Dispersion calculation
A calculation method for determining the spread of air pollutants in the lower troposphere is called dispersion calculation . In Germany, the framework conditions for their implementation are regulated by the TA Luft . Propagation calculations are four-dimensional processes in space and time.
Basics
As a rule, dispersion calculations are required for forecasts about the spread of pollutants or odorous substances . The most important factors influencing the spread of pollutants are the wind and stratification of the earth's atmosphere . However, the latter can only be measured with great effort and is therefore estimated in practice using the time of day and season as well as cloud cover and wind speed . The result is one of the six dispersion classes “very stable”, “stable”, “indifferently stable”, “indifferently unstable”, “unstable” or “very unstable”. On this basis, the further calculation takes place under quasi-stationary conditions. The result is a functional relationship between the concentration of the pollutant and the distance to the emitter . Unstable conditions result in higher loads in the immediate vicinity and stable conditions result in a load that increases only slowly with distance, but which is also much more widespread.
application
Dispersion calculations are used in licensing practice to predict the additional loads caused by a system. With the help of dispersion calculation and source term back calculation, the diffuse emissions from an industrial plant can also be determined.
Individual evidence
- ↑ Kai Vaupel, Julian Schelp, Ulrich Klenk, Eberhard Schmidt : Structural relationships in modeling the dispersion of airborne pollutants in the earth's atmosphere. In: Hazardous substances - cleanliness. Air . 76, No. 7/8, 2016, ISSN 0949-8036 , pp. 299-302.
- ↑ a b VDI 3783 sheet 13: 2010-01 environmental meteorology ; Quality assurance in the immission forecast; Plant-related immission control; Dispersion calculation according to TA Luft (Environmental meteorology; Quality control concerning air quality forecast; Plant-related pollution control; Dispersion calculation according to TA Luft). Beuth Verlag, Berlin, pp. 2–3.
- ↑ VDI 3782 sheet 1: 2016-01 environmental meteorology ; Atmospheric dispersion models; Gaussian plume model for the determination of ambient air characteristics (Environmental meteorology; Atmospheric dispersion models; Gaussain plume model for the determination of ambient air characteristics). Beuth Verlag, Berlin, p. 19.
- ↑ VDI 4285 sheet 3: 2015-11 Metrological determination of emissions from diffuse sources; Quantification of diffusive emissions from industrial plants including agricultural sources (Determination of diffusive emissions by measurements; Quantification of diffusive emissions of fine dust from industrial plants including agricultural sources). Beuth Verlag, Berlin, p. 9.