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RE: PCDD, PCDF questions
Tom,
the NEI pollutant code look-up table in the Code Look-up file posted in
documentation for the 2002 NEI point sources on CHIEF has the TEQ
factors that can be used to multiply mass (pounds/grams/ng, etc) of
individual congeners to generate a TEQ value. there are 2 TEQ schemes.
It is very important to identify the scheme you are using.
anne
"Tom Velalis"
<tom.velalis@epa
.state.oh.us> To
Sent by: "Congtru (ENE) Doan"
owner-airtoxics@ <Congtru.Doan@ontario.ca>
great-lakes.net cc
"Airtoxics"
<airtoxics@great-lakes.net>
12/24/2007 08:17 Subject
AM RE: PCDD, PCDF questions
Cong
Thanks for the information on TEQs. I had no knowledge or experience
with this issue prior to your response.
TEQ stands for Toxic Equivalent and its is the international standard
for measuring dioxin emissions. However, FIRE
is not using those units in the emission factors. Fire is only using
the unit of pounds for dioxins and that is what I use for the
State inventory. At this point, I have no provision for this unit in
the State compilation of emission factors.
Also, I have no practical understanding of the TEQ unit and how it is
expressed in an emission factor. I googled it and
noticed that its being used in conjunction with grams (g-TEQ). Look
below
http://www.dioxinfacts.org/tri_dioxin_data/news/tri_2003.html
Do you have any facilities in Ontario that report emissions in TEQ
units? How do you handle a report with
a process reporting emissions in lbs and another process reporting
emissions in TEQ units?
Tom.
>>> "Doan, Congtru (ENE)" <Congtru.Doan@ontario.ca> 12/21/2007 11:14 AM
>>>
Jon, Tom:
Thank for your responses.
Tom,
I interpret TEQ as a unit not a pollutant. Based on this, I believe you
mean “all dioxins, furans” have their own CAS number … Like other
pollutants, the emission units for congeners are lb, gram … However, the
unit “TEQ” is commonly used for PCDD, PCDF groups. One can calculate TEQ
values for each congener of each group then add them up and represent
the total as a single pollutant group (PCDD or PCDF) with TEQ unit.
So if one knows the emission for each congener, he/she can always
represent the PCDD, PCDF in any units (lb, gram, TEQ). Problem arises
when the unit of available emission of the group is in TEQ. It is not
possible to convert it back to the natural unit.
My question is that should we consider additional unit “TEQ” to RAPIDS
for the purpose of making use of PCDD, PCDF numbers that are in TEQ. The
consequence of adding this new unit is having two units for PCDD, PCDF!
What do you mean by saying “The Dioxin and Furan groups exclude the
TEQs” ? You subtract the total emission of the congeners from the total
or did not total up the emissions of the congeners to produce PCDD, PCDF
or just simply saying you do not use “TEQ” unit in PCDD, PCDF. Thanks.
Cong,
From: Tom Velalis [mailto:tom.velalis@epa.state.oh.us]
Sent: Friday, December 21, 2007 9:44 AM
To: Jon Dettling; Doan, Congtru (ENE)
Cc: 'Airtoxics'; Wong, Peter (ENE)
Subject: RE: PCDD, PCDF questions
Jon
I believe you provided an accurate response to Cong's question. Also,
that is the arrangment
used by NEI. Attached is Ohio's table of Pollutants which is based on
the NEI table. The Dioxin and Furan
groups exclude the TEQs. The Explanation is provided in the
HAP_CATEGORY_NAME. The TEQs have their own CAS number
and enjoy their own space in the pollutants table.
As far as units go, I have converted all Webfire units into unit of
mass, pounds (except radiocative units).
Tom.
>>> "Jon Dettling" <dettling@glc.org> 12/19/2007 5:29 PM >>>
Cong,
These are great questions and fit in well with the fact that PCDD/F are
among the chemicals we’ve identified to spend some effort on revising
our treatment of in the near future. Here are my initial responses,
which are open to discussion and correction by the group:
1) As with everything else, we store this data at the regional
level in pounds. Some inventories store these as grams or another
smaller unit to avoid the problem that we sometimes encounter that the
values are often so small when expressed in pounds that the 12 digit
field limits in our database can cause loss of data. For these
compounds, the input we’ve gotten from toxicologists is that even very
small quantities are important and we should not assume that if
something is many orders of magnitude less than a pound that it is
insignificant. I do not believe that we are including any data as TEQs.
It’s possible that we should be and that is one reason for wanting to
revisit our approach to these
2) Yes, the PCDD and PCDF groups represent the sum of all congeners
(by weight, not TEQ). The only exception is below. Someone correct me if
I am wrong.
3) No. Where we can quantify the 2378 congeners alone, those are
reported in these separate categories. The PCDD/F categories should not
include those numbers to avoid double counting. Again, someone correct
me if I’m wrong.
The answers above reflect how I believe we currently are dealing with
these categories, but that does not imply that this is how we should be
dealing with them. I think there is good rationale and data available to
be treating these categories differently than we do. Reviewing this,
especially in light of the EPA’s recent report, is on the to-do list for
the future.
Jon
~~~~~~~~~~~~~~~~~~~
Jon Dettling
734-274-5183
dettling@glc.org
From: Doan, Congtru (ENE) [mailto:Congtru.Doan@ontario.ca]
Sent: Wednesday, December 19, 2007 2:31 PM
To: Jon Dettling
Cc: Wong, Peter (ENE)
Subject: PCDD, PCDF questions
Hi Jon,
We have discussed about conventions on PCDD and PCDF few times. Could
you please let me know what conventions used by the group regarding the
units and congeners of PCDD, PCDF?
1. What are the actual units for PCDD, PCDF? Are they in absolute
mass unit or in TEQ? Should they be in TEQ?
2. Do the PCDD and PCDF represent the sum of all its congeners?
3. In RAPIDS regional report, do PCDD, PCDF including TCDD,2378 and
TCDF,2378 ?
Thanks.
Cong,
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