United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-450/4-79-006
December 1978
Air
Development of an
Emission inventory
duality Assurance
Program

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                               EPA-450/4-79-006
Development of an Emission
Inventory Quality Assurance
               Program
                    by

               PEDCo Environmental, Inc.
                11499 Chester Road
               Cincinnati, Ohio 45246
               Contract No. 68-02-2585
                 Assignment No. 8
                  PN 3327-H
                  Prepared for

          U.S. ENVIRONMENTAL PROTECTION AGENCY
             Office of Air, Noise, and Radiation
          Office of Air Quality Planning and Standards
          Research Triangle Park, North Carolina 27711

                 December 1978

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This report is issued by the U.  S.  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
contractors and grantees, and nonprofit  organizations  -  in limited
quantities - from the Library Services Office (MD-35), Research
Triangle Park, NC  27711; or, for a fee, from the National  Technical
Information Service, 5285 Port Royal  Road, Springfield,  VA  22161.
This report was furnished to the Environmental  Protection  Agency by
PEDCo Environmental, Inc., 11499 Chester Road,  Cincinnati,  OH,  45246
in fulfillment of Contract No.  68-02-2585.   The contents of this report
are reproduced herein as received from PEDCb Environmental, Inc.  The
opinions, findings and conclusions expressed are those  of  the author
and not necessarily those of the Environmental  Protection  Agency.
Mention of company or product names is not  to be considered an
endorsement by the Environmental Protection Agency.
                 Publication No.  EPA-450/4-79-006
                                 n

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                        TABLE OF CONTENTS

                                                            Page,

List of Figures                                              iv

List of Tables                                               iv

Acknowledgment                                                v

Executive Summary                                            vi

1.0  Introduction                                             1

2.0  Quality Assurance Elements                               3

     2.1  Definition of Quality Assurance                     3
     2.2  Development of a Quality Assurance Program          4

3.0  Analysis of the Emission Inventory Process               6

     3.1  Task Planning                                       6
     3.2  Data Collection                                    11
     3.3  Technical Procedures                               14
     3.4  Data Recording and Reporting                       17

4.0  Error Potential in.the Emission Inventory Process       20

     4.1  Typical Errors                                     20
     4.2  Control Techniques                                 28

5.0  Implementing Quality Assurance Procedures               32

     5.1  The Role of Federal Guidance in Quality
          Assurance Program Development and Imple
          mentation                                          33
     5.2  Regulatory vs. Voluntary Approach                  35

Appendix A                                                   38

Appendix B                                                   42
                              111

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                         LIST OF FIGURES
No.                                                         Page

2-1  Procedures Fox Developing a Quality
     Assurance Program                                        5

3—1  Major Steps in the Emission Inventory Pro-cess            7
                         LIST OF TABLES


No.                                                         Page

3-1  Task Planning for the Emission Inventory Process         8

3-2  Data Collection Procedures in the Emissions
     Inventory Process                                       11

3-3  Technical Procedures in the Emission Inventory
     Process                                                 15

3-4  Data Recording and Reporting Procedures in the
     Emissions Inventory Process                             17

4-1  Errors and Error Sources in the Emission
     Inventory Process                                       26

4-2  Examples of Preventive Quality Assurance Techniques.    29

4-3  Examples of Corrective Quality Assurance Techniques     30
                              xv

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                         ACKNOWLEDGMENT

     This report was prepared for the U.S. Environmental Protec-
tion Agency by PEDCo Environmental, Inc., Cincinnati, Ohio.  David
W. Armentrout was the principal author.  Charles E. Zimmer was
the Project Director for PEDCo.
     Mr. Jamee Southerland was the task officer for the U.S.
Environmental Protection Agency.  We wish to thank him for his
guidance and professional opinions offered throughout this task.

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                        EXECUTIVE SUMMARY

     The 1977 Amendments to the Clean Air Act include require-
ments for the Prevention of Significant Deterioration (PSD), New
Source Performance Standards (NSPS),  emission offsets, reasonable
further progress, and other considerations that could increase
the number of users and the significance of emission inventory
data.  These considerations involve  an increasing audience of
private users from the industrial community in addition to the
traditional users associated with control strategy development
and assessment.   To make the inventory data and the policies
based on them more representative and equitable,  to both public
and private interests, quality assurance guidelines for emission
inventories (similar to those designed for ambient air monitoring
systems)  are desirable and necessary.
     Quality assurance comprises three types of procedures:
standard operating procedures;  procedures for finding and cor-
recting errors and inconsistencies;  and procedures for data
quality assessment (i.e.  degree of confidence that users can have
in the data).   As applied to emission inventories, these proce-
dures would focus more upon human error than upon equipment
parameters.  Guidelines for developing an emission inventory
quality assurance program would first analyze the system to
identify its components;  second, estimate the potential for error
and identify the errors having the greatest impact on inventory
results;  and third, develop techniques for the control and cor-
rection of errors.
     The components of the emission  inventory process are task
planning, data collection, technical  procedures,  and data re-
cording and reporting.  Descriptions  of these components follow:
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     0    Task planning  (a management function):  identifying
          working group responsibilities, establishing communica-
          tions, developing general inventory procedures, speci-
          fying data format requirements, and designing data
          files.
     0    Data collection  (an operations function):  identifying
          data requirements and sources, specifying formats,
          setting response schedules, and developing specific
          data collection mechanisms  (including continuous updat-
          ing) .
     0    Technical procedures  (an operations function):  all
          tasks related to data analysis and interpretation, and
          the calculation of emissions.
     0    Data recording and reporting  (a management and opera-
          tions function):  determining report formats and proce-
          dures for coding, editing and recording.
     Errors include inconsistencies in the data, as well as
mistakes.  Typical errors in the emission inventory process can
often be linked to more than one of the four components listed
above.   Examples of common errors are omitted or duplicated
emission sources,  incompatible time bases among sources, variable
emission calculations resulting from the misuse of emission
factors, incomplete codes, and improper or variable reporting
units.   To illustrate,  emission sources could be duplicated in or
omitted from the data base through misinterpretation of process
diagrams by individuals completing permit or emission inventory
data reporting forms.  Entire facilities have been duplicated in
emission inventory systems because of failure of agency personnel
to change identification data when a facility changes names.
Variable emissions estimates might appear in different invento-
ries involving similar types and sizes of sources, depending on
technical personnel interpretation of emission factors that are
given as a range instead of an an absolute number, to use another
illustration.
     The control techniques devised for the emission inventory
process can be classified as preventive or corrective.  Many of
the successful control techniques are already in use in various
agencies, and need only to be established on a formal basis.
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Formalizing these techniques provides the basis for a visible
quality assurance program.  It should make the agency staff more
aware of how their daily activities interface with a quality
assurance program, and it will provide a reference point for
management to assess the agency's needs for developing and imple-
menting further control procedures.  The techniques range from
training programs and spot check calculations to the establish-
ment of source accounting procedures and a separate coordinating
function to supervise and evaluate quality assurance within the
agency.
     Evaluation of the effectiveness of quality assurance com-
bines a quantitative assessment of the integrity of the data and
a qualitative assessment of the entire system.  A system audit,
to be performed by management, is a procedural review to deter-
mine whether the various elements in the program are being prop-
erly applied.
     Cooperation between EPA and state agencies would be essen-
tial for the implementation of quality assurance procedures.  The
major responsibility for program development and implementation
would lie at the state level,  but EPA could provide substantial
technical assistance based on its experience with ambient air
monitoring.  A pilot project could provide important cost-benefit
data and demonstrate the effect of the new procedures upon agency
organization.
     The procedures could be implemented on either a voluntary or
a regulatory basis.  Advantages and disadvantages are found in
both possibilities.  Voluntary implementation has the potential
to provide better resource allocations,  reduced resistance to
change, and greater management commitment to the program; but it
has not been entirely satisfactory when applied to ambient air
monitoring systems.  Regulatory implementation might be completed
more quickly and have a higher degree of cost-effectiveness; but
it might also place a burden on EPA, and might encounter more
implementation problems at the local level.
                               Vlll

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                            SECTION 1
                          INTRODUCTION

     The number of users interested in emission inventories has
been increasing since Prevention of Significant Deterioration
(PSD) requirements were adopted in the 1977 Amendments to the
Clean Air Act.  Industries that must include emissions and
source operating data with their permit applications to regula-
tory agencies will use the inventories to assess the relation of
PSD requirements and emission offsets to the possibilities for
industrial growth.  The evaluation of new energy strategies
relies upon emission inventories for a measure of the air quality
impact of burning various fossil fuels.  Emission inventories
will continue to be used in the traditional applications, such as
dispersion modeling for development and assessment of air quality
control strategies.  Determining reasonable further progress
toward attainment of national air quality standards is also a key
application for emission inventory data.
     Economic questions and concern about energy policies can be
expected to increase the use of the comprehensive emission inven-
tory data.  As more users realize the economic, health, and
social importance of the policies that are based on the data,
they will demand greater reliability.  A quality assurance pro-
gram applied to the production of emission inventories may im-
prove the reliability of the data and the compatibility among
inventories.
     This document reviews the emission inventory process and
suggests an approach to developing a quality assurance program
for it.  It includes a preliminary assessment of typical errors
and inconsistencies that occur in the emission inventory process,
and outlines procedures for controlling or minimizing them.  The
concept presented here is intended to be used as a basis for
                                1

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further discussions of quality assurance in the emission inven-
tory process.  The assessment of inventory problems is not com-
prehensive.  Additional problems undoubtedly remain to be iden-
tified.  However,  the discussion in this report does provide a
preliminary indication of the nature of the problems,  the impact
on the data,  and the feasibility of control.

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                            SECTION 2
                   QUALITY ASSURANCE ELEMENTS

2.1  DEFINITION OF QUALITY ASSURANCE
     Quality assurance is the system of procedures adopted by an
organization to ensure that its products or services meet speci-
fied standards of quality.  The procedures, which give confidence
that a basic level of precision and accuracy is maintained in the
product, include ones for standard operations, for finding and
correcting inconsistencies and errors, and for determining
product quality and reliability.
     A quality assurance program applied to emission inventory
procedures would have'three general types of procedures.  Stan-
dard operating procedures would include organization planning,
personnel training, project planning, and the development of
step-by-step procedures for technical tasks.  Techniques for
finding and correcting inconsistencies and errors would include
identification of potential error sources, evaluation of the
impact of these sources, location of checkpoints for optimal
problem detection, and a provision for timely response when
problems occur.  The determination of product quality and reli-
ability, in the context of an emission inventory, is the same as
data quality assessment.  These procedures include a periodic
(e.g. yearly) review of the entire inventory process, the devel-
opment of standards against which to test the accuracy and pre-
cision of results, and a system evaluation to maintain optimal
resource efficiency.
     A quality assurance program for-an ambient air monitoring
network is focused on physical parameters, such as pollutant
analyzers, monitoring sites, and calibration equipment.  The
emission inventory process, on the other hand, focuses on human

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factors (with the exception of computerized data processing).   As
a consequence, quality assurance for emission inventory applica-
tions might be weighted more heavily toward procedures analysis,
and the product quality might be more difficult to assess than in
an ambient air monitoring application.

2.2  DEVELOPMENT OF A QUALITY ASSURANCE PROGRAM
     Within an operating system, the first steps in developing
quality assurance procedures are to identify the components of
the system and to assess their relationship.   If structural pro-
blems are identified within the organization, it is useful to
reorganize or restructure the system or the emission inventory
procedures to correct these problems.  Potential sources of error
are analyzed to determine their effect on the system products.
Procedures already in use are reviewed to locate the key check-
points for critical potential errors.  Finally, different methods
for detecting the critical errors are explored, and a combination
of procedures is adopted that will detect the most errors with
the least resources.   Figure 2-1 summarizes this general approach
to the development of a quality assurance program.  In the fol-
lowing sections, this approach will be applied to the emission
inventory process.

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                          PERFORM SYSTEM ANALYSIS
                  IDENTIFY SYSTEM COMPONENTS AND PROCEDURES
                  EXPLAIN THEIR FUNCTIONS
                  DETERMINE PROCEDURAL INTERRELATIONSHIPS
                  DOCUMENT PROCEDURES AS FUNCTIONAL GROUPS
IMPLEMENT CORRECTIVE
PROCEDURES FOR SYSTEM
STRUCTURAL PROBLEMS
                                          I
                               QUANTIFY ERROR POTENTIAL
IDENTIFY STRUCTURAL WEAKNESSES
IDENTIFY ERROR SOURCES
QUANTIFY THE IMPACT OF ERRORS
PERFORM SENSITIVITY ANALYSIS
FLAG CRITICAL ERROR SOURCES
                         ESTABLISH CONTROL TECHNIQUES
                    DEVELOP ALTERNATIVE CONTROL  PROCEDURES
                    PERFORM COST-BENEFIT ANALYSIS
                    FORMALIZE AND DOCUMENT  PROCEDURES
         Figure 2-1.  Procedures for developing a
                quality assurance program.

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                            SECTION 3
           ANALYSIS OF THE EMISSION INVENTORY PROCESS

     The emission inventory process can be divided into four
major steps:
          0    Task planning
          0    Data collection
          0    Technical procedures
          0    Data recording and reporting
This division provides a convenient system for discussing inven-
tory procedures and problems, but in an actual application the
categories are interdependent.
     As Figure 3-1 shows, the process requires input from both
the management and operations levels.  The sequence of steps
begins with management input, progresses through tasks that are
primarily performed by operations,  and ends with input from both
management and operations.

3.1  TASK PLANNING
     Task planning includes a variety of procedures that reflect
agency policy and goals, and as a consequence require management
decisions.  The decisions address definitional,  organizational,
and technical problems.   Table 3-1  summarizes the procedures that
are included.

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     PRIMARY
      IHPUT
      GROUP
  MANAGEMENT
  OPERATIONS
  OPERATIONS
  OPERATIONS
  MANAGEMENT
   CATEGORY
                                      TASK PLANNING
                               -*•
                                     DATA COLLECTION
                                  TECHNICAL PROCEDURES
DATA RECORDING
      AND
   REPORTING
Figure  3-1.   Major steps  in the emission  inventory process

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  TABLE 3-1.  TASK PLANNING FOR THE EMISSION INVENTORY PROCESS

                          Definitional
                    Define objectives
                    Define requirements for meeting objectives

                         Organizational
                    Relate group functions
                    Assign responsibilities
                    Establish communications
                    Assign priorities
                    Budget resources
                    Document procedures

                            Technical
                    Develop job descriptions
                    Identify training requirements
                    Develop inventory techniques
                    Establish level-of-effort guidelines

     The definitional phase of the  task planning  step is the one
in which management defines the system objectives and outlines
the basis for meeting those objectives.
     0    Define objectives:   This  procedure requires management
          to assess the purpose(s)  of the emission inventory
          system.   Example goals may include providing informa-
          tion to other agencies, providing input to control
          strategy testing, providing data for assessing trends,
          or combinations of these  and other objectives.
     0    Define requirements for meeting objectives:  Once the
          major purposes of the emission inventory process have
          been identified, management needs to define the types
          of information required and to assign authority and
          responsibility for obtaining that information.  This
          includes defining specific data types and formats,
          determining possible or necessary interfaces with other

                                 8

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          functional systems within the organization, establish-
          ing the authority to obtain and disperse the necessary
          emissions data, and defining data'quality goals.
     The organizational procedures are those that determine the
total effort, the resources that will be expended, and the  rela-
tionship between the inventory process and other agency func-
tions.
     0    Relate group and agency functions;   This procedure in-
          cludes an organizational audit to define the purpose of
          each group within the organization and the level  of
          support that it can provide.
     0    Assign responsibilities;  This establishes the respon-
          sibilities and authority of the department or division
          for compiling and maintaining emission inventory  data.
          It is an early step in developing a mechanism for
          establishing the emissions inventory.   It might also
          include, for example, an assessment of the degrees of
          support that remote branch office operations can  pro-
          vide.
     0    Establish communications;  This determines the flow of
          information between management and operations levels
          within each department or division of  the agency.  It
          also establishes the environment for interdepartmental
          transfer of technical data.
     0    Assign priorities;  This function follows from the
          assessment by the agency of the scope  of its air  pol-
          lution problems, and the degree of industrialization or
          urbanization of the area within its jurisdiction.
     0    Budget resources;  This function is the logical exten-
          sion of the assignment of priorities.   Budget decisions
          reflect the expected impact of the emission inventory
          on agency effectiveness, and they affect the types of
          inventory procedures that will be adopted.

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          Document procedures;   This function is the formal sum-
          mary of the activities mentioned above.
     The technical procedures help to establish the degree of
confidence that can be placed in the emission inventory results.
They affect the precision and accuracy of the inventory,  and the
degree to which results can be  compared within or  among agencies.
These procedures are:
     0    Develop job descriptions;    This includes writing job
          descriptions for personnel who will be assigned ex-
          clusively to the emission  inventory process.
     0    Identify training requirements;   This identifies the
          technical questions that must be addressed in compiling
          an emission inventory,  and the functions requiring
          special skills or periodic updating of techniques.  The
          training programs and schedules will be  designed to aid
          in incorporating improved  inventory techniques  and to
          reduce confusion in performing inventory functions.
     0    Develop inventory techniques:   This includes  decisions
          about the emission factors to be used,  data gathering
          techniques, manual vs.  computer data processing, tech-
          niques to identify sources,  and workflow procedures
          within the organization.   These are only a few  examples
          of a range of complex functions.
     0    Establish level-of-effort  guidelines;  This is  directly
          related to the setting of  budget and task priorities
          that was described under organizational  considerations.
          It determines the kind of  data collection effort to be
          made and the comprehensiveness of the inventory.  It
          relies heavily on input from the definitional phase of
          task planning, i.e.,  management objectives, inventory
          quality goals, etc.
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The decisions made during task planning have a direct impact upon
the three other steps that have been outlined for the emission
inventory process:  data collection, technical procedures, and
data recording and reporting.

3.2  DATA COLLECTION
     Data collection involves significant levels of human inter-
action and attention to communication techniques.  The task can
be divided into procedures for compiling a new inventory, and
those for the routine maintenance of an existing one.  Table 3-2
summarizes the major procedures for each case, and brief descrip-
tions follow.  The procedures listed for compiling a new inven-
tory have many characteristics that easily could causs these
procedures to be characterized in the task planning phase of the
inventory process.  They are listed in the data collection phase,
however, because they are flexible depending on specific project
requirements.  The task planning procedures previously identi-
fied, however, provide more of an organizational basis for the
entire emission inventory program than for any specific applica-
tions that might occur within the program.
     TABLE 3-2.  DATA COLLECTION PROCEDURES IN THE EMISSIONS
                        INVENTORY PROCESS

                     Compiling an inventory
               Identify data requirements
               Identify sources and availability of data
               Determine reliability
               Specify formats
               Determine time constraints
               Determine the mechanics

                    Maintaining an inventory
               Estimate resource requirements
               Establish a schedule
               Determine the mechanics
     The procedures for compiling an inventory are:
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Identify data requirements:  This function (which is
directly affected by the priority and budgetary con-
straints imposed by the task planning phase)  determines
whether primary or secondary data sources are to be
used, the expected number and types of emission sources
to be inventoried, and the specific data elements
desired.
Identify sources and availability of data:  The range
of data sources will influence the decision to use
primary or secondary data.  Primary data sources in-
clude industrial or commercial facilities, and sec-
ondary sources include published data.  Primary sources
could also include other data bases, depending on how
they were compiled.  Data availability depends on state
and local regulations, confidentiality constraints, and
limitations of time and money.  In the case of primary
data, availability can be affected by the political
atmosphere between agencies and the managers  of a
facility.
Determine reliability:  The professional capabilities
and attitudes of the agencies or facilities supplying
either primary or secondary data must be judged.  Their
data collection techniques must be assessed,  as well as
the purpose for which the data have been compiled.
Specify data formats;  The formats for the inventory
will depend on its purpose and scope, and on  the mode
to be used to store and report the data.  If  the data
are collected as part of a formal regulatory  reporting
requirement,  they will have to conform to a specified
format.   Formats of data that are acquired must be
reviewed to determine the cost and time needed to make
conversions.   One of the most important elements in
selecting a format is units of measurement.
                     12

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      0    Determine  time  constraints;  These will usually be
          fixed by a reporting deadline  from a regulatory agency.
          The  lead time needed to collect primary data may not be
          compatible with the stated deadlines.  In these cases
          it may be  necessary to choose  between the quality or
          completeness of the data, and  project budget constraints.
          If the constraints are rigid,  the scope of the project
          may  need to be  changed.
      0    Determine  the mechanics:  This includes designing the
          questionnaire,  data recording  forms, and letters of
          request; and establishing procedures for tracking data
          through the emission inventory process.  These func-
          tions are  limited by the organizational decisions made
          during the task planning phase.
Each of these  considerations affects the completeness of the
inventory and  the quality of the data.
     The data  collection  procedures described above also apply to
the maintenance of an existing inventory.  In addition, there are
some procedures specific  to inventory maintenance that will
affect the suitability of the inventory  for future uses.  Three
major ones are described  below:
      0    Estimate resource requirements:  These requirements
          depend on  the comprehensiveness of the inventory to be
          maintained and  on the schedule for updating it.  Esti-
          mates are  based on data volume, frequency of updates,
          mode of update  (manual or computer), and number of
          personnel  to be assigned.  Each of these parameters is
          established during the task planning phase.
      0    Establish  a schedule:  Scheduling relies on the re-
          source requirements that are budgeted during the task
          planning phase.  Update frequency affects the way the
          data is maintained in the inventory file, and it also
          influences the  resource requirements for specific
                               13

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          applications.  A major problem with many data bases is
          that the sources use different time periods.  This
          variation can reduce the reliability of the data for
          strategy testing or other applications.
     0    Determine the mechanics:  Areas of concern in this
          category include system compatibility  (e.g., permit
          systems vs. emission inventory systems), resource
          availability, and interagency and intraagency com-
          munications.  The update procedures should strive for
          a common time base among emissions sources.  The update
          should be automatic, and should include editing and
          file checking procedures.  The mechanism must include a
          method to identify emission sources that have undergone
          significant changes, i.e.,  addition,  deletion, or
          changes in physical or operating parameters since the
          last update.

3.3  TECHNICAL PROCEDURES
     The third task category in the emission inventory process
comprises the technical procedures.  These procedures (see Table
3-3) include data analysis,  emissions calculations,  and some
important data flow and control techniques that directly affect
the use of the results.  The technical procedures, which can be
divided into technical and clerical functions,  are the ones most
often discussed in documents dealing with emission inventories;
and they have been the subject of numerous seminars and training
sessions.  This voluminous information about technical procedures,
however, does not make them any more important in terms of their
impact on inventory quality and data applications than the other
three categories.  These technical procedures are part of a con-
tinuing effort to assess and update emission inventory data as
well as the daily activities that are used to collect and report
the data.  The technical portion of this category involves
decisions about data input to the inventory process and the

                               14

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        TABLE 3-3.  TECHNICAL PROCEDURES IN THE EMISSION
                        INVENTORY PROCESS
                            Technical
                    Conduct training activities
                    Determine applicable emission factors
                    Prepare support materials
                    Calculate emissions
                    Review results
                            Clerical
                    Assemble reporting and calculation
                     forms
                    Develop system to assign source
                     identification numbers
                    Control work flow
preparation and review of emissions estimates.  Descriptions of
these functions are given below:
     0    Conduct training activites;  This function requires the
          participation of both management and technical staff.
          Training activities include both periodic, e.g. semi-
          annual or annual, seminars to update procedures and
          intermittent special sessions relating to specific
          problems.  Special sessions might be held, for example,
          to discuss requirements for a special inventory or
          update that may differ in some respects (data formats,
          detail required, etc.) from the routine agency inven-
          tory procedures.  Periodic training sessions might
          include discussions of new emission factors, procedural
          changes to eliminate specific operating problems or to
          interface with a new data reporting system, etc.
     0    Determine applicable emission factors;  This is a con-
          tinuing responsibility that should be assigned directly
          to a member of the emission inventory staff.  Duties
          include staying informed about changes in emission
                                                               \

                               15

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          factor technology,  and making decisions about when an
          agency should develop and apply its  own emission factors,
     0    Prepare support materials:   These materials are the
          illustrative calculations,  tables of codes, and appro-
          priate references for the technical  staff members who
          will work on the inventory.   Senior  technical staff act
          as advisors to junior staff  who are  preparing the
          emissions estimates,  but some questions can easily be
          answered without consulting  the senior staff.  Support
          materials also help to maintain consistency within the
          inventory.  This function is closely related to the
          training activities function.   Support materials change
          as inventory data gathering,  emission estimating, and
          data reporting techniques change within the system.
     0    Calculate emissions:   The success of this critical
          function has a direct relation to the amount of prep-
          aration that has been made,  through  the three functions
          described above.
     0    Review results:   This function entails spot checks of
          calculations;  of assumptions and engineering judgments;
          unit conversions;  and adherence to established proce-
          dures.  To accomplish this review, project or group
          managers need to set  guidelines about documenting tlhe
          assumptions and calculations that are made.  The fre-
          quency of these checks will  depend on the staff exper-
          tise,  size of the inventory,  etc.
     The clerical portion of  these procedures  comprises the
following recordkeeping functions:
     0    Assemble reporting  and calculation forms:  This in-
          cludes a review of  the format requirements for the data
          base to which the data will  be added.   The format for
          recording emissions estimates and associated inventory
          data must be consistent for  all emission sources.

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     0    Develop a system to assign source identification
          numbers:   The initial list of sources to be included in
          the inventory must be reviewed to see if it contains
          duplicate sources with different identification numbers,
          especially sources that have had name changes.  A
          control list of assigned identification numbers and
          their associated sources is established to avoid dupli-
          cate number assignments.  If data are taken from
          several data bases, a cross-reference must be estab-
          lished to prevent double counting of sources.  These
          cross-reference lists may also help to flag question-
          able cases,  such as sources that have had name changes
          or that should be deleted from one of the input files
          because they are no longer operating.
     0    Controlling work flow:  This is a technical planning
          procedure that routes the work through the data han-
          dling and review process and maintains an inventory of
          work that is in process or is complete.

3.4  DATA RECORDING AND REPORTING
     The procedures for data recording and reporting, summarized
in Table 3-4, apply to both manual and computer data handling
techniques.

   TABLE 3-4.  DATA RECORDING AND REPORTING PROCEDURES IN THE
                   EMISSIONS INVENTORY PROCESS

                    Determine format requirements
                    Develop coding and recording guidelines
                    Implement editing procedures
                    Implement data verification procedures

In an actual application,  many of these procedures become part of
the technical procedures.   They are discussed separately here
because many are closely related tasks, easily analyzed and
                               17

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controlled within the context  of  developing and  applying quality
assurance procedures.
     The data recording, and- reporting  functions  are described as
follows:
     0    Determine format requirements;   This requires a review
          of the system to which  the inventory results are to be
          added.  Important considerations include  the source
          identification system,  units of  measurement, special
          codes (such as control  and process  identification
          codes),  appropriate  field sizes, and implied or ex-
          plicit decimal requirements.  The final reporting de-
          sign is dictated by  the data base format  review.
     0    Develop coding and recording guidelines;   This follows
          directly from the development of format requirements.
          For computerized files, it includes specifications for
          field adjustment,  embedded blanks, decimals, alphabetic
          and numeric fields,  and definition of  terms  referenced
          on the coding forms.  A familiar example  is  the U.S.
          EPA guidelines for the  National  Emissions Data System
          (NEDS).   The NEDS system, the repository  for emissions
          data reported to EPA in compliance with the  Clean Air
          Act, is extensively  documented.  Seminars and training
          courses have been conducted  to teach data contributors
          at the agency and contractor level about  the specific
          coding requirements  of  this  system.  Similar specifi-
          cations can be developed for any system.
     0    Implement editing procedures:  A series of quality
          checks must be established to ensure that units specifi-
          cations and coding and  reporting requirements have been
          met.  Effective editing procedures also include checks
          for missing data,  improper codes, and  similar problems.
          The NEDS editing procedures  can  serve  as  a model for
          agencies developing  their own systems.  The  editing
          procedures provide a degree  of input to assessing

                               18

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system efficiency.  Editing statistics regarding number
and types of data recording problems can provide feed-
back to management to use in the continuing training
activity cycle.
Implement data verification procedures;  Routine proce-
dures must be established to verify the validity of
data submitted to the inventory system, to correct
errors flagged during data review and editing, and to
obtain data elements that are missing from the file.
As an example, a state agency might routinely (e.g.
semiannually) summarize missing or questionable data
elements and request the responsible facilities to
respond by supplying new or corrected data.  In addi-
tion, it might be useful for an agency to recap the
facilities, sources, and key data parameters repre-
sented in the inventory file and ask the data origi-
nators to briefly review and reconfirm or change the
data if necessary.  This type of verification procedure
could instill more confidence on the part of data users
in the inventory file, result in a better working rela-
tionship between agencies and facilities in their
jurisdiction, and result in more current data than
might be available if the inventory relied on informa-
tion directly from a permitting system, which typically
might be on a 3 to 5 year cycle.  Appendix B provides
an  overview of the types of editing and verification
procedures used at NADB.  These procedures can serve as
a model for this phase of an emission inventory quality
assurance program.
                     19

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                            SECTION 4
        ERROR POTENTIAL IN THE EMISSION INVENTORY PROCESS

     An assessment of the potential for error in emission inven-
tories provides a clear demonstration of the need for quality
assurance procedures.  Each category that was outlined in the
analysis in the preceding section has an impact upon the total
potential for error.  The task in this section is to identify the
types of errors and their sources,  and to estimate their im-
portance in affecting inventory reliability.  In the context of
this discussion, the term "error" means not only wrong answers
(e.g. incorrect calculations), but also inconsistencies among
emission inventory results (e.g.  cutoffs for facility size).
Both problems are equally important, because they can lead inven-
tory data users to wrong conclusions, and can prevent the results
from being useful for comparisons within or among states or
regions for the purpose of assessing control programs.
     Most of the problems that occur during the inventory process
can be directly related to one or more of the four task cate-
gories:  task planning, data collection, technical procedures,
and data recording and reporting.  These relationships become
especially important for establishing the controls that might be
used in a quality assurance program.

4.1  TYPICAL ERRORS
     The errors and inconsistencies that are discussed here are
among the most obvious that can happen during the inventory
process.  Five errors have been chosen for discussion.  The list
is not exhaustive, however:  it is only meant to illustrate the
types of problems that can occur, their impact,  and control
techniques that can be applied in a quality assurance program.

                               20

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The causes of the errors are poor planning, constraints in the
state of the art of inventory techniques, and random human error.
Each error will require a different control.  The development of
a quality assurance program for emission inventories will require
an analysis similar to but more comprehensive than is possible
here, including sensitivity testing where applicable.
4.1.1  Missing or Duplicate Emission Sources
     It is possible for sources to be inadvertently missed or
double counted in the emission inventory.  This error would not
be expected to be critical for smaller sources, but could be so
for large ones (depending on land use patterns).  The problem
could result from poor bookkeeping or inadequate procedures for
reviewing data from major facilities.  Quantifying the error
potential for this problem may only be useful in a subjective
context.
     If emissions sources are missing from the inventory,  the
cost could be the adoption of relaxed controls that could have a
negative impact on local health and welfare.  If emissions sources
are duplicated,  the cost could be the adoption of controls that
are too strict and that could restrain industrial competition or
retard area growth.
4.1.2  Errors in Locating Sources
     The location of a facility or emission source can be referred
to by address,  by UTM coordinates, or by latitude-longitude
coordinates.   Errors in coding the location could have a sig-
nificant effect on dispersion modeling results, and could intro-
duce bias into the evaluation of control strategies.   The error
could result from misreading maps, from reporting the coordinates
of an administrative office instead of the emission source, or
from transposing digits during data recording.
     An-example of an extreme error in recording UTM coordinates
was discovered during a dispersion modeling application.  The
data had been taken directly from a state agency emission
                               21

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inventory file.  For one TSP source (25 tons emitted per year),
the coordinates were recorded as 320.7, 596.4; they should have
been 320'.'f, 4596.4.  In other words, the emission source was
represented in the file as being 4000 kilometers away from its
real location.  Admittedly, this was a gross error that probably
resulted from improper coding of a computer load sheet or a
keypunch error.  The impact on modeling results of this type of
error would depend both on its magnitude and on the size of the
associated point source.
     The cost of an error in coding a location might include the
time required to trace the problem, additional computer runs
during the modeling process, impact on project schedules, and the
time for checking other coordinates in the file.  In the example
given, other coordinate errors were found that were not as great.
Errors of this type,  however, were numerous enough to cause the
user to doubt the validity of all the coordinates in the file.
This problem could have been avoided and the potential costs
reduced if routine procedures had been introduced into the in-
ventory process to verify this critical data element.
4.1.3  Divergent Time Frames
     Most emission inventory systems are linked in some way to
operating permit systems.  Operating permits are generally issued
for more than one year, and the year of maturity depends on the
year of issue.  As a consequence, the data in the permit system
and in the inventory system that uses it represent different
years for different sources at any one time.  In other words, the.
inventory update procedure never allows the system to catch up
with itself so that all emission sources can be represented for
the same time period.  The problem may be compounded if a sizable
lag exists between the times the permit system data and .inventory
file are updated.  In these circumstances, data in the inventory
file may not represent current source conditions, especially if
the source technology has changed or if economic and business
                               22

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cycles have  forced major changes in operating schedules since the
time the permit was  issued.
     One county chosen at random from an emission inventory file
showed the following percentages of total TSP potential emissions
for each year  of record:
                     1978       0 percent
                     1977      67 percent
                     1976      13 percent
                     1975      10 percent
                     1974      '10 percent
If modeling  were performed to represent the year 1977, at least
33 percent of  the data in the file would first need to be updated.
If modeling  were desired for years in the past, the effort would
depend on whether the agency maintained historic records.
     The problem of variable time frames could be alleviated, but
not entirely solved, by verifying or adjusting the data in interim
years.  To reduce the cost to both industry and agency, the
adjustment could be operated on an exception approach; that is,
plant management would be asked to comment only on changes that
had occurred since the permit was issued.
     The cost  of this problem would be expressed in terms of the
resources needed to update the inventory as a supplement to the
normal permit  procedures.  The frequency with which data from the
same year are  needed would influence the decision to perform up-
dates.  Costs  could well outweigh benefits, in this as in other
applications.
4.1.4  Emission Factor Reliability
     Depending on how they are derived, emission factors vary
considerably in their precision and accuracy.  The EPA has
assigned reliability ratings to its published emission factors,
with a low rating denoting a factor derived from information too
poor to allow  its use with a high degree of confidence.  In this

                               23

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case, an agency might justifiably decide to develop its own
factor.  Because this would be a subjective judgment, it would
best be handled by a joint agreement between EPA and the agency.
     Some of the factors that have been published show a range,
and an industry or an agency could select either end of the range
to prepare its emissions estimates.  Although little evidence
could be given to support either value, the difference in esti-
mates would be significant.  For example, the range of hydro-
carbon emissions from the combustion of wood and bark wastes in
                                          *
boilers is listed in Supplement 7 of AP-42  as 1 to 35 kg/MT (2
to 70 Ib/ton).  A footnote instructs users to apply the lower
value for boilers that are well designed and operated, but an
inept technician could fail to read the footnote and decide to
apply the average at 17 kg/MT.
     These problems with emission factors might be alleviated by
increased efforts at EPA to improve questionable factors,  or by
agency decisions to develop their own factors in such cases.
Either approach is costly and time consuming.   The EPA is con-
tinually involved with the development and analysis of emission
factors,  and an expanded effort may not be cost-effective.   An
in-depth study would be needed before proposing such a solution.
Agencies concerned with quality assurance in the emission in-
ventory process should carefully review the effect of emission
factors on agency policy and,  ultimately, on industry and the
economy.
4.1.5  Calculation Errors
     Errors in calculations can occur as a result of transposing
digits,  entering the wrong numbers in a calculator,  or misinter-
preting either the emission factors or the instructions for their
application.   The sulfur dioxide emission factor for oil combus-
tion in a power plant illustrates the typical  range of error.
*
  Compilation of Air Pollutant Emission Factors.   2nd edition.
  U.S.  Environmental Protection Agency.  AP-42,  February 1976.
                               24

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The factor is  19 kg/10  liters of oil burned.  The number could
conceivably be entered as 91, which would increase the estimated
emissions by a factor of 4.8.  This kind of error is random, and
the only preventive measure available is to emphasize to staff
members the importance of being careful in their calculations.
Calculation errors could be detected through a spot check, or
through a systematic review of emissions vs. throughput.  The
latter technique, which could be either manual or computerized,
would detect gross discrepencies.
4.1.6  Characterizing Errors
     The errors discussed above were chosen because they repre-
sent a variety of problems that have an impact on an emission
inventory, and have a variety of causes and potential solutions.
The impact of errors on inventory results can best be assessed
through a comprehensive sensitivity analysis of each type of
error.  This major task would require substantially more re-
sources than are available for this report.
     It is possible here,  however, to characterize the potential
causes of the common errors and to suggest techniques for their
control.  This characterization can provide a basis for a more
thorough analysis that might be performed in the future.
     Table 4-1 summarizes several types of errors that can occur
in the emission inventory process.  This summary also shows the
potential causes of these errors and the procedural category to
which each is related.   Although only 10 error types are listed
in the table, a total of 34 potential reasons for these errors
have been suggested.   This indicates that multiple problems in
the inventory process,  often related to more than one procedural
category, can result in the same types of errors in the inven-
tory.   The error sources,  then, rather than the errors them-
selves, are the key for developing control techniques.
                               25

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            TABLE 4-1.  ERRORS AND ERROR  SOURCES  IN  THE  EMISSION  INVENTORY  PROCESS
      Error
     Potential sources
       Related
 procedure category
(Ti
   Missing facilities or
   sources
   Duplicate  facilities or
   sources
   Missing operating or
   technical data
   Erroneous technical  data
   Improper  facility  location
   data
Permit and inventory systems out
of phase; errors in estimating
potential emissions; lost paper-
work; problems with computer file
updates

Name changes through corporate
acquisitions; use of multiple
data sources with different
source numbering schemes

Ambiguous data request forms;
intentional deletion by facility
staff; inadequate followup pro-
cedures; inadequate project
control, i.e., no tentative indi-
cation of inventory size

Misinterpretation of data request
instructions; assumed units,
faulty conversions, etc.; inten-
tional misrepresentation by the
facility; poor handwriting

Recording coordinates of facility
headquarters instead of the
operating facility; inability of
technicians to read maps; changes
in UTM zones
 All categories
Data collection
Data collection, task
planning
Data collection
 Data collection, tech-
 nical procedures
    (continued)

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TABLE 4-1  (continued)
   Error
     Potential sources
      Related
procedure category
Inconsistent area source
categories or point source
sizes

Inaccurate or outdated
data
Errors in calculations
Errors in emission esti-
mates
Reported emissions wrong
by orders of magnitude
Failure to designate inventory cut-
offs


Mixed use of primary and
secondary data without a stan-
dard policy

Transposition of digits; decimal
errors; entering wrong numbers on
a calculator; misinterpreting
emission factor applications

Imprecise emission factors;
applying the wrong emission factor;
errors in throughput estimates;
improper interpretation of com-
bined sources; errors in unit con-
versions; faulty assumptions about
control device efficiency; ranges
of sulfur/ash contents in fuels

Recording the wrong SCC code for
subsequent computer emission
calculations; ignoring implied
decimals.on computer coding sheets;
transposition errors; data coding
field adjustment
Task planning
Task planning
Technical procedures
Technical procedures
Data recording and
reporting

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4.2  CONTROL TECHNIQUES
     The development of an effective quality assurance program
rests upon a sound assessment of system procedures and identifi-
cation of potential sources of error.  Techniques for controlling
errors are as important as those for detecting them.
     Techniques for error control can be classified as preventive
or corrective.  Preventive techniques are those that are applied
as part of the task planning procedures.  Classroom instruction,
for example, is a preventive technique, since it flags typical
problems for those participating in the inventory process and
offers ways to avoid them.  Table 4-2 lists examples of preven-
tive quality assurance techniques.   These techniques are listed
as they might apply to the four major categories of emission
inventory procedures.   The types of problems shown in the table
are those that might be prevented with each technique.  Many of
these techniques are already in use,  but they have not been
formally established.   In fact,  several were previously listed as
part of the normal operating procedures in the emission inventory
process.  This suggests that many of the control techniques might
be implemented with few changes in normal agency procedures.
     Corrective control techniques are those that are implemented
to detect errors that  cannot be controlled by the preventive
measures.  These techniques,  some of which are listed in Table
4-3, reduce random errors such as digit transposition.  Their
primary purpose, however, is to detect deficiencies in the emis-
sion inventory process.  The techniques can provide useful feed-
back to the task planning stage and can provide a basis for
improving the preventive control techniques.  Spot checks of
coding forms or calculations is an example of a corrective con-
trol technique.  When  developing the emission inventory quality
assurance system,  the  control techniques related to the most
critical types of errors must be given priority.
                               28

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             TABLE  4-2.   EXAMPLES  OF  PREVENTIVE QUALITY ASSURANCE TECHNIQUES
                 Procedure  category
ro
vo
                 Task  planning
                 Data collection
                 Technical  procedures
                 Data recording  and  re-
                 porting
     Control techniques
Training programs,  certifica-
tion
                                        Establish position for a quality
                                        assurance  (QA) coordinator
Edit data request forms




Data review by local agencies


Visits to largest polluters



List current source ID

Orientation sessions
                                        Develop reference
                                        materials
Assign technical staff
specifically for codinq
data
Problems controlled
Misapplication of emission
factors;  incorrect units and
codes;  misinterpretation of
source data

Outdated inventory techniques;
inappropriate emission factors;
ineffective control techniques;
overcontrol in the QA program;
QA program not in phase with
inventory procedures

Burdensome forms resulting  in
data collection delays or non-
compliance; inconsistent
reporting units, etc.

Erroneous source data reported,
missing sources

Missing sources, significant
volume of county emissions  un-
confirmed

Duplicate or missing sources

Misunderstandings in approach
or systematic errors found
with corrective controls

Unfamiliarity with processes,
emission factors, codes,  units,
etc.

Inconsistent coding, field
adjustments, etc.

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                 TABLE 4-3.   EXAMPLES OF CORRECTIVE  QUALITY  ASSURANCE  TECHNIQUES
                 Procedure category
                 Task planning
                 Data collection
Id
O
                 Technical procedures
                 Data  recording and report
                 ing
Control techniques
Annual system audits
Local agency review of com-
pleted inventory data
                                            Review years of record at
                                            local agency level
Engineering review of major
facilities

Spot check calculations
Check total facility or
emissions against historical
inventory data

Edit computer data
Problems controlled
QA procedures not  costeffec-
tive,  QA procedures  inappro-
priate for updated inventory
techniques

Missing or duplicate sources,
inappropriate source controls,
improperly combined  sources

Inconsistent time  representa-
tion among sources.   Interim
operating changes  not re-
flected in permit  or inven-
tory files

Data or process misinterpreta-
tion

Improper reporting units,
random calculation errors,
systematic calculation errors
related to inadequate training
or information

Inconsistent inventory tech-
niques or data sources
Coding errors,  e.g.,  improper
source codes,  unreasonable
emissions vs.  throughput,
field adjustment,  embedded
blanks

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     The system audit is a control technique that is principally
a management task.  It entails a periodic, complete review of the
quality assurance system.  The auditor looks at current proce-
dures and their effectiveness, assesses the adequacy of inventory
procedures to maintain state-of-the-art technology, and takes
steps to see that the quality assurance system changes according-
ly.  The emission inventory system should include a mechanism for
user feedback.  Both data users and data contributors must be
able to communicate with management regarding problems they are
having applying or preparing data.  Information regarding data
preparation problems that occur at the data source could result
in revised data format or reporting requirements that could
expedite data preparation.  Information regarding the applica-
bility of data for specific uses could result in improved emis-
sion factors, improved data summary formats, retrieval options,
etc.
                               31

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                            SECTION 5
            IMPLEMENTING QUALITY ASSURANCE PROCEDURES

     Developing a program and publishing guidelines are only the
first steps in implementing an effective quality assurance pro-
gram for emission inventories.  Informing agencies of the advan-
tages of the program,  and assisting them in adapting to it, are
equally important.  The examples presented in other sections of
this document provide  a starting point for that orientation.
Even if agencies are convinced that quality assurance programs
are important, two significant problems could impair successful
implementation:  resistance to organizational change, and budget
constraints.  These problems are encountered during any major
procedural change, and are not unique  to quality assurance.
     A pilot project might reduce the  resistance that stems from
the pertreived "impact of quality assurance procedures on the
routine operation of the agency.  The  EPA would•develop a quality
assurance program and  implement it in  a typical agency, an ap-
proach having two important advantages.  The first is the mech-
anism the pilot project would provide  for debugging the system.
It is much easier to develop procedures on paper than to imple-
ment them to the satisfaction of the users.  Experience in
implementing quality assurance programs for ambient air moni-
toring, for example, shows that one format does not apply to all
organizations.  Changes in report forms and in the sequence or
timing of procedures must be flexible  enough to allow the program
to be absorbed into the total monitoring procedures, rather than
altering the total monitoring structure to conform to the quality
assurance program.  Practical flexibility should be a recognized
requirement in a quality assurance system for emission inventories.
                               32

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     The  second advantage the pilot project offers is the real
cost data  it could yield.  The potential drain on agency re-
sources is an objection often made to adopting quality assurance
procedures in ambient air monitoring or laboratory systems.  A
pilot project could provide a baseline for estimating the cost of
various tasks in the program, and it could provide empirical data
to support cost-benefit analyses.  Because of the health, welfare,
and economic implications of the emission inventory data, cost
must be discussed in relation to the benefits of a quality assur-
ance program:  it is not reasonable to preclude better controls
based on cost alone.  A pilot project, in conjunction with a
cost-benefit analysis, might sort out the essential elements of a
quality assurance program from those that can be implemented
gradually.

5.1  THE ROLE OF FEDERAL GUIDANCE.IN QUALITY ASSURANCE DEVELOP-
     MENT AND IMPLEMENTATION
     The EPA is in the best position to develop a basic quality
assurance program for emission inventories.  Leadership by EPA
could prevent duplication of effort by state and local agencies,
and could provide an opportunity for those agencies to apply the
resources that would normally be used for program development
toward implementation and operation.   In ambient air monitoring
systems, the implementation phase has been shown to take a large
share of the resources for the quality assurance program; and the
same situation will probably apply to the programs for emission
inventories.  The implementation phase would be the major respon-
sibility of the state agencies.
     Besides avoiding duplication of effort, the role of EPA in
program development would provide the consistency needed for a
basic level of confidence in the emission inventories compiled by
different agencies.  The minimum standards for quality assurance
would include, conceptually, those elements identified in the
system and sensitivity analyses as being most critical to the
accuracy and precision of inventory data.  The size and types of
                               33

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sources, frequency of update,  specifications of the data sources,
data validation procedures,  procedures for developing non-EPA
emission factors, and similar  considerations would be covered by
the basic program.  Other elements—the format for internal
agency procedures, reporting formats,  organization structure--
might be suggested, but the  agencies would be able to tailor them
to their own organizational  constraints.   Implementation of ele-
ments beyond the base level  would be optional, and would repre-
sent a fine tuning of the quality assurance program.
     The specific responsibilities of the EPA in developing the
basic program would include  the following:
     0    Perform a complete system analysis:  This analysis of
          the emission inventory process would be similar to, but
          more comprehensive than, the analysis in this document.
          It would include a complete list of the errors and
          inconsistencies in an inventory as well as a sensi-
          tivity analysis of each error type.
     0    Develop step-by-step procedures:  This task would
          include an outline of the inventory procedures and
          identification of  the specific quality checks asso-
          ciated with each.   Instructions would be given for
          decisions On frequency of quality checks and procedures
          for error correction.  The step-by-step procedures
          would be developed for each of the specific procedural
          categories of the  inventory process:  task planning,
          data collection, technical procedures, and data re-
          cording and reporting.
     0    Develop guidelines for resource requirements:  The
          guidelines would provide planning support for agency
          management during  the implementation phase.
     These three basic tasks would lay the groundwork for a basic
program in any agency, even  though the specific details of each
program may vary according to organizational activities and
resources.  Appendix A is an example of .an outline of a quality
assurance program, which can be used as a starting point or
checklist for the development and implementation of a prototype•.
program.
                               34

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5.2  REGULATORY VERSUS VOLUNTARY APPROACH
     Quality assurance programs for emission inventories can be
implemented on a national basis either voluntarily or by regula-
tion.  Experience with quality assurance programs in ambient air
monitoring systems can provide insight about the best approach to
use.
     Guidelines for quality assurance in ambient air monitoring
systems have been available through the EPA for 4 to 5 years.
These guidelines are pollutant-specific, and this characteristic
could probably be cited as contributing to delays in implementing
them among various states.  In addition to the pollutant-specific
guidelines, a general guideline to be used by agencies as a
reference for developing and implementing quality assurance
procedures was published in 1975,  after the initial v;rsions of
the pollutant-specific guidelines had been issued.  The overview
was a discussion of the elements of a quality assurance program,
but it did not include specific procedures for development and
implementation.  It is possible that specific implementation
procedures may have speeded the implementation process among the
states.
     For whatever reasons—problems in conceptualizing the ap-
proach to implementation, budget constraints, organizational
resistance to change, differing agency priorities — the states
adopted the procedures at various rates.  Some states have ap-
parently still not documented formal quality assurance programs
for ambient air monitoring.
     The EPA used the voluntary approach for establishing
quality assurance in ambient air monitoring.  Implementation lags
among states have prevented the direct comparison of data across
geographic areas, and have caused EPA to be concerned about the
value of selected air quality data.  The concern about data
quality has resulted in the inclusion of mandatory quality
                               35

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 assurance  procedures  in  the proposed regulatory revisions  for air
                                        *
 quality  surveillance  and data reporting.

	Tfre 'voluntary appTreraefr feo> implementation- has potential

 advantages:

     0     The  opportunity for phased implementation by  allowing
           agencies  to implement nonessential but desired elements
           as resources allow.

     0     Reduced resistance to change an'd- improved cooperation
           by fostering the feeling of mutual agreement  and
           realization of mutual benefits.

     0     Greater management commitment through agreement  rather
           than compliance.

 Potential  disadvantages  include:

     0     Inconsistencies in procedures and data quality result-
           ing  from  different agency priorities.

     0 .    Duplication of efforts in developing the basic program,
           especially  if  state agencies elect to replace the
           recommended EPA guidelines with  their own.

     0     Lack of control of basic program elements by  EPA.

     0     Variable  schedules for implementation depending  on
           resource  availability and agency interests.

     If  EPA decides to adopt the voluntary approach, a  critical

 review of  the  ambient air monitoring experience would be useful

 to  identify problems  and to prevent them from occurring in the

 emission inventories.

     The regulatory approach has the following potential advan-

 tages:

     0     More rapid  implementation and, consequently,  an  earlier
           assurance of data quality for nationwide comparisons.

     0     A logical tradeoff in the regulations, by reducing  the
           semiannual  reporting requirement to an annual reporting
           requirement (as mentioned, in the proposed regulatory
           revisions).
    "EPA's Proposed Regulatory Revisions for Air Quality Surveil-
    lance Data Reporting," 43 CFR 34892, August 7, 1978.

                               36

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      0    Cost savings in PSD and  strategy testing and related
          applications by eliminating the need for special pur-
          pose inventory updates.
Potential disadvantages include:
      0    An  increased burden on the EPA to provide timely guide-
          lines and implementation assistance.
      0    The possibility of developing programs that are less
          than adequate because of shortened review procedures or
          inadequate planning.
      0    Organizational resistance to regulatory approaches as
          they impinge on state agency autonomy.
      If EPA decides to adopt the regulatory approach, the re-
quirements must be cost-effective and flexible enough not to
place undue strain on state agencies that might have irore sig-
nificant problems to contend with than their emission inven-
tories.
     The most utility with the fewest implementation problems
might be realized through the voluntary approach.  Maximum cost-
effectiveness, on the other hand, might be realized through the
regulatory approach.  The cost-effectiveness would come primarily
from eliminating the need for agencies or industries to conduct
separate inventories,  either point source or area source.  More-
over, the increased accuracy and precision of the data, and the
consistency of the time base represented in the inventory, should
provide greater reliability in the decisions made with the in-
ventory data.  These decisions and environmental policies have a
significant effect on the health, welfare, and economy of the
region where they are applied.
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            APPENDIX A

EXAMPLE OF A FORMAT FOR AN EMISSION
INVENTORY QUALITY ASSURANCE PROGRAM
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1.0  Quality Assurance Policy Statement

     1.1  Purpose of the program
     1.2  Scope

2.0  Summary

     2.1  Organization chart
     2.2  Emission inventory tasks and assignments of responsibility
     2.3  Information flow
     2.4  Summary of control techniques and relation to informa-
          tion flow
     2.5  Audit procedures

3.0  Technical

     3.1  Task Planning

          3.1.1  Training and staff qualification
          3.1.2  Schedule and frequency of updates
          3.1.3  Quality assurance coordinator - duties and
                 responsibilities
          3.1.4  Data sources

     3.2  Data collection

          3.2.1  Forms and procedures
          3.2.2  Data review
          3.2.3  Quality assurance controls

     3.3  Technical procedures

          3.3.1  Emission factors
          3.3.2  Data flow
          3.3.3  Handling questions and problems
          3.3.4  Review procedures

     3.4  Data recording and reporting

          3.4.1  Recording and coding forms
          3.4.2  Rules for data coding
          3.4.3  Data editing procedures

4.0  System Audits

     4.1  Audit responsibility and schedules
     4.2  Procedures

          4.2.1  Elements
          4.2.2  Schedule
          4.2.3  Audit report
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1.0  QUALITY ASSURANCE POLICY STATEMENT
     The policy statement is the formal declaration of agency
commitment to developing and maintaining a quality assurance pro-
gram.  The policy statement defines quality assurance as related
to agency activities, explains the need for the program, and
provides the basis for committing resources to the program.

2.0  SUMMARY
     The quality assurance program summary is an executive sum-
mary of the technical procedures.  It provides an overview of the
major components of the program without explaining the details of
daily operating procedures.  The summary explains the flow of
emission inventory data through the agency, shows graphically the
interaction among functional groups, and flags the points in the
inventory procedures where quality assurance techniques are
applied.  It lists the control techniques and the frequency of
their application.  All quality assurance reporting forms, data
collection forms, computerized data coding forms, etc., are
included in the executive summary.

3.0  TECHNICAL
     The technical procedures include the operating details of
each of the four major emission inventory task categories.  This
segment of the quality assurance program documentation must
include step-by-step procedures for routine operations as well as
details of checking procedures.  The section on emission factors,
for example, must include all current factors to be applied and
must document the source of each.  The documentation of these, as
well as all other elements of the program, should be in looseleaf
notebook form to allow the documentation to be changed easily>as
procedures are changed.  This is an important point, because an
effective quality assurance plan is flexible and subject to
change.
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4.0  SYSTEM AUDITS
     This segment of the plan outlines the procedures for manage-
ment to follow in reviewing the effectiveness of the program.
The documentation specifies the records and procedures that will
be reviewed and the frequency of review.  It provides guidelines
for management to use in assessing the program, and it specifies
a management report format that can be used to compare audit
results over time.  The system audit is important, because it can
flag procedures that are not cost-effective, or, on the other
hand, it can indicate the need for more procedures to improve
data quality.
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         APPENDIX  B

OVERVIEW DESCRIPTION  OF NEDS
QUALITY ASSURANCE  PROCEDURES
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     The National Emissions Data System  (NEDS), maintained by
EPA's National Air Data Branch  (NADB), incorporates several
features of an emission inventory quality assurance program.
These program elements are concerned with editing and validating
data that have been reported to EPA from state air pollution
control agencies.  Although these procedures do not constitute a
total emission inventory quality assurance program, they provide
a good model for developing the data reporting portion of such a
program.  Figure B-l illustrates the data flow through the data
auditing procedure that has been adopted for NEDS.  Note that the
system provides for continual communications among data origina-
tors (state agencies),  data collectors (EPA regions and NADB),
and data users (industry, government agencies, etc).
     The important features of the data audit system are pre-
edit, edit, and validation procedures based on computer analysis
to flag data problems or to identify data anomalies prior to
entering data into the NEDS data base.  The first step in the
audit process is the pre-edit procedure,  which is performed by
the regional offices.  The pre-edit program sorts the data sub-
mitted by the state agencies and examines each record for gross
errors such as missing year of record or illegal transaction
codes.   A summary of incoming data,  including the number of each
transaction type in the data batch,  is produced for data control
purposes.
     After the pre-edit data problems have been corrected, the
regional offices run the data against an edit program.  The edit
identifies and rejects data records that do not meet minimum
criteria for updating the NEDS files.  Necessary corrections are
either made by the regional office or referred to the originating
state agency.  Records that pass the edit are forwarded to NADB
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    STATE AGENCY
               RtOIONAUOFFICE
                                                  USERS
 START,
  Figure B-l.   Data  flow through AEROS data auditing system*
Volume II, AEROS User's Manual Section 7.0.1, AEROS Data Auditing
System, U.S. Environmental  Protection Agency, Research Triangle
Park, North Carolina,  EPA-450/2-76-029, December,  1976.


                              44

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for further processing.  The edit program produces a summary
report of edit diagnostics showing the specific problems with
each data record requiring corrective action.  The edit diagnos-
tics are oriented primarily toward insuring that key data ele-
ments for further record processing  (i.e. estimating and reporting
emissions) are present and that key processing codes are valid
(e.g. emission estimation method codes, SCC codes, etc.).  Exam-
ples of NEDS edit diagnostic checks include:
     0    checking for valid control equipment codes
     0    checking for valid SCC codes
     0    checking for valid card action codes (e.g. a "delete"
          transaction code is valid only for cards 1,2, and 6 for
          point sources)
     0    checking for maximum parameter values (e.g. bituminous
          coal maximum ash content is 25 percent)
The edit program includes 35 diagnostics.
     NADB runs the edited data received from the regional offices
against a post-edit program similar to the pre-edit run at the
regional offices.  Problems flagged during the post-edit run are
referred to the regional office.
     Data that pass the post-edit are run against NADB's update
program to update the master file.  Validation reports are gen-
erated during the file update procedure.  The validation reports
identify suspect data, and it becomes the responsibility of the
regional offices to correct or verify those data.   Validation
checks performed during the update procedure subject the data to
more indepth analysis than the edit procedure at the regional
office level.  The update checks are oriented toward internal
data relationship validity.  Examples of the types of validity
checks that occur during the NADB update are:
     0    reasonable range checks for key parameter values, e.g.
          checking to see that the control device efficiency is
          reasonable for the indicated control device        	 —
     0    checks for completeness of data, e.g. ascertaining that
          specific SCC codes are included for specific emission
          sources within a facility.

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     0    .check  for reasonableness  of .parameters combinations,
          e.g. .determining that 'SIC and  SCC codes are compatible
     •Questions from $a.ta -users regarding pos-sibl'e data .anomalies
are directed to  NADB.  NADB  in turn prepares a memorandum for
action by the regional office, which may or may not require input
from the state agency from which -the questionable .data were
.originally reported..  Questions regarding data completeness are
handled simila-rl.y to questions regarding -validity.
                                 46

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                              TECHNICAL REPORT DATA
                        (Please read /nsiructions on the reverse before completing)
1. REPORT NO.
                          2.
                                                   3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
   Development of an Emission Inventory
   Quality Assurance Program
5. REPORT DATE
 	June 1979
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)

   David W. Armentrout
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
   PEDCo Environmental, Inc.
   11499 Chester Road
   Cincinnati,  Ohio   45246
                                                   10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.

  68-02-2585   T.O. 8
12. SPONSORING AGENCY NAME AND ADDRESS
  U.S.  Environmental Protection Agency
  Office of Air  Quality Planning & Standards
  Research Triangle Park, North Carolina  27711
                                                   13. TYPE OF REPORT AND PERIOD COVERED
                                                        FINAL
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES

  EPA  Project Officer:  James  H.  Southerland
16. ABSTRACT
  This  report discusses quality  assurance in  general and quality
  assurance related  to emission  inventories specifically.   The
  inventory process  is discussed in terms of  its procedural elements
  Typical error  types and remedies are discussed.   A suggested
  approach for developing a quality assurance program for  emission
  inventories is  giver..
                           KEY WORDS AND DOCUMENT ANALYSIS
                DESCRIPTORS
                                        b.IDENTIFIERS/OPEN ENDED TERMS  C. COSATI Field'Group
  Quality Assurance
  Emission Inventories
18. DISTRIBUTION STATEMENT
                                        19. SECURITY CLASS (This Report!
                                        Unclassified
            21. NO. OF PAGES

              46
                                        20. SECURITY CLASS (This page I
                                        Unclassified
                                                               22. PRICE
EPA Form 2220-1 (9-73)

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