Comparing the calculated and measured aerosol concentrations and depositions around a metallurgical plant

The aerosol concentration and deposition around a metallurgical plant have been analysed. Measurements were carried out continuously over 14 months in order to obtain reliable data on the emissions, the local meteorological conditions and the ambient aerosol concentration and deposition levels. A bi-Gaussian dispersion model with source depletion has been used for the simulation of the aerosol concentration and deposition. The accuracy of the calculated short-term concentrations was better than 40 % while for the average depositions it was better than 60%. The dominating role of the fugitive compared with stack emissions was emphasized and the inevitable inaccuracies in the simulation of these sources were demonstrated. The fall-out velocity for the ISO deposit gauge was experimentally determined and interpreted with respect to the sampling conditions. Air concentrations were shown to be not very sensitive to the deposition velocity and plume rise up to the maximum sampling distance 4 km.