Journal of Atmospheric Chemistry 48: 235–240, 2004. C  2004 Kluwer Academic Publishers. Printed in the Netherlands. 235 Determination of Sulfur Balance Between the Atmosphere and a Norway Spruce Forest Ecosystem: Comparison of Gradient Dry + Wet and Throughfall Deposition Measurements EMESE A. KOV ´ ACS 1 and L ´ ASZL ´ O HORV ´ ATH 2,∗ 1 Department of Chemical Technology and Environmental Chemistry, E¨ otv¨ os Lor ´ and University, P´ azm´ any P. s. 1/A, 1117 Budapest, Hungary 2 Hungarian Meteorological Service, Gilice t´ er 39, 1181 Budapest, Hungary, e-mail: horvath.l@met.hu (Received: 04 March 2003; accepted: 13 April 2004) Abstract. Total sulfur deposition was determined above a Norway spruce forest, in Hungary. Two methods were applied, on one hand dry + wet deposition measurements and on the other, throughfall and stemflow deposition estimations have been carried out. Results show: total depositions are 3.3 and 3.2 g S m −2 yr −1 determined by dry + wet and throughfall deposition methods, respectively. The share of the dry deposition in the total S-load is 73%. The agreement between the results of the two different methods is good and suggests the needlessness of complicated dry + wet flux measurements, i.e. the total and dry deposition of sulfur compounds to forests can be determined by simple throughfall and wet deposition measurements. Key words: dry deposition, forest ecosystem, S-balance, throughfall deposition, wet deposition 1. Introduction Forest ecosystems act as sink for atmospheric sulfur compounds. From the point of view of acidification and nutrient supply, deposition of sulfur compounds have a great importance. There are two samples, namely the gas-phase sulfur dioxide and the particulate phase sulfate, which have substantial concentrations in the atmosphere controlling the S-budget between the air and forest ecosys- tems. There are no important S-emission sources from the forest to the atmo- sphere, therefore only the deposition of sulfur dioxide and sulfate determines the S-balance. Sulfur compounds are deposited to the forest ecosystem both by wet (WD) and by dry deposition (DD) processes. Wet deposition can be calculated from the sulfate ion concentration measured in precipitation water and from the precipitation amount. In the dry deposition, both sulfate particles and sulfur dioxide can be adsorbed on the surfaces of canopy or soil. Adsorbed sulfur compounds are leached by the