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


                               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
            Office of Air, Noise, and Radiation
         Office of Air Quality Planning and Standards
         Research Triangle Park, North Carolina 27711

                September 1980

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


     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.

                              TABLE OF CONTENTS
Section                                                            Page


     1.1  Purpose 	  1-1
     1.2  Contents Of Volume I 	  1-2

     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

     3.1  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


     4.1  Introduction 	  4-1
          4.1.1  Area Source Inventory Structure And Emphasis ....  4-1
          4.1.2  Source Activity Levels 	  4-3

          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
         Tank Truck Unloading (Stage I)  	  4-9
         Vehicle Fueling And Underground
                            Tank Breathing 	  4-10
         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
         Open Top And Conveyorized Degreasing ...  4-16
         Cold Cleaning Degreasing 	  4-17
          4.3.3  Surface Coating 	  4-18
         Architectural Surface Coating 	  4-19
         Automobile Refinishing 	  4-20
         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
         Off-highway Motorcycles 	  4-32
         Farm Equipment 	  4-32
         Construction Equipment 	  4-33
         Industrial Equipment 	  4-34
         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



Section                                                            page

     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

   •  7.1  Reporting Forms 	 7-1
     7.2  Supporting Documentation 	 7-2


                              1.0 INTRODUCTION

     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

     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.

     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*


     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


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.




     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.

     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.


     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

      °    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?


                     DESIGN AND ASSEMBLE
                      MAIL QUESTIONNAIRES



                                 REMAIL THOSE
                                 DUE TO
.._ 1 SOURCE
NO 1 <,.7f: „„



                                                                                          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
                                                            RECONTACT FOR ADDITIONAL DATA
     IDENTIFY AREA       I
     IN THE AREA         I
         PERCENT OF
         TOTAL IN EACH
        FOR EACH
               TO ACHIEVE LEVEL OF
               EFFORT/ACCURACY FOR
               TO BE CONSIDERED
                                                           DETERMINE IF DATA RECEIVED IS
                           I'               '
                                          [  OBTAIN DESIRED PUBLICATION  |-
              \iumwVoi " i > [CONTACT & REQUEST DESIRED INFORMATION

                                       RECEIVE AND LOG IN RESPONSES

                           FILING AND
                                                                       NON RESPONDANTS
                                                        REMAIL THOSE
                                                        RETURNED DUE
                                                        TO INCORRECT
                              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
                                                                CALCULATE EMISSIONS FOR EACH GRID
                                                                OR FOR THE SMALLEST AREA FOR WHICH
                                                                DATA IS AVAILABLE WHICHEVER LARGER
                                                                        APPORTION THOSE EMISSIONS WHICH ARE
                                                                        ON A GEOGRAPHICAL BASIS LARGER THAN
                                                                        THE GRIDS INTO THE GRIDS
                                              DATA GATHERING
         Figure 2.1-1.  Flow chart of VOC emission inventory compilation activities (Radian, 1977).

     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

     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

     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

      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.


      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


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


     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

     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.


  Table 2.2-1.  Volatile Organic Compound (VOC)  Emission  Sources.

  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)


  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


  Large Appliances
  Magnet Wire
  Metal Coils
  Metal Wood Products
  Miscellaneous Metal  Products
  Plastic Parts Painting
  Large Ships
  Large Aircraft

  Architectural Coatings
  Auto Refinishing


  Dry Cleaning
  Graphic Arts
  Cutback Asphalt
  Solvent Extraction Processes
  Consumer/Commercial Solvent Use


  Fuel Combustion
  Solid Waste Disposal
  Forest, Agricultural, and Other
     Open Burning
  Pesticide Application
  Waste Solvent Recovery
  Stationary  Internal Combustion


  Highway Vehicles
     a.  Light  Duty Automobiles
     b.  Light  Duty Trucks
     c.  Heavy Duty Gasoline
     d.  Heavy Duty Diesel  Trucks
     e.  Motorcycles

   Off Highway Vehicles
 -"-Includes all storage facilities except those at service stations  and bulk
  Loading tank trucks and rail cars.
  Storage and transfer operations.


     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.


     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

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.


     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.


     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.


     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.


      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.


     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

     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.


     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.


     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.


     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:

          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.


     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


     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.

     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

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


     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.


     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.


     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

     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

      If the agency anticipates use of a photochemical dispersion model at
 some future date, it is imperative  that a computerized data handling system


be utilized.  The added complexity involved in developing spatially and
temporally resolved estimates of several VOC classes from the basic 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.


     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

     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

     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

     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


           0 Plan to  allocate resources for maximum quality  assurance.

           0 Plan to  account for  significant VOC emission  sources.


            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
            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
     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.


     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.


     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


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.


     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

     0    Procedures for identifying nonreactive emissions have been selected.

     0    The agency has decided on how emissions  will be projected and the
projection period, including end year and intermediate years,  has been

     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,

 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

 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,  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

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,

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.

                       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.


     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.


     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.


     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

          - 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

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.


     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.

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
Ranges (tons/employee/yr)
 20   Food

 21   Tobacco

 22   Textiles

 23   Apparel

 24   Lumber & wood

 25   Furniture &

 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
Not surveyed

Coating (2295),
Non-wovens (2297),
Dyeing (2231)
Not surveyed

Finished product (2435),
SIC:  (2511),  (2514),
(2521), (2522),  (2542)

Bags, box (2643),
(2651), (2653),
Coated papers
Newspaper publishing
(2711), Comm.
printing (2751),
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
Screws  (3451-2), Metal
stampings  (3469), Plating
(3471),  Tool mfg. (3423),
Industrial machines
Devices  (3643), Semicond.
Boats (3732), Truck bodies
 (3711),  13, 14, 15)
Optical  frames  (3832)
Precision instruments
Jewelry (3914-15),  Toys
 (3944),  Writing instr.

All surveyed

 All surveyed













     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.)

     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,


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

     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.


     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


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)
                     COMPANY NAME,
                     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.

     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-

     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.


     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.



     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.


     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.


     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,

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


     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.

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

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,

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.

                       4.0  AREA SOURCE DATA COLLECTION


     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


     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.

                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
               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

     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.


     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.


     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

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


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

     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


     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.


     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


     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.


  End Users
                         Storage Tank
                         Loading Rack
                        Tanker Truck
                         Storage Tank
                         (Fixed Roof)
                        Loading Rack
 Storage Tank
                 Transport Out of
                  Inventory Area
                 Transport From
                   Other Areas
                 Transport Out of
                  Inventory Area
 Transport From
Outside Inventory

                              Transport •

                              Transfer -

                              Breathing •

                              Transfer —
                                                                 — Source
                    Figure 4.2-1.  Gasoline Marketing Operations and Emission Sources4.

     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.

     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


     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.  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

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.  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.^  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

     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


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.


     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.


     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

     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.

     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.

     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

               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


     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.

     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

      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.

                                                       I k  (B) Emissions
Distributors of
     Solvent Reclaimed
      by Reprocessor
 Degreasing Including
    Cold Cleaning
and Vapor Degreasing
                          (A) Emissions
 Solvent and
                                                                                       (C) Emissions
                                                         Control or
                                                     Permanent Capture
                                                     Emissions Fraction
     Waste Solvent
Open Storage
Landfills  and  Dumps
Deep Well  Inject
                              Used Solvent
                                Sold to
                                                       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.  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.

     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.  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

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

     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.


      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.

-------  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


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.  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.  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.


     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,


     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.

     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.


     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

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


     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).


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.


      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


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.


     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.


     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.


     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.


     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 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

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


 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


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).

     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

     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

     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.


     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.  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

     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.  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.



Device Annual
General Purpose
Fuel consumption rate
Gasoline Diesel
Population density
Gasoline Diesel
 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.  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.


Equipment type
Lawn and garden
243 x
612 x
827 x
25 x
80 x
10 6
4,453 x
1,094 x


     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. 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.  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
                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
                       C  = 1 for counties with more than 30 inches annual

                NSC = National  snowthrower  fuel consumption

                CP  = County population


               CS  = County snowfall

               SZP = Snow zone population (population of all counties with
                     more than 30 inches annual snowfall: 116,049,900

               SZS = Snow zone snowfall (sum of snowfalls in all counties
                     with more than 30 inches annual snowfall: 101,437.74

     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.

     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

     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


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.


     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.

                       BURNED IN ON SITE INCINERATION3

Residential Commercial/Institutional Industrial
EPA (Tons/1000 (Tons/1000 population/ (Tons/1000 mfg
Region population/yr) yr) employees/yr



 References 21, 40, 52, 53.


     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


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.

                            THROUGH OPEN BURNING3
          Residential     Commercial/Institutional       Industrial
           (Tons/1000      (Tons/1000 population/       (Tons/1000 mfg
          population/yr)	yr)	employ ees/yr
fReferences 21, 40, 52, 53, 55.
 For rural population only.  Open burning assumed banned in urban areas.


     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


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.


     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

     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:

  consumed = # of oil burners x avg size (BTU/hr) x 8760 (hr/yr) x load
                                140,000 BTU/gallon

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.


     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.


     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

      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


         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
               I = regional  average consumption  for  water heaters, therms

               J = number of occupied dwelling units using  LPG for water
               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

     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.


     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:   >
     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.


     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.


      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


     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.


     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.


     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


      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


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.

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

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

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.

 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

 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-

 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.


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

65.  Mineral Industry  Surveys, "Natural Gas Production and  Consumption",
      Bureau of Mines,  U.S. Department  of the Interior,  Washington,  DC, 1970.

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.


     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:

                        Office of Transportation and
                               Land Use Policy
                              401 M Street, SW
                            Washington,  DC  20460

                         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.


     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.

     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.

                             Source Test Results
Run Number
Stack flow rate (scfm)
% Excess air
CO emissions (ppm, by volume)
VOC emissions
(ppm, by volume, as CH.)



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



     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

      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,


 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

     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


     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

     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


(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.


     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.


      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)
      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.
           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).

          P  =5.4 psia (from Figure 6.3-1, for 10 psi Reid vapor pressure
                 gasoline and T  = 62.5°F).
          P  =14.7 psia (assumed).
          P* =       14.7              _
               [ 1 + (1 - 5.4 )u.5]2

          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

     Withdrawal loss - Calculate the withdrawal loss from  Equation 6.3-2

          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,


-------An error occurred while trying to OCR this image.

-------An error occurred while trying to OCR this image.

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.


     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)

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.

     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

     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.


     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:

     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

     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


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

     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


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

     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


     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.


-------An error occurred while trying to OCR this image.

     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.


     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.


     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)
               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

               F  = Paint factor (dimensionless)

               C  = Adjustment factor for small diameter tanks
               K  = Crude oil factor (dimensionless); See note (2) below

     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.


     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.


     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.


     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.


     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.


     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.


     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,

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.


     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


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

        TABLE  6.7-1.  Growth  Indicators for Projecting Emission Totals
                         for  Area Source Categories19
 Source Category

 Gasoline handling

  surface coating

Cutback asphalt
Miscellaneous solvent
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
 Information  Sources

 U.S. Department of
 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

Local MPO
Aircraft, commercial,
  and general
Aircraft, Military
Agricultural 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

  TABLE  6.7-1.
(cont.).   Growth Indicators  for Projecting  Emission  Totals
         for Area Source Categories
Source Category

Lawn and garden

Off highway motor-
  cycles snowmobiles,
  and small pleasure


Ocean-going and
  river cargo vessels
Residential fuel

  fuel combustion
Industrial fuel
Solid waste disposal,
  on site incineration,
  open burning

Fires:  Managed
  burning agri-
  cultural field
  burning, frost
  control (orchard

Fires: forest
  structual fires
         Growth Indicators

         Single-unit housing
         or population

         Revenue ton—miles

         Cargo tonnage
         Residential housing
         units or population

         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
Local MPO, land use


      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.

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.

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

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.

     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.


     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

     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.

-------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

      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


     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


                   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
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


-------An error occurred while trying to OCR this image.

                                   VOLATILE ORGANIC COMPOUND EMISSION TRENDS






 I  600


"?  500































               Figure 7.1-3. Example bar chart to illustrate source category contributions to total emissions
               and projected emission trends.

                    Figure 7.1-4
350 -
200 -
150 •


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".

          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

          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
          d.   Any assumptions made regarding the data received or not

          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:


          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.


 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.

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

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:   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).

 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.


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

 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).

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

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

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).


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.


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.

     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

     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.

                   Principal Emitting Operations at Major
                            VOC Source Categories
Name and Location
Major VOC Source Category
Principal Operations
           Figure B-l.   Point  Source  Process  Emission  Reporting  Sheet,


                                 TABLE B-l.



     Oil and Gas Production and Processing
          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

     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


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)



     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
            Battery Stacks
          Electric Arc Furnaces
          Other Process Units (Specify)

     Synthetic Fiber Manufacture
          Dope Preparation
          Fiber Extrusion - Solvent Recovery
          Takeup Stretching, Washing, Drying,  Crimping,  Finishing
          Fiber Storage - Residual Solvent Evaporation
          Equipment Cleanup
          Solvent Storage
          Other Process Units (Specify)


     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)


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)

     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
     Over Varnish
     Coating Mixing
     Coating and Solvent Storage
     Equipment Cleanup
     Other Process Emissions  (Specify)

     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)


     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
     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)


     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)


     Dry Cleaning

          Open Top Vapor Degreasing
          Conveyorized Degreasing - Vapor
          Conveyorized Degreasing - Cold Cleaning

     Solvent Extraction Processes

          Adhesive Application
          Solvent Mixing
          Solvent Storage
          Other Process Emissions  (Specify)

     Graphic Arts
          Letter Press
          Offset Lithography
          Ink Mixing
          Solvent Storage


     Waste Solvent Recovery Processes


     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

     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
     0    Surface Coating of Large Appliances (EPA-450/2-77-034).

     0    Storage of Petroleum Liquids in Fixed Roof Tanks
     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
     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.

     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

     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
     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
     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
     0    Perchloroethylene Dry Cleaning Systems  (EPA-450/2-78-050).

     0    Leaks from Gasoline Tank Trucks and Vapor Collection Systems

     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


           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


     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.

                   Table C-l.
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

                                Table C-2.
 AFFECTED  I      Coil  surface coating  lines  including  the  application  areas,  tnt
FACILITIES ! ing ovens, ana the quench  areas.
     Estimated to be 180 facilities  nationwide.
     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.
Averaqe annual VOC emission for a typical facility is estimated
to be 180 Kg (200 ton) .
 100  TON/YR
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
     The  reconroended VOC emission  limit  is 0.31 kg per  liter of coating
 minus water  (2.6  Ib/gal}.
      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.                                                	
      BASIS:   15,000 scfm  facility using incineration witr, primary heat
      Capital cost:             ~ $170,000
                  Annualized cost:
                  Cost effectiveness:
                                  $ 70,oo:
                                  $51  - $94 per ton VOC

                    Table  C-3.
100 TON/YR
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.
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,).
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:

                      Table C-4.
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 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

-------An error occurred while trying to OCR this image.

                 Table  C-6.
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.

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

                 Table C-7.
100 TON/YR
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

                            Table C-8.
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
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

                       Table  C-9.
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
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

             Table C-10.
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', .
Emission limits recommended in terms of equipment specification
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

                      Table C-ll.
100 TON/YR
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
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

-------An error occurred while trying to OCR this image.

                                    Table  C-13.
     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.
     No estimates of the number of individual  facilities  are
available.  There are approximately 285 refineries  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.
     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
     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
x 10° bbl)
                                               x 10" bbl)
                                         (0.67 x 10° bbl)
     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
     Implementing the recommended controls can reduce VOC emissions bj<:
     a. VPS - 100 percent
     b. WS  -  95 percent
     c. PUT -  98 percent.
     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

                    Table C-14.
100 TON/YR
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

                                   Table  C-15.
     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
       c.  Conveyorized degreaser:  continuously loaded, conveyorized
           solvent degreaser, either boiling or nonboiling.
     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.
     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.
     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.
     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
     Data indicate that on an average 10 open top degreasers or 4 con-
veyorized degreasers may emit 100 ton/yr.
     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
     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
Capital Cost
0.3 - 10.3
7.5 - 18
Annual ized Cost
(0.8) - 0.8
3.7 - 1.5
* ($---} indicates savings
Cost Effectiveness
$/ton VOC
(360) - 220
(260) - 260


-------An error occurred while trying to OCR this image.

-------An error occurred while trying to OCR this image.

                       Table  C-18.
(p. 1-4)*
Number of
(p. 1-2)*
amis B ions
range per
100 ton/yr
source size
(p. 1-5)*
p«r facility
(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,"

                                      Table  C-19.
(pp. 1-1,
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
(p. 2-2)*
Maximum of 62 rubber tire plants 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.
range per
(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.
(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.
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.
(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

                Annual!zed cost

                Cost effectiveness

                                  Bead dipping

              Tread end

             Green tire

*The source of the summary information is the indicated page(s)  in  "Control
 of Volatile Organic Emissions from Manufacture  of Pneumatic  Rubber Tires  "

                                Table  C-20.

                             AND FLEXOGRAPHY
(p. l-D*
Nuntoer of
(p. 2-5)*
(p. 2-8)*

e ml SB Ion
range per
100 tons/yr
source size
(pp. 1-2,
1-3) *

per facility

(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.


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

. .
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,
VOC concentration ppm
Capital cost
Annuallzed cost
Cost effectiveness)





i 1,200


7 ,000
7(U ,000

( 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.

                                    Table C-21.
(p. 2-1)*
Number of
(pp. 1-2,
2-1) *
range per
(p. 5-2)*
100 tons/yr
source size
(pp. 6-1 -
per facility
(pp. 2-5,
(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.

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,

                                   Table C-22.
(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
There were 311 petroleum refineries in the nation as  of
January 1, 1979.
(p. 5-1)*
The estimated VOC emissions nationwide are 170,000 Mg/year,
or about 1 percent of the total VOC emissions from stationary
range per
(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.
 (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.
 reduction  per
 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
 (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,"
  Numbers in parentheses are savings.

                                            Table C-23.
(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
(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.
(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.
range per
(pp. 3-3,
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
(PP. 5-1,
A continuous secondary seal or equivalent closure on all affected
storage tanks, pJus certain inspection and recordkeeping requirements.
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) *
        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

                        Annualized  cost

                        Cost effectiveness
*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.

                                     Table C-24.
                             VAPOR COLLECTION SYSTEM
(p. 2)*

Number of
range per
(pp. 1
and 2)
per facility
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

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,"

     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.

                           [Agency Letterhead]
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.

                                     (name and title)

                     Figure D-l.  Example Cover Letter.

                               GENERAL INSTRUCTION


 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
               G - OVENS
               H - PRINTING
               I - GENERAL SOLVENT USE
               J - BULK SOLVENT STORAGE

 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.

Mail Questionnaires in the
Enclosed Envelope To:

                      Please Address All  Questions To:


      Company Name	

      Plant Address  	
       Mailing Address
. ziP_

       Person to Contact About Form

       Approximate Number of Employees
       Nature  of  Business  (Include SIC)
       Normal Operating Schedule  for Calendar Year

         	Hrs/Day 	Days/Week

       Approximate Percent Seasonal Operation:
Dec. -Teh.

Mar . -May


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.
    Figure  D-3.   Example Questionnaire-General Information Page.

-------An error occurred while trying to OCR this image.

-------An error occurred while trying to OCR this image.

-------An error occurred while trying to OCR this image.

-------An error occurred while trying to OCR this image.

-------An error occurred while trying to OCR this image.

-------An error occurred while trying to OCR this image.

-------An error occurred while trying to OCR this image.

                        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
             TYPE                           AMOUNT  (GAL/HR)
  Figure D-ll.   Example Questionnaire-General  Solvent Usage Form.

                                 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.

                             CONTROL AND STACK  INFORMATION
      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.




Stack Data




Flow Rate

Figure  D-13.   Example  Questionnaire-Control  and  Stack Information Form.


      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

      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

-------An error occurred while trying to OCR this image.

-------An error occurred while trying to OCR this image.

-------An error occurred while trying to OCR this image.

  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

  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

  7. Preferential  parking for carpools and

 8. Provide additional  transit service
    through three-fold  transit Improvement

 9. Support development of high occupancy
    vehicle lanes and/or ramp metering
    on selected freeway segments when
    justified on  an Individual  project

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


-------An error occurred while trying to OCR this image.

                    i      i      i       r

i   300



                                                     T      i       i

      1      r
                                                              LESS ORGANIC SOLVENT
                                                              LESS SECONDARY SEALS
                                                             LESS RACT

                                                             LESS VALVES AND FLANGES
                                                              LESS NEW SOURCE REVIEW
              i       i       i
                                        i      i      i
i       I      i
                                   1982                1985           1987

             Figure E-6. Example graph of control measures impact on projected emissions.

                        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.
 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-
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-
     NSR Options 20, 21 or 22 with a
     limited area for emission off-
     NSR Options 20, 21 or 22 with
     Inter-pollutant emission off-
     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
      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-
30.   An  air monitoring and  meteoro-
      logical analysis to identify
      and recommend mitigation mea-
      sures, for certain localized
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
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
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
 I.    Implement a catalytic retrofit
      program for past-71' vehicles
      able to operate on  unleaded
 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.
6.   Adopt more stringent evapor-        11.
     ative emission standards.
7.   Implement a heavy duty gasoline
     exhaust emission retrofit pro-
      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

                                               Figure  E-7  (ctd.)
                                          III. Transportation Controls
     Measures to Improve Traffic

     A.   Improve Traffic Flow

          1)   Computerized traffic
          2)   Ramp Metering
          3)   Traffic engineering
          4)   Off-street freight
                                          B.   Management of Auto Access
          Reduce peak-period traffic
          Staggered work hours
          Four day work week
          Off-peak freight de-
Measures to Reduce Vehicle Use

A.   Restrict Vehicle Ownership

     1)   Additional  license fee
     2)   Registration limits



    ^Better enforcement of
       parking regulations
     Limit on number of
       parking spaces
     On-street parking pro-
       hibited during peak
     Area license
     Auto-free zones
     Gas rationing <
                                          C.   Increase Cost of Auto Use


Road prlcinq
Increased parking costs
Parklnq fee for shopper
Eliminate free employee
Increased gas tax
Increased tolls
"Smog charges"
                                               0.    Reduce  the  Need  to Travel

                                                    1)    Communications substi-
                                                    2)    Goods  movement consol-
3.   Measures to Encourage Alternative
     Model of Travel

     A.    Increase Transit Ridershlp

          1)   Additional  transit ser-
          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
          2)   Preferential parking
                 and  carpools
          3)   Carpool  matching in-
          4)   Assist vanpool  formation

     E.    Promote  Para-Transit
                                            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

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

                                  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
                               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.

-------An error occurred while trying to OCR this image.



      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


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

      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.


      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.


      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.


-------An error occurred while trying to OCR this image.

     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.

(Please read Instructions on the reverse before completing/
1. REPORT NO. 2.
EPA 450/2 77 028, 2nd Edition
'rocedures for the Preparation of Emission Inventories
for Volatile Organic Compounds: Volume I
Second Edition
EPA, Office of Air Quality Planning and Standards
Monitoring and Data Analysis Division
Research Triangle Park, NC 27711
September 1980
Principal Authors - William H. Lamason, II and Tom Lahre

     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.
Emission inventory Volatile organic
Hydrocarbons compounds (VOC)
Inventory VOC
Mail survey

19. SECURITY CLASS (This Report)
20. SECURITY CLASS (This page)

c. COS AT I F'ield/Group

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