May 31, 2023
2023 NEI Plan: Draft, May 2023
1 Introduction
This document lays out the EPA's plan for developing the 2023 National Emissions Inventory (NEI), and its
intended audience is state, local, and tribal (S/L/T) emissions inventory developers. For more information on the
NEI, please refer to the 2020 NEI TSD. The Air Emissions Reporting Rule (AERR) (40 CFR Part 51, Subpart A)
provides the specific requirements for state, local, and tribal (S/L/T) agencies to follow in reporting their
emissions. The rule requires submission of point sources, nonpoint sources, and mobile model inputs (with one
exception). This plan provides additional details regarding EPA's preferences and principles for how S/L/T
agencies should comply with the AERR. In deciding how to submit their emissions, it is important that S/L/T
agencies follow the principles of this plan to ensure that S/L/T-submitted emissions can be used in the NEI and
to avoid missing emissions or double-counted emissions.
For experienced inventory developers, Section 1.1 provides key process changes with links to the sections where
these changes are discussed in more detail. If you are an experienced developer, you may not need to review
this entire document. We discuss the schedule, best practices for S/L/T inventory developers, the Emissions
Inventory System (EIS), what feedback EPA will provide, and how EPA will develop the final NEI with the
selection process.
1.1 General Plan: Stat Changes
With potential budget constraints, we plan to replicate many of the successful 2020 processes for the 2023
inventory development process. Things that were successful and will be repeated for the 2023 process include:
One version of the full NEI (no releases of multiple versions)
Releases of data categories as they are completed
All fires being stored and released in the Nonpoint data category
Requiring throughput for computing nonpoint industrial and commercial/institutional fuel combustion
sources (ICI) where direct nonpoint ICI emissions are not submitted
Using S/L/T-submitted point inventory data to generate "default" emissions (fuel consumption for ICI)
input templates for computing nonpoint Solvent Utilization, Publicly-Owned Treatment works (POTWs),
Stage 1 Gasoline Distribution, and ICI estimates
Extended deadlines for submitting much of the nonpoint data category sectors.
The improved nonpoint survey from 2020
The Wagon Wheel (WW) tool with Input Template submittals used for generating much of the nonpoint
data category sources
Using the NEI, NOMAD (Nonpoint Method Advisory Committee), and Fires SharePoint sites to share
important information and resources. Email Lindsay Dayton to be added as a member to any of these
sites. Sending NEI and EIS status update newsletters every 3-5 weeks for those subscribed to the NEI
SharePoint site.
Where possible, the NEI development process has been streamlined over the last couple of cycles to reduce
S/L/T submittal burden. For the 2023 NEI, we are taking additional steps to help reduce some of the
inventory development burden on S/L/Ts, particularly for nonpoint sources. In addition, we are highlighting
a few key changes that are discussed in greater detail in this document (click the highlighted section to move
directly to that area of the document):
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Wagon Wheel Input Templates absorbed into the EIS (Section 7.4)
Overhaul of source classification codes (SCCs) for Residential Wood Combustion (RWC), including ability
for S/L/Ts to submit wood consumption in lieu of providing burn rates or appliance fractions; also
updated emission factors (Section 4.1.2)
More flexible nonpoint submittal schedule to allow S/L/T review of final activity data (Section 7.6)
Reflection of iterative QA and Completeness Reports, implemented during the 2020 NEI cycle (Section 5)
Introduction of EPA estimates and nonpoint survey entries for a few new sources, likely to include
exempt (RWC) stoves, residential cooking, food trucks, asphalt roofing, structure fires, and motor
vehicle fires (Section 7.2)
Inclusion of dioxins and furans into NEI selection (Section 4.1.3)
The public release of the full 2023 NEI is expected to be March 31, 2026.
1.2 Suggested Roles and Responsibilities for EPA Region ces
As part of the NEI process, we would like to help guide how regional offices can assist with the requirements for
completing the NEI on schedule. As a part of that process, we would like for the regions to assist us with the
following items:
Promoting requests for sending in activity data for all non-wagon wheel sectors where we have
identified
Making sure S/L/Ts provide inputs for the wagon wheel according to the schedule in the NEI plan
o Specifically, ensuring S/L/Ts submit either direct emissions or input template data for nonpoint
ICI fuel combustion
Helping to make sure S/L/Ts complete and submit the nonpoint survey on time
Helping us ensure that S/L/Ts review draft estimates and information and getting comments back by the
timelines laid out
Prompt review of new EPA emission-estimate methods or major updates to existing methods
We will make sure to keep the regions informed of any delays in the schedule as laid out in the NEI plan. As
deadlines approach, it would be expected that regions would reach out to their member S/L/Ts and inform them
of imminent deadlines.
2 Schedule
The public release of the complete 2023 NEI is expected to be March 31, 2026.
Significant changes to the overall 2023 NEI schedule (compared to the 2020 NEI Plan) are limited to the
nonpoint data category where emissions and input template submittals will be due at varying times based on
source category and availability of final activity data. Otherwise, the submittal deadlines for point, onroad
mobile, and nonroad mobile are January 15, 2025, an "holiday" extension of the December 31, 2024 submittal
deadline in the existing AERR. The March 31, 2025 deadline exists for the nonpoint survey to allow S/L/Ts to
review all draft EPA estimates, and their 2023 point submittals (for nonpoint sources that utilize point
reconciliation) to determine if they intend to allow EPA estimates to supplement their nonpoint emissions
submittals. The March 31, 2025 deadline is also the final date for submitting emissions and/or input activity data
(wagon wheel input templates) for nonpoint sources where final activity data or EPA estimates have been
provided.
Fires (prescribed and wildfires), moved to the nonpoint data category for the 2020 NEI, will again be developed
in a separate, though similar, process and are therefore split out into its own subsections in this document.
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We have developed a more refined set of S/L/T submittal dates for the 2023 NEI nonpoint data category to align
with the availability of 2023 activity data and EPA draft estimates. In general, we are extending S/L/T submittal
deadlines for several wagon wheel sources: 30 additional days for wagon wheel input templates, and 60 days for
emissions and documentation after final activity data are loaded into the wagon wheel. The new nonpoint
submittal schedule is therefore refined as such:
January 15, 2025
o Commercial Marine Vessels
o Rail (lines and yard) estimates
March 31, 2025
o Entire Nonpoint Survey
o Emissions for all source not estimated by EPA tools
o Emissions for all stationary sources that are not in the Wagon Wheel (e.g., oil and gas,
agricultural fertilizer application, portable fuel containers)
o All emissions or input templates for source categories not final in Wagon Wheel Version 2
(released on January 31, 2025)
August 31, 2025
o Input Templates for sources where activity data updated in Version 3 of the Wagon Wheel
(released on July 31, 2025). This will likely include at least the following sources: solvents, RWC,
ICI, POTWs, road dust, asphalt paving, residential grilling, residential heating, nonpoint gasoline
distribution, open burning, construction dust, composting, and non-combustion mercury.
September 30, 2025
o Emissions and documentation for sources where activity data updated in Version 3 of the
Wagon Wheel (released on July 31, 2025). This will likely include at least the following sources:
solvents, RWC, ICI, POTWs, road dust, asphalt paving, residential grilling, residential heating,
nonpoint gasoline distribution, open burning, construction dust, composting, and non-
combustion mercury.
Table 2-1: 2023 Overall NEI Schedule
Item: Overall
Who
Details
Deadline
EPA finalizes implementation of
changes to codes and QA routines
for 2023
EPA
Code changes and QA routines to be reflected in
EIS (and web services)
11/15/2023
EPA posts expected pollutants list
to 2023 NEI website
EPA
Point and Nonpoint (including fires). Mobile
source expected pollutants are defined by the
MOVES model.
11/15/2023
Submission Window Opens for
S/L/T submittals
S/L/T
All data categories. Point window will open by
3/1/2024 to accommodate CAERS submitters.
7/1/2024
EPA sends reminder to S/L/Ts to
review EIS Completeness Reports
for all data categories to S/L/Ts and
Regional Offices
EPA
EPA will send final Completeness Report to Air
Directors approximately 1 month after deadline
and grace period ends (February 2025 for all data
categories, except April 2025 for nonpoint)
12/1/2024
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Item: Overall
Who
Details
Deadline
S/L/Ts last day for EIS submittal of
Point, Onroad Mobile and Nonroad
Mobile data category emissions,
and all fires data
S/L/T
The regulatory deadline for emissions data and
model inputs is December 31, 2024. However,
the EPA provides a grace period because of the
holidays at the end of the season. Any submittals
after this date will not be evaluated for
Completeness Report feedback and are not
guaranteed to be accepted into the 2023 NEI.
1/15/2025
S/L/Ts last day to submit emissions
and documentation describing
emissions calculations for nonpoint
source categories without EPA
Tools
S/L/T
For source categories for which EPA does not
estimate on its own. Check the expected
pollutants list to know which sources have EPA
tools.
1/15/2025
EPA sends final completeness
reports to S/L/Ts, Regional Offices
and Air Directors
EPA
For all data categories except nonpoint
2/15/2025
S/L/Ts last day for completing their
nonpoint survey
S/L/T
For nonpoint data category
3/31/2025
S/L/Ts last day to submit input
templates for EPA tools
S/L/T
Input templates for fires and Wagon Wheel
categories should be submitted in EIS. For oil and
gas, these should be submitted to ERG.
30 days after
each WW
release after
1/15/2025
S/L/Ts last day to submit emissions
and documentation describing
calculations for nonpoint sources
with EPA Tools
S/L/T
For sources which EPA does estimate, EPA prefers
input template submissions so that a cohesive
dataset for the nation is created. However, you
do have the option of submitting emissions, as in
previous years. Note that new for this inventory
cycle is a requirement to provide documentation
on how you created the estimated emissions for
these sources.
60 days after
each WW
release after
1/15/2025
EPA sends final completeness
reports to S/L/Ts, Regional Offices
and Air Directors
EPA
For nonpoint data category
4/30/2025
2023 Full Public Release
EPA
Includes functioning NEI Data page with query
tools, summaries, and Technical Support
Documentation
3/31/2026
The nonpoint survey is due March 31, 2025. For stationary nonpoint sources which have EPA tools, inputs and
input templates are due whichever is later: March 31, 2025, or, 30 days after the EPA estimates are released;
alternatively, emissions and the documentation for how you calculated those emissions are due whichever is
later: March 31, 2025, or, 60 days after the estimates are released. EPA strongly recommends that S/L/Ts start
on their nonpoint submissions at least several months in advance of these deadlines. We have developed a
draft of when data inputs for nonpoint are going to be available and are basing our suggested milestones on that
availability (see Section 7.3). For those nonpoint sources that do not rely on the Wagon Wheel for S/L/T
feedback (e.g., commercial marine vessels, rail, oil and gas, ag fertilizer, ag livestock, agricultural burning), it is
strongly recommended that S/L/Ts provide timely responses on requests for activity data, for review of draft
methods, and other comments they may have on EPA-provided information. Please note that we have still
spread out the work needed for collaboration on the nonpoint sectors and have multiple expected completion
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dates for different sectors. The details on the EPA nonpoint tools and input activity submittals are provided in
Section 7.
We provide a refined schedule for releasing data in EIS, which precedes the public NEI release by several months
for the point, and mobile data categories. Because there are usually at least some minor late changes in data,
EIS release data should be regarded as "draft" until the public release data for the NEI. We provide the EIS data
early with caveats because some data category inventories will be in their near-finalized state and thus available
sooner than others, and because it takes a few weeks to build all data summaries and documentation that
accompany the public release of the complete NEI. Only S/L/T and EIAG inventory developers, Regional Planning
Organizations, EPA Regional Offices, and other EPA users have access to the EIS datasets, which are available in
EIS when "finalized" but before public website dissemination can occur.
Comments on draft 2023 NEI data will be focused on issues identified by EPA quality assurance. We do not
permit S/L/T responses to these comments to be wholesale replacement data for an entire data category. In the
past, allowing wholesale replacements had the unintended effect of delaying the NEI release by many weeks or
months and needlessly increasing EPA costs and workload. S/L/T agencies will still be able to send data
corrections during a QA period. We are not including a placeholder for a second version ("v2") of the 2023 NEI,
since it is unlikely that a version 2 of the 2023 NEI would be scheduled after the full NEI release in March 2026.
Table 2-2: 2023 NEI Schedule for the Point Data Category
Item: Point
Who
Details
Deadline
Submission Window Opens for S/L/T
submittals
S/L/T
Point submittal window will open by 3/1/2024
to accommodate CAERS submitters.
3/1/2024
EPA 2023 landing/takeoff (LTO) data
available for S/L/T review period
EPA
On 2023 NEI Documentation website or
SharePoint
8/30/2024
S/L/T comments on EPA LTO data due
S/L/T
10/30/2024
EPA loads 2023 TRI data into EIS
EPA
The October 2024 TRI data that is used for the
annual TRI National Analysis Report in Spring
2025 is loaded to matching EIS facilities
11/30/2024
S/L/Ts and EPA ROs review the on-line
Point Data Completeness Report on
EIS Gateway
EPA
All facilities listed as "OP" should have
emissions reported or be in process of being
reported. Update operating statuses as
necessary
12/1/2024
S/L/Ts last day for submittal of Facility
Inventory edits to EIS
S/L/T
EPA closes Facility Inventory window on
1/9/2025
1/9/2025
S/L/Ts last day for submittal of Point
emissions to EIS
S/L/T
Any submittals after this date will not be
evaluated for Completeness Report feedback
and are not guaranteed to be accepted into
the 2023 NEI.
1/15/2025
EPA loads EPA-estimated 2023 EGU
emissions to EIS
EPA
1/15/2025
EPA sends final completeness report
to S/L/Ts, Regional Offices and Air
Directors
EPA
2/15/2025
S/L/Ts review completeness and
outliers reports and submit edits to EIS
EPA
Completeness and outlier checks
3/31/2025
2023 NEI draft Point Release in EIS
EPA
Draft point selection used to begin air toxic
screening modeling
4/1/2025
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Item: Point
Who
Details
Deadline
2023 Final NEI Point Release in EIS
EPA
Incorporates edits made by S/Ls in EIS and
comments submitted based on draft air toxic
risk modeling
2/28/2026
Table 2-3: 2023 NEI Schedule for the Onroad and Nonroad Mobile Data Categories
Item: Mobile
Who
Details
Deadline
Post instructions and 2023 default inputs
for onroad and nonroad
EPA
On 2023 NEI Documentation website or
SharePoint
8/1/2024
EPA sends reminder to S/L/Ts and Regional
Offices to review EIS Completeness Reports
EPA
Except for California, states required to
submit MOVES inputs. See checklist of
data in Section 3.3.3
12/1/2025
S/L/Ts last day for submittal of
Onroad/Nonroad activity input data to EIS
S/L/T
S/L/T provides CDB tables or notifies EPA
to use EPA default data
1/15/2025
EPA sends final completeness report to
S/L/Ts, Regional Offices and Air Directors
EPA
Share record of CDB submittals
2/15/2025
EPA provides feedback to S/L/Ts on data
quality and outliers
EPA
Window open on a case-by-case basis for
activity data corrections only
5/1/2025
S/L/T corrections based on EPA feedback
due
S/L/T
Activity data only
7/1/2025
EPA solicits corrections on case-by-case
basis
S/L/T
Starting May 15, 2025
7/31/2025
2023 NEI release in EIS
EPA
9/15/2025
Table 2-4: 2023 NEI Schedule for all Fires
Item: Fires
Who
Details
Deadline
Inform S/L/Ts on our overall plans for
methods changes in the 2023 NEI for
WLFs
EPA
-Provide details on proposed changes
6/30/2024
EPA to request 2023 activity data from
S/L/Ts and other local organizations.
S/L/T
The current plan is for EPA to provide
instructions on how to submit activity to EIS.
This includes activity for wildland fires and
agricultural burns.
8/1/2024
Activity data and questionnaire due
back to EPA
S/L/T
Due date for activity data submitted to EIS.
Questionnaire will be a separate document to
submitted directly to EPA staff.
12/15/2024
Initiate fires workgroup
EPA
Collaborative workgroup on emissions
inventory development process with calls at
regular intervals
8/15/2024
Provide draft daily acres burned and
emissions estimates based only on
default fire occurrence and activity
data along with documentation.
EPA
Documentation will include the methodology
used to generate the draft Bluesky Pipeline
(BSP) emissions estimates. Draft estimates will
include agricultural burns and the
methodology used create these emissions.
9/1/2024
EPA sends initial submittal status to
S/L/Ts and Regional Offices
EPA
Indicate whether S/L/Ts submitted emissions,
activity data, or approved of EPA estimates;
"completeness" definition differs from other
12/30/2024
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Item: Fires
Who
Details
Deadline
source categories since fires submittal is not
required by AERR.
Review of draft BlueSky Pipeline
wildland fire and agricultural burn
emissions estimates
S/L/T
Due date to submit new inputs and/or
comments on draft estimates and methods,
per the data disseminated on 9/1/2024
12/15/2024
EPA communicate with S/L/Ts on the
quality of the submitted activity data
EPA
This includes comments on activity data,
answering questions about draft estimates,
and cleansing the data so that we can use for
final emission estimates
12/15/2024
- 3/15/2025
EPA sends final submittal status email
to S/L/Ts, Regional Offices and Air
Directors
EPA
"Completeness" definition differs from other
source categories since fires submittal is not
required by AERR.
2/15/2025
EPA posts revised data and
documentation outlining changes from
draft
EPA
Will reflect suggested revisions/comments
from draft review as resources allow
5/15/2025
Final fire emissions results review by
S/L/Ts
S/L/T
Only minor changes will be allowed at this
stage of process due to resource limitations
7/15/2025
Develop final EPA-based WLF and
agricultural burn emission estimates
for the US, including final
documentation, including updated
trends, and data parsed by tribal land
EPA
These will be the final EPA estimates. See
Section 9
8/15/2025
2023 NEI release in EIS, public release
to follow a month later
EPA
9/15/2025
Table 2-5: 2023 NEI Sd
leduleforthe Nonpoint Data Category
Item: Nonpoint
Who
Details
Deadline
Post list of nonpoint sectors where
EPA will develop estimates, including
any new methodology, along with
2023 activity data availability
EPA
See Section 7.3
7/31/2023
Final new methodologies provided to
S/L/Ts
EPA
Discussed during NOMAD committee calls and
posted on SharePoint.
5/1/2024
Comments on new methodologies to
EPA
S/L/T
Upload your comments to NOMAD SharePoint
folder
6/1/2024
EIS Nonpoint Survey is opened with
rest of S/L/T submittal windows
EPA
See Section 7.5
7/1/2024
EPA provides status update on all
HAP Augmentation factors in EIS.
These factors will be used to
generate all nonpoint HAPs that
aren't included in EPA tools or
submitted by S/L/Ts.
EPA
The Wagon Wheel for 2023 will not produce
VOC HAPs (same as 2020). So, S/L/Ts that use
the WW to "test" for emissions can estimate
resulting HAPs via these factors.
7/1/2024
All draft input templates available in
EIS
EPA
Should closely resemble 2020 Input templates
except for any new features (via NOMAD
discussions) that have been put in place. Note
7/1/2024
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Item: Nonpoint
Who
Details
Deadline
that not all default data is finalsee activity
data tracker in Section 7.3 for more details.
First Wagon Wheel Release
EPA
See activity data tracker (Section 7.3) for
details
7/31/2024
EPA provides all CMV and rail
estimates
EPA
11/15/2024
EPA sends reminder to review EIS
Completeness Reports to S/L/Ts and
Regional Offices
EPA
Nonpoint Survey summary report, list of
submitted Input Templates, and list of sources
with emission submittals
12/1/2024
Second Wagon Wheel Release
EPA
1/31/2025
EPA provides default input templates
from S/L/T point emissions
EPA
For solvents, gas distribution stage 1, POTW,
and draft ICI fuel combustion
2/15/2025
S/L/T deadline for submitting ALL
portions of Nonpoint Survey (end of
nonpoint grace period)
S/L/T
Ensure the Survey is marked as "Complete"
(green button) in EIS, under "Nonpoint Survey"
3/31/2025
EPA sends final Completeness Report
to S/L/Ts, Regional Offices and Air
Directors
EPA
Nonpoint Survey summary report, list of
submitted Input Templates, and list of sources
with emission submittals
4/30/2025
EPA provides feedback to S/L/Ts on
data submissions
EPA/
S/L/T
Window open on a case-by-case basis for
emissions only. We will note where S/L/Ts
submitted acceptable inputs rather than
emissions
7/1/2024-
9/30/2025
EPA posts WW tool reflecting all
S/L/T-submitted inputs
EPA
includes S/L/T inputs submitted through
3/31/2025. Some (default) activity data
updates are possible through the end of 2025.
9/1/2025
Third Wagon Wheel Release
EPA
7/31/2025
Inputs for third Wagon Wheel due
S/L/T
Limited to SCCs covered by tool activity data
updated in Wagon Wheel V3
8/31/2025
Emissions and documentation for
third wagon wheel due
S/L/T
Limited to SCCs covered by tool activity data
updated in Wagon Wheel V3
9/30/2025
Completeness reports sent to S/L/Ts
and ROs for nonpoint only
EPA
This is to accommodate the third Wagon Wheel
release late date and will not be sent to Air
Directors
10/15/2025
Release Draft NP selection in EIS for
all nonpoint
EPA
Should be close to final NEI except for some
late-breaking activity data
10/31/2025
S/L/T provides corrections on case-
by-case basis, starting 5/15/2025
S/L/T
S/L/Ts do not need to submit updated Input
Templates. EPA will load the "latest available"
data in late 2024.
11/30/2025
Placeholder for 4th Wagon Wheel
release
EPA
Reflects all final EPA and S/L/T input templates
and additional tool corrections
12/15/2025
2023 NEI Release in EIS for all
nonpoint
EPA
Reflects all S/L/T data, including point
inventory subtraction from input templates
2/28/2026
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3 Best Practice Recommendations for SIT Inventory Developers
The section focuses on key items for S/L/Ts to consider when developing their inventories. It includes suggested
timelines for activity, AERR requirements and best practices to follow. In addition, it will explain how pollutants
will be evaluated for inclusion, exclusion, and/or supplementation by data category. Lastly, it will explain how
data corrections will be handled between EPA and S/L/Ts.
3.1 Suggested SLT Inventory Development Schedule and EIS QA Checks
To assist you in allocating your time and resources to complete this requirement, we are including a suggested
timeline by data category, Table 3-1 for the point inventory, Table 3-2 for the stationary sources in the nonpoint
data category, Table 3-3 for commercial marine vessels and rail, Table 3-4 for onroad mobile and nonroad
mobile data category sources, and Table 3-5 for fires.
Table 3-1: Suggested S/L/T Schedule for Point Inventory Development
Date
Activity
11/1/2023 - 3/1/2024
Update your data system to include new and changed reporting codes and QA checks to
match what is in EIS.
3/1/2024 -11/1/2024
Run EIS Facility Configuration reports and compare to your local system to ensure IDs
still match and to identify new facilities, units, processes, release points that need to be
created in EIS.
3/1/2024 -11/1/2024
Develop facility inventory submission to update EIS with changes to status, new facilities,
units, processes and release points.
3/1/2024 -11/1/2024
If using staging tables; run embedded queries to check for widows and orphans prior to
conversion
3/1/2024-11/1/2024
Submit facility inventory data to the EIS QA Environment. Check Potential Duplicates
section of feedback report and resolve any real duplicates as opposed to actual new
facilities that need to be added. Revise or add facility IDs in EIS as needed to allow EIS to
recognize the correct facility when you submit to Production.
3/1/2024 -11/1/2024
Check number of facility, unit, process, and release point records received on the
Statistics tab of feedback report against number of records submitted.
3/1/2024 - 11/1/2024
Resolve all critical errors in facility feedback report
3/1/2024 -11/1/2024
Submit facility inventory data to the EIS Production Environment. Note that you only
need to submit data for items that have changed between your system and EIS. Existing
facilities and units and release points do not need to have locations, unit types, release
parameters, etc. reported to EIS each year if they are already in EIS and acceptable. If
your system does not contain information on unit type or other data fields in EIS, do not
include those fields in your submittal with "unclassified/miscellaneous" for existing
facilities.
3/1/2024 -11/1/2024
Check Potential Duplicates section of EIS and resolve any issues by contacting EIAG to
add or merge facilities.
6/1/2024- 12/31/2024
Download landing/takeoff data for review from 2023 website, available 6/30/2024
6/1/2024- 12/31/2024
Develop emissions (point) inventory for submission to EIS
6/1/2024- 12/31/2024
Submit point inventory to the EIS QA Environment
6/1/2024-12/31/2024
Check number of reporting period and emission records received on the Statistics tab of
the feedback report against the number of records submitted.
6/1/2024- 12/31/2024
Check EIS feedback report and resolve all critical errors
6/1/2024-12/31/2024
Review emission range warnings in EIS feedback report for possible outliers or incorrect
entry
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Date
Activity
7/1/2024- 12/31/2024
Submit data to the EIS Production Environment
10/1/2024 -12/1/2024
Run suggested QA reports in the Suggested QA Checks for S/L/T Point Inventory
Development (Table 3-6)
10/1/2024 -12/1/2024
Review Completeness and Outliers Report to verify everything has been submitted and
check feedback reports and run summary EIS reports to ensure everything has been
loaded into EIS as expected
12/1/2024 -1/15/2025
Address any last-minute adjustments (remember facility window closes 1/9/2025)
Table 3-2: Suggested S/L/T Schedule for Stationary Nonpoint Inventory Development
Date
Activity
Now - ongoing
Join NOMAD committee to attend monthly workgroup calls -generally 3rd Wednesday
each month at 2pm Eastern Local Time. Email Lindsav Davton to be added.
11/1/2023 - 3/1/2024
Update your data system to include new and changed reporting codes and QA checks to
match what is in EIS.
6/15/2024
Download expected pollutants list from SharePoint
6/1/2024 - 12/1/2024
Submit data to the EIS QA Environment
6/1/2024 -12/1/2024
Check number of emission process, reporting period and emission records received on
the Statistics tab of feedback report against the number of records submitted. The
statistics should equal
6/1/2024 - 12/1/2024
Resolve all critical errors in feedback report
6/1/2024 - 12/1/2024
Review emission range warnings for possible outliers or incorrect entry
6/15/2024-3/31/2025
EIS submittal window open for all nonpoint emissions and nonpoint survey submittals
and SharePoint for nonpoint input templates
8/1/2024-1/1/2025
Download first version of the 2023 Wagon Wheel, review draft activity data, run tool for
your agency, determine if you plan to accept EPA estimates for Nonpoint Survey, or
develop your own inputs or emission estimates. Note that most activity data will be
updated prior to final NEI but estimates should be "close".
7/1/2024-3/31/2025
Submit, if not accepting EPA inputs/emissions, to SharePoint any inputs to EPA Wagon
Wheel using provided templates
9/1/2024-3/31/2025
Review Nonpoint Survey in EIS; determine which sectors will be submitted to EIS and
which sectors you will accept EPA estimates/inputs
10/1/2024 - 3/1/2025
Run suggested QA reports listed in the Suggested QA Checks for Nonpoint Inventory
Development (Table 3-7)
10/1/2024-3/31/2025
Run completion report to verify everything has been submitted
2/1/2025-3/31/2025
Download second version of the 2023 Wagon Wheel, review draft activity data, run tool
for your agency, determine if you plan to accept EPA estimates for Nonpoint Survey, or
develop your own inputs or emission estimates. Note that most activity data will be
updated prior to final NEI but estimates should be "close".
3/31/2025
Submittal deadline for most nonpoint sources: emissions, input templates, and the
nonpoint survey
8/1/2025-8/31/2025
Download third version of the 2023 Wagon Wheel -contains final default activity data.
Review activity data, run tool for your agency, determine if you plan to develop your
own inputs or emission estimates for the updated sources only.
8/31/2025
Due date for submitting updated input templates for only those sources updated in the
third version of the wagon wheel.
9/30/2025
Due date for submitting emissions and documentation for only those sources updated in
the third version of the wagon wheel.
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Date
Activity
9/1/2025-11/30/2025
Respond in a timely fashion (ideally under 2 weeks) to quality assurance issues provided
by EPA: input templates and emissions
Table 3-3: Suggested S/L/T Schedule for Commercial Marine Vessels and Rail
Date
Activity
Now-indefinite
Rail and CMV emissions estimates will be posted to the NEI SharePoint for review.
Instructions on where to send comments will be included. Announcement of availability
will be made via the NEI newsletters and NOMAD calls. Additionally, CMV methods and
updates on EPA developed emissions are discussed on MARAMA CMV calls and
interested parties are encouraged to attend; contact Janice Godfrey to be added to
these calls.
6/15/2024
Download expected pollutants list from SharePoint
6/15/2024 -12/1/2024
If choosing to NOT use EPA estimates, submit emissions to EIS QA Production
6/15/2024 -12/1/2024
If choosing to NOT use EPA estimates, resolve all critical errors in EIS feedback report
7/1/2024 - 1/1/2025
If choosing to NOT use EPA estimates, submit to EIS Production Environment
9/30/2024
Download commercial marine vessel shapefile fractions from 2020 website (line rail will
be at county, not shape level for 2023 NEI)
1/15/2025
Due date to submit CMV and rail emissions
2/15/2025 - 4/15/2025
Download draft EPA CMV data, summaries, and documentation from SharePoint.
Review, and provide comment to EPA on draft EPA CMV data
4/15/2025
Due date to provide comments to comments to EPA on draft EPA CMV data
4/15/2025 - 6/15/2025
Download draft EPA rail data, summaries, and documentation from SharePoint. Review,
and provide comment to EPA on draft EPA rail data
6/15/2025
Due date to provide comments to comments to EPA on draft EPA rail data
Table 3-4: Suggested S/L/T Schedule for Onroad and Nonroad Mobile Inventory Development
Date
Activity
Now-indefinite
Join MJO-MOVES workgroup if interested. EPA methods and updates are provided on
calls. Generally, the 3rd Thursday each month at 2pm Eastern Local Time. Click here to
register.
6/1/2024 - 12/1/2024
Download onroad and nonroad inputs and instructions from the EIS Gateway
6/1/2024 - 12/1/2024
Adjust inputs (e.g., VMT, inspection maintenance, etc.)
6/1/2024 - 12/1/2024
Package submission according to instructions posted on 2020 website
6/1/2024 - 12/1/2024
Run QATool posted on 2023 website
6/1/2024 - 12/1/2024
Submit to EIS QA Production
6/1/2024 - 12/1/2024
Resolve all critical errors in EIS feedback report
7/1/2024 - 12/1/2024
Submit to EIS Production Environment
12/1/2024 -1/15/2025
Address any remaining adjustments
Table 3-5: Suggested S/L/T Schedule for Fires
Date
Activity
8/15/2024-5/15/2025
Join Fires workgroup if interested, attend calls to understand EPA methods and provide
comments on process via questionnaire. Email Lindsay Dayton to be added to the
workgroup.
8/1/2024-12/15/2024
Work on questionnaire sent by EPA and work on submitting fire activity to EIS including
wildland and agricultural fires.
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Date
Activity
12/15/2024
Due date for submitting all fire activity data to EIS and questionnaire to EPA staff
9/1/2024
Download SMARTFIRE2-Blueksky draft wildland fire and agricultural burn emissions
results from a NEI 2023 folder on EPA's ftp website. Specific directory location will be
provided by EPA.
9/1/2024 - 12/15/2024
Provide comments on draft fire inventory data
5/15/2025-7/15/2025
Final wildland fire and agricultural burn emissions data results review
Table 3-6 provides suggested S/L/T EIS QA checks for the point inventory, and Table 3-7 for the nonpoint
inventory development process. These are additional suggested QA checks, beyond the expected review of any
warnings and errors provided in EIS feedback reports for submitted facility or emissions inventories. To best take
advantage of these reports, your data will need to have been submitted early enough that you can check for
data quality and adjust your previously submitted file. For nonpoint data, use the information in Section 7.3 to
leverage the availability of EPA data with year 2023 activity input data for certain nonpoint categories; you can
get a "near-final" EPA default estimate after EPA loads 2023 activity data to the nonpoint tools.
Table 3-6: Suggested QA Checks for S/L/T Point Inventory Development
Type
Report
Type
Dataset(s)
Pollutants
Geographic
Region
Checks
Emission
Summary -
By
Geography
State or
County
Level
Your Agency
Dataset
All Active
Pollutants
Your State,
County or
Tribe
Check that state/pollutant combination
totals in EIS equal the state/pollutant
combinations that you intended to
submit to EIS. This will assure that a) all
your emissions data successfully made it
into the xml file, and b) all the xml data
were accepted by EIS. If there are
significant differences, run a facility or
unit or process level EIS report and
compare to your system's summaries to
EIS summaries to identify the source of
the differences.
Comparison -
Facility
Facility
Level
Your current
Agency
Dataset;
2020 Agency
Dataset;
2020 NEI
All Active
Pollutants
Your state,
county or
Tribe
Compare your 2023 submitted and
accepted emissions to either your 2020
submission or to the 2020 NEI. Look for
large differences which might indicate
reporting errors. Check that all
pollutants reported in 2020 have been
reported in 2023.
Emission
Summary -
By Facility
Facility
Level
Your Agency
Dataset
All Active
Pollutants
Your state,
county or
Tribe
Sort for Top 25 facilities for each
pollutant reported. Do they make
sense?
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Table 3-7: Suggested QA Checks for S/L/T Nonpoint Inventory Development
Type
Report
Type
Dataset
Pollutants
Geographic
Region
Checks
Input
Template
QA
S/L
Feedback
You Agency
Input
Template
N/A
Your
agency
Review EIS feedback report for
identified outliers (vs EPA defaults)
Emission
Summary -
By
Geography
S/L/T by
Sector
Your Agency
Dataset
All Active
Your state,
county or
Tribe
Check that the state (county or
Tribe)/sector/pollutant in EIS are the
same as the file you submitted. If there
are differences, run the same report at
the SCC level until you can highlight
where the differences are coming from.
Emission
Summary -
By Source
Category
S/L/T by
see
Your Agency
Dataset;
2023 draft
EPA
All Active
Your state,
county or
Tribe
Check that the state (county or
Tribe)/SCC/pollutant in EIS contain all
expected pollutants and do not include
unexpected pollutants. Compare to
EPA draft estimates; if there are
significant differences vs EPA
estimates, determine whether they are
valid or ask EPA to review.
Comparison
Sector
Your current
Agency
Dataset;
2020 Agency
Dataset
All Active
Your state,
county or
Tribe
Compare your 2023 submission to your
2020 submission. Check that all
pollutants and sectors reported in 2020
have been reported in 2023 (if you
intended to report in 2023). If there are
differences, run the same report at the
SCC level to determine the location of
the erroneous or missing data.
3.2 AERR
A significant change to the 2017 NEI was enforcing the AERR requirement (via Table 2b to Appendix A of Subpart
A in 40 CFR 51.30) for throughput data necessary for computing nonpoint fuel combustion from industrial and
commercial/institutional (ICI) sources. We are again enforcing this for the 2023 NEI and it will be a part of the
Completeness Reports.
3.2.1 Point Inventory
Please refer to 40 CFR Part 51, Subpart A for the point source submission requirements. Key requirements for
your attention include:
The data fields required by the AERR are provided in Table 2a and 2b to Appendix A of the AERR. The
field definitions are provided in Section 51.50 of the AERR.
The point source reporting thresholds are specified as part of Section 51.50 definition of point sources.
The emissions thresholds are specified as "potential to emit" emissions (except for lead) and are lower
for sources within nonattainment area boundaries for ozone, PM10, PM2.5, and CO nonattainment
areas. The reporting threshold for lead emissions as point sources is 0.5 tons per year of actual
emissions.
Although the reporting thresholds are potential to emit, actual emissions are required to be reported.
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Startup and shutdown emissions are considered routine and should be included with your reported
emissions (these emissions may be optionally denoted separately with the XML schema, but doing so is
not required)
3.2.2 Nonpoint Inventory
Please refer to 40 CFR Part 51, Subpart A for the nonpoint source submission requirements. Key requirements
for your attention include:
The data fields required by the AERR are provided in Table 2b to Appendix A. While EIS does not enforce
the reporting of all required data fields, air agencies are legally obligated to report the required fields.
The field definitions are provided in Section 51.50 of the AERR.
Obtain the latest reporting codes from EIS prior to compiling nonpoint source data. For the 2023 NEI
cycle, some codes will change (see Section 4.1).
We are again extending the S/L/T submittal deadline for the Nonpoint Survey and most stationary nonpoint
emissions and some wagon wheel input templates, to March 31, 2025. These deadlines are well beyond the
January 15, 2025, extended-AERR deadline. We believe the extended deadline for the nonpoint data category,
particularly for sources that rely on point inventory activity or emissions data, allows for improved estimates via
more updated activity data and more accurate point source subtraction.
In addition, new for the 2023 NEI, we are further extending the submittal deadline for version 3 Wagon Wheel
sources inputs/emissions to August 31/September 30, 2025, respectively.
The EPA Wagon Wheel no longer supports nonpoint ICI emissions computed from point inventory emissions
subtraction. However, we will again support flexible reporting options for S/L/Ts in the form of point activity
data that can be used to reconcile with overall fuel consumption data from the Energy Information Agency (EIA).
We will also work with local and state agencies that do not cover the entire state to craft nonpoint ICI estimates
for their specific counties of responsibility. More information on this requirement is discussed in Section 7.7. It is
important to note however, that the nonpoint (or point) ICI input activity data is not required if S/L/Ts submit
nonpoint ICI emissions directly to EIS (by September 30, 2025).
3.2.3 Mobile Inventory
For onroad and nonroad, state and local agencies are required to submit MOVES model county data bases (CDB)
inputs. They may choose to submit emissions in addition. The exceptions are tribes and California, who may
submit emissions only.
3.3 Best Practices; How Should I Submit My Data?
For every data category, we have the following recommendations:
Plan to start your submission process at least 4-8 weeks prior to the deadline, accounting for time away
from the office for holidays.
When submitting emissions, do not submit zeroes unless you know those pollutants are not emitted
from those processes/SCCs. It is not necessary to submit zeros for entire SCCs or counties. Additionally,
submitting zeros can cause issues in the NEI selection due to EIS Option Group Option Set (OGOS) rules.
See Section 7.8 for information on OGOS. Use the nonpoint survey to indicate if your agency does not
have emissions for certain SCCs or does not want to backfill additional counties. See Section 7.5 for
more information.
Submit data to the EIS QA Environment prior to submitting data to the Production Environment and
make sure your feedback reports are clean prior to submitting to the Production Environment.
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Use EIS comparison reports as an additional QA step (see Section 10.3) to compare emissions to the
previous NEI, latest available EPA data, as well as your previous inventory submittal(s).
For particulate matter, please provide both PM10-PRI and PM25-PRI, and PM-CON if you can, or
equivalently provide PM10-FIL, PM25-FIL, and PM-CON. You can report all five PM pollutants but note
that EIS QA checks will verify their arithmetic. If you cannot provide complete data, EPA will fill those
gaps where needed by PM Augmentation within EIS.
Verify that the emission totals in EIS agree with what you have in your agency's data system after
submission to EIS Production.
Run the EIS Completeness Report and update your submission to meet or exceed all completeness
criteria.
3.3.1 Point Inventory
The EPA encourages the use of the following best practices when submitting emissions of point sources.
Collecting data from facilities:
o Request that facilities use stack test data, material balances, or other site-specific and reliable
calculation methods to estimate emissions for their processes. Where such methods are not
available, facilities can use the best available emission factors for similar processes,
o Require that facilities use the latest EIS reporting codes. Download these as described above and
make them available to your facilities,
o For HAPs, encourage facilities to compare their HAP submissions to what has been submitted to
TRI. While the EPA prefers the State-reported HAP emissions for the NEI because they should be
at a more detailed process level, the facility-level TRI data and State-reported process-level data
should sum to the same values. States should NOT report facility total HAPs to separate non-
integrated process IDs, and States should NOT report TRI facility-level totals as their own data,
o Do not use EPA's HAP Augmentation ratios or other means to report HAPs for a facility unless
you are confident that you are accounting for all significant sources of any given pollutant for a
facility in your submittal. Reporting only a portion of the HAPs for a facility in your Agency's EIS
submittal will result in the TRI or other EPA dataset values for that HAP not being considered for
selection for that facility, even though those other datasets might provide a much more
complete accounting of that HAPs emissions than the HAP Augmentation approach.
Building your inventory:
o Use consistent identification codes from one year to the next (e.g., facility, unit, release point,
and process identifiers). This prevents the creation of duplicate facilities or sub-facility records,
which reduces the potential for double-counted emissions to be introduced either in State-
reported data or due to the use of TRI or CAMD values. If needed, work with your information
technology department to identify ID changes that have been made in your data system and
update your agency IDS in EIS.
o Provide control information whenever possible, making sure that it is complete. The control
data are required by the AERR (when controls are present), and the EPA uses the control data to
assess future possible controls as a demonstration of whether and how future NAAQS can be
attained.
Reporting best practices:
o If possible, submit the facility inventory data for only those facilities or parts of facilities that
have changed since the previous time the facility inventory data were provided,
o Make sure to also submit updates to the "Operating Status Code" for facilities that are no longer
operating or no longer required to report as point sources. This will impact your completeness
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report since facilities which have a Facility Site Status Code of OP (Operating) that have not
submitted emissions will be counted as incomplete.
3.3.2 Nonpoint Inventory
The EPA encourages the use of the following best practices when submitting emissions of nonpoint sources.
EPA's nonpoint emissions tools and input templates:
o EPA encourages S/L/T agency staff to participate in the review and development of the nonpoint
emissions tools, datasets, input templates for the tools, and methodologies. The EPA will be
continuing Nonpoint Method Advisory (NOMAD) workgroups focused on method improvements
and documentation in the tools, with particular focus on how to best obtain S/L/T-submitted
activity data where available,
o Focus on the expected delivery dates for nonpoint activity data (see Section 7.3): some default
input data for year 2023 will be available much sooner than other, so you will be able to obtain
activity for nonpoint source categories at different timeframes,
o After the tools/datasets and input templates are released, the EPA encourages states to review
the available documentation and use the input templates to estimate their emissions. S/L/Ts can
directly load their input activity data in the Wagon Wheel and compare emissions to the default
data. Alternatively, if no changes are needed to these EPA defaults, S/L/T air agencies can
indicate to EPA (through their nonpoint survey response) their interest in allowing the EPA
defaults to supplement their NEI emissions estimate.
Provide an accurate and timely nonpoint survey response.
Building your inventory:
o Do not use old inventory documentation for nonpoint categories (e.g., hospital sterilizers).
Instead, use the methodologies outlined in the 2020 NEI Technical Support Documentation, new
methodology documents provided for the 2023 NEI on SharePoint, or, your own approach based
on current information (your emission factors and activity data),
o Provide control information whenever possible, making sure that it is complete. The control
program data are required by the AERR (when control programs are present), and EPA uses the
control data to assess future possible controls as a demonstration of whether and how future
NAAQS can be attained,
o Use the expected pollutants list (see Section 3.4.2) to help ensure complete coverage and
reduce mixing of EPA and S/L/T-submitted data where possible,
o Use the information provided to EPA in the 2023 nonpoint survey (see Section 7.5) to make sure
to report those categories that you indicated you have in your state,
o Focus on categories that require point/nonpoint reconciliation since the EPA can only estimate
point emissions/throughput based on what S/L/Ts directly submit. EPA will develop default
point emissions data for subtraction for all nonpoint sectors that rely on it; however, the ICI tool
requires point activity (fuel consumption) data and therefore, submitting an ICI input template is
critical. For ICI, the default point fuel consumption estimates provided by EPA are based on
throughputs submitted by only those states that submit point input data and are therefore a
gross approximation for a non-submitting state's point fuel consumption. These efforts will help
prevent missing emissions or double counting of emissions.
Reporting best practices:
o Identify as early in the process as possible, those nonpoint sources that are most important for
your agency and which sources you prefer to not accept EPA estimates.
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o Focus on ICI fuel combustion, specifically, collecting point inventory fuel consumption data for
point subtraction. For the 2020 NEI, EPA developed a default methodology for subtracting S/L/T
point inventory fuel consumption data based on S/L-submitted ICI Input templates for point fuel
consumption. For the 2023 NEI, we will regenerate these defaults AFTER the 2023 submittal
window closes (August 31, 2025); however, the quality of this default approach is: 1) directly
related to a critical level of valid year-2023 S/L-submitted templates across all ICI fuels and
sector combinations, and 2) will not be representative as direct S/L information. Regardless, it is
critical to avoid possible double counting of ICI point/nonpoint that S/Ls submit either ICI Input
Templates, or direct nonpoint ICI emissions. For S/L agencies that do not cover the entire state,
there will need to be either emissions submitted, or a review of draft submitted throughputs
versus EIA SEDS and ICI tool estimates.
Refer to the Nonpoint Cheat sheet located on the NOMAD SharePoint site for helpful links, references,
and requirements.
3.3.3 Mobile Inventories
The EPA encourages the following best practices when submitting onroad/nonroad mobile data:
Join the monthly MJO-MOVES Sessions for information of latest inventory development issues.
Look for and follow posted directions on how to submit mobile inputs. Inputs are required for all sources
in MOVES: all onroad vehicles and nonroad equipment.
Submit both the required input data, and any supplemental documentation, to help support and explain
your input information. The EPA will provide instructions regarding how to provide any supplemental
documentation prior to the June 2024 opening of the EIS submission window.
States may submit county CDBs for just vehicle miles traveled (VMT) and vehicle population (VPOP); or
they may choose to submit additional county inputs (e.g., age distributions, VMT fraction (by month,
day, and hour), average speed distributions, hourly average speeds, starts, and hoteling).
Best practices include (but are not limited to):
o Pulling age distribution fractions from your state DOT mid-year to get an appropriate mix of
older vs. newer vehicles.
o Speed distributions should reflect AM and PM congestion peaks. Weekday distributions should
be the same as the weekend profiles,
o If the VMT/VPOP ratio is too high (e.g., a rural county with little registered VPOP, but an
interstate highway supplying high VMT), negative emission factors can result. Care should be
taken to increase the VPOP to ensure good model results,
o VMT fraction should vary by vehicle type and time of day, with peaks during high traffic times of
the day.
o State and local agencies do not populate their submitted CDBs with MOVES default data.
3.3.4 Fires Inventory
Participate in planned workgroup meetings/conference calls. The workgroup will focus on wildland fire
and agricultural burn emissions.
Submit activity data so that the EPA does not have to use default data to identify and estimate emissions
from fires occurring in your domain. Important parameters include acres burned, fire
location/perimeters, start and ending times, fuel loading, and fuel consumption; however, acres burned
is the most important activity data to submit. The activity will include wildfires, prescribed burns, and
agricultural burns. The EPA relies on the default methods from satellite detections without more specific
data. The importance of submitting activity data is especially true for prescribed fires because the EPA
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methods have a difficult problem identifying which fires are prescribed fires. At this time, we hope that
activity data for the 2023 NEI fires will be submitted via the EIS Gateway. EPA will provide directions if
those plans change.
Review draft NEI for Fires (including wildland fires and agricultural burns) soon after it is available.
Ensure that submitted activity data were used appropriately. Provide comments in the comment time
period specified in Table 3-5.
If an Agency decides to submit actual fire emissions, provide documentation on the methods as much as
possible.
o For wildland fires, the Agency must submit day-specific, location-specific data suitable for use in
air quality modeling platforms. Also, if an Agency submits emissions, ensure that the pollutant
coverage is the same as what the EPA estimates using its methods. If emission factors are
needed, please contact the EPA. The emissions data format used in previous NEIs for EIS Events
can be submitted but SMOKE-ready format (FF10) is also acceptable. Please contact Jeff
Vukovich via email to make emissions data submittals. EPA will take the day-specific, location-
specific inventory supplied by an Agency and sum emissions by month and county and submit
the emissions to the EIS nonpoint database. An Agency will not be able to submit wildland fire
emissions directly to the EIS nonpoint database,
o For agricultural burns, the agency can continue to submit emissions directly to the EIS nonpoint
database; however, ideally, similar to wildfires and prescribed burning, additional submittal of
day and location-specific emissions (not in EIS) would be ideal. Reporting of activity data for
agricultural burns is required.
Please plan on reviewing the draft estimates that will be provided by EPA and submitting appropriate
comments. In addition, please work with EPA to submit and review your activity data as EPA processes
them into emissions.
Please inform EPA if you plan to accept EPA estimates anytime in the process.
3.4 Expected and Allowable Pollutants and Conditional Exclusion of SLT data
Like the 2020 NEI, EPA will provide a list of expected CAPs and HAPs by process (SCC) for the county-aggregate
emissions data categories. Expected pollutants for these data categories are those that EPA calculates using its
own estimation methods. While other pollutants can be reported by S/L/Ts, we would prefer that S/L/Ts who
have pollutants outside of the expected pollutants list contact the NEI Team so that we can accommodate a
complete list of EFs to use, and pollutant coverage is consistent throughout the US. For point sources the
expected pollutants are defined at the facility level, and those pollutants are used as part of the Data
Completeness and Outliers Report.
We do not plan to add GHGs to any expected pollutant lists even though we allow for their submittal in EIS. For
the 2023 NEI cycle, the EPA will be starting with a similar list of expected pollutants for both point and nonpoint
sources that we've generated in the 2020 NEI cycle. In general, when EPA estimates emissions for a source, the
expected pollutants are those that EPA estimates for those sources. While the list of allowable pollutants is a
bigger set, submitting pollutants that are not expected could result in EPA tagging them out. Some new
nonpoint SCCs are expected, and EPA will provide an updated expected pollutant list from that used for the
2020 nonpoint NEI prior to the submittal window opening on July 1, 2024. The current lists of expected
pollutants will be made available on the National Emissions Inventory website and NEI SharePoint site for the
county-aggregate data categories. Facility expected pollutants are available in EIS as a configuration report.
The reporting of criteria air pollutants (CAPs) is required under the AERR for all data source categories, while the
reporting of hazardous air pollutants (HAPs) is not. For the county-aggregate data categories (mobile and
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nonpoint data categories), EPA prefers that S/L/Ts DO NOT submit HAPs and instead allow EPA to augment
these pollutants using our methods for a consistent set of HAPs for all SCC. For point sources EPA prefers that
S/L/Ts do report HAPs wherever they have estimates. However, HAPs are critical to complete the NEI, and will
be supplemented by EPA if S/L/Ts do not provide complete data, and therefore, HAPs are also included in these
lists.
An important note on expected pollutants: If you are certain that a process does not have emissions for an
expected pollutant, then consider the following:
You are encouraged to submit a zero value for that pollutant; do not leave it as "null". Otherwise, a non-
zero value will possibly be picked up via EIS HAP or PM augmentation (generally on S/L/T-submitted
VOC, PM or S02 values), or another lower-hierarchy dataset. However, EPA may tag out your zero
value if the expected pollutant was reported to TRI.
For nonpoint sources, if you are submitting emissions (not Input Templates -see Section 7.4) you also
need to select "No" in the Nonpoint Survey to prevent EPA data from gap-filling this data.
For nonpoint sources, do not submit zero emissions for all pollutants for a process, but rather, use the
Nonpoint Survey to select "No". Doing so will prevent EPA estimates from backfilling and also avoid
unintentional OGOS (see Section 7.8) blocking of desirable emissions for higher option set assignment
SCCs.
An S/L/T's agency data submittal will not be considered unfinished (incomplete) if it does not voluntarily report
HAP emissions, but it will be augmented with EPA estimates of HAPs using EPA data augmentation procedures.
The purpose of the expected pollutants list depends on the data category. Each data category is discussed in the
following subsections.
3.4.1 Point
For point sources, the expected pollutants list indicates where the S/L/T agency or the facility itself via TRI
reports have reported non-trivial amounts of a pollutant for a facility in prior years. Expected CAP pollutants will
be used to determine if a facility is "Complete" if the facility as a whole is required to be reported for the
inventory year (triennial NEI years vs in-between years). Expected HAP pollutants are only used to calculate the
"% Expected HAPs" metric, because HAPs are not required to be reported. The expected pollutants for a facility
also include an expected range, and emissions values reported outside of those ranges are not counted as a
valid report. S/L/Ts should review and either revise emissions values that are out of range or contact EPA to
adjust the range if the reported values are confirmed to be correct.
S/L/T-submitted pollutants that are not in the expected pollutants list for point sources will usually be used in
the NEI. We may however tag out pollutants which are clearly not only not expected, but also nonsensical, such
as VOC or NOx emissions from rock crushing SCCs.
EPA will add HAPs to facilities where they are not reported by S/L/Ts by first using the TRI-reported data and
second by relying on S/L/T-submitted VOC or PM values via HAP augmentation. EPA may use other sources of
data, where available, including carrying forward previous-year data for gap filling. The database providing the
HAP augmentation factors is in the Emissions Inventory System Gateway. This database is updated based on
comments from the NATA reviews and may be further updated if new factors become available or if errors are
found. S/L/Ts should use their existing emission factors, or preferably source tests, prior to the submittal
deadline, and not rely on EPA's HAP augmentation dataset for inventory construction. The version of the HAP
augmentation database to be used for the 2023 NEI will be finalized by 1/15/2025. As with the 2020 NEI, S/L/T-
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reported chromium will be speciated into chromium (VI) and chromium (III) using chromium speciation factors
provided in the HAP augmentation database.
3.4.2 Nonpoint
One of the goals in developing the NEI is to have a eurythmic picture of the air pollutants in the nation for a
particular inventory year. To create this cohesiveness, EPA must treat data in a consistent way when emissions
data submitted by states looks significantly different in comparison to the rest of the data. Because EPA creates
estimates for many nonpoint sources, and thus has a rule of thumb for comparison purposes, we created a set
of business rules for EPA to determine what data to select for the final NEI.
For the 2023 NEI, we are using the following set of business rules, first adopted for the 2017 NEI.
Table 3-8: Nonpoint Inventory Business Rules
Item
If an agency submits...
EPA will...
Unless...
1
Emissions that exceed EPA
expected outlier check values
Use EPA estimates in lieu of
S/L/T data
State provides supporting material on
how the emissions were estimated,
including activity and emission factor
details where available
2
Pollutants not in expected
pollutant list
Remove these pollutants (e.g.,
VOC from road dust, metals
from evaporative processes)
S/L/T provides documentation on
these unexpected (surmised)
pollutants
3
VOCbut no HAPs
Run HAP augmentation off of
the S/L/T-submitted VOC
The VOC submitted falls outside of
EPA's expected outlier check
4
Total VOC-HAPs > VOC
(the sum of all of the HAPs
that are VOCs adds up to
more than the submitted
VOC value)
Remove all state submitted
VOC-HAP data and instead,
use HAP augmentation off of
the S/L/T VOC value
The VOC submitted falls outside of
EPA's expected outlier check
5
VOC and different VOC-HAPs
than our expected pollutant
list
Gap fill using HAPs generated
by HAP augmentation off the
S/L/T VOC value
The sum of VOC-HAPs adds up to
more than the VOC value; (see 4
above); in this case, all S/L/T HAPs will
be removed and replaced with HAP
augmentation off the S/L/T VOC value
6
An incomplete set of
expected criteria pollutants
Supplement using EPA tool
data for the pollutants that
are not submitted
S/L/T provides documentation to why
those emissions should not exist
7
VOC data for different SCCs,
but similar process
characteristics to what EPA
uses
EPA will augment VOC-HAPs
with similar profiles
State also submits HAPs with that VOC
For item 1, regarding emissions greater than outlier checks, the intention is to prevent inconsistencies when
looking at the nation as a whole and may be due to a mistake in calculations or data entry. EPA will initiate a
dialogue with reporting agencies where submitted emissions exceed expected ranges, particularly for rapidly
changing sectors, such as oil and gas. These outlier checks will be based on county-SCC-pollutant level statistical
analysis of the EPA estimates generated from the 2020 NEI. Supporting documentation requirements are not
intended to be onerous but can serve as a path for EPA to get confirmation that S/L/Ts intend for significantly
larger than expected emissions to be included in the NEI, may help inform EPA's tools, and can allow EPA to
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revise the outlier checks where needed. Outlier limits can be found by pollutant/SCC combinations in EIS under
Reporting Code Tables, Emission QA Values.
Item 2, regarding unexpected pollutants, is intended to prevent inconsistencies or incongruent data from
showing up in the inventory. Sometimes an agency submits pollutants that no other state agency reports, and
this may appear as an anomaly on the map for a particular pollutant when looking at a source category as a
whole. For example, one state agency reported lead as a pollutant from commercial cooking. While this may be
a real pollutant from the restaurant griddles, it also may be a mis-assigned SCC or pollutant code. In any case, if
EPA deems it an "unexpected pollutant," EPA may not have a good emission factor or may not have the data to
support that a certain pollutant is part of a source category. In these cases, when comparing the EPA dataset to
S/L/T datasets, a hotspot may show up, highlighting the submitting state, in this example, as the only place in
the country where you could find lead being emitted from restaurants.
Furthermore, S/L/Ts are usually discouraged from utilizing AP-42 emission factors (outside of the expected
pollutants for that source category) to estimate emissions for submission to the NEI. The exception to this rule
would be for those sources for which EPA does not provide estimates. The reasoning here is that the EPA
estimates (Wagon Wheel or otherwise) often include emission factors that are updated from those in AP-42, and
EPA ensures that these factors are consistent with the HAP augmentation factors in EIS. By letting EPA HAP
augmentation generate HAPs (based on S/L/T-submitted VOC or PM25-PRI emissions), we ensure complete and
consistent HAP coverage. The exception would be if you have improved emission factors for your estimates.
The expected pollutants list for all 2023 NEI EPA estimates will include HAPs and CAPs that EPA will gap fill if
these emissions data are not submitted by the S/L/T agencies. If EPA does not estimate emissions for a
particular source type, there will be no expected pollutants, but rather allowable pollutants, as EPA
acknowledges that those source categories that are not estimated on a national basis are not currently well-
assessed by EPA.
For the expected pollutants list, all pollutants for each nonpoint SCC are provided. We will map expected
pollutants to most active SCCs in sectors where EPA estimates exist for other like-process/fuel SCCs based on
data in the existing EIS HAP Augmentation table.
Item 3, regarding VOC submitted without their corresponding HAPs, is straightforward; the goal is to fill in
missing HAPs in the inventory where EPA expects them to exist, but they were not provided by the submitting
agency. HAP augmentation on S/L/T-submitted VOC will be used when it does not exceed the outlier check and
VOC is reported but VOC-HAPs are not. Item 1 would apply where the outlier check is violated.
Item 4, regarding VOC-HAPs summing to greater than VOC, is the broad check for where the sum of all S/L/T-
submitted VOC-HAPs must be less than S/L/T-submitted VOC. EPA is conducting this analysis to prevent
nonsensical data, since the parts should not add up to more than the whole. If a violation occurs, S/L/T-
submitted VOC is retained, but all S/L/T-submitted VOC-HAPs are not used (tagged out) and replaced with HAP
augmentation VOC-HAPs after scanning for obvious outliers.
Item 5, regarding different HAPs being reported than EPA's expected pollutants, builds off item 4 in complexity,
dealing with the messy scenario where we end up with a mix of S/L/T-reported VOC-HAPs and VOC-HAPs from
HAP augmentation. Like item 4, the intention is to prevent nonsense data where the parts sum up to more than
the whole. This happens when S/L/Ts submit VOC and some but not all expected VOC-HAPs, and HAP
augmentation, based on S/L/T-submitted VOC, is used to "gap fill" the remaining unreported VOC-HAPs. It is
understandable that S/L/Ts may only have emission factors for some VOC-HAPs and that the method may be
different from the VOC emission factor. However, air quality modeling based on the NEI assumes a level of VOC-
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HAP to VOC mass closure. Therefore, if S/L/Ts do not want EPA to generate "missing" VOC-HAPs, they should
submit emissions for VOC-HAPs that are in the expected pollutants list. S/L/T could submit zero emissions if
these pollutants are not emitted from these processes in a particular area due to controls, bans or other
location-specific information.
Item 6, regarding missing criteria pollutants, is intended to provide a cohesive inventory; for example, if NOx is
not submitted for a combustion category, EPA has the need to gap fill. This rule is simply a reflection of how the
NEI has been built in the past: S/L/T data takes precedence over EPA-submitted emissions. If EPA data exist for
pollutants that S/L/Ts do not submit, then EPA data "gap fills" and appears in the NEI selection. If S/L/Ts do not
want EPA data, that are in the expected pollutants list, to appear in the NEI, they have a couple options, ranked
in order of most to least preferred:
1. Ensure the Nonpoint survey response is "No, do not supplement my data."
2. Submit emissions, which could be zero if these pollutants are not emitted from these processes in
your jurisdiction for these "expected" pollutants, to ensure EPA emissions data do not appear in the
NEI, or,
3. Contact EPA to request removal (tag-out) of EPA emissions for these pollutants if they are not
emitted.
Option 1 is the "cleanest" automated option and avoids potential Option Set/Option Group issues that can cause
unintended removal of agency data in Option 2. Option 2 is a viable option when the zeros are for only some
pollutants. Option 1 is absolutely the best option when you want zero (or null) emissions for all pollutants for a
given SCC. This item is most important for CAPs and "high risk" HAPs. Option 3 was the standard approach prior
to the 2020 NEI; however, it should be a last resort as it complicates QA and has led to numerous errors in the
past.
Item 7, regarding running HAP augmentation on similar SCCs to those for which EPA has profiles, is also intended
to fill missing pollutants in the inventory, and this has been standard procedure in previous NEI cycles. Where
S/L/Ts report emissions for SCCs that EPA does not report, EPA data will be used if S/L/Ts do not report all
pollutants, and this goes beyond just HAP augmentation for VOC-HAPs.
Voluntary reporting for HAPs, particularly, VOC HAPs, gets complicated for some nonpoint sources where EPA
provides tools that include point source (inventory) emissions subtraction. For example, the Solvent tool only
subtracts point inventory CAPs for some sources, and not VOC HAPs, when choosing to subtract point emissions
and not activity data. The Solvent tool in this case will compute nonpoint VOC via point subtraction of emissions,
and then EPA will then use HAP augmentation in EIS to compute nonpoint VOC HAPs. The reason EPA built the
Solvent tool to not subtract VOC HAP point emissions is because the material balance for point subtraction
(reconciliation) is ideally based on activity/throughput of the material being balanced. Emissions, or emission
factors, from any source, have no validity in such a material balance. S/L/Ts are free to recompute their VOC
HAP emissions for nonpoint solvents, and so long as these VOC HAP emissions satisfy the checks discussed
above, they will be accepted.
None of these business rules impact what is stored in the EIS for each agency-only what will appear in the NEI
selection. EIS reports run off S/L/T datasets will still capture what S/L/Ts submit. However, as is standard
practice, the final inventory will reflect a converged set of data, with EPA tool data, S/L/T submitted data, and
augmentation datasets included.
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3.4.3 Mobile and Fires
Onroad and nonroad expected pollutants are the CAPs and HAPs generated by MOVES. For the state of California,
the EPA uses onroad emissions provided by California based on their emission factor (EMFAC) model.
The expected pollutants for the Fires sources are those that we estimate in EPA's methods. It is expected that
this list will remain the same as it was for the 2020 NEI. That list will be included in the nonpoint Expected
Pollutants List, to be located in the NEI SharePoint site's Resource Library before July 2024.
3.5 How should I make corrections if EPA or I find a mistake?
EPA inventory developers will work with S/L/T agency staff to provide feedback on their data and allow
corrections on a case-by-case basis. We recommend that S/L/T agencies first submit their corrections to the EIS
"QA Environment" and ensure they receive a clean feedback report prior to submitting corrections to the EIS
"Production Environment."
Make sure to submit the entire suite of pollutants for a point emission process or county-SCC combination!
Submitting only one pollutant erases the entire set of pollutants for that process or county-SCC.
On occasion, an S/L/T has submitted data in error and has the need to remove previously submitted emissions.
There are three methods for removing erroneously submitted data, with option 1 being the best and cleanest
option:
1. Use the Delete Reporting Period function in the bridge tool: Use the EIS Bridge Tool new component
"DeleteReportingPeriod" to remove all emissions, supplemental calculation parameters, and metadata
for a reporting period. Refer to the document "Changes to the Consolidated Emissions Reporting
Schema (CERS) for the 2020 National Emissions Inventory" on the EIS User's Manual page for more
details.
2. Submit zero emissions for a single pollutant: Submit zero emissions for any single pollutant at the
process. For nonpoint sources, this would be at the state-county FIPS, SCC (and shape ID if applicable)
level. You may additionally answer your NP survey to say "do not supplement" to prevent EPA backfilling
of this SCC, if that is what outcome you prefer.
i. Do not submit zero for a pollutant unless you know it is not emitted from a process. Also,
because of Option Set/Option Group reconciliation, it is important that if submitting zero for a
single pollutant, that this pollutant be "non-essential" and not used for any other SCCs in the
same Option Group.
ii. For point sources, this would be at the emissions process level. This method will ensure that
S/L/T emissions for this process are null. However, this method will not prevent EPA data from
potentially gapfilling missing S/L/T pollutants at this process. S/L/Ts can either submit zero
emissions for all expected pollutants or go with option 3.
3. Ask EPA to resolve: S/L/Ts contact EPA and request EPA "tag out" their submission (S/L/T tags). This
method requires information on specific processes and is less desirable because it relies strictly on email
transfer of information which has proven to be a resource drain during the NEI development cycle. In
addition, these S/L/T tags will not prevent EPA data from potentially gap-filling the resulting missing
S/L/T data unless S/L/Ts direct EPA to do so.
3.6 Why has EPA eliminated wholesale data replacements after the submittal due date?
EPA inventory developers do extensive QA on data received by the submission due date. Allowing wholesale
replacements, or initial submissions long past the original due date, causes EPA staff to run the complete QA
procedure on all data again. This process delays the NEI release, increases EPA's use of resources, and does not
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provide the benefit of the draft review and correction process described above. This change places a lot of
importance on the end of the submission grace period: January 15, 2025, for point, mobile and fires sources
and, as discussed in Section 7.6, March 31, 2025 for most nonpoint sources. It is very important that S/L/Ts meet
the submission deadlines with their best data in order that the QA review and correction process can proceed.
4 EIS Codes and Schema
This section examines planned EIS code and feature changes that are used in the NEI development.
4.1 EIS Reporting Codes and Schema Changes
EIS code tables that will be updated are listed below. We encourage inventory developers to download the
latest version of the reporting code tables directly from EIS. Any late changes to the code will be distributed to
S/L/T inventory developers every 2-4 weeks during the NEI development cycle via the existing NEI/NOMAD
SharePoint listservs. Contact Lindsay Dayton if you are not on this member list.
4.1.1 CERS Schema Changes
The CERS schema changes were fully implemented in EIS prior to the 2020 NEI in January 2021. Please refer to
the EIS User's Manual and HowTos Site document "Changes to the Consolidated Emissions Reporting Schema
(CERS) for the 2020 National Emissions Inventory" for more details on these changes.
4.1.2 Source Classification Code (SCC) Changes
EPA updates the list of active SCCs in collaboration with inventory developers and regulatory actions. EPA refers
S/L/T inventory developers to check the "Last Updated Date" on in the EIS Source Classification Code List, or the
publicly available EPA SCC Search site. Both sites are refreshed nightly. EPA will need to create new SCCs when
new inventory categories are developed and will retire SCCs for various reasons. These may include:
Technology is in the SCC list but is included in an SCC that is too broad, and the process in question is
unique, specific, and has a distinct emission factor and is being reported to other codes in an
inappropriate way. This indicates the need for a new code or codes and potentially retiring the broad
SCC.
Technology is obsolete and the code has not been used for reporting in one or more previous inventory
years. This indicates the need to retire the code.
The code may be redundant. Is there another code that is essentially the same? If so, which one should
be retired and why?
EPA will provide a list of active and proposed SCC changes as they become available. EPA will aim to lock in any
changes (e.g., retirements with "map to" SCCs) by December 2023 -at least 6 months prior to the S/L/T submittal
window opening in July 2024.
a. Point: There have been several changes to SCCs during and after the 2020 NEI development process;
several of these changes occurred after the release of the final 2020 NEI Plan.
b. Nonpoint: We plan to overhaul the residential wood combustion (RWC) sector, likely combining
freestanding and insert woodstoves and then disaggregating these, central heaters, and aesthetic
burning appliances to new SCCs based on the availability of emission factors. We also plan to generate
estimates for a few new source categories such as food trucks, residential cooking, and perhaps other
sources.
c. Fires: No new SCCs are expected. Starting with the 2020 NEI, there are no longer any "event" data category
SCCs for fires.
d. Onroad: No new SCCs are expected.
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e. Nonroad: No new SCCs are expected.
4.1.3 Pollutant Codes
While the above is the extent of known retired and additional codes, new codes for these and other EIS datasets
may be added later in the year if deemed necessary. No codes will be retired after the publication of this revised
plan.
The following pollutant codes have been added or modified since this the 2020 NEI was released in March 2023:
a. 18 Dioxins/Furan compounds, while active pollutant codes, have not been selected in the previous couple
of NEIs. We will resume including these compounds into the NEI for the 2023 selection. The EIS Pollutant
Category Name for these pollutants is changing from "Dioxins/Furans as 2,3,7,8-TCDD TEQs" to
"Dioxins/Furans (mass of congener, non TEQ)" to make clear that mass of each congener (rather than a
TEQ) should be reported.
b. New pollutant 106945, 1-Bromopropane, also known as n-propyl bromide, added prior to the 2020 NEI
cycle was assigned as a HAP on 1/5/2022.
c. Additional per- and polyfluoroalkyl substances (PFAS) compounds are being added in addition to the 180
PFAS compounds added prior to the 2020 NEI.
d. For the 2014 NEI, we added five PM2.5 species: EC (elemental or "black" carbon), OC (organic carbon),
N03 (nitrate), S04 (sulfate) and PMFINE (remaining or "crustal" PM) and two diesel PM species to the NEI
that are generated only by EPA through PM speciation. All of these pollutants will also be in the 2023 NEI,
but as with 2014 through 2020, they cannot be reported by S/L/Ts as they are generated by only EPA and
via EIS PM speciation.
e. Chromium trioxide (1333820) and Chromic Acid (7738945) have been retired. Users should use Chromium
III (16065831), Chromium VI (18540299) respectively, or total Chromium (7440473) if the valence is
unknown.
f. New pollutant Dibenzo[a,e]fluoranthene (5385751) added
4.2 Pollutant group business rules to prevent double counting of overlapping pollutants
EPA will again apply the business rules developed to allow different datasets in a selection to be blended
together while avoiding double-counting due to overlapping HAPs. There are several HAPs that belong to
pollutant groups or represent a pollutant group itself. Therefore, EPA has developed a set of business rules to
prevent both individual pollutants and a group of pollutants from different sources being in the inventory for the
same process or facility. For some pollutants, the rules apply both within an individual dataset (when SLT
submit) and to across datasets (when they are blended together); others apply only to cross-datasets. For
example, a rule that applies only to cross datasets is for PAHPOM code 250. This pollutant can be submitted with
other specific PAHs in an individual dataset but cannot be combined with any PAH across datasets. A rule that
applies to both within agency and cross agency datasets is PAH, total, code 130498292, this pollutant cannot be
reported at the same process with any individual PAH within a dataset. It also will not be selected across
datasets if it is from a lower priority dataset in the selection hierarchy.
A complete list of these business rules are provided in Appendix 1 "Business Rules: Selecting data with
overlapping pollutants across different datasets" on the 2023 NEI web site.
4.3 EIS QA Checks
1. A list of QA checks performed on data submittals can be found in the Emissions Inventory System
Gateway. There have been 283 new or updated EIS QA checks since the 2020 NEI Plan was released
in 2020. Filter on to the "Last Updated On" to find the most recently updated EIS QA Checks.
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2. We will be absorbing the Wagon Wheel Input Templates into EIS by July 2024. New QA validation
checks will be developed to ensure the proper formatting and allowable data are provided for
import. Additional QA warnings will likely be developed to provide tolerances for S/L/T-submitted
data versus the provided defaults.
5 EPA Data Completeness Feedback
5.1 EIS Data Completeness Reports
S/L/T agencies will be able to run data completeness reports using EIS at any time during the NEI cycle, and EPA
will send a reminder of these completeness reports about a month before the submittal window closes. For
point sources the Data Completeness and Outliers Report is refreshed each night and S/L/Ts can review or
download the report at any time. Allowing S/L/T agency staff to run these reports themselves will provide S/L/Ts
with the greatest possible time to address any incomplete findings in advance of EPA's notice (Section 5.3).
The completeness checks will be based on the following criteria:
Point:
1. All expected CAPs at all required facilities have been reported within expected ranges (i.e., no
outliers).
2. In addition to the above "Complete/Incomplete" designation, the percentage of expected CAPs and
the % of expected HAPs submitted within expected ranges is also provided in the report.
3. The on-line EIS Report shows any facilities with outliers, regardless of whether the pollutant is
expected or not.
Nonpoint:
1. Completion of a nonpoint survey. For more information on completing the nonpoint survey, see
Section 7.5.
2. If emissions were submitted by an agency, the number of missing Expected Criteria Pollutants. If an
agency does not submit emissions, and accepts EPA estimates via the nonpoint survey, this check is
omitted from the report.
Onroad/Nonroad:
Completeness is based on an agency either submitting inputs or accepting EPA estimates. EPA plans to develop a
list of key desirable MOVES inputs required by the AERR for each agency.
5.2 Nonpoint Iterative QA Reports
For the nonpoint data category, iterative QA reports will be sent out once a week to those S/L/Ts who have
submitted the previous week, during the submittal window opening (see Table 2-5). This iterative QA report will
be emailed out to the agency members designated as points of contact (or to receive notifications) for the
nonpoint data category in EIS. This report is intended to help the inventory submitter understand how EPA
determines completeness and assures quality emissions submissions to the nonpoint data category. The report
builds on any previous submissions and includes action items on how to correct identified issues, or whether
supporting documentation for their submissions is required.
Feedback included in the iterative reports will include:
1. Submissions dates
2. Number of sectors, SCCs submitted
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3. Nonpoint Survey Status (Goal: 100%)
(Note: Checks 4-7 are based on the Nonpoint Expected Pollutants List)
4. Missing Criteria Pollutants - two types of omission:
a. Complete Omission - pollutant is missing for all counties in an agency's jurisdiction for the
entire SCC
b. Partial Omission - pollutant is missing for at least one county in an agency's jurisdiction for a
SCC
5. Unexpected Criteria Pollutants
6. Unexpected Hazardous Pollutants (if HAPs were submitted)
7. Missing Hazardous Pollutants (if HAPs were submitted)
8. Zero Emissions
9. Review table by SCC/pollutant with a count of the number of counties submitted to the
pollutant/SCC combination vs the overall SCC.
New information in reports for 2023:
1. List of Input Templates submitted to EIS with a flag to indicate if the nonpoint survey answers
contradict this submission. There are two checks associated with this QA:
a. Did the S/L respond with "No" in the Nonpoint Survey, but also submit an input template?
Doing so would prevent the emissions generated in the Wagon Wheel, using the S/L input,
from being included in the NEI.
b. Did the S/L click the checkbox "Did your Agency Provide and Input Template for this
Category?" in the Nonpoint Survey and then fail to provide an input template?
2. Feedback/documentation already received from a S/L/T on previous submissions
5.3 Formal Completeness Letters
After the NEI submission deadline and grace period, EPA staff will compile summary reports combining the
findings from the EIS Data Completeness Reports and the Nonpoint Iterative QA Reports. Figure 5-1 provides an
example of the first page of the overall completeness report, showing a summary of completeness status for
each data category. The remaining pages in the completeness reports show the metric discussed in the previous
sections (5.1 and 5.2), with each agency receiving their own report.
Reports include both mandatory data as per the AERR as well as voluntary data such as submittal of activity
inputs for mobile and nonpoint sources. EPA will notify regional offices and state/local Air Directors as to the
status of the state/local submission. S/L agencies will only be able to see completeness reports for their own
agency and delegated agencies. The targeted dates for the Completeness Letters to Regional Offices and Air
Directors are also provided in Table 2-2 through Table 2-5, above. We will not be developing a formal
completeness report for Fires as their submittal is voluntary; however, we will include a thank you to those
agencies that submit timely and useful emissions, activity input data, and/or approval of EPA draft estimates.
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Figure 5-1: Example of First Page of Completeness Letter sent for 2020 NEI
Point:
Complete
Nonpoint:
Complete
Onroad:
Complete
Nonroad:
Complete
MEMORANDUM
Subject:
NEI 2020 Status Completeness Report
From:
Rich Mason
NEI Team Lead
Air Quality Assessment Division
Office of Ai r Quality, Planning & Standards
To:
EPA Regional Offices, Emissions Inventory Leads and State and Local Air Directors
Under the Air Emissions Reporting Requirements Rule, or AERR, 40 CFR part 51, states and local agencies are re-
quired to collect and submit emissions data to the EPA.
Data for the triennial inventory year 2020 were due by January 15, 2022 for point sources and by March 31,2022
for all other data categories. Agency staff were notified of their completeness status for point sources on April 20,
2022. For nonpoint sources, agencies were notified at Nonpoint Method Advisory (NOMAD) Workgroup calls as well
as upon submission to EIS of their completeness status, on an individual basis, through the Nonpoint Iterative QA
Summary Report. This memo serves as a status update of completeness for each data category according to the
parameters outlined below.
An addendum graphing each agency's status in regards to others in the region is also included.
Agency:| |
May 24,2022
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6 Point sources
6.1 Overview
Air agency point source data are the predominant source of point source data in the NEI. Point source reporting
includes both the "facility inventory" and "emissions" as separate submittal steps, each with their own set of
tables defined for electronic reporting. The following subsections provide a road map to the requirements from
the AERR, best practices for submitting data, and detailed information on point-source specific practices for the
2023 NEI, including a discussion on how EPA intends to include Greenhouse Gas (GHG) emissions for 2023 and
treatment of fugitive release point parameters in ElSfor modeling.
As in past NEI cycles, the EPA intends to augment state point source emissions when needed. These procedures
are explained in Section 3 of the 2020 NEI technical support document (TSD). There are two types of
augmentation: 1) using state-submitted emissions to estimate non-reported pollutants, and 2) using other
datasets to add emissions.
The first type of augmentation includes PM augmentation (e.g., estimating condensable PM if only primary is
reported), HAP augmentation (applying factors to ratio HAPs from state-reported CAPs) and chromium
speciation (estimating hexavalent chromium and trivalent chromium from state-reported unspeciated
chromium). HAP augmentation profiles may be updated during the 2023 cycle. More specifically, EPA will work
on adding more profiles based on the SPECIATE database as an additional source of HAP to CAP ratios. Any S/L/T
data that does not meet the submittal deadline may not be augmented and therefore may end up incomplete in
the NEI.
The second type of augmentation includes the use of data from the TRI (also explained in the 2020 NEI TSD, and
Section 6.4 in this document for more details). There may also be situations where we use other EPA datasets
such as data developed from an information collection request for regulatory efforts. These may be used ahead
of state emissions or for gap filling where these data are collected.
6.2 Inclusion of Greenhouse Gas Emissions for Point Sources
EIS has included an emissions data set containing the point source GHG (C02, CH4, N20 and SF6) emissions as
reported by facilities to the EPA GHG Reporting Program (GHGRP) beginning with the 2013 emission year. These
GHGRP emissions were not included in the 2014 NEI but were included for the 2017 NEI and 2020 NEI for those
four GHGs in the published NEI. We plan to do the same for the 2023 NEI. The primary source of the selected
GHG data will be the direct facility reporting to the GHGRP. We will also use S/L/T reports of the same four GHGs
if they have been reported for facilities which do not appear in the 2023 GHGRP data. We expect that any such
S/L/T reports which are so used will be for smaller emitters of GHGs, given the reporting requirements of the
GHGRP. We will use the GHGRP data preferentially over S/L/T-reported data because the GHGRP data is
required of the facilities, the calculation procedures have been prescribed by regulation, and the facility-
reported data is reviewed by the EPA GHGRP to be EPA's authoritative source of GHG emissions for those
facilities. Note that we are not requiring S/L/Ts to report GHGs to EIS for any facilities, but we plan to include
any voluntarily reported S/L/T point source data in the NEI if it appears to be valid and if we do not have any
GHGRP data for that facility.
For 2023 we plan to use the facility-level totals for each of the four GHGs from the EPA GHGRP. We will also
store in EIS and use in the NEI the facility-level biogenic C02 emissions as reported to the GHGRP. Biogenic C02
is reported as a separate element to the GHGRP. As with the earlier years, we will convert the values as
published on the GHG Reporting Program Data Sets website from C02-equivalent (C02e) mass to actual mass,
for consistency with the rest of the NEI and its applications. The conversion factors used for the 2017 and 2020
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May 31, 2023
NEIs will be used again for the 2023 NEI. These were obtained from Table 1 of the IPCC's Fourth Assessment
Report (25 for methane, 298 for nitrous oxide, 22,800 for sulfur hexafluoride), per the documentation given on
the GHG Reporting Program web page.
A crosswalk of which GHG facility IDs correspond to which EIS Facility IDs for the purposes of writing the GHGRP
emissions values into EIS is available in EIS. The GHGRP facility IDs are stored as Alternate Facility IDs for each EIS
facility. These Alternate Facility IDs can be seen on the EIS Gateway screens for a particular facility, or a bulk
report can be obtained from EIS by using the Facility Configuration reports, Alternate Facility IDs, and filtering
for Program System Code = "EPAGHG". In some cases, more than one GHG facility was matched to a single EIS
facility ID. In those cases, the sum of the multiple GHG facilities will be written to the EIS facility. Based on the
2021 reporting year, 95 percent of the total C02 reported to the GHGRP is matched and stored to an EIS facility.
6.3 Release Point characterization
With the new schema discussed in Section 4.1, there are additional options to represent stack and fugitive
release points. In addition to the current approach of the circular stack, we added the ability for a rectangular
release. Fugitives can now be characterized in several ways, including the current length and width option, a
new end points option and a volumetric option. These approaches are detailed in the schema document.
6.4 Quality Assurance of TRI vs SLT-submitted data
EPA standard practice is as a starting point, to select S/L/T-submitted HAP data over TRI data, regardless of the
completeness of the S/L/T HAPs submitted. To compile as complete a HAP inventory as possible, EPA has
manually selected TRI data to supplement and/or replace S/L/T-submitted HAP emissions in previous NEI cycles
to remedy the most obvious deficiencies in S/L/T-submitted HAP data. For the 2023 NEI, EPA will again analyze
TRI vs S/L/T HAP data, and if possible, establish a more automated process for supplementing and/or replacing
S/L/T-submitted HAP data.
EPA will load into EIS the 2023 TRI data when it is released publicly in the Fall of 2024. S/L/Ts can run EIS
comparison reports against their S/L/T-submitted HAP data to review for large differences between the two
datasets and reconcile them prior to the final submittal deadline, if possible. If States do not think that their
inventory process accounts for all significant sources of a HAP for a facility, they should not report that HAP for
the facility; i.e., do not allow auto-calculations to create records for just the processes and SCCs that happen to
be in your auto-calculate file. States should also not report TRI facility-level data as their own, because the EPA
process will bring in that TRI data and maintain its source identity.
6.5 State total fuel consumption throughput needed
The AERR has a requirement for submitting activity data (throughput) information of point sources. This
throughput is necessary to reconcile industrial (I) and commercial/institutional (C/l) fuel combustion in the
nonpoint data category. If S/L/Ts do not provide point throughput by fuel type (e.g., natural gas, distillate oil,
coal) and sector (I versus C/l), then EPA will seek to obtain point throughput (and a valid Calculation Parameter
Unit of Measure Code) by fuel type, and 2-digit aggregated NAICS code which will be used to assign the I vs C/l
sector. More information on this request is in Section 7.7.
7 Nonpoint sources
7.1 Overview
Air agency nonpoint source data is an increasingly significant contributor in the NEI, particularly for those
nonpoint categories that have overlap with point sources. Nonpoint sources include (but are not limited to) fuel
combustion categories; oil and gas production; industrial, commercial and consumer solvents; residential wood
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May 31, 2023
combustion; road and construction dust; and agricultural emissions sources. Most of these sources are covered
by an emissions estimation tool called the Wagon Wheel.
It should also be noted that the Wagon Wheel does not generate emissions for every nonpoint source that EPA
estimates. EPA has a separate Oil and Gas tool, and provides estimates for commercial marine vessels,
locomotives, agricultural field burning, portable fuel containers, ag livestock waste emissions, ag fertilizer
emissions and biogenics. Starting with the 2020 NEI, and continuing for the 2023, wildfires and prescribed
burning emissions are provided in the nonpoint data category. However, the data collection and development
steps for wildland fires are unique and discussed separately in Section 9 of this plan.
As in past NEI cycles, the EPA intends to augment state nonpoint source emissions when needed. The nonpoint
tools that EPA develop also serve a secondary purpose: to provide fallback data for the EPA to use where S/L/Ts
do not submit adequate data to the inventory. Further, augmentation of S/L/T data also includes PM
augmentation, HAP augmentation (factors to ratio HAPs from CAPs), and chromium speciation.
The nonpoint data category has the most complicated set of data sources. Therefore, we plan to continue to use
the EIS feature called Option Group/Option Set (see Appendix 6 in the 2017 NEI Plan) and business rules for
cross-dataset pollutant selection (Appendix 1). These two EIS functions help eliminate double-counting and
automates the process of selecting data based on overlapping SCCs.
We anticipate limited resources for revising methods for existing tools for the 2023 NEI. Therefore, with a couple
of notable exceptions, the 2020 NEI TSD will be a fairly complete and useful starting point for understanding
how the existing EPA nonpoint tools were developed. The primary focus will be on updating activity data into
input templates for the 2023 NEI, and more importantly, migrating the input templates into EIS. States and
Locals will still have the ability to import CSV input templates into the Wagon Wheel -a function introduced for
the 2020 NEI- and create draft emissions for comparison. We still strongly suggest that S/L/Ts submit input
templates where possible.
7.2 New Methodologies
Any new nonpoint modules will be accompanied by new NEMOs (Nonpoint Emissions Methodology and
Operating instructions) and input templates. New methodologies can encompass many things for a given sector:
introducing emissions with new methods for the first time, improving current methods, improving the EFs
associated with the process, improving the activity data associated with the process, and updating speciation
which could result in improved/revised HAP estimates. The proposed new methodologies for estimating
nonpoint emissions include:
Abandoned oil and gas wells
Commercial (existing but needs upgrade) and residential cooking, and food trucks
Roofing asphalts
Structure fires
Motor vehicle fires
Stage 1 gas distribution
Residential wood combustion, including campfires
Including agricultural livestock waste into the wagon wheel
Switching from the Fire Emission Production Simulator (FEPS) database for WLF EFs to Smoke Emissions
Repository Application (SERA) in the emissions modeling process
Inclusion of Wildland Urban Interface (WUI) fires, likely will only effect CA if they occur in 2023
Adding dioxin/furan estimates for as many sources as data allow
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May 31, 2023
Splitting agricultural fertilizer emissions into an anthropogenic component and a biogenic component in
EPA's estimates
EPA plans to have these new/revised methodologies completed for S/L/T review before the submission window
opens in July 2024.
7.3 The Wagon Wheel Tool
We will again utilize the Wagon Wheel central database to house all inputs and calculate emissions for most
nonpoint source categories. The Wagon Wheel Tool is a nonpoint emissions estimation tool for most EPA
estimates for this data category. An S/L/T can update existing default activity data to create local level emission
data with EPA methods and factors. The Wagon Wheel tool, illustrated in Figure 7-1, will undergo minimal
updates for this NEI cycle.
Figure 7-1: EPA Wagon Wheel and some of the associated modules used to generate nonpoint estimates
AvGas
Compost
Ag
Tilling
Ag
Pesticides
Construction
Dust and
Open
Burning
\
Master Database
Activity data (e.g.
SEDS, County
Business Patterns,
Population)
Emission factors
General tables
(FIPS codes, pollutant
codes, SCCs)
Point source data
Crosswalks
Interface
Mining and
Quarrying
Residential
Grilling
Residential
Heating
Table 7-1 provides the estimated deliverable date for each wagon wheel category based on last-available activity
data. For S/L/T inventory developers, we will provide wagon wheel releases in three "natural breaks" batches
that can be used to compare final default activity data with your own activity data. See the activity data tracker
on the NOMAD SharePoint site for the latest information. Note that it is often uncertain when activity data will
be available for some tools. Wagon wheel default input data will remain year 2020 until it is refreshed prior to
the first release in July of 2024 with primarily year 2022 data for some activity data such as County Business
Patterns and SEDS. A limited set of activity data will be updated to year 2023 prior to the first wagon wheel
release -likely limited to landfills, commercial cooking, and publicly owned treatment works. Year 2020 or year
2022 activity data will continue to be used until year 2023 activity data is available, reflected in Table 7-1. A final
wagon wheel, version 4, will absorb ali quality-assured S/L/T input template data submitted to EIS.
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May 31, 2023
Table 7-1: Estimated deliverable for each wagon wheel category based on last-available activity data
Tool
Month
Year
Limiting data
Publicly Owned Treatment Works (also in pt)
March
2024
Population*
Landfills
April
2024
EPA LMOP Database
Commercial Cooking
July
2024
Hoovers restaurant data
Wagon Wheel Release 1 July 31, 2024
Agricultural Tilling
August
2024
USD A Ag Survey
Dust from Hooves
September
2024
GHG Inventory Livestock Counts
Agricultural Livestock Waste
September
2024
GHG Inventory Livestock Counts
Agricultural Silage
September
2024
GHG Inventory Livestock Counts
Wagon Wheel Release 2 January 31, 2025
Composting
April
2025
County Business Patterns
Other Mercury
April
2025
County Business Patterns
Construction Dust
May
2025
FHWA Highway Statistics
Open Burning
May
2025
FHWA Highway Statistics
Aviation Gasoline
June
2025
SEDS
Residential Heating
June
2025
SEDS
Industrial/Commercial/lnst. Fuel Combustion
(also in Point)
June
2025
SEDS
Residential Wood Combustion
June
2025
SEDS
Residential Grilling
June
2025
American Housing Survey Housing
Estimates
Asphalt Paving
June
2025
MOVES VMT
Road Dust
June
2025
MOVES VMT
Stage 1 Gasoline Distribution
June
2025
MOVES C02 Emissions,
MOVES Benzene Emissions
Solvents (also in Point)
June
2025
MOVES VMT
Wagon Wheel Release 3 July 31, 2025
Agricultural Pesticides (in Solvents Tool)
Unknown
2025
USGS County Pesticide Use
Cremation
Unknown
2025
CDC WONDER Database
Mining and Quarrying
Unknown
2025
USGS Minerals Yearbook
Wagon Wheel Release 4 Unknown, dependent on lagging data releases
* Assumes that new Clean Water Needs Survey data will not be released, and we will continue to grow 2012
data
EPA is encouraging states and locals to provide inputs to the Wagon Wheel Tool (see next section). This prevents
rework on the S/L/T's part if there is an update to the Wagon Wheel tool. By having one tool that EPA uses, we
hope to eliminate errors in a cohesive way, and ensure that the data is consistently calculated by all data
submitters.
7.4 Input Templates into EIS
New for the 2023 NEI development cycle is an improvement to the process for submitting input templates for
the Wagon Wheel. Input templates are a series of activity data within given sector categories that are collected
from S/L/Ts, to be used in lieu of provided default activity data, as inputs to the calculations of the Wagon
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May 31, 2023
Wheel. These input templates for the most part represent "activity," and will create the baseline numbers
which, in combination with EPA nationally recognized emission factors, will create the 2023EPA_NONPOINT
dataset. In the past, agencies have varied in their use of these nearly 100 available templates. There were states
who submitted no templates, but most averaged around 6 or 8 templates, while a small handful submitted
several dozen.
Input templates will be collected in the Emissions Inventory System (EIS). Benefits include:
These activity data will be available in EIS along with the final emissions.
An S/L/T will be able to run a report in EIS to download previous activity year data, or view other S/L
datasets, for comparison.
A batch of a complete inventory cycle year's input template data can be retrieved by EPA staff or
contractors for input into the Wagon Wheel.
Data can be validated within EIS.
This is one additional step towards absorbing the entire Wagon Wheel in EIS.
Each S/L agency will only be able to submit input templates for their own agency jurisdiction. For example, in the
State of Tennessee, there are multiple jurisdictions. Several metropolitan areas such as Shelby County, Knox
County, and the Chattanooga and Nashville metropolitan area report their emissions, and the Tennessee state
agency reports the rest of Tennessee. When creating input templates, only the counties associated with the
jurisdiction under which those emissions fall will be available for input submissions.
Furthermore, only one option for the Industrial/Commercial and Institutional Fuel Combustion (ICI) will be
allowed: point inventory fuel consumption by sector and fuel. Previously this option was referred to as "option
C." Option A and B ICI input templates are simply more-granular (NAICS/SCC and NAICS respectively); agencies
that generated inputs at this resolution simply need to aggregate to sector/fuel to convert these to Option C.
We are discontinuing the ability to provide Option D (nonpoint fuel consumption) as there are several
adjustment assumptions that are lost in translation when we receive only Option D inputs -for example, the
fraction of fuel consumed by nonroad mobile sources and the fraction of fuel used by industrial processes where
it is not combusted (e.g., chemical feedstocks, lubricants, solvents).
A mockup screenshot of what the Input Template homepage and selected tool detailed view page might look
like in EIS are included in Figure 7-2 and Figure 7-3, respectively. Note that these are draft and are likely to
change.
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May 31, 2023
Figure 7-2: State/Local Nonpoint Input Templates Homepage in EIS
Agency Organization Detail
Current Agency
Agency Description:
Agency Type:
ETL Process Group;
Alabama Department of Environmental Management
Stats
AgaHf Responstottles
Marfcers Program Sysaem Codes
Feedback Report NcrPaMrl Survey W^yin \iVhed Ternpbres
Select a Wagon Wheel Tool to Review Information
~ Agricultural Silage
~ ICI
~ Agricultural Tilling
~ Landfills
~ Asphalt Paving
~ Mining and Quarrying
~ Aviation Gasoline
~ Other Mercury
~ Central Database
~ POTW
~ Commercial Cooking
~ Residential Grilling
~ Compost
~ Residential Heating
~ Construction Dust and Open Burning
~ Road Dust
~ County Business Patterns
~ RWC
~ Cremation
~ Solvents
~ Dust from Hooves
~ Stage 1 Gasoline Distribution
1 mport Templates
Export All Templates
Option Greyed out
u»Ttil at Least One
Box Selected
Figure 7-3: State/Local Nonpoint Input Template Detail for Selected WW Tool
Agency Organization Detail
Current Agency
Agency Description:
Agency Type:
ETL Process Group:
Alabama Department of Environmental Management
State
Agency RrjpanstoHlei
Agricultural Tilling
Agency-Level Factors
Agency Mefrtoere FYcgram Syslem Codes
feedback Report NoTpcirrt Sj"vey Wagpfi Wheel Templates
Export Template
GroupLevel
GroupVtMue
VaJueSetTvpe
DefauttValu Newvalue
Notes
Source
SourceYear -
5
Daialtem
AG LAND. CROPLAND, (EXCL HARVESTED & PASTURED} - ACRES
Acres
8816
USD A 2017 Cen
2017
Daialtem
ACRES
Acres
668
U5DA 2017 Cen
2017
Dataltem
AG LAND, PASTUREIANO, (EXCL CROPIAND & WOODLAND) - ACRE5
Acres
23255
U5DA 2017 Cen
2017
Dataltem
AG LAND, CROPLAND, (EXCL HARVESTED & PASTURED)
Acres
461766
U5DA 2017 Cen
2017
Dataltem
AG LAND, CROPLAND. (EXCL HARVESTED & PASTURED), CULTIVATED SUMMER FALLOW
Acres
65396
U50A 2017 Cen
2017
Dataltem
AG LAND. PASTURELAND, (KCLCROPlANO & WOOtXAND)
Acres
2132820
USOA 2017 Cen
2017
Dataltem
BARLEY
Acres
89-66666667
USOA 2017 Cen
2017
V
County-Level Factors
CountyNarne
GroupVatue - ValueSetType
- DefaultValu - NewValue -
Notes
Source
SourceYear -
Autauga
Control Factor
0
Autauga
AG LAND, CROPLAND, (EXCL MARVE5" Acres
SS16
USDA 2017 Ceo
2017
_
Autauga
ACRES Acres
668
USDA 2017 Cen
2017
Autauga
AG LAND. PASTURELAND, (EXCLCROF Acres
232S5
USDA 2017 Cen
2017
Autauga
BARLEY Acres
89.66666667
USDA 2017 Cen
2017
Autauga
CANOLA Acres
0
USDA 2020 Cen
2020
Autauga
CORN Acres
1030
USDA 2017 Cen
2017
7
Input Template Loading Ability
For the 2020 NEI, EPA developed a tool to enable S/Ls to load and run the Wagon Wheel with their inputs to test
the tools. We strongly encourage S/Ls to submit their input activity data and not their own emissions from
running the Wagon Wheel. This feature was developed as a QA tool and not a method for generating emissions
for submission to EPA.
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7.5 Nonpoint Survey
Because each agency has their own universe of sources and inventory development approaches, each agency
reports nonpoint estimates a little differently. The nonpoint survey gathers information specifically for each S/L
regarding which source categories are covered by their point or nonpoint emissions submittals (or both), or if
there should be no nonpoint emissions for a particular source category.
This survey asks only two questions:
1) Have you provided an input template for this set of SCCs?
2) Should EPA supplement the S/L emissions submission or not?
Refer to Section 5.2 to understand how Nonpoint Survey responses will be quality-assured against S/L inputs
submitted (or not). The second question can be answered at the level of the entire nonpoint data category, for
all SCCs in a particular EPA tool/database, or an SCC-by-SCC basis. The reasons for not supplementing S/L data
with EPA data would be:
S/L does not have this type of source (i.e., no coal fired residential boilers),
S/L completely covers this category in their point submittal (i.e., gas stations are all covered in point in
the state of Colorado), or
S/L uses a different SCC that covers the same process covered by the SCC used by EPA that also covers
additional processes (e.g., composting under SCC 2680002000 where this SCC covers both green waste,
which EPA methods cover, as well as other materials being composted).
In addition, there is a 4th option "Supplement only at reported location -SCCs" where EPA data will only
supplement pollutants where S/L reported some but not all expected pollutants at a given county and SCC but
will not supplement with EPA data where S/Ls reported no data (pollutants).
The nonpoint survey has been in use for several inventory cycles, and we do not anticipate any major changes
for the 2023 cycle. Please see the AirKnowledge training on filling out the nonpoint survey if you have questions.
7.6 Nonpoint Submittal Deadlines equiremeiits
One of the biggest challenges with the nonpoint data category has been managing the release of the "final" EPA
estimates (and tools). EPA relies on a varied set of input data (see Table 7-1). The timeline relies on the release
of activity data for the Wagon Wheel tool. Submittal deadlines depend on the whether the sources are in the
Wagon Wheel tool or not.
7.6.1 Milestones and deadlines for WW sectors
There are three planned releases of the Wagon Wheel during the 2023 NEI development cycle. The first covers
the three tools: POTWs, landfills, and commercial cooking, and is expected to be released on 7/31/2024. The
second covers ag tilling, ag silage, and dust from hooves, and is expected to be released 1/31/2025. And the
third covers the rest of the tools, and is the most tentative of the dates, but it is expected to be released on
7/31/2025. EPA is also planning for a fourth Wagon Wheel release at a date to be determined that includes all
S/L-submitted inputs and any potential late tweaks in the tool or activity data.
The AERR date for submittal is typically January 15, 2025. For the tools in the first Wagon Wheel release, and
any sources that EPA does not estimate, the submittal deadline is March 31, 2025. For the tools in the second
and third wagon wheel releases, S/L/Ts have 30 days after the release to provide input templates, and 60 days
to provide emissions and documentation. Refer to the schedule in Table 2-5 for more specific dates.
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Requiring documentation for emissions estimated differently from the EPA nonpoint methodologies is crucial for
EPA to understand and justify accepting an S/L/T's emissions estimates, especially when S/L/T estimates differ
significantly from EPA estimates.
EPA plans to upload the latest-available activity data to the Wagon Wheel if it becomes available prior to
"locking" in the final Wagon Wheel estimates later in the summer of 2025. Therefore, we strongly suggest
submitting your own activity data inputs and/or selecting "Yes -Supplement my data with EPA Estimates" in the
Nonpoint Survey if you want to ensure that the most-recently available default activity data are used in the 2023
NEI. In some cases, S/L/Ts may have earlier access to more local data and if they submit their own activity data,
can ensure that the 2023 NEI and Wagon Wheel are based on "EPA" data that include the most-current local
activity data.
We encourage S/Ls who choose to run the Wagon Wheel themselves to send EPA activity data and accept EPA
estimates; this way, if EPA finds systemic issues with the tools, they can be updated as a whole. Basically, if you
generate acceptable estimates with the Wagon Wheel prior to March 31, 2025, we strongly prefer that you
submit your inputs, not emissions, to SharePoint (EPA), and indicate "Yes - Supplement my data with EPA
Estimates" in the Nonpoint Survey.
7.6.2 Milestones and deadline for non-WW sectors
A list of all EPA estimates not generated via the Wagon Wheel is provided in Table 7-2.
Table 7-2: EPA estimates not generated from the Wagon Wheel
Nonpoint Tools/Estimates
EPA Tool or Stand-
alone Database?
Point Inventory
Subtraction?
Ag Fertilizer
database
No
Agricultural burning (cropland residue
burning)
database
No
Wildland fires (wildfires and prescribed
burning)
database
No
Biogenics
database
No
Portable Fuel Containers (PFCs)
database
No
Oil and Gas Production & Exploration
Tool
Yes
Commercial Marine Vessels (CMV)
database
No
Rail (locomotive)
database
No
In-flight Lead
Tool
No
While the schedule for these nonpoint categories will generally follow the outline shown above for releases of
data to the public and on the requirements for completeness reports, there are some differences as highlighted
below in Table 7-2 for agricultural fertilizer application and agricultural livestock waste sectors. The methods for
each of these agriculture categories will be like those used in the 2020 NEI. As such, any tweaks we make to the
methods will be highlighted in our draft documentation via NOMAD calls. No extensive revisions to these
methodologies are planned for the 2023 NEI. We discuss CMV in Section 8.4, and fires in Section 9.
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Table 7-3: Schedule for Agricultural Fertilizer Application and Ag Field Burning
Item description
EPA
or
S/L/T
Date
Comments
Review SCCs, suggest clean-ups and
additions either via 2023 NEI plan, or via
SharePoint site once analyses completed
EPA
8/1/2023
Might be done via NOMAD call or via group
Review methods, develop tweaks based
on 2020 NEI comments, and other
updates that have become available
EPA
10/1/2023
No major revisions are expected for these
categories. The ag burning method is in the
published literature, Ag fertilizer methods
soon will be. The methods are expected to
be nearly identical to what was used in 2020
NEI. NOMAD calls will be used to correspond
on any tweaks made to methods
Develop draft emission estimates
EPA
5/1/2024
Post these estimates on SharePoint. Include
draft documentation and any requisite
summary files.
Comment process on draft emissions
S/L/T
5/1/2024-
8/1/2024
This would include the S/L/Ts looking at
emissions, looking at activity data. After
reviewing our estimates, letting EPA know if
they accept our estimates, have comments,
or would like to submit activity data on any
of the sectors (acres burned for ag burning,
and fertilizer use patterns for ag fertilizer)
Submission window opens in EIS
S/L/T
6/1/2024
Submission window opens for any S/L/Ts
that would like to submit emissions for these
sectors
Submission of alternative activity data
S/L
9/1/2024
The submitting agency should work with EPA
to determine formats for submitting any
activity data for any of these sectors
Submission window closes for these
nonpoint sectors in EIS
S/L/T
3/31/2025
QA of all S/L/T data and responses back
to S/L/Ts
EPA
6/1/2025
EPA provides comments on all submitted
emissions data by S/L/Ts
EPA works with submitted comments,
any additionally submitted activity data,
and other clean up that is required to
develop final EPA emissions
EPA
8/1/2025
By May 2025, EPA will address all the
comments, include any new activity data (as
possible/feasible) and re-post "final"
emission estimates.
Make decisions on which S/L/T data to
tag out based on EPA QA of S/L/T
submitted data
EPA
9/30/2025
Inform S/L/Ts of any of their data we will
need to tag out, not include or otherwise
not be able to use.
Final QA of S/L/T and EPA data to check
for errors
EPA
12/30/2025
Finalize all these sectors in EIS
EPA
2/28/2026
Public release of all these sectors, along
with all of nonpoint
EPA
3/31/2026
Includes query tools, documentation,
summary files
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7.7 ICI Tool Requirement; Agency total fuel consumption throughput needed
EPA, in collaboration with the ICI NOMAD team (contact Rich Mason for more information) developed the input
templates used for the nonpoint ICI component of the Wagon Wheel. For the 2023 NEI, the Energy Information
Agency (EIA) State Energy Data System (SEDS) state-level fuel consumption data will again be used as the
starting point for computing nonpoint throughput, split out for Industrial vs Commercial/Institutional facilities.
As mentioned in Section 3.2.2, the AERR has a requirement for submitting activity data (throughput) information
of point sources. Because nonpoint estimates are created using total fuel consumption by state (technically
agency-level), this throughput is necessary to reconcile industrial (I) and commercial/institutional (C/l) fuel
combustion in the nonpoint data category. If S/Ls do not submit ICI nonpoint emissions, then EPA requests that
S/Ls provide agency-total point throughput by fuel type (e.g., natural gas, distillate oil, coal) and sector (I versus
C/l).
When providing this point fuel consumption data, S/Ls should first quality assure their data by comparing their
agency-total point fuel consumption versus the total SEDS fuel consumption for each sector and fuel type. Point
throughput data should not exceed SEDS fuel consumption.
Conversely, if point fuel consumption data is a tiny fraction of SEDS data, then they should review units of
measure and completeness of the point inventory fuel consumption data; this is particularly true for industrial
sector fuels, where it would be expected that a significant component of total fuel consumption would be
reported as Type A or Type B point sources. Otherwise, the nonpoint contribution to ICI emissions will be too
large (double counted with point inventory).
7.7.1 A non-ideal default approach for computing point inventory fuel consumption
Unchanged for the 2023 NEI, EPA will subtract fuel-specific S/L-submitted state-level I vs C/l throughput from
the EIA consumption data to estimate the nonpoint I vs C/l throughput by fuel type. S/Ls are strongly
encouraged to engage in this process as a lack of submitted point throughput data (or emissions submittal)
forces EPA to implement the "default" method for estimating nonpoint emissions as computed from total SEDS
activity data.
For the 2020 NEI, EPA developed this "default" method to ensure point inventory (fuel consumption)
subtraction and therefore less potential double-counting of ICI emissions in nonpoint with those in the point
inventory. This new default approach is based on S/L-submitted point inventory carbon monoxide (CO)
emissions relative to S/L-submitted point CO emissions vs point fuel consumption ratios -for those S/Ls that
submitted point fuel consumption data. This is not intended to be used by most S/Ls and is truly a "last resort"
option for EPA. A critical number of quality-assured point inventory fuel consumption input template data
submittals are needed for this approach to make sense as the composition of industries and point inventory
submittals varies significantly across S/Ls.
Not submitting S/L emissions or input template (point fuel consumption) data will indicate to EPA that you are
fine with EPA's default method being used.
7.8 Utilization of E ion Group/Option Set evaluation to compile NEI
The EIS has an Option Group/Option Set (OG/OS) feature that was first implemented for the 2017 nonpoint NEI.
In the Source Classification Code table, we define SCCs that have a hierarchical nature. That is, there may be a
"general" group, as well as more specific SCCs within the same group. These relationships are defined by the
"Option Group / Option Set" (OGOS) fields in the SCC table. When EPA and S/L/T datasets are placed in an NEI
selection, there is the potential for double counting of data sources (emissions) across these data sources. For
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example, the EPA may report emissions to a "general" SCC while S/L/Ts report data to detailed SCCs. Without
OGOS evaluation, both sets of data would be included in the NEI selection.
The current OGOS rules employed in the selection assumes that if a S/L/T submits data, they are submitting data
for the entire group and no additional data sets are to be used to "backfill" any SCCs within the same option set.
The desired function is for the selection to backfill any SCCs within the same option set. Refer to "Appendix 6 -
Option Group Option Set Enhancement EIS Requirements.pdf" on the 2017 National Emissions Inventory Plan
website for a comprehensive discussion on the OGOS business rules first implemented in EIS for the 2017
nonpoint NEI, that will be retained for the 2023 NEI.
8 h >i. sources
8.1 Overview
Mobile sources are sources of pollution caused by vehicles transporting goods or people (e.g., highway vehicles,
aircraft, rail, and marine vessels) and other nonroad engines and equipment, such as lawn and garden
equipment, construction equipment, engines used in recreational activities, and portable industrial, commercial,
and agricultural engines.
The EPA creates a comprehensive set of mobile source emissions data for criteria, hazardous air pollutants, and
greenhouse gasses for all states, Puerto Rico, and U.S. Virgin Islands as a starting point of the NEI. The EPA uses
models to estimate emissions for most of the mobile source categories. With the exception of California and
Tribes, the EPA requires S/L/T agencies to submit MOVES model inputs where applicable, rather than emissions,
so that the EPA can use those inputs if MOVES is updated and for consistent future year mobile source
projections.
8.2 Oeroad approach for 2023
The EPA will continue to use MOVES for the 2023 NEI for both onroad and nonroad emissions, the exact version
will be determined prior to the submittal window opening in June 2024.
Collection of inputs, rather than emissions, is required to provide EPA the ability to run varying model scenarios
and future projections from the same input basis. Model input data collection will be like the process used for
the 2020 NEI. The EPA is interested in comments on the current MOVES input process in planning improvements
for the 2023 NEI cycle.
8.3 Nonroad approach fo
Same as the 2020 inventory cycle, only MOVES input format (CDB) will be accepted. The 2023 NEI will use the
same SCCs for mobile sources as used in the 2020 NEI.
8.4 Commercial marine vessels approach fo
EPA plans to again use Automatic Identification System (AIS) data points from the US Coast Guard to identify
ships and their activity. Unless an agency has similar, or more granular AlS-based emissions, it is unlikely they
will have superior emissions estimates. S/L/Ts are encouraged to review the 2020 methodology and accept EPA
CMV data for 2023. Although EPA will generate hour-specific files for modeling, the data stored in the EIS/NEI
will be annual. NEI port emission will be in shape files, underway in county files.
8.5 Rail approach for 2023
For the 2023 inventory cycle, line-haul rail emissions will be at the county level. Rail yards will still be at the
facility-level. EPA will be using rail estimates developed via the Eastern Research Technical Advisory Committee
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(ERTAC) as was done for 2020. S/L/Ts are encouraged to be involved in this process and may choose to accept
this data in lieu of submitting.
8.6 Aircraft approach for
For the 2023 inventory cycle, we are using the same methodology as used for the 2020 NEI. We will collect
landing and take-off inputs, which S/L/Ts will be asked to review/update. Then EPA will run the Federal Aviation
Administration's model to estimate emissions. For the 2023 NEI, we will use the Aviation Environmental Design
Tool (AEDT) for EPA estimates. There may be a version update provided by FAA.
9 Fires
9.1 Overview
The AERR does not require S/L/T agencies to report emissions from wildfire or prescribed burning (wildland
fires), and agricultural burning sources. These sources are reported as nonpoint to EIS. However, EPA and other
agencies do need the day-specific, location-specific information for fire emission for air quality modeling
platforms. Thus, for the purposes of this plan, the approaches described here assume use of the EIS to submit
activity data (day-specific, location-specific information) and voluntary participation from S/L/T agencies to help
EPA to create the most accurate inventory of these sources. We encourage states to submit inputs (activity data)
using EIS and not emissions for Fires. We also encourage S/L/Ts to accept EPA emission estimates if a S/L/T has
no activity to submit. Note that the NEI process for Fires allows S/L/Ts to review our draft emission estimates
and make comments that EPA can address in moving to the final estimates, as one way of "accepting EPA
estimates."
Air agency Fire (day-specific emissions from wildfire and prescribed burning sources) data is an important source
of data in the NEI, as many pollutants such as PM, VOCs and numerous HAPs are emitted in significant amounts
by the large fires. For Fires, the EPA provides a default dataset that covers the entire U.S (including AK, HI, PR,
and the Virgin Islands). States should carefully check these emissions and strongly consider accepting them
before deciding to submit emissions on their own. The EPA prefers to use consistent methods and pollutants
where possible, so working with EPA to have the best estimates possible and then accepting EPA's estimates are
an ideal approach. After review of EPA's final fire emissions (after provision of activity data), if an Agency deems
it necessary to submit emissions, then care must be exercised to keep the pollutant coverage the same as what
EPA estimates using its methods. More details on the inventory development for wildland fires is provided here.
1. Reassembly of the Fires Workgroup
We will hold calls on a periodic basis to understand EPA methods, get work group comments and
suggestions, and incorporate comments to the best of our ability into our estimation process. We will also
include agricultural fires in these discussions.
2. Solicitation of 2023 Activity Data
EPA will send a request by email to all S/L/Ts to collect activity data for wildland fires and agricultural burns.
These activity data include, but are not limited to, fire-occurrence input data such as: acres burned, fuel
moisture, fuel consumption and type of fires. EPA will provide instructions on how to submit fire activity
using EIS.
3. Memo to S/L/Ts on Fires process for 2023
EPA will send a memo briefly explaining EPA methods and why EPA would prefer S/L/Ts and others to only
submit activity data for wildland fires and agricultural burns, and not emissions. In addition, if an S/L/T
chooses to submit emissions, we will explain what needs to be submitted (including CAPs, HAPs, and GHGs-
-and EPA will provide appropriate EFs) including parameters needed for emissions modeling such as the heat
released by each fire and its unit of measure and how one can estimate that value.
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4. Questionnaire to S/L/Ts
Concurrent with the memo to S/L/Ts on fires inventory process, a questionnaire will be sent to S/L/Ts to
help EPA assess how complete their activity data is. This will help EPA appropriate use other datasets in
conjunction with what the S/L/Ts submit. It is extremely helpful for S/L/Ts to fill out and submit the
questionnaire, even if you decide to submit emissions.
5. EPA Communication back to S/L/Ts
EPA will provide feedback to S/L/Ts that submitted activity data as to the quality of the submitted activity
data and if/how those data can use in emissions processing. EPA will further use survey completeness
results to ensure S/L/Ts are agreeable to bringing in new activity datasets that are available as default for
their domains.
6. Create SMARTFIRE2/Bluesky Pipeline based draft emission estimates for S/L/T review
Activity data agreed upon to for use by S/L/Ts for their areas will be used with or without other activity
datasets to estimate emissions via the SMARTFIRE2 (Satellite Mapping Automated Reanalvsis Tool for Fire
Incident Reconciliation)/Bluesky Pipeline(SF2/BSP) system approach that has been used for the 2020NEI. For
those S/L/Ts that did not submit activity data, default activity data will be used. Draft methodology will also
be provided and request S/L/Ts provide comments for corrections, including revised activity data they may
possess. For the initial draft 2023 WLF emissions, EPA may run the SF2/BSP model without any state-
submitted activity information (even if we receive it prior to that run). Once these draft estimates are
posted, EPA will use the resulting comments and any activity data provided to EPA by S/L/Ts to rerun the
SF2/BSP model. The reason for this is due to the uncertain nature of resource allocation for developing WLF
emissions estimates in the many NEI cycles.
7. Rerun SMARTFIRE2/BlueSky and agricultural burn emissions process with revisions
A regeneration of emissions based on suggested revisions from the review process as well as inclusion of
S/L/T submitted activity data will be performed as resources allow. Accompanying documentation outlining
differences between the draft estimates and this rerun will be provided. S/L/Ts that do not comment should
see no changes in emissions.
8. Finalizing Wildland fires and agricultural burning emissions inventory
S/L/Ts will be able to review the SMARTFIRE2/BlueSky and agricultural burns rerun emissions and minor
comments, or edits, will be addressed and reflected in the Final NEI. Any S/L/Ts that do approve of the EPA
estimates need to have submitted their emissions prior to the extended-AERR deadline -though we strongly
discourage this for wildland fires. For those S/L/Ts that submit emissions, EPA will provide HAP and PM2.5
composition emission factors for S/L/Ts to use. Also, if S/L/Ts submit emissions, they must also have
submitted other parameters required for emissions modeling, such as hear released by each fire (which can
be estimated from CONSUME). All required parameters will have been provided by EPA prior to the AERR
submittal deadline.
9.2 Fire approach changes
For the 2023 NEI process, we expect the following items to be new/changed from the 2020 NEI process:
Similar to the 2020 NEI, we continue to strongly-encourage S/L/Ts to submit activity data and NOT
emissions for this data category. While we do encourage all S/L/Ts to submit only activity data, a couple
of states do continue to submit emissions for this category.
As in the 2020 NEI, more parameters are required if S/L/Ts submit data (emissions) to this category,
including heat content ("Heat Release" and "Heat Release UOM"see step 3 in the previous section for
further details) for each wildland fire as well as other parameters needed for emissions modeling of
these fires; without heat release and heat release unit of measure, it is not possible to compute plume
rise for fires. It's also possible that we update HAPs and EC and OC EFs for these fires in the 2023 NEI.
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Those Agencies that decide to submit wildland emissions data must submit smoldering and flaming
emissions. The smoldering and flaming components individually are important for many activities
including use of data for climate assessments, because the PM2.5 chemical composition is different for
the smoldering vs. the flaming component. If a S/L/T does submit emissions, the smoldering component
should correspond to the "Residual Smoldering" component that comes out of the CONSUME model, for
example. Flaming can include both "flaming' and "regular smoldering". Note that if an S/L/T does submit
emissions, they will be prohibited from submitting a total, they will only be able to submit smoldering
and flaming emissions. If S/L/Ts only have total emissions and they need to re-apportion to the flaming
and smoldering components, then they can use EPA estimates to develop those needed ratios or consult
with EPA about the best way to solve the problem. EPA will provide instructions on how to submit
emissions data. EPA will sum up the emissions submitted by an Agency to monthly, county totals and
EPA will submit these summed totals to EIS. S/L/T agencies will not be able to submit monthly, county
totals to EIS for wildland fires, but can submit agricultural burn emissions to EIS as has been done in
previous NEIs.
S/L/Ts that submit emissions must also submit HAPs, GHGs, and PM species as reported in EPA data. EPA
will provide the requisite EFs.
By July 2024, EPA will decide which version of the BSP process will be coupled with SMARTFIRE2 to
estimate emissions. EPA is planning to use updated emissions factors from the Smoke Emissions
Reference Application (SERA) database for the 2023 NEI. More information on SERA can be found here:
https://depts.washington.edu/nwfire/sera/index.php. It is important to note that SERA uses numerous
publications for emissions factor information on different fire types and fuels. The PM emissions will
very likely increase significantly with the change in BSP to use the SERA database.
For the 2023 NEI, it's possible a new set of SCCs will be included for pile burns. This will be included in
the technical memo provided in the activity-data collection memo. If this is included, EPA will estimate
pile burn emissions, and the new SCCs will allow for S/L/Ts to submit pile burn emissions, if they choose
to submit emissions. S/L/Ts can accordingly also submit activity data (and questionnaire responses) for
this new category of fires.
Agencies should make it clear to the EPA that the activity data they are submitting is a complete set for
both prescribed, wildfires, and agricultural burns. In that way, the EPA will ensure no other default data
is brought into the process of estimating emissions for the S/L/Ts in question if such a note is included as
part of the activity data submission. This will be accomplished as it was in the 2020 NEI process by EPA
sending out a questionnaire that will address how complete an Agency's activity data are.
We encourage agencies to send in activity data as soon as possible after EPA's "request for 2023 WLF
and agricultural burn activity data" note goes out. Due to resource constraints this year and the fact that
EPA's draft estimates will be based on only national default activity data, EPA will likely provide more
time for S/L/Ts to submit activity data. We strongly encourage all agencies to review and comment on
the draft fires NEI that we expect to post in the summer of 2024. This includes submitting additional
activity data, commenting on the draft emission estimates, and other items that will facilitate getting us
to a final WLF inventory.
By July 2024, EPA will decide whether we need to add SCCs to cover pile burning.
10 EIS Gateway, Reports, and Tools
10.1 CERS Schema Changes
Through the Consolidated Air Emissions Reporting (CAER) project, several new fields have been identified to be
stored in EIS. We have taken this opportunity to add other fields that we have added to EIS over the years to the
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CERS XML Schema. The 2020 inventory was the first inventory year to use the new schema. More information
on these changes are provided in Section 4.1.1 and can also be found here.
10.2 Bridge Tool
The EIS Bridge Tools were modified to work with the updated CERS Schema format for the 2020 inventory. This
included new columns for existing items, as well as the new facility control structures. The revised bridge tools
were updated in December 2021 for Nonpoint/Onroad/Nonroad and February 2023 for Facility Point.
10.3 Reports
Along with the 2023 planned addition of input templates in EIS, new reports will be available for viewing what
templates your S/L agency has submitted as well as those submitted by other agencies. It has long been a
request to have the ability to view other agency templates to compare and confirm submissions across
templates by different agencies. The summary reports should include the ability to request your agency's
submissions, or another agency. In addition, we hope to include a template comparison report to view multiple
agency template submissions in the same report.
The EIS comparison reports were new for the 2020 cycle, and allow you to compare any number of datasets
against a single, user-specific base dataset. This could be used, for example, to compare point emissions in the
2020 NEI against your agency submitted data for 2023. An additional example would be to compare your
submitted data against TRI data so that you can see what facilities have reported to TRI and what is being
reported by your agency. The comparison reports provide an absolute difference, percent difference and ratio
between the baseline data value and the comparison value for each dataset being compared. We encourage
S/L/T air agencies to take advantage of this report after having made your submission as an additional QA tool.
In addition, reports will be available for assessing whether your submissions have met the 2023 NEI
completeness criteria. The use of this completeness report is described in Section 5.
11 Conclusion and Points of Contact
The EPA has created this plan to assist S/L/T agencies with their own planning needs for the 2023 NEI cycle.
Please direct comments on this plan to Rich Mason. The EPA recognizes that S/L/T air agency staff will have
many questions, ideas, and improvements that we have not addressed here, and your comments will help us
improve this plan and the 2023 NEI process. Points of contact for various NEI data source categories and
functions are provided on the Air Emissions Inventories Points of Contact website.
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