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CDM: Climatological Dispersion Model

CDM (Climatological Dispersion Model) is a classical air pollution model based on the gaussian approximation and aimed at computing the long term (monthly and annual) averages of air pollution concentration in an urban area. The concentration at any number of receptors is computed as the result of up to 2500 areal and 200 point sources on flat terrain. It can compute two pollutants at the same time and has been used for both SO2 and NOX.
The program is similar to AQDM, but uses a different method to compute the effect of areal source, the plume rise, and the wind velocity at different heights.


area: air quality
objectives: simulation
description: gaussian plume, areal sources, point sources, urban site,long term.


You can download the software from
EPA - SCRAM Models

or directly: http://www.epa.gov/scram001/models/othreg/cdm2.zip

The model is part of UNAMAP (version 6). The code is available on diskette at:
Computer Products
National Technical Information Service
U.S Department of Commerce
Springfield, Virginia
tel (703) 487- 4650.


J. S. Irwin
Atmospheric Sciences Research Laboratory
RTP, NC 27711
T. Chico and J. Catalano
Aerocomp, Inc.
3303 Harbor Boulevard
Costa Mesa, CA 92626


  • G.A.Briggs,"Plume rise", U.S.Atomic Energy Commission Critical Review Series, Oak Ridge National Laboratory, Oak Ridge, TN (NTIS No. TID- 25075), 1969
  • G.A.Briggs, "Diffusion estimation for small emissions" USAEC report ATDL-106. U.S. Atomic Energy Commision, Oak Ridge, TN, 1974.
  • G.A.Briggs, "Plume rise predictions", Lectures on air pollution and environmental impact analysis. Workshop proceedings, Boston, Mass., Sept. 29- Oct. 3, pp. 59-111. American Meteorology Society, Boston, Mass, 1975.
  • K.L.Calder, "A climatological model for multiple-source air pollution", proc. 2nd Meet. North Atlantic treaty Organ.-Comm. Challenges Modern Soc. Expert Panel Air Pollut. Modelling, Paris, 33 pp., 1971;
  • EPA-450/2-78-027R, GUIDELINE ON AIR QUALITY MODELS, U.S. Environmental Protection Agency, 1986.
  • F.A.Gifford, "Turbolent diffusion typing schemes-- A review. Nuclear safety, 17:68-86, 1976.
  • F.Pasquill, Atmospheric dispersion parameters in gaussian plume modeling part II possible requirements for change in the Turner Workbook values.
  • EPA Publication No. EPA 600/4- 76-030b. U:S Enviromental protection Agency, research trianglre Park, NC.
  • J.W.S.Young, "The overlay technique - a simple approach to the topography problem, 1, long term concentrations", Atmospheric Pollution,pp 193-8, 1978.


  • T.M.Brown, J.S.Irwin, "A sensitivity analysis of the treatment of area source by the climatological dispesion AQDM: air quality display model, 1972;
  • A.D.Busse, J.R.Zimmerman, "User's Guide for CDM. EPA Publication No. EPA r4-73- 024, 1973.
  • R.D.Londergan, D.Minott, D.Wachter, "Evaluation of urban air quality simulation Models, EPA Publication No. EPA 450/4-83- 020, 1983.
  • J.R. Zimmermann, "Some Preliminary Results of Modeling from the Pollution Study of Ankara,Turkey", Proceedings of the Second Meeting of the Expert Panel on Air Pollution Modelling,Nato Committee on the Challenges of Modern Society,Paris, France, 1971.
  • J.R.Zimmerman, "The NATO/CCMS Air Pollution Study of St.Louis,Missouri", presented at the Third Meeting of the expert Panel on Air pollution modeling, NATO Commitee on the Challanges of Modern society, Paris, France, 1972.



Estratto dalla banca modelli del progetto CEE GAIA INCO - www.ess.co.at/GAIA