Extract of VDI 3782 Part 1 published by
Dispersion of Pollutants in the Atmosphere
Model for Air Quality Management
This Guideline describes a procedure for calculating ambient air
concentrations and vertical mass fluxes of anthropogenic emissions in the
vicinity of single or multiple sources for a distance up to 100 km. This area
must be flat and enable undisturbed dispersion, with a wind velocity higher
than 1 m/s.
The computing procedure 1) which is described in this
Guideline can be used for gases, suspended particles (aerosols), and depositing
dusts. In a first approximation, it accounts for dry and wet deposition as well
as for chemical transformations. By the introduction of mean mixing layer
heights, limitations of the vertical exchange are taken into consideration.
Sources may consist of point, line, area, or volume sources.
Up to twelve different emission states can be taken into account.
As a result of calculating the ambient air concentrations and the
vertical mass flux, values of seasonal or yearly averages as well as
percentiles of the distribution of half hour averages, related to one month,
one season or one year, may be obtained. Data for shorter periods are not
sufficiently valid from the statistic point of view.
Therefore, this guideline can be used especially for the analysis of
ambient air concentrations in relation to emitting sources, but also for
multiple source systems (air quality management).
The procedure described in this guideline, however, cannot replace
calculating procedures which are also based on a Gaussian method, but which are
integrated in a closed system of air quality management, which is characterized
especially by a fixed temporal and spatial reference of the ambient air
concentration (e.g., computing procedures according to TA Luft 86).
This Guideline also deals with the unregulated field of multiple source
The requirements which are needed for the input data with regard to the
sources and the decisive meteorological parameters are listed, followed by the
description of the procedures for determining the dispersion category as well
as the dispersion parameters.
The influence of buildings and different kinds of terrain is dealt with
in the guidelines VDI 3781 Part 6  and VDI 3783 Part 6 .
The conditions for applying this Guideline are to be checked thoroughly
by competent experts.