The addendum applies to the 'User's Guide for MPTER -- A Multiple Point Gaussain Dispersion Algorithm with Optional Terrain Adjustment' of Pierce and Turner, 1980. While the cited document describes the features of the MPTER model, its technical basis, and applications, this addendum deals exclusively with algorithm modifications to accommodate new knowledge and technique as well as address recommendations of the 'Guideline on Air Quality Models.' The Guideline lists MPTER as a preferred model for calculating concentrations due to point sources at averaging times from one hour to one year in rural or urban area where the terrain is flat or gently rolling and pollutant transport distances are less than 50 kilometers. The original version of the model offered options for stack-tip downwash, gradual plume rise, and buoyancy-induced dispersion. Added to this release (UNAMAP Version 6) are options that allow selection of either rural or urban dispersion parameters and wind-profile exponents. To address model over-prediction when wind speeds are low, an algorithm for the treatment of calms has been added. Also new in this release is a default option to set parameters for regulatory applications as suggested by the Guideline. These are: final plume rise, rather than gradual rise, is used and buoyancy-induced dispersion and momentum plume rise are considered, as are calm conditions.

Includes bibliographical references (pages 144-145, 154). "NTIS PB86-217163/AS." "EPA/600/8-86/021." Cover title. "Contract No. 68-02-4106." "D. Bruce Turner, Project Officer." "Russell F. Lee, Technical Advisor." "Jerome B. Mersch, Revised Code Author."