Preliminary measurements of the particulate ionic component and SO2GAS contained in the air of a forestal area in the spanish basque country

One aspect of the EPOCA programme (Estudios en el Pirineo Occidental de Contaminacion Acida), the main goal of which is to show the possible effects of an acid rain type pollution on the forest of the Spanish Basque Country, is presented in this paper SO2 immissions have been measured as well as the ionic content both of aerosol and in the bulk deposit and in rainwater. The results show that the main ions found in the aerosol are SO42- and NH4+ (4.5 and 4.1 μg/m3 respectively). Precipitation is dominated by Cl-, NH4+, Ca2+ and SO42- (143.5, 142.8, 102.9 and 61.5 μeq/l). The bulk deposit shows maximum concentrations in SO42-, Ca2+ and NH4+ (9.0, 7.2 and 6.0 mg/m2 day). Losses of Cl- and NH4+ have been observed in the bulk deposit and lack of Ca2+ in the aerosol due to its presence in the latter in from of large size particles. (author)