United States Office of Air Quality EPA-450/2-77-028
Environmental Protection Planning and Standards Second Edition
A9encV Research Triangle Park NC 27711 September 1980
Procedures for the
Preparation of Emission
Inventories for Volatile
Organic Compounds
Volume I
Second Ed&on
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EPA-450/2-77-028
Second Edition
Procedures for the Preparation
of Emission Inventories
for Volatile Organic Compounds
Volume I
Second Edition
Monitoring and Data Analysis Division
Office of Air Quality Planning and Standards
C
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 1980
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This report 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 document has been reviewed by the Office of Air Quality Planning and
Standards, U.S. Environmental Protection Agency, and approved for publication.
Subject to clarification, the contents reflect current Agency thinking.
Publication No. EPA-450/2-77-028
Second Edition
ii
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ACKNOWLEDGMENT
Bill Lamason and Tom Lahre of EPA's Monitoring and Data Analysis
Division, OAQPS, Research Triangle Park, N.C., are principally respon-
sible for the technical revision of this document. The review comments
of others within EPA's Office of Air Quality Planning and Standards are
appreciated, including editorial assistance from Whitmel Joyner. Special
acknowledgment is extended to Edna Brooks for her diligence in typing
this document.
111
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TABLE OF CONTENTS
Section Page
1.0 INTRODUCTION 1-1
1.1 Purpose 1-1
1.2 Contents Of Volume I 1-2
2.0 VOC INVENTORY OVERVIEW AND PLANNING 2-1
2.1 Overview Of Inventory Procedures 2-1
2.2 General Planning Considerations 2-2
2.2.1 VOC Emission Inventory End Uses 2-4
2.2.2 Sources Of VOC Emissions 2-5
2.2.3 Emission Inventory Manpower Requirements 2-7
2.2.4 Geographical Area 2-7
2.2.5 Spatial Resolution 2-8
2.2.6 Base Year Selection 2-8
2.2.7 Temporal Resolution 2-8
2.2.8 Point/Area Source Distinctions 2-9
2.2.9 Data Collection Methods 2-10
2.2.10 Exclusion Of Nonreactive Compounds And
And Consideration Of Species Information 2-10
2.2.11 Emission Projections 2-11
2.2.12 Status Of Existing Inventory 2-13
2.2.13 Corresponding Nitrogen Oxides (NOX) Inventory ... 2-13
2.2.14 Data Handling 2-14
2.2.15 Quality Assurance 2-15
2.2.16 Documentation 2-18
2.2.17 Anticipated Use Of A Photochemical
Dispersion Model 2-18
2.2.18 Planning Review 2-19
3.0 POINT SOURCE DATA COLLECTION 3-1
3.1 Questionnaires (Mail Survey Approach) 3-2
3.1 3.1.1 Preparing The Mailing List 3-2
3.1.2 Limiting The Size Of The Mail Survey 3-4
3.1.3 Designing The Questionnaires 3-6
3.1.4 Mailing And Tracking Of The Questionnaires
And Logging Returns 3-8
3.1.5 Recontacting 3-10
3.2 Plant Inspections 3-11
3.3 Other Air Pollution Agency Files 3-12
3.4 Publications 3-12
3.5 Existing Inventories 3-13
4.0 AREA SOURCE DATA COLLECTION 4-1
4.1 Introduction 4-1
4.1.1 Area Source Inventory Structure And Emphasis .... 4-1
4.1.2 Source Activity Levels 4-3
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Section
4.1.3 Methods For Estimating Area Source Activity
Levels And Emissions 4-3
4.1.4 Contents Of Chapter 4 4-5
4.2 Gasoline Distribution Losses 4-6
4.2.1 Determining Gasoline Sales 4-6
4.2.2 Estimating Gasoline Distribution Emissions 4-9
4.2.2.1 Tank Truck Unloading (Stage I) 4-9
4.2.2.2 Vehicle Fueling And Underground
Tank Breathing 4-10
4.2.2.3 Losses From Gasoline Tank Trucks In
Transit 4-10
4.3 Stationary Source Solvent Evaporation 4-11
4.3.1 Dry Cleaning 4-11
4.3.2 Degreasing 4-13
4.3.2.1 Open Top And Conveyorized Degreasing ... 4-16
4.3.2.2 Cold Cleaning Degreasing 4-17
4.3.3 Surface Coating 4-18
4.3.3.1 Architectural Surface Coating 4-19
4.3.3.2 Automobile Refinishing 4-20
4.3.3.3 Other Small Industrial Surface
Coating 4-20
4.3.4 Graphic Arts 4-21
4.3.5 Cutback Asphalt Paving 4-22
4.3.6 Pesticide Application 4-23
4.3.7 Commercial/Consumer Solvent Use 4-24
4.4 Nonhighway Mobile Sources 4-25
4.4.1 Aircraft 4-26
4.4.2 Railroads 4-27
4.4.3 Vessels 4-28
4.4.4 Other Off-highway Fuel Use 4-32
4.4.4.1 Off-highway Motorcycles 4-32
4.4.4.2 Farm Equipment 4-32
4.4.4.3 Construction Equipment 4-33
4.4.4.4 Industrial Equipment 4-34
4.4.4.5 Lawn And Garden Equipment 4-35
4.5 Solid Waste Incineration 4-35
4.5.1 On Site Incineration 4-36
4.5.2 Open Burning 4-36
4.6 Small Stationary Source Fossil Fuel Use 4-37
4.6.1 Fuel Oil Combustion 4-38
4.6.2 Coal Combustion 4-40
4.6.3 Natural Gas And Liquified Petroleum
Gas Consumption 4-40
4.6.4 Other Fuels 4-42
4.7 Other Area Sources 4-42
4.7.1 Forest Fires 4-42
4.7.2 Slash Burning And Agricultural Field Burning .... 4-43
4.7.3 Structure Fires 4-43
4.7.4 Orchard Heaters 4-43
5.0 INVENTORY METHODS FOR HIGHWAY VEHICLES 5-1
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Section page
6.0 EMISSIONS CALCULATIONS 6-1
6.1 Source Test Data 6-1
6.2 Materials Balance 6-4
6.3 Emission Factors 6-5
6.4 Scaling Up The Inventory 6-10
6.5 Excluding Nonreactive VOC From Emission Totals 6-12
6.6 Seasonal Adjustment Of The Annual Inventory 6-15
6.6.1 Seasonal Changes In Activity Levels 6-16
6.6.2 Seasonal Changes In Temperature 6-16
6.6.3 Other Seasonal Adjustment Considerations 6-17
6.7 Emission Projections 6-18
6.7.1 Major Point Source Projections 6-19
6.7.2 Aggregate Point Source Projections 6-20
6.7.3 Area Source Projection Procedures 6-21
6.7.4 Projection Review And Documentation 6-25
7.0 SUPPORTING DOCUMENTATION AND REPORTING 7-1
• 7.1 Reporting Forms 7-1
7.2 Supporting Documentation 7-2
APPENDIX A - GLOSSARY OF IMPORTANT TERMS A-l
APPENDIX B - POINT SOURCE PROCESS EMISSION REPORTING FORMAT B-l
APPENDIX C - SUMMARY OF CONTROL TECHNIQUES GUIDELINES C-l
APPENDIX D - EXAMPLE QUESTIONNAIRES D-l
APPENDIX E - SUPPLEMENTRY INVENTORY DOCUMENTATION DATA DISPLAYS .. E-l
APPENDIX F - EPA EMISSIONS DATA SYSTEMS F-l
vii
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1.0 INTRODUCTION
1.1 PURPOSE
Ozone is photochemically produced in the atmosphere when volatile
organic compounds (VOC) are mixed with nitrogen oxides (NOX) in the presence
of sunlight. In order for an air pollution control agency to develop and
implement an effective ozone control strategy, information must be compiled
on the important sources of these precursor pollutants. This is the role of
the emission inventory—to tell the agency what types of sources are present
in an area, how much of each pollutant is emitted, and what types of pro-
cesses and control devices are employed at each plant. Ultimately, the
inventory is used in conjunction with an appropriate source/receptor model
to relate emissions of VOC and NOX to subsequent levels of ozone in the
ambient air.
This document provides guidance to those engaged in the planning of a
VOC emission inventory and to those charged with the actual inventory compi-
lation effort. It is published in two major volumes. Volume I is devoted
to presenting step by step procedures for compiling the basic VOC emission
inventory. In this context, "basic" refers to an inventory that provides
the type of data needed for the simplest photochemical ozone source/receptor
models, such as the Empirical Kinetic Modeling Approach (EKMA).1>2 Gener-
ally, the basic inventory will produce annual or seasonal emission estimates
of reactive VOC for relatively large areas. Spatial resolution in such an
inventory will be at the county or equivalent level. This volume outlines
the procedures that an agency should consider in compiling an emission
inventory when not anticipating use of a photochemical atmospheric simulation
model.
Volume II describes techniques for compiling inventories of hourly
emissions allocated to subcounty grids.3 Reactive VOC and NOX in such
inventories are allocated into various classes or species categories. Such
degree of detail is required so that the inventory can be input to various
photochemical atmospheric simulation models.
Volume I contains a set of general technical procedures rather than a
single prescriptive guideline for completing a VOC emission inventory.
Because users' needs may vary from area to area, and because certain tech-
niques may be applicable in some areas and not in others, no one prescrip-
tive methodology is recommended for use in all circumstances. Rather, a
number of optional techniques representing various levels of detail are
presented for compiling the inventory. In addition, advantages and disad-
vantages of these techniques are weighed to help the agency to decide what
level of detail will be sufficient to meet its needs and objectives and,
at the same time, what can be accomplished given the constraints on the
inventory compilation effort.
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This document is not intended to set forth the Environmental Protection
Agency's requirements for inventory development or inventory data submittals.
Moreover, this document does not prescribe what control measures should be
considered in a specific inventory effort such as Reasonable Available
Control Technology (RACT). Although these topics are mentioned in Volume I
for discussion and example purposes, the reader should consult the Environ-
mental Protection Agency's State Implementation Plan (SIP) regulations to
determine the specific emission inventory and control strategy requirements
applicable to particular programs.1*
1.2 CONTENTS OF VOLUME I
The major emphasis of this guideline is on the development of a VOC
emission inventory that is useful in various facets of an ozone control
program. Thus, when describing the planning and implementation of an
inventory, the bulk of the discussion herein centers on issues that relate
to developing a strategy for ozone control. The VOC inventory can, of
course, be useful to the agency in other areas, such as in programs dealing
with specific toxic organic chemicals. The procedures in this document
will be generally applicable to developing VOC emission inventories for use
in other program areas and also to developing inventories of other pollutants
than VOC, including NOX.
Volume I is divided into chapters that correspond to the major steps
necessary in the basic inventory effort. Chapter 2 discusses planning, an
important and often neglected aspect of inventory effort. Various planning
considerations are explored, and guidance is offered to the agency to help
it decide which inventory approach should ultimately be pursued, given the
resources it has available. Included in Chapter 2 is an overview of the
basic "how to" procedures presented in the remainder" of the document. A
generalized flowchart is presented which outlines the major activities
necessary in the basic emission inventory compilation effort.
Chapter 3 describes the various ways source and emissions data can be
collected on individual sources for use in the point source inventory.
Direct plant contacts of various types, including questionnaires and plant
visits, represent the preferred approach for data collection. Approaches
are also discussed involving publications and other information sources.
Chapter 4 describes procedures for making collective activity level
and emission estimates for those area sources generally too small or too
numerous to be considered individually in the point source inventory. Such
procedures include making field surveys of actual area source activity as
well as the use of surrogate indicators of area source activity such as
population and employment.
Chapter 6 discusses procedures for making emission estimates based on
the source data collected from the plant contacts, field surveys and question-
naires. Procedures for handling source test data and performing material
balances are described. The basic use of emission factors is reviewed,
including cases where adjustments can be made to reflect specific source
parameters and environmental conditions. Also presented are procedures for
"scaling up" the inventory to account for missing sources as well as for
1-2
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adjusting the VOC emissions to exclude nonreactive components. Finally,
seasonal adjustment of the inventory is discussed along with techniques for
projecting emission totals.
Chapter 7 discusses reporting, i.e., the presentation of inventory
information in various ways useful to the agency. Reporting can include
listings of the individual data items contained in the inventory files as
well as various kinds of summary manipulations.
Appendix A contains a glossary of important terms used in conjunction
with VOC emission inventories. These definitions may give persons not
familiar with VOC inventories a better understanding of this document and of
compiling such inventories in their areas. Appendix B provides a detailed
listing of point source process emission points. Appendix C contains summary
descriptions of the VOC sources for which EPA has or will establish control
techniques guideline (CTG).
Appendix D includes an example of a cover letter and questionnaire used
in mailing surveys for point source inventories. Appendix E provides a
number of examples of emission inventory documentation. Appendix F contains
summary descriptions of the NEDS and EIS/P&R inventory systems available
from EPA for general use.
Comments and suggestions regarding the general technical content of
this document should be brought to the attention of the Director, Monitoring
and Data Analysis Division, Office of Air Quality Planning and Standards,
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711.
The reader should note that no procedures are presented in Chapter 5
for compiling inventories of emissions from highway vehicles. Recommended
techniques are being developed and will be in future editions of this
document. In the meantime, for information on this subject, the reader
should contact EPA's Office of Transportation and Land Use Policy, ANR-443,
401 M Street SW, Washington, DC 20460.
References for Chapter 1.0
1. Uses, Limitations and Technical Basis of Procedures for Quantifying
Relationships Between Photochemical Oxidants and Precursors,
EPA-450/2-77-021a, U.S. Environmental Protection Agency, Research
Triangle Park, NC, November 1977.
2. User's Manual for Kinetics Model and Ozone Isopleth Plotting Package,
EPA-600/8-78-014a, U.S. Environmental Protection Agency, Research
Triangle Park, NC, July 1978.
3. Procedures for the Preparation of Emission Inventories for Volatile
Organic Compounds, Volume II, EPA-450/4-79-018, U.S. Environmental
Protection Agency, Research Triangle Park, NC, September 1979.
4. Emission Industry Requirements for 1982 Ozone State Implementation
Plans, Draft, EPA-450/4-80-016, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1980.
1-3
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2.0 VOC INVENTORY OVERVIEW AND PLANNING
2.1 OVERVIEW OF INVENTORY PROCEDURES
The next several chapters present the "how to" for compiling the basic
volatile organic compound emission inventory. Emphasis is given to method-
ologies that produce annual emission estimates of reactive VOC for broad
geographical areas and which can be resolved to the county level. Some
discussion is devoted to adjusting an annual inventory of VOC emissions to
reflect conditions during the ozone season, which is the time interval of
primary interest in photochemical ozone production.
Four basic steps are involved in the preparation of a VOC emission
inventory. The first is planning. The agency should define the need for
the VOC inventory as well as the constraints that limit the ability of the
agency to produce it. The various planning aspects discussed in the follow-
ing sections of this chapter should all be considered prior to initiation of
the actual data gathering phases of the inventory effort. All proposed
procedures and data sources should be documented at the outset and be sub-
jected to review by all potential users of the final inventory, including
the management and technical staff of the inventory agency.
The second basic step is 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. Much more detailed data
are collected and maintained on point sources.
The third basic step in the inventory compilation effort involves an
analysis of data collected and the development of emission estimates for
each source. Emissions will be determined individually for each point
source, whereas emissions will generally be determined collectively for each
area source category. Source test data, material balances, and emission
factors are all used to make these estimates. Adjustments are required to
exclude nonreactive VOC and to make the resulting emission totals repre-
sentative of the ozone season. A special adjustment called "scaling up" is
necessary in some cases to account for sources not covered in the point
source inventory. Estimates of projected emissions must also be made as
part of this step.
The fourth step is reporting. Basically, reporting involves presenting
the inventory data in a format that serves the agency in the development and
implementation of an ozone control program or other regulatory effort.
Depending on the capabilities of the inventory data handling system, many
kinds of reports can be developed that will be useful in numerous facets of
the agency's ozone control effort.
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Figure 2.1-1 provides a generalized flowchart outlining the major
elements and activities needed in the compilation of the basic VOC emission
inventory. Each of these activities is described in detail in the following
chapters, except for the various aspects of planning, which are discussed in
the following sections of this chapter.
2.2 GENERAL PLANNING CONSIDERATIONS
Before an agency initiates the actual compilation of the VOC emission
inventory, the agency's management and technical staff must carefully
evaluate what its specific inventory needs are with respect to ozone strategy
development and must define what objectives it expects the inventory to
meet. Further, once agency management and staff have determined what its
needs are, and what specific objectives they expect the VOC emission inven-
tory to meet in the agency control program, a number of considerations
should be made before actually initiating the inventory. These consider-
ations involve various requirements and constraints—technical, economic,
and legal—that must be accounted for during the planning stages of the
inventory effort. Depending on the agency's needs, the time and resources
expended in dealing with these various requirements and constraints will
vary. This chapter provides guidance to help agency management and tech-
nical staff decide how these various considerations can best be addressed
with available resources to design and complete the emission inventory.
During the planning step of the VOC emission inventory, the agency
should address a number of questions which occur in developing the inven-
tory. The following questions should have been answered prior to initiating
the collection phase of the inventory effort.
0 What are the end uses of the VOC emission inventory (i.e., State
Implementation Plan [SIP] submittal, community or constituency reports, air
quality research, etc.)?
0 Have the source categories been defined that will be included in
the inventory? Are these categories compatible with the source and emissions
information available? Are they detailed enough to facilitate the making
and reporting of control strategy projections and to readily define emissions
of nonreactive VOC?
0 What are the manpower and budget allocations required and available
for the inventory effort?
0 Has the geographical area been outlined that will be inventoried?
What level of spatial resolution is needed for the source/receptor model
that will be used? What are the smallest political jurisdictions within the
inventory area for which area source activity level information is readily
available?
° What inventory base year will be selected which is appropriate for
the inventory end use?
0 What sources will have seasonally varying emissions? Will the
inventory be seasonally adjusted? Will annual or daily emissions be compiled?
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SOURCE
RECEPTOR
MODEL
TEMPORAL
RESOLUTION
SPATIAL
RESOLUTION
STATUS
OF EXISTING
INVENTORY
SPECIES
DATA
OTHER
-TIME
-MANPOWER
-BUDGET
-ETC
DECIDE
ON
METHODS
OF
OBTAINING
DATA
MAIL
SURVEY
DESIGN AND ASSEMBLE
QUESTIONNAIRES
MAIL QUESTIONNAIRES
PARE
LING
T
MINE
NCY
ES
•V-
PREPARE
DATA
HANDLING
SYSTEMS
-LOGGING
-TIMETABLES
-MAILING
LABELS
FILING AND
ANALYSIS
PROCEDURES
1
REMAIL THOSE
RETURNED
DUE TO
INCORRECT
ADDRESS
SMALL
SOURCES
POINT
SOURCE
PROCEDURES
SOURCE
NO
LONGER
OPERATI
1
.._ 1 SOURCE
NO 1 <,.7f: „„
EMISSIONS TVPC
VG
1
\ WITHIN
i AREA
POINT
SOURCE
DEFINITION
REPORT EMISSIONS AND PROCESS
PARAMETERS IN DESIRED FORMAT
(eg NEDS FORMAT, CHARTS, TABLE 2 2-1,
OR OTHER)
| DETERMINE LEVEL OF ANALYSIS REQUIRED |
f MAJOR SOURCE
DETAILED ANALYSIS TO DETERMINE EMISSIONS
AND PROCESS PARAMETERS BY CATEGORY
RECONTACT FOR ADDITIONAL DATA
GENERALIZED ANALYSIS FOR EMISSIONS
AND GENERAL PROCESS PARAMETERS
POINT
SOURCE
INVENTORY
RECONTACT FOR ADDITIONAL DATA
AREA
SOURCE
PROCEDURES
IDENTIFY AREA I
SOURCE CATEGORIES I
WHICH CAUSE EMISSIONS]
IN THE AREA I
APPROXIMATE
PERCENT OF
TOTAL IN EACH
CATEGORY
PRIORITIZE
CATEGORIES
AND DETERMINE
LEVEL OF EFFORT
FOR EACH
DETERMINE
AREA/GRID SIZE
FOR WHICH EMISSIONS
WILL BE FOUND
DETERMINE DATA REQUIRED
TO ACHIEVE LEVEL OF
EFFORT/ACCURACY FOR
EACH CATEGORY WITHIN
TO BE CONSIDERED
DETERMINE IF DATA RECEIVED IS
ADEQUATE
YES
I' '
DETERMINE LIKELY SOURCE OF DATA REQUIRED
CONTACT REQUIRED | PUBLICATION REQUIRED
SPECIFIC
AGENCY OR
[ OBTAIN DESIRED PUBLICATION |-
\iumwVoi " i > [CONTACT & REQUEST DESIRED INFORMATION
I
L
RECEIVE AND LOG IN RESPONSES
GENERAL
SURVEY
PREPARE
MAILING
LIST
DESIGN AND
ASSEMBLE
QUESTIONNAIRES
PREPARE
DATA
HANDLING
SYSTEMS
-LOGGING
TIMETABLES
-MAILING
LABELS
-RESPONSE
FILING AND
ANALYSIS
PROCEDURES
_L
RECONTACT
NON RESPONDANTS
REMAIL THOSE
RETURNED DUE
TO INCORRECT
ADDRESS
MAIL
QUESTIONNAIRES
RE-EVALUATE PRIORITIZATION
OF CATEGORIES TO BE
CONSISTENT WITH DATA RECEIVED
REPORT EMISSIONS IN
DESIRED FORMAT FOR
EACH AREA/GRID
DATA ADEQUATE | MORE DATA REQUJRED
RE-EVALUATE GRID SIZE TO BE
CONSISTENT WITH DATA AVAILABLE
LEVEL OF EFFORT & ACCURACY
-X.
CALCULATE EMISSIONS FOR EACH GRID
OR FOR THE SMALLEST AREA FOR WHICH
DATA IS AVAILABLE WHICHEVER LARGER
JL
AREA
SOURCE
INVEMTORY
APPORTION THOSE EMISSIONS WHICH ARE
ON A GEOGRAPHICAL BASIS LARGER THAN
THE GRIDS INTO THE GRIDS
PLANNING
DATA GATHERING
REPORTING
Figure 2.1-1. Flow chart of VOC emission inventory compilation activities (Radian, 1977).
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0 Has the point source cutoff level been defined? Do a large number
of industrial/commercial solvent users exist whose emissions are below the
chosen point source cutoff level? How will the inventory be scaled up to
account for these sources? What area source procedures will be utilized?
0 How will source data be collected for point and area VOC emission
sources?
0 What procedures will be used to identify nonreactive VOC emissions
and exclude them from the inventory?
0 How will the agency project emissions? Will general growth
factors be used, or will facility-specific growth information be solicited
during the plant contacts? Will the procedures used for estimating projected
emissions be methodologically consistent with those in the base year? What
will be the projection period, including the end year and intermediate
years?
0 Can the existing inventory (including background data) be used as
a starting point for the update? Are important VOC sources omitted from the
existing data base?
0 Are all sources of NOX identified, including those noncombustion
industrial processes that do not emit any VOC?
0 What inventory data handling system will be utilized? Is it
compatabile with EPA's NEDS or EIS?
0 What quality assurance measures are to be applied to the emission
inventory?
0 What inventory documentation will be required?
0 Does the agency anticipate running a photochemical model using the
basic inventory as a starting point for a more resolved inventory? If so,
has Volume II1 been studied, so that the additional data needs and data
handling requirements are understood?
The subject of each of the above questions is discussed briefly in the
next sections.
2.2.1 VOC EMISSION INVENTORY END USES
The most basic consideration in inventory planning is the ultimate
use(s) of the emission inventory will be used for upon completion. The end
uses of an inventory fall into two general categories: (1) air quality
research and (2) air quality control strategy development.
An air quality research inventory could fulfill any number of data
requirements for studying the relationship between VOC emissions and ozone
concentrations in any given study area. Usually, inventory requirements are
determined only by the inventory agency's study needs. Thus, most research
2-4
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inventories are unrestricted, allowing the agency unlimited consideration of
inventory methodologies, data reporting formats, projection techniques and
the other items discussed in the remaining sections of this chapter.
While air quality or emission control strategy inventories can be
initiated by an individual agency, most are undertaken as legal requirements
which usually set forth specific procedures to be used. The most commonly
required inventory is the SIP inventory. Requirements for these inventories
are outlined in EPA guidance 12 to 24 months before the SIP submittals are
to be completed. When using this volume to plan and develop a SIP VOC
inventory, it is suggested that applicable EPA guidance be consulted to
avoid employing inappropriate procedures.
In addition to fulfilling legal requirements, a good VOC control
strategy inventory can be very useful to an air pollution agency. On a day-
to-day basis, the point source listing of the inventory can be useful in
investigating citizen complaints and possible violations of emission codes.
In the long term, an accurate compilation of emissions in the inventory will
lead to better assessment of the impact of community growth on air quality.
By considering what uses the VOC emissions inventory will serve, the inven-
tory can achieve any program objective, whether research or regulatory in
nature.
2.2.2 SOURCES OF VOC EMISSIONS
An important consideration affecting emission accuracy is whether the
agency has included all sources of VOC in its inventory. Table 2.2-1 presents
those major sources of VOC that, at a minimum, should be considered in the
inventory. Some sources in this table are generally considered point sources,
some are generally handled collectively as area sources, while others, such
as drycleaners, can be either point or area sources, depending on the size
of each operation and the particular cutoff made between point and area
sources.
The entries in Table 2.2-1 describe general source categories and do
not list all of the emitting points that may be associated with any of the
particular source categories. For example, petroleum refining operations
actually include many emitting points ranging from process heaters to indivi-
dual seals and pumps. Appendix B contains a more detailed listing of pro-
cesses included in the categories shown in Table 2.2-1. General process and
emissions information on these sources may be obtained from AP-42, Compilation
of Air Pollution Emission Factors2 (including supplements) and in Appendix C
of this document.
Those stationary sources of VOC for which EPA has published or will
publish Control Techniques Guidelines (CTG) are included in the categories
listed in Table 2.2-1 and Appendix B. Summary information on many of these
sources is presented in Appendix C. Additional process, emission, and
control device information is available on these sources in the CTG documents
which are or will be available from the Director, Emission Standards and
Engineering Division, Mail Drop 13, U.S. Environmental Protection Agency,
Research Triangle Park, NC 27711. Many of these documents are cited in the
following chapters of this volume.
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Table 2.2-1. Volatile Organic Compound (VOC) Emission Sources.
STORAGE, TRANSPORTATION AND
MARKETING OF VOC
Oil and Gas Production & Processing
Gasoline and Crude Oil Storage1
Synthetic Organic Chemical Storage
& Transfer
Ship and Barge Transfer of VOC
Barge and Tanker Cleaning
Bulk Gasoline Terminals2
Gasoline Bulk Plants3
Service Station Loading (Stage I)
Service Station Unloading (Stage II)
Others
INDUSTRIAL PROCESSES
Petroleum Refineries
Lube Oil Manufacture
Organic Chemical Manufacture
Inorganic Chemical Manufacture
Fermentation Processes
Vegetable Oil Processing
Pharmaceutical Manufacture
Rubber Tire Manufacture
Plastic Products Manufacture
Rubber Tire Manufacture
SBR Rubber Manufacture
Textile Polymers & Resin Manufacture
Synthetic Fiber Manufacture
Iron and Steel Manufacture
Others
INDUSTRIAL SURFACE COATING
Large Appliances
Magnet Wire
Automobiles
Cans
Metal Coils
Paper
Fabric
Metal Wood Products
Miscellaneous Metal Products
Plastic Parts Painting
Large Ships
Large Aircraft
Others
NON-INDUSTRIAL SURFACE COATING
Architectural Coatings
Auto Refinishing
Others
OTHER SOLVENT USE
Degreasing
Dry Cleaning
Graphic Arts
Adhesives
Cutback Asphalt
Solvent Extraction Processes
Consumer/Commercial Solvent Use
Other
OTHER MISCELLANEOUS SOURCES
Fuel Combustion
Solid Waste Disposal
Forest, Agricultural, and Other
Open Burning
Pesticide Application
Waste Solvent Recovery
Processes
Stationary Internal Combustion
Engines
MOBILE SOURCES
Highway Vehicles
a. Light Duty Automobiles
b. Light Duty Trucks
c. Heavy Duty Gasoline
Trucks
d. Heavy Duty Diesel Trucks
e. Motorcycles
Off Highway Vehicles
Rail
Aircraft
Vessels
-"-Includes all storage facilities except those at service stations and bulk
.plants.
Loading tank trucks and rail cars.
Storage and transfer operations.
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2.2.3 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, the size of the inventory area, and data handling capabilities.
Administrative and secretarial support will be a function of the technical
manpower and budget allocations determined by all of the above factors.3'
Since cost and manpower requirements will vary for each inventory
effort, manpower and budget allocations should be determined case by case.
When an agency has conducted inventories regularly, its past experience can
be used to estimate requirements. If an agency desires a more detailed
determination of requirements, a computer model1* is available from EPA which
estimates technical and administrative costs associated with emission inven-
tories. To use the model, or to obtain additional information, contact an
EPA Regional Office or the Control Programs Operations Branch, Control
Programs Development Division, MD-15, U.S. Environmental Protection Agency,
Research Triangle Park, NC 27711.
2.2.4 GEOGRAPHICAL AREA
When planning a VOC emissions inventory, the responsible agency must
determine geographical boundaries within which emissions will be identified.
Statewide inventories provide a broad comprehensive data base which can be
useful but which require increased data handling. Historically, VOC inven-
tory efforts have often been confined to urban areas. Whatever area an
agency decides to inventory, the decision should be based on meteorological
and air quality data as well as on control strategy considerations.
Because ozone can form as a result of photochemical reactions many
miles downwind from the precursor pollutant sources, a fairly broad area
should be covered by a VOC emissions inventory. At a minimum, the urban and
suburban areas should be encompassed. Ideally, the inventory area should
include (1) all major emission sources that may affect the urban area, (2)
areas of future industrial, commercial and residential growth, (3) as many
ambient pollutant monitoring stations as possible, and (A) downwind receptor
sites of interest. In this last regard, the inventory area should encompass
areas downwind of the urban area where peak ozone levels occur. In general,
the area inventoried for a less data intensive source/receptor model such as
EKMA5 should be the same as the area that needs to be covered for use in a
photochemical model.
Modeling considerations are not the only factors influencing the
designation of the area covered by the inventory. In many cases the inven-
tory area will be prescribed to follow certain existing political boundaries.
Most commonly, county boundaries are followed. In certain cases, however,
other jurisdictions will be considered, such as cities, towns, townships, or
parishes. Typically, the inventory area includes a collection of such
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jurisdictions representing air basins or at least areas enduring common air
pollution problems. Air Quality Control Regions6 are examples of areas
that are used for inventory compilation purposes in ozone control programs.
In cases where the inventory area has not been prescribed, and if
uncertainties exist about future land use or the effect of meteorological
conditions, the agency should include as much area as possible. In this
way, a subset of the emission inventory can be used when the modeling and
control strategy analyses are subsequently made.
2.2.5 SPATIAL RESOLUTION
Because the less data intensive source/receptor relationships such as
EKMA are not sensitive to changes in the location of emissions, data compiled
at the county (or county equivalent) level generally provide sufficient
spatial resolution. The county limits are logical boundaries for compiling
an emission data base for two reasons. The first is because of the area
wide nature of the ozone problem. Ozone is generally not a localized
problem since formation occurs over a period of several hours, or in some
cases days, as a result of reactions among precursor pollutants emitted
over broad geographical areas. Consequently, less spatial resolution is
generally required for volatile organic emissions than is necessary for
other pollutants.
The second reason for compiling volatile organic emission inventories
on a county basis is because of data availability. The county represents
the smallest basic jurisdiction for which various records are typically
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 to be used in developing an ozone control strategy.
Countywide emissions can be summed to compile total emissions for an entire
inventory area.
2.2.6 BASE YEAR SELECTION
Selecting the appropriate base year for the emission inventory is a
straight forward task. The selection of the base year may depend on the
years for which the agency has good air quality data, if the agency is
attempting to relate air quality and emissions. However, in most control
strategy inventories, the inventory base year will be determined by legal
requirements, such as those set forth by EPA for SIP inventories. In any
case, the base year should be determined before initiating data collection.
2.2.7 TEMPORAL RESOLUTION
Because simpler source/receptor models are not particularly sensitive
to small scale temporal variations in emissions, the VOC inventories used
in these models do not need to be temporally resolved to the extent necessary
for the more complex photochemical models. Thus, inventories of annual
emissions will generally suffice. Annual emissions data have historically
been collected by most agencies for various reasons, mainly because annual
activity levels are most readily available for certain sources.
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In some cases, the agency may find it worthwhile to consider adjusting
the annual emission estimates to more accurately reflect VOC emission rates
during the ozone season. The major categories whose VOC emissions may be
significantly different during the ozone season are mobile sources and
petroleum product storage and handling operations. Of course, any source
whose activity is known to vary seasonally will have varying emission rates.
Seasonal adjustment of VOC emissions is discussed in Chapter 6.
If, for some reason, an inventory of daily emissions has been compiled,
such an inventory is also suitable for use in a less data intensive source/
receptor model such as EKMA. This is because in such models, the relative
emission contribution from of each source is used to define control measures
rather than the absolute quantity of emissions from each source. As long as
the relative importance of each source is roughly the same, annual, seasonal
or daily inventories may all be used with the less data intensive models.
2.2.8 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 (or have the potential to
emit) more than some specified cutoff level of VOC are considered point
sources. Depending on the needs of and resources available to the agency,
this cutoff level will vary. Area sources, in contrast, are those activ-
ities for which aggregated source and emission information is 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 so 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, emis-
sions from these sources may not be included in the inventory at all.
Techniques are available for "scaling up" the inventory to account for
missing sources (see Chapter 6.4). However, such 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 size of the point source file that must be 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 commonly recommended upper limit on the VOC point source cutoff level
is 100 tons/year. If resources allow, a lower cutoff level is encouraged.
A recent study in several urban areas has shown the existence of many VOC
sources emitting less than 25 tons per year.7 Moreover, many of these
sources are in categories for which no reliable area source inventory pro-
cedures currently exist. Because of this, some agencies have opted to
^lof-i^o ^,,1-ofp ir-.-oir. K -i,-,,., s tons per year in order to directly cover a
larger percentage of VOC emissions in a point source inventory.
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Deciding the point/area source cutoff level should be done carefully.
For this reason, the reader is referred to the additional discussion on the
point/area source cutoffs in Chapter 3.0.
2.2.9 DATA COLLECTION METHODS
Several methods are presented in this volume for collecting data for
point and area sources of VOC emissions. However, the inventorying agency
must decide which procedures to use in an VOC inventory effort. Point
source methods include mail surveys, plant inspections, use of agency permit
and compliance files, and source listings. Area source methods include
modified point source methods, local activity level surveys, apportioning of
state and national data, per capita emission factors, as well as emissions-
per-employee factors.
To a certain extent, determining which data collection methods to
employ will occur during the data collection, as the agency receives feed-
back on the success of data collection. However, the agency should, whenever
possible, determine in the planning phase what methods will be used in data
collection. Determining in advance which methods to use will allow time to
obtain necessary reference and support materials and will help better allo-
cate work hours to the individual data collection tasks as well.
The data collection methods and considerations for their use are
discussed in greater depth in Chapters 3 and 4. The reader should refer to
these chapters prior to selecting point and area source collection procedures
for a VOC emission inventory.
2.2.10 EXCLUSION OF NONREACTIVE COMPOUNDS AND CONSIDERATION OF SPECIES
INFORMATION
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)
These compounds should be excluded from emission inventories used for ozone
control strategy purposes. The reader is directed to References 8 through
10 for more detailed information on the subject. Because this list may
change as additional information becomes available, the inventory agency
should remain aware of EPA policy on reactivity considerations.
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Most of the nonreactive volatile organic compounds that should be
excluded are halogenated organics that find principal applications as
cleaners for metals and fabrics, as refrigerants, and as aerosol propellants.
Hence, major emitting sources of many of these nonreactive compounds can be
readily identified because the sources should be able to specify which
solvents are being used in their operations. To this end, solvent use
information is generally asked for on most questionnaires, and should be
solicited in any other types of plant contacts that are made.
All combustion sources will emit methane and lesser amounts of ethane.
Most emission sources will not be able to tell the agency what fraction of
their VOC emissions are comprised of these nonreactive compounds. Reference
11 should be consulted for information on species compositions of various
VOC emitting sources. Highway vehicles represent the most important combust-
ion source emitting significant quantities of methane. Available EPA emis-
sion factors allow the user to exclude methane from highway vehicle emissions.12
EKMA and other less data intensive source/receptor models do not require
information on individual organic species or reactivity classifications
which are required by more detailed photochemical simulation models. Hence,
the agency need not develop and maintain data on individual organic compounds
in the basic inventory for the less data intensive models. Instead, to the
extent feasible, the agency need only identify that fraction of emissions
from each source comprised of nonreactive VOC and exclude it from the VOC
emission total.
Even though species data are not needed in the basic inventory, the
agency may find it worthwhile in some instances to collect this information
when plant contacts and surveys are made during the basic inventory compil-
ation effort. If an agency anticipates using a photochemical model, species
data will become necessary. Moreover, data may need to be maintained on
certain toxic organic materials for use in other regulatory programs. If
either of these other activities is planned for the near future, it is more
efficient to collect species data at the same time the other source and
emissions data are collected for the basic inventory. In this regard, the
agency should generally minimize the number of contacts required to any one
source.
2.2.11 EMISSION PROJECTIONS
An essential element in an ozone control program is emission projec-
tions. Two types of projections are generally made: baseline and control
strategy. Baseline projections are estimates of emissions in some future
year that take into account the effects of growth and existing control
regulations. A baseline projection is essentially an estimate of what
emissions would be if no new control measures were put in place, but still
taking anticipated growth into account. The baseline projection inventory
is important in a control program because it serves as a reference point to
determine if sufficient precursor pollutant reduction is being achieved in
order to meet the ambient ozone standard. The baseline inventory can serve
as an accurate reference point only if expected growth is included.
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In contrast, control strategy projections are estimates of emissions in
some future year, considering additional control measures. Control strategy
projections should be made for the same projection years as the baseline
projection inventories. This enables the agency to directly compare the
relative effectiveness of each strategy as well as to determine which
strategy provides the necessary control of ozone precursor emissions as
indicated by the source/receptor relationship.
Two fundamentally different approaches can be used to make projections.
Simple but somewhat crude projections can be made by multiplying base year
summary emission estimates by general growth factors. Typically, such
growth factors are surrogate indicators of activity level growth, such as
industrial output, that have been adjusted to reflect some average measure
of control reduction for each source category.
The alternative to the above approach is to make detailed projections
for each point source. In such a detailed approach, information on antic-
ipated expansion, process changes, and control measures is collected from
eac-h source, at the same time and in the same manner as the base year source
and emissions data are collected. As a result of this approach, an entire
inventory file is created for the projection year, rather than just a summary
listing. This second approach, theoretically, results in more accurate
projections because growth to capacity, new growth, and individual control
measures can all be taken directly into account. Because of increased
accuracy, the agency should generally consider making projections at the
greatest level of detail possible, within given resource constraints. If
the agency anticipates building on the basic inventory at some later date in
order to run a photochemical model, detailed projections are needed to
provide the temporal and spatial resolution necessary in such models.
Emission projections are discussed in Chapter 6.
When making projections, the agency should check that consistent
methodologies are used for each source category in both the base year and
projection year inventories. If different procedures are used for esti-
mating emissions, the agency cannot be sure if changes in emissions are due
to its proposed control program or simply due to methodological differences.
For example, if local dry cleaning solvent consumption is determined from
plant questionnaires in the base year, projection year solvent consumption
should not be estimated by apportioning projected nationwide solvent use to
the local level.
Another important point to keep in mind during the planning stages is
that the structure of the inventory determines how readily the impact of
various control strategies can be estimated. For example, if a certain
control measure is to be imposed on "perc" dry cleaning plants, the effect
of that control is more readily simulated in a projection year inventory if
emission totals for perc plants are maintained distinct from emissions from
plants using petroleum or fluorocarbon solvents. Thus, the agency should
anticipate what control measures are likely candidates for evaluation and
should structure the source categories, data elements, and reporting capa-
bilities accordingly, so these measures can be easily reflected in the
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projection inventory. Table 2.2-1 and Appendix B illustrate a format which
includes most categories for which control measures have been or will be
developed.
2.2.12 STATUS OF EXISTING INVENTORY
A major inventory design consideration, especially if the agency is
faced with limited resources, is whether or not an existing inventory can be
used as is, or selectively modified, to meet the current needs of the ozone
control program. No specific guidance can be offered here, since existing
inventories will obviously differ, as will the current needs of each agency.
At a minimum, the existing inventory should be examined to see if the appro-
priate sources have been included and that the emissions data therein are
reasonably representative of current conditions. The point source cutoff
level for VOC emissions should be compared with current requirements. If,
for some reason, the existing inventory cannot meet current needs, and can-
not readily be updated or modified, it should not be discarded as totally
useless. Previous inventories can at least serve as a starting point for
the development of a mailing list for questionnaire distribution. The
agency must be careful, however, not to rely on an existing inventory to the
degree that important VOC sources or source categories are excluded. These
sources may either have been (1) erroneously omitted when the original
inventory was prepared or (2) omitted because VOC sources were never required
to obtain permits. In the latter, many inventories have historically been
compiled for particulate (TSP) and SOX with little emphasis on sources
exclusively emitting VOC. Any backup information kept on the existing
inventory can also be helpful, such as the response time required for question-
naires, etc. Likewise, any specific emission factors, per capita factors,
or other rules of thumb resulting from a previous inventory may still be
applicable in a current effort.
2.2.13 CORRESPONDING NITROGEN OXIDES (NOX) INVENTORY
Nitrogen oxides, along with volatile organic compounds, are precursor
emissions that react to form photochemical oxidant. Consequently, a NOx
emission inventory is important in an ozone control program as well as in a
VOC inventory. The EKMA model estimates of both VOC and NOX are directly
used to generate the city-specific ozone isopleths.5
NOX emissions are generally easier to inventory than VOC because most
originate from combustion sources. Mobile sources and boilers typically
account for the bulk of NOx emissions in most urban areas. Other combustion
sources of NOX include internal combustion engines, incinerators, industrial
sources using in-process fuels, and various open burning operations. In
general, the procedures presented in this volume will adequately cover all
of these sources of NOX. Care should be taken that those few noncombustion
sources emitting NOx, but not VOC, are included in the inventory. Nitric
acid, adipic acid, and nitrocellulose production, as well as explosives
manufacturing, are examples of such source categories. Construction of a
list of all sources of NOX within the inventory area will aid in identifying
these noncombustion sources.
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2.2.14 DATA HANDLING
The agency conducting an emission inventory should be aware that data
handling and retrieval can be done by computer or manually. Combinations of
these two basic approaches are also possible. The selection of one approach
over the other will depend on several factors:
0 availability of a computer
0 size of the inventory data base
0 complexity of the emission calculations
0 number of calculations to be made
0 variety of tabular summaries to be generated
0 availability of clerical and data handling personnel
0 time constraints
The computer approach 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 computer approach generally 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:
0 printing mailing lists and labels
0 maintaining status reports and logs
0 calculating and summarizing emissions
0 storing source, emissions, and other data
0 sorting and selective accessing of data
0 generating output reports
Therefore, 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. In general,
if an agency must deal with large amounts of data, a computerized inventory
data handling system allows the agency to spend more time gathering and
analyzing the inventory data as opposed to merely manipulating it. In this
sense, the computerized approach is superior in large areas having a diversity
of sources comprising a complex inventory.
To facilitate the reporting of the local inventory data to EPA, consid-
eration should be given to using either of EPA's inventory data handling
systems (NEDS or EIS/P&R) or to developing a system that is compatible. One
particular advantage of this is that numerous summary routines and various
computer modeling programs have been designed to operate on the NEDS and EIS
data bases, including a wide variety of retrieval programs that enable the
user to provide summaries of source, control device, and emissions data for
a number of geographical areas down to the county level. NEDS and EIS are
described briefly in Appendix F, and in more detail in References 13 through
17.
If the agency anticipates use of a photochemical dispersion model at
some future date, it is imperative that a computerized data handling system
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be utilized. The added complexity involved in developing spatially and
temporally resolved estimates of several VOC classes from the basic inven-
tory simply represents too much work to complete manually. Generally any
area large enough to warrant the use of a photochemical model will have a
computerized data handling system in place to handle the important inventory
functions. Data handling requirements for inventories used in photochemical
models are discussed in Volume II.
Quality assurance is another consideration for selecting a computer
system for data handling. A computer can conduct emission calculation and
editorial checks much faster than doing them manually. Thus, how an agency
intends to conduct quality assurance tests on the emissions inventory should
be considered when deciding on manual or computer handled data systems.
2.2.15 QUALITY ASSURANCE
Quality assurance is important in achieving user confidence in an
emission inventory. A quality assured inventory will result in better
assessment of emission inputs on air quality. Also, lower program costs may
be realized because inventory updates and revisions will not be as extensive
as would be expected without a quality assurance program.
A quality assurance program applied to emission inventory procedures
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. Tech-
niques 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 provi-
sion 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.
With the exception of computerized data processing, the emission inven-
tory process focuses on human factors. As a consequence, quality assurance
for emission inventory applications might be weighted more heavily toward
procedures analysis, the first two of the above procedures. Standard
operating procedures can be outlined as the inventory effort is planned.
Identifying and correcting inconsistenies and errors in the inventory can
also be anticipated in the planning phase. The following potential error
sources can be found in most emission inventories.
° Missing facilities or sources - Permit and inventory systems out of
phase; errors in estimating potential emissions; lost paperwork; problems
with computer file updates.
0 Duplicate facilities or sources - Name changes through corporate
acquistions; use of multiple data sources with different source numbering
schemes.
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0 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.
0 Erroneous technical data - Misinterpretation of data request instruc-
tions; assumed units, faulty conversions, etc.; intentional misrepresenta-
tion by the facility; poor handwriting.
0 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.
0 Inconsistent area source categories or point source sizes - Failure
to designate inventory cutoffs.
0 Inaccurate or outdated data - Mixed use of primary and secondary data
without a standard policy.
0 Errors in calculations - Transposition of digits; decimal errors;
entering wrong numbers on a calculator; misinterpreting emission factor
applications.
0 Errors in emission estimates - Imprecise emission factors; applying
the wrong emission factor; errors in throughput estimates; improper interpre-
tation of combined sources; errors in unit conversions; faulty assumptions
about control device efficiency; failure to exclude nonreactive emissions.
0 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.
Product quality is more difficult to assess in an emission inventory
than in a quality assurance application involving physical instruments such
as pollutant analyzers, monitoring sites, and calibration equipment. If a
computer data handling system is available, a computer program can perform
checks on point source data records. A program could check 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.
Principles of quality assurance can be applied in planning, data collec-
tion, calculations, and reporting of a VOC emission inventory. Quality
assurance can be made quite effective by anticipating the measures needed in
each of these inventory functions. To promote effective quality assurance,
the inventory planner should consider the principles listed below prior to
initiating inventory tasks.18
Planning:
0 Plan to allocate resources for maximum quality assurance.
0 Plan to account for significant VOC emission sources.
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Prepare a checklist of sources to be evaluated.
Use staff experienced in data collection and analysis.
Plan for routine checking of calculations.
0 Plan checking of data file entries.
Prepare data checking programs (when using a computer for data
handling).
Maintain a separate quality assurance staff.
Plan audit procedures.
Data collection and analysis:
Use redundant identification of major sources (quality assurance
staff should prepare an independent source list).
0 Check questionnaire design.
Check questionnaire responses.
0 Check data collected.
0 Check emissions estimation methods.
0 Check calculated results.
Verify adherence to quality assurance procedures.
Data handling:
0 Check data file entries.
Check individual data entries (missing emissions,
SIC codes, addresses, etc.)
Assign agency estimates for missing data.
0 Check for data correctness.
0 Review tabulated data for quality.
Data reporting:
Check the aggregation of emissions.
0 Compare results with those of other inventories.
Check disaggregation of emissions (if allocated to subcounty
areas).
The above is intended as a primer to acquaint the user with the concepts
and principles of quality assurance. Before planning a quality assurance
program, the reader should obtain additional information on these concepts
and principles. Such information on emission inventory quality assurance
can be found in References 18 through 20 or can be obtained through an EPA
Regional Office.
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2.2.16 DOCUMENTATION
Documentation is an integral part of a VOC emission inventory. By
documenting an inventory's supporting materials, errors in procedures,
calculations or assumptions are detected easier. In addition, a well docu-
mented inventory will be a defensible data base which is valuable in enforce-
ment actions, source impact assessments, and development of emission control
strategies as well.
While documentation requirements may evolve during the data collection,
calculation, and reporting steps of the emission inventory, these require-
ments should be anticipated in the planning phase. Planning what level of
documentation required will (1) ensure that important 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 hard copy file and computer data storage requirements, and (4) aid
in identifying aspects of the inventory on which to concentrate quality
assurance efforts. Thus, planning documentation for the emissions inventory
will benefit both the emissions inventory effort and the agency.
2.2.17 ANTICIPATED USE OF A PHOTOCHEMICAL DISPERSION MODEL
The basic inventory compiled for use with a less data intensive source/
receptor model can serve as a good starting point for creating a photo-
chemical modeling inventory. If the agency expects to use a photochemical
dispersion model at some subsequent date without redoing the existing data
base, certain considerations should be made in the basic inventory effort
from the outset.
An example of such a consideration is given in Section 2.2.14. Because
of the extensive data handling activities required in producing a photo-
chemical modeling inventory, a computerized inventory file should be developed
from which a "modeler's tape" can be created. (The modeler's tape is the
final inventory product that is actually input to the photochemical model.)
The amount of source data that should be collected during the basic
inventory update will be increased if the agency anticipates the use of a
photochemical dispersion model. If a photochemical model is to be used,
sufficient additional information should be collected to allow the agency to
develop the necessary spatial and temporal resolution and VOC classifications
needed by these models. Specifically, (1) detailed locational coordinates
and stack data should be obtained for each point source (this information is
already maintained in many basic inventory systems), (2) socioeconomic data
should be obtained for subsequent area source apportioning, (3) daily and
hourly operating patterns are needed for the ozone season, and (4) VOC
species profiles should be defined for each emissions category. In order to
minimize the number of contacts made to any particular source, the agency
should obtain as much of this additional information as possible during the
contacts made to update the basic inventory. Volume II further discusses
the data requirements for photochemical modeling inventories.
A third consideration influences the structure of the basic inventory.
Because VOC emissions must be apportioned to various classes in the photo-
chemical modeling inventory, the basic inventory should be structured to
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facilitate this step. To a large extent, this can be effected by a judicious
choice of source categories. As an example, drycleaning plants using
perchloroethylene should be distinguished from those using petroleum solvent
because each of these solvents needs to be apportioned differently into VOC
classes. As another example, evaporative and exhaust emissions from gasoline
powered vehicles should be distinguished because these emissions are comprised
of such different organic species. In general, if separate emission totals
can be maintained for the important solvents used in an area, and the exhaust/
evaporative distinction is maintained for gasoline powered vehicles, the
basic inventory can readily be used for generating the VOC classifications
needed by photochemical models. Maintaining separate totals for various
solvent types is useful in the basic inventory as well, because the agency
can more readily exclude those particular compounds (discussed in Section
2.2.10) that do not participate in ozone formation.
Volume II1 of this series should be studied during the planning stages
of the basic inventory process, if the agency may run a photochemical model
in future modeling analyses.
2.2.18 PLANNING REVIEW
By the completion of the planning phase of the inventory effort, and
prior to initiating the data collection phase, the agency should have
addressed the items listed below.
0 The end use(s) of the inventory are established.
0 Source categories have been defined which are compatible with
available source and emission information, and are of sufficient detail to
faciliate control strategy projections excluding nonreactive compounds.
0 Manpower and budget allocations have been made.
0 The geographical inventory area has been identified and the neces-
sary spatial allocation determined.
0 The inventory base year has been selected.
0 Decisions have been made on whether to adjust emissions seasonally,
which sources will be seasonally variable, and whether emissions will be
compiled annually or daily.
0 The point source cutoff has been defined, the relative quantity of
sources below the emissions cutoff level has been estimated, and scaleup and
area source procedures selected.
0 How point and area source data can best be collected has been
determined.
0 Procedures for identifying nonreactive emissions have been selected.
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0 The agency has decided on how emissions will be projected and the
projection period, including end year and intermediate years, has been
designated.
0 The role of existing inventory data has been determined and any
previously omitted important VOC sources have been identified.
All souices of NOx emissions are identified, including noncombustion
industrial processes which do not emit VOC.
0 An inventory data handling system has been selected.
0 Quality assurance procedures have been selected.
0 The agency's future use of a photochemical dispersion model has
been considered and the appropriate adjustments in inventory plans have been
made, including review of Volume II, if necessary.
References for Chapter 2.0
1 Procedures for the Preparation of Emission Inventories for Volatile
Organic Compounds. Volume II. EPA-450/4-79-018, U.S. Environmental
Protection Agency, Research Triangle Park, NC, September 1979.
2 Compilation of Air Pollutant Emission Factors, Third Edition and
Subsequent Supplements, AP-42, U.S. Environmental Protection Agency,
Research Triangle Park, NC, August 1977.
3 James H. Southerland, "Emission Inventories: A Perspective," presented
at the 71st Annual meeting of the Air Pollution Control Association,
Houston, TX, June 25-30, 1978.
4 Thomas Donaldson and Michael Senew, "Estimating the Cost of State
Emission Inventory Activities," presented at the 73rd Annual Meeting of
the Air Pollution Control Association, Montreal, Canada, June 22-28,
1980.
5. Uses, Limitations and Technical Basis of Procedures for Quantifying
Relationships between Photochemical Oxidants and Precursors,
EPA-450/2-77-021a, U.S. Environmental Protection Agency, Research
Triangle Park, NC, November 1977.
6. Federal Air Quality Control Regions, AP-102, U.S. Environmental
Protection Agency, Rockville, MD, January 1972.
7 Mahesh C. Shah and Frank C. Sherman, "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.
8. Recommended Policy on the Control of Volatile Organic Compounds,
42 FR 35314, July 8, 1977.
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9. Clarification of Agency Policy Concerning Ozone SIP Revisions and
Solvent Reactivities, 44 FR 32042, June 4, 1979, and 45 FR 32424, May
16, 1980.
10. Clarification of Agency Policy Concerning Ozone SIP Revisions and
Solvent Reactivities, 45 FR 48941 July 22, 1980.
11. Volatile Organic Compound Species Data Manual, Second Edition,
EPA-450/4-80-015, U.S. Environmental Protection Agency, Research
Triangle Park, NC, July 1980.
12. User's Guide to MOBILE1, EPA-400/9-78-007, U.S. Environmental Protection
Agency, Washington, DC, August 1978.
13. AEROS Manual Series, Volume I: AEROS Overview, EPA-450/2-76-001 U.S.
Environmental Protection Agency, Research Triangle Park, NC, February
1976.
14. AEROS Manual Series. Volume II: AEROS Users Manual, EPA-450/2-76-029,
U.S. Environmental Protection Agency, Research Triangle Park, NC,
December 1976.
15. AEROS Manual Series, Volume III: Summary and Retrieval Second Edition,
EPA-450/2-76-009a, U.S. Environmental Protection Agency, Research
Triangle Park, NC, July 1977.
16. The Emissions Inventory System/Area Source User's Guide, EPA-450/4-
80-009, U.S. Environmental Protection Agency, Research Triangle Park,
NC, May 1980.
17. The Emissions Inventory System/Point Source User's Guide, EPA-450/4-
80-010, U.S. Environmental Protection Agency, Research Triangle Park,
NC, May 1980.
18. Rich Bradley, Joan Stredler, Hal Taback, "Improving Emission Inventory
Quality - A QA/QC Approach," presented at the 73rd Annual Meeting of
the Air Pollution Control Association, Montreal, Canada, June 22-21,
1980.
19. Development of an Emission Inventory Quality Assurance Program,
EPA-450/4-79-006, U.S. Environmental Protection Agency, Research
Triangle Park, NC, December 1978.
20. I. M. Goklany, "Emission Inventory Errors for Point Sources and Some
Quality Assurance Aspects," Journal of the Air Pollution Control
Association, 30(4): 362-5, April 1980.
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3.0 POINT SOURCE DATA COLLECTION
As discussed in Chapter 2, point sources are those facilities/plants/
activities for which individual records are maintained in the inventory.
Two major decisions must be made during the planning stages that will have a
major impact on the scope of the point source inventory: (1) what cutoff
level will be chosen to distinguish point from area sources and (2) what
procedures will be employed to collect data on each facility.
The choice of a point source cutoff level will not only determine how
many point sources will be contained in the inventory, but also will impact
on the kinds of sources included. As a rule, the lower this cutoff level
is, (1) the greater the cost of the inventory, (2) the more confidence users
will have in the source and emissions data, and (3) the more applications
that can be made of the inventory. At a minimum, all facilities exceeding
100 tons of VOC per year should be inventoried as point sources and each
process emission point should be identified. If possible, a point source
cutoff level of less than 100 tons per year should be selected to avoid
handling the myriad of medium size VOC emitters found in most urban areas as
area sources. In some cases, the agency may decide to pursue lower cutoff
levels or to simply include all of a certain type of source in the point
source inventory, regardless of size. This may be desirable, for example,
if all sources in a certain category are subject to control regulations such
as RACT.
Prior to the point source data collection effort, all planning consid-
erations discussed in Chapter 2 should also be taken into account. At a
minimum, every source category shown in Table 2.2-1 and the process emission
points shown in Appendix B should be considered for inclusion, with an
emphasis on those RACT categories for which controls are anticipated in the
ozone control program. As an aid to the agency in this regard, Appendix C
contains summary information on each source category for which EPA has
published a Control Techniques Guideline (CTG) document. This information
can help the agency decide whether a given source category (or some segment
thereof) should be included in the point source inventory; what processes
need to be identified as distinct emitting points; what kinds of controls
represent reasonably available technology; and what presumed reductions are
related to the implementation of these controls. The CTG documents cited in
Appendix C should be studied by the inventory agency, as they contain a
great deal of detailed source, emissions, and control device information on
the major sources that should be encompassed in a VOC inventory.
The second major decision regards what particular procedures should be
used to collect data for each point source category. All point source
procedures have two common elements: (1) they all involve some sort of
direct plant contact and (2) an individual point source record is generated
as a result of the plant contact that is maintained as a separate entry in a
point source file. Plant contacts of various sorts can be made. The two
most common types of plant contact are the mail survey and direct plant
inspections. A type of indirect plant contact also commonly employed is the
use of permit applications or compliance files. These three techniques for
collecting point source data are discussed in this chapter.
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3.1 QUESTIONNAIRES (MAIL SURVEY APPROACH)
A common technique used by air pollution control agencies for gathering
point source emission inventory data is the mail survey. The primary purpose
of a mail survey is to obtain source and emission data by means of a question-
naire mailed to each facility. In order to conduct this type of data gather-
ing operation efficiently, the facilities to be surveyed must be identified;
mailing lists must ^e prepared; questionnaires must be designed, assembled
and mailed; data handling procedures must be prepared and organized; and
response receiving systems must be established. The following text discusses
the details of each of these general operations.
3.1.1 PREPARING THE MAILING LIST
A necessary step in the mail survey is the preparation of a mailing
list that tabulates the name, address, and general process category of each
facility to be surveyed. The basic function of the mailing list is to
identify those sources to which questionnaires will be sent. The mailing
list may also serve other functions. For example, the general process
category information obtained from the mailing list can assist the agency in
the determination of those categories for which questionnaires must be
designed. In addition, the size of the resulting mailing list gives the
agency an indication of how many of what kinds of sources can effectively be
considered in the point source inventory within resource limitations. In
this regard, the mailing list can be used to help the agency determine if
the resources allocated for the compilation effort will be sufficient.
Frequently, more sources are identified than are believed to exist during
the initial planning stages.
The mailing list is compiled from a variety of information sources,
including the following:
0 Existing inventories - An existing inventory is a good starting
point if it is not over several years old or if it has been frequently
updated and will documented. Caution is in order since many inventories are
compiled for pollutants other than VOC. Hence certain sources, such as
solvent users emitting only VOC, may not be well represented in existing
inventories. Moreover, some sources of VOC that are considered collectively
as area sources within the existing inventory may, instead, need to be
treated as point sources in the updated VOC inventory.
0 Other air pollution control agency files - Compliance, enforce-
ment, permit application, or other air pollution control agency files may
provide valuable information on the location and types of sources that exist
in the area of concern. These files can also be utilized later to cross
check certain information supplied on questionnaires.
0 Other government agency files - Files maintained by labor depart-
ments and tax departments frequently aid in the preparation of the mailing
list. Such files would include various state industrial directories wherein
companies are listed alphabetically by SIC and county. The information
available in these files will vary from state to state. Thus, it is advis-
able to contact the appropriate personnel within these agencies to become
familiar with what listings are available.
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0 EPA/CTG source listings - EPA's Division of Stationary Source
Enforcement has developed point source listings for several source cate-
gories for which CTG documents have been published.1"8 The listings provide
a company name, address, and in some cases, a phone number for each source.
These listings are available through EPA Regional offices upon request by a
State or local air pollution control program. In addition, EPA is develop-
ing a more detailed RACT compendium for VOC sources. Included in the compen-
dium are additional source categories for which EPA intends to publish CTG
documents (see Appendix C). As the compendium becomes available, it will be
also made available through EPA Regional offices.
0 Other local information sources - The following local information
sources can be consulted, where available:
- Local industrial directories - A local industrial development
authority may provide a list of the latest sources which operate in the
inventory area.
- Yellow Pages - The local telephone directory will have names,
addresses and phone numbers of many industrial/commercial VOC sources.
Caution is advised in that phone directory areas often do not correspond to
county or community boundaries.
- Manufacturers and suppliers - Contact firms that make or supply
equipment and materials used in industries emitting VOCs, such as solvents
storage tanks, gasoline pumps, or VOC emissions control equipment. Some
firms have good contacts within industry and may be able to provide infor-
mation concerning the existence and location of VOC sources.
0 National publications - The national publications listed below can
be used when available. However, the information contained in them may be
older and less accurate than local primary references.
- Dun and Bradstreet, Million Dollar Directory9 - Companies with
sales over $1,000,000 a year are compiled by SIC and county.
- Dun and Bradstreet, Middle Market Directory10 - Companies with
sales between $50,000 and $1,000,000 a year are compiled by SIC and
county.
- Dun and Bradstreet - Industrial Directory11
- National Business Lists12 - Companies are listed by SIC and
county with information on financial strength and number of employees.
- Trade and professional society publications13*1^ - Names and
addresses of members are listed along with their type of business.
When compiling the final mailing list, special attention should be
given to the Standard Industrial Classification (SIC) code associated with
each source, when it is known. SICs are a series of codes devised by the
U.S. Office of Management and Budget to classify establishments according to
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to the type of economic activity in which they are engaged.15 If an SIC
corresponds to one given in Table 3.1-1, an increased likelihood exists
that the source is an important source of VOC emissions.
Once these various sources have been consulted and a mailing list
drafted, the list should be ordered to facilitate the necessary mailing and
followup activities. A logical order in which to list companies is by city
or county, then by SIC, and finally, alphabetically. Ordering the list in
this manner will increase the efficiency of all subsequent data handling
tasks. Visual spot checking of the resulting listing will eliminate many
of the duplications.
3.1.2 LIMITING THE SIZE OF THE MAIL SURVEY
If more sources are identified on the mailing list than can be handled
within available resources, the agency should screen the mailing list in
some manner to reduce the number of facilities to be sent questionnaires.
This can be done in a number of ways. One way is to limit the mailout to
only those sources believed to emit annually more than a certain quantity
of VOC. Appendix C contains estimates of typical VOC emissions associated
with industrial processes within many important source categories. These
typical emission estimates can be used to determine if certain operations
should be handled as point or area sources. For example, in Table C-21 of
Appendix C, typical coin operated ("coin-op") and commercial dry cleaning
plants are estimated to emit only 1.6 and 3.6 tons per year, respectively.
Hence, if the agency's point source cutoff level is 25 tons per year, it
may decide to treat all coin-op and commercial plants as area sources, and
not send them questionnaires.
In many instances, the number of employees in a company will be known,
and an estimate of the potential magnitude of emissions can be made by
applying emission-per-employee factors, such as are shown in Table 3.1-1.
The range of emissions in Table 3.1-1 for some two-digit Standard Industrial
Classification (SIC) categories suggests that this technique may yield
widely varying estimates of a source's annual emissions. If the agency has
sufficient budgeted resources, the higher emission-per-employee factors can
be used. This will cause an initial overestimate of each point source's
emissions, placing more sources above the determined cutoff level. As a
result, questionnaires will be sent to more sources.
Another method for reducing the mailing list to a manageable size is
to make telephone contacts to selected sources within each major category.
If there is any doubt about particular source types being potentially large
emitters, brief contacts with plant managers or other appropriate employees
at a few representative facilities may indicate if VOC emitting processes
are common. Moreover, by obtaining activity levels or the number of employees,
the agency can estimate what facilities within the source category will be
of sufficient size to warrant receiving a questionnaire.
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Table 3.1-1. Standard Industrial Classifications (SICs) Associated
With VOC Emissions; Emission-Per-Employee Ranges8'9
General 2-Digit
SIC Categories
Specific 4-Digit
SIC Categories
Emission-Per-Employee
Ranges (tons/employee/yr)
20 Food
21 Tobacco
22 Textiles
23 Apparel
24 Lumber & wood
25 Furniture &
fixtures
26 Paper
27 Printing
28 Chemicals
29 Petroleum
30 Rubber, Plastic
31 Leather
32 Stone, clay, etc
33 Primary metal
34 Fab. metal
35 Machinery
36 Elect. Machinery
37 Transpt. equip.
38 Instruments
39 Misc. Mfg.
5171 Bulk terminals
7216 Dry cleaning
Alcoholic beverages
(2085)
Not surveyed
Coating (2295),
Non-wovens (2297),
Dyeing (2231)
Not surveyed
Finished product (2435),
(2492)
SIC: (2511), (2514),
(2521), (2522), (2542)
Bags, box (2643),
(2651), (2653),
Coated papers
(2641)
Newspaper publishing
(2711), Comm.
printing (2751),
(2754)
Organic chemical mfg.
(2821), (2823), 2861),
Chemical coating (2851).
Specialty chemical (2842),
Carbon black (2895)
All companies
Footwear (3021), Plastics
(3041), (3069)
Mfg. shoes (3149), Bags
(3161), Personal goods
(3172), Leather
refinishing (3111)
Glass products (3221)
Treating (3398), Tubing
(3357)
Screws (3451-2), Metal
stampings (3469), Plating
(3471), Tool mfg. (3423),
(3429)
Industrial machines
Devices (3643), Semicond.
(3674)
Boats (3732), Truck bodies
(3711), 13, 14, 15)
Optical frames (3832)
Precision instruments
Jewelry (3914-15), Toys
(3944), Writing instr.
(3951,53)
All surveyed
All surveyed
0.075
0.536-0.89
0.024-0.07
0.08-0.24
1.0-1.25
0.08-0.05
0.32-0.357
0.11-2.12
0.16-0.256
0.13
0.03-0.092
0.10-0.267
0.19-0.281
0.03-0.048
0.04-0.07
0.11-0.855
0.04-0.199
0.07-0.59
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3.1.3 DESIGNING THE QUESTIONNAIRES
After the mailing list has been prepared, a questionnaire must be
prepared for each facility to be contacted. This can be done either by
preparing industry-specific questionnaires for each source category or by
preparing "catchall" questionnaires that encompass many source categories.
If sufficient resources are available, industry specific questionnaires are
advantageous for certain sources. Such questionnaires will generally be
shorter, because questions not applicable to the particular industry need
not be included. In addition, industry-specific terminology can be used
that is familiar to those working in a particular industry but which may not
be understood by others. This can enhance communication and reduce confusion.
For these reasons, inventory accuracy is increased when industry-specific
questionnaires are used. On the other hand, this approach has several
disadvantages. One disadvantage is that the design of many industry-specific
questionnaires requires significant resources. Second, all the returned
questionnaires cannot be processed in the same way because of the variations
in format that will exist from questionnaire to questionnaire. Third,
incorrect industry-specific questionnaires may be inadvertantly sent to some
sources because of limited prior knowledge of the operations at these sources.
Generally, if the mailing list is long, if the agency is unfamiliar
with many of the sources on the list, or if agency resources are limited,
the use of general questionnaires may be advisable. Oftentimes in practice,
a general questionnaire is merely a collection of process-specific question-
naires sent out as one questionnaire.
Questionnaire design entails the establishment of a suitable format,
the selection of appropriate questions, the wording of questions, and the
development of an appropriate cover letter and instructions for filling out
the questionnaire. The basic rule is to design the questionnaire for the
person who will be asked to complete it. The agency should consider the
fact that the person who will complete the questionnaire may not have the
benefit of a technical background in air pollution, engineering, or physical
sciences. Hence, questionnaires should be designed to be understood by
persons without specialized technical training.
The format of the questionnaire should be as simple and as functional
as possible. When data handling is to be done by computer, time will gener-
ally be saved if the questionnaire format is such that a keypunch operator
can readily keypunch the information directly from each questionnaire. The
questions should be well spaced for easy readability with sufficient area
for complete responses. The questionnaire should be as short as possible,
because most people dislike or are intimidated by lengthy questionnaires.
Also, shorter questionnaires reduce postal costs. When preparing the ques-
tions, use terminology with which the recipient will be familiar. Each
question should be self explanatory or accompanied by clear directions. All
necessary information should be solicited on the questionnaire, thus avoid-
ing later requests for additional data. Any additional data need for
subsequent application of a photochemical model should be collected at this
same time, as well. (Volume II describes these necessary additional data.)
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Each questionnaire sent out should be accompanied by a cover letter
stating the purpose of the inventory and citing any statutes that require a
response from the recipient. The letter should include a simple explanation
of the ozone problem and relate VOC emissions to ozone formation. If the
inventory is for an ozone nonattainment area, some discussion on the impli-
cations of the nonattainment designation might be advisable. Cooperation in
filling out and returning the questionnaire should be respectfully requested.
In addition, each questionnaire should be accompanied by a set of general
procedures and instructions telling the recipient how the questionnaire
should be filled out and by what date it should be returned to the agency.
In lieu of putting a specific reply date in the cover letter, a specific
number of calendar or working days to respond can be included. In this
manner, delays in mailouts will not require the changing of the reply date
in each letter. If a general questionnaire is sent out, the instructions
should carefully explain that the questionnaire has been designed for a
variety of operations and that some questions or sections of the question-
naire may not apply to a particular facility. In all cases, a contact name,
telephone number, and mailing address should be supplied in case a recipient
has questions. The cover letter and instruction can be combined in some
cases, but this should only be done x^hen the instructions are brief. An
example cover letter and set of instructions are shown in Appendix D. A
variety of additional examples are presented in Reference 19.
When determining tha information to request on the questionnaire, the
ultimate use of the data should always be considered. In addition to general
source information, such as location, ownership, and nature of business,
correct process information should also be requested. Since activity levels,
including indicators of production and fuel consumption, are generally used
with emission factors to estimate emissions from most sources for which
source test data are not available, the appropriate activity levels must be
obtained for each type of source. The type of activity levels needed to
calculate emissions from point sources are available for most VOC emitters
in AP-42.20 In addition, since many of the emission factors in AP-42 repre-
sent emissions in the absence of any controls, control device information
should also be obtained in order to estimate controlled emissions. Control
device information is also helpful for determining potential reductions in
emissions from applying various control strategies, especially for those
source categories for which CTG documents have been published. Finally, any
information that is needed to make corrected or adjusted emission estimates
should be solicited. For example, since emissions from petroleum product
storage and handling operations are dependent on a number of variables,
including temperature, tank conditions, and product vapor pressure, appro-
priate values should be obtained for these variables that will allow the
agency to apply the correction factors given in Chapter 4 of AP-42. If
seasonal adjustments are considered, special emphasis should be given to
variables such as activity levels, temperature and windspeed that cause
seasonal variations in emissions. (Seasonal adjustment of emissions is
discussed in Chapter 6.)
Other information may be solicited in the questionnaires depending on
the agency's needs in its ozone control program. For example, stack data
such as stack height and diameter, exhaust gas temperature and flow rates
may be required for modeling purposes. Information on fuel characteristics,
3-7
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generally sulfur, ash, and heat contents, may also be desirable. Certain
compliance information may be needed if the agency is using the inventory
for enforcement purposes. Information on the nature or brand name of any
solvents is particularly helpful to the agency in excluding nonreactive VOC
from the emission totals. Process schematics, flowcharts, and operating
logs, may be requested to be returned with the questionnaire in cases where
the source is unique and/or complex. Each source should be requested to
include documented emission estimates or to enclose source test results, if
available.
An example cover letter/instruction sheet/questionnaire package aimed
specifically at obtaining information on solvent users is shown in Appendix
D. A number of the elements required in a questionnaire package are illus-
trated in this example. It should be noted that the questionnaire will not
be applicable to all major VOC emitting sources. Additional questionnaires
must be developed to cover refineries, chemical manufacturers, and other VOC
sources. Various example questionnaires dealing with many of the major
source categories are presented in Reference 19. Before adopting any ques-
tionnaires, the agency should carefully consider the objectives of the VOC
inventory in its ozone control program, and then should determine if the
data supplied in these questionnaires will meet these objectives.
Since some facilities are unique in design and operation compared to
other facilities within the same source category, it is difficult to design
questionnaires adequately to accommodate such differences and still be of
manageable size. Thus, segments of some of the questionnaires may need to
be unformatted, with the plant contact being asked to fill in whatever
information he feels is required to describe the source and its emissions.
As a rule, formatting is desirable to the maximum extent possible, because
it helps avoid confusion both to the person filling out the questionnaire
and to the agency itself. Formatting, in this context, refers to a descrip-
tion of what information is needed, the units in which the data should be
expressed, and where on the form the requested data should be located.
While questionnaires are generally tools used for obtaining point
source data, they can be used to collect certain area source data as well.
For example, many questionnaire recipients emit so little that the agency
will not want to maintain an individual record on them, but rather, will
simply group them in with an area source category such as small dry cleaning
establishments. In addition, questionnaires can be used in certain situa-
tions to directly obtain area source information. As an example, suppliers
of fuels or some kinds of solvents in an area may be contacted to get the
amount of fuel or solvent consumed collectively by residential and commer-
cial customers. Frequently, area source emissions will be determined
through other techniques, such as field surveys or the use of information
found in special publications. Area source data collection techniques are
included in Chapter 4.
3.1.4 MAILING AND TRACKING THE QUESTIONNAIRES AND LOGGING RETURNS
Once the final mailing list has been compiled and the appropriate
questionnaire packages are assembled (including mailing label, cover letter,
instructions, questionnaires, and self addressed stamped envelope), the
3-8
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agency should proceed with the mailout activities. The mailing of the
questionnaires can be performed in two ways. The first method is by regis-
tered mail, which informs the agency when a questionnaire is received by the
company. This does not guarantee that the company will return the form, but
the rate of response will probably be somewhat greater than if the question-
naires are sent by first class mail. However, the slight increase in response
may not justify the added expense of sending every company a registered
letter. As a compromise, registered mail may at least be used to contact
major sources.
The second method is to send the questionnaires by conventional first
class mail. This method has proven to be effective, if the address includes
the name of the plant manager or if "Attention: PLANT MANAGER" is printed
on the outside of the envelope. This directs the envelope to the proper
supervisory personnel and reduces the chances of the questionnaire package
being discarded. It is highly recommended that a stamped envelope be
included with each questionnaire, as it is thus more likely to be returned.
Generally, responses will start coining in within a few days after
mailing. Many of the early returns may be from companies that are not
sources of VOC emissions. Also, some of the questionnaires will be returned
to the agency by the postal service because either the establishment is out
of business or the company is no longer located at the indicated mailing
address. New addresses for companies that have moved can be obtained by
either looking up their addresses in the telephone book or contacting an
appropriate state or local agency, such as the tax or labor departments.
A simple computer program can be helpful in the mailing and logging-in
of the questionnaires. Such a program should be designed to produce a
number of duplicate mailing labels for each source sent a questionnaire.
One label is attached to the outside of the envelope containing the ques-
tionnaire materials. A second label is attached to the cover letter or
instruction sheet of the questionnaire. This facilitates the identification
of the questionnaires as they are returned, as well as name and mailing
address corrections. Additional mailing labels may be used for other admin-
istrative purposes or to recontact those sources whose responses are inade-
quate. An example label is shown below:
(SIC Code) 0000 (I.D. Code)
INDIVIDUAL'S NAME (or PLANT MANAGER)
TITLE
COMPANY NAME,
STREET,
CITY, STATE, ZIP CODE
It may be helpful to print the SIC code on the upper left and an assigned
identification number on the upper right of the labels. The ID number is
used to keep records of all correspondence with a company. If the study
area is large, a county identification number may also be included on the
mailing label.
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It is important to develop some sort of tracking system to determine
the status of each facet of the mail survey. Such a tracking system should
tell the agency: (1) which companies questionnaires are mailed to; (2) the
dates the questionnaires are mailed and returned; (3) corrected name, address,
and SIC information; (4) preliminary information on the nature of the
source; (5) whether recontacting is necessary; and (6) the status of the
followup contact effort. Tracking can be accomplished manually through the
use of worksheets o.. through the use of a simple computer program. A computer
printout of the mailing list can be formatted for use as a tracking work-
sheet.
As soon as the questionnaires are returned, some useful analyses can be
performed. One activity that can help enhance the timely completion of the
mail survey, as well as assist in estimating the amount of resources that
will be subsequently needed in the inventory effort, is to classify each
response in one of the five categories listed below:
P - VOC point source
A - VOC area source
N - No VOC emissions (non-source)
OOB - Out of business
R - Recontact for reclassification
In addition, the agency can begin performing emission calculations for those
sources that do not supply emission estimates, and the resulting source and
emissions information can begin to be loaded into the inventory files. All
responses should then be filed by SIC, source category, geographic location,
alphabetics or by any other criteria that enable orderly access for further
analysis at some later time.
3.1.5 RECONTACTING
Sources may have to be recontacted by the agency for two basic reasons:
the source may not have returned the questionnaire at all, or the response
provided may not have been adequate to meet the agency's needs. If the
source has received the questionnaire but has not returned it as requested,
it can be recontacted by a more formal letter citing statutory reporting
requirements on completing the questionnaire. When the number of sources to
be recontacted is small, the information can be obtained through telephone
contacts or plant visits. If the source refuses to complete the question-
naire (1) some sort of crude emission estimate can be made based on activity
levels or number of employees or (2) if a statute exists requiring a response,
legal action can be taken to force a response.
Recontacting activities should begin two to four weeks after the
questionnaires are mailed. Telephone calls are advantageous when recon-
tacting sources, in that direct verbal communication is involved and addi-
tional mailing costs can be avoided. Caution is urged that, when making
extensive telephone contacts, all Federal, state, or other applicable
clearance requirements are observed. A second followup mailing may be
necessary, if a large number of sources must be recontacted. In either
case, recontact should be completed 12 to 16 weeks after the first mailing.
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3.2 PLANT INSPECTIONS
In addition to the mail survey, plant inspections are another technique
commonly used to gather data for the point source inventory. During plant
inspections, agency personnel usually examine the various processes at a
particular facility and interview appropriate plant personnel. If the
agency's resources permit, source testing may be conducted as a part of the
plant inspection. Because plant inspections are generally much more time
consuming than questionnaires, they are ususally performed only at major
point sources.
Plant inspections may constitute either the initial contact an agency
has with a source or, alternately, they can be used as a method of recon-
tacting sources either to obtain additional information or to verify data
that were submitted in the questionnaire. In either case, the goal of plant
inspections is to gather source data not ordinarily obtainable through other
means. The major advantage of the plant inspection is that it may provide
more thorough and accurate information about emitters than does the question-
naire alone. In addition, errors resulting from misinterpretation of the
questionnaire, or the agency's misinterpretation of the response are avoided.
Finally, in cases where a process is unique and/or complex, the only real-
istic way for the agency to gain an adequate understanding of the emitting
points and variables affecting emissions is to personally observe the plant
equipment and to go over the operations and process schematics with the
appropriate plant personnel. However, a plant inspection should not be used
to complete a point source questionnaire at the plant site. Plant managers
and engineers usually do not have immediate access to data on equipment
specifications, process rates, or solvent purchases. Plant personnel need
time to assemble materials necessary to complete questionnaires. For these
reasons, the agency should make an appointment with the plant personnel and
provide the plant manager with questionnaires prior to an inspection.
The data that are acquired in the plant inspection are basically the
same as are solicited in a questionnaire. Generally, more data may be
obtained than would normally be requested on the questionnaire, such as
plant flow diagrams, logs of various process variables, photographs of
various emission points, and control device characteristics. Naturally, if
the plant has source tested processes within the facility, the test results
should be obtained for use in the inventory. Any source test data supplied
by a particular plant should be reviewed before they are used in the inven-
tory, to make sure that acceptable sampling and analytical procedures were
employed and that the test conditions were reasonably representative of the
time period covered by the inventory.
Special plant inspection forms may be developed to help the agency
conduct the plant visit. Because of the extra resources required, such
forms should only be developed when many plant inspections are anticipated,
when certain major sources are prevalent, and when the same kind of infor-
mation will be requested during each visit. This latter condition may not
hold in situations where the agency is using the plant inspection as a
followup to the questionnaire.
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3.3 OTHER AIR POLLUTION AGENCY FILES
During the point source data collection effort, the agency should
consider using information included in its own permit and/or compliance
files. Permits are typically required for construction, start up and con-
tinuing operation of an emission source. Of importance to the inventory
effort is the fact that permit applications generally include enough infor-
mation about a potential source to get a good idea of the nature of the
source as well as to estimate the magnitude of emissions that will result
from its operations. The inventory effort should make maximum practical use
of information in permit files. At least, the permit application file can
be used for the development of the mailing list or for determining the need
for a plant inspection or telephone contact when the source comes on line.
Another type of file that may be maintained by some agencies is the
compliance file. A compliance file is a record of the agency's dealing with
each source on enforcement matters. For example, a compliance file might
contain a list of air pollution regulations applicable to a given source, a
history of contacts made with that source on enforcement matters, and an
agreed upon schedule for the source to effect some sort of control measures.
Because the compliance file will commonly contain basic equipment information
as well as baseline emissions data, it can be a useful tool in the inventory
effort. Again, at a minimum, each source in the compliance file should be a
candidate for the emission inventory, especially if an SIC code indicates
that a source is a potential source of VOC emissions.
Permit and compliance files should both be consulted when developing
projection inventories. The information therein on proposed new facilities
or control device applications on exiting facilities will be useful to the
agency in determining baseline projection year emissions.
3.4 PUBLICATIONS
Another approach to collecting point source data is to use information
found in selected publications. The term "publication" in this context
refers to any industrial and governmental file, periodical, list, or report
that contains information on process descriptions, activity levels, or
control devices for various kinds of sources, either individually or collec-
tively. Publications are primarily used to obtain activity level infor-
mation on area sources, although to some extent, they can also be employed
for point sources. The types of reports that are available to employ this
technique include census reports, chemical business surveys, marketing
reports, trade association journals, and energy and fuel consumption reports.
As a specific example, Federal Power Commission Form 6721 contains suffi-
cient data to make estimates of VOC emissions from fossil fueled-fired power
plants. As another example, Posts Pulp and Paper Directory22 contains
equipment and production information with which to estimate approximate
emissions from pulp mills. Periodicals such as The Oil and Gas Journal23
and Chemical and Engineering News2tf intermittently list summary information
on individual refineries and chemical manufacturing operations that can also
be used to generate emission estimates. In most of these publications,
3-12
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emissions data will not be provided. Instead, emissions will have to be
estimated through the use of appropriate activity level emission factors or
emission-per-employee factors.
As a rule, emission estimates based on publications should only be used
for point sources where a questionnaire is not received, no plant contact
can be made, and for which it is necessary to get individual estimates of an
emission potential. In these circumstances, the use of publications to
obtain individual point source data should be considered a default mechanism
to be employed only if the other approaches described in this document
cannot be used. Often, the most appropriate use of such publications is to
help the agency in the development of the point source mailing list. In
certain instances, publications can be also useful in determining collective
estimates of total capacity, production, number of employees, and planned
expansion associated with particular industries. This collective infor-
mation can aid the agency in scaling up the inventory to account for missing
sources.
3.5 EXISTING INVENTORIES
Before the agency elects to employ one or several of the data gathering
approaches detailed in the previous sections, it should examine any available
inventory that may exist for the particular area of concern. If an inventory
of VOC or any other pollutant has been compiled, and either is well main-
tained or was initially well documented, many of the data elements therein
can be used directly in a new emission inventory. In many cases, the existing
point source information can be made current simply by telephone calls,
personal visits, or through the use of an abbreviated questionnaires.
Limited contacts are desirable to minimize the effort that both the source
and the agency must expend in updating the inventory data base.
If the existing inventory is computerized, a retrieval program can be
developed which prints out letters and questionnaires. The questionnaires
could contain existing inventory data on each source and could ask the
source operators to verify or to correct the information. Such a verifi-
cation form could be used with telephone contacts or plant visits. This
approach should reduce the time needed to conduct an inventory and should
ease the paper work burden of the source.
One point should be stressed if an existing inventory is employed. If
the inventory that is used as a starting point in the current effort was not
conducted primarily for VOC, a number of major VOC emitting sources may be
either omitted from such an inventory or treated collectively as area
sources because their emissions of other pollutants are negligible. Hence,
the agency should consider the possibility that additional sources may have
to be included. Conversely, there may be many sources in an existing inven-
tory that are considered major sources of some other pollutant but not
necessarily of VOC. Care should be taken in this latter instance that a
significant quantity of resources is not expended in soliciting additional
information from those sources that are not significant VOC emitters.
3-13
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References for Chapter 3.0
1. Enforceability Aspects of RACT for Factory Surface Coating of Flat
Wood Paneling, EPA-340/1-80-005, U.S. Environmental Protection Agency,
Washington, DC, April 1980.
2. Overview Starve-* of Status of Refineries in the U.S. with RACT Require-
ments , EPA Contract No. 68-01-4147, PEDCo Environmental, Inc., Dallas,
TX, 1979.
3. RACT Enforceability Aspects for Pneumatic Tire Manufacturing, EPA
Contract No. 68-01-4147, PEDCo Environmental, Inc., Arlington, TX,
March 1980.
4. Demography; Plants Subject to Phase I Surface Coating Regulations,
EPA Contract No. 68-01-4141, Research Triangle Institute, Research
Triangle Park, NC, May 1980.
5. Enforceability Aspects of RACT for the Chemical Synthesis Pharma-
ceutical Industry, EPA Contract No. 68-01-4147, PEDCo Environmental,
Inc., Cincinnati, OH, May 1980.
6. Enforceability Aspects of RACT for the Rotogravure and Flexography
Portion of the Graphic Arts Industry, EPA Contract No. 68-01-4147,
PEDCo Environmental, Inc., Cincinnati, OH, March 1980.
7. Enforcement Aspects of Reasonably Available Control Technology Applied
to Surface Coating of Miscellaneous Metal Parts and Products, EPA
Contract No. 68-01-4147, PEDCo Environmental, Inc., Cincinnati, OH, May
1980.
8. Overview Survey of the Dry Cleaning Industry, EPA Contract No. 68-01-
4147, PEDCo Environmental, Inc., Dallas, TX, March 1980.
9. Million Dollar Directory, Dun and Bradstreet, Inc., New York, NY.
10. Middle Market Directory, Dun and Bradstreet, Inc., New York, NY.
11. Industrial Directory, Dun and Bradstreet, Inc., New York, NY.
12. National Business Lists, Inc., 162 N. Franklin St., Chicago, IL.
13. Craig Colgate, Jr., ed., National Trade and Professional Associations
of the United States and Canada and Labor Unions, Fifteenth Edition,
Columbia Books, Inc., Washington, DC, 1980.
14. Nancy Yanes and Dennis Akey, eds., Encyclopedia of Assoications,
Volumes 1-3, Fourteen Edition, Gale Research Company, Detroit, MI,
1980.
3-14
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15. Standard Industrial Classification Manual, Executive Office of the
President, Office of Management and Budget, Washington, DC, 1972.
16. P. Di Gasbarro and M. Borstein, Methodology for Inventorying Hydro-
carbons , EPA-600/4-76-013, U.S. Environmental Protection Agency,
Research Triangle Park, NC, March 1976.
17. Lew Heckmen, "Organic Emission Inventory Methodology for New York and
New Jersey", Presented at the Emission Inventory/Factor Workshop,
Raleigh, NC, September 13-15, 1977.
18. Procedures for the Preparation of Emission Inventories for Volatile
Organic Compounds, Volume II, EPA-450/4-79-018, U.S. Environmental
Protection Agency, Research Triangle Park, NC, September 1979.
19. Development of Questionnaires for Various Emission Inventory Uses,
EPA-450/3-78-122, U.S. Environmental Protection Agency, Research
Triangle Park, NC, June 1979.
20. Compilation of Air Pollution Emission Factors, AP-42, 3rd Edition and
subsequent supplements, U.S. Environmental Protection Agency, Research
Triangle Park, NC, August 1977.
21. "Steam-electric Plant Air and Water Quality Control Data for the Year
Ended December 31, 19 ", Federal Power Commission Form 67.
22. Post's Pulp and Paper Directory, Miller Freeman Publications, Inc.,
500 Howard Street, San Francisco, CA.
23. Oil and Gas Journal, Petroleum Publishing Co, 1021 S. Sheridan Road,
Tulsa, OK. Weekly.
24. Chemical Engineering News, American Chemical Society, Washington, DC.
3-15
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4.0 AREA SOURCE DATA COLLECTION
4.1 INTRODUCTION
The area source inventory enables an agency to estimate emissions
collectively for those sources that are too small and/or too numerous to be
handled individually in the point source inventory. Considerable attention
should be given to the area source inventory, as significant quantities of
VOC emissions will generally be associated with the important area source
categories. Historically, emissions from area sources have been underesti-
mated because of either the lack of appropriate inventory procedures or
little emphasis on obtaining area source data. This chapter provides
several approaches to collecting data at the county or equivalent level,
from which annual or seasonal area source estimates can be derived. In
addition, procedures are presented to account for emissions from source
categories which have been often overlooked in previous VOC emission
inventories.
4.1.1 AREA SOURCE INVENTORY STRUCTURE AND EMPHASIS
Table 4.1-1 lists those categories that are primarily inventoried as
area sources in a VOC emission inventory. Sources listed in Table 2.2-1
which are not in Table 4.1-1 and are below the point source inventory cutoff
can also be collectively tabulated and reported as area sources. The impor-
tance of area source categories may vary from area to area. In certain
areas, other sources of local importance may need to be included, or addi-
tional subcategories may need to be defined. The area source categories in
Table 4.1-1 can be divided into two broad groups characterized by the emis-
sion mechanism: (1) evaporative emissions and (2) fuel combustion emissions.
Most evaporative emission sources with the exception of service stations,
are characterized by some type of solvent use. Service stations emit gaso-
line vapors as a result of various loading and fueling operations.
As is discussed in more detail in subsequent sections of this chapter,
some of the source categories in Table 4.1-1 will usually be handled entirely
as area sources. However, some source categories will be handled only
partially as area sources if a portion of the facilities in a category is
large enough for individual treatment as point sources. It is important in
this latter case that care be taken not to double count sources emissions in
both the point and area source inventories. Area source emission totals
should be adjusted downward to reflect emissions accounted for in the point
source inventory.
The selection and structuring of area source categories is an important
aspect of the planning process that affects the resources required for
inventory completion as well as the inventories usefulness in the agency's
ozone control program. Generally, highway vehicles will be the largest VOC
emitting category and should be emphasized accordingly. All of the evapor-
ative loss sources may be important, especially those covered by Control
Techniques Guidelines. Special attention should be given to these VOC
sources as well.
4-1
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Table 4.1-1. Area Sources of VOC Emissions.
Evaporative Loss -
Gasoline Service Stations (and other outlets)
- Tank truck unloading (Stage I)
- Vehicle fueling (Stage II)
- Storage tank breathing losses
Solvent Users
- Degreasing, small industrial/commercial
- Drycleaning
- Surface coatings
Architectural
Auto body refinishing
Other small industrial
- Graphic arts
- Commercial/consumer solvent use
- Cutback asphalt
- Pesticides
Combustion —
Highway Mobile Sources
- Light duty vehicles (LDV)
- Light duty gasoline powered trucks <6000 Ibs (LDT1)
- Light duty gasoline powered trucks 6000-8500 Ibs (LDT2)
- Heavy duty gasoline powered trucks (HDG)
- Heavy duty diesel powered trucks (HDD)
- Motorcycles
Stationary Source Fossil Fuel Combustion (by fuel type)
- Residential
- Commercial/institutional
- Industrial
Non-highway Mobile Sources
- Aircraft (Military, civil, commercial)
- Railroad locomotives
- Vessels
- Off highway vehicles
Solid Waste Disposal
- On site incineration
- Open burning
- Structural fires
- Field/slash/forest fire burning
4-2
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Because an important use of the inventory is to study the effects of
applying various control measures, the area source categories should be
defined so that emission reductions from anticipated controls on area
sources can be readily summarized from the data maintained in the area
source files. For example, if the effect of vapor recovery on tank truck
unloading emissions at service stations (Stage I control) is to be evalu-
ated, then these operations should be distinguished from vehicle fuel tank
loading (Stage II operations) emissions. As another example, in order to
estimate the effect of RACT on dry cleaning plants, those systems using
perchloroethylene should be maintained separately from those using petroleum
(Stoddard) solvents because of the different control technologies that may
be applied to each system. Judicious definition of area source categories
will also help the agency exclude nonreactive compounds from the emission
totals. In this regard, if separate emission totals are maintained for
different solvents in the inventory, most of the nonreactive halogenated
solvents can be readily identified.
4.1.2 SOURCE ACTIVITY LEVELS
Area source emissions are typically estimated by multiplying an emis-
sion factor by some known indicator of collective activity for each source
category at the county (or equivalent) level. An activity level is any
parameter associated with the activity of a source, such as production or
fuel consumption, that may be correlated with the air pollutant emissions
from that source. For example, the number of landings and takeoffs (LTO)
provides an estimate of aircraft activity at an airport. In this example,
the number of LTOs can be multiplied by appropriate emission factors to
estimate airport emissions. As another example, the total amount of gasoline
handled by service stations in an area can be used to estimate evaporative
losses from gasoline marketing. In this case, to estimate total emissions
from this source category, the gasoline handling activity can be multiplied
by an emission factor representing all of the individual handling operations
at each service station.
4.1.3 METHODS FOR ESTIMATING AREA SOURCE ACTIVITY LEVELS AND EMISSIONS
Several methodologies are available for estimating area source activity
levels and emissions. Estimates can be derived by (1) treating area sources
as point sources, (2) surveying local activity levels, (3) by apportioning
national or statewide activity totals to local inventory areas, (4) using
per capita emission factors and (5) emissions-per-employee factors. Each
approach has distinct advantages and disadvantages when used for developing
emissions estimates, as discussed below.
1. Applying point source methods to area sources - Small sources that
would normally be treated as area sources may be handled as point sources
for several reasons. First, collective activity level estimates may not be
readily determinable for certain source categories. Bulk plants are an
example of this. According to the CTG summary in Appendix C, a typical
gasoline bulk plant emits only 17 tons of VOC per year. This emission rate
would normally be below the agency's point source cutoff level. However,
because the area source procedures used for determining gasoline sales in an
4-3
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area will probably not yield an estimate of the amount of gasoline trans-
ferred through bulk plants, the agency may need to elicit this information
from each plant by using point source procedures.
In other cases, sufficient data may be available on individual sources
to allow the agency to estimate activity levels and emissions for each
facility. For example, records may be available from another agency that
show the location and amount of solvent handled by each dry cleaner within
the inventory area, in which case the inventorying agency may calculate
emissions for each plant. At this point, the agency must decide whether an
individual point source record will be coded and maintained for each facil-
ity or whether the resulting individual activity levels and emission esti-
mates will be collectively handled in the area source inventory. This
decision will depend on (1) the resources available for the point source
inventory and (2) whetfrer the agency elects to handle sources individually
or collectively in the projection year inventory. In this latter regard,
more accurate projections will result if sources aie treated as point sources,
because individual control reductions can be estimated for each facility.
2. Local activity level surveys - In some instances, collective
activity level estimates for a given catgory may be available from a local
source. For example, local trade associations may have data on the amount
and types of architectural surface coating, or the amount and types of dry
cleaning solvents used in an area. Tax, highway, energy, and other state or
local agency records may provide collective activity level estimates for
other area source categories, including gasoline sales or cutback asphalt
use. Hence, the inventorying agency should survey various local associ-
ations and agencies to determine what information is maintained for the area
that can be used in the area source inventory. Specific associations or
agencies that may be contacted for selected area source activity level
information are suggested in the following sections of Chapter 4.
3. Apportioning state or national totals to the local level - If
countywide activity level information is not available locally, state
totals may be apportioned to compute local estimates. For example, the
quantity of fuel used in railroad locomotives is generally available at the
state level from the Bureau of Mines. Fuel use can be approximated at the
local level by apportioning statewide fuel use to the county level on the
basis of miles of track per county. Residential, commercial, and industrial
fuel combustion are other categories that are commonly handled in this
manner. Major drawbacks of this approach are that additional data and
resources are needed to apportion activity level estimates to the local
level, and accuracy is lost in the process. If state level data are not
available and no alternatives are accessible, then national data may have to
be apportioned to the local inventory area. However, apportioning national
data to the local level is generally less accurate than most available
methods and should be done only when absolutely necessary.
The National Air Data Branch of EPA uses state and national totals from
various available publications to estimate area source emissions at the
county level for NEDS. Those interesed in obtaining NEDS emission estimates
for particular area sources in specific counties should contact their EPA
Regional Office or the National Air Data Branch, MD-14, U.S. Environmental
4-4
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Protection Agency, Research Triangle Park, NC 27711. In general, these NEDS
area source estimates will not be as sensitive to local conditions as esti-
mates made by an agency using locale-specific information. The techniques
used in NEDS for developing area source estimates are described in References
1-3.
4. Per capita emission factors - Sources in certain area source
categories are not only numerous and diffuse, but are difficult to inventory
by any of the above procedures. As an example, solvent evaporation from
consumer and commercial products as waxes, aerosol products and window
cleaners neither can be routinely determined by the local agency from any
local sources nor will any kind of survey generally be possible that will
yield such information. The use of per capita factors is based on the
assumption that, in a given area, emissions can be reasonably associated
with population. This assumption is valid over broad areas for certain
activities such as drycleaning, architectural surface coating, small degreas-
ing operations and solvent evaporation from household and commercial products.
Per capita factors for these categories are suggested in the following
sections of this chapter. Per capita factors should not be developed and
used indiscriminately for sources whose emissions do not correlate well with
population. Large, concentrated industries, such as petrochemical facilities,
should not be inventoried by per capita factors.
5. Emissions-per-employee factors - This approach is conceptually
equivalent to using per capita factors, except that employment is used as a
surrogate activity level indicator rather than population. Emissions-per-
employee factors are usually used to estimate emissions for those source
categories for which a Standard Industrial Classification code has been
assigned and for which employment data (typically by SIC) at the local level
are available. Generally, this involves SIC categories 20-39, as shown in
Table 3 of Chapter 3. Since, in most cases, a large fraction of VOC emissions
within SICs 20-39 will be covered by point source procedures, the emissions-
per-employee factor approach can be considered a back up procedure to cover
emissions from sources that are below the point source cutoff level. This
approach can also be used where the agency only surveys a fraction of the
area sources within a given category. In any case, employment is used as an
indicator to "scale up" the inventory to account collectively for missing
sources and emissions in the area source inventory. Parameters other than
employment, such as sales data or number of facilities can be used to
develop emission estimates. However, employment is generally the most
readily available parameter. Scaling up is discussed in detail in Chapter
6.
4.1.4 CONTENTS OF CHAPTER 4
The remainder of this chapter discusses specific methodologies that may
be used to determine emissions for the more important source categories
shown in Table 4.1-1, except for highway vehicles. Chapter 5 is entirely
devoted to a discussion of highway vehicle inventory procedures. In each
case, alternative approaches are presented that vary in complexity, cost,
and in the accuracy of the resulting emission totals. Although certain
approaches may be recommended, local data may suggest the use of a alter-
native procedures in a given situation.
4-5
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4.2 GASOLINE DISTRIBUTION LOSSES
A generalized flowchart of gasoline marketing operations is shown in
Figure 4.2-1. This flowchart depicts the operations typically involved in
transporting gasoline from refineries to final consumption in gasoline
powered vehicles. As indicated in Figure 4.2-1, evaporative emissions occur
at all points in the distributive process. The operations generally inven-
toried as area souses are (1) gasoline dispensing outlets and (2) gasoline
tank trucks in transit. Bulk terminals and gasoline bulk plants, which are
intermediate distribution points between refineries and outlets, are usually
inventoried as point sources.^ Diesel fuel is excluded from consideration
due to its low volatility.
VOC emissions from gasoline dispensing outlets result from vapor
losses during (1) tank truck unloading into underground storage tanks, (2)
vehicle fueling, and (3) underground storage tank breathing. When inven-
torying evaporative losses from this source category, each of these activ-
ities should be tabulated separately, so that various control reduction
measures may be readily evaluated. EPA has made available Control Techniques
Guidelines (CTG) for Stage I operations covering gasoline vapors emitted
during storage tank filling.5
Service stations are the primary retail distributors for gasoline.
Gasoline also can be purchased from other types of businesses or stores,
such as auto repair garages, parking garages, and convenience stores. In
addition, gasoline may be distributed to vehicles through various non-retail
outlets. Because outlets other than service stations account for roughly a
quarter of all gasoline handled, care should be taken that they are covered
in the area source inventory.^>5
4.2.1 DETERMINING GASOLINE SALES
Area source gasoline evaporative losses can be inventoried in several
ways. The most accurate approach is to acquire gasoline sales data which
can be multiplied by a composite emission factor to determine evaporative
losses. Gasoline sales statistics are collected and maintained by petroleum
distributors and state motor vehicle and fuel tax offices, as well as
federal and local government agencies involved in transportation planning
and energy management. The statistics are developed from delivery records
which are collected from drivers, compiled, and sent to petroleum company
accounting offices. These statistics are summarized by county or other
local political jurisdiction and are forwarded to the state tax office.
Thus, as the tax is collected per gallon sold, the actual total gasoline
consumption within a jurisdication can be back calculated with the tax
formulas. Calculation of fuel consumption from fuel tax data may already be
done in some transportation planning agencies. Once derived, tax-calculated
consumption should be cross checked with data from associations of service
station owners and operators, oil company distributors jobbers and other
local sources.7 Cross-checking is important, since gasoline for non-highway
uses and gasoline distributed to government agencies may not be taxed.
Therefore, care should be taken that all gasoline consumed in the inventory
area is accounted for, including that dispensed at marinas, airports,
military bases, and government motor pools, as well as service stations.
4-6
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FACILITY GASOLINE FLOW
cc
111
_J
0.
03
Miscellaneous
End Users
T
O
CO
z
LU
O.
CO
1
Storage Tank
(Floating/Fixed
Roof)
Loading Rack
Tanker Truck
(Area)
Storage Tank
(Fixed Roof)
Loading Rack
Truck
Storage Tank
(Underground)
Pump
Vehicles
Transport Out of
Inventory Area
Transport From
Other Areas
Transport Out of
Inventory Area
Transport From
Outside Inventory
Area
VOC
EMISSION
SOURCES
Standing
Breathing'
Transfer.
Transport •
Transfer -
Breathing •
Transfer —
Breathing-
Dispensing-
Point
—Source
Inventory
Area
— Source
Inventory
Figure 4.2-1. Gasoline Marketing Operations and Emission Sources4.
4-7
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Gasoline distributors may be able to provide consumption data on these
sources. However, direct contact with a possible source is often the only
viable way to determine gasoline consumption from these non-highway sources
of gasoline evaporation. Also, when using fuel tax data to determine
gasoline consumption, diesel fuel and any other fuel of low volatility
should be excluded from consideration.
Several less desirable alternatives exist for obtaining estimates of
gasoline sales in an area. Questionnaires have been used in some instances
as a means of obtaining information on each facility. Information collected
in such a questionnaire could include not only the quantity of gasoline
which is dispensed over a given year or season, but also the type of equip-
ment use and the number of employees at the station. While this type of
direct plant contact is potentially more accurate, because information can
be determined on the type of filling and the existence of controls at each
station, the use of questionnaires does involve several drawbacks. A major
obstacle is the sheer number of stations usually present in most areas. In
addition, because of the rapid rate at which stations open and close or
change locations, a current list of sources may be difficult to define.
Moreover, since many stations invariably will not respond to the question-
naires, the inventory will have to be scaled up to account for the missing
stations. If questionnaires are used, scaling up can be accomplished using
either employment in SIC 5541 or the number of gasoline stations as a
indicator of coverage. Scaling up is discussed in Section 6.4.
Contacting distributors of gasoline through questionnaries or telephone
calls has been discussed as a possible method of checking gasoline consump-
tion obtained through tax records. However, while contacting distributors
is a direct source of consumption data, it can be difficult if there is (1)
a large number of distributors, (2) distribution areas which overlap the
inventory boundaries, or (3) a lack of cooperation by the distributors.
Fuel tax data should be easier to obtain in most areas and is therefore
preferred over a method which involves contacting gasoline distributors.
Another less desirable alternative for estimating gasoline consumption
is to use data from various national publications. For example, FHwA's
annual publication, Highway Statistics, contains gasoline consumption data
for each state.8 Countywide estimates can be determined by apportioning
these statewide totals by the percent of state gasoline station sales
occuring within each county. Countywide service gasoline sales data are
available from the Census of Business Retail Trade.9 (Note: Data in Retail
Trade are usually too old to use directly in estimating countywide sales;
however, they are useful in allocating other data to the county level.)
Other apportioning variables, such as registered vehicles or VMT, can be
used if the local agency feels that they result in a more accurate distri-
bution of state totals at the county level. These apportioning procedures
are used in EPA's National Emissions Data System (NEDS) to estimate emissions
for gasoline service stations. Even if the agency uses local sales data in
the area source inventory, this approach should be used as a cross check of
the local consumption estimates. One distinct advantage of using data in
Highway Statistics is that sales are tabulated by month, thus facilitating a
seasonal adjustment of the gasoline station emission totals.
4-8
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Another alternative for estimating gasoline sales is to use VMT data
available as a result of the ongoing transportation planning process. This
alternative is not generally recommended for several reasons. First, it
requires local information on both the percent of VMT attributable to
diesel versus gasoline fuel and the average miles-per-gallon fuel efficiency
of the gasoline powered motor fleet. None of these data may be available
locally, and the use of nationwide averages may introduce errors in certain
applications. Moreover, highway travel will not account for all gasoline
sold at various outlets. Some fraction of the gasoline is consumed in
various off-highway applications. Hence, because less data intensive and
more accurate procedures are usually available in any area to estimate
gasoline sales, the VMT based approach generally should not be considered.
Using state or local air pollution permit files for inventorying
gasoline dispensing outlets is not likely to be an effective alternative.
Permit information is not usually collected because of the large number of
stations and because each stations's emissions are much lower than tradi-
tional point source cutoff levels. Registration systems are being attempted
inrsome states whereby major retail chains are required to compile and
submit service station lists.6 Generally, such a detailed approach is not
warranted when gasoline distribution data will yield adequate emission
estimates.
4.2.2 ESTIMATING GASOLINE DISTRIBUTION EMISSIONS
Whatever approach is used to account for gasoline consumption, the flow
of gasoline throught the inventory area should be mapped. The best approach
is to develop a chart depicting overall gasoline flow within the geograph-
ical area in question, from the point of entry, through bulk storage, to
service stations and vehicle loading operations. Figure 4.2-1 can serve as
the basis for such a flowchart. Construction of this flow chart provides a
valuable overview of the gasoline distribution system and facilitates
detection of gross anomalies in the distribution data.
Once an estimate of total gasoline sales is made, gasoline dispensing
emissions can be estimated using the average emission factors shown in
Section 4.4 of AP-42.10 To facilitate the subsequent development of control
strategy estimates, separate subcategories should be maintained for (A) tank
truck unloading, (B) vehicle fueling, (C) underground tank breathing losses,
and (D) tank truck transit losses. When evaluating control scenarios, tank
truck unloading and vehicle refueling are defined respectively as Stage I
and Stage II controls. A detailed description of gasoline marketing
operations is available in Reference 4.
4.2.2.1 Tank Truck Unloading (Stage I)
Emissions from tank truck unloading are affected by whether the service
station tank is equipped for submerged, splash or balance filling. There-
fore, information must be obtained on the fraction of stations using each
filling method. A weighted average emission factor can then be based on the
quantity of gasoline delivered by each method. A survey of several service
stations in the area will produce an estimate of the number of stations
4-9
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employing each filling method. Trade associations are another source of
information on station characteristics. Information from major brand owner/
operators may also be readily available but should be used with care, as
company policy may direct the use of certain equipment not representative of
all stations within an inventory area. Recent studies in two U.S. cities
suggest that 70 to 95 percent of service stations are equipped for submerged
filling, with the remainder employing splash filling.11"14 Balanced filling,
(Stage I vapor rec very), is employed at very few of the stations in these
study areas. Caution is urged when adapting these percentages, because they
may change rapidly in the direction of more submerged filling and balanced
filling. Hence, use of current, local data are recommended.
4.2.2.2 Vehicle Fueling and Underground Tank Breathing
Losses from vehicle fueling, including spillage, and from underground
tank breathing are determined by multiplying gasoline throughput by the
appropriate AP-42 emission factors. Gasoline sales data can be used as a
collective measure of gasoline throughtput. Determining which service
stations have vehicle refueling (Stage II) emissions controls is important
in projection year inventories. If Stage II controls are planned in a
projection year, a composite emission factor will have to be determined
representing the mix of controlled and uncontrolled refueling operations in
the area. At present, Stage II controls are not widely implemented. Under-
ground tank breathing may be affected by Stage II controls but are unaffected
by Stage I controls.^
4.2.2.3 Losses from Gasoline Tank Trucks in Transit
Breathing losses from tank trucks during the transport of gasoline are
caused by leaking delivery trucks, pressure in the tanks, and thermal
effects on the vapor and on the liquid. A worst case situation arises if a
poorly sealed tank has been loaded with gasoline and pure air becomes
saturated. During the vaporization process, pressure increases and venting
occurs.
Emission factors for gasoline trucks in transit are given in Section
4.4 of AP-42. These factors are given in terms of lb/103 gallons of gasoline
transferred in two modes: (1) tanks loaded with fuel and (2) tanks returning
with vapor. For convenience, these factors may be added and applied to each
round trip delivery.
Because some gasoline is delivered to bulk plants rather than delivered
directly to service stations from bulk terminals, the amount of gasoline
transferred in any area may exceed the total gasoline consumption, due to
the additional trips involved. Emissions should be based on total gasoline
transferred rather than on consumption. As an example, if gasoline sales in
an area are 300 million gallons per year, and 50 million gallons of this
goes through bulk plants, then 350 million gallons is transported by tank
truck and is the appropriate figure to use to estimate transit losses. As
a nationwide average, roughly 25 percent of all gasoline consumed goes
through bulk plants.11 Hence, gasoline distribution in an area could be
multiplied by 1.25 to estimate gasoline transported. Because this percent-
age will vary so much from area to area, the amount of gasoline handled by
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bulk plants should be obtained from the point source inventory and be used
in making this adjustment. Emissions from this source will generally be
minimal in most areas. Hence, a great deal of effort is not warranted in
making this adjustment.
4.3 STATIONARY SOURCE SOLVENT EVAPORATION
Solvents are any liquid organic compounds (or groups of compounds) that
are used to dissolve other materials. Solvent use can be broadly classified
into two categories: (1) cleaning, including degreasing and drycleaning,
and (2) product application, such as surface coating, printing, and pesti-
cides, where the solvent serves as a vehicle for the product being applied.
Each of these two types of solvent use results in some or all of the solvent
being evaporated into the atmosphere.
The widespread use of solvents in all sectors of the economy makes
inventorying VOC emissions a difficult task. The most accurate means to
account for solvent use in the inventory is to identify as many sources as
possible using the point source methods in Chapter 3. Unfortunately,
because so many small solvent users are present in most, especially urban,
areas, all of these small sources cannot be economically handled as point
sources. Hence, area source procedures are necessary to include these small
solvent users in the VOC inventory. The source categories covered in
Section 4.3 are shown in Table 4.1-1. In certain areas, other solvent
evaporation sources may be of local importance, and should be included in
the area source inventory.
4.3.1 DRY CLEANING
Dry cleaning operations vary in size, type of service, and type of
solvent used. Industrial, commercial, and self service facilities clean not
only personal clothing, but also uniforms, linens, drapes, and other fabric
materials. Three basic solvent types are used in drycleaning: petroleum
(Stoddard), perchloroethylene ("perc"), and trichlorotrifluoroethane (Freon
113). Perchloroethylene is used in approximately 80 to 90 percent of all
dry cleaning establishments and constitutes about 70 percent of all cleaning
solvent consumed. Almost all other establishments use petroleum solvent.
Fluorocarbons represent only a small percentage of dry cleaning solvent
use.15'18
VOC emissions from drycleaning vary with the type of process and
solvent used. Perchloroethylene systems emit less VOC for a given quantity
of clothes cleaned due to the higher cost of synthetic solvents, while
petroleum solvent operations typically have greater evaporative losses. VOC
emissions occur mainly from the dryer and the filter muck treatment systems.
Miscellaneous fugitive losses occur from valves, flanges and seals as a
result of poor maintenance. Detailed process descriptions and information
on emissions and controls can be obtained from References 16 and 17 as well
as AP-42.
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Both point and area source methods can be used to inventory dry cleaners.
Industrial dry cleaning is done at large plants whose emissions will usually
exceed 100 tons of VOC per year and should be inventoried by point source
procedures described in Chapter 3.
Commercial and self service dry cleaning facilities typically emit less
than 10 tons per year and large numbers of these facilities may operate
within an urban area. A number of area source methods may be used in conjunc-
tion with point source procedures to inventory commercial and self service
dry cleaning emissions. Optimally, all plants may be handled using point
source procedures. The easiest way to accomplish this is to send brief
survey forms to each plant or to a representative sample of plants identified
in the yellow pages of the telephone directory. An example of such a form
is shown in Appendix D. In general, all that is needed to develop an area
source emission total from such a survey is information on the quantity of
solvent annually consumed at every plant below the point source cutoff
level. Emissions are assumed equal to the total quantity of makeup solvent
consumption in the area. Information should also be obtained on the type of
solvent used at each plant and on any control measures in place. If inciner-
ation is practiced at any petroleum plant, emissions from that plant will
not equal to makeup solvent consumption, but rather, will be reduced accord-
ing to the efficiency of the control device. In contrast, when the more
common nondestructive control measures are employed, such as condensers and
adsorbers, emissions approximate makeup solvent consumption, because the
collected solvent is cycled for reuse in the process. Because the agency
may elect to send questionnaires to only a sample of dry cleaners below the
cutoff level, the resulting emission totals from the point source inventory
and the area source survey should be scaled up to account for missing emis-
sions. Scaling up should be based on (1) employment within SICs 7215, 7216,
and 7218 or (2) number of plants covered by the point source survey. If employ-
ment is used as the coverage indicator, the survey form should also ask for
the number of employees working at each plant. Scaling up is discussed in
detail in Chapter 6.
As a recommended alternative to handling all dry cleaners as point
sources the following factors may be applied to estimate nonindustrial dry
cleaning emissions within a broad area:
Commercial plants: 1.2 Ib/capita-yr
Self service (coin-op) plants: 0.3 Ib/capita-yr
If any commercial or coin-op plants are known to be included in the point
source inventory, the emission estimates resulting from the above per capita
factors must be reduced accordingly. About 30 percent of the above per
capita factor for commercial plants represents petroleum solvent whereas the
remaining 70 percent of the commercial plant solvent and all of the coin-op
solvent are perchloroethylene. The use of trichlorotrifluoroethane can be
assumed to be nominal when applying these per capita factors.
The following example illustrates the use of these factors.
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Example; An urban area with an inventory base year population of
1,032,500 people has been inventoried by questionnaires sent
mainly to large industrial dry cleaning plants. The question-
naires identified an industrial dry cleaning plant using
petroleum solvent of which 102 tons were emitted during the
base year. Fifteen commercial dry cleaning plants were also
identified, emitting a total of 105 tons of perchloroethylene
and petroleum solvents.
Solution: Total commercial and self service plant emissions can be
estimated by applying a per capita emission factor, as
follows:
1,032,500 x (1.2 + 0.3) Ib VOC x 1 ton = 774 tpy
capita _yr 2000 Ib
Since 105 tons/yr of this 774 tons/yr are accounted for
in the point source inventory, the resulting area source
total for commercial and coin-op plants is:
(774 - 105) = 669 tons/yr
Hence, total dry cleaning emissions for the area are:
669 + 105 + 102 = 876 tons/yr
Note in this example that the commercial plant point source total is
subtracted from the per capita derived emissions. Also, the industrial
plant point source emissions are not subtracted from per capita emissions.
Finally, note that these factors apply only to perchloroethylene and
petroleum solvent emissions.
A small percentage of dry cleaning establishments uses trichlorotri-
fluoroethane (fluorocarbon 113) as a fabric cleaning solvent. Fluorocarbon
113 is classified by EPA as a nonreactive compound. Therefore information
on the type of solvent used at each dry cleaning plant needs to be elicited
during any plant contacts or surveys so that fluorocarbon 113 emissions can
be directly excluded. Nationwide, fluorocarbon 113 is only used in about 5
percent of the coin operated units, accounting for only about 0.4 percent of
total annual dry cleaning solvent consumption.16 Hence, in most situations,
little error is involved if all dry cleaning solvent is assumed to consist
of perchloroethylene and petroleum solvents. The per capita factors recom-
mended earlier exclude fluorocarbon 113.18
4.3.2 DECREASING OPERATIONS
Solvent metal cleaning or degreasing operations employ nonaqueous
solvents to remove soils from the surface of metal articles which are to be
electroplated, painted, repaired, inspected, assembled, or machined. Metal
workpieces are cleaned with organic solvents in applications where water or
detergent solutions cannot do an adequate cleaning job. A broad spectrum of
organic solvents may be used for degreasing, such as petroleum distillates,
chlorinated hydrocarbons, ketones and alcohols.
4-13
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There are basically three types of degreasers: small cold cleaners,
open top vapor degreasers, and conveyorized degreasers. According to
recent estimates, there are about 1,300,000 small cold cleaning units
operating in the U.S. Seventy percent of these units are devoted to main-
tenance of servicing operations, including service stations, auto dealer-
ships, and miscellaneous repair stations, while the remaining 30 percent are
devoted to manufacturing operations. A typical cold cleaning unit emits
approximately one uhird metric tons of VOC per year. In contrast, typical
open top vapor degreasers and conveyorized degreasing units emit respectively,
on average, 10 and 27 metric tons of VOC per year. These larger units are
commonly used in the metal working industry. The design and operation of
each of these types of degreasers will vary, as will emissions and the types
of control measures used. References 16 and 20 should be consulted for
detailed descriptions of processes and emissions from degreasing units.
Development of degreasing emission estimates is complicated by a number
of factors. First, some degreasers will be large enough to be considered
point sources, and yet, a large fraction of all degreasers will fall below
any reasonable point source cutoff and thus will have to be tallied as area
sources. Second, degreasing operations are not associated with any partic-
ular industrial activity. Instead, degreasing of some sort may be carried
out in a wide variety of industries, including (1) metal working facilities
(e.g., automotive, electronics, appliances, furniture, jewelry, plumbing,
aircraft, refrigeration, business machinery, fasteners), (2) non metal
working facilities (printing, chemicals, plastics, rubber, textiles, glass,
paper, electric power), (3) maintenance cleaning operations (electric
motors, fork lift trucks, printing presses), and (4) repair shops (auto-
mobile, railroad, bus, aircraft, truck, electric tool). Third, the practice
of solvent waste reprocessing at some degreasing facilitites complicates the
making of material balance estimates of solvent loss. Fourth, the fact that
much of the VOC emissions associated with degreasing occurs at the solvent
waste disposal site complicates the location of emissions within the inven-
tory area. Fifth, many of the solvents used for degreasing are considered
photochemically nonreactive, and hence, must be excluded from the inventory
totals.19,20
A general chart of degreasing solvent flow in an area is shown in
Figure 4.3-1. Ideally, the agency could develop an areawide estimate of
total degreasing emissions from both point and area sources from the totals
in this flowchart. Basically, total areawide emissions would approximately
equal the amount of solvent purchased by degreasers minus that quantity of
solvent sent to commercial reprocessing plants for reclamation. In practice,
such a flowchart may be difficult to construct for several reasons. First,
manufacturers, distributors and commercial reprocessors may be reluctant to
disclose sales information. Second, they may not know how much of their
product is used for degreasing as opposed to other end uses. Third, they
may be unable to determine where their product is used, especially if they
are not the final distributors in the area, or if they are selling to
companies located at a number of sites. Fourth, some fraction of degreasing
solvent most likely will be shipped from outside the inventory area.
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I k (B) Emissions
Uncontrolled
Emissions
Fraction
New
Solvent
Distributors of
Degreasing
Solvents
Solvent Reclaimed
by Reprocessor
Purchased
Solvent
Destructive
Controlled
Emissions
Fraction
Uncontrolled
Emissions
Fraction
Degreasing Including
Cold Cleaning
and Vapor Degreasing
Distillation
(A) Emissions
Destructive
Controlled
Emissions
Fraction
Uncontrolled
Emissions
Fraction
Unrecoverable
Solvent and
Solvent
Containing
Waste
(C) Emissions
Destructive
Control or
Permanent Capture
Emissions Fraction
Waste Solvent
Disposal
Open Storage
Landfills and Dumps
Incineration
Deep Well Inject
Used Solvent
Sold to
Reprocessor
Reprocessor
Wastes
Containing
Solvent
Residue
Solvent
Reprocessor
New Solvent Purchased Reprocessed
Total Degreasing Emissions = (A + B + C) = S Produced for = 2 Degreasing - 2 Degreasing
Degreasing Solvent Solvent
Figure 4.3-1. Mass Balance of Solvent Used in Degreasing Operations.
-------
Hence, while a valuable concept in understanding degreasing emissions, and
a possibility in some circumstances, such a flowchart is not considered
practical in most areas.
4.3.2.1 Open Top Vapor and Conveyorized Degreasing
Open top vapor degreasers and conveyorized degreasers should be handled
as point sources to the extent possible, even though these units individually
may not exceed the agency's point source cutoff level. General point source
procedures are covered in Chapter 3. A questionnaire covering degreasing
emissions is shown in Appendix D. Likewise, solvent reprocessing plants
should be handled as point sources. Major advantages of handling these
larger operations as point sources are that source-specific data can be
elicited on the amounts and kinds of solvents consumed at each facility, as
well as on the amounts of waste solvent sold for reprocessing or disposal by
some other means. With this kind of detailed information, material balances
can be employed to estimate degreasing emissions from each unit.
Because all open top vapor degreasers and conveyorized degreasers may
not be covered in the point source inventory, procedures should be con-
sidered for scaling up to account for missing emissions. As discussed in
Chapter 6, scaling up is best accomplished using employment data in appro-
priate SIC codes as indicators of inventory coverage. Hence, to encompass
missing open top vapor degreasers and conveyorized degreasers, the agency
should scale up the inventory in SIC categories 25 and 33 through 39.
Because comprehensive emissions-per-employee factors are not available from
the literature for scaling up emissions in degreasing operations, the agency
will have to develop its own emissions-per-employee factors from the point
source data obtained through plant contacts. Specifically, for each SIC
code for which degreasing activities are carried out in the local area, the
ratio of reported emissions to reported employment should be calculated and
multiplied by total employment for each SIC code, as shown in Equation 6.4-2
in Chapter 6. This results in an estimate of area total emissions associated
with open top vapor degreasing and conveyorized degreasing operations. The
area source component is determined by subtracting reported point source
emissions from this total. This process is repeated for each SIC associated
with degreasing emissions.
If the agency chooses to scale up the open top vapor and conveyorized
degreasing emissions in the above manner, several points should be first
noted. First, the need for scaling up should be reviewed. The agency may
have made such extensive plant contacts that all open top vapor degreasers
and conveyorized degreasers are adequately covered as point sources. One
way to check this is to compare the reported employment in SICs 25 and 33
through 39 (as determined from the point source records) with the total
employment in the county for each SIC. The latter figures are available in
Reference 21. If a significant fraction of total employment is accounted
for, scaling up is probably not necessary. Note that this type of compar-
ison is best done at the SIC 4 digit level rather than at the 2 digit level.
This is because not all employment in 2 digit SIC categories will be asso-
ciated with VOC emissions.
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Second, in order to develop locale-specific emissions-per-employee
factors, the agency will need to obtain the following information from each
point source: (1) SIC code, (2) employment within each SIC and (3) the type
of degreasing operation employed (cold cleaning, open top vapor cleaning or
conveyorized cleaning). The last delineation is required to exclude cold
cleaning from the derived factors. A potential drawback of this procedure
is that the quantity of data the agency must collect is increased and the
data may not be available for each source. If this is the case, emissions-
per-employee factors can be developed from a subset of the point source data
for which adequate data are available to do so.
Third, only photochemically reactive VOC should be scaled up. Infor-
mation on solvent type will also have to be elicited during the plant
contact, so that any resulting emissions-per-employee factors only represent
reactive VOC.
These preceding three points indicate that data requirements will be
substantially increased if scaling up is to account for open top vapor
degreasing and conveyorized degreasing emissions. The agency should be
aware of these requirements from the outset of the compilation effort.
Scaling up can not be accomplished if the proper data are not available.
4.3.2.2 Cold Cleaning Degreasing
The best alternative for estimating total areawide degreasing emissions
is to apply a per capita factor to cover small cold cleaning operations and
to handle larger vapor degreasers as point sources. A factor of 3 pounds
per capita per year is recommended for estimating small cold cleaning
emissions.*° A major advantage of this approach is that contacts to a great
many different and frequently small facilities are avoided, as in the pro-
cessing and storage of a great deal of data. A potential disadvantage of a
per capita approach is that the correlation between degreasing emissions and
population is not known. However, assuming a correlation exists is probably
reasonable in making estimates for broad urban areas.
The use of a per capita factor for estimating VOC emissions from small
cold cleaning operations should be qualified. First, the use of this
factor will include all cold cleaning emissions in the area of application.
Hence, to yield area source emissions, any cold cleaning solvent use iden-
tified in the point source inventory should be subtracted from the total.
To this end, cold cleaning degreasing should be distinguished from open top
and conveyorized degreasing in the point source inventory, as is discussed
previously in this section.
Second, the 3 Ib/capita/year factor represents only reactive VOC. A
factor of 4 Ib/capita-year would include all VOC of which approximately 25
percent is 1,1,1-trichloroethane; methylene chloride; and trichlorotri-
fluoroethane.2" The 4 Ib/capita/year factor could be used when an agency
needs to adjust inventories to exclude nonreactive compounds not on the list
in Chapter 2. Such a need would be encountered in only two circumstances:
(1) if the EPA reactivity policy were to change, or (2) a photochemical
4-17
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dispersion model is to be used which excludes additional compounds as mini-
mally reactive. However, the 3 Ib/capita/year will apply in most situations
and is recommended for use over a factor which includes nonreactive compounds.
More discussion of excluding nonreactive VOC is included in Chapters 2 and
6.
Third, the assumption is made that most of the solvent contained in the
waste evaporates ar' is not encapsulated or incinerated, and is not disposed
of outside the inventory area. If the agency is aware of different disposal
practices within its jurisdiction or is planning any control measures that
would alter these practices, this factor should be changed to reflect these
different practices. One estimate indicates that half of the emissions
occur during disposal of the waste solvent.20 Therefore, only this fraction
of the factor should be adjusted. For example, if 400 tons of solvent waste
is disposed of outside the inventory area, and 200 tons of solvent waste are
brought into the inventory area, then the net disposal outside the inventory
area is only 200 tons. If the 200 tons represent 25 percent of the waste
solvent, which means that 75 percent remains in the inventory area, then the
factor would be adjusted accordingly (1.5 + 1.5 x 0.75 = 2.6).
An alternative to inventorying cold cleaner emissions by per capita
factors is the use of cold cleaning emissions-per-employee factors. While
this method may be theoretically more accurate than using per capita factors,
because of the large number of SIC codes associated with cold cleaning
operations, many such emissions-per-employee factors would be needed to
scale up the inventory to encompass all cold cleaning emissions. Moreover,
emissions-per-employee factors that can be applied to cover only cold cleaning
operations have not yet been defined. Thus, while being theoretically more
accurate, the emissions-per-employee approach will require more effort and
documentation than will the per capita factor method.
4.3.3 SURFACE COATING
Surface coating operations can be separated into two groups, industrial
and nonindustrial. Industrial surface coating operations for such products
as appliances, automobiles, paper, fabric and cans are usually major sources
of volatile organic compounds, and should be listed as point sources although
small sources do exist. Nonindustrial surface coating includes refinishing
of automobiles and architectural coatings which are better inventoried as
area sources.
Section 4.3.3 discusses various techniques available for inventorying
surface coating area sources. Emphasis is placed on the nonindustrial
applications of surface coating, specifically automobile refinishing and
architectural surface coating. Be aware that other small industrial surface
coating operations may exist which emit less than the agency s point source
cutoff level. Small metal finishing shops are an example of this. Since
reliable techniques do not exist for handling small industrial surface
coating operations as area sources, the agency should try to identify as
many as possible in the point source inventory.
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4.3.3.1 Architectural Surface Coatings
Architectural surface coatings, often called "trade paints", are used
primarily by homeowners and painting contractors to coat the interior/
exterior of houses and buildings and of other structures such as pavements,
curbs or signs. Coating materials are applied to surfaces by spray, brush
or roller, and they dry at ambient conditions. Architectural coatings
differ from industrial coatings, which are applied to manufactured products
and are usually oven cured. Painting contractors and homeowners are the
major users of architectural coatings.15,22
Emissions result when the solvent which carries the coating material
evaporates and leaves the coating material on the applied surface. Solvents
used for thinning architectural surface coatings and for clean up after
application also contribute significantly to VOC emissions associated with
the architectural coating process. Waterborne coatings generally contain
much less solvent than do solventborne coatings. Additional information on
architectural surface coating can be found in References 15 and 22.
The most accurate method of inventorying VOC emissions from the apppli-
cation of architectural surface coatings is to obtain sales and distribution
data from local wholesale and retail suppliers of solventborne paints,
varnishes, and other coatings. Depending on the number of distributors,
direct contacts may be made to all or, alternately, brief survey forms may
be sent out if a large number of contacts must be made. Information should
be elictied during such contacts on the quantity of both solventborne and
waterborne coatings sold and on the average solvent content of each type of
coating. Moreover, information on the use of associated solvents for thin-
ning and cleaning must also be collected. By assuming typical densities of
6.5 and 8.6 pounds per gallon respectively, of solventborne and waterborne
coatings, and applying the average solvent contents determined in the survey
for each solvent type, emissions can be readily computed. Thinning solvent
emissions can be similarly calculated by assuming a density of 7.0 pounds
per gallon. One study suggests average solvent contents for solventborne
and waterborne coatings are 54 and 8 percent by volume, respectively.23
However, because the ranges of solvent contents in these two types of coat-
ings can vary so greatly, local data should be used if available. A basic
assumption in such calculations is that all the solvent in the coating
evaporates upon application.
An advantage of using local sales data to estimate architectural
surface coating emissions is that local consumption practices are taken into
account, which should enhance inventory accuracy. A disadvantage is that
much more work is required to develop emission estimates in this manner than
is required using the per capita factor, which is discussed in the subsequent
paragraph. Another disadvantage is that distributors may not be willing to
divulge sales information and may not know where their product is finally
used. In this last regard, sales data would necessarily have to be adjusted
to account for coatings distributed into and out of the inventory area.
If local data cannot be obtained on architectural surface coating, a
national average factor of 4.6 Ib/capita/year is recommended for estimating
architectural surface coating solvent evaporation. This factor is derived
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in Reference 18 from national consumption data. Thinning and cleanup solvent
use, which accounts for 25 to 40 percent of all solvent loss associated with
architectural surface coating, is included in this per capita factor.
None of the solvents used in architectural surface coatings or thinning
and cleanup contains any of the nonreactive compounds discussed in Chapters
2 and 6. A breakdown of architectural surface coating emissions by constit-
uent compounds is available in Reference 22.
4.3.3.2 Automobile Refinishing
Automobile refinishing is the repainting of worn or damaged automobiles,
light trucks and other vehicles. Surface coating during manufacture is not
considered refinishing. In automobile refinishing, lacquers and enamels are
usually spray applied in paint booths. Since vehicles contain heat sensitive
plastics and rubber, solventborne coatings are used which can dry in low
temperature ovens. Paint booths may be equipped with paint arresters or
water curtains to handle overspray. Additional process, emissions and
control information may be obtained from References 24 and 25.
One approach to inventorying auto body shops is to contact each one,
or a representative sample, and to obtain information on the quantity of
paint and solvent used in these operations. Such an approach is generally
not recommended except for larger facilities, because of the large number of
small shops in most areas and because of the unlikelihood that the shop
owners or managers would be able to provide the consumption or average
solvent information needed by an air pollution control agency.
An alternative approach is to use an emissions-per-employee factor and
to apply it to the number of employees in SICs 7531 and 7535. Based on
nationwide estimates of solvent loss from automobile refinishing and employ-
ment in these two SICs, and average factor of 2.6 ton/employee/year may be
applied as an estimate of auto body shop emissions in the area. Employ-
ment by SICs is available at county levels in Reference 21.
Another alternative is to use a per capita emission factor of 1.9
lb/capita/year.19 Because auto body refinishing may be generally expected
to relate to human activity, such a population based approach should serve
as a reasonable approach.
Solvents used in auto body refinishing will consist entirely of reactive
VOC. Thus, all solvent usage associated with auto body refinishing should
be included in the inventory used in an agency ozone control program.
4.3.3.3 Other Small Industrial Surface Coating
Industrial surface coating includes the coating, during manufacture, of
magnet wire, automobiles, cans, metal coils, paper, fabric, metal and wood
furniture, and miscellaneous products (see Table 2.2-1). Materials applied
in coating include adhesives, lacquers, varnishes, paints, and other solventborne
coating material. Many surface coating facilities generate sufficient
emissions to be considered major sources. However, small sources most
probably will still be present in any developed inventory area.
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To the maximum extent possible, small industrial surface coating oper-
ations should be treated as point sources. Only if the agency is aware of
numerous facilities emitting less than its point source cutoff level but
does not have the resources to contact these small facilities should the
point source totals be scaled up to account for the missing emissions.
Scaling up is discussed in Chapter 6.
Scaling up is usually based on employment totals within various indus-
trial sectors. The agency will need to develop emissions-per-employee
factors from data in its point source inventory on various surface coating
operations. The point source totals are scaled up by applying these factors
to estimates of total employment within appropriate SICs. Data on total
employment by industrial sector should be obtained from local planning
agencies. If local employment data are unavailable, Reference 21 presents
employment by SIC at the county level.
If scaling up is attempted to cover missing small industrial surface
coating, care should be taken because these operations are carried out in a
wide variety of applications covered by numerous SICs. Moreover, some small
operations may be found in facilities whose principal business is not typi-
cally associated with surface coating, such as manufacturing of tranformers,
computers or even crockpots. Particular attention should be paid to the
miscellaneous metal parts and products surface coating operations discussed
in Reference 27. A thorough effort is needed to locate all of the sectors
where surface coating is done, and to develop reliable factors for scaling
up the inventory totals. An example for scaling up emissions is presented
in Chapter 6,
4.3.4 GRAPHIC ARTS
The graphic arts or printing industry consists of approximately 40,000
facilities. About half of these establishements are in house printing
services in nonprinting industries. Printing of newspapers, books, magazines,
fabrics, wall coverings, and other materials is considered a graphic arts
application. Five types of printing are used in the industry: letterpress,
flexography, lithography, (roto) gravure, and screen process printing.
Detailed descriptions of the different types of printing operations are
given in References 16 and 28.
An emission factor of 0.8 Ib/capita/year is recommended for estimating
VOC emissions from small graphic arts facilities which emit less than 100
tons per year. Graphic arts facilities which emit more than 100 tons of VOC
per year are excluded from this factor and should be inventoried by point
source procedures in Chapter 3. Any emissions associated with less than 100
ton per year sources identified in the point source inventory should be
subtracted from the per capita derived emissions total.18 The following
example demonstrates the use of the factor.
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Example: An urban area with an inventory base year population of
808,500 people has been inventoried with a point source cut-
off of 25 tons per year per plant. Plant visits and stack
tests at a major publication plant equipped with rotogravure
presses has determined controlled emissions of 110 tons per
year at the facility. A questionnaire survey has identified
four additional plants with uncontrolled VOC emissions of 18,
22, 45, and 65 tons per year, respectively.
Calculations; Per capita derived emissions = 808,500 x 0.8 Ib/cap. yr.
= 649,000 Ib/yr. VOC
=320 tons/yr. VOC
Area source emissions = 320 tons
- (18 + 22 + 45 + 65) tons
= 320 - 150 = 170 tons/yr. VOC
Point source emissions = 150 + 110 = 260 tons/yr. VOC
Total graphic arts emissions = 260 + 170
=430 tons/yr. VOC
Note that the major point source is not subtracted from the per capita
derived emissions. Generally, major plants engaged in publication and
package printing are typically very large emitters and thus would be included
in the point source inventory.
The agency may elect to handle many of the smaller printing establish-
ments in its inventory as point sources. A questionnaire covering graphic
arts facilities is shown in Appendix D. However, because so many thousands
of small printing establishments exist in the U.S., and because each unit
emits, on average, less than ten tons per year of VOC, the agency may need
considerable resources to handle all of these establishments in the point
source data base. Moreover, care will have to be taken in (1) locating all
of these small operations, because so many are found in nonprinting indus-
tries and (2) accounting for additional solvents used for thinning and
cleanup. An emissions-per-employee approach is not recommended for the
graphics arts industry, because so many SIC codes other than 27 (printing
and publishing) would have to be covered in the scaling up process.
All of the solvents used in the graphic arts industry are considered
reactive and should be included in the VOC inventory developed for use in
the agency's ozone control strategy.
4.3.5 CUTBACK ASPHALT PAVING
Cutback asphalt is a type of liquified road surface that is prepared by
blending or "cutting back" asphalt cement with various kinds of petroleum
distillates. Cutback asphalt is used as pavement sealant, tack coat, and as
a bonding agent between layers of paving material. VOCs are emitted to the
atmosphere as the cutback asphalt cures and as the petroleum distillate,
used as the diluent, evaporates. The diluent content of cutbacks ranges
from 25 to 45 percent by volume, averaging 35 percent. Gasoline or naptha
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is used as the diluent in "rapid cure" cutback (RC) , kerosene is used in
"medium cure" cutback (MC), and low volatility fuel oil type solvents in
"slow-cure" road oils (SC).29
VOC emissions from cutback asphalts result from the evaporation of the
petroleum distillate solvent, or diluent, used to liquify the asphalt cement.
Emissions occur at both the job site and the mixing plant. At the job site,
VOCs are emitted from the equipment used to apply the asphaltic product and
from the road surface. At the mixing plant, VOCs are released during mixing
and stockpiling. The largest source of emissions, however, is the road
surface itself. Additional information on cutback asphalts is found in
Reference 29.
For any given amount of cutback asphalt, total emissions are assumed to
be equal, regardless of stockpiling, mixing and application times. The two
major variables affecting both the quantity of VOC emitted and the time
over which emissions occur are (1) the type and (2) the quantity of petroleum
distillate used as diluent. As an approximation, long term emissions from
cutback asphalts can be estimated by assuming that 95 percent of the diluent
evaporates from rapid cure cutback asphalts, 70 percent from medium cure
(MC) cutbacks, and about 25 percent from slow cure asphalts, by weight
percent. These percentages are applicable in estimating emissions occuring
during the ozone season. Some of the diluent appears to be retained perma-
nently in the road surface after application.10*29
Because the use of cutback asphalts varies so much from area to area,
local records should be accessed to determine usage in the area of concern.
Ideally, data should be obtained from the state or local highway department
or highway contractors on the quantity of each type of cutback applied, as
well as the diluent content of each. From these data, the equations or
tables in Section 4.5 of AP-42 can be used to compute long term solvent
evaporation. If the diluent content is not known by the local highway
department personnel, default values of 25, 35, and 45 percent can be
assumed for slow cure, medium cure, and rapid cure cutbacks, respectively.
All of the VOC from the petroleum-based diluents used in cutbacks is
considered photochemically reactive. Thus, all evaporative emissions associ-
ated with cutback asphalt use should be included in any VOC control strategy
inventory.
4.3.6 PESTICIDE APPLICATION
Pesticides broadly include any substances used to kill or retard the
growth of insects, rodents, fungi, weeds, or microorganisms. Pesticides
fall into three basic categories: synthetics, nonsynthetics (petroleum
products), and inorganics. Formulations are commonly made by combining
synthetic materials with various petroleum products. The synthetic pest
killing compounds in such formulations are labeled as "active" ingredients,
and the petroleum product solvents acting as vehicles for the active ingre-
dients are labeled "inert". Neither of these toxicological designations
should be interpreted as indicators of photochemical reactivity. Petroleum
products are often applied directly to control insects on trees (dormant and
summer oils), weeds (weed oils), and fungus on produce (light mineral oils).
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Inorganic pesticides are not of interest in the inventory, since they
contain no organic fraction.15'30
Pesticide use is typically associated with agricultural applications.
However, a significant enough quantity may be used in some urban and suburban
areas to warrant including pesticide emissions in the urban VOC inventory.
As examples of use, muncipalities may engage in various spraying programs to
control mosquitoes, tree damaging insects, or weed growth in shallow lakes
or tidal marshes. Pesticides are also used in homes and gardens.
If significant agricultural activity occurs within the area being
inventoried, local, state and Federal departments of agriculture should be
contacted to determine the quantities and types of pesticides applied. The
quantity of inorganics, which are mostly sulfur compounds, should first be
eliminated from the above total. Then, as a crude estimate, the remaining
synthetic and nonsynthetic total should be multiplied by a factor of 0.9 to
estimate that amount that evaporates and can be considered photochemically
reactive VOC.31 A much more detailed procedure which may be applied to
estimate emissions for agricultural applications is described in Reference
30. This procedure is much more data intensive and is recommended only in
areas where agricultural pesticides applications are a major source of VOC.
Several studies have shown that pesticide application in agricultural
areas may range from about 2 to 5 Ib/yr/harvested acre.13.30 This use
includes both synthetic and nonsynthetic pesticides. These factors should
be applied as a check on the figures determined from local sources.
Pesticide use for urban areas should be determined by contacting
appropriate state or local agencies, including local public health depart-
ments, parks departments, highway departments, or private concerns such as
utilities, exterminators, and landscapers. These groups will^know the
extent of pesticide application for insect control and weed killing, in
addition to that used in agricultural applications. The same types of data
should be obtained and the same procedures followed for estimating evapor-
ative VOC as are suggested for agricultural pesticides.
A nominal quantity of pesticides is additionally employed in homes and
gardens. This small amount is reported to be less than 0.25 lb/capita/year
on average and is covered in the next section as part of commercial/consumer
solvent use.1
All of the VOC accounted for by the above procedures is considered
photochemically reactive. If a seasonally adjusted inventory is compiled,
information on the seasonal application of each pesticide will have to be
collected. As might be expected, not all pesticides are applied during the
ozone season. For example, dormant season oils are applied during the cold
months of the year.
4.3.7 COMMERCIAL/CONSUMER SOLVENT USE
Certain commercial/consumer uses of products containing volatile organics
cannot easily be identified by questionnaires, surveys or other inventory
procedures yielding locale-specific emission estimates. Thus, a factor of
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6.3 lb/capita/year is recommended for estimating emissions from this category.
This factor includes the following commercial/consumer subcategories:
Reactive VOC
Household products 2.0 Ib/cap/year
Toiletries 1.4 Ib/cap/year
Aerosol products 0.8 lb./cap/year
Rubbing compounds 0.6 Ib/cap/year
Windshield washing 0.6 Ib/cap/year
Polishes and waxes 0.3 Ib/cap/year
Nonindustrial adhesives 0.3 Ib/cap/year
Space deodorant 0.2 Ib/cap/year
Moth control 0.1 Ib/cap/year
Laundry treatment < 0.1 Ib/cap/year
TOTAL 6.3 Ib/cap/yr
The above factors are based on national estimates of solvent use in
each of these end use sectors. Because of the difficulty involved in
developing local consumption estimates for the myriad products comprising
these categories, the local agency should generally not try to do so.18»19
It should not be inferred that the commercial/consumer factor is a
catchall estimate to account for deficiencies in point source or area source
inventories. Specifically, the factor does not include: small cold cleaning
degreasing operations; dry cleaning plants; auto refinishing shops; archi-
tectural surface coating applications; graphic arts plants; cutback asphalt
paving applications; and pesticide applications. These categories must be
inventoried by point or area source procedures and be tabulated separately.
The major organic materials comprising this 6.3 Ib/capita/yr factor are
special napthas, alcohols, carbonyls and various other organics. Nonreactive
halogenates used in aerosols and other products are excluded from this
factor. This value should be used in a VOC control program inventory.
Speciation data for use in other applications are available in Reference 18
and 19.
4.4 NONHIGHWAY MOBILE SOURCES
Nonhighway sources consist of mobile combustion sources such as rail-
roads, aircraft, ships and barges, off-road bikes, and farm equipment, as
well as lawn and garden equipment. In contrast, highway vehicles include
automobiles, buses, trucks and other vehicles traveling on established
highway networks. Emissions from nonhighway mobile sources are generally an
order of magnitude less than the combined highway vehicle VOC emissions.
Inventory methods of highway and nonhighway mobile source emissions are
distinctly different. Highway vehicles can be inventoried with traffic data
compiled by transportation agencies, as discussed separately in Chapter 5.
Inventory methods for nonhighway vehicles are presented in this section.
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4.4.1 AIRCRAFT
Emissions of volatile organic compounds from aircraft can be signifi-
cant in certain areas. Aircraft emissions are generally based on the
number of landing and takeoff (LTO) cycles performed. It is simpler and
more meaningful to collect LTO data from airports than fuel consumption
figures. Each landing or takeoff by an aircraft is an operation. An LTO is
comprised of one Ipiding and one takeoff by an aircraft, or operations
divided by two. Emissions from aircraft are commonly divided into three
categories: commercial, general, and military.
Several approaches can be followed for estimating LTOs in an area. The
preferred approach is to obtain information directly from each airport.
Very often airports will have detailed information on their operations that
can be helpful to the agency. A questionnaire, such as in Reference 32, can
be used for directly acquiring LTO and other useful information from airports
in the survey area. For commercial airports, questionnaire data can be
supplemented by published references. Airline schedules, such as given in
the Official Airlin^ Guide, report the type of aircraft for each flight.33
Airport Activity Statistics of Certified Route Air Carriers reports aircraft
departures performed in scheduled service by aircraft types. 3tf This latter
reference also gives a listing of aircraft types, which may be useful in
classifying commercial aircraft according to the categories listed above.
Aircraft emission factors in AP-42 are presented both in terms of the
quantity of organics emitted per LTO cycle (which includes all normal oper-
ation from the time the aircraft descends through 3,000 feet in altitude on
its approach and the time it subsequently reaches 3,000 feet in altitude
after takeoff) and in the quantity of organics emitted per hour in each mode
of LTO operation. Generally, the LTO averaged factors will be applicable in
most inventory situations. However, if detailed data are available on the
time spent by each aircraft in each LTO mode, such as taxi-idle and takeoff,
modal emission factors should be applied. Both kinds of factors are described
in Chapter 3 of AP-42.10,35
If LTO activity cannot be directly obtained from each airport, Federal
Aviation Administration publications may be used to determine LTO cycles
performed, as shown below:
1. FAA Air Traffic Activity36 - This publication gives the number of
operations performed by commercial, civil, and military aircraft at airports
with FAA regulated control towers. These airports will include all the
major nonmilitary airfields in the United States. Totals are given for
itinerant flights, such as those that terminate at an airport different from
the one at which they originated, and for local flights, including those
that terminate at the same airport. To determine total LTOs for each
aircraft category, itinerant and local operations should be summed.
2. Military Air Traffic Activity Report37 - This publication gives
the number of operations by military and civil aircraft performed at military
airfields. All operations are summed to determine LTOs.
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3. Census of U.S. Civil Aircraft38 - This publication can be used to
obtain rough estimates of the number of LTOs performed by civil aircraft at
airports without FAA regulated control towers, such as smaller public airports
and privately owned airstrips. The Census of U.S. Aircraft gives the number
of active civil aircraft in each county. These data can be used to estimate
LTOs by assuming that the total number of eligible aircraft in each county
is approximately equal to the number of daily LTO cycles performed by civil
aircraft. This method should be used to estimate LTOs only for airfields
not included in Reference 36.
Use of the above references will give the number of LTO cycles in
civil, commercial, and military classifications. By assuming the mix of
aircraft types included in each category, average emission factors can be
developed to compute the emissions for each category. This approach is
generally acceptable for civil aircraft. However, for detailed emission
inventories, it may be desirable to break down commercial and military LTOs
according to type of aircraft. By identifying LTOs by the classifications
given in AP-42, Compilation of Air Pollutant Emission Factors,10 emissions
may be computed to account for the aircraft mix in a certain area.
4.4.2 RAILROADS
This source category includes two types of activity: rail yard switch-
ing and road haul service. Railroad locomotives are generally not a major
source. However, significant amounts of VOC can be emitted from a concen-
tration of railroad activity in certain local areas, such as is associated
with large switch yards. Emission estimates are based either on the total
amount of fuel oil used by locomotives in an area or on total work output.
Both of the techniques described below estimate emissions by fuel use.
The preferred approach is to contact the railroad companies for infor-
mation on state or county railroad fuel use. Generally, only state totals
will be available from them, since their administrative units often cross
state lines. A less accurate alternative is to use Bureau of Mines data
from Mineral Industry Surveys39 to estimate use of locomotive fuel oil by
state.
State fuel use can be apportioned to each county on the basis of miles
of track per county, as determined from detailed state maps or obtained from
the rail lines. If state maps are employed, the track mileage should be
doubled in counties exhibiting significant rail yard operations. This is
because operations, and hence emissions, in rail yards are usually greater
than on main line track, a fact which is not determined from the use of
maps. An alternative and less accurate apportioning approach is to distri-
bute state fuel totals on the basis of county population as given in the
Census of Population. Lt° The population apportioning technique should be
used only when it is impossible to obtain track mileage data. This tech-
nique assumes that most yard operations take place in large cities.
Residual oil, which may be used by railroads in addition to diesel fuel
oil, can be accounted for if Bureau of Mines figures are used by adding the
state residual oil total for railroads to the distillate oil total before
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apportioning to counties. The use of coal by railroads is negligible and
does not need to be considered.
Once fuel oil consumption by locomotives is determined for the survey
areas, the appropriate emission factors from Chapter 3 of AP-42 should be
used to estimate organic emissions. Generally, the average factors in AP-42
should be used unless specific information is available on each engine type
in an inventory. An example questionnaire for collecting railroad activity
can be found in Reference 32.
4.4.3 VESSELS
This source category includes ocean going ships, river vessels, and
small pleasure craft used on lakes and rivers. Emissions are determined for
vessel travel (and dockside operations) by estimating the quantity of fuel
used for each kind of vessel in the survey area. These vessels are generally
a minor source of VOC emissions, but they may be included in a detailed
inventory in areas where such traffic is heavy or where docking activity is
considerable. A detailed discussion of vessel types and the methods used to
obtain fuel consumption data is presented below.
1. Coal powered vessels: A few vessels, notably in the Great Lakes
region, still burn anthracite coal. No easy methods are available for
estimating local emissions for these vessels, because only nationwide fuel
totals are available.41 Thus, information on local fuel consumption can be
obtained only from estimates made by port authorities or ship operators.
2. Gasoline powered vessels: This category includes small pleasure
craft operated on lakes, rivers, and coastal areas. Most of these craft are
powered by outboard motors, but inboards and inboard outdrives using gasoline
are also included. Gasoline use for states may be estimated as followed:
Inboard gasoline = # registered lnboards x 3 gal/hr x 10 (C) hr/yr
consumption (gal/yr)
Outboard gasoline = # registered Outboards x 1.5 gal/hr x 10 (C) hr/yr
consumption (gal/yr)
The factor C is a climatic factor which accounts for a longer pleasure
boating season in warmer areas. C is the number of months during which the
monthly mean temperature exceeds 45°F for counties north of 43° latitude,
48°F for counties between 37° and 43° latitude, and 55°F for counties south
of 37° latitude. State boat registrations are obtained from a boating
industry publication,42 but they should also be available from the state
agency responsible for boat registrations. Vessels powered by inboard/
outdrives are included with inboards to estimate fuel use. The fuel use
factors are derived from Reference 43.
After state fuel use totals are obtained they can be apportioned to
counties by county inland water surface area modified to include a surface
area for any costal regions.411 The standard method in apportioning to
counties could be improved by local data. Knowledge of where boating
activity actually takes place will provide more accurate county totals than
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will apportioning to counties only on the basis of water area. One method
is to obtain gasoline sales data at marinas. This should be done for esti-
mating emissions from dispensing outlets, and it could be directly applied
to gasoline powered vessel emission estimates. Boat registrations by
county, if available, may be useful, but boats are not necessarily used in
the county in which they are registered in all states. Reference 44 is also
deficient in that any man made reservoirs constructed since 1960 are not
included. The method for accounting for vessel use in coastal areas is very
poor and could be improved tremendously by local gasoline sales data.
3. Fuel oil (including diesel) powered vessels: Fuel consumption
totals for these vessels, which represent the major subcategory of interest,
include the fuel used by large cargo and passenger ships, oil tankers,
tugboats, and all other steamships and motorships that use fuel oil.
Fuel consumption totals can be obtained by:
Questionnaire surveys of shipping and tugboat companies and con-
tact with the local port authorities. This method provides the most
accurate local data for fuel consumption rates of many of the vessels
in the area. Such a survey is not often comprehensive enough to include
all vessels, however, because many vessels move in and out of the port
area during the year and would be difficult to contact.
Vessel movement data available from the U.S. Corps of Engineers,45
together with fuel consumption factors and Bureau of Mines fuel consump-
tion figures.39 This method is much easier to implement than a question-
naire survey, and may be almost as accurate despite the generalizations
that must be made to effect its use. This method is described in
detail later.
Use of Bureau of Mines figures only. State totals for fuel oil
sold to vessels are given in Reference 39. Not all the fuel sold for
vessel use is by any means consumed within the state boundaries, how-
ever, much of the fuel may be consumed far out at sea and not in a port
or waterway area. If it is assumed that 75 percent of the distillate
oil figure given in Reference 39 and 25 percent residual oil total are
consumed in ports and waterways within the state, a rough estimate of
vessel fuel oil consumption can be obtained. This method should not be
used in conjunction with a detailed emission inventory, however, and is
useful mainly to obtain an order-of-magnitude emission estimate from
vessel operations.
If fuel consumption totals are determined from a questionnaire survey,
the fuel oil consumption figures should be simply assigned to the counties
where the vessel are operated. If vessel movement data obtained from
Reference 45 must be used, extensive apportioning measures are necessary.
The apportioning method becomes somewhat involved, because both underway and
dockside emissions should be considered. Underway and dockside emissions
include the emissions that occur when a vessel is moving under its own power
through a waterway and when it is maneuvering into its dock space. Average
fuel consumption rates during these periods for steamships and motorships
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are 44 and 19 gallons per nautical mile, respectively.46 In-port, or dock-
side, emissions occur when a ship operates its engines or boilers in port to
provide power for ship utilities. Average fuel consumption rates are 1900
gallons per day of residual oil for steamships and 660 gallons per day for
motorships.1*5 The local port authority should be able to supply a figure
for the average number of days a ship remains in port. If not, a figure of
3 days per vessel is typical.
Fuel consumption can be estimated from vessel movement data for fuel
oil powered vessels as follows:
Step 1. Determine in-port fuel consumption.
The number of vessels entering a port can be found in Section 2 of
parts 1, 2, 3 and 4 of Waterborne Commerce of the United States.
Section 2 lists vessel traffic on waterways for self propelled vessels
and other according to type and draft of vessel and direction of trip.
For the first step in the determination of in-port emissions, select
the entries for ports in Section 2, and assume that only self propelled
vessels with a draft greater than 18 feet will be operating under their
own power when in port. Determine the number of vessels meeting these
conditions that enter each port, and multiply by 3 days per vessel, or
by a number recommended by the port authority, to calculate the number
of vessel-days in each port. Vessel-days in port must be distributed
between those ships that use residual oil and those that use distillate
(diesel) oil. This procedure is illustrated as follows:
A. From Reference 39 determine the amounts of distillate and
residual fuel oils sold for use by vessels in each state. Example fuel
and sales for a particular state are given below:
Distillate oil consumption = 232 x 103 bbl = 9,750 x 103 gal
Residual oil consumption = 1,000 x 103 bbl = 42,000 x 103 gal
Convert fuel consumption figures to vessel-days:
-, j 9,750 x 103 gal _ , , Rnn v^ooei-davs
Distillate vessel-days = 660 gal/day ~ U'8° Y
•, j 42.000 x 103 gal _ _„ ,00 vessei_clavs
Residual vessel-days = 1>900 gal/day 22>1 Y
B. Then total vessel-days = 14,800 + 22,100 vessel-days
14 > 800 inn0/ — /. r\°/
Percent distillate vessel-day = 36 900 x 10U/» - w/,
C Then at each port in this state, assign 40 percent of the
total vessel-days to motorships (diesel fuel users) and 60 percent to
steamships (residual fuel users).
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Finally, in-port fuel consumption can be calculated by multiplying the
total distillate oil vessel-days by 660 gallons per day, and the total
residual oil vessel-days by 1900 gallons per day.
Step 2: Determine fuel consumption for vessels underway:
Underway emissions will be calculated for diesel fuel use only.
In a typical harbor there are tugboats and small craft (draft less than
18 feet) that use diesel fuel. Because most of these do not operate
their boilers or engines when in port, most of their emissions occur
when the ships are underway. Vessels using residual oil also have
underway emissions, which are approximately accounted for when emissions
for vessels using diesel fuel are calculated by the technique described
below.
Calculation of underway fuel consumption:
A. Subtract the sum for all ports of the in-port diesel fuel
consumption from the state total for distillate oil consumption by
vessel as given by Reference 39.
B. Distribute the remaining fuel consumption figures to ports and
waterways by tonnage handled, as given in Section 1 of Waterborne Commerce
of the United States. Underway fuel consumption totals are assigned to
counties using the description of waterways given in Waterborne Commerce of
the United States. In cases where a waterway borders more than one polictical
jurisdiction, divide the fuel use equally between jurisdictions. In instances
where a waterway, such as a river, passes by a series of counties, assign
the emissions to counties according to shoreline mileage along the waterway.
Note that two methods have been given that can be used for a detailed
survey of fuel oil use by vessels. As mentioned previously, Bureau of Mines
data alone are useful only for a rough guess of vessel fuel oil use. Little
can usually be gained by using both of the methods for fuel oil consumption
by vessels. Vessel movement data serve as replacements for questionnaires,
and vice versa. A modified version of this method would be to contact port
authorities for vessel movement data. The Waterborne Commerce of the United
States data are much more nearly complete, however, and should be used if at
all possible. All four parts of Waterborne Commerce of the United States
are not necessary for completion of a vessel fuel use inventory. Only that
part that covers the geographic area being considered need be used. The
choice of either of the first two methods depends on whether sufficiently
thorough (or adequate) data could be obtained by a questionnaire survey to
justify the time required to institute the survey. If detailed data for
individual types of vessels such as tugboats, tankers and cargo ships are
desired, questionnaires should be used. If only a reliable estimate of the
total fuel consumption by vessels is desired, vessel movement data are
adequate.
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Once fuel consumption data are available, emissions can be calculated
for each class of vessel by using appropriate emission factors in Chapter 3
of AP-42. If extremely detailed data are available for fuel consumption as
a function of operating mode, the more detailed procedures and emission
factors prescribed in AP-42 can be employed.
4.4.4 OTHER OFF-HIGHWAY FUEL USE
Off-highway internal combustion engines are both gasoline and diesel
fuel powered. The first category includes farm tractors, lawnmowers,
motorcycles and snowmobiles. The latter category includes farm tractors,
construction equipment, emergency generator power units and compressor
engines. While each of these source categories may be relatively small in
many areas, their collective emission rates can be significant.
Because snowmobile activity does not correspond to the ozone season,
the agency may consider ignoring this minor category in its inventory
effort. Some of the other categories, however, such as tractors, lawnmowers
and construction equipment, may be relatively more active during the ozone
season. For many of these source categories, emissions are calculated from
on the amount of fuel used by each type of equipment.
The following procedures allow emission estimates to be made for these
sources, based on information found in publications and on national average
conversion factors. Locale-specific techniques are not available for
estimating emissions from these sources. However, to the extent that local
fuel use data, or even locally derived conversion factors, are available for
use in the following equations, they should be used in the emission calcu-
lations presented below.
4.4.4.1 Off-highway Motorcycles
Gasoline use is estimated by assuming that, on average, motorcycles
achieve 42.5 miles per gallon and travel about 700 off highway miles per
year. By using these conversion factors, state motorcycle registrations
available from Reference 8 can be apportioned to the county level on the
basis of population, as follows:
County = State County _ 700 miles/yr
Consumption Registrations x Population (gal/yr) x 42 5 miles/gallon
State ' S
Population
County fuel consumption is then multiplied by the appropriate emission
factors in AP-42 to estimate local emissions. In the above equation, if
local mileage, fuel efficiency or county registration data are known, they
should be used to estimate county consumption.
4.4.4.2 Farm Equipment
Farm tractors account for the bulk of activity in this category, with
lesser amounts of fuel being used by combines, balers, harvesters, and
general utility engines for irrigation and miscellaneous purposes. Both
gasoline and diesel fuel can be consumed by farm machinery.
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TABLE 4.4-1. USE RATES, CONSUMPTION RATES AND POPULATION DISTRIBUTION
FOR HEAVY DUTY AGRICULTURAL ENGINES43
Device Annual
Uses
(hr/yr)
Combines
Balers
Harvesters
General Purpose
Tractors
71
24
120
50
*
Fuel consumption rate
(gal/yr)
Gasoline Diesel
2.34
2.34
2.34
3.51
2.28
1.5
1.5
1.5
1.94
2.98
Population density
(%)
Gasoline Diesel
57
100
0
50
65
43
0
100
50
30**
490 hr/yr Diesel, 291 hr/yr Gasoline
&&
About 5% is LPG, which is not included here.
State consumption of gasoline and diesel fuel for each category is
determined as follows:
State consumption (gal/yr) =
Equipment population x Use (hr/yr) x Fuel rate (gal/hr)
Equipment populations and use factors can be obtained either from the
Census of Agriculature1*6 or derived from data shown in Table 4.4-1. County
consumption of each fuel is determined by apportioning the state total for
all farm equipment to counties according to number of farm tractors in each
county.
4.4.4.3 Construction Equipment
County gasoline and diesel fuel use is determined as follows:
State employment for SIC 16 x County population
CC - National tuel use x National employment for SIC 16 x State population
Where: CC = County consumption
National average use of gasoline and diesel fuel is shown in
Table 4.4-2 below.
TABLE 4.4-2. NATIONAL FUEL ESTIMATES FOR 1973, GALLONS
43,48
Equipment type
Construction
Industrial
Lawn and garden
Snowthrowers
Snowmobiles
Gasoline
243 x
612 x
827 x
25 x
80 x
106
106
106
106
10 6
Diesel
4,453 x
1,094 x
105
106
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Employment data are available from Reference 21 and population data
from Reference 40. If local fuel use is known, it should be used to enchance
the accuracy of the resulting emission estimate.
4.4.4.4 Industrial Equipment
County gasoline and diesel fuel use by industrial equipment (forklifts,
generators, pumps, miscellaneous machinery) computed as follows:
County employment for SICs 10-14,20-39,50,51
CC = National fuel use x National Empioyment for SICs 10-41,20-39,50,51
Where: CC = County consumption
National fuel use data are available in Reference 43. Employment data
are available in Reference 21. Local fuel consumption data or apportioning
factors should be used when known for the area.
4.4.4.5 Lawn and Garden Equipment
Gasoline use by lawn and garden tractors, mowers, tillers, and snow-
throwers, is calculated for each county based on national fuel use data in
Reference 43. National fuel use is apportioned to counties on the basis of
number of single unit dwellings,49 number of days per year with minimum
temperature greater than 32°F, and county snowfall.50 Number of single unit
housing structures is the primary apportioning factor, and the other items
adjust for the extent of summer vs. winter related uses. The appropriate
equation for apportionment of fuel use is :
Where: CC = County consumption
NLGC = National lawn and garden consumption (the national
gasoline consumption of lawn and garden equipment
other than snowthrowers)
CUS = County unit structures
NUS = National unit structures (46,780,067 single unit
structures)48
DMTN = Days min. temp > 32°, nation (the sum of the total
days for all counties in the nation: 788,335 days/year
summed over all counties)
DMTC = Days min. temp > 32°, county
C = 0 for counties with less than 30 inches annual
snowfall
C = 1 for counties with more than 30 inches annual
snowfall
NSC = National snowthrower fuel consumption
CP = County population
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CS = County snowfall
SZP = Snow zone population (population of all counties with
more than 30 inches annual snowfall: 116,049,900
people)1*®
SZS = Snow zone snowfall (sum of snowfalls in all counties
with more than 30 inches annual snowfall: 101,437.74
inches)48
An agency may wish to ignore gasoline consumption by snowblowers in an
inventory, since these emissions occur in the winter months. Consult Chapter
6 for information of seasonal adjustment of VOC emissions.
4.5 SOLID WASTE INCINERATION:
Solid waste may consist of any discarded solid materials from industrial,
commercial or residential sources. The materials may be combustible or
noncombustible and are often burned to reduce bulk, unless direct burial is
either available or practical.
In some local areas, solid waste disposal by burning can be a signif-
icant source of organic emissions. The area source solid waste VOC emis-
sions category includes on site refuse disposal by residential, industrial,
and commercial/institutional sources. On site incineration is the unconfined
burning of waste leaves, landscape refuse or other refuse or rubbish. Slash
and large scale agricultural open burning are not included in this VOC emis-
sion category. Large open burning dumps and municipal incinerators are
usually classed as point sources, but many smaller incinerators may be so
classified, depending on the needs of the agency. For emission inventory
purposes, only solid waste actually burned is of interest. Unfortunately,
very little quantitative information about on site solid waste disposal is
available.
Some locales have conducted comprehensive surveys of solid waste dis-
posal practices. Where such a survey is available, it should be used to
estimate solid waste quantities. Many such surveys cover only collected
waste, however, and are of limited value for determining on site waste
disposal quantities.
If solid waste survey data are not available, quantities are usually
estimated by per capita generation factors. Nationwide, it is estimated
that about 10 pounds of solid waste are generated per capita per day.51 By
proportioning the various disposal methods, waste generation can be esti-
mated for on site incineration and open burning. In addition, data useful
for estimating area source solid waste quantities are available in several
surveys of nationwide solid waste disposal practices.52"54 It should be
noted that data on nationwide or regional solid waste generation may yield
extremely inaccurate predicitions for local areas. The tremendous variation
in solid waste disposal practices from one community to another renders such
nationwide averages rough estimates at best. Furthermore, local regulations
governing solid waste disposal should be taken into account. In some areas
and under certain conditions, on site incineration is regulated or may be
prohibited. If so, the corresponding generation factors(s) should not be
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applied. Under such circumstances, assume that the solid waste normally
allotted to on site disposal is handled by some method not involving burning,
such as landfilling or resource recovery.
4.5.1 ON SITE INCINERATION
The waste generation factors given in Table 4.5-1 may be used with
appropriate emission factors in AP-42 to estimate on site solid waste incin-
eration by residential, commercial/institutional, and industrial sources.
Care should be taken in the application of these waste generation factors.
If a number of on site incinerators have been identified as point sources,
it may be appropriate to reduce or eliminate the area source estimates. In
addition, these factors are 1975 data and should be updated to the inventory
base year with procedures which can be obtained from NEDS contacts in EPA
Regional offices. If data are available from registration or permit files
for solid waste disposal equipment, these data may provide a more accurate
estimation of on site incineration quantities then the factors given here.
Reference 54 presents additional data on incinerators, such as size of units
or controls, that may be useful in making more detailed estimates for on
site incineration.
TABLE 4.5-1. FACTORS TO ESTIMATE TONS OF SOLID WASTE
BURNED IN ON SITE INCINERATION3
Residential Commercial/Institutional Industrial
EPA (Tons/1000 (Tons/1000 population/ (Tons/1000 mfg
Region population/yr) yr) employees/yr
I
II
III
IV
V
VI
VII
VIII
IX
X
National
average
52
11
4
4
61
23
75
87
90
90
41
64
65
54
23
87
33
37
49
5
29
50
125
180
560
395
420
345
325
430
80
170
335
References 21, 40, 52, 53.
4.5.2 OPEN BURNING
Little national data are available to estimate open burning activities.
However, since many areas require open burning permits, open burning can be
best estimated by contacting the most knowledgable local official and by
taking into account the effects of any local open burning restrictions or
prohibition. If no local estimates can be made, the waste generation factors
4-36
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in Table 4.5-2 may be used to estimate the quantity of solid waste to multiply
by the appropriate emission factor from AP-42. Note that the factors for
residential and commercial/institutional open burning are applied to rural
populations. Also, these factors should be updated to inventory base year
levels using procedures available from NEDS contacts in EPA Regional offices.
TABLE 4.5-2. FACTORS TO ESTIMATE TONS OF SOLID WASTE DISPOSAL
THROUGH OPEN BURNING3
Residential Commercial/Institutional Industrial
(Tons/1000 (Tons/1000 population/ (Tons/1000 mfg
population/yr) yr) employ ees/yr
National
average
450b
24b
160
fReferences 21, 40, 52, 53, 55.
For rural population only. Open burning assumed banned in urban areas.
4.6 SMALL STATIONARY SOURCE FOSSIL FUEL USE
This source category includes small boilers, furnaces, heaters, and
other heating units too small to be considered point sources. Note that
both point and area source combustion equipment produce only small amounts
of organics relative to most other sources. Thus, the agency may not con-
sider it worthwhile to perform the detailed procedures given below, if its
primary concern is updating the VOC inventory and if an existing inventory
already includes combustion. The procedures below may be followed if a
detailed VOC inventory is needed or if other pollutants from small station-
ary source fuel combustion are of concern. Because VOC emissions from this
source are estimated by simply multiplying the typical quantity of fuel used
and an appropriate emission factor, the techniques below are designed to
yield fuel use data for various types of combustion equipment.
Area source stationary source fuel use may be divided into three
categories: residential, commercial/institutional, and industrial. Resi-
dential dwellings are all structures containing fewer than twenty living
units, so that large apartment houses are excluded. Commercial/institu-
tional facilities are establishments engaging in retail and wholesale trade,
schools, hospitals, government buildings, and apartment complexes with more
than twenty units per structure. The commercial/institutional category
covers all establishments defined by SIC groups 50-99. Industrial fuel
combustion includes all manufacturing establishments not classified as point
sources. These establishments are defined by SIC groups 19-30.56 Collec-
tively, the three categories account for all the stationary fuel combustion
activities not usually reported as point sources.
The area source fuel use total is determined by subtracting all fuel
used by point sources from the area-wide total of fuel use. Hence, before a
specific methodology can be applied to calculate area source fuel use, the
4-37
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total fuel consumed in an area must be determined. Such data are usually
obtained from fuel dealers and distributors, published references, or govern-
ment regulatory agencies. Some fuel retailers maintain sales records that
can be a valuable source of information for determining total fuel consump-
tion. The information needed from fuel dealers concerns their annual sales
to each source category (preferably by county). The area source totals of
residential and cc .jnercial/institutional fuel consumption are then simply
the fuel dealers' figures minus any fuel consumed by the fuel dealers. The
accuracy of survey results will be significantly reduced if some fuel dealers
are overlooked. It may be that not all fuel dealers will be able to furnish
adequate information. Generally, natural gas dealers can best furnish the
required data. Other dealers either are reluctant to release information,
or they simply do not have the detailed breakdowns required.
Unfortunately, the above techniques cannot assure that fuel dealer
sales accurately represent fuel consumption. Sales of coal to industrial
sources or of wood to residential sources, for instance, may represent only
a part of the total fuel consumed, as much of the fuel consumed in some
areas may not come from retail dealers. Other methods should be used for
those cases in which fuel dealers cannot provide adequate data on total fuel
sales. It should be emphasized, however, that information provided by
dealers, although perhaps incomplete, can provide insights into fuel use
patterns that would not be discovered by other methods. An example ques-
tionnaire for obtaining fuel use data from fuel suppliers is included in
Reference 32.
Published references are the most common sources of fuel use data.
Reports produced by the U.S. Bureau of Mines contain data on fuel sales and
distribution. The advantages of using this information are that data for
all parts of the nation are readily available and are updated every year.
The drawback to the use of this material is that fuel data are reported by
state only. They are not broken down into the desired source categories,
and county totals must be estimated by apportioning state totals. This geo-
graphical apportioning step, which may also be necessary for data obtained
from fuel dealers, can become quite complicated and can involve a large
number of calculations.
Finally, useful data may sometimes be obtained from federal and state
regulatory agencies. The Federal Power Commission compiles data on fuel
used by electric utilities and on natural gas company sales and pipeline
distribution.57,58 State utility commissions may be able to provide similar
data. In addition, state revenue or tax departments may have data that
would be helpful for determining fuel usage.
4.6.1 FUEL OIL CONSUMPTION
Data collection for fuel oil consumption covers the use of both distil-
late and residual oil. Distillate oil includes fuel oil grades 1, 2 and 4.
Diesel fuel and kerosene also can be considered distillate oils. Nation-
wide, residential and commercial/institutional sources are the largest
consumers of distillate oil. Residual oil includes fuel oil grades 5 and 6.
In most areas, residual oil is not used by residential sources, but sign-
ificant amounts may be consumed by industrial and commercial/institutional
users.
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Literature data must be generally relied upon to determine total fuel
oil consumption. Local fuel dealers and government agencies usually have
been unable to supply adequate data on fuel oil use. The data published by
the Bureau of Mines in Sales of Fuel Oil and Kerosene are the most
acceptable.39 For selected years, data are also available from the Census
of Manufacturers, published by the Bureau of the Census.59 This publication
is not produced annually, however, so it is of limited use for most area
source inventory purposes.
A procedure for determining area source fuel consumption can be found
in Census of Manufacturers and other publications.50 This procedure involves
calculating state fuel oil consumption, substracting point source consump-
tion data, and allocating fuel oil use into county inventory area. A full
discussion of this method is found in the AEROS Manual Series, Volume II.2
Due to the complexity of the method, it may be very cumbersome to apply
on a large scale. Persons who wish to obtain the computer output for selected
counties or further information may contact their EPA Regional office or the
National Air Data Branch, U.S. Environmental Protection Agency, Mail Drop
14, Research Triangle Park, NC 27711.
A simplified version of the method (discussed in AEROS) can be employed,
but it sacrifices the accuracy of the results. Variations of the method may
include using different correlative relationships to predict fuel oil use.
For instance, to predict distillate oil used for space heating, equations of
the following types may be use:
Oil
consumed = # of oil burners x avg size (BTU/hr) x 8760 (hr/yr) x load
140,000 BTU/gallon
or,
Oil consumed =
# of oil burners x heat loss (BTU/hr) x heating degree days x use factor
140,000 BTU/gallon x Design Range (°F)
where the heat loss is dependent on the average square feet of building
space. The design range is the difference between inside temperature and
the design outside temperature for an area.60
Use of these relationships requires collection of substantially more
source data and determination of local load and use factors. Fuel oil trade
association publications,61 oil dealers, and utility companies may be able
to provide some of this information. Modifications of the above equations
may provide relationships for predicting residential, commercial/institu-
tional, or industrial space heating fuel oil use, which can be summed to
obtain grid, county or state totals. The derived totals should be adjusted
to conform with the state totals given in literature.39 This step corrects
for variations in the parameters used in the above equations.
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4.6.2 COAL CONSUMPTION
A determination of both anthracite and bituminous coal consumption may
be necessary. Anthracite, or hard coal, is found almost exclusively in
Pennsylvania and is used in significant quantities only in states within
easy shipping distance from Pennsylvania. Anthracite may be consumed by all
source categories, although most is used by residential sources. Mining of
bituminous, or soft coal, is more widespread than anthracite, so that bitu-
minous coal is available in most areas of the country. Also considered as
bituminous coal are lower grades of subbituminous coal and lignite. Bitu-
minous coal is often favored for use by electric utilities, industries and
coke producers. Bituminous coal is used in some areas for residential and
commercial/institutional heating.
The same general techniques used for fuel oil may be adapted to deter-
mine coal consumption. Residential coal use is calculated for each county
with on the following equation:
nn^0-,, [7.6414 - (1000/degree days)]
Tons of coal per dwelling unit = 0.003874 e
The number of dwelling units using coal for space heating is obtained from
Reference 56 and is updated annually with additional data from Bureau of
Mines or Bureau of the Census data. Degree days are obtained from Reference
50. The coal use predicted by the above equation is distributed between
anthracite and bituminous coal based on the estimated residential market
share of each.48 Use of coal for other than space heating purposes is
ignored. Methods used for calculation of commercial/institutional and
industrial coal use are basically the same as those used for fuel oil.
State totals are obtained from References 62 and 63.
4.6.3 NATURAL GAS AND LIQUIFIED PETROLEUM GAS CONSUMPTION
Few problems should be encountered in determining natural gas use by
county. Natural gas companies are usually excellent sources of data. If
gas companies are unable to supply adequate data, information from the
Federal Power Commission,58 state utilities commissions, and literature may
be used. Liquified petroleum gas (LPG) use may also be considered in area
source inventories. The LPG contribution to total emissions is not sign-
ificant in most areas. Wherever LPG use is considerable, however, it may be
reported as "equivalent natural gas" by assuming for emissions that each
gallon of LPG is equivalent to 100 cubic feet of natural gas.
Residential natural gas use by county is computed using the following
equation:
Therms of Natural Gas Consumed =
0.367 ,C. 0.588 0.125
47.5 x A x B x (-) x E
Where: A = total number of natural gas customers
B = annual heating degree days
C = number of dwelling units using natural gas for space heating
4-40
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D = the larger of the number of dwelling units using natural gas
for cooking or hot water heating
E = median number of rooms per dwelling unit.
Item A is obtained from American Gas Association reports, B from
Local Climatological Data,50 and C, D and E from the Census of
Housing.133 For annual updates of each parameter, contact the NEDS
representative in any EPA Regional office.
The resulting natural gas use in therms (one therm = 100,000 BTU)
is converted to cubic feet on the basis of natural gas heating value
(usually 1000 to 1050 BTU/cubic feet). Residential LPG use is computed
by county, using a simpler equation based only on number of dwelling
units, heating degree days, and a regional use factor for LPG consumed
in cooking and water heating.
Therms of LPG consumed = (376 +0.209 B) x H + (IxJ) + (KxL)
Where: B = annual heating degree days
H = number of occupied dwelling units using LPG for space
heating
I = regional average consumption for water heaters, therms
J = number of occupied dwelling units using LPG for water
heating
K = regional average consumption for cook stoves, therms
L = number of occupied dwelling units using LPG for cooking
Regional average therms consumed by water heaters and cooking have been
estimated by the American Gas Association and are summarized in Reference
48.
Commercial/institutional and industrial use of natural gas and LPG may
be estimated by using the same methodology presented for fuel oil use and by
obtaining state totals for fuel use from References 64 and 66. However,
since natural gas utility companies usually have excellent records of sales
data preferably are obtained directly from the gas company. If records are
not detailed enough to give county totals, some apportioning may be necessary.
If this is the case, the particular institutions and school systems that
comprise the commercial/institutional subcategories identified in Section
4.6.1 should be contacted directly. If fuel use totals for these categories
can be obtained directly, use of the equations and procedures for commercial/
institutional subcategories can be avoided. This step is particularly
desirable for a detailed source inventory, since the equations in this
section and in Section 4.4.1 do not always yield accurate predictions of
fuel use in a small area.
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4.6.4 OTHER FUELS
Other fuels which may appear as area source fuels are wood, coke and
process gas. Census of Housing1*9 data may be used to estimate residential
consumption of wood, according to the following equation: >
ARPH
Residential wood use (tons/yr) = 0.0017 x NHUHW x HDG x -^
Where: NHUHW = Number of housing units heating with wood
HDG = Heating degree days
ARPH = Average rooms per housing unit
Commercial/institutional and industrial wood use is usually ignored,
unless surveys of potential sources indicate that wood is consumed by small
sources in significant quantities. The most common users of wood as fuel
are those wood processing plants that burn wood waste.
Users of coke and process gas can usually be identified only through
questionnaire surveys. Neither of these fuels will be used by establish-
ments which are classed as area sources. Process gas use is most common in
petroleum refineries, certain chemical processing industries, and iron and
steel mills. Coke is consumed mainly by iron and steel mills and foundries.
4.7 OTHER AREA SOURCES
Area sources yet to be discussed are forest fires, slash burning, agri-
cultural burning, structure fires, frost control burners, and natural organic
sources. Although they are often intermittent in nature, many of these
sources can produce large quantities of air pollutant emissions. Some of
these sources, such as orchard heaters and certain kinds of agricultural
burning, are not active during the oxidant season. These area sources are
discussed briefly in this section, along with techniques for making crude
emission estimates.
4.7.1 FOREST FIRES
Organic emissions from forest fires in certain rural areas can be very
large at least in the short term. Estimates of the quantity and types of
growth burned in a given area should be available from the U.S. Forest
Services state forestry or agriculture departments, or local fire protection
aeencies If local estimates are not available, the U.S. Forest Service
annually publishes Wildfire Statistics, which gives the total acreage burned
for each state.67 However, this document does not provide burned acreage by
county, so local fire and forestry officials should be consulted for estimates.
If sufficient information cannot be obtained from local officials, the state
total from Wildfire Statistics should be apportioned to counties according
to forest acreage per county." If this information is not available from the
appropriate state or local agency, the total acreage burned can be divided
equally among counties with significant forest acreage, as shown on state
maps.
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The determination of tons of growth burned per acre ("fuel loading") is
equally important. Local officials should be contacted for this information.
The emissions in the study area are then obtained by multiplying the appro-
priate emission factor in AP-42 by the fuel loading, then multiplying this
product, by the amount of forest acreage burned.
Average fuel loadings, emission factors, and estimates of organic
emissions from forest fires in the various U.S. Forest Service Regions are
presented in Section 11.1 in AP-42.
4.7.2 SLASH BURNING AND AGRICULTURAL FIELD BURNING
Waste from logging operations is often burned under controlled condi-
tions, to reduce the potential fire hazard in forests and to remove brush
that can serve as a host for destructive insects. Officials of the U.S.
Forest Service or state forestry department should be contacted for estimates
of the area burned and quantity of slash per acre. If an estimate of the
quantity of slash burned per acre cannot be obtained from other sources, a
figure of 75 tons per acre can be used.
Also included in this source category are agricultural fieldburning
operations such as stubble burning and burning of land clearing refuse.
Little published information is available on this subject, so burning
activity estimates must be determined through state agriculture departments
or extension services.
Acreage and average fuel loadings should be estimated. The U.S. Soil
Conservation Service should be able to provide some of this information.
Average fuel loadings and organic emission factors for various wastes are
provided in Section 2.4 of AP-42. In some cases, agricultural burning may
be reported under residential open burning.
4.7.3 STRUCTURE FIRES
Building fires can also produce short term emissions of organic com-
pounds. The best procedure for determining information for this source
category is to contact local fire departments, fire protection associations,
or other agencies for an estimate of the number of structural fires in each
county during the year. In the absence of such information, assume an
average of six fires per 1,000 people each year.68
4.7.4 ORCHARD HEATERS
In areas where frost threatens orchards, heaters may be used in cold
portions of the growing season. County or state agriculture departments
will often have data on the number and types of orchard heaters in use.
Data can also be obtained from some of the citrus grove operators in the
area. These sources should also be able to furnish the periods of time the
units are fired during the year. An estimate should also be obtained of the
number of units fired at any one time. These data may be used to determine
heater hours of operation. Emission factors for orchard heaters are presented
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in Chapter 6 of AP-42. Since the use of heaters does not coincide with the
usual months of high ozone formation, this source will be of little concern.
However, in some locales, fueled heaters may be left in the fields for major
portion of the year. This practice will increase evaporative emissions and
should be accounted for in the inventory.
References for Chapter 4.0
1. AEROS Manual Series, Volume I; AEROS Overview, EPA-450/2-76-001,
U.S. Environmental Protection Agency, Research Triangle Park, NC,
February 1976.
2. 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.
3. AEROS Manual Series, Volume III: Summary and Retrieval, Second
Edition, EPA-450/2-76-009a, U.S. Environmental Protection Agency,
Research Triangle Park, NC, July 1977.
4. Hydrocarbon Control Strategies for Gasoline Marketing Operations,
EPA-450/3-78-017, U.S. Environmental Protection Agency, Research
Triangle Park, NC, April 1978.
5. Design Criteria for Stage I Vapor Control Systems for Gasoline Service
Stations, U.S. Environmental Protection Agency, Research Triangle Park,
NC, November 1975.
6. Nonattainment Workshop presented by The Florida Department of
Environmental Regulation at the University of Central Florida, Orlando,
FL, June 28-29, 1979.
7. W. H. Lamason, "Analysis of Vapor Recovery for the Gasoline Marketing
Industry", Pinellas County Department of Environmental Management,
Clearwater, FL, December 1979. Unpublished.
8. Highway Statistics, U.S. Department of Transportation, Federal
Highway Administration, Washington, DC. Annual publication.
9. 1977 Census of Retail Trade, Bureau of the Census, U.S. Department
of Commerce, Washington, DC.
10. Compilation of Air Pollutant Emission Factors, Third Edition and
Supplements, AP-42, U.S. Environmental Protection Agency, Research
Triangle Park, NC, August 1977.
11. Emission Inventory for Enforcement of New Source Review Policies,
EPA Contract No. 68-01-4148, Pacific Environmental Services, Inc.,
Santa Monica, CA, April 1979.
4-44
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12. Florida Oxidant SIP Assistance. Phase I; VOC Emissions Inventory,
EPA-904-9/-79-029a, U.S. Environmental Protection Agency, Atlanta,
GA, February 1979.
13. Emission Inventories for Urban Airshed Model Application in Tulsa
Oklahoma, EPA-450/4-80-021, Monitoring and Data Analysis Division, U.S.
Environmental Protection Agency, Research Triangle Park, NC,
September 1980.
14. Tampa Bay Photochemical Oxidant Study; Assessment of Anthropogenic
Hydrocarbon and Nitrogen Dioxide Emissions in the Tampa Bay Area,
EPA-904/9-77-016, U.S. Environmental Protection Agency, Atlanta, GA,
September 1978.
15. Volatile Organic Compound Species Data Manual, EPA-450/4-80-015,
U.S. Environmental Protection Agency, Research Triangle Park, NC, July
1980.
16. Control Techniques for Volatile Organic Emissions from Stationary
Sources, EPA-450/2-78-022, U.S. Environmental Protection Agency,
Research Triangle Park, NC, May 1978.
17. Control of Organic Emissions from Perchloroethylene Dry Cleaning
Systems, EPA-450/2-78-050, U.S. Environmental Protection Agency,
Research Triangle Park, NC, December 1978.
18. W. H. Lamason, "Technical Discussion of Per Capita Emission Factors
and National Emissions of Volatile Organic Compounds for Several Area
Source Emission Inventory Categories", Monitoring and Data Analysis
Division, U.S. Environmental Protection Agency, Research Triangle Park,
NC, July 1980. Unpublished.
19. End Use of Solvents Containing Volatile Organic Compounds,
EPA-450/3-79-032, U.S. Environmental Protection Agency, Research
Triangle Park, NC, May 1979.
20. Control of Volatile Organic Emissions from Solvent Metal Cleaning,
EPA-450/2-77-022, U.S. Environmental Protection Agency, Research
Triangle Park, NC, November 1977.
21. County Business Patterns, U.S. Department of Commerce, Bureau of the
Census, Washington, DC. Annual publication.
22. Control Techniques Guideline for Architectural Surface Coatings,
EPA Contract No. 68-02-2611, Acurex Corporation, Mountain View, CA,
February 1979.
23. Emission Inventory/Factor Workshop, Volume II, EPA-450/3-78-042b,
U.S. Environmental Protection Agency, Research Triangle Park, NC, May
1978.
4-45
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24. Control of Volatile Organic Emissions from Existing Stationary
Sources, Volume II; Surface Coating of Cans, Coils, Paper, Fabrics,
Automobile and Light-Duty Trucks, EPA-450/2-77-008, U.S. Environmental
Protection Agency, Research Triangle Park, NC, May 1977.
25. Air Pollution Engineering Manual, Second Edition, AP-40, U.S.
Environmental Protection Agency, Research Triangle Park, NC, May 1973.
Out of print.
26. Written communication from Bill Lamason, to Chuck Mann, Monitoring and
Data Analysis Division, U.S. Environmental Protection Agency, Research
Triangle Park,. NC, September 1980.
27. Control of Volatile Organic Emissions from Existing Stationary Sources,
Volume VI: Surface Coating of Miscellaneous Metal Parts and Products,
EPA-450/2-78-015, U.S. Environmental Protection Agency, Research
Triangle Park, NC, June 1978.
28. Control of Volatile Organic Emissions from Existing Stationary
Sources, Volume VIII; Graphic Arts - Rotogravure and Flexography,
EPA-450/2-78-033, U.S. Environmental Protection Agency, Research
Triangle Park, NC, December 1978.
29. Control of Volatile Organic Compounds from Use of Cutback Asphalt,
EPA-450/2-77-037, U.S. Environmental Protection Agency, Research
Triangle Park, NC, December 1977.
30. Steve Leung, et al., "Air Pollution Emissions Associated with Pesticide
Applications in Fresno County", California Air Resources Board Report
No. 77-E-02, Eureka Laboratories, Inc., Sacramento, CA, December 1978.
31. F. J. Wiens, A Methodology for Reactive Organic Gas Emissions
Assessment of Pesticide Usage in California, (Draft Interim Report),
California Air Resources Board, 1977.
32. Development of Questionnaires for Various Emission Inventory Uses,
EPA-450/3-78-122, U.S. Environmental Protection Agency, Research
Triangle Park, NC, June 1979.
33. Official Airline Guide, Rueben H. Donnelly Corporation, Oak Brook,
IL. Semi-monthly publication.
34. Airport Activity Statistics for Certified Route Air Carriers.
Federal Aviation Administration, U.S. Department of Transportation,
Washington, DC. Annual publication.
35. Air Pollutant Emission Factors for Military and Civil Aircraft,
EPA-450/3-78-117, U.S. Environmental Protection Agency, Research
Triangle Park, NC, October 1978.
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36. FAA Air Traffic Activity, Federal Aviation Administration, U.S.
Department of Transportation, Washington, DC, 1970.
37• Military Air Traffic Activity Report. Federal Aviation Administration,
U.S. Department of Transportation, Washington, DC, 1970.
38. Census of U.S. Civil Aircraft, Federal Aviation Administration,
U.S. Department of Transportation, Washington, DC, 1970.
39. Mineral Industry Surveys, "Sales of Fuel Oil and Kerosene", Bureau of
Mines, U.S. Department of the Interior, Washington, DC. Annual
publication.
40. Census of Population, Bureau of the Census, U.S. Department of
Commerce, Washington, DC. Decennial publication.
41. Minerals Yearbooks, Bureau of Mines, U.S. Department of the Interior,
Washington, DC. Annual publication.
42. Boating; A Statistical Report on America's Top Family Sport, The
National Association of Engine and Boat Manufacturers, Greenwich, CT.
Annual publication.
43. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment
Using Internal Combustion Engines, APTD-1490 through APTD-1496,
U.S. Environmental Protection Agency, Research Triangle Park, NC, 1972-
1974.
44. Area Management Reports, GE-20 Series, Corps of Engineers, U.S.
Department of the Army, New Orleans, LA, 1970.
45. Waterborne Commerce of the United States, Corps of Engineers, U.S.
Department of the Army, New Orleans, LA, 1970.
46. J.R. Pearson, "Ships as Sources of Emissions", Presented at the
Annual Meeting of the Pacific Northwest International Section of the
Air Pollution Control Association, Portland, OR, 1969.
47. Census of Agriculture, Bureau of the Census, U.S. Department of
Commerce, Washington, DC, 1969.
48. 1978 National Emissions Data System (NEDS) Fuel Use Report, Monitoring
and Data Analysis Division, U.S. Environmental Protection Agency,
Research Triangle Park, NC, October 1980. Unpublished.
49. 1970 Census of Housing, "Detailed Housing Characteristics", HC-B
Series, Bureau of the Census, U.S. Department of Commerce, Washington
DC, 1970.
50. Local Climatological Data; Annual Summary with Comparative Data,
U.S. Department of Commerce, Washington, DC. Annual publication.
4-47
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51. R.J Black, et al., The National Solid Waste Survey: An Interm Report,
U.S. Public Health Service, Rockville, MD, 1968.
52. National Survey of Community Solid Waste Practices; Interim Report,
U.S. Department of Health, Education and Welfare, Cincinnati, OH, 1968.
53. National Survey of Community Solid Waste Practices: Preliminary Data
Analysis, U.S. Department of Health, Education and Welfare, Cincinnati,
OH, 1968.
54. Ronald J. Brinkerhoff, "Inventory of Intermediate Size Incinerators
in the United States - 1972", Pollution Engineering, 5(11):33-38,
November 1973.
55. OAQPS Data File of Nationwide Emissions, 1971, Monitoring and Data
Analysis Division, U.S. Environmental Protection Agency, Research
Triangle Park, NC, May 1973. Unpublished report.
56. Standard Industrial Classification Manual, Office of Management and
Budget, Washington, DC, 1972.
57. "Steam Electric Plant Air and Water Quality Control Data for the
Year Ended December 31, 19 ", Federal Power Commission Form 67.
58. "Natural Gas Companies Annual Report", Federal Power Commission
Forms 2 and 2-A.
59. 1977 Census of Manufacturers: Subject Series, "Fuels and Electric
Consumed", U.S. Department of Commerce, Washington, DC, 1977.
60. Development of a Methodology To Allocate Liquid Fossil Fuel Consumption
by County. EPA-450/3-74-021, U.S. Environmental Protection Agency,
Research Triangle Park, NC, March 1974.
61. Fuel Trades Fact Book, New England Fuel Institute, Boston, MA, 1973.
62. Coal - Bituminous and Lignite, Bureau of Mines, U.S. Department of
Interior, Washington, DC, 1970.
63. 1970 Census of Housing, "Advance Report", Series HC-(Vl), Bureau of
the Census, U.S. Department of Commerce, Washington, DC, 1971.
64. Mineral Industry Surveys, "Sales of LPG and Ethane", Bureau of
Mines, U.S. Department of the Interior, Washington, DC. Annual
publication.
65. Mineral Industry Surveys, "Natural Gas Production and Consumption",
Bureau of Mines, U.S. Department of the Interior, Washington, DC, 1970.
4-48
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66. G. Ozolins and R. Smith, A Rapid Survey Technique of Estimating
Community Air Pollution Emissions, 999-AP-29, U.S. Department of
Health, Education and Welfare, Cincinnati, OH, October 1966.
67. Wildfire Statistics, Forest Service, U.S. Department of Agriculture,
Washington, DC. Annual publication.
68. Statistical Abstract of the United States, Bureau of the Census, U.S.
Department of Commerce, Washington, DC. Annual publication.
4-49
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5.0 INVENTORY METHODS FOR HIGHWAY VEHICLES
Highway vehicle emissions can be inventoried with data obtained from
the transportation planning process which is required in larger urban areas.
EPA's Office of Transportation and Land Use Policy (OTLUP) is responsible
for EPA policy on conducting highway vehicle emission inventories. Guidance
is under preparation and will become Chapter 5 of this report. In the
interim, for further information contact:
Director
Office of Transportation and
Land Use Policy
ANR-443
401 M Street, SW
Washington, DC 20460
5-1
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6.0 EMISSION CALCULATIONS
After planning and data collection, the third basic step in the inven-
tory is the calculation of emissions. This involves (1) an analysis of the
point and area source data collected by the procedures outlined in the
proceeding two chapters and (2) the development of emissions estimates for
each source. In some cases, test data will be supplied by the source.
However, in most instances the agency will have to compute emissions using
emission factors or material balance considerations. The following three
sections discuss the making of emission estimates based on source test data,
material balances, and emission factors.
In cases where no data have been obtained for certain point sources,
the agency may choose to "scale up" the inventory to account for these
missing sources indirectly rather than spend extra effort in an attempt to
get the necessary information directly from each source. Techniques for
accomplishing this are presented in Section 6.4.
Because reactive, rather than total, VOC emissions are needed in inven-
tories used in ozone control programs, nonreactive VOC must be excluded from
the emission totals for each source category. Section 6.5 of this chapter
presents procedures for excluding nonreactive VOC from the inventory.
Section 6.6 discusses the seasonal adjustment of annual emission inven-
tories. Seasonally adjusted inventories are of interest because higher
ozone concentrations are generally associated with the warmer months of the
year, and because VOC emissions from some sources vary seasonally. Thus,
since most inventories are developed for an annual period, seasonal adjust-
ment may be desirable to emphasize the relative importance of VOC emissions
during the warmer months constituting the ozone season.
A necessary element in any control program is the projection inventory
showing anticipated emissions at some future date(s). Generally, at least
two such projection inventories are required: baseline and control strategy.
More may be required if multiple strategies or alternate growth scenarios
are to be evaluated. The calculation of projection year emissions is dis-
cussed in Section 6.7.
6.1 SOURCE TEST DATA
In many cases, the most accurate method of estimating a source's emis-
sions is to use test data obtained by the agency or supplied by the plant
itself. The use of source test data reduces the number of assumptions that
need be made by the agency regarding the applicability of generalized emis-
sion factors, control device efficiencies, equipment variations, or fuel
characteristics. A single source test or series of tests, taken over a
sufficiently long time to produce results representative of conditions that
would prevail during the time period inventoried, will normally account for
most of these variables. The most nearly complete type of source testing is
continuous monitoring.
6-1
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Most source test reports summarize emissions for each pollutant by
expressing them in terms of (1) a mass loading rate (weight of pollutant
emitted per unit time), (2) an emission factor (weight of pollutant emitted
per unit of process activity), or (3) in terms of a flue gas concentration
(weight or number of moles of pollutant per some weight or volume of flue
gas). Generally, when a mass loading rate or emission factor is provided,
the resulting emission estimates can be easily calculated. For example, if
the average VOC emission rate for the time period tested was 12 Ibs/hr, and
the source operated for 16 hrs/day, 350 days/year, daily emissions would be
12 x 16, or 192 Ibs, and the annual emissions would be 192 x 350, or 67,200
Ibs (34 tons). Or, if an emission factor of 5 Ibs of VOC per ton of product
was given, and the plant produced 160 tons of product per day for 200 days
per year, annual emissions would be 5 x 160 x 200, or 160,000 Ibs (80 tons).
If the source test results are expressed in terms of VOC concentrations,
the emission calculations are more detailed. As an example, assume that
volatile organic compound emissions are expressed as parts per million, as
shown in Table 6.1-1. In this case, the concentration measurements and the
flow rate measurements are used to obtain mass loading rates. (A formula
for determining mass loading rates is shown as part of the calculations in
Table 6.1-1.) Note that in this example, the results are expressed as
methane, and a molecular weight of 16 Ibs/lb-mole is used in the mass load-
ing rate formula. If the concentration was expressed in terms of another
organic reference compound, the appropriate molecular weight would be used.
Upon determining the mass loading rate (0.3 Ibs/hr, in this example), this
rate can be divided by the production rate at the time of testing to yield
an emission factor of 0.1 Ibs VOC emitted per ton of production. After
averaging the individual mass loading rates and emission factors determined
for all runs of the source test, the resulting average mass loading rate or
emission factor can be multiplied by the annual operating time or annual
production, respectively, to determine annual emissions. Emissions can be
calculated similarly for other time periods.
points should be noted when using source test data to calculate
Emissions. First, because source tests are generally only conducted over
several hours or days, at most, caution is urged when using these data to
estimate emissions over longer time intervals or for conditions different
from those under which the tests were performed. Adjustments may be needed
to account for differing conditions. Second, a source test supplied by a
plant may not adequately describing a given facility's annual or seasonal
operating pattern. In cases where such data are not included in the test
reports, an operating rate will have to be obtained in order to make reliable
annual or seasonal emission estimates. This is best done by contacting the
plant and obtaining operating information for the period the test was con-
ducted. Such information could be obtained from questionnaire data but may
not be as accurate.
6-2
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Source Test Results
Run Number
Date
Stack flow rate (scfm)
% Excess air
CO emissions (ppm, by volume)
VOC emissions
(ppm, by volume, as CH.)
8-5-71
9840
225
2.5
11.9
8-6-71
8510
227
6.4
6.8
8-7-71
10290
366
4.6
10.9
Process Conditions
Production rate (tons/hour) 3.0 3.2 3.1
Calculation of VOC Emissions
Conversion formula:
Ib VOC/hr = 1.58 x M x 10~7 x ppm x SCFM
Where M = molecular weight of reference VOC
Calculation for Run 1:
Mass loading rate = 1.58 x 16 x 10~ x 11.9 x 9840 =0.3 Ib/hr
Emission factor =0.3 Ib/hr x 1 hr/3 tons production
= 0.1 Ib VOC/ton production
Table 6.1-1. Example Source Test Data and Emission Calculations
6-3
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6.2 MATERIAL BALANCE
If source test results are not available, the agency can, in some
cases, use material balance considerations to estimate emissions. In fact,
for some sources, a material balance is the only practical method to esti-
mate VOC emissions accurately. Source testing of low level, intermittent,
or fugitive VOC exhaust streams can be very difficult and costly in many
instances. Emissions from solvent evaporation sources are most commonly
determined by the use of material balances.
Use of a material balance involves the examination of a process to
determine if emissions can be estimated solely on knowledge of specific
operating parameters and material compositions. Although the material
balance is a valuable tool in estimating emissions from many sources, its
use requires that a measure of the material being "balanced" be known at
each point throughout the process. If such knowledge is not available, and
is therefore assumed, serious errors may result.
In the VOC emission inventory, a material balance is generally used to
estimate emissions from solvent evaporation sources. This technique is
equally applicable to both point and area sources. The simplest form of
material balance is to assume that all solvent consumed by a source process
will be evaporated during that process. For instance, the assumption is
reasonable that, during many surface coating operations, all of the solvent
in the coating evaporates to the atmosphere during the drying process. In
such cases, emissions simply are equal to the amount of solvent applied in
the surface coating (and added thinners) as a function of time. As another
example, consider a dry cleaning plant that uses Stoddard solvent as the
cleaning agent. To estimate emissions, the agency needs only to elicit from
each plant the amount of solvent purchased during the time interval of
concern, because emissions are assumed equal to the quantity of solvent
purchased.
The assumption that makeup solvent equals emissions also holds in
certain more complicated situations. If a nondestructive control device
such as a condenser or adsorber is employed, this assumption is valid to the
extent that the captured solvent is returned to the process. Similarly, if
waste solvent reclamation is practiced a plant, by distillation or "boil-
down", this assumption will be applicable. Both of these practices simply
reduce the makeup solvent requirements of an operation and commensurately,
the quantity of solvent lost to the atmosphere.
In the above discussion, the material balance is simplified because of
the assumption that all of the consumed solvent evaporates and is emitted to
the atmosphere. Situations exist where such an assumption is not always
reasonable. For example, if a destructive control device such as an after-
burner, incinerator, or catalytic oxidation unit is employed on the process
exhaust, any VOC emissions will be either destroyed or so altered that one
could not reasonably assume, without testing the exhaust downstream of the
device, the characteristics and quantities of any remaining VOC material.
As another example, degreasing emissions will not equal solvent consumption^
if the waste solvent is sold to a commercial reprocessor. In such a situation,
6-4
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emissions will be the difference of solvent consumed and solvent in the
waste sent to the reprocessor. As still another example, some fraction of
the diluent used to liquify cutback asphalt is believed not to evaporate
after application, but rather, it is retained in the pavement. The above
examples show that, if one assumes total evaporation of all consumed solvent,
overestimation of emissions will result in many cases.
Several other situations can complicate the material balance. First,
not all of the solvent losses from certain operations such as drycleaning or
degreasing occur at the plant site. Significant quantities of solvent may
be evaporated, instead, from the waste solvent disposal site, unless the
waste solvent is incinerated or disposed of in a manner, such as deep well
injection, that precludes subsequent evaporation to the atmosphere. Gener-
ally, one can assume that much of the solvent sent to disposal sites will
evaporate. The fact that some solvent associated with various operations
evaporates at the point of disposal rather than at the point of use should
be determined, as these losses may occur outside of the area covered by the
inventory.
Material balances cannot be employed in some evaporation processes
because the amount of material lost is too small to be determined accurately
by conventional measurement procedures. As an example, applying material
balances to petroleum product storage tanks is not generally feasible,
because the breathing and working losses are too small, relative to the
total average capacity or throughput, to be determined readily from changes
in the amount of material stored in each tank. In these cases, AP-42
emission factors developed by special procedures, will have to be applied.1
6.3 EMISSION FACTORS
One of the most useful tools available for estimating emissions from
both point and area sources is the emission factor. An emission factor is
an estimate of the quantity of pollutant released to the atmosphere as a
result of some activity, such as combustion or industrial production, divided
by the level of that activity. In most cases emission factors are expressed
simply as a single number, with the underlying assumption being that a
linear relationship exists between emissions and the specified activity
level over the probable range of application. Empirical formulas have been
developed for several source categories that allow the agency to base its
emission estimates on a number of variables instead of just one. The most
important VOC emitters for which a number of variables are needed to calcu-
late emissions are highway vehicles and petroleum product storage and hand-
ling operations. As a rule, the most reliable emission factors are those
based on numerous and representative source tests or on accurate material
balances.
The use of an emission factor to estimate VOC emissions from a source
necessitates that the agency have complete source and control device infor-
mation. In many cases, including most combustion sources, the emission
calculation merely involves the multiplication of the appropriate emission
factor by the source activity, such as fuel combustion, for the time interval
in question. If a control device is in place, an adjustment factor equal to
6-5
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(1-fractional control device efficiency) should be multiplied by the uncon-
trolled emission estimate to account for the effect of the device. In AP-
42, as in most cases, emission factors typically represent uncontrolled
emissions or emissions before any control device.
When empirical formulas are available, more detailed computations may
be needed to estimate emissions. As mentioned above, highway vehicles and
petroleum product handling and storage operations are sources for which a
number of variables must be considered in the emission calculations. ^The
following is a sample calculation for an external floating roof tank.
Problem
Estimate the total annual evaporative loss, in pounds per year, given
the following information:
Tank description: Welded, external floating roof tank in good
condition; mechanical shoe primary seal; 100 ft.
diameter; tank shell painted aluminum color.
Stored product: Motor gasoline; Reid vapor pressure, 10 psi;
6.1 Ibs/gal liquid stock density; no vapor or
liquid composition given; 1.5 million bbl/yr
average annual throughput.
Ambient conditions: 60°F average annual ambient temperature;
10 mi/hr average annual wind speed at tank
site; assume 14.7 psia atmospheric pressure.
Solution
Standing Storage Loss - Calculate the standing storage loss from
Equation 6.3-1 below:
L (Ib/yr) = K VnP*DM K (Equation 6.3-1)
s
The variables in Equation 6.3-1 can be determined as follows:
K =1.2 (from Table 6.3-1, for a welded tank with a mechanical
s shoe primary seal).
n =1.5 (from Table 6.3-1, for a welded tank with a mechanical
shoe primary seal).
V = 10 mi/hr (given).
V = (10)1-5 = 32.
n
T = 60°F (given).
T = 62.5°F (from Table 6.3-2, for an aluminum color tank in
s good condition and Ta = 60°F).
RVP = 10 psi (given).
6-6
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P =5.4 psia (from Figure 6.3-1, for 10 psi Reid vapor pressure
gasoline and T = 62.5°F).
s
P =14.7 psia (assumed).
cl
5.4
P* = 14.7 _
[ 1 + (1 - 5.4 )u.5]2
14.7
D = 100 ft (given).
M = 64 Ibs/lb-mole (typical value for gasoline) .
K =1.0 (given).
W = 5.1 Ibs/gal (approximated assuming W = 0.08
To calculate standing storage loss in Ib/yr, multiply the
the K , V11, P*, D, M , and K values, as in Equation 6.3-1.
L (Ibs/yr) = (1.2) (32) (0.114) (100) (64) (1.0) = 28,000 Ibs/yr
S
Withdrawal loss - Calculate the withdrawal loss from Equation 6.3-2
below:
L (Ib/yr) = (0.943) QCW1. (Equation 6.3-2)
W D
The variables in Equation 6.3-2 can be determined as follows:
Q = 1.5 x 106 bbl/yr (given).
C = 0.0015 bbl/1000 ft2 (from Table 6.3-3, for gasoline in a
steel tank with light rust) .
W» = 6.1 Ibs/gal (given).
D = 100 ft (given) .
To calculate withdrawal loss in Ib/yr, use Equation 6.3-2.
L (Ib/yr) = (0.943) (1.5x106) (Q.Q015) (6.1)= ^ ^/yr
w J.UD
Total Loss - Calculate the total loss from Equation 6.3.3 below:
L (Ib/yr) = L (Ib/yr) + Lw(lb/yr) (Equation 6.3-3)
L (Ib/yr) = (28,000) + (129) = 28,129 Ib/yr
The discussion on emission factors thus far has dealt with "activity
level emission factors", factors that relate emissions with some level of
production or capacity. This type of emission factor is generally the most
accurate, as it physically relates the most appropriate process parameters
with emissions. Another type of factor that can be of some use is the
emissions-per-employee factor. As briefly discussed in Chapters 3 and 4,
6-7
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emissions-per-employee factors are used to obtain crude emissions estimates
from sources for which little equipment, production, or other process infor-
mation is available in the point source inventory. Emissions-per-employee
factors represent a tool that can be used to "scale up" inventories to
estimate emissions from point sources for which no data are obtained.
Scaling up for inventory is discussed in the next section. Generally,
because of imprecision in using emissions-per-employee factors, techniques
that directly estimate emissions are considered preferable in most instances.
6.4 SCALING UP THE INVENTORY
The preceding sections describe general techniques for calculating
emissions based on data from questionnaries, source tests, and other methods.
Although information should be obtained directly from as many sources as
possible to enhance inventory accuracy, situations may arise where no data
can be gathered from some segment of a source category. The pharmaceutical
manufacturing industry is a case in point, with major manufacturers included
as point sources and the multitude of small operations, usually employing
less than 25 people, not even listed by many agencies. Auto refinishing
presents a similar problem since operations are carried out on a fairly
large scale by a few specialty shops and on a much smaller scale by numerous
auto body shops. In these cases, the inventory can be "scaled up" to
provide for a rough accounting of the missing emissions. To the extent that
the resulting emissions estimates are generally reported collectively,
scaling up can be considered an area source approach. Any VOC source
category is a potential candidate for scaling up.
The basic concept involved in scaling up an inventory is to use the
data that have been received through plant contacts to extrapolate emission
data for missing sources. The following formula shows the basic computation
involved for a particular source category.
Nonreported _ Reported Emissions _ Reported Emissions (Equation 6.4-1)
emissions ~ Coverage Fraction
Coverage fraction is a measure of the extent to which some indicator such as
employment, number of plants, production, or sales, is represented or
"covered" by the questionnaire responses. Since reported emissions are
known, and since nonreported emissions are sought in the above equation, the
problem becomes one of determining the most appropriate indicator that can
be used to estimate the fraction of coverage the agency's point source
inventory did obtain.
The most commonly used coverage indicator for scaling up the inventory
is the number of employees within pertinent Standard Industrial Classifi-
cation (SIC) codes.3 When employment within appropriate SIC categories is
used as a measure of coverage, the above equation is transformed into the
following relationship:
Nonreported = Reported Emissions x Total _ Reported Emissions
emissions ~ Reported Employment Employment (Equation 6.4-2)
6-10
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In Equation 6.4-2, the ratio of reported emissions to reported employment is
an emissions-per-employee factor. Equation 6.4-2 can be used in either of
two ways to estimate missing point source emissions.
The recommended way to use Equation 6.4-2 is to derive values of both
reported emissions and reported employment for each SIC category directly
from the local point source data base. One advantage of this approach is
that the resulting emissions-per-employee factors are tailored to the area
of concern. One potential disadvantage is that the resulting factors, if
based only on point source data, may not be representative of the smaller
sources to which these factors will generally be applied. An example of
this direct approach is given:
Example: Consider the situation of an area wherein five plants in SIC
3069 are coded as point sources, having combined annual
emissions of 685 TPY of VOC. Based on employment data coded
on the point source forms (or determined by plant contacts) ,
these five sources employ 3,250 workers. According to County
Business Patterns, 3529 persons are employed in SIC 3069
within the same area. Nonreported VOC emissions in SIC 3069
for this county can thus be calculated as:
TPY _
Nonreported emissions = [3244 employees3 X 38°8 emPloyees ~ 685 TPY
= 119 TPY
Hence, in this example, total emissions for the county in SIC 3069 would be
estimated as 804 TPY. VOC emissions for the other SIC categories would be
scaled up similarly. Note that in the above equation, the figure (685/3244)
is an emission-per-employee factor, equal to 0.211 ton/yr-employee .
The alternative to using values of reported emissions and employment
directly from the local point source inventory is to apply emissions-per-
employee factors that have been developed from inventory data in other
areas. Examples of where this has been done are given in References 4
through 6. Ranges of emissions-per-employee factors for the more important
industrial VOC sources are shown in Table 3.1-1 in Chapter 3. If, in the
above example, an emissions-per-employee factor of 0.21 had been used from
Table 3.1-1, Equation 6.4-2 then becomes:
Nonreported emissions = (0.21 TPY/employee x 3808 employees) - 685 TPY
=115 TPY
One distinct advantage of using "borrowed" emissions-per-employee factors is
that reported employment is not needed, which means that the technique can
be used even where employment data are not collected for each point source.
However, few emissions-per-employee factors are available in the literature,
and an agency generally does not know what specific operations are covered
by published factors. Hence, since the applicability of published emissions-
per-employee factors to an agency inventory may be questionable, the agency
should try to develop emissions-per-employee factors tailored to its own
particular area. Moreover, these factors should be developed at the four
digit level to prevent misapplication to employees not engaged in VOC
emitting operations.
6-11
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Regardless of whether locally developed or published emissions-per-
employee factors are used, estimates of total employment within each indus-
trial category are needed in order to use Equation 6.4-2. The most conven-
ient source of employment is the U.S. Department of Commerce's publication
County Business Patterns which summarizes employment, generally by county,
for SIC categories at the 2, 3, and 4 digit level.7 Other sources of indus-
trial listings include state departments of labor/industry and various
industrial directories. In some cases, employment in various categories
will be determined as part of the ongoing transportation planning process in
larger urban areas. The agency should determine which of these sources is
most current and appropriate for estimating industrial coverage within its
jurisdiction.
Extreme caution should be exercised when considering the emissions-per-
employee factor method. Any emissions-per-employee ratio approach is neces-
sarily somewhat crude, and should not be used to estimate the bulk of VOC
emissions in an area. If the scaled up emission totals determined by this
approach are significantly greater than the point source totals for the
corresponding SIC categories, consideration should be given to expending
more effort in the point source inventory, particularly for the more impor-
tant source categories. Care should also be taken that any scaling up does
not result in some inadvertent double accounting of emissions. Some portion
of the resulting scaled up emission totals already may be accounted for by
per capita emission factors or even by the application of other emission-
per-employee factors to the same source category.
6.5 EXCLUDING NONREACTIVE VOC FROM EMISSION TOTALS:
As was discussed in Section 2.2.6, a number of VOCs are considered
photochemically nonreactive and thus should be excluded from the inventory
used in the agency's ozone control program.8*9 These nonreactive compounds
are listed below:
Methane
Ethane
1,1,1-Trichloroethane (methyl chloroform)
Methylene chloride
Trichlorofluoromethane (CFG 11)
Dichlorodifluoromethane (CFG 12)
Chlorodifluoromethane (CFC 22)
Trifluoromethane (FC 23)
Trichlorotrifluoroethane (CFC 113)
Dichlorotetrafluoroethane (CFC 114)
Chloropentafluoroethane (CFC 115)
All of the above compounds, with the exception of methane and ethane,
are halogenated organics. Halogenated organics find principal applications
as metal and fabric cleaners, refrigerants, and propellants in aerosol
products.
A major industrial category employing these halogenated compounds is
degreasing, which is discussed in Section 4.3.2. To exclude these non-
reactive VOC from the degreasing emission totals, the agency should elicit
6-12
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information on the particular type of solvent used in each degreasing unit.
If information is obtained on the questionnaire or during the plant contact,
the agency should experience little difficulty excluding emissions of these
nonreactive solvents from the resulting emission totals.
More difficulty is encountered when excluding nonreactive VOC from
degreasers covered in the area source inventory, because numerous solvents
will comprise the emission total. Several alternatives are available for
determining an average degreasing solvent mix for area sources. One way is
simply to summarize the solvent usage from the point source inventory and to
apply the resultant mix to the area source total. Another alternative would
be to conduct a brief survey of small degreasing facilities in the area. If
either of these approaches is followed, a separate solvent mix should be
determined for cold cleaning units and vapor degreasers and applied accord-
ingly to the emission total for each degreasing category. If these proce-
dures prove unworkable, nationwide data may be utilized. As an average, 75
percent of the solvent used in small cold cleaners is reactive, whereas only
about 60 percent of the solvent used in vapor degreasing is reactive.10
Because these averages may vary considerably from area to area and with
time, local solvent mix data should be used, if reasonably available.
A small percentage of dry cleaning establishments use trichlorotri-
fluoroethane (fluorocarbon 113) as a fabric cleaning solvent. Information
on the type of solvent used at each dry cleaning plant should be obtained
during plant contacts so that fluorocarbon 113 emissions could be directly
excluded. If dry cleaners are treated as area sources in the inventory,
local survey results or other data will be needed to determine the fraction
of total cleaning solvent in the area that is fluorocarbon 113. Nationwide,
fluorocarbon 113 is only used in about 5 percent of the coin operated units,
and accounts for only about 0.4 percent of total annual dry cleaning solvent
consumption.11 Hence, in most situations, little error is involved if all
dry cleaning solvent is assumed to consist of perchloroethylene and petroleum
solvents.
Refrigerants represent the largest application for fluorocarbons. The
major fluorocarbons used in refrigerators, freezers and air conditioners are
fluorocarbon 11, 12 and 22.12 Because these are all nonreactive, emissions
associated with refrigerant use need not be included in the VOC inventory
used in an ozone control program.
Until the ozone layer controversy, the largest percentage of fluoro-
carbons were used as aerosol propellants. Methylene chlpride is also used
as a propellant in aerosol products. Aerosol propellant use can be accounted
for in the VOC inventory by using the per capita factor suggested in Section
4.3.7. Much of the propellent used in aerosol products is comprised of
nonreactive halogenates, and should not be included in the inventory.12>13
The agency should be aware of several other end uses 'of these halogen-
ated compounds that may be encountered in a VOC inventory. The bulk of all
trichloroethane is used for metal cleaning, but a small fraction is found in
polishes and waxes. This use is also discussed in Section 4.3.7. Simi-
larly, methylene chloride is not only used for degreasing and in aerosol
6-13
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products, but is also used in paint removal operations and in the pharmaceu-
tical industry. Likewise, fluorocarbons are also used as blowing agents to
increase the insulation properties of urethane foams and used in plastic
materials. To the extent that emissions from these various processes are
known to be comprised of nonreactive VOC, they should be excluded from the
inventory.12>13
All combustic.1 sources emit methane and lesser amounts of ethane.
Since source test data are generally not available for most combustion
sources, to estimate the nonreactive fraction the agency will have to apply
typical VOC species profiles to each source category. VOC profiles for many
source categories are shown in Reference 14. An example VOC profile from
this reference.is shown in Table 6.5-1, representing industrial, natural gas
fired, reciprocating internal combustion engines. Based on Table 6.5-1, 76
percent and 10 percent by weight of all VOC emitted from this type of com-
bustion are methane and ethane, respectively. All of the other compounds
are photochemically reactive. Hence, total emissions from this source would
have to be multiplied by the quantity [l-(.76 + .10)], or 0.14, to determine
the fraction that is reactive and that should be included in the inventory.
Methane and ethane emissions can be excluded from other sources in the same
manner. In general, no halogenated organics are emitted from combustion
processes, hence, methane and ethane are the only two compounds to be
considered for exclusion from the VOC inventory when dealing with combustion
sources.
6.6 SEASONAL ADJUSTMENT OF THE ANNUAL INVENTORY
Most VOC emission inventories have traditionally contained estimates of
annual emissions. Hence, all procedures, emission factors, correction
factors, and activity levels employed in the inventory have been developed
to represent annual average conditions. However, because high photochemical
ozone levels are generally associated with the warmer months of the year,
and because VOC emissions from some sources vary seasonally, the relative
importance of VOC emissions should be determined during the warmer months
constituting the ozone season.
A seasonally adjusted VOC inventory can be developed in various ways.
One approach is to compile a separate inventory expressly for a typical day
during the ozone season. This could entail the development of specific
questionnaires, methodologies, seasonal emission factors, and correction
factors, for that typical day. This approach, while representing the
ideal, would require more resources than are commonly available, especially
if an annual inventory has already been compiled.
A more reasonable alternative is to use the existing annual inventory
but, for the most important source categories, to adjust those variables
affecting emissions to reflect conditions that prevail during the ozone
season. This approach provides much of the seasonal specificity of the
"typical day" inventory and does so with a minimal amount of effort.
Because adjusting the existing annual inventory is preferable in many cases
to developing an additional ozone season specific inventory, techniques for
making such an adjustment are described below.
6-14
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The basic procedure for adjusting the annual inventory involves iden-
tifying those variables that influence emissions seasonally and substituting
appropriate values that reflect conditions during the ozone season. Gener-
ally many parameters influence emissions as a function of time. Two of the
most important variables are (1) source activity and (2) temperature.
6.6.1 SEASONAL CHANGES IN ACTIVITY LEVELS
Source activity for several important categories fluctuates signifi-
cantly on a seasonal basis. Because VOC emissions are generally a direct
function of source activity, seasonal changes in activity levels should be
examined at the more important sources in the inventory. As an example,
Vehicle Miles Traveled (VMT) may increase in the summer in certain locations
due to increased vacation or other travel, possibly leading to somewhat
higher VOC emissions from highway vehicles during the summer months. Because
of the importance of highway vehicles in many areas, the agency should
determine VMT during the ozone season and should use this seasonal rate,
rather than an annual average, for estimating emissions in the inventory.
Similarly, the agency should determine if the activity at other important
sources changes significantly throughout the year. Other operations that
might be more active in the warmer months or, in some cases, active only
during the warmer months, include exterior surface coating, asphalt paving,
gasoline handling and storage, power plants, open burning, and pesticide
applications. On the other hand, some sources, due to summer vacation
shutdowns or decreased demand for product, may be less active during the
ozone season. Many sources, particularly industrial facilities, will show
no strong seasonal change in activity. Little adjustment needs to be made
in these cases to estimate the seasonal emissions component.
6.6.2 SEASONAL CHANGES IN TEMPERATURE
Another important variable is temperature, especially in that emissions
from two of the most important VOC emission sources - highway vehicles and
petroleum product handling and storage operations - are significantly influ-
enced by temperature changes. As an example, breathing losses from fixed
roof storage tanks increase at higher temperatures.
The following empirical formula from Section 4.3 in AP-42 shows the
dependence of these losses on temperature.
LB = 2.21 x 10-* M [ izj_p I0-68 Dl-73 H0-51 AT0-50 FpCKc
Where: L,, = Fixed roof breathing loss (Ib/day)
B
M = Molecular weight of vapor in storage tank (Ib/lb mole)
P = True vapor pressure at bulk liquid conditions (psia)
D = Tank diameter (ft)
H = Average vapor space height, including roo.f volume
correction (ft); See note (1) below
AT = Average ambient temperature change from day to night
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F = Paint factor (dimensionless)
C = Adjustment factor for small diameter tanks
(dimensionless)
K = Crude oil factor (dimensionless); See note (2) below
c
Note 1: The vapor space in a cone roof is equivalent in
volume to a cyclinder which has the same base
diameter as the cone and is one third the height
of the cone.
Note 2: K = (0.65) for crude oil, K = (1.0) for gasoline
C C.
and all other liquids.
Note in the above formula, that P, the true vapor pressure for a typical
gasoline (RVP = 10), ranges from about 5.2 psia at a bulk liquid temperature
of 60°F to 8.1 psia at 85°F. Hence, the term [P/(14.7-P)]°-68 varies from
about 0.66 to 1.15 over this range of bulk liquid temperatures. (Be aware
that bulk liquid temperatures typically will exceed average ambient temper-
atures by several degrees, depending on tank color.2) This increase of
about 70 percent demonstrates that evaporation potentially can be much more
significant at higher summer temperatures. Thus, to adjust the inventory to
estimate breathing loss emissions from fixed roof storage tanks during the
ozone season, the agency should incorporate the appropriate temperature into
the above formula to account for increased evaporation during warmer months.
Temperature effects have to be accounted for in other petroleum product
marketing and storage operations, as well. The effects of temperature on
emissions from these other sources are also presented in Chapter 4 of AP-42.
The reader should note that the empirical formulas for calculating storage
tank losses are subject to change as a result of continuing testing programs.
Hence, the most current AP-42 supplements should be consulted prior to
making any storage tank calculations.
6.6.3 OTHER SEASONAL ADJUSTMENT CONSIDERATIONS
While source activity and temperature are two of the most important
variables in determining seasonal fluctuations in the VOC emission inventory,
other variables may be significant in certain instances. As an example, the
use of air conditioning affects the magnitude of emissions from highway
vehicles. As another example, emissions from floating roof tanks storing
gasoline will depend on wind speed as well as on the Reid Vapor Pressure
(RVP) of the gasoline. Typically, gasolines will have lower RVP in the
summer, which tends to offset the increase in emissions expected if temper-
ature were the only variable considered in the seasonal adjustment.1^
For many sources, no major seasonal fluctuations in emissions are
expected, due to changes in process variables or ambient conditions. For
example, some industrial surface coating operations such as metal parts
painting may use the same amount of solvent in their operations in each
season of the year. For these sources, no seasonal adjustment is necessary
and the annual emission rate may be assumed equal to the emission rate
during the ozone season.
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6.7 EMISSION PROJECTIONS
Projection inventories are needed by an agency to determine if a given
area will achieve or exceed the ozone standard in future years. There are
two basic types of projections, baseline and control strategy. Baseline
projections are estimates of future year emissions that take into account
both expected growth in an area and air pollution control regulations in
effect at the time the projections are made. Included are regulations which
have been adopted and will take effect at a future date. Control strategy
projections, on the other hand, are estimates of future year emissions that
also include the expected impact of changed or additional control regulations.
Baseline projection inventories of annual countywide emissions for the
particular years of interest will probably not be available from past inven-
tory efforts. Moreover, whatever projection inventories that do exist may
not reflect all of the growth and control scenarios that the agency may wish
to evaluate. Hence, the agency will have to devote resources to the develop-
ment of projection year inventories. Specific recommendations for making
projections are discussed in the following sections. These general consider-
ations should be kept in mind from the outset of inventory planning:
1. To a large extent, projection inventories will be based on fore-
casts of industrial growth, population, land use, and transportation. The
air pollution agency should not attempt to make these forecasts but, rather,
should rely on the local Metropolitan Planning Organization (MPO), Regional
Planning Commission (RPC), or other planning agencies to supply them. This
course has several advantages. First, it would be extremely costly^for the
air pollution agency to duplicate the forecasts made by other planning
agencies. Second, the air pollution agency needs to base its emission
projections on the same forecasts as to other governmental planning agencies.
This consistency is necessary to foster the credibility of any proposed
control programs based on emission projections.
2. Anticipated control strategies being considered in the modeling
area should be known in order to design projection inventories to reflect
these strategies. This consideration may influence the type of data col-^
lected as well as the structure of the inventory itself. As an example, if
the agency wants to test the effect of applying Stage I controls on tank
trucks unloading only to service stations above a particular size, it may be
desirable to treat these particular stations as point sources rather than
lumping them in a general service station area source category.
3. It is important that all emissions projected for future years be
based on the same methodologies and computation principles as the base year
emissions. For example, if a traffic model is used for estimating travel
demand for the base year, the same traffic model should be applied to esti-
mate travel demand for projection years. Use of the same methodology
assures consistency between base year and projection year emission estimates
and prevents possibly spurious inventory differences from changes in methodology.
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4. Projection inventories will always be open to attack because of
their somewhat speculative nature. The technical credibility of emissions
projections will be a function of their reasonableness, of the amount of
research and documentation of assumptions, and of the procedures or method-
ologies used to make the projections. Some degree of uncertainty will
always accompany emission projections. This fact should be acknowledged
openly. The art of projecting emission inventories is not in eliminating
uncertainty, but in learning how to minimize it. Internal and external
review of emission inventory projections will improve their technical
quality and enhance their credibility.
6.7.1 MAJOR POINT SOURCE PROJECTIONS
The best approach for projecting emissions from major point sources is
to obtain information on each facility. This type of projections informa-
tion would ideally be determined by contacting plant management, but it
could be solicited on questionnaires. Generally, questionnaires would not
be sent out solely to obtain projection information, but this additional
information may be elicited on questionnaires used in periodic updates of
the baseline inventory. Permit applications submitted to various Federal,
state, and local agencies should also be screened to get information on
expected expansion or new construction. In addition, the local metropolitan
planning organization and other planning bodies should be contacted for any
information they may have on projected industrial expansion and for comment
on the reasonableness of any plans submitted by plant personnel.
Once this type of projected plant growth information is obtained, the
agency needs to determine what regulations will apply in order to estimate
controlled emissions. In the baseline projection, existing applicable
regulations would be assumed and evaluated. For instance, a fossil fuel
power plant now under construction and expected to start operation in two
years would be subject to Federal New Source Performance Standards (NSPS)
for particulate, S02 and NOX. Hence, unless plant personnel indicated that
more stringent controls will be applied, the resulting emissions could
reasonably be assumed to be equal to the standard. Similarly, the effects
of any alternate standards would have to be evaluated. Since emission
standards are commonly expressed in terms of emission factors, mass loading
rates, or concentrations, the procedures outlined earlier in this chapter
can be followed to estimate controlled emissions.
When obtaining projection information from plant management, the
agency should inquire if the indicated increase in activity will occur at
the existing facility, at another existing plant, or at a new plant. If
growth will occur at an existing facility, the agency also needs to deter-
mine if it will be expansion to existing capacity or will require plant
modifications to increase capacity. These considerations are especially
important for major sources, since in certain areas new emissions may be
limited by growth allocations. They will also help the agency to determine
what additional control measures are likely to be required. The completion
dates of any expansion or new construction are also needed in order to
determine if a given source will impact on the projection inventory.
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As an example of making point source projections for specific sources,
consider a facility employing a large open top vapor degreasing operation
that emitted 100 tons of solvent per year in 1977, based on an annual pro-
duction of 10,000 units of a particular metal part. Assume that no control
measures are being taken to reduce solvent losses from the process. Suppose
a plant contact is made, and it is learned that 5 percent more metal parts
will be produced per year until 1982 using the existing operation, and that,
in 1986, a replacement facility will be brought on line at another location
to produce 20,000 parts per year. Moreover, suppose that the source is
located in an ozone attainment area where RACT is not required on VOC
sources. To estimate VOC emissions from this source for a 1982 projection
inventory, one could assume that, since no additional controls are expected,
the current emission level can be multiplied by the cumulative growth rate
in metal parts production (i.e., 5 years at 5 percent/year = [1.05]5 =
1.28, or 128 percent) to estimate 1982 VOC emissions. In this manner,
emissions for 1982 can be estimated at 128 percent of 100, or 128 tons per
year, and the point source record for this projection year should be adjusted
take this growth into account.
Continuing this example, suppose a control strategy projection is
desired for 1987 to evaluate the effect of RACT as an alternate control
strategy. In this case, both growth and controls must be considered. As a
first approximation, if a similar open top vapor degreasing operation is
used in the new facility, one can assume that, since 1987 production is
twice 1977 production, uncontrolled emissions from the replacement plant
will be twice those of 1977, or 200 tons per year. Since the new plant will
be subject to RACT in this control scenario, VOC emissions will be reduced
45 to 60 percent from the uncontrolled case.10Hence, projected emissions in
1978 would be only 80 to 110 tons per year, depending on which RACT measures
were instituted. Note that, since the replacement facility is to be built
between 1977 and 1987, a new point source should be included in the 1987
projection inventory, and the old source deleted or assigned zero emissions
in the projected year.
As is obvious from this example, even when projection information is
available for specific facilities, certain assumptions will have to be made
to project emission levels for some future year. For instance, in the 1982
baseline projection, it was assumed that emissions would increase propor-
tionately with production. Depending on the nature of the operation, this
may not be entirely accurate. This same assumption, along with an assumed
emission reduction due to RACT, was also used in making the 1987 control
strategy projection. This underscores the point made previously that
projections are somewhat speculative in nature.
6.7.2 AGGREGATE POINT SOURCE PROJECTIONS
In many instances, projection information will not be available on
every facility in an area of interest. Some plant managements will not be
willing or able to provide forecasts of their corporate plans, especially
for distant years. In addition, many plants in certain source categories,
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such as small industrial boilers, will be too small and too numerous to
warrant the individual solicitation of projection information. In these
situations, other procedures need to be employed to project future emissions.
Two possible approaches are discussed below.
In the case of large point sources, projection information may be
available on many sources within a given category, but for various reasons,
may not be obtainable for one facility or several. For example, 10 paint
manufacturing plants may operate in the area of interest, but successful
contacts may have been made to only eight of these. In this situation, a
reasonable approach to projecting growth and emissions at the remaining two
plants would be to evaluate the growth trends in the plants for which
projections are known and to apply them to the plants for which no infor-
mation is available. In the example of the paint manufacturing plants, if
production were expected to expand by 6 percent per year, on average, for
the eight plants, then this rate could be applied to the two plants to
estimate expected growth. Then, knowing the increase in production, the
appropriate control measures would be considered in making a baseline
projection. Good engineering judgement is needed in this practice to screen
out any unreasonable projections that may occur.
For smaller points sources, obtaining projection information from each
plant may not be feasible. In these cases, the rate of activity growth may
be assumed equivalent to that of some surrogate indicator for which projec-
tions have been made by local MPOs or by OBERS.16 For example, one might
assume that cold cleaning operations would grow at the same rate as indus-
trial manufacturing, which can, in turn, be estimated from projections of
employment in industrial manufacturing categories.
Regardless of what surrogate indicators are used for making projections,
the basic calculations are the same. The ratio of the value of the surrogate
indicator in the projection year to its value in the base year is multiplied
by the aggregate base year activity level for the point source category in
the base year. Because the projection years of interest to the air pollution
control agency will not often be the years for which growth projections have
been made, interpolation of projection year data may be required. Local
planning agency input should be sought regarding whether straight line or
other interpolation methods should be employed.
6.7.3 AREA SOURCE PROJECTION PROCEDURES
Two approaches can be used for making growth projections of area
source emissions. The more accurate approach involves projecting the
activity levels themselves. The more common approach, however, involves the
use of surrogate growth indicators to approximate the increase or decrease
of each activity level.
The first of these approaches is generally employed when a local
survey has been made or when other local estimates projecting growth in
specific areas are available. For example, if a survey of dry cleaners has
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been performed, and the average growth in the modeling area is projected to
be 5 percent per year, then in 5 years, dry cleaning activity would increase
by 28 percent.* As another example, a local asphalt trade association may
be may be able to project area cutback asphalt use in a future year. When
considering such estimates, the inventorying agency must recognize the
possibility of deliberate or inadvertent biases, through wishful thinking or
self serving motives, and it should strive to obtain opinions which are as
objective as possible. Moreover, the agency should be careful to determine
whether or not such estimates of future activity levels anticipate the
effect of control measures. This is important, as some estimates may be
used more appropriately in control strategy projections than in the baseline
inventory. Any such projections should be consistent with projections made
by other planning agencies.
A common alternative to projecting activity levels directly is to use
indicators of growth. In the context of projections, a surrogate growth
indicator is one whose future activity is fairly certain and is assumed to
behave similarly to the specific activity levels of interest. The most
commonly used surrogate growth indicators are those parameters typically
projected by a local MPO such as population, housing, land use and employment,
As one example, the quantity of consumer/commercial solvent use in a projec-
tion year might be assumed to grow proportionaly with population. Hence, if
population in an area increased by 10 percent from the base year through
the projection year, consumer/commercial solvent use could be assumed to
increase by 10 percent, as well. Regardless of what variables are used as
growth surrogates, the basic calculation is the same: the ratio of the
value of the growth indicator in the projection year to its value in the
base year is multiplied by the area source activity level in the base year
to yield the projection year activity level.
In making area source emission projections, control measures will have
to be considered for certain source categories. The effects of controls on
area sources can generally be simulated by changes in either (1) emission
factors or (2) activity levels, depending on the source and the nature of
the control measure(s) being considered. As an example of the first of
these approaches, RACT for gasoline service stations could be accounted for
by using an emission factor lower than the uncontrolled factor given in
AP-42.17 As an example of the second approach, RACT for cutback asphalt
paving could be evaluated by simply reducing the activity level in propor-
tion to the fraction of cutback asphalt that would be replaced with
emulsified asphalt. °
Projection information on several area source categories is summarized
in Table 6.7-1.
*(1.05)b 1.28, or a 28 percent increase
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TABLE 6.7-1. Growth Indicators for Projecting Emission Totals
for Area Source Categories19
Source Category
Gasoline handling
Drycleaning
Degreasing
Non-industrial
surface coating
Cutback asphalt
Pesticide
applications
Miscellaneous solvent
use
Growth Indicators
Gasoline demand,
vehicle use (VMT),
or population
Population, retail
service employment
Industrial employment
Population or residential
dwelling units
Consult industry and local
road departments
Agricultural operations
Population
Information Sources
U.S. Department of
Transportation,
State Transportation
Agency, State Tax
Agency, Local MPO
or Reference 20
Solvent supplier,
trade association
Trade association
Local MPO
Consult industry and
local road departments
State department of
agriculture, local
MPO
Local MPO
Aircraft, commercial,
and general
Aircraft, Military
Agricultural equipment
Construction
equipment
Industrial equipment
Projections should be
done case by case -
Projected land use maps
may be useful
Estimate on individual
Agricultural land use,
agricultural employment
Heavy construction employ-
ment (SIC code 16)
Industrial employment
(SIC codes 10-14, 20-39,
and 50-51) or industrial
landuse area
Local airport
authority, MPO,
state aviation
system plan
Local airport author-
ities and appropriate
military agencies
Local MPO
Local MPO
Local MPO
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TABLE 6.7-1.
(cont.). Growth Indicators for Projecting Emission Totals
for Area Source Categories
Source Category
Lawn and garden
equipment
Off highway motor-
cycles snowmobiles,
and small pleasure
crafts
Railroads
Ocean-going and
river cargo vessels
Residential fuel
combustion
Commercial/industrial
fuel combustion
Industrial fuel
combustion
Solid waste disposal,
on site incineration,
open burning
Fires: Managed
burning agri-
cultural field
burning, frost
control (orchard
heaters)
Fires: forest
wildfires,
structual fires
Growth Indicators
Single-unit housing
or population
Population
Revenue ton—miles
Cargo tonnage
Residential housing
units or population
Commercial/insti-
tutional employment,
population, or land
use area
Industrial employment
(SIC codes 10-14,
20-39, and 50-51) or
industrial land use
Based on information
gathered from local
regulatory agencies
Based on anticipated
local regulations as
indicated by inform-
ation sources
Difficult to project
see Chapter 4
Information Sources
Local MPO
Local MPO
References 21, 22
Local port authorities,
U.S. Maritime Administr-
ation, or U.S. Army Corps
of Engineers
Local MPO and
Reference 23
Local MPO, land use
projections
Local MPO, land use
projections
6-24
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6.7.4 PROJECTION REVIEW AND DOCUMENTATION
Because the projection inventories are so important in control strategy
development, they should be reviewed in draft form by the air pollution
control agency and as many other involved groups as possible. The projection
inventories will survive this careful scrutiny if all assumptions, proce-
dures and data sources are carefully documented. This review and document-
ation process will help assure that the projections are (1) consistent with
any other projections being made in the area, (2) objective and not biased
toward any particular policy, etc., (3) open, with all assumptions, and
estimates clearly stated for public review, and (4) defensible because of
all of the above.
The key aspects of projections that will invite criticism are: (1)
which indicators are used for projecting activity level growth, (2) when and
where this growth will occur, and concomitantly, whether it will be by expan-
sion of existing facilities or by new construction, and (3) what emissions
will be associated with this growth, either in the baseline case or as a
result of various candidate control strategies. When planning, compiling
and reviewing the point source projection inventory, the agency should focus
particular attention on these issues.
It is especially important that consistent methodologies be used for
the base year and the projection years to estimate emissions for each
source. For example, if emissions from gasoline evaporation at service
stations in a base year are estimated as a result of a special study, such
as questionnaires to individual service stations, it would be inconsistent
to estimate such emissions for a future year based on projected VMT. Such
inconsistencies likely will lead to changes in emissions estimates that are
due not to growth or control measures but, rather, to changes in the inven-
tory procedures themselves.
A test to determine if the various base year and projection year
methodologies are mutually consistent is to judge whether each projection
year methodology, if applied to the base year data, would result in a
replication of the base year emission totals. If significant discrepancies
are found, then one methodology should be chosen to apply to both years.
Generally, in this regard, any methodology which applies growth factors to
the base year total to estimate projection year emissions or activity
levels will meet this consistency criterion.
References for Chapter 6.0
1- Compilation of Air Pollution Emission Factors, Third Edition and
Subsequent Supplements, AP-42, Standards, U.S. Environmental Protection
Agency, Research Triangle Park, NC, August 1977.
2- Evaporation Loss from External Floating-Roof Tanks. Second Edition, API
Publication 2517, American Petroleum Institute, Washington, DC,
February 1980.
6-25
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3. Standard Industrial Classification Manual, Executive Office or the
President, Office of Management and Budget, Washington, DC, 1972.
4. Lew Heckman, "Organic Emission Inventory Methodology for New York and
New Jersey," presented at the Emission Inventory/Factor Workshop,
Raleigh, NC, September 13-15, 1977.
5. Malesh C. Shah and Frank C. Sherman," A Methodology for Estimating VOC
Emissions From Industrial Sources," paper presented at the 71st Annual
Meeting, American Institute of Chemical Engineers, November 1978.
6. Methodology for Inventoring Hydrocarbons, EPA-600/4-76-013, U.S. Environ-
mental Protection Agency, Research Triangle Park, NC, March 1976.
7. County Business Patterns, Bureau of the Census, U.S. Department of
Commerce, Washington, DC, Annual.
8. Recommended Policy on the Control of Volatile Organic Compounds, 42 FR
35314, July 8, 1977.
9. Clarification of Agency Policy Concerning Ozone SIP Revisions and
Solvent Reactivities, 44 FR 32042, June 4, 1979, 45 FR 32424, May 16,
1980, and 45 FR 48941, July 22, 1980.
10. Control of Volatile Organic Emissions from Solvent Metal Cleaning,
EPA-450/2-77-022, U.S. Environmental Protection Agency, Research
Triangle Park, NC, November 1977.
11. Control Techniques for Volatile Organic Emissions From Stationary
Sources, EPA-450/2-78-022, U.S. Environmental Protection Agency,
Research Triangle Park, NC, May 1978.
12. David M. Pitts, Emissions Control Options for the Synthetic
Organic Chemicals Manufacturing Industry, Knoxville, TN, EPA Contract
Number 68-02-2577, Hydroscience, Inc., June 1979.
13. End Use of Solvents Containing Volatile Organic Compounds, EPA-450/3-
79-032, U.S. Environmental Protection Agency, Research Triangle Park,
NC, May 1979.
14. Volatile Organic Compounds Species Data Manual, EPA-450/3-78-119,
U.S. Environmental Protection Agency, Research Triangle Park, NC,
December 1978.
15. E. M. Shelton, Motor Gasolines. Winter 1978-79, BETC/PPS-79/3, U.S.
Department of Energy, Bartlesville, OK, July 1979.
16. "Regional Economic Activity in the U.S.", 1972 OBERS Projections,
Bureau of Economic Affairs, U.S. Department of Commerce, and Economic
Research Services, U.S. Department of Agriculture, 1974.
6-26
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17. Hydrocarbon Control Strategies for Gasoline Marketing Operations,
EPA-450/3-78-017, U.S. Environmental Protection Agency, Research
Triangle Park, NC, December 1977.
18. Control of Volatile Organic Compounds from Use of Cutback Asphalt,
EPA-450/2-77-037, U.S. Environmental Protection Agency, Research
Triangle Park, NC, December 1977.
19. Procedures for the Preparation of Emission Inventories for Volatile
Organic Compounds, Volume II, EPA-450/4-79-018, U.S. Environmental
Protection Agency, Research Triangle Park, NC, September 1979.
20. Energy Outlook 1978-1990, Exxon Company, Houston, TX, May 1972.
21. Annual Railroad Reports prepared for the U.S. Interstate Commerce
Commission.
22. Yearbook of Railroad Facts, Association of American Railroads,
Washington, DC. Annual publication.
23. U.S. and World Energy Outlook Though 1990, Projection Interdependence,
U.S. Congressional Research Service, Washington, DC, November 1977.
6-27
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7.0 SUPPORTING DOCUMENTATION AND REPORTING
The final phase in the development of an emission inventory is to
present the data which has been collected, compiled and analyzed. The data
can be presented in a variety of forms, from unorganized raw data listings
to aggregated summary reports. Generally, the form in which the data will
be presented is determined by (1) how the data can be most efficiently
summarized, and, more importantly, (2) why the inventory was conducted.
Documentation supporting the VOC inventory is a necessary part of all
summary reports. However, the degree of documentation, like the reporting
format, will also depend on the end use of the inventory data. In this
chapter, some examples of both inventory data presentation and documentation
will be discussed, as well as how inventory end uses can determine both the
presentation and the documentation.
7.1 REPORTING FORMS
The purpose of the emission inventory is the primary consideration when
deciding on a reporting format. An inventory developed only for research
purposes can be presented in many forms. For example, a raw data listing,
which basically presents the data compiled in the inventory, could consist
simply of computer printouts of sources and emissions. The printouts would
require no additional preparations for agency internal use.
On the other hand, reports which are for use outside an agency will
usually be more formal than reports for internal use. External use reports,
such as public information pamphlets and emissions control program documents,
require formating which clearly presents summarized inventory data. Since
these reports summarize the inventory data, they are referred to as summary
reports.
A summary report includes information that has been aggregated and
organized in some manner during the reporting process. For instance, a
summary report of total VOC emissions from all dry cleaners in an area would
of necessity involve a totaling of emission estimates stored in certain file
records. In many instances, some analysis of the data might also be per-
formed in the process of preparing a summary report. A more formal summary
report will convey the inventory information to the document reader clearly
and concisely.
An example of formal, inventory reports are State Implementation Plan
(SIP) submissions or other control strategy inventory reports. These reports
must meet formating requirements set fourth in local, state and EPA regulations,
Because requirements may differ for each agency as well as for different
years, the most recent Federal Register or local administrative code should
be consulted when reporting control program inventories. As a guide, the
reporting format required in the 1982 State Implementation Plan submittals
for VOCs is shown in Table 7.1-1.
7-1
------- An error occurred while trying to OCR this image.
-------
To compile and report detailed point source data, the example in Figure
7.1-1 can be followed. This format is designed to report emissions from
specific processes for each facility inventoried as a point source. Process
emission points which can be used in completing Figure 7.1-1 are listed in
Appendix B. Use of this table will provide the reader with an accounting of
point source emissions which appear in Table 7.1-1.
In addition to required reporting formats, a wide variety of tables and
graphic displays can be employed to present inventory data. Charts, tables
and graphs can quickly convey to the reader emissions breakdowns by industries,
geographical areas, or source size. Emission trends and the effects of
control programs can also be tabulated or graphed. Several examples of
tables and graphs are included here to provide some ideas on how data can be
presented.
Figure 7.1-2 is an example of a pie chart to illustrate the relative
importance of VOC emission sources. Figure 7.1-3 is an example of how to
show the relative importance of sources by bar graphs. Note that projection
year emissions can be compared with base year emissions. Figure 7.1-4, an
expansion of a sub part of Figure 7.1-3, provides the reader with a detailed
breakdown of organic solvent emissions by source type. Other figures and
tables may be used if they illustrate the particular characteristics of an
emission inventory.
How the inventory data can most efficiently be summarized will depend
on time and manpower available to assemble a report. Tabular reports are
the most common kind of report, as they can be readily generated from comput-
erized inventory systems. Certain types of graphic displays, on the other
hand, are difficult to produce using a computer and require time and manpower
to develop by hand. Most of the NEDS raw data and summary reports available
to the public are of the tabular variety. The various NEDS reporting programs
are described in limited detail in Appendix F, and in greater detail in
Reference 1.
Summary inventory data tables, together with raw data listings of
equipment, activity levels, and emissions from individual sources, constitute
the most frequently used reports in the development and implementation of an
ozone control program. Because there exists a need at certain levels to be
able to compare baseline inventories from one area to another, as well as to
determine the impact of employing various control strategies, such as RACT,
a common format is considered desirable to promote reporting consistency.
The format presented in Table 7.1-1 is required when reporting VOC emissions
in 1982 SIPs.^This format allows the agency to identify all major source
categories of volatile organic compound emissions and to determine the
reductions that may occur in an area if various control strategies are
employed.
7.2 SUPPORTING DOCUMENTATION
Documentation of the emission inventory is highly useful for all VOC
inventory uses. While inventories developed for inhouse use may not require
the same degree of documentation as inventories used in State Implementation
7-3
-------
Principal Emitting Operations at Major
VOC Source Categories
Flat Tire, Inc.
Name and Location 100 Bias Beltway, Whitewall, WI
Major VOC Source Category Rubber Tire Manufacturing
Emissions
Principal Operations (tons/year)
Undertread and Sidewall Cementing 610
Other Tread and Sidewall Preparation
Bead Dipping 52
Tire Building 200
Tread End Cementing 96_
Green Tire Spraying 643
Tire Curing 13
Solvent Mixing 10
Solvent Storage 10
Other (milling) 6
TOTAL 1646
Figure 7.1-1. Example Use of Point Source Process Emissions Reporting Table
7-4
------- An error occurred while trying to OCR this image.
-------
VOLATILE ORGANIC COMPOUND EMISSION TRENDS
1100
1000
900
800
700
k.
I 600
I
"? 500
400
300
200
100
-
^
-
(5
^m
r
IB
i
K
J
1
F
E
D
A
H
C
B
L
K
J
1
F
A
H
G
B
L
K
J
1
*
F
E
D
A
SOURCE CATEGORY :
L - OTHER MOTOR VEHICLE
-
K - LIGHT DUTY AUTO
J- AIRCRAFT
1- OFF HIGHWAY MOBILE SOURCES -
H - BURNING OF MATERIALS
G - COMBUSTION OF FUELS
F - OTHER ORGANIC COMPOUNDS _
EVAP. (ORGANIC SOLVENTS)
E - GASOLINE DIST.
D -PETROLEUM REFINERY EVAP.
C - OTHER IND./COMM.
B- CHEMICAL
A - PETROLEUM REFINERY
1980
1990
2000
Figure 7.1-3. Example bar chart to illustrate source category contributions to total emissions
and projected emission trends.
-------
Figure 7.1-4
BREAKDOWN OF ORGANIC SOLVENT EMISSIONS BY
SOURCE TYPE
350 -
300
250
200 -
150 •
100
50
n
M
L
K
J
I
H
G
F
E
D
C
B
A
M-OTHER ORGANIC EVAPORATION
Lr PRINTING
K- PLASTIC FABRICATION
J- RUBBER FABRICATION
I - OTHER SOLVENTS -I
DRY CLEANERS
H-PERC J
G-DEGREASERS
F- WATER BASE
COML & COM. COATINGS
E-SOLVENT BASE
D-WATER BASE
INDUSTRIAL COATINGS
C-SOLVENT BASE
B-OTHER ORGANIC COMP. 1
A-SOLVENT Jb.UKAUt.MN^
7-7
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Plans, good documentation of all inventories will help an agency when more
formal inventories must be developed. Therefore, compiling and maintaining
documentation in support of data are recommended in all emission inventories.
Documentation entails keeping a record of all methods, assumptions,
example calculations, references, and results employed in the compilation
effort. The goal of documentation is to be able to explain to both the
agency and outside users (1) how the inventory was compiled and (2) how
reliable the inventory is.
The following documentation items are suggested as information which
will achieve these inventory goals.
A. Background information should be presented on reasons for compiling
the inventory, its future uses, how it evolved, and the significance of
changes from emissions of previous years. The source/receptor relationship
used for ozone control strategy development should be specified.
B. The geographic area covered by the inventory shall be specified.
This may be a county, air basin, AQCR, etc. A map depicting the area should
be included.
C. Population, employment and economic data used in projections
should be presented. This includes data used in calculating emissions with
per capita emissions and emissions-per-employee factors (see Item H).
D. The time interval represented by the emission inventory should be
specified (e.g., annual, seasonal, hourly, etc.).
E. Traffic data for the inventory area should be summarized and
presented. Documentation should include descriptions of procedures and
models used in estimating the following: VMT, traffic speeds, miles of
roadway for each roadway classification, hot and cold start percentages, hot
soak and in transit emissions, average annual miles driven by vehicle model
year, vehicle age distribution, traffic parameters for local (off network)
traffic, traffic parameters for roadway outside of the transportation
planning area but inside the inventory area, and any other parameters which
significantly affect the highway vehicle emissions calculations.
F. Note any proposed or promulgated control strategy programs that
will affect the baseline inventory. In control strategy inventories, graphs
and tables to illustrate progress toward air quality goals should be included.
G. Baseline emission estimates should be summarized by source category
in tabular format. These emission estimates should exclude nonreactive VOC.
1. Source categories for which the emissions are negligible
should be listed as "Neg".
7-8
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2. Source categories for which there are no emissions in the
study area should be listed as "0".
H. A narrative should also be presented for each category of the
inventory. The narrative should contain at least the following:
1. Procedures used to collect the data - Procedures should be
presented which describe completely how the data were collected and
analyzed. A concise point source/area source definition should also be
included.
2. Sources of the data - A complete description of the types of
sources accessed in the course of compiling the inventory should be
presented. These sources would include, for example, permit files,
inspection reports, source test data, actual company inquiries, other
agencies, etc. A statement should be included assessing the complete-
ness of the data collected.
3. Copies of questionnaires - Samples of questionnaires mailed
to various source categories for the collection of data should be
included as part of the inventory documentation.
4. Questionnaire statistics - Statistics regarding the question-
naires should be presented. This information may include:
a. The number of questionnaires sent
b. The number for which response was received
c. The method of extrapolating available information for
nonrespondents
d. Any assumptions made regarding the data received or not
received.
5. Emission factor citation - Emission factors used for the cal-
culation of emissions should be clearly stated. Factors from sources
other than AP-42 may be used but a rationale for the use of these other
factors should be provided. Source test data are preferred over
emission factors.
6. Method of calculation - Sample calculations for each type
of computation should be presented, to allow for an independent verifi-
cation of the computations. (Some emission factors are "frequently
misused.) Techniques for excluding nonreactive VOC from the inventory
should be described
7. Assumptions - Any assumptions made in any part of the pro-
cedures should be clearly stated.
8. Items not included - Any sources of emissions which are not
included in the inventory should be itemized in the narrative. A
statement as to why these sources were excluded should be presented.
Possible reasons for exclusion could be:
7-9
-------
a. The emissions from these sources are known to be negligible
b. No emission factors exist, and no source test data are avail-
able to allow computation of these emissions
c. Emissions from these sources have been taken into account by
considering a background ozone concentration
9. A list of references should be included as a final section of
the narrative.
Some examples of the above documentation items are included in Appendix
E. Additional items should be included in the inventory documentation, if
they will further clarify and support the inventory.
Once an inventory is well documented and is technically sound, it can
be useful for several years with only annual updating. In certain cases,
adequate documentation may allow the agency to forego an update of certain
portions of the inventory, so that more resources can be devoted to higher
priority items in an ozone control program.
Technically correct and documented inventories are always in the best
interest of all air pollution management agencies.
References for Chapter 7.0
1. AEROS Manual Series, Volume III; Summary and Retrieval, Second
Edition, EPA-450/2-76-009a, U.S. Environmental Protection Agency,
Research Triangle Park, NC, July 1977.
2. Emission Inventory Requirements for 1982 Ozone State Implementation
Plans, Draft, EPA-450/4-80-016, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1980.
7-10
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APPENDIX A - GLOSSARY OF IMPORTANT TERMS
Activity level: Any variable parameter associated with the operation of a
source (e.g., production rate, fuel consumption, etc.) that may be
correlated with the air pollutant emissions from that source.
AP-42: EPA Document Number AP-42, Compilation of Air Pollutant Emission
Factors, Environmental Protection Agency, Research Triangle Park, North
Carolina. Supplements are published regularly. This document includes
process descriptions and emission factors for a broad range of criteria
pollutant emission sources.
Area source: Normally, an aggregation of all sources not defined as point
sources in a specific geographic area. Area sources ususally include
all mobile sources and any stationary sources too small, difficult, or
numerous to classify as point sources. The area source emissions are
assumed to be spread over a broad area.
Baseline projection: Estimate of emissions expected in future years, based
on a growth and emission control scenario. Baseline emission controls
for a given projection year include only those controls that have been
legally mandated at the time of preparing the projection.
Breathing loss: Loss of vapors from storage tanks due to diurnal warming
and cooling.
Control strategy projection inventory: An inventory of emissions, for a
future year, which differs from the baseline inventory in that it takes
into account the expected impact of a proposed control strategy.
Correction factors: Special multipliers employed in emission calculations
to more accurately adjust the resulting emission estimates to take into
account special parameters such as temperature, pressure, operating
load, etc. Appropriate correction factors are particularly important
in accurately calculating organic emissions from mobile sources and
petroleum product storage and handling operations.
Degreasing: Any operation in which impurities such as greases and oils are
removed from a surface using an organic solvent.
Diffusion modeling: A mathematical technique for calculating the atmospheric
distribution of air pollutants based on emissions data and meteoro-
logical data for an area. Also referred to as dispersion modeling.
Documentation (inventory): Refers to a compilation of the methods, assump-
tions, calculations, references, etc., that are employed in the develop-
ment of an inventory.
Dry cleaning: The practice of cleaning textile materials by treatment with
organic solvents. The most common dry cleaning solvents are perchloro-
ethylene and Stoddard.
A-l
-------
Emission factor: An estimate of the rate at which a pollutant is released
to the atmosphere as the result of some activity, divided by the rate
of that activity (e.g., production rate).
Emission inventory: A compilation of information relating to sources of
pollutant emissions, including location, quantity of emissions number
and type of control devices, stack dimensions and gas flow rates, and
additional pertinent details.
Empirical Kinetic Modeling Approach (EKMA): A source/receptor relationship
developed by EPA for estimating the overall reduction of volatile
organic compound levels needed in an urban area based on existing
oxidant levels and VOC/NOx ratios.
Evaporative losses: Emissions caused by the vaporization of materials
(generally solvents) at normal atmospheric temperatures and pressure
conditions.
Exhaust gas: Any gas, along with any particulate matter and uncombined
water contained therein, emitted from a source to the atmosphere.
Fugitive organics: Organic compounds from a source that are not emitted
through stacks, vents, or other confined air streams.
Gasoline marketing operations: The operations and systems associated with
the transportation of gasoline from refineries to bulk terminals, to
bulk storage, to dispensing outlets, and to vehicle gas tanks.
Gridding and subcounty allocation: The practice of distributing emissions
or any other parameter from a larger geographical area (usually a
county) to a smaller geographic area (i.e., a grid) using data presumed
to be proportional to the parameter being distributed.
Hydrocarbons: Any compounds containing only carbon and hydrogen. The term
"hydrocarbon" is often used synonymously with "volatile organic compounds",
although the latter also includes hydrocarbon derivatives, as well.
Imprecision, emission inventory: That error in an emission inventory due
to the variability (or random error) in the data used in determining
the inventory.
Inaccuracy, emission inventory: That error in an emission inventory due to
omissions, errors, and biases in the data used in determining the
inventory.
Inventory: A compilation of source, control device, emissions, and other
information relating to sources of a pollutant or group of pollutants.
Land use ->rojection: Estimate of land use in a future year (often given in
terms of land use maps representing the projected conditions).
A-2
-------
Material balance: Technique used to estimate emissions from a source by
accounting for the weights of one or more substances in all incoming
and outgoing process streams.
Methane: The simplest hydrocarbon species; often excluded from VOC measure
ments or inventories because it is essentially unreactive in atmo-
spheric photochemical reactions.
Mobile source: Any moving source of air pollutants, such as automobiles,
vessels, locomotives, aircraft, etc.
Motor vehicles: Motor powered vehicles such as automobiles, trucks, motor-
cycles and buses, operated primarily on streets and highways.
National Emission Data System: An automatic data processing system developed
by EPA for storage and retrieval of source and emission data.
Nitric oxide (or nitrogen oxide): One of the two oxides of nitrogen
which are collectively referred to as NOX (q.y.). The amount of nitric
oxide (NO) in NOx is often reported in terms of the quivalent weight of
nitrogen dioxide (N02), in which case its true weight is only 30/46 of
the reported weight.
Nitrogen dioxide: One of the two oxides of nitrogen which are collectively
referred to as NOx (q.v). The total weight of NOX is often reported
"as Nitrogen dioxide (N02)", which is not the true weight of the
mixture but the weight which would be attained if all the nitric oxide
(NO) were converted to N02.
Nonmethane: Excluding methane (CH^).
Nonmethane hydrocarbon: All hydrocarbons, or all VOC, except methane.
Office of Business Economics, Research Service (OBERS): Acronym used in
reference to projections prepared jointly by the U.S. Department of
Commerce, Bureau of Economic Affairs, Office of Business Economics and
the U.S. Department of Agriculture, Economic Research Service, for the
U.S. Water Resources Council, April 1974.
Oxides of nitrogen: In air pollution usage, this comprises nitric oxide
(NO) and nitrogen dioxide (N02); usually expressed in terms of the
equivalent amount of N02.
Ozone: Three atoms of oxygen (03) combined through complex photochemical
reactions involving volatile organic compounds and oxides of nitrogen;
the principal chemical component of the photochemical oxidant formed in
photochemical air pollution.
Ozone control strategy: A plan developed by an agency to control ambient
ozone levels within its jurisdiction.
A-3
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Ozone precursors: Volatile organic compounds and oxides of nitrogen, as air
pollutant emissions and as air contaminants, undergo a series of reactions
under the influence of ultraviolet light from the sun, to form photo-
chemical oxidants, including ozone.
Ozone season: That period of the year during which conditions for photochem-
ical ozone formation are most favorable. Generally, sustained periods
of direct sunlight (i.e., long days, small cloud cover) and warm temper-
atures .
Paraffins: Saturated, nonaromatic hydrocarbon compounds, also known as
long-chain alkanes.
Photochemistry:- The chemistry of reactions which involve light as the
source of activation energy.
Photochemical model (air quality): A detailed computer model that estimates
ozone concentrations both as a function of space and time by directly
simulating all of the physical and chemical processes that occur during
the photochemical process.
Point source: Generally any stationary sources for which individual records
are collected and maintained. Point sources are usually defined as any
facility which releases more than a specified amount of a pollutant.
Process variable: Any condition associated with the operation of a process,
including the quantities and properties of any materials entering or
leaving any point in the process, which is, or may readily be, monitored,
measured, etc., during the normal course of process operation.
Process weight rate: The process weight charged per unit of time. The term
is loosely used interchangeably with operating rate. However, operating
rate may cover either input to or output from a process whereas, strictly
speaking, process weight rate should cover only material input to a
process.
Reactivity: A measure of the rate and extent with which a volatile organic
compound will react, in the presence of sunlight and nitrogen oxides,
to form photochemical ozone.
RACT (Reasonably Available Control Technology): Reasonable available
control technology is defined as the lowest emission limit that a
particular source is capable of meeting by the application of control
technology that is reasonably available considering technical and
economic feasibility.
Seasonal adjustment: Used with reference to annual average rates of pollutant
emissions, this is the factor needed to calculate daily or hourly
average rates for one season (in the case of ozone, summer rates are
most commonly required).
A-4
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SIC Codes (Standard Industrial Classification Codes): A series of codes
devised by the Office of Management and Budget to classify establishments
according to the type of economic activity in which they are engaged.
SIP (State Implementation Plan) inventories: Emission inventories required
as part of the overall State Implementation Plan for achieving the
National Ambient Air Quality Standards. States are required under the
Clean Air Act to submit these plans to the U.S. Environmental Protection
Agency.
Solvent: Any organic compound, generally liquid, that is used to dissolve
another compound or group of compounds.
Source: Any person, device, or property that contributes to air pollution.
Source category: Any group of similar sources. For instance, all residential
dwelling units would constitute a source category.
Source (process) information: Information collected on each point source
in an inventory that describes the source, such as location, fuel use
and fuel characteristics, operational data, stack data, or other
identifiers. Source information, together with emissions and control
device data, comprise the basic elements of an emission inventory. For
area sources, this information is usually limited to activity levels.
Source/receptor model: A model or relationship that predicts ambient ozone
levels based on precursor emission strengths (of NOX and VOC) and
various meteorological parameters. Source/receptor models may range in
complexity from simple empirical or statistical relationships (such as
rollback or the Empirical Kinetic Modeling Approach [EKMA]) to detailed
photochemical atmospheric simulation models.
Source test: Direct measurement of pollutants in the exhaust stream(s) of a
facility.
Spatial resolution: The degree to which the location of a source can be
pinpointed geographically within an inventory area.
Species: With regard to VOC, a specific chemical which is part of a particular
volatile organic compound, such as methane, 2-hexene, 1,1,1-trichloroethane,
etc. With regard to NCx a species is either nitric oxide (NO) or
nitrogen oxide (N02).
Species class: Any grouping of VOC compounds, combined in accordance
with regulatory policy or rules specified by input instructions for a
photochemical simualtion model. Also called "reactive class" or
"reactivity class".
Stack parameters: Parameters characteristic of a stack and stack gases, as
required for input to some models. Typically included are stack
height, inner diameter, volume flow rate, and temperature of gas which
are needed to calculate effective stack height (i.e. stack height plus
plume rise).
A-5
-------
Stationary source: A source which remains at a fixed location while emitting
pollutants. Generally, any non-mobile source of air pollutants.
Surface coating: Operations involving the application of paints, varnishes,
lacquers, inks, fabric coatings, adhesives, and other coating materials.
Emissions of organic compounds result when the volatile portion of the
coating evaporates.
Surrogate indicator: (1) For spatial resolution, a quantiy for which distri-
bution over an area is known or accurately estimated which may be
assumed similar to the emissions distribution from some source category
for which spatial allocation is unknown. (2) For growth, a quantity
for which official growth projections are available which may be assumed
similar to that of activity in some source category for which projections
are needed.
Temporal resolution: (1) The process of determining or estimating what
emissions may be associated with various seasons of the year, days of
the week or hours of the day, given annual totals or averages. (2) A
measure of the smallest time interval with which emissions can be
associated in an inventory.
Transportation planning model: A system of computer programs which are used
in simulating the performance of existing and future transportation
systems in an urban area.
Urban Transportation Planning System: An urban transportation planning
battery of computer programs distributed jointly by the Urban Mass
Transit Administration and the Federal Highway Administration.
Vehicle miles traveled: An estimated total of number of miles traveled by
all vehicles, or by all vehicles of a given category, in a specified
region for a specified period of time; often used as a surrogate indi-
cator for spatial resolution of motor vehicle emissions.
Vehicle mix: Composition of vehicular traffic as determined by the fraction
of vehicle miles traveled by each class of vehicle.
Volatile organic compounds (VOC): Organic compounds include all compounds
of carbon except carbonates, metallic carbides, carbon monoxide, carbon
dioxide, and carbonic acid. A volatile organic compound (VOC) is any
organic compound that, when released to the atmosphere, can remain long
enough to participate in photochemical reactions. While there is no
clear line of demarcation between volatile and nonvolatile organics,
the predominant fraction of the VOC burden is compounds which evaporate
rapidly at ambient temperatures. Almost all organics which can be
considered VOC have vapor pressures greater than 0.1 mm of Hg at standard
conditions (20°C and 760 mm Hg).
Volume percent: The number of volumes of a given component in 100 volumes
of a mixture. In gaseous mixtures, equivalent to mole percent.
A-6
-------
Weight percent: The number of weight or mass units of a given component in
100 units of a mixture.
Zone: A subdivision of a study area, constituting the smallest geographic
area for which data are aggregated and basic analyses made.
A-7
-------
APPENDIX B - POINT SOURCE PROCESS EMISSION REPORTING FORMAT
EPA has proposed that 1982 ozone SIP emission inventories be reported
in the formats shown in Table 7.1-1 of Chapter 7 and Figure B-l of this
Appendix.1 In addition to presenting emissions in the format of Table 7.1-
1, point source emissions for each facility are to be reported by process.
This appendix will discuss the use of the process emissions listing in Table
B-l and its application to the point source reporting sheet shown in Figure
B-l.
Figure B-l should be used to report VOC emissions by process for an
identified point source. Completion of the Name and Location line is self
explanatory. The Major VOC Source Category should be listed as the major
operation carried out at a facility. For example, a major facility distri-
buting ethanol would be classified under Bulk Gasoline and VOC Terminals in
Table B-l. This classification would appear on the Major VOC Source Category
line in Figure B-l. The process emission points listed in Table B-l under
this classification (Vapor Collection Losses, Vapor Control Unit Losses,
etc.) would appear under Principal Operations in Figure B-l. Emission
estimates for these operations would be shown in the right column in Figure
B-l under Emissions.
While these reporting tables are not required for all inventories, use
of some type of point source data sheet is recommended. By identifying
emissions at the process level, the effect of various control strategies can
be better predicted.
Reference for Appendix B
1. Emission Inventory Requirements for 1982 Ozone State Implementation,
Plans, Draft, EPA-450/4-80-016, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1980.
B-l
-------
Principal Emitting Operations at Major
VOC Source Categories
Name and Location
Major VOC Source Category
Principal Operations
Emissions
Figure B-l. Point Source Process Emission Reporting Sheet,
B-2
-------
TABLE B-l.
INDIVIDUAL POINT SOURCE SUMMARY
STORAGE, TRANSPORTATION AND MARKETING OF VOC
Oil and Gas Production and Processing
Storage
Fugitives
Other Process Units (Specify)
Tank Farms
Fixed Roof Tanks
External Floating Roof Tanks
Primary Seals
Secondary Seals
Internal Floating Roof Tanks
Bulk Gasoline and VOC Terminals
Leaks from Valves, Flanges Meters, Pumps
Vapor Collection Losses
Vapor Control Unit Losses
Filling Losses from Uncontrolled Loading Racks
Tank Truck Vapor Leaks from Loading of Gasoline
Non-Tank Farm Storage
Gasoline Bulk Plants
Gasoline Bulk Storage
Loading and Unloading Racks (Controlled and Uncontrolled)
Tank Truck Vapor Leaks from Loading and Unloading of Gasoline
Leaks from Valves, Flanges, Meters, Pumps
Barge and Tanker Transfer
Gasoline Loading/Barge
Crude Oil Ballasting/Tanker
Barge and Tanker Cleaning
••
INDUSTRIAL PROCESSES
Petroleum Refineries
Process Drains and Wastewater Separators
Vacuum Producing Systems
Process Unit Turnarounds
Fugitive Leaks from Seals, Valves, Flanges
Pressure Relief Devices, Drains
Other Process Emissions Such as Heaters, Boilers,
Cat Cracker Regenerators (Specify)
Lube Oil Manufacture
B-3
-------
TABLE B-l (cont.). INDIVIDUAL POINT SOURCE SUMMARY.
Pharmaceutical Manufacture
Process Units Such as Vacuum Dryers, Reactors,
Distillation Units, Filters, Extractors,
Centrifuges, Crystallizers
Major Production Equipment Such as Exhaust Systems and
Air Driers
Storage and Transfer
Other Process Units (Specify)
Rubber Tire Manufacture
Undertread and Sidewall Cementing
Bead Dipping
Bead Swabbing
Tire Building
Tread End Cementing
Green Tire Spraying
Tire Curing
Solvent Mixing
Solvent Storage
Other Process Units (Specify)
Styrene Butadiene Rubber Manufacture
Slowdown Tanks
Steam Stripper
Prestorage Tanks
Other Process Units (Specify)
Vegetable Oil
Oil Extraction and Desolventization
Meal Preparation
Oil Refining
Fugitive Leaks
Solvent Storage
Other Process Units (Specify)
Organic Chemical Manufacture
Fugitive Leaks from Seals, Valves, Flanges,
Pressure Relief Devices, Drains
Air Oxidation Units
Waste Water Separators
Storage and Transfer
Other Process Units (Specify)
Polymer and Resin Manufacture
Catalyst Preparation
Reactor Vents
Separation of Reactants, Solvents and Diluents
from Product
Raw Material Storage
Solvent Storage
Other Process Units (Specify)
B-4
-------
TABLE B-l (cont.). INDIVIDUAL POINT SOURCE SUMMARY.
Plastic Parts Manufacture
Mold Release
Solvent Consumption
Adhesives Consumption
Other Process Units (Specify)
Inorganic Chemical Manufacture
Fugitive Leaks from Seals, Valves, Flanges,
Pressure Relief Devices, Drains
Storage and Transfer
Other Process Units (Specify)
Fermentation Processes
Fermentation Tank Venting
Ageing (Wine or Whiskey)
Other Process Units (Specify)
Iron and Steel Manufacture
Coke Production
Coke Pushing
Coke Oven Doors
Coke Byproduct Plant
Coke Charging
Coal Preheater
Topside Leaks
Quenching
Battery Stacks
Sintering
Electric Arc Furnaces
Other Process Units (Specify)
Synthetic Fiber Manufacture
Dope Preparation
Filtration
Fiber Extrusion - Solvent Recovery
Takeup Stretching, Washing, Drying, Crimping, Finishing
Fiber Storage - Residual Solvent Evaporation
Equipment Cleanup
Solvent Storage
Other Process Units (Specify)
INDUSTRIAL SURFACE COATING
Large Appliances
Cleaning and Pretreatment
Prime Spray, Flow, or Dip Coating Operations
Topcoat Spray
Coating Mixing
Coating and Solvent Storage
Equipment Cleanup
Other Process Emissions (Specify)
B-5
-------
TABLE B-l (cont.). INDIVIDUAL POINT SOURCE SUMMARY.
Magnet Wire
Cleaning and Pretreatment
Coating Application and Curing
Coating Mixing
Coating and Solvent Storage
Equipment Cleanup
Other Process Emissions (Specify)
Automobiles and Light Duty Trucks
Cleaning and Pretreatment
Prime Application, Electro deposition, Dip or Spray
Prime Surfacting Operations
Topcoat Operation
Repair Topcoat Application Area
Coating Mixing
Coating and Solvent Storage
Equipment Cleanup
Other Process Emissions (Specify)
Cans
Cleaning and Pretreatment
Two Piece and Exterior Base Coating
Interior Spray Coating
Sheet Basecoating (Interior)
Sheet Basecoating (Exterior)
Side Seam Spray Coating
End Sealing Compound
Lithography
Over Varnish
Coating Mixing
Coating and Solvent Storage
Equipment Cleanup
Other Process Emissions (Specify)
Paper
Coating Operations
Coating Mixing
Coating and Solvent Storage
Equipment Cleanup
Other Process Emission (Specify)
Coil Coating
Prime Coating
Finish Coating
Solvent Mixing
Solvent Storage
Equipment Cleanup
Other Process Emissions (Specify)
B-6
-------
TABLE B-l (cont.). INDIVIDUAL POINT SOURCE SUMMARY.
Fabric
Coating Operations
Coating Mixing
Coating and Solvent Storage
Equipment Cleanup
Other Process Emissions (Specify)
Wood Furniture
Coating Operations
Coating Mixing
Coating and Solvent Storage
Other Process Emissions (Specify)
Metal Furniture
Cleaning and Pretreatment
Coating Operations
Coating Mixing
Coating and Solvent Mixing
Equipment Cleanup
Other Process Emissions (Specify)
Flatwood Products
Filler
Sealer
Basecoat
Topcoat
Inks
Coating Mixing
Coating and Solvent Storage
Equipment Cleanup
Other Process Emissions (Specify)
Plastic Parts Painting
Cleaning and Pretreatment
Coating Operations, Flow, Dip, Spray
Coating Mixing
Coating and Solvent Storage
Equipment Cleanup
Other Process Emissions (Specify)
Large Ships
Cleaning and Pretreatment
Prime Coat Operation
Topcoat Operation
Coating Mixing
Coating and Solvent Storage
Equipment Cleanup
Other Process Emissions (Specify)
B-7
-------
TABLE Bl (cont.). INDIVIDUAL POINT SOURCE SUMMARY.
Large Aircraft
Cleaning and Pretreatment
Prime Coat Operation
Topcoat Operating
Coating and Solvent Storage
Equipment Cleanup
Other Process Emissions (Specify)
Miscellaneous Metal Parts and Products
Cleaning and Pretreatment
Coating Operations, Flow, Dip, Spray
Coating Mixing
Coating and Solvent Storage
Equipment Cleanup
Other Process Emissions (Specify)
OTHER SOLVENT USE
Dry Cleaning
Degreasing
Open Top Vapor Degreasing
Conveyorized Degreasing - Vapor
Conveyorized Degreasing - Cold Cleaning
Solvent Extraction Processes
Adhesives
Adhesive Application
Solvent Mixing
Solvent Storage
Other Process Emissions (Specify)
Graphic Arts
Letter Press
Rotogravure
Offset Lithography
Ink Mixing
Solvent Storage
OTHER SOURCES
Waste Solvent Recovery Processes
B-8
-------
APPENDIX C - SUMMARY OF CONTROL TECHNIQUES GUIDELINES
C-l BACKGROUND
The Clean Air Act Amendments of 1977 require each state having a non-
attainment area to adopt and submit a revised State Implementation Plan
(SIP) that meets the requirements of Section 110 and Subpart D of the Act.
The ozone plan portion of the SIP submissions must contain regulations which
reflect the application of reasonably available control technology (RACT) to
stationary sources for which control techniques guidelines (CTG) have been
published.*
Eleven CTGs, covering 15 VOC source categories, were published prior to
January 1978. These first eleven CTGs were:
0 Surface Coating of Cans, Coils, Paper, Fabric, Automobiles and
Light Duty Trucks (EPA-450/2-77-008).
0 Surface Coating of Metal Furniture (EPA-450/2-77-032).
0 Surface Coating for Insulation of Magnetic Wire
(EPA-450/2-77-033).
0 Surface Coating of Large Appliances (EPA-450/2-77-034).
0 Storage of Petroleum Liquids in Fixed Roof Tanks
(EPA-450/2-77-036).
0 Bulk Gasoline Plants (EPA-450/2-77-035).
0 Solvent Metal Cleaning (EPA-450/2-77-022).
Use of Cutback Asphalt (EPA-450/2-77-037).
0 Refinery Vacuum Producing Systems, Wastewater Separators and
Process Unit Turnarounds (EPA-450/2-77-025).
0 Hydrocarbons from Tank Gasoline Loading Terminals
(EPA-450/2-77-026).
0 Design Criteria for Stage I Vapor Control Systems, Gasoline
Service Stations, U.S. EPA, OAQPS, November 1975. Unpublished.
For each source category, a CTG describes the source, identifies the VOC
emission points, discusses the applicable control methods, analyzes the
costs required to implement the control methods, and recommends regulations
for limiting VOC emissions from the source.
RACT regulations do not have to be adopted for these stationary sources if
a state can demonstrate attainment of the ozone standard.
C-l
-------
A document entitled Regulatory Guidance for Control of Volatile Organic
Compound Emissions from 15 Categories of Stationary Sources, EPA-905/2-78-
001, was published in April 1978. This document provides guidance to the
states in preparing RACT regulations for the 15 source categories listed
above.
In December 1978, a document entitled Summary of Group I Control Tech-
nique Guideline Documents for Control of Volatile Organic Emissions from
Existing Stationary Sources, EPA-450/3-78-120, was published. This document
provides an overview of the affected source facilities, the magnitude of the
VOC emissions from the facilities, and the recommended VOC emission limits.
EPA published an additional 10 CTGs (Group II) in 1978. These 10
source categories covered were:
0 Leaks from Petroleum Refinery Equipment (EPA-450/2-78-036).
0 Surface Coating of Miscellaneous Metal Parts and Products
(EPA-450/2-78-015).
0 Manufacture of Vegetable Oil (EPA-450/2-78-035).
0 Surface Coating of Flat Wood Paneling (EPA-450/2-78-032).
0 Manufacture of Synthesized Pharmaceutical Products
(EPA-450/2-78-029).
0 Manufacture of Pneumatic Rubber Tires (EPA-450/2-78-030).
0 Graphic Arts - Rotogravure and Flexography (EPA-450/2-78-033).
0 Petroleum Liquid Storage in External Floating Roof Tanks
(EPA-450/2-78-047).
0 Perchloroethylene Dry Cleaning Systems (EPA-450/2-78-050).
0 Leaks from Gasoline Tank Trucks and Vapor Collection Systems
(EPA-450/2-78-051).
A regulatory guidance document was developed from these Group II CTGs.
Published in September 1979 and entiled Guidance to State and Local Agencies
in Preparing Regulations To Control Volatile Organic Compounds from Ten
Stationary Source Categories, EPA-450/2-79-004, this document provides
assistance to state and local agencies in preparing RACT regulations for the
10 industrial categories covered by the Group II CTG documents.
In June 1980, EPA began preparation of Control Techniques Guidelines
for additional source categories. Identified below are 12 categories for
which CTGs will be published in the latter part of 1981. This group will
most likely constitute the Group III CTG documents.
0 Volatile organic liquid loading into railcars
0 Fabric printing
0 Volatile organic liquid storage
0 Petroleum solvent dry cleaning
C-2
-------
Letterpress printing/offset lithography
0 Fugitive VOC, natural gas and natural gasoline
processing plants
0 Polymers and resins manufacturing
0 Fugitive VOC, synthetic organic chemical
manufacturing industry (SOCMI)
Air oxidation, synthetic organic chemical
manufacturing industry (SOCMI)
0 Styrene butadiene rubber manufacture
0 Waste solvent recovery processes3
0 Architectural surface coatings
nay be released later.
In August 1980, EPA began a VOC Source Screening Study. This study
will result in the publication of a single document summarizing emission
control technology for additional VOC source categories. The VOC source
categories listed below will be addressed in this study.
0 Adhesives application
0 Lubrication oil manufacture
0 Barge and tanker cleaning
0 Plastics parts painting
Oil and gas production storage tanks
0 Solvent extraction processes
0 Asphalt air blowing
0 Wine making
0 Beer making
Petroleum coking processes
0 Flares - petroleum refineries
0 Flares - organic chemical manufacture
° Surface coating - large ships
0 Surface coating - large aircraft
0 Surface coating - wood furniture
The source categories and publication schedules of the Group III CTGs
and the VOC Source Screening Study are tentative and subject to change. For
these reasons, agencies should contact EPA Regional offices for additional
information.
C-3
-------
C-2 GROUPS I & II CTG SUMMARIES
Summaries of Group I and II CTG documents are presented on this appendix
for the convience of the reader. These summaries have been extracted directly
from two documents developed by EPA's Control Programs Development Division
at Research Triangle Park, NC.^>2 The summaries are intended to present an
overview of the affected source facilities, the magnitude of the VOC emis-
sions from the facilities, and the recommended VOC emission limits. More
information about the recommended control techniques for an individual
source category can be obtained by referring to the specific CTG documents.
The regulatory guidance cited previously (EPA-450/2-79-004) discusses areas
of difficulty in.converting CTG information into regulatory language, a
compilation of industry comments on CTG information after conversion into
regulatory format, and identification of specific areas of industry concern.
For this executive summary, information not available in the CTGs was supple-
mented with comment from other parties.
References for Appendix C
1. Summary of Group I Control Technique Guideline Documents for Control of
Volatile Organic Emissions From Existing Stationary Sources,
EPA-450/3-78-120, U.S. Environmental Protection Agency, Research Triangle
Park, NC, December 1978.
2. Summary of Group II Control Technique Guideline Documents for Control
of Volatile Organic Emissions from Existing Stationary Sources,
EPA-450/2-80-001, U.S. Environmental Protection Agency, Research
Triangle Park, NC, December 1979.
C-4
-------
Table C-l.
SUNKARY OF CTG DOCUMENT FOR COATING OF CAr.'S
AFFECTLu
FACILITIES
NUMBER Or
AFFECTED
FACILITIES
VOC
EMISSIONS
NATIONWIDE
VOC
EMISSIO:,
RANGE
PER
FACILITY
TOO TON'/YR
SOURCE
SIZE
CTG
EMISSION
LIMIT
VOC
REDUCTION
PER
FACILITY
COSTS
Two- and three-piece can surface coatinc lines including the
application areas and the drying ovens.
Estimated to be 46C affected facilities nationwide.
Estimated annual emissions from can coating facilities are 14r,c^
Mg/yr (150,000 ton/yr) which represent about 0.5 oercer.t of the estiVits.-!
nationwide VQf erissio^s.
Typical annual emissions fror can coatinq lines car, v?.r> fror 13 Xc
(U tons) for end sealing to 2^C Kg (260 ton) for two-piece car. coat-
ing for a plant average of 310 Kg (340 ton).
Typical can coating facilities as represented in the CTG would all
approach or exceed 100 TPY VOC emissions if uncontrolled.
The recommended VOC emission limits are:
a. Sheet coating, two-piece exterior 0.34 kg/1 (2.8 lb/gal)*
b. Two- and three-piece interior 0.51 kg/1 (4.2 lb/gal)*
c. Two-piece end exterior 0.51 kg/1 (4.2 lb/gal)*
d. Three-piece side seam 0.66 kg/1 (5.5 lb/gal)*
e. End seal compound 0.44 kg/1 (3.7 Ib/gal)*
The actual percent reduction will vary depending on the solvent
content of the existing coatings and the control method selected.
Implementation of the recommended control methods can reduce VOC eris-
sions by 60 to 100 percent.
BASIS: 5,000 scfm facility using thermal or catalytic incinera-
tion with primary heat recovery, or adsorption with recovered solvent
credited at fuel value.
CAPITAL COST: $125,000 - $162,000
ANN'UALIZED COST: $42.000 - $71,000
COST EFFECTIVENESS: $135 - $706 per ton VOC
Coating minus water
C-5
-------
Table C-2.
SUMMARY OF CTG DOCUMENT FOF COATING OF ME7A. COILS
AFFECTED I Coil surface coating lines including the application areas, tnt
FACILITIES ! ing ovens, ana the quench areas.
NU'IEEF OF
AFFECTED
FACILITIES
Estimated to be 180 facilities nationwide.
VOC
EMISSIONS
Estimated annual emissions frorr. coil coating facilities are 3^,OC..
K;/yr (33.0DC torYvr), which represent about 0.1 cercent of tr^ esn-
NATIONWJDE I mated nationwide VOC emissions.
vo:
EMISSION
RAN3E PER
FACILITY
Averaqe annual VOC emission for a typical facility is estimated
to be 180 Kg (200 ton) .
...
100 TON/YR
SOURCE
SIZE
result in a potential emission of 100 tons of VOC.
It is estimated that 2 x 106ir2 (2 x 1C9 ft2) of ceil coatee ccJc
CTG
EMISSION
LIMIT
The reconroended VOC emission limit is 0.31 kg per liter of coating
minus water (2.6 Ib/gal}.
VOC
REDUCTION
PER
FACILITY
The actual percent reduction will vary depending on the solvent
content of the existing coatings and the control method selected. Imple-
mentation of the recommended control methods can reduce VOC emissions by
70 to 98 percent.
COSTS
BASIS: 15,000 scfm facility using incineration witr, primary heat
recovery.
Capital cost: ~ $170,000
Annualized cost:
Cost effectiveness:
$ 70,oo:
$51 - $94 per ton VOC
C-6
-------
Table C-3.
SUNDRY OF CT& DOCUMENT FOR COATING OF FABRIC AND VINYL
AFFECTED
FACILITIES
NUMBER OF
AFFECTED
FACILITIES
VOC
EMISSION'S
NATIONWIDE
VOC
EMISSION
RANGE PER
FACILITY
100 TON/YR
SOURCE
SIZE
CTG
EMISSION
LIMIT
VOC
REDUCTION
PER
FACILITY
COSTS
Fabric and vinyl surface coating lines including the application
areas and the drying ovens. Fabric coating includes a1! types cf
coatings applied to fabric. Vin_\l coating refers to any printing.
decorative, or protective topcoat applied over vinyl coated faoric or
vinyl sheets.
Estimated to be 130 facilities nationwide.
i
Estimated annjal emission fror fabric coating operations are IGT.CTr ;
Mc/yr (110,000 tor./vr). The vinyl seanert of the fabric ir.a.itrj
e,-:ts about 36, OX Kg/yr (40,000 ton/yr). VOC fror fabric coetir,: rep-
resents about C.£ percent of the estimated VOC em'ssions nation- idt .
Average annual VOC emissions are estimated to be 850 Me (943 tor,).
1
Any but the smallest fabric coating facilities should exceed emis-
sions of 100 ton/yr of VOC.
The recommended VOC emission limits are:
a. Fabric coatina 0.35 kg per liter of coating minus water
(2.9 lb/gal)."
b. Vinyl coating 0.45 kg per liter of coating minus water
(3.8 Ib/gal).
The actual percent reduction will vary depending on the solvent
content of the existing coatings and the control method selectea.
Implementation of the recommended control methods can reduce VOC emis-
sions by 80 to 100 percent.
BASIS: 15,000 scfrr facility using incineration nith prir,ar> heat
recovery or adsorption with recovered solvent credited at fuel velje
Capital cost: $150,000 - $320,000
Annualized cost: $ 60,000 - $ 75,000
Cost effectiveness: $34 - $39 oer tor. vn:
C-7
-------
Table C-4.
SUMMARY OF CTG DOCUMENT FOR SURFACE COATING OF PAPER PRODUCTS
ATECTED
FACILITIES
NUMEEP OF
AFFECTED
FACILITIES
VOC
EMISSION'S
NVTIOU'IDE
VOC
EMISSION
RANGE PER
FACILITY
IOC TON/YR
SOURCE
SIZE
CTG
EMISSION
LIMIT
VOC
REDUCTION
PER
FACILITY
COSTS
Haper surface coating lines including the application areas ar.j u.t '.
drying ovens. The CTG document applies to manufacturing cf adhesive !
tapes, adhesive labels, decorated paper, book covers, office copier i
paper, carbon paper, typewriter ribbons, and photographic films. j
SIC 2641, Paper Coating and Glazing, had 397 plants in 1967. j
Current estimates for this category are 290 plants nationwide
Estimated annual emissions are 320,000 Mg/yr (350,03: tor yr) 0-
this amount, the manufacture of pressure sensitive tapes an; labels u.
estimated to erit 263,000 K;'yr (290,000 tor/yr). Erissior; fror tr .
coating of Paper products represent about 1.2 percent of nationwide VO:
emissions.
Emissions from typical paper coating lines can vary fror 23 tc
450 kg/hr (SO to 1,000 Ib/hr). A plant may have 1 to 20 coating lines.
It is estimated that the annual average VOC emission from paper coating
plants is 1,480 Mg (1,630 ton).
Based on the data given, a plant with one large line or two
small lines can exceed 100 ton/yr of VOC emissions.
The recommended VOC emission limit is 0.35 kg per liter
of coating minus water (2.9 Ib/gal).
The actual percent reduction will vary depending or, the sclver.t
content of the existing coatings and the control method selected.
Implementation of the recommended control methods can reduce VOO
emissions by 80 to 99 percent.
BASIS: 15,000 scfir, facility using incineration with primary heat
recovery or adsorption with recovered solvent credited at fuel falu-.
Capital cost: $150,000 - S32C.OOC
Annualized cost: $ 60,000 - $ 75,000
Cost effectiveness: $34 - $40 per ton VOC
C-8
------- An error occurred while trying to OCR this image.
-------
Table C-6.
SUMMARY OF CTG DOCUMENT FOR COATING OF METAL FURNITURE
AFFECTED
FACILITIES
NUMiER OF
AFFECTED
FACILITIES
VOC
EMISSIONS
NATIONWIDE
VOC
EMISSION
RANGE PER
FACILITY
TOO TON/YR
SOURCE
SIZE
CTG
EMISSION
LIMIT
VOC
REDUCTION
PER
FACILITY
COSTS
Metal furniture surface coating lines including the
application and flashoff areas, and the drying ovens.
Approximately 1,400 facilities would be affected naticr.a'ly.
Estimated annual emissions are 90,000 Mg/yr (IOC, 00? tor,'
yr). This represents about 0.3 percent of estimated VOC
emissions nationwide.
Estimated average annual VOC emissions are 70 Mg
(80 ton) per facility.
i
For a model dip coating line, a plant coating (with nc primer),
7 2
1,500,000 m (16,200,000 ft ) of shelving per year would etr.it
about 100 ton/yr.
The recommended VOC emission limit is 0.36 kg per liter
of coating minus water (3.0 Ib/gal).
The actual percent reduction will vary depending on the solvent
content of the existing coatings and the control method selected.
Implementation of the recommended control methods can reduce VOC
emissions by 50 to 99 percent.
BASIS: A dip coating facility coating 7,OOD,OOC ft2 of she u u.;
per year converting to water-borne or electrodeposition:
Capital cost: $ 3,000 - $124,000
Annual ized cost: $11,000 - $ 25,003
Cost effectiveness: $440 - $657 per ton VOC
C-10
-------
Table C-7.
SUMMARY OF CTG DOCUMENT FOR COATING OF MAGNET WIRE
AFFECTED
FACILITIES
NUMBER OF
AFFECTED
FACILITIES
VOC
EMISSIONS
NATIONWIDE
VOC
EMISSION
RANGE PER
FACILITY
100 TON/YR
SOURCE
SIZE
CTG
EMISSION
LIMIT
VOC
REDUCTION
PER
FACILITY
COSTS
Wire coating oven.
Estimated to be 30 plants nationwide. It is not unusual for a *irt
coating plant to have 50 coating ovens.
CTG states that there is no way to know how much solvent is actual! > !
emitted. About 29,500 metric tons (32,500 ton) of solvent are used ecc1".
year but much of this is controlled.
Emissions from a typical uncontrolled oven will be approximately Ve.
kg/hr (26 Ib/hr). The average annual emissions of VOC per plant are
estimated to be 314 Mg (34C ton)
CTG indicates that each of the facilities, if uncontrolled, could
easily exceed 100 1
The recommended VOC emission limit is 0.20 kg per liter of coating
minus water (1.7 lb/gal).
The actual percent reduction will vary depending on the solvent
content of the existing coatings and the control method selected.
Implementation of the recommended control methods can reduce VOC
emissions by 90 percent.
BASIS: 10,000 scfm facility controlling VOC by use of incineration
with primary heat recovery.
Capital cost: Approximately $220,000
Annualized cost: $85,000 - $115,000
Cost effectiveness: $105 - $140 per ton VOC
C-ll
-------
Table C-8.
SUMMARY OF CTG DOCUMENT FOR COATING OF LARGE APPLIANCES
AFFECTED
FACILITIES
NUKEER OF
AFFECTED
FACILITIES
VOC
EMISSIONS
NATIONWIDE
VOC
EKISSIO'.
RANGE PER
FACILITY
IOC TON/YR
SOURCE
SIZE
CTG
EMISSION
LIMIT
VOC
REDUCTION
PER
FACILITY
COSTS*
Large appliance surface coating including the prime, single, or
topcoat application areas, the flashoff areas, and the oven.
Estimated to be about 270 plants nationwide.
Estimated annual eir.issions are 42.00C Mg/yr (4£,000 ton/yr)
which represent about 0.2 percent of estimated nationwide VOC
eirissions.
The average annual VOC eirissions are estimated to be
170 Mg (185 ton).
Extrapolating the model facility data, a plant coating 221,03:
clothes washer cabinets per year would exceed 100 ton/yr emissions of
uncontrolled VOC.
The recommended VOC emission limit is 0.34 kg per liter
of coating minus water (2.8 Ib/gal).
The actual percent reduction will vary depending on the solvent
content of the existing coatings and the control method selected.
Implementation of the recommended control methods can reduce VOC
emissions by 79 to 95 percent.
BASIS: 768,000 clothes washer cabinets coated per year using
various combinations of control techniques.
Capital cost: $70,000 - $1,250,000
Annualized cost: ($300,000) - $350,000
Cost effectiveness: ($1.050) - $1,180 per ton VOC
* ($-—) indicates savings
C-12
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Table C-9.
SUMMARY OF CTG DOCUMENT FOR TANK TRUCK GASOLINE LOADING TERMINALS
AFFECTED
FACILITIES
NUMBER OF
AFFECTED
FACILITIES
VOC
EMISSIONS
NATIONWIDE
VOC
EMISSION
RANGE PER
FACILITY
TOO TON/YR
SOURCE
SIZE
CTG
EMISSION
LIMIT
VOC
REDUCTION
PER
FACILITY
COSTS
Any tank truck loading operations at the primary wholesale outlet
for gasoline which delivers at least 76,000 liter/day (20.000 gal/da/'!.
A facility which delivers under 20,000 gal/da^ is coverec t> the
CTG for bulk plants.
According to the Bureau of Census, there were 1,925 temr.als in
1972. Current estimates are about 1,600 terminals nationwide
Estimated annual emissions are 250,000 Mg/yr (275,000 ton yr)
wnich represent about 0.9 percent of estimated VOC emissions nationwide
Without vapo1- recovery systems, VOC emissions car range frcr 0.6 tc
1.4 g/1,000 liters of throughput (5 to 12 lb/1,000 gal). For a tyficel
size facility having a throughput of 950,000 liter/day (250,032 cal'ja;. )
VOC emissions are estimated to be 200 Mg/yr (220 tor,/yr).
For an uncontrolled facility with fixed roof tanks, a 133,000 liter
/day (35,000 gal/day) plant would result in VOC emission of 10: tor 'yr .
For an uncontrolled facility with floating roof tanks, a 454,000 liter/
day (120,000 gal/day) facility would result in VOC emissions of
100 ton/yr.
The recommended emission limit is 80 mg/liter (0.67 lb/1,000 gal)
of gasoline loaded. This limit is based on submerged fill and vapor
recovery/control systems. No leaks in the vapor collection syste.T.
during operation is a requirement.
A minimum control of 87 percent is expected for the loading
facility.
BASIS: 250,000 gal/day facility with active vapor control systems.
Capital cost: $140,000 - $195,000
Annualized cost: $ 20,000 - $ 30,000
Cost effectiveness: $120 - $180 per ton VOC
C-13
-------
Table C-10.
SUMMARY OF CTG DOCUMENT FOR BULK GASOLINE PLANTS
AFFECTED
FACILITIES
NUMBER OF
AFFECTED
FACILITIES
VOC
EMISSIONS
NATIONWIDE
VOC
EMISSION
RANGE
PER
FACILITY
TOO TON/YR
SOURCE
SIZE
CTG
EMISSION
LIMIT
VOC
REDUCTION
PER
FACILITY
COSTS
A wholesale gasoline distribution facilm wMcr, hz3 a r.axir..^;, '
daily througnput of 76,000 liters (20,000 gal) of gasoline.
Facilities which deliver over 20.000 gal/day are covered under
the CTG for terminals. Potentially severe economc hardsri; mav De
encountered by bulk plants which deliver less than 4,000 gal'de>.
There were 23,367 bulk plants in 1972 according to the
Bureau of Census. Current estimates are about 18,000 bulk
gasoline plants nationwide.
Estimated annual emissions are 150,000 Mg/yr (165,00: tor,/yr ,
which represent about 0.6 percent of estimated VOC
emissions nationwide.
A facility with three storage tanks would have VOC emissions
approximating 4.4 kg/day (2C Ib/day) plus a range of 0.2 to 3.0 c. '
1,000 liters throughput (2.C tc 25.0 lb/1,000 gel). For a t>;ical
size facility having a throughput of 18,900 liter/day (5,000 qal/
day) average VOC emissions are estimated to be 15 Mg/yr (17 tor, 'yr', .
None.
Emission limits recommended in terms of equipment specification
alternatives:
1. Submerged fill of outgoing tank trucks.
2. Alternative 1 •+ vapor balance for incoming transff .
3. Alternative 2 + vapor balance for outgoing transfer.
Emission Reductions Total Plant All Transfers,
Alternative 1 22 percent 27 percent
Alternative 2 54 percent 64 percer.t
Alternative 3 77 percent 92 percent
BASIS: 4,000 gal /day throughput using submerged fill
and vapor balance for both incoming and outgoing transfers.
Capital cost: $4,000 - $10,000
Annual ized cost: $ IOC - $ 1,200
Cost effectiveness: $9 - $90 per ton VOC
C-14
-------
Table C-ll.
SUMMARY OF DOCUMENT FOR GASOLINE SERVICE STATIONS - STAGE I
AFFECTED
FACILITIES
DUMBER OF
AFFECTED
FACILITIES
voc
EMISSIONS
NATIONWIDE
VOC
EMISSION
RANGE PER
FACILITY
100 TON/YR
SOURCE
SIZE
CTG
EMISSION
LIMIT
VOC
REDUCTION
PER
FACILITY
COSTS*
Transfer of gasoline from delivery trucks to service station
storage tanks.
No exemptions were noted in the "Design Criteria for Staoe I
Vapor Control Systems."
Estimated to be 180,000 retail gasoline service stations
nationwide. There are 240,000 other gasoline dispensing outlets.
For transfer of gasoline to service station storage tanks, VOC
emissions estimated to be 400,000 Mg/yr (440, OOC ton/yr)
which represents about 1.5 percent of estimated VOC emissions
nationwide.
Without vapor controls, VOC emissions are estimated to be
1.4 kg/1,000 liters (11.5 lb/1,000 gal) of throughput. For a typical
facility having a throughput of 151,000 liter/mo (40,000 gal/mo) VOC
emissions would be 2.5 Mg/yr (2.8 ton/yr) for Stage I.
For an uncontrolled facility, a 2,800,000 liter/mo (750,000
gal/mo) throughput results in VOC emissions of 100 ton/yr. Very
few service stations will have this size throughput. The emissions
Include both Stage I and Stage II losses.
Emission limits recoranended in terms of equipment specifications.
Recommended controls are submerged fill of storage tanks, vapor balance
between truck and tank, and a leak free truck and vapor transfer systen..
Stage I control can reduce transfer losses by 95+ percent and
total facility losses by 50 percent.
BASIS: Application of submerged fill and vapor balance to a
service station with three tanks.
Capital cost: $600
Annualized cost: ($200)
Cost effectiveness: ($110) per ton VOC
* ($—) indicates savings
C-15
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Table C-13.
SUMMARY OF CTG DOCUMENT FOR PROCESSES AT PETROLEUM REFINERIES
AFFECTED
FACILITIES
The affected facilities and operations are:
a. Vacuum producing systems (VPS)
b. Wastewater separators (WS)
c. Process unit turnarounds (PUT) - (i.e., shutdown, repair
or inspection, and start up of a process unit)
The CTG provides no exemptions.
NUMBER OF
AFFECTED
FACILITIES
No estimates of the number of individual facilities are
available. There are approximately 285 refineries nationwide.
VOC
EMISSIONS
NATIONWIDE
Estimated annual nationwide emissions from vacuum producing systems
(VPS), wastewater separators (WS), and process unit turnarounds (PUT)
are 730,000 Mg/yr (800,000 ton/yr) which represent about 2.7 percent
of estimated VOC emissions nationwide.
VOC
EMISSION
RANGE
PER
FACILITY
The estimated average annual VOC emissions from affected facilities
at a petroleum refinery are 2,560 Mg (2,820 ton). Emission factors used
for estimating uncontrolled, reactive VOC emissions are:
a. VPS - 145 kg/10
b. WS - 570 kg/10>:r
c. PUT - 860 kg/loV
( 50 Ib/iof bbl) refinery throughput
(200 lb/10, bbl) refinery throughput
(301 lb/10J bbl) refinery throughput
100 TON/YR
SOURCE
SIZE
The following annual refinery throughputs will result in 100 ton/yr
uncontrolled VOC emissions from each affected facility type:
a. VPS - 627 x 10.2m3.
b. WS - 160 x 10X
c. PUT - 105 x 10V
(3.9
(1.0
x 10° bbl)
x 10" bbl)
(0.67 x 10° bbl)
CTG
EMISSION
LIMIT
Emission limits recommended in terms of equipment specifications
a. VPS - incineration of VOC emissions from condensers
b. WS - covering separator forebays
c. PUT - combustion of vapor vented from vessels
VOC
REDUCTION
PER
FACILITY
Implementing the recommended controls can reduce VOC emissions bj<:
a. VPS - 100 percent
b. WS - 95 percent
c. PUT - 98 percent.
COSTS*
BASIS: A 15,900 m /day (100,000 bbl/day) refinery using the
recommended control equipment.
VPS W S PUT - 10 units
Capital cost $1,000: 24 - 52 63 98
Annualized cost $1,000: ( 95) - (89) (310) 26
Cost effectiveness $/ton : (104) - (96) ( 90) 5
* ($-) indicates savings
C-17
-------
Table C-14.
SUMMARY OF CTG DOCUMENT FOR CUTBACK ASPHALT
AFFECTED
FACILITIES
NUMBER OF
AFFECTED
FACILITIES
VOC
EMISSIONS
NATIONWIDE
VOC EMISSION
RANGE PER
FACILITY
100 TON/YR
SOURCE SIZE
CTG
EMISSION
LIMIT
VOC
REDUCTION
PER
FACILITY
COSTS*
Roadway construction and maintenance operations using asphalt liaj^fici
with petroleum distillates.
No estimates were obtained.
Estimated annual emissions are 655,000 Mg/yr (720,000 ton/yr). This
represents about 2.4 percent of estimated VOC emissions nationwide.
Estimated VOC emissions from cutback asphalt production are:
a. 0.076 kg/kg (ton/ton) of slow cure asphalt.
b. 0.209 kg/kg (ton/ton) of medium cure asphalt.
c. 0.204 kg/kg (ton/ton) of rapid cure asphalt.
Not generally applicable to this source category since the main sources
of emissions are the road surfaces where the asphalt is applied.
Substitute water and nonvolatile enulslfier for petroleum distillate
blending stock.
VOC emission reductions are approximately 100 percent.
BASIS: The major cost associated with control of VOC is the price
difference between cutback and emulsified asphalt. A price differential
of 5 cent/gallon savings to 1 cent/gallon penalty results in a cost ef-
fectiveness range of ($73) - $15 per ton VOC.
* ($---) indicates savings
C-18
-------
Table C-15.
SUMMARY OF CTG DOCUMENT FOR SOLVENT METAL CLEANING
AFFECTED
FACILITIES
Three types of solvent degreasers are affected:
a. Cold cleaner: batch loaded, nonbeiling solvent dec'-easer.
b. Open top vapor degreaser: batch load, boiling solvent
degreaser.
c. Conveyorized degreaser: continuously loaded, conveyorized
solvent degreaser, either boiling or nonboiling.
2
Open top vapor degreasers smaller than 1 m of open area are exeir.pt
from the application of refrigerated chillers or carbon adsorbers.
Conveyorized degreasers smaller than 2.0 m' of air/vapor interface
are exempt from a requirement for a major control device.
NUMBER OF
AFFECTED
FACILITIES
Estimates of the number of solvent degreasers nationwide for the
year 1974 are:
a. Cold cleaners (CC) - 1,220,000.
b. Open top vapor degreasers (OT) - 21,000.
c. Conveyorized degreasers (CD) - 3,700.
VOC
EMISSIONS
NATIONWIDE
Estimates of annual nationwide emissions are:
a. CC - 380,000 Mg/yr (419,000 ton/yr).
b. OT - 200,000 Mg/yr (221,000 ton/yr)
C. CD - 100,000 Mg/yr (110,000 ton/yr)
which represent about 2.5 percent of estimated VOC emissions nationwide.
VOC
EMISSION
RANGE PER
FACILITY
Averaged emission rates per degreaser:
a. CC - 0.3 Mg/yr (0.3 ton/yr).
b. OT - 10 Mg/yr (11 ton/yr).
c. CD - 27 Mg/yr (30 ton/yr).
100 TON/YR
SOURCE
SIZE
Data indicate that on an average 10 open top degreasers or 4 con-
veyorized degreasers may emit 100 ton/yr.
CTG
EMISSION
LIMIT
The VOC emission limit is recommended in terms of equipment speci-
fications and operation procedures. Required control equipment can be
as simple as a manually operated tank cover or as complex as a carbor,
adsorption system depending on the type, size, and design of the
degreaser.
VOC
REDUCTION
PER
FACILITY
The actual percent VOC reduction will vary depending on the control
equipment installed and the operational procedures followed. Recommend-
ed control methods can reduce VOC emissions by:
a. CC - 50 to 53 percent (+ 20 percent).
b. OT - 45 to 60 percent (+ 15 percent).
c. CD - 25 to 60 percent (+ 10 percent).
BASIS: CC of 0.5 m work area using high volatility solvent (a)
and low volatility solvent (b); OT of 1.67 m? work area; and CD of
COSTS *
CC-a
fcb
CD
Capital Cost
51,000
0.025
0.065
0.3 - 10.3
7.5 - 18
Annual ized Cost
$1.000
.0.001
(0.026)
(0.8) - 0.8
3.7 - 1.5
* ($---} indicates savings
Cost Effectiveness
$/ton VOC
20
(240)
(360) - 220
(260) - 260
C-19
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Table C-18.
SUMMARY OF CTG DOCUMENT FOR MANUFACTURE OF SYNTHESIZED
PHARMACEUTICAL PRODUCTS
Affected
facilities
(p. 1-4)*
Number of
affected
facilities
(p. 1-2)*
VOC
amis B ions
nationwide
VOC
emission
range per
facility
100 ton/yr
source size
CTG
•mission
limit
(p. 1-5)*
VOC
reduction
p«r facility
Costs
(pp. 5-14
to 5-42)*
Synthesized pharmaceutical manufacturing facilities. Specific
sources include:
1. Dryers 5. Filters
2. Reactors 6. Extraction equipment
3. Distillation Units 7. Centrifuges
4. Storage and transfer 8. Crystallizers.
of VOC
Estimated 800 plants nationwide
50,000 Mg/yr (55,000 tons/yr) estimated for 1977 which represents
about 0.3 percent of stationary source estimated VOC emissions.
Not available
Not available
1. a. Surface condensers or equivalent control on vents from
reactors, distillation operations, crystallizers, cen-
trifuges, and vacuum dryers that emit 6.8 kg/ day (15 Ib/day)
or more VOC.
b. Surface condensers must meet certain temperature versus VOC
vapor pressure criteria.
2. Additional specific emission reductions are required for air
dryers, production equipment exhaust systems, and storage and
transfer of VOC.
3. Enclosures or covers are recommended for rotary vacuum filters,
processing liquid containing VOC and in-process tanks.
4. Repair of components leaking liquids containing VOC.
Not available
Capital and Annualized Cost graphs are provided for the following types
of control equipment: conservation vents, floating roofs, pressure
vessels, carbon adsorption systems, thermal and catalytic incineration
systems, water cooled condensers, chilled water and brine cooled con-
densers, freon cooled condensers, packed bed scrubbers and venturi
scrubbers. •.*•!.*
Cost effectiveness data is not calculated for typical plants.
TT 1"formation ls the indicated page(s) in "Control of Volatile
Manufacture of Synthesized Pharmaceutical Products,"
C-22
-------
Table C-19.
SUMMARY OF CTG DOCUMENT FOR MANUFACTURE OF PNEUMATIC RUBBER TIRES
Affected
facilities
(pp. 1-1,
1-3)*
Rubber tire manufacturing plants, producing passenger car, and light
and medium duty truck tires. Operations affected are: undertread
cementing, bead dipping, tread end cementing, and green tire spraying.
Number of
affected
facilities
(p. 2-2)*
Maximum of 62 rubber tire plants nationwide
VOC
emissions
nationwide
(p. 1-2)*
1976 VOC emissions estimate from rubber tire manufacturing totalled
88,200 Mg/yr (97,200 tons/yr). This quantity represents 0.6 percent
of total national VOC emissions from stationary sources.
VOC
emission
range per
facility
(p. 1-2)*
The average tire plant is estimated to release 4,000 kg per day
(8,820 Ib/day) of emissions or 1,000 Mg VOC per year (1,100 tons/yr),
100 tons/yr
source size
(p. 2-8) *
The model plant, producing 16,000 tires/day, has potential to emit
1,460 Mg/yr (1,600 tons VOC/yr). Therefore a plant producing approxi-
mately 1,000 tires/day would be a potential 100 tons/yr source.
CTG
emission
limit
(p. 4-2) *
VOC emissions reduction from the affected operations is recommended
through use of carbon adsorption or incineration. Water-based coat-
ings may be used for green tire spraying.
VOC
reduction
per facility
(p. 1-4) *
a. Carbon adsorption gives an overall efficiency of 62-86 percent in
reducing VOC emissions, when applied to the affected operations.
b. Incineration gives an overall efficiency of 59-81 percent when
applied to the affected operations.
c. Water-based coatings, applied to green tire spraying, provide an
overall emission reduction efficiency of 97 percent.
Costs
(pp. 4-11,
4-15) *
Basis; A model 16,000 tires/day plant using the various control
technologies recommended on the following affected operations.
All costs are based on January 1978 dollars.
Capital cost
($1000)
Annual!zed cost
($1000)
Cost effectiveness
($/Mg)
($/ton)
Undertread
cementing
130-340
92-280
166-505
150-458
Bead dipping
115-250
70-985
1,400-20,800
1,340-18,800
Tread end
cementing
135-375
100-340
1,140-3,880
1,000-3,500
Green tire
spraying
15-450
118-490
202-839
184-763
*The source of the summary information is the indicated page(s) in "Control
of Volatile Organic Emissions from Manufacture of Pneumatic Rubber Tires "
EPA-450/2-78-030.
C-23
-------
Table C-20.
SUMMARY OF CTG DOCUMENT FOR GRAPHIC ARTS - ROTOGRAVURE
AND FLEXOGRAPHY
Affected
facilities
(p. l-D*
Nuntoer of
affected
facilities
(p. 2-5)*
voc
emissions
nationwide
(p. 2-8)*
VOC
e ml SB Ion
range per
facility
(calculated)
100 tons/yr
source size
L__
CTG
emission
limit
(pp. 1-2,
1-3) *
VOC
reduction
per facility
Costs
(pp. 4-8
4-13) *
Flexographlc and rotogravure processes applied to publication ,uu j
packaging printing.
- . - -
a. Publication printing is done in large printing plants, mimbe
^SB than 50 in total.
riiif.
b. There are approximately 13 to 14 thousand gravure printing units
and 30 thousand flexographic printing units.
Q. Gravure 100,000 Mg/yr 1976 (110,000 tons/yr)
'b. Flexography 30,000 Mg/yr 1976 (33,000 tons/yr)
This represents about 0.8 percent of stationary source estimated
emissions.
. .
a. Gravure 7.4 Mg/printing unit per year |
(8.2 tons/unit)
b. Flexography 1 Mg/printing unit per year
(1.1 tons/printing unit per year)
A plant will be a potential 100 tons/yr VOC source if it uses
110-180 Mg (120-200 tons) of ink per year, where the solvent
concentration is 50-85 percent.
Use of water-borne or high solids inks meeting certain composition
criteria or the use of capture and control equipment which provides:
a. 75 percent overall VOC reduction where a publication
rotogravure process is employed;
b. 65 percent overall VOC reduction where a packaging roto-
rotof.ravure process is employed; or,
c. 60 percent overall VOC reduction where a flexographic
printing process is employed.
Same as CTG limit above.
VOC control option
Ink usage,
Mg/yr
(tons/yr)
VOC concentration ppm
Capital cost
Annuallzed cost
Cost effectiveness)
S/Mu
$/ton
Incinerator
7
(7.7)
500
94,000
24,900
8,360
7,570
Incinerator
2,500
(2,750)
500
1,110,000
1,665,500
1,650
1,480
Carbon
adsorption
3,500
(3,860)
i 1,200
701,000
72,800
51
46
__
Carbon
adsorption
7 ,000
(7,720)
2,400
7(U ,000
(41,700)t
(15)1
( i D-I
*The source of the summary information is the indicated page number in "Control of
Volatile Organic Emissions from Existing Stationary Sources, Volume VIII: Graphic
Arts - Rotogravure and Flexography," EPA-450/2-78-033.
1 Hunters in parentheses are savings.
C-24
-------
Table C-21.
SUMMARY OF CTG DOCUMENT FOR PERCHLOROETHYLENE DRY CLEANING SYSTEMS
Affected
facilities
(p. 2-1)*
Number of
affected
facilities
(calculated)
VOC
emissions
nationwide
(pp. 1-2,
2-1) *
VOC
emission
range per
facility
(p. 5-2)*
100 tons/yr
source size
(extrapolated)
CTG
emission
limit
(pp. 6-1 -
6-4)*
VOC
reduction
per facility
(pp. 2-5,
2-7)*
Coats
(p. 4-5)*
Affected facilities are coin-operated, commercial, and industrial dry
cleaning systems which utilize perch loroethy lene as solvent.
a. Coin-op 14,900
b. Commercial 44,600
c. Industrial 230
a. Coin-op 21,400 Mg/yr (23,500 tons/yr)
b. Commercial 123,000 Mg/yr (135,000 tons/yr)
c. Industrial 13,600 Mg/yr (15,000 tons/yr)
The estimated 158,000 Mg VOC/yr is 0.9 percent of total stationary
source estimated emissions.
Uncontrolled VOC emissions
Type of plant kg/yr (Ib/vr)
a. Coin-op 1,460 (3,200)
b. Commercial 3,240 (7,200)
c. Industrial 32,400 (72,000)
A large industrial dry cleaning plant, processing 750 Mg (825 tons)
clothes per year, would be a potential 100 tons VOC per year source.
of
a. Reduction of dryer outlet concentration to less than 100 ppm VOC,
by means of carbon adsorption. (Facilities with inadequate space •
or steam capacity for adsorbers are excluded.)
b. Reduction of VOC emissions from filter and distillation wastes.
c. Eliminate liquid and vapor leaks.
Carbon adsorption applied to commercial and industrial plants will
reduce overall VOC emissions by 40-75 percent.
Basis: Carbon adsorbers for a commercial plant- rloqning 46 000 kg
(100,000 Ib) of clothes per year. " ° •-,--- -e
Capital cost $4,500
Annualized cost $300
Cost effectiveness $90 credit/Mg
$80 credit/ton
*The source of the summary information is the indicated page number in "Control of
Volatile Organic Emissions from Perchloroethylene Dry Cleaning Systems," EPA-450/2-78-050,
C-25
-------
Table C-22.
SUMMARY OF CTG DOCUMENT FOR LEAKS FROM PETROLEUM REFINERY EQUIPMENT
Affected
facilities
(p. 6-])*
Petroleum refinery equipment including pump seals, compressor
seals, seal oil degassing vents, pipeline valves, flanges and
other connections, pressure relief devices, process drains,
and open ended pipes.
Number of
affected
facilities
There were 311 petroleum refineries in the nation as of
January 1, 1979.
VOC
emissions
nationwide
(p. 5-1)*
The estimated VOC emissions nationwide are 170,000 Mg/year,
or about 1 percent of the total VOC emissions from stationary
sources.
VOC
emissions
range per
facility
(p. 3-2)*
The potential VOC emissions per leaking source range from 1.0 to
10 kg/day.
100 ton/year
source size
(p. 3-3, 2-3)*
A single leaking source has the potential to emit 0.4 to 3.7 Mg
VOC/year (0.5 to 4.1 ton/yr). A refinery with between 25 and
227 leaking components would emit 100 tons/year of VOC. A
model medium size refinery may have 90,000 leaking components.
CTG
emission
limits
(p. 1-3)*
If a leaking component has a VOC concentration of over 10,000 ppm
at the potential leak source, it should be scheduled for main-
tenance and repaired within 15 days.
VOC
reduction per
facility
(calculated)
Estimated to prevent the release of 1821.1 Mg/year (2007.4 ton/
year) of VOC at a model medium size refinery (15,900 m3/day) by
reducing emissions from 2933.6 Mg (3233.5 ton) to 1112.5 Mg
(1226.1 ton) per year
Costs
(p. 4-8)*
Basis: A monitoring and maintenance program for a 15,900 m /day
(100,000 bbl/day) refinery (Fourth quarter 1977 dollars).
Instrumentation Capital Cost 8,800
Total Annualized Costs 115,000
Cost Effectiveness $/Mg (86.85)^
$/ton (78.81)t
The source of the summary information is the indicated page number(s) in "Control
of Volatile Organic Compound Leaks from Petroleum Refinery Equipment,"
EPA-450/2-78-036.
t
Numbers in parentheses are savings.
C-26
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Table C-23.
SUMMARY OF CTG DOCUMENT FOR EXTERNAL FLOATING ROOF TANKS
Affected
facilities
(p. 1-2)*
External floating roof tanks larger than 150,000 liters (40,000 gal)
storing petroleum liquids. See exceptions noted In text.
Number of
affected
facilities
(p. 2-1)*
There is an estimated 13,800 internal and external floating roof tanks
that are larger than 150,000 liters (40,000 gal). The number of ex-
ternal floating roof tanks is not available.
VOC
emissions
nationwide
(p. 1-2)*
An estimated 65,000 Mg (71,630 tons) of VOC was emitted in 1978 which
represents about 4.0 percent of stationary source estimated emissions.
VOC
emission
range per
facility
(pp. 3-3,
3-9)*
The emission range for a 30.5 m (100 ft) diameter tank storing 41.4 kPa
(6 psl) vapor pressure gasoline is 212 Mg/yr (233 tons/yr) for a slightly
gapped primary seal to 2.2 Mg/yr (2.4 tons/yr) for a tight rim-mounted
secondary seal over a tight primary seal.
100 tons/yr
source size
No single floating roof tank is expected to emit more than 100
tons/yr.
CTG
emission
limit
(PP. 5-1,
5-4)*
A continuous secondary seal or equivalent closure on all affected
storage tanks, pJus certain inspection and recordkeeping requirements.
VOC
reduction
per facility
(pp. 3-3,
3-9) *
Ranges from about 200 to 2 Mg/yr (220 to 2.2 tons/yr).
(pp. 4-9,
4-12) *
Basis:
External floating roof tank 30.5 m (100 ft) in diameter with a
capacity of 8.91 * 106 liters (55,000 bbl) controlled by a rim
mounted secondary seal.
Capital cost
($1000)
Annualized cost
($1000)
Cost effectiveness
($/Mg)
($/ton)
16.9
3.3
(66)^-3,655
(59)+-3,316
*The source of the summary information is the indicated page(s) in "Control of Volatile
Organic Emissions from Petroleum Liquid Storage in External Floating Roof Tanks "
EPA-450/2-78-047. '
Numbers in parenthesis indicate credits.
C-27
-------
Table C-24.
SUMMARY OF CTG DOCUMENT FOR LEAKS FROM GASOLINE TANK TRUCKS AND
VAPOR COLLECTION SYSTEM
Affected
facilities
(p. 2)*
Number of
Affected
facilities
VOC
emissions
nationwide
VOC
emission
range per
facility
CTG
emission
limit
(pp. 1
and 2)
VOC
reduction
per facility
Costs
a. Gasoline tank trucks that are equipped for vapor collection.
b. Vapor collection systems at bulk terminals, bulk plants, and service
stations that are equipped with vapor balance and/or vapor processing
systems.
Not available
Not available
Not available
The control approach is a combination of testing, monitoring, and equip-
ment design to ensure that good maintenance practices are employed to
prevent leaks from truck tanks or tank compartments and vapor collection
systems during gasoline transfer at bulk plants, bulk terminals, and
service stations. A leak is a reading greater than or equal to 100
percent of the LEL at 2.5 cm from a potential leak source as detected by
a combustible gas detector.
Not available
Not available
*The source of the summary information is the indicated page number in "Control of Volatile
Organic Compound Leaks from Gasoline Tank Trucks and Vapor Collection Systems,"
EPA-450/2-78-051.
C-28
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APPENDIX D - EXAMPLE QUESTIONNAIRES
A general discussion of the design and use of questionnaires is presented
in Chapter 3. This appendix contains example questionnaires for inventorying
VOC emissions from solvent use. The inclusion of these questionnaires does
not imply an endorsement by EPA or a requirement to use them. They are
presented merely to show basic structure, possible content, and various
alternatives available.
Additional example questionnaires and background discussion on question-
naire development are available in Reference 1. These questionnaires are
also not required or endorsed by EPA. The reader is simply referred to the
document for additional information.
The primary consideration in developing questionnaires is the inventory
agency's data requirements. The agency's needs will determine whether to
use general or industry-specific questionnaires and what data to elicit.
Discussion on general versus industry-specific questionnaires is included in
both Chapter 3 and Reference 1.
The reader is reminded to observe several caveats when reviewing the
questionnaires in this Appendix. Note that industry-specific questionnaires
must be developed for refineries, chemical manufacturers, and some other
sources. For a VOC emissions inventory, each questionnaire design should be
consistent with the data requirements of emission factors in AP-42, CTG
documents, or any other references. These references should be reviewed
during the development of questionnaires. In addition, local or state
regulations should be consulted before mailing questionnaires to ensure that
all clearance requirements for the forms are met. For example, EPA question-
naire forms must be approved by the Office of Management and Budget prior to
release to more than ten sources. Finally, the reader is reminded to note
the caveats mentioned in Chapter 3.
Reference for Appendix D
1. Development of Questionnaires for Various Emission Inventory Uses, EPA-
450/3-78-122, U.S. Environmental Protection Agency, Research Triangle
Park, NC, June 1979.
D-l
-------
[Agency Letterhead]
Mailing
Label
Dear Sir(s):
The (agency or department) requests your cooperation in providing the
information described on the enclosed questionnaire. The data provided will
be evaluated along with information being gathered from other sources to
determine the impact of hydrocarbon and nitrogen oxide emissions on the air
quality in (geographical area). This request is being made under (statute)
which allows information to be required from sources of air pollution. In
addition, the more nearly complete and accurate the response to the question-
naire, the more valid the conclusion of the study will be.
Certain emission-related data on your equipment or processes have been
extracted from available records. The information requested on the enclosed
forms is not available from current agency records and is needed to assess
base line emissions, control potential, and to project future emissions.
Please complete the enclosed questionnaire and return it within (time period)
to the address indicated on the form.
Any questions regarding these forms should be directed to
(name, address, phone number)
Your cooperation in providing the requested information within (number) days
from receipt of this letter will contribute materially to the accurate
assessment of emissions in (area). Thank you for your assistance.
Sincerely,
(name and title)
Enclosures
Figure D-l. Example Cover Letter.
D-2
-------
GENERAL INSTRUCTION
ORGANIC SOLVENT SOURCE QUESTIONNAIRE
1. All questions should be directed to (name, address, phone number)
2. This questionnaire is aimed at obtaining information from a wide variety
of solvent users. The complete questionnaire includes the following
pages:
Page A - GENERAL INFORMATION
B - DECREASING 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 STACK INFORMATION
3. Data should reflect calendar year (year) or whichever is more readily
available. Specify any other 12-month period that may be used.
4. Fill in the descriptive information and amount of solvent or solvent
containing materials used for each device operating under county permit
as shown in the example on each page.[Note: these examples are for
illustration only and may not represent actual operating conditions.)
5. In the event that data are not available on an individual device basis,
use best estimates from total plant usage to complete Item 4.
6. If the type(s) and/or percentages of solvents in coatings, inks, etc. are
not known, include sufficient information on the manufacturer, type and
stock number so that this breakdown can be obtained. A copy of a supplier's
invoice would be adequate.
7. Complete Pages I, J and K.
8. The emissions data that will be generated during this program will generally
be public information. If certain process, operation, or material information
is considered confidential and should be considered a trade secret, indicate
such (specify a procedure and specify how confidential data will be handled).
Figure D-2. Example Questionnaire-Instruction Sheet.
D-3
-------
Mail Questionnaires in the
Enclosed Envelope To:
ORGANIC COMPOUND EMISSIONS QUESTIONNAIRE
Please Address All Questions To:
NOTE: ALL DATA SIIOIIT.D PFPRESHtlT rAr.FNDAK YF.AR
GENERAL INFOR11ATION
Company Name
Plant Address
City
Mailing Address
City
. ziP_
Zip
Person to Contact About Form
Telephone
Title
Approximate Number of Employees
Nature of Business (Include SIC)
Normal Operating Schedule for Calendar Year
Hrs/Day Days/Week
Approximate Percent Seasonal Operation:
Weeks/Year
Dec. -Teh.
Mar . -May
June-Auq.
Sept. -Nov.
Are hydrocarbon or organic solvent containing materials such as cleaning
fluidb, coatiugb, adheswes, inks, etc. used in your operation?
Y(_,s No If yes, please complete the appropriate forms
. "MakoTaJditiorxU copies if necessary. If organic solvents
are not in use please sign and return.
Signature
Date
Figure D-3. Example Questionnaire-General Information Page.
D-4
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GENERAL SOLVENT USAGE
Type and amount of other solvents not identified with equipment having a
county permit that were used at your facility during calendar year
Do not include any solvents that have been included elsewhere
in this questionnaire.
TYPE AMOUNT tGAL/YR)
SOLVENT RETURNED
List any solvents returned to supplier or collected for reprocessing. Again,
do not include any solvents that have been so specified elsewhere in this
questionnaire.
TYPE AMOUNT (GAL/HR)
Figure D-ll. Example Questionnaire-General Solvent Usage Form.
D-12
-------
BULK SOLVENT STORAGE
Complete the following information for each storage tank .jitatt:r than 250
scrums capacity. (See Editorial Note below)
Annual Type of Fill and
Tank No. Solvent Type Capacity Thrnput Control Equipment*
* Submerged fill, splash fill, return vent line, adsorber.
OPERATIONAL MODIFICATIONS
Please state the changes in type and estimated annual consumption of sol-
vent planned for all operations for calendar years Include
any information on control equipment additions or modifications.
(Editorial Note; This questionnaire should contain space for two additional
pieces of information: tank color and tank condition. The reader
is reminded that these questionnaires are provided as examples and
not as recommended procedures.)
Figure D-12. Example Questionnaire-Bulk Solvent Storage Form.
D-13
-------
CONTROL AND STACK INFORMATION
INSTRUCTIONS:
1. Provide information on all devices that emit organic compounds through a
stack, vent or otlior defined emission point. Identify all units under
separate permits that vent thiouyh d common stack. A simple drawing may
be provided to better illu^Lrate the physical configuration.
2. Identify the primary organic compound control method used (if any) such
as after burners, scrubbers, carbon adsorption, condensers, etc. Note:
this device may have its own permit number. If so, identify.
3. Indicate installation date of control equipment.
4. Indicate approximate efficiency (if known).
5. Provide the following information:
Height - distance above ground to discharge point (feet)
Diameter - inside diameter at discharge point (feet)
Note: if not circular, insert diameter (in feet) of equivalent
circular area which can be calculated by
D •= 1.128 A
where A is the measured or estimated cross-sectional area in sq ft
and De is the equivalent diameter.
Temperature - at discaarge point in "F
Velocity - at discharge point in ft/sec
Flow rate - at discharge in actual cubic feet per minute (ACFM)
Design conditions may oe used in lieu of actual test data.
County
Permit
Number
EXAI1PLE
PQ9099
11C
Control
Taint
After-
burner
Control
Eqmt
Effic.
m
95
Instal-
lation
nato
1969
Stack Data
Height
(ft)
20
Inside
Dia.
(ft)
1.5
Temp
(°n
600
Velocity
(ft/sec)
20
Flow Rate
fft3/min)
2100
Figure D-13. Example Questionnaire-Control and Stack Information Form.
D-14
-------
APPENDIX E - SUPPLEMENTRY INVENTORY DOCUMENTATION DATA DISPLAYS
This appendix provides VOC emission inventory documentation data displays
which are intended to supplement the documentation discussed in Chapter 7.
The following examples are not intended to be exclusive, but rather, they
should act as primers to promote ideas of how an inventory can be documented.
The first three figures require little explanation. Figure E-l shows
the reader what geographical area is covered by the inventory. Population
data are presented in Figure E-2. Figure E-3 is an example highway network
map. This will help persons unfamiliar with the inventory area in assessing
traffic data and other documentation associated with highway vehicle emissions
estimates.
The next four documentation examples relate to emissions projections
and control strategy impact assessment. Figure E-4 shows what years specific
control programs will be applied to the projection year inventories. This
will support the application of control program emissions reductions to
specific years. Quantitative impact of control programs on projected emissions
is shown in Figures E-5 and E-6. Figure E-5 illustrates the incremental
reductions associated with individual control strategies. Figure E-6
documents the cumulative effect of control programs on projected emissions.
Figure E-7 is a listing of control measures planned in an inventory area.
Such a listing will help support the programming of emissions reductions
into projection year inventories.
Finally, the last figure in this Appendix is an example of question-
naire response documentation. Some documentation of this type should be
included in the emissions inventory support materials.
Many additional items can and should be included in the emissions
inventory documentation. The example figures provided in this appendix are
not inclusive of all forms of documentation. The reader should review the
discussion documentation in Chapter 7 prior to developing documentation
materials.
E-l
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Figure E-4 SCHEDULE FOR IMPLEMENTATION OF THE AIR QUALITY MAINTENANCE PLAN
ACTION
YEAR
1978
1980,
1985,
|1990,
1. Use available control technology on
existing hydrocarbon sources.
2. Continue the review of new and
modified Industrial facllles (new
source review), using offsets and
other provisions of the Clean A1r
Act Amendments of 1977. Use technology
to produce lowest achievable emission
rate on new and expanded hydrocarbon
sources.
3. Implement more stringent vehicle
exhaust emission standards.
4. Implement Statewide vehicle Inspection
and maintenance program.
5. Require exhaust control devices on
existing heavy duty gasoline vehicles
Statewide.
7. Preferential parking for carpools and
vanpools.
8. Provide additional transit service
through three-fold transit Improvement
strategy.
9. Support development of high occupancy
vehicle lanes and/or ramp metering
on selected freeway segments when
justified on an Individual project
basis.
10. Provide more ride sharing services such
as jitneys and vanpools.
II. Develop more extensive and safe bicycle
systems and storage facilities.
13. Adopt additional measures to ensure
maintenance of the oxldant standard
beyond 1985-87.
adopt proaram/regulatlon
Implementation
E-5
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i i i r
600
500
400
O
CO
O
00
Z
i 300
w
5
iu
8
T i i
CONTROLS^
1 r
LESS ORGANIC SOLVENT
LESS SECONDARY SEALS
LESS RACT
LESS VALVES AND FLANGES
LESS NEW SOURCE REVIEW
200
100
i i i
i i i
i I i
1979
1982 1985 1987
YEAR
Figure E-6. Example graph of control measures impact on projected emissions.
E-7
-------
Figure E-7 Example Listing of Control Measures
I. Stationary Sources
1. Require the use of high solid 18.
coatings where practical.
2. Require the use of water based
coatings where practical. 19.
3. Adopt the CARB standards for
organic liquid storage. 20.
4. Adopt closed system organic
liquid storage with vapor re- 21.
covery.
5. Require vapor recovery on small 22.
solvent users.
6. Adopt organic solvent regulation
developed by the CARB Organic 23.
Solids Committee.
7. Enact a new maximum 502 emission
limit of 300 ppm. 24.
8. Require reduced sulfur content
in fuels to .025*.
9. Adopt NOX controls for non- 25.
highway and construction equip-
ment.
10. Adopt NOX limits for all new
boilers. 26.
11. Adopt lower partlculate loading
requirement - 0.05 to 0.1 grains/
' SCFM.
12. Adopt lower process weight al- 3?.
lowable scale.
13. Adopt lower process weight maxi-
mum allowable scale.
14. Adopt best available control
technology (BACT) regulation
for existing sources with a 28.
time scale for compliance.
15. Adopt BACT regulation for all
sources In lieu of emission
concentration limits.
16. Adopt BACT regulation for all a)
sources 1n addition to emission
concentration limits.
17. Adoot a modern process tech-
nology rule aimed at promoting
modernization of the areawlde
plant. This might, for In- b)
stance, suspend a BACT rule for
an agreement to modernize a
plant with BACT Included in
modernized version. The Intent
of such a regulation would be
to encourage modernization of c)
old plants with new plants
having Improved pollution con-
trol technology.
Extentlon of current BAAPCO re-
quirements to smaller opera-
tions. I.e., fewer exemptions.
New Source Review (NSR) - con-
tinue present rule.
New Source Review - Adopt 100%
off-set policy.
New Source Review - Adopt 1101
off-set policy.
New Source Review - Adopt a
sliding scale for emission off-
set.
NSR Options 20, 21 or 22 with a
limited area for emission off-
set.
NSR Options 20, 21 or 22 with
Inter-pollutant emission off-
set.
NSR Options 20, 21 or 22 with
no inter-pollutant off-set or
Inter-pollutant off-set governed
by location, etc.
NSR Options 20-25 qualified so
that no credit is allowed for
emissions that are 1n excess of
other limitations.
NSR Options 20-25 with arrange-
ment for off-set banking, allow-
ing a prospective new source
credit for emission reduction
off-set achieved beyond that re-
quired by existing regulations.
Adopt regulations to promote In-
dustrial energy conservation.
29. Plant operation scheduling:
Seasonal scheduling to
reduce polluting opera-
tions during critical
weeks or months as de-
termined by meteorology.
Scheduling maintenance
down time and vacations,
possibly short downs, to
reduce pollutant load at
critical times.
Interruptable operation
dependent upon air quality
conditions.
d) Stagger operations between
plants to spread operation
over seven days instead of
five. Assign plants a 5
day week starting on any-
one of the seven days,
possibly with some on 4
day 10-hour operation.
e) Stagger work hours. For
instance, run coating
lines only between 4 PM
and midnight instead of
7 AM to 3 PM.
f) Schedule reduced work days
during the smog season
with or without longer
days during less critical
seasons. Rationing the
pollution absorbing ca-
pacity.
30. An air monitoring and meteoro-
logical analysis to identify
and recommend mitigation mea-
sures, for certain localized
problems.
31. Adopt particulate regulation
based on particle size.
32. Replace throw-away container
with re-usable containers.
33. Burn solid waste near point of
generation, to reduce long
hauls.
34. Apply 1309 with modified trade-
off of 1311 and 1311-2 clearly
described as an option.
35. Requiring some sort of retro-
fitting on older plants. Ap-
ply BACT to newer plants
through permit system.
36. Penalty charge or tax based on
amount of emission to encourage
reduction.
37. Lowering the reld vapor pres-
sure of gasoline to reduce
hydrocarbon emissions from
storage, handling and use of
motor vehicle grade gasoline.
II. Mobile Sources
1. Implement an evaporative emis-
sions retrofit program for all
vehicles.
I. Implement a catalytic retrofit
program for past-71' vehicles
able to operate on unleaded
gasoline.
3. Adopt more stringent applica-
tion of compliance procedures.
4. Adopt more comprehensive new 8.
and used motor vehicle surveil-
lance program.
5. Adopt a mandatory vehicle In- 9.
spection and maintenance pro-
gram for light and heavy duty 10.
vehicles.
6. Adopt more stringent evapor- 11.
ative emission standards.
7. Implement a heavy duty gasoline
exhaust emission retrofit pro-
gram.
Adopt more stringent exhaust
emission standards for new light
and heavy duty vehicles.
Promote the use of new or modi-
fled fuels.
Promote the use of alternative
power sources.
Establish emission standards for
other mobile sources such as
construction equipment, locomo-
tives, ships, or recreational
vehicles.
E-8
-------
Figure E-7 (ctd.)
III. Transportation Controls
1.
Measures to Improve Traffic
Operations
A. Improve Traffic Flow
1) Computerized traffic
control
2) Ramp Metering
3) Traffic engineering
Improvements
4) Off-street freight
loading
B. Management of Auto Access
B.
Reduce peak-period traffic
volumes
1!
3)
Staggered work hours
Four day work week
Off-peak freight de-
livery
2.
Measures to Reduce Vehicle Use
A. Restrict Vehicle Ownership
1) Additional license fee
2) Registration limits
1)
2)
3)
II
6)
^Better enforcement of
parking regulations
Limit on number of
parking spaces
On-street parking pro-
hibited during peak
hours
Area license
Auto-free zones
Gas rationing <
C. Increase Cost of Auto Use
1)
2)
.1
II
7)
Road prlcinq
Increased parking costs
Parklnq fee for shopper
Eliminate free employee
parking
Increased gas tax
Increased tolls
"Smog charges"
0. Reduce the Need to Travel
1) Communications substi-
tutes
2) Goods movement consol-
idation
3. Measures to Encourage Alternative
Model of Travel
A. Increase Transit Ridershlp
1) Additional transit ser-
vice
2) Fare reductions
3) Improved comfort
4) Bus and carpool lanes
B. Encourage Pedestrian Mode
C. Encourage Bicycle Mode
D. Encourage Ride Sharing
1) Toll reduction for
carpools
2) Preferential parking
and carpools
3) Carpool matching in-
formation
4) Assist vanpool formation
E. Promote Para-Transit
Alternatives
IV.
Land Use Management/
Development Controls
More effective management of all five
major aspects of land development
through coordinated action by cities,
counties, special districts, or re-
gional and State agencies to reduce
the magnitude and frequency of auto
travel:
1. Timing - expand the presently
very limited application of
timing controls such as growth
sequence zoning, building per-
mit quotas, staging of sewer
and water Intrastructure and
plant capabilities, etc.
2. Quantity - expand the presently
scattered application of quan-
titative controls on development
such as performance standard
zoning and limited sewer and
water Infrastructure and plant
capacities.
3. Location - Improve the presently
Inconsistent application of
controls on the location of de-
velopment such as coordinated
management of Infrastructure
location, annexations, public
land acquisition, agricultural
preserves, hillside and soil
conservation, and development
•oratoria.
5.
Density - Encourage transit usage
and other non-auto modes with
coordinated density policies among
local jurisdictions through the
application of Innovative density
zoning mechanisms (slope density,
building height regulations, etc.)
fuJly coordinated with service
capacities and commitments.
Type - Reduce home-to-work A home-
to-non-work travel by encouraging
more land use mix, especially in
terms of housing/jobs balance.
E-9
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APPENDIX F - EPA EMISSIONS DATA SYSTEMS
F-l NATIONAL EMISSIONS DATA SYSTEM (NEDS)
The National Emissions Data System is a computerized data handling
system which accepts, stores and reports on source and emissions information
relating to any of the five criteria pollutants (Total Suspended Particulate,
S02> N0x, CO and Hydrocarbons). In NEDS, a major distinction is made between
point sources and area sources. Although by EPA definition (40 CFR 51),
point sources are any facilities that emit more than 100 tons/year, they
are in the broadest sense, stationary sources large enough to be identified
and tracked individually. Area sources, on the other hand are those stationary
and mobile sources which individually emit less than 100 ton/year and are
too small and too numerous to keep individual records on. Area sources are
compiled collectively on a county basis. A large boiler within a power
plant would be an example of a point source, whereas a single automobile is
an example of the type of source collectively considered an area source.
In NEDS, all source related data are entered into the system on specially
formulated point and area source coding forms and are stored in separate
point and area source files. Point and area source are data stored in the
system are briefly described below.
Point Source Data -
General source information: Name, address, source type, year of
record, comments, etc.
Emissions data: Operating or production rate, estimated emissions,
EPA calculated emissions, control device type and efficiency for
each criteria pollutant, etc.
Modeling parameters: UTM coordinates, stack height and diameter,
exhaust gas temperature, flow rate, etc.
Area Source Data -
%
General source information: Name and location of area (county)
source, year of record.
Activity levels: Countywide activity levels of each type of area
source (e.g., tons of coal burned in all domestic space heating
equipment in a county).
Emissions data: Emission estimates for the entire county, for
each pollutant and for each area source category.
Currently in NEDS, information is being maintained on over 55,000
point sources (plants) and about 3,100 area (county or county equivalent)
sources in the 55 states and territories of the United States. The point
F-l
-------
source total will fluctuate as additional sources are reported, new sources
come into operation, or old sources cease operations. The number of area
sources is fixed by the number of counties in the United States.
The information contained in these files changes, too. As plants add
to, modify, or change the operation of their equipment, use different fuels,
etc., the point source data must be continually updated to reflect these
changes. Likewise, as the activity levels of the various area sources
change (more vehicle miles may be traveled by automobiles in a county, more
oil and less gas may be burned for home heating, etc.) their records must
likewise be updated. By EPA requirement (40 CFR 51), it is the responsibility
of the states to maintain point source data. Area source data, because of
their composite nature, are collected, apportioned, and maintained centrally
by EPA, although state supplied data will be accepted if they are more
accurate and adequately documented. All submitted data are edited and
validated prior to being accepted into the system. In addition to the point
and area source files, NEDS emission factor files are kept current with the
latest AP-42 information.
The most important function of NEDS is report generation. NEDS output
ranges from reports on individual point and area sources to sophisticated
summaries which aggregate data in a variety of ways and condense data from
many sources into one report. Also, because of the NEDS file design numerous
selection and sorting criteria can be specified by the users of the system.
The following describes the more important reports available from NEDS.
This is not a complete list, since NEDS is continually being expanded to
meet additional user needs.
Complete point or area source listing - These reports include, in a
standard format, all of the source and emissions data sorted in NEDS for
individual point or area sources. This includes all of the data supplied to
NEDS on point and area source input forms, as well as any emission estimates
calculated by EPA through the use of emission factors.
Condensed point source listing - This report yields an abbreviated
listing of data items for each point source, including the plant name,
location, control device and efficiency, and the emissions associated
therewith.
Emissions summary report - This report lists, for a specific geographical
area, emissions of each of the criteria pollutants associated with all of
the source categories represented in NEDS, as well as the total emissions
for all source categories.
Plant emissions report - This report presents a listing of the names of
plants in NEDS and the emissions associated with each plant.
Fuel summary listing - This report tallies the type and amount of fuel
consumed by all stationary and mobile source categories for a specified
geographical area. This report includes both point and area source records.
F-2
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Quick look report - This is a one line report for selected NEDS point
or area sources. Only data items printed which are specified by the user.
Emissions by SCC (Source Classification Code) report - This report
shows each SCC, the number of times that SCC occurs within a specified
geographical area, and the total emissions for each of the five pollutants
associated with each SCC. (Note that a SCC number is a code used in NEDS to
represent different kinds of point source categories.)
NEDS is currently operational on a UNIVAC 1110 located at Research
Triangle Park, NC. It is accessible in interactive and remote batch modes
by EPA headquarters and regional personnel. The system is not routinely
available to users as a software package to be run on their own computers.
However, descriptions, flow charts, and other documentation are available in
the AEROS Manual Series publications that are obtainable from EPA to qualified
requesters and, for others, from the National Technical Information Center
(NTIS), 5285 Port Royal Road, Arlington, VA 22161. Consult the AEROS/NEDS
contact in the appropriate EPA Regional Office for further details and
assistance in obtaining the proper publications and information.
F-2 THE EMISSIONS INVENTORY SYSTEM/PERMITS AND REGISTRATION SUBSYSTEM
(EIS/P&R) OF THE COMPREHENSIVE DATA HANDLING SYSTEM (CDHS)
The Comprehensive Data Handling System (CDHS) is intended to aid State
and local air pollution control agencies in performing their daily operations
and to ease their job of meeting EPA reporting requirements.
The CDHS actually comprise two basic and important subsystems which may
be operated independently. These subsystems are:
The Emissions Inventory/Permits and Registration Subsystem (EIS/P&R)
The Air Quality Data Handling Subsystem - II (AQDHS-II)
The CDHS subsystems (software) are provided to state and local air
pollution control agencies at no charge. Each agency installs the subsystems
on a computer to which it has access. The agency can then build and maintain
its own data base. The computer programs which comprise each subsystem are
maintained by EPA. Of these, EIS/P&R is of interest in the context of
emission inventories.
The EIS/P&R subsystem provides a means for monitoring point and area
source engineering and emissions data. It has special capabilities for
recording permit data, and it can handle narrative information such as rules
and regulations. EIS/P&R also provides means for handling special data of
local importance while maintaining full compatibility (for reporting purposes)
with Federal requirements. EIS/P&R is especially significant, since it can
be used to support such agency activities as permit control, source inventory,
legal actions, and the monitoring and recording of enforcement and inspection
activities. A simplified diagram of the basic concept of EIS/P&R is shown
in Figure F-l.
F-3
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The interested agency should consult the appropriate EPA Regional
Office for more information on what EIS/P&R can do and how to obtain it. It
may also contact the National Air Data Branch, (MD-14), U.S. Environmental
Protection Agency, Research Triangle Park, NC 27711.
F-5
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing/
1. REPORT NO. 2.
EPA 450/2 77 028, 2nd Edition
4. TITLE AND SUBTITLE
'rocedures for the Preparation of Emission Inventories
for Volatile Organic Compounds: Volume I
Second Edition
7. AUTHOR(S)
9. PERFORMING ORGANIZATION NAME AND ADDRESS
EPA, Office of Air Quality Planning and Standards
Monitoring and Data Analysis Division
Research Triangle Park, NC 27711
12. SPONSORING AGENCY NAME AND ADDRESS
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
September 1980
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
1O. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
Principal Authors - William H. Lamason, II and Tom Lahre
6. ABSTRACT
Procedures are described for compiling emission inventories of volatile organic
compounds (VOC) for use in less data-intensive models such as rollback and the
Empirical Kinetic Modeling Approach (EKMA). Such inventories generally represent
annual emissions (perhaps with some seasonal information) and are compiled for
Larger geographical areas such as counties.
The basic inventory elements—planning, data collection, emission estimates,
and reporting—are all discussed. No single prescriptive methodology is presented;
rather, a set of procedures is described so that the agency may choose the most
appropriate techniques to meet its needs in its ozone program. Various examples are
included to aid the agency in the understanding and utilization of this document.
17 KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
Emission inventory Volatile organic
Hydrocarbons compounds (VOC)
Inventory VOC
Mail survey
Organics
Questionnaires
Survey
18. DISTRIBUTION STATEMENT
Unlimited
b. IDENTIFIERS/OPEN ENDED TERMS
19. SECURITY CLASS (This Report)
Unclassified
20. SECURITY CLASS (This page)
Unclassified
c. COS AT I F'ield/Group
21. NO. OF PAGES
214
22. PRICE
EPA Form 2220-1 (Rev. 4-77)
PREVIOUS EDITION IS OBSOLETE
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