APRAC-3: Emission and diffusion modeling package
The Air Pollution Research Advisory Committee model - APRAC-3
computes traffic pollution mainly in an urban area,
given a network of roads. It has been used to simulate the diffusion
of hydrocarbons, carbon monoxide and nitrogen oxides. Computationally,
it relies on the use of the gaussiam plume approximation, but
its more interesting feature is perhaps in the assistance in evaluating
The model package consists of three modules: a preprocessor of
emission factors (based on the program MOBILE1 from the US EPA),
the computation of emissions (both along the main traffic paths
and in each square of the grid in which the area under analysis
must be divided), the computaion of pollutant diffusion with specific
attention to the problem of urban canyons.
traffic pollution, gaussian plume,line sources, urban site, hydrocarbons,
pollutants from combustion, nitrogen oxides, short term
The model is part of UNAMAP and is available on magnetic tape from:
National Technical Information Service
U. S. Department of Commerce
Springfield, Virginia 22161
Phone (703) 487-4650
P. B. Simmon, R. M. Patterson, F.L. Ludwig, L. B. Jones
Atmospheric Science Center
333 Ravenswood Avenue
Menlo Park, California 94025
- EPA: "USER'S GUIDE TO THE APRAC 3 /MOBILE1 EMISSION AND DIFFUSION MODELING PACKAGE".
- J.L.Heffter, A.D.Taylor, "A Regional Continental Scale Transport
Diffusion And Deposition Model" Nat.Ocean and Atmos.Admin, 1975
- M.E.Holzworth, G.C.Miller, "An Atmospheric Diffusion Model
For Metropolitan Areas" J.Air Pollut. Control Association,
- K.B.Johnson, W.F.Dabberdt, F.L.Ludwig, R.J.Allen, "Field
study for initial evaluation of an urban diffusion model
for carbon monoxide" EPA, ContractCAPA-3-68, 1971
- F.L.Ludwig, W.F.Dabberpt, "Comparision Of Two Atmospheric
Stability Classification Schemes In A Urban Application"
- F.L.Ludwig, "Urban Air Temperatures And Their Relation To
Extra-Urban Meteorological Measurements"
Proc.Semiannual.Meeting Of Am.Soc.Heat.Refrig. and Air
Cond.Eng., San Francisco, 1970
- S.L.Mancuso, F.L.Ludwig, "User's manual for the APRAC-1A
diffusion model computer program" CRC and EPA, Contract
- H.Panosky, "Introduction to Dinamic Meteorology"
University Park, Pennsylvania, 1957
- F.Pasquill, "The Estimation Of The Dispersion Of WindBorne
- F.V.Webster, "Traffic signal settings, road research"
Technical paper no 37, Road Research Laboratory, H. M.
Station Office, London, Engliand, 1958