Local scale plume model for nitrogen oxides. Verification.

Typ: Rapport
Serie: RMK 50
Författare: Persson, Christer


A plume dispersion modet on local scale (0 - ~20 km) including atmospheric chemistry for nitrogen oxides was developed and presented in RMK 41 (1984). The model is designed for and used in practical environmental planning for e.g. coalfired power plants. In this study a verification of the model by means of plume data from several European power plants has been performed. The verification shows that the model is capable of describing the NO2- formation in power plant plumes in most weather situations in a fairly accurate way. No important systematic errors seem to be present and the correlation coefficient for NO2-fractions of total NOx is found to be about O.7 out to at least 1000 seconds after emission.The calculations are based only on routine meteorological data, emission data and ozone concentrations in the ambient air. Thus, the calculations have been performed in the same way as in the case of practical environmental planning, which gives a realistic picture of the potential of the modet for practical applications. From the results it is obvious that the meteorological conditions and the ambient ozone concentration are of great importance for the relative amount of NO2 in the plume. On a local geographical scale the plume chemistry is controlled by the entrainment of ambient air.