EPA-454/R-94-022
PUBLIC PARTICIPATION PROCEDURES
FOR EPA's EMISSION ESTIMATION
GUIDANCE MATERIALS
Office of Air Quality Planning and Standards
Office of Air and Radiation
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
May 1997
-------
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-94-022
-------
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 II, 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. In 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)TParticulate 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.
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).
"In 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 (NOX), 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 (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 submittal 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-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.
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.
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.
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
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. In 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
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 ESD 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 submittal 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 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.
------- |