svEPA
            United States
            Environmental Protection
            Agency
           Office of Air Quality
           Planning and Standards
           Research Triangle Park NC 27711
EPA-450/4-81-026a
September 1981
            Air
Procedures for Emission
Inventory Preparation

Volume I:  Emission
Inventory Fundamentals

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                                 NOTICE
     The Procedures for Emission Inventory Preparation consists of these
five volumes.

          Volume I   - Emission Inventory Fundamentals
          Volume II  - Point Sources
          Volume III - Area Sources
          Volume IV  - Mobile Sources
          Volume V   - Bibliography

     They are intended to present emission inventory procedures and
techniques applicable in State and local air programs, and for con-
tractors and other selected users.  The object is to provide the best
available and "state of the art" information.   For some areas, however,
the available source information and data either may allow more precise
procedures and more accurate estimation of emissions or may not be amen-
able to the use of these procedures.  Therefore, the user is asked to
share his knowledge and experience by providing comments, successfully
applied alternative methods or other emission inventory information
useful to other users of these volumes.  Please forward comments to the
U.S. Environmental Protection Agency, Air Management Technology Branch,
(MD-14), Research Triangle Park, NC 27711.  Such responses will provide
guidance for revisions and supplements to these volumes.
     Other U.S. EPA emission inventory procedures publications:

          Procedures for the Preparation of Emission Inventories for
          Volatile Organic Compounds,  Volume I,  Second Edition,
          EPA-450/2-77-028,  U.S. Environmental Protection Agency,
          Research Triangle  Park, NC,  September 1980.

          Procedures for the Preparation of Emission Inventories of
          Volatile Organic Compounds,  Volume II:   Emission Inventory
          Requirements for Photochemical Air Quality Simulation  Models,
          EPA-450/4-79-018,  U.S. Environmental Protection Agency,
          Research Triangle  Park, NC,  September 1979.

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                                          EPA-450/4-81-026a
Procedures for Emission Inventory Preparation

 Volume I:  Emission Inventory Fundamentals
                              by
                    Monitoring and Data Analysis Division
                   Office of Air Quality Planning and Standards
                  U.S. ENVIRONMENTAL PROTECTION AGENCY
                     Office of Air, Noise and Radiation
                   Office of Air Quality Planning and Standards
                  Research Triangle Park, North Carolina 27711

                          September 1981

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This document is issued by the Environmental Protection Agency to report
technical data of interest to a limited number of readers.  Copies are
available free of charge to Federal employees, current EPA contractors
and grantees, and nonprofit organizations - in limited quantities - from
the Library Services Office (MD-35),  U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina 27711; or, for a fee, from the
National Technical Information Service, 5285 Port Royal Road, Springfield,
Virginia 22161.
This report was furnished to the Environmental Protection Agency by GCA
Corporation, Bedford, Massachusetts 01730, in fulfillment of Contract
No. 68-02-3087.  The contents of this report are reproduced herein as
received from GCA Corporation.  The opinions, findings and conclusions
expressed are those of the author and not necessarily those of the
Environmental Protection Agency.
         **»•=*,»...
         *->'  •
                     Publication No. EPA-450/4-81-026a
                                    ii

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                               TABLE OF CONTENTS
Section

              List of Figures	    v
              List of Tables	    vi

1.0    INTRODUCTION	    1-1
       1.1    Background	    1-1
       1.2    Emission Inventory Overview	    1-6
       1.3    Purpose and Organization of the Procedures for
              Emission Inventory Preparation Series	    1-8
              1.3.1    Volume I:  Emission Inventory Fundamentals  .    1-9
              1.3.2    Volume II:  Point Sources	    1-9
              1.3.3    Volume III:  Area Sources	    1-9
              1.3.4    Volume IV:  Mobile Sources	    1-10
              1.3.5    Volume V:  Bibliography	    1-10

2.0    MANAGEMENT AND PLANNING OF THE EMISSION INVENTORY PROGRAM . .    2-1
       2.1    Emission Inventory Program Organizational
              Structure	    2-2
              2.1.1    Agency Organizational Structure 	    2-2
              2.1.2    Emission Inventory Task Force Organizational
                       Structure	    2-4
       2.2    Planning	    2-6
              2.2.1    General Planning Considerations 	    2-6
                       2.2.1.1    End Uses of the Inventory  ....    2-7
                       2.2.1.2    Sources of Emissions 	    2-7
                       2.2.1.3    Point/Area Source Distinctions . .    2-8
                       2.2.1.4    Geographical Area/Spatial
                                  Resolution	    2-9
                       2.2.1.5    Temporal Resolution  	    2-9
                       2.2.1.6    Data Collection Methods  	    2-9
                       2.2.1.7    Special Procedures 	    2-10
                       2.2.1.8    Emission Projections 	    2-10
                       2.2.1.9    Status of Existing Inventory . . .    2-11
                       2.2.1.10   Data Handling  	    2-11
                       2.2.1.11   Quality Assurance  	    2-12
                       2.2.1.12   Documentation  	     2-15
                       2.2.1.13   Emission Inventory Manpower
                                  Requirements 	     2-15
              2.2.2    Specific Procedures 	     2-16
              2.2.3    Project Schedules   	     2-18
                       2.2.3.1    Scheduling  Techniques  	     2~18
                       2.2.3.2     Task Sequence	     2-19
                       2.2.3.3     Task Schedules  .....  	     2-21
                       2.2.3.4     Example of  Project  Scheduling   .  .     2-23
                                      111

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Section
3.0    APPLICATIONS AND USERS  	
       3.1    Applications of the Inventory  	
              3.1.1    State Implementation Plan (SIP) Preparation
                       and Review  	
              3.1.2    Strategies Development  	
              3.1.3    Dispersion Modeling 	
              3.1.4    Reasonable Further Progress (RFP) 	
              3.1.5    Prevention of Significant Deterioration .  .
              3.1.6    Offsets 	
              3.1.7    Environmental Impact Analysis 	
              3.1.8    Ambient Monitoring Network Design 	
              3.1.9    Enforcement and Compliance  	
              3.1.10   Emission Trends 	
              3.1.11   Energy Analysis . 	
              3.1.12   Research  	
       3.2    Users of the Inventory 	
              3.2.1    State and Local Agencies  	
              3.2.2    Citizen Use 	
              3.2.3    Government Contractors/Institutional  . .  .
              3.2.4    Federal (Non-EPA) 	
4.0    INVENTORY DATA REQUIREMENTS 	
       4.1    Point Sources  	
              4.1.1    Plant Level 	
              4.1.2    Process Level	
              4.1.3    Point Level 	
       4.2    Area Sources . . 	
              4.2.1    Air Quality Control Region Level  . .
              4.2.2    County Level	
              4.2.3    Grid Level  	
       4.3    Mobile Sources 	
              4.3.1    Air Quality Control Region and County
                       Levels  	
              4.3.2    Grid Level  	
       4.4    Temporal Resolution  	
5.0    EMISSION INVENTORY DATA COLLECTION  	
       5.1    Information Sources  	
       5.2    Data Collection  	
              5.2.1    Questionnaires  .... 	
              5.2.2    Filling Data Gaps 	
       5.3    Calculation of Emissions 	
       5.4    Data Assessment and Quality Assurance  •  •
       5.5    Emission Inventory Maintenance and Update
6.0    PRESENTATION OF INVENTORIES/DATA SYSTEMS
       6.1    Presentation Techniques  	
       6.2    Summary of Inventory Data Systems
7.0    MANPOWER/RESOURCE ALLOCATION MODEL

APPENDIX A - DEFINITIONS 	
                                       IV

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                                 LIST OF FIGURES


Figure                                                                  Page

2-1           A typical organizational structure of an air pollution
              control agency 	    2-3

2-2           Example of a portion of a network	    2-22

2-3           Project schedule with milestones  	    2-24

2-4           Program schedule chart  	 .....    2-25

3-1           Flow diagram for the development of a control
              strategy	    3-4

5-1           Sample format for a questionnaire cover letter  ....    5-5

5-2           Sample of questionnaire general instruction sheet  .  .    5-6

6-1           Emission Inventory System - Source Record   	    6-2

6-2           New York - AIR 100 Source Record	    6-3

6-3           Nationwide emission estimates, 1977  	  •    6-5

6-4           NEDS annual fuel summary report	    6-6

6-5           Mr pollutant emissions in AQCR 215-Metropolitan
              Dallas - Fort Worth (TX)	    6-7

6-6           Air emissions of pollutants in the United States . .  .    6-8

6-7           An example of pie chart displaying the distribution
              of VOC emissions in a survey area	    6-9

6-8           Energy consumption by economic sector  ........    6-10

6-9           Total annual emission estimates for U.S.  municipal
              incineration systems 	    6-11

6-10          Historical particulate emissions by source
              category	    6-13

6-11          Energy consumption by fuel use and consumer
               category	    6-14

6-12          Particulate emission density,  by state 	    6-15

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Figure                                                                  Page

6-13          Nitrogen oxide emission density by county  	    6-16

6-14          Location and emission rate of all plants
              emitting S02	      6-17

7-1           Time requirement model—graphical representation . . •    7-2
                                 LIST OF TABLES


Table                                                                   Page

1-1           National Emissions,  1977	    1-5

3-1           PSD Industrial Categories	    3-7

3-2           Air Quality Increments ..... 	    3-8

5-1           Example of Internal  Consistency Checks for Boilers • •    5-10

5-2           Errors and Error Sources in the Emission Inventory
              Process	    5-11

5-3           Examples of Preventive Quality Assurance
              Techniques	    5-13

5-4           Examples of Corrective Quality Assurance
              Techniques	    5-15

7-1           Time Requirement Model (TREM) Summary  	    7-4
                                       VI

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                                1.0  INTRODUCTION
     This volume is the first of a five volume  series designed  to  assist
personnel of air pollution control agencies in  preparing and maintaining
emission inventories.  The next three volumes address specific  areas  of the
                                                                   19
Inventory process, namely the preparation of inventories of point,x area,^
and mobile^ sources, respectively; the fifth volume^ is a bibliography of
pertinent publications relating to inventorying activities.  Emphasis in this
series is placed on a systematic approach to identifying emission  data
requirements and sources; collecting and processing the required Information;
and presenting the data in a format consistent  with the intended application
of the inventory.  Although specific procedures for preparing the  emission
inventory are provided whenever possible, available options and the reasons
for them are identified and discussed.

     Specifically, this volume Is presented as  a reference guide for managers
and planners of state and local air quality control programs.   In  conjunction
with the other volumes, it serves as a resource for management's use  in:

     1.   Planning an emission inventory,

     2.   Establishing an agency organization to carry on the emission
          inventory programs, and

     3.   Establishing documented procedures and quality assurance activities
          for emission Inventory programs.

All volumes of this manual will be updated periodically to reflect current
practices in inventory preparation and management.

1.1  BACKGROUND

     An emission inventory is, ideally, a comprehensive, accurate and current
accounting of air pollutant emissions and associated data from sources within
the inventory area over a specific time Interval.  In addition to emission
data, the information contained in the inventory data system will Include
source, dispersion modeling, pollution control  and compliance information
which can be used by the agency to determine the present and projected effect
of emissions on ambient air quality.

     Emission inventories have been used for many years by state and local
agencies to quantify pollutant emissions within their jurisdictions.  Together
with ambient monitoring data,  inventory emission estimates have been used as a
direct indicator of annual changes in air quality.  The inventory is also
routinely used in the conduct of many air quality programs.   For example,
compliance inspections typically begin with a review of inventory-provided
source data and the siting of ambient monitoring stations is often dependent
upon emission information maintained  in the inventory.
                                       1-1

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     Many state agencies initially developed emission inventories to assist
them in the development of State Implementation Plans (SIPs).  These plans
were required by Section 110 of the Clean Air Act and set forth the state's
strategy for attaining and maintaining national ambient air quality standards
(NAAQS).  The use of an inventory became mandatory for certain areas with
adoption of the Clean Air Act amendments in 1977.  The nonattainment plan
provisions (Section 172) of the amendments require the use of an inventory to
document emissions in nonattainment areas.

     To meet the reporting requirements of the nonattainment plan provisions,
states are required to provide an emission inventory of point and area sources
for the pollutant of nonattainment.  Currently the EPA is requesting that
states submit the emission inventory of the nonattainment areas 1 year after
the date their revised SIP was submitted to the EPA Regional Office and
resubmit annually for as long as the area retains Its nonattainment
designation.  The EPA has not formally proclaimed a specific reporting format,
however, the data submitted should be readily converted to the National
Emissions Data System (NEDS) format.5

     In addition, under the published provisions of Title 40 of the Code of
Federal Regulations Part 51 (40 CFR 51), Subpart 51.321, state agencies are
required to report annually point source emission data for certain sources to
the appropriate regional office of the EPA.  Point sources subject to the
annual emission reporting requirements are:

     any facility that actually emits a total of 90.7 metric tons (100 tons)
     per year or more of particulate matter, sulfur oxides,  hydrocarbons, or
     nitrogen oxides;

     any facility that actually emits a total of 907 metric tons (1000 tons)
     per year or more of carbon monoxide; and

     any facility that actually emits a total of 4.5 metric tons (5 tons) per
     year or more of lead or lead compounds measured as elemental lead.

In addition, reporting of annual emissions from Individual emission points
within a facility Is required for those points for which:

     actual emissions of particulate matter, sulfur oxides,  hydrocarbons and
     nitrogen oxides equal or exceed 22.7 metric tons (25 tons) per year;

     Actual emissions of carbon monoxide equal or exceed 227 metric tons (250
     tons) per year', and,

     Actual emissions of lead, or lead compounds measured as elemental lead,
     equal or exceed 4.5 metric tons (5 tons) per year.

     The provisions of 40 CFR 51 require that particulate matter, sulfur
oxides, carbon monoxide, nitrogen oxides, and hydrocarbon emission data be
submitted in the format of the NEDS point source coding forms.  Emission data
                                      1-2

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 for  lead  or lead compounds measured as elemental  lead must  be  submitted  in  the
 format of the Hazardous and Trace Emissions System^  (HATREMS)  point  source
 coding forms.*

     State agencies are required to submit emissions data in the  annual  report
 for  any point source for which one or more of  the  following conditions occurs:

     A source achieves compliance at any time  within the reporting period with
     any  regulation of an applicable plan,

     A new or modified source receives approval to construct during  the
     reporting period or begins operating during  the reporting period,

     A source ceases operations during the reporting period, and

     A source's emissions have changed more than  5 percent  from the  most
     recently submitted emissions data.

 Concerning the last requirement, if it is determined that emissions  from any
 point source have not changed more than 5 percent  from the most recently
 submitted emission data, the state shall only  update the year  of  record of  the
 previously reported emission data.

     While the development and maintenance of  comprehensive emission
 inventories are specifically mandated by the Clean Air Act for nonattainment
 areas, it is apparent that numerous other sections of the Act establish
 requirements which will also compel regulatory control agencies to compile
 source/emission data in some form.  Specifically, source/emission inventory
 information will be necessary to:

     Monitor sources for emissions (with exemptions under control of pollution
     from federal facilities (Section 118), enforcement orders under federal
     enforcement (Section 113(d)) suspension orders under implementation plans
     (Section 110(f) or (g)), or orders under primary nonferrous smelter
     orders (Section 119)) which may be responsible for the failure  of the
     state implementation plan to accomplish the objectives of achieving the
     primary and secondary NAAQS (Section 110(a)(3)(c)).

     Determine the extent to which State Implementation Plans for attainment
     of the NAAQS for 862 and particulate are dependent upon gas,  oil and/or
     low sulfur coal supplies as required by the Assurance of Adequacy of
     State Plans (Section 124).
*There are no requirements in 40 CFR 51 for the reporting of area source
 emissions.
                                      1-3

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     Provide data for air quality modeling as described in Standardized Air
     Quality Modeling (Section 320(d)) necessary to carry out the prevention
     of significant deterioration (PSD) required by Part C— Prevention of
     Significant Deterioration of Air Quality (Section 160-169).

     Inventory "Major Sources" defined in Definitions (Section 169) along with
     start of construction and start of operation dates to determine their
     contribution to baseline concentrations defined in Definitions (Section
     169), or increments and ceilings as defined in Increments and Ceilings
     (Section 163).

     Identify "Major Sources" described in Increments and Ceilings (Section
     163(3)) when emissions may be exempted (temporarily or otherwise) from
     deterioration compliance with the maximum allowable increases in ambient
     concentrations of an air pollutant.

     Monitor increases and decreases of individual source emissions as
     mentioned in Nonattainment Areas (Section 129) during the interim period
     until new SIPs are approved, and

     Exchange data among states as may be required under Interstate Pollution
     Abatement (Section 126).

     EPA requires that emission data be reported to them in NEDS format.  NEDS
specified data and NEDS format must therefore be considered at a minimum by a
local agency interested in designing and implementing its own system.  NEDS is
a component of the federal air information system, AEROS (Aerometric and
Emissions Reporting System).^  AEROS was established by the EPA to serve as
a management information system for its air pollution programs.

     NEDS was the first federally-sponsored air pollutant emission inventory
system, and has served as a model for many subsequent local inventory
systems.  NEDS is a computerized data handling system which compiles, stores,
and reports on information relating to sources of any of the following five
criteria pollutants:  particulates, SOX, NOX, CO and hydrocarbons.  A
summary table taken from the NEDS 1977 National Emission Report^ shows the
annual United States emissions of pollutants by source category (Table 1-1).
In NEDS, a major distinction is made between two types of sources:  point
sources and area sources.  Point sources are stationary sources large enough
to be identified and individually maintained in the inventory.  Area sources
are those stationary and mobile sources which individually do not qualify as a
point source and are too small and numerous to be maintained separately in the
inventory.  In the NEDS, area sources are considered collectively on a county
basis.  Area sources include small stationary sources such as gasoline service
stations, domestic and commercial heating, and all mobile sources.  However,
because of their distinct characteristics, mobile sources are treated
separately in this series as a separate component of the emission inventory.
                                     1-4

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     The EPA Regional Offices are responsible for receiving, processing and
editing NEDS data.  The Regional Offices and the National Air Data Branch of
OAQPS also provide automatic data processing assistance to state and local
agencies in areas such as data processing and auditing and personnel
training.  A majority of the states are currently compiling their inventory
data on the EPA-developed Emission Inventory System/Point Source Subsystem
(EIS/PS)' and the Emission Inventory System/Area Source Subsystem
(EIS/AS)8 of the Comprehensive Data Handling System (CDHS).  Through EPA,
programs are available that convert CDHS data to the NEDS point source and
area source formats and allows data to be added, changed, and deleted.  The
CDHS subsystem programs satisfy state requirements for reporting source
emission data annually to EPA.

     The Aerometric Information Reporting System (AIRS) has been proposed by
EPA to replace the existing AEROS and CDHS systems.  This system will
integrate all data pertaining to Air Quality Siting, Raw Air Quality Data, Air
Quality Summary Information, Point and Area Source Engineering and Enforcement
Information, and Air Quality Assurance Information.  AIRS will provide state
agencies with direct access to the data base for editing and validation of
input data and for report retrievals.  The system will also provide increasing
report capabilities for all users (such as graphics and statistical analysis
packages) and will incorporate a more flexible system design capable of
meeting changing aerometric data requirements as well as allowing states to
define and store unique sets of data in addition to those data required to be
reported to EPA.  A target date of 1985 is set for operation of this new
system.

1.2  EMISSION INVENTORY OVERVIEW

     Because an emission inventory is the repository for pollutant related
data, it is the key element in all agency programs aimed at improving and
maintaining air quality within the Agency's jurisdiction.  The impact of
control strategies on emissions can be directly assessed and the resulting
impact on ambient air quality determined by dispersion modeling.  Although the
major purpose of the Inventory is to quantify all emissions within the total
jurisdiction, the Agency may at certain times focus its activities on specific
pollutants; e.g., nonattainment pollutants, or special geographical areas,
such as areas of high emission density.  Once the key sources and source
categories are identified by management, the source and emission data are
obtained by means of survey questionnaires, source inspections, permit
application reviews, statistical data source analysis or other means.  Actual
quantification of emissions is accomplished through the use of source tests,
material balances, or the application of emission factors.  Once this initial
quantification effort is completed, the Inventory must be regularly maintained
by updating source activity information and by adding or deleting sources as
such events occur.  Emission inventory maintenance efforts must be planned to
ensure that the inventory data are current and accurate and sufficient for the
needs of the agency.

     The emission inventory process can be divided into the following
components:^


                                       1-6

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     Planning—Mangement must identify emission inventory  requirements
     associated with agency programs and integrate  the inventory activities
     into their overall program by assigning an inventory  coordinator and
     establishing a work group structure.  The various planning aspects
     discussed in the following chapter should all  be considered prior to
     initiation of the actual data gathering phase  of the  inventory effort.
     Documented written procedures must be developed for all inventory
     activities including source identification, data collection and analysis,
     data reduction and insertion into the source file record format,
     presentation of the data, and quality assurance.  All procedures should
     be documented for approval by management and the technical staff prior to
     the initiation of data gathering activities.

     Data Collection—A major distinction involves  which sources should be
     considered point sources in the inventory and  which should be considered
     area sources.  Fundamentally different data collection procedures are
     used for these two source types.  Individual plant contacts are used to
     collect point source data, whereas collective  information is generally
     used to estimate area source activity and emissions for area source
     categories.  Much more detailed data are collected and maintained on
     point sources.

     Data Analysis—All source data collected must  be checked for completeness
     and accuracy.  Calculation of emissions, using source test data, material
     balance and emission factors, and examination  of process information
     should be undertaken to validate the data or to identify potential
     errors.  Recontacting of specific point sources and sources of area
     source activity data may be necessary to correct deficiencies.

     Data Reduction and Formatting—The validated data and source infomration
     must be reduced to a predesigned uniform source format and entered into
     the data file.  A computerized data file is recommended to facilitate
     calculations and error checks us'ig documented quality assurance
     procedures.

     Data Reporting—Various report formats and presentation styles need to be
     investigated and formats adopted consistent with the data handling system
     and the intended applications of the inventory data.

     An emission inventory data system is an information recordkeeping and
processing system designed around emission data.  The system may be either
manual or automatic,  but must be designed to handle all source information
deemed by the agency to be relevant to their programs.   Automated system
designs must incorporate retrieval capabilities that allow the agency to
segregate all sources with a common operating or emission characteristics
(pollutant emission rate,  process type,  location,  etc.).   The system must be
sufficiently flexible to allow the recording of point,  area,  mobile,  and
fugitive dust source  data.
                                      1-7

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     The following Information is typically required for point source and area
sources.  (Data requirements for State Implementation Plans are specified in
40 CFR 51, Appendix E and F for point and area sources,  respectively.)

     Point Source Data
          General source information—Name, address,  type of source, year
            of record,  comments,  etc.
          Emission-related data—Operating or production rate, estimated
            emissions,  EPA calculated  emissions,  control device type and
            efficiency, etc.
          Modeling parameters—UTM coordinates of source, stack height, and
            diameter,  exhaust gas temperature, and flow rate.
          Compliance-related information—Allowable emissions, applicable
            control regulations,  compliance status, and schedules, etc.

     Area Source Data

          General source information—Name and location of area (county)
            source, population, year of record.
          Activity levels—Countywide  activity level of each area source
            category (e.g., tons  of coal burned in all residential space
            heating equipment in a county).
          Emission data—Emission estimates for the entire county, for each
            pollutant and for each area source category.

     Whatever the intended use of the  immediate inventory activity, it must be
conducted using standard documented methods.  It  is also necessary that
standard procedures for maintaining and updating  the comprehensive inventory
be developed to ensure that the inventory remains accurate and complete.

1.3  PURPOSE AND ORGANIZATION OF THE PROCEDURES FOR EMISSION  INVENTORY
     PREPARATION SERIES

     The emission inventory preparation series consists of five separate
volumes and serves as a comprehensive  technical reference manual for
establishing an emission inventory of  point, area and mobile sources.  The
series, prepared for use by state and  local air quality control agencies,
presents the most recent techniques for obtaining, quantifying and handling
emission related data.   The series consists of the following volumes:

     Volume I—Emission Inventory Fundamentals

     Volume II—Point Sources

     Volume III—Area Sources

     Volume IV—Mobile  Sources

     Volume V—Bibliography
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     Each volume defines the rationale and procedures necessary  to prepare  or
upgrade an emission inventory and includes examples to assist  the user in
understanding specific methods and procedures.  An important feature  of  the
multivolume series is the fact that it can be updated periodically to include
new information on pollutants, source categories, emission  factors and data
handling as it becomes available.

1.3.1  VOLUME I:  EMISSION INVENTORY FUNDAMENTALS

     Emphasis is placed in this volume on the need for careful planning  to
ensure that the emission inventory is accurate, complete and current  and is
consistent with agency requirements, Including manpower and schedules.   The
many applications and users of the inventory are identified and  data
requirements for various levels of a comprehensive inventory are noted.  The
process of collecting and quantifying emission data is next addressed
including a section on data analysis and validation, quality assurance and
inventory maintenance.  General techniques for displaying inventory
information are presented with several illustrative examples shown.   Finally,
this volume presents a manpower resource model in which the time required to
complete each individual task of inventory preparation is estimated.  This
model will assist managers in estimating inventory manpower requirements.   An
appendix to Volume I includes a glossary of terms employed  by air pollution
control agencies in conducting emission inventories (and other regulatory
functions).  This list of terms provides a uniform set of definitions which
can be consistently and logically applied during the inventory process.

1.3.2  VOLUME II:  POINT SOURCES

     Volume II provides methods and techniques for identifying and quantifying
the emissions from point sources of pollution.  Techniques  for identifying  and
contacting all major emitters, specific data procurement techniques,  methods
of data analysis and validation are presented, including procedures for  the
calculation of emissions using emission factors, process material balances  and
engineering appraisals.  Reporting techniques specific to point  sources  are
identified followed by a general discussion of problems encountered with
specific source groups, such as combustion sources, the chemical process
industry and the metallurgical industry.  Example questionnaires of both a
general and industry-specific nature are provided in the appendicies.

1.3.3  VOLUME III:  AREA SOURCES

     Volume III outlines the methods of collecting and handling emission data
from sources too small and/or too numerous to be surveyed individually,
collectively known as area sources.   Procedures are discussed which will
assist the user in identifying area source categories and important reference
materials which can be used to determine the activity levels associated  with
these source categories.  Emission factors,  emission calculations,  pollutant
allocation and projection techniques,  and methods of data presentation are
identified and reviewed to assist the agency in the preparation and
maintenance of the area source emission inventory.   Specific emphasis is
placed on the major area source categories:   combustion sources,  solid waste
disposal,  fugitive dust sources and  solvent  sources.

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1.3.4  VOLUME IV:  MOBILE SOURCES

     This volume concentrates on both traditional and nontraditional mobile
sources of pollution.  Both traditional sources, such as on-highway vehicles
and airports, and the less common sources, such as off-highway vehicles,
aircraft, railroads, and vessels, are discussed in detail.  For each category
the data requirements, sources of data, procurement techniques and calculation
methods are presented.  State-of-the-art computer dispersion modeling
techniques for this group of sources are discussed.

1.3.5  VOLUME V:  BIBLIOGRAPHY

     This volume presents an extensive listing of reference material currently
available In the literature which will assist the user in the development of
the emission inventory.  A concise abstract outlining the pertinent emission
inventory information is provided for each reference cited.

References for Chapter 1.0

1.   Procedures for Emission Inventory Preparation - Volume II;  Point Sources,
     EPA-450/4-81-026b, U.S. Environmental Protection Agency, Research
     Triangle Park, NC, September 1981.

2.   Procedures for Emission Inventory Preparation - Volume III;  Area Sources,
     EPA-450/4-81-026C, U.S. Environmental Protection Agency, Research
     Triangle Park, NC, September 1981.

3.   Procedures for Emission Inventory Preparation - Volume IV:  Mobile
     Sources, EPA-450/4-81-026d, U.S. Environmental Protection Agency,
     Research Triangle Park, NC, September 1981.

4.   Procedures for Emission Inventory Preparation - Volume V;  Bibliography,
     EPA-450/4-81-026e, U.S. Environmental Protection Agency, Research
     Triangle Park, NC, September 1981.

5.   AEROS Manual Series, Volume II, AEROS User's Manual, EPA-450/2-76-029,
     U.S. Environmental Protection Agency, Research Triangle Park, NC,
     September 1980 (Update No.  3).

6.   1977 National Emissions Report, EPA-450/4-80-005, U.S. Environmental
     Protection Agency, Research Triangle Park,  NC, March 1980.

7.   The Emission Inventory System/Point Source User's Guide, EPA-450/4-80-010,
      U.S. Environmental Protection Agency, Research Triangle Park, NC, May
     1980.

8.   The Emission Inventory System/Area Source User's Guide, EPA-450/4-80-009,
     U.S. Environmental Protection Agency, Research Triangle Park, NC,  May
     1980.
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9.   Procedures for the Preparation of Emission Inventories for Volatile
     Organic Compounds, Volume I, Second Edition,  EPA-450/2-77-028, U.S.
     Environmental Protection Agency,  Research Triangle Park, NC, September
     1980.
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         2.0  MANAGEMENT AND PLANNING OF THE EMISSION INVENTORY PROGRAM
     The air pollution emission inventory provides the technical foundation
for all agency programs designed to improve or maintain ambient air quality
within its jurisdiction.  An accurate, comprehensive, and current record of
all sources of air pollutants and their emissions is essential for the
assessment of existing air quality and the development of future control
           19
strategies-J-'^

     The maintenance of the emission inventory is a dynamic process,
reflecting technical improvements in inventorying methods and procedures and
the changing patterns of emissions within a region.  Periodic updates, in
addition to providing a current data base, can further improve the accuracy
and usefulness of the inventory as:

     (1)  additional information is added to improve the spatial and temporal
          resolution of the Inventory;

     (2)  new technology is used to identify additional sources, develop and
          improve emission factors, and provide better definition of emissions
          with regard to speciation (e.g., compound identification of VOC
          emissions or the fine particulate fraction of total particulate
          emissions) and new pollutant identification (e.g., hazardous
          pollutants);

     (3)  data management systems are upgraded to improve data handling,
          analysis, validation and reporting;  and

     (4)  errors are eliminated and confidence in the reliability of the
          inventory improved through documentation, quality assurance, and
          ultimately the demonstrated utility of the Inventory for assessing
          control strategies and air ruality.

Agency management is charged with the responsibility of developing,
maintaining, and upgrading the inventory.  To effectively carry out  this
mandate, management must:

     (1)  Understand and appreciate the uses and significance of the inventory
          as applied to existing and future agency programs (as a corollary,
          management must also understand the limitations of the existing
          inventory and the benefits to be realized from activities  aimed at
          reducing these limitations);

     (2)  Understand the managerial and technical requirements involved in
          emission inventorying activities which require:

          (a)   Interfacing of personnel and support facilities within the
               agency to provide the full range of necessary skills;

          (b)   Identifying all methods  and procedures used in inventorying;

                                     2-1

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          (c)  Training of personnel In the use of the above techniques;

          (d)  Utilizing, to the extent possible,  technical support within and
               outside the agency to upgrade the inventory process; e.g., by
               updating emission factors, utilizing available computer
               programs,  or identifying useful data bases available within the
               agency or  from other Federal, state and local agencies;

          (e)  Documenting inventorying activities and using quality assurance
               procedures to eliminate errors from the data base and assess
               the quality of the inventory; and

     (3)  Utilize (1) and (2) above to effectively plan and conduct inventory
          activities within a schedule consistent  with the immediate and the
          overall needs of the agency.

The uses and applications of the emission inventory are described in detail in
Chapter 3.  Specific limitations of the inventory  and corrective procedures
are discussed in detail in Volumes II,  III, + and  IV-* which discuss
inventorying methods and  procedures for point, area, and mobile sources,
respectively.  The following subsections within this Chapter will address the
managerial and technical  requirements of inventorying activities and the
planning and scheduling of such activities by agency management.

2.1  EMISSION INVENTORY PROGRAM ORGANIZATIONAL STRUCTURE

     Management must have a thorough knowledge of  the organizational structure
of the air quality agency and the areas of responsibility of each department
or branch within the agency.  This knowledge is necessary because emission
inventory activities, in  most agencies, are carried out by emission inventory
program personnel drawn from several branches of the agency.  Management must
establish priorities, vis-a-vis other branch and interbranch activities,
assemble an emission inventory projtct team, and establish and maintain a
project plan, including schedule, consistent with  the priorities and magnitude
of the inventorying effort.

2.1.1  AGENCY ORGANIZATIONAL STRUCTURE

     Typically, local and state agencies are divided into various areas of
responsibility."  The specific organizational structure will vary from
agency to agency, and may not be identical to that presented in Figure 2-1.
However, the following discussion of branch functions is relevant to all
agencies, regardless of their individual organizational structure.

     The Engineering Branch handles source-related functions that Involve
process, control system,  and emission analyses.  The results of such
activities provide primary inputs to agency actions such as the issuing of
construction, operating,  emissions offsets, and prevention of significant
deterioration permits; new source reviews; environmental impact reviews;
emission inventory operations; and any special studies such as energy
analysis.  While engineers in this group operate primarily in the central
agency office, they make  field visits as required.

                                    2-2

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     The Transportation and Planning Branch is involved with all mobile source
and planning activities.  In addition to their involvement with the automobile
inspection and maintenance program, this branch is responsible for the
development of new regulations, implementation plan reviews, and control
strategy development for mobile sources.  This branch also prepares all land
use density maps and similar aids used in highway maintenance planning.
Overall, their function is analysis related.

     The Technical Services Branch provides support through laboratory
analysis and quality control operations.  Laboratory activities conducted in
support of ambient monitoring and stack testing, oil or hazardous waste sample
analysis and quality assurance and quality control programs, such as equipment
calibration and laboratory performance audits, are the responsibility of this
branch.

     Engineers and inspectors working in the Enforcement and Compliance Branch
are responsible for source activities related to compliance, as well as for
the operation of ambient monitoring stations.  All compliance, NSPS, and
NESHAPS inspections, as well as source, testing and routine source surveillance
programs, are conducted by this branch.  The investigation of special
problems, such as events involving chemical spills and hazardous waste sites,
is carried out by the Enforcement Branch which concentrates on field
activities.

     Typically, there is substantial ongoing interbranch activity.
Engineering and Planning Branches often rely on data obtained by the
Enforcement Branch.  This branch, in turn, relies on laboratory support for
technical services, and all branches utilize support services such as data
processing.  Few agency activities are totally the jurisdiction of one
branch.  Due to this interbranch coordination, the formation and operation of
an emission inventory task force will not require substantial, if any, changes
in the typical operational mode of the agency.

2.1.2  EMISSION INVENTORY TASK FORCE ORGANIZATIONAL STRUCTURE

     Most agencies, as a result of ongoing inventorying efforts, will have in
place a structure consisting of personnel charged with the responsibility of
maintaining the emission inventory data file and with conducting additional
inventorying activities as required by the agency.  The existence of an
emission inventory activity and structure within an agency provides the
foundation for any additional emission inventory activity deemed necessary by
the agency.

     All emission inventory activity should be undertaken under the direction
of an emission inventory program coordinator.  The coordinator, typically a
member of the Engineering Branch, will be responsible for the day-to-day
inventorying activities, transforming management directives and guidelines
into specific tasks and actions.  The coordinator will also play an active
role in defining the short and long term goals of the emission inventory
process consistent with the needs of the agency.  Program plans relating to
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 maintaining  and upgrading  the  inventory  and for conducting specific
 assignments  to assist  the  agency  in its  assessment  of  control strategies will
 be  prepared  by the  coordinator in conjunction with  management.   These plans,
 whether  defining  long  range  goals or short  term objectives of specific
 emission inventory  activities,  should define manpower  requirements and
 schedules and fully document in writing  the objectives and procedures of the
 inventorying activity.

     All personnel  who will  be involved  in  emission inventory activities such
 as  data  collection  and processing should be made aware of  the reason for their
 involvement  and be  able  to relate their  activities  to  those of  other members
 of  the project team and  to the needs of  the agency.  Certain short term
 objectives of the inventory  will  also set specific  data requirements.   For
 example,  an  agency  as  part of  its ongoing emission  inventory may elect to
 include  in its point source  file  all dry cleaning sources  or all sources of
 lead.  In such specific  inventory activities the number of pollutants  to be
 surveyed, their level  of temporal and spatial resolution,  and industrial and
 source descriptions are  data established by the specific requirement for the
 inventory.

     Management must decide  the most cost-effective  means  of obtaining and
 processing the required  data for  the maximum number  of sources.   Management
 may choose to use a questionnaire in order  to contact  sources rather than
 actual source visits,  or it  may decide to survey only  selected
 "representative"  sources,  and  scale the  data to the  entire sample population.
 Management's selection of  a  collection method will  also be affected by the
 availability of automatic  data  processing (ADP) capability.   Large-scale
 inventory efforts,  involving hundreds of sources, will realistically use
 ADP.1»2   Manual techniques,  while practical for smaller inventory efforts,
 cannot efficiently  handle  the  extensive  amount of data collected for a
 comprehensive emission inventory.   Management must  decide  the extent of the
 inventory in terms  of industries  and sources to be  surveyed,  inventory
 methods,  use of ADP, and overall  manpower and resource commitments.  The
 performance  of specific  work aspects ot  the program  should be left to  the
 coordinator.  Questions  such as who will log in returns, what to include in a
 survey questionnaire, and  how  and when to recontact  sources  for  data
 verification should be the responsibility of the coordinator.  This  individual
 should be best able to handle  the day-to-day needs of  the  project.

     An  end  result  of the  development  of  the project plan  will be an estimate
 of  the manpower requirements and  schedule.''***  To ensure that the emission
 inventory accomplishes all of  its  objectives,  yet minimizes  resource
 requirements, a manpower utilization plan must  be developed.  To do  so,  the
 emission  inventory  program is broken down into  its component  parts and  each
 part is allocated a given  number  of  "man-hours."  Chapter  7  of this  volume
 presents a manpower model  for a planning  effort  of this  nature,  based,  in
 large measure,  on experience and  on  information presented  in References  6
 and 7.  Personnel assignments will be  the responsibility of  the  project
 coordinator,  however,  management must  coordinate personnel assignments with
 the various  branch chiefs and establish  priorities for  assignments.
Management is ultimately responsible  for  ensuring that  tasks  are  completed


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within their allocated time frame, and redirecting resources if a problem
arises in an area that requires more time than initially scheduled.
Management must ensure that some feedback mechanism is incorporated into its
program plan.  Feedback mechanisms to quickly identify problems during the
preparation of the inventory and problems associated with the data base and
its use can forstall the development of more serious future difficulties.  The
inventory coordinator must monitor the hours spent on every task each week,
and report back to management, weekly or biweekly, on the progress of the
program.

2.2  PLANNING

     The basic elements of an emission inventory are (a) planning; (b) data
collection; (c) data analysis and validation; (d) data formatting and
handling, and (e) reporting.  Management will be most directly involved with
planning, which in itself Involves all other program elements.  Management
must hold itself responsible to initiate, conduct, and direct the completion
of a program plan and the design of a program structure for the continuous
development of the inventory.  The progress of the inventory effort should be
monitored continually and actions instituted to redirect the agency's efforts
should changes occur.

2.2.1  GENERAL PLANNING CONSIDERATIONS

     Prior to initiating the actual compilation of an inventory of point
source emissions, the agency's management and technical staff must carefully
assess the needs and objectives of the inventory.  At the end of the planning
period, and prior to initiating the data collection phase,  the agency will
have addressed the items listed below.^

     The end use(s) of the inventory are established.

     Sources and source categories have been defined which are compatible with
     available source and emission information,  and are of sufficient detail
     to facilitate control strategy projections,  excluding nonreactlve
     compounds in the case of a volatile organic compound (VOC) emission
     inventory.

     The role of existing inventory data has been determined and any
     previously omitted data and sources have been identified.

     The point source cutoff has been defined.   Sources smaller than the
     cutoff limit will be treated as area sources.

     The geographic area has been identified.  Typically, this area will
     consist of the agency's entire jurisdiction.

     Decisions have been made on whether to temporally adjust emissions, also
     to what level; seasonally or daily.

     The point source data collection methods have been determined.


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     Procedures  for  identifying  nonreactive  emissions  have been selected.

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

     An inventory data handling  system has been selected  and coding forms
     developed for loading the system..

     The agency's future use of  dispersion models  has  been considered and  the
     appropriate adjustments in  inventory plans have been made.

     Quality assurance procedures have been  selected and  a quality  assurance
     coordinator identified  for  the  program.

     Manpower and budget allocations have been  made and organization has been
     established by  assigning authority and  responsibilities.

 2.2.1.1  End Uses of the Inventory

     A basic consideration in planning the inventory is establishing the end
 uses of the completed inventory.  The  end uses  of  all  inventories fall  into
 two general categories:  (1) air quality control strategy development and  air
 quality maintenance  and  (2) air  quality research.  Possible  future  use  of  the
 inventory as well as immediate objectives should be considered  in determining
 procedure and data needs.

     The Clean Air Act Amendments of 1977 requires the development  of emission
 inventories, which are far more  detailed and comprehensive  than  previously
 specified and those  currently available in many control agencies throughout
 the country.^

     Air quality research inventories fulfill agency's requirements  for
 studying relationships between emissions and ambient air  quality.   The agency,
 during the conduct of research programs, may collect data which  is  more
 detailed and extensive than that required by legislation.   The agency can
 elect to include those data in the comprehensive inventory depending upon
 future needs and update requirements.

 2.2.1.2  Sources of Emissions

     An important consideration affecting emission inventory accuracy is
whether the agency has included all point sources and area source categories
in its emission inventory.   Volumes 11,3 HI,4 aru} jy^ describe
procedures for identifying individual point,  area and mobile source
categories.  Additional information concerning  source identification can be
found in other EPA reports such as References 8 and 9 which deal with sources
of VOC emissions.
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     It Is important that all of the emitting points that may be associated
with individual sources or source categories be identified if an accurate
inventory is to be prepared.  For example, a petroleum refinery contains many
emission points ranging from process heaters to Individual seals and pumps.
General process and emission information can be obtained from AP-42.10
Other EPA publications including the Control Technique Guidelines series for
specific VOC source categories,* Industrial Process profiles for environmental
use such as Reference 11, Source Assessment reports such as Reference 12, and
many references contained in Volume V^ Of this series provide source and
emission data that will be useful to agency personnel in preparing a complete
inventory of all sources.

2.2.1.3  Point/Area Source Distinctions

     A major distinction typically made in inventories Is between point and
area sources.  Point sources are those facilities/plants/activities for which
individual source records are maintained In the inventory.  Under ideal
circumstances, all sources would be considered point sources.  In practical
applications, only sources that emit more than some specified cutoff level of
pollutant are considered point sources-  Depending on the needs of the agency,
this cutoff level will vary.  Area sources, In contrast, are those activities
for which aggregated source and emission information are maintained for entire
source categories rather than for each source therein.  Sources that are not
treated as point sources must be included as area sources.  The cutoff level
distinction is especially important in the VOC inventory because there are
many more small sources of VOC than of most other pollutants.

     If too high a cutoff level is chosen, many facilities will not be
considered individually as point sources, and if care is not taken, emissions
from these sources may not be included In the inventory at all.  Techniques
are available for "scaling up" the area source Inventory to account for
missing sources amd are presented In References 8 and in Volume III^ of this
emission Inventory series.  Area source procedures are invariably less
accurate than point source methods.

     If too low a cutoff level is chosen, the result will be a significant
increase (1) in the number of plant contacts of various sorts that must be
made and (2) in the quantity of data that must be compiled and maintained.
While a low cutoff level may Increase the accuracy of the Inventory, the
tradeoff is that many more resources are needed to compile and maintain the
inventory.

     A required upper limit on the point source cutoff level is 100 tons/year
and a lower cutoff level is encouraged to account for many source categories
which are identifiable, controllable, and collectively significant.  For
*Available from the Director, Emissions Standards and Engineering Division,
 Mail Drop 13, U.S. Environmental Protection Agency, Research Triangle Park,
 North Carolina 27711.


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 example, many VOC sources emitting less than  25  tons  per year were  identified
 in a recent study of VOC emissions from urban industrial sources.^-^
 Moreover, many of these sources are in categories for which no  reliable  area
 source inventory procedures currently exist.  Because of this,  some agencies
 have elected to define cutoff levels at or below 5  tons per year in order  to
 include a large percentage of VOC and other emissions in the point  source
 inventory.

 2.2.1.4  Geographical Area/Spatial Resolution

     The geographical area to be inventoried  is  defined herein  as that area
 which falls within the jurisdiction of the state agency conducting  the
 inventory.  Emission points within this area  must be  precisely  located.
 Dispersion modeling studies sometimes require that  point sources be determined
 to within 10 meters.  Although existing sources  contained in NEDS are only
 specified to 100 meters, a resolution of 10 meters  Is recommended whenever
 possible.  Two grid systems have been developed  for locating geographical
 points:  (1) latitude and longitude and (2) universal transverse mercaptor
 (UTM).  Advantages of the UTM grid system include the following.

     1.   Grids are continuous and are not hindered by political subdivisions.

     2.   UTM grids are uniform.

     3.   The UTM system Is used worldwide.

     4.   The UTM system Is associated with a growing body of technical
          information.

 2.2.1.5  Temporal Resolution

     Emission data for a calendar year have historically been collected  by
most agencies, mainly because activity levels are most readily available on an
annual basis.   In some cases the agency may need to adjust annual emissions
 rates to a seasonal, daily or hourly basis.  Certain  source categories operate
only during certain hours of the day or during certain seasons of the year;
e.g., many sand and gravel operations.  Activity levels and corresponding
emissions from other categories (e.g., mobile sources, surface coating,
pesticide application and small boiler operations) are strongly temporal
dependent.  Other categories such as solvent storage  are also
temperature-dependent."  Temporal variations In emission rates,  because  of
their Influence on ambient pollutant levels,  must be  considered by  the agency
in defining the data requirements of the Inventory.

2.2.1.6  Data  Collection Methods
     Methods for collecting data for point, area and mobile sources of
emissions are presented in Volumes II, III, and IV, respectively.3>4,5
However,  the Inventorying agency must decide which procedures to use in its
inventory effort.  Point source methods include mail surveys, plant
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inspections, and use of agency permit and compliance files.  Area and mobile
source methods are usually dependent upon correlative relationships among
statistical parameters and activity levels/emissions.  The agency should
determine in the planning phase what methods and reference sources will be
used in data collection.  Early definition will allow time to obtain necessary
reference and support materials and will help to better allocate work hours to
the individual data collection tasks as well.  Data collection methods and
considerations for their use are discussed in greater depth in Chapter 5.

2.2.1.7  Special Procedures

     Special procedures may be required to obtain information not normally
obtained when compiling an emission inventory.  This information may be
temporal data or relate to pollutant characterization; e.g., fraction of
inhalable particulate or organic compound identification .  While most
volatile organic compounds ultimately engage in photochemical reactions, some
are considered nonreactive under atmospheric conditions.  Therefore, controls
on the emissions of these nonreactive compounds do not contribute to the
attainment and maintenance of the National Ambient Air Quality Standard for
ozone.  These nonreactive compounds are listed below:

          Methane
          Ethane
          1,1,1-Trichloroethane (methyl chloroform)
          Methylene chloride
          Trichlorofluoromethane (CFC 11)
          Dichlorodifluoromethane (CFC 12)
          Chlorodifluoromethane (CFC 22)
          Trifluoromethane (FC 23)
          Trichlorotrifluoroethane (CFC 113)
          Dichlorotetrafluoroethane (CFC 114)
          Chloropentafluoroethane (CFC 115)

The above compounds should be excluded from emission inventories used for
ozone control strategy purposes.  References 8 and 9 should be referred to for
more detailed information on excluding nonreactive VOC from emission totals.
Because the above list may change as additional information becomes available,
the inventory agency should remain aware of EPA policy on reactivity.

     Even though data are not needed in the basic inventory, the agency may
find it expedient to collect this information when plant contacts and surveys
are made as part of a routine update of the inventory.  If an agency
anticipates the need for special data, it is more efficient to collect the
data at the same time the other source and emission data are collected for the
basic inventory.

2.2.1.8  Emission Projections

     During the planning stage of the emission inventory, it is necessary to
identify the type of emission projection procedures that will be used.  The
two types of emission projection procedures are baseline and control


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 strategy.   The  agency will  need  to  evaluate its current emission control
 strategy and  determine  the  likelihood  of  the promulgation of additional
 control measures which  would  affect emissions during  the projection years.   If
 it  appears  that there will  be limited  changes in the  control strategy,  then
 the agency  should  plan  to employ the baseline projection procedure.  However,
 if  it appears that new  regulations  will be  enacted  which will affect
 emissions,  then the agency  should employ  the control  strategy projection
 procedure.

 2.2.1.9  Status of Existing Inventory

     A major  inventory  planning  consideration is whether or not  and to  what
 extent information contained  in  an  existing inventory can be utilized.   The
 existing inventory should be  examined  to  see if the appropriate  sources have
 been included and  that  the  emission data  are representative of current
 conditions-   Existing inventories serve as  a starting point for  developing  a
 mailing list  for questionnaire distribution and should provide extensive data
 and support information, such as documentation of procedures.

 2.2.1.10  Data  Handling

     Data handling and  retrieval can be done by computer or manually.
 Combinations  of these methods are also possible.  The selection  of  one
 approach over the other will  depend  on several factors:

     Availability of a  computer,

     Size of  the inventory data  base,

     Complexity of the emission  calculations,

     Number of calculations to be made,

     Variety  of tabular summaries to be generated,

     Availability of clerical and data handling  personnel,  and

     Time constraints.

 Computer data handling becomes significantly more cost effective as  the  data
 base, the variety of tabular  summaries, or  the number of iterative  tasks
 increases.   In these cases,  the computerized inventory requires less time and
has the added advantage of forcing organization, consistency, and accuracy.

     Some of  the activities  which can be performed efficiently and  rapidly  by
computer include:

     Printing mailing  lists  and labels;

     Maintaining status  reports and  logs;
                                      2-11

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     Calculating and summarizing emissions;

     Performing error checks and other QA functions;

     Storing source, emission, and other data;

     Sorting and selective accessing of data; and

     Generating output reports.

     During the planning stages, an agency should anticipate the volume and
types of data handling needed in the inventory effort, and should weigh
relative advantages of manual and computerized systems.  If an agency must
deal with large amounts of data, a computerized inventory data handling system
allows the agency to spend more time gathering, analyzing and validating the
inventory data as opposed to merely manipulating it.  The computerized
approach is superior for large areas having a diversity of sources comprising
a complex inventory.

     If the agency anticipates use of a photochemical dispersion model at some
future date, it is Imperative that a computerized data handling system be
utilized.  The added complexity Involved in developing spatially and
temporally resolved estimates of several VOC classes from the basic inventory
represents too much work to complete manually.  Data handling requirements for
inventories used in photochemical models are discussed in References 2 and 8.

2.2.1.11  Quality Assurance

     Quality assurance is important in achieving user confidence in an
emission inventory.  A quality assured inventory will result in a more
accurate inventory and lead to better assessment of control strategies and the
Impact of emissions on air quality.  Also, lower program costs may be realized
because inventory updates and revisions will not be as extensive as when
conducted without a quality assurance program.

     A quality assurance program applied to an emission Inventory, contains
three general types of procedures.  Standard operating procedures includes
organization planning, personnel training, project planning, and the
development of step-by-step procedures for technical tasks.  Techniques for
finding and correcting Inconsistencies and errors includes identification of
potential error sources, evaluation of the impact of these sources, location
of checkpoints for optimal problem detection, and a provision for timely
response when problems occur.  The determination of product quality and
reliability, in the context of an emission inventory, Is the same as data
quality assessment.  These procedures Include a periodic review of the entire
inventory process, the development of standards against which to test the
accuracy and precision of results, and a system evaluation to maintain optimal
resource efficiency.

     Standard operating procedures must be outlined as the inventory effort is
planned.  Identifying and correcting Inconsistencies and errors In the
inventory can also be anticipated in the planning phase.  The quality

                                       2-12

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 assurance program Is designed to minimize the following potential sources  of
 error.8

     Missing facilities or sources—Permit and inventory systems out of phase;
     errors in estimating potential emissions; lost paperwork; problems with
     computer file updates.

     Duplicate facilities or sources—Name changes through corporate
     acquisitions; use of multiple data sources with different source
     numbering schemes.

     Missing operating or technical data—Ambiguous data request forms;
     intentional deletion by facility staff; Inadequate followup procedures;
     no preliminary indication of inventory size; or overall inadequate
     project control.

     Erroneous technical data—Misinterpretation of data request instructions;
     assumed units, faulty conversions, etc.; Intentional misrepresentation by
     the facility; poor handwriting.

     Improper facility location data—Recording coordinates of facility
     headquarters Instead of the operating facility; inability of technicians
     to read maps; failure to observe inventory area boundaries.

     Inconsistent area source categories or point source sizes—Failure to
     designate inventory cutoffs.

     Inaccurate or outdated data—Mixed use of primary and secondary data
     without a policy for standardizing data.

     Errors in calculations—Transposition of digits; decimal errors; entering
     wrong numbers on a calculator; misinterpreting emission factor
     applications.

     Errors in emission estimates—Imprecise emission factors; applying the
     wrong emission factor; errors In throughput estimates; improper
     interpretation of combined sources; errors in unit conversions; faulty
     assumptions about control device efficiency; failure to exclude
     nonreactlve emissions.

     Reported emissions wrong by orders of magnitude—Recording the wrong
     identification code for subsequent computer emission calculations;
     Ignoring implied decimals on computer coding sheets;  transposition
     errors; data coding field adjustment.

     The determination of product quality requires the development of
procedures to measure the completeness and accuracy of the data file.  If a
computer data handling system is available,  a computer program can perform
checks for implausible entries,  missing data,  and conformity of calculated
results with known data relationships.  Manual spot checks on the point source
records can be performed when computers are not  available.


                                      2-13

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     Principles of quality assurance can be applied in planning, data
collection, calculations,  and reporting of the emission inventory.  Quality
assurance requires anticipating the measures needed in each of the inventory
functions.  To promote effective quality assurance, the inventory planner
should consider the steps  listed below prior to initiating inventory tasks.^

     1.   Planning

          -    Plan to allocate resources for maximum quality assurance.

          -    Plan to account for significant emission sources.

          -    Prepare a checklist of sources to be evaluated.

          -    Use staff experienced in data collection and analysis.

               Plan for routine checking of calculations.

               Plan for checking data file entries.

          -    Prepare data checking programs (when using  a computer for data
               handling).

          -    Maintain a  separate quality assurance staff.

     2.   Data collection  and analysis

          -    Use redundant identification of major sources (quality
               assurance staff should prepare an independent source list).

          -    Check questionnaire design.

          -    Check data  collected.

          -    Check emission estimation methods.

          -    Check calculated results.

          -    Verify adherence to quality assurance procedures.

     3.   Data handling

          -    Check data  file entries.

          -    Check individual data entries (missing emissions, SIC codes,
               addresses,  etc.)

          -    Assign agency estimates for missing data.

          -    Check for data correctness.

               Review tabulated data for quality.

                                      2-14

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     4.   Data reporting

               Check  the aggregation  of  emissions.

          -    Compare  results with those  of  other  Inventories.

          -    Check  disaggregation of emissions  (if  allocated to  subcouniy
               areas).

The above is Intended to acquaint  the user with the concepts  and principles of
quality assurance.  Before planning a quality assurance  program, additional
information on these  concepts and  principles  must be  obtained.  Such
information on emission inventory  quality  assurance can  be  found in References
15 through 17 or can  be obtained through an EPA Regional Office.   The most
effective instruments of quality assurance are the  standard operating
procedures developed  by the agency as these steps determine methods to  be used
throughout the inventory effort.

2.2.1.12  Documentation

     Documentation is an integral  part of  an  emission inventory.   Review of
the written documentation of an Inventory's data sources and  procedures by  the
agency's quality assurance and technical personnel  will  uncover errors  In
assumptions, calculations or methods.  Remedial actions  to  correct detected
errors will lead to the development of a reliable and technically  defensible
data base which is essential in enforcement actions,  source impact
assessments, and development of emission control strategies.

     While documentation requirements may  evolve during  the data collection,
calculation, and reporting steps of the emission Inventory, these  requirements
should be anticipated during planning.  Planning the  level  of documentation
required will (1) ensure that importnr.t supporting  information Is  properly
developed and maintained, (2) allow extraneous information  to be identified
and disposed of, thereby reducing  the paperwork burden,  (3) help determine
data storage requirements, and (4) aid in  identifying aspects of the inventory
on which to concentrate quality assurance  efforts."

2.2.1.13  Emission Inventory Manpower Requirements

     To ensure that sufficient resources have been  allocated to achieve good
results with an inventory effort, cost and manpower requirements should be
evaluated in the planning stage of the project.  Technical  manpower and budget
allocations required will be a function of the number and type of sources to
be inventoried,  the pollutants being inventoried,  and the desired data base
detail.  These Inputs, in turn,  will be affected by the  inventory end use and
by the data handling capabilities.   Administrative  and secretarial support
will be a function of the technical manpower and budget  allocations determined
by all of these  factors.^>^
                                      2-15

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     Since cost and manpower requirements will vary for each inventory effort,
manpower and budget allocations must be determined.  When an agency has
conducted inventories regularly, its past experience can be used to estimate
requirements-  A computer model is also available from EPA which estimates
technical and administrative costs associated with emission inventories.^
Information is obtained through EPA Regional Offices or from the Control
Programs Operations Branch, Control Programs Development Division, MD-15, U.S.
Environmental Protection Agency, Research Triangle Park, NC 27711.

2.2.2  SPECIFIC PROCEDURES

     Planning includes a variey of procedures that reflect agency goals and,
as a consequence, require management decisions.  These decisions address
definitional, organizational, and technical problems.16

     The definitional phase of the planning step is the one in which
management defines the system objectives and outlines the basis for meeting
those objectives.

     1.   Define objectives—This procedure requires management to assess the
          short term and long term goals of the emission inventory program-
          The purpose of the emission inventory program is to maintain a
          current and reliable data base which is used to support agency
          programs for attaining and maintaining air quality.  However,
          specific programs, for example to assess trends in emissions, can be
          conducted to satisfy specific immediate objectives as well as
          satisfying the general purpose of the inventory.

     2.   Define requirements for meeting objectives—Once the major goals of
          the emission inventory process have been identified, management,
          with assistance from the technical staff needs to define the types
          of information required and to take steps to obtain that
          information.  The steps include defining specific data requirements
          and formats, establishing the authority to obtain and verify the
          necessary emission data, and defining data quality goals.

     The organizational procedures are those that determine the total effort,
the resources that will be expended, and the relationship between the
inventory process and other agency functions.  Procedures must be established
that accomplish the following.

     1.   Relate program and agency functions—This procedure includes an
          organizational audit to define the purpose of each branch and
          subgroup within the agency and the level of support that they can
          and will provide.

     2.   Assign responsibilities—This establishes the responsibilities and
          authority of the branch or group for compiling and maintaining
          emission inventory data.  It is an early step in developing a
          mechanism for establishing the emission inventory.  It might also
          include, for example, an assessment of the degrees of support that
          branch office operations can provide.

                                       2-16

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     3.   Establish communications—This determines  the  flow of  Information
          between management and the subdivisions of  the agency.   It also
          establishes the environment for interdepartmental  transfer of
          technical data and support of the inventory and  its  programs-

     4.   Assign priorities—This function follows from  the  assessment by  the
          agency of the scope of its air pollution problems, and  the need  for
          the inventory program based on existing air quality  and  the degree
          of industrialization or urbanization of the area within  its
          jurisdiction.

     5.   Budget resources—This function Is the logical extention of the
          assignment of priorities.  Budget decisions reflect  the  expected
          impact of the emission Inventory on agency effectiveness, and  they
          affect the types of inventory procedures that will be adopted.

     6.   Document procedures—This function is the formal summary of the
          activities mentioned above.

     The technical procedures help to establish the degree of  confidence that
can be placed in the emission inventory results.  They affect  the  precision
and accuracy of the inventory, and the degree to which results can be compared
within or among agencies.  These procedures are:

     1.   Develop inventory techniques—This includes decisions about the
          emission factors to be used, techniques to Identify  sources, data
          gathering techniques, manual versus computer data  processing,
          quality assurance programs, and workflow procedures within the
          organization.  These are some examples of a range  of complex
          functions encountered in inventory programs.

     2.   Develop job descriptions—This includes writing job descriptions  for
          personnel who will be assigned exclusively to the  emission inventory
          process.  A written job description will identify  skills required to
          perform the activity; the experience and performance level of
          personnel; arid the training requirements.

     3.   Identify training requirements—This includes an evaluation of the
          technical questions that must be addressed in compiling an emission
          inventory, and the functions requiring special skills or periodic
          updating of techniques.   The training programs and schedules will be
          designed to aid In incorporating improved inventory techniques and
          to improve performance of inventory functions.

The end result of planning activity will be a documented program with specific
objectives and established priorities for achieving  the objectives within a
defined time frame and budget.   A reasonable program plan relies heavily on
input from the definitional phase  of task planning;  I.e., management
objectives,  inventory quality goals,  etc.
                                       2-17

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2.2.3  PROJECT SCHEDULES

     The Time Requirement Model (TREM) discussed in Chapter 7 allows the
manager of an emission inventory to estimate the amount of time required to
perform various activities.  However, knowledge of the tasks and their
estimated time requirements alone is insufficient to conduct the inventory
efficiently, or properly allocate the resources available.  Modern project
management techniques should be utilized to plan, control, and schedule the
numerous activities into a cohesive course of action.

     The development and maintenance of an emission inventory can be
conceptualized as a network of activities that can be mapped out on a chart.
The various inventory tasks are defined as individual activities with a
definite start and end.  The initiation and completion of an activity are
denoted by the term "event."  Techniques to formulate a project schedule for
tasks and events are then utilized.

     Program evaluation and review techniques (PERT),* Barcharts (BACH,)*
and Critical Path Method (CPM)* are relatively simple methods that are
available to identify critical activities and evaluate costs and technical
progress.  The identification of specific tasks and the logical sequence of
activities and their interrelationships within the overall program are useful
to both management and the task team in performing the various necessary
functions and identifying problem areas and viable alternative plans and
schedules.

     The scheduling techniques subsection, below, discusses some of the
available methods to efficiently organize a project such as an emission
inventory.  In particular, PERT and CPM are discussed.  The task sequences
subsection demonstrates briefly how various inventory tasks are scheduled in a
progression.  Finally, the task schedule subsection shows how the PERT or CPM
evaluation methods can be used to determine where "critical sequences" are
likely to occur in a series of events.

2.2.3.1  Scheduling Techniques

     Standardized techniques used for program scheduling and monitoring
include PERT, CPM, and variations.  These techniques are fundamentally simple,
and this fact heightens their utility.  The network or bar chart analysis
yields the following advantages for both management and agency personnel:
*Further details concerning PERT, BACH, CPM and their variations can be
 found in References 19 through 24.
                                      2-18

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     For management,

     1.   More realistic time cost estimates,

     2.   Improved program control through early detection of uncompleted
          events, and

     3.   Good simulation and projection of alternative plans and schedules;

     For agency personnel,

     1.   A better visualization of the individual tasks,

     2.   Relevant and meaningful interim schedule objectives,

     3.   Improved communication among agency personnel, and

     4.   More distinct delineation of task and decision responsibilities.

     For the purposes of PERT and CPM techniques, all objectives and goals
should be defined.  Each activity has definite start and end points that are
termed "events" or "nodes."  An event has no time duration and serves to
indicate the start or completion of an activity.  The activities are the links
connecting the events, and these have measurable performance times.

     Three basic steps are required for PERT or CPM analysis:

     1.   Develop the network of events from time of start to the completion
          of the inventory.

     2.   Estimate the time required to accomplish each activity in the
          network, using past experience of the manpower/resource allocation
          model in Chapter 7.

     3.   Perform analyses of possible schedule problems through the
          determination of the longest or "critical path" in the network of
          events.

     The PERT and CPM techniques are not meant to perform decision analysis
for the manager, but rather allow the manager to develop and order a plan of
activities,  and to determine the critical aspects of program performance.  In
anticipating problems and possible delays, the manager is able to formulate
effective corrective actions.  Viewing the entire project on a network diagram
provides a greater understanding of the coordination of activities.

2.2.3.2  Task Sequence

     In the  formulation of a project schedule,  it is necessary to establish
the sequence of activities and events using a chronological order to ensure
the elimination of conflicts.  An understanding of the  rational progression
of events is necessary for establishing the network of events required to
achieve the  desired objectives.

                                       2-19

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     The basic sequences of activities for point, area, and mobile source
inventories are:

     1.   For point source inventories:

          a.   Identification of inventory data needs;

          b.   Establishment of data collection and handling methods;

          c.   Development of a source listing;

          d.   Development of questionnaires;

          e.   Collection and compilation of data, including printing the
               mailing list and labels, mailing questionnaires, logging and
               reviewing returns, and questionnaire followup to obtain
               complete and reliable information.

          f.   Assistance to questionnaire respondents;

          g.   Transfer of data to the data handling system;

          h.   Calculation of emissions;

          i.   Quality assurance; and

          j.   Presentation of results.

     2.   For area and mobile source inventories:

          a.   Identification of inventory data needs for estimating activity
               levels and emissions,

          b.   Establishment of data collection and handling methods,

          c.   Data collection and compilation,

          d.   Apportionment of data to desired geographical and temporal
               levels,

          e.   Calculation of emissions,

          f.   Transfer of data to the data handling system,

          g.   Quality assurance, and

          h.   Presentation of results.

     The listings of sequential activities presented above are by no means
complete.  Additional intermediate steps can be included for better resolution
of manpower requirements and schedule.  However, by Inspection of the above
listings, the basic sequence of activities Is:

                                       2-20

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      1.    Identification  of  data  needs,

      2-    Establishment of methods,

      3.    Collection of data,

      4.    Analysis and compilation of data, and

      5.    Presentation of results.

2.2.3.3  Task Schedules

           The use of PERT and CPM is suggested in  order  to  determine  the
critical sequence of operating and other  specific  steps  most  likely to  cause
delays, and to aid in determining the shortest path  (or  least time, cost,
etc.) to achieve completion  of the project.  A key feature  of these techniques
is the use of "milestones" to delineate significant  points  of development  in
the inventory process.  These milestones  include:

      1.    Initiation of a specific activity,

      2.    Completion of the  activity,

      3.   Scheduled events (i.e., meetings), and

      4.    Submission of interim,  progress, and final reports.   (Typically,
          these will be oral reports to management and agency groups  not
          directly responsible for the inventory.)

      These milestones enable the manager  to monitor  the  progress of each task,
and provide the opportunity  to adjust or  reschedule events  in accordance with
the milestones.  As a project progresses, some changes in activities  will
occur and new milestones may be designated.

     Using the TREM to estimate the number of hours required,  values  can be
assigned to activities between specified  events and/or milestones.  Two
techniques are available for the determination of  the "critical path" or
longest time required to complete all the scheduled activities.  These are the
deterministic and the probabilistic approaches.  The deterministic approach
relies on only one estimate for each activity, and the analysis is then
performed.  This estimate should be performed by personnel  thoroughly familiar
with the task.  The critical path procedures are then applied  to find the
longest path through the network.  The total time  required  to  complete all
project activities is governed by the critical path (i.e.,  the longest time
path linking the initial event and the terminal event of a  project)•
Probabilistic network scheduling requires three time estimates for each
activity:   optimistic time,  pessimistic time,  and most likely  time.  This
approach recognizes the uncertainties involved in any project  and, in the most
pessimistic case,  considers  the fact that delays in other agency programs may
affect the emission inventory development schedule.
                                      2-21

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     Figure 2-2 shows a portion of  a network of events A through E and the
estimated relative time requirements (in parentheses) of activities 1 through
7.  In order to proceed from event  A to event E, the various activities will
have to be performed.  The  minimum  amount of time required to go from node A
to node E can be determined by  examining the times required to complete the
activities.  As an example, in  order to proceed from A to D, activity 3 or
activities 2 and 6 will have to be  performed.  The maximum time to complete
the AD path is the maximum  time required for activity 3 or activities 2 and
6.  In this case, the completion of event D is dependent on activities 2 and
6.  This process can be expanded to cover the AE pathways, and a critical path
determined.

     The probabilistic network  schedule utilizes three time estimates:

     1.   Optimistic time (a).   The best or shortest time required to complete
          an activity is estimated.

     2.   Pessimistic time  (b).  The longest time that an activity should take
          is estimated.

     3.   Most likely time  (m).  The time estimate which, in the estimator's
          judgment, has the probability of greatest occurrence.
          EVENTS5 A THROUGH  E
          ACTIVITIES' I THROUGH 7
          RELATIVE  TIME   REQUIREMENTS: (IN   PARENTHESES)
                Figure 2-2.  Example of a portion of a network.

                                      2-22

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     A single average estimate expression of the expected  time  to complete  an
activity is given by:

                                    a + 4m + b
                               e        6
      /    \2
with   a   , a variance in    :
      V  o I                 a
     The expected time, te, is a statistical expression with time variance
as a measure of confidence of the te value.  If the variance is small, then
the confidence in te is high; if the variance is large, then the confidence
in te is low.

     The expected time, te, should not be used to actually schedule an
activity.  However, It can be used to compare with a scheduled value and
determine the probability of meeting the scheduled time.  This allows the
manager to decide the probability of completing a task in a given time within
some confidence limits.

     Use of the deterministic and probabilistic time estimates in establishing
critical paths allows the project manager to schedule or reassign activities
as the project progresses.  In this manner, optimum use can be made of limited
resources.  In addition, information derived from CPM/PERT analysis enables
the project manager to reassess the feasibility of undertaking a given project
task.

2.2.3.4  Example of Project Scheduling

     After air quality agency manager^ut has decided upon a task sequence and
schedule for its inventory effort, this schedule and list of activities should
be summarized.  Such a summary will not only serve to Inform all program
personnel of the project schedule of activities, but can also be used to track
the progress of the emission inventory program.  The most common method of
displaying this summary is a graphical task schedule chart.  Figures 2-3 and
2-4 present typical program schedule charts.  This type of display clearly and
concisely summarizes the inventory tasks, their scheduled start and completion
dates, and major milestones that must be met.  Some charts, such as that shown
in Figure 2-3, may also include project manpower and cost data as well.

     The project schedule chart Is completed before the project is begun.  It
is based on time and manpower estimates and represents management's best
estimate of an achievable and viable schedule.   Once work on the inventory has
begun, actual progress should be tracked, recorded, and revised as needed.
The project schedule chart can also be used for this purpose.   Monthly updates
on work progress can be superimposed on the original program schedule to
reflect actual work progress.   Figure 2-4 demonstrates how this updating


                                       2-23

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technique has been used on a nonemission inventory program schedule.
Maintaining a program schedule in this manner provides an excellent historical
record of the total work effort.  In the short term, It acts as a constant
feedback mechanism to program managers who must monitor the progress of the
project.  In this manner, It ensures that no one task will be allowed to drag
on and affect the entire schedule.  In the long term, this updated schedule
chart can be used to highlight the shortcomings or successes of the original
platming effort.  Problem areas can then be more carefully researched to
ensure that the experience gained will be applied to future projects.

     A graphic display of the program schedule is useful in that it outlines
the critical and time-intensive tasks and milestones in the emission inventory
process that should be closely monitored.  A comprehensive quality assurance
(QA) program must be developed to ensure use of consistent data gathering,
handling, and analysis procedures thus helping to assure an error-free data
base.  Since each specific inventory task Is listed on this display, a quality
assurance coordinator can plan his overview checks and Inspections to
correspond to the task schedule.  The frequency of quality assurance
inspections can be geared to the scheduled time of each task, with more checks
made on the time-intensive tasks.  Milestones can be used as quality assurance
triggering devices In this regard.  When the program display indicates an
upcoming milestone for a task, the quality assurance coordinator can increase
his surveillance in that area-

     A quality assurace program applied to emission inventory project
scheduling would have three general types of procedures.  Standard operating
procedures would include organization planning, personnel training, project
planning, and the development of step-by-step procedures for technical tasks.
Techniques for finding and correcting inconsistencies and errors would include
identification of potential error sources, evaluation of the impact of these
sources, location of checkpoints for optimal problem detection, and a
provision for timely response when problems occur.  The determination of
product quality and reliability, In the context of an emission inventory, is
the same as data quality assessment.  These procedures include a periodic
review of the entire inventory process, the development of standards against
which to test the accuracy and precision of results, and a system evaluation
to maintain optimal resource efficiency.

     In summary, to ensure that agency manpower Is efficiently used In the
compilation of an emission Inventory, a project schedule should be developed.
This schedule should be based on known project tasks and estimated manpower
requirements.  A graphical presentation of the inventory tasks, their
estimated completion times, major project milestones, and manpower
reqviirements is a useful way of displaying and summarizing the project
schedule.  As the project is carried out, this graph can be revised, and
actual time requirements and completed milestones superimposed on the original
projections.  By continually tracking the progress of the overall emission
inventory effort in this way, management can (1) ensure that each task is
being expeditiously carried out, (2) revise Its manpower commitments to
reflect schedule changes, and (3) learn from its experience so that It can
apply this knowledge in future Inventory efforts.


                                        2-26

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References for Chapter 2.0

 1.  Southerland, J., "Emission Inventories:  A Perspective,"  Presented  at  the
     71st Annual Meeting of the Air Pollution Control  Association,  Houston,
     TX,  June 25-30, 1978.

 2.  "Report on Source/Emission Inventory Systems and  Data  Bases  for  the
     Standing Air Monitoring Work Group," (Unpublished),  U.S.  Environmental
     Protection Agency, Research Triangle Park, NC,  1978.

 3.  Procedures for Emission Inventory Preparation  - Volume II;   Point
     Sources, EPA-450/4-81-026c, U.S. Environmental  Protection Agency,
     Research Triangle Park, NC, September 1981.

 4.  Procedures for Emission Inventory Preparation  - Volume III:  Area
     Sources, EPA-450/4-81-026c, U.S. Environmental  Protection Agency,
     Research Triangle Park, NC, September 1981.

 5.  Procedures for Emission Inventory Preparation  - Volume IV;   Mobile
     Sources, EPA-450/4-81-026d, U.S. Environmental  Protection Agency,
     Research Triangle Park, NC, September 1980.

 6.  Manpower Planning Model, EPA-450/3-75-034, U.S. Environmental  Protection
     Agency, Research Triangle Park, NC, 1975.

 7.  Walsh, G. N. and D. J. VonLehmden, "Estimating  Manpower Needs  of Air
     Pollution Control Agencies," presented at 63rd  Annual  Meeting  of the Air
     Pollution Control Association, Paper No. 70-92, 1970.

 8.  Procedures for the Preparation of Emission Inventories for Volatile
     Organic Compounds,  Volume I, Second Edition, EPA-450/2-77-028, U.S.
     Environmental Protection Agency, Research Triangle Park,  NC, September
     1980.

 9.  Final Emission Inventory Requirements for 1982  Ozone State Implementation
     Plans, EPA-450/4-80-016, U.S. Environmental Protection Agency, Research
     Triangle Park,  NC,  December 1980.

10.  Compilation of Air Pollution Emission Factors,  Third Edition and
     Supplements, AP-42,  U.S. Environmental Protection Agency, Research
     Triangle Park,  NC,  September 1980.

11.  Source Assessment:   Synthetic Ammonia Production, EPA~600/2-77-107m, U.S.
     Environmental Protection Agency, Research Triangle Park,  NC, November
     1977.

12.  Industrial Process Policies for Environmental Use; Chapter 5, Basic
     Petrochemicals  Industry,  EPA-600/2-77-023e,  U.S. Environmental Protection
     Agency, Research Triangle Park,  NC,  January 1977.
                                      2-27

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13.   Procedures for Emission Inventory Preparation - Volume V;  Bibliography,
     EPA-450/4-81-026e, U.S. Environmental Protection Agency, Research
     Triangle Park, NC, September 1981.

14.   Shah, M. C- and F. C. Setherman, "A Methodology for Estimating VOC
     Emissions from Industrial Sources," Presented at the 71st Annual Meeting,
     American Institute of Chemical Engineers, Miami Beach, FL, November 1978.

15.   Bradley, R., J. Stredler, and H. Taback, "Improving Emission Inventory
     Quality - A QA/QC Approach," Presented at the 73rd Annual meeting of the
     Air Pollution Control Association, Montreal, Canada, June 22-27, 1980.

16.   Development of an Emission Inventory Quality Assurance Program,
     EPA-450/4-79-006, U.S. Environmental Protection Agency, Research Triangle
     Park, NC, December 1978.

17.   Goklany, I. M., "Emission Inventory Errors for Point Sources and Some
     Quality Assurance Aspects," Journal of the Air Pollution Control
     Association, 30(4);362-5, April 1980.

18.   Donaldson, T., and M. Senan, "Estimating the Cost of State Emission
     Inventory Activities," Presented at the 73rd Annual Meeting of the Air
     Pollution Control Association, Montreal, Canada, June 22-27, 1980.

19.   Moder, Joseph J., and C. R. Phillips, Project Management with CPM and
     PERT, Reinhold, New York, 1964.

20.   Shaffer, L. R., J. B. Ritter, and W. L. Meyter, The Critical-Path Method,
     McGraw Hill, New York, 1965.

21.   Kelley, J. E., Jr., "Critical-Path Planning and Scheduling:  Mathematical
     Basis," Journal of Operations Research Society of America, 9, 1961.

22.   Kelley, J. E., Jr., and M. R. foalker, "Critical-Path Planning and
     Scheduling," Proceedings of the Eastern Joint Computer Conference, 1959.

23.   POD and NASA Guide, PERT Cost Systems Design, Office of the Secretary of
     Defense and the National Aeronautics and Space Administration, U.S.
     Government Printing Office, Washington, D.C., 1962.

24.   Charnes, A., and W. W. Cooper, "A Network Interpretation and a Directed
     Subdual Algorithm for Critical-Path Scheduling," Journal of Industrial
     Engineering, 13, 1962.
                                     2-28

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                           3.0   APPLICATIONS  AND USERS


3.1  APPLICATIONS OF THE INVENTORY

     An accurate, comprehensive and current emission inventory of all sources
can be used for a variety of applications by the air quality control agency.
Proper planning and commitment of resources can help ensure that the emission
inventory includes all the information needed for the specific, localized
needs of the agency.

     The specific applications of emission inventory data are many and
diverse.  Some are set by federal reporting requirements, while others support
agency programs and services and are responsive to public concerns.  As the
compiler of the inventory, and the organization most responsible for its
maintenance, the local agency must design the inventory for its own individual
requirements.  Data obtained from each emission source must be processed,
stored and presented in a manner to reflect the priorities of the agency.

     All state and local air quality control agencies will have certain common
applications of emission inventory information.  In this section, the
principal uses of inventory data will be discussed.  These applications will
illustrate how inventory information provides essential input to many air
pollution control programs.  The applications will be discussed relative to
activities commonly found in most agencies.

     Planning and Development

          State Implementation Plan (SIP) preparation and review

     -    Strategies development

     -    Modeling

     -    Reasonable further progress (RFP)

     New Source Review

          Prevention of significant deterioration (PSD) and emissions
            offsets

     -    Environmental impact review

     Surveillance and Analysis

     -    Ambient monitoring network design

     Compliance

          Enforcement and compliance
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     Special Studies

          Trends

          Energy analysis

          Research

The applications listed above and discussed below are not intended to be all
inclusive but rather are presented to demonstrate how a well engineered and
prepared inventory can serve as a diversified management tool.

3.1.1  STATE IMPLEMENTATION PLAN (SIP) PREPARATION AND REVIEW

     State Implementation Plans (SIPs) are developed by state air quality
control agencies to ensure that the National Ambient Air Quality Standards
(NAAQS) will be met.  The plans are required by federal regulation* and
address several distinct activities within an overall air quality management
program.  These typically include ambient monitoring, stationary source
emission limitations, compliance schedules, transportation control plans, new
source review procedures, and the establishment of air quality maintenance
areas (AQMAs) among others.  Few agencies had detailed emission inventories at
the time the plans were initially prepared in the early 1970's.  Consequently,
agency management was forced to develop control regulations for source
categories without a. clear understanding of the actual emisssions from these
categories, or the affect each SIP control strategy would have in reducing
total pollutant concentrations.  The initial SIPs therefore had mixed success
in attaining ambient air quality goals.  When the Clean Air Act was revised in
1977, Congress recognized the importance of utilizing an emission inventory to
systematically assess and control ambient air pollutant levels.  SIP revisions
for areas which had not yet been brought into compliance are required to
provide for the preparation of a detailed emission inventory of that area.**
The reasons for this are clear—to reduce emissions, the sources and
quantities of emissions must be knowr-  All sources of emissions, including
the relatively easily identifiable major point sources, broad based area
sources, and the difficult to quantify fugitive emission sources must be
included.   Once this comprehensive inventory is established, management can
accurately assess the effect of new regulations.

     This use of an emission inventory to evaluate state regulations and SIPs
is as important in attainment areas as it is in nonattainment regions.
Management concern with attainment areas involves ensuring that air quality
will be preserved.  Normal growth in business activity will inevitably lead to
a growth in process emissions, and management must plan for this growth and
adjust its regulations accordingly.  New regulations promulgated on
 *Clean Air Act.  Section 110, 40 CFR 51—Requirements for preparation,
  adoption, and submittal of implementation plans.

**Clean Air Act, as amended, November 1977.  Section 172 (b)(4).
                                    3-2

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 this basis can be justified technically and will be more acceptable to  the
 affected industries and the public in general.

 3.1.2  STRATEGIES DEVELOPMENT

     Control strategies are adopted to bring noncompliant air quality regions
 into compliance and to ensure that regions of compliance retain good air
 quality levels.  Strategies are typically developed by an agency on a
 pollutant-specific basis.  The development of any strategy to limit emissions
 must use an emission inventory to provide information on the number, location,
 and size of emission sources, and one or more dispersion models to relate
 emission rates to air quality pollutant levels.  Since proposed control
 options are frequently expensive to implement, it is important that the
 evaluation of various control strategies be based on complete and accurate
 emission data.

     The various factors that go into development of a control strategy are
 presented schematically on Figure 3-1.   The emission inventory and control
 data identify for management the major sources of emission of a particular
 pollutant under investigation.  With this knowledge, management can formulate
 control strategies which affect one or more source categories and calculate
 the change in emissions due to each strategy.  For example, one control
 strategy to limit sulfur dioxide emissions might only affect emissions from
 large, point sources, while a second might concern itself with both point and
 area sources.  Data on all sources must be included in the inventory to
 provide a sound basis for the assessment of a variety of options and
 strategies.  For each strategy the inventory is adjusted to reflect the effect
 of the proposed regulation.  Once the effect of each strategy on total source
 emissions is ascertained, the resulting change in ambient air concentration
 levels must be determined by use of atmospheric simulation models.  The agency
 ultimately decides which strategy will best accomplish its goals after taking
 into account technical, economic and other factors.

     To evaluate various control strategies, an agency planner requires
 extensive data on the sources emitting a pollutant, including their location,
 the pollutant emission rate, the type of emission control, and many other
 source, process, and control equipment related parameters.  These data will be
 available from the inventory in the correct level of detail only if management
 has had the foresight to anticipate the need in prior inventory efforts.
 Management must recognize the potential utility of the inventory and ensure
 that all relevant source data are contained within the inventory.

 3.1.3  DISPERSION MODELING

     A dispersion model is a mathematical expression that predicts ambient
 pollutant levels based on source emission rates and meteorological data.
Models have been used in agency planning efforts to estimate the effect of the
 emissions of one source or a group of sources on ambient air quality.   As
 such,  they represent an integral part of such programs as air quality strategy
 development,  air quality maintenance area planning, new source review
 programs,  and the prevention of significant deterioration (PSD)
 determinations.  A number of air quality dispersion and simulation models have

                                      3-3

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 been developed.^»^  The models differ from each other in a number of ways.
 These include the number and type of sources they handle (point, area,  line,
 etc.). the spatial and temporal resolution of pollutant emission rates, the
 averaging time for which they estimate ambient concentrations, the number and
 type of pollutants for which they can compute average concentrations, and the
 manner in which they adjust for the topography of the area under
 investigation.  With so many variables involved, most models are only used in
 specific, limited applications.

     At a minimum, all models require substantial source data.  For a point
 source, these data include the location of the source, stack height and
 diameter, the velocity and temperature of the flue gas emissions, and the
 release rate of the pollutant emission.  The dispersion model will use  these
 data to predict ground level pollutant concentrations.

     Because of the many variables involved in the use of dispersion models,
 management must know not only if they are going to use. a model, but must be
 able to identify the specific model and its data requirements.  This is
 especially true with regards to the temporal resolution of pollutant emission
 rates.  Will an emission inventory that reports emissions on an annual basis
 be sufficient?  Should it be seasonal?  Monthly?  Hourly?  Management must
 either choose a model whose requirements are consistent with the level of
 detail of the inventory or upgrade the inventory to provide the additional
 information required by the model.

 3.1.4  REASONABLE FURTHER PROGRESS (RFP)

     A regulatory mechanism which Congress added to the Clean Air Act in 1977*
 is Reasonable Further Progress (RFP).  RFP utilizes annual changes in
 pollutant emission levels,  as reported by the emission inventory, to measure
 the success of the SIP in meeting its goals in nonattainment areas.   As such,
 it serves to verify that the control strategy adopted to bring a nonattainment
 area into compliance is accomplishing its objective.  Should RFP indicate that
 progress is not being made, the state agency can alter its SIP to include more
 extensive emission control regulations.   Reasonable Further Progress is
 notable in that it uses the emission inventory,  for the first time,  to measure
 the effectiveness of a state implementation plan.   The RFP mechanism implies
 that by planning for,  measuring,  and keeping track of reductions in an
 emission inventory, a state agency can ultimately bring areas into compliance.

     RFP consists of two parts.  First,  a schedule is developed which
indicates total pollutant emissions (in tons per year) for a base year and the
projected emission level in 1983  that the agency believes will result in
compliance for the nonattainment  area.   The 1983 target date has been set by
Congress.**  The purpose of this  schedule is to  verify that the emission
 *Clean Air Act, as amended, November 1977—Sections 171(1) and 172(b)(3).

**Clean Air Act, as amended, November 1977—Section 172(a)(l) and (a)(2).
                                      3-5

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reductions obtained are being accomplished at a reasonable and efficient rate
so that attainment by the prescribed time will take place.  The second part of
RFP involves tracking the yearly reductions in actual emission inventory
pollutant levels.  These reductions will come about as a result of the
increased controls mandated by the SIP in the nonattainment area.  These
annual incremental reductions are then compared with the predetermined
schedule to determine the success of the SIP in this area.  If the scheduled
reductions are not met, then the state agency must adopt additional measures
to reduce emissions.  These might include increased enforcement, a stricter
new source review procedure, or more stringent emission limitations-  The
entire mechanism of RFP schedules and tracking is explained in detail in
Reference 2.

     The use of an emission inventory in RFP schedules and tracking is
mandatory.  The inventory must be established for all sources which contribute
to the nonattainment pollutant.  Fugitive point and area source emissions can
be very significant but may easily be overlooked.  A true assessment of the
effect of emission reduction on air quality cannot be made if all significant
sources are not included in the inventory.

     The inventory must be updated on an annual basis.  Rather than make this
annual emission inventory a separate effort for nonattainment areas, state and
local agencies may decide to incorporate this work into an overall emission
inventory program for all areas within the agency's jurisdiction.  Sources in
nonattainment areas will be segregated, as required, through the use of an
area quality control region (AQCR) identifier code attached to the source
records in the emission inventory.

3.1.5  PREVENTION OF SIGNIFICANT DETERIORATION

     The Prevention of Significant Deterioration (PSD) is a congressionally
mandated policy* which is designed to protect the air quality in regions now
meeting National Ambient Air Quality Standards (NAAQS).  The method
established for preventing the significant deterioration of air quality is a
preconstruction review of large new plants whose emissions will affect regions
of the country that are currently complying with NAAQS.  The PSD rules apply
to a facility if (1) the plant is located in an area that is in compliance
with any NAAQS, (2) the potential emissions from the source of any regulated
pollutant exceeds 100 tons/year and the facility is in one of the 28
industrial categories listed in Table 3-1 (or for all other industrial
categories if the potential emissions exceed 250 tons/year), and (3) the plant
commenced construction on or after March 19, 1978.  If these criteria are met,
the facility is required to undergo a preconstruction review by the state air
quality agency.
*Clean Air Act, as amended November 1977—Sections 160-169.
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                     TABLE 3-1.  PSD INDUSTRIAL CATEGORIES
Fossil-fuel steam electric
  plants of more than 250 million
  Btu per hour heat input

Coal cleaning plants (thermal
  dryers)

Kraft pulp mills

Portland cement plants

Primary zinc smelters

Iron and steel mills

Primary aluminum ore reduction
  plants

Primary copper smelters

Municipal incinerators capable of
  charging more than 250 tons of
  refuse per day

Sulfuric acid plants

Nitric acid plants

Petroleum refineries

Lime plants

Phosphate rock processing plants
Coke oven batteries

Sulfur recovery plants

Carbon black plants (furnace
  process)

Primary lead smelters

Fuel conversion plants

Sintering plants

Secondary metal production
  facilities

Chemical process plants

Fossil-fuel boilers of more than
  250 million Btu per hour heat
  input

Petroleum storage and transfer
  facilities with a capacity
  exceeding 300,000 barrels

Taconite ore processing facilities

Glass fiber processing plants

Charcoal production facilities
Source:  40 CFR 51.
                                      3-7

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     The chief components of the PSD review Include (a) an area classification
system, (b) increments of air quality, and (c) best available control
technology (BACT).  The area classification system was established for all
clean air regions to allow a moderate amount of industrial growth in all areas
but not allow industrialization to degrade air quality to the point where air
quality standards were jeopardized.  All areas are classified Class I, Class
II, or Class III.  States can reclassify areas to allow for increased
industrialization with public approval.  Class I areas include the most
pristine areas of the country, such as many National Parks.  Facilities whose
emissions impact these areas are subject to the greatest emission control.
Class II areas are areas of moderate growth and Class III areas are areas of
major industrial activity.  Areas can only be designated Class III after a
public hearing.

     For each area classification,  PSD defines the increments of additional
pollutant (particulate and sulfur dioxide) that are allowed in an area due to
the effects of all new growth in that area.  These increments are shown in
Table 3-2.  As can be seen from this table, only small,  incremental increases
will be allowed in the Class I areas.  This will ensure that these existing
clean areas will maintain their relatively high level of air quality.   If an
area were to be changed to Class II, additional growth and a higher pollutant
increment would be permitted provided the NAAQS were not exceeded.

                       TABLE 3-2.  AIR QUALITY INCREMENTS


                                   Area designation            Primary ambient
                             	      air quality
        Pollutant3           Class I   Class II   Class III        standard
Particulate matter

  Annual geometric mean         5         19          37               75
  24-hour maximum              10         37          75              260

Sulfur dioxide

  Annual arithmetic mean        2         20          40               80
  24-hour maximum               5         91         182              365
  3-hour maximum               25        512         700            1,300
aAll units in micrograms per cubic meter.

Source:   40 CFR  51.
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      In specifying an incremental measure of air quality deterioration,
Congress, in the Clean Air Act, implied the use of dispersion modeling and
emission inventories.  Thus, sufficient data for dispersion modeling must
exist in the inventory for all sources, including new and modified sources.
Once  the source record is established, it can be used for additional emission
inventory related applications.  The PSD program, in fact, requires that the
agency keep close track of all sources that are applicable to PSD review.  The
agency must quantify the cumulative effect of all new sources on ambient air
levels.  The emission inventory should be used to store these new source
records, with some easily identifiable code assigned to PSD related sources.
As each new PSD source is reviewed, all similar sources can be extracted from
the inventory so that the net affect on ambient air quality of all sources can
be ascertained through the use of a dispersion model.

      To ensure that the increments are not quickly expended, the Clean Air Act
specified that each major new source install best available control technology
(BACT).  BACT is determined for each industry on a case by case basis and will
not be discussed in detail here (see Appendix A for a definition of BACT).
This  BACT requirement should be identified on the source emission inventory
record.

3.1.6  OFFSETS

     While PSD regulations are concerned with new construction in clean air
attainment areas, the Emissions Offset policy involves new construction or
substantial modification of facilities in nonattainment areas.  This policy
was originally issued by the EPA in its interpretative ruling* and
subsequently made a requirement of all SIP Revisions for nonattainment areas.**

      The Offsets policy essentially states that no major source can be
constructed in an area where there is a NAAQS violation unless it obtains a
permit.  This permit imposes stringent control requirements including emission
reductions or "offsets" that are larger than the emissions produced by the new
facility.  This program ensures that any major facility constructed in a
nonattainment area will "offset" more emissions than it will produce and the
entire airshed will see a net reduction in emissions due to the construction
of the new source.

     Since state agencies are charged with the administration of the Offsets
policy,  each state  will define which sources will be regulated.   Typically,
new sources with actual emissions exceeding 50 tons/year,  1000 Ib/day,  or 100
Ib/hr of particulate,  sulfur oxides, nitrogen oxides, volatile organic
compounds,  or carbon monoxide will be affected.
 *Federal Register 41,  December 21,  1976.  pp. 55524.

**Clean Air Act,  as amended,  November 1977.  Sections 172-173.
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     Imposition of the Offsets policy requires that the owner of a proposed
facility find a source where an emission reduction can be effected.  This may
be within his own plant, at another industrial facility, or at a government
facility.  The emission inventory is the most direct vehicle for identifying
the location and amount of emission reductions available from a source.
Management, however,  must plan its inventory data system to provide for this
capability.  In addition to the standard facility data stored in the
inventory, a space on each facility record must be devoted to actual or
potential emission offset.  Facilities which realize emission reductions due
to the closing down of a process or the installation of less polluting
equipment can then register these reductions with the agency.  These offsets
can be maintained within the inventory to expedite review procedures for major
new sources in nonattainment areas.

3.1.7  ENVIRONMENTAL IMPACT ANALYSIS

     Environmental Impact Analysis is a regulatory tool used to assess
potential environmental effects that result directly or indirectly from the
construction of new projects.  For projects involving federal funding, the
analysis is required by the National Environmental Policy Act (NEPA).*  Many
individual states have passed legislation which requires similar environmental
analysis for state-funded projects.  These environmental reviews are contained
in Environmental Impact Statements (EIS).  These statements must identify and
discuss the environmental effects of the proposed action and analyze and
compare alternatives.  The applicability of these reviews is not explicitly
spelled out in the law and is often decided by the courts.  Projects for which
an EIS is usually required include energy projects, dams, highway
construction, subsidized housing, shopping centers, and industrial park
developments.  An EIS must concern itself with all environmental factors
including air and water quality, solid waste generation and disposal, odors,
and ambient noise levels.  Only the air quality related aspects of an overall
environmental impact analysis will be discussed here.

     To review the effects of a new source on local air quality, an agency
must first determine ambient air quality levels at the project site using, if
available, data from local ambient monitoring stations.  The impact of the
project on these levels must then be determined.  To do this, source emission
data of the detail contained in an emission inventory must be obtained.  These
data should include not only pollutant emissions generated directly by the
project itself, but also increased emissions brought about by the projects
secondary impacts such as increased vehicular traffic and fugitive dust
emissions.  Once quantified, these pollutant mass emission rates are used with
dispersion models to predict the overall effect of the project on local
ambient air quality.   The use of a dispersion model in this application
establishes the amount and detail of emission data that are required.  In
addition, for impact analysis projects, the expected growth of emissions must
be estimated to determine the project's effect on long term air quality
*40 CFR 1500-1508.


                                      3-10

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 maintenance.  The quantification of all short and long  term pollutant
 emissions that is required for this review will also help agency management
 define any additional regulatory actions  (i.e., NSPS, NESHAPS, PSD, Offsets)
 that are applicable.  All relevant federal, state, and  local air quality
 regulations must be listed and the actual or projected  status of all
 pollutants determined.  If the project involves secondary impacts, these must
 also be quantified and added to the source's emission inventory record.
 Finally, fugitive emissions that may result from the proposed action must be
 calculated.  When completed, a comprehensive emission inventory profile or the
 proposed project will be available.  A similar source record must be developed
 for each proposed alternative that is addressed in the  impact statement.  When
 all emission related data have been quantified, the entire data set for each
 alternative is modeled separately to ascertain the effects on local ambient
 air quality.  The various inventory source records are  retained until the
 project is completed, and the source records for the selected alternative are
 added to the inventory.

 3.1.8  AMBIENT MONITORING NETWORK DESIGN

     The emission inventory can be used to design ambient air monitoring
 networks.  Ambient air quality monitoring is a vital element in state and
 local air quality programs to establish the compliance  or noncompliance status
 of state, county, or air quality control region with respect to NAAQS.^  The
 accuracy of the ambient air quality data that are obtained and the
 representativeness of the monitoring sites seriously impact on the usefulness
 of the agency's air quality control programs.

     The documentation of population exposure to ambient pollutant levels is
 the single most important aspect of an ambient monitoring network.  However,
 there are a host of agency programs which need monitor  data support.  These
 programs include those to:

     Evaluate ongoing and planned control strategies;

     Determine background concentrations;

     Develop or revise national control policies for criteria and other
     pollutants (includes New Source Performance Standards (NSPS), tall
     stacks, and Supplementary Control Systems (SCS));

     Provide data for model development and validation;  and

     Document pollution episodes and initiate episode controls.

     The establishment or optimization of  an ambient monitoring  network to
provide support for these programs is an important task for management.   The
design of this optimum network includes retaining representative existing
sites as well as selecting new sites.   As  this network will determine the
compliance status of the area,  it  must be  designed in accordance with federal
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requirements-*  Information which must be considered in this network design
include (1) existing and future plans for land use, (2) traffic counts and
other transportation data, (3) demographic statistics, (4) meteorological
data, (5) geographical information, and (6) existing air quality data-

     Geographical placement of the monitoring site to accurately determine
pollutant concentrations can only be accomplished by detailed analyses of
large amounts of background information for the area under consideration.
Emission inventory data are necessary input to an air quality dispersion model
which can be used to estimate the impact of sources on selected geographical
areas.  The selection of a model which is most appropriate for the area under
investigation will establish the level of detail that the emission inventory
must satisfy.  Specifically, the number of sources to be included, and their
spatial and temporal resolution will be set by this dispersion model.  The
predicted air quality impacts, in concert with demographic patterns, are then
used to select the monitoring sites which satisfy conditions for the maximum
number of agency programs.  The use of an emission inventory can also aid the
agency in siting monitors which measure the impacts of a few selected sources;
for example, to monitor the impact of facilities which have been allowed to
convert to a higher sulfur oil or coal, as part of a SIP revision.

     In cases where no dispersion model analysis is available, techniques do
exist for using only the emission inventory in the site selection process.
Methods such as the manual plotting of plumes downwind of major sources based
upon the prevailing wind direction are outlined in detail in the site
selection manuals published by EPA for the criteria pollutants.

3.1.9  ENFORCEMENT AND COMPLIANCE

     Agency enforcement and compliance activities have a direct dependence on
air pollution control emission inventory data.  These programs encompass a
variety of actions which concern themselves with individual emitters of
pollutants.  Items such as scheduled  annual source inspections, source
sampling, plant visits in response to ^.tizens complaints, and observed
visible emission violations require agency personnel to have a detailed
knowledge of a facility, its process operations, and its emission rates.
These data are Included in an emission Inventory and can be used to support
enforcement and compliance activities.  However, agency compliance actions
require additional data that are not normally kept in an inventory.  For
example, enforcement case histories and the establishment of compliance
schedules draw upon past inspection reports and notices of violation that are
not: normally maintained with the emission inventory.  Because there is such a
strong interaction between the inventory and compliance-related activities,
management must plan for the continued, easy exchange of data from one
activity to the other.
*40 CFR 58.
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     This exchange of information can work  both ways.   Compliance  activities
 that draw upon inventory data can also  serve to verify  and  update  that  data.
 New information on a source  that is obtained as a  result  of the  issuance  of a
 permit or the inspection of  a facility  should be included in the emission
 inventory.  This internal updating mechanism will  ensure  that the  agency  is
 utilizing the latest available source information.

     In spite of the inherent disadvantages an agency may face attempting to
 incorporate all source data, including  compliance  records,  into  one  control
 file, management may choose  this approach.  Agencies which  have  automatic data
 processing equipment can place some or  all  of their source  records on a
 computer.  One such system that is currently used  by many agencies in this
 manner is the Emission Inventory System.  This system consists of  the Emission
 Inventory System/Point Source (EIS/PS)^ and the Emission  Inventory
 System/Area Source (EIS/AS).'  It was developed by EPA  to integrate  emission
 inventory and permit data.   The computer programs  required  are maintained
 (updated) by EPA and the system is available to state and local  air  pollution
 control agencies at no charge.  Many individual state agencies have  their own
 computerized system which similarly combine emission inventory data  with  other
 internal agency program requirements.

 3.1.10  EMISSION TRENDS

     Emission trends, in conjunction with ambient air quality trends, enable
 management to adjust their planning and enforcement activities to changes in
 source pollutant emissions within an area.  The increases or  decreases in mass
 emissions may be plotted for any subdivision of the entire  Inventory; e.g.,
 specific "critical" areas, industrial categories, source  sizes,  etc.  When
 coupled with ambient air quality data,  emission summaries provide a  measure of
 the cause and effect relationship between local source  emission  rates and
 measured ambient pollutant levels.

     Emission trends analysis has historically played a role  in  evaluating
 pollutant control strategy selection.   In the case of pollutants with easily
 documented origins, such as  sulfur dioxide, emission inventory trends have
 been used to verify the effect of Imposing specific control strategies on
 actual ambient air quality levels.  This relationship can then be used in
 future planning and strategy development efforts.  For pollutants that have a
 diversified industrial origin such as hydrocarbons, emission  inventory trends
 also Indicate the success (or failure) of imposing tighter  emission  controls,
 although the correlation between reduced source emissions and measured
 pollutant levels may not be as easily definable or traceable.  For all
 pollutants,  trend analysis helps pinpoint those emission  sources or  categories
 that are growing faster than others.   Management can use  this  information in
 periodic revisions of implementation plans to avoid ambient air quality
violations.

3.1.11  ENERGY ANALYSIS

     Emission inventories play an Important role in energy analyses because
 they contain energy use data for all  stationary sources.  The  type of fuel
utilized by  a facility and the fuel ash and sulfur contents are recorded in

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the inventory and updated on an annual basis.  In addition, each facility that
is Included in the inventory is identified by one or more industrial
indicators.  The Standard Industrial Classification (SIC) Code classifies the
source by its industrial type (e.g., chemicals and allied products, primary
metal industries, etc.).  The Source Classification Code (SCC) identifies the
specific production processes used within the source and the size range of
this equipment.  These codes can be used by the agency to segregate individual
industries from the total inventory for the purpose of conducting an energy
analysis.  For example, if industry in an area wishes to convert its oil-fired
boiLers to coal firing, the agency can extract all potentially affected units
(e.g., boilers with capacities in excess of 100 million Btu/hr) from the
Inventory using SIC and SCC codes.  Annual fuel oil use can be tabulated from
these individual source records and estimates of ambient pollutant
contribution can be made for the entire category using emission factors to
determine changes in pollutant emissions resulting from conversion of oil to
coal.  For complex scenarios, energy use data can be used with dispersion
models to predict changes in ambient air quality levels.  The emission
inventory permits the agency to calculate the effect of any proposed energy
strategy and in certain areas may permit the agency to revise Its SIP to allow
the use of cheaper fuels without exceeding ambient air quality standards.

3.1.12  RESEARCH

     Emission inventories have played an Integral part in many air quality
related research efforts.  These investigations have been conducted by state
and local agencies, universities, private contractors, and the federal
government.  Their subjects have ranged from the local effects of one source's
emissions to studies which utilize emissions from all sources over a
multistate region.  The emission Inventory is the definitive source of data for
studies which attempt to correlate emissions with environmentally related data
such as population disease rates.  This use of the inventory to correlate
pollutant cause and effect relationships helps define national policies and
transcends its use in day-to-day agency programs.

     State and local agencies may use inventories for such purposes as point
source model validation or Industrial energy density comparisons.  Model
validation studies Involve applying comprehensive emission and meteorological
data to a dispersion model and recording the predicted air quality levels at
specific receptor points which are usually ambient monitoring sites.  The
measured ambient air quality at these sites Is then compared with the
predicted concentrations.  The difference between predicted and measured
values is an Indication of the accuracy of the model for the specific
application under Investigation.

     Research into the causes of an ambient air quality violation may prompt
an agency Into conducting an extensive review of emissions from sources in the
area surrounding the monitoring site.  These investigations begin with a study
of emission inventory data for all sources in the area and can progress to
investigations of additional emission related factors such as daily weather
patterns, traffic counts, street cleaning, and construction activity that are
not part of the inventory data base.
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     The  federal government,  its contractors,  universities,  and  independent
 organizations use state emission inventory data  to  support multi-state
 investigations.  For example,  the Northeast  Corridor Regional Modeling Project
 conducted by EPA (1980 to 1982) utilized emission inventory  data to  quantify
 the level of interurban transport of ozone in  the broad  area from Washington,
 D.C. to Boston.  Emission inventories for all  states in  the  study area were
 combined  to help develop and  validate a regional scale photochemical
 dispersion model to characterize pollutant generation and transport  through
 the northeast and to analyze  various oxidant control strategies.

     A similar study was undertaken by the Electric Power Research Institute
 (EPRI).   This organization in its Sulfate Regional  experiment (SURE)8
 focused on the nature of sulfur oxide behavior in the eastern United States.
 Extensive emission Inventory  data were collected from utilities  in an  attempt
 to derive a quantitative method for relating emissions from  the  electric power
 Industry  to regional ambient  air quality as measured by  sulfur dioxide and
 partlculate sulfate levels.

 3.2  USERS OF THE INVENTORY

     Emission inventory data  are potentially useful to anyone requiring
 information on air pollutant  emitting sources.   The source,  location,  type,
 and amount of pollutant discharge as well as the type of Industry, process
 rate, and energy consumption  of any facility or  group of facilities  can be
 obtained from standard inventories.  Through the use of  automated data
 processing equipment, source  data can be sorted  by any single identifier or
 group of identifiers, such that specific user oriented reports can be
 generated.  The list of actual emission inventory users  is therefore quite
 extensive and covers a wide range of public and  private  institutions.  A
 review of some of these users will serve to illustrate the extent of emission
 inventory use.

 3.2.1  STATE AND LOCAL AGENCIES

     The most common users of emission inventories are the state  and local air
 pollution control agencies.   Inventories represent an Integral part  of their
 control programs and are used continuously for a variety of  internal
 applications.  Emission Inventories provide technical support for the  range of
 agency programs that have been previously described in this  section.    The key
 factor in an agency's use of  the inventory is planning.  Management must plan
 the inventory for all potential applications and ensure that the  scope and
 detail of source information contained in the inventory are  sufficient for the
 intended applications.

     Other state and local agencies may use emission inventories  for their
 projects.  Planning agencies concerned with air emissions from a  new
 stationary source such as a power plant,  or a traffic-Inducing source  such as
a shopping center,  will consult inventory data prior to Issuance  of a  ruling.
Local conservation commissions require inventory input when examining  items
such as solid waste disposal proposals or industrial expansion projects.
Agencies concerned with health problems are likely to contact air quality


                                       3-15

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control agencies for information on major emitters of various pollutants.  All
agencies concerned with the effect of its actions or proposed actions on air
quality can make use of the emission inventory.  A comprehensive inventory can
also be used by the agency to evaluate the variety of decisions made by
others, Including adjoining states and federal agencies, which may directly
affect the state or local jurisdiction and Its people in a significant way.

3.2.2  CITIZEN USE

     Air quality control agencies are established to serve the general
population.  The agency protects the health of Its citizens and is ultimately
responsible to them.  Thus citizens have a right to know how the agency
functions, and what information is used to support agency actions.  Through
public hearings, citizens can participate in the agency's decision making
process.  Among the responsibilities the agency has to these citizens is to
allow them open access to emission data such as that contained in an emission
inventory.  The air quality control agency should serve these citizens by
maintaining an accurate and easily accessible emission inventory.

3.2.3  GOVERNMENT CONTRACTORS/INSTITUTIONAL

     Consultants and universities will use Inventory data primarily for
research efforts.  Their data needs are governed by the complexity of the
investigation and the requirements of any dispersion model to be used in each
study.  In this regard, they act much like the control agency in their data
needs and the level of detail required.

3.2.4  FEDERAL (NON-EPA)

     In addition to EPA, several federal agencies draw upon the source data
available in the emission inventory.  Their use for this data is commonly for
preparation of an Environmental Impact Statement.  Federal agencies are
required to file impact statements on new major construction under their
jurisdiction that could have a potentially adverse impact on the environment.
The air impact analysis section of these Impact statements draws upon emission
inventory data to quantify air quality levels.

     In addition, many federal agencies use emission inventory information in
miscellaneous internal studies.  The Department of Energy utilizes specific
energy user lists for general reporting purposes, summarizing energy use
patterns and providing energy use trend reports.  The Department of
Transportation utilizes mobile source information taken from the emission
inventory in its planning process for highways and airports.  The Department
of Housing and Urban Development will use inventory data in residential
heaiting studies.  The Departments of Interior and Agriculture can use
Inventory data for assessment of Industrial categories of concern to them.
Any governmental planning agency that must consider environmental affects of a
proposed action is a potential user of emission inventory data.  In order to
make environmentally correct decisions, they must have a reliable, accurate
source of air pollutant emission Information.  An accurate, current, and
comprehensive emission Inventory of all sources will provide these data.


                                       3-16

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References for Chapter 3.0

1.   Criteria for Approval of 1979 SIP Revisions, OAQPS 1.2-095, U.S.
     Environmental Protection Agency, Research Triangle Park, NC, September
     1978.

2.   Workshop on Requirements for Nonattainment Area Plans, OAQPS 1.2-103,
     Volume 19, U.S. Environmental Protection Agency, Research Triangle Park,
     NC, January 1979.

3.   Workbook for Comparison of Air Quality Models, EPA-450/2-78-028a, U.S.
     Environmental Protection Agency, Research Triangle Park, NC, January 1979.

4.   Turner, D. B., "Atmospheric Dispersion Modeling, A Critical Review,"
     Journal of the Air Pollution Control Association, 29(4):502-519, April
     1979.

5«   Guidelines for Air Quality Maintenance and Planning and Analysis, Volume
     XII;  Applying Atmospheric Simulation Models to Air Quality Maintenance
     Areas, EPA-450/4-74-013, U.S. Environmental Protection Agency, Research
     Triangle Park, NC, September 1974.

6.   The Emission Inventory System/Point Source User's Guide,
     EPA-450/4-80-010, U.S. Environmental Protection Agency, Research Triangle
     Park, NC, May 1980.

7.   The Emission Inventory System/Area Source User's Guide, EPA-450/4-80-009,
     U.S. Environmental Protection Agency,  Research Triangle Park,  NC,
     May 1980.

8.   EPRI Sulfate Regional Experiment;  Results and Implications; EPRI
     EA-2077-SY-LD, Project 862-2, September 1981.
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                         4.0   INVENTORY DATA REQUIREMENTS


      In order to formulate decisions  for pollution control  or  reduction
 strategy, some basic information concerning  sources  and emissions  is
 required.  The emission  inventory file serves as  the repository  for this
 information.  The amount of information and  the detail or resolution  of the
 inventory data should be consistent with the intended use.   However,  a
 comprehensive inventory, of the detail described  in  this manual, should be
 maintained by the agency to satisfy both regulatory  and functional
 requirements.  A goal of emission inventory  planning is to  obtain  and maintain
 within the inventory the level of source and emission data  that  is needed for
 all anticipated uses of  the inventory.  Air  quality  dispersion modeling, more
 than  any other agency activity, will  determine the level of  temporal  and
 spatial resolution of the data maintained in the  emission inventory file.
 Background documents on each  dispersion model should be consulted  to  determine
 the specific temporal and spatial resolution requirements of each.

      Automatic data processing is strongly  suggested to handle the large
 amount of data that are needed for the comprehensive inventory.-'-   Various
 programs can be initiated that will facilitate data  edit checks  and sort and
 report data according to desired pollutants, source  categories,  etc.

      It is not always necessary to conduct an inventorying activity that
 includes all of the criteria  pollutants.  Rather, one pollutant, for  a  number
 of reasons, may present a more serious problem than  another  and  be subjected
 to more detailed analysis.  Thus, the scope of a  specific agency program may
 require an inventory effort that can  be restricted to cover  only those  point,
 area  or mobile sources that are directly related  to  the pollutant  of
 interest.  This is possible for the pollutants, SOX, NOX, hydrocarbons,
 carbon monoxide, particulate  matter,  and lead which  are now  maintained  in the
 emission inventory file.  Additional  hazardous pollutants may  be of interest
 to the agency and, if possible, the inventory should be expanded to include
 these pollutants.

      The grouping of emission sources into categories is done  to identify the
major sources of emissions and assist in the development and assessment of
 control strategies.  At a minimum the agency should  be prepared  to report
 source and emission data from those categories shown in Table  1-1.  More
 detail is desirable and made  mandatory by regulation in many situations.

     The comprehensive inventory is comprised of  three types of  sources:
 point sources,  area sources,   and mobile sources.  Point sources consist of
 identifiable points of emissions that release pollutants into  the  atmosphere,
usually greater than 100 tons per year of any pollutant.  Area sources  consist
 of a number of smaller sources, not classified as point sources, which are
defined by geographic boundaries and engaged in a specific activity that
provides a means of estimating the collective emissions from the sources.
Mobile sources are nonstationary emission sources, including both highway and
off-highway transportation sources.  Emissions from mobile sources result from
fuel combustion and crankcase and certain other evaporative VOC emissions.


                                      4-1

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4.1  POINT SOURCES

     The point source is an individual, stationary source of emission that is
maintained in the point source file.  Emissions are the result of process
operations and a facility or plant may contain several emission producing
operations which can be vented to one or several point sources of emission.
The inventory of point sources can be considered to be much more accurate than
an area source or mobile source Inventory.  This accuracy is due to the detail
required for characterizing and analyzing the operations of each point
source.  Because more detailed information is obtained concerning the process
throughputs, process parameters,  and operating schedules, emissions can be
estimated more accurately and with greater geographical and temporal
resolution.

     Any source emitting in excess of 100 tons per year of any criteria
pollutant is generally considered a point source-  However, there is no
uniform use of that emission rate limit.  The higher the cutoff limit, the
fewer the facilities that are included in a point source inventory; a lower
limit would result in the inclusion of more sources.

     The point source inventory has three levels of complexity.  In order of
increasing complexity they are:  the plant level, which denotes a plant or
facility that could contain several pollutant emitting activities; the process
level, representing the unit operations of specific source categories; and the
point level, where emissions to the ambient air from stacks, vents, or other
points of emission are characterized.  Information concerning the preparation
of point source inventories is presented in Volume II of this series.2.

4.1.1  PLANT LEVEL

     The first step in preparing an inventory of point sources is to collect
information which identifies plants or facilities which contain one or more
point sources of emission.  Each plant identified within an area Is assigned a
plant number and It is further Identified by geographic descriptors such as
air quality control region, state, county, city, street and/or mailing address
and UTM grid coordinates (or latitude/longitude).  A plant personnel contact
should also be identified to facilitate communication and interaction with the
plant.  Additional information gathered regarding the facility are annual fuel
consumption, process throughput,  hours of operation, number of employees and
the Standard Industrial Classification (SIC) code of the plant.  SICs are
prepared and published by the Office of Management and Budget of the U.S.
Government.  A given facility will have only one SIC denoting the principal
economic activity of the facility.^

4.1.2  PROCESS LEVEL

     A plant can consist of various processes or operations.  Each process can
usually be Identified by an EPA source classification code (SCC) which has
associated with it an SCC emission factor to allow calculation of emissions
from specific process operations and equipment.^»•*
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     The Information necessary for the establishment of  an  inventory  at  this
level includes source identification information  (as previously  described  for
plant level); the periods of process operation  (daily, weekly, monthly,
annually); operating rate data, including actual, maximum and design  operating
rate or capacity; fuel use and properties data  (ash, sulfur, trace elements,
heat content etc.); and identification of all pollution  control  equipment  and
their associated collection efficiencies (measured  or design).

     Emission estimates should identify the estimation method used; e.g.,
actual stack sampling, material balances, emission  factors, engineering
analysis, or other estimation techniques.  All  assumptions, procedures,  and
analyses should be documented to provide sufficient information  for evaluation
of the procedures used and the resulting emission estimates-

4.1.3  POINT LEVEL

     Each stack, vent, or point of emission which meets  or  exceeds the
specified point source emission rate designation is identified as a point
source within a plant.  Information obtained from the point source inventory
level is utilized in the design, testing and application of mathematical
models for the correlation of air pollutant emissions with  ambient air quality.

     Basic information such as location (UTM Coordinates),  stack height of the
emission point, diameter of the stack, emission rate , method of
determination, gas exit velocity from the stack, the efficiency  of control
equipment, and emission rates during normal and upset conditions, are
parameters necessary for establishment of a comprehensive inventory and for
modeling programs.  For modeling, the precision required in specifying the
position of a source is partly related to the position of the receptor.  Some
dispersion modelers concerned with the impact of a point source  on nearby
receptors have asked that the location of point sources  be determined within
10 meters.

     Although such a high degree of precision in specifying location may only
be necessary in a limited number of applications, It is  recommended that the
location of point sources be reported with a resolution  of at least 100
meters.  This level of resolution represents that specified for  the existing
data In the National Emissions Data System (NEDS).

4.2  AREA SOURCES

     An area source represents many sources of emissions which are too small
to be classified as point sources and for which data are maintained
collectively in the area source inventory.   Although these sources may
individually emit only small quantities of  pollutants,  the collective
emissions may have a significant impact on air quality.   Mobile  sources are
regarded as area sources.   However, mobile  sources are inventoried separately
from stationary area sources.
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     The area source data file is needed to provide a record of source and
emission data for categories of sources that are small and too numerous (e.g.,
residential heating units) to include in the point source file.  Area source
emissions for a category are estimated by multiplying an emission factor by
some known indicator of collective activity for the source category which can
be correlated with emissions; e.g., fuel burned is the activity factor used
for home heating units.  The selection and structuring of area source
categories, in addition to providing a means for the collective estimation of
emissions from the category, determines the type and amount of data that are
maintained in the area source file and the usefulness of the inventory in
agency activities, such as assessing the effects of control measures.  Major
area source categories include fuel consumption, solid waste incineration,
process losses (e.g., evaporation of VOC), and miscellaneous emission sources
such as fires and windblown dust.  Emissions from miscellaneous sources can
predominate in many locations.  See Reference 6 for a more detailed discussion
of preparing the area source inventory.

     The area source inventory can be conducted at three levels as well.  The
normal inventory levels include the AQCR, county, and grid level.  The AQCRs
are areas determined by the Federal government for air pollution planning
purposes, while the county is defined by jurisdictional boundaries and the
grid level by a coordinate system for modeling usage.  An area source
inventory will require the use of apportioning techniques to allocate
emissions from the area for which data are available to the AQCR, county and
grids.

     Area source emissions data compiled at the county (or county equivalent)
level will provide sufficient spatial resolution for some uses of the
inventory.  County limits are logical boundaries for compiling an emission
data base for two reasons.  The first is due to the areawide nature of some
pollutant problems; e.g., photochemical oxidants are generally not a localized
problem, but rather, form after several hours, or in some cases, days as a
result of reactions among precursor pollutants emitted over broad geographical
areas.  Consequently, less spatial rebolution is generally required for
volatile organic compound (VOC) emissions than is necessary for the other
pollutants for which national air quality standards exist.  The second reason
for compiling emission inventories on a county basis is related to data
availability.  The county represents the smallest basic jurisdiction unit for
which various records are kept that are appropriate for use in developing area
source emission estimates.  Thus, because it provides sufficient resolution
for the less data-intensive source/receptor relationships, and because of the
convenience it affords the agency, the county is the optimum jurisdictional
unit for compiling inventories that will be used for such tasks as developing
an oxidant control strategy.-'-  Apportionment of pollutant emissions from
counties to grids, however, may be required for the dispersion modeling of
pollutants other than VOCs to help in identifying local problems and
developing solutions to those problems.
                                      4-4

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 4.2.1  AIR QUALITY CONTROL  REGION LEVEL

     The Clean Air Act and  its amendments directed  the Federal  government  to
 designate AQCRs for high pollution urban areas-  At present,  there  are  247 Mr
 Quality Control Regions In  the United States and its  territories.   Within  the
 50 states, the boundaries of the  AQCRs  tend to coincide with  those  of counties
 or states.  However, many AQCRs are both interstate and intrastate, depending
 on the activity and geography of  the area.  Portions  of as many as  four states
 may be included under the limits  of one AQCR.  The  boundaries for the AQCRs
 can be found In Title 40 of the Code of Federal Regulations.

     The data required for  an inventory on the AQCR level may be aggregated
 from summary statistical data of  the counties.  The estimation  of pollutant
 emissions is based on the use of  correlative factors  such as  total  fuel usage,
 number of residential units, or other aggregate information for the counties
 within the AQCR.  When the  AQCR encompasses only a  section of a county,  the
 data concerning that area will have to be apportioned from the  county total.
 Distribution functions based on population, dwelling  units, number  of
 commercial Installations, or other common factors are used to estimate  the
 fraction of county activity apportioned to the AQCR.

     In some cases, an emission inventory for pollutants may  need to extend
 beyond the jurisdiction of an agency.  For example, a metropolitan  area will
 often encompass a number of counties and may overlap  into several states,  as
 in interstate AQCRs.  In these instances the inventory efforts  of all of the
 agencies should be coordinated so that  the results will be interchangeable and
 useful to all groups involved.

 4.2.2  COUNTY LEVEL

     Sources of information at the county level, may  be provided by EPA
 documents, by local and regional  studies dealing with city, county, or
 statewide categories, and statistical data from various Federal, state,  or
 local agencies.  The necessary data are usually available on  a  countywide
 basis and provide an excellent foundation for an Inventory.   Statistical data
 for census tracts can be combined to calculate values for county level  usage.

     As at the AQCR level, emissions can be estimated by applying emission
 factors to indicators of source category activity levels.  These indicators
 will vary for each source category.  For example, stationary  source fuel
 combustion emissions can be estimated from fuel-use reports for user
 categories and incineration emissions can be estimated from population  data.

 4.2.3  GRID LEVEL

     In certain Instances for the purpose of dispersion modeling of area
 sources,  much finer geographical resolution will be required  than that
 available at the county level.   The UTM coordinate system is  commonly used  to
 impose uniform grid zones onto geographic areas to allow for  convenient
apportioning of county activity level and emission data to grid levels.
Again,  the apportioning of the data is performed using distribution functions
derived from population,  commercial/institutional,  Industrial and
 transportation information.

                                     4-5

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4.3  MOBILE SOURCES

     Mobile sources such as vehicles, aircraft, and railroads, are a
significant source of emissions (see Table 1-1).  They constitute an important
segment of the area source category and, as Is the case In this emission
inventory series, are often considered as a separate category distinct from
area sources.  However, in presenting methods for inventorying mobile source
emissions in Volume IV,^ and consistent with the methods discussed in AP-42,
only those emissions resulting from the combustion of the fuel used to power
the mobile sources and certain evaporative losses have been classified as
mobile source emissions.  Fugitive emission resulting for example, from the
re-entralnment of dust by vehicle travel over unpaved roads or the use by
aircraft of dirt airstrips, are treated as area source emissions In Volume
III.6

     The emissions from motor vehicles are usually calculated from total
vehicle miles traveled (VMT).  VMT data are obtained from traffic studies
conducted by local or state transportation agencies.  A VMT breakdown by
vehicle type, fuel, speed and other factor is used to account for the effect
of vehicle operation on emission rates*

     If measured VMT data are not available, the VMT for an area can be
estimated by one of several possible techniques.  Gasoline sales, for example,
can be used to compute VMT through the use of average factors for the number
of miles per gallon.  State gasoline sales tax data or published gasoline
sales data are sources of information for the determination of fuel
distributed.  Fuel sales can also be used to estimate off-highway source
activities by agricultural equipment, industrial and construction equipment,
or smaller gasoline-powered machinery and motor vehicles.  However, fuel sales
data are not useful for other off-highway sources.  Vessels and railroads
powered by several types of fuels, for example, do not necessarily use fuel in
the area of purchase and correlation factors other than sales must be used to
apportion emissions.  Aircraft emissions are inventoried by the relating
number of landing-takeoff (LTD) cyclee performed at an airport to emissions.

4.3.1  AIR QUALITY CONTROL REGION AND COUNTY LEVELS

     The mobile source, which is one category of area sources, is inventoried
at the AQCR and county levels by using procedures similar to those discussed
for area sources.  Where available, state and county traffic counts,
transportation studies, and national statistics are used with proper
distribution functions to determine the VMT within an area.  Because an AQCR
tends to encompass several counties, basic data are obtained from local and
county agencies and aggregated to the AQCR level.

     Aircraft activity is determined by LTO data for passenger, freight, or
military flights obtained from airport, county, or FAA studies.  Emission
factors are used to compute the quantity of pollutants released by LTO
activities.  Vessel emissions are computed by the quantity of fuel used and
emission factors for both port and underway activity.'
                                      4-6

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 4.3.2   GRID  LEVEL

     Distribution functions  based  on  various  transportation factors  are  used
 to apportion mobile  sources  to  grid area  for  dispersion modeling.  The
 apportioning factors used to allocate VMT and fuel consumption to  the proper
 grids can be based on  population,  vehicular activity,  the  number of  fuel
 suppliers, or other  considerations.   However,  not all  transportation emission
 sources can  be allocated accurately using the above apportioning factors.
 Traffic volume counts  are the most direct and accurate data for apportioning
 motor vehicle activity.  VMT information, if  available,  may also  be updated
 from fuel-use information within the  region.   Airport  emissions are  assigned
 to the grid  that contains the airport.  Railroad activities produce  emissions
 from both rail lines and railyards, and vessels produce emissions  both in  port
 and in transit.  Methods have been devised for allocation  of these emissions.

 4.4  TEMPORAL RESOLUTION

     Annual  emissions  data have been  gathered in most  inventory efforts.
 However, for certain agency  programs, greater temporal resolution  In the form
 of seasonal, daily,  or hourly emission data are required (hourly emission
 estimates are needed for several photochemical atmospheric  simulation
 models).  Definite seasonal  and diurnal variations in  emissions exist for
 certain source category/pollutant  combinations due to  changes  In both emission
 factors and  activity levels.  For  example, in addition to  an increase in
 gasoline consumption during  the summer months, evaporative  organic emissions
 from automobiles and gasoline handling and storage operations  (both  major
 contributors of organic emissions  in  urban areas) will Increase significantly
 at higher summertime temperatures.  Other sources (e.g., exterior  surface
 coating), will also produce  higher oxidant season emissions.   Conversely,  some
 sources will exhibit less activity and, hence, lower emissions  during the
 summer months.  Hourly variations  are also significant for  many sources; e.g.,
 mobile sources, space  heating, asphalt paving, and pesticide applications.^-

     The annual emission inventory can be adjusted to  reflect conditions that
 exist during the time  period of interest.  The basic provision  for adjusting
 the inventory includes identifying those  variables that Influence  emissions
 and substituting appropriate values that  reflect conditions  during that  time
 period.  As  noted, two of the major variables  are source activity  and changes
 in emission  factors due to temperature.   Changes in wind speed  or  the seasonal
 modification of a product (e.g., use of gasoline with a lower vapor  pressure
 in summer months) can also affect  emission rates.^

     The temporal resolution of emissions can  be determined  by  contact with  a
 source or by the use of technically rational  temporal apportioning methods
 developed for the categories subject to significant temporal variation in
 emissions.   Appropriate temporal adjustment is not usually  afforded  simply by
 apportioning annual emission rates into shorter time intervals.  Summertime
 emission rates for many sources cannot normally be estimated accurately by
 simply dividing annual emissions by four and  special adjustment techniques are
 desirable.   A time-dependent Inventory was used by EPA for  the  Regional Air
Pollution Study (RAPS) in St. Louis,  Missouri.8  Adjustment  techniques,  as
                                     4-7

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specified in the RAPS study, are dependent on the specific source category/
pollutant combinations under consideration.  The agency should become familiar
with these techniques and other technical developments for determining
emissions as a function of time.

References for Chapter 4.0

1.   Procedures for the Preparation of Emission Inventories for Volatile
     Organic Compounds, Volume I, Second Edition, EPA-450/2-77-028, U.S.
     Environmental Protection Agency, Research Triangle Park, NC, September
     1980.

2.   Procedures for Emission Inventory Preparation - Volume II:  Point
     Sources, EPA-450/4-81-026b, U.S. Environmental Protection Agency,
     Research Triangle Park, NC, September 1981.

3.   Standard Industrial Classification Manual, Office of Management and
     Budget, Washington, DC, 1972.

4.   AEROS Manual Series, Volume I, AEROS Overview, EPA-450/2-76-001, U.S.
     Environmental Protection Agency, Research Triangle Park, NC, February
     1976.

5.   AEROS Manual Series, Volume II. AEROS User's Manual, EPA-450/2-76-029,
     U.S. Environmental Protection Agency, Research Triangle Park, NC,
     December 1976.

6.   Procedures for Emission Inventory Preparation - Volume III;  Area
     Sources, EPA-450/4-81-026c, U.S. Environmental Protection Agency,
     Research Triangle Park, NC, September 1981.

7.   Procedures for Emission  Inventory Preparation - Volum IV:  Mobile
     Sources, EPA-450/4-81-026d, U.S. Environmental Protection Agency,
     Research Triangle Park, NC, September 1981.

8.   Regional Air Pollution Study.  Emission Inventory Summarization,
     EPA-600/4-79-004, U.S. Environmental Protection Agency, Research Triangle
     Park, NC, January 1979.

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                     5.0   EMISSION  INVENTORY  DATA COLLECTION
     The major steps in the process of establishing the inventory data base
involve:

     Establishing a list of point, area and mobile emission sources,

     Contacting each point source to obtain quantitative process and emission
     data,

     Collecting activity level data for area and mobile sources, and using
     this data to develop emission estimates,

     Analyzing data to determine if all necessary data are available and
     technically satisfactory,

     Filling in any data gaps that exist in the emission data base by
     recontacting point sources or contact with new sources of activity level
     or emission data,

     Processing the data (including establishing source pollutant emission
     rates) for use in automated data processing equipment,

     Editing and validating the processed data, and

     Providing for periodic inventory maintenance and updates.

Because the data needs for each inventory effort will vary, there is no one
"best" way to effectively collect all needed emission inventory data.  Data
collection methods for an urban hydrocarbon inventory involving hundreds or
thousands of sources, for example, will be different than that for a local
inventory of vinyl chloride manufacturers.

5.1  INFORMATION SOURCES
     In order to ensure that all emission sources are included in the emission
inventory, a systematic approach must be used for obtaining this information.
Traditional sources of point, area,  or mobile source data should be used
initially to draw up source lists.   These sources include:

     Point Sources

          State Departments of Commerce and Labor

          State Permit/Registration  Files

          State and Local Industrial Directories

          State and Local Tax Offices
                                      5-1

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          Dun and Bradstreet, Industrial Directory

          Standard and Poors, Register of Corporations

          Thomas Register

          Local Directory of Manufacturers

          Regional Planning Commissions

          Trade and Professional Societies

     Area Sources

          State Agencies

          Regional Planning Commissions

          Annual Housing Survey—Bureau of the Census

          Statistical Abstract of the United States—Bureau of the Census

          Mineral Yearbook—Bureau of Mines

          Census of Agriculture—Bureau of Census

          Census of Retail Trade, Area statistics—Bureau of the Census

          Energy Data Reports—Department of Energy

          FAA Air Traffic Activity

          Other Statistical Government Publications

     Mobile Source

          Highway Statistics—Federal Highway Administration

          Vehicle Mile Traveled Data—State Department of Transportation

          Regional Planning Commissions

The value of each of these sources, many of which are statistically compiled
for states and counties, are discussed in other volumes of this
Series. >2>3  Collectively, these references will provide much of the basic
data for compilation of source and emission data, particularly  for  area and
mobile sources, within the inventory file.
                                    5-2

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5.2  DATA COLLECTION

     For a point source, the name and address and the telephone number of
responsible plant personnel should be obtained for each facility when
establishing a comprehensive listing of sources-  This information should be
provided by the facility when it completes and returns an emission inventory
questionnaire to the agency or completes facility permit applications.  For
inventory efforts that involve a limited number of sources, a telephone call
or visit to each facility can be made.

     In the case of area and mobile sources the agency is not required to
contact emitting sources.  Emissions are calculated using activity levels
(e.g., fuel consumed by the residential sector, vehicle miles traveled, and
aircraft landing and takeoffs) and emission factors developed for specific
source categories,  travel modes, etc.  Activity levels are obtained from
statistical sources of information:  normally, federal and state agencies;
suppliers of fuel or other activity-related process feedstocks, (e.g., dry
cleaning or degreasing solvents and retail paints); and state and local
agencies engaged in activities such as transportation, land use planning and
energy.

5.2.1  QUESTIONNAIRES

     The preferred method to obtain emission-related data from large numbers
of sources is the questionnaire.  Questionnaires can take many forms, from the
one page sheet directed at a specific industry (i.e., service stations) to a
multipage effort mailed to large, complex manufacturing plants.  A great deal
of effort has been devoted to the development of a questionnaire that
satisfies all data needs, and that can be accurately filled out by industry.
A standard questionnaire, the Air Pollutant Emission Report, has been
developed by EPA in response to this need (EPA Form 3520-4A (9-78)) and is
included as an appendix to Volume II of this Series.    Agencies planning to
develop their own questionnaire should consult an EPA publication entitled
"Development of Questionnaires for Various Emission Inventory
     The emission inventory questionnaire has three basic elements:  the cover
letter, the instructions,  and the questionnaire itself.  To ensure that the
questionnaire receives the prompt attention that it deserves, the cover letter
should include the following: 5

     Identification of the regulatory requirements which necessitate
     completion of the questionnaire by the facility and the penalties
     incurred by noncompliance

     A statement of the purpose of the questionnaire

     Provisions for confidentiality, if applicable

     A date for return of  the completed questionnaire
                                      5-3

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     The name (and telephone number) of a person within the agency to contact
     for assistance in completing the questionnaire

Figure 5-1 presents a typical format for a cover letter.  Although a key
element in the cover letter is the statement concerning the applicable
regulations and potential penalities for failure to respond, the agency should
foster cooperation rather than emphasizing penalties for noncompliance.

     Questionnaire instructions should be comprehensive enough to adequately
explain how to answer the questions.  If the questionnaire is a general one
designed to be applicable to all industries, the instruction sheet should
delineate which sections or pages should be completed for specific processes
or facilities.  Figure 5-2 presents a typical general instruction sheet.  If
the responses to questions are designed for direct coding to computer input,
the instructions should explain how to enter numbers properly.  An instruction
sheet that explains how the process flow schematic is to be presented must
also be included.

     The questionnaire itself will contain two sections, a general information
section and a process details section.  The general information section
identifies and locates the facility and solicits emission and activity level
data for the facility as a whole.  The process details section covers the
specific operations at the facility and solicits information on equipment,
activity levels, and emission points for each process.  The following
information is typically requested (or is to be verified) in the general
Information sections.

     Facility name, location and mailing address

     Facility plot plan showing location and identification of emission points

     Other identifying information, including facility operating schedules,
     number of employees, SIC code and plant UTM coordinates

     Person designated as plant contact for air quality-related questions

     Confidentiality, if desired, and a detailed justification of the reasons
     why specific information should be so classified

Whenever possible, all known information should be filled In by the agency
before the questionnaire is mailed.  This serves to minimize the time required
by the facility to complete and return the questionnaire.  The facility is
directed to correct any errors in the information entered by the agency.

     The process details section solicits information needed for the
characterization of emissions from all sources within the facility.  The line
of questioning here should proceed from information that is generally known by
the facility, that is, from the identification of emission processes and
equipment, to the more obscure data on specific pollutant emission rates.
This section usually requests some or all of the following information:
                                     5-4

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                          (OFFICIAL STATIONARY HEADING)
         LAWS OF THIS STATE  REQUIRE  THAT THE  INFORMATION REQUESTED BELOW
                   BE SUBMITTED AS SPECIFIED TO THE (AGENCY).
                       FAILURE TO RESPOND COULD RESULT IN
                  (LOCALLY APPLICABLE  REGULATIONS  OR PENALTIES)
Gentlemen:

     The  (agency) is conducting an inventory of atmospheric emissions of
organic compounds from stationary sources in (area).  The results will be used
in the formulation of control plans as required by (applicable regulations).
You are requested to provide information necessary for the assessment of
emissions from equipment and processes in your plant by completing the
enclosed  questionnaire.

     Please mark clearly any information, other than emissions data, which you
consider  confidential and include your reasons for doing so in your cover
letter.   In accordance with (state statutes) your claim for confidentiality
will be evaluated and you will be notified of the decision regarding  the
validity  of your claim.  In the event of a decision not to grant
confidentiality, you will have the right to appeal in accordance with (state
statutes).

     This questionnaire has been designed specifically for your industry;
therefore, you should answer each question.  If the space provided is not
adequate, feel free to either copy the form, request an additional copy, or
use a separate sheet.

     The  required data should be submitted no later than (date).   A return
envelope  is included for your convenience.  Any questions regarding this
questionnaire should be forwarded to (name of Agency personnel) at (phone
number).  Your cooperation and prompt response will be appreciated.

                                        Sincerely,
                                        (Name)
                                        (Title)
          Figure 5-1.  Sample format for a questionnaire cover letter.
                                      5-5

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                                   (SAMPLE)
                              Ci'.N! RAL INSTRUCTIONS
                     ORGANIC SOI.Vr.NT SOURCF. QUKSTIONNAIRK


1.   All questions should be directed to (name of agencv contact) (phone
     aumber).

2.   This questionnaire  was designed to obtain information from a wide variety
     of solvent user'.,.   The complete questionnaire me hides the following
     pages:

          Page A - General  Information
               R - Degreasing Operations
               C - Dry Cleaning Operations
               D - Protective or Decorative Coatings
               E - Fabric or Rubberized Coatings
               F - Miscellaneous Surface Coatings
               G - Ovens
               H - Printing
               I - General  Solvent  Use
               J - Bulk  Solvent Storage
               K - Control  and Slack Information

     You have received onlv the pages that our records show would pertain to
     your operations.   All  recipients should complete pages I, J, and K.  If
     certain pages appear to be missing please contact (name' of agencv contact).

3.   Data should reflect calendar vear (year) or (>ear), whichever is more
     readily available.   Specif)' any other 12-month period that may be used.

A.   Fill in the descriptive information and amounts of solvent use or solvent
     containing materials for each  device' opera Lin/, under countv permit  as shown
     in the  example on each page.'.  (Note:  these examples are tor illustration
     only and may not  represent actual operating conditions.)  If data are not
     available on an individual device basis, use best est imates from total
     plant usage.

5.   If the  type(s) and/or  percentages of solvents in coatings, inks, etc.. are
     not known, include  sufficient  information on the manufacturer,  tvpe and
     stock number so that this breakdown can be obtained.  A cony ol  the sup-
     plier's invoice would  be adequate.  Do not simply specify that  the  material
     meets Rule 66 requirements,

6.   Confidential or proprietary information mav be so specified by including
     a cover letter with the returned questionnaire.   The data that  will be
     generated during this  program wi 1 1 be public  informal ion.  However  tin-
     data on specific sources will  be presented in a m.mn''t  that will conceal
     the individual emission source to all but staff personnel.  It  is our
     understanding that  the data will not be used for enforcement purposes;
     however,  it must be recognized that this information 'nav In- emp loved in
     the formulation of  regulations which mav ul' imately al I CM t the spec" i I ic
     sources included  in the study.   Specify in writing  what  data  are
     considered confidential or proprietary.
 Figure 5-2.   Sample of questionnaire  general instruction sheet.

                                    5-6

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     Process flow diagrams with equipment descriptions

     Activity levels for sources of emissions

     Operating schedule of process/equipment contributing to emissions

     Control system descriptions

     Efficiency of control systems

     Stack data

     Emission rates from stacks, vents, and fugitive sources

     Stack emission test results and test conditions

     Physical and chemical characteristics of emissions

Some general rules for formulating questionnaires are:

     1.   Ask the right questions—those which solicits information that the
          agency needs to estimate emissions from the facility;

     2.   Be brief—questions that are short and to the point are easier to
          understand and will encourage facility response; and

     3.   Use multiple choice questions or check boxes when possible—they
          also facilitate response and are especially useful if the
          questionnaire is formatted for computer input.

Because some facilities will need special help with the preparation of
questionnaires, the agency must plan to provide such assistance.  In addition,
to develop a comprehensive emission data base, an organized follow-up program
should be conducted by the agency to ensure return of all questionnaires.

The returned questionnaire is a part of the documentation or the emission
inventory.  It is retained on file as documentation along with records of all
followup recontact information.

5.2.2  FILLING DATA GAPS

     Returned questionnaires, facility interview reports or statistical data
for determining area and mobile source activity levels and emissions must be
thoroughly reviewed by agency personnel.  This review will include checking
the questionnaire for missing or questionable information, follow-up contact
to obtain unreported information or to clarify questionable responses, and an
in-depth technical analysis of the collected data to ensure its validity.  The
most direct and productive method of filling point source data gaps is with a
follow-up phone call.  This personal contact is especially effective if the
data gaps are not extensive in scope.   Otherwise, a second mailing to all
                                      5-7

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delinquent questionnaire recipients will be required.  Ideally, all incoming
source data will be checked and follow-up activities conducted by agency
personnel familiar with the specific industry.  Questionable data due to
misinterpretation, errors in transcription, or erroneous assumptions by the
sources can, therefore, be quickly noted and follow-up evaluations conducted.
All data received must be tabulated and/or transcribed into a format that will
allow assessment of the adequacy of the data and entry into the data file.
Area source data concerning activity levels and emissions must also be
subjected to a quality assurance program.  In addition to routine checks for
transcription and calculation errors, data sources and procedures should be
evaluated.  Information used to estimate area source activities and emissions
should be calculated, if possible, using alternative data sources.

5.3  CALCULATION OF EMISSIONS

     The facility will be requested to report pollutants emitted and the
emission quantities for each.  The measurement method used for determining
emissions should also be Identified by the facility.

     Emission data from the facility must be carefully assessed by agency
personnel to ensure that all procedures used and process conditions maintained
during the test program were consistent with the obtaining of representative
data.  In the absence of data on source emissions, agency personnel must use
engineering judgment and knowledge of the specific process to quantify
emission rates.  Technical references relative to the process or similar
processes can be consulted to aid in this determination.  (See References 1 2,
3, and 6 for identification of some of the more useful publications relating
emissions to process design and operating parameters.)

     There are a number of methods currently used for establishing emission
rates, which include:

     1.   Stack emission tests

     2.   Process material balances

     3.   AP-42 emission factors6

     4.   Other emission factors

     5.   Guess (educated or otherwise)

     Stack tests provide the most accurate measure of process emissions, if
properly conducted during a period which is generally representative of
average annual operating conditions.  Process material balances, in certain
cases, provide a reliable measure of mass emissions.  A commonly used example
of this method is sulfur oxide emissions from oil-fired boilers.  Since
virtually all the sulfur contained in fuel oil is converted to sulfur oxide,
emissions can be calculated knowing the fuel firing rate and fuel sulfur
content.  Similarly, in certain instances, one can estimate uncontrolled
process solvent emissions if the solvent feed rate, final product solvent
percentage,  and process production rates are known.

-------
      In most situations where source test information is  not  available  or
material balances are not technically viable, the usual method  of determining
pollutant emissions for a given source type is to make generalized estimates
of typical emissions from these sources using emission factors.  Emission
factors estimate the rate at which a pollutant is released to the atmosphere
as a  result of some process activity.  Emission factors for each source
category have been derived from emission tests, material  balance calculations,
and other analytical techniques applied to sources within that  category.
While the emissions calculated using these average values may differ  from
actual emissions for a specific facility, overall they provide  a relatively
accurate estimate of pollutant release rates for the source category  under
consideration.  EPA's AP-42, is the most comprehensive listing  of emission
factors currently used.

5.4   DATA ASSESSMENT AND QUALITY ASSURANCE

      In order to ensure that all source data collected for the  emission
inventory are accurate and have been correctly transcribed onto computer input
cards (when automatic data systems are used), data validation procedures must
be used.  These procedures are designed to ensure that source identifier and
process information, such as UTM coordinates and stack data,  as well  as actual
source emissions levels, will be checked for errors or values that are
atypical of given sources.  For automated systems, this validation procedure
essentially consists of two parts.  An edit check is first run  on all
keypunched cards.  This check will identify cards that are incorrectly  coded
or left blank without an explanation.  This step helps to sort  out simple
clerical and keypunch errors.  The source record cards are then checked to
ensure that all data fall within prescribed limits set by the agency  for major
source categories.  A typical set of these checks for boiler  data is  shown in
Table 5-1.  This validation procedure will automatically  reject data  points
that  are beyond the limits normally found for that item.  Should the  data as
initially reported prove correct, it can easily be reinserted.  Similar
validation techniques are used to check emission inventory data which are
compiled manually.  Maximum and minlaium values of certain emissions and
process parameters by SCC, used by the National Emissions Data  System,  are
available from EPA's Office of Air Quality Planning and Standards, Research
Triangle Park, NC  27711.

      Typical emission inventory errors are presented in Table 5-2.  This list
is not exhaustive but does highlight commonly found problems.   In order to
minimize the quantity and impact of errors on emission inventory reliability,
a quality assurance procedure should be initiated each time an Inventory
effort is conducted.  Quality assurance/quality control techniques can  be
applied throughout the Inventory program from planning to reporting to  ensure
that  potential errors are minimized.  These techniques can be classified as
either preventive or corrective.''  Preventive techniques  are  those that are
applied as part of the inventory planning procedures.  Some common preventive
techniques,  e.g., classroom instruction for personnel and the establishment of
a specific emission inventory reference library,  are shown in Table 5-3.  Many
of these techniques are already an integral part  of most  inventory processes.
Others can be easily incorporated with few changes in normal agency procedures.
                                      5-9

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     Corrective techniques are those that are implemented to detect errors
that cannot be eliminated by preventive measures.  The data validation and
edit procedures previously mentioned are examples of corrective action control
techniques.  Some of these techniques, listed in Table 5-4, reduce random
errors such as digit transposition.  Another purpose, however, is to detect
deficiencies in the emission Inventory process.  The techniques can provide
useful feedback to the task planners and can provide a basis for improving the
preventive control techniques.  It is imperative that all errors, whether
detected by techniques such as these shown in Table 5-4 or by users, source
inspectors or other agency personnel, be documented in writing.  Standard
corrective action forms must be used and mechanisms provided to ensure that
the corrective actions are instituted and effective.'

     The appointment of one individual to act as quality assurance coordinator
will help to ensure that all control techniques will be implemented once they
are identified.  The coordinator can independently audit the emission
inventory process to ensure that errors in all phases of preparing the
inventory are detected and corrected.  This individual will serve as the focal
point for all quality assurance problems and corrective actions.  The
development of an effective quality assurance program rests upon a sound
assessment of system procedures and data quality, identification of potential
sources of error, and the development of techniques for detecting errors as
well as controlling them.

5.5  EMISSION INVENTORY MAINTENANCE AND UPDATE

     The compilation of an emissions inventory is a continual process.  The
inventory organization must monitor and record changes in the total number of
sources as well as changes in the operation of existing sources.  Maintenance
and updating of the inventory ensures that users are applying the most recent
data and can have confidence in the information provided.  In addition,
recently promulgated Federal programs, such as Reasonable Further Progress
requirements discussed in Chapter 3, require that inventories be upgraded
annually and total emissions calculated to demonstrate progress toward meeting
national ambient air quality levele.

     The need for periodic inventory maintenance and update is attributable to
several causes.  During the period of a year, some facilities will deactivate
process equipment or close completely.  New facilities and processes at
existing facilities will come online.  Existing plants may also increase or
decrease their production schedules or modify product lines and virtually all
facilities must revise their fuel use and process throughput data as these
figures change annually.  Population and land use changes that effect area and
mobile source pollutant emissions will also require inventory updating.
Updated regulations and emission factors may indicate the need for further
changes in the data file.

     The mechanism for carrying out maintenance and update efforts vary among
inventory systems.  Emission inventories that are maintained manually, with
only a paper record kept of all data, need only have specific data items
changed.  Care should be taken with these systems, however, to preserve the
                                  5-14

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5-15

-------
modified or updated information for reference purposes.  Computerized systems
vary in the ease with which data can be modified, but are updated in
essentially the same manner.  The new or revised data are placed on
standardized computer forms and inserted into the file.  A computer program
then transposes this new data onto the existing source record.  If the
computerized inventory system has no mechanism for storing modified or deleted
information, it is recommended that tape records or a paper copy of all
historical source data be maintained at the agency, again for purposes of
reference.

References for Chapter 5.0

1»   Procedures for Emission Inventory Preparation - Volume lit  Point
     Sources, EPA-450/4-81-026b, U.S. Environmental Protection Agency,
     Research Triangle Park, NC, September 1981.

2»   Procedures for Emission Inventory Preparation - Volume III: Area Sources,
     EPA-450/4-81-026c, U.S. Environmental Protection Agency, Research
     Triangle Park, NC, September 1981.

3.   Procedures for Emission Inventory Preparation - Volume IV;  Mobile
     Sources, EPA-450/4-81-026d, U.S. Environmental Protection Agency,
     Research Triangle Park, NC, September 1981.

4.   Development of Questionnaires for Various Emission Inventory Uses,
     EPA-450/2-78-122, U.S. Environmental Protection Agency, Research Triangle
     Park, NC, March 1979.

5.   Guide for Compiling a Comprehensive Emission Inventory (revised),
     APTD-1135, U.S. Environmental Protection Agency, Research Triangle Park,
     NC, December 1978.

6.   Compilation of Air Pollution Emission Factors, AP-42, U.S. Environmental
     Protection Agency, Research Triergle Park, NC, December 1980.

7.   Development of an Emission Inventory Quality Assurance Manual,
     EPA-450/4-79-006, U.S. Environmental Protection Agency, Research Triangle
     Park, NC, December 1978.
                                      5-16

-------
                  6.0   PRESENTATION  OF  INVENTORIES/DATA SYSTEMS


     The diversity of applications for which an emission inventory can be used
has resulted in a variety of methods for data presentation-  Specific display
methods are dependent upon many factors including the type and amount of data
required, the purpose of the data summary, and the audience to which the
summary is directed.

     The basic "unit" of emission inventory data is the individual source
record.  Typical source records are presented on Figure 6-1, for the
Federally-sponsored Emission Inventory System-'- (EIS) and Figure 6-2 for a
computerized state inventory system (New York AIR-100).  These source records
contain all relevant source and emission point identifiers.  Complete emission
inventory reports, containing one such record for each emission point,  are
typically used by state and local agencies in their source-oriented
activities, such as enforcement inspections and plan reviews.  For other
studies, source data summaries, focusing on one or more source identifiers,
can be compiled.  These identifiers can generally be placed into the following
four categories:

     1.   Source Category

               All facilities

          -    Individual emission points

          -    SIC (common industry)

          -    SCC (common process)

          -    Area sources

          -    Mobile  sources

          -    Fugitive sources

     2.   Geographical Category

          -    National

               State

          -    County

               AQCR

               AQMA

          -    Other  (defined for  specific projects)
                                    6-1

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                                                    6-3

-------
     3.   Pollutant Category

          -    Individual criteria pollutants

               All criteria pollutants

               Special (NESHAPS, Reactive VOC, etc.)

     4.   Other

          -    Energy use (by fuel)

          -    Control device application

     Data summaries are usually compiled relating these Identifiers.  For
example, lists may detail the major particulate-emltting facilities within an
AQCR; all facilities within a state that use asbestos and have an SIC code of
3293 (gaskets, packing, and sealing devices); or all facilities that consume
more than 100,000 tons of bituminous coal per year.  Once the specific data
requirements of a project are defined and the appropriate data summaries are
obtained from an. agency's emission inventory, the data must be presented in an
appropriate format.  The following subsection Illustrates various presentation
techniques.  Many of the examples shown are taken from EPA reports and reflect
national emissions; however, the techniques shown are useful to the reporting
aspects of state and local air pollution problems.

6.1  PRESENTATION TECHNIQUES

     The most common method of presenting emission Inventory data is the
tabulated summary.  Figures 6-3 through 6-5 present examples of this display
technique.  A second major presentation technique is the pie chart.  This
method, like all graphical displays, Is often useful when presenting data to
those who do not have the time and/or expertise to interpret detailed tabular
summaries.  Figures 6-6 and 6-7 are twj examples of pie charts used to present
emission Information.  Pie charts present component data as a percentage of
the whole and, therefore, are useful for representing the relative
contribution of various emission source categories In a given area.  Figure
6-6, for example, presents the relative contribution of each of the major
pollutants to total criteria air pollutant emissions in the United States.
Sulfur oxides and nitrogen oxides are singled out in this chart, as these data
were used in a presentation concerning the acid rain problem.  Figure 6-7
presents the relative contribution of various categories to total volatile
organic compound (VOC) emissions.^  Without describing actual emission
levels, this chart identifies the major source categories (bulk petroleum
storage and degreasing) and their contribution to total emissions.  Pie charts
simplify the comparison of emission data from various sources by concisely
summarizing large amounts of Information that may occupy several pages of
tables in a report.

     The time series of chart represents another graphical display technique,
Figures 6-8 and 6-9.  These charts displays changes over time of one or
several components, and are often used In emission trend reports.  Knowledge

                                       6-4

-------
Source category
Transportation
Highway vehicles
Non-highway vehicles
Stationary fuel combustion
Electric utilities
Industrial
Residential, commercial, and institutional
Industrial processes
Chemicals
Petroleum refining
Metals
Mineral products
Oil and gas production and marketing
Industrial organic solvent use
Other processes
Solid waste
Miscellaneous
Forest wildfires and managed burning
Agricultural burning
Coal refuse burning
Structural fires
Miscellaneous organic solvent use
Total
TSP
1.1
0.8
0.3
4.8
3.4
1.2
0.2
5.4
0.2
0.1
1.3
2.7
0
0
1.1
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0.7
0.5
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0
0.1
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0.4
0.4
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77.2
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0.6
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Note: A zero indicates emissions of less than 50,000 metric tons per year.
         Figure 6-3.  Nationwide emission estimates,  1977  (10
                       metric tons/year).
                                    6-5

-------
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         CARBON MONOXIDE
               53%
                                                 SUSPENDED
                                                 PARTICLES
                                                    6%
           Matin* Air Qutftty. Monitoring, and Emtacfon Trancte ftopon. 1977,
           US EPA, December 1078.
Figure  6-6.   Air emissions of pollutants in  the United  States.
                               6-8

-------
                   DECREASING
                     13.2%
                                     GASOLINE
                                     MARKETING
                                       11.5%
            SURFACE COATINGS
                40.1%'    /
                         /
     DRY CLEANING
          3.6%
MANUFACTURING
     2.2%
 FUEL COMB.
    3.5%

    TRADE
    PAINTS
     5.0%
        PRINTING
          5.1%
                                                   BULK  PETROLEUM
                                                   STORAGE  22.1%
                                                 AIRCRAFT,  RAILROADS,
                                                 VESSELS,    INCINERA-
                                                 TION 3.9%
                        INDUSTRIAL
                         "PAINTS"
                          11.4%
                                            FABRIC/RUBBER
                                                 6.2%
               (Note:  Highway vehicles are excluded)

Source:  Reference 4.

Figure 6-7.   An example  of  pie  chart  displaying  the  distribution
             of VOC emissions in  a  survey  area.
                                6-9

-------
        Monthly
         3
        m
        •o
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                JFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJ
                         1977                  1978                  1979
       Yearly
        c
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90
80

70

60
50
40
30
20
10
                                            Tiansportation
                            s--	w- •—rTT
               1973
             1974
                                     1975
1976
1977
                                                        1978
                                                                               1979
*Btu consumption for all sectors is cumulated to create total
        Figure  6-8.   Energy consumption by  economic sector.
                                          6-10

-------
   1,000,000 	
o
o
9.   100,000

E

-------
of emission variations will aid regulatory personnel in such activities as
planning the operation of air quality monitoring stations; scheduling
enforcement activities; and establishing air quality management priorities,
based on historical or, as in Figure 6-9, projected emission estimates.

     Bar charts, Figures 6-10 and 6-11, are another common method of
presenting emission data.  Like the other graphical methods, they provide
visible comparisons of emission magnitudes.  When used to present historical
trends of multiple sources, as in Figures 6-10, the bar chart clearly shows
the trend in overall emissions as well the trend in emissions from individual
components, particularly those of major contributors.  Figure 6-11 shows how
the same set of data can be presented in two separate ways using bar charts.
The amount and type of fuel used by the major consumer categories are
presented and certain dependencies are easily distinguished, such as the use
of petroleum in the transportation sector.

     Another graphical technique that is useful for the presentation of air
quality data is the emission density map, as shown in Figures 6-12, 6-13 and
6-14.  These emission density presentations identify the spatial distribution
of emissions.  They clearly indicate specific areas of concern, and have been
used by agencies to present justification for adaptation of area specific
emission regulations.

     The tabular and graphical display techniques shown in this section do not
represent the only methods of presenting emission inventory data.  The
specific purpose of the summary, the source indicators that are to be
summarized, the data reporting capabilities of the data system, and the
environmental awareness of the audience must be considered before specific
techniques are selected and used by the agency.

6.2  SUMMARY OF INVENTORY DATA SYSTEMS

     Emission inventory systems of varying complexity are presently installed
at all state and most local air pollution control agencies.  The complexity
and sophistication of the systems used by state or local agencies reflect many
factors, including the number and type of emission sources within the state
and the technical and financial resources available to the agency.  While EPA
has specific emission inventory reporting requirements, the manner in which
data are stored and handled is left to the individual state agencies.  Several
methods of handling emission inventory data have evolved, based on special
in-house data requirements.

     Currently (circa 1980), about 20 state agencies use the Comprehensive
Data Handling System (CDHS) to manage their emission inventory data.  The
software for CDHS is provided by EPA to the state/local control agencies for
installation on their own computers.  The system is designed to assist the
agency in meeting EPA reporting requirements and all software and updates to
the system are provided by EPA's National Air Data Branch (NADB).  CDHS
consists of the following subsystems:
                                       6-12

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                                       6-13

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               Coal
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 Gas
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                                       Petroleum
Hydro
Electric
                                       Nuclear
     Other
    Plus Net
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                                                       Coal, Net Coke Imports, and Other
                                                       Petroleum
                                                       Natural Gas (Dry)
                                                       Hydroelectric, Nuclear
                                                       Electricity Distributed and Losses
                                                                            2.228
                  Residential
                     and
                 Commercial
          Industrial
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Utilities
 Figure 6-11.    Energy  consumption  by  fuel use  and consumer  category.
                                           6-14

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     Figure  6-14.   Location  and emission  rate of alJ  plants emitting  SO-
                                        6-17

-------
     AQDHS (Air Quality Data Handling Subsystem)—An air quality data base.
          Prepares a data set for submission to EPA to automatically satisfy
          agency reporting requirements.

     EIS/AS and EIS/PS (Emission Inventory System/Area Sources and Emission
          Inventory System/Point Sources)-'-»^—A data base describing sources
          of pollution, levels of pollution, and descriptive data related to
          permits or registrations.

          Supports the agency functions of inspection, complaint
          investigation,  legal compliance, and source surveillance.

          Prepares a data set for submission to EPA to automatically satisfy
          agency reporting requirements.

     EMS (Enforcement Management Subsystem)—A data base for use by state
          and local agencies to control enforcement activities.

          Prepares reports, including standardized letters which can be mailed
          directly to sources.

A typical source printout for the EIS/PS subsystem was presented in Figure
6-1.  EIS/PS information requirements are based largely on the NEDS system,
and Its format contains all source and emission details currently needed to
meet various planning and enforcement applications.  EIS data can be converted
to the required NEDS format automatically, through use of a conversion
program, thereby minimizing manpower requirements.  Once installed, EIS/PS is
extremely easy to use.  EPA will provide assistance when a user encounters
problems and also provides training sessions for users of the system
throughout the country on a periodic basis.

     Approximately 15 of the remaining state agencies utilize some form of
automated emission Inventory.  These systems include the AIR-100 system used
in New York State, the IBM Mr Pollution Control Starter System currently used
in Connecticut and Nebraska, and the Illinois Total Air System.  The general
source and emission data contained In these systems are essentially the same
as that for EIS/PS as can be seen by an examination of the AIR-100 printout
presented in Figure 6-2.  Although there are potential benefits in developing
and using an emission inventory data system that is specifically designed for
the needs of an agency, it is generally recommended that EIS be adopted by the
states now operating without automated emission inventory systems because of
its ease of use, widespread acceptance, excellent retrieval capabilities, and
available support from EPA.
                                     6-18

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References for Chapter 6.0

1.   The Emissions Inventory System/Point Source User's Guide,
     EOA-450/4-80-010, U.S. Environmental Protection Agency, Research Triangle
     Park, NC, May 1980.

2.   1974 National Emissions Data System (NEDS) Fuel Use Report,
     EPA-450/2-77-031, U.S. Environmental Protection Agency, Research Triangle
     Park, NC, April 1978.

3.   1977 National Emissions Report, EPA-450/4-80-005, U.S. Environmental
     Protection Agency, Research Triangle Park, NC, March 1980.

4.   Procedures for the Preparation of Emission Inventories for Volatile
     Organic Compounds, Volume I, Second Edition,  EPA-450/2-77-028, U.S.
     Environmental Protection Agency, Research Triangle Park,  NC, March 1980.

5.   Systems Study of Air Pollution From Municipal Incineration, APTD 1283,
     U.S. Environmental Protection Agency,  Research Triangle Park, NC, March
     1970.

6.   The Emission Inventory System/Area Source User's Guide, EPA-450/5-80-009,
     U.S. Environmental Protection Agency,  Research Triangle Park, NC, May
     1980.
                                    6-19

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                     7.0  MANPOWER/RESOURCE ALLOCATION MODEL
     The Time Requirement Model (TREM) for conducting an emission inventory,
presented in this chapter, has been developed  to assist the  planners  of  the
inventory in estimating the manpower requirements needed to  achieve the
objectives of the inventory.  Time requirements, based largely on past
experience, are estimated for discrete activities that, in total, comprise the
full range of activities involved in preparing an emission inventory.

     The time requirement Cor each defined activity is comprised of both a
linear and fixed component.  The linear component is a function of the number
of sources, and assumes that the time required to perform the operations
comprising an activity  (e.g., code a form as part of a defined data
compilation activity)remains the same  throughout  the  inventory  effort.   The
fixed component is independent of the number of sources and  represents the
time required; for example, to develop a coding form and/or  to write  programs
to edit and verify the coded data.  The fixed  time requirement will vary from
activity to activity, depending upon the definition of an activity and its
associated fixed components.  In the example above, the writing of edit and
verification programs cou] d logically be classified as a separate activity-
distinct from coding; e.g., as part of a quality assurance activity.
Regardless of the classification of work elements within activities,  the
general expression for the total time required to perform an activity is given
by the general expression

                               TT  =   Tf  + nTa                              (7-1)

where

     TT = Total time required to perform an activity

     Tf = Fixed time associated with an activity

      n = The number of operations required to complete an activity
          (usually the number of sources or counties within  the inventory area)

     Ta = Time required to complete an operation within an activity

     As an example of the use of Equation 7~1,  consider the  time involved in
preparation of a point source list.   The establishment of an initial source
list requires that a large number of reference sources (see  Chapter 5) must be
reviewed to prepare a complete  listing of all point sources.   A senior
engineer will be needed to organize  and direct the literature search and to
contact facilities to determine if they should be included in the listing of
potential point sources.  The senior engineer should  understand  industrial
processes within the jurisdiction which are likely to be point sources of
emissions.   He will be assisted by  a junior engineer  who will review the
literature and identify the facilities and a technician to code  and enter the
data into a mailing list file.
                                      7-1

-------
     The fixed time associated with such an activity (Tp) is estimated to be
24 hours of senior engineer time and 80 hours of junior engineer time for a
total of 104 hours; the time required to code and install the listing in the
file (Ta) is estimated to be 0.04 hour per source.  If there are 1000 point
sources the time required (nTa) is 40 hours.   Thus TT the total time
required initially to develop a point source listing is 144 hours.

                           TT  = 104+  1000  (0.04)  - 144

The maintenance of the initial listing will require far less effort.
Estimates of the fixed time associated with an activity is 8 hours  of senior
engineer and 20 hours of junior engineer time.  The time required to code and
install new sources (or delete sources) is the same as for the initial effort
(0.04 hours per source), but the number of sources will generally be far less
than the initial number.  If 100 sources are added to the point source listing
the total maintenance effort is

                        TT = 28 + 100 (0.04) = 32 hours.

The model expression, Equation 7-1, is presented graphically in Figure 7-1.
The time requirement for an activity will depend not only upon the  number of
sources and counties to be inventoried, but will also depend upon the
following:

     Level of detail required,

     Skill of personnel,

     Availability of data,

     Status of existing inventory,

     Status of existing data handling system,

     Status of existing quality assurance program.
         IO
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                                              MAN-HOURS
                   ITEMS (SOURCES) TO  BE  PROCESSED

         Figure 7-1.   Time requirement  model—graphical representation.

                                      7-2

-------
The agency will be required to make some judgments concerning the above
factors and adjust the time requirements of the TREM as presented in this
chapter.  When an agency has conducted inventories regularly, its past
experience can be used to estimate time requirements.  If an agency desires
additional information concerning time and manpower requirements, information
can be found in the published literature.^>^>3  in addition, a computer
model is available from EPA which estimates technical and administrative costs
associated with preparing emission inventories.  To obtain additional
information, contact an EPA Regional Office or the Control Programs Operations
Branch, Control Process and Development Division, MD-15, U.S. Environmental
Protection Agency, Research Triangle Park, NC, 27711.

     The activities involved in developing the total inventory of point, area
and mobile sources are listed in Table 7-1, along with the results of the TREM
analysis for each activity.  Each of these activities, referred to in the
model as a "task,", is discussed separately, specific assumptions defined, and
time requirements estimated for both an initial inventory (TTj) and an
inventory maintenance effort (TTj,j).  Each task (activity) presentation is
formatted to provide the information listed below.

      1.  Task:  Name of the task.

      2.  Task overview:  A general overview of the activities included in the
          task and any special instructions for interpreting and using the
          included information.

      3.  Occupational category:  The educational background of agency
          personnel;  e.g.,  senior or junior engineer or computer software
          specialist.

      A.  Knowledge and skill requirements:  Additional knowledge and
          experience of personnel required to effectively perform the task.

      5.  Time requirements:  TREM determined manpower requirements for both
          the initial effort and the maintenance effort.
                                      7-3

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                TABLE  7-1.   TIME REQUIREMENT MODEL  (TREM)  SUMMARY
                                                   Initial
                                                  effort T
                                                   (hours)
Maintenance
 effort TTM
  (hours)
Point Source Inventory

Establishment of a source list
Development of a questionnaire
Printing mailing list and labels
Mail questionnaires
Logging and review of returns
Assignment of codes
Data coding
Calculation of emissions
Quality assurance
Data presentation

Area Source Inventory

Data collection
Program compilation
  Existing software
  New software
Data coding
Software development
  Existing software
  New software
Calculation of emissions
  Manual approach
  Computerized approach
Quality assurance
Data presentation

Mobile Source Inventory

Establishment of liasons with other agencies
Data collection
Data coding
Software development
  Existing software
  New software
Calculation of emissions
  Manual approach
  Computerized approach
Quality assurance
Data presentation
104 + 0.04n
56
8 + 0.0005n
0.02n
8 + 0.2n
40 + O.ln
40 + 0.3n
40 + 0.5n
16 + 0.02n
40
80 + 0.25n
0.25 + O.OOln
40 + O.OOln
40 + 0.75n
80 + 0.2n
280 + 0.2n
40 + 8n
20 + 0.2n
20 + In
80
120
80 + 0.25n
40 + 0.75n
80 + 0.2n
280 + 0.2n
40 + 8n
40 + O.ln
20 + In
80
28 + 0.04n
16
1 + O.OOOSn
0.02n
0.2n
O.ln
0.2n
0.3n
16 + 0.02n
40
0.25n
0.25 + O.OOln
0.25 + O.OOln
0.75n
0.2n
8 + 0.2n
20 + 6n
20 + 0.2n
20 + In
80
120
0.25n
0.75n
0.2n
8 + 0.2n
20 + 6n
8 + O.ln
20 + In
80
                                      7-4

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   TIME REQUIREMENT MODEL
BY ACTIVITY FOR POINT SOURCES
             7-5

-------
TIME REQUIREMENT MODEL BY ACTIVITY:  Point Sources

TASK:                   Establishment of a source list
TASK OVERVIEW:
OCCUPATIONAL CATEGORY:
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:(1)
The establishment of an intial source list is a
time-consuming task.  A large number of references
(see Chapter 5) must be consulted and cross-checked to
ensure that all sources are included.  Although the
number of sources in the listing can be limited by
judicious selection of a cutoff size for each source
category, based on an indicator such as employment, a
large initial effort is worthwhile.  An expanded
listing will prove helpful in reducing the effort
required by the agency if, for example, the point
source emission level is lowered in future programs.
Accordingly, it is recommended that, in preparing the
point source list, a conservative estimate of
emissions vs. employment (or other indicator) be
adopted for preparation of the initial mailing list.
Plant names, addresses, telephone numbers and contacts
must be assembled, and, if possible, coded and
keypunched for further use.

A senior engineer to organize and direct the
literature search and contact facilities, when
necessary; a junior engineer to review the literature
and identify the facilities to be listed; a technician
to either code or photostat acquired data; and a
keypunch operator.
In addition to a knowledge of process emissions, a
knowledge of demographic data is important, along with
some statistical knowledge, in order to assess factors
that would identify the emission potential of a
company.
Initial effort
     TTj
                                        nT
          T  =
                                       24 hr of senior engineer
                                       + 80 hr of junior engineer, 104 hr

                                       1 hr/50 sources to photostat or code
                                       + 1 hr/50 sources to keypunch; 2 hr/
                                       50 sources or 0.04 hr/source
                                   n = number of sources

                                 = 104 + 0.04n hr
                                      7-6

-------
(2)   Maintenance effort

     TTM = Tf  + nTa

          Tf = 8 hr  of  senior  engineer
               + 20  hr  of  junior  engineer, 28 hr

          Ta = 2 hr/100 sources,  to photostat or  code
               necessary changes  +  2 hr/100 sources
               to keypunch, 4  hr/100 sources; 0.02
               hr/source

           n = number of sources

     TTM = 28  + 0.04n hr
             7-7

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TIME REQUIREMENT MODEL BY ACTIVITY:   Point Sources

TASK:                   Development  of a questionnaireCs)
TASK OVERVIEW:
OCCUPATIONAL CATEGORY:
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
This activity involves a one-time effort to create a
simple questionnaireCs) to gather all necessary source
data.  Alternatively, standard questionnaires,  such as
those described in Volume II,^ could be used.  For
maintenance purposes, this activity requires the
development of a miniquestionnaire that includes such
data items as a fuel update and changes in process or
control equipment.

A senior engineer to develop the questions, a
principal engineer to review them, and a computer
specialist to assist in the formatting of the
questionnaire for subsequent computerization of the
data.
A knowledge of processes, air pollution technologies,
and source evaluation ability are essential.
(1)
     Initial effort

     TTj = Tf + nTa
(2)
                                  In this activity n = 1 (one-time activity),
                                  so this equation reduces to
                                        = T
                                  Based on the past experience of several
                                  agencies,  this time requirement involves:

                                    5 days of senior engineer time;
                                    1 day of principal engineer time;  and
                                    1 day of computer specialist time.

                             TTj = 7 days, or 56 hr

                             Maintenance effort

                             The time requirement for maintenance effort could
                             involve:

                               1 day of senior engineer time;
                               1/2 day of principal engineer/scientist  time;
                                 and
                               1/2 day of computer specialist time.

                             TTM = 2 days, or 16 hr
                                      7-8

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TIME REQUIREMENT MODEL BY ACTIVITY:  Point Sources

TASK:                   Printing mailing list and labels

TASK OVERVIEW:          This activity involves a one-time software development
                        effort to create a mailing list and labels.  For
                        maintenance purpose, it only requires the execution
                        and running of the developed program.  The mailing
                        labels are preferably keyed by an ID and SIC number to
                        facilitate logging of returns.

OCCUPATIONAL CATEGORY:  A junior programmer

KNOWLEDGE AND SKILL
REQUIREMENTS:           A knowledge of either FORTRAN or COBOL computer
                        language is essential to carry out this activity.  A
                        programmer should also be able to use available
                        computer software packages such as EASYTRIEVE,  SPSS,
                        etc,

TIME REQUIREMENT:       (1)  Initial effort

                             TTT = Tf + nTa

                                  Tf = 8 hr if FORTRAN is used,
                                       6 hr if COBOL is used

                                  Ta = 0.25 hr/500 labels, or
                                       0.0005 hr/label

                                   n = number of labels (sources)

                             TTj = 8 + 0.0005n

                        (2)  Maintenance effort

                             TTM - Tf + nTa

                                  Tf = 1 hr, considerably less than initial
                                  effort since a software package has been
                                  developed.  A programmer must assemble the
                                  previously developed program, use JCL  (Job
                                  Control Language)  and create a source list
                                  and mailing labels

                                  Ta = 0.0005 hr/label;  remains unchanged

                                   n = number of labels  (sources)

                             TTM = 1 + 0.0005n hr
                                     7-9

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TIME REQUIREMENT MODEL BY ACTIVITY:  Point Source
TASK:

TASK OVERVIEW:
                        Mail questionnaire

                        This is a very simple task.   It involves attaching the
                        preprinted label to a questionnaire, placing the
                        questionnaire in an envelope and attaching a second
                        label,  identical to the first, to the mailing
                        envelope, which is then mailed.

OCCUPATIONAL CATEGORY:  A technician or member of the support services staff
KNOWLEDGE AND SKILL
REQUIREMENTS:

TIME REQUIREMENT:
                        None
                        The total time required for the initial effort and for
                        the maintenance effort is the same.
                            = TTM = Tf
                                         nT
                             There is no Tf time associated with this task;
                             all effort is related to the number of
                             questionnaires being mailed.

                             TTZ = TTM = nTa

                              Ta = 1 rain per source, or 0.02 hr/ source

                               n = number of sources

                             TTr = TTM = 0.02n hr
                                     7-10

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TIME REQUIREMENT MODEL BY ACTIVITY:  Point Sources
TASK:

TASK OVERVIEW:
                        Logging and review of returns

                        Questionnaires will be logged in and reviewed once
                        they are received.  The purpose of the review is to
                        ensure that all questions have been properly
                        answered.  It does not involve an in-depth technical
                        Teview which will be done by personnel responsible
                        for data coding and emissions calculations.

OCCUPATIONAL CATEGORY:  A junior engineer reviews incoming questionnaires and
                        a technician logs them in.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
                        Some process knowledge, plus a general knowledge of
                        the geographic area, including familiarity with the
                        local industrial base.

                        (1)  Initial effort

                             TTj = Tf + nTa

                                  Tf = fixed time required to set up
                                       techniques for logging and review
                                       system, 8 hr

                                  TN = 2 min for logging/source,  and
                                       10 min for review/source;
                                       12 min, or
                                       0.2 hr/source

                                   n = number of sources

                             TTX = 8 + 0.2n hr

                        (2)  Maintenance effort

                             TTM = Tf + nTa

                                  Tf = 0,  techniques have already been
                                       determined and documented.

                                  Ta = 0.02 hr/source,  same as initial case

                                   n = number of sources

                             TTM = 0.2n hr
                                     7-11

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TIME REQUIREMENT MODEL BY ACTIVITY:  Point Sources
TASK:

TASK OVERVIEW:
OCCUPATIONAL CATEGORY:
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Assignment of codes

This activity involves the study of a source and its
related processes to determine the most applicable
source classification codes (SCC).  A senior engineer
must thouroughly familiarize himself with the SCC
coding system in order to assign the appropriate
code.  At the same time, a junior engineer or
programmer assigns the necessary systems codes such as
plant identification, city, county, state codes, etc.

A senior engineer to assign SCC; a junior engineer or
programmer to assign system identification codes.
A knowledge of industrial processes is helpful for
assigning SCC codes.  A general knowledge of data
recording techniques is essential for assigning
geographic and system indicator codes.

(1)  Initial effort

     TTI = Tf + nTa

          Tf = 40 hr, for familiarization with
               SCC designations.

          Ta = 5 min to assign SCC codes per
               source + 1 min to assign state, county,
               city codes per source
             = 6 min per source, or 0.1 hr per source

           n = number of sources

     TTj = 40 + O.ln hr

(2)  Maintenance effort

     TTM = Tf + nTa

          Tf = 0, as the familiarization process
               is assumed to be complete
                                  Ta = identical to initial effort
                                     = 0.1 hr/source
                                   n = number of sources

                             TTM = O.ln hr
                                      7-12

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TIME REQUIREMENT MODEL BY ACTIVITY:  Point Sources
TASK:

TASK OVERVIEW:
                        Data coding

                        All source data must be coded and entered into a
                        computerized data handling system.  Regardless of the
                        emission inventory system used (NEDS, EIS, individual
                        state system,  etc.)* coding and keypunching of data
                        items is an essential processing step.

OCCUPATIONAL CATEGORY:  A junior engineer/scientist,  a keypunch operator.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
                        A Senior Engineer who knows the industries and
                        processes within the region will be required to ensure
                        that the all of the data entered into the file is
                        complete and technically correct.  He will assist the
                        two junior engineers in dealing with uncertainties and
                        will recontact facilities as required.  This operation
                        should be carried out in adherence to documented
                        procedures.   Familiarity with the computer load sheet
                        formats (assumed available) and data codes employed by
                        agency for control devices, test procedures, etc. will
                        be necessary.

                        (1)  Initial effort

                             TTI = Tf  + nTa

                                  Tf = time required to understand coding
                                  forms and procedures,  40 hr

                                  Ta = 15 min to code each source
                                       + 5 min to keypunch each source;
                                     20 min per source or 0.3 hr/source

                                  n = number of sources

                             TTX = 40  + 0.3n hr

                        (2)   Maintenance effort

                             TTM = Tf  + nTa

                                  Tf = 0,  this assumed trained personnel are
                                       available
                                     7-13

-------
          extremely variable since the number of
          keypunch cards to be modified may vary
          from 1 to 6, depending upon the data to
          be modified.  An average maintenance
          effort is 10 to 15 min/source, or 0.2
          hr/source
      n = number of sources

TTM = 0.2n hr
         7-14

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TIME REQUIREMENT MODEL BY ACTIVITY:  Point Sources

TASK:                   Calculation of emissions
TASK OVERVIEW:
This activity involves estimating emission rates from
various sources and source categories using either
AP-42 or other emission factors developed for the
industry.  It is an engineering activity, requiring an
initial high expenditure of manpower.  With time,
however, the activity becomes increasingly more
routine.
OCCUPATIONAL CATEGORY:  A senior engineer,  a junior engineer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
A knowledge of processes and controls, material
balance and dimension analysis are important.
Familiarity with conversion factors is also important.

(1)  Initial effort

     TTj = Tf + nTa

          Tf = time required to develop an
               understanding of AP-42, or similar
               reference materials, 40 hr

          Ta = 0.5 hr/source to calculate source
               emission rates

           n = number of sources

     TTj = 40 + 0.5n hr

(2)  Maintenance effort

     TTM = Tf + nTa

          Tf = 0,  as the familiarization process is
               assumed to be complete

          Ta =0.3 hr/source; once the calculation
               techniques are learned, the time
               requirement is approximately 60 percent
               of  the initial effort.

           n = number of sources

          TTM = 0.3n hr
                                      7-15

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TIME REQUIREMENT MODEL BY ACTIVITY:  Point Sources
TASK:

TASK OVERVIEW:
Quality assurance*

The objective of this task is to ensure that all data
are complete and correct.  There are visual checks and
edit program check procedures.  This task involves
running previously developed QA programs.
OCCUPATIONAL CATEGORY:  A senior programmer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
A knowledge of the use of program packages, and also
of FORTRAN or some other computer language.

Initial and maintenance efforts are always the same.

TTX = TTM = Tf + nTa

     T£ = time required to set up and execute
     programs, 16 hr

     Ta = 1 rain/source, or 0.02 hr/source

      n = number of sources

TTX = TTM = 16 + 0.02n hr
*This action only performs machine edits and validity checks on coded
 information and is not the quality assurance that must be performed manually
 by competent engineers responsible for data review and coding.
                                      7-16

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TIME REQUIREMENT MODEL BY ACTIVITY:  Point Sources

TASK:                   Data presentation

TASK OVERVIEW:          Once all data on point sources have been assembled,
                        reports are generated which present these data in
                        predetermined formats.

OCCUPATIONAL CATEGORY:  Senior engineer.

KNOWLEDGE AND SKILL
REQUIREMENTS:           Good communication skills and knowledge of the data
                        requirements of an agency are important.

TIME REQUIREMENT:       TTj; = TTM = Tf + nTfl

                             The generation of a specific report will
                             always require the same amount of time.   This
                             time will vary, depending on the number of
                             sources in the inventory.  It is estimated that,
                             on the average, this task will require 40 hr for
                             all reporting.

                             TTZ = TTM = 8 hr
                                     7-17

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   TIME REQUIREMENT MODEL
BY ACTIVITY FOR AREA SOURCES
           7-18

-------
TIME REQUIREMENT MODEL BY ACTIVITY:  Area Sources
TASK:

TASK OVERVIEW:
Data collection

Assuming that data needs have been identified, the
data collection activity begins.  Data logging
activities for received data is included in this
activity.
OCCUPATIONAL CATEGORY:  A senior engineer and a technician.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Communication skills and a knowledge of demographic
data.

(1)  Initial effort

     TTI = Tf + nTa

          If = time required to identify data source
               contacts and verify information or
               obtain missing information by
               telephone, 80 hr

          TN = time required to compile and log in
               data is 15 minutes or 0.25 hr/county

           n = number of counties

         TTj = 80+ 0.25n hr

(2)  Management effort

     TTM = TF TnTN

          Tp = 0,  techniques have been determined
               and personnel are familiar with them

          TN = 0.25 hr/source,  same as initial case

         TTM = 0.25n hr
                                     7-19

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TIME REQUIREMENT MODEL BY ACTIVITY:  Area Sources

TASK:                   Program compilation

TASK OVERVIEW:
                        The development of an area source inventory requires
                        compilation of previously developed programs.
OCCUPATIONAL CATEGORY:  A senior programmer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
                        A knowledge of either FORTRAN or any assembly language
                        is essential.

                        (1)  TTinitial - Tf + nTa

                                  Tf = program setup time, 0.25 hr

                                  Ta = time to run program, 0.001 hr/county

                                       number of counties
                                   a

                                   n
                                   0.25 + O.OOln hr
                             This is the time requirement if the language and
                             the system are the same as the original program.
                             If the language or the system is different, then
                             the following time estimate to modify and test
                             the software on the agency's system should be
                             used.

                             TTinitial - Tf + nTa

                                  Tf = software setup and debugging time,
                                       40 hr

                                  Ta = time to execute program, 0.001
                                       hr/county

                                   n = number of counties
                        (3)  TTM = Tf + nTa

                             The maintenance effort for either case (1) or (2)
                             above is the same, inasmuch as a system and a
                             language will have been chosen.
                                      7-20

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     Tf = setup time for the program, 0.25 hr

     Ta = time to execute the program, 0.001
          hr/county

      n = number of counties

TTM = 0.25 + O.OOln hr
         7-21

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TIME REQUIREMENT MODEL BY ACTIVITY:  Area Sources
TASK:

TASK OVERVIEW:
                        Data coding

                        If a computerized system is used, it is necessary to
                        code data as required by the system, using a coding
                        form designed for the system.  The coded data must be
                        keypunched.

OCCUPATIONAL CATEGORY:  Junior engineer, a keypunch operator.
KNOWLEDGE AND SKILL
REQUIREMENTS:

TIME REQUIREMENT:
                        A knowledge of coding and computer systems is helpful.

                        (1)  Initial effort

                             TTI = Tf + nTa

                                  Tf = 40 hr, a junior engineer is
                                       required

                                  Ta = 30 min to code each county
                                       + 15 min to keypunch each county; 45
                                       min/county or 0.75 hr/county

                                   n = number of counties

                             TTX = 40 + 0.75n hr

                        (2)  Maintenance effort

                             TTM » T£ + nTa

                                  Tf = 0, since the engineer is already
                                       aware of the coding needs.

                                  Ta = the same as initial effort, 0.75
                                       hr/county
                             TTM
                                   n = number of counties

                                   0.75n hr
                                      7-22

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TIME REQUIREMENT MODEL BY ACTIVITY:  Area Sources

TASK:
TASK OVERVIEW:
                        Software development for apportioning data on a county
                        level (or grid level)

                        This activity is necessary if an area has many
                        counties, and area source data must be apportioned to
                        each.  The activity can be broken down into (1)
                        developing software and (2) use of existing programs.

OCCUPATIONAL CATEGORY:  A junior programmer, a senior programmer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
                        A knowledge of programming and SPSS, or similar
                        packages is essential.

                        (1)  Developing software

                             (a)  Initial effort

                                  TTj = If + nTa

                                       Tf = 280 hr,  time required to
                                       understand, set up, develop,  and
                                       compile  a program

                                       Ta = 0.2 hr/county

                                        n = number of counties

                                  TTj = 280 + 0.2n hr

                             (b)  Maintenance effort

                                  TTM - Tf + nTa

                                       Tf = 8 hr,  there is no need to develop
                                            a program since this activity is
                                            only involved with compiling
                                            programs and executing them.

                                       Ta = identical to that of the initial
                                            effort,  0.2 hr/county

                                        n = number of counties

                                  TTM = 8 + 0.2n hr
                                     7-23

-------
(2)   Use of previously developed programs

     (a)  Initial effort

          TTj = Tf + nTa

               Tf = 80 hr,  to understand, install
               and compile  existing programs

               Ta = remains the same,  0.2 hr/county

                n = number  of counties

          TTj; = 80 + 0.2n hr

     (b)  Maintenance effort

          TTM = Tf + nTa

               Tf = 0

               Ta = remains the same,  0.2 hr/county

                n = number  of counties

          TTM = 0.2n hr
             7-24

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TIME REQUIREMENT MODEL BY ACTIVITY:  Area Sources
TASK:

TASK OVERVIEW:
OCCUPATIONAL CATEGORY
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Calculation of emissions

Two ways to calculate emissions are (1) manually and
(2) computerized.  If an agency uses a computer for
coding and apportioning data, it should use the
computer to calculate emissions.  Emission factors can
be built into the program.

A junior engineer, senior engineer—Manual System
A junior programmer, senior programmer—Computerized
  System
Use of emission factors and understanding of basic
programming, using standard packages.

(1)  Manual approach

     (a)  Initial effort

          TTI = Tf + nTa

               Tf = 40 hr to understand the use of
                    AP-42 emission factors

               Ta = 8 hr for calculating emissions
                    for all area source activities in
                    each county

                n = number of counties

          TTj = 40 + 8n hr

     (b)  Maintenance effort

          TTM = Tf + nTa

               Tf = 20 hr,  as familiarity with the
                    use of emission factors will
                    decrease the time

               Ta = 6 hr/county, since this task
                    becomes routine

                n = number of counties

          TTM = 20 + 6n hr
                                     7-25

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(2)   Computerized approach

         = TTM =  Tf  + nTa
          Initial  and  maintenance  efforts  are  the same
          since  computer programs  have been previously
          developed.   Execution,  startup,  compilation
          and running  time will  be identical.

          Tf  = 20  hr

          Ta  = 0.2 hr/county

           n  = number  of counties

     TTL = TTM = 20 +  0.2n hr
             7-26

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TIME REQUIREMENT MODEL BY ACTIVITY:  Area Sources

TASK:                   Quality assurance

TASK OVERVIEW:
The objective of this task is to make sure all data
are correct.  Spot checks of data, and edit check
programs can be used.
OCCUPATIONAL CATEGORY:  A senior programmer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
A knowledge of program packages and how to use them is
necessary.

TTj = TTM = Tf + nTa

     Initial and maintenance efforts will be the same.

     Tj = 20 hr to understand, setup and execute
          program

     Ta = 1 hr/county

      n = number of counties

     TTX = TTM = 20 + In hr
                                     7-27

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TIME REQUIREMENT MODEL BY ACTIVITY:  Area Sources
TASK:

TASK OVERVIEW:
Data presentation

A report, which is a one-time effort, is generated
after all data are put together.  This report
documents an area source emission inventory.
OCCUPATIONAL CATEGORY:  Senior engineer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Good communication skills and an awareness of agency
data needs are important.
= TT
                                M
                 nT
                             Initial and maintenance efforts are the same.
                             Both are one-time efforts, which are essentially
                             unrelated to the number of counties in the area.

                             Tf = 80 hr.  This is an estimate based on
                                  average report lengths.
                                 = TT
                                     M
                 80 hr
                                      7-28

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    TIME REQUIREMENT MODEL
BY ACTIVITY FOR MOBILE SOURCES
            7-29

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TIME REQUIREMENT MODEL BY ACTIVITY:  Mobile Sources
TASK:

TASK OVERVIEW:
Establishment of liaisons with other agencies

The development of a mobile source inventory involves
some coordination with other agencies.  Management in
the emission inventory agency should contact other
federal, state and local agencies and request their
support.
OCCUPATIONAL CATEGORY:  A principal engineer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Good communication skills and the ability to work with
other agency personnel.
= TT
                                M
                 nT
                             Initial and maintenance efforts always remain the
                             same.  This effort continues for the entire
                             process of developing and/or maintaining the
                             emission inventory.

                             Tf = 120 hr

                             Ta = 0, as this task is not related to the
                                  number of counties included in the inventory

                        TTX = TTM = 120 hr
                                      7-30

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TIME REQUIREMENT MODEL BY ACTIVITY:  Mobile Sources

TASK:                   Data collection

TASK OVERVIEW:
This task involves contacting people and agencies to
obtain the required data.  A log of data that are
requested and received should be maintained.
Verification of received data is also required.
OCCUPATIONAL CATEGORY:  A junior engineer and a technician.
KNOWLEDGE AND SKILL
REQUIREMENTS:

TIME REQUIREMENT:
Communication skills and a knowledge of traffic data.

(1)  Initial effort

     TTX = Tf + riTa

          Tf = 80 hr, the time to identify contacts

          Ta = 0.25 hr/county, the time to request,
          log and verify data

            n = number of counties

          TTj <= 80 -v 0.25n hr

(2)  Maintenance effort

     TTM = Tf + nTa

          If is zero, while Tfl remains the same as
          that for the initial effort.

     TTM = 0.25n hr
                                     7-31

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TIME REQUIREMENT MODEL BY ACTIVITY:   Mobile Sources
TASK:

TASK OVERVIEW:
Data coding

Coding and keypunching data for the computer, or a
program (MOBIL1 or APRAC, etc.), to calculate
emissions for on-highway and off-highway sources;
coded data are keypunched.
OCCUPATIONAL CATEGORY:  A junior programmer, a keypunch operator.
KNOWLEDGE AND SKILL
REQUIREMENTS:
Coding skills and an understanding of coding forms.

(1)  Initial effort

     TTI ~ Tf + nTa

           Tf = 40 hr, junior programmer to review
               and develop familiarity with
               techniques

           Ta = 30 min/county to code and 15 min/
                county to keypunch; 45 min/county
                or 0.75 hr/county

            n = number of counties

          TTj = 40 + 0.75 n hr

(2)  Maintenance Effort

     TTM = Tf + nTa

          Tf is not necessary, since the junior
          programmer has already established the
          mechanism for coding data.  Ta remains the
          same as in the case of the initial effort.

          Ta = 0.75 hr/county

           n = number of counties

     TTM = 0.75n hr
                                     7-32

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TIME REQUIREMENT MODEL BY ACTIVITY:  Mobile Sources

TASK:
TASK OVERVIEW:
Software development for apportioning data on a county
level (or grid level)

This activity can be broken down into two tasks:  (l)
development of necesary software and (2) use of
previously developed programs.
OCCUPATIONAL CATEGORY:  A senior programmer,  a junior transportation
                        programmer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
A knowledge of transportation programming and skill in
the use of SPSS or similar packages is helpful.

(1)  Developing software

     (a)  Initial effort

          TTj = Tf + nTa

               Tf = 280 hr, time for a programmer to
                    understand the data needs of an
                    agency and then develop a program

               Ta = time required for each county
                    0.2 hr/county

                n = number of counties

          TTj = 280 + 0.2n hr

     (b)  Maintenance effort

          TTM - Tf + nTa

               Tf = 8 hr,  the time to compile a
                    program, use a data set and
                    execute the programs

               Ta = 0.2 hr/county; remains the same

                n = number of counties

          TTM = 8 + 0.2n hr
                                     7-33

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(2)   Use of previously developed  programs

     (a)  Initial effort

          TTI = Tf + nTa

               Tf = 80 hr,  the time to understand,
                    install,  and  test the  programs  on
                    the agency's  computer  system

               Ta = computer  time for each county,
                    0.2 hr/county;  remains the same

                n = number  of counties

          TTX = 80 + 0.2n hr

     (b)  Maintenance effort

          TTM - Tf + nTa

               Tf = 0, as the programs have been
                    compiled

               Ta = same  as for the initial effort,
                    0.2 hr/county

                n = number  of counties

          TTM = 0.2n hr
              7-34

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TIME REQUIREMENT MODEL BY ACTIVITY:  Mobile Sources

TASK:                   Calculation of emissions

TASK OVERVIEW:          There are two ways to calculate emissions:  (1)
                        manually and (2) using a computer with MOBIL1, APRAC,
                        or some other program.

OCCUPATIONAL CATEGORY:  A junior engineer, senior engineer—Manual
                        A junior programmer,  senior programmer—Computerized
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Understanding and use of emission factors; also basic
programming skills using standard packages.

(1)  Manual approach

     (a)  Initial effort

          TTX = Tf + nTa

               Tf = 40 hr,  to understand all the
                    emission factors and use of
                    conversion factors

               Ta = 8 hr/county,  for calculating
                    emissions for on-highway and
                    off-highway sources

                n = number of counties

          TTZ = 40 + 8n hr

     (b)  Maintenance effort

          TTM = Tf + nTa

               Tf = 20 hr,  activity has become
                    routine

               Ta = 6 hr/county,  less for the same
                    reason

                n - number of counties

          TTM = 20 + 6n hr
                                      7-35

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(2)   Computerized approach

     (a)   Initial effort

              = Tf + nTa
               Tf = 40 hr,  the time required to
                    install a program on the system
                    and get it working

               Ta = 0.1 hr/county

                n = number  of counties

          TTj = 40 + O.ln hr

     (b)   Maintenance effort

          TTM = Tf + nTa

               Tf = 8 hr, time is reduced because
                    the program is already installed.

               Ta = 0.1 hr/county; remains the same

                n = number  of counties

          TTM = 8 + O.ln hr
             7-36

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TIME REQUIREMENT MODEL BY ACTIVITY:  Mobile Sources
TASK:

TASK OVERVIEW:
Quality assurance

The objective of this task is to make sure the quality
of the data is acceptable.  Input data should be
either spot checked, or reviewed through edit check
programs.
OCCUPATIONAL CATEGORY:  A senior programmer.
KNOWLEDGE AND SKILL
REQUIREMENTS:

TIME REQUIREMENT:
Knowledge of edit program packages and their use.

Initial and maintenance efforts are the same.

TTX = TTM = Tf + nTa

     Tf = 20 hr, the time to understand and set up
          programs

     Ta = 1 hr/county; to check input data and flag
          errors

      n = number of counties

TTj = TTM = 20 + In hr
                                     7-37

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TIME REQUIREMENT MODEL BY ACTIVITY:  Mobile Sources
TASK:

TASK OVERVIEW:
Data presentation

A report which is a one-time effort is generated after
all data are combined and emissions calculated.  This
report documents the mobile source emission inventory.
OCCUPATIONAL CATEGORY:  Senior engineer.
KNOWLEDGE AND SKILL
REQUIREMENTS:
TIME REQUIREMENT:
Good writing skills and an understanding of agency
needs.
TTI " TTM =
                 nT
                             Tf = 80 hr,time required to write a summary
                                  report, which is the same for initial and
                                  maintenance efforts

                             Ta = 0, as the report is not dependent upon the
                                  number of counties surveyed

                        TTj = TTM - 80 hr
                                       7-38

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                                APPENDIX A

                                DEFINITIONS
     This section provides definitions of terms employed by air pollution
control agencies in conducting emission inventories and related regulatory
functions.   The terms presented in Appendix A provide a working basis
for consistency among local, state and Federal agencies.

     The words and terms listed in Appendix A were collected from various
publications such as the Federal Register,  EPA Documents and Manuals, State
Implementation Plans, and the Clean Air Act.   The references served to
identify terminilogy used by Federal and State Governments in regulations
governing air pollution control and prevention.
                                   A-l

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     Term
ACTIVITY LEVEL
               Definition

Rate relating the amount of fuel con-
sumed, quantity of product manufactured
in an industrial process, or some com-
parative measure.
    Reference
EPA-450/2-78-026
ADEQUATELY WETTED Sufficiently mixed or coated with water
                  or an aqueous solution to prevent dust
                  emissions.
                                           40 CFR 61.02
AFFECTED FACILITY With reference to a stationary source,
                  any apparatus to which a standard is
                  applicable.
                                           40 CFR 60.2
AIR POLLUTANT
Any air pollution agent or combination
of such agents, including any physical,
chemical, biological, radioactive (in-
cluding source material, special nuclear
material, and byproduct material) sub-
stance or matter which is emitted into
or otherwise enters the ambient air.
Clean Air Act
Sec. 302(g)
AIR POLLUTION
REQUIREMENT
Any emission limitation, schedule or
timetable for compliance, or other re-
quirement, which is prescribed under
any Federal, state, or local law or
regulation, including the Act* (except
for any requirement prescribed under
section 119 (c) or (d), Section 110(a)
(2)(F)(v), or Section 303 of the Act),
and which limits stationary source
emissions resulting from combustion of
fuels (including a prohibition on, or
specification of, the use of any fuel
or any type, grade, or pollution char-
acteristic) .
40 CFR 55.02
AIR QUALITY
CONTROL REGION
(AQCR)
Designated by the Administrator pursu-
ant to Sec. 107 of the Clean Air Act,
for air quality planning purposes.
40 CFR 81
*Clean Air Act
                                      A-2

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      Term

ALLOWABLE
EMISSIONS
               Definition

The emission rate calculated using the
maximum rated capacity of the source
(unless the source is subject to en-
forceable permit conditions which limit
the operating rate or hours of operation
or both) and the most stringent of the
following:
   (i) Applicable standards as set forth
in 40 CFR Part 60 and Part 61 (NSPS,
NESHAPS),
   (ii) The applicable State Implementa-
tion Plan emission limitation, or
   (iii) The emission rate specified as
a permit condition.
    Reference
40 CFR 51.23
ALTERNATIVE
METHOD
AMBIENT AIR
Any method of sampling and analyzing for
an air pollutant which is not a refer-
ence or equivalent method but which has
been demonstrated to the Administrator's*
satisfaction to, in specific cases, pro-
duce results adequate for his determina-
tion of compliance.

That portion of the atmosphere external
to buildings to which the general public
has access.
40 CFR 60.2
40 CFR 50.1
AREA SOURCE
Any small residential, governmental,
institutional, commercial, or industrial
fuel combusion operations; onsite solid
waste disposal facility; motor vehicles,
aircraft, vessels, or other transporta-
tion facilities; or other miscellaneous
sources such as those listed in Appendix
D of 40 CFR 51, and as identified
through inventory techniques similar to
those described in:  "A Rapid Survey
Technique for Estimating Community Air
Pollution Emissions,"  Public Health
Service Publication No. 999-AP-29,
October 1966.
40 CFR 51.1
*Administrator of EPA.
                                    A-3

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      Term
               Definition
    Reference
AREA SOURCE
  (cont.)
           APPENDIX D LISTING

(i) Fuel combustion — stationary source:  40 CFR 51.1

    Anthracite coal, bituminous coal,
    distillate oil, residual oil, natural
    gas, wood, process gas (industrial)

(ii) Process losses
(iii) Solid wate disposal:

    Incineration, open burning, dumps

(iv) Transportation:

    Motor vehicles (gasoline and diesel
    powered), off-highway use, aircraft,
    railroads, vessels,  gasoline hand-
    ling evaporative losses

(v) Miscellaneous sources:

    Forest fires, structural fires, coal
    refuse burning, agricultural burning
ASBESTOS
Actinolite, amosite, anthophyllite,
chrysotile, crocidolite, tremolite.
40 CFR 61.21
BASELINE
CONCENTRATION
That ambient concentration level which
exists at the time of the applicable
baseline date, minus any contribution
from major stationary sources and major
modifications on which construction com-
menced on or after January 6, 1975.  The
baseline concentration shall include con-
tributions from:
(i) The actual emissions of other sources
in existence on the applicable baseline
date, except that contributions from such
existing sources to the extent that a
plan revision proposing less restrictive
requirements affects such sources was
submitted on or before the baseline date
and was pending action by the Administra-
tor on that date shall be determined from
the allowable emissions under the plan,
as revised; and
40 Part 51.24
                                      A-4

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      Term
               Definition
    Reference
                  (ii) The allowable emissions of major sta-
                  tionary sources and major modifications
                  which commenced construction before Janu-
                  ary 6, 1975, but were not in operation by
                  the applicable baseline date.
BASELINE DATE
For every part of an Air Quality Control
Region  (AQCR) designated as unclassifi-
able or attainment under Section 107(d)
(1)(D) or (E) of the Act the date of the
first complete application after August
7, 1977 for a permit under this section
for any major stationary source or major
modification in any part of the AQCR.
40 CFR 51.24
BERYLLIUM
The element beryllium.  Where weights or
concentrations are specified, such weights
or concentrations apply to beryllium only,
excluding the weight or concentration of
any associated elements.
40 CFR 61.81
BEST AVAILABLE
CONTROL
TECHNOLOGY
(BACT)
An emission limitation (including a vis-
ible emission standard) based on the
maximum degree of reduction for each pol-
lutant subject to regulation under the
Act which would be emitted from any pro-
posed major stationary source or major
modification which the permitting author-
ity, on a case-bv~case basis, taking into
account energy, environmental, and eco-
nomic impacts and other costs determines
is achievable for such source or modifi-
cation through application of production
processes or available methods, systems,
and techniques, including fuel cleaning
or treatment or innovative fuel combus-
tion techniques for control of such pol-
lutant.  In no event shall application
of the best available control technology
result in emissions of any pollutant
which would exceed the emissions allowed
by any applicable standard under 40 CFR
Part 60 and Part 61.  If the reviewing
agency determines that technological or
economic limitations on the application
of measurement methodology to a particu-
lar class of sources would make the
40 CFR 51.24
                                     A-5

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      Term
              Definition

imposition of an emission standard infeas-
ible, it may instead prescribe a design,
equipment, work practice or operational
standard, or combination thereof, to re-
quire the application of best available
control technology.  Such standard shall,
to the degree possible, set forth the
emission reduction achievable by imple-
mentation of such design, equipment, work
practice or operation and shall provide
for compliance by means which achieve
equivalent results.
    Reference
CAPITAL
EXPENDITURE
An expenditure for a physical or opera-
tional change to an existing facility
which exceeds the product of the applic-
able "annual asset guideline repair allow-
ance percentage" specified in the latest
edition of Internal Revenue Service Pub-
lication 534 and the existing facility's
basis, as defined in section 1012 of the
Internal Revenue Code.
40 CFR 60.2
COAL
Coal or coal derivatives.
40 CFR 55.02
COMMENCE
As applied to construction of a major
stationary source or major modification
means that the owner or operator has all
necessary preconstruction approvals and
either has:
(i) Begun, or caused to begin, a contin-
uous program of physical onsite construc-
tion of the source to be completed within
a reasonable time; or
(ii) Entered into binding agreements or
contractual obligations, which cannot be
cancelled or modified without substantial
loss to the owner or operator, to under-
take a program of construction of the
source to be completed within a reason-
able time.
40 CFR 51.24
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      Term

COMPLIANCE
SCHEDULE
               Definition

The date or dates by which a source or
category of sources is required to com-
ply with specific emission limitations
contained in an implementation plan and
with any increments of progress toward
such compliance.
    Reference
40 CFR 51.1
CONDENSATE        Hydrocarbon liquid separated from natural
(OF HYDROCARBONS) gas which condenses due to changes in the
                  temperature and/or pressure and remains
                  liquid at standard conditions.
                                           40 CFR 60.11
CONSTRUCTION
Fabrication, erection, or installation
of a stationary source.
40 CFR 61.02
CONTROL STRATEGY
A combination of measures designated to
achieve the aggregate reduction of emis-
sions necessary for attainment and main-
tenance of a national standard, including,
but not limited to, measures such as:
   (1) Emission limitations
   (2) Federal or State emission charges
or taxes or other economic incentives or
disincentives.
   (3) Closing or relocation of residen-
tial, commercial, or industrial facilities,
   (4) Changes in schedules or methods of
operation of commercial or industrial
facilities or transportation systems, in-
cluding, but not limited to, short-term
changes made in accordance with standby
plans.
   (5) Periodic inspection and testing of
motor vehicle emission control systems,
at such time as the Administrator deter-
mines that such programs are feasible
and practicable.
   (6) Emission control measures applic-
able to in-use motor vehicles, including,
but not limited to, measures such as man-
datory maintenance, installation of emis-
sion control devices, and conversion to
gaseous fuels.
40 CFR 51.1
                                    A-7

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      Term
                Definition
    Reference
CONTROL STRATEGY
    (cont.)
   (7) Measures to reduce motor vehicle
traffic, including, but not limited to,
measures such as commuter taxes, gasoline
rationing; parking restrictions, or stag-
gered working hours.
   (8) Expansion or promotion of the use
of mass transportation facilities through
measures such as increases in the fre-
quency, convenience, and passenger-
carrying capacity of mass transporation
systems or providing for special bus
lanes on major streets and highways.
   (9) Any land use or transportation
control measures not specifically delin-
eated herein.
   (10) Any variation of, or alternative
to any measure delineated herein.
   (11) Control or prohibition of a fuel
or fuel additive used in motor vehicles,
if such control or prohibition is neces-
sary to achieve a national primary or
secondary air quality standard and is
approved by the Administrator under
Section 211(c)(l)(C) of the Clean Air
Act,
40 CFR 51.1
CRANKCASE
EMISSIONS
Airborne substances emitted to the atmo-
sphere from any portion of the engine
crankcase ventilation or lubrication
systems,
40 CFR 85.002
CRITERIA
POLLUTANT
Any air pollutant for which national
primary and secondary ambient air quality
standards have been promulgated, in-
cluding:  sulfur oxides, particulate
matter, carbon monoxide, ozone, hydro-
carbons, nitrogen dioxide, and  lead.
Clean Air Act,
Sec. 109
40 CFR 50.5
40 CFR 50.6
40 CFR 50.7
40 CFR 50.8
40 CFR 50.9
40 CFR 50.10
40 CFR 50.11
40 CFR 50.12
                                     A-8

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      Term

EMERGENCY
RENOVATION
                Definition

A renovation operation that results from
a sudden, unexpected event, and is not a
planned renovation.  Operations necessi-
tated by nonroutine failures of equip-
ment are included.
    Reference
40 CFR 61.21
EMISSION
The act of releasing or discharging air
pollutants into the ambient air from any
source.
40 CFR 51.328
EMISSION FACTOR
An estimate of the rate at which a pollu-  AP-42
tant is released to the atmosphere as a
result of some activity, such as combus-
tion or industrial production, divided
by the level of that activity.
EMISSION UNIT
Any part of a stationary source which
emits or has the potential to emit any
pollutant regulated under the Clean Air
Act.
40 CFR 51.24
EQUIVALENT
METHOD
A method of sampling and analyzing the
ambient air for an air pollutant that
has been designated as an equivalent
method in accordance with this part; it
does not include a method for which an
equivalent method designation has been
cancelled in accordance with § 53.11 or
§ 53.16 of 40 CFR 53.
40 CFR 53.1
EXHAUST EMISSIONS Substances emitted to the atmosphere
                  from any opening downstream from the
                  exhaust port of a motor vehicle engine.
                                           40 CFR 85.002
                                    A-9

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      Term
EXISTING SOURCE
               Definition

Any stationary source other than a new
source.
    Reference

Clean Air Act
Sec. Ill a(6)
FACILITY
An identifiable piece of process equip-
ment.  A stationary source is composed
of one or more pollutant-emitting
facilities.
40 CFR 51.24
FLOATING ROOF
A storage vessel cover consisting of a     40 CFR 60.111
double deck, pontoon single deck, internal
floating cover or covered floating roof,
which rests upon and is supported by the
petroleum liquid being contained, and is
equipped with a closure seal or seals to
close the space between the roof edge and
the tank wall.
FOSSIL FUEL
Natural gas, petroleum, coal, and any
form of solid, liquid, or gaseous fuel
derived from such material for the pur-
pose of creating useful heat.
40 CFR 60.41a
FRIABLE ASBESTOS
MATERIAL
Any material that contains more than 1     40 CFR 61.21
percent asbestos by weight and that can be
crumbled, pulverized, or reduced to powder,
when dry, by hand pressure.
FUEL-BURNING
EQUIPMENT
Any furnace, boiler, apparatus, stack, and 40 CFR 51.328
all appurtenances thereto, used in the pro-
cess of burning fuel for the primary pur-
pose of producing heat or power by indirect
heat transfer.
FUEL EVAPORATIVE
EMISSIONS
Vaporized fuel emitted into the atmosphere 40 CFR 85.0021
from the fuel system of a motor vehicle.
FUGITIVE EMISSIONS Those emissions which do not pass through  40 CFR 51.24
                   a stack, chimney, vent, or other function-
                   ally equivalent opening.
                                     A-10

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      Term
               Definition
    Reference
GASOLINE
Any fuel sold in any state for use in
motor vehicles and motor vehicle engines.
and commonly or commercially known or
sold as gasoline.
   (a) "Leaded gasoline" means gasoline
which is produced with the use of any
lead additive or which contains more
than 0.5 grams of lead per gallon or
more than .005 grams of phosphorus per
gallon.
   (b) "Unleaded gasoline" means gaso-
line containing not more than .05 grams
of lead per gallon and not more than
.005 grams of phosphorus per gallon.
40 CFR 80.2
HAZARDOUS AIR
POLLUTANT
An air pollutant to which no ambient
air quality standard is applicable and
which in the judgment of the administra-
tor causes, or contributes to, air pollu-
tion which may reasonably be anticipated
to result in an increase in mortality or
an increase in serious irreversible, or
incapacitating reversible, illness.
Clean Air Act
Sec. 112 (a)(l)
HAZARDOUS AND
TRACE EMISSIONS
SYSTEM (HATREMS)
Data base system developed to calculate
and store emissions data for lead as well
as other possible future criteria pollu-
tants.  HATREMS utilizes NEDS data includ-
ing emission factors, default multiplier
units, control efficiency multiplier.
EPA-450/2-78-038
HOT SOAK LOSS
Fuel evaporative emissions during the 1
hour hot soak period which begins imme-
diately after the engine is turned off.
40 CFR 85.002
HYDROCARBON
Any organic compound consisting predomi-
nantly of carbon and hydrogen.
40 CFR 60.111
INCREMENTS OF
PROGRESS
Steps toward compliance which will be
taken by a specific source, including:
   (1) Date of submittal of the source's
final control plan to the appropriate air
pollution control agency;
40 CFR 51.1
                                     A-ll

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      Terms
               Definition                      Reference

   (2) Date by which contracts for emis-
sion control systems or process modifica-
tions will be awarded; or date by which
orders will be issued for the purchase of
component parts to accomplish emission
control or process modification;
   (3) Date of initiation of on-site con-
struction or installation of emission con-
trol equipment or process change;
   (4) Date by which on-site construction
or installation of emission control equip-
ment or process modification is to be com-
pleted; and
   (5) Date by which final compliance is
to be achieved.
INDIRECT SOURCE
Facility, building, structure or installa- Clean Air Act
tion, real property, road or highway which (42 U.S.C. 1857
attracts, or may attract, mobile sources of   Seq) Sec. 110
pollution; i.e., parking lots, parking ga-
rages, facilities subject to any measure
for management of parking supply, including
regulation of existing off-street parking
but such term does not include new or
existing on-street parking.
INDIRECT SOURCE
A facility, building, structure, or in-
stallation which attracts or may attract
mobile source activity that results in
emissions of a pollutant for which there
is a national standard.  Such indirect
sources include, but are not limited to:
   (a) Highways and roads
   (b) Parking facilities.
   (c) Retail, commercial and industrial
facilities.
   (d) Recreation, amusement, sports
and entertainment facilities.
   (e) Airports.
   (f) Office and Government buildings.
   (g) Apartment and condominium
buildings.
   (h) Education facilities.
40 CFR 52.22
                                     A-12

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      Terms
               Definition
   Reference
 INNOVATIVE
 CONTROL
 TECHNOLOGY
Any system of air pollution control that
has not been adequately demonstrated in
practice, but would have a substantial
likelihood of achieving greater continu-
ous emission reduction than any control
system in current practice or of achiev-
ing at least comparable reductions at
lower cost in terms of energy, economics,
or nonair quality environmental impacts.
40 CFR 51.24
1SOKINETIC
SAMPLING
Sampling in which the linear velocity of
the gas entering the sampling nozzle is
equal to that of the undisturbed gas
stream at the sample point.
40 CFR 60.2
LOWEST ACHIEVABLE
EMISSION RATE
(LAER)
For any source, that rate of emission
based on the following, whichever is
more stringent:
   (i) The most stringent emission limita-
tion which is contained in the implementa-
tion plan of the State for such class or
category of source, unless the owner or
operator of the proposed source demon-
strates that such limitations are not
achievable; or
  (ii) The most stringent emission limita-
tion which is achieved in practice by such
class or category of source.
   This term, applied to a modification,
means the lowest achievable emission rate
for the new or modified facilities within
the source.  In no event shall the appli-
cation of this term permit a proposed new
or modified facility to emit any pollutant
in excess of the amount allowable under
applicable new source standards of
performance.
40 CFR 51.328
MAJOR MODIFICATION Any physical change in or change in the
                   method of operation of a major stationary
                   source, or series of contemporaneous phys-
                   ical changes in or changes in the method of
                   operation of a major stationary source, that
                   would result in a significant net increase
                   in that sources potential to emit the pollu-
                   tant for which the stationary source is major
                   (or that would make the stationary source
                                     A-13

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Terms                       Definition                      Reference

             major taking into account all accumulated
             net increases in potential emissions occur-
             ing at the source, including any initial
             construction since August 7, 1977).   The
             term "major modification" serves as  the
             definition of "modification" or "modified"
             when used in the Clean Air Act in reference
             to a major stationary source.
                (ii) A physical change shall not  include
             routine maintenance, repair and replacement.
               (iii) A change in the method of operation,
             unless previously limited by enforceable
             permit conditions, shall not include:
                (a) Use of an alternative fuel or raw
             material by reason of an order under
             sections 2(a) and (b) of the Energy  Supply
             and Environmental Coordination Act of 1974
             (or any superseding legislation), a  prohi-
             bition under the Power Plant and Industrial
             Fuel Use Act of 1978 (or any superseding
             legislation), or by reason of a natural gas
             curtailment plan pursuant to the Federal
             Power Act;
                (b) Use of an alternative fuel or raw
             material, if prior to January 6, 1975, the
             source was capable of accommodating  such
             fuel or material;
                (c) Use of an alternative fuel by reason
             of an order or rule under section 125 of
             the Clean Air Act;
                (d) Change in ownership of the stationary
             source; or
                (e) Use of refuse derived fuel generated
             from municipal solid waste.
                (iv) Changes are "contemporaneous" only
             if reductions occur after a notice is filed
             pursuant to paragraph (v)(4) and before
             operation of the emission unit or units that
             will result in emission increases.  Also, to
             be "contemporaneous" all of the emission re-
             ductions must be completed and enforceable
             under the state plan before operation of
             the emission unit or units that will result
             in any emission increase.  Where the new
             emission unit is a replacement for an emis-
             sion unit that is being shut down in order
             to provide the necessary reductions, the
             reviewing authority may allow up to  180 days
             for shakedown or the new emission unit be-
             fore the existing emission unit is required
             to cease operation.

                                A-14

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      Term                        Definition                      Reference

                      (v) For a series of changes in a sta-
                   tionary source to satisfy the requirement
                   of "no net increase," all of the following
                   must be satisfied:
                      (a) All reductions and all increases
                   must be for the same pollutant;
                      (b) The sum of all decreases  must be
                   greater than or equal to the sum of all
                   increases;
                      (c) On balance the air quality of the
                   affected area must not be adversely
                   impacted.
                     (vi) In performing the calculation in
                   paragraph (b)(2)(v) of this section to
                   determine whether the sum of all decreases
                   is greater than or equal to the  sum of all
                   increases) the following rules shall apply:
                      (a) Subject to the following  adjustments,
                   the size of an increase or decrease is de-
                   termined by the difference between the poten-
                   tial to emit of the change of emissions unit
                   before and after the change.
                      (b) If potential to emit for  a changed
                   emission unit was initially higher than
                   allowable emissions, then no offset credit
                   may be taken for decreasing potential to
                   emit down to allowable emissions.
                      (c) The requirement of 40 CFR Part 51,
                   Appendix S, Sections IV. C. 2 and 4 shall
                   apply involving the amount of credit per-
                   missible for changing fuels and  for replac-
                   ing one hydrocarbon compound with another
                   of lesser reactivity.
MAJOR STATIONARY      (i) Any of the following stationary     40 CFR 51.24
SOURCE             sources of air pollutants which emit,  or
                   have the potential to emit, 100 tons per
                   year or more of any pollutant regulated
                   under the Clean Air Act (the "Act"):
                   Fossil fuel-fired steam electric plants of
                   more than 250 million British thermal units
                   per hour heat input, coal cleaning plants
                   (with thermal dryers),  kraft pulp mills,
                   Portland cement plants, primary zinc smel-
                   ters, iron and steel mill plants, primary
                   aluminum ore reduction plants,  primary
                   copper smelters,  municipal incinerators
                   capable of charging more than 250 tons of
                   refuse per day, hydrofluoric, sulfuric,


                                      A-15

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      Terms
MALFUNCTION
               Definition                      Reference

and nitric acid plants, petroleum refin-
eries, lime plants, phosphate rock pro-
cessing plants, coke oven batteries, sul-
fur recovery plants, carbon black plants
(furnace process), primary lead smelters,
fuel conversion plants, sintering plants,
secondary metal production plants, chemical
process plants, fossil-fuel boilers (or
combination thereof) totaling more than
250 million British thermal units per hour
heat input, petroleum storage and transfer
ore processing plants, glass fiber process-
ing plants, and charcoal production plants;
  (ii) Notwithstanding the stationary source
sizes specified in paragraph (b)(l)(i) of
this section, any stationary source which
emits, or has the potential to emit, 250
tons per year or more of any air pollutant
regulated under the Act.

Any sudden and unavoidable failure of air  40 CFR 60.2
pollution control equipment or process to
operate in a normal or usual manner.  Fail-
ures that are caused entirely or in part by
poor maintenance, careless operation, or any
other preventable upset condition or prevent-
able equipment breakdown shall not be consid-
ered malfunctions.
MERCURY
The element mercury, excluding associated  40 CFR 61.51
elements, and includes mercury in particu-
lates, vapors, aerosols, and compounds.
MOBILES SOURCES
Including:  light-duty gasoline powered
vehicles; light-duty diesel powered
vehicles; light-duty and heavy-duty gas-
oline powered trucks; heavy-duty diesel
powered vehicles; gaseous fueled vehicles;
motorcycles; aircraft; locomotives; in-
board and outboard powered vessels; agri-
cultural equipment; heavy-duty construction
equipment; snow mobiles; small, general
utility engines.
Compilation of
Air Pollution
Emission Factors
(AP-42)
                                     A-16

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       Terms
               Definition
    Reference
MODEL YEAR
The manufacturer's annual production period
(as determined by the Administrator) which
includes January 1 or such calendar year:
provided, that if the manufacturer has no
annual production period, the term "model
year" shall mean the calendar year.
  40 CFR 85.1021
MODIFICATION
Any physical change in, or change in method  Clean Air Act
of operation of, a stationary source which   Sec. lll(a)(4)
increases the amount of any air pollutant
emitted by such source or which results in
the emission of any air pollutant not pre-
viously emitted.
NATIONAL PRIMARY
AMBIENT AIR
QUALITY STANDARDS
Ambient air quality standards the attain-
ment and maintenance of which in the judg-
ment of the Administrator (of US EPA), based
on such criteria and allowing an adequate
margin of safety, are requisite to protect
the public health.
  Clean Air Act
  Sec. 109(b)(l)
NATIONAL SECONDARY A level of air quality the attainment and
AMBIENT AIR
QUALITY STANDARDS
maintenance of which in the judgment of the
Administrator, based on such criteria, is
is requisite to protect the public welfare
from any known or anticipated adverse effects
associated with the presence of such air
pollutant in the ambient air.
  Clean Air Act
  Sec. 109(b)(2)
NECESSARY
RECONSTRUCTION
APPROVALS OR
PERMITS
Those permits or approvals required under  40 CFR 51.24
Federal air quality control laws and regu-
lations and those air quality control laws
and regulations which are part of the ap-
plicable State Implementation Plan.
NEW SOURCE
Any stationary source, the construction
or modification of which is commenced
after the publication of regulations
prescribing a standard or performance
applicable to the source.
                                                              Clean Air Act
                                                              Sec.  lll(a)(2)
NITROGEN OXIDES
All oxides of nitrogen except nitrous
oxide, as measured by test methods set
forth in this part.
40 CFR 60.2
                                      A-17

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       Terms

NON ATTAINMENT
AREA
                                  Definition
                                               Reference
Any air pollutant an area which is shown   Clean Air Act
by monitored data or which is calculated   Sec. 171(a)(2)(I)
by air quality modeling to exceed any                   (2)
National Ambient Air Quality Standard for
such pollutant.
OPACITY
A state which renders material partially
or wholly impervious to rays of light and
causes obstruction of an observer's view.
Env. Rpt. 125-0132
OPACITY
The fraction of a beam of light, expres-
sed in percent, which fails to penetrate
a plume of smoke.
40 CFR 86.077-2
OWNER OR OPERATOR
Any persons who owns, leases, operates,    40 CFR 51.1
controls, or supervises a facility, build-
ing, structure, or installation which di-
rectly or indirectly results or may result
in emissions of any air pollutant for which
a national standard is in effect.
PARTICULATE MATTER Any finely divided solid or liquid mater-
                   ial, other than uncombined water, as mea-
                   sured by the reference methods specified
                   under each applicable subpart, or an
                   equivalent or alternative method.
                                           40 CFR 60.2
PERSON
An  individual, corporation, partnership,   Clean Air Act
association, state, municipality, politi-  Sec. 302 (e)
cal subdivision of a state, and any agency,
department, or instrumentality of the
United States and any officer, agent, or
employee thereof.
PETROLEUM
The crude oil removed from the earth and
the oils derived from tar sands, shale,
and coal.
40 CFR 60.101
                                       A-18

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       Terms

PHOTOCHEMICAL
OXIDANTS
               Definition
    Reference
Products of atmospheric reactions involv-  Env. Rpt. 31:2151
ing organic pollutants, nitrogen oxides
(NOX), oxygen, and sunlight.  They consist
mostly of ozone, N02, and peroxyacylnitrates
and other peroxy compounds, and are formed
along with other photochemical products,
such as aldehydes, nitrous acid, nitric acid,
and formic acid.  They originate mainly from
volatile organic and NOX emissions produced
by human activities.  Photochemical oxidant
formation is a complex function of emissions
and meterological patterns.
POINT SOURCE
   (1) For particulate matter, sulfur
oxides, carbon monoxide, hydrocarbons,
and nitrogen dioxide —
   (i) Any stationary source the actual
emissions of which are in excess of 90.7
metric tons (100 tons) per year of the
pollutant in a region containing an area
whose 1970 "urban place" population, as
defined by the U.S. Bureau of the Census,
was equal to or greater than 1 million;
  (ii) Any stationary source the actual
emissions of which are in excess of 22.7
metric tons (25 tons) per year of the
pollutant in a region containing an area
whose 1970 "urban place" population, as
defined by the U.S. Bureau of Census was
less than 1 million; or
 (iii) Without regard to amount of emis-
sions, stationary sources such as those
listed in Appendix C of 40 CFR Part 51.
   (2) For lead, any stationary source the
actaul emissions of which are in excess of
4.54 metric tons (5 tons) per year of lead
or lead compounds measured as elemental
lead.

           APPENDIX C LISTING
       CHEMICAL PROCESS INDUSTRIES

Adipic acid.
Ammonia.
Ammonium nitrate.
Carbon black.
Charcoal.
Chlorine.
Detergent and soap.
40 CFR 51.1
                                    A-19

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Terms                      Definition                      Reference

            Explosives (TNT and
            Hydrofluoric acid.
            Nitric acid.
            Paint and varnish manufacturing.
            Phosphoric acid.
            Phthalic anhydride.
            Plastics manufacturing.
            Printing ink manufacturing.
            Sodium carbonate.
            Sulfuric acid.
            Synthetic fibers.
            Synthetic rubber.
            Terephthalic acid.
                FOOD AND AGRICULTURAL INDUSTRIES
            Alfalfa dehydrating.
            Ammonium nitrate.
            Coffee roasting.
            Cotton ginning.
            Feed and grain.
            Fermentation processes.
            Fertilizers.
            Fish meal processing.
            Meat smoke houses.
            Starch manufacturing.
            Sugar cane processing.
                    METALLURGICAL  INDUSTRIES
            Primary metals  industries:
               Aluminum ore reduction.
               Copper smelters.
               Ferroalloy production.
               Iron and steel mills.
               Lead smelters.
               Metallurgical  coke  manufacturing.
               Zinc.
            Secondary metals  industries:
               Aluminum operations.
               Brass and bronze smelting.
               Ferroalloys.
               Gray iron foundries.
               Lead smelting.
               Magnesium smelting.
               Steel foundries.
               Zinc processes.
                             A-20

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       Terms                      Definition                      Reference

                          MINERAL PRODUCTS INDUSTRIES

                   Asphalt roofing.
                   Asphaltic  concrete batching.
                   Bricks  and related clay refractories.
                   Calcium carbide.
                   Castable refractories.
                   Cement.
                   Ceramic and clay  processes.
                   Clay and fly ash  sintering.
                   Coal cleaning.
                   Concrete batching.
                   Fiberglass manufacturing.
                   Frit manufacturing.
                   Glass manufacturing.
                   Gypsum  manufacturing.
                   Lime manufacturing.
                   Mineral wool manufacturing.
                   Paperboard manufacturing.
                   Perite  manufacturing.
                   Phosphate  rock preparation.
                   Rock, gravel,  and sand  quarrying  and  pro-
                   cessing.
                     PETROLEUM REFINING AND PETROCHEMICAL
                                  OPERATIONS
                                WOOD PROCESSING
                      PETROLEUM STORAGE  (Storage  tanks and
                                        bulk terminals)

                                 MISCELLANEOUS

                   Fossil  fuel steam electric powerplants.
                   Municipal  or equivalent.incinerators.
                   Open burning dumps.


POTENTIAL TO       The capability at maximum design  capacity   40  CFR  51.24
EMIT               to emit a  pollutant after the  application
                   of air  pollution  control equipment.   An-
                   nual potential  shall be based  on the maxi-
                   mum annual rated  capacity of the  stationary
                   source  assuming continuous year round oper-
                   ation.   Enforceable permit conditions on
                   the type of materials combusted or processed
                   may be  used in determining the annual poten-
                   tial.   Secondary  emissions do  not  count in
                   determining annual potential.  Fugitive
                   emissions  also  do not count, except with
                   respect to the  following stationary sources
                   and then only  to  the extent quantifiable:
                                   A-21

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       Terms

 POTENTIAL TO
 EMIT (cont.)
               Definitions

   (i) Coal cleaning plants
   (ii) Kraft pulp mills
   (iii) Portland cement plants
   (iv) Primary zinc smelters
   (v) Iron and steel mill plants
   (vi) Primary aluminum ore reduction
plants
   (vii)  Primary copper smelters
   (viii)  Municipal incinerators
   (ix) Hydrofluoric, sulfuric, or nitric
acid plants
   (x) Petroleum refineries
   (xi) Lime plants
   (xii)  Phosphate rock processing plants
   (xiii)  Coke oven batteries
   (xiv)  Sulfur recovery plants
   (xv) Carbon black plants
   (xvi)  Primary lead smelters
   (xvii)  Fuel conversion plants
   (xviii)  Sintering plants
   (xix)  Secondary metal production
plants
   (xx) Chemical process plants
   (xxi)  Fossil fuel-fired boilers
   (xxii)  Petroleum storage and transfer
units
   (xxiii) Taconite ore processing plants
   (xxiv) Glass fiber processing plants
   (xxv) Charcoal production plants
   (xxvi) Fossil  fuel-fired steam electric
plants
   (xxvii) Any other stationary source cate-
gory which, at the time of the applicability
determination, is being regulated under
Section 111 or 112 of the  Clean Air  Act.
Reference
PRIMARY STANDARD
A national primary  ambient  air  quality
standard  promulgated  pursuant  to  Section
109  of  the Clean Air  Act.
                                                              (FED) 40 CFR 5.1.
PROPORTIONAL
SAMPLING
 Sampling  at  a  rate that  produces  a con-
 stant  ratio  of sampling  rate to stack gas
 flow rate.
                                                              40 CFR 60.2
                                     A-22

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       Terms
               Definition
   Reference
REASONABLY
AVAILABLE
CONTROL
TECHNOLOGY
(RACT)
Devices,  systems, process modifications,   40 CFR 51.1
or other  apparatus or techniques, the
application of which will permit attain-
ment of the emission limitations set forth
in Appendix B to 40 CFR 51, provided that
Appendix  B to 40 CFR 51 is not intended,
and shall not be construed, to require or
encourage State agencies to adopt such emis-
sion limitations without due consideration
of (1) the necessity of imposing such emis-
sion limitations in order to attain and
maintain  a national standard, (2) the social
and economic impact of such emission limita-
tions, and (3) alternative means of providing
for attainment and maintenance of such
national  standards.
RECONSTRUCTION
Will be presumed to have taken place
where the fixed capital cost of the new
components exceeds 50 percent of the
fixed capital cost of a comparable en-
tirely new stationary source.  However,
any decision as to whether reconstruction
has occurred will be made in accordance
with the provisions of 40 CFR 60.15(l)-(3) .
A reconstructed stationary source will be
treated as a new stationary source for pur-
poses of this section, except that use of
an alternative fuel or raw material by rea-
son of an order in effect under Sections
2(a) and (b) of the Energy Supply and Envi-
ronmental Coordination Act of 1974 (or any
superseding legislation), by reason of a
natural gas curtailment plan in effect pur-
suant to the Federal Power Act, or by rea-
son of an order or rule under Section 125
of the Act, shall not be considered recon-
struction.  In determining best available
control technology for a reconstructed
stationary source, the provisions of 40
CFR 60.15(f)(4) shall be taken into account
in assessing whether a standard of perform-
ance under 40 CFR Part 60 is applicable
to each stationary source.
40 CFR 51.24
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       Terms
REFERENCE METHOD
               Definition

A method of sampling and analyzing the
ambient air for an air pollutant that is
specified as a reference method in an
Appendix to Part 50 of 40 CFR 53, or a
method that has been designated as a
reference method in accordance with this
part; it does not include a method for
which a reference method designation has
been cancelled in accordance with § 53.11
or § 53.16 of 40 CFR 53.
    Reference
40 CFR 53.1
REGION
   (1) An air quality control region
designated by the Secretary of Health,
Education, and Welfare or the Administra-
tor,  (2) any area designated by a State
agency as an air quality control region
and approved by the Administrator, or
(3) any area of a State not designated as
an air quality control region under sub-
paragraph (1) or (2) of this paragraph.
40 CFR 51.1
REGIONAL
LIMITATION
The requirement that a source which is     40 CFR 55
located in an air quality control region
in which a national primary ambient air
quality standard for an air pollutant is
being exceeded in that region, may not
emit such pollutant in amounts which ex-
ceed any emission limitation  (and may not
violate any other requirement) which applies
to such source, under the applicable
implementation plan for such pollutant.
REID VAPOR
PRESSURE
The absolute vapor pressure of volatile
crude oil and volatile non-viscous petro-
leum liquids, except liquified petroleum
gases, as determined by ASTM-D-323-58 (re-
approved 1968).
40 CFR 60.111
ROADWAYS
Surfaces on which motor vehicles travel
including, but not limited to, highways,
roads, streets, parking areas, and
driveways.
40 CFR 61.21
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       Terms                      Definition                      Reference

SECONDARY          Emissions which occur or would occur as a  40 CFR 51.24
EMISSIONS          result of the construction or operation
                   of a major stationary source or major mod-
                   ification, but do not necessarily come from
                   the major stationary source or major modi-
                   fication itself.   For purposes of this sec-
                   tion, secondary emissions must be specific
                   and well defined, must be quantifiable, and
                   must impact the same general area as the
                   secondary source or modification which causes
                   the secondary emissions.   Secondary emissions
                   may include but are not limited to:
                      (i) Emissions from ships or trains coming
                   to or from the stationary source or modifi-
                   cation;  and
                      (ii)  Emissions from any offsite support
                   source which would be constructed or would
                   not otherwise increase its emissions.
SECONDARY STANDARD A national secondary ambient  air  quality    40  CFR  51.1
                   standard promulgated pursuant to  Section
                   109 of the Clean Air Act.
SMALL REFINERY     A refinery:                                 40  CFR  80.2
                      (1)  Which  has  a crude  oil  or  bona  fide
                   feed stock capacity of  50,000 barrels  per
                   day or  less,  and
                      (2)  Which  is not owned or  controlled  by
                   any refiner with  a total  combined  crude  oil
                   or bona fide  feed stcek capacity greater
                   than 137,500  barrels per  day.
                   "Owned  or controlled" means leased,  operated,
                   controlled, supervised, or in ten  percent  or
                   greater part, owned.
                   Crude oil or  bona fide feed stock  capacity
                   means that crude  oil or bona fide  feed stock
                   capacity certified by the Department of
                   Energy, Office of Refining Operations.
                                     A-25

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       Terms
               Definition
    Reference
 SOLID-DERIVED
 FUEL
Any solid, liquid, or gaseous fuel derived 40 CFR 60.41a
from solid fuel for the purpose of creating
useful heat and includes, but is not limited
to, solvent refined coal, liquified coal,
and gasified coal.
SOURCE
Any structure, building, facility, equip-  40 CFR 51.24
ment, installation or operation (or com-
bination thereof) which is located on one or
more contiguous or adjacent properties and
which is owned or operated by the same per-
son (or by persons under common control).
SOURCE
CLASSIFICATION
CODES (SCC)
Code giving specific identification of
the source, and defining the units of
activity level, and emission factors re-
lated to point source activity levels.
Emissions may be calculated by multiplying
emission factor for each SCC and the
activity level.
EPA-450/2-78-026
STACK
Any chimney flue, conduit, or duct arranged  40 CFR 51.328
to conduct emissions to the ambient air.
STACK DIAMETER
The inside diameter of a round gas exit
at the point of emission; for non-circu-
lar exits, it is an equivalent diameter
calculated from the cross-section area
at the point of discharge.
   Equivalent Diameter =/1.128  Area
APTD-1135
STACK HEIGHT
The vertical distance between the point
of emission and ground level.
APTD-1135
STACK EXHAUST
FLOW RATE
The total volume of exhaust gas released   APTD-1135
at the operating temperature of the stack;
design or maximum exhast-gas volume.
STACK TEMPERATURE
The  temperature of  the exhaust stream at   APTD-1135
the  stack exit reported in degrees Fahren-
heit under normal operating conditions.
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       Terms
               Definition
    Reference
STANDARD
CONDITIONS
STANDARD
INDUSTRIAL
CLASSIFICATION
(SIC)
A dry gas temperature of 70° Fahrenheit    40 CFR 51.328
and a gas pressure of 14.7 pounds per
square inch absolute, or 293° Kelvin and
a pressure of 101.3 kilopascale (29.92
inches of Hg).   Note that other definitions
have been specified by EPA.

The classification of establishments by    Standard
type of activity in which  (it is) engaged; Industrial
for purposes of facilitating the collec-
tion, tabulation, presentation, and
analysis of data relating  to establish-
ments.  Classification of  establishments
by industry on a two-digit, a three-digit,
or a four-digit basis.
Classification
Manual
STANDARD OF
PERFORMANCE
Requirement of continuous emission reduc-
tion, including any requirement relating
to the operation or maintenance of a
source to assure continuous emission
reduction.
Clean Air Act
Sec. 302 (1)
STATE
IMPLEMENTATION
PLAN (SIP)
The plan including the most recent revi-
sion thereof, which has been approved or
promulgated by the Administrator under
Section 110 of the Act (Clean Air Act),
and which implements the requirements of
Section 110.
40 CFR 65.02
STARTUP
The setting in operation of a stationary
source for any purpose.
40 CFR 61.02
STATIONARY SOURCE  Any structure, building,  facility or in-
                   stallation which emits or may emit any
                   air pollutant regulated under the Clean
                   Air Act.
                                           40 CFR 51.24
STATIONARY SOURCE
FUEL OR EMISSION
LIMITATION
Any emission limitation, schedule or time- 40 CFR 55,02
table of compliance, or other requirement,
which is prescribed under the Clean Air
Act (other than Section 119, Section lll(b),
Section 112 or Section 303 of the Act) or
contained in any applicable implementation
                                     A-27

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       Terms
               Definition
    Reference
STATIONARY
SOURCE FUEL
OR EMISSION
LIMITATION
(cont.)
plan (other than a requirement imposed pur-
suant to Section 110(a)(2)(F)(v) of the Act),
and which limits, or is designed to limit,
stationary source emissions resulting from
combustion of fuels, including a prohibition
on, or specification of, the use of any fuel
of any type, grade or pollution characteristic.
STRUCTURE,
BUILDING,
FACILITY,
INSTALLATION
Any grouping of pollutant-emitting activi- 40 CFR 51.24
ties which are located on one or more con-
tiguous or adjacent properties and which
are owned or operated by the same person
(or by persons under common control).
SUBMERGED FILL
PIPE
Any fill pipe the discharge opening of
which is entirely submerged when the
liquid level is 6 inches (15 cm) above
the bottom of the tank; or when applied
to a tank which is loaded from the side,
means any fill pipe the discharge open-
ing of which is entirely submerged when
the liquid level is 18 inches (45 cm)
above the bottom of the tank.
40 CFR 51.328
TOTAL REDUCED
SULFUR
The sum of the sulfur compounds hydrogen
sulfide, methyl meroaptan, dimethyl sul-
fide, and dimethyl disulfide, that are
released during the kraft pulping opera-
tion and measured by Reference Method 16.
40 CFR 60.283
TRANSPORTATION
CONTROL MEASUR
Any measure, such as reducing vehcile use, 40 CFR 51.1
changing traffic flow patterns, decreas-
ing emissions from individual motor vehi-
cles, or altering existing modal split
patterns that is directed toward reducing
emissions of air pollutants from transpor-
tation sources.
TRUE VAPOR
PRESSURE
The equilibrium partial pressure exerted   40 CFR 60.111
by a petroleum liquid as determined in ac-
cordance with methods described in Ameri-
can Petroleum Institute Bulletin 2517,
Evaporation Loss from Floating Roof Tanks,
1962.
                                     A-28

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       Terms

UNIVERSAL
TRANSVERSE
MERCATOR (UTM)
SYSTEM
               Definition

System designed by U.S. Army to provide
for the projection of square grid zones
with convenient measuring units.
                                               Reference
                                           APTD-1135
VAPOR RECOVERY
SYSTEM
A vapor gathering system capable of col-
lecting all hydrocarbon vapors and gases
discharged from the storage vessel and a
vapor disposal system capable of proces-
sing such hydrocarbon vapors and gases so
as to prevent their emission to the
atmosphere.
                                           40 CFR 60.111
VARIANCE
VOLATILE ORGANIC
COMPOUNDS (VOC)
                                           40 CFR 51.1 (y)
The temporary deferral of a final comp-
liance date for an individual source sub-
ject to an approved regulation, or a tem-
porary change to an approved regulation
as it applies to an individual source.
Any compound containing carbon and hydro-  40 CFR 51.328
gen or containing carbon and hydrogen in
combination with any other element which
has a vapor pressure of 1.5 pounds per
square inch absolute (77.6 mm.Hg) or
greater under actual storage conditions.
WELFARE
Referring to effects on (welfare) in-
cludes, but is not limited to, effects on
soil, water, crops, vegetation, manmade
materials, animals, wildlife, weather,
visibility, and climate, damage to and
deterioration of property, and hazards to
transportation, as well as effects on
economic values and on personal comfort
and well-being.
                                           Clean Air Act
                                           Sec. 302(h)
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VARIATION IN DEFINITIONS

     A review of state air pollution regulations was performed to determine
whether variations to the common terminology listed in Appendix A were
present.  It was apparent that many of the terms used by state air pollution
regulations were indeed the same as the Federal version.

     A few terms that were used in state regulations, but not listed in Federal
texts are presented in Appendix A.  In every set of State Regulations or Laws,
some section of the text was devoted to the definitions utilized in the parti-
culate document.

     One of the more commonly occuring differences between Federal and state
definitions is the definition of a source or a facility.  State agencies
typically refer to a facility as being comprised of one or more sources; the
latter referring to an identifiable piece of process equipment capable of
emitting one or more pollutants.  Conversely, Federal regulations define
these two terms in the opposite manner; a source is comprised of one or more
facilities.  In this case the source represents a plant, and facilities would
refer to specific emission points within the plant.  Since this and similar
discrepancies in definitions has lead to ambiguous enforcement of regulations,
the EPA now requires that all SIP's for nonattainment areas adopt Federal
definitions in order to be approved.
                                     A-30

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      Terms
AIR POLLUTANT
               Definition
    Reference
Dust, fumes, mist, smoke, vapor, odor,     District of
particulate matter, or any combination     Columbia
thereof, except that such term shall not
include uncombined water in the atmosphere
unless it presents a safety hazard.
AIR POLLUTANT
Presence in the outdoor atmosphere of one  Alaska, Alabama
or more air contaminants in quantities and
duration that tend to be injurious to human
health or welfare, animal or plant life or
property or would reasonably interfere with
the enjoyment of life or property.
AIR POLLUTION
SOURCE (PORTABLE)
Any source such as, but not limited to,    Colorado
asphalt batch plants and aggregate crush-
ers which commonly and by usual practice
are moved from one site to another.  A source
will not be considered portable if it re-
mains on one site for more than two years.
EXISTING SOURCE
Any source in operation or on which con-   Alabama
struction has commenced on the date of
initial adoption of an applicable rule,
or regulation; except that any existing
source which has undergone modification
of an applicable rule or regulation, shall
be reclassified and considered a new source.
FACILITY
Machinery, equipment, structures or any    Utah
part of accessories thereof, installed or
acquired for the primary purpose of con-
trolling or disposing of air pollution.
It does not include an air conditioner,
fan or other similar device for the com-
fort of personnel.
FACILITY
A unit or multiple units built, installed
or established to serve a particular
purpose.
Alaska
                                     A-31

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      Terms

MAJOR STATIONARY
SOURCE
               Definition

Any stationary source or modification to a
stationary source  which increases the
allowable emission rate of any air contam-
inant by an amount equal to or greater than
50 tons per year; 1000 pounds per day; or
100 pounds per hour; whichever is more
restrictive.
    Reference
POINT SOURCE
Any mobile source, process source or
stationary source which is subject to
emission rate standards or other stan-
dards imposed by these (Conn.) regulations.
Connecticut
PROCESS
Any action, operation or treatment of      District of
materials, including handling and stor-    Columbia
age thereof, which may cause discharge of
an air contaminant, or contaminants into
the atmosphere, but excluding fuel burning.
PROCESS
Any stationary emission source other than
a fuel combustion emission source or an
incinerator.
Illinois
PROCESS OPERATION
Any chemical, industrial, or manufacturing Delaware
operation including, but not limited to,
heat transfer, fluid flow, evaporation,
humidification, absorption, extraction,
distillation, drying, mixing, classifica-
tion, sedimentation, decantation, filtra-
tion, crystallization, centrifugation,
disintegration and material handling.
PROCESS SOURCE
The last operation or process which pro-   Arizona
duces an air contaminant resulting from
(i) the separation of the air contaminant
from the process material, or (ii) the
conversion of constituents of the process
material into air contaminants and which
is not an air pollution abatement operation.
                                     A-32

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      Terms
PROCESS SOURCE
               Definition

Any operation, process, or activity ex-
cept (1) the burning of fuel for indirect
heating in which the products of combus-
tion do not come in contact with the pro-
cess material, (2) the burning of refuse,
and (3) the processing of salvageable
material by burning.
    Reference
Connecticut
SOURCE OR FACILITY Any property,  source,  facility,  building,   Georgia
                   structure,  location, or installation at,
                   from,  or by reason of  which emissions of
                   air contaminants  are or may reasonably be
                   expected to be emitted into the  atmosphere.
SOURCE OPERATION
Any manufacturing process or any identi-
fiable part thereof emitting an air con-
taminant into the outdoor atmosphere
through one or more stacks or chimney.
New Jersey
                                    A-33

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                                  REFERENCES
 1.    The Clean Air Act and Amendments.

 2.    Code of Federal Regulations (CFR).   Title 40.   Parts 50, 51, 55, 60
      80, 81, 85.   .

 3.    The Environmental Reporter.  Sections 121, 125, 128.

 4.    Guide for Compiling a Comprehensive Emission Inventory, Report No.
      APTD-1135 US EPA, Office of Air and Waste Management, Office of
      Air Quality  Planning and Standards.

 5.    Compilation  of Air Pollutant Emission Factors, AP-42, and Supplements
      1-8.  US EPA, Office of Air and Waste Management, Office of Air Quality
      Planning and Standards.  April 1973.

 6.    Federal Register, 44FR J1924, September 5, 1979.

 7.    Supplementary Guidelines for Lead  Implementation Plants, EPA-450/2-78-
      038.  US EPA, Office of Air, Noise, and Radiation, Office of Air
      Quality Planning and Standards. August 1978.

 8.    AEROS Manual of Codes, EPA-450/2-76-005 (OAQPS No. 1.2-042)  US EPA,
      Offfice of Air and Waste Management.  Office of Air Quality Planning
      and Standards.   April 1976.

 9.    Interim Guideline on Air Quality Models, OAQPS No. 1.2-080.  US EPA,
      Office of Air Quality Planning and Standards.   October 1977.

10.    1974 National Emissions Report: National Emissions Data System of
      the Aerometric and Emissions Reporting System, EPA-450/2-78-026.
      US EPA, Office of Air, Noise, and  Radiation; OAQPS.  April 1978.
                                      A-34

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                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
1. REPORT NO.
   EPA-450/4-81-026a
4. TITLE AND SUBTITLE
   Procedures for Emission Inventory Preparation

   Volume  I:   Emission Inventory  Fundamentals
5. REPORT DATE
  September 1981
6. PERFORMING ORGANIZATION CODE
                                                            3. RECIPIENT'S ACCESSION NO.
7. AUTHOR(S)
   Monitoring and Data Analysis  Division
   Office  Of Air Quality Planning and Standards
                                                            8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
   U.  S.  Environmental Protection Agency
   Research Triangle Park, NC  27711
                                                            10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
                                                            13. TYPE OF REPORT AND PERIOD COVERED
                                                            14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
    EPA Project Officer:  A.  A.  MacQueen
16 ABSTRACT
         Procedures  are described for  compiling the complete  comprehensive emission
    inventory  of  the criteria pollutants  and pollutant sources.   These procedures
    described  are for use in the air quality management programs  of state and local
    air pollution control agencies.
         Basic emission inventory elements—planning, data collection, emission esti-
    mates,  inventory file formatting,  reporting and maintenance—are described.
    Prescribed methods are presented;  optional  methods are provided.  The procedures
    are presented in five (5) volumes:
         Volume I,     Emission  Inventory Fundamentals
         Volume II,     Point Sources
         Volume III,   Area Sources
         Volume IV,     Mobile Sources
         Volume V,     Bibliography
                                              b.IDENTIFIERS/OPEN ENDED TERMS
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
     Emission Inventory  Planning
     Inventory Fundamentals
     Source Inventory
     Emissions Source
     Emissions Files Formatting
|     Questionnaire
     Air Quality Management
              c. COSATI Held/Group
18 DISTRIBUTION STATEMENT
                                              19 SECURITY CLASS (Tins Report I

                                              20 SECURITY CLASS ("fhiTpage)
              21. NO. OF PAGES
                  178
              22. PRICE
EPA Form 2220 — 1 (Rev. 4 — 77)   PREVIOUS EDITION is

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