THE TEXT YOU ARE VIEWING IS A COMPUTER-GENERATED OR RETYPED VERSION OF A
PAPER PHOTOCOPY OF THE ORIGINAL. ALTHOUGH CONSIDERABLE EFFORT HAS BEEN
EXPENDED TO QUALITY ASSURE THE CONVERSION, IT MAY CONTAIN TYPOGRAPHICAL
ERRORS. TO OBTAIN A LEGAL COPY OF THE ORIGINAL DOCUMENT, AS IT
CURRENTLY EXISTS, THE READER SHOULD CONTACT THE OFFICE THAT ORIGINATED
THE CORRESPONDENCE OR PROVIDED THE RESPONSE.
4.15
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
DATE: FEB 13 1981
SUBJECT: Baseline Date in Determining Net Emissions Increases
FROM: Darryl D. Tyler, Acting Director
Control Programs Development Division (MD-15)
TO: Allyn M. Davis, Director
Air and Hazardous Materials Division, Region VI
We have reviewed your January 28, 1981 memorandum in which you request
guidance regarding the relevance of baseline date to the determination of
creditable contemporaneous increases and decreases under the PSD
regulations. Our response is as follows.
As you noted, emissions changes can be considered "contemporaneous"
only if they occur no more than 5 years before the commencement of
construction of the particular changes being considered. 40 CFR 51.21
(b)(3)(ii). There is, however, a limitation on this 5 year period: 40 CFR
52.21(b)(3)(iv) makes any increase or decrease in emissions of sulfur
dioxide (SO2) or particulate matter (PM) creditable in this netting process
only if it is required to be considered in computing the amount of increment
available. This means that no changes in emissions of SO2 or PM commencing
prior to January 6, 1975 would be considered in determining net emissions
increases.
Your question also addresses the treatment of carbon monoxide (CO)
emissions changes in determining net emissions increases. The answer is
that criteria pollutants other than SO2 and PM, such as CO, are not subject
to the limitation contained in Section 52.21(b)(3)(iv); thus, one looks only
to the 5 year period proceeding the commencement of construction of the
modification triggering netting in determining which emissions changes will
be netted. It is possible that the PSD Set II program will develop
increments for these pollutants and extend the limitations contained in
Section 52.21(b)(3)(iv) to them. Until such time, however, no such
limitation exists for CO emissions reductions.
I trust that this has been responsive to your request. Please contact
Mike Trutna of my staff at 629-5292 if you have any further questions on
this matter.
cc: W. Barber
E. Reich
B. Diamond
|