TRANSFER OF DISPERSION CATEGORY STATISTIC S WITH THE BRENK METHOD - UNCERTAINTIES AND POSSIBLE ERRORS

In order to calculate the annual mean and 98-percentile values of ambi ent air concentrations, a set of representative wind and dispersion pa rameters at the investigated area is required. In most cases, such dis tinct data are not available and dispersion parameters of the closest adjacent meteorological station have to be transferred to a measured w ind statistics at the examined location. With the Brenk method, which is mostly used for these cases, the physical dependence between wind d irection, dispersion parameters and wind velocity will be lost. Two ca lculations are presented for an arbitrarily selected case study, showi ng that - if applying a Brenk modified statistics - the resulting maxi mum error in ambient air concentration will be about +/-20% for the an nual mean and about 50% for the 98-percentile value.