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Tom, Thanks once again for your excellent work on this once again. I’ve
merged the latest information into the page set up previously for this topic on
the wiki: We should us a portion of our upcoming Steering Committee call
(Jan 16, 1:30pm EDT) to discuss this latest content and what the next steps
are. I think a reasonable near-term goal may be to have a first iteration of a
revised regional emission factor database. If others in the group haven’t done so, please take a few
minutes to review the material. Jon From:
owner-airtoxics@great-lakes.net [mailto:owner-airtoxics@great-lakes.net] On
Behalf Of Tom Velalis Final
Evaluation of WebFire Records I completed the
review of the WebFire factors. Below is my write up and attached is an
Excel file with observations and recommendations. Background In the last
conference call, we discussed the need to evaluate and compare WebFire
records. In order to accomplish this task, a number of processing steps
and a methodology that compares and contrast the records are needed(previous
emails). It is not possible to review every single emission factor for
all processes. However, it is possible to review the uncontrolled
emission factors from similar SCCs. Groups are formed
for SCCs that can be combined based on common material and type of
process. Only 500+ SCCs are included for this evaluation but they account
for the majority of the WebFire emission factors. SCCs that that do not
belong to those groups, are more difficult and less important to evaluate. Procedure 64 pollutants are
targeted for this evaluation. Pollutants are selected based on importance
and availability of emission factors. A worksheet is prepared for each
pollutant and combined into five data sets: Priority_Pollutant_List64_PAHs.xls
(PAHs and Dioxins) Priority_Pollutant_List64_PM_HAPs.xls
(HAPs in particulate form) Priority_Pollutant_List64_VOC_HAPs.xls
(HAPs in volatile organic vapor form) Priority_Pollutant_List64_MISC-HAPs.xls
(Miscalleneus HAPs) Priority_Criteria_PM_VOCs.xls
(Particulates and Volatile Organic Compaunds) The records in each
worksheet are sorted by Group and SCC. The records within each group are
reviewed for consistency with each other. Records that are different by a
factor of 10 are highlighted as inconsistent. For each highlighted group and pollutant
combination, the source of the emission factor is reviewed and recommendation
is made for further action. The results of the
evaluation are stored in the attached spreadsheet Evaluation_Group_Factors.xls. Conclussions The evaluation
Excel file has three worksheets. Each worksheet is put together to
account for emission factors with similar issues. Based on observation,
the following conclusions are derived:
Recommendations
Discussion
Point EPA
developed an Emissions Reporting Tool (ERT) to update WebFire with quality
assured stack test results. If ERT is engaged by States and regulated
community, it will add thousands of records in WebFire and the degree of
variability will be potentially enormous. It will also make it
exponentially more difficult to quality assure the database. Although it
is a great idea to capture the data in one database, EPA should re-think how to
manage the data. In my opinion, EPA should develop a calculation protocol
to derive emission factors for tested pollutants. Those emission factors
should be compared against existing WebFire records and, if different by a certain
factor, replace the existing factor with the new factor. Since WebFire is
a generic listing of emission factors, only one emission factor is needed for
each process and pollutant combination. States do not need a database of
millions of records. States need a quality assured and accurate database
of emission factors.
Future
Steps
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