nnsrnet.txt

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         Texas Natural Resource Conservation Commission
                     Interoffice Memorandum

To:  Nonattainment New Source Review (NNSR) Team
From:  Dr. Kurt Kind, Chemical Section
Date:  December 4, 1995
Subject:  Requirement for NNSR Netting

Permit applicants are normally required to perform nonattainment
netting for any pollutants that have project emission increases
greater than the trigger level for the nonattainment area.  If the
emission netting results show that the total net project and
contemporaneous period emission increases are greater than the
applicable significance level, NNSR is required for the project. 
The NNSR review requires the permit applicant offset emission
increases at the appropriate ratio for the county and pollutant. 
The applicant may choose to offset the total net increase (project
plus the contemporaneous period) or only the project increase.  If
the second option is taken (offsetting the project increases), the
netting is used only to determine whether the project is subject to
NNSR review.

Due to this, the permit engineer does not need to require emission
netting if the permit applicant agrees that the project is subject
to NNSR and elects to offset the project emission increases at the
appropriate ratio.  In this case, the permit application will
undergo the most rigorous permit review (NNSR) and the netting
results would not impact that review.  It is important to note that
only the project that is offset will be considered relied on in the
issuance of a nonattainment permit and thereby excluded from future
netting for that pollutant.

Note that this does not apply to PSD review as emission netting
results are used as inputs to air dispersion modeling performed for
that permit review.  In this case, all contemporaneous netting is
considered relied on in the issuance of a PSD permit and must be
excluded from future netting for that pollutant.