EPA-454/R-95-015
PROCEDURES FOR
PREPARING EMISSION FACTOR
DOCUMENTS
Office of Air Quality Planning and Standards
Office of Air and Radiation
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
May 1997
Protection Agency
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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 as received from the contractor. Approval does
not signify that the contents necessarily reflect the views and policies of the Agency, neither does mention of
trade names or commercial products constitute endorsement or recommendation for use.
EPA-454/R-95-015
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CONTENTS
Page
CHAPTER 1 -PURPOSE OF THIS DOCUMENT l-l
CHAPTER2 - INTRODUCTION TO EMISSION FACTORS 2-1
2.1 DEFINITION OF AN EMISSION FACTOR 2-1
2.2 USES AND LIMITATIONS OF FACTORS 2-1
2.3 VARIABILITY OF EMISSIONS 2-4
2.4 POLLUTANTS REPRESENTED '. 2-4
2.4.1 Pollutant Terminology and Conventions 2-4
2.4.2 TestMethods 2-8
2.5 REASONS AND METHODS FOR INITIATING SECTION
PREPARATION AND REVIEW 2-10
2.6 MECHANISMS FOR INITIATING REVISIONS TO AP-42 2-12
2.6.1 Internal Prioritizations/EPA Needs 2-12
2.6.2 State/Local Emission Factor Initiatives 2-12
2.6.3 Industry Initiatives 2-13
2.7 EPA's PUBLIC PARTICIPATION PROCEDURES 2-13
CHAPTERS -UPDATE PROCEDURES AND INFORMATION FLOW 3-1
3.1 PRELIMINARY DATA SCREENING 3-1
3.2 ADDITIONAL DATA COLLECTION 3-1
3.3 DRAFTING DOCUMENTS 3-1
3.4 INTERNAL REVIEW 3.3
3.5 EXTERNAL REVIEW 3.3
3.6 FlNALIZATION OF DOCUMENT 3-3
3.7 DISTRIBUTION MECHANISMS 3-4
3.7.1 Hard Copy 3-4
3.7.2 Fax CHIEF 3-4
3.7.3 CHIEF BULLETIN BOARD SYSTEM (BBS) 3-4
3.7.4 FIRE 3-5
3.7.5 Air CHIEF CD-ROM 3-5
3.8 ERRATA PROCEDURES 3.5
CHAPTER 4 - FACTOR DEVELOPMENT AND PRESENTATION DETAILS 4-1
4.1 CONTENT AND FORMAT OF A TYPICAL AP-42 SECTION 4-1
4.2 CONTENT AND FORMAT OF A TYPICAL L&E DOCUMENT 4-3
4.3 DATA COLLECTION AND REVIEW 4.4
4.3.1 AP-42 Background Files 4-4
4.3.2 Literature Search 4.4
4.3.3 Emission Factor Databases 4-5
4.3.4 EPA and Other Federal Agency Contacts 4-6
4.3.5 State and Local Agency Contacts 4-7
4.3.6 Industry Contacts and Trade Associations 4-7
4.4 DATA EVALUATION AND ANALYSIS 4-8
4.4.1 Evaluation of Primary and Secondary Data 4-8
4.4.2 Assign Data Quality Rankings 4-11
in
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CONTENTS (CONTINUED)
4.5
4.6
4.7
-
4.8
GROUP THE EMISSION DATA
DEVELOP CANDIDATE EMISSION FACTORS AND DRAFT SECTION
4.6.1 Averaging of Data
4.6.2 Combining Tests of Different Quality Ratings
4.6.3 Controlled Emission Factors
4.6.4 Outliers !
4.6.5 Detection Limits '
4.6.6 Use of Blanks :
4.6.7 Units of Measure and Activity Parameter Selection
4.6.8 Assign Emission Factor Ratings
469 Rounding and Significant Figures
BACKGROUND DOCUMENTATION
4.7. 1 Background Documents
4.7.2 Background Files
AFTER EXTERNAL REVIEW
4.8.1 SCC/AMS Code Assignments
4.8.2 FIRE Data Entry
Page
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4-15
4-15
4-17
4-17
4-19
4-20
4-22
4-22
4-24
4-25
4-26
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4-28
4-29
4-29
4-30
APPENDIX A AP-42 AND L&E EXAMPLES
APPENDDC B PUBLIC PARTICIPATION PROCEDURES
APPENDIX C F-FACTOR METHOD
APPENDIX D HAZARDOUS AIR POLLUTANTS
APPENDIX C ACRONYMS
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CHAPTER 1
PURPOSE OF THIS DOCUMENT
The purposes of this document are to describe the procedures, technical criteria, and standards and
specifications for developing and reporting air pollutant emission factors or equations for publication in
either the Compilation Of Air Pollutant Emission Factors, Volume 1: Stationary Point and Area Sources,
(AP-42) or the Locating and Estimating Air Toxic Emissions from (or of) (Source Category of Substance)
(L&E) document series. Both AP-42 Volume I and the L&E series are published by the Emission Factor and
Inventory Group (EFIG) in EPA's Office of Air Quality Planning and Standards (OAQPS). The procedures in
this document may be different than those described for AP-42 Volume II: Mobile Sources, produced by
EPA's Office of Mobile Sources in Ann Arbor, Michigan.
Previous editions of this manual have served as a guide for EPA personnel and their contractors
preparing AP-42 sections. This edition has been revised to include guidance for preparing L&E documents
and to assist industry, trade associations, and state and local agencies that may be involved in developing or
revising emission factors or equations. Guidance has also been added to describe how to report the factors
developed for AP-42 or an L&E document into EPA's electronic distribution mechanisms. The material in
this document is intended as guidance that should be followed when practicable .
Emission factors have long been used as a cost-effective means to develop area-wide emission
inventories. Emission inventories are fundamental tools for air quality management. They are used for
identifying major contributors of atmospheric pollutants, developing emission control strategies, determining
applicability of permitting programs, and other related applications by an array of users including federal,
State, and local agencies, consultants, and industry.
AP-42 has been published since 1972 as the primary compilation of EPA's emission factor
information It contains emission factors and process information for more than 200 air pollution source
categories A source category is a specific industry sector or group of similar emitting sources. The emission
factors have been developed and compiled from source test data, material balance studies, and engineering
estimates The Fifth Edition of AP-42 was published in January 1995. Supplements to the Fifth Edition will
be published approximately annually and will contain new sections on additional source categories as well as
revisions to existing sections.
The L&E series was initiated in 1984, and now consists of 36 individual documents. Unlike the
source category organization of AP-42, most L&E documents focus on all sources of a specific hazardous air
pollutant or related group of pollutants. L&E documents make use of AP-42 emission factors where
applicable, and they also revise or supplement those emission factors when necessary to present the most
complete assessment of the sources of the specific air pollutant. In addition to providing emission factors and
process descriptions, the most recently published L&E documents attempt to quantify the national emissions
of the pollutant.
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Chapter 1 Purpose of This Document
Chapter 2 provides background on emission factors and their uses and limitations. It describes the
pollutant terminology used in AP-42 and discusses some of the emission test methods used to measure these
pollutants. The reasons and procedures for initiating revisions to emission factors are also discussed.
Chapter 3 provides an overview of the sequential tasks involved in revising or developing emission
factors. It describes the update procedures ans discusses EPA's various tools for disseminating information.
Chapter 4 provides the details on how the tasks outlined in Chapter 3 can best be accomplished, from
data collection through data evaluation and external reviews, to the determination of final emission factors.
Sections are included on typical contents, data collection, data review, developing and presenting emission
factors, and background documentation.
Appendix A presents a typical AP-42 section and an L&E document as examples of the editorial
specifications to be used. Specifications are given for both the published paper copy and electronic versions
of the documents. Appendix B contains EFIG's Public Participation Plan and Appendix C contains a
description of using the F-factor method for determining pollutant emission rates using pollutant
concentrations in the exhaust stream of a combustion source and the oxygen concentration. Appendix D is a
listing of the 188 Hazardous Air Pollutants.
Notice to Users of this Guidance - Section 130 of the 1990 Amendments to the CAA provides for public
participation in the development of emission factors. This is discussed further in Appendix B. Since no two
emission factor development situations are exactly the same, EPA strongly encourages users of this document
to maintain close coordination with EPA and appropriate State/local/Tribal Agencies to ensure that EPA will
be able to use their work products. Also, this document will be revised periodically and the user is
encouraged to obtain the latest version of this document.
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CHAPTER 2
INTRODUCTION TO EMISSION FACTORS
2.1 DEFINITION OF AN EMISSION FACTOR
An emission factor is a tool that is used to estimate air pollutant emissions to the atmosphere. It
relates the quantity of pollutants released from a source to some activity associated with those emissions.
Emission factors are usually expressed as the weight of pollutant emitted divided by a unit weight, volume,
distance, or duration of the activity emitting the pollutant (e.g., pounds of paniculate matter emitted per ton
of coal burned). Emission factors are used to estimate a source's emissions by the general equation:
E = AxEFx [HER/100)]
where:
E = emissions,
A = activity rate,
EF = uncontrolled emission factor, and
ER = overall emission reduction efficiency. %.
(ER is the product of the control device destruction or removal efficiency and the capture
efficiency of the control system. When estimating emissions for a long time period (e.g., 1
year), both the device and the capture efficiency terms should account for upset periods as
well as routine operations.)
In most cases, these emission factors are simply averages of available data of acceptable quality, and
are generally assumed to be representative of long-term averages for all facilities in the source category (i.e.. a
population average) Usually, the available data are insufficient to indicate the influence of various process
parameters, such as temperature and reactant concentrations. For a few cases, however, such as in estimating
emissions from petroleum storage tanks, the AP-42 document contains empirical formulas (or emission
models) that relate emissions to variables such as tank diameter, liquid temperature, and wind velocity.
Emission factor formulas that account for the influence of such variables tend to yield more realistic estimates
(if information for all variables is accurate) than would emission factors that do not consider those
parameters. Emission factor ratings in the AP-42 or L&E document series provide indications of the
robustness, or appropriateness, of emission factors for estimating average emissions for a source activity.
2.2 USES AND LIMITATIONS OF EMISSION FACTORS
Emission factors in AP-42 or L&E documents are appropriate to use in developing emission
estimates for emission inventories. These inventories have many purposes including ambient dispersion
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Chapter 2 Introduction to Emission Factors
modeling and analysis, control strategy development, and screening of sources for compliance determinations.
However, because emission factors represent average emission rates for an entire source category, they are
not recommended as emission limits or standards for any specific source. Actual test results from source-
specific tests or continuous emission monitoring systems (CEMS), when properly done, are more indicative
of actual emissions for a specific source. When source-specific information is not available, use of emission
factors may be necessary. Whenever AP-42 or L&E emission factors are used, one should be aware of their
limitations in accurately representing the emissions from a particular facility, and the risks of using emission
factors in such situations should be evaluated against the costs of further testing or analyses.
Before simply applying AP-42 or L&E emission factors to predict emissions from new or planned
sources, or to make other source-specific emission assessments, the user should review the latest literature
and technology to see how the new technology differs from those of other, typical existing sources. The
source type and design, controls, and raw material input in particular should be reviewed. The age of the
information and the user's knowledge of the technology advances in the source category should also be
considered.
Estimates of short-term or peak (e.g., daily or hourly) emissions for specific sources are often needed
for regulatory purposes. Using emission factors to estimate short-term emissions will add further uncertainty
to the emission estimate. Short-term emissions from a single specific source often vary significantly with
time (i.e.. within-source variability) because of fluctuations in process operating conditions, control device
operating conditions, raw materials, ambient conditions, and other such factors. Emission factors generally
are developed to represent long-term average emissions, so testing is usually conducted at normal operating
conditions Thus, using emission factors to estimate short-term or otherwise atypical emissions will result in
even greater uncertainty. The AP-42 and L&E user should be aware of this limitation and should evaluate the
possible effects on the particular application.
For some sources, emission factors may be presented for processes having air pollution control
equipment in place. Emission factors noted as being for controlled sources do not necessarily reflect the best
available or state-of-the-art emissions levels for those control devices, but rather reflect the level of typical
control for which data were available at the time the tests were performed.
The fact that an emission factor for a pollutant or process is not available in AP-42 does not
necessarily mean that the source does not emit that pollutant or that the source should not be inventoried. It
may be simply be that no data for that source category are available for analysis. The question of whether the
source likely emits enough of a pollutant to warrant developing an emission estimate by some other method
must necessarily be made on a case-by-case basis, taking account of the needs or requirements of the
applicable air program.
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Chapter 2
Introduction to Emission Factors
Some emission factors are determined by using a material balance approach, which may provide
reliable average emission estimates for certain sources. For some sources, a material balance may provide a
better estimate of emissions than emission tests would. In general, material balances are appropriate for use
in situations where a high percentage of material is lost to the atmosphere (e.g., sulfur in fuel, or solvent loss
in an uncontrolled coating process.) In contrast, material balances may be inappropriate where material is
consumed or chemically combined in the process, or where losses to the atmosphere are a small portion of the
total process throughput. As the term implies, one needs to account for all the materials going into and
coming out of the process and for the uncertainty of each of the measured variables to make a credible and
reliable estimate of emissions.
Figure 2-1 depicts various emission estimation approaches that one should consider when analyzing
the tradeoffs between the cost of obtaining the estimates and the quality of the resulting estimates. Note that
Figure 2-1 only indicates a typical relationship between cost and reliability and that there is a wide range of
reliability possible for any one approach. Typically, using an emission factor to estimate emissions is cheaper
than a source test, but the emission estimate may not be as reliable, although an "A-rated" emission factor
may be as reliable as a CEMS. Selecting the protocol to be used to estimate source-specific emissions
warrants a case-by-case analysis considering the costs and risks in the specific situation. All sources and
regulatory agencies should be aware of these risks and costs and should assess them accordingly.
t
RISK SENSITIVITY EMISSION ESTIMATION APPROACHES
CEM
Parametric Source Tests
increasing
Cost
Single Source Tests
Material Balance
Source Category Emissions Model
Stateyinoustry Factors
Emsaon Factors (AP-42)
E
D
C
B
A
Engineering Judgment
Increasing Reliability of Estimate
Figure 2-1. Approach to emission estimation.
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Chapter 2 Introduction to Emission Factors
2.3 VARIABILITY OF EMISSIONS
Average emissions differ significantly from source to source and, therefore, emission factors
frequently, may not provide adequate estimates of the average emissions for a specific source. The extent of
between-source variability that exists, even among similar individual sources, can be large depending on
process, control system, and pollutant. Although some of the causes of this variability may be considered in
emission factor development, this type of information is seldom included in emission test reports used to
develop AP-42 or L&E emission factors. As a result, some emission factors are derived from tests whose
results may vary by orders of magnitude. Even when the major process variables are accounted for, the
emission factors developed may be the result of averaging source test results that differ significantly.
Air pollution control devices also may cause differing emission characteristics. The design criteria of
air pollution control equipment affect the resulting emissions. Design criteria include such items as the type
of wet scrubber used, the pressure drop across a scrubber, the plate area of an electrostatic precipitator, and
the alkali feed rate to an acid gas scrubber. Often, design criteria are not included in emission test reports (at
least not in a form conducive to detailed analysis of how varying process parameters can affect emissions)
and therefore may not be accounted for in the resulting emission factors.
In addition to the source-to-source variability discussed above, a single emission source will also
exhibit within-source variability. To assess within-source variability and the range of short-term emissions
from a source, one needs either a number of tests performed over an extended period of time or continuous
monitoring data from an individual source. Generally, material balance data are not likely to be sufficient for
assessing short-term emission variability because the accuracy of a material balance is greatly reduced for
shorter time intervals. In fact, one of the advantages of a material balance approach is that it averages out all
of the short-term fluctuations to provide a good long-term average.
2.4 POLLUTANTS REPRESENTED
The following sections describe the pollutant terminology and conventions typically used in AP-42
and L&E documents, and some of the difficulties in deriving emission factors for those pollutants from the
standard methods..
2.4.1 Pollutant Terminology
The AP-42 document provides emission factors for three main classifications of air pollutants:
criteria pollutants and their precursors, hazardous air pollutants (HAPs), and greenhouse gases. Additionally,
ammonia and stratospheric ozone depleters are mentioned. The criteria pollutants are the most extensively
covered, because they were the original focus of AP-42 and the Agency's regulatory efforts. Emission factors
for HAPs and greenhouse gases are being added as resources and available data allow.
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Chapter 2 Introduction to Emission Factors
Any information on the individual chemical species which make up a pollutant category, such as
VOC, paniculate matter (PM), or polycyclic organic matter (POM), may be included, even though the
quantification may not be as robust as for the total class. When individual compounds that comprise a class
are identified (e.g., benzo(a)pyrene, anthracene, etc. as congeners of POM), they should be grouped as
subsets of the class for clarity of presentation to the reader and to avoid double counting of emission totals.
Information on the split of organic compounds or paniculate matter into more specific categories or
individual compounds is very useful for some applications and should be included in the documents to the
extent possible.
It is often the case that the ideal measure of a pollutant may not be available, or even possible,
because of test method or data limitations, costs, or other problems. When such qualifications exist they
should be noted in the document. There may also be some potential overlap in measuring some compounds
(e.g., organic condensable PM and VOC). Acknowledgment of this should be noted in the document in either
the text or in a footnote to an emission factor table.
Criteria Pollutants and Precursors. The six criteria pollutants are sulfur dioxide, nitrogen oxides, carbon
monoxide, lead, paniculate matter less than 10 microns in diameter, and ozone (Note that at the time of this
printing the EPA is considering changing the basis of the ambient standard from PM10 to PM2.5). Nitrogen
oxides, carbon monoxide, and volatile organic compounds (VOC) are considered important because they are
precursors of the pollutant ozone. Additionally, ammonia, S02, nitrogen oxides, and VOC are also
considered precursors of PM.
Sulfur Dioxide (SO2) - The primary form of sulfur from the combustion of sulfur-containing fossil fuels is
sulfur dioxide. SO2. However, other oxidation states are usually formed as well. Emission factors can be
reported separately for S02 and SO3, or a combined emission factor for sulfur oxides (SOJ, can be presented.
A combined factor for SOX should be reported on the basis of the molecular weight of SO2. This means that
an SO, emission factor should be multiplied by the ratio of the molecular weights of SO2 to SO3 (64/80)
before being added to the SO2 emission factor. Sulfates (SO4) should be reported separately.
Nitrogen Oxides (NO^ - Another combustion byproduct is nitrogen oxide (NO). However, several other
nitrogen compounds are usually emitted at the same time (nitrogen dioxide (NO2), nitrous oxide (N2O), etc.),
and these may or may not be distinguishable in available test data. They are usually in a rapid state of flux,
with NO2 being, in the short term, the ultimate product emitted or formed shortly downstream of the stack.
The convention followed in emission factor documents is to report the distinctions wherever possible, but to
report total NOX on the basis of the molecular weight of N02.
Carbon Monoxide (CO) - Emission factors for CO are straightforward, since there is only one compound
involved. The emission factors are reported on the basis of the molecular weight of CO.
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Chapter 2 Introduction to Emission Factors
Lead (PB) - Lead is emitted and measured as participate matter and often will be reported for a process both
separately and as a component of the paniculate matter emission factor. The lead may exist as elemental lead
or as lead compounds (considered a HAP). The convention followed in emission factor documents is that the
total emissions of lead and lead compounds are expressed as the weight of the elemental lead. Lead
compounds can also be reported on the basis of the weight of those compounds if the distinction can be
made.
Paniculate Matter (PM) - Emission factor documents contain emission factors for various types and
sub-types of PM. PM is typically defined by the test method. Total PM refers to the amount of PM collected
in EPA Method 5 plus an EPA Method 202 sampling trains. Total filterable PM is the filter catch in the
Method 5 train. PM 10 refers to the amount of PM that is less than or equal to an aerodynamic diameter of 10
microns, and is usually the sum of the PM collected in EPA Method 201A and 202 sampling trains (Note that
the filter catch of 201A is sometimes referred to as "PM10", but is more correctly identified as "filterable
PM10"). There is no EPA Reference Method for PM2.5, but inertial size fractionation devices, such as
cascade impactors and cyclones, can be used to determine the filterable, or in-stack, portion of PM that is less
than an aerodynamic diameter of 2.5 microns. As in the case of PM10, condensable emissions should be
added to the in-stack emissions for a total PM2.S emission rate.
Unless noted, it is reasonable to assume that the PM emission results for processes that operate
above ambient temperatures are for filterable paniculate matter, as defined by EPA Method 5 or its
equivalent (a filter temperature of 250°F). Attempts to differentiate total paniculate matter and its
subcomponents, are made throughout the L&E and AP-42, where possible. Because of test method and data
limitations, and because some sources may not generate such components, the distinction is not always made.
Volatile Organic Compounds (VOC) - Many organic compounds react photochemically along with nitrogen
oxides and carbon monoxide to form the criteria pollutant ozone. EPA regulates a class of compounds called
VOC defined (in Title 40, Code of Federal Regulations, Part 51.100, February 3,1992) as "any compound of
carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, and
ammonium carbonate, which participates in atmospheric chemical reactions." A number of compounds are
deemed to have "negligible photochemical reactivity," and are therefore exempt from the definition of VOC.
The list of exempt compounds is occasionally expanded by subsequent Federal Register notices. As of June
1995, the list includes methane, ethane, methylene chloride, methyl chloroform, acetone, many
chlorofluorocarbons, and certain classes of perfluorocarbons.
For AP-42 sections, the goal is to present emission factors for VOC as a minimum. Emission
Factors for any of the exempted compounds, particularly methane as a greenhouse gas, may also be
presented if sufficient data are available. Emission factors for "total organic compounds" (TOC) may also be
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Chapter 2 ___ Introduction to Emission Factors
presented, although not as a substitute for the desired VOC emission factors. TOC is a term used to mean all
organics, including non-photoreactive compounds.
In many cases, data are not available to identify and quantify either the total mass of VOC (due to
some oxygenated compounds that are not completely measured by many common test methods) or the
specific components of TOC which should be subtracted to yield VOC. In such cases, the VOC emission
factor is annotated in an effort to provide clear and unambiguous data to the user. It is important for the
emission factor document author to note the test method and any assumptions that were used to develop the
emission factors.
When possible, report the emission factors in terms of actual weight of the emitted substance. When
the actual organic species present in the emissions are unknown, attempt an educated guess at the
composition and report as appropriate. If the actual species are unknown and an educated guess is not
feasible, calculate the VOC emissions at an assumed molecular weight of 44, and report "as propane".
Many organic compounds are also HAPs. Where individual HAP species can be quantified, an
emission factor representing their individual mass should be developed. This quantity should also be
included in the VOC or TOC emission factors, as appropriate.
Hazardous Air Pollutants fHAPsl. Title HI of the Clean Air Act Amendments of 1990 lists 188
toxic air pollutants defined for EPA regulatory purposes as HAPs. Appendix D provides a list of these
pollutants along with an indication of those in the Urban Air Toxics program (note that many states and other
authorities designate additional toxic or hazardous compounds). Although EPA may not have a published
reference method for all of these compounds, test methods are available to allow reasonably reliable
quantification of many compounds. Emission factors for such compounds should represent the actual total
mass of the compounds as emitted, not just the major element's mass (note that many test methods quantify
only the major element's mass, such as chromium or mercury). PM and VOC emission factors should include
any component species which are also separately identified and quantified as HAPs.
Greenhouse Gases. Carbon dioxide, methane, and nitrous oxide (N2O) are the principal greenhouse
gases being reported in AP-42 in addition to NOX, VOC, and CO. Each should be reported on the basis of the
compound's total molecular weight. Thus, modelers wishing to convert CO2 inventories given in tons will be
correct by assuming a molecular weight of 44. Note that this is not consistent with the convention used in
some applications of only accounting for the carbon mass of the emissions. CO2 emission factors for fuel
combustion are usually based on the assumption that essentially all of a fuel's carbon content is converted to
CO2 Industrial processes which produce CO2 emissions only from the combustion of fuel rather than from
the chemical reaction of some other raw material do not need to have CO2 emission factors developed and
reported in AP-42, since the emissions could be better estimated from the processes' fuel usage.
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Chapter! Introduction to Emission Factors
2.4.2 Test Methods
Historically, source tests have been the basis for the development of emission factors. EPA has
published reference methods for measuring emissions of PM/PM-10, S02, NOX, CO, inorganic lead, and
VOC. The reference methods, given in the 40 CFR Part 60, Appendix A, and Part 51, Appendix M, define
and describe the test equipment, materials, and procedures to be used in stack tests for the various criteria
pollutants. Methods for estimating HAP emissions are published in 40 CFR 61, Appendix B and EPA's SW-
846. The EPA publication, Screening Methods for the Development of Air Toxics Emission Factors,
EPA-450/4-91-021 Sept 91, presents an overview of the use of these reference methods for specific HAPs.
For further information, the reader can consult with the Emission Measurement Technical Information Center
(EMTIC), which provides technical guidance on stationary source emission testing. Individuals may access
EMTIC on the Ef»A's Technology Transfer BBS (919 541-5742) or the web site (www.epa.gov/oar/ttn-
bbs.html) or by calling EMTIC staff directly at (919) 541-0200.
Most of the EPA reference test methods were developed as a result of a standards development
project such as for a New Source Performance Standard (NSPS), National Emission Standard for Hazardous
Air Pollutant (NESHAP) or Maximum Achievable Control Technology (MACT). The test methods
developed for these projects were used as indicators of the level of control achieved when investigated during
the standards development effort. Two pollutants where this is most evident are PM and VOCs. Typically,
U.S. EPA Method 5 or one of its variants was used to judge whether a facility was meeting the PM standard
and Method 25 A was used to judge whether a facility was meeting the VOC standard.
In some cases, the source test method is an unbiased estimator of the actual emissions from a
process. Some examples of test methods that directly measure actual emissions are the EPA reference test
methods for CO, SO2, and NOX. The use of continuous emissions monitoring systems (CEMS) for these
pollutants will not only provide instantaneous or integrated estimates of emissions but may provide clues as
to the inherent variability of the emissions and can provide insight on those process variables that may have a
significant impact on the emissions. However, there are cases, such as with VOC and PM, where the test
method does not measure the pollutant exactly or only measures subsets of the pollutant. It is up to the
developer to be aware of the uses and limitations of test methods.
There are other test methods that do not directly measure the pollutant. This applies to EPA
reference test methods as well as others, hi many cases, this lack of direct measurement will have to be
accepted by the applicant, the permitting authority, and the reviewers, and they will have to recognize the fact
that the method is the best that is available. However, often an understanding of the method can overcome
shortcomings of the method.
Typically, EPA reference test methods for PM (EPA Methods 17,5, or 5x) measure only that
material that is collected on or ahead of the filter media of the sampling device. The material collected
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Chapter 2 Introduction to Emission Factors
depends upon the temperature at which the filter media are maintained. The filter media of EPA Method 17
is at stack temperature whereas the filter media of EPA Method 5 or 5x is maintained at about 250° F (or the
temperature specified in the method). As a result, these test methods only capture the non-gaseous material
and do not capture the vaporous material that will condense in the atmosphere. This material is referred to as
the filterable paniculate matter because it is the material mat can be filtered out of the gas stream at the
indicated temperature.
EPA Method 17 is similar to EPA Method 5 except that the filter is maintained at the temperature of
the flue gas. As a result of this usually higher filter temperature, somewhat less paniculate matter is collected
than would be in an EPA Method 5 sampling train. Other methods that are similar to Methods 5 and 17 are
the PM10 methods, EPA Methods 201 and 201 A. These methods measure in-stack PM10 and the difference
in these sampling trains is that the probe nozzle is replaced by a cyclone which has a aerodynamic cut size of
lOum. The method requires only that the material collected behind the cyclone up to the filter be recovered
and analyzed. Some source testers recover and weigh the material that is collected in and ahead of the
cyclone. The summing of this material with the material following the cyclone up to the filter will result in a
value similar to EPA Method 17. However, as with EPA Method 17, it may not give the same results as
EPA Method 5.
EPA Method 202 will determine the condensible PM emissions and will, when combined with the
results of EPA Methods 17,201 or 201 A, or 5, approximate the PM emissions that will exist in the ambient
environment. In the Method 202 analysis, the material that is collected in the impingers is extracted with
methylene chloride and separated into two fractions; an organic fraction and an aqueous or inorganic
fraction. The organic fraction is evaporated at room temperature and then quantitatively weighed. The
water in the aqueous fraction is boiled off to leave the inorganic material which is also quantitatively
weighed By combining all of the portions of quantitatively weighed material, the total paniculate matter
emissions that would occur in the ambient air can be determined. In combining all of these weighings, it
should be noted that there may be errors in combining data from different test methods. For example, the
combination of EPA Method 5 data with EPA Method 202 data following an EPA Method 17 sampler would
result in greater emissions than may actually occur. This is because some of the material collected in EPA
Method 5 would also be collected in the impinger portion following EPA Method 17. This difference
becomes greater as the differences between the stack temperature and the EPA Method 5 filter temperature
becomes greater and also as the relative amount of condensable material becomes greater.
The test methods that have been used to estimate organic emissions may not determine the actual
emissions of the pollutant defined as VOC. The test methods that are available for quantifying organic
emissions are EPA Methods 18,25, and 25 A. Each of these test methods measures organic compounds
differently. These differences depend upon the basic response factor of the instrument used and on
assumptions about the molecular weight of the compounds being determined.
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Chapter! Introduction to Emission Factors
EPA Method 18 has the potential to come the closest to estimating actual emissions of all of the
pollutants that are in the gas stream in major quantities. This is because each constituent is separated and
quantified individually, allowing the individual constituents molecular weights to be used in quantifying the
total mass emitted. If the instrument is correctly calibrated for each of the major species present in the
stream, the sum of all of the species can be an accurate measure of VOC or TOC. However, it is often not
possible to identify all of the species present and to calibrate for each one. This test method is seldom used
because of its complexity of operation and the time required to perform the analysis. Additionally, the test
may have been terminated prior to all compounds being measured.
EPA Method 25 separates the methane from the non-methane and converts all of the non-methane
organics to methane prior to being analyzed. As a result, the detector only sees methane, so the response
factor is constant and the total number of carbon atoms can be accurately determined. However, there is a
high minimum detectable limit (50 ppm as carbon) and a potential error is introduced when estimating the
total mass of the compounds as emitted because of errors in estimating the number of chlorine, oxygen,
hydrogen, or other atoms associated with each carbon atoms. Note that modifications of this method are
often used to measure only the non-methane organic compounds. However, ethane and other non-reactive
compounds would still he counted by this modified method, leading to an overestimate of VOCs if non-
reactive species are present in any significant quantity.
EPA Method 25A is the most commonly used test method for organic emissions. It is used because
it can provide continuous emissions measurement once it is set up and its operation is relatively straight-
forward. However, the response factors for this method vary for the different compounds that exist in the flue
gas The presence of oxygen or halogens depresses the response. In fact, the method has almost no response
to small chlorinated or oxygenated compounds, such as formaldehyde. Therefore, the results of a
Method 25 A test should be augmented by the amount of any formaldehyde determined by a separate method
when developing a VOC emission factor for sources where formaldehyde is present. Because Method 25A
does measure methane, ethane, and some other non-reactive compounds, VOCs may be overestimated even
when the response factors are corrected for the problem compounds. Thus care should be taken to evaluate
what compounds are expected from a source before labeling Method 25A results as "VOC".
Table 2-1 contains a list of the preferred methodologies, by pollutant, available for determining HAP
and criteria pollutant emissions from stack sampling.
2.5 REASONS AND METHODS FOR INITIATING SECTION PREPARATION AND REVISION
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 emission
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Chapter 2
Introduction to Emission Factors
factors. This increased emphasis on emission factor availability and quality contributed extensively to the
formation of EFIG.
Given this new emphasis on expanding the coverage and quality of 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:
Table 2-1. RECOMMENDED TEST METHODOLOGIES FOR HAZARDOUS AIR
POLLUTANTS AND CRITERIA POLLUTANTS
Pollutant
Test Method
SO2
NO,
O2/COj
CO
VOC*
Speciated organics
Metals and metal compounds (including lead)
PM, filterable
PM, condensable (considered < 1 um in size)
PM-10. filterable
EPA Method 6 and CEM Method
EPA Method 7 and CEM Method
EPA Method 3 and CEM Method
EPA Method 1 OB
*EPA Methods 25A and 0011 (formaldehyde) or
*EPA Method 25
EPA Methods 18,0030, and 0010
EPA Method 12
EPA Methods 5 and 17
EPA Method 202
EPA Methods 201 and 201A
*No test method directly measures VOC unless it is known that the source does not emit formaldehyde or any
of the non-photochemically reactive organics. Care should be taken to adjust for these species where they are
suspected of being significant
Outside requests for better source and emission factor information, or for information on a category
or pollutant not already addressed. Requests may come from other Groups within OAQPS, 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 Emission Standard Division (ESD) background documents
involving New Source Performance Standards, Maximum Achievable Control Technologies (MACT),
National Emissions Standards For Hazardous Air Pollutants (NESHAP), and Control Techniques Guidelines
(CTG), and from reports by various EPA laboratories.
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Chapter 2 Introduction to Emission Factors
Contractor or consultant expertise on a source category may have developed during previous work,
either for EPA or for other clients, and may warrant considering a relatively low-expense update and
expansion of available information.
Also, EFIG periodically performs assessments of the source activities covered by the AP-42 and
L&E document series and those not included to determine which, if any, source categories warrant future
efforts either to update an existing document or to develop a new one. ID addition to these possibilities,
Section 130 of the Clean Air Act Amendments (related to photochemical pollutants) emphasizes the process
through which any party may submit valid information to EFIG for review and publication (see paragraph
2.7).
The tasks of emission factor document preparation have historically been done either by Agency
personnel or by a contractor, depending on cost, time, and contractor qualifications, as the EFIG Leader
directs. Industry trade groups and industry groups have also been partners with EFIG in developing new
factors. These tasks include compilation or generation of data, data evaluation, and preparation of the draft
document, as well as EPA review, coordination of outside review, final editing and formatting, and
publication. As a results of section 130 of the CAAA, many of these tasks may be performed by an industry
group or a State or local agency.
2.6 MECHANISMS FOR INITIATING REVISIONS TO AJ*-42
2.6.1 Internal Prioritizations/EPA Needs
The AP-42 Team relies on several processes to establish the priorities for selecting the source
categories and sections to update or initiate. A prioritization scheme reflecting the impact of the particular
source category on national emissions, number of sites, localized problems, and other measures has been used
in the past
2.6.2 State/Local Emission Factor Initiatives
Beginning in the FY 96 budget year, Section 105 funding was identified for possible use by States
and local agencies for activities leading to the development and adoption of emission factors. These emission
factors may be developed to meet a unique situation within the jurisdiction (customized to meet those specific
conditions) or as a special effort to improve emission factors that are utilized by many. The EFIG staff
expects to be heavily involved in coordinating and consulting with these activities as they develop and the
expectation is that the EFIG staff will actually finalize the incoming revisions in AP-42 or will be the final
reviewer and quality assurance for guaranteeing that the information put into AP-42 is correct and complete.
One of the major roles of the EFIG staff in this area will be the conduct of these reviews and steering
activities to assure that funds spent on development of emission factors is carried out efficiently and with
technical integrity, and that they become available to the user community at large.
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Chapter 2 Introduction to Emission Factors
2.6.3 Industry Initiatives
There has been increased interest and efforts to work jointly with industry, usually a trade
association, to develop new and improved emission factors. This process will develop over time, but there is
a likelihood that there will be increased efforts on the part of industry to fund testing, propose new emission
factors, and even develop proposed new sections for AP-42. Part of the purpose of this document will be to
provide a clear understanding between the EPA and industry staffs of their roles and responsibilities (and
limits of flexibility) and the steps that must be followed to maintain integrity, believability and realization of
needs. This is the area that best addresses the public participation aspects of this work as referred to in
Section 130 of the Clean Air Act (1990) and discussed next.
2.7 EPA's PUBLIC PARTICIPATION PROCEDURES
EPA provides opportunities to participate in establishing, evaluating, and revising emission factors
through a public review process. These emission factors are made available for external review and comment
before publication. External reviewers include representatives of affected industries and trade associations,
state and local air pollution control agencies, and environmental groups. EPA has worked cooperatively with
trade associations to gather data in developing emission factors and plans to continue to do so.
EPA's published emission factors are intended to provide an affordable method of estimating
emissions, particularly to characterize total emissions of a large geographic area containing many individual
facilities. Therefore, these emission factors attempt to represent a typical or average facility or process in a
given industry. EPA recognizes that other methods of obtaining emission estimates may be more accurate
than industry-average emission factors, and it encourages the use of better methods whenever a source and/or
the state or local regulating authority is able to support those methods, which include continuous emission
monitoring, source testing, material balances, and engineering calculations.
Anyone with valid information is encouraged to submit data to establish new emission factors, revise
existing emission factors, or demonstrate unproved emissions estimating techniques. Information may be
submitted at any time, regardless of whether a subject source is currently addressed. The Agency encourages
all interested parties to take every opportunity to review emission factors and to provide information for
factor quality improvement. Specific details on participating in the public review of emission factors appears
in Public Participation Procedures for EPA's Emissions Estimation Guidance Materials, which appears in
Appendix B.
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CHAPTERS
UPDATE PROCEDURES AND INFORMATION FLOW
This chapter provides an overview of the process and the steps required to develop a new. or update an
existing, emission factor document (See Figure 3-1.) A more detailed discussion of how to accomplish these
steps is presented in Chapter 4.
3.1 PRELIMINARY DATA SCREENING
A preliminary screening of in-house Emission Factor and Inventory Group (EFIG) information is
conducted to determine if an new or update section is warranted. This screening may be triggered by the
reasons discussed in section 2.5. This screening involves assembling and reviewing all data in hand and
searching for additional available information. This task entails a review of all information in EFIG internal
files, including those for AP-42, the Locating and Estimating (L&E) documents, Source Test Information
Retrieval System (STIRS), Factor Information Retrieval System (FIRE) and EPA's Air Emissions Species
Data Base SPECIATE. Additional information may be available from EPA's Emission Standards Division,
the Office of Research and Development, trade associations, and other sources, as detailed in Section 4.3.
After review of this information, a decision is made by the EPA project leader on whether to proceed with the
section development or revision or to stop work.
3.2 ADDITIONAL DATA COLLECTION
Following a decision to proceed, a request is made to external organizations to review existing
information and to supply any additional data. This request is made to trade association(s) representing the
source categories covered, a focused list of state and local agencies and selected environmental interest
groups The industry associations and state and local agencies may be able to contribute process
descriptions, source emission tests, and additional information on emission controls.
3.3 DRAFTING DOCUMENTS
Following receipt of additional information, revision of an existing emission factor document or
development of a new document is begun. An internal draft is expected in about 6 months unless a
significant amount of new information is identified through industry or state and local agency contacts.
Existing text should be used if possible, with technical accuracy or editorial inadequacies improved where
needed. Extensive information describing the preparation process is given in Chapter 4 of this document.
If an AP-42 section is being drafted or updated, work on the background document discussing all
primary references, calculations, and other pertinent information (as well as the related files) is done
concurrently. The background document should identify all data, discuss their quality rating(s), and
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Chapter 3
Update Procedures and Information Flow
document all decisions on their use. Analyses and any statistical manipulations of the data should also be
clearly documented. The background document for a revised section should clearly indicate which emission
factors were deleted, revised, or added.
3.1 Preliminary Data Screening
No
.Step
Work
3.2 Data Collection
3 J Draft Revised Document,
Factors, and Background Information
i
3.4 Internal Review
3.5 External Review
I
3.6 Finalize Document and Factors
3.7 Update Distribution Mechanisms and Files
\
3.8 Errata Procedures
Figure 3-1. Overview of the emission factor document preparation process.
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Chapter 3 Update Procedures and Information Flow
3.4 INTERNAL REVIEW
All documents should be reviewed for clarity, technical accuracy, and thoroughness. The EPA project
leader's review should be completed in about 2 weeks and should be followed by distribution for internal
review by other relevant Agency personnel. This internal review should be completed in 30 days. The
project leader should collect and maintain all comments on this review draft and ensure that all comments are
addressed and incorporated within 30 days. After the project leader's review and approval that this draft is
technically satisfactory, it is then ready for external review. If the project leader cannot approve a revised
draft because of technical deficiencies, then additional drafts, revisions, and reviews may be necessary before
proceeding to external review.
3.5 EXTERNAL REVIEW
After internal review is complete, the document is now ready for external review. In general, anyone
who supplied technical data for the document is asked to review it. External reviewers should include
appropriate representatives of industry, state or local agencies, environmental organizations, and other
technical experts who will agree to provide comments.
For external review, the project leader should provide an electronic edition of the revised draft AP-42
section and the revised background document to the Clearinghouse for Inventories and Emission Factors
(CHIEF) Sysop for posting on the CHIEF Bulletin Board. The AP-42 electronic section should contain all
graphics and tables that are to be part of the paper version. The revised background document should include
any files used for the development of the section such as spreadsheets, results and statistical analyses and
data bases). A "caution" page should be included as the first page of each draft AP-42 section, emphasizing
the fact that this is draft information that is subject to change, and should not be cited, quoted, or used for
regulatory purposes. The external review draft is posted only for the purposes of soliciting comments,
corrections, and additional data. External review is projected to take about 45 days unless additional review
time is approved by the project leader. When significant or extensive changes are made in response to review
comments, further review(s) of additional drafts may be necessary and would be accompanied by the
appropriate CHIEF Bulletin Board notices.
3.6 FlNALIZATION OF DOCUMENT
All external review comments should be sent to the EPA project leader for review and resolution. All
revisions necessary to address technical comments should be approved by the EPA
project leader. After the approved revisions are incorporated, the final draft document should be reviewed by
the EPA project leader to ensure satisfactory resolution and incorporation of all technical comments. Any
editorial corrections should be made at this point and the draft is then considered final and ready for
distribution. The EPA project leader should produce a final master paper copy from the electronic files in
order to ensure that all distributed versions will be consistent and to ensure that the electronic file is complete
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Ch«pter3 Update Procedures and Information Flow
and usable. The EPA project leader is the responsible authority for distribution of the completed document.
3.7 DISTRIBUTION MECHANISMS
The EPA project leader authorizes final distribution of the document by submitting the electronic file
to the CHIEF Sysop and a paper copy, generated from this file, to Info CHIEF for placement on Fax CHIEF.
The electronic file will be posted on the CHIEF BBS and will be used for the periodic update of the Air
CHIEF CD-ROM and for the publication copy of the next AP-42 supplement.
It is extremely important that all electronic and paper versions of the AP-42 sections agree.
Distribution procedures are to be strictly followed to ensure this. L&E documents are ready for publication
and distribution when completed and have no annual update cycle like the AP-42; except possibly the updates
on the Air CHIEF CD-ROM.
Upon receiving the final, approved electronic file(s) from the project leader, the CHIEF Sysop then
notifies the individual(s) responsible for both the Air CHIEF CD-ROM and paper supplements to AP-42 that
these updates are complete and ready for updating of the electronic and paper media. The Sysop is
responsible for copying the final electronic file of an AP-42 section onto the writable disks that have been
specially designated for only final, approved versions of AP-42 sections. The Air CHIEF CD-ROM is used
as the archival copy of all the sections of AP-42. The Sysop will maintain master files between printings of
the Air CHIEF CD-ROM.
3.7.1 Hard Copy
Individual new or revised AP-42 sections will be held for publication together as a supplement to the
Fifth Edition L&E documents will be printed and made available as they are ready.
Because all items within emission factor documents are to be prepared and made available
electronically, including graphics, the hard-copy outputs of the electronic files should be of good quality and
satisfactory as camera-ready copy suitable for a printing master.
3.7.2 Fax CHIEF
Fax CHIEF is a fax-on-demand service containing the printed version of all final AP-42 sections,
(but not L&E's). A separate document is maintained on the Fax CHIEF listing all AP-42 sections changed
since the last publication of an edition or supplement. Fax CHIEF can be accessed at (919) 541-5626 or
541-0548.
3.7.3 CHIEF Bulletin Board System (BBS)
The CHIEF BBS is an electronic repository of the most up-to-date information on inventories and
emission factors, including AP-42 sections, L&E documents, and FIRE. It is accessible on the OAQPS
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Chapter 3 Update Procedures and Information Flow
Technology Transfer Network (TTN), phone number (919) 541-5742.
The CHIEF BBS contains electronic files of the most current versions of final emission factor
documents. A separate Errata File (see Section 3.8) is also maintained on the CHIEF BBS. Historical or
archival copies of both AP-42 and L&E electronic files will not be maintained on the CHIEF BBS.
For final AP-42 sections, the CHIEF BBS will also be the repository for the electronic files of
background information to support the assignment of emission factors and ratings. The background file shall
contain the following electronic files:
• The full text of the background document;
• All spreadsheet and data base files used in the development or documentation of information
contained in the AP-42 section or background document;
• Graphics files in the native format of the software used to generate those files and any
exported format that was necessary to enable retrieval into WordPerfect® Version 6.1 for
Windows, and that were used in the AP-42 section contained on the CHIEF BBS or the
background document; and
• Any other electronic file designated by the EPA project leader as germane for documentation
purposes.
3.7.4 FIRE
The FIRE data base contains emission factors from final, not draft, AP-42 sections and L&E
documents that are available at the time of the annual FIRE update. The FIRE project leader is responsible
for incorporating any new or revised emission factors from new or updated AP-42 sections or L&E
documents into FIRE.
3.7.5 Air CHIEF CD-ROM
The Air CHIEF CD-ROM contains the most recent electronic version of final emission factor
documents as of the cutoff date for CD-ROM production. The Air CHIEF CD-ROM will serve as the
archival copy of the electronic version of AP-42 sections and L&E documents as new or revised editions are
prepared.
3.8 ERRATA PROCEDURES
In the event that errors are detected in a final AP-42 section a notation will be added to the errata file
available on the CHIEF BBS. The electronic file should be corrected and the correct
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Chapter 3 __ Update Procedures and Information Flow
version should replace the erroneous version immediately on the CHIEF BBS. The next printed supplement
must also contain the corrected copy.
The project leader is responsible for any necessary changes, including updating document footer
dates, and preparing notices to be posted on the CHIEF BBS and Fax CHIEF, and The CHIEF Newsletter, if
deemed necessary. The project leader will notify the CHIEF Sysop of what material on the CHIEF BBS must
be revised and will provide the corrected electronic file for the section, in addition to an Errata File notice to
be posted on the CHIEF BBS. The project leader will also submit the corrected paper version to update Fax
CHIEF. The project leader is responsible for the same reviews for consistency between the electronic and
paper versions as in a full, regular update. The project leader must also prepare a memo to be attached to the
paper and electronic copies of the background document to record any such revisions.
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CHAPTER 4
FACTOR DEVELOPMENT AND PRESENTATION DETAILS
This chapter is intended as a compilation of procedures to be used as a guide for the individuals who
prepare or revise emission factor documents to be published as AP-42 sections or Locating and Estimating
(L&E) documents. Such new or revised emission factor documents are continually being prepared.
Following a standard technical and editorial approach to preparing and revising, these documents will
maintain internal consistency within each document and will help to make the-infonnation presented in both
document series more consistent in format. Since the procedures for AP-42 and the L&E documents are
similar, they will be discussed on the same basis hereafter except where specific differences need to be noted.
Format and style specifications for both AP-42 and L&E documents appear in Appendix A and
should be reviewed early in the course of preparing a new or revised AP-42 section or L&E document, by
both the prospective-author and the clerical staff who will produce the final section.
Because the AP-42 and L&E document series contain 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 document format and electronic publishing requirements.
4. l CONTENT AND FORMAT OF A TYPICAL AP-42 SECTION
The typical AP-42 section consists of the following elements:
• General process description, with flow diagram(s) indicating emission points and
pollutants,
• Discussion of emissions and any applicable or typical control devices
• Table of emission factors and/or equations for calculating emission factors
• Dated listing of changes since last revision
• 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 section. The text and flow diagrams explain and
qualify the tabulated emission factor data. While the text provides general information on the process and
pollutants, users often turn first to the tables to obtain the emission factors. If the tabular information is not
clear, the user may then consult the diagram or the text and, if need be, the references. The emission factor
table should provide the user with emission factors for a source and should give the user all the information
needed to apply the emission factors 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 about any
qualifications placed on the emission factors. The most important part of an AP-42 section, therefore, is its
emission factor table(s), which must be able to stand alone in terms of clear technical content for use by the
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Chanter 4 Factor Development and Presentation Details
reasonably well-informed user. The less well informed user is expected to familiarize themselves by reading
the text describing the process, sources of emissions and controls employed. A principal point to keep in
mind in table preparation is to report emission factors for as many different subcategories within the source
activity as reasonably possible. Source Classification Codes (SCCs) should be included in the tables for each
emission source.
Footnotes to tables should be provided to explain any and all qualification of emission factors and
conversions. These notes may be as brief as a recommendation to read the text before applying a particular
emission factor, or as lengthy as necessary to assist with correct emission 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. The same terminology should be used in the table and the 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. Detailed process schematics are
preferred, instead of simple block diagrams, if they do not detract from the primary purpose of comple-
menting the emission factor table. However, be aware that all schematics and diagrams must be in a certain
format, as discussed later, in order to be compatible with the electronic distribution of the final documents..
The process description text explains the flow diagram and gives a general idea of the process. It is
not intended to give a complete description of the industry, and 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.
The references for an AP-42 or L&E section can be extremely important to a user who wishes to
apply an emission factor to a specific source. Although emission factors do not apply to specific sources with
absolute accuracy, the additional process characterization and other information found in the references may
enable a user to more accurately estimate emissions. 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 identify the reference clearly, and provide the reader with sufficient information to obtain a copy.
The single, most important point about the format of any emission factor document is that all
elements including, but not limited to, text, tables, figures, diagrams, and reference lists, must be prepared
electronically, and the final version must be suitable as a camera-ready master for printing and electronic
distribution. The Emission Factor and Inventory Group (EF1G) has designated that the word processing
software, WordPerfect* for Windows, be used for all emission factor documents. (Currently, Version 6.1 is
recommended.) Any graphic drawings or figures should be prepared in a software, such as Freelance* for
Windows, that is compatible for producing a camera-ready master without significant additional effort.
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Chapter 4 Factor Development and Presentation Details
4.2 CONTENT AND FORMAT OF A TYPICAL L&E DOCUMENT
The major purposes of L&E documents are to identify the significant sources of the pollutant of
interest and to identify techniques for estimating emissions for these sources. Each L&E document typically
begins with an executive summary listing an overview of the primary categories of emissions. This summary
should include a table presenting the national emission estimates developed^for the predominant categories
emitting the pollutant Due to the evolving nature of toxic air pollutant programs, it is often difficult to
develop supportable national emission estimates for all source categories. As new information is developed,
the magnitude of the national total emissions will be adjusted as well as the relative rankings of source
categories.
The first section, usually entitled "Purpose of Document," states general information about the series
of L&E documents and contains a current list of pollutants for which published L&E documents exist and
their EPA publication numbers. The remainder of Section 1.0 provides details on any relevant standards,
their history and their current status, issued by EPA or possibly other agencies, such as the Occupational
Safety and Health Administration (OSHA) or the U.S. Consumer Product Safety Commission, and which
may affect emissions of the pollutant of interest. This section concludes with paragraphs advising readers
about how to best use the document, cautions about the data, and opportunities for document review and
comment as well as providing additional data.
The second section begins with an overview of the entire document, which briefly outlines the main
focus of each subsequent section and any appendices. The remainder of Section 2.0 describes the ratings
assigned to emission factors and the criteria for assigning these ratings, and also describes the criteria for data
quality- ratings for source tests from which the emission factors were derived. Chemical and physical property
data are typically included in Section 3.0.
The remaining sections may vary and will be structured according to the types of sources and
processes that emit the pollutant being addressed. Information such as how the substance is created or
prepared for use, or any manufacturing operations in which it is used are discussed. Like AP-42, L&E
sections include process flow diagrams, discussion of emissions and controls, and emission factor table(s).
Where appropriate, it is acceptable to use the process descriptions from other L&E or AP-42 sections.
The last section in an L&E document prior to the references describes typical sampling and analytical
methods for the pollutant in question. The last text section usually lists the references used to prepare the
L&E document.
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Chapter 4 Factor Development and Presentation Details
Required appendices include one in which methods for estimating the national emissions are
described, and another containing a summary table of all emission factors (by SCC) presented in the L&E
document Details regarding format for L&E documents can be found in Appendix A.
4.3 DATA COLLECTION
The first step in characterizing sources and pollutants for emission factor documents involves a
search for and collection of available emissions information associated with the sources or pollutants of
interest. The purpose of this effort is to gather current information that can be used to write process
descriptions, identify facilities, pollutants, and emission points, and develop emission factors and emission
estimates. This information search should include the following sources: (1) current AP-42 background
files; (2) technical papers (e.g., trade journals, conference reports); (3) emission factor data bases and bulletin
boards; (4) EPA and other federal agency contacts; (5) State and local agency contacts; and (6) industry
contacts and trade associations.
4.3.1 AP-42 Background Files
The AP-42 background files are the beginning point for any AP-42 section update effort and should
be reviewed for any section being updated. The file contains the background document for the existing
section, copies of emission test reports used to establish the emission factors, copies of other emission test
reports cited in the background report, as well as copies of other references. The file may also contain recent
information or test reports accumulated by various EPA personnel.
4.3.2 Literature Search
A search of technical papers for source test and background information should be conducted for the
emission source category or pollutants in question. This search can be conducted by EPA library services.
The request for a search from Agency library services should be made directly through the EPA project
leader It should be noted, however, that the EPA search may be limited and may need to be supplemented by
additional external searches.
The following references and documents are examples of sources of information that should be
reviewed. The project leader should develop a list of the best places to look.
• Background Information Documents (BIDs) for New Source Performance Standards
(NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAP) or
Maximum Achievable Control Technology (MACT) standards;
• Locating and Estimating (L&E) documents;
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Chapter 4 Factor Development and Presentation Details
• Control Techniques Guidelines (CTG) documents:
• Control Technology Center (CTC) and EPA's Office of Research and Development
documents;
• References in the National Technical Information Service (NTIS);
• References in the Compendex Plus computerized data file in DIALOG, a computerized
bibliographic utility;
• Kirk-Othmer Encyclopedia of Chemical Technology (for process information);
• Mannsville Chemical Products Synopsis;
• SRI Directory of Chemical Producers;
• Chemical Marketing Reporter: Chemical Profiles;
• Technical Trade Associations;
• AWMA's Engineering Manual and Journal Articles;
• University libraries;
• Emission factor reports produced by States or local agencies or Europe and elsewhere;
• Information in AP-42 background files pending review;
• Factor Information REtrieval System (FIRE) data base; and
• State data bases, permit files, and source tests.
• BACT analysis
4.3.3 Emission Factor Data Bases
The following data bases and bulletin boards are sources of emission factors and supporting data. A
search of these data bases early in the data collection process can identify data leads and possible sources of
information to characterize a particular industry.
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• EPA's Factor Information Retrieval (FIRE) System - a consolidation of criteria and HAP
emission factors from the AP-42 Fifth Edition, L&E documents, state source test reports, and
Aerometric Information Retrieval System (AIRS)-Facility Subsystem (AFS);
• VOC/PM Speciation data base Management System (SPECIATE) - clearinghouse for
speciation profiles (not emission factors) for VOCs and PM used primarily for atmospheric
modeling;
• Toxic Release Inventory (TRI) data base. Most useful for preparing L&E documents, but it
can also help in identifying facilities related to an AP-42 section and it may identify
additional toxics being emitted by those facilities;
• National Air Toxics Information Clearinghouse (NATICH) data base;
• Source Test Information Retrieval System (STIRS) - A databse of stack test reports collected
from states by the EPA and stored electonically on CD-ROM disks.
• The emissions estimation code in the AIRS data base may identify which States have
developed their own emission factor or rely on individual source tests to estimate emissions
for the category of interest; and
• Source Characterization Group source test files, including the Test Method Storage and
Retrieval (TSAR) data base.
4.3.4 EPA and Other Federal Agency Contacts
Various EPA offices and other Federal Agencies may also be able to provide information
characterizing emissions and should be contacted. Potential sources of information include EPA's Emission
Standards Division (ESD), EPA research laboratories, the Department of Energy, the Department of Defense,
and the Department of Agriculture.
The ESD of OAQPS is responsible for developing and promulgating regulations for stationary
sources of air pollutants, hi doing this, ESD produces numerous source test reports, background information
documents, and other useful technical reports. ESD reports should be reviewed for data on the industry in
question. In addition, EFIG, the CTC, and the EPA's Air Quality Strategies and Standards Division should
be contacted for information that may be pertinent to emissions document development.
Other parts of the Agency, such as the Acid Rain Division of EPA's Office of Air and Radiation, and
Climate Change Division of the Office of Policy Planning and Evaluation should be contacted by the project
leader in seeking information on a source category.
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The EPA laboratories that might provide useful data include the Risk Reduction Engineering
Laboratory (RREL) in Cincinnati, the Air Pollution Prevention and Control Division (APPCD) and the
National Exposure Research Laboratory (formerly AREAL) in Research Triangle Park (RTP). NC. These
laboratories are generally more research oriented than OAQPS, and often develop and report emission data
that are usable in emission factor documents.
The EPA 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 is concentrated in a particular Region. Examples would be anthracite coal in Region III. sulfite
paper mills in Regions I and X, and bagasse-fired boilers in Regions IV and IX.
Initial requests should be specific. It is helpful to find personnel who have visited the sources being
studied and who can offer valuable detailed information on equipment configurations, control devices,
emissions, etc., that may not be otherwise available. Avoid recontacting and recollecting the same data
already solicited and incorporated into STIRS and other data bases. The project leader should also make the
initial contact to other Federal Agencies.
4.3.5 State and Local Agency Contacts
State and local agencies are contacted if a source category is concentrated in certain states, with
initial contact made by the project leader. As with the EPA Regions, it is desirable to contact someone who
has visited the source types of concern. The Federal Report Act dictates that no more than nine state agencies
or pnvate entities may be contacted by EPA or EPA contractors with the same request without an information
request approved by the Office of Management and Budget. State agency contacts may be obtained through
the respective EPA Regional Offices or STAPPA/ALAPCO. to order to avoid redundancy, make all requests
in the context of work already done.
4.3.6 Industry Contacts and Trade Associations
Companies may be contacted to obtain copies of test reports and process information. To select
which companies to contact, a list of plants can be compiled from current directories and the companies with
the most plants can then be identified. By contacting the headquarters of such companies, requests can be
centralized and coordinated and information can be collected on a large number of plants and pollutants. In
cases where contacting the major companies would not provide sufficient information, additional companies
may be identified.
Occasionally, affected trade associations possess current process information, including successful
process modifications, control devices, etc, that may be helpful in developing a section. Whenever possible,
these associations should be consulted, especially for comments on the draft version of a section or document.
The EFIG maintains a computerized list of potential and past contacts, by section, and their phone numbers
and addresses that should be used as a starting point when contacting these associations. Due to the dynamic
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nature of individuals and organizations, this information is often dated and must be augmented by direct
contact with individuals to ensure currency of information, hi addition, many relevant trade association are
listed in the National Trade and Professional Associations of the United States directory.
4.4 DATA EVALUATION AND ANALYSIS
After the data have been collected, the next step is to review and analyze the data to determine which
data should be used for the development of emission factors and how that data should be grouped. The
analyst must evaluate the validity of individual emission source assessments (source tests, mass balances,
etc), how well the tested sources represent the source category as a whole, and whether subdividing the source
category is warranted. The results of each assessment must have a data quality rating assigned. A clearly
written summary of all data evaluated, any necessary assumptions that were made, and all decisions reached
are incorporated into the background report. Both the data that is excluded from eventual use in any emission
factor and the data that are used should be described in a concise manner.
4.4.1 Evaluation of Primary and Secondary Data
Emission factors in AP-42 sections and L&E documents are typically based on data obtained from a
variety of sources including, but not limited to, published technical papers and reports, documented emission
test results, and personal communication. The data obtained 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.
Source test reports should be reviewed and summarized for at least the items listed below. The
reviewer should also make note of any other items about the facility, test method, or the test report that might
have affected the total emissions or the emissions per thruput unit.
• process, feedstock, or fuel type
• plant capacity and operating rate during the test
• control devices and their operating parameters
• the age of the facility and the control devices
• any process or control device upsets during the test
• the pollutants tested for and the test methods used
• any deficiencies and/or deviations in the test procedures
• the number and duration of test runs
• the representativeness of the source tested within its industry
• the completeness of QA/QC documentation
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Two EPA publications may be used to assist the reviewer in examining source test reports.
Guidebook: Preparation and Review of Emission Test Reports, and 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, qualm
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 (EMTIC) on the OAQPS TTN electronic bulletin board, dial up access, (919) 541-5742; internet
access http://ttnwww.rtpnc.epa.gov. The reviewer should also be familiar with the EPA reference test
methods as well as the pollutant definitions and conventions used in the AP-42 and L&E documents, and with
some of the difficulties in deriving emission factors for the pollutants of interest from the available source
tests. Section 2.4 describes the pollutant terminology preferred for emission factors and how the available
test methods relate to those pollutants.
In reviewing source test reports, the following general criteria can be used to avoid analyzing
excessive amounts of data and to ensure that proper data are used in updating emissions documents.
• Emissions data should be obtained from a primary source (i.e., test reports) whenever
possible. It is necessary to assess the primary references in order to develop accurate data
quality ratings and to ensure that valid assumptions and procedures were followed in
calculating the facility's emission rates. Report summaries should not be used, unless no
other primary source is available.
• If sufficient data exist, focus efforts on test reports for those technologies and emission
controls that are most commonly used in the industry. Processes and controls at some
industries change periodically due to market trends, improvements in production efficiency or
product quality and pressures to reduce pollution. Test reports that are less than 10 years old
are more likely to be representative of the most common technologies and emission controls.
However, this may vary depending on the specific industry, so some knowledge of changes in
the industry is necessary in deciding how best to use older data. Although efforts should
focus on current technologies, information on older technologies is of value for the purpose of
tracking historical trends in emissions.
• Source tests where more than one test run was performed at each site are preferred.
• Test reports should contain sufficient detail to evaluate both the testing procedures (e.g.,
sampling methodologies and test methods used) and the source's operating conditions (e.g.,
charge rate or thruput data).
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• Source test data should normally be used only if the data were obtained under conditions that
are representative of operating conditions typically encountered at the source in question.
• The following data are usually excluded from further consideration:
Test series reported in units that cannot be converted to the selected reporting units
using reasonable assumptions that will not significantly increase the uncertainty of the
emissions rate;
Test series in which the process or emission source or control device is not clearly
identified and described; and
Test series in which it is not clear whether the emissions measured were controlled or
uncontrolled, or if other emission sources may have contributed to the measurements.
If actual production data for the time period of the test series are not available, production rates for
periods of similar operations or an annual average production rate can be used. If such alternative production
rate data are used, an attempt should be made to confirm and document that the facility was operating near
the alternative production rate. Note that the data quality rating should be reduced if actual production rates
for the test period are not available and surrogate methods for determining production are not reliable or are
not documented.
For fuel combustion sources, the F-factor method can also be used to determine emission factors
from stack concentration data when fuel thruput rates are not available. This method relies on the fact that
the CO: concentration in the stack can be closely correlated to the heat input rate. The heat content of a fuel
is closely related to its carbon content and almost all carbon is converted to CO2 in an efficient combustor.
The F-factor for a specific fuel or fuel type allows a pollutant concentration to be expressed as an emission
factor in units of pounds per British Thermal Unit (BTU). For most fuels a conversion to pounds per weight
or volume of fuel combusted can be made, if desired, by using an average heat content for the fuel. Appendix
C contains a detailed description of how to use the F-factors.
There are also situations where thruput data are not necessary or even desirable for use in an
emission factor. The pollutant concentration by itself may be the best way to express an emission factor for
the outlet of many control devices and air conveying systems. In such a case, the air flow from the device
becomes the thruput.
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4.4.2 Assign Data Quality Ratings
After reviewing the test reports, it should be possible to assign a data quality rating to the emission
data for each pollutant test series. The data quality ratings for the individual tests are not to be confused
with the overall emission factor ratings. The data quahty ratings are an appraisal of the reliability of the
emissions data that will be used later to develop the emission factor. The emission factor rating is an
appraisal of the ability of the overall average factor to represent a national annual average emission rate for
the source category. Emission factor rating determinations are discussed in Section 4.6.8.
Test data quality is rated A through D, based on the following criteria:
A - tests are performed by using an EPA reference test method, or when not applicable, a sound
methodology. Tests are reported in enough detail for adequate validation, and, raw data are
provided that can be used to duplicate the emission results presented in the report.
B - Tests are performed by a generally sound methodology, but lacking enough detail for
adequate validation. Data are insufficient to completely duplicate the emission result
presented in the report.
C - Tests are based on an unproven or new methodology, or are lacking a significant amount of
background information.
D - Tests are based on a generally unacceptable method, but the method may provide an order-of-
magnitude value for the source.
The quality rating of test data helps identify good data, even when it is not possible to extract a
emission factor representative of a typical source in the category from those data. For example, the data from
a given test may be good enough for a data quality rating of "A," but the test may be for a unique feed
material, or the production specifications may be either more or less stringent than at the typical facility.
In following the general guidelines discussed above, four specific criteria can be considered to
evaluate the emission data to ensure that the data are based on a sound methodology, and documentation
provides adequate detail. A test series is initially rated A through D in each of the following four areas.
• Source operation. If the manner in which the source was operated is well documented in the
report, and the source was operating within typical parameters during the test, an A rating
should be assigned. If the report stated parameters were typical, but lacked detailed
information, a B rating is assigned. If there is reason to believe operation was not typical, a C
or D rating is assigned.
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• Test method and sampling procedures. In developing ratings, the estimated accuracy and
precision of the test method as well as the adequacy of the documentation are considered. In
general, if a current EPA reference test method, appropriate for the source, was followed, the
rating should be higher (A or B). If other methods are used, an assessment is made of their
validity. If it is judged that the method was likely to be inaccurate or biased, a lower rating (C
or D) is given. A complete report should indicate whether any procedures deviated from
standard methods and explain any deviations. If deviations were reported, an evaluation is
made of whether these were likely to influence the test results.
• Process information. During testing, many variations I the process can occur without warning
and sometimes without being noticed. Such variations can induce wide deviations in
sampling results. If a large variation between test run results cannot be explained by
information contained in the site test report or from test reports of other sources, the data are
suspect and are given a lower rating or excluded. However, it should be recognized that a
process may have highly variable emissions and a lower rating may not be appropriate solely
on the basis of wide deviations in sampling results.
• Analysis and calculations. Ideally, test reports should contain original raw data sheets and
other documentation such as, gas parameters (dscfin, 02%), calculation sheets, or example
calculations describing how the calculated emission results were obtained. If there are data
sheets, the nomenclature and equations used are compared with those specified by EPA to
establish equivalency. The depth of review of the calculations is dictated by the reviewers'
confidence in the ability and conscientiousness of the tester, based on such factors as
consistency of results and completeness of other areas of the test report. Reports may
indicate that raw data sheets were available but were not included. If the test report is of high
quality based on the other criteria, the quality rating should not be lowered due to a lack of
data sheets.
An overall emission data quality rating is developed considering the scores on the four criteria.
There is no single equation or method for the relative weighting of the factors, because each report presents
different issues, and the rating system needs to allow the flexibility to consider the strengths and weaknesses
of each test series individually and reach a judgment on the overall rating. The two criteria, (1) the test
method and sampling procedures and (2) the process information, should be weighted heavily when reaching
this judgement. If either of these two criteria are assigned a low rating, this low rating should be assigned as
the overall data quality rating, no matter how complete the other documentation. Because ratings are
somewhat subjective, detailed comments describing the rationale for assigning the overall test report rating
should be included in the background documentation. The rationale should be explained regardless if there
are discrepancies in the tests.
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After assigning a preliminary emission data quality rating based on the four criteria, the quality of the
production data is considered. Production data quality can affect the emission data quality rating. General
guidelines for maintaining or reducing the preliminary data quality rating are described below. The emission
data rating may be lowered by as many as three quality levels. However, if the emission data qualm is
already low (e.g., had a C rating) the lowest rating that can be assigned to the final data is a D. This approach
is reasonable because the D rating reflects data that may be in error by an order of magnitude and it is
unlikely that production data would affect this significantly. The alternative approach is to exclude the data
from use in developing emission factors. The guidelines for reviewing production data and assigning final
data quality ratings are the following:
• Do not change preliminary emission data quality rating if production was measured during the
test series or during the testing period. (If measured during the testing period but not during
the test series, it can reasonably be assumed that the facility continued to operate at the same
rate throughout the test period.)
• Reduce quality rating to one level below preliminary emission data rating if production was
measured during a different period other than the test period and it can reasonably be
assumed that the facility was operated at a similar rate during both periods.
• Reduce quality rating to two levels below preliminary emission data rating if the production
data presented in the report is an estimate based an annual production or capacity and the
number of hours of operation annually.
• Reduce quality rating to a D rating if production data are based on annual capacity or annual
production data, and it is necessary to use assumptions that can not be confirmed in
estimating the production rate at the time of the emission test.
4.5 GROUP THE EMISSION DATA
After the individual data points have been reviewed and rated, the data must be grouped into related
clusters for which the average emission factors will be developed. It may be straightforward to group the data
for industries where similar processes are used by most of the facilities tested, but it is more likely that
considerable review and evaluation of the data will be required to group some of the emission points in the
source category. The developer should use an understanding of the processes used by the industry and a
consideration of the parameters that might significantly affect the emissions to group similar data together.
Statistical techniques may be used to refine the initial groupings where there are sufficient data. Examples of
some of the criteria to be considered when grouping the data are given below.
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• Source Category. Among the test data for the specific source category under review there
may be some test data for generic emission sources, such as combustion sources. If the
combustion gases do not contact the industry's process material and there is no reason to
believe that the combustion equipment used is peculiar to the industry, then the combustion
data might be better grouped with a potentially larger data base for combustors in all
industries.
• Process Type. In most cases, data from two or more distinct processes used to produce the
same product, such as wet and dry processes for cement manufacturing, should be put in
separate groups.
.^
• Representativeness of Source. Data from some sources may be considered for a separate
grouping based on the facility's size or age. However, such a separation should be verified by
a comparison of the data sets as well as consideration of why the size or age of the facility
might affect emissions.
• Emission Source. Emission data for primary crushers should not be grouped with emission
data from downstream size reduction equipment; smelting furnace emissions should not be
grouped with refining furnaces.
• Equipment Design. Direct-fired versus indirect-fired heaters, countercurrent versus parallel
flow dryers.
• Operating Conditions. Dryer temperatures, moisture start and end points, batch versus
continuous operations, wet scrubber pressure drop, also affect emissions data grouping.
• Raw Material or Fuel Characteristics. Moisture content, sulfur content, hardness, and type of
fuel should be considered when grouping emission data. Emission data from different fuel
types are not grouped together.
• Control Devices. Do not group emissions data from different control devices together, except
where the pollutant emissions are not expected to be affected by those devices. (But note that
the comparison of controlled to uncontrolled for the same test series may be extremely
useful.) Also note that emissions of some pollutants should be grouped with "uncontrolled"
data even though they were measured downstream of a device which controlled other
pollutants, such as NOX or CO after a baghouse.
• Test Method Used. The test method used defines what pollutant was actually measured. For
example, do not group Method 25 (NMOC) data with Method 25A (TOC) data unless it can
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be assumed that the compounds which are not detected by either method are not likely
present Also, a test method may produce different results if run at differing stack
temperatures.
The discussion in the next section on handling of data outliers may also be of use in determining if a
data point is non-representative due to some of the criteria given above. All data found should be rated.
grouped and identified in the background document. A clear description of what data were grouped together
and why should be provided in the background document Any data which could not be rated or grouped
should also be identified in the background document
4.6 DEVELOP CANDIDATE EMISSION FACTORS AND DRAFT SECTION
After the emissions data have been grouped, the author develops the candidate emission factors that
represent each process or grouping. This process may involve eliminating some data from further
consideration or converting some data to a different format in order to allow for averaging. It may also
involve adjusting some of the grouping choices made earlier, depending on the quantity or quality of data
available. In this regard, the author should keep in mind that the goal is not to calculate and present a number
of unrelated averages, but to present an internally consistent representation of emission factors, especially
when those factors are related. For example, PM-10 emission factors should always be less than or equal to
total paniculate emission factors, and controlled emission factors should always be less than uncontrolled
emission factors. As always, any decisions on how or if any data were used should be clearly documented in
the background report. The purpose of this section is not to present a statistical treatise, but merely to
describe the conventions and preferences which have been used in developing emission factors. Deviations
from these practices are allowable as dictated by the specific situation.
4.6.1 Averaging of Data
An emission factor should represent the expected emissions from a collection of emission sources of
a similar type It can be based on emission source testing, material balance, or engineering analysis, and it
can be presented as a simple average or mean, or as a formula which accounts for the significant parameters
affecting emissions. The presentation may include additional information on ranges, confidence intervals,
and other measures of uncertainty or variability, depending upon the extent of data available. The arithmetic
mean is usually used for emission factor development and is the preferred method unless there are strong
reasons to use an alternative method.
Before grouping emission factors to develop an average factor for a source category, a single average
emission rate for each single source should be determined. Therefore, the results of individual test runs on a
given source are reduced to a single emission factor for that source using the arithmetic mean. That means, if
multiple tests of the same source are available, they are combined into a single emission factor to represent
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that source. The average emission factor for the source category is then determined by computing the
arithmetic mean of the single emission factors for each source tested In this way, an emission factor from
one facility does not disproportionately affect the average emission factor for the source category.
hi some cases, the data available may exhibit characteristics suggesting that a geometric mean is a
more appropriate for developing the average emission factor for a source category. Also, there are cases
where the median emission factors may be more representative of typical emissions. The rationale for
utilizing a geometric mean or median, instead of the arithmetic mean, should be decided with the project
leader and the rationale should be documented in the background report. An explanatory footnote should also
be added to the emission factor table indicating the method used to develop the emission factor if it was not
an arithmetic mean.
Emission factors should be represented as a single value whenever possible, or as a formula where
significant effects of other parameters can be quantified. If a formula is presented, it is good practice to also
include example calculations of emission factors using the formula, and typical ranges or default values for
the variables. An indication of the variability, such as a range of values, may accompany an emission factor
if it will contribute to an understanding of the scatter of the data. Any insights into how the range can be
further sub-categorized or explained should be included. If necessary and supportable by the data, the author
can break the emission source into smaller sub-source types based on age, size, operating temperatures or
other parameters, and present separate emission factors rather than ranges for each sub-type.
Confidence intervals can be used to provide valuable information on the uncertainty and variability
of emission factor data. However, rarely are there sufficient data to allow valid confidence intervals to be
generated Prudent application of statistical procedures precludes the development and presentation of
confidence intervals in emission factor documents 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., the source is
operating at typical conditions); and
• the measurement method was properly applied at each source tested.
When developing an emission factor, the author should always be sensitive to situations where data
are sufficient (probably only when there are about 10 or more data points and they are predominantly rated A
or B) for such intervals to be meaningful and valid. When sufficient data are available to develop confidence
intervals, the author should provide the resulting confidence interval information in the background document
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and the AP-42 section or L&E document. Documentation such as data plots (histograms) may be included
with the background information if desired.
4.6.2 Combining Tests of Different Quality Ratings
In the emission data review process, individual source tests were each given a data quality rating of A
to D (Section 4.4.2 above). In developing the average emission factors from these rated source tests, the
author should attempt to develop the most reliable factor by using only the most reliable tests, hi the ideal
situation, a large number of A-rated source tests for typical sources 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 rarely possible due to the shortage of A-rated data. If the number of A-rated
tests is such that the inclusion of B-rated tests would increase the confidence of the emission factor, then B-
rated test data are included in the calculation of the average emission factor. It is also possible to include C-
or even D-rated test data with the A- and B-rated data in some situations. This should only be done where the
number of A- and B-rated tests is so small that the representativeness of those tests is suspect and where the
author has determined that the lower-rated tests do not appear to be biased versus the better documented and
higher-rated tests. In such a case the inclusion of more tests, even of a lower quality, is warranted because it
increases the confidence that the average is representative of the source category as a whole. Unrated ("U")
test data are used only when no better data are available, and should not be combined with any rated test data.
4.6.3 Controlled Emission Factors
An effort should be made to obtain and present data for both uncontrolled and controlled emissions
in emission estimation documents. Emission factors should be clearly identified as uncontrolled or controlled
by a specific control device, either in the table heading or in individual entries in the table. For example,
"fabric filter" is a specific control device, while "PM control" is not. One method of showing both controlled
and uncontrolled emission factors in a table is to give the process name with its Source Classification Code
(SCC) on one line and use indented lines underneath this overall process name to indicate the uncontrolled
scenario and each controlled scenario by specifying the control device. (See example AP-42 section in
Appendix A.)
If a device that limits or reduces product loss (emissions) is an integral part of a process; the
emissions from the process should not be labeled "controlled". However, the emission factor table and the
text should describe the standard process equipment in use. Example of such devices are cyclones used to
separate products from air in pneumatic conveying systems, cyclones used to recover catalyst in petroleum
catalytic crackers, and chillers added to degreasers in order to reduce solvent loss.
The text should present information on applicable control techniques and should reference Control
Techniques Guidelines (CTG), Alternative Control Techniques (ACT), New Source Performance Standards
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(NSPS) Background Information Documents, or other documents that contain details on application of these
techniques to the source category. The text should also note if there is a probability of rapid developments in
control technology which may alter any typical control efficiencies mentioned in the text.
The information presented should enable the user to estimate both controlled and uncontrolled
emissions wherever possible. This may be accomplished by either presenting both the controlled and
uncontrolled emission factors, or by presenting only one factor (either controlled or uncontrolled) and
providing a default control efficiency. The author should exercise caution and judgement in deciding how to
determine and present emission factors and control efficiencies. If both controlled and uncontrolled emission
factors are presented, the control efficiency implied by the ratio of the controlled to the uncontrolled source
emissions should be reviewed to determine the plausibility of the implied control efficiency. Alternatively,
the average control efficiency can be determined and shown explicitly, rather than a controlled emission
factor, in cases where tests are available for both pre- and post-control situations on the same sources. Also,
the preparer should verify that the process conditions for both controlled and uncontrolled emissions data are
comparable.
A limited discussion of the typical range of control efficiencies and the parameters affecting the
implied or default emission factor should be included in the Section if the information is available. Note that
this discussion of the control efficiencies is generally not necessary for straight-forward applications of
traditional control devices.
A basic description of the techniques typically used by industry to control PM/PM-10, VOCs, S02,
NOX. CO and HAPs can be found in the following EPA documents:
Control Techniques for Particulate Emissions from Stationary Sources - Volume /,
EPA 450/3-8l-005a, September 1982
Control Techniques for Particulate Emissions from Stationary Sources- Volume 2,
EPA 450/3-8l-005b, September 1982
Control Techniques for Sulfur Oxide Emissions from Stationary Sources, EPA 450/3-81 -004,
April 1981
Control Techniques for Carbon Monoxide Emissions from Stationary Sources,
EPA 450/3-79-006, June 1979
Control Techniques for Nitrogen Oxide Emissions from Stationary Sources- Revised - Second
Edition, EPA 450/3-83-002, January 1983
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Control Techniques for Volatile Organic Compound Emissions from Existing Stationary Sources.
EPA 450/2-78-022, May 1978.
Handbook: Control Technologies for Hazardous Air Pollutants (HAP Manual},
EPA-625/6-91-014, NTIS # PB92-135904
These documents briefly describe the efficiencies commonly achieved by major types of control devices in
current use and describe how to estimate emission reductions of these systems. A computer software
program, HAP-PRO, can also be used to estimate control efficiencies of various devices for Hazardous Air
Pollutants. This computer software program is available on the OAQPS Technology Transfer Network
Bulletin Board in the Control Technologies Center Area.
Some control devices reduce emissions of another pollutant besides the one for which they were
designed and intended. This is known as secondary or coincidental control. For example, venturi scrubbers
have been known to reduce SOX and lead emissions as well as paiticulate matter emissions. There are also
cases where the application of controls for one pollutant may slightly increase emissions of another pollutant,
such as NOX controls leading to increased CO or VOC emissions. Secondary control emission reductions
should be noted in the text, and, if quantifiable, should be included in the emission factor table or its
footnotes.
Tables should be designed or footnoted so that those pollutants not affected by a particular control
device are not labeled as "controlled" and do not have an emission factor presented for them unless it is
different than the uncontrolled emission factor. For example, SOX emissions would not be considered
"controlled" if the control device were a flare, and the table should reflect that distinction.
4.6.4 Outliers
An outlier is a data point that does not conform to the pattern established by other data. Generally, a
suspected outlier is much smaller or larger than the other data points. There are three basic ways an outlier
can occur: (1) mistakes in readings, (2) different processes being lumped together, and (3) actual deviation.
Mistakes in readings can occur during any stage of the data processing or in the data measurement process.
Transcription errors and calculational errors are common, but unusual readings from instruments may be
caused by power failures, improper calibration, malfunctioning instruments, contamination of samples, leaks,
chemical interaction, etc. Not adhering to an experimental design or a standard operating procedure (SOP)
can also affect recorded data. Because many hand calculations are needed to derive an emission rate per
production rate from the initial concentration and flow measurements, these should also be checked for any
data point that appears suspect. Many mistaken readings can never be detected or verified.
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Chapter 4 ^_^__ _^ Factor Development and Presentation Details
An apparent outlier may not, in fact, be an outlier at all, but rather an unusually high (or low) value
that is real - a rare deviation that is legitimate. Moreover, the rare deviation may be a datum of vital interest
in assessing human or environmental risks.
A number of statistical tests are available for treatment of outliers. Most of the statistical tests allow
selection of a level of significance that is related to the probability of being correct, if the test concludes that a
datum is an outlier. It is recommended that a statistician be consulted on the appropriate outlier test to use,
and what the results of the test mean.
No datum should be rejected or deleted solely on the basis of statistical tests, since there is always a
predictable risk of rejecting a value that represents actual emissions. Only if a mistake can be identified and
verified should an apparent outlier reasonably be rejected. Suspected outliers should remain in the data base
and be clearly identified as suspected or confirmed outliers (i.e., whether they are included or excluded from
calculation of the average emission factor). Even though statistical tests are a key component in justifying the
exclusion of datum that is believed to be nonrepresentative of the source category, exclusion of a suspected
outlier requires more than a statistical test; it also requires experience and judgment on the pan of the
technical personnel reviewing the data set. hi emission factor work, incorrectly grouping sources into
different sub-types (or into one general type) may be responsible for producing the suspected outliers.
4.6.5 Detection Limits
Sometimes the result of a stack test is not an emission rate, but the knowledge that the pollutant was
not present at or above the limit of detection of the test method. Given below are some guidelines on how to
use method detection limits (MDLs) for developing emission factors in such cases. Note that a run is a
single, complete traverse of the stack, and a test is the average of several runs, usually three.
• Determining a facility's average emission rate from a single test. If all of the runs from a test
are below the MDL, record the emission rate for that test as BDL (below method detection
limits), with the MDL clearly referenced. For clarity, the MDL should be expressed in
emission factor units, i.e., Ib/ton coal. If some of the runs are above detection limits and some
are below, use half of the MDL for the runs that were below in the calculation of the facility's
average emission rate (unless the BDL run's MDL was higher than the other runs' detection
values).
• Determining a source category emission factor from multiple tests. If all facilities have their
average emission rate recorded as BDL, report the average emission factor as BDL, with the
MDL clearly referenced. If there is a mixture of BDL's and numeric average emission rates,
use half of the test MDL for each BDL test as that facility's average emission rate, and
include that rate for the facility in the calculation of the average source category emission
factor (unless the BDL test's MDL was much higher than the other tests' detect values).
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• Determining an emission factor when the MDL varies among tests or runs. Some tests or
runs may have much higher MDLs than others in the same data set This can potentially lead
to a situation where averaging in half of a high MDL will bias the average high. If half of the
MDL for a BDL test is higher than all other single run detect values for the other tests in the
data set, then disregard the BDL test in calculating the average emission factor. If half of the
MDL for a BDL run is higher than all other single run detect values for that test series, then
disregard the BDL run in calculating the facility's average emission rate.
The following example illustrates these principles for the case where tests are available for three
facilities:
Test A : Three runs (all BDL); DL=50 mg/kg coal.
Report the results as "BDL, DL=50 mg/kg coal".
Test B : Three runs (7,9, and 11 mg/kg coal); DL=5 mg/kg coal.
Report the emission rate for the test as the average of the three runs, which is
9 mg/kg coal.
Test C : Three runs (6 and 10 mg/kg coal, and one run BDL; DL=5 mg/kg coal.
Report the emission rate for the test as the average of the three runs, using 2.5 for the run that
was BDL, i.e., (6+10+2.5)/3=6.2 mg/kg coal.
To determine an overall emission factor from the three tests, use only the Test B and C data because in Test
A. half of the DL (50) is 25, and that value is greater than any other single run detect value from Tests B and
C Therefore, (9+6.2)/2 = overall emission factor = 7.6 mg/kg coal.
• If a statistical outlier test is to be performed to determine whether any data points should be
eliminated from further analysis, then half of the MDL should be used as a numeric value for
those cases where a pollutant was below method detection limits.
• There are no "standard" criteria concerning how far above the MDL the data must be to be
considered quantitative rather than qualitative (e.g., 4 x MDL or 5 x MDL). The data would
not necessarily be considered non-quantitative if they were less than four or five times the
MDL. However, the precision of the values would be decreased the closer the data are to the
MDL, thus increasing the uncertainty of the values. The data would still be quantitative but
should be used with more caution.
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Chapter 4 Factor Development and Presentation Details
4.6.6 Use of Blanks
When reviewing source test reports, blank analysis results should be noted to determine the existence
and magnitude of contamination problems. The criteria for evaluating blank results apply to any blank
(method, field, etc.) associated with the samples. If problems with any blank exist, all data associated with
the test report must be carefully evaluated to determine whether or not the information should be use.
Guidelines for blanks analysis to be followed when evaluating test reports are:
• Positive sample results should be treated as suspect if the concentration of the compound in
the sample is not at least 10 times the amount in any blank for the following common
contaminants: methylene chloride, acetone, toluene, 2-butanone, and common phthalate
esters; or at least five times the amount for other compounds.
• In instances where more than one blank is associated with a given sample, qualification
should be determined by a comparison with the associated blank having the highest
concentration of a contaminant.
• If a compound is found in a blank but not found in the sample, no action is necessary.
• The resulting data should reflect the source test report's treatment of blanks. For example, if
in a test, results were corrected by subtracting any blank values, use the blank corrected
values for developing emission factors. If, however, test results were not blank corrected, do
not adjust the results, but use the uncorrected values for developing emission factors.
4.6.7 Units of Measure and Activity Parameter Selection
An emission factor is an estimate of the amount of a pollutant emitted due to some activity divided
by some measure of the level of that activity (commonly labeled as "thruput units"), hi order to be useful, an
emission factor must be reasonably accurate and easy to apply. The emission factor preparer should consider
the following guidelines before choosing both the activity on which to base the emission factor and the
measurement units for the activity.
• Choose an activity that directly influences the emissions, rather than an overall
process or activity given in the test reports. Emission factors for fugitive dust from
haul roads are thus typically given in terms of vehicle miles traveled rather than tons
of production. Combustion-only emissions should usually be related to fuel use
rather than to tons of production. Reasonable assumptions should be made by the
emission factor preparer when necessary to convert test report units to a common or
more appropriate basis.
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• Choose an activity such that a facility that does things differently, or more or less
efficiently than the tested facilities, will have these differences reflected in the
resulting emissions estimate. In the example above, a facility with longer haul roads
but the same production tonnage would show larger dust emissions. If a more
energy-efficient dryer were used, the combustion emissions would be lower.
• If an additional parameter significantly influences emissions, consider including it in
the emission factor. Sulfur oxide emissions from fuel combustion are usually based
on both the amount of fuel burned and the sulfur content of the fuel, because the
emissions depend on the amount of sulfur burned, not the amount of fuel burned.
Similarly, surface coating emission factors based on the amount of solvent in a
coating, rather than just the amount of the coating, will provide a more representative
estimate for more facilities.
• Choose an activity which can be easily tracked by the facilities in the source category,
and use measurement units which the industry uses if possible. If the industry uses
its own unique terminology or if the industry is moving towards metric units, those
terms and units can be used for an emission factor.
• For revisions to existing source category documents, try to use the activity and
measurement units which have historically been used, if they are still appropriate.
The AIRS AFS data base has thruput units associated with each existing SCC.
These units can also be found in the SCC list included as part of the FIRE data base.
• If possible, use units which can be readily converted between metric and English. An
emission factor in units of lbs/1000 Ib is the same in units of kg/Mg, and one
emission factor table with both units in the title can suffice. Units of Ib/ton can be
quickly converted to kg/Mg, especially where a footnote reminds the reader to divide
by two.
• Due to their continued common usage, English units are preferred for emission factor
tables. Conversions for metric units can be handled by one of the methods cited
above, or separate columns or tables for metric units can be added, at the discretion
of the emission factor preparer. When revising existing sections or documents,
evaluate whether it makes sense to revise duplicate tables.
• Satisfy needs for other units by providing conversion factors in footnotes. It is also
helpful to document the assumptions used in deriving values within the tables in the
footnotes, e.g., the BTU content of fuels or the thermal efficiency of engines.
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Chapter 4 Factor Development and Presentation Details
4.6.8 Assign Emission Factor Ratings
The emission factor rating is an overall assessment of how good a factor is, based on both the quality
of the test(s) or information that is the source of the factor and on how well the factor represents the emission
source. Higher ratings are for emission factors based on many unbiased observations, or on widely accepted
test procedures. For example, 20 or more source tests on different randomly selected plants would likely be
assigned an "A" rating if all tests are conducted using a single valid reference measurement method.
Likewise, a single observation based on questionable methods of testing would be assigned an "E". Emission
factors extrapolated from higher-rated factors for similar processes would be assigned a rating based on the
amount of similarity of the processes. The extrapolated factor would thus be rated no higher than the original
factor, and more likely lower, depending upon the similarity of the processes.
Material balance (such as combustion SOx or solvent loss) and theory-based emission factors (such
as vapor displacement equation) are special cases. Generally, material balance factors can be assigned an A
rating if the process emissions are consistent and well-characterized. Lower ratings should be assigned if the
material loss is variable or difficult to characterize.
Emission factor ratings are best characterized as follows:
A = Excellent. Emission factor is developed primarily from A- and B-rated source test data taken
from many randomly chosen facilities in the industry population. The source category
population is sufficiently specific to minimize variability.
B = Above average. Emission factor is developed primarily from A- or B-rated test data from a
moderate number of facilities. Although no specific bias is evident, is not clear if the
facilities tested represent a random sample of the industry. As with the A rating, the source
category population is sufficiently specific to minimize variability.
C = Average. Emission factor is developed primarily from A-, B-, and C-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 population is sufficiently specific to minimize variability.
D = Below average. Emission factor is developed primarily from A-, B- and C-rated test data
from a small number of facilities, and there may be 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.
E = Poor. Factor is developed from C- and D-rated test data from a very few number of facilities,
and there may be reason to suspect that the faculties tested do not represent a random sample
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Chapter 4 Factor Development and Presentation Details
of the industry. There also may be evidence of variability within the source category
population.
U = Unrated (Only used in the L&E documents). Emission factor is developed from source tests
which have not been thoroughly evaluated, research papers, modeling data, or other sources
that may lack supporting documentation. The data are not necessarily "poor," but there is not
enough information to rate the factors according to the rating protocol. "U" ratings are
commonly found in L&E documents and FIRE rather than in AP-42.
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 through E ratings. Stringent adherence to these criteria sound 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 n the background information.
4.6.9 Rounding and Significant Figures
To express numbers with the proper number of significant figures, it is frequently necessary to
"round" numbers. However, rounding of data should be done only when presenting the final emission factor
data in the tables, after all the calculations with a particular data set have been completed. Therefore, carry as
many digits as possible throughout the calculations from beginning to the end. When it is time to summarize
and tabulate the final results, the final numbers should be rounded to the appropriate significant figures.
To round a number, if the left-most digit to be removed is 5 or greater, then round up the right-most
digit If the digit to be removed is less than 5, the right-most digit remains the same. For example, when
rounding the following numbers to two significant figures:
3.43
3.45
3.46
rounds to
rounds to
rounds to
3-4;
3.5; and
3.5.
The term "significant figures" refers to how a number is described. For example 232,000 is a
number with three significant figures. All of the following numbers have three significant figures:
204,000; 204; 20.4; 0.204; 0.000204; and 2.04x10'3.
However, 204.0 implies that there are four significant figures. It should be noted that numbers less than 1.0
should have a leading zero as 0.204, not .204 without the leading zero. Leading zeros (0.204,0.0204, or
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Chapter 4 Factor Development and Presentation Details
0.00204) are not considered to be significant figures. With numbers like 100, or 100., it is not possible to
know how many significant figures the number contains unless it is expressed as l.OOxlO2, which implies that
there are three significant figures.
It is suggested that for consistency when rounding numbers for final emission factor tables, the
values be rounded to two significant figures, where possible. In some cases, the data may permit rounding to
three significant figures. A general rule of rounding is that the final rounded figure should contain no more
significant digits than the number with the least number of significant digits used in the calculations.
4.7 BACKGROUND DOCUMENTATION
i
4.7.1 Background Documents
Concurrent with AP-42 section preparation, a background document discussing all references,
calculations, and other pertinent information is prepared to undergo external review along with the section.
The background document should identify all data, discuss their quality ratings, 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.
Each piece of information that is evaluated for use in developing the section should be summarized.
Emission test report summaries should include the available description of the process being tested, existing
controls, individual test results for all pollutants evaluated, problems identified by the test contractor, and
problems identified during the review of the test by the section author.
Each emission factor should be documented so that the basis for the factor is clear. Specific material
to be summarized and contained in the background document is as follows:
• Text describing the results of the data gathering effort. Items to address are where the data
come from, the type of sources tested, all relevant process design and operational data
available in the report, the quality of the data, the test methods used, the size of the units
tested, how well does the data represent the source category, etc.
• A summary of each emission test report, with a list of all relevant data for each individual test
run used in calculating the emission factor, with specific references to page or table numbers
in the material in which these data were found. Note that for updates to AP-42 sections this
may include older, but still relevant, data. Any corrections or adjustments that were made to a
test report should be noted and explained.
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Chapter 4 Factor Development and Presentation Details
• A complete description of the calculations. If appropriate, sample calculations are highly
recommended (A hard copy of all electronic spreadsheets should be included in the
background files).
• A complete record of all assumptions, technical procedures, and rationale used in calculating
or reducing the data.
• A list of the primary references actually cited in the emission factor document as listed in the
AP-42 section and L&E document
• A list of secondary references used for background information during development of the
emission factor document but not cited explicitly.
• The draft AP-42 section for external review, clearly labeled as such.
• A summary of the significant comments received on the external review draft, the resolution
of those comments, and any other significant changes made to the draft to create the final
published section. This summary is added to the background document after external review.
The wordprocessing package of choice is WordPerfect* Version 6.1 for Windows. The background
document on Portland Cement (BCI 1S06.ZIP) is available from the CHIEF Website or on the Air CHIEF
CD for guidance on format and content.
In order to help Website users find the files and to avoid having electronic section and background
files overwritten on the Website due to duplicate names, the following file naming conventions are suggested:
For Background Documents: BXXSYY-2.WPD
For Final AP-42 Sections: CXXSYY-Z.WPD
For Draft AP-42 Sections: DXXSYY-Z.WPD
where: XX is Chapter number
YY is Section number, and
Z is Subsection
Note that all of the files will appear on the CHIEF Website with a .ZIP extension.
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Chapter 4 Factor Development and Presentation Details
4.7.2 Background Files
A file containing all of the references (test reports, journal articles, etc) should be maintained to
provide the basis for current emission factors and supporting references when the applicability or accuracy of
emission factors is questioned. For instance, transcripts of personal and telephone communications should be
made and included 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) if the document is
revised at a later date. For ease of use, this file should be labeled according to the section numbering system
used in AP-42. For L&E documents, the pollutant name should be clearly labeled. Note that the EPA has a
long range goal of storing all of the background files electronically. The background file should include the
following information, clearly labeled and stored in the following categories.
• The current AP-42 section or L&E document
• The version of the background document supporting the current version of the AP-42 section
or L&E document.
• A copy of any electronic spreadsheets used to perform emission factor calculations or
statistical analyses.
• Previous published versions of the AP-42 section in reverse chronological order (newest first,
oldest last)
• A marked-up copy of the previous published AP-42 section, if appropriate, clearly showing
the revisions.
• A list of the people and organizations that were requested to review the latest document.
• Copies of comments received from reviewers.
• All references cited.
• References not cited in the background document but that provide supporting information for
future use.
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Chapter 4 ___ Factor Deretopment and Presentation Details
4.8 AFTER EXTERNAL REVIEW
After external review comments have been received, the author should meet with the project leader to
discuss how the comments will be addressed and whether extensive changes to the draft are warranted. If
sufficient additional data becomes available during the external review period, or if extensive changes are
otherwise needed, a revised draft should be prepared for a second external review. If a second external review
is not needed the section can be finalized by addressing the comments, adding Source Classification Codes
(SCCs) to the document, and preparing a summary of the emission factor changes to be made to the Factor
Information REtrieval (FIRE) System data base.
4.8.1 SCC/AMS Code Assignments
Source Classification Codes (SCCs) are a means of organizing air pollutant sources into related
groups. Because they are used as a key identifier for emission sources by both inventory preparers and permit
reviewers, it is desirable to assign these identifiers to the emission factors as well. Emission factors must be
tied to an SCC in order to appear in the AIRS or FIRE systems. The emission factor developer should use his
or her familiarity with the source category to recommend revision or additions to the SCCs in AIRS and FIRE
where necessary to improve the clarity of the data presented. Address such recommendation to Ronald Ryan,
Emission Factor and Inventory Group, MD-14, The Environmental Protection Agency, Research Triangle
Park, NC 27711. The SCCs should be included in the emission factor tables. It is suggested that they appear
on the flow diagrams as well. Addition of the SCC codes should be done after the section has been externally
reviewed if extensive changes are anticipated, or it can be done earlier if the author is confident with the
process description and the subcategonzation of the data.
The SCC is an eight-digit code divided into four fields in the pattern "1-22-333-44," with each level
having a corresponding description as follows:
• Field 1 - the major emissions type;
• Field 2 - the major industry;
• Field 3 - the fuel consumed or the end product; and
• Field 4 - specific combustion equipment or unit operations.
SCCs vary in the amount of detail. For some processes, there are SCCs for individual release points
within the process, hi other cases, an entire process may be represented by a single SCC. In addition, an
emission source may be represented both individually and as part of an overall process SCC. SCCs should
not be used to distinguish all of the add-on control devices that may be used and which will have different
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Chapter 4 Factor Development and Presentation Details
emission factors. The SCC is used to identify the process, not the level of control. However, different
process designs which result in different emissions levels should be assigned different SCCs.
Area and mobile sources are sources for which emission estimated are not made for each individual
source, but are instead estimated as an aggregation of individual sources (e.g., architectural coating, pesticide
application, and on-road motor vehicles). To "extend" the SCC system of codes to area and mobile sources,
EPA developed a separate coding system, called Area and Mobile Source (AMS) codes, that follows the same
general structure as SCCs, but instead uses a 10-digit code patterned "11-22-333-444."
The complete and current version of the SCC and AMS codes resides on EPA's mainframe computer
in tables within AIRS. The FIRE data base also contains a file of the combined SCC and AMS codes current
as of the FIRE release date. The emission factor developer should review the FIRE SCC list to assign SCC or
AMS codes to each emission source included in AP-42 and L&E tables. Full 8- or 10-digit SCCs or AMS
codes should be identified. If there is no existing code for an emission source, or if the description for an
existing code needs to be revised for clarity, the author should contact EFIG to have an SCC assigned to the
source.
4.8.2 FIRE Data Entry
The Factor Information REtrieval (FIRE) System data base is EPA's electronic listing of rated and
unrated emission factors, including those from AP-42 and L&E documents. It is used by EPA's AIRS
mainframe and by many States and private software vendors as the source of updated emission factors for
their computer systems. Therefore, it is essential that the results of any AP-42 or L&E updates be accurately
reflected in FIRE. This requires that the emission factor document be unambiguous, that SCC codes be
assigned and used in the emission factor document, and that the information related to each emission factor
update be submitted to the Emission Factor and Inventory Group in the form that it should appear in FIRE.
Submittal of all updates in such a form will also allow EPA to explicitly tell users what has been added,
deleted, or revised as a result of an AP-42 Supplement or L&E document publication. In addition to just
getting new emission factors into FIRE, the author should insure that existing factors are revised, deleted, or
confirmed as being still valid. These decisions should already have been addressed throughout the factor
development process if the author checked the FIRE data base for existing information at the start of the
project.
Preparation of the materials described below should occur as part of the final revisions to the factor
document. Any needed SCC codes must already have been assigned per the preceding section, and no
updates to FIRE will be made until the AP-42 section or L&E document has been placed on the CHIEF
Website as "Final". The author should prepare and submit a Lotus spreadsheet file containing the
information shown below. Actual entry of the data into FIRE will be done by EPA. The file should contain
the following columns, with each row representing all of the information for a given emission factor.
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Chapter 4 _^__^_ Factor Development and Presentation Details
ACT New, rev, del, or ok
SCC 8-digit code, or 10-digit AMS code with A preceding
POL Pollutant name (from existing FIRE list, if possible)
CTL1 Primary control device (from existing FIRE list, if possible)
CTL2 Secondary control device (from existing FIRE list, if possible)
RECJTO FIRE record id number, if applicable
OLD_EF Existing emission factor
OLD_STD T if units are standard for SCC, or F if not, with non-standard units given
NEW_EF New or revised emission factor
NEW_STD T if units are standard for SCC, or F if not, with non-standard units given
REF ' Primary reference code (?? if not yet in FIRE, w/footnote)
QUAL New factor's quality rating
RANGE Lowest and highest facility averages (optional)
TESTS Number of facilities averaged (optional)
METH Test method used (optional)
NOTES Any notes necessary to use the factor
P ARAM Any process parameters that may have influenced emissions
EXPLN Explanations for OLD_STD or NEW_STD entries, or to identify what was
revised if not the emission factors - does not go into FIRE
For revised records, all columns should be filled in with the information to appear in FIRE. The last
six columns are optional. The same applies to any new records, except OLD_EF and REC_ID will be left
blank by the author. EPA will fill in the REC_ID. For deleted and ok records, only the first eight columns
should be filled in.
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APPENDIX A
AP-42/L&E STYLE GUIDE AND EXAMPLE SECTION
-------
AP-42/L&E FORMAT/STYLE SPECIFICATION SHEET
These are the style guidelines used to produce the AP-42 5th Edition and should also
be followed to produce L&E documents. This style sheet consists of three sections, the first
intended as an aid for technical writers and editors, and the second as an aid for secretaries
preparing sections, and the third for use for word processing and graphics support.
ATTACHMENTS TO THIS STYLESHEET:
• Example disk with file templates.
• Example from AP-42 5th Edition (Note that because of the recent decision to use the
same style for L&E documents that is now used for AP-42 sections, L&E documents
will ndt resemble those prepared so far.)
SECTION 1: GUIDELINES FOR WRITERS AND EDITORS
Section Headings 2
Acronyms 2
Spelling 2
Hyphenation 3
Units and their Abbreviations 3
Tables 3
References 3
SECTION 2: GUIDELINES FOR TYPISTS
Initial Codes 5
Footers 5
Text, Headings, & Subheadings 6
Punctuation/Spacing 7
Lists within a Text Paragraph 7
Numbers 8
Figures 8
Tables 8
Equations 11
References 11
SECTION 3: ELECTRONIC PUBLISHING REQUIREMENTS
Fonts 12
Headings 12
Figure Quality 12
Landscape Figures/Figure Captions 12
Formatting 13
Equations ]4
Subscripts and Superscripts 14
AP-42 5TH EDITION (Revued 6/30/95) 8/95
-------
SECTION 1: GUIDELINES FOR WRITERS AND EDITORS
SECTION HEADINGS
• Number all section headings through the 3rd level. It is acceptable not to number 4th- or 5th-order
headings if few occur in a section. Do not number the heading for references.
• ALL words initial caps always (including the words "and, of, to, for", etc.) for ALL levels of
headings after chapter titles
ACRONYMS
• Always introduce in parentheses after the first use in a section, as singular even if plural in context.
then use as singular or plural depending on context, e. g., VOC or VOCs not VOC's. It is OK to start
sentences with acronyms after introduced, e. g., "EPA..." (note: not "The EPA...") and "CO
emissions decrease..."
• Specific cases:
o NA = not applicable (ONLY; not "not available"; if "NA = not available" is used, change it
toND)
o ND = nodata
o PM-10, not PM10
o SCC = Source Classification Code
SPELLING
Use standard and check variants, e. g., use phosphorus, not phosphorous.
• Specific cases: • Capitalization specifics:
o add-on (not addon or add on) o federal (not Federal)
o byproduct (not by-product) o state (not State)
o condensable (not condensible)
o data base (not database)
o feedstock (not feed stock)
o firebox (not fire-box)
o flow rate (not flowrate)
o fly ash (not flyash)
o half-life (not halflife or half life)
o off gas (not off gas)
o waste water (not wastewater)
• The correct definition of PM-10 is particles "equal to or less than 10 micrometers in aerodynamic
diameter."
• Regarding mentions of paniculate matter, the term "paniculate" is preferred over "particulates".
8/95 (Revued 6/30/95) AP-42 Format/Style Specification Sheet
-------
HYPHENATION
• Use legitimate hyphens within text and at end of lines. Usually delete for prefixes and avoid: be
consistent with terms throughout document.
UNITS AND THEIR ABBREVIATIONS
If the unit and correct abbreviations for emission factors used in tables are not introduced in the text.
they should be added as follows: "Factors are expressed in units of.. .[spelled out version, followed by
abbreviation in parentheses]".
• Always spell units out the first time used, except for temperatures, then introduce the abbreviation
in parentheses, and then use abbreviation consistently thereafter. For temperatures only, use # °F
and do not spell out Celsius or Fahrenheit; also see below
• Specific cases:
o liter (L) not lower case "L" (1) or script "1"
o micrometer (urn), not micron
o Temperature: always "solid" (no spaces): 572°F not 572 °F, etc.
• Scientific notation and decimals are both acceptable within a table
TABLES
• AP-42 tables should use English units common to the source category described. Conversion
factors to metric units can be given in footnotes or metric emission factors can be given in a
separate table or in the same table as the English factors, space allowing.
• Standard text for Clean Air Act HAPs footnote: "Hazardous air pollutant in the Clean Air Act."
REFERENCES
• Always place all author's initials first or first name first (not inverted, with last name first)
• Always italicize "et a/.,"; if * 3 authors, delete all but first author's name, then a comma, "et al.,"
• Titles of documents and publishing organization: Use initial caps for all words (e. g., "Oregon
Department Of Environmental Quality"). Always italicize titles
The following are selected examples of the reference format used in AP-42.
Legislation:
1. The Rehabilitation Act Of J973, §504,29 U.S.C. 794.
AP-42 5TH EDITION (Revised 6/30/95) 8/95
-------
oo
1
EXAMPLE ENGLISH UNIT TABLE
Source Category
Pollutant
Emission Factor
(Units are Ib of
pollutant/ton Al produced.)
EMISSION
FACTOR RATING
Notes
c«
-------
AP-42 5TH EDITION (Revised 6/30/95) 8/95
-------
Federal Register Notice (Vol 53, p. 5573):
2. Standards OfPerformance For New Stationary Sources: New Residential Wood Heaters, 5 3 FR 55 73,
February 26,1988.
Code Of Federal Regulations Notice (Title 40, Part 60, Subpart N):
3. "Standards Of Performance For Iron And Steel Plants", 40 CFR 60.N.
EPA publications (with an EPA document number):
4. 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.
With three or more authors:
5. C.A. Simons, et al, Woodstove Emission Sampling Methods Comparability Analysis Andln-situ
Evaluation Of New Technology Woodstoves, EPA-600/7-89-002, U.S. Environmental Protection Agency.
Cincinnati, OH, January 1989.
One of a bound collection of papers:
6. D.C. Current, "Commercial Bakeries As A Major Source Of Reactive Volatile Organic Gases",
Emission Inventory/Factor Workshop: Volume 7, EPA-450/3-78-042a, U.S. Environmental Protection
Agency, Research Triangle Park, NC, August 1978.
With contract number only (if no EPA document number is assigned):
7. Particulate And Lead Emission Measurements From Lead Oxide Plants, EPA Contract No. 68-02-
9999, Bimbo Research Corp., Youpon, OH, August 1973.
Unnumbered:
8. S. Wyatt, etal, 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.
Source test:
9 Source Testing Of A Waste Heat Boiler, EPA-75-CBK-3, U.S. Environmental Protection Agency,
Research Triangle Park, NC, January 1975.
Non-EPA Source test:
10. S.G. Barnett, In-home Evaluation Of Emissions From Masonry Fireplaces And Heaters, OMNI
Environmental Services, Inc., Beaverton, OR, September 1991.
Other Agency reports:
11. S.G. Bamett and P.O. Fields, In-home Performance Of Exempt Pellet Stoves In Medford, Oregon, U.S.
Department Of Energy, Oregon Department Of Energy, Tennessee Valley Authority, and Oregon Department
Of Environmental Quality, Salem, OR, July 1991.
Privately published report:
12. S. Dembach, Woodstove Field Performance In Klamath Falls, OR, Wood Heating Alliance,
Washington. DC, April 1990.
Periodical:
13. 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, 9(7):643-67, July 1975.
8/95 (Revised 6/30/95) AP-42 Format/Style Specification Sheet 7
-------
Paper:
14. 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.
Book:
15. L. Sullivan Agnew, et al, Flow Of Information In Visionary Heavy Metal, Volume 1: Notwithstanding
The Rumor, Purdue University, West Lafayette, IN, June 1973.
Privileged information:
16. Confidential test data, Bozo Contractors, Inc., Caries, NC, December 10,1941.
Personal or official conversation:
17. 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 Of The Interior, Washington, DC, January 15,1993.
AP-42 5TH EDITION (Revised 6/30/95) 8/95
-------
SECTION 2: GUIDELINES FOR TYPISTS
INITIAL CODES
Software Text:
WordPerfect® Version 6.1 for Windows
Document Font:
Superscripts and Subscripts (83% in text and tables)
Left/Right Margin
Top/Bottom Margin for Chapter Introduction Page only:
Top/Bottom Margin for First Page of Section only:
Top/Bottom Margin for Subsequent Pages:
Footer A/Footer B
Tabs: Absolute (w/firsttab at 1", every 0.5")
Text Spacing:
Justification:
Widow/Orphan Protection.
Table and Figure Options: Borders
Figure Options: Captions
Print Options in Initial Settings:
Times New Roman 11 pt
Times New Roman 9 pt
r/r
27.5"
1.57.5"
17.5"
See Section on Footers
17.5"
1"
Left
On
None
Placed Below Figure
1 Binding Offtet
2 Number of Copies
Multiple Copies Generated by
3 Graphics Quality
4 Text Quality
5 Redline Method
6 Size Attribute Ratios
(% of Normal)
7 Banner
8 Form Number
o-
1
WordPerfect
High
High
Printer Dependent
Fine 60%
Small 80%
Large 120%
Very Large 150%
Extra Large 200%
Super/Subscript 83%
No
0
FOOTERS
For all pages, these should be 0.5 inch above the bottom of the page. Note the following
examples. For odd-numbered pages:
1/95
Stationary Internal Combustion Sources
3.1-1
(not 01/95) [or use date given)
{Chapter title, initial caps only]
[Section Number vv/page number}
8/95 (Revised 6/30/95)
AP-42 Format/Style Specification Sheet
-------
10 AP-42 5TH EDITION (Revised 6/30/95) 8/95
-------
For even-numbered pages, nearly the same information is used, but order reverses:
3.1-2 EMISSION FACTORS 1/95
/Section number w/page number] (Volume title, all caps] [date]
TEXT, HEADINGS, & SUBHEADINGS
All text should be Times New Roman 11 pt. Always use super- and subscripts that are 9 pt.
(83% in text and tables). Headings to introduce a chapter should be 15 pt. & all caps. The main heading of a
section should be formatted as a Ist-order heading (i. e., initial caps and bold) regardless of the number of
digits (some sections will begin with a 3- or 4-digit heading number). Number all section headings through
the 3rd level. Mark all heading for the table of contents, but just headings (i. e., no superscript numbers). Do
not, under any circumstances, use the paragraph numbering or outline features. Note the following specifics:
• Spacing between section number and heading should always be 2 spaces; it may not align with <\\
indent because number of digits (width) of section numbers vary
• Amount of ^ indents should always be 0.5 inch. Always use indents (F4); do not use tabls even
for lists that use number or bullets (reset amount of indent if necessary)
• Do not use hard returns within text paragraphs or lists that begin with numbers or bullets
• No right text margin justification
• Style of 3rd-, 4th-, 5th-, or higher-order headings may vary depending on what heading level a
section begins with and whether the subsection is numbered. Always flush to left margin (not
indented); use hyphen with 1 space before and a hard return after; see the following examples
(note: [] = required space, imbedded WordPerfect command, or note to reader):
Subheading Tit\e{\-[Hardreturn]
After only a 0.5-inch ^ indent and no intervening line of space, text
follows... [unnumbered heading] OR
2.1.3.3[]QAcid Gases[\-[Hard return]
After only a 0.5-inch ^ indent and no intervening line of space, text
follows,
"The chief acid gases... [numbered heading]
• It is imperative to use required spaces in text as follows: Appendix[]A, Table[]#, and
#[]unit; do not allow such items to split at the end of text lines
• Capitalize terms such as the following (and above) as specific referrals: Section[]2.2,
ChapterQ2
• Do not use hard returns within text paragraph or lists that begin with numbers or bullets
8/95 (Revised 6/30/95) AP-42 Format/Style Specification Sheet 11
-------
EXAMPLE OFAP-42 SECTION HEADING LEVELS
1.1 First Order Heading
1.1.1 Second Order Heading"
Text for this section should begin on this line.
1.1.1.1 Third Order Heading -
Text for this section should begin on this line.
Fourth Order Heading -
Text for this section should begin on this line.
PUNCTUATION/SPACING
• Punctuation should always be outside quotes unless it is a part of the quoted passage
• Use 2 spaces after a colon, ":", except in ratios: " 10:1" or in periodical references: "9(7):643-
67".
• Always use 1 space (required) in cases such as "e. g.," or "i. e.,"
• Always use 1 space between authors' initials in list of references
• Always use 1 space (required) in U. S.; use U. S. even as a noun (but do not change it if it is
spelled out)
• Delete any space between # & "%": e. g., "77%", not "77 %"
• Do not use apostrophes with years, i. e., use " 1970s", not" 1970's"
• Dashes are always "en" dashes, with a required space to each side
LISTS WITHIN A TEXT PARAGRAPH
If numbered, use both parentheses: e.g., "(1)" not"!)". For unnumbered lists outside text, use NO
bullets: instead use hyphens. From left margin, use the 0.5-inch ^[ indent, then a hyphen followed by another
F4 indent set for 2 spaces, as shown in the following example:
Text starts with capital letter and usually no end punctuation, but this
is case-specific; if internal punctuation is used (i. e., a series of items
with commas), each item might end with a semicolon ";". If this is
done, the next to last item should end with "; and", and the final one
should end with a period.
Also, a numbered list outside the text is fine, and the format should be similar with 1 or more levels
to the list:
1. After the number (or letter) and a period, use a 2-space indent, then text starts with a capital
letter, and end punctuation is case-specific if needed.
a. Text again starts with a capital letter; use case-specific end punctuation if needed for clarity.
12
AP-42 5TH EDITION
(Revised 6/30/95) 8/9S
-------
NUMBERS
• Always use numerals, e. g., 3 to 5 days, 4 plants, 5 percent (not five percent) except at the
beginning of a sentence. Use % sign in tables and table footnotes (column heads and footnotes):
but not in text
• In 4-digit numbers, comma use is optional except when used with numbers of 5 or more digits,
e. g., 1000°F is OK, but also 1,000 to 10,000 Ib
• Insert a zero before the decimal if none is used in a given number
^
• Be sure a space appears before the "E" in "1.10QE-03" or "1.10QE-K)3"
• Style for ranges (values & references):
o Text and table guts: 1-2(1 required space on each side of hyphen)
o Text reference citations and table footnotes; use: 1-2 and 3,5
•(note: no spaces, not "3,5")
• SCC numbers: should be "solid", i. e., no spaces; insert hyphens per the formula 1-2-3-2 as
follows: #-##-###-##
FIGURES
Figures should not have borders.
• For text references, always cite the word "Figure" and the full number for each.
Text references should not cite a range (e. g., Figures 5.2-1 through 5.2-4)
• Caption font: Should match text font style (Times New Roman 11 pt.)
• Caption style: 1st word only initial cap (not all words), ends with a period, and centered relative
to the figure. If SCCs appear in the figure, on the next line (no intervening line of space), center
the following statement: "(Source Classification Codes in parentheses.)" If a figure must be
presented in "landscape" orientation, the caption must be centered below the figure within (and
parallel to) the right margin. Do not place "SCC" before the SCCs given throughout the figure
TABLES
• Landscaped tables are to be put into Table Boxes
• For text references: use "Tables 9.3.2-1 and 9.3.2-2", not "Tables 9.3.2-1 and -2". If a range of
tables is mentioned, each full number should be cited (e. g., "Tables 5.2-2,5.2-3, and 5.2-4"), but
the word "Table" does not need to be repeated
• Font sizes: title, entries, and footnotes: should always be same size as text font (11 pt.). Table
entries ("guts") ONLY may use 9-pt. font to avoid continuing table. Do not make title or
footnotes the same size font as table if a 9-pt. font is used
8/95 (Revised 6/30/95) AP-42 Format/Style Specification Sheet 13
-------
• Title format, if too long to fit on 1 line: Avoid only 1 or 2 words on second line and split at a
logical place, e. g., "EMISSION FACTORS FOR [hard return] ABRASIVE
MANUFACTURING"
• If the table title subhead "EMISSION FACTOR RATING: [rating letter here]" is used and any
exceptions are footnoted, add the following after the rating letter: "(except as noted)"
• Style if continued: use only header with table # and "(cont.)", no footers: do not repeat title: e. g.,
- "Table 9.3.2-1 (cont.)." Note that no period follows the table number but use a period both after
"cont." and following the closing parenthesis
• Boxes, "downlines": all tables should use only single-line boxes (not double) and no horizontal
lines after column headings. Use vertical downlines from top to bottom only for major column
subheads (not subcolumn headings)
• Column headings: placement & style: centered over column [except possibly first column may be
flush left; this is case-specific)], "stacked" from the "bottom up" (i. e., the line between column
headings and table guts). Use all initial caps for words, with one exception: EMISSION
FACTOR RATING; this term should always be all caps within a table column heading or
subheading or footnote, or as a subheading for table title. Capitalization of unit abbreviations
must be case-specific
• Columns: Widths should be equalized as much as possible. "Use column command to decimal
align and center numbers within the individual column except in cases where space problems may
arise (i. e., to avoid continuing a table or using a smaller font). Always use tabs and adjust
spacing if not standard; do not use spaces.
'In Table Edit:
2 Format
2 Column
3 Justify
5 Decimal Align
For Centering Columns w/decimals:
2 Format
2 Column
4 #Digits (Enter a number of decimal places to achieve a centered column
of numbers with decimals.)
EXAMPLE TABLE WITH DECIMAL ALIGNED NUMBERS
VOC1
Use
Aerosol products
Household products
Toiletries
Rubbing compounds
National
Emissions
tons/vr
37.6
2.01
14.5
6.8
Per Capita
Emission Factors
Ib/yr
3.5
1.9
1.4
0.64
Ib/day
9.6
5.2
3.8
1.8
14
AP-42 5TH EDITION
(Reviacd 6/30/95) 8/95
-------
VOC1
Use
Polishes and waxes
National
Emissions
tons/yr
53
Per Capita
Emission Factors
Ib/vr
0.49
Ib/dav
13
When the only entry is a footnote, precede with an "em" dash (control V: 4,34)
Left column terms: capitalize 1st word only (except possibly for specific terms, e. g., "Pre-
Phase")
Align text entries on the left and indent subsequent lines 2 spaces relative to first character.
Entries in subsequent columns should align with last "spillover" line of table text entry (but not
SCC number in parentheses)
Footnotes:
o Within a footnote, the term "EMISSION FACTOR RATING" must lead, and can be
preceded only by a reference number.
o Order: always left to right and top to bottom; correct as necessary; use ONLY
superscript letters
o Specific letters not to use or to double: i, 1, & o; but aa, bb, etc., are ok if needed
o Placement: no return or line of space between table bottom (except that resulting from
use of superscript letters to avoid overstriking table box line)
o Alignment: Should align with table width on the left and right and not extend beyond.
Use an indent (with 1 space only) after superscript so subsequent lines align with first
text character, not text flush to left margin; also a second column on same page is OK to
avoid continuing table if not confusing
o Use 1 space between superscript letter & text as noted above; use the advance down code
(0.05) between the bottom line of table and the beginning of superscript letters
EXAMPLE TABLE REFLECTING POSITION OF SUPERSCRIPTED LETTERS
Particle Size*
(Mm)
15
15
Cumulative Mass % s Stated Size
Uncontrolled
40
40
Multiple
Cyclones
99
99
ESP
83
83
Cumulative Emission Factor"
(Db/ton] Coal, As Fired)
Uncontrolled
2.8A
2.8A
Multiple
Cyclones
1J8A
1J8A
ESP
0.046
0.046
Expressed as aerodyiiamic «l««*alent diameter.
8/95 (Revised 6/30/95)
AP-42 Format/Style Specification Sheet
15
-------
o ALL acronyms used in table but not defined previously in text should be defined at the
end of footnote "a" (but not chemical terms/nomenclature; if any are used that were not
previously introduced/identified in the text, it is OK because it is assumed all readers will
recognize standard chemical terms)
16 AP-42 5TH EDITION (Revued 6/30/95) 8/95
-------
EQUATIONS
Make sure first thing is "Func {" and do not use "vertical" (for Super and Subscripts) or "scalesym"
(6.234xl(T4) P At V D0
E = - - - - 1— i + L, D
V T
, d
d d
FUNC {E^ {(6.2341
X'10X{-4})~{P~A~
t~V_o~'D_o}} over
{V_s~T} ~f~
{L_d~D_d}}
Number equations if more than 1. hi building an equation Also, placement of "where:" should be
alone on a line below equation, usually flush to left margin (or possibly indented; these will be case-specific),
with list of terms defined beginning on line below, aligned by "="
where:
E, = emission factor for VOC, mass per vehicle (lb/vehicle) (exclusive of any add-on control
devices)
A, = area coated per vehicle (frVvehicle)
c, = conversion factor: 1 ft/12,000 mil
Tf = thickness of the dry coating film (mil)
REFERENCES
• Use the endnote feature for numbering text references; do not use superscripts or footnotes
• List should start immediately following text (no white space) unless table(s) follow text (i. e.,
tables should not split up references). Also, style for text citations should be: "...blah.10" not
"...blah10."
• The subheading for references should be "References For Section [insert section number]". Do
not number this subheading
• Only in list of references, set a 0.5-inch tab from the left margin so all reference text aligns on
the left regardless of the reference number digits
EXAMPLE:
I. Second Review Of Standards Of Performance For Sewage Sludge Incinerators,
EPA-450/3-84-010, U. S. Environmental Protection Agency, Research Triangle Park,
NC, March 1984.
8/95 (Revised 6/30/95) AP-42 Format/Style Specification Sheet 17
-------
SECTION 3: ELECTRONIC PUBLISHING REQUIREMENTS
In order to incorporate AP-42 sections and L&E documents to an electronic form, such as a CD-
ROM version, the document must be compatible with CD-ROM format. The following are requirements for
electronic publishing of these documents that should be adhered to.
FONTS
Change the Font to Times New Roman 1 Ipt (Make absolutely sure that the Base Font, shift-F8, 3.3
also is Times New Roman 1 Ipt and that the 3D printer is defaulted to Times New Roman 1 Ipt) and change
the tabs to absolute tabs 1,.5 or whatever the tabs should be for special circumstances.
HEADINGS
Make sure each heading is as follows:
• [Center]SECTION2.0[HRt]
[Center]EMISSIONS FROM MANUFACTURING[HRl][HRl][HRt]
• 2.1 [Tab]EMISSIONS SUMMARY[HRt][HRt]
• 2.1.1 fTablMotor Vehicle EmissionsrHRtirHRt]
• 2.1.1.1 [TabJProcess Emissions-[HRt]
FIGURE QUALITY
Check each figure and make sure that it can be seen properly in WordPerfect. Mark table titles and
figures for the List of Tables and List of Figures.
• Drawings are created in a drawing program with excellent export capabilities (that is, vectored
graphics with editable text capability, such as with Corel Draw, WordPerfect Presentations, or
the graphics software of WordPerfect for Windows. Note that other graphics software (e.g.,
Freelance for Windows) can be used but only if fixed font size is used to avoid the problem of
text extending beyond space designed for it.).
Arrow heads are sized: .008
Lines are sized: .02
Fonts: Times Roman, 9 pt within the graphic
Save original drawing file
Select all & export as .pcx (selected only):
COLORS: black & white
SIZE: Itol
RESOLUTION: 300 DPI
Select all, group & export as .wpg (selected only):
COLORS: 16 colors
EXPORT TEXT AS: Curves
LANDSCAPE FIGURES/FIGURE TITLES
Figure Box Specifications.
Selection 6. Horizontal: Left
18 AP-42 5TH EDITION (Revised 6/30/95) 8/95
-------
Selection?. Size: 6" wide by 8.99" high
Selection 9. Rotate 90 degrees (Alt F9)
Selection 1. Type in figure filename.
Below are requirements for captions when creating landscape figures.
Selections. Horizontal: Right
Selection?. Size: 0.168" wide by 8.99" high
Selection 9. Rotate 90 degrees (Alt F9)
Center and type in figure title.
f
Note: These numbers are chosen from "definition": Figure Screen.
FORMATTING
• Do'not use the Columns feature in WordPerfect, Use the table layout instead.
• Make sure the center and right justify functions in table cells are used. Do not center using the
regular center command and do not right justify using the regular right justify command. Folio
interprets these as a tab and a center and pulls all columns to the center of the page. When
using bullets or dashes in tables, set a tab, do not space over from bullets or dashes, TAB.
• Do not use the WordPerfect 5.1 line draw feature. There is no line draw feature in Folio.
However, you can set a left tab and a right tab and use the underline tabs and spaces feature to
draw a line underneath grouped heads in tables.
• If there are landscaped or legal size tables, include them at the end of the file, not in separate
files. This will help to ensure all of the files needed to complete a section are included.
• Use hard spaces and hard hyphens when typing phrases that should be kept together. At this
time Folio does not have these features and there is no way to put them in. The WordPerfect
5.1 text wraps because Folio is designed to display text horizontally within the window for ease
of viewing.
• Use the automatic Table of Contents feature in WordPerfect 5.1. This will be automatically
translated by Folio.
• Use the endnote feature in WordPerfect 5.1 for references. These come over as pop-up links in
Folio and no further formatting has to be done for them.
• Use hard returns only at the end of paragraphs. A hard return in Folio indicates the end of a
record.
• Convert Lotus 1-2-3 and Quattro worksheets to Ascii format.
• If there are WordPerfect 5.1 graphics (*.wpg files) in a document, make sure they are exactly
the way they should appear. They cannot be edited in WordPerfect 5.1 or Folio.
• Make sure all disk files for each section, including appendices, are together in one zip file and
that a systematic file naming scheme is used.
• Do not use outline or paragraph feature. * Folio does not translate this feature.
8/95 (Revised 6/30/95) AP-42 Format/Style Specification Sheet 19
-------
EQUATIONS
Make sure first thing is Func {. Do not use vert in equations, use super or subscripts. Do not use
SUBSCRIPTS AND SUPERSCRIPTS
Do not use the Advance Up or Advance Down feature in WordPerfect 5.1. Folio does not recognize
this. Use superscripts and subscripts instead. Printer description file (*.prs) should be modified to default to
Times New Roman 9pt. Also, the WPS 1 setup under Initial Settings, Print Options, Size Attribute ratios,
Super/Subscript, should be 83%.
20 AP-42 5TH EDITION
-------
EXAMPLE AP-42 SECTION
-------
11.6 Portland Cement Manufacturing
11.6.1 Process Description1'7
Portland cement is a fine powder, gray or white in color, that consists of a mixture of hydraulic
cement materials comprising primarily calcium silicates, aluminates and aluminoferrites. More than 30
raw materials are known to be used in the manufacture of portland cement, and these materials can be
divided into four distinct categories: calcareous, siliceous, argillaceous, and ferrifrous. These materials
are chemically combined through preprocessing and subjected to subsequent mechanical processing
operations to form gray and white portland cement. Gray portland cement is used for structural
applications and is the more common type of cement produced. White portland cement has lower iron and
manganese contents than gray portland cement and is used primarily for decorative purposes. Portland
cement manufacturing plants are part of hydraulic cement manufacturing, which also includes natural,
masonry, and pozzolanic cement. The six-digit Source Classification Code (SCC) for portland cement
plants with wet process kilns is 3-05-006, and the six-digit SCC for plants with dry process kilns is 3-05-
007.
Portland cement accounts for 95 percent of the hydraulic cement production in the United States.
The balance of domestic cement production is primarily masonry cement. Both of these materials are
produced in portland cement manufacturing plants. A diagram of the process, which encompasses
production of both portland and masonry cement, is shown in Figure 11.6-1
EMISSION FACTORS 1/95
-------
PM EMISSIONS
© GASEOUS EMISSIONS
OPTIONAL PROCESS STEP
0
(2J
4
OPTIONAL
PREHEATER/
PRECALCINER
®
DRY PROCESS
0
*
QUARRYING
RAW
MATERIALS
1
r |
OPTIONAL
PREHEATER
©
PROCESSING RAW
MATERIALS (PRIMARY
AND SECONDARY
CRUSHING)
EMISSION SOURCE
SCC
Dry process-general ; 3-05-006-
Wet process-general 3-05-007-
A. Kiln -06
B. Raw material unloading -07
C. Raw material pies -08
D. Primary crushing -09
E. Secondary crushing -10
F. Screening .11
G. Raw material transfer -12
H. Raw material grinding/drying -13
I. Clinker cooler -14
J. Clinker piles .15
K. Clinker transfer -16
L. Clinker grinding -17
M. Cement silos -18
N. Cement toad out -19
O. Raw ml feed belt -24
P. Raw mill weigh hopper .25
Q. Raw mlK air separator .26
R. Finish grinding mil feed belt .27
3. Finish grinding mHI weigh hopper .28
T. Finish grinding mM air separator .39
U. Preheater Mln 3-05-006-22
V. Preheater/precalclner kiln 3-05-006-22
GYPSUM
ii i>
ROTARY CLINKER
KILN > COOLER
® ©
I
R
i
JEL
w
CLINKER
STORAGE
Q)
V
i
-------
. As shown in the figure, the process can be divided into the following primary components: raw
materials acquisition and handling, kiln feed preparation, pyroprocessing, and finished cement grinding.
Each of these process components is described briefly below. The primary focus of this discussion is on
pyroprocessing operations, which constitute the core of a portland cement plant.
The initial production step hi portland cement manufacturing is raw materials acquisition.
Calcium, the element of highest concentration in portland cement, is obtained from a variety of calcareous
raw materials, including limestone, chalk, marl, sea shells, aragonite, and an impure limestone known as
"natural cement rock". Typically, these raw materials are obtained from open-face quarries, but
underground mines or dredging operations are also used. Raw materials vary from facility to facility.
Some quarries produce relatively pure limestone mat requires the use of additional raw materials to
provide the correct chemical blend in the raw mix. In other quarries, all or part of the noncalcarious
constituents are found naturally in the limestone. Occasionally, pockets of pyrite, which can significantly
increase emissions of sulfur dioxide (SOJ, are found in deposits of limestone, clays, and shales used as
raw materials for portland cement. Because a large fraction (approximately one third) of the mass of this
primary material is lost as carbon dioxide (COj) in the kiln, portland cement plants are located close to a
calcareous raw material source whenever possible. Other elements included hi the raw mix are silicon,
aluminum, and iron. These materials are obtained from ores and minerals such as sand, shale, clay, and
iron ore. Again, these materials are most commonly from open-pit quarries or mines, but they may be
dredged or excavated from underwater deposits.
Either gypsum or natural anhydrite, both of which are forms of calcium sulfate, is introduced to
the process during the finish grinding operations described below. These materials, also excavated from
quarries or mines, are generally purchased from an external source, rather than obtained directly from a
captive operation by the cement plant. The portland cement manufacturing industry is relying increasingly
on replacing virgin materials with waste materials or byproducts from other manufacturing operations, to
the extent that such replacement can be implemented without adversely affecting plant operations, product
quality or the environment. Materials that have been used include fly ash, mill scale, and metal smelting
slags.
The second step in portland cement manufacture is preparing the raw mix, or kiln feed, for the
pyroprocessing operation. Raw material preparation includes a variety of blending and sizing operations
that are designed to provide a feed with appropriate chemical and physical properties. The raw material
processing operations differ somewhat for wet and dry processes, as described below.
Cement raw materials are received with an initial moisture content varying from 1 to more than
50 percent. If the facility uses dry process kilns, this moisture is usually reduced to less than 1 percent
before or during grinding. Drying alone can be accomplished in impact dryers, drum dryers, paddle-
equipped rapid dryers, air separators, or autogenous mills. However, drying can also be accomplished
during grinding in ball-and-tube mills or roller mills. While thermal energy for drying can be supplied by
exhaust gases from separate, direct-fired coal, oil, or gas burners, the most efficient and widely used
source of heat for drying is the hot exit gases from the pyroprocessing system.
Materials transport associated with dry raw milling systems can be accomplished by a variety of
mechanisms, including screw conveyors, belt conveyors, drag conveyors, bucket elevators, air slide
conveyors, and pneumatic conveying systems. The dry raw mix is pneumatically blended and stored in
specially constructed silos until it is fed to the pyroprocessing system.
In the wet process, water is added to the raw mill during the grinding of the raw materials in ball
or tube mills, thereby producing a pumpable slurry, or slip, of approximately 65 percent solids. The
11-6-4 EMISSION FACTORS 1/95
-------
slurry is agitated, blended, and stored in various kinds and sizes of cylindrical tanks or slurry basins until it
is fed to the pyroprocessing system.
The heart of the portland cement manufacturing process is the pyroprocessing system. This
system transforms the raw mix into clinkers, which are gray, glass-hard, spherically shaped nodules that
range from 0.32 to 5. 1 centimeters (cm) (0. 125 to 2.0 inches [in.]) in diameter. The chemical reactions
and physical processes that constitute the transformation are quite complex, but they can be viewed
conceptually as the following sequential events:
1 . Evaporation of free water;
f
2. Evolution of combined water in the argillaceous components;
3. Calcination of the calcium carbonate (CaCO3) to calcium oxide (CaO);
4. Reaction of CaO with silica to form dicalcium silicate;
5. Reaction of CaO with the aluminum and iron-bearing constituents to form the liquid
phase;
6. Formation of the clinker nodules;
7. Evaporation of volatile constituents (e. g., sodium, potassium, chlorides, and sul fates);
and
8. Reaction of excess CaO with dicalcium silicate to form tricalcium silicate.
This sequence of events may be conveniently divided into four stages, as a function of location and
temperature of the materials in the rotary kiln.
1 . Evaporation of uncombined water from raw materials, as material temperature increases to
100°C (212°F);
2. Dehydration, as the material temperature increases from 100°C to approximately 430°C
(800 °F) to form oxides of silicon, aluminum, and iron;
3. Calcination, during which carbon dioxide (COz) is evolved, between 900°C (1650°F) and
982 °C (1800°F), to form CaO; and
4. Reaction, of the oxides in the burning zone of the rotary kiln, to form cement clinker at
temperatures of approximately 1510°C (2750°F).
Rotary kilns are long, cylindrical, slightly inclined furnaces that are lined with refractory to
protect the steel shell and retain heat within the kiln. The raw material mix enters the kiln at the elevated
end, and the combustion fuels generally are introduced into the lower end of the kiln in a countercurrent
manner. The materials are continuously and slowly moved to the lower end by rotation of the kiln. As
they move down the kiln, the raw materials are changed to cementitious or hydraulic minerals as a result
of the increasing temperature within the kiln. The most commonly used kiln fuels are coal, natural gas,
and occasionally oil. The use of supplemental fuels such as waste solvents, scrap rubber, and petroleum
coke has expanded in recent years.
1195 Mineral Products Industry 11.6-5
-------
Five different processes are used in the portland cement industry to accomplish the pyroprocessing
step: the wet process, the dry process Gong dry process), the semidry process, the dry process with a
preheater, and the dry process with a preheater/precalciner. Each of these processes accomplishes the
physical/chemical steps defined above. However, the processes vary wife respect to equipment design,
method of operation, and fuel consumption. Generally, fuel consumption decreases in the order of the
processes listed. The paragraphs below briefly describe the process, starting with the wet process and then
noting differences in the other processes.
In the wet process and long dry process, all of the pyroprocessing activity occurs in the rotary
kiln. Depending on the process type, kilns have length-to-diameter ratios in the range of 15:1 to 40:1.
While some wet process kilns may be as long as 210 m (700 ft), many wet process kilns and all dry
process kilns are shorter. Wet process and long dry process pyroprocessing systems consist solely of the
simple rotary kiln. Usually, a system of chains is provided at the feed end of the kiln in the drying or
preheat zones to improve heat transfer from the hot gases to the solid materials. As the kiln rotates, the
chains are raised and exposed to the hot gases. Further kiln rotation causes the hot chains to fall into the
cooler materials at the bottom of the kiln, thereby transferring the heat to the load.
Dry process pyroprocessing systems have been improved hi thermal efficiency and productive
capacity through the addition of one or more cyclone-type preheater vessels in the gas stream exiting the
rotary kiln. This system is called the preheater process. The vessels are arranged vertically, in series, and
are supported by a structure known as the preheater tower. Hot exhaust gases from the rotary kiln pass
counter currently through the downward-moving raw materials in the preheater vessels. Compared to the
simple rotary kiln, the heat transfer rate is significantly increased, the degree of heat utilization is greater,
and the process time is markedly reduced by the intimate contact of the solid particles with the hot gases.
The improved heat transfer allows the length of the rotary kiln to be reduced. The hot gases from the
preheater tower are often used as a source of heat for drying raw materials in the raw mill. Because the
catch from the mechanical collectors, fabric filters, and/or electrostatic precipitators (ESP) that follow the
raw mill is returned to the process, these devices are considered to be production machines as well as
pollution control devices.
Additional thermal efficiencies and productivity gains have been achieved by diverting some fuel
to a calciner vessel at the base of the preheater tower. This system is called the preheater/precalciner
process. While a substantial amount of fuel is used in the precalciner, at least 40 percent of the thermal
energy is required in the rotary kiln. The amount of fuel that is introduced to the calciner is determined by
the availability and source of the oxygen for combustion in the calciner. Calciner systems sometimes use
lower-quality fuels (e. g., less-volatile matter) as a means of improving process economics.
Preheater and precalciner kiln systems often have an alkali bypass system between the feed end of
the rotary kiln and the preheater tower to remove the undesirable volatile constituents. Otherwise, the
volatile constituents condense in the preheater tower and subsequently recirculate to the kiln. Buildup of
these condensed materials can restrict process and gas flows. The alkali content of portland cement is
often limited by product specifications because excessive alkali metals (i. e., sodium and potassium) can
cause deleterious reactions in concrete. In a bypass system, a portion of the kiln exit gas stream is
withdrawn and quickly cooled by air or water to condense the volatile constituents to fine particles. The
solid particles, containing the undesirable volatile constituents, are removed from the gas stream and thus
the process by fabric filters and ESPs.
The semidry process is a variation of the dry process. In the semidry process, the water is added
to the dry raw mix in a pelletizer to form moist nodules or pellets. The pellets then are conveyed on a
moving grate preheater before being fed to the rotary kiln. The pellets are dried and partially calcined by
hot kiln exhaust gases passing through the moving grate.
H-6-6 EMISSION FACTORS 1795
-------
Regardless of the type of pyroprocess used, the last component of the preprocessing system is the
clinker cooler. This process step recoups up to 30 percent of the heat input to the kiln system, locks in
desirable product qualities by freezing mineralogy, and makes it possible to handle the cooled clinker with
conventional conveying equipment. The more common types of clinker coolers are (1) reciprocating
grate, (2) planetary, and (3) rotary. In these coolers, the clinker is cooled from about 1100°C to 93°C
(2000°F to 200°F) by ambient air mat passes through the clinker and into the rotary kiln for use as
combustion air. However, in the reciprocating grate cooler, lower clinker discharge temperatures are
achieved by passing an additional quantity of air through the clinker. Because this additional air cannot be
utilized hi the kiln for efficient combustion, it is vented to the atmosphere, used for drying coal or raw
materials, or used as a combustion air source for the precalciner.
The final step hi portiand cement manufacturing.involves a sequence of blending and grinding
operations mat transforms clinker to finished portiand cement. Up to 5 percent gypsum or natural
anhydrite is added to the clinker during grinding to control the cement setting time, and other specialty
chemicals are added as needed to impart specific product properties. This finish milling is accomplished
almost exclusively hi ball or tube nulls. Typically, finishing is conducted hi a closed- circuit system, with
product sizing by air separation.
11.6.2 Emissions And Controls1-3"7
Paniculate matter (PM and PM-10), nitrogen oxides (NOJ, sulfur dioxide (SOJ, carbon
monoxide (CO), and CO2 are the primary emissions in the manufacture of portiand cement. Small
quantities of volatile organic compounds (VOC), ammonia (NH3), chlorine, and hydrogen chloride (HC1),
also may be emitted. Emissions may also include residual materials from the fuel and raw materials or
products of incomplete combustion that are considered to be hazardous. Because some facilities burn
waste fuels, particularly spent solvents hi the kiln, these systems also may emit small quantities of
additional hazardous organic pollutants. Also, raw material feeds and fuels typically contain trace amounts
of heavy metals that may be emitted as a particulate or vapor.
Sources of PM at cement plants include (1) quarrying and crushing, (2) raw material storage, (3)
grinding and blending (in the dry process only), (4) clinker production, (5) finish grinding, and
(6) packaging and loading. The largest emission source of PM within cement plants is the pyroprocessing
system that includes the kiln and clinker cooler exhaust stacks. Often, dust from the kiln is collected and
recycled into the kiln, thereby producing clinker from the dust. However, if the alkali content of the raw
materials is too high, some or all of the dust is discarded or leached before being returned to the kiln. In
many instances, the maximum allowable cement alkali content of 0.6 percent (calculated as sodium oxide)
restricts the amount of dust that can be recycled. Bypass systems sometimes have a separate exhaust stack.
Additional sources of PM are raw material storage piles, conveyors, storage silos, and unloading facilities.
Emissions from portiand cement plants constructed or modified after August 17, 1971 are regulated to
limit PM emissions from portiand cement kilns to 0.15 kg/Mg (0.30 Ib/ton) of feed (dry basis), and to limit
PM emissions from clinker coolers to 0.050 kg/Mg (0.10 Ib/ton) of feed (dry basis).
Oxides of nitrogen are generated during fuel combustion by oxidation of chemically-bound
nitrogen in the fuel and by thermal fixation of nitrogen in the combustion air. As flame temperature
increases, the amount of thermally generated NOX increases. The amount of NOX generated from fuel
increases with the quantity of nitrogen in the fuel. In the cement manufacturing process, NOX is generated
in both the burning zone of the kiln and the burning zone of a precalcining vessel. Fuel use affects the
quantity and type of NO, generated. For example, in the kiln, natural gas combustion with a high flame
temperature and low fuel nitrogen generates a larger quantity of NO, than does oil or coal, which have
higher fuel nitrogen but which burn with lower flame temperatures. The opposite may be true in a
precalciner. Types of fuels used vary across the industry. Historically, some combination of coal, oil,
1 /95 Mineral Products Industry 11.6-7
-------
and natural gas was used, but over the last 15 years, most plants have switched to coal, which generates
less NO, man does oil or gas. However, in recent years a number of plants have switched to systems that
burn a combination of coal and waste fuel. The effect of waste fuel use on NO, emissions is not clearly
established.
Sulfur dioxide may be generated both from the sulfur compounds in the raw materials and from
sulfur in the fuel. The sulfur content of bom raw materials and fuels varies from plant to plant and with
geographic location. However, the alkaline nature of the cement provides for direct absorption of SO2 into
the product, thereby mitigating the quantity of SO2 emissions in the exhaust stream. Depending on the
process and the source of the sulfur, SO2 absorption ranges from about 70 percent to more than 95
percent.
The CO2 emissions from portland cement manufacturing are generated by two mechanisms. As
with most high-temperature, energy-intensive industrial processes, combusting fuels to generate process
energy releases substantial quantities of CO2. Substantial quantities of CO2 also are generated through
calcining of limestone or other calcareous material. This calcining process thermally decomposes CaCO3
to CaO and CO2. Typically, portland cement contains the equivalent of about 63.5 percent CaO.
Consequently, about 1.135 units of CaCO3 are required to produce 1 unit of cement, and the amount of
CO2 released in the calcining process is about 500 kilograms (kg) per Mg of portland cement produced
(1,000 pounds [Ib] per ton of cement). Total CO2 emissions from the pyroprocess depend on energy
consumption and generally fall in the range of 0.85 to 1.35 Mg of CO2 per Mg of clinker.
In addition to CO2 emissions, fuel combustion at portland cement plants can emit a wide range of
pollutants in smaller quantities. If the combustion reactions do not reach completion, CO and volatile
organic pollutants, typically measured as total organic compounds (TOC), VOC, or organic condensable
paniculate, can be emitted. Incomplete combustion also can lead to emissions of specific hazardous
organic air pollutants, although these pollutants are generally emitted at substantially lower levels than CO
or TOC.
Emissions of metal compounds from portland cement kilns can be grouped into three general
classes: volatile metals, including mercury (Hg) and thallium (Tl); semivolatile metals, including antimony
(Sb), cadmium (Cd), lead (Pb), selenium (Se), zinc (Zn), potassium (K), and sodium (Na); and refractory
or nonvolatile metals, including barium (Ba), chromium (Cr), arsenic (As), nickel (Ni), vanadium (V),
manganese (Mn), copper (Cu), and silver (Ag). Although the partitioning of these metal groups is affected
by kiln operating conditions, the refractory metals tend to concentrate in the clinker, while the volatile and
semivolatile metals tend to be discharged through the primary exhaust stack and the bypass stack,
respectively.
Fugitive dust sources in the industry include quarrying and mining operations, vehicle traffic
during mineral extraction and at the manufacturing site, raw materials storage piles, and clinker storage
piles. The measures used to control emissions from these fugitive dust sources are comparable to those
used throughout the mineral products industries. Vehicle traffic controls include paving and road wetting.
Controls that are applied to other open dust sources include water sprays with and without surfactants,
chemical dust suppressants, wind screens, and process modifications to reduce drop heights or enclose
storage operations. Additional information on these control measures can be found in Chapter 13 of AP-
42, "Miscellaneous Sources".
Process fugitive emission sources include materials handling and transfer, raw milling operations
in dry process facilities, and finish milling operations. Typically, emissions from these processes are
captured by a ventilation system and collected in fabric filters. Some faculties use an air pollution control
system comprising one or more mechanical collectors with a fabric filter in series. Because the dust from
H-6-8 EMISSION FACTORS 1/95
-------
these units is returned to the process, mey are considered to be process units as well as air pollution control
devices. The industry uses shaker, reverse air, and pulse jet filters as well as some cartridge units, but
most newer facilities use pulse jet filters. For process fugitive operations, the different systems are
reported to achieve typical outlet PM loadings of 45 milligrams per cubic meter (mg/m3) (0.02 grains per
actual cubic foot [gr/acfj).
In the pyroprocessing units, PM emissions are controlled by fabric filters (reverse air, pulse jet, or
pulse plenum) and electrostatic precipitators (ESP). Typical control measures for the kiln exhaust are
reverse air fabric filters with an air-to-cloth ratio of 0.41:1 m3/min/m2 (1.5:1 acfm/ft2) and ESP with a net
surface collection area of 1,140 to 1,620 m2/l,000 m3 (350 to 500 ftVl.OOO ft3). These systems are
reported to achieve outlet PM loadings of 45 mg/m3 (0.02 gr/acf). Clinker-cooler systems are controlled
most frequently with pulse jet or pulse plenum fabric filters. A few gravel bed filters also have been used
to control clinker cooler emissions. Typical outlet PM loadings are identical to those reported for kilns.
Cement kiln systems have highly alkaline internal environments that can absorb up to 95 percent of
potential SO2 emissions. However, hi systems mat have sulfide sulfur (pyrites) in the kiln feed, the sulfur
absorption rate may be as low as 70 percent without unique design considerations or changes in raw
materials. The cement kiln system itself has been determined to provide substantial SO2 control. Fabric
filters on cement kilns are also reported to absorb SO2. Generally, substantial control is not achieved. An
absorbing reagent (e. g., CaO) must be present in the filter cake for SO2 capture to occur. Without the
presence of water, which is undesirable in the operation of a fabric filter, CaCO3 is not an absorbing
reagent. It has been observed that as much as 50 percent of the SO2 can be removed from the
pyroprocessing system
exhaust gases when mis gas stream is used in a raw mill for heat recovery and drying. In this case,
moisture and calcium carbonate are simultaneously present for sufficient time to accomplish the chemical
reaction with
SO2. Tables 11.6-land 11.6-2 present emission factors for PM emissions from portland cement
manufacturing kilns and clinker coolers. Tables 11.6-3 and 11.6-4 present emission factors for PM
emissions from raw material and product processing and handling. Particle size distributions for emissions
from wet process and dry process kilns are presented in Table 11.6-5, and Table 11.6-6 presents the
particle size distributions for emissions from clinker coolers. Emission factors for SO2, NO,, CO, CO2,
and TOC emissions from portland cement kilns are summarized in Tables 11.6-7 and 11.6-8.
Table 11.6-9 summarizes emission factors for other pollutant emissions from portland cement kilns.
Because of differences in the sulfur content of the raw material and fuel and in process operations, a mass
balance for sulfur may yield a more representative emission factor for a specific facility than the SO2
emission factors presented in Tables 11.6-7 and 11.6-8. In addition, CO2 emission factors estimated using
a mass balance on carbon may be more representative for a specific facility man the CO2 emission factors
presented in Tables 11.6-7 and 11.6-8. S
1 /95 Mineral Products Industry 11.6-9
-------
Table 11.6-2 (cont.).
Process
Clinker cooler with ESP
(SCC 3-05-006-14)
Clinker cooker with fabric filter
(SCC 3-05-006-14)
Clinker cooler with gravel bed filter
(SCC 3-05-006-14)
Filterable"
EMISSION
FACTOR
PM RATING
0.096" D
0.131' D
0.21" D
PM-10
ND
ND
0.16
EMISSION
FACTOR
RATING .
» D
Condensable0
Inorganic
0.0075
0.017
0.0090
EMISSION
FACTOR
RATING
D
D
- D
Organic
NET
ND
ND
EMISSION
FACTOR
RATING
VI
I
I
Classification Code. ND = no data. ESP = electrostatic precipitator.
Filterable PM is that collected on or before the filter of an EPA Method 5 (or equivalent) sampling train.
Condensable PM is that collected in the impinger portion of a PM sampling train.
References 20,26.
References 3,20,26.
References 8-9,18,20,25-26,32,34-36,41-44,60,64.
References 3,8-9,18,20,25-26,32,34-36,41-44,60,64.
References 8-9,20,64.
Reference 14.
Reference 21.
References 19,21.
Reference 23.
References 3,23.
Reference 17.
Reference 31.
References 17,47-50,61.
Reference 51.
Reference 37.
References 30,33,51,56-59,63
References 30,33,37,51,59.
References. y References 9,12,27,30,33.
-------
Table 11.6-3 (Metric Units). EMISSION FACTORS FOR PORTLAND CEMENT
MANUFACTURING RAW MATERIAL AND PRODUCT PROCESSING AND HANDLING'
Process
Raw mill with fabric filter
(SCC 3-05-006-13)
Raw mill feed belt with fabric filter
(SCC 3-05-006-24)
Raw mill weigh hopper with fabric filter
(SCC 3-05-006-25)
Raw mill air separator with fabric filter
(SCC 3-05-006-26)
Finish grinding mill with fabric filter
(SCC 3-05-006-17, 3-05-007-17)
Finish grinding mill feed belt with fabric filter
(SCC 3-05-006-27, 3-05-007-27)
Finish grinding mill weigh hopper with fabric filter
(SCC 3-05-006-28, 3-05-007-28)
Finish grinding mill air separator with fabric filter
(SCC 3-05-006-29, 3-05-007-29)
Primary limestone crushing with fabric filter
(SCC 3-05-006-09)h
Primary limestone screening with fabric filter
(SCC 3-05-006- 11 )h
Limestone transfer with fabric filter
(SCC 3-05-006-12)h
Secondary limestone screening and crushing with
fabric filter
(SCC 3-05-006-10 + -11, 3-05-007-10 + -1 l)h
PM
0.0062C
0.00 16d
0.010*
0.016'
0.0042f
0.00 12d
0.0047'
0.014*
0.00050
0.00011
1.5xlO'5
0.00016
Filterableb
EMISSION
FACTOR
RATING
D
E
E
E
D
E
E
D
E
E
E
E
PM-10
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
EMISSION
FACTOR
RATING
erwise noted Factors ««
Factors represent uncontrolled emissions, unless oth1
unless noted. SCC = Source Classification Code. ND = no data.
material process,
Filterable PM is that collected on or before the filter of an EPA Method 5 (or equivalent) sampling train.
c References 15,56-57.
d Reference 57.
e Reference 15.
f References 10,12,15,56-57.
8 References 10,15.
h Reference 16. Alternatively, emission factors from Section 11.19.2, "Crushed Stone Processing", can be
used for similar processes and equipment.
1/95
Mineral Products Industry
11.6-11
-------
Table 11.6-4 (English Units). EMISSION FACTORS FOR PORTLAND CEMENT
MANUFACTURING RAW MATERIAL AND PRODUCT PROCESSING AND HANDLING'
Process
Raw mill with fabric filter
(SCC 3-05-006-13)
Raw mill feed belt with fabric filter
(SCC 3-05-006-24)
Raw mill weigh hopper with fabric filter
(SCC 3-05-006-25)
Raw mill air separator with fabric filter
(SCC 3-05-006-26)
Finish grinding mill with fabric filter
(SCC 3-05-006-17, 3-05-007-17)
Finish grinding mill feed belt with fabric filter
(SCC 3-05-006-27, 3-05-007-27)
Finish grinding mill weigh hopper with fabric filter
(SCC 3-05-006-28, 3-05-007-28)
Finish grinding mill air separator with fabric filter
(SCC 3-05-006-29, 3-05-007-29)
Primary limestone crushing with fabric filter
(SCC 3-05-006-09)"
Primary limestone screening with fabric filter
(SCC'3 -05-006- ll)h
Limestone transfer with fabric filter
(SCC 3-05-006- 12)h
Secondary limestone screening and crushing with
fabric filter
(SCC 3-05-006-10 + -1 1, 3-05-007-10 + -1 l)h
PM
0.0 12C
0.0031"
0.019'
0.032«
0.0080f
0.0024d
0.0094'
0.028'
0.0010
0.00022
2.9 x I O'3
0.00031
Filterable"
EMISSION
FACTOR
RATING
D
E
E
E
E
E
E
D
E
E
E
E
PM-10
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
EMISSION
FACTOR
RATING
a Factors represent uncontrolled emissions, uniess other™845 noted- Factors are Ib/ton of material processed,
unless noted. SCC = Source Classification Code. ND = no data.
b Filterable PM is that collected on or before the filter of an EPA Method 5 (or equivalent) sampling train
c References 15,56-57.
d Reference 57.
c Reference 15.
{ References 10,12,15,56-57.
g References 10,15.
h Reference 16. Alternatively, emission factors from the Section 11.19.2, "Crushed Stone Processing", can
be used for similar processes and equipment.
11.6-12
EMISSION FACTORS
1/95
-------
Table 11.6-5. SUMMARY OF AVERAGE PARTICLE SIZE DISTRIBUTION
FOR PORTLAND CEMENT KILNS1
Particle
Size, uin
2.5
5.0
10.0
15.0
20.0
Cumulative Mass Percent Equal To Or Less Than Stated Size
Uncontrolled
Wet process
(SCC 3-05-007-06)
7
20
24
35
57
Dry process
(SCC 3-05-006-06)
18
ND
42
44
ND
Controlled
Wet process
With ESP
(SCC 3-05-007-06)
64
83
85
91
98
Dry process
WithFF
(SCC 3-05-006-06)
45
77
84
89
100
• References. SCC = Source Classification Code ND = nodata.
Table 11.6-6. SUMMARY OF AVERAGE PARTICLE SIZE DISTRIBUTION
FOR PORTLAND CEMENT CLINKER COOLERS'
Particle Size, urn
2.5
5.0
10.0
15.0
20.0
Cumulative Mass Percent Equal To Or Less Than Stated Size
Uncontrolled
(SCC 3-05-006-14, 3-05-007-14)
0.54
1.5
8.6
21
34
With Gravel Bed Filter
(SCC 3-05-006-14, 3-05-007-14)
40
64
76
84
89
Reference 3. SCC = Source Classification Code.
1/95
Mineral Products Industry
11.6-13
-------
Table 11.6-7 (Metric Units). EMISSION FACTORS FOR PORTLAND CEMENT MANUFACTURING"
Process
Wet process kiln
(SCC 3-05-007-06)
Long dry process kiln
(SCC 3-05-006-06)
Preheater process kiln
(SCC 3-05-006-22)
Preheater/precalciner kiln
(SCC 3-05-006-23)
Preheater/precalciner kiln with
spray tower
(SCC 3-05-006-23)
SO
4.1d
4.9"
Q.2T
0.54"
0.501
EMISSION
FACTOR
RATING
C
D
D
D
E
2b NO
3.7
3.0
2.4
2.1
ND
EMISSION
FACTOR
RATING
e D
' D
' D
y D
CO
0.060
0.11
0.49
1.8
ND
EMISSION
FACTOR
RATING
' D,
* E
' D
" D
CO
1,100
900
900
900
ND
EMISSION
FACTOR
RATING
• D
• D
• c
1 E
I
TOC
0.014
0.014
0.090
0.059
ND
EMISSION
FACTOR
RATING
' D
" E
' D
' D
§
. Factors represent uncontrolled emissions unless otherwise noted. Factors are kg/Mg of clinker produced, unless noted. SCC = Source
Classification Code. ND = no data.
b Mass balance on sulfur may yield a more representative emission factor for a specific facility than the SO 2emission factors presented in this
table.
c Mass balance on carbon may yield a more representative emission factor for a specific facility than the CO 2emission factors presented in this
table.
d References 20,25-26,32,34-36,41-44,60,64.
e References 26,34-36,43,64.
' Reference 64.
• References 25-26,32,34-36,44,60,64.
h References 11,19,39,40.
' References 11,38-40,65.
k References 39,65.
m References 11,21,23,65.
" References 40,65. TOC as measured by Method 25A or equivalent.
p References 47-50.
' References 48-50.
-------
VO
Table 11.6-8 (English Units). EMISSION FACTORS FOR PORTLAND CEMENT MANUFACTURING'
Process
Wet process kiln
(SCC 3-05-007-06)
Long dry process kiln
(SCC 3-05-006-06)
Preheater process kiln
(SCC 3-05-006-22)
Preheater/precalciner kiln
(SCC 3-05-006-23)
Preheater/precalciner kiln
with spray tower
(SCC 3-05-006-23)
SO
8.2"
10"
0.55P
1.1"
l.O1
EMISSION
FACTOR
RAT1NC?
C
D
D
D
E
NO
7.4
6.0
4.8
4.2
ND
EMISSION
FACTOR
RATJNG
e D
J D
' D
' D
CO
0.12
0.21
0.98
3.7
ND
EMISSION
FACTOR
RATING
' D
*E
'D
w D
CO
2,100
1,800
ND
EMISSION
FACTOR
RATING
• D
D
C
1 E
TOC
0.028
0.028
0.18
0.12
ND
EMISSION
FACTOR
RATING
to
•E
1 D
' D
Factors represent uncontrolled emissions unless otherwise no ted. Factors are Ib/ton of clinker produced, unless noted.
SCC = Source Classification Code. ND = no data.
* Mass balance on sulfur may yield a more representative emission factor for a specific facility than the SO 2emission factors presented in this
table.
0 Mass balance on carbon may yield a more representative emission factor for a specific facility than the CO 2emission factors presented in this
table.
d References 20,25-26,32,34-36,41-44,60,64.
• References 26,34-36,43,64.
' Reference 64. i
1 References 25-26,32,34-36,44,60,64.
k References 11,19,39-40.
j References 11,38-40,65.
k References 39,65.
"References 11,21,23,65.
* References 40,65. TOC as measured by Method 25A or equivalent.
f References 47-50.
q References 48-50.
r Reference 49.
-------
Table 11.6-8 (cont.).
References 28,30,33,37,53,56-59.
References 28,30,33,37,45, and 56 to 59.
References 28,30,37,56-58,63.
References 24,31,47-50,61. Based on test data for preheater kilns; should be considered an upper limit.
References 30,33,56,63; total organic compounds as measured using Method 25A or equivalent.
Reference 54.
I
-------
Table 11.6-9 (Metric And English Units). SUMMARY OF NONCRTTERIA POLLUTANT
EMISSION FACTORS FOR PORTLAND CEMENT KILNS'
(SCC 3-05-006-06,3-05-007-06,3-05-006-22,3-05-006-23)
Pollutant
Name
Type Of
Control
Average Emission Factor
kj?/M«
Inorganic Pollutants
Silver (Ag)
Aluminum (Al)
Arsenic (As)
Arsenic (As)
Barium (Ba)
Barium (Ba)
Beryllium (Be)
Calcium (Ca)
Cadmium (Cd)
Cadmium (Cd)
Chloride (Cl)
Chloride (Cl)
Chromium (Cr)
Chromium (Cr)
Copper (Cu)
Fluoride (F)
Iron (Fe)
Hydrogen chloride (HC1)
Hydrogen chloride (HCI)
Mercury (Hg)
Mercury (Hg)
Potassium (K)
Manganese (Mn)
Ammonia (NH3)
Ammonium (NH,)
Nitrate (NO3)
Sodium (Na)
Lead(Pb)
Lead (Pb)
Sulfur tnoxide (SO3)
Sulfur trioxide (SO3)
Sulfate (SO4)
Sulfate (SO,)
FF
ESP
ESP
FF
ESP
FF
FF
ESP
ESP
FF
ESP
FF
ESP
FF
FF
ESP
ESP
ESP
FF
ESP
FF
ESP
ESP
FF
ESP
ESP
ESP
ESP
FF
ESP
FF
ESP
FF
S.lxlO'7
0.0065
6.5x10-*
6-OxlO-6
0.00018
0.00023
3.3xlO'7
0.12
4-2X10-*
1.1x10-*
0.34
0.0011
3.9x10-*
7.0xlO-3
0.0026
0.00045
0.0085
0.025
0.073
0.00011
1.2xlO-5
0.0090
0.00043
0.0051
0.054
0.0023
0.020
0.00036
3.8x1 0'5
0.042
0.0073
0.10
0.0036
Ib/ton
EMISSION
FACTOR
RATING
References
6-lxlO'7
0.013
1.3xlO's
1.2X10'5
0.00035
0.00046
6.6x10-'
0.24
8.3x10-*
2.2x10-*
0.68
0.0021
7.7x10"*
0.00014
0.0053
0.00090
0.017
0.049
0.14
0.00022
2.4xlO'5
0.018
0.00086
0.010
0.11
0.0046
0.038
0.00071
7.5x1 0-5
0.086
0.014
0.20
0.0072
D
E
E
D
D
D
D
E
D
D
E
D
E
D
E
E
E
E
D
D
D
D
E
E
D
E
D
D
D
E
D
D
D
63
65
65
63
64
63
63
65
64
63
25.42-W
63
64
63
62
43
65
41,65
59,63
64
11.63
25,42-43
65
59
25,42-44
43
25,42-44
64
63
25
2430,50
25,42-44
3033,52
1/95
Mineral Products Industry
11.6-17
-------
Table 11.6-9 (com.).
Pollutant
Name
Selenium (Se)
Selenium (Se)
Thallium (Th)
Titanium (Ti)
Zinc (Zn)
Zinc (Zn)
Type Of
Control
ESP
FF
FF
ESP
ESP
FF
Average Emission Factor
kg/Mg
7.5xlO'5
0.00010
2.7x10^
0.00019
0.00027
0.00017
Ib/ton
0.00015
0.00020
5.4x10-*
0.00037
0.00054
0.00034
EMISSION
FACTOR
RATING
E
E
D
E
D
D
References
65
62
63
65
64
63
Organic Pollutants
CASKN*
35822-46-9
208-96-8
67-64-1
100-52-7
71-43-2
71-43-2
50-32-8
205-99-2
191-24-2
207-08-9
65-85-0
95-52-4
117-81-7
74-83-9
75-15-0
108-90-7
74-87-3
218-01-9
84-74-2
53-70-3
101-41-4
206^4-0
86-73-7
50-00-0
Name
1,2,3,4,6,7,8 HpCDD
C3 benzenes
C4 benzenes
C6 benzenes
acenaphthylene
acetone
benzaldehyde
benzene
benzene
benzo(a)anthraccne
benzo(a)pyrene
benzo(b)fluoranthene
benzo(gji4)perylene
benzo(k)fluoranthene
benzole acid
biphenyl
bis(2-ethylhexyl)phthalate
bromomcthane
carbon disulfide
chlorobenzene
chloromcthane
chrysene
di-n-butylphthalate
dibcnz(aji)anthracene
ethyl benzene
fluoranthene
fluorcne
formaldehyde
FF
ESP
ESP
ESP
FF
ESP
ESP
ESP
FF
FF
FF
FF
FF
FF
ESP
ESP
ESP
ESP
ESP
ESP
ESP
FF
ESP
FF
ESP
FF
FF
FF
l.lxlO'10
1.3x10-*
3.0x10-*
4.6xlO-7
5.9xlO'5
0.00019
1.2xlO-3
0.0016
0.0080
2.1x10-*
6.5x10"*
2.8x1 0'7
3.9x10-*
7.7x1 0-8
0.0018
S.lxlO"6
4.8xlO'3
2.2X10'5
5.5x1 0'3
8.0x10"*
0.00019
8.1x10-*
2.1xlO'3
3.1x10-'
9.5x10"*
4.4x10"*
9.4x10"*
0.00023
2.2xlO-10
2.6X10"6
6.0x1 0"*
9.2x10-'
0.00012
0.00037
2.4xlO'3
0.0031
0.016
4.3x10-*
1.3x10-'
5.6x10''
7.8x10"*
1.5x10-'
0.0035
6.1x10-*
9.5x1 0'3
4.3x1 0'5
0.00011
1.6xlO's
0.00038
1.6x10''
4.1xlO-5
6.3x10"'
1.9xlO'5
8.8x10"*
1.9xlO'5
0.00046
E
E
E
E
E
D
E
D
E
E
E
E
E
E
D
E
D
E
D
D
E
E
D
E
D
E
E
E
62
65
65
65
62
64
65
64
62
62
62
62
62
62
64
65
64
64
64
64
64
62
64
62
64
62
62
62
11.6-18
EMISSION FACTORS
1/95
-------
Table 11.6-9 (com.).
CASRN*
193-39-5
78-93-3
75-09-2
91-20-3
91-20-3
85-01-8
108-95-2
129-00-0
100-42-5
108-88-3
3268-87-9
132-64-9
132-64-9
1330-20-7
Pollutant
Name
frconllS
indcno(l ,23-cd)pyrcne
methyl ethyl ketone
methylenc chloride
mcthylnaphthalene
naphthalene
naphthalene
phenanthrene
phenol
pyrene
styrene
toluene
total HpCDD
total OCDD
total PCDD
total PCDF
total TCDF
xvlcnes
Type Of
Control
ESP
FF
"ESP
ESP
ESP
FF
ESP
FF
ESP
FF
ESP
ESP
FF
FF
FF
FF
FF
ESP
Average Emission Factor
kg/Mg
2.5xlO'J
4.3x10*
l.SxlO'5
0.00025
2.1X10-*
0.00085
0.00011
0.00020
5.5xlO'5
2-2X10-6
7.5x10''
0.00010
2.0xlO-'°
1.0x10-'
1.4x10"'
1.4x10-'°
1.4xlO-'°
6.5xlO'5
Ib/ton
S.OxlO-5
8.7x10-*
3.0xlO'5
0.00049
4.2x1 0-6
0.0017
0.00022
0.00039
0.00011
4.4x10-*
LSxlO-6
0.00019
3.9x10-'°
2.0x10"'
2.7x10''
2.9x10-'°
2.9x10-'°
0.00013
EMISSION
FACTOR
RATING
E
E
E
E
E
E
D
E
D
E
E
D
E
E
E
E
E
D
References
65
62
64-65
65
65
62
64
62
64
62
65
64
62
62
62
62
62
64
a Factors are kg/Mg and Ib/ton of clinker produced. SCC ~ Source Classification Code.
precipitator. FF = fabric filter.
b Chemical Abstract Service Registry Number (organic compounds only).
ESP = electrostatic
References For Section 11.6
1. W. L. Greer, et al., "Portland Cement", Air Pollution Engineering Manual, A. J. Buonicore and W.
T. Davis (eds.). Von Nostrand Reinhold, NY, 1992.
2. U. S. And Canadian Portland Cement Industry Plant Information Summary, December 31,1990,
Portland Cement Association, Washington, DC, August 1991.
3. J. S. Kinsey, Lime And Cement Industry - Source Category Report, Volume II, EPA-600/7-87-007,
U. S. Environmental Protection Agency, Cincinnati, OH, February 1987.
4. Written communication from Robert W. Crolius, Portland Cement Association, Washington, DC, to
Ron Myers, U. S. Environmental Protection Agency, Research Triangle Park, NC. March 11, 1992.
5. Written communication from Walter Greer, Ash Grove Cement Company, Overland Park, KS, to
Ron Myers, U. S. Environmental Protection Agency, Research Triangle Park, NC, September 30,
1993.
6. Written communication from John Wheeler, Capitol Cement, San Antonio, TX, to Ron Myers,
U. S. Environmental Protection Agency, Research Triangle Park, NC, September 21,1993.
1/95
Mineral Products Industry
11.6-19
-------
7. Written communication from F. L. Streitman, ESSROC Materials, Incorporated, Nazareth. PA, to
Ron Myers, U. S. Environmental Protection Agency, Research Triangle Park, NC, September 29,
1993.
8. Emissions From Wet Process Cement Kiln And Clinker Cooler At Maule Industries, Inc.. ETB Test
No. 71-MM-01, U. S. Environmental Protection Agency, Research Triangle Park, NC, March 1972.
9. Emissions From Wet Process Cement Kiln And Clinker Cooler At Ideal Cement Company. ETB
Test No. 71-MM-03, U. S. Environmental Protection Agency, Research Triangle Park, NC. March
1972.
10. Emissions From Wet Process Cement Kiln And Finish Mill Systems At Ideal Cement Company,
ETB Test No. 71-MM-04, U. S. Environmental Protection Agency, Research Triangle Park^ NC,
March 1972.
11. Emissions From Dry Process Cement Kiln At Dragon Cement Company, ETB Test No.
71-MM-05, U. S. Environmental Protection Agency, Research Triangle Park, NC, March 1972.
12. Emissions From Wet Process Clinker Cooler And Finish Mill Systems At Ideal Cement Company,
ETB Test No. 71-MM-06, U. S. Environmental Protection Agency, Research Triangle Park, NC,
March 1972.
13. Emissions From Wet Process Cement Kiln At Giant Portland Cement, ETB Test No. 71 -MM-07,
U. S. Environmental Protection Agency, Research Triangle Park, NC, March 1972.
14. Emissions From Wet Process Cement Kiln At Oregon Portland Cement, ETB Test No. 71-MM-15,
U. S. Environmental Protection Agency, Research Triangle Park, NC, March 1972.
15. Emissions From Dry Process Raw Mill And Finish Mill Systems At Ideal Cement Company, ETB
Test No. 71-MM-02, U. S. Environmental Protection Agency, Research Triangle Park, NC, April
1972.
16. Part I. Air Pollution Emission Test: Arizona Portland Cement, EPA Project Report No. 74-STN-l,
U. S. Environmental Protection Agency, Research Triangle Park, NC, June 1974.
17. Characterization Oflnhalable Paniculate Matter Emissions From A Dry Process Cement Plant,
EPA Contract No. 68-02-3158, Midwest Research Institute, Kansas City, MO, February 1983.
18. Characterization Oflnhalable Particulate Matter Emissions From A Wet Process Cement Plant,
EPA Contract No. 68-02-3158, Midwest Research Institute, Kansas City, MO, August 1983.
19. Particulate Emission Testing At Lone Star Industries'Nazareth Plant, Lone Star Industries, Inc.,
Houston, TX, January 1978.
20. Particulate Emissions Testing At Lone Star Industries' Greencastle Plant, Lone Star Industries,
Inc., Houston, TX, July 1977.
21. Gas Process Survey At Lone Star Cement, Inc. 's Roanoke No. 5 Kiln System, Lone Star Cement,
Inc., Cloverdale, VA, October 1979.
11.6-20 EMISSION FACTORS 1/95
-------
22. Test Report: Stack Analysis For Paniculate Emissions: Clinker Coolers/Gravel Bed Filter,
Mease Engineering Associates, Port Matilda, PA, January 1993.
23. Source Emissions Survey Of Oklahoma Cement Company's Kiln Number 3 Stack, Mullins
Environmental Testing Co., Inc., Addison, TX, March 1980.
24. Source Emissions Survey Of Lone Star Industries, Inc.: Kilns 1, 2, and 3, Mullins Environmental
Testing Co., Inc., Addison, TX, June 1980.
25. Source Emissions Survey Of Lone Star Industries, Inc., Mullins Environmental Testing Co.. Inc..
Addison, TX, November 1981.
26. Stack Emission Survey And Precipitator Efficiency Testing At Banner Springs Plant, Lone Star
Industries, Inc., Houston, TX, November 1981.
27. NSPSPaniculate Emission Compliance Test: No. 8 Kiln, Interpoll, Inc., Elaine, MN, March 1983.
28. Annual Compliance Test: Mojave Plant, Pape & Steiner Environmental Services, Bakersfield, CA,
May 1983.
29. Source Emissions Survey OfLehigh Portland Cement Company, Mullins Environmental Testing
Co., Inc., Addison, TX, August 1983.
30. Annual Compliance Test: Mojave Plant, Pape & Steiner Environmental Services, Bakersfield, CA,
May 1984.
31. Paniculate Compliance Test: Lehigh Portland Cement Company, CH2M Hill, Montgomery, AL,
October 1984.
32. Compliance Test Results: Particulate & Sulfur Oxide Emissions At Lehigh Portland Cement
Company, KVB, Inc., Irvine, CA, December 1984.
33. Annual Compliance Test: Mojave Plant, Pape & Steiner Environmental Services, Bakersfield, CA,
May 1985.
34. Stack Tests for Particulate, SO^ NOX And Visible Emissions At Lone Star Florida Holding, Inc.,
South Florida Environmental Services, Inc., West Palm Beach, FL, August 1985.
3 5. Compliance Stack Test At Lone Star Florida/Pennsuco, Inc., South Florida Environmental Services,
Inc., West Palm Beach, FL, July 1981.
36. Preliminary Stack Test At Lone Star Florida/Pennsuco, Inc., South Florida Environmental Services,
Inc., West Palm Beach, FL, July 1981.
37. Quarterly Testing For Lone Star Cement At Davensport, California, Pape & Steiner Environmental
Services, Bakersfield, CA, September 1985.
38. Written Communication from David S. Cahn, CalMat Co., El Monte, CA, to Frank Noonan, U. S.
Environmental Protection Agency, Research Triangle Park, NC, June 2,1987.
1/95 Mineral Products Industry 11.6-21
-------
39. Technical Report On The Demonstration Of The Feasibility OfNOx Emissions Reduction At
Riverside Cement Company, Crestmore Plant (Parts I-V), Riverside Cement Company, Riverside.
CA, and Quantitative Applications, Stone Mountain, GA, January 1986.
40. Emission Study Of The Cement Kiln No. 20 Baghouse Collector At The Alpena Plant, Great Lakes
Division, Lafarge Corporation, Clayton Environmental Consultants, Inc., Novi, MI, March 1989.
41. Baseline And Solvent Fuels Stack Emissions Test At Alpha Portland Cement Company In
Cementon, New York, Energy & Resource Recovery Corp., Albany, NY, January 1982.
42. Stationary Source Sampling Report Of Lone Star Industries, New Orleans, Louisiana, Entropy
Environmentalists, Inc., Research Triangle Park, NC, May 1982.
43. Stationary Source Sampling Report Of Lone Star Industries, New Orleans, Louisiana, Entropy
Environmentalists, Inc., Research Triangle Park, NC, May 1982.
44. Source Emissions Survey Of Kiln No. 1 At Lone Star Industries, Inc., New Orleans, Louisiana,
Mullins Environmental Testing Company, Inc., Addison, TX, March 1984.
45. Written Communication from Richard Cooke, Ash Grove Cement West Inc., Durkee, OR, to Frank
Noonan, U. S. Environmental Protection Agency, Research Triangle Park, NC, May 13, 1987.
46. Source Emissions Survey Of Texas Cement Company OfBuda, Texas, Mullins Environmental
Testing Co., Inc., Addison, TX, September 1986.
47. Determination ofParticulate and Sulfur Dioxide Emissions From The Kiln And Alkali Baghouse
Stacks At Southwestern Portland Cement Company, Pollution Control Science, Inc., Miamisburg,
OH, June 1986.
48. Written Communication from Douglas Maclver, Southwestern Portland Cement Company,
Victorville, CA, to John Groom, Quantitative Applications, Inc., Stone Mountain, GA, October 23,
1989.
49. Source Emissions Survey Of Southwestern Portland Cement Company, KOSMOS Cement
Division, MetCo Environmental, Dallas, TX, June 1989.
50. Written Communication from John Mummert, Southwestern Portland Cement Company, Amarillo,
TX, to Bill Stewart, Texas Air Control Board, Austin, TX April 14,1983.
51. Written Communication from Stephen Sheridan, Ash Grove Cement West, Inc., Portland, OR, to
John Croom, Quantitative Applications, Inc., Stone Mountain, GA, January 15, 1980.
52. Written Communication from David Cahn. CalMat Co., Los Angeles, CA, to John Croom,
Quantitative Applications, Inc., Stone Mountain, GA, December 18, 1989.
53. Source Emissions Compliance Test Report On The Kiln Stack AtMarquette Cement
Manufacturing Company, Cape Girardeau, Missouri, Performance Testing & Consultants, Inc.,
Kansas City, MO, February 1982.
54. Assessment Of Sulfur Levels At Lone Star Industries In Cape Girardeau, Missouri, KVB,
Elmsford, NY, January 1984.
11.6-22 EMISSION FACTORS 1/95
-------
55 . Written Communication from Douglas Maclver, Southwestern Portland Cement Company, Nephi,
UT, to Brent Bradford, Utah Air Conservation Committee, Salt Lake City, UT, July 13. 1984.
56. Performance Guarantee Testing At Southwestern Portland Cement, Pape & Steiner Environmental
Services, Bakersfield, CA, February 1985.
5 7. Compliance Testing At Southwestern Portland Cement, Pape & Steiner Environmental Services,
Bakersfield, CA, April 1985.
5 8 . Emission Tests On Quarry Plant No. 2 Kiln At Southwestern Portland Cement, Pape & Steiner
Environmental Services, Bakersfield, CA, March 1987.
59. Emission Tests On The No. 2 Kiln Baghouse At Southwestern Portland Cement, Pape & Steiner
Environmental Services, Bakersfield, CA, April 1987.
60. Compliance Stack Test Of Cooler No. 3 At Lone Star Florida, Inc., South Florida Environmental
Services, Inc., Belle Glade, FL, July 1980.
61. Stack Emissions Survey Of Lone Star Industries, Inc., Portland Cement Plant At Maryneal Texas,
Ecology Audits, Inc., Dallas, TX, September 1979.
62. Emissions Testing Report Conducted At Kaiser Cement, Coupertino, California, For Kaiser
Cement, Walnut Creek, California, TMA Thermo Analytical, Inc., Richmond, CA, April 30, 1990.
63 . Certification Of Compliance Stack Emission Test Program At Lone Star Industries, Inc. , Cape
Girardeau, Missouri, April &June 1992, Air Pollution Characterization and Control, Ltd., Tolland,
CT, January 1993.
64. Source Emissions Survey Of Essrock Materials, Inc., Eastern Division Cement Group, Kilns
Number 1 And 2 Stack, Frederick, Maryland, Volume I (Draft), Metco Environmental, Addison,
November 1991.
65. M. Branscome, et al, Evaluation Of Waste Combustion In A Dry-process Cement Kiln At Lone
Star Industries, Oglesby, Illinois, Research Triangle Institute, Research Triangle Park, NC,
December 1984.
1 /95 Mineral Products Industry 11.6-23
-------
APPENDIX B
PUBLIC PARTICIPATION PROCEDURES
-------
PUBLIC PARTICIPATION PROCEDURES
for
EPA'S EMISSIONS ESTIMATION GUIDANCE MATERIALS
Introduction and Purpose
The purpose of this report is to document and publicize the public participation procedures which the
U.S. Environmental Protection Agency (EPA) will follow for the submittal, evaluation, and revision or addition of
air pollutant emission factors and other emission estimation techniques. The procedures provide the public with
the opportunity to participate in the establishment of emission factors and techniques both by the submittal of
new material and by the evaluation of that material via a public review process. These procedures are required by
Section 130 of the Clean Air Act of 1990. Revisions or additions submitted and evaluated per these procedures
and subsequently accepted by EPA will be incorporated into EPA's publication "Compilation of Air Pollutant
Emission Factors", Volume I, Stationary Sources, or Volume n, Mobile Sources (AP-42), and its' associated
databases.
Background
EPA has compiled results from various emissions testing programs for over 25 years in AP-42. The
results are most often presented as the mass of emissions expected per unit of process throughput. These
quotients are generally referred to as emission factors, and they are often useful for estimating emissions from
processes similar to those tested. Such estimates are most appropriately used to develop the area-wide emission
inventories used for air quality modeling and control strategy development, hi addition to AP-42, EPA has
distributed a number of guidance documents, memoranda and computer databases containing emission factors,
some of which do not appear in AP-42. Examples of these materials are "Procedures for the Preparation of
Emission Inventories for Carbon Monoxide and Precursors of Ozone" (EPA-450/4-91-016), "Locating and
Estimating Air Emissions from Sources of Styrene" (EPA-454/R-93-011), the Factor Information Retrieval
database system (FIRE), the Volatile Organic Compound (VOC)/Particulate Matter (PM) Speciation Data
System (Speciate), the MOBILES model, and various memoranda on estimating emissions from particular area
source categories issued by the Emissions Inventory Branch.
For several years EPA has solicited comments on draft sections of AP-42 and other emissions estimation
guidance from trade associations, environmental organizations, State and local air pollution agencies, and
individual industry experts. EPA has also worked cooperatively with several trade associations to gather data in
support of emission factor development. Both of these types of interactions are expected to continue in the future
using the procedures described herein. These procedures extend the opportunity to participate in the development
and evaluation of the EPA's emission factor guidance materials to any member of the public.
The Clean Air Act Amendments of 1990 renewed and strengthened national efforts to reduce air
pollution. In particular, Title I of the Amendments addressed the continuing problem of high ambient ozone
levels in many areas of the U.S., resulting in their designation as "ozone non-attainment areas". The Amendments
require comprehensive emission inventories and control strategies to reduce ambient ozone concentrations. Much
of the emission inventory data on which control strategies are developed are based on emission factors.
Therefore, it is critical that these factors be accurate and current. The 1990 Amendments recognized this and
made provisions to ensure that timely and accurate data are used.
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Section 804 of the 1990 Amendments addressed the revision process for emission factors by adding
Section 130 to Part A of Title I of the Act. Section 130 states:
"Within 6 months after enactment of the Clean Air Act Amendments of 1990, and at least every 3 years
thereafter, the Administrator shall review and, if necessary, revise, the methods (emission factors) used
for the purposes of this Act to estimate the quantity of emissions of carbon monoxide, volatile organic
compounds, and oxides of nitrogen from sources of such air pollutants (including area and mobile
sources).
"hi addition, the Administrator shall establish emission factors for sources for which no such methods
have previously been established by the Administrator. The Administrator shall permit any person to
demonstrate improved emissions estimating techniques, and following approval of such techniques, the
Administrator shall authorize the use of such techniques. Any such technique may be approved only after
appropriate public participation. Until the Administrator has completed the revision required by this
section, nothing in this section shall be construed to affect the validity of emission factors established by
the Administrator before the date of the enactment of the Clean Air Act Amendments of 1990."
As seen, the 1990 Amendments reinforced the role of public participation in the emission factor
development process. Anyone in the public is allowed to submit data to establish new emission factors, revise
existing emission factors, or demonstrate improved emissions estimating techniques. (For purposes of this
discussion, EPA is considering emission factors, emissions estimating techniques, and methods of estimating as
interchangeable terms.) The EPA is to evaluate these data and, if found acceptable, approve their use. Any
approvals of new or revised emission factors, whether originating from EPA or the public, can occur only after the
public has had sufficient opportunity to review and comment.
Scope and Limitations
These procedures allow anyone to submit for review emission estimating techniques for any air pollutants
emitted by any stationary point or area source or mobile source, regardless of whether or not the source is
currently addressed by either Volume of AP-42. The procedures can be used to request revisions to existing
factors or to establish emission factors for sources not yet addressed by EPA. Information may be submitted at
any time and may address any aspect of AP-42 or any other EPA emissions estimating materials.
Although Section 130 requires these procedures to be established only for carbon monoxide (CO), oxides
of nitrogen (NOJ, and volatile organic compounds (VOC), EPA intends to follow the same general procedures to
address any criteria, toxic, or other air pollutant, although not necessarily under the same priority.
These procedures are not a means for individual facilities to obtain EPA approval of a site-specific
emission factor or to determine the appropriateness of applying a published EPA factor to a specific facility.
EPA does not approve site-specific factors or judge the appropriateness of its factors for specific facilities. The
responsibility for such decisions continues to be that of the State or local regulating authority, as well as the
facility operators themselves.
EPA's published emission factors are intended to provide an affordable method of estimating emissions
where no better data are available. They are best used to characterize the total emissions loading of a large
geographic area containing many individual facilities. Therefore, these factors attempt to represent a typical or
average facility or process in a given industry. EPA recognizes that other methods of obtaining emissions
estimates may be more accurate than industry-average emission factors, and encourages the use of better methods
whenever the source and/or the State or local regulating authority is able to support those methods. Methods
which may provide more accurate estimates when properly applied include continuous emissions monitors
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(CEMs), source testing, material balances, and engineering calculations. (See Introduction to AP-42 for further
details.)
Procedures for Submittal and Evaluation of Techniques
1. A request for revision or addition of an emissions estimating technique or any other aspect of AP-42 or
other emissions estimation guidance should be submitted in writing to EPA at the following address:
Leader, Emission Factor and Inventories Group
MD-14
USEPA
Research Triangle Park, NC 27711
The section Initial EPA Review for Completeness and Applicability contains a list of the items that must
be addressed by a request in order for it to be considered complete and widely applicable. The section
EPA Review for Technical Acceptability contains the criteria that EPA will use to evaluate whether the
request is technically acceptable. The requestor should be familiar with the material in both of these
sections and should ensure that their request addresses all items.
2. EPA will perform a first-step review of the request for completeness and applicability using the criteria
given in the section Initial EPA Review for Completeness and Applicability. The requestor should be
familiar with the items listed in that section and should ensure that their request addresses all required
items. The emission source for which information is submitted should be non-unique and the emission
estimation technique should be widely applicable to similar sources in order to be considered further by
EPA. EPA will inform the requestor of its evaluation of completeness and applicability within 30 days of
receipt of the request* If the request is deemed complete and applicable, EPA will place a notice to the
public describing the requested revision(s) on the Clearinghouse for Inventories and Emission Factors
(CHIEF) area of the Office of Air Quality Planning and Standards' (OAQPS) Technology Transfer
Network (TTN) bulletin board system. This notice will identify the existing public review group
members to receive EPA's initial recommendation, and it will solicit additional members. (See
Procedures for Participating as a Public Reviewer). If deemed incomplete or not widely applicable by
EPA, the requestor may amend and resubmit the request.
3. After finding the request complete and applicable, EPA will begin an internal review for technical
acceptability. Appendix B describes the criteria that EPA will use to evaluate the proposed revisions for
acceptability. Requestors should be familiar with the criteria in EPA Review for Technical Acceptability
and should evaluate their own request before submittai to ensure that all criteria are adequately
addressed. EPA may have to prioritize requests for technical review if a large number are received at one
time. Priority will be established based upon the guidelines given in the section Factors for Prioritizing
Technical Reviews.
4. EPA will issue its initial recommendation to accept or reject the submitted revisions within 90 days of
beginning the technical review." This initial recommendation will be described in a second notice to the
public on the CHIEF bulletin board. The request (including items 1 through 12 of the section Initial EPA
Review for Completeness and Applicability) and the initial recommendation will be sent to the public
review group, including anyone who has been added to the group during the 90-day technical review
period. (See Procedures for Participating as a Public Reviewer). Detailed test reports (item 13 of the
section Initial EPA Review for Completeness and Applicability) will not ordinarily be sent to the public
review group. They will be sent to individual reviewers upon request, and thus, they must be non-
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confidential.
5. Members of the public review group will submit their individual review comments to EPA within 90 days
of receipt of the review package. Public reviewers should review the material for the same attributes
addressed by EPA (see EPA Review for Technical Acceptability).
6. EPA will consider the review comments and issue a final decision via a third notice on the CHIEF
bulletin board within 30 days.* The final decision notice will summarize the comments and describe any
changes made to the initial recommendation. EPA's acceptance or rejection of any or all public reviewer's
comments are final. Any changes or additions to the estimation guidance are considered "authorized" as
of the date of the final notice. These changes will be reflected in the next possible update to AP-42,
FIRE, guidance documents or memos.
* Deadlines for review may be extended based upon the volume and complexity of the material and other
considerations. All time frames given in terms of Calendar Days, not Business or Working Days.
Procedures for Participating as a Public Reviewer
In addition to the opportunity to submit information on new or revised estimation techniques, the public
may also participate by reviewing EPA's initial recommendations of whether to add or revise techniques through a
public review process. Individuals may request to be on the public review group for one or more sections. Such
requests should be made to EPA in writing at the address given above in item 1 of Procedures for Submitting and
Evaluating Techniques. These requests may also be made via the CHIEF area of the OAQPS TTN bulletin board
system. The request must identify the specific sections of AP-42 that the person is interested in reviewing.
EPA has established a list of contacts for each AP-42 section from previous and ongoing efforts to revise
AP-42. This list is currently used as the starting point for developing a list of interested reviewers for draft
sections. A draft section is typically sent for review to about a dozen individuals representing trade associations,
environmental groups, State and local air agencies, and individual companies. EPA will use this established list
as the initial public review group for complete requests submitted per these procedures. This initial public review
group list will be publicized on the CHIEF area of the TTN bulletin board system as part of the notice that a
request has been deemed complete and applicable. (See item #3 above.) Individuals requesting membership
before the date of the initial recommendation will be sent the public review package and will be added to that
section's public review group list for any future updates.
Reviewers can have their names removed from the list by contacting EPA in writing or via the CHIEF
area of the TTN at the address given above in item 1 of Procedures for Submitting and Evaluating Techniques.
Reviewers may also be removed from the list by EPA if they do not respond to a public review package. A "no
comment" response will be sufficient to show continuing interest in order to keep the reviewer on the review list
for future revisions. EPA invites and encourages any member of the public to participate in the development of
improved emissions estimation techniques according to these procedures.
Initial EPA Review for Completeness and Applicability
EPA encourages the submission of any data (including industry/process descriptions, diagrams, etc.) that
a submitter believes may be useful in the Agency's ongoing effort to review and revise the emission factor
information presented in AP-42. Each submittal will be carefully evaluated according to the criteria and will be
adopted for publication where appropriate.
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In evaluating proposed emission estimation techniques from the public, EPA will conduct a two-step
internal review prior to an external public review. The first step of the internal review is to ensure that all of the
necessary information to conduct an evaluation has been submitted, and that the proposed technique is widely
applicable to similar sources. The second step is the actual evaluation of the technique for technical acceptability.
The result of the second step of the internal EPA review is an "Initial Recommendation" to accept or reject the
proposed revisions. The Initial Recommendation and supporting materials are then reviewed by a public review
group before a final decision is made.
This section describes the minimum information that must be submitted for EPA to perform the first step
of internal review for completeness and applicability. EPA will not begin the second step of internal review for
technical acceptability until the material has passed the first step review. The criteria EPA will use for the second
step technical evaluation are given in the section EPA Review for Technical Acceptability. Listed below are the
items that EPA will review for the first step completeness and applicability review. The submitter should insure
that their proposal adequately addresses all of the following items in order to receive further consideration.
1. Submitter's Name, Mailing Address, and Phone
2. Contact Name, Address, and Phone (if different from Submitter)
3. AP-42 section, guidance document, or database affected
4. Description of emission source affected
(Include SCC codes if available and process flow chart if applicable)
5. Estimated number of facilities affected
6. Estimated total emissions affected
7. Description of proposed change or addition. Identify whether an estimation technique, process
description, both, or other change or addition is being proposed. Also identify which of the
following cases the request addresses:
a. A change to an existing estimation technique or factor without alteration of the source
description, (e.g., "The NOx emission factor for Wall-fired Utility boilers burning
subbituminous coal should be changed from 21 to 17 based on new source tests".)
b. An estimation technique or factor for one or more new source descriptions resulting from a
finer division of an existing source description to distinguish alternative processes, (e.g., "The
NOx emission factor for Wall-fired Utility boilers burning subbituminous coal should be
subdivided to distinguish single-wall fired from double wall-fired boilers, based on an analysis
of existing source tests which shows a significant difference in emission rates between the
two.")
c. An estimation technique or factors for a finer level of resolution of an existing source
description and its technique or factor, (e.g., "The VOC emission factor for a complete fabric
printing operation should be subdivided into individual processes so that emissions from
dryers can be estimated and controlled separately.")
d. An estimation technique for a source not currently addressed by EPA.
8. New or marked-up text of the proposed revision to AP-42, guidance document, or database citation,
which clearly shows where the existing text is affected.
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9. Brief description of the type and source of data or analyses supporting the request. Material
balances and other analyses will be considered. If revision to an existing factor is proposed, the
description should include the data supporting the current factor as well as any new data being
submitted. If submittal is for Case a (see item 7 above), describe why the current factor is
inadequate and why the submitted data should be considered superior to data supporting current
factor. If submittal is for Cases b or c, describe why the more detailed source description is
required, and why emissions are different. In all cases, describe the extent of the data available or
the analyses done to develop the factor or estimation technique.
10. Estimate of the range or uncertainty of the estimation technique. '
11. Describe what effect(s) the proposed change might have on your facility (e.g., it will affect the fee
the company pays, it will affect the regulation applicable to the source, etc.).
12. Any significant issues associated with the request (e.g., no standard test method exists, test method
used is different from that used for the existing factor, definition of pollutant is unclear).
13. All data and analyses necessary to support the request, including test reports, material balance logs,
data evaluations, etc.
14. If test data are submitted:
a. Is the point tested clearly identified?
b. Were process parameters monitored and recorded?
c. Were process parameters within normal ranges?
d. Are upsets and deviations described and explained?
e. Are the test methods and procedures described?
f. Are the methods compatible with approved EPA methods?
g. Is there enough detail for EPA to validate the procedures?
h. Are deviations from the normal procedures identified?
i. Are original raw data and field data sheets included?
j. Are QA/QC procedures described?
EPA Review for Technical Acceptability
The second step of the review begins once all of the information has been received from the submitter. The
submitter is encouraged to review the following information carefully in order to understand the manner in which
submitted information will be evaluated and the criteria used by EPA to determine whether changes to the AP-42
are warranted. The submitter should also be familiar with the guidelines issued by EPA for preparation and
quality rating of emission factors ("Technical Procedures for Developing AP-42 Emission Factors and Preparing
AP-42 Sections", EPA-454/B-93-050, and any subsequent revisions).
It might be useful to first outline the type of test data that is not considered acceptable in making revisions
to AP-42 emission factors. This will help the submitter avoid proposing unacceptable emission estimation
techniques. The following data generally are excluded from consideration:
1. Test data or averages reported in units that cannot be converted to appropriate reporting units.
2. Test series for which the test method is not described or is incompatible with existing EPA
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approved methods.
3. Test series on controlled emissions for which the control device is not specified or is insufficiently
described.
4. Test series in which it is not stated whether the measured emissions were controlled or uncontrolled.
5. Test series in which the process is not clearly identified and described.
6. Test data for which the QA/QC procedures are not clearly defined and documented.
Parties with data to submit should screen the data to ensure that they satisfy these basic requirements.
EPA's guidelines are intended to ensure consistency in the reporting of emission factors for AP-42.
However, the background information and data for each source category will vary with respect to volume and
soundness. For this reason, the Agency exercises a certain degree of flexibility in evaluating the submitted
emissions data. In the case of existing factors based on limited data, a small amount of new data may be
sufficient to prompt a revision to the emission factors. Where extensive data were available to support the factors
initially, more new data would likely be needed to support a change in the factors.
Each source test that passes preliminary EPA approval is assigned a rating. A rating system is needed
because some data might be used when little other information is available, but would be excluded if sufficient
high-quality data were already available. The current version of "Technical Procedures for Developing AP-42
Emission Factors and Preparing AP-42 Sections" should be consulted for the details of the source test rating
criteria.
The emission factors presented in AP-42 generally represent single-value statistical averages determined by
engineering judgement to be representative of the available data for a specific source category operation. These
results are reduced to a single value representing any of various statistical parameters, including arithmetic mean
and median, hi the ideal case, a large number of A-rated source tests representing a cross-section of the industry
would be reduced to a single value which serves as the emission factor. However, if the number of A-rated tests
is so limited that the inclusion of lower-rated tests would improve the robustness of the emission factor, then the
lower-rated test data are included in the compilation of the average value, which would then receive an
appropriately lower emission factor quality rating.
Normally, emission factors are grouped in tables representing source operations or related groups of
operations within a source category. The reliability of these factors is indicated by an overall rating factor ranging
from A (excellent) to E (poor). These ratings take into account the type and amount of data from which the
factors were calculated. As in the case of the source test ratings, the current version of "Technical Procedures for
Developing AP-42 Emission Factors and Preparing AP-42 Sections" should be consulted for the details of the
emission factor rating process.
Factors for Prioritizing Technical Reviews
In the event that EPA does not have adequate resources to evaluate all submitted materials, the following
criteria will be used to determine the priority for material to be reviewed.
1 Estimating techniques for sources for which EPA does not currently have a technique will receive
top priority, unless the estimated magnitude of emissions for the source category is judged
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insignificant by EPA.
2. Estimating techniques for significant sources which currently have D, E, or Unrated emission
factors will receive next priority.
3. Estimating techniques for sources with an existing emission factor which has not been revised to
represent newer process technology or test methods will receive third priority.
4. Sources categories for which the total national impact is greater will receive higher priority than
lesser impact categories. Consideration of national impact will take into account the magnitude of
emissions nationwide, the concentration of emission sources, and the toxicity of the pollutants to be
estimated. A large difference between two requests in total impacts may be sufficient to overcome
the priorities established by items 1,2, and 3, above.
5. Source categories which are being or will shortly be considered by EPA for regulation will receive
lower priority, to avoid duplication of the detailed review to be done as part of the regulatory
process.
Internal Procedures
1. The EFIG Group Leader receives the request, logs it in, and assigns a lead reviewer. The lead reviewer will
usually be the person responsible for the affected chapter or section of AP-42.
COMPLETE BY DAY 5
2. The lead reviewer checks the submitted material for completeness. If the request is complete the lead
reviewer will place the first notice ("Complete request for Section X.XX has been received") on the CHIEF
Bulletin Board and will assemble an internal technical review panel. The first notice should also identify
the members of the existing public review group and solicit additional members. If the request is
incomplete the lead reviewer will inform the submitter of such. The lead reviewer should place the first
notice on the bulletin board OR notify the submitter that the request is incomplete or not applicable OR
notify the submitter that an extension of the first step review time is necessary within 30 days of EPA's
receipt of the request.
COMPLETE BY DAY 35
3. The internal technical review panel should be assembled as soon as possible, since the 90-day clock for
their review begins with the placing of the first notice on CHIEF. The panel should consist of the lead
reviewer and the EFIG Group Leader, as a minimum. A representative of BSD should be added if a MACT
source category may be affected. A representative of IGES should be added if the request concerns an area
source estimation method or otherwise significantly impacts inventory totals. A representative of EMB
should be added if the subrmttal includes any significant stack testing issues. Representatives of AQMD or
any other relevant groups may be added as deemed necessary by the lead reviewer.
The lead reviewer is responsible for making the initial recommendation of whether to accept or reject the
submitted material, after considering input from all technical review panel members. This determination
should be shared with the panel members at least a week before the recommendation is to be placed on the
bulletin board, to allow for resolution of any objections from panel members. The lead reviewer should
place the Initial Recommendation (second notice), whether yea or nay, on the CHIEF Bulletin Board within
8
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90 days of the date of the Completeness determination (first notice).
COMPLETE BY DAY 125
4. The lead reviewer will add anyone to the public review group who has submitted such a request by the date
of the Initial Recommendation, and will mail copies of the review package to the group immediately after
the second notice is placed.
COMPLETE BY DAY 126
5. The lead reviewer should receive comments from the external public review group within 90 days of mailing
the review packages out. This should allow for at least 75 days of review after allowing for transit and
distribution times.
COMPLETE BY DAY 216
6. The lead reviewer should summarize the public review group's comments and place the Final Decision
(third notice) on the bulletin board within 30 days. The lead reviewer will also ensure that AP-42. FIRE, or
other affected materials are appropriately revised. The lead reviewer will also ensure that public group
reviewers who did not respond to the mailing are removed from the public group reviewer list for that AP-
42 section.
COMPLETE BY DAY 246
Note: All time frames given in terms of Calendar Days, not Business or Working Days.
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APPENDIX C
F FACTOR METHOD
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Summary of F-Factor Methods '
f
for Determining Emissions from Combustion Sources
R. T. Shigehara and R. M. Neulicht
Emission Standards and Engineering Division
Office of Air Quality Planning and Standards
U. S. Environmental Protection Agency
Research Triangle Park, N.C.
W. S. Smith and J. W. Peeler
Entropy Environmentalists, Inc.
Research Triangle Park. N. C.
July, 1976
Taken from Source Evaluation Society Newsletter, Vol. 1, No. 4, November 1976
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SUMMARY OF F FACTOR METHODS FOR DETERMINING
EMISSIONS FROM COMBUSTION SOURCES
R. T. Shigehara, R. M. Neulicht, W. S. Smith, and J. W. Peeler
INTRODUCTION
The Federal Standards of Performance for New Stationary Sources, regulating paniculate matter, sulfur
dioxide, and nitrogen oxide emissions from fossil fuel-fired steam generating units, are expressed in terms
of pollutant mass per unit of heat input. Many State regulations for combustion equipment are expressed
in the same form. To arrive at this emission rate, the original method1 required the determination of the
pollutant concentration, effluent volumetric flow rate, and heat input rate. In the October 6, 1975, Federal
Register.2 an "F factor" technique, which required only the determination of the fuel' type, pollutant
concentration and the oxygen (O2) concentration, was promulgated as a procedure to replace the original
method. At the same time, an F Factor approach, based on either O2 or carbon dioxide (€02)
measurements, was promulgated for use in reducing the pollutant concentration data obtained under the
continuous monitoring requirements to the desired units. Recently, wet F Factors,3 which allow the use of
wet basis measurements of the same parameters, and F Factors for wood and refuse have been calculated.
The purpose of this paper is to summarize the various methods and to preset the calculated F Factor
values for the different types of fuels. The various uses of F Factors and errors involved in certain
applications and conditions are also discussed.
SUMMARY OF METHODS
The first method, referred to simply as the F Factor Method, is based on two principles:
1. The ratio of the quantity of dry effluent gas generated by combustion to the gross calorific value of the
fuel is a constant within any given fuel category. This ratio is normally called the dry F Factor;
however, for purposes of-this paper, it will be called the Fa Factor.
2. An excess air correction factor may be expressed in terms of the dry oxygen content of the effluent
stream The use of this method requires dry basis measurements of the pollutant concentration (Cd) and
percent oxygen (%O2d). The emission rate (E) is calculated by the equation:
r r zr 20-9
E = Cd Fd
20.9 -
If the moisture content of the flue gas (B^) is determined, a natural derivative of Equation 1, which would
allow direct wet basis measurements of pollutant and oxygen concentrations, i.e. Cwand %O2w,
respectively, is as follows;
JT r =- I" 20-9
E = Cw
20.9(1 -
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This equation has been approved in principle by the Environmental Protection Agency and may be used if
it is demonstrated that Rw, can be accurately determined and that any absolute error in B*s will not cause an
error of more than ±1.5 percent in the term
20.9
20.9(1-5*.)-
The second technique, called the Fw Factor Method, is based on the same two principles as the Fd Factor
Method, except that the two quantities, the effluent gas and the oxygen concentration, are determined on a
wet basis. The ratio of the quantity of wet effluent gas generated by combustion to the gross calorific value
of the fuel is called the wet F Factor or the Fw Factor. The use of this technique, however, requires in
addition to the wet pollutant concentration (Cw) and oxygen (%C>2w) the determination of the fractional
moisture content of the air (Bm) supplied for combustion. (Guidelines for this determination will be
discussed later. )_The equation for calculating the emission rate is:
20.9
20.9(1 -&«)
This equation is a simplification of the theoretically derived equation.3 Under typical conditions, a positive
bias of no more than 0.25 percent is introduced.
The third procedure, the Fc Factor Method, is based on principles related to but slightly different than
those for the Fd Factor and Fw Factor Methods:
1. For any given fuel category, a constant ratio exists between the volume of carbon dioxide produced by
combustion and the heat content of the fuel. This ratio is called the Fc Factor.
2 The ratio the theoretical carbon dioxide produced during combustion and the measured carbon dioxide
provides an exact basis for dilution correction.
This method requires measurement of the pollutant concentration and percent carbon dioxide (%C02) in the
effluent stream. Measurements may be made on a wet or dry basis. Using the subscripts, "d" and "w", to
denote dry and wet basis measurements, respectively, the equations for calculating E are:
r r J7 ( 10° "1 ^ zr C 10°
E = Cd Fc — = Cw Fc
DETERMINATION OF F FACTORS
Values of Fd in dscf/106 Btu, Fw in wscf/106 Btu, and Fc in scf/106 Btu, may be determined on an
individual case-by-case basis using the ultimate analysis and gross calorific value of the fuel. The
equations are:
„ 10' (3.64%# + 1.53%C + 057%S + 0.14% # - 0.46%0
fd = —
GVC
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106 (5.57%# + 1.53%C + 057%S + 0.14% N - 0.46%0 + 0.21%H 20*)
.
106(0.321%C)
GVC
where = H, C , S, N, 0, and H2O are the concentrations by weight expressed in percent) of hydrogen,
carbon, sulfur, nitrogen, oxygen, and water from the ultimate analysis. ( *Note: .The %H2O term may be
omitted if %H and %O include the unavailable hydrogen and oxygen in the'fbrm of H20.) GCV is the gross
calorific value in Btu/lb of the fuel and must always be the value consistent with or corresponding to the
ultimate analysis.
For determining Fw, the ultimate analysis and GCVwmust be on an "as received" or "as fired" basis, i.e.,
it must include the free water. Often in practice, the ultimate analysis and/or gross calorific value of a
particular fuel are not known. For most commonly used fuels, tabulated average F Factors may be used
instead of the individually determined values. These average values of Fd, Fw, and Fc, calculated from data
obtained from the literature,2 14 are given in Table I. F Factors for wood and bark are also listed in Table
I, and factors for various types of refuse are listed in Table II
ULTIMATE CARBON DIOXIDE
The ratio of Fc to Fd times 100 yields the ultimate percent C02 the maximum C02 concentration that the
dry flue gas is able to attain. By dividing this number into 20.9, a ratio called the F0 Factor is obtained. F0
values calculated from the ultimate analyses of the various fuels are given in Tables I and II.
F0 values can also be calculated from C02 and 02 data obtained in the field by using the following
equation.
20.9 -
%CO
2d
These calculated F0 values can be used to check Orsat data or other analyses of CO2 and O2 that have been
adjusted to a dry basis. The process simply involves comparing F0 values calculated from Equation 8 with
the values listed in Table I or n. Further details of this validation procedure are outlined in Reference 15.
ERRORS AND APPLICATION
The derivations of Equations 1 through 4 are discussed in References 3, 4, and 5. The following
discussion gives further explanation of the F Factors and describes some of the problems and errors that
arise in applying the F Factor Methods. Several uses for F Factors in addition to calculating emission rates
are outlined.
Deviation in F Factors
The F Factors were calculated from data obtained from the literature. In the October 6, 1975, Federal
Register. 2 the values of Fd and Fc were calculated by summing all data points and dividing by the total
number of samples. Then the deviations from the extreme values (highest and lowest) were determined. The
-------
higher of the two values, termed "maximum percent deviation from the average F Factors," are listed in
parenthesis in Table I. These deviations are probably due to differences in the composition of the fuel, and
may also include variations due to the analytical methods and analysts (laboratories). The standard
deviations of the samples were not calculated since much of the data were already averages of several
samples and there may have been more samples from one locale or of one kind than another.
After publication of the Fd and Fc Factors, it was determined that the mid point value would be a better
value than the average for small samples and for data taken from the literature. Therefore, the Fw Factors
and the values for wood and refuse are midpoint values rather than arithmetic averages. The associated
deviations are termed, "maximum percent deviation from the midpoint F Factor."
Fw Factors for refuse, wood, and wood bark were not calculated because of the high variability of free
moisture contents. For example, the moisture in bark may vary from 20 percent (air dried) to 75 percent
(hydraulic debarking).6 Free moisture content variations of ± 15 percent introduce about 5 percent
variations. However, for lignite, the moisture contents vary only from about 33 to 45 percent. This range
causes a deviation of 3.8 percent from the midpoint Fw Factor, which enabled an FwFactor to be
established.
Incomplete Combustion
The assumption of complete combustion is made in the derivation of all F Factor Methods. If products
of incomplete combustion, such as carbon monoxide, are present in the effluent stream, the volume of
effluent gas and carbon dioxide per pound of fuel burned will differ from the values used in calculating the
F Factors. However, adjustments to the measured C02 or O2 concentration can be made, which would
minimize the magnitude of the error when applying Equations 1-5. These adjustments are given by the
following equations:
(%CO2).d,= %CO2 + %CO (9)
( %02 Uj = %O2 - 0.5 %CO (10)
By making these adjustments, the error amounts to minus one-half the concentration of CO present. Thus,
if 1 percent CO (an extreme case) is present, an error of minus 0.5 percent is introduced. Without adjusting
the C02 or O2 concentration, a combustion source having 11 percent C02, 1 percent CO, and 6 percent O2
will result in about plus 9 percent error for the Fc Factor Method and about plus 3 percent for the Fd Factor
and Fw Factor Methods.
Similarly, unbumed combustible matter in the ash will cause the volume of effluent gas and carbon
dioxide per unit of heat input to differ from the calculated F Factor values. This is true, however, only if
the heat input is thought of in terms of the coal input rate times the calorific value. If the heat input rate is
considered as only that calorific value which is derived from the combusted matter, the F Factor Methods
are only slightly affected. In other words, if any portion of the fuel goes through the combustion process
unbumed, the F Factor Methods will not include as heat input the calorific value associated with the
uncombusted matter, and a slight positive bias will be introduced.
The positive bias is due to the combustion process, which is said to consist first of evaporating the free
moisture, then the burning of the volatile matter, and last the burning of the fixed carbon, with the ash
remaining. The volatile matter includes hydrogen, which results in a lower F Factor than the calculated
values. Since a higher proportion of fixed carbon than volatile matter generally remains in the ash, the Fc
Factor Method is affected more than the Fd Factor Fw Factor Methods. For example, assume that 100 Ib of
a coal, which 55.8% C, 5.7% H, 1.1% N, 3.2% S, 21.5% O, and 12.6% ash (percent by weight, as
-------
received basis), is burned and 5 Ib fixed carbon remains in the ash. About plus 2.3 percent error is incurred
with the Fc Factor and less than 1 percent with the Fd Factor and Fw Factor Methods.
Effect of Wet Scrubbers
When wet scrubbers are used, a portion of the carbon dioxide may be absorbed by the scrubbing
solution. Therefore, the Fc Factor Method will yield an emission rate higher than the actual rate. If a gas
stream haying 14% CO2 before the scrubber loses 10 percent of the CO2, or 1.4% CO2, the error is about
plus 13 percent.
The Fd Factor Method is also affected by the loss of CO2 in the scrubber, but to a lesser degree than the
Fc Factor Method. If the gas stream has 6% O2 and 1 4% C02 is lost in the scrubber, the error will be about
plus 2 percent.
The Fw Factor Method is not applicable after wet scrubbers since the scrubber generally adds moisture
to the flue gas, thereby "diluting" the gas stream. The pollutant concentration will be lowered by the same
proportion of moisture added and the O2 concentration will be lower than actual, which would tend to yield
lower than true numbers.
When the scrubbing solution is lime or limestone, the Fc Factor Method may be used after wet
scrubbers. It is generally assumed that due to the optimum operating conditions, the amount of CO:
absorption is minimized and, therefore, the application of the Fc Factor Method will not yield appreciable
errors. However, with limestone scrubbers, there is a possibility of CO2 being added to the gas stream due
to the reaction of S02with the limestone. Therefore, the Fc Factors must be increased by 1 percent.
Determination of Ambient Air Moisture
Guidelines have been developed for the determination of BW,, the moisture fraction in ambient air, in
Equation 3, which will soon be published in the Federal Register. The guidelines are presented below.
Approval may be given for determination of BW, by on-site instrumental measurement provided that the
absolute accuracy of the measurement technique can be demonstrated to be within + 0.7 percent water
vapor. In lieu of actual measurement, BW, may be estimated as follows: (Note that the following estimating
factors are selected to assure that any negative error introduced in the emissions by the estimating term
20.9
will not be larger than -1.5 percent. However, positive errors, or over-estimation of emissions, of as much
as 5 percent may be introduced depending upon the geographic location of the facility and the associated
range of ambient moisture.)
1. Bwa = 0.027. This factor may be used as a constant value at any location.
2. BW» = highest monthly average of Bw, that occurred within a calendar year at the nearest Weather
Service Station, calculated using data for the past 3 years. This factor may be used on an annual basis
at any facility.
3. BW, = highest daily average of Bw that occurred within a calendar month at the nearest Weather
Service Station, calculated for each month for the past 3 years used as an estimating factor for the
respective calendar month.
-------
Sampling Location and Sampling Points
Ambient air leakage into an exhaust system may cause variations across the duct or stack in the relative
concentrations of C02 and Oz For this reason, the Federal regulations' specify that C02 or O2 be measured
simultaneously and approximately at the same point as the gaseous pollutants measurements.
For paniculate emission performance tests, which require traversing, it is specified that the O2 samples
be obtained simultaneously by traversing the duct at the same sampling location used for each run of the
Method 5. This requirement may be satisfied by attaching a stainless steel tube to the paniculate sampling
probe and, using a small diaphragm pump, obtaining an integrated gas sample over the duration of the run
(of Reference 1). The sample should be analyzed using an Orsat apparatus.
As an alternative to traversing the same sampling points of Method 5, a minimum of 12 oxygen
sampling points may be used for each run. This would require a separate integrated gas sampling train
traversing the duct work simultaneously with the paniculate run.
Other Applications
In addition to calculating emission rates, F Factors have several other uses. If Qjd , the dry effluent
volumetric flow rate, or (}„,, the wet effluent volumetric flow rate, and QH, the heat input rate, are
measured, a value of Fa, Fw, or Fcmay be calculated. These equations are given below:
„ Q* 20.9 -%02
Fi (cole) = •=— - (11)
QH 20.9
Q« 20.9(l-B»a)-%02
Fd (cole) = =— - (12)
QH 20.9
re (caic) = - - = - - (13)
QH 100 QH 100
The calculated values may then be compared to tabulated values of the F Factors to facilitate a material
balance check.
If desired, QH can be calculated by using the Equations 11 through 13. In the past, it has been observed
that the measurement of Q, has been significantly greater than the stoichiometric calculations rates. The
discrepancy is usually due to errors in determining Q,. Due to aerodynamic interferences and improper
alignment of the pilot tubes, higher than real readings have been obtained. Therefore, errors in measuring
QS are positive, which leads to higher than true firing rates.
If an ultimate analysis and calorific determination of a particular fuel are made and the F Factor value is
calculated, the accuracy of the results may be checked by comparison with the tabulated F Factors.
SUMMARY
The various F Factor Methods have been summarized and calculated F Factors for fossil fuels, wood,
wood bark, and refuse material have been presented. In addition, some of the problems and errors that arise
in applying the F Factor Method for calculating power plant emission rates were discussed and other uses
of the F Factors were outlined.
-------
REFERENCES
1. Standards of Performance for New Stationary Sources. Federal Register. 36:247. Part II. December
23, 1971.
2. Requirements for Submittal of Implementation Plans and Standards for New Stationary Sources.
Federal Register.40:194. Part V. October 6,1975.
3. Shigehara, R. T. and R. M. Neulicht. Derivation of Equations for Calculating Power Plant Emission
Rates, O2 Based Method - Wet and Dry Measurements. Emission Measurement Branch, ESED,
OAQPS, and U. S. Environmental Protection Agency, Research Triangle Park, N.C. July 1976.
4. Shigehara, R. T., R. M. Neulicht, and W. S. Smith. A Method for Calculating Power Plant Emissions.
Stack Sampling News. 1 (l):5-9. July 1973.
5. Neulicht, R. M. Emission Correction Factor for Fossil Fuel-Fired Steam Generators: C02 Concentration
Approach. Stack Sampling News. 2 (8);6-ll. February 1975.
6. Fuels, Distribution, and Air Supply. In: C-E Bark Burning Boilers (Sales Brochure). Windsor, Conn.,
Combustion Engineering Inc. p.5.
7. Kaiser, E. R. Chemical Analyses of Refuse Components. In: Proceedings of 1966 National Incinerator
Conference. The American Society of Mechanical Engineers, 1965. p.84-88.
8. Kaiser, E. R., C. D. Zeit, and J. B. McCaffery. Municipal Refuse and Residue. In: Proceedings of 1968
National Incinerator Conference. The American Society of Mechanical Engineers, 1968. p.142-152.
9. Kaiser, E. R. and A. A. CarrQtti. Municipal Refuse with 2% and 4% Addition of Four Plastics:
Polyethylene, Polyurethane, Polystyrene, and Polyvinyl Chloride. In: Proceedings of 1972 National
Incinerator Conference. The American Society of Mechanical Engineers. 1972. P.230-244.
10. Kaiser, E. R. The Incineration of Bulky Refuse. In: Proceedings of 1966 National Incinerator
Conference. The American Society of Mechanical Engineers, 1966. p.39-48.
11. Newman. L. L. and W. H. Ode. Peat, Wood, and Miscellaneous Solid Fuels. In: Mark's Standard
Handbook for Mechanical Engineers, Baumeister, T. (ed.). 7th ed. New York, McGraw-Hill Book
Company, 1967. Chapter 7, p.19.
12. MacNight, R. J. and J. E. Williamson. Incineration: General Refuse Incinerators. In: Air Pollution
Engineering Manual, Danielson, J. A. (ed.). 2nd ed. OAWM, OAQPS, U. S. Environmental
Protection Agency, Research Triangle Park, N.C. AP-40. May 1973. p.446.
13. Steam, Its Generation and Use. 37th ed. New York, the Babcock and Wilcox Company, 1963.
Appendix 3-A4.
14. The Ralph M. Parsons Company. Solid Waste Disposal System, Chicago. Vol. II Study Report
Appendixes. Prepared for Bureau of Engineering, Department of Public Works, City of Chicago.
May 1973.
-------
15. Shigehara, R. T., R. M. Neulicht, and W. S. Smith. Validating Orsat Analysis Data from Fossil-Fuel-
Fired Units. Emission Measurement Branch, ESED, OAQPS, U. S. Environmental Protection
Agency, Research Triangle Park, N.C. June 1975.
-------
TABLE I. F FACTORS FOR VARIOUS FUELS
Fc
sc£7106Btu F0
1980(4.1) 1.070(2.9)
1810(5.9) 1.140(4.5)
1920(4.6) 1.0761(2.8)
1430(5.1) 1.3461(4.1)
1040(3.9) 1.79(2.9)
1200(1.0) 1.10(1.2)
1260(1.0) 1.479(0.9)
1840(5.0) 1.5(3.4)
1860(3.6) 1.056(3.9)
a Numbers in parenthesis are maximum deviations (%) from either the midpoint or average F Factors.
Note: To convert to metric system, multiply the above values by 1.123 x 10"4 to obtain scm/106 cal.
c All numbers below the asterisk (*) in each column are midpoint values. All others are averages.
Fuel Type
Coal
Anthracite
Bituminous
Lignite
Oil
Gas
Natural
Propane
Butane
Wood
WnnH Wnrl-
Fd
dscfflO6 Btu
10140 (2.0)
9820 (3.1)
9900 (2.2)
9220 (3.0)
8740 (2.2)
8740 (2.2)
8740 (2.2)
9280(1.9)
OA40 (d. \\
FW*C
wsctflO6 Btu
10580 (1.5)
10680(2.7)
12000 (3.8)
10360 (3.5)
10650 (0.8)
10240 (0.4)
10430 (0.7)
-------
TABLE D. MIDPOINT F FACTORS FOR REFUSE2'14*"
Fd Fc
dscF/106Btu wscF/lO^tu F0
9260 (3.6)
9590 (5.0)
9173
9860
10010
9120
9640 (4.0)
1870 (3.3)
1840 (3.0)
1380
1700
1810
1480
1790 (7.9)
1 046 (4.6)
1.088(2.4)
1.394
1.213
1.157
1.286
1.110(5.6)
Paper and Wood Wastes0
Lawn and Garden Wastes'1
Plastics
Polyethylene
Polystyrene
Polyurethane
Polyvinyl chloride
Garbage
Miscellaneous
Citrus rinds and seeds
Meet scraps, cooked
Fried fats
Leather shoe
Heel and sole
composition
Vacuum cleaner catch
Textiles
Waxed milk cartons
* Numbers in parentheses are maximum deviations (%) from the midpoint F Factors.
b To convert to metric system, multiply the above values by 1.123 x 10"4 to obtain scm/106cal.
c Includes newspapers, brown paper, corrugated boxes, magazines, junk mail, wood, green logs, rotten
timber.
d Includes evergreen shrub cuttings, flowing garden plants, leaves, grass.
'Includes vegetable food wastes, garbage (not described).
9370
9210
8939
9530
9480
9490
9354
9413
1920
1540
1430
1720
1550
1700
1840
1620
1.020
1.252
1.310
1.156
1.279
1.170
1.060
1.040
-------
APPENDIX D
HAZARDOUS AIR POLLUTANTS
-------
SECTION 112(b) LIST OF 189 HAZARDOUS AIR POLLUTANTS
CAS# POLLUTANT NAME
75070 Acetaldehyde
60355 Acetamide
75058 Acetonitrile
98862 Acetophenone
53963 2-Acetylaminpfluorene
107028 Acrolein
79061 Acrylamide
79107 Acrylic Acid
107131 Acrylonitrile
107051 Allyl Chloride
92671 4-Aminobiphenyl
62533 Aniline
90040 o-Anisidine
1332214 Asbestos
71432 Benzene
92875 Benzidine
98077 Benzotrichloride
100447 Benzyl chloride
92524 Biphenyl
117817 Bis(2-ethylhexyl)phthalate
(DEHO)
542881 Bis(chloromethy)ether
75252 Bromoform
106990 1,3-Butadiene
156627 Calcium cyanamide
105602 Caprolactam
133062 Captan
63252 Carbaryl
75150 Carbon disulfide
56235 Carbon tetrachloride
463581 Carbonyl sulfide
120809 Catecol
133904 Chloramben
57749 Chlordane
7782505 Chlorine
79118 Chloroacetic acid
532274 2-Chloroacetophenone
108907 Chlorobenzene
510156 Chlorobenzilate
67663 Chloroform
107302 Chloromethyl methyl ether
126998 Chloroprene
1319773 Cresols/Cresylic acid (isomers
and Mixture
95487 o-Cresol
108394 m-Cresol
37 HIGH
PRIORIT
Y
HI
ffl
ffl
HI
HI
HI
HI
PM OR VOC OR
CONDEN NOT
REAC.
VOC
VOC
VOC
VOC
PM or C VOC
VOC
VOC
VOC
VOC
VOC
PM or C VOC
VOC
VOC
PM Not ORG
VOC
PM or C VOC
VOC
VOC
VOC
PM or C VOC
VOC
VOC
VOC
OZONE
DEPL.
PM
PMorC
PMorC
PMorC
PMorC
PMorC
HI
VOC
VOC
VOC
VOC
NOT ORG
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
O3
-------
106445 p-Cresol VOC
98828 Cumene VOC
94757 2,4-D, salts and esters PM or C
72559 DDE PM or C
334883 Diazomethane VOC
132649 Dibenzofiirans PMorC VOC
96128 12-Dibromo-3-chloropropane VOC
84742 Dibutylphthalate PMorC VOC
106467 " l,4-Dichlorobenzene(p) VOC
91941 3,3-Dichlorobenzidine PMorC VOC
111444 Dichloroethyl ether (Bis ffl VOC
(2-chloroethyl)ether)
542756 1,3 Dichloropropene VOC
62737 Dichlorvos VOC
111422 Diethanolamine VOC
121697 N,N-Diethyl aniline VOC
(n,N-Dimethylaniline)
64675 Diethylsulfete VOC
119904 3,3-Dimethyl benzidine PMorC VOC
60117 Dimethyl aminoazobenzene PMorC VOC
119937 3,3'Dimethyl benzidine PMorC VOC
79447 Dimethyl carbamoyl chloride VOC
68122 Dimethyl formamide VOC
57147 1,1-Dimethylhydrazine VOC
131113 Dimethyl phthalate VOC
77781 Dimethyl sulfate VOC
534521 4,6-Dinitro-o-cresol, and salts PMorC VOC
51285 2,4-Dinitrophenol PMorC VOC
121142 2,4-Dinitrotoluene VOC
123911 l,4-Dioxane(l,4 VOC
Diethyleneoxide)
122667 1.2-Diphenylhydrazine VOC
106898 Epichlorohydrin VOC
(1 -Chloro-2,3-epoxypropane)
106887 1.2-Epoxybutane VOC
140885 Ethyl acrylate VOC
100414 Ethyl benzene VOC
51796 Ethyl carbamate (Urethane) VOC
75003 Ethyl Chloride (Chlrorethan) VOC
106934 Ethylene Dibromide HI VOC
(Dibromoethane)
107062 Ethylene dichloride (1,2- HI VOC
Dichloroethane)
107211 Ethlene glycol VOC
1515 64 Ethylene imine (Aziridine) VOC
75218 Ethylene oxide HI VOC
96457 Ethylene thiourea VOC
75343 Ethylidene dichloride VOC
(1,1 -Dichloroethane)
50000 Formaldehyde HI VOC
76448 Heptachlor VOC
-------
118741 Hexachlorobenzene
87683 Hexachlorobutadiene
77474 Hexachlorocyclopentadiene
67721 Hexachloroethane
822060 Hexamethylene-1,6-
diisocyanate
680319 Hexamethylphosphoramide
110543 Hexane
302012 Hydrazine
7647010 Hydrochloric acid (hydrogen
chloride gas only)
7664393 Hyrdogen fluoride
(Hydrofluoric acid)
123319 Hydroquinone
78591 Isophorone
58899 Lindane
10831 Maleic anhydride
67561 Methanol
72435 Methoxychlor
74839 Methyl bromide
(Bromomethane)
74873 Methyl chloride
(Chloromethane)
71556 Methyl chloroform
(1,1,1 -Trichloroethane)
78933 Methyl ethyl ketone
(2-Butanone)
60344 Methyl hydrazine
74884 Methyl iodid (lodomethane)
108101 Methyl isobutyl ketone
(Hexone)
624839 Methyl isocyanate
80626 Methyl methacrylate
1634044 Methyl tert butyl ether
101144 4,4'-Methylenebis
(2-chloroaniline)
75092 Methylene Chloride
(Dichloromethane)
101688 Methylene diphenyl
diisocyanate(MDI)
101779 4,4-Methylenedianiline
91203 Naphthalene
98953 Nitrosobenzene
92933 4-Nitrobiphenyl
100027 4-Nitrophenol
79469 2-Nitropropane
684935 N-Nitroso-N-methylurea
62759 N-Nitrosodimethylamine
59892 N-Nitrosomorpholine
56382 Parathion
HI
VOC
VOC
VOC
VOC
VOC
VOC
VOC
Not ORG
Not ORG
PMorC
PMorC
PMorC
PMorC
PMorC
ffl
ffl
PMorC
PMorC
PMorC
VOC
VOC
VOC
VOC
VOC
NR
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
NR
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
O3
PMorC
-------
82688 Pentachloronitrobenzene
87865 Pentachlorophenol
108952 Phenol
106503 p-Phenylenediamine
75445 Phosgene HI
7803512 Phosphine
7723140 Phosphorus
85449 Phthalic anhydride
1336363 Polchlorinated biphenyls
(Aroclors)
1120714 1,3-Propane sultone
57578 beta-Propiolactone
123386 Propionaldehyde
114261 Propoxur (Baygon)
78875 Propylene dichloride
(1,2-Dichloropropane)
75569 Propylene oxide
75558 1,2-Propylenimine
(2-Methyl aziridine)
91225 Quinoline
106514 Quinone
100425 Styrene ffl
96093' Styrene oxide
1746016 2,3,7,8-Tetrochlorodebenzo- ffl
p-dioxin
79345 1,1,2,2-Tetrachloroethane
127184 Tetrachloroethylene ffl
(Perchloroethylene)
7550450 Titanium tetrachloride
108883 Toluene ffl
95807 2,4-Toluene diamine
584849 2,4-Toluene diisocyanate ffl
95534 o-Toluidine
8001352 Toxaphene
(Chlorinated camphene)
120821 1,2,4-Trichlorobenzene
79005 1,1,2-Trichloroethane
79016 Trichloroethylene ffl
95954 2,4,5-Trichlorophenol
88062 2,4,6-Trichlorphenol
121448 Triethylamine
1582098 Trifluralin
540841 2,2,4-Trimethylpentane
108054' Vinyl acetate
593602 Vinyl bromide
75014 Vinyl chloride ffl
75354 Vinylidene chloride
(Dichloroethylene)
1330207 Xylenes(isomers & Mixtures) ffl
95476 o-Xylenes ffl
108383 m-Nylenes ffl
PMorC
PMorC
PMorC
PMorC
VOC
VOC
VOC
VOC
Not ORG
VOC
VOC
PMorC
PMorC
PMorC
PMorC
PMorC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
VOC
-------
106423 p-Xylenes ffl VOC
Antimony Compounds HI PMorC NotORG
Arsenic Compounds HI PMorC NotORG
(inorganic including arsine)
Beryllium Compounds HI PMorC NotORG
Cadium Compounds HI PMorC NotORG
Cobalt Compounds PM or C
Coke Oven Emissions ffl PM or C VOC
Cyanide Compounds 1 PM or C Not ORG
Clycol Ethers2 ffl VOC
Lead Compounds ffl PMorC NOTORG
Manganese Compounds ffl PMorC NOTORG
Mercury Compounds ffl PMorC NOTORG
Fine Mineral FibersS PM NOTORG
Nickel Compounds ffl PMorC NOTORG
Polycyclic Organic Matter 4 ffl PMorC VOC
Radionuclides PM or C NOT ORG
(including radon)5
Selenium Compounds PM or C NOT ORG
NOTE: For all listings above which contain the word "compounds" and for glycol ethers, the following
applies: Unless otherwise specified, these listings are defined as including any unique chemical substance
that contains the named chemical (i.e. antimony, arsenic, etc.) as part of that chemical's infrastructure.
1 X'CN where X = H1 or any other group where a formal dissociation may occur. For example KCN or
Ca(CN)2
2 includes mono- and di- ethers of ethylene glycol, diethylene glycol, and triethylene glycol R-
(OCH2CH2)n-OR' where n = 1 , 2, or 3 R = alkyl or aryl groups R1 = R, H, or groups which, when
removed, yield glycol ethers with structure:; R-(OCH2CH)n-OH polymers are excluded from the glycol
category.
3 includes mineral fiber emissions from facilities manufacturing or processing glass, rock, or slag fibers
(or other mineral derived fibers) of average diameter 1 micrometer or less.
4 includes organic compounds with more than one benzene ring, and which have a boiling point greater
than or equal to lOOoC
5 a type of atom which spontaneously undergoes radioactive decay.
-------
APPENDIX E
ACRONYMS
-------
ACRONYMS
ACT Alternative Control Techniques
AMS Area and Mobile Source
AP-42 Compilation of Air Pollutant Emission Factors, Volume I: Stationary Point and
Area Sources
APPCD Air Pollution Prevention and Control Division
BBS Bulletin Board System
BDL Below Method Detection Limit
BIDS Background Information Documents
BTU British Thermal Unit
CAA Clean Air Act of 1990
CEMS Continuous Emission Monitoring System
CHIEF Clearinghouse for Inventories and Emission Factors
CO Carbon Monoxide
CTC Control Technology Center
CTG Control Techniques Guidelines
EFIG Emission Factors and Inventory Group
EMTIC Emission Measurement Technical Information Center
ESD Emission Standard Division
FIRE Factor Information Retrieval System
HAPs Hazardous Air Pollutants
L&E Locating and Estimating Air Toxic Emissions from Source Category of
Substance
MACT Maximum Achievable Control Technology
MDL Method Detection Limits
NATICH National Air Toxics Information Clearinghouse
NESHAP National Emisison Standard for Hazardous Air Pollutant
NOX Nitrogen Oxide
NSPS New Source Performance Standard
NTTS National Technical Information Service
OAQPS Office of Air Quality Planning and Standards
OSHA Occupational Safety and Health Administration
PB Lead
PM Paniculate Matter
PM Paniculate Matter
RREL Risk Reduction Engineering Laboratory
SCC Source Classification Codes
SO2 Sulfur Dioxide
SOP Standard Operating Procedure
STIRS Source Test Information Retrieval System
TOC Total Organic Compounds
TRI Toxic Release Inventory
TSAR Test Method Storage and Retrieval
VOC Volatile Organic Compounds :
-------
* TECHNICAL REPORT DATA
(PLEASE READ INSTRUCTIONS ON THE REVERSE BEFORE COMPLETING)
1. REPORT NO.
EPA-454/R-94-022
3. RECIPIENTS ACCESSION NO.
4. TITLE AND SUBTITLE
PUBLIC PARTICIPATION PROCEDURES FOR EPA'S EMISSION
ESTIMATION GUIDANCE MATERIALS
6. REPORT DATE
5/15/97
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
RONALD B. RYAN
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF AIR QUALITY PLANNING AND STANDARDS
RESEARCH TRIANGLE PARK, NC 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
NA
12. SPONSORING AGENCY NAME AND ADDRESS
DIRECTOR, OFFICE OF AIR QUALITY PLANNING AND STANDARDS
OFFICE OF AIR AND RADIATION
U.S. ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
THIS DOCUMENT DETAILS THE PROCEDURES THAT EPA WILL FOLLOW TO ALLOW AND ENCOURAGE
MEMBERS OF THE PUBLIC TO SUBMIT PROPOSED AIR EMISSIONS ESTIMATION METHODS OR TO ASSIST IN
THE REVIEW OF SUCH SUBMITTALS, AS REQUIRED BY SECTION 130 OF THE CLEAN AIR ACT.
17.
KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
EMISSIONS FACTORS
EMISSIONS ESTIMATION METHODS
PUBLIC PARTICIPATION
b. IDENTIFIERS/OPEN ENDED TERMS
AIR POLLUTION CONTROL
C. COSATI FIELD/GROUP
18. DISTRIBUTION STATEMENT
RELEASE UNLIMITED
UNCLASSIFIED
21. NO. OF PAGES
140
22. PRICE
UNCLASSIFIED
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