United States
 Environmental Protection
 Agency
Atmospheric Sciences
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S8-86/042 Apr. 1987
Project Summary
Addendum to PTPLU:  A Single
Source Gaussian  Dispersion
Algorithm
Thomas E. Pierce
  PTPLU  (PoinT PLUme dispersion
model) was developed by the U.S. En-
vironmental Protection Agency (EPA)
in 1982 to function as a screening
model for estimating maximum hourly
concentrations from  single point
sources.  This addendum  describes
modifications  to PTPLU that have re-
sulted in an update of the FORTRAN
source code as contained in UNAMAP
(Version 6).   V
  This Project Summary was developed
by EPA's Atmospheric  Sciences Re-
search Laboratory, Research Triangle
Park, NC, to announce key findings of
the research project that Is fully docu-
mented In a separate report of the same
title (see Project Report ordering In-
formation at back).

Summary of Modifications
  In 1982, PTPLU was introduced as an
improvement over PTMAX. Both models
were intended for use as point source
screening  models in which maximum
short-term concentrations were estimated
for various meteorological conditions.
PTPLU's improvements over PTMAX in-
cluded wind profile exponents, momentum
and buoyancy driven  plume rise, and
options for calculating buoyancy induced
dispersion, stack tip  downwash, and
gradual plume rise.
  This new version of PTPLU,  Version
2.0, offers enhancements to the original
PTPLU algorithm. In Version 2.0, we offer
a choice of either urban or rural dispersion
coefficients and wind profile exponents,
and an option for selecting default values.
  This addendum describes the changes,
presents a test case, and shows FORTRAN
coding changes that were made in the
batch version of PTPLU. Both the inter-
active and batch versions of PTPLU-2.0
were included in UNAMAP, Version 6,
which was released August 1986.

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     The EPA author Thomas E. Pierce is with the Atmospheric Sciences Research
       Laboratory, Research  Triangle Park. NC 27711.
     D. Bruce Turner is the EPA Project Officer (see below)
     The complete report, entitled "Addendum to PTPLU A Single Source Gaussian
       Dispersion Algorithm," (Order No. PB 87-145 363/AS; Cost: $9.95, subject
       to change) will be available only from:
            National Technical Information Service
            5285 Port Royal Road
            Springfield, VA 22161
            Telephone: 703-487-4650
     The EPA Project Officer can be contacted at:
            Atmospheric Sciences Research Laboratory
            U.S. Environmental Protection Agency
            Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use S300
EPA/600/S8-86/042
             OCQ0329   PS
                                             AGENCY

                                             60604

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