparatus to which a standard is
applicable.
40 CFR 60.2
AIR POLLUTANT
Any air pollution agent or combination
of such agents, including any physical,
chemical, biological, radioactive (in-
cluding source material, special nuclear
material, and byproduct material) sub-
stance or matter which is emitted into
or otherwise enters the ambient air.
Clean Air Act
Sec. 302(g)
AIR POLLUTION
REQUIREMENT
Any emission limitation, schedule or
timetable for compliance, or other re-
quirement, which is prescribed under
any Federal, state, or local law or
regulation, including the Act* (except
for any requirement prescribed under
section 119 (c) or (d), Section 110(a)
(2)(F)(v), or Section 303 of the Act),
and which limits stationary source
emissions resulting from combustion of
fuels (including a prohibition on, or
specification of, the use of any fuel
or any type, grade, or pollution char-
acteristic) .
40 CFR 55.02
AIR QUALITY
CONTROL REGION
(AQCR)
Designated by the Administrator pursu-
ant to Sec. 107 of the Clean Air Act,
for air quality planning purposes.
40 CFR 81
*Clean Air Act
A-2
-------
Term
ALLOWABLE
EMISSIONS
Definition
The emission rate calculated using the
maximum rated capacity of the source
(unless the source is subject to en-
forceable permit conditions which limit
the operating rate or hours of operation
or both) and the most stringent of the
following:
(i) Applicable standards as set forth
in 40 CFR Part 60 and Part 61 (NSPS,
NESHAPS),
(ii) The applicable State Implementa-
tion Plan emission limitation, or
(iii) The emission rate specified as
a permit condition.
Reference
40 CFR 51.23
ALTERNATIVE
METHOD
AMBIENT AIR
Any method of sampling and analyzing for
an air pollutant which is not a refer-
ence or equivalent method but which has
been demonstrated to the Administrator's*
satisfaction to, in specific cases, pro-
duce results adequate for his determina-
tion of compliance.
That portion of the atmosphere external
to buildings to which the general public
has access.
40 CFR 60.2
40 CFR 50.1
AREA SOURCE
Any small residential, governmental,
institutional, commercial, or industrial
fuel combusion operations; onsite solid
waste disposal facility; motor vehicles,
aircraft, vessels, or other transporta-
tion facilities; or other miscellaneous
sources such as those listed in Appendix
D of 40 CFR 51, and as identified
through inventory techniques similar to
those described in: "A Rapid Survey
Technique for Estimating Community Air
Pollution Emissions," Public Health
Service Publication No. 999-AP-29,
October 1966.
40 CFR 51.1
*Administrator of EPA.
A-3
-------
Term
Definition
Reference
AREA SOURCE
(cont.)
APPENDIX D LISTING
(i) Fuel combustion — stationary source: 40 CFR 51.1
Anthracite coal, bituminous coal,
distillate oil, residual oil, natural
gas, wood, process gas (industrial)
(ii) Process losses
(iii) Solid wate disposal:
Incineration, open burning, dumps
(iv) Transportation:
Motor vehicles (gasoline and diesel
powered), off-highway use, aircraft,
railroads, vessels, gasoline hand-
ling evaporative losses
(v) Miscellaneous sources:
Forest fires, structural fires, coal
refuse burning, agricultural burning
ASBESTOS
Actinolite, amosite, anthophyllite,
chrysotile, crocidolite, tremolite.
40 CFR 61.21
BASELINE
CONCENTRATION
That ambient concentration level which
exists at the time of the applicable
baseline date, minus any contribution
from major stationary sources and major
modifications on which construction com-
menced on or after January 6, 1975. The
baseline concentration shall include con-
tributions from:
(i) The actual emissions of other sources
in existence on the applicable baseline
date, except that contributions from such
existing sources to the extent that a
plan revision proposing less restrictive
requirements affects such sources was
submitted on or before the baseline date
and was pending action by the Administra-
tor on that date shall be determined from
the allowable emissions under the plan,
as revised; and
40 Part 51.24
A-4
-------
Term
Definition
Reference
(ii) The allowable emissions of major sta-
tionary sources and major modifications
which commenced construction before Janu-
ary 6, 1975, but were not in operation by
the applicable baseline date.
BASELINE DATE
For every part of an Air Quality Control
Region (AQCR) designated as unclassifi-
able or attainment under Section 107(d)
(1)(D) or (E) of the Act the date of the
first complete application after August
7, 1977 for a permit under this section
for any major stationary source or major
modification in any part of the AQCR.
40 CFR 51.24
BERYLLIUM
The element beryllium. Where weights or
concentrations are specified, such weights
or concentrations apply to beryllium only,
excluding the weight or concentration of
any associated elements.
40 CFR 61.81
BEST AVAILABLE
CONTROL
TECHNOLOGY
(BACT)
An emission limitation (including a vis-
ible emission standard) based on the
maximum degree of reduction for each pol-
lutant subject to regulation under the
Act which would be emitted from any pro-
posed major stationary source or major
modification which the permitting author-
ity, on a case-bv~case basis, taking into
account energy, environmental, and eco-
nomic impacts and other costs determines
is achievable for such source or modifi-
cation through application of production
processes or available methods, systems,
and techniques, including fuel cleaning
or treatment or innovative fuel combus-
tion techniques for control of such pol-
lutant. In no event shall application
of the best available control technology
result in emissions of any pollutant
which would exceed the emissions allowed
by any applicable standard under 40 CFR
Part 60 and Part 61. If the reviewing
agency determines that technological or
economic limitations on the application
of measurement methodology to a particu-
lar class of sources would make the
40 CFR 51.24
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Term
Definition
imposition of an emission standard infeas-
ible, it may instead prescribe a design,
equipment, work practice or operational
standard, or combination thereof, to re-
quire the application of best available
control technology. Such standard shall,
to the degree possible, set forth the
emission reduction achievable by imple-
mentation of such design, equipment, work
practice or operation and shall provide
for compliance by means which achieve
equivalent results.
Reference
CAPITAL
EXPENDITURE
An expenditure for a physical or opera-
tional change to an existing facility
which exceeds the product of the applic-
able "annual asset guideline repair allow-
ance percentage" specified in the latest
edition of Internal Revenue Service Pub-
lication 534 and the existing facility's
basis, as defined in section 1012 of the
Internal Revenue Code.
40 CFR 60.2
COAL
Coal or coal derivatives.
40 CFR 55.02
COMMENCE
As applied to construction of a major
stationary source or major modification
means that the owner or operator has all
necessary preconstruction approvals and
either has:
(i) Begun, or caused to begin, a contin-
uous program of physical onsite construc-
tion of the source to be completed within
a reasonable time; or
(ii) Entered into binding agreements or
contractual obligations, which cannot be
cancelled or modified without substantial
loss to the owner or operator, to under-
take a program of construction of the
source to be completed within a reason-
able time.
40 CFR 51.24
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Term
COMPLIANCE
SCHEDULE
Definition
The date or dates by which a source or
category of sources is required to com-
ply with specific emission limitations
contained in an implementation plan and
with any increments of progress toward
such compliance.
Reference
40 CFR 51.1
CONDENSATE Hydrocarbon liquid separated from natural
(OF HYDROCARBONS) gas which condenses due to changes in the
temperature and/or pressure and remains
liquid at standard conditions.
40 CFR 60.11
CONSTRUCTION
Fabrication, erection, or installation
of a stationary source.
40 CFR 61.02
CONTROL STRATEGY
A combination of measures designated to
achieve the aggregate reduction of emis-
sions necessary for attainment and main-
tenance of a national standard, including,
but not limited to, measures such as:
(1) Emission limitations
(2) Federal or State emission charges
or taxes or other economic incentives or
disincentives.
(3) Closing or relocation of residen-
tial, commercial, or industrial facilities,
(4) Changes in schedules or methods of
operation of commercial or industrial
facilities or transportation systems, in-
cluding, but not limited to, short-term
changes made in accordance with standby
plans.
(5) Periodic inspection and testing of
motor vehicle emission control systems,
at such time as the Administrator deter-
mines that such programs are feasible
and practicable.
(6) Emission control measures applic-
able to in-use motor vehicles, including,
but not limited to, measures such as man-
datory maintenance, installation of emis-
sion control devices, and conversion to
gaseous fuels.
40 CFR 51.1
A-7
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Term
Definition
Reference
CONTROL STRATEGY
(cont.)
(7) Measures to reduce motor vehicle
traffic, including, but not limited to,
measures such as commuter taxes, gasoline
rationing; parking restrictions, or stag-
gered working hours.
(8) Expansion or promotion of the use
of mass transportation facilities through
measures such as increases in the fre-
quency, convenience, and passenger-
carrying capacity of mass transporation
systems or providing for special bus
lanes on major streets and highways.
(9) Any land use or transportation
control measures not specifically delin-
eated herein.
(10) Any variation of, or alternative
to any measure delineated herein.
(11) Control or prohibition of a fuel
or fuel additive used in motor vehicles,
if such control or prohibition is neces-
sary to achieve a national primary or
secondary air quality standard and is
approved by the Administrator under
Section 211(c)(l)(C) of the Clean Air
Act,
40 CFR 51.1
CRANKCASE
EMISSIONS
Airborne substances emitted to the atmo-
sphere from any portion of the engine
crankcase ventilation or lubrication
systems,
40 CFR 85.002
CRITERIA
POLLUTANT
Any air pollutant for which national
primary and secondary ambient air quality
standards have been promulgated, in-
cluding: sulfur oxides, particulate
matter, carbon monoxide, ozone, hydro-
carbons, nitrogen dioxide, and lead.
Clean Air Act,
Sec. 109
40 CFR 50.5
40 CFR 50.6
40 CFR 50.7
40 CFR 50.8
40 CFR 50.9
40 CFR 50.10
40 CFR 50.11
40 CFR 50.12
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Term
EMERGENCY
RENOVATION
Definition
A renovation operation that results from
a sudden, unexpected event, and is not a
planned renovation. Operations necessi-
tated by nonroutine failures of equip-
ment are included.
Reference
40 CFR 61.21
EMISSION
The act of releasing or discharging air
pollutants into the ambient air from any
source.
40 CFR 51.328
EMISSION FACTOR
An estimate of the rate at which a pollu- AP-42
tant is released to the atmosphere as a
result of some activity, such as combus-
tion or industrial production, divided
by the level of that activity.
EMISSION UNIT
Any part of a stationary source which
emits or has the potential to emit any
pollutant regulated under the Clean Air
Act.
40 CFR 51.24
EQUIVALENT
METHOD
A method of sampling and analyzing the
ambient air for an air pollutant that
has been designated as an equivalent
method in accordance with this part; it
does not include a method for which an
equivalent method designation has been
cancelled in accordance with § 53.11 or
§ 53.16 of 40 CFR 53.
40 CFR 53.1
EXHAUST EMISSIONS Substances emitted to the atmosphere
from any opening downstream from the
exhaust port of a motor vehicle engine.
40 CFR 85.002
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Term
EXISTING SOURCE
Definition
Any stationary source other than a new
source.
Reference
Clean Air Act
Sec. Ill a(6)
FACILITY
An identifiable piece of process equip-
ment. A stationary source is composed
of one or more pollutant-emitting
facilities.
40 CFR 51.24
FLOATING ROOF
A storage vessel cover consisting of a 40 CFR 60.111
double deck, pontoon single deck, internal
floating cover or covered floating roof,
which rests upon and is supported by the
petroleum liquid being contained, and is
equipped with a closure seal or seals to
close the space between the roof edge and
the tank wall.
FOSSIL FUEL
Natural gas, petroleum, coal, and any
form of solid, liquid, or gaseous fuel
derived from such material for the pur-
pose of creating useful heat.
40 CFR 60.41a
FRIABLE ASBESTOS
MATERIAL
Any material that contains more than 1 40 CFR 61.21
percent asbestos by weight and that can be
crumbled, pulverized, or reduced to powder,
when dry, by hand pressure.
FUEL-BURNING
EQUIPMENT
Any furnace, boiler, apparatus, stack, and 40 CFR 51.328
all appurtenances thereto, used in the pro-
cess of burning fuel for the primary pur-
pose of producing heat or power by indirect
heat transfer.
FUEL EVAPORATIVE
EMISSIONS
Vaporized fuel emitted into the atmosphere 40 CFR 85.0021
from the fuel system of a motor vehicle.
FUGITIVE EMISSIONS Those emissions which do not pass through 40 CFR 51.24
a stack, chimney, vent, or other function-
ally equivalent opening.
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Term
Definition
Reference
GASOLINE
Any fuel sold in any state for use in
motor vehicles and motor vehicle engines.
and commonly or commercially known or
sold as gasoline.
(a) "Leaded gasoline" means gasoline
which is produced with the use of any
lead additive or which contains more
than 0.5 grams of lead per gallon or
more than .005 grams of phosphorus per
gallon.
(b) "Unleaded gasoline" means gaso-
line containing not more than .05 grams
of lead per gallon and not more than
.005 grams of phosphorus per gallon.
40 CFR 80.2
HAZARDOUS AIR
POLLUTANT
An air pollutant to which no ambient
air quality standard is applicable and
which in the judgment of the administra-
tor causes, or contributes to, air pollu-
tion which may reasonably be anticipated
to result in an increase in mortality or
an increase in serious irreversible, or
incapacitating reversible, illness.
Clean Air Act
Sec. 112 (a)(l)
HAZARDOUS AND
TRACE EMISSIONS
SYSTEM (HATREMS)
Data base system developed to calculate
and store emissions data for lead as well
as other possible future criteria pollu-
tants. HATREMS utilizes NEDS data includ-
ing emission factors, default multiplier
units, control efficiency multiplier.
EPA-450/2-78-038
HOT SOAK LOSS
Fuel evaporative emissions during the 1
hour hot soak period which begins imme-
diately after the engine is turned off.
40 CFR 85.002
HYDROCARBON
Any organic compound consisting predomi-
nantly of carbon and hydrogen.
40 CFR 60.111
INCREMENTS OF
PROGRESS
Steps toward compliance which will be
taken by a specific source, including:
(1) Date of submittal of the source's
final control plan to the appropriate air
pollution control agency;
40 CFR 51.1
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Terms
Definition Reference
(2) Date by which contracts for emis-
sion control systems or process modifica-
tions will be awarded; or date by which
orders will be issued for the purchase of
component parts to accomplish emission
control or process modification;
(3) Date of initiation of on-site con-
struction or installation of emission con-
trol equipment or process change;
(4) Date by which on-site construction
or installation of emission control equip-
ment or process modification is to be com-
pleted; and
(5) Date by which final compliance is
to be achieved.
INDIRECT SOURCE
Facility, building, structure or installa- Clean Air Act
tion, real property, road or highway which (42 U.S.C. 1857
attracts, or may attract, mobile sources of Seq) Sec. 110
pollution; i.e., parking lots, parking ga-
rages, facilities subject to any measure
for management of parking supply, including
regulation of existing off-street parking
but such term does not include new or
existing on-street parking.
INDIRECT SOURCE
A facility, building, structure, or in-
stallation which attracts or may attract
mobile source activity that results in
emissions of a pollutant for which there
is a national standard. Such indirect
sources include, but are not limited to:
(a) Highways and roads
(b) Parking facilities.
(c) Retail, commercial and industrial
facilities.
(d) Recreation, amusement, sports
and entertainment facilities.
(e) Airports.
(f) Office and Government buildings.
(g) Apartment and condominium
buildings.
(h) Education facilities.
40 CFR 52.22
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Terms
Definition
Reference
INNOVATIVE
CONTROL
TECHNOLOGY
Any system of air pollution control that
has not been adequately demonstrated in
practice, but would have a substantial
likelihood of achieving greater continu-
ous emission reduction than any control
system in current practice or of achiev-
ing at least comparable reductions at
lower cost in terms of energy, economics,
or nonair quality environmental impacts.
40 CFR 51.24
1SOKINETIC
SAMPLING
Sampling in which the linear velocity of
the gas entering the sampling nozzle is
equal to that of the undisturbed gas
stream at the sample point.
40 CFR 60.2
LOWEST ACHIEVABLE
EMISSION RATE
(LAER)
For any source, that rate of emission
based on the following, whichever is
more stringent:
(i) The most stringent emission limita-
tion which is contained in the implementa-
tion plan of the State for such class or
category of source, unless the owner or
operator of the proposed source demon-
strates that such limitations are not
achievable; or
(ii) The most stringent emission limita-
tion which is achieved in practice by such
class or category of source.
This term, applied to a modification,
means the lowest achievable emission rate
for the new or modified facilities within
the source. In no event shall the appli-
cation of this term permit a proposed new
or modified facility to emit any pollutant
in excess of the amount allowable under
applicable new source standards of
performance.
40 CFR 51.328
MAJOR MODIFICATION Any physical change in or change in the
method of operation of a major stationary
source, or series of contemporaneous phys-
ical changes in or changes in the method of
operation of a major stationary source, that
would result in a significant net increase
in that sources potential to emit the pollu-
tant for which the stationary source is major
(or that would make the stationary source
A-13
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Terms Definition Reference
major taking into account all accumulated
net increases in potential emissions occur-
ing at the source, including any initial
construction since August 7, 1977). The
term "major modification" serves as the
definition of "modification" or "modified"
when used in the Clean Air Act in reference
to a major stationary source.
(ii) A physical change shall not include
routine maintenance, repair and replacement.
(iii) A change in the method of operation,
unless previously limited by enforceable
permit conditions, shall not include:
(a) Use of an alternative fuel or raw
material by reason of an order under
sections 2(a) and (b) of the Energy Supply
and Environmental Coordination Act of 1974
(or any superseding legislation), a prohi-
bition under the Power Plant and Industrial
Fuel Use Act of 1978 (or any superseding
legislation), or by reason of a natural gas
curtailment plan pursuant to the Federal
Power Act;
(b) Use of an alternative fuel or raw
material, if prior to January 6, 1975, the
source was capable of accommodating such
fuel or material;
(c) Use of an alternative fuel by reason
of an order or rule under section 125 of
the Clean Air Act;
(d) Change in ownership of the stationary
source; or
(e) Use of refuse derived fuel generated
from municipal solid waste.
(iv) Changes are "contemporaneous" only
if reductions occur after a notice is filed
pursuant to paragraph (v)(4) and before
operation of the emission unit or units that
will result in emission increases. Also, to
be "contemporaneous" all of the emission re-
ductions must be completed and enforceable
under the state plan before operation of
the emission unit or units that will result
in any emission increase. Where the new
emission unit is a replacement for an emis-
sion unit that is being shut down in order
to provide the necessary reductions, the
reviewing authority may allow up to 180 days
for shakedown or the new emission unit be-
fore the existing emission unit is required
to cease operation.
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Term Definition Reference
(v) For a series of changes in a sta-
tionary source to satisfy the requirement
of "no net increase," all of the following
must be satisfied:
(a) All reductions and all increases
must be for the same pollutant;
(b) The sum of all decreases must be
greater than or equal to the sum of all
increases;
(c) On balance the air quality of the
affected area must not be adversely
impacted.
(vi) In performing the calculation in
paragraph (b)(2)(v) of this section to
determine whether the sum of all decreases
is greater than or equal to the sum of all
increases) the following rules shall apply:
(a) Subject to the following adjustments,
the size of an increase or decrease is de-
termined by the difference between the poten-
tial to emit of the change of emissions unit
before and after the change.
(b) If potential to emit for a changed
emission unit was initially higher than
allowable emissions, then no offset credit
may be taken for decreasing potential to
emit down to allowable emissions.
(c) The requirement of 40 CFR Part 51,
Appendix S, Sections IV. C. 2 and 4 shall
apply involving the amount of credit per-
missible for changing fuels and for replac-
ing one hydrocarbon compound with another
of lesser reactivity.
MAJOR STATIONARY (i) Any of the following stationary 40 CFR 51.24
SOURCE sources of air pollutants which emit, or
have the potential to emit, 100 tons per
year or more of any pollutant regulated
under the Clean Air Act (the "Act"):
Fossil fuel-fired steam electric plants of
more than 250 million British thermal units
per hour heat input, coal cleaning plants
(with thermal dryers), kraft pulp mills,
Portland cement plants, primary zinc smel-
ters, iron and steel mill plants, primary
aluminum ore reduction plants, primary
copper smelters, municipal incinerators
capable of charging more than 250 tons of
refuse per day, hydrofluoric, sulfuric,
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Terms
MALFUNCTION
Definition Reference
and nitric acid plants, petroleum refin-
eries, lime plants, phosphate rock pro-
cessing plants, coke oven batteries, sul-
fur recovery plants, carbon black plants
(furnace process), primary lead smelters,
fuel conversion plants, sintering plants,
secondary metal production plants, chemical
process plants, fossil-fuel boilers (or
combination thereof) totaling more than
250 million British thermal units per hour
heat input, petroleum storage and transfer
ore processing plants, glass fiber process-
ing plants, and charcoal production plants;
(ii) Notwithstanding the stationary source
sizes specified in paragraph (b)(l)(i) of
this section, any stationary source which
emits, or has the potential to emit, 250
tons per year or more of any air pollutant
regulated under the Act.
Any sudden and unavoidable failure of air 40 CFR 60.2
pollution control equipment or process to
operate in a normal or usual manner. Fail-
ures that are caused entirely or in part by
poor maintenance, careless operation, or any
other preventable upset condition or prevent-
able equipment breakdown shall not be consid-
ered malfunctions.
MERCURY
The element mercury, excluding associated 40 CFR 61.51
elements, and includes mercury in particu-
lates, vapors, aerosols, and compounds.
MOBILES SOURCES
Including: light-duty gasoline powered
vehicles; light-duty diesel powered
vehicles; light-duty and heavy-duty gas-
oline powered trucks; heavy-duty diesel
powered vehicles; gaseous fueled vehicles;
motorcycles; aircraft; locomotives; in-
board and outboard powered vessels; agri-
cultural equipment; heavy-duty construction
equipment; snow mobiles; small, general
utility engines.
Compilation of
Air Pollution
Emission Factors
(AP-42)
A-16
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Terms
Definition
Reference
MODEL YEAR
The manufacturer's annual production period
(as determined by the Administrator) which
includes January 1 or such calendar year:
provided, that if the manufacturer has no
annual production period, the term "model
year" shall mean the calendar year.
40 CFR 85.1021
MODIFICATION
Any physical change in, or change in method Clean Air Act
of operation of, a stationary source which Sec. lll(a)(4)
increases the amount of any air pollutant
emitted by such source or which results in
the emission of any air pollutant not pre-
viously emitted.
NATIONAL PRIMARY
AMBIENT AIR
QUALITY STANDARDS
Ambient air quality standards the attain-
ment and maintenance of which in the judg-
ment of the Administrator (of US EPA), based
on such criteria and allowing an adequate
margin of safety, are requisite to protect
the public health.
Clean Air Act
Sec. 109(b)(l)
NATIONAL SECONDARY A level of air quality the attainment and
AMBIENT AIR
QUALITY STANDARDS
maintenance of which in the judgment of the
Administrator, based on such criteria, is
is requisite to protect the public welfare
from any known or anticipated adverse effects
associated with the presence of such air
pollutant in the ambient air.
Clean Air Act
Sec. 109(b)(2)
NECESSARY
RECONSTRUCTION
APPROVALS OR
PERMITS
Those permits or approvals required under 40 CFR 51.24
Federal air quality control laws and regu-
lations and those air quality control laws
and regulations which are part of the ap-
plicable State Implementation Plan.
NEW SOURCE
Any stationary source, the construction
or modification of which is commenced
after the publication of regulations
prescribing a standard or performance
applicable to the source.
Clean Air Act
Sec. lll(a)(2)
NITROGEN OXIDES
All oxides of nitrogen except nitrous
oxide, as measured by test methods set
forth in this part.
40 CFR 60.2
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Terms
NON ATTAINMENT
AREA
Definition
Reference
Any air pollutant an area which is shown Clean Air Act
by monitored data or which is calculated Sec. 171(a)(2)(I)
by air quality modeling to exceed any (2)
National Ambient Air Quality Standard for
such pollutant.
OPACITY
A state which renders material partially
or wholly impervious to rays of light and
causes obstruction of an observer's view.
Env. Rpt. 125-0132
OPACITY
The fraction of a beam of light, expres-
sed in percent, which fails to penetrate
a plume of smoke.
40 CFR 86.077-2
OWNER OR OPERATOR
Any persons who owns, leases, operates, 40 CFR 51.1
controls, or supervises a facility, build-
ing, structure, or installation which di-
rectly or indirectly results or may result
in emissions of any air pollutant for which
a national standard is in effect.
PARTICULATE MATTER Any finely divided solid or liquid mater-
ial, other than uncombined water, as mea-
sured by the reference methods specified
under each applicable subpart, or an
equivalent or alternative method.
40 CFR 60.2
PERSON
An individual, corporation, partnership, Clean Air Act
association, state, municipality, politi- Sec. 302 (e)
cal subdivision of a state, and any agency,
department, or instrumentality of the
United States and any officer, agent, or
employee thereof.
PETROLEUM
The crude oil removed from the earth and
the oils derived from tar sands, shale,
and coal.
40 CFR 60.101
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Terms
PHOTOCHEMICAL
OXIDANTS
Definition
Reference
Products of atmospheric reactions involv- Env. Rpt. 31:2151
ing organic pollutants, nitrogen oxides
(NOX), oxygen, and sunlight. They consist
mostly of ozone, N02, and peroxyacylnitrates
and other peroxy compounds, and are formed
along with other photochemical products,
such as aldehydes, nitrous acid, nitric acid,
and formic acid. They originate mainly from
volatile organic and NOX emissions produced
by human activities. Photochemical oxidant
formation is a complex function of emissions
and meterological patterns.
POINT SOURCE
(1) For particulate matter, sulfur
oxides, carbon monoxide, hydrocarbons,
and nitrogen dioxide —
(i) Any stationary source the actual
emissions of which are in excess of 90.7
metric tons (100 tons) per year of the
pollutant in a region containing an area
whose 1970 "urban place" population, as
defined by the U.S. Bureau of the Census,
was equal to or greater than 1 million;
(ii) Any stationary source the actual
emissions of which are in excess of 22.7
metric tons (25 tons) per year of the
pollutant in a region containing an area
whose 1970 "urban place" population, as
defined by the U.S. Bureau of Census was
less than 1 million; or
(iii) Without regard to amount of emis-
sions, stationary sources such as those
listed in Appendix C of 40 CFR Part 51.
(2) For lead, any stationary source the
actaul emissions of which are in excess of
4.54 metric tons (5 tons) per year of lead
or lead compounds measured as elemental
lead.
APPENDIX C LISTING
CHEMICAL PROCESS INDUSTRIES
Adipic acid.
Ammonia.
Ammonium nitrate.
Carbon black.
Charcoal.
Chlorine.
Detergent and soap.
40 CFR 51.1
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Terms Definition Reference
Explosives (TNT and
Hydrofluoric acid.
Nitric acid.
Paint and varnish manufacturing.
Phosphoric acid.
Phthalic anhydride.
Plastics manufacturing.
Printing ink manufacturing.
Sodium carbonate.
Sulfuric acid.
Synthetic fibers.
Synthetic rubber.
Terephthalic acid.
FOOD AND AGRICULTURAL INDUSTRIES
Alfalfa dehydrating.
Ammonium nitrate.
Coffee roasting.
Cotton ginning.
Feed and grain.
Fermentation processes.
Fertilizers.
Fish meal processing.
Meat smoke houses.
Starch manufacturing.
Sugar cane processing.
METALLURGICAL INDUSTRIES
Primary metals industries:
Aluminum ore reduction.
Copper smelters.
Ferroalloy production.
Iron and steel mills.
Lead smelters.
Metallurgical coke manufacturing.
Zinc.
Secondary metals industries:
Aluminum operations.
Brass and bronze smelting.
Ferroalloys.
Gray iron foundries.
Lead smelting.
Magnesium smelting.
Steel foundries.
Zinc processes.
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Terms Definition Reference
MINERAL PRODUCTS INDUSTRIES
Asphalt roofing.
Asphaltic concrete batching.
Bricks and related clay refractories.
Calcium carbide.
Castable refractories.
Cement.
Ceramic and clay processes.
Clay and fly ash sintering.
Coal cleaning.
Concrete batching.
Fiberglass manufacturing.
Frit manufacturing.
Glass manufacturing.
Gypsum manufacturing.
Lime manufacturing.
Mineral wool manufacturing.
Paperboard manufacturing.
Perite manufacturing.
Phosphate rock preparation.
Rock, gravel, and sand quarrying and pro-
cessing.
PETROLEUM REFINING AND PETROCHEMICAL
OPERATIONS
WOOD PROCESSING
PETROLEUM STORAGE (Storage tanks and
bulk terminals)
MISCELLANEOUS
Fossil fuel steam electric powerplants.
Municipal or equivalent.incinerators.
Open burning dumps.
POTENTIAL TO The capability at maximum design capacity 40 CFR 51.24
EMIT to emit a pollutant after the application
of air pollution control equipment. An-
nual potential shall be based on the maxi-
mum annual rated capacity of the stationary
source assuming continuous year round oper-
ation. Enforceable permit conditions on
the type of materials combusted or processed
may be used in determining the annual poten-
tial. Secondary emissions do not count in
determining annual potential. Fugitive
emissions also do not count, except with
respect to the following stationary sources
and then only to the extent quantifiable:
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Terms
POTENTIAL TO
EMIT (cont.)
Definitions
(i) Coal cleaning plants
(ii) Kraft pulp mills
(iii) Portland cement plants
(iv) Primary zinc smelters
(v) Iron and steel mill plants
(vi) Primary aluminum ore reduction
plants
(vii) Primary copper smelters
(viii) Municipal incinerators
(ix) Hydrofluoric, sulfuric, or nitric
acid plants
(x) Petroleum refineries
(xi) Lime plants
(xii) Phosphate rock processing plants
(xiii) Coke oven batteries
(xiv) Sulfur recovery plants
(xv) Carbon black plants
(xvi) Primary lead smelters
(xvii) Fuel conversion plants
(xviii) Sintering plants
(xix) Secondary metal production
plants
(xx) Chemical process plants
(xxi) Fossil fuel-fired boilers
(xxii) Petroleum storage and transfer
units
(xxiii) Taconite ore processing plants
(xxiv) Glass fiber processing plants
(xxv) Charcoal production plants
(xxvi) Fossil fuel-fired steam electric
plants
(xxvii) Any other stationary source cate-
gory which, at the time of the applicability
determination, is being regulated under
Section 111 or 112 of the Clean Air Act.
Reference
PRIMARY STANDARD
A national primary ambient air quality
standard promulgated pursuant to Section
109 of the Clean Air Act.
(FED) 40 CFR 5.1.
PROPORTIONAL
SAMPLING
Sampling at a rate that produces a con-
stant ratio of sampling rate to stack gas
flow rate.
40 CFR 60.2
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Terms
Definition
Reference
REASONABLY
AVAILABLE
CONTROL
TECHNOLOGY
(RACT)
Devices, systems, process modifications, 40 CFR 51.1
or other apparatus or techniques, the
application of which will permit attain-
ment of the emission limitations set forth
in Appendix B to 40 CFR 51, provided that
Appendix B to 40 CFR 51 is not intended,
and shall not be construed, to require or
encourage State agencies to adopt such emis-
sion limitations without due consideration
of (1) the necessity of imposing such emis-
sion limitations in order to attain and
maintain a national standard, (2) the social
and economic impact of such emission limita-
tions, and (3) alternative means of providing
for attainment and maintenance of such
national standards.
RECONSTRUCTION
Will be presumed to have taken place
where the fixed capital cost of the new
components exceeds 50 percent of the
fixed capital cost of a comparable en-
tirely new stationary source. However,
any decision as to whether reconstruction
has occurred will be made in accordance
with the provisions of 40 CFR 60.15(l)-(3) .
A reconstructed stationary source will be
treated as a new stationary source for pur-
poses of this section, except that use of
an alternative fuel or raw material by rea-
son of an order in effect under Sections
2(a) and (b) of the Energy Supply and Envi-
ronmental Coordination Act of 1974 (or any
superseding legislation), by reason of a
natural gas curtailment plan in effect pur-
suant to the Federal Power Act, or by rea-
son of an order or rule under Section 125
of the Act, shall not be considered recon-
struction. In determining best available
control technology for a reconstructed
stationary source, the provisions of 40
CFR 60.15(f)(4) shall be taken into account
in assessing whether a standard of perform-
ance under 40 CFR Part 60 is applicable
to each stationary source.
40 CFR 51.24
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Terms
REFERENCE METHOD
Definition
A method of sampling and analyzing the
ambient air for an air pollutant that is
specified as a reference method in an
Appendix to Part 50 of 40 CFR 53, or a
method that has been designated as a
reference method in accordance with this
part; it does not include a method for
which a reference method designation has
been cancelled in accordance with § 53.11
or § 53.16 of 40 CFR 53.
Reference
40 CFR 53.1
REGION
(1) An air quality control region
designated by the Secretary of Health,
Education, and Welfare or the Administra-
tor, (2) any area designated by a State
agency as an air quality control region
and approved by the Administrator, or
(3) any area of a State not designated as
an air quality control region under sub-
paragraph (1) or (2) of this paragraph.
40 CFR 51.1
REGIONAL
LIMITATION
The requirement that a source which is 40 CFR 55
located in an air quality control region
in which a national primary ambient air
quality standard for an air pollutant is
being exceeded in that region, may not
emit such pollutant in amounts which ex-
ceed any emission limitation (and may not
violate any other requirement) which applies
to such source, under the applicable
implementation plan for such pollutant.
REID VAPOR
PRESSURE
The absolute vapor pressure of volatile
crude oil and volatile non-viscous petro-
leum liquids, except liquified petroleum
gases, as determined by ASTM-D-323-58 (re-
approved 1968).
40 CFR 60.111
ROADWAYS
Surfaces on which motor vehicles travel
including, but not limited to, highways,
roads, streets, parking areas, and
driveways.
40 CFR 61.21
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Terms Definition Reference
SECONDARY Emissions which occur or would occur as a 40 CFR 51.24
EMISSIONS result of the construction or operation
of a major stationary source or major mod-
ification, but do not necessarily come from
the major stationary source or major modi-
fication itself. For purposes of this sec-
tion, secondary emissions must be specific
and well defined, must be quantifiable, and
must impact the same general area as the
secondary source or modification which causes
the secondary emissions. Secondary emissions
may include but are not limited to:
(i) Emissions from ships or trains coming
to or from the stationary source or modifi-
cation; and
(ii) Emissions from any offsite support
source which would be constructed or would
not otherwise increase its emissions.
SECONDARY STANDARD A national secondary ambient air quality 40 CFR 51.1
standard promulgated pursuant to Section
109 of the Clean Air Act.
SMALL REFINERY A refinery: 40 CFR 80.2
(1) Which has a crude oil or bona fide
feed stock capacity of 50,000 barrels per
day or less, and
(2) Which is not owned or controlled by
any refiner with a total combined crude oil
or bona fide feed stcek capacity greater
than 137,500 barrels per day.
"Owned or controlled" means leased, operated,
controlled, supervised, or in ten percent or
greater part, owned.
Crude oil or bona fide feed stock capacity
means that crude oil or bona fide feed stock
capacity certified by the Department of
Energy, Office of Refining Operations.
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Terms
Definition
Reference
SOLID-DERIVED
FUEL
Any solid, liquid, or gaseous fuel derived 40 CFR 60.41a
from solid fuel for the purpose of creating
useful heat and includes, but is not limited
to, solvent refined coal, liquified coal,
and gasified coal.
SOURCE
Any structure, building, facility, equip- 40 CFR 51.24
ment, installation or operation (or com-
bination thereof) which is located on one or
more contiguous or adjacent properties and
which is owned or operated by the same per-
son (or by persons under common control).
SOURCE
CLASSIFICATION
CODES (SCC)
Code giving specific identification of
the source, and defining the units of
activity level, and emission factors re-
lated to point source activity levels.
Emissions may be calculated by multiplying
emission factor for each SCC and the
activity level.
EPA-450/2-78-026
STACK
Any chimney flue, conduit, or duct arranged 40 CFR 51.328
to conduct emissions to the ambient air.
STACK DIAMETER
The inside diameter of a round gas exit
at the point of emission; for non-circu-
lar exits, it is an equivalent diameter
calculated from the cross-section area
at the point of discharge.
Equivalent Diameter =/1.128 Area
APTD-1135
STACK HEIGHT
The vertical distance between the point
of emission and ground level.
APTD-1135
STACK EXHAUST
FLOW RATE
The total volume of exhaust gas released APTD-1135
at the operating temperature of the stack;
design or maximum exhast-gas volume.
STACK TEMPERATURE
The temperature of the exhaust stream at APTD-1135
the stack exit reported in degrees Fahren-
heit under normal operating conditions.
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Terms
Definition
Reference
STANDARD
CONDITIONS
STANDARD
INDUSTRIAL
CLASSIFICATION
(SIC)
A dry gas temperature of 70° Fahrenheit 40 CFR 51.328
and a gas pressure of 14.7 pounds per
square inch absolute, or 293° Kelvin and
a pressure of 101.3 kilopascale (29.92
inches of Hg). Note that other definitions
have been specified by EPA.
The classification of establishments by Standard
type of activity in which (it is) engaged; Industrial
for purposes of facilitating the collec-
tion, tabulation, presentation, and
analysis of data relating to establish-
ments. Classification of establishments
by industry on a two-digit, a three-digit,
or a four-digit basis.
Classification
Manual
STANDARD OF
PERFORMANCE
Requirement of continuous emission reduc-
tion, including any requirement relating
to the operation or maintenance of a
source to assure continuous emission
reduction.
Clean Air Act
Sec. 302 (1)
STATE
IMPLEMENTATION
PLAN (SIP)
The plan including the most recent revi-
sion thereof, which has been approved or
promulgated by the Administrator under
Section 110 of the Act (Clean Air Act),
and which implements the requirements of
Section 110.
40 CFR 65.02
STARTUP
The setting in operation of a stationary
source for any purpose.
40 CFR 61.02
STATIONARY SOURCE Any structure, building, facility or in-
stallation which emits or may emit any
air pollutant regulated under the Clean
Air Act.
40 CFR 51.24
STATIONARY SOURCE
FUEL OR EMISSION
LIMITATION
Any emission limitation, schedule or time- 40 CFR 55,02
table of compliance, or other requirement,
which is prescribed under the Clean Air
Act (other than Section 119, Section lll(b),
Section 112 or Section 303 of the Act) or
contained in any applicable implementation
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Terms
Definition
Reference
STATIONARY
SOURCE FUEL
OR EMISSION
LIMITATION
(cont.)
plan (other than a requirement imposed pur-
suant to Section 110(a)(2)(F)(v) of the Act),
and which limits, or is designed to limit,
stationary source emissions resulting from
combustion of fuels, including a prohibition
on, or specification of, the use of any fuel
of any type, grade or pollution characteristic.
STRUCTURE,
BUILDING,
FACILITY,
INSTALLATION
Any grouping of pollutant-emitting activi- 40 CFR 51.24
ties which are located on one or more con-
tiguous or adjacent properties and which
are owned or operated by the same person
(or by persons under common control).
SUBMERGED FILL
PIPE
Any fill pipe the discharge opening of
which is entirely submerged when the
liquid level is 6 inches (15 cm) above
the bottom of the tank; or when applied
to a tank which is loaded from the side,
means any fill pipe the discharge open-
ing of which is entirely submerged when
the liquid level is 18 inches (45 cm)
above the bottom of the tank.
40 CFR 51.328
TOTAL REDUCED
SULFUR
The sum of the sulfur compounds hydrogen
sulfide, methyl meroaptan, dimethyl sul-
fide, and dimethyl disulfide, that are
released during the kraft pulping opera-
tion and measured by Reference Method 16.
40 CFR 60.283
TRANSPORTATION
CONTROL MEASUR
Any measure, such as reducing vehcile use, 40 CFR 51.1
changing traffic flow patterns, decreas-
ing emissions from individual motor vehi-
cles, or altering existing modal split
patterns that is directed toward reducing
emissions of air pollutants from transpor-
tation sources.
TRUE VAPOR
PRESSURE
The equilibrium partial pressure exerted 40 CFR 60.111
by a petroleum liquid as determined in ac-
cordance with methods described in Ameri-
can Petroleum Institute Bulletin 2517,
Evaporation Loss from Floating Roof Tanks,
1962.
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Terms
UNIVERSAL
TRANSVERSE
MERCATOR (UTM)
SYSTEM
Definition
System designed by U.S. Army to provide
for the projection of square grid zones
with convenient measuring units.
Reference
APTD-1135
VAPOR RECOVERY
SYSTEM
A vapor gathering system capable of col-
lecting all hydrocarbon vapors and gases
discharged from the storage vessel and a
vapor disposal system capable of proces-
sing such hydrocarbon vapors and gases so
as to prevent their emission to the
atmosphere.
40 CFR 60.111
VARIANCE
VOLATILE ORGANIC
COMPOUNDS (VOC)
40 CFR 51.1 (y)
The temporary deferral of a final comp-
liance date for an individual source sub-
ject to an approved regulation, or a tem-
porary change to an approved regulation
as it applies to an individual source.
Any compound containing carbon and hydro- 40 CFR 51.328
gen or containing carbon and hydrogen in
combination with any other element which
has a vapor pressure of 1.5 pounds per
square inch absolute (77.6 mm.Hg) or
greater under actual storage conditions.
WELFARE
Referring to effects on (welfare) in-
cludes, but is not limited to, effects on
soil, water, crops, vegetation, manmade
materials, animals, wildlife, weather,
visibility, and climate, damage to and
deterioration of property, and hazards to
transportation, as well as effects on
economic values and on personal comfort
and well-being.
Clean Air Act
Sec. 302(h)
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VARIATION IN DEFINITIONS
A review of state air pollution regulations was performed to determine
whether variations to the common terminology listed in Appendix A were
present. It was apparent that many of the terms used by state air pollution
regulations were indeed the same as the Federal version.
A few terms that were used in state regulations, but not listed in Federal
texts are presented in Appendix A. In every set of State Regulations or Laws,
some section of the text was devoted to the definitions utilized in the parti-
culate document.
One of the more commonly occuring differences between Federal and state
definitions is the definition of a source or a facility. State agencies
typically refer to a facility as being comprised of one or more sources; the
latter referring to an identifiable piece of process equipment capable of
emitting one or more pollutants. Conversely, Federal regulations define
these two terms in the opposite manner; a source is comprised of one or more
facilities. In this case the source represents a plant, and facilities would
refer to specific emission points within the plant. Since this and similar
discrepancies in definitions has lead to ambiguous enforcement of regulations,
the EPA now requires that all SIP's for nonattainment areas adopt Federal
definitions in order to be approved.
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Terms
AIR POLLUTANT
Definition
Reference
Dust, fumes, mist, smoke, vapor, odor, District of
particulate matter, or any combination Columbia
thereof, except that such term shall not
include uncombined water in the atmosphere
unless it presents a safety hazard.
AIR POLLUTANT
Presence in the outdoor atmosphere of one Alaska, Alabama
or more air contaminants in quantities and
duration that tend to be injurious to human
health or welfare, animal or plant life or
property or would reasonably interfere with
the enjoyment of life or property.
AIR POLLUTION
SOURCE (PORTABLE)
Any source such as, but not limited to, Colorado
asphalt batch plants and aggregate crush-
ers which commonly and by usual practice
are moved from one site to another. A source
will not be considered portable if it re-
mains on one site for more than two years.
EXISTING SOURCE
Any source in operation or on which con- Alabama
struction has commenced on the date of
initial adoption of an applicable rule,
or regulation; except that any existing
source which has undergone modification
of an applicable rule or regulation, shall
be reclassified and considered a new source.
FACILITY
Machinery, equipment, structures or any Utah
part of accessories thereof, installed or
acquired for the primary purpose of con-
trolling or disposing of air pollution.
It does not include an air conditioner,
fan or other similar device for the com-
fort of personnel.
FACILITY
A unit or multiple units built, installed
or established to serve a particular
purpose.
Alaska
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Terms
MAJOR STATIONARY
SOURCE
Definition
Any stationary source or modification to a
stationary source which increases the
allowable emission rate of any air contam-
inant by an amount equal to or greater than
50 tons per year; 1000 pounds per day; or
100 pounds per hour; whichever is more
restrictive.
Reference
POINT SOURCE
Any mobile source, process source or
stationary source which is subject to
emission rate standards or other stan-
dards imposed by these (Conn.) regulations.
Connecticut
PROCESS
Any action, operation or treatment of District of
materials, including handling and stor- Columbia
age thereof, which may cause discharge of
an air contaminant, or contaminants into
the atmosphere, but excluding fuel burning.
PROCESS
Any stationary emission source other than
a fuel combustion emission source or an
incinerator.
Illinois
PROCESS OPERATION
Any chemical, industrial, or manufacturing Delaware
operation including, but not limited to,
heat transfer, fluid flow, evaporation,
humidification, absorption, extraction,
distillation, drying, mixing, classifica-
tion, sedimentation, decantation, filtra-
tion, crystallization, centrifugation,
disintegration and material handling.
PROCESS SOURCE
The last operation or process which pro- Arizona
duces an air contaminant resulting from
(i) the separation of the air contaminant
from the process material, or (ii) the
conversion of constituents of the process
material into air contaminants and which
is not an air pollution abatement operation.
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Terms
PROCESS SOURCE
Definition
Any operation, process, or activity ex-
cept (1) the burning of fuel for indirect
heating in which the products of combus-
tion do not come in contact with the pro-
cess material, (2) the burning of refuse,
and (3) the processing of salvageable
material by burning.
Reference
Connecticut
SOURCE OR FACILITY Any property, source, facility, building, Georgia
structure, location, or installation at,
from, or by reason of which emissions of
air contaminants are or may reasonably be
expected to be emitted into the atmosphere.
SOURCE OPERATION
Any manufacturing process or any identi-
fiable part thereof emitting an air con-
taminant into the outdoor atmosphere
through one or more stacks or chimney.
New Jersey
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REFERENCES
1. The Clean Air Act and Amendments.
2. Code of Federal Regulations (CFR). Title 40. Parts 50, 51, 55, 60
80, 81, 85. .
3. The Environmental Reporter. Sections 121, 125, 128.
4. Guide for Compiling a Comprehensive Emission Inventory, Report No.
APTD-1135 US EPA, Office of Air and Waste Management, Office of
Air Quality Planning and Standards.
5. Compilation of Air Pollutant Emission Factors, AP-42, and Supplements
1-8. US EPA, Office of Air and Waste Management, Office of Air Quality
Planning and Standards. April 1973.
6. Federal Register, 44FR J1924, September 5, 1979.
7. Supplementary Guidelines for Lead Implementation Plants, EPA-450/2-78-
038. US EPA, Office of Air, Noise, and Radiation, Office of Air
Quality Planning and Standards. August 1978.
8. AEROS Manual of Codes, EPA-450/2-76-005 (OAQPS No. 1.2-042) US EPA,
Offfice of Air and Waste Management. Office of Air Quality Planning
and Standards. April 1976.
9. Interim Guideline on Air Quality Models, OAQPS No. 1.2-080. US EPA,
Office of Air Quality Planning and Standards. October 1977.
10. 1974 National Emissions Report: National Emissions Data System of
the Aerometric and Emissions Reporting System, EPA-450/2-78-026.
US EPA, Office of Air, Noise, and Radiation; OAQPS. April 1978.
A-34
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-450/4-81-026a
4. TITLE AND SUBTITLE
Procedures for Emission Inventory Preparation
Volume I: Emission Inventory Fundamentals
5. REPORT DATE
September 1981
6. PERFORMING ORGANIZATION CODE
3. RECIPIENT'S ACCESSION NO.
7. AUTHOR(S)
Monitoring and Data Analysis Division
Office Of Air Quality Planning and Standards
8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
EPA Project Officer: A. A. MacQueen
16 ABSTRACT
Procedures are described for compiling the complete comprehensive emission
inventory of the criteria pollutants and pollutant sources. These procedures
described are for use in the air quality management programs of state and local
air pollution control agencies.
Basic emission inventory elements—planning, data collection, emission esti-
mates, inventory file formatting, reporting and maintenance—are described.
Prescribed methods are presented; optional methods are provided. The procedures
are presented in five (5) volumes:
Volume I, Emission Inventory Fundamentals
Volume II, Point Sources
Volume III, Area Sources
Volume IV, Mobile Sources
Volume V, Bibliography
b.IDENTIFIERS/OPEN ENDED TERMS
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Emission Inventory Planning
Inventory Fundamentals
Source Inventory
Emissions Source
Emissions Files Formatting
| Questionnaire
Air Quality Management
c. COSATI Held/Group
18 DISTRIBUTION STATEMENT
19 SECURITY CLASS (Tins Report I
20 SECURITY CLASS ("fhiTpage)
21. NO. OF PAGES
178
22. PRICE
EPA Form 2220 — 1 (Rev. 4 — 77) PREVIOUS EDITION is
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