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How can I tell how different the NEI Selection
is from the data I submitted?
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EPA-454/B-19-010
May 2016
How can I tell how different the NEI Selection is from the data I submitted?
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Air Quality Assessment Division
Research Triangle Park, NC
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How can I tell how different the NEI Selection is from the data I submitted?
EIS provides emissions summary reports that can be run on request for different aggregation levels for
as many or as few pollutants as you wish, and filterable by geography. At this time EIS does not yet have
any "comparison" report feature, so the basic approach is that you would request two separate reports
with the same filters, one on the NEI selection and one on your own emissions dataset, and then put the
two reports side-by-side to identify differences. You may want to start at an aggregated summary level
to quickly determine the overall magnitude of the differences, or you could go directly to the most
detailed level to see all instances where an EPA emissions value was used, and whether any State value
was available for that process.
EIS Report Basics
To obtain EIS reports, go to the EIS Gateway main page. On left-hand navigation panel, choose "Request
Reports". From the Request Reports page, go to Emissions Summaries. For the most high-level
comparison, choose "By Geography". From the "Emissions Summaries by Geography" page, choose the
"State/Tribe by Data Category" report, and then set the States filter to your State. This will limit the
report you request on the NEI selection to just your State. If you wish to also limit your comparison to
just one Data Category (point, nonpoint, onroad, nonroad, or event), use the Data Categories filter to
make your selection, or leave the filter as is to get all data categories. Under the Pollutants filter you
must make a choice from "AN", "CAPs", "HAPs", or you can select one or several specific pollutants that
you'd like to see in the report. Under the Data Set or Selection filter, first choose "2014 NEI draft VI"
and then hit the "Request Download" to request your first of two reports to compare. Then hit the "Edit
Report Criteria" button, go back to the Data Set or Selection filter, and this time choose your State data
set for 2014, and then Request Download. In approximately 30 minutes your two requested reports
should be available from the "Report Downloads" link on the left-hand navigation panel. For a State
total for Point data category for all pollutants pair of reports, open each report in Excel, sort each by
pollutant name or pollutant code, copy the second report's set of pollutants onto the first sheet, and
write an Excel formula to subtract the State dataset sums from the NEI selection sums. Results greater
than zero will show where some EPA dataset was used to add additional emissions for that pollutant.
Negative results would be unusual, and would indicate where some of the emissions reported in your
State dataset had been "tagged out" and therefore not used for the NEI selection.
Please note that if there are local air agencies that report emissions for some of the counties in your
State, then you should not expect agreement between a State-total filter of the NEI selection and the
emissions reported in just your State agency's individual dataset. In this case, you should start by
choosing the "County by Data Category" report type, and filtering the NEI selection report for all the
counties for which you do report as part of your State agency dataset. In this case you would get
emissions sums for each County and each pollutant, and so you would have more detailed set of
comparisons. If you are a local agency, the County by Data Category, filtered to the counties of interest
would also be the appropriate choice of report.
Point Source Detail Reports
For point sources, you can get more detailed reports than the by Geography sums by choosing the "By
Facility" option from the Emissions Summaries section. You can then choose from one of four report
types - Facility, Emission Unit, Emission Process, or Release Point. The Facility and Emission Process
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reports are probably of most interest if you are trying to see where data beyond S/L/T-reported data has
been included as part of the NEI selection. The Emission Process report has the advantage that it
includes a field showing the Data Source of each process-level pollutant value. A report on the NEI
selection will therefore show either the S/L/T dataset as the source or any of a number of EPA datasets,
such as 2014EPA_TRI, 2014EPA_HAP-Aug, 2014EPA_Airports, etc. Filtering on this field in the single NEI
selection report will therefore show all data added beyond the State's dataset. If you wish to see if
there were any values reported in the State dataset that were not used in the NEI selection but were
instead replaced with a value from an EPA dataset, run a full Emission process level detail report on your
State dataset, then link that table to the NEI selection process-level report using EIS process ID and
pollutant code, then filter the results for any rows where the data source field from the NEI Selection
table shows something other than the State dataset name.
Data Tagging Report
Emissions values can be individually "tagged out" in EIS, to prevent them from being considered for use
in an NEI selection. This is most commonly done in the point source data category to prevent EPA TRI or
other EPA dataset values from being used either ahead of or in addition to (double-counting) existing
State values. However, tagging can be applied to values in any dataset, including the State datasets.
The typical reason for tagging a State-reported emissions value in the point data category would be if
the value were suspected of being a gross outlier, on the high side. Tagging of such State-reported
values may be done either with or without any alternative emissions value from an EPA dataset being
available as a replacement.
A report of any values tagged out in the State dataset can be obtained from the same EIS "Request
Reports" page, section named "Data Tagging Summaries", the next to last section listed. Select the year
and dataset name desired, the data category, and the Tagging Type ("Only Tagged Values" suggested) to
see if there are any currently tagged out emissions values in your State dataset. It is not uncommon for
there to be no such values in a State dataset if you have reviewed and resolved all of the largest flagged
items during the QA review period.
How can I correct EPA Augmented data?
Only the Agency that owns the dataset may edit or delete emissions records in that dataset. Just as
State emissions datasets cannot be edited by EPA, the EPA datasets (those used as the source for
augmented data) cannot be edited by States. Two methods exist to address the use of augmented data
that you believe to be inaccurate. If the augmented data exists in the NEI selection because there was
no State-reported value, you can add a State-reported value to your dataset during the draft review
period. Valid State-reported additions will be used in the selection for the final NEI. (If you have already
reported an emissions value to EIS but it is not being used for selection because it is tagged out, and you
believe it to be accurate, please contact EIAG to request the tag to be removed). If you do not have or
do not wish to provide any State-reported value but believe the augmented value to be significantly
inaccurate, you can contact EIAG and request that the value be tagged out from the EPA dataset for the
final selection, with no replacement.
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To make additions or edits to your own dataset during the draft review period, please contact EIAG by
email to request the EIS Production Environment point submittal window for 2014 be opened to accept
your edits, either via batch xml or by individual on-line EIS Gateway editing. If using batch xml for edits
or additions, we request that you either submit small xmls that address only the specific processes or
facilities requiring editing. To request that EPA make edits to any of its augmentation datasets, please
provide by email the details of facility, unit, and process IDs, the pollutants, and the current NEI
selection emissions values that you would like to be tagged out, and the reasons you believe the values
to be inaccurate.
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United States Office of Air Quality Planning and Standards Publication No. EPA-454/B-19-010
Environmental Protection Air Quality Assessment Division May 2016
Agency Research Triangle Park, NC
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