ESTIMATION OF DRY DEPOSITION TO TREES ETC. BY INFERENTIAL METHOD AND A DISCUSSION FOR FOREST DAMAGE - OBSERVATION THROUGHOUT THE YEARS IN NARA CITY

A four-stage filter pack method (F-0: PTFE, F-1: polyamide, F-2: 6 %K2 CO3 + 2% glycerol impregnated and F-3: 5% phosphoric acid +2% glycerol impregnated filters) was used to sample the atmosphere for determinat ion of gas (SO2, HNO3, HCI, NH3) and particulate matter (SO42-, NO3-, Cl-, Na+, NH4+, K+, Ca2+, Mg2+) concentrations. The average concentrat ions of SO2, HNO3, HCl, NH3 gases and SO42-, NO3, Cl-, Na+, NH4+, K+, Ca2+ and Mg2+ particles were 76.2(1.83), 27.3(0.66), 31.8(0.76), 115(2 .76), 52.3, 47.7, 45.1, 34.4, 121, 9.4, 20.5 and 6.2 nmol/m(3) (ppb: 2 0 degrees C), respectively. The gases and particulate matter concentra tions were multiplied by dry deposition velocities for various surface s (bare soil, farmland, deciduous forest, coniferous forest) from the literature to estimate dry deposition. The coniferous forest received the greatest dry deposition of SO42- and NO3-. The average amounts of dry deposition of SO42- and NO3- estimated with data from a Wet/Dry co llector were 0.692 and 0.601 mol m(-2)/month, respectively, smaller th an the average amounts obtained with the inferential method. The contr ibution of dry deposition to total deposition was greater for gaseous species than for particulate matter. In the coniferious forest, the SO 42- and NO3- contributions to total dry deposition were 59 and 77%, re spectively. Forest damage cannot be fully evaluated by wet deposition measurements alone; estimate of dry deposition of HNO3 to coniferous f orests will advance our understanding of forest damage by acidic depos ition.