CALPUFF is a multi-species non-steady-state puff dispersion model that simulates the effects of time and space varying meteorological conditions on pollutant transport, transformation, and removal. CALPUFF is intended for use on scales from tens of meters from a source to hundreds of kilometers. It includes algorithms for near-field effects such as stack tip downwash, building downwash, transitional buoyant and momentum plume rise, rain cap effects, partial plume penetration, subgrid scale terrain and coastal interactions effects, and terrain impingement as well as longer range effects such as pollutant removal due to wet scavenging and dry deposition, chemical transformation, vertical wind shear effects, overwater transport, plume fumigation, and visibility effects of particulate matter concentrations.
CALPUFF is appropriate for long range transport (source-receptor distances of 50 to several hundred kilometers) of emissions from point, volume, area, and line sources. The meteorological input data should be fully characterised with time-and-space-varying three dimensional wind and meteorological conditions using CALMET. CALPUFF may also be used on a case-by-case basis when the model is more appropriate for the specific application. The purpose of choosing a modelling system like CALPUFF is to fully treat stagnation, wind reversals, and time and space variations of meteorological conditions on transport and dispersion.
Beside the 3D meteorological fields developed by the CALMET diagnostic meteorological model, CALPUFF can use single station meteorological data stored in format used by other dispersion models (ISC3ST, AUSPLUME, CTDMPLUS). However single station meteorological files do not allow CALPUFF to take advantage of its capabilities to treat spatially varying meteorological fields.
CALPUFF produces files of hourly concentrations for each modeled species, wet deposition fluxes, dry deposition fluxes, and for visibility applications, extinction coefficients. The process and information flow needed to carry out the air dispersion study is represented in this figure below.
CALPUFF is currently developed by Exponent, Inc.
Sources: Scire J.S., Strimaitis D.G. and Yamartino R.J. (2000) A user's guide for the CALPUFF dispersion model (Version 5.0).