United Stales
Environment*! Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park. NC 27711
EPA-454/B-93-050
October 1993
An
&EPA
TECHNICAL PROCEDURES FOR
DEVELOPING
AP-42 EMISSION FACTORS
AND
PREPARING AP-42 SECTIONS
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EPA-454/B-93-050
TECHNICAL PROCEDURES FOR
DEVELOPING
AP-42 EMISSION FACTORS
AND
PREPARING AP-42 SECTIONS
Office Of Air Quality Planning And Standards
Office Of Air And Radiation
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
October 1993
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This report has been reviewed by the Office Of Air Quality Planning And Standards, U. S.
Environmental Protection Agency, and has been approved for publication. Any mention of trade
names or commercial products is not intended to constitute endorsement or recommendation for use.
EPA-454/B-93-050
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CONTENTS
Page
Chapter 1: Introduction 1
Chapter 2: Purpose Of AP-42 3
2.1 Estimate Of Areawide Emissions 3
2.2 Emission Estimates For A Specific Facility 4
2.3 Emissions In Relation To Ambient Air Quality 4
Chapter 3: Internal Procedures 7
3.1 Reasons And Methods For Initiating Section Preparation And Revision 7
3.2 Overview Of Section Preparation/Revision 8
3.3 Publication 9
Chapter 4: Guide To Section Preparation/Revision 11
4.1 Description Of A Typical AP-42 Section 11
4.2 Summary Of Specifications And Format Definition 12
4.3 General .e 15
4.4 Emission Data/Data Collection 16
4.5 Data Reduction 17
4.6 Data Presentation 18
4.7 General Industry Information 18
4.8 Background Files 18
4.9 Agency/External Review 20
4.10 Final Revision 20
Chapter 5: Technical Specifications And Rationale 23
5.1 Data Standards/Test Methods 23
5.2 Statistical Methods 26
5.3 Quality Ratings/Statistical Confidence 27
5.4 Units 28
5.5 Nomenclature 29
5.6 Reporting Format 30
5.7 Figures 34
5.8 Criteria/Noncriteria Pollutants 34
5.9 Controlled/Uncontrolled Emissions 35
5.10 Paniculate 36
5.11 Condensibles 36
5.12 Total Nonmethane Organic Compounds 38
5.13 Lead , 39
Appendix A: AP-42 Section Revision Procedures A-l
Appendix B: Typical AP-42 Section ^. A-2
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IV
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Chapter 1
INTRODUCTION
The document series Compilation Of Air Pollutant Emission Factors, AP-42, published since
1972 by the U. S. Environmental Protection Agency (EPA), is a compilation of emission factor
information. An emission factor relates the quantity (weight) of pollutant(s) emitted to a unit of
source(s) activity.
Supplements to the series, which is commonly called simply AP-42, are published periodically
to provide new or revised information on emission source categories. The term "emission source
category" is used to indicate a specific industry classification producing emissions. AP-42 segments
may be categorized by industry, process, product, fuel, or other common denominators. As new
information about sources and control of emissions becomes available, AP-42 will be updated by EPA
in a timely and consistent manner.
This manual describes the procedures, technical criteria and standards for developing and
reporting emission information to be published in Volume I: Stationary Point And Area Sources of
AP-42. It is a guide for both EPA personnel and the contractors who prepare AP-42 sections. There
are special requirements for Volume II: Mobile Sources, which are mentioned below.
The emission factors reported in AP-42 have many uses. They provide persons working in air
pollution control with documented, technically acceptable estimates of source emission rates.
Emission factors can be used in making:
1. Estimates of areawide emissions
2. Emission estimates for a specific facility
3. Evaluation of emissions in relation to ambient air quality.
Further description of the purpose and uses of AP-42 is given in Chapter 2.
Chapter 3 details procedures which are followed by the Emission Factor And Methodologies
Section (EFMS) of the Emission Inventory Branch (Effi), Technical Support Division (TSD), of
EPA's Office Of Air Quality Planning And Standards (OAQPS), in preparing or revising an AP-42
section. It includes reasons for initiating a review and then describes section preparation, review and
publication procedures.
Chapter 4 details the actual tasks involved in section preparation or revision: gathering and
reduction of data; writing, documentation, and review of the draft section; and incorporation of
comments into the filial section. These tasks are done by EPA and/or a contractor, after authorization
of the work by the EFMS Chief.
Chapter 5 discusses standard procedures regarding nomenclature, graphics presentation, units,
and reporting format. It also describes the technical specifications for reporting data for total organic
compounds, paniculate matter (including PM-10), lead, toxics, and other pollutants.
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Chapter 2
PURPOSE OF AP-42
An emission factor is an estimate of the rate at which a pollutant from some activity (e. g., fuel
input to a boiler or industrial production) is released into the atmosphere, divided by the level of that
activity. Realizing that persons working in air pollution control need guidance when estimating the
quantities of pollutants released to the atmosphere by different operations, EPA has compiled all
emission factor information into the single report commonly referred to as AP-42.
AP-42 presents emission factors also in the form of empirical formulas for use in estimating
emissions under the effects of specific conditions. Data used to calculate the emission factors in AP-
42 are obtained from source tests, material balance studies, and engineering estimates.
The author(s) of an AP-42 section must consider how the emission factors will be used and must
identify for the user any qualifications or limitations of the data. AP-42 factors represent the best
available information on average emissions from the subject source categories. Statistical averages
such as AP-42 emission factors seldom will specifically represent any of the individual data used to
compute the averages, and they may describe none of the specific parts of the sample population.
Still, the averages are useful for many decision-making purposes.
The three purposes of emission factors are described in the following below.
2.1 ESTIMATES OF AREA WIDE EMISSIONS
The largest use of AP-42 emission factors is in the development of criteria pollutant emission
inventories.
In compiling an inventory, emission factors are applied to numerous emission sources within a
source category. When the recommended procedures are followed, the resultant inventory of
areawide emissions is likely to be quite accurate. Because AP-42 emission factors are assumed to
represent a hypothetical "average" facility, individual plant differences tend to cancel out when
numerous like sources are considered. Where one or relatively few facilities produce a large portion
of an area's emissions, it is more important that the inventory be based on facility-specific emission
rates, whenever available, rather than on emission factors. When a certain facility is contributing
more than about 10 percent of an area's emissions, it is probably worthwhile to consider applying a
source-specific test program.
In cases where a source category either contributes either a large percentage of overall emissions
of a pollutant, or contains a relatively small number of sources, that source category (e. g., anthracite
combustion) is divided hi AP-42 into subcategories (e. g., traveling grate, etc.). Factors given for
combustion emissions from large boilers will be based on specific information about the type of boiler
and the fuel being used, because detailed information is available on just the few large facility types
which produce the most emissions from boilers (e. g., power plants). Conversely, emissions from
concrete or asphalt batching plants are produced by numerous sources and do not generally constitute
a major percentage of the emissions in an inventory. Applying an "average" factor to these sources
introduces only a small potential for error into the overall inventory.
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Emission inventories are compiled for numerous statutory reasons, as well as for simply finding
out which sources constitute the major emitters of specific pollutants. State Implementation Plan
(SIP) regulations require that emission inventories be compiled for present and future years. SIP
submissions must show reasonable further progress toward the attainment of National Ambient Air
Quality Standards (NAAQS) for criteria pollutants. To show reasonable progress toward attainment,
control agencies in nonattainment areas must estimate emissions annually.
Estimates based on emission factors are used in the SIP process to identify major emission
sources that may need more stringent regulation. These estimates are also used as a starting point for
regulation development. For example, AP-42 factors may be used to estimate a source category's
emissions for the purpose of assessing its contribution to an ambient air quality problem.
2.2 EMISSION ESTIMATES FOR A SPECIFIC FACILITY
AP-42 emission factors are sometimes used to estimate facility-specific emissions. Although
many such applications are legitimate, some (e. g., in enforcement litigation) are clearly improper.
Legitimate facility-specific uses include the following:
• Comparison with emission estimates submitted by the owner of the facility.
• Prediction of emissions from a proposed facility.
• Development of emission estimates where the cost of source testing is not justified.
• Development of emission estimate submittals when other methods are not available. Note
that AP-42 factors should not be used when reliable and representative stack test data exist
for a facility.
Because emission factors may be used in making facility-specific estimates, particularly
regarding emissions from proposed facilities, an AP-42 section should note any conditions under
which an emission factor is not reliably applicable. Such qualifications should be described in the
section text and should be clearly footnoted in the AP-42 emission factor table.
Statutory requirements for which AP-42 emission factors may be used include Prevention Of
Significant Deterioration (PSD) permit applications and Aerometric Information Retrieval System
(AIRS) submissions. It is necessary to estimate the effects of pollutants from a proposed facility
before it is built, and in many cases, AP-42 emission factors provide the best mechanism for
estimating emissions. Because most of the factors in AP-42 represent uncontrolled emissions, control
efficiencies corresponding to Reasonably Available Control Technology (RACT), Best Available
Control Technology .(BACT), Lowest Achievable Emission Rate (LAER), etc., may be applied to
emission factors when estimating facility air emissions after any controls.
23 EMISSIONS IN RELATION TO AMBIENT AIR QUALITY
The Clean Air Act requires eventual attainment of NAAQS. Pollutant emission rates can be
used with dispersion modeling to estimate ambient levels of pollutants.
In many cases, however, there is a very complicated relationship between what is emitted by a
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source and what is measured in ambient air. Numerous dispersion models are used to establish this
relationship. Models inherently assume that the model input represents actual emissions to the
atmosphere. For instance, pollutants that are emitted as vapor
because of high stack temperatures, but which condense upon reaching the air, are assumed
to have reached ambient conditions. Certain stack test methods that do not fully account for
condensibles may thus lead to incorrect predictions of ambient levels if not adjusted.
Predicting ambient concentrations is an important use of AP-42 emission factors. Dispersion
model input requirements are to be considered in the preparation of AP-42 sections. Although a
section is not designed around the specific needs of dispersion models, when changes in report format
or units can ease the use of the factor in modeling, these changes should be suggested to the Project
Officer. For example, speciation of total organic compounds (TOQ and PM-10 should be included
in the emission factor report when available, to assist in photochemical, dispersion and receptor
modeling.
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Chapters
INTERNAL PROCEDURES
The Emission Factor And Methodologies Section is responsible for all aspects of emission
factors, including the development of new factors and the periodic revision of existing ones. EFMS
directs a limited amount of source testing for development or revision of emission factors by
contractors, and it coordinates with EPA's Office Of Mobile Sources in mobile source emission factor
development. Most source testing relating directly to emission factor development or revision is
performed by TSD's Emission Measurement Branch and the Air And Energy Engineering Research
Laboratory (AEERL). The Emission Standards Division (ESD) of OAQPS also develops emissions
data through various means to support regulation development, and EIB routinely uses these data for
developing emission factors.
3.1 REASONS AND METHODS FOR INITIATING SECTION PREPARATION AND
REVISION
The functional groups now constituting EFMS/EIB previously acquired their data for use in AP-
42 entirely from other parts of the Agency, and did not themselves generate data for emission factor
development. The Clean Air Act Amendments of 1990 added greatly to the number of air pollution
sources for which emission factor development was required, and also called for the improvement of
existing factors. This increased emphasis on emission factor availability and quality contributed
extensively to the formation of EIB and also led to funding to initiate EIB's source testing program
for generating new emission factors and updating existing factors.
Given this new emphasis on expanding the coverage and quality of AP-42 emission factors, it is
important to rank emission factor needs so that the Agency's limited resources are best applied.
Assignment of priorities regarding development or revision of emission factors may be affected by the
following:
Outside requests for better source and emission factor information, or for information on a
category not already addressed by AP-42. Requests may come from other OAQPS branches, EPA
laboratories and regional offices, state agencies, trade associations, special interest groups, or private
individuals. The requests may take the form of directives, letters, oral inquiries, or comments on
published emission factors.
New information developed initially for ESD background documents involving New Source
Performance Standards, Maximum Achievable Control Technologies (MACT), and National
Emissions Standards For Hazardous Air Pollutants (NESHAP), and for reports by various EPA
laboratories.
Contractor or consultant expertise on a source category may have developed during previous
work, either for EPA or for other clients, and may be used in a low-expense update and expansion of
available AP-42 information.
In addition to these possibilities, Section 130 of the Clean Air Act Amendments emphasizes the
process through which any party may submit valid information to EFMS for emission factor
development and revision. Before initiating a factor development or revision effort, the Project
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Officer analyzes the proposed work as it relates to existing needs and priorities, to contract funding,
or to EFMS personnel availability, the likely magnitude of the effort, and other criteria. Based on his
or her analysis, priorities for AP-42 revisions are established, and recommendations are made to the
EFMS Chief.
The tasks of section preparation will be done either by Agency personnel or by a contractor,
depending on cost, time, and contractor qualifications, as the EFMS Chief directs. These tasks
include compilation or generation of data, data evaluation, and preparation of the draft section and
background document, as well as EPA review, coordination of outside review, final editing and
formatting, and publication.
3.2 OVERVIEW OF SECTION PREPARATION/REVISION
A diagram of the process of section preparation or revision is shown in Figure A-l in Appendix
A. The first task is assembly of all available data on the emission source and the pollutants it emits.
For existing emission sections, this task includes a complete review of EFMS documents on file.
Other possible data sources are:
• A literature search through EPA Library Services of all data bases currently available.
• The AP-42 reference files in EFMS.
• The Aerometric Information Retrieval System hi EPA's National Air Data Branch (NADB).
• EPA's research laboratories.
• Criteria and toxic air pollutant information in ESD.
• Control Techniques Guidelines (CTG), Available Control Techniques (ACT), and
Background Information Documents for NSPS and NESHAPS in ESD.
• Trade associations.
• EPA Regional Offices.
• State and local air pollution control agencies.
• Operating,pennit files and applications.
• Contractor expertise.
After assembly of all available data, they are reviewed, organized, and analyzed. Using the
standards given below in Sections 5.1 through 5.3, the EPA Project Officer decides whether the
collected data are sufficient to justify preparation or revision of a section. This Project Officer review
must occur even when a contractor has compiled the data.
When sufficient data to calculate the emission factor(s) have been gathered, a new or revised
section is drafted, reviewed by the EPA Project Officer and the EFMS Chief, and corrected if
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needed. The section is then distributed for further technical review. Concurrent with section
production, a background document discussing all primary references, calculations, and other
pertinent information is prepared and reviewed similarly. The background report should identify all
data, discuss their quality rating, and document all decisions on their use. Analysis and any statistical
manipulations of the data should also be clearly documented. If estimates of data accuracy or
precision can be derived, it should be clearly noted here.
Technical review comments shall be incorporated into the background document draft, which
may then be distributed for further review to selected outside groups having technical expertise in the.
subject area, such as trade associations. Following satisfactory completion of section and background
document review, the AP-42 section is ready for publication.
3.3 PUBLICATION
Publication of an AP-42 section entails editing, clearance, and final printing. The section is first
edited by a technical editor who reviews grammar, clarity, and adherence to AP-42 format. If
necessary, the section is then returned to the author with editorial comments, and any needed revision
to the section is made. This process is greatly facilitated when the author constructs the section from
the beginning according to EPA format or has made use of a technical editor throughout the process.
After editing, the section is prepared for publication in the format described in Chapter 5.
When the section is deemed acceptable for publication by the author, the EPA editor and the Project
Officer, the EFMS Chief will enter the section into the necessary OAQPS and EPA clearance
processes.
Revised sections are usually collected and held for printing in an AP-42 supplement. All
sections completed and cleared, but not yet published, are put on the CHIEF electronic bulletin board
(BB) in a portion designated as an AP-42 "Supplement".
When the finished candidate material for a new supplement has received the required clearance,
the material is sent by EPA to the Government Printing Office for printing, returning of copies to
EFMS, and stocking copies for sale. Section authors should have thoroughly reviewed these new
sections and their background documents, especially to confirm that the approved sections and their
background documents are in full accord. At this point in the process, each author shall submit
copies of the final version of his or her section(s), the background document(s), and all references to
be placed in the AP-42 files in EFMS.
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Chapter 4
GUIDE TO SECTION PREPARATION/REVISION
This chapter is a guide for the individuals who prepare or revise emission factor reports for
publication in AP-42. Such new or revised emission factor reports are continually being prepared.
Since the AP-42 document has many authors, following a standard approach to section preparation
and revision will help to make the information presented in the document more consistent, and
therefore more accessible, to the AP-42 user.
4.1 DESCRIPTION OF A TYPICAL AP-42 SECTION
The typical AP-42 section consists of the following elements:
• General process description, with flow diagram(s)
• Discussion of emissions and any controls
• Table of emission factors and/or equations for calculating emission factors
• References
Appendix B of this document presents a typical AP-42 section, and it should be consulted early
in the section process, by both the prospective author and the clerical staff who will produce the final
section.
The AP-42 user often turns first to the table to obtain the emission factors. If the tabular
information is not clear, the user may then consult the illustration or the text, and if need be, the
references.
The emission factor table should provide the user with an emission factor for a source and
should give the user all the information needed to apply the factor correctly. The user is assumed to
have an engineering or other technical background, to be somewhat familiar with the source
operations, and to need information only about any qualifications placed on the factors. The most
important part of an AP-42 section, therefore, is its emission factor table(s), which must be able to
stand alone for use by the reasonably well informed user. A principal point to keep in mind hi table
preparation is to give emission factors for as many different subcategories within the source activity
as reasonably possible.
For example, subcategorization is usually appropriate by throughput, age of facility, or control
device. When information does not exist for a particular subcategory, such needs to be stated.
Provide footnotes which explain any and all qualification of factors that might need explanation.
These notes may be as brief as a recommendation to read the text before applying a particular factor,
or as lengthy as necessary to assist with correct factor usage.
For a simple process, a flow diagram may not be necessary. When provided, it should be
designed to complement the emission factor tables. Use the same terminology in the table and the
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diagram. Emission sources not covered in the table, either because the emissions are insignificant or
because data are unavailable, should be shown on the flow diagram for the user's information.
Illustrations are preferred, instead of simple blocks in the diagram, if they do not detract from the
primary purpose of complementing the emission factor table. Source classification codes should be
clearly marked on the diagram.
The process description text explains the flow diagram and gives a very general idea of the
process. It is not intended to give a complete explanation of the industry. The description may refer
the reader to specific references where more information can be obtained, if needed.
The emission and controls portion of the text explains the information given in the emission
factor table. Factors given in the table may also be given in the text. Footnotes in this table can
refer the user to specific information in the text, if needed to explain about an emission factor and its
application.
The references to an AP-42 section can be extremely important to a user who wishes to apply an
emission factor in detail to a specific source. Although AP-42 factors do not apply to specific sources
with absolute accuracy, factors can be used with their references to develop reasonably accurate
information about an emission source. A good reference list, including a background document
containing basic information, will be quite helpful to the user. The information in any proper
reference citation will 1) identify the reference clearly, and 2) tell the reader where to obtain a copy
of it.
4.2 SUMMARY OF SPECIFICATIONS AND FORMAT DEFINITION
The specification and format topics discussed throughout this document are summarized below.
Additional explanations are found in the noted parts of this document.
Section Length
AP-42 sections are intended to be updated periodically and are therefore written in discrete
portions, or subsections. Authors should make the best possible use of the page space. "White
space" should be held to a minimum by judicious sizing and placement of figures, tables and
text.
Table Format
As stated earlier, the emission factor table must be able to stand alone. All emission points and
pollutants are contained in the same or similar tables. Any qualifications of the data are
mentioned in footnotes to the table.
References
All data used to develop the emission factors are referenced at the end of the section. It is
desirable also to include general references on the industry to supplement the general process
description. Primary data sources and references should be preferred. Primary data sources are
those containing the original data mat are being referenced. All data sources should be traced
back to their primary source. Reference format examples are given below in Chapter 5.
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EFMS Emission Factor File
This file contains the background documents for all AP-42 sections. The file contains copies of
all versions of the AP-42 sections, all references used in the sections, and documentation of all
calculations. A more extensive description of the reference file is given in Chapter 4.
Agency/Outside Review
All new or revised sections must be reviewed within the Agency and by outside organizations
before release. Several reviews may be conducted within a single reviewing group. Ultimate
responsibility for thorough section review lies with the EFMS Chief and the Project Officer. A
more detailed discussion is found in Section 4.9.
Data Standards/Test Methods
Minimum standards for useful data are given in Chapter 5. The quality of data from acceptable
tests indicates a rating for those tests on a descending scale of A to D. When AP-42 sections
are revised, all data (including old data) are subject to these minimum standards and are rated
accordingly.
Statistical Methods
If the number of A-rated source tests is sufficient, B-, C-, and D-rated tests are not to be used to
calculate an emission factor. If the number of A-rated tests is not sufficient, B-rated tests are
used. Tests rated C and D are generally not combined with A- or B- rated tests and are to be
used only if no other higher quality data are available. However, higher ranked data may be
"downgraded" and used with lower ranked data, providing that the lower rating is maintained.
Tests for each individual facility are reduced to a single value (arithmetic mean), and the
arithmetic mean of these values is the emission factor. If the data are suitable for other
statistical reduction methods, the use of such methods should be clearly footnoted hi the AP-42
section and documented in the background report. These methods are described further in
Chapter 5.
Quality Rating/Statistical Confidence
A letter rating system descending from A to E is applied to individual factors within the
section's emission factor table. Although these ratings do not represent a numerical statistical
confidence, they do give the user a general idea of the quality of the emission factor. Guidance
for the application of these ratings is given in Chapter 5.
An activity factor is a measurement of source activity. Typically, this factor is multiplied by the
emission factor to calculate the emissions from mat source. The activity factor that best relates
to emissions is used. Consideration is also given to accepted standards of measurement hi the
industry and hi enforcement regulations. More extensive guidelines on activity factors are given
in Chapter 5. - . -
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Nomenclature
Any abbreviation or chemical formula is introduced in parentheses at first mention. The use of
vague or general terms is avoided when specific terms can be used. A glossary should be
included of definitions of terms that are industry-specific, and chemical names and pollutant
classifications are standardized. Nomenclature guidelines are given in Chapter 5.
Reporting Format
While the essence of the section is contained in the emission factor table, this can be
complemented with figures, a general process description, subsections on emissions and controls,
and references. Specific format guidelines are given hi Chapter 5.
Figures
A flow diagram should relate directly to the emission factor table (i. e., specific processes
identified in the diagram should have a corresponding entry in the table). Both box and
equipment schematics may be used. Control devices are generally not shown in the flow
diagram. Additional figures or illustrations should relate directly to the flow diagram. More
extensive guidelines are given in Chapter S.
Criteria/Noncriteria Pollutants
Emission factors for criteria pollutants, toxic pollutants, global wanning gases and compounds
responsible for depletion of stratospheric ozone are to be included hi AP-42 when data allow.
More detailed information is contained hi Chapter S.
Controlled/Uncontrolled Emissions
Emission factors hi AP- 42 should represent uncontrolled emissions. Information on controls is
contained hi the text. More detailed information is contained hi Chapter 5.
Organic Emissions
Organic emission factors are reported as total organic compounds (TOQ, methane, total
nonmethane organic compounds (TNMOQ, ethane, and other volatile and semivolatile speciated
data. Other information and composition data are presented hi footnotes or hi the text.
Complete guidelines are contained hi Chapter 5.
Lead Emissions
Lead emission factors are being added to the emission factor tables as sections are prepared or
revised. Lead is reported as elemental lead, representing both front- and back-half catches of
EPA Method 12. Data on chemical compositions or weight percent of paniculate emissions are
given hi a footnote or hi the text.
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Particulate Matter Emissions
Paniculate Matter (PM) emissions should be presented as filterable PM, filterable PM-10,
condensible inorganic PM, condensible organic PM, total PM, and total PM-10.
4.3 GENERAL
This chapter presents the purposes and objectives to be met during the preparation or revision of
an AP-42 section. The three major goals are:
• Meeting the needs of the user
• Assuring conformity of the new AP-42 section with the existing document
• Documenting all work adequately.
4.3.1 User Needs
Throughout the preparation of an AP-42 section, the needs of the user are the primary
consideration. These needs include the development of emission factors that are related to source
activity level information that is normally available to the user. The author may organize the
emission factor presentation in several levels, with each level being more specific to the source. User
needs are considered in deciding whether to provide more detail on an emission factor, as well as in
decisions for format, figure presentation, and selection of units. Before beginning preparation or
revision, the author prepares a list of the uses of emission factors (e. g., preparation of permit
applications) contained in the section. As the section develops, the presentation is evaluated in regard
to these uses.
4.3.2 Document Uniformity
The individual section being prepared is only a small part of the much larger AP-42 document.
A new or revised section must physically conform to die present emission factor reports, by following
current section organization and data presentation.
4.3.3 Documentation
Material included in a new or revised section must be documented. The starting point for a
revision will be the existing section and its documentation, as discussed above. Such documentation
includes the section references and the emission factor file. If die documentation is insufficient,
unnecessary problems and errors in emission factor selection and application may occur.
Many users take the information in AP-42 as a basis for research. Such investigations are
encouraged by EPA and may result in factor improvement in the future. Researchers will need to
trace factors back to original material (i. e., primary reference material) for proper evaluation, hence
documentation of the AP-42 source data is essential for this purpose.
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4.4 EMISSION DATA/DATA COLLECTION
Many possible sources of emission data are investigated in the preparation of an AP-42 section.
4.4.1 Literature Search
A literature search for source test and background information is conducted for the emission
source category in question. This search is conducted through EPA, other library systems, or entities
such as the National Technical Information Service. If contractor effort is involved, it usually saves
money to request/conduct searches from Agency library services directly through the EPA Project
Officer.
4.4.2 AP-42 Emission Factor File
The AP-42 emission factor file is the beginning point for any section update effort and is
reviewed for any section being updated. The file contains the background document for the existing
section, as well as its references. The file also contains additional pertinent information accumulated
by various EPA personnel. The background file is maintained by EFMS and is readily accessible to
EPA engineers and to contractors.
4.4.3 Aerometric Information Retrieval System f ATRS.)
The AIRS Facility Subsystem (AFS) point source records, located at TSD's National Air Data
Branch (NADB), will yield information on various kinds of process equipment and control devices.
AFS data also may be used to identify plants where source tests have been performed, or states that
have developed emission factors on their own for a Source Classification Code (SCQ category.
Several sort and select options are available to retrieve needed information from AIRS.
4.4.4 The EPA Research Laboratories
The various EPA research laboratories may engage hi work and produce reports that contain
emission factor information. These laboratories include the Risk Reduction Engineering Laboratory
(RREL) in Cincinnati, and both the Air And Energy Engineering Research Laboratory (AEERL) and
the Atmospheric Research And Exposure Assessment Lab (AREAL) in Research Triangle Park
(RTP). Although these laboratories are generally more research oriented than OAQPS, they often
develop and report emission data that are usable in AP-42.
4.4.5 Tftforpifltjon Gathered For NSPS And NESHAP Development
The Emission Standards Division of OAQPS is responsible for developing and promulgating
regulations for stationary sources of air pollutants. In doing this, ESD produces numerous source test
reports, background information documents (BID), and other useful technical reports.
ESD reports should be reviewed for data on the industry hi question. In addition, the Industrial
Studies Branch (ISB) and the Chemicals And Petroleum Branch (CPB) of ESD maintain files of
articles on each source category for which standards are being developed. ESD's Pollutant
Assessment Branch (PAB) collects information on hazardous air pollutants. These files should be
checked for information that may be pertinent to AP-42 section development.
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4.4.6 Trade
Affected trade associations, which are usually aware of AP-42 and its uses, generally possess the
most current process information available, including successful process modifications, control
devices, etc. Whenever possible, these associations should be consulted, especially for comments on
the draft version of a section. Effi maintains a computerized list of potential and past contacts, by
section, and their phone numbers and addresses.
4.4.7 The EPA Regional Offices
The Regional Offices can be surveyed for general data and source test reports, if there are
reasons to believe such data exist. This information may be especially pertinent when a source
category under review involves a particular Region. Examples would be anthracite coal in Region
IE, sulfite paper mills in Regions I and X, and bagasse-fired boilers in Regions IV and IX.
The EFMS Project Officer will make the initial contact with a Regional Office for such data.
Initial requests should be specific. It is helpful to find Region personnel who have visited the sources
being studied and who can offer invaluable detailed information on equipment configurations, control
devices, emissions, etc., maybe not otherwise be available.
4.4.8 State And Local Control Agencies
State agencies are contacted if a source category is concentrated in the state, with initial contact
made by the EFMS Project Officer. As with the EPA Regions, it is desirable to contact someone
who has visited the source types of concern. U. S. Office Of Management And Budget (OMB)
regulations dictate that no more than nine state agencies may be contacted with the same request.
State agencies may be contacted through the respective EPA Regional Offices.
4.4.9 Contractor Expertise
Certain contractors, consultants, and teachers may have acquired expertise in past field work that
may be useful in studying a source category. This expertise can be of assistance to the author in the
preparation, revision or review of an AP-42 section.
4.4.10 Other EPA Divisions. Branches Or Sections
Other parts of the Agency, such as OAQPS's Stationary Source Compliance Division (SSCD)
and Emission Measurement Branch (EMB) of TSD, and the Office Of Research And Development
(ORD) should be contacted in seeking information on a source category.
4.5 DATA REDUCTION
Data for emission factor development are gathered from many sources and in many forms. The
quality of the data varies from precise to an educated guess. Standard methods are used hi the
reduction of these data to a single-value emission factor. The data reduction is well documented, and
the user is informed hi the section of any deviations from the procedures set forth hi Chapter 5,
Technical Specifications And Rationale.
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Chapter 5 presents minimum standards for accepting test data. Acceptable source tests are
quality rated from "A" to "D". All similarly rated tests from a facility are combined by computing
the arithmetic mean of the data.
Data with similar quality ratings but from different facilities are combined by computing the
arithmetic mean of the data. Rules for combining data with different quality ratings are detailed in
Chapter 5.
In the finished AP-42 section, a rating system descending from "A" to "E" is applied to all
factors in the emission factor table. Although this emission factor rating is influenced by the quality
of test data, it is determined by a different system from that used to rate source tests. Rules for
applying this subjective rating system are contained in Chapter 5.
4.6 DATA PRESENTATION
The most critical component of an AP-42 section is its emission factor table. The process flow
diagram correlates with the emission factor table. It may show nonemitting process operations not
listed in the table, but all emitting operations listed in the factor table must be shown hi the flow
diagram. Other illustrations are included if they relate directly to the flow diagram. The section text
addresses both the emission factor table and the process flow diagram.
The units of measurement chosen are those that best relate to emissions and that are reasonably
understandable by the user. Both metric units and English equivalents are given, with the metric unit
information always presented first, as is required by government regulations. Abbreviations or
chemical formulae may be used, but their full meaning is always indicated at first usage. Jargon is to
be avoided, unless it is fully explained.
A more extensive guide to data presentation is given in Chapter 5 of this report.
4.7 GENERAL PROCESS INFORMATION
Although supplying general source information is not the primary purpose of AP-42, such
information sometimes helps in applying emission factors correctly. The inclusion of general industry
information can familiarize the AP-42 user with the basic workings of a source category, what is
produced, the process used to produce end product, and the raw materials used in the process.
Descriptive information is usually quite brief, a page or less, unless more is needed to explain
complex processes. More detailed description of the activity should be restricted to the background
document when preparing AP-42 sections. The author should assume that the user has little prior
knowledge of the specific source category, but it should also be assumed that the reader has some
engineering or other technical background and is somewhat knowledgeable of emissions from air
pollution sources.
4.8 BACKGROUND FILES
The file containing the documentation and background for every AP-42 section is maintained by
EFMS. This file for each section contains all information on that source category obtained by the
EFMS hi the past.
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When work on a new or revised AP-42 section is completed, its author is required to furnish
EFMS the final section and all information used hi producing it. This material will then be added to
the information already supporting that section. Every section file should contain:
• A copy of the current and all previous versions of the AP-42 section, and background
documents.
• The emission factor documentation, presenting the data and calculations used to produce
the emission factors.
• A paper copy or a microfiche of all section references, unless the Project Officer agrees
that front covers with just the cited text will be sufficient to support inquiry on the
section while conserving file space.
• Any unreferenced documents, reports or articles that provide supplemental
information for the section.
• Space for new documents, reports and data to be filed for consideration in making
future revisions.
The emission factor documentation submitted by the author provides a record of the data used to
produce the factor, the sources of those data, and the actual data calculations.
The emission factor documentation is a completely adequate record of how each emission factor
was produced. Copies of the documentation will be provided to persons who call or write requesting
such information after the section is published. Specifically, the emission factor documentation
contains the following:
• A list of the primary references from which the factor data were derive, as listed in the
AP-42 section.
• A list of all collected data, with specific references to page or table numbers in the
.material in which these data were found.
• A complete record of all calculations, including units.
• A complete record of all assumptions, technical procedures, and rationale used hi
calculating or reducing the data.
The purpose of the full AP-42 file in a section is twofold: (1) to allow quick location of
supporting references when the applicability or accuracy of factors is questioned, and 2) to provide
knowledge of both the background of, and basis for, current factors when deciding
whether new data should make changes necessary.
This section file is labelled according to the section numbering system used in AP-42. The
cover of each section file should show the following information:
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Chapter and section name and number, e. g., Chapter 10, Wood Products Industry: Section
10.1, Chemical Wood Pulping.
• A numbered list of the section references contained in the folder.
• A list of commonly available references, such as EPA documents, or textbooks such as
Perry's which contain pertinent information on the source category. All references must
be primary references.
• A list of any references found elsewhere in the file (give location).
• A list of any references that are not available, such as old publications and personal
communications.
• A list of any material such as bulky test reports and contract reports that can be found
in other, clearly designated, sections of the emission factor files (e. g., special contract
section, source test report section, etc.).
All references for a section should be accounted for in one of the above categories of required
file contents. The references themselves are to be clearly identified (title, author, place of
origin,date, page, etc.) and be numbered, with the corresponding date of the AP-42 revision in which
they are used plainly included in the heading.
A section file includes as many of the referenced documents as can be obtained. For instance,
transcripts are to be made of personal and telephone communications. If only a few pages from a
lengthy work are cited, only these need to be copied and included in the file. When pertinent source
test results are summarized in a few pages, include this summary as well as the source test itself. In
copying tables, graphs and test results, the specific information that is used directly from the
reference is identified. This saves time (and may avoid ambiguity) when someone else revises the
section at a later date.
4.9 AGENCY/EXTERNAL REVIEW
After the draft section and background report are prepared, both are reviewed by the Project
Officer and the EFMS Chief for clarity, technical accuracy, and thoroughness. Others in EFMS will
likely participate in the review. Their suggestions to the author will be incorporated until the section
is approved.
•.v •
After this stage, the draft section is then sent for review outside of EFMS, as directed by the
Project Officer. In general, anyone who supplied technical data for the section is asked to review the
draft report. External reviewers should include appropriate representatives of industry, state/local
agencies, environmental organizations and other technical experts who will consent to comment.
4.10 FINAL REVISION
With the Project Officer, the author reviews all comments for incorporation into the section.
Whenever significant changes are made in response to review comments, a further draft may be
circulated for external review. All comments and recommendations are seen by the EFMS Project
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Officer, who approves any proposed revisions. The author makes approved changes before the next
submission.
Upon incorporation of the accepted changes, the Project Officer and the EFMS Chief will again
review the section and background report and then consider giving final approval. The final approved
version is then prepared and sent to the Project Officer for inclusion hi AP-42. During the review
and revision stages, the emission factor documentation should be completed for submission to EFMS
for inclusion in the section file.
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Chapters
TECHNICAL SPECIFICATIONS AND RATIONALE
Because the AP-42 document series contains many sections produced at different times by
different authors, uniform reporting and editorial practices are essential. This chapter sets forth
standards to be followed in data collection, units, nomenclature, report format, and figure
presentation. Technical guidance and rationale are provided on areas for which specifications cannot
be easily verbalized. .
5.1 DATA STANDARDS/TEST METHODS
Emission factors hi AP-42 typically are based on data obtained from several sources, including,
but not limited to, published technical papers and reports, documented emission test results, and
personal communication. The provided data may vary from single values to ranges of minimum and
maximum values, and even to data from replicated source tests. Some data sources provide complete
details about their collection and analysis procedures, while others provide relatively little information
in this regard.
It is important that each factor in AP-42 receive a quality rating, which serves as an assessment
of the confidence the author places in the accuracy of the emission factor. The first step is to rate the
test data used hi deriving the factor. In many cases, this will require review of primary sources of
numerical data (source tests or other raw data) to ensure that consistent and current criteria applied to
rate the data. This is especially true for the ratings assigned to emission factors hi Effi's Factor
Information And Retrieval System (FIRE), which may not be the same ratings as those hi AP-42.
Ratings from FIRE should not be used without first subjecting the primary sources of numerical data
to the criteria presented in this chapter. Most data hi FIRE and SPECIATE are of unknown quality
and will likely be unratable, or "E" at best (see "Quality Ratings/Statistical Confidence" below),
because of poor technical foundations (engineering estimates), small source test populations, lack of
source test documentation, etc. Where data quality precludes the assignment of ratings, the data may
be qualitatively referenced in the AP-42 section or hi tabular form, and/or the reader may be referred
to SPECIATE for additional information.
Two EPA publications may be used to assist the reviewer hi examining source test reports for
AP-42, the Guidebook: Preparation And Review Of Emission Test Reports, and the Guidebook:
Preparation And Review Of Site Specific Test Plans. These references are designed to acquaint the
reader with common protocols employed for source testing, including information on test programs,
sampling locations, Quality Assurance/Quality Control activities, sampling and analytical procedures,
and reporting and data reduction requirements. These guidebooks may be accessed through the
Emission Measurement Technical Information Center (EMTIQ electronic bulletin board (BB) or by
direct request for copies to EMTIC at (919) 541-0200.
In some cases, a review of information used to develop an existing factor will result hi a
downgrading of its rating. Example reasons for this are (1) the use of less stringent rating criteria hi
the past, (2) questionable data quality for some of the older factors, or (3) changes hi test methods.
It may be necessary to introduce other rating criteria for data quality not addressed hi this
document. This may be done if it is adequately explained hi the background report. Keep hi mind
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that the rating process is an imperfect attempt to introduce objectivity into a judgmental process, and
that professional judgment may influence some ratings.
The author should select data on the basis of the quantity and quality of data available. The
following types of data should be treated with caution before using information from such tests:
1. Test series averages reported in units that cannot be converted to the
selected reporting units (see below).
2. Test series involving incompatible test methods (i. e., comparison of the
EPA Method 5 front half with the EPA Method 5 front and back half).
3. Test series of controlled emissions for which the control device is not fully
specified.
4. Test series in which the source process is not clearly identified and
described.
5. Test series hi which it is not clear whether the emissions measured were
controlled or uncontrolled.
If there are no reasons to exclude certain test data or data sets from consideration, each data set
is assigned a quality rating of from A (best) to D (worst). Such a rating system is needed to indicate
data reliability, since some data may be used when little other information is available but the same
data would be excluded when sufficient high-quality data exist. The data are rated as follows:
A - When tests are performed with sound methodology and are reported hi enough detail
for adequate validation. These tests are not necessarily the EPA reference method
tests, although such reference methods are preferred and certainly to be used as a
guide.
B - When tests are performed by a generally sound methodology, but they lack enough
detail for adequate validation.
C - When tests are based on an untested or new methodology or are lacking a significant
amount of background data.
D - When tests are based on a generally unacceptable method, but the method may
provide an order-of-magnitude value for the source.
While this rating system provides guidelines for data/source test ratings, it is important to
recognize that it allows for discretion on the part of the reviewer. For example, if the reviewer is
examining data that are based on a generally unacceptable method (i. e., a rating of "D" as described
above), but it is known mat, hi this case, the method provides accurate values, the reviewer can
upgrade the data from a "D" rating, but the rationale for the upgrade must be indicated.
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The following criteria should be used to evaluate source test reports for sound methodology and
adequate detail:
1. Source operation. The manner in which the source was operated is well documented in
the report. The source was operating within typical parameters during the test.
2. Sampling procedures. If actual procedures deviated from standard methods, the
deviations are well documented. Procedures often must be altered in testing an
uncommon type of source. When this occurs, an evaluation is made of how such
alternative procedures could influence the test results.
3. Sampling and process data. Many variations can occur without warning during testing,
sometimes without being noticed, that can induce wide deviation in sampling results. If
a large spread between test results cannot be explained by information contained in the
test report, the data are suspect and may be given a lower rating.
i
4. Analysis and calculations. The test reports contain original raw data sheets. The
nomenclature and equations used are compared with those specified by EPA, to assure
equivalency. The depth of review of the calculations is dictated by the reviewers'
confidence in the ability and conscientiousness of the tester, which in turn is based on
factors such as consistency of results and completeness of other areas of the test report.
An "A" rated test may be a stack test, material balance, or some other methodology, provided it
is generally accepted as a sound method of measuring emissions from that source. In some cases, a
material balance calculation may be more applicable, and therefore rated higher, than a stack test.
Because just one combined value is used to calculate the AP-42 emission factor for each process,
only the results of tests of equal quality ratings are retained when multiple-series tests are run at the
same process. However, higher rated test data may be averaged with lower rated data, provided the
overall emission factor rating is adjusted to reflect the use of lower rated data.
Although the test rating system described above is subjective, it provides a basis for excluding
poor data when a sufficient quantity of better data is available. The compiler must attempt to
ascertain how representative the tested facility is of the entire industry. For example, source tests
performed for the preparation of New Source Performance Standards (NSPS) are generally conducted
at well designed and well operated facilities that are not always typical of an industry. If a substantial
portion of the data used in deriving an emission factor comes from NSPS tests, this fact is footnoted
hi the emission factor table.
When an existing AP-42 section is revised, the quality standards must be applied to the data used
to calculate the current factor. Because some valid data may have been excluded in the past because
of poor documentation, all new data must be clearly documented, and the reasons for assigning the
rating clearly stated, hi the background information. When data rated lower than B are used in
calculating an emission factor, the table is footnoted to explain any limitations the emission factor
may have. An example of this may be found in the sample AP-42 section in Appendix B.
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5.2 STATISTICAL METHODS
AP-42 emission factors are based on data from published and unpublished reports, technical
papers, and personal communications among individual investigators. Emission data extracted from
source documents may have been determined by emission source testing, material balance, or
engineering analysis.
Thus the emission factors represent statistical averages derived from a sample of emission
sources, or single values determined through engineering judgment to be representative of the data
available on a specific source category.
In the ideal situation, a large number of "A" rated source test sets representing a cross section of
the industry are reduced to a single value for each individual source by computing the arithmetic
mean of each test set. The emission factor is then computed by calculating the arithmetic mean of the
individual source values. No "B", "C", or "D" rated test sets are used in the calculation of the
emission factor, because the number of "A" rated tests is sufficient. This ideal method of calculating
an emission factor is not always possible, usually because of a shortage of "A" rated data.
The number of "A" rated tests needed to represent a cross-section will vary among source
categories. Several variables influence this number:
• The total number of facilities in the nation (sample size vs. total population).
• The variability of emissions within the industry.
• The variability of emissions from within each facility.
• The representativeness of the sample in the total industry
Because rating judgments can be subjective, the rationale behind a decision is to be documented
in the background information. If possible, estimates of these variables are made. At a minimum,
the author attempts to estimate the total number of facilities in the nation.
Specific information hi the background document should include, but not be limited to, the
following:
• Number of facilities tested.
• Estimate of number of facilities in the United States.
• Range of emissions nationwide (minimum to maximum).
• Range of emissions for each facility tested (minimum to nigximpm, arid number of tests).
• A description of how the sample was chosen (i. e., random, NSPS tests, etc.) and whether
this may cause bias in the data.
If the number of "A" rated tests is such that the inclusion of "B" rated tests would likely
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improve the emission factor, then "B" rated test data are included in the compilation of the arithmetic
mean. However, no "C" or "D" rated test data may be averaged with "A" or "B" rated data. The
rationale for using any "B" test data is always documented in the background information. As more
"A" rated.data become available, the "B" test data must be dropped from the emission factor
calculation. A footnote to the emission factor table should inform the user of any limitations on
applying the emission factor.
If no "A" or "B" rated test results are available, the emission factor is the arithmetic mean of the
"C" and "D" rated test data. When "C" and "D" test data are used, any limitations on the use of the
emission factor are clearly footnoted in the emission factor table. "C" and "D" rated data are used
only when sufficient "A" and "B" data are not available,
and provide only an order-of-magnitude value.
Throughout the statistical process, test results from an individual source are reduced to a single
value by using the arithmetic mean, and individual source emission factors are combined by
computing the arithmetic mean. In some industries where the median may be more representative of
a typical value, the more appropriate statistical method (mean or median) is used. The rationale for
its use is documented in the background information. An explanatory footnote should be added to the
emission factor table, lest a user could conclude that the emission factor represents an arithmetic
mean.
The author should attempt to reduce the data to a single emission factor, rather than to a range
of values. However, if a range of values can be categorized, the author may present several emission
factors related to facility variables (e. g., age, throughput, fuel), or even formulae for that purpose.
5.3 QUALITY RATING/STATISTICAL CONFIDENCE
In an AP-42 section, a table of emission factors is presented for each pollutant emitted from each
of the emission points associated with a polluting activity. The reliability of each factor is clearly
indicated in the table by an Emission Factor Rating ranging from "A" (excellent) to "E" (poor).
These ratings take into account the quality and quantity of data from which the factors were
calculated.
The use of a statistical confidence interval may seem desirable as a more quantitative measure of
the reliability of an emission factor. However, because of the way an emission factor data base is
generated, prudent application of statistical procedures precludes the use of confidence intervals,
unless the following conditions are met:
• The sample of sources from which the emission factor was determined is representative of the
total population of such sources.
• The data collected at an individual source are representative of that source (i. e., temporal
variability resulting from typical source operating conditions may bias the data).
• The measurement method was properly applied at each source tested.
Because of the extremely difficult task of assigning a meaningful confidence limit to the above
variables and to other industry-specific variables (e. g., differences in determining fuel
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characteristics), using a statistical confidence interval for an emission factor is not usually practical.
Therefore, some subjectivity in a quality rating is necessary. The following emission factor ratings
are applied to the emission factor table. Note that the following descriptions are suggested guidance,
and that not all data combinations for each rating are addressed.
A - Excellent. Developed only from "A" rated source test data taken from many randomly
chosen facilities in the industry population. The source category is specific enough to minimize
variability within the source population.
B - Above average. Developed only from "A" test data from a reasonable number of facilities.
Although no specific bias is evident, it is not clear if the facilities tested are a representative
sample of the industries. As with the "A" rating, the tested source is specific enough to
minimize variability within the source population.
C - Average. Developed from only "A" and "B" rated test data from a reasonable number of
facilities. Although no specific bias is evident, it is not clear if the facilities tested represent a
random sample of the industry. As with the "A" rating, the source category is specific enough
to minimize variability within the source population.
D - Below average. Developed from only "A" and "B" test data from a small number of
facilities, with a reason to suspect that these facilities do not represent a random sample of the
industry. There also may be evidence of variability within the source population. Any
limitations on use of the emission factor are footnoted hi the factor table.
E - Poor. Developed from "C" and/or "D" rated test data, with a reason to suspect that the
facUities tested do not represent a random sample of the industry. There may also be evidence
of variability within the source category population. Any limitations on the use of these factors
are always clearly noted.
Because the assignment of these ratings is subjective, the reasons for each rating are documented
in the background information. Calculation of individual confidence limits is encouraged for all
variables associated with a factor in assigning the "A" to "E" ratings. Stringent adherence to these
criteria should be coupled with knowledge and experience with the industry, and the rater should
apply good engineering judgement to the assignment of ratings and to whether any quantitative .
statistics would be meaningful. Documentation for this determination is to be presented in the
background information.
5.4 UNITS
An emission factor is an estimate of the rate at which a pollutant is released to the atmosphere
because of some activity, divided by the level of that activity (activity factor). The units chosen for
an activity factor depend on the data available to the person preparing the emission factor and on the
data available to the AP-42 user. The activity factor is chosen according to how the industry in
question tabulates production data and on how emission tests were performed. Units may be as
varied as "megagrams of solvent in ink", "tons of wood treated", "surface area of storage pile" and
"bales of cotton ginned". When both input and output rates are readily available from the industry,
the rate that best correlates to emissions and is most likely to be familiar to the user should be
selected.
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With a few exceptions, values throughout AP-42 are presented in both metric and English units.
As stated earlier, metric units are given preference in AP-42. The U. S. Government encourages the
use of the modern metric system (the International System Of Units, better known as SI units) in all
federal documents and activities.
These guidelines are to be followed when choosing an activity factor.
1 . Use the one that best relates to the pollutant emitted
2. Give preference to accepted standards of measurement to which the user is likely to have
easy access
3. Give consideration to units specified in enforcement regulations.
When an appropriate activity factor has been decided upon, the author obtains the approval of it
from the Project Officer. Sometimes it may be desirable to have more than one set of equivalent
units.
In certain industries, the most appropriate activity factor or factors for more source-specific
breakdowns may not be available to all users. In these cases, an activity factor is given for the
overall facility, and source-specific information is included when available. One of the dual factors is
to be labeled "preferred" to avoid confusion or double counting.
As noted, metric units are used before equivalent English units, in both text and tables. In
special cases, the author, with the Project Officer's agreement, may choose units that are not strictly
metric or English, but which the user will be more familiar with, for example, "grams per mile
(g/mi)" for mobile source emissions. A unit no longer accepted is the metric ton (MT), because the
equivalent megagram (Mg) is a standard unit. The metric units to be used are those set forth in the
Standard Practice For Use Of The International System Of Units (Modernized), American Society For
Testing And Materials, Philadelphia, PA, 1992.
5.5 NOMENCLATURE
"Nomenclature" is the set of terms and symbols used throughout AP-42. Industries and
organizations often support a vocabulary of terms, a jargon, that is unique and specific to itself, or
some industries may share common terminology. Any such terms used in AP-42 must be clearly
defined.
Terms and symbols used imprecisely will confuse the reader. The following nomenclature
guidelines are to be used in AP-42 to minimize this confusion.
1. Introduce each abbreviation or chemical formula in parentheses after it is first mentioned,
e. g., "... sulfur dioxide (SO^". Thereafter, use the abbreviation or formula freely.
2. Avoid the use of vague or general terms where specific terms or qualifying
adjectives would improve clarity.
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3. If needed, include a glossary at the end of section text before the references.
Give simple but precise definitions of terms that are part of the jargon or special
vocabulary of a process being described, or of common terms that have specific
meanings in that context. Do not use any jargon without first giving its
equivalent technical term or a definition.
4. Use standard names of chemicals that appear hi the emission factor tables and
cite CAS numbers.
5. Include any legal definitions necessary to the proper use of the factor in an
emission inventory.
6. SCCs should be clearly labeled on process charts and figures and may be included in the
text.
5.6 REPORTING FORMAT
The format of sections in AP-42's Volume I: Stationary Point And Area Sources is common and
consistent, such that each section of the parent volume can be easily updated, published, and
distributed as new data become available. An example of a typical AP-42 section is given in
Appendix B, and it should be followed by both the author of any new section production and the
clerical personnel rendering the work into final form.
As mentioned, the general organization of each AP-42 section is as follows:
• General description of the process
• Discussion of emissions (and if applicable, typical control devices)
• Emission factor tabulations
• List of references
The emission factor table(s), usually presented toward the end of the emission discussion portion
of the section, will be the most critical component of the document and should essentially stand alone
in terms of clear technical content. The section text, illustrations and flow diagrams explain and
qualify the tabulated emission factor data. Within the standard format, some complex source category
sections will contain general process information which is then divided into discrete subsections to
provide the necessary detail to the user. Consult Section 5.13 of AP-42, "Plastics", as an example
with numerous "subsections".
EPA has no single, authorized, definitive guidance on publication format, grammar, punctuation,
rhetorical style, or editorial policy. The long-running AP-42 format to be used in figures, tables and
references is exemplified by the "typical" section hi Appendix B of this document. Whenever the
complexity or special character of a section raises format questions not depicted hi mat example
section, the author should consult with the EPA Project Officer for direction.
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The following format guidelines are to be applied:
1. Prepare and submit the draft section on 8-1/2 x 11 inch paper as it would look in final
form, except in space-and-a-half. The draft section should also be submitted on 3.5" disc
in the latest version of the Word Perfect* program. The final version of the section shall
be submitted in these same two media.
2. Text, tables and figures must fit on 8-1/2 x 11 inch paper with 1" margins. Both may be
placed on the page in a vertical, or "landscape" position. See "Figures" below for more
information. Examples of tables and figures may be found in Appendix B.
3. Figures must complement the emission factor tables. The text complements the figures and
tables. The "Emissions" part of a section fully explains the emission factor tables. The
"Process Description" portion fully explains the flow diagram. Figures may be submitted
in a separate electronic file having a format compatible with Word Perfect software.
4. All references used must be primary references (the original source of the data), and must
be cited in a numbered list, hi the order in which they are invoked hi the text, as the last
part of each section.
5. Citing a specific reference in section text should be by superscript arabic number placed at
the end of the last pertinent sentence of that text. If referenced material is not discrete in
the text, citations may be placed by the heading of that portion of the text. For obvious
reasons, keep all citations away from formulae or other uses of number(s).
In general, tabular data should be presented by pollutant rather than by source. In complex
cases, as with necessary additional information included in the tables (such as speciated data), it may
be difficult to present emission factors for all pollutants in one table. Therefore, if needed, pollutants
should be grouped hi tables as follows:
• NOX, SOX, and CO
• PMandPM-10
• TOC
Speciated compounds for TOC, PM and PM-10 should be shown as subcategories hi the
appropriate emission factor tables. Lead emission factors should be included as speciated components
of PM and PM-10. A table for inorganic gases should be provided also, as appropriate. Speciated
compounds listed under Title m of the Clean Ah- Act (i. e., Hazardous Ah- Pollutants) should be
footnoted.
Factor references should be footnoted hi the tables. Where multiple data sources were used to
develop emission factors, it may be appropriate also to refer the reader to background reports. Every
emission factor hi the table(s) must have its rating clearly indicated. Separate tables should be
presented for metric and English units, unless there are so few factors hi a table that both measures
can be clearly presented (see Appendix B).
31
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Tabulation is not required if there are no data for a pollutant from a source, but if it is suspected
that there are significant emissions of this pollutant, a footnote would be useful, to advise the reader
and to foster development of data for future updates.
Tables of speciated organic compounds should include all compounds and not be limited to
either the hazardous air pollutant list of 189 compounds in Title m of the Clean Air Act or to other
compounds that EPA has targeted for analysis under its enhanced ozone ambient air monitoring
program. Compounds that EPA has exempted from the definition of VOC should also be included
(methane; ethane; 1,1,1 trichloroethane; methylene chloride; and chlorofluorocarbons). Any
compounds listed in Tide m should be demarked with a footnote.
The inclusion of compounds in FIRE and SPECIATE does not constitute providing AP-42
emission factors, but is more of an indicator that emissions of these compounds exist and should be
examined as candidates for rated emission factor development.
Separate tables should not be provided for stratospheric ozone-depleting and global wanning
gases. Methane and CFCs should be included hi the speciated TOC table. In general, CO2 should be
footnoted hi the CO table, and N2O footnoted in the NOX table. Where CO2 and N2O are process
related, it may be more appropriate to include headings and emission factors for these compounds in
the tables.
Text references have two important functions, to credit the source of the information and to
guide interested users to more information on the subject. One common referencing error is the
failure to supply sufficient information to tell the user specifically and clearly how to obtain a copy of
the referenced material. Another error is the failure to cite the primary source of material, citing a
source that obtained the information from some other source instead (i. e., citing a secondary or
tertiary source). References that are consistently clear and direct are of the most use to readers and
researchers.
Telephone conversations are generally not cited as references. If used, a signed written record
of the conversation is placed in the background file.
The following are selected examples of the reference format used in AP-42.
Legislation:
The Rehabilitation Act Of 1973, §504, 29 U.S.C. 794.
Federal Register Notice (Vol. 36, p. 6934):
Federal Certification Test Results For 1971 Model Year, 36 FR 6934, April 10, 1971.
Code Of Federal Regulations Notice (Title 40, Part 60, Subpart N):
"Standards Of Performance For Iron And Steel Plants", 40 CFR 60.N.
EPA publications (with an EPA document number):
J. S. Mosby and R. R. Bridgers, Source Assessment: Cattle Feedlots, EPA-007/7-77-777,
U. S. Environmental Protection Agency, Research Triangle Park, NC, June 1977.
32
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OIK of a bound collection of papers:
D. C. Current, "Commercial Bakeries As A Major Source Of Reactive Volatile Organic Gases",
Emission Inventory/Factor Workshop: Volume I, EPA-450/3-78-042a, U. S. Environmental
Protection Agency, Research triangle Park, NC, August 1978.
With contract number only (if no EPA Number is assigned):
Paniculate And Lead Emission Measurements From Lead Oxide Plants, EPA Contract No.
68-02-9999, Bimbo Research Corp., Youpon, OH, August 1973.
Source test:
Source Testing Of A Waste Heat Boiler, EPA-75-CBK-3, U. S. Environmental Protection Agency,
Research Triangle Park, NC, January 1975.
With three or more authors:
Emma Thompson, et al., Trace Emissions From The Ingestion Of Metallic Ores,
EPA-450/W-93-900, U. S. Environmental Protection Agency, Research Triangle Park, NC, October
1993.
Unnumbered:
S. Wyatt, et al., Preferred Standards Path Analysis On Lead Emissions From Stationary Sources,
Office Of Air Quality Planning And Standards, U.S. Environmental Protection Agency, Research
Triangle Park, NC, September 1974.
Periodical:
D. G. T. Beauregard, et al., "Concentration And Size Of Trace Metal Emissions From A Power
Plant, A Steel Plant, And A'Cotton Gin", Environmental Science And Technology, P(7):643-67, July
1975.
Paper:
James B. Gordon, "Characterization Of Hardball Smelter Dust", Presented at the 69th Annual
Meeting of the Air Pollution Control Association, Portland, OR, June 1976.
Book:
L. Sullivan Agnew, et al., Flow Of Information In Visionary Heavy Metal, Volume I:
Notwithstanding The Rumor, Purdue University, West Lafayette, IN, June 1973.
Privately published report:
Final Report Of The API Task Force On Used Oil Disposal, American Petroleum Institute
Committee On Air And Water Conservation, New York, NY, May 1970.
Privileged information:
Confidential test data, Bozo Contractors, Inc., Caries, NC, December 10, 1941.
Personal or official conversation:
Written (or Telephone) communication from (or between or among) Michael Hamlin, U. S.
Environmental Protection Agency, Research Triangle Park, NC, to (or and) Joan de la Chaumette,
Bureau Of Mines, U. S. Department-OfThfr Interior, Washington, DC, January 15, 1993.
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5.7 FIGURES
Figures in AP-42 sections include process flow diagrams, nomograms and graphs, and
equipment illustrations. Their principal functions are to augment the presentation of emission factors
and to provide a view of the processes as typically encountered. The extent of graphics use depends
entirely on the complexity of processes discussed.
AP-42 flow illustrations are to assist the user in the proper application of the emission factors.
Any figure that can assist a user in applying these factors is important. .The author should assume
that the user is not thoroughly familiar with the industry in question, but that she/he does have an
engineering or other technical background and is somewhat knowledgeable of emissions from air
pollution sources.
For a simple or well known process, a clearly written description may be sufficient. If the
process is complicated or obscure, a process flow diagram is necessary to assist in the understanding
of the process. If similar processes have different emission rates, an illustration is needed clearly
distinguishing the processes.
The following guidelines are to be applied in designing process flow diagrams:
1. The flow diagram relates directly to the emission factor table. The terminology
is identical, and all emission points listed hi the emission factor table are shown
in the flow diagram. SCCs should be shown on the Table.
2. Box or equipment flow schematics, or both, are used.
3. When an equipment schematic is needed which can not be presented with
sufficient detail within the overall flow diagram, a separate more detailed figure
is included, with a reference to the flow diagram.
4. In general, controls are not specified on the flow diagram. The location of
possible controls and manner of release (e. g., fugitive) are indicated, however.
5. Inclusion of a process flow diagram or other illustrations is decided by whether
the information is necessary to a proper application of the emission factors.
6. All information on the figures is designed to be clearly legible in final
reproduction.
An example process flow diagram is shown in the representative AP-42 section in Appendix B.
AP-42's format has been used over the years because it best enables the user to apply the emission
factors given in the table.
5.8 CRITERIA/NONCRITERIA POLLUTANTS
Criteria pollutants are ozone (O3) (formed from organic compound emissions), nitrogen oxides
(NOX), sulfur dioxide (862), carbon monoxide (CO), lead (Pb) and participate matter of 10 microns .
"diameter or less (PM-10). These pollutants, hi the judgment of the Environmental Protection Agency,
34
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and as designated by Congress, may reasonably be expected to endanger public health or welfare.
Through the regulatory process, EPA establishes standards for concentrations of these pollutants in
ambient air. The individual states are responsible for achieving and maintaining these standards
through EPA-approved State Implementation Plans (SIP). The author of an AP-42 section provides
emission factors for all criteria pollutants emitted by the subject source process(es). To accomplish
this goal, the author ascertains what pollutants are emitted by a source and whether data exist to
quantify them. If more specific information on criteria pollutants (such as particle size for PM-10, or
chemical composition for TOC) will help the user, this information may also be included in the text.
Through the 1990 Amendments to the Clean Air Act, Congress also designated a total of 189
compounds as hazardous air pollutants (also referred to as noncriteria pollutants). These and other
compounds will be included in AP-42 in the future, as data allow, (1) to assist in the development and
implementation of standards for hazardous air pollutant emissions and (2) to assist agencies wanting to
inventory hazardous air pollutants to assess human health risks from exposure to such pollutants.
Speciation of all compounds of organics and paniculate matter is desirable, when possible, to provide
information useable by photochemical, dispersion and receptor modelers.
5.9 CONTROLLED/UNCONTROLLED EMISSIONS
Controlled emissions are nonfugitive pollutants that are emitted after passing through an
emission control device. Uncontrolled emissions are emissions that occur beyond the point of either
product recovery or process-enriching controls. These emissions are either directed to a pollution
control device or emitted directly to the atmosphere as fugitive or stack discharged uncontrolled
emissions. When information on typical control efficiencies is given in the text of a section, a range
is preferred over a specific number.
If a control device is common to an entire industry and is considered an integral part of a
process or system, it is not appropriate to label emissions from such a device as controlled, e. g.,
chillers added to solvent operations for vapor recovery or cyclones used to recover catalyst in
petroleum catalytic cracker systems. The primary purpose of the equipment determines whether it is
considered a control device or part of the process equipment.
Emission factors listed in AP-42 should normally represent uncontrolled emissions. Any
emission factors previously listed as controlled will be converted to uncontrolled factors, whenever
possible. If such a conversion would be based on poor data, however, the current factor may be
retained, if clearly labeled as controlled. It is desirable to present both controlled and uncontrolled
factors when data warrant.
The section text contains information on controls, and where appropriate, Control Techniques
Guidelines (CTG) or other documents are referenced. The text also notes the probability of rapid
developments in control technology and the likelihood that any typical control efficiencies mentioned
will change. Where applicable, emission factors are based upon data from sources subject to NSPS.
When a control device reduces emissions of another pollutant besides the one for which it was
designed, this is known as secondary or coincidental control. For example, electrostatic precipitators
(ESP) have been known to reduce SOX and lead emissions as well as paniculate emissions. Such
secondary control effects may be less efficient than the primary control, but they are nevertheless real
and measurable. Secondary control emission reductions are to be noted in the text.
35
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5.10 PAR1TCULATE
The ambient air quality standard for paniculate matter has been revised from simply "total
suspended paniculate" to deal with paniculate matter having a mean aerodynamic diameter of 10
micrometers or less (PM-10). Although the ambient air quality standard has changed, many federal,
state and local regulations for paniculate-emitting sources continue to refer to all paniculate matter
without regard to particle size. While large diameter particle emissions may not constitute a
significant public health concern, uncontrolled emissions of such paniculate would pose public welfare
concerns such as soiling of automobiles, clothes, etc. In addition, paniculate control devices, while
most effective in dealing with large diameter panicles, do achieve a lesser but still significant
reduction of paniculate emissions in the PM-10 range. It is desirable, therefore, to retain.existing
controls on total paniculate while also applying a PM-10 standard necessary to protect public health.
Accordingly, a need exists for estimating total paniculate emissions as well as the emission of
panicles with diameters of 10 micrometers or less.
5.11 CONDENSIBLES
Condensibles are materials that are emitted as vapor and that later condense to form
homogeneous and/or heterogeneous aerosol particles. Condensation depends on three key
physicochemical variables: temperature, concentration and equilibrium vapor pressure.
Meteorological conditions in the atmosphere dictate the ambient formation rate of condensed particles.
Condensible materials may (1) readily condense to paniculate form, (2) condense, then reevaporate, •
or (3) remain indefinitely in the atmosphere in the vapor state.
Condensible paniculate may be organic, inorganic or both. It often contains sulfates, poly cyclic
organic matter (POM), or heavy metals such as lead, cadmium or arsenic. Condensed materials, as
measured by ambient sampling methods, are more likely to be found at smaller sizes (^2 microns).
In EPA Method 5, emissions are collected in two fractions, known as the front-half and
back-half catches, indicating the pan of the Method 5 sampling train in which the paniculate is
collected. Similar fractions are collected using EPA Method 17 for determining the total suspended
paniculate at stack conditions, and EPA Methods 201 and 201A for determining PM-10 emissions.
These two fractions are often referred to as the filterable and condensible fractions. This
attempt at distinction is misleading. Filterable panicles are those trapped by the glass fiber filter in
the front half of the sampling train. Particles of about 0.3 micrometers or larger are included in the
filterable paniculate catch. Also included are materials that condense to solid or liquid form at or
above the front-half filtration temperature for Method 5 (120 ± 14°C; 248 ± 25°F). Smaller
panicles and vapors (especially water) pass through the filter to a series of cold water impingers in
the back half of the train.
Materials that are found in the back-half catch include water and condensed forms of organics,
metals and other chemicals. These materials, like water, pass through the front half of the sampling
train as vapors, but condense hi the back half where a temperature of near 0°C is maintained hi the
cold water impingers. The impinger water containing the condensible catch may be analyzed using
Method 202 to determine the condensible paniculate emissions. The organic fraction is extracted with
methylene chloride, and the inorganic fraction remains hi the impinger water. The two fractions are
weighed after evaporation and desiccation.
36
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Because condensed material is removed in both the front- and back-half catches of Method 5, the
use of the terms "filterable" and "condensible" to describe the two catches is not accurate. Source
test evidence, however, suggests that the larger portion of emitted condensed material (by weight) is
in the back-half catch. Method 202 includes recommended procedures which counteract possible
chemical changes and interferences that may occur when determining condensible particulate
emissions from sources emitting SO2 and/or ammonia. The back-half collection conditions and
analysis procedures of other test methods may cause some chemical or physical changes that would
not occur upon reaching standard conditions in the atmosphere and may then result in inaccurate
information on the emissions of condensible particulate. Filterable particulate emissions, as measured
by the front-half catch of Methods 5, 17, 201 and 201 A, are normally controlled at the source by
systems that operate at temperatures well above ambient levels. This temperature level is necessary to
keep water and other materials in a source stream from condensing inside the control device and
fouling the operation. Filterable particulate can be controlled efficiently (95 percent or more) by
cyclones, ESPs, fabric filters and wet scrubbers. The first three systems would have relatively little
effect on condensible particulate, because they are generally operated at temperatures above 135°C
(275°F), the upper limit of the front-half of Method 5. Most condensible material would remain
vaporized and pass through the control device. Wet scrubbers, however, reduce the gas stream
temperature to below 94° C (200°F) and thus could theoretically remove some of the condensible
material.
Through new source testing, EPA and others have found that most industries emit condensible
particulate, in amounts that depend primarily on the specific industry, on operating conditions at
individual sites, and on the trace-element content of the feed stock. Under some conditions, the
contribution of condensed vapors to total mass emissions can be significant. For example,
calculations show that condensed sulfates constitute one third of the total mass emitted from a boiler
burning coal with a ten percent ash content and a one percent sulfur content, through a control system
with a particulate removal efficiency of 99 percent. In other processes (e. g., smelters), the fraction
of total mass emitted from the stack as hot vapors that later condense at cooler ambient temperatures
far exceeds the fraction exiting in solid form.
Because Method 202 has been developed only recently, and "back-half catch" may mean
different things to different industries, the terms "filterable" and "condensible" are to be used with
great care in AP-42 in referring to EPA Method 5 front-half and back-half catches. The following
guidelines are to be applied when presenting emission factors for total particulate mass emissions:
1. When presenting particulate emission factors, report the front-half catch as
filterable particulate.
2. Back-half catches are to be reported as both organic condensible particulate and
the inorganic condensible particulate.
3. Care should be taken when combining different test methods (filterable
particulate, organic condensible particulate, or inorganic condensible particulate)
to calculate an emission factor.
4. Particulate sizing information is to be reported, where data allow, on the
filterable particulate. _ -
37
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5. Emission control efficiencies are to be reported by particle size on the filterable
paniculate and the organic and inorganic portions of the condensible participate.
6. PM-10 emissions factors are to be reported as the sum of the in-stack-filterable
portion of the paniculate, as well as the organic and inorganic condensible
portion.
7. Calculate emission factors for lead as outlined below in Section 5.13, "Lead".
When presenting emission factors for PM-10, an alternative approach is employed. Recognizing
that considerable in-stack PM-10 emissions exist in volatilized form which will eventually contribute
to atmospheric paniculate, PM-10 emission factors are to be presented as the sum of both the instack
filterable and the condensible portion of the paniculate. This is counter to historical reporting of
emission factors for die total mass of paniculate, which excluded the back half.
5.12 TOTAL NONMETHANE ORGANIC COMPOUNDS
Volatile organic compounds have been defined according to the Federal Register (57 FR 3945)
as any organic compounds, not including carbon monoxide, carbon dioxide, carbonic acid, metallic
carbides or carbonates, and ammonium carbonate, which participate hi atmospheric chemical
reactions. A number of compounds have been deemed to be of "negligible photochemical reactivity"
and also are exempt from die definition of VOC: methane, ethane, methyl chloroform, methylene
chloride, and most chlorinated-fluorinated compounds (commonly referred to as chlorofluorocarbons,
or CFCs). Although the low photochemical reactivity rates of these compounds render them
"exempt" from most ozone control programs, they are of concern when developing the complete
emission inventories necessary hi designing effective ozone control strategies. Therefore, the
following criteria are to be applied for reporting volatile organic compound emissions in AP-42:
1. The term "Total Organic Compounds" (TOQ includes ajl VOC compounds, that is to say
"exempt" compounds, including methane and ethane, toxic compounds, aldehydes,
perchloroernylene, semivolatiles (as measured by EPA reference methods), etc.
2. The emission factor table should discreetly report die quantity of methane, ethane and other
organic species emitted by a source, whenever such information exists hi referenced
documents, and when the quality of data is sufficient to assign an emission factor quality
rating. Where die data quality is insufficient to permit an A to E rating, die reader is
referred to FIRE and/or SPECIATE for additional information. It may be acceptable in AP-
42 to present speciated data that do not meet the requirements for assigning quality ratings
but that do appear hi a credible reference. Such data must be properly footnoted to advise
the reader of data quality limitations and to indicate that its use as a factor is "speculative".
3. The value used with all compounds should be the actual weight of the emitted substance. It
is not acceptable to report the equivalent carbon of the compounds with the expressions "as
methane", "as hexane", "as propane", etc., unless no other data exist. If the author
chooses to give factors with the expressions "as methane", etc., he or she must describe the
limitations of the factors.
38
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4. Test method anomalies which result in improper characterization of compounds known to
be present shall be properly footnoted. One example is the inability of Reference Method
25 to detect formaldehyde and to be acceptably sensitive to other aldehydes. In such
instances, where aldehyde data are available from acceptable tests, total VOC should
include the aldehydes.
5. All AP-42 factors for volatile organic compounds will conform to these standards, and
background documentation prepared for AP-42 files will show that the factors do conform.
The format for presenting VOC emission factors in AP-42 tables should include the headings
shown below, when data allow, and any deviations or clarifications should be footnoted. A heading
for Total Nonmethane Organic Compounds (TNMOQ is included because most existing data are in
this form. Factors shall be expressed as mass of emissions/mass of output. The recommended VOC
headings are:
TOC METHANE TNMOC ETHANE OTHER VOLATILE
AND SEMIVOLATILE
SPECIATED DATA
5.13 LEAD
/
Lead emissions can result from combustion furnace operations, smelting processes, mechanical
processing operations, fugitive dust sources, and the use of leaded gasoline. Other sources include
the combustion of waste oil, coal and fuel oil, and the incineration of municipal wastes. Industrial
processes emitting lead include primary and secondary ferrous and nonferrous metals and alloys, lead
oxides, lead acid batteries, cable coverings, can soldering cement, printing type metals, metallic lead
products, and leaded glass.
The most common chemical forms of lead emissions from all sources are elemental lead (Pb) or
lead oxides (PbO, PbO2, Pb2O3, etc.). Other forms emitted include lead sulfide (PbS), lead sulfate
(PbSO^), lead halide paniculate (alpha and beta forms), and organic alkyl lead vapors (tetraethyl lead
and tetramethyl lead).
Lead may be emitted as a dust having particle diameters ranging from less than one micron to
ISO microns. Lead is also emitted in fumes, mists and vapors. Particle sizes of 10 microns or less in
diameter are generally considered to be inhalable and therefore quite hazardous to health.
Most gasoline sold in the United States does not contain lead, however, any leaded gasoline that
is used may contain a maximum of 0.1 grams of lead per gallon, about 75 percent of which is emitted
to the atmosphere through the exhaust. The rest is deposited in the exhaust system or in the
crankcase oil. Lead in crankcase oil may eventually be emitted to the atmosphere, if the waste oil is
used as fuel.
EPA has adopted Method 12 as the standard method for measuring inorganic lead emissions at
the source. In sampling, glass fiber filters are used to trap the paniculate lead in the front half of the
sampling train, and impingers containing nitric acid are used to trap lead condensates in the back half.
Lead paniculate is then extracted from the front-half catch of the sample with nitric acid and
combined with the back-half catch, to give total lead. Analysis is performed by atomic absorption.
39
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The following guidance is to be used in preparing or revising AP-42 sections describing
processes from which lead is emitted:
1. Lead emission factors are to be expressed as the weight of elemental lead, not as the weight
of the compounds that are actually emitted.
2. The emission factor table is to be footnoted to caution the user not to compare the lead
emission weight to the particulate matter emission weight.
3. The lead emission factor should be the sum of both the front-half and back-half catches of
EPA Method 12. If not, indicate the measurement method in a footnote.
4. If data are available on the specific compounds emitted, present this information in a
footnote to the emission factor table.
5. If the weight percent of lead compounds in the particulate emissions is known,
present this information in a footnote.
40
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Appendix A.
AP-42 SECTION REVISION PROCEDURES
A-l
-------
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-------
Appendix B.
EXAMPLE AP-42 SECTION
B-l
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B-2
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1.10 RESIDENTIAL WOOD STOVES
1.10.1 General1'2
Wood stoves are commonly used in residences as space heaters. They are used both as the
primary source of residential heat and to supplement conventional heating systems.
Because of differences in both the magnitude and the composition of the emissions, five
different categories should be considered when estimating emissions from wood burning devices:
- the conventional wood stove,
- the noncatalytic wood stove,
- the catalytic wood stove,
- the pellet stove, and
- the masonry heater.
Among these categories, there are many variations in device design and operation characteristics.
The conventional stove category comprises all stoves without catalytic combustors not
included in the other noncatalytic categories (i. e., noncatalytic and pellet). Conventional stoves do
not have any emission reduction technology or design features and, in most cases, were manufactured
before July 1, 1986. Stoves of many different air flow designs may be in mis category, such as
updraft, downdraft, crossdraft and S-flow.
Noncatalytic wood stoves are those units that do not employ catalysts but that do have
emission reducing technology or features. A typical noncatalytic design includes baffles and
secondary combustion chambers.
Catalytic stoves are equipped with a ceramic or metal honeycomb device, called a combustor
or converter, mat is coated with a noble metal such as platinum or palladium. The catalyst material
reduces the ignition temperature of the unburned volatile organic compounds (VOQ and carbon
monoxide (CO) hi the exhaust gases, thus augmenting their ignition and combustion at normal stove
operating temperatures. As these components of the gases burn, the temperature inside the catalyst
increases to a point at which the ignition of the gases is essentially self sustaining.
Pellet stoves are those fueled with pellets of sawdust, wood products, and other biomass
materials pressed into manageable shapes and sizes. These stoves have active air flow systems and a
unique grate design to accommodate this type of fuel. Some pellet stove models are subject to the
1988 New Source Performance Standards (NSPS), while others are exempt because of a high air-to-
fuel ratio (i. e., greater than 35 to 1).
External Combustion Sources 1.10-1
-------
Masonry heaters are large, enclosed chambers made of masonry products or a combination of
masonry products and ceramic materials. These devices are exempt from the 1988 NSPS because of
their weight (i. e., greater than 800 kg). Masonry heaters are gaming popularity as a cleaner burning
and heat efficient form of primary and supplemental heat, relative to some other types of wood
heaters. In a masonry heater, a complete charge of wood is burned in a relatively short period of
tune. The use of masonry materials promotes heat transfer. Thus, radiant heat from the heater
warms the surrounding area for many hours after the fire has burned out.
1.10.2 Emissions1-3-29
. The combustion and pyrolysis of wood hi wood stoves produce atmospheric emissions of
paniculate matter, carbon monoxide, nitrogen oxides, organic compounds, mineral residues, and to a
lesser extent, sulfur oxides. The quantities and types of emissions are highly variable, depending on a
number of factors, including stages of the combustion cycle. During initial burning stages, after a
new wood charge is introduced, emissions (primarily VOCs) increase dramatically. After the initial
period of high burn rate, there is a charcoal stage of the burn cycle characterized by a slower bum
rate and decreased emissions. Emission rates during this stage are cyclical, characterized by
relatively long periods of low emissions and shorter episodes of emission spikes.
Paniculate emissions are defined hi this discussion as the total catch measured by the EPA
Method 5H (Oregon Method 7) sampling train. A small portion of wood stove paniculate emissions
includes "solid" panicles of elemental carbon and wood. The vast majority of paniculate emissions is
condensed organic products of incomplete combustion equal to or less than 10 micrometers in
aerodynamic diameter (PM-10). Although reported panicle size data are scarce, one reference states
that 95 percent of the particles emitted from a wood stove were less than 0.4 micrometers hi size.
Sulfur oxides (SOJ are formed by oxidation of sulfur hi the wood. Nitrogen oxides (NOJ
are formed by oxidation of fuel and atmospheric nitrogen. Mineral constituents, such as potassium
and sodium compounds, are released from the wood matrix during combustion.
The high levels of organic compound and CO emissions are results of incomplete combustion
of the wood. Organic constituents of wood smoke vary considerably hi both type and volatility.
These constituents include simple hydrocarbons of carbon numbers 1 through 7 (Cl - C7) (which
exist as gases or which volatilize at ambient conditions) and complex low volatility substances that
condense at ambient conditions. These low volatility condensible materials generally are considered
to have boiling points below 300°C (572°F).
Polycyclic organic matter (POM) is an important component of the condensible fraction of
wood smoke. POM contains a wide range of compounds, including organic compounds formed
through incomplete combustion by the combination of free radical species hi the flame zone. This
group, which is classified as a Hazardous Air Pollutant (HAP) under Title ffl of the 1990 Clean Air
Act Amendments, contains the subgroup of hydrocarbons called Polycyclic Aromatic Hydrocarbons
(PAH).
Emission factors and their ratings for wood combustion hi residential wood stoves, pellet
stoves and masonry heaters are presented below hi Tables 1.10-1 through 1.10-8. The analysis
leading to the derivation of these emission factors is contained hi the emission factor documentation.
These tables contain emission factors for criteria pollutants (PM-10, CO, NOZ, SOJ, CO2, Total
1.10-2 EMISSION FACTORS
-------
Organic Compounds (TOO, speciated organic compounds, PAH, and some elements. The emission
factors are presented by wood heater type. PM-10 and CO emission factors are further classified by
stove certification category. Phase n stoves are those certified to meet the July 1, 1990 EPA
standards; Phase I stoves meet only the July 1, 1988 EPA standards; and Pre-Phase I stoves do not
meet any of the EPA standards but in most cases do necessarily meet the Oregon 1986 certification
standards. The emission factors for Paniculate and CO in Tables 1.10-1 and 1.10-2 are averages,
derived entirely from field test data obtained under actual operating conditions. Still, there is a
potential for higher emissions from some wood stove, pellet stove and masonry heater models.
As mentioned, paniculate emissions are defined as the total emissions equivalent to those
collected by EPA Method 5H. This method employs a heated filter followed by three impingers, an
unheated filter, and a final impinger. Paniculate emission factors are presented as values equivalent
to those collected with Method 5H. 'Conversions are employed, as appropriate, for data collected
with other methods.
Table 1.10-7 shows net efficiencies by device type, as determined entirely from field test data.
A net or overall efficiency is the product of combustion efficiency multiplied by heat transfer
efficiency. Wood heater efficiency is an important parameter used, along with emission factors, and
percent degradation, when calculating PM-10 emission reduction credits. Percent degradation is
related to the loss in effectiveness of a wood stove control device or catalyst over a period of
operation. Control degradation for any stove, including noncatalytic wood stoves, may also occur as
a result of deteriorated seals and gaskets, misaligned baffles and bypass mechanisms, broken
refractories, or other damaged functional components. The increase in emissions which can result
from control degradation has not been quantified. However, recent wood stove testing in Colorado
and Oregon should produce results which will allow estimation of emissions as a function of stove
age.
External Combustion Sources 1.10-3
-------
Table 1.10-1 (Metric Units). EMISSION FACTORS FOR RESIDENTIAL WOOD COMBUSTION'
Pollutant/EPA
Certification1*
Emission
Factor
Rating
Wood Stove Type
Conventional
(SCC 2104008051)
Noncatalytic
(SCC 2104008050)
Catalytic
(SCC 2104008030)
Pellet Stove Type"
(SCC 2104008053)
Certified
Exempt
Masonry Heater
(SCC 2104008055)
Exempt*
PM-10*
Pro-Phase I
Phase I
Phase H
All
Carbon Monoxide*
Pro-Phase I
Phase I
Phase D
All
Nitrogen Oxides*
Sulfur Oxides*
Carbon Dioxide'
TOd
Methane
TNMOC
"'.•"•"' '
B
B
B
B
B
B
B
B
B
C
E
E
E
15.3
15.3
115.4
115.4
1.4'
0.2
24.3
2.4
21.9
12.9
10.0
7.3
9.8
70.4
70.4
0.2
12.1
9.8
8.1
10.2
52.2
52.2
1.0-
0.2
12.1
4.3
7.8
2.1
2.1 4.4
19.7
19.7 26.1
6.9*
0.2
1,475.8 1,835.6
2.8
74.5
1,924.7
•Units are grama of pollutant/kg of dry wood burned. SCC = Source Classification Code.
bPre-Phase I = Not certified to 1988 EPA emission standards; Phase I = Certified to 1988 EPA emission standards;
Phase II = Certified to 1990 EPA emission standards; All = Average of emission factors for all devices.
"Certified = Certified pursuant to 1988 NSPS; Exempt = Exempt from 1988 NSPS (i. e., airfuel >35:1).
'Exempt = Exempt from 1988 NSPS (i. e., device weight >800 kg).
•References 6-14,23-27,29. PM-10 is defined as equivalent to total catch by EPA method 5H train.
•EMISSION FACTOR RATING = C.
•EMISSION FACTOR RATING = E.
•References 13,24-27,29.
'References 13,17-18. TOC = Total organic compounds. TNMOC = Total nonmethane organic compounds. Data show a high degree of variability within
the source population. Factors may not be accurate for individual sources.
-------
Table 1.10-2 (English Units). EMISSION FACTORS FOR RESIDENTIAL WOOD COMBUSTION*
Pollutant/EPA
Certification1"
Emission
Factor
Rating
Wood Stove Type
Conventional
(SCC 2104008051)
Noncatalytic
(SCC 2104008050)
Catalytic
(SCC 2104008030)
Pellet Stove Type"
(SCC 2104008053)
Certified
Exempt
Masonry Heater
(SCC
2104008055)
Exempt*
PM-10"
Pro-Phase
Phasel
Phase n
All
Carbon Monoxide"
Pre-Phase I
Phasel
Phase 0
All
Nitrogen Oxides*
Sulfur Oxides*
Carbon Dioxide*
TOC'
Methane
TNMOC
B
B
B
B
B
B
B
B
B
C
E
E
E
30.6
30.6
230.8
230.8
2.8'
0.4
48.6
4.8
43.8
25.8
20.0
14.6
19.6
140.8
140.8
0.4
24.2
19.6
16.2
20.4
104.4
107.0
104.4
2.0»
0.4
24.2
8.6
15.6
4.2
4.2 8.8
39.4
39.4 52.2
13.8«
0.4
2,951.6 3,671.2
5.6
149.0
3,849.4
'Units are Ibs. of pollutant/ton of dry wood burned. SCC = Source Classification Code.
bPre-Phase I = Not certified to 1988 EPA emission standards. Phase I = Certified to 1988 EPA emission standards.
Phase n = Certified to 1990 EPA emission standards; All = Average of emission factors for all devices.
"Certified = Certified pursuant to 1988 NSPS. Exempt = Exempt from 1988 NSPS (i. e., airfuel >35:1).
'Exempt = Exempt from 1988 NSPS (i. e., device weight >800 kg).
•References 6-14,23-27,29. PM-10 is defined as equivalent to total catch by EPA method 5H train.
•EMISSION FACTOR RATING = C.
•EMISSION FACTOR RATING = E.
"•References 13,24-27,29.
References 13,17-18. TOC = Total organic compounds. TNMOC = Total nonmethane organic compounds. Data show a high degree of variability within
H- the source population. Factors may not be accurate for individual sources.
i
-------
Table 1.10-3 (Metric And English Units). ORGANIC COMPOUND EMISSION FACTORS FOR
RESIDENTIAL WOOD COMBUSTION"-"
EMISSION FACTOR RATING: E
Compounds
Wood Stove Type
Conventional
(SCC 2104008051)
g/kg Ib/ton
Catalytic
(SCC 2104008030)
g/kg Ib/ton
Ethane
Ethylene
Acetylene
Propane
Propene
i-Butane
n-Butane
Butenese
Pentenesd
Benzene
Toluene
Furan
Methyl Ethyl Ketone
2-Methyl Furan
2,5-Dimethyl Furan
Furfural
O-Xylene
0.735
2.245
0.562
0.179
0.622
0.014
0.028
0.596
0.308
0.969
0.365
0.171
0.145
0.328
0.081
0.243
0.101
1.470
4.490
1.124
0.358
1.244
0.028
0.056
1.192
0.616
1.938
0.730
0.342
0.290
0.656
0.162
0.486
0.202
0.688
1.741
0.282
0.079
0.734
0.005
0.007
0.357
0.075
0.732
0.260
0.062
0.031
0.042
0.011
0.073
0.093
1.376
3.482
0.564
0.158
0.734
0.010
0.014
0.714
0.150
1.464
0.520
0.124
0.062
0.084
0.022
0.146
0.186
•Reference 17. Units are g of pollutant/kg and Ib. of pollutant/ton of dry wood burned. SCC =
Source Classification Code.
bData show a high degree of variability within the source population. Factors may not be accurate
for individual sources.
cl-butene, i-butene, t-2-butene, c-2-butene, 2-me-l-butene, 2-me-butene are reported as butenes.
dl-pentene, t-2-pentene, and c-2-pentene are reported as pentenes.
1.10-6 EMISSION FACTORS
-------
Table 1.10-4 (Metric Units). POLYCYCLIC AROMATIC HYDROCARBON (PAH) EMISSION
FACTORS FOR RESIDENTIAL WOOD COMBUSTION"-"
EMISSION FACTOR RATING: E
Pollutant
Stove Type
Conventional0
(SCC
2104008051)
Noncatalyticd
(SCC
2104008050)
Catalytic'
(SCC
2104008030)
Exempt Pellet5
(SCC
2104008053)
PAH
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)Anthracene
Benzo(b)Fluoranthene
Benzo(g,h,i)Fluoranthene
Benzo(k)Fluoranthene
Benzo(g,h,i)Perylene
Benzo(a)Pyrene
Benzo(e)Pyrene
Biphenyl
Chrysene
Dibenzo(a,h)Anthracene
7,12-Dimemylbenz(a) Anthracene
Fluoranthene
Fluorene
Indeno(l ,2,3,cd)Pyrene
9-Methylanthracene
12-Methylbenz(a)Anthracene
3-Methylchlolanthrene
1-Methylphenanthrene
Naphthalene
Nitronaphthalene
Perylene
Phenanthrene
Phenanthrol
Phenol
Pyrene
ToalPAH
0.005
0.106
0.007
0.010
0.003
0.001
0.002
0.002
0.006
0.006
0.000
0.010
0.012
0.000
0.144
0.039
0.012
0.365
0.005
0.016
0.004
<0.001
0.002
0.014
<0.001
0.010
0.003
0.001
0.011
0.005
0.002
0.002
0.004
0.007
0.010
0.002
0.001
<0.001
0.015
0.072
0.000
0.001
0.059
0.000
< 0.001
0.004
0.250
0.003
0.034
0.004
0.012
0.002
0.003
0.001
0.001
0.002
0.002
0.005
0.001
0.006
0.007
0.002
0.093
0.024
0.005
0.207
1.30E-05
3.76E-05
2.74E-05
1.66E-05
2.42E-05
'Units are g of pollutant/kg of dry wood burned. SCC = Source Classification Code.
bData show a high degree of variability within the source population and/or came from a small number of
sources. Factors may not be accurate for individual sources.
"Reference 17.
'References 15,18-20.
"References 14-18.
'Reference 27. Exempt = Exempt from 1988 NSPS (i. e., air fuel >35:1).
External Combustion Sources
1.10-7
-------
Table 1.10-5 (English Units). POLYCYCLIC AROMATIC HYDROCARBON (PAH) EMISSION
FACTORS FOR RESIDENTIAL WOOD COMBUSTION"-"
EMISSION FACTOR RATING: E
Pollutant
Stove Type
Conventional0
(SCC
2104008051)
Noncatalytic4
(SCC
2104008050)
Catalytic*
(SCC
2104008030)
Exempt Pellet'
(SCC
2104008053)
PAH
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)Anthracene
Benzo(b)Fluoranthene
Benzo(g,h,i)Fluoranthene
Benzo(k)Fluoranthene
Benzo(g>h,i)Peiylene
Benzo(a)Pyrene
Benzo(e)Pyrene
Biphenyl
Chrysene
Dibenzo(a,h)Anthracene
7,12Dimethylbenz(a)Anthracene
Fluoranthene
Fluorene
Indeno(l ,2,3,cd)Pyrene
9-Methylanthracene
12-Methylbenz(a)Anthracene
3-Methylchlolanthrene
1-Methylphenanthrene
Naphthalene
Nitronaphthalene
Perylene
Phenanthrene
Phenanthrol
Phenol
Pyrene
Total PAH
0.010
0.212
0.014
0.020
0.006
0.002
0.004
0.004
0.012
0.012
0.000
0.020
0.024
0.000
0.288
0.078
0.024
0.730
0.010
0.032
0.009
<0.001
0.004
0.028
<0.001
0.020
0.006
0.002
0.022
0.010
0.004
0.004
0.008
0.014
0.020
0.004
0.002
< 0.001
0.030
0.144
0.000
0.002
0.118
0.000
< 0.001
0.008
0.500
0.006
0.068
0.008
0.024
0.004
0.006
0.002
0.002
0.004
0.004
0.010
0.002
0.012
0.014
0.004
0.186
0.489
0.010
0.414
2.60E-05
7.52E-05
5.48E-05
3.32E-05
4.84E-05
•Units are Ib. of pollutant/ton of dry wood burned. SCC = Source Classification Code.
bData show a high degree of variability within the source population and/or came from a small number of
sources. Factors may not be accurate for individual sources.
"Reference 17.
'References 15,18-20.
•References 14-18.
'Reference 27. Exempt = Exempt from 1988 NSPS (i. e., air fuel >35:1).
1.10-8
EMISSION FACTORS
-------
Table 1.10-6 (Metric And English Units). TRACE ELEMENT EMISSION FACTORS FOR
RESIDENTIAL WOOD COMBUSTION*"
EMISSION FACTOR RATING: E
Element
Wood Stove Type
Conventional
(SCC 2104008051)
g/kg Ib/ton
Noncatalytic
(SCC 2104008050)
g/kg Ib/ton
Catalytic
(SCC 2104008030)
g/kg Ib/ton
Cadmium (Cd)
Chromium (Cr)
Manganese (Mn)
Nickel (Ni)
1.1E-05
<1.0E-06
8.7E-05
7.0E-06
2.2E-05
<1.0E-06
1.7E-04
1.4E-05
l.OE-05
<1.0E-06
7.0E-05
l.OE-05
2.0E-05
< l.OE-05
1.4E-04
2.0E-05
2.3E-05
<1.0E-06
1.1E-04
l.OE-06
4.6E-05
<1.0-E06
2.2E-04
2.2E-06
•References 14,17. Units are g of pollutant/kg and Ib. of pollutant/ton of dry wood burned.
SCC = Source Classification Code.
The data used to develop these emission factors showed a high degree of variability within the source
population. Factors may not be accurate for individual sources.
Table 1.10-7. SUMMARY OF WOOD HEATER NET EFFICIENCIES'
Wood Heater Type Source
Classification
Code
Wood Stove
Conventional 2104008051
Noncatalytic 2104008050
Catalytic 2104008030
Pellet Stoveb
Certified 2104008053
Exempt
Masonry Heater 2104008055
Net Efficiency (%) Reference
54 26
68 9, 12,
26
68 6,26
68 11
56 27
58 28
"Net efficiency is a function of bom combustion efficiency and heat transfer efficiency. Percentages
shown are based on in-home test data.
"•Certified = Certified pursuant to 1988 NSPS. Exempt = Exempt from 1988 NSPS (i. e., airrfuel
External Combustion Sources
1.10-9
-------
References for Section 1.10
1. Standards Of Performance For New Stationary Sources: New Residential Wood Heaters, 53 FR
5573, February 26, 1988.
2. R. Gay and J. Shah, Technical Support Document For Residential Wood Combustion, EPA-450/4-85-
012, U. S. Environmental Protection Agency, Research Triangle Park, NC, February 1986.
3. J. A. Rau and J. J. Huntzicker, "Composition And Size Distribution Of Residential Wood Smoke
Aerosols", Presented at the 21st Annual Meeting of the Air And Waste Management Association,
Pacific Northwest International Section, Portland, OR, November 1984.
4. C. A. Simons, et al., Whitehorse Efficient Woodheat Demonstration, The City of Whitehorse,
Whitehorse, Yukon, Canada, September 1987.
5. C. A. Simons, et al., Wbodstove Emission Sampling Methods Comparability Analysis And In-situ
Evaluation Of New Technology Woodstoves, EPA-600/7-89-002, U. S. Environmental Protection
Agency, Cincinnati, OH, January 1989.
6. S. G. Barnett, Field Performance Of Advanced Technology Woodstoves In dens Falls, N. Y., 1988-
1988, Vol. 1, New York State Energy Research And Development Authority, Albany, NY, October
1989.
7. P. G. Burnet, The Northeast Cooperative Woodstove Study, Volume 1, EPA-600/7-87-026a, U. S.
Environmental Protection Agency, Cincinnati, OH, November 1987.
8. D. R. Jaasma and M. R. Champion, Field Performance OfWoodbuming Stoves In Crested Butte
During The 1989-90 Heating Season, Town of Crested Butte, Crested Butte, CO, September 1990.
9. S. Dernbach, Woodstove Field Performance In Klamath Falls, OR, Wood Heating Alliance,
Washington, DC, April 1990.
10. C. A. Simon and S. K. Jones, Performance Evaluation Of The Best Existing Stove Technology
(BEST) Hybrid Woodstove And Catalytic Retrofit Device, Oregon Department of Environmental
Quality, Portland, OR, July 1989.
11. S. G. Barnett and R. B. Roholt, In-home Performance Of Certified Pellet Stoves In MedfordAnd
Klamath Falls, OR, U. S. Department Of Energy Report No. PS407-02, Washington, DC, July
1990.
12. S. G. Barnett, In-home Evaluation Of Emission Characteristics Of EPA-certified High-tech Non-
catafytic Woodstoves In Klamath Falls, OR, 1990, DSS File 145Q, 23440-9-9230, Canada Center For
Mineral And Energy Technology, Energy, Mines and Resources, Ottowa, Canada, June 1, 1990.
13. R. C. McCrillis and R. G. Merrill, "Emission Control Effectiveness Of A Woodstove Catalyst And
Emission Measurement Methods Comparison", Presented at the 78th Annual Meeting of the Air And
Waste Management Association, Detroit, MI, 1985.
1.10-10 EMISSION FACTORS
-------
14. K. E. Leese and S. M. Harkins, Effects Of Burn Rate, Wood Species, Moisture Content And Weight
Of Wood Loaded On Woodstove Emissions, EPA-600/2-89-025, U. S. Environmental Protection
Agency, Cincinnati, OH, May 1989.
15. J. M. Allen and W. M. Cooke, Control Of Emissions From Residential Wood Burning By
Combustion Modification, EPA-600/7-81-091, U. S. Environmental Protection Agency, Cincinnati,
OH, May 1981.
16. D. G. DeAngelis, et al., Preliminary Characterization Of Emissions From Wood-fired Residential
Combustion Equipment, EPA-600/7-80-040, U.S. Environmental Protection Agency, Cincinnati,
OH, March 1980.
17. P. G. Burnet, et al., Effects Of Appliance Type And Operating Variables On Woodstove Emissions,
Vol. /., EPA-600/2-90-001a, U. S. Environmental Protection Agency, Cincinnati, OH, January 1990.
18. L. E. Cottone and E. Mesner, Test Method Evaluations And Emissions Testing For Rating Wood
Stoves, EPA-600/2-86-100, U. S. Environmental Protection Agency, Cincinniati, OH, October 1986.
19. Residential Wood Heater Test Report, Phase II Testing, Vol. 1, Division Of Energy, Construction
And Rates, Tennessee Valley Authority, Chattanooga, TN, August 1983.
20: R. S. Truesdale and J. G. Cleland, "Residential Stove Emissions From Coal And Other Alternative
Fuels Combustion", delivered at the Specialty Conference on Residential Wood And Coal
Combustion, Louisville, KY, March 1982.
21. S. G. Barnett, In-home Evaluation Of Emissions From Masonry Fireplaces And Heaters, OMNI
Environmental Services, Inc., Beaverton, OR, September 1991.
22. S. G. Barnett, In-home Evaluation Of Emissions From A Grundofen Masonry Heater, OMNI
Environmental Services, Inc., Beaverton, OR, January 1992.
23. S. G. Barnett, In-home Evaluation Of Emissions From A TuWdvi KTU 2100 Masonry Heater, OMNI
Environmental Services, Inc., Beaverton, OR, March 1992.
24. S. G. Barnett, In-home Evaluation Of Emissions From A Royal Crown 2000 Masonry Heater, OMNI
Environmental Services, Inc., Beaverton, OR, March 1992.
25. S. G. Barnett, In-home Evaluation Of Emissions From A Biofire 4x3 Masonry Heater, OMNI
Environmental Services, Inc., Beaverton, OR, March 1992.
26. S. G. Barnett and R. D. Bighouse, In-home Demonstrations Of The Reduction Of Woodstove
Emissions From The Use OfDensifiedLogs, Oregon Department Of Energy and U. S. Environmental
Protection Agency, Salem OR, July 1992.
27. S. G. Barnett and P. G. Fields, In-home Performance Of Exempt Pellet Stoves In Medfard, Oregon,
U. S. Department Of Energy, Oregon Department Of Energy, Tennessee Valley Authority, and
Oregon Department Of Environmental Quality, Salem, OR, July 1991.
External Combustion Sources 1.10-11
-------
28. S. G. Barnett, Summary Report Of The In-home Emissions And Efficiency Performance Of Five
Commercially Available Masonry Heaters, The Masonry Heater Association, Reston, VA, May 1992.
29. Emission Factor Documentation For AP-42 Section 1.10, Residential Wood Stoves, Office Of Air
Quality Planning And Standards, U. S. Environmental Protection Agency, Research Triangle Park,
NC, April 1993.
1.10-12 EMISSION FACTORS
-------
TECHNICAL REPORT DATA
(Pleat nod Instructions on the reverse before completing)
1. REPORT NO.
EPA-454/B-93-050
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Technical Procedures For Developing AP-42 Emission
Factors And Preparing AP-42 Sections
5. REPORT DATE
October 1993
6. PERFORMING ORGANIZATION CODE
7.AUTH0R(s> Emission inventory Branch
Office Of Air Quality Planning And Standards
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Emission Inventory Branch
Technical Support Division (MD 14)
Office Of Air Quality Planning And Standards
US EPA 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
18. SUPPLEMENTARY NOTES
Editor: Whitmel M. Joyner
16. ABSTRACT
This document is a guide to developing emission factors and producing portions
of the Compilation Of Air Pollutant Emission Factors. AP-42. It contains
guidance on the technical and editorial quality required of material tb:become
part of the AP-42 series of EPA documents.
The guidance is a necessity for those involved in the AP-42 production
process.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
AP-42 Emission Factors
AP-42 Technical Standards
AP-42 Editorial Format & Standards
AP-42 Background Files
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS (This Report)
21. NO. Or PAGES
64
20. SECURITY CLASS (Thispage)
22. PRICE
EPA ftrm 2220-1 (R««. 4-77) PMKVIOIM KDITION is OMOLBTK
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