DETERMINATION OF IONIC CONCENTRATION IN ICE DURING FROSTS IN COASTAL SITES

The gas scavenging processes can be divided into wet and dry depositio n. There is a great discrepancy between emission and deposition values . So the ''specials events'', such as fog, dew and frost, are now bein g taken into consideration. In order to determine chemical-physical ch aracteristics and the scavenging effectiveness of frost, some samples were collected in the area of Ravenna, from December 1995 to February 1996. Four sampling sites differing one another for micrometeorologica l conditions were chosen. From chemical analyses of frosts, atmospheri c concentrations of SO2 and particles, and meteorological data, it has been possible to verify that pollutant concentrations in frost deposi ts may be indicative of the pollution level of the area in which sampl es are taken. Moreover, sulphate concentration depends linearly on tha t of sulphur dioxide present in the atmosphere.