GRIDDED AMMONIA EMISSION FLUXES IN JAPAN

In order to fully understand the acidification of precipitation, it is essential to determine ammonia emissions. Detailed gridded emission f luxes of NH3 have been compiled in Europe. In East Asia they have been determined on a national basis (Zhao and Wang, 1994). In Japan we hav e calculated NH3 emission fluxes on a 1 degrees latitude x 1 degrees l ongitude basis for livestock and the application of fertilizer. Livest ock emission factors developed by W.A.H. Asman (Asman, 1992) for Europ e were used 23.04 and 5.36 kg NH3/animal/yr. for cattle (dairy cows an d beef), and pigs, respectively. Domestic animal population data was c ollected by prefecture and apportioned to grid cells based on the pref ectural area in each grid cell. For fertilizer emissions, NH3 emission were calculated assuming a 10% ammonium nitrogen evaporation rate far ammonium sulfate, urea and other nitrogen-containing fertilizers. Sin ce prefectural fertilizer data were not available, total fertilizer us age for Japan was distributed to prefectures based on cultivated area The maximum calculated NH3 emission fluxes for each of the three anima l categories were as follows: Dairy cows, 4730 (Hokkaido), beef cattle , 4540 (Kyushu) and pigs, 3480 (Kanto) tames NH3/grid/yr. The total NH 3 emissions due to livestock in Japan were 4.6, 6.0 and 4.4 x 10(4) to nnes NH3/yr. from dairy cows, beef cattle and pigs, respectively. The overall total NH3 emission from livestock and the application of ferti lizer was 2.0 x 10(5) tonnes NH3/yr. The NH3 emission by Japan is smal l compared to those of most European countries.